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1
Brezas, Panagiotis Panos. "Time-domain optimal control for vehicle suspensions." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607986.
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Ma, Xin Bo. "Characteristic analysis, regulating mechanism modeling and advanced control on hydraulic adjustable dampers for automotive semi-active suspensions." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3951593.
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Graves, Kynan E., and kgraves@swin edu au. "Electromagnetic energy regenerative vibration damping." Swinburne University of Technology, 2000. http://adt.lib.swin.edu.au./public/adt-VSWT20060307.120939.
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This thesis documents a PhD level research program, undertaken at the Industrial
Institute Swinburne, Swinburne University of Technology between the years of 1997
and 2000. The research program investigated electromagnetic energy regenerative
vibration damping; the process of recovering energy from damped, vibrating systems.
More specifically, the main research objective was to determine the performance of
regenerative damping for the application of vehicle suspension systems. This question
emerged due to the need for continuous improvement of vehicle efficiency and the
potential benefits possible from the development of regenerative vehicle suspension. It
was noted, at the outset of this research, that previous authors had undertaken research
on particular aspects of regenerative damping systems. However in this research, the
objective was to undertake a broader investigation which would serve to provide a
deeper understanding of the key factors.
The evaluation of regenerative vibration damping performance was achieved by
developing a structured research methodology that began with analysing the overall
requirements of regenerative damping and, based on these requirements, investigated
several important design aspects of the system. The specific design aspects included an
investigation of electromagnetic machines for use as regenerative damping devices. This
analysis concentrated on determining the most promising electromagnetic device
construction based on its damping and regeneration properties. The investigation then
proceeded to develop an 'impedance-matching' regenerative interface, in order to control
the energy flows in the system. This form of device had not been previously developed
for electromagnetic vibration damping, and provided a significant advantage in
maximising energy regeneration while maintaining damping control. The results from
this analysis, when combined with the issues of integrating such a system in vehicle
suspension, were then used to estimate the overall performance of regenerative damping
for vehicle suspension systems.
The methodology and findings in this research program provided a number of
contributing elements to the field, and provided an insight into the development of
regenerative vehicle systems. The findings revealed that electromagnetic regenerative
vibration damping may be feasible for applications such as electric vehicles in which
energy efficiency is a primary concern, and may have other applications in similar
vibrating systems.
4
Huynh, Due Quoc. "Optimization of coulombic semi-active automotive suspension systems." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/16072.
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Falcone, Giovanni. "Air-spring suspension influence in fluid dynamic sloshing." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20190/.
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Il rollover di un veicolo, ossia la possibilità che esso possa ribaltarsi, è un fenomeno comune oggigiorno ed esso può essere causato da una serie di motivi, tra cui le condizioni del veicolo e della strada, le dimensioni del carico o eventuali errori da parte del conducente, che provocano fino al 78 % dei ribaltamenti. Le molle ad aria stanno guadagnando sempre più popolarità nel settore automobilistico e presentano numerosi vantaggi rispetto alle più classiche molle elicoidali. Le molle ad aria hanno molti vantaggi unici, come un comfort di marcia superiore, una riduzione dell'attrito, minore rumorosità ecc. Nella tesi realizzata, le molle ad aria vengono utilizzate nelle sospensioni di un'autocisterna al fine di esaminare l'effetto che esse determinano sul comportamento del veicolo ed in particolare sullo sloshing del fluido contenuto nella cisterna.
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Derrick, M. C. "A parallel polymer spring truck cab suspension system." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233119.
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Karlqvist, Rasmus. "Hydropneumatic suspension in a truck : Installation of a hydropneumatic suspension for a Scania truck." Thesis, Karlstads universitet, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-78647.
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Investigation and testing of hydropneumatic suspension systems has previously been done at Scania between the year 1992 and 2000. Interest has aroused at Scania CV AB to further test a hydropneumatic suspension. The reason being the new ventures of decarbonised, clean, electrified, automatized and digitalised vehicles. If electrified trucks are to be adopted in the market as an alternative to trucks with combustion engines, solutions for this type of vehicle’s capacity need to be presented. The vehicle’s weight needs to be reduced; the effectiveness of the components needs to be increased and alternatives to increase battery storage needs to arise if it’s going match the traveling distance of a combustion engine. The mission of the project is to present an installation solution of a hydropneumatic suspension that retains the performance of the current air suspension. The presented material will contain CAD-models of all the brackets that will be designed to fit the suspension, as well as the placement in the vehicle assembly for said brackets. The results show that as for the front suspension the best solution is a placement of the hydraulic cylinders in front of the vehicles front axle. Furthermore the rear suspension is best suited for a placement of the hydraulic cylinders behind the vehicles rear axle. However it was concluded that the rear suspension will not be able to retain the current stroke of the vehicle without sacrificing its ground clearance. Parts of the suspension could however be terminated when the air suspension system was replaced by the hydropneumatic system namely: The front suspension anti-roll bar, shock absorbers, air springs and their coexisting brackets.
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Christ, Florian. "Adaption and evaluation of transversal leaf spring suspension design for a lightweight vehicle using Adams/Car." Thesis, KTH, Fordonsdynamik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180035.
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This investigation deals with the suspension of a lightweight medium-class vehicle for four passengers with a curb weight of 1000 kg. The suspension layout consists of a transversal leaf spring and is supported by an active air spring which is included in the damper. The lower control arms are replaced by the leaf spring ends. Active ride height control is introduced to compensate for different vehicle load states. Active steering is applied using electric linear actuators with steer-by wire design. Besides intense use of light material the inquiry should investigate whether elimination of suspension parts or a lighter component is concordant with the stability demands of the vehicle. The investigation is based on simulations obtained with MSC Software ADAMS/Car and Matlab. The suspension is modeled in Adams/Car and has to proof it's compliance in normal driving conditions and under extreme forces. Evaluation criteria are suspension kinematics and compliance such as camber, caster and toe change during wheel travel in different load states. Also the leaf spring deflection, anti-dive and anti-squat measures and brake force distribution are investigated. Based on a simplified version of the leaf spring suspension design a full vehicle model is created. The comparison between the suspension models evaluates the same basic suspension parameters to ensure the compliance. Additionally roll rate and understeer gradient are investigated. It can be shown that the vehicle equipped with transversal leaf spring instead of lower control arms fulfils the set kinematics and compliance requirements. Road holding performance is assured for normal driving conditions on public roads.
9
Steward, Victoria. "Modeling of a folded spring supporting MEMS gyroscope." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-1007103-133256/.
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Zhao, Jing. "Design, control and testing of a novel hybrid active air suspension system for automobiles." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691888.
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Holtz, Marco Wilfried. "Modelling and design of a novel air-spring for a suspension seat." Thesis, Stellenbosch : University of Stellenbosch, 2008. http://hdl.handle.net/10019.1/2781.
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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008.Suspension seats are commonly used for earth moving machinery to isolate vehicle operators from vibrations transmitted to the vehicle body. To provide the required stiffness and damping for these seats, air-springs are typically used in conjunction with dampers. However, to eliminate the need for additional dampers, air-springs can be used in conjunction with auxiliary air volumes to provide both spring stiffness and damping. The damping is introduced through the flow restriction connecting the two air volumes. In this study, simplified models of an air-spring were derived followed by a model including the addition of an auxiliary volume. Subsequent to simulations, tests were performed on an experimental apparatus to validate the models. The air-spring models were shown to predict the behaviour of the experimental apparatus. The air-spring and auxiliary volume model followed the trend predicted by literature but showed approximately 27 % lower transmissibility amplitude and 21 % lower system natural frequency than obtained by tests when using large flow restriction diameters. This inaccuracy was assumed to be introduced by the simplified mass transfer equations defining the flow restriction between air-spring and auxiliary volume. The models however showed correlation when the auxiliary volume size was decreased by two thirds of the volume actually used for the experiment. This design of a prototype air-spring and auxiliary volume is presented for a suspension seat used in articulated or rigid frame dump trucks. The goal of this study was to design a suspension seat for this application and to obtain a SEAT value below 1,1. The design was optimised by varying auxiliary volume size, flow diameter and load. A SEAT value of less than 0,9 was achieved.
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Klavebäck, Erik. "Improved Weight Estimation for Vehicles with Air Suspension." Thesis, Uppsala universitet, Avdelningen för systemteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383247.
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The aim of this thesis is to explore and improve the accuracyofweight estimation in vehicles with air suspension. The main focushasbeen to understand the hysteresis and characteristics ofdifferentsuspension types used in Scania NCG trucks. The thesis hasled toinsights into the attributes affecting hysteresis and theaccuracy ofweight estimation. As a proof of concept a softwareimplementationhas been developed from the knowledge derived troughout the thesisto account for hysteresis. The result of this work hasproven it tobe possible to increase the accuracy and reduce the errorto lessthan half compared to today's method.
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KOTNI, DEEPAK. "A CAD/CAE DRIVEN AUTOMATED DESIGN OPTIMIZATION STUDY OF AUTOMOTIVE REAR SUSPENSION." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1130587319.
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Hidén, Teodor. "Low energy-cpnsuming load sensing truck cab suspension." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266943.
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In the development of battery electric trucks is one of the main concerns how to minimize the energy consumption of all the different subsystems on the truck. One of these energyconsuming systems is the active cab suspension. The load sensing (active) cab systems used today is using pressurized air, pneumatics, to keep the cab at correct ride height. Currently is this pressurized air produced with a big, bulky and heavy compressor that continuously is running to compress air for multiple different subsystems. The alternative to the load sensing active cab suspension is to use non-load sensing (passive) suspension. This option is limiting the comfort and appearance of the cab but is neither using any energy. The goal of this master thesis is to find a suspension solution that is both load sensing and energy-efficient. To find a suitable load sensing solution was cab suspension system on other types of heavy machines inspected, together with suspension systems overall. There could be seen that the use of hydraulics gave the adjustability needed, without consuming any energy when the adjustments had been done. The system could also be very compact. It is easy to adapt the existing suspension components to work together with the hydraulic cylinders, and the hydraulic suspension systems have the possibility to be merged with other hydraulic systems on the truck.I utvecklingen av el- och batteridrivna lastbilar är en stor del av utmaning att minimera energianvändningen hos lastbilens alla olika delsystem, där ibland hyttfjädringen. Dagens lastkännande (aktiva) fjädringssystem på lastbilshytter drivs med tryckluft och arbetar kontinuerligt med att hålla lastbilshytten på rätt höjd. Tryckluften kommer ifrån en stor och tung kompressor som ständigt arbetar för att komprimera luft till lastbilens alla olika delsystem. Alternativet till den aktiva lastkännande hyttfjädringen är att använda en icke lastkännande (passiv) fjädring. Detta begränsar dock lastbilens komfort och utseende, men förbrukar heller ingen energi. Målet med detta examensarbete var att finna en fjädringslösning som både är lastkännande och energieffektiv. För att hitta en lämplig lastkännande lösning gjordes en grundlig undersökning av hyttfjädringslösningar på andra tunga fordon, samt olika fjädringssystem överlag. Det visade sig att användandet av hydraulik ger en tillfredsställande justerbarhet, utan att förbruka någon energi när systemet är i vila (inte aktivt justerar). Systemet skulle även kunna göras mycket kompakt. Det är lätt att anpassa dagens befintliga fjädringskomponenter för att kunna fungera ihop med justerbara hydraulcylindrar, och fjädringens hydraulsystem skulle kunna drivas ihop med övriga hydraulsystem på lastbilen.
15
Tran, Michael. "Neural network identification of quarter-car passive and active suspension systems." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09292009-020158/.
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Barnard, Charl. "Design, development and testing of a 2-DOF articulated dump truck suspension seat." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1845.
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MScEngThis project entails the design and development of a new 2-DOF articulated dump truck (ADT) suspension seat. A study of the ADT vibration environment was conducted using data measured with accelerometers inside the cabin. With the system’s required operational capabilities determined, the concept design phase resulted in a feasible concept. The first prototype was manufactured based on the initial set of specifications. A variety of numerical modelling techniques were used to analyse and evaluate the seat’s dynamic response. Vertical and lateral laboratory tests of the suspension seat with human occupants were completed. The vertical lumped parameter model of the suspension seat with a human occupant gave good correlation with the laboratory measured frequency response. A broad band input signal, and not the ISO 7096 (2000) EM1 signal, was used to obtain the frequency response used to verify the lumped parameter model. The SEAT values for the ISO 7096 (2000) EM1 signal and various ADT road conditions were calculated using the lumped parameter models for a small, medium and large subject, the same three subjects used in the laboratory tests. SEAT values using the ISO 7096 (2000) EM1 signal of 0.94, 0.93 and 0.88 were obtained for the small, medium and large subjects. The lowest SEAT values obtained using the road data were 0.63, 0.56 and 0.48 for the small, medium and large subjects. The transmissibility curves determined from the lateral laboratory tests were used to calculate the SEAT values for the lateral ADT cabin vibrations. The lowest SEAT values obtained were 0.83, 0.83 and 0.82 obtained for the small, medium and large subjects. After all the results from the testing and modelling were evaluated the design was assessed. All the data and information collected was used as input for the design of a second prototype, which was not manufactured. Not all the set specifications were achieved for the first prototype, but the new suspension seat gave comparable vertical vibration isolation performance to that of expensive commercially available ADT suspension seats. The lateral suspension demonstrated good lateral vibration isolation and is a feature not currently available in current ADT suspension seats.
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Kirstein, Johannes Cornelis. "Suspension system optimisation to reduce whole body vibration exposure on an articulated dump truck." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/2539.
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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005.In this document the reduced order simulation and optimisation of the passive suspension systems of a locally produced forty ton articulated dump truck is discussed. The linearization of the suspension parameters were validated using two and three dimensional MATLAB models. A 24 degree-of-freedom, three dimensional ADAMS/VIEW model with linear parameters was developed and compared to measured data as well as with simulation results from a more complex 50 degree-of-freedom non-linear ADAMS/CAR model. The ADAMS/VIEW model correlated in some aspects better with the experimental data than an existing higher order ADAMS/CAR model and was used in the suspension system optimisation study. The road profile over which the vehicle was to prove its comfort was generated, from a spatial PSD (Power Spectral Density), to be representative of a typical haul road. The weighted RMS (Root Mean Squared) and VDV (Vibration Dose Value) values are used in the objective function for the optimisation study. The optimisation was performed by four different algorithms and an improvement of 30% in ride comfort for the worst axis was achieved on the haul road. The improvement was realised by softening the struts and tires and hardening the cab mounts. The results were verified by simulating the optimised truck on different road surfaces and comparing the relative improvements with the original truck’s performance.
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Kat, Cor-Jacques. "Suspension forces on a tri-axle air suspended semi-trailer." Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-06242009-153546/.
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Chaudhary, Sanjeev. "Ride and roll performance analysis of a vehicle with spring-loaded interconnected hydro-pneumatic suspension." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0004/MQ39478.pdf.
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Žák, Ondřej. "Konstrukční návrh nesymetrické parabolické pružiny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-377480.
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This thesis is focused on design of parabolic spring for a truck. Characteristics of the spring are designed with respect to loads during heavy braking. Thesis contains a brief summary of current truck suspension, the spring design and suggestion for testing methodology for longitudinal load.
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Stroud, Trevor. "Enhancing vehicle dynamics through real-time tyre temperature analysis." Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/d1020599.
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Vehicle suspension optimisation is a complex and difficult task, as there are a variety of factors influencing the dynamic performance of a vehicle. During suspension development, the optimisation of a selected few of these factors is often to the detriment of others, as they are all inter-related. In addition, expertise in vehicle setup and suspension tuning is scarce, and is limited to experienced racing teams and large automotive manufacturers with extensive research and development capabilities. The motivation for this research was therefore to provide objective and user-friendly methodologies for vehicle suspension optimisation, in order to support student projects like Formula Student, while having relevance to the needs of the South African automotive industry and racing community. With the onset of digital data acquisition, it has become feasible to take real-time measurements of tyre temperatures, to provide information on how a tyre is performing at a specific point on the track. Measuring the tyre surface temperature can provide a useful indication on whether the tyre is loaded equally or not, and what suspension adjustments should be made to improve tyre load distribution.
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Quartaroli, Matheus Mikael. "Análise dinâmica de um sistema de atuação eletromecânica em mecanismo de suspensão mecânica para isolamento de vibrações." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153314.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Esse trabalho buscou investigar os comportamentos dinâmicos de uma suspensão eletromecânica. Para a configuração dessa suspensão substitui-se o amortecedor viscoso convencional por um amortecedor do tipo eletromecânico. O amortecedor eletromecânico é formado por um transdutor de imã permanente e bobina móvel, no qual se acopla ao sistema mecânico com o eletromagnético. Nos terminais da bobina é introduzido um circuito elétrico RLC ligados em série. Para modelagem e a obtenção das equações dinâmica que descrevem seu movimento utilizou-se o método de Lagrange, que utiliza expressões de energia. Os modelos abordam absorvedores utilizados na indústria automobilística. No trabalho, primeiramente foi investigado a capacidade dos parâmetros elétricos no comportamento do sistema, e verificou-se a influência que a resistência elétrica e a capacitância tem em relação ao deslocamento da massa suspensa de um veículo. Foi realizada, através da função transferência, uma análise da quantidade de energia obtida no sistema elétrico para valores diferentes de resistência elétrica e em comparação foi verificado o ganho da massa suspensa para um movimento harmônico sofrido pela base. Por fim, investigou-se as potências geradas no circuito elétrico e o fator de potência para diferentes valores de capacitância. E também apurou a influência da resistência elétrica na produção de potência ativa. Os resultados mostraram a influência dos parâmetros elétricos no comportamento dinâmico do sistema e na geração de potência elétrica, assim através de um controle feito nesses parâmetros pode-se encontrar faixas no qual reduz a transmissibilidade de deslocamento para os ocupantes de um veículo e geram uma alta potência elétrica em que possa ser armazenada e utilizada posteriormente.
This work sought to investigate the dynamic behavior of an electromechanical suspension. For the configuration of this suspension it replaces the conventional viscous damper with a shock absorber of the electromechanical type. The electromechanical damper is formed by a permanent magnet transducer and mobile coil, in which it couples the mechanical system with the electromagnetic. At the terminals of the coil is introduced an RLC electric circuit connected in series. For the modeling and the obtaining of the dynamic equations that describe its movement was uses the Lagrange method, that uses expressions of conservation of energy. The models approach in a simplified way the absorbers used in the automotive industry. In the work, it was first investigated the influence of the electrical parameters on the behavior of the system, it was verifies the power of the electrical resistance and the capacitance have in relation to the displacement of the suspended mass of a vehicle. It was performed, through the transfer function, an analysis of the amount of energy obtained in the electrical system is performed for different values of electrical resistance and in comparison it was verifies the gain of the suspended mass for a harmonic movement suffered by the base. Finally, we investigated the powers generated in the electric circuit and the power factor for different capacitance values. It also determined the influence of electrical resistance on the production of active power. The results showed the influence of the electrical parameters on the dynamic behavior of the system and the generation of electric power, so through a control made in these parameters can be found tracks in which reduces the transmissibility of displacement for the occupants of a vehicle and generate a high electrical power where it can be stored and used later.
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Dubois, François. "Étude par spectroscopie Raman de la corrosion d’aciers à ressorts de suspension automobile." Grenoble INPG, 2008. http://www.theses.fr/2008INPG0003.
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Pour améliorer notre description de la corrosion des aciers à ressort hélicoïdaux de suspension automobile, nous avons réalisé une étude bibliographique qui nous permet de faire le point sur les connaissances établies en corrosion atmosphérique d’aciers peu alliés. Si la plupart des produits de corrosion sont connus et que des observations sur leur répartition dans la couche d’oxyde convergent, il reste des interrogations sur les mécanismes qui y conduisent et sur l’influence relative des éléments d’alliages sur la résistance à la corrosion. Nous avons évalué la capacité de la spectroscopie Raman, de la spectroscopie IR et de la diffraction des RX à caractériser les oxydes de références et des mélanges de phases. Des outils et des protocoles expérimentaux ont été élaborés pour l’étude en coupe de produits de corrosion sur leur substrat d’acier. La lépidocrocite, dont le rôle important dans des conditions cycliques de corrosion a été avancé dans la littérature, a fait l’objet d’une étude plus approfondie dans laquelle une attribution des modes Raman est proposée. La caractérisation des couches de produits de corrosion qui se développent sur 10 nuances industrielles en brouillard salin nous a permis d’établir la répartition globale des produits de corrosion. L’écaille d’oxyde qui se détache du substrat pour une corrosion avancée, est constituée de lépidocrocite dans la partie extérieure, de goethite plus en profondeur et enfin d’un mélange de maghémite, d’akaganéite et de goethite dans la partie interne. À l’interface métal oxyde, nous avons mis en évidence la présence de zones de corrosion localisée sur l’ensemble des nuances après 14 cycles. La présence d’akaganéite dans ces zones suggère un mécanisme de propagation de piqûres proche de celui établi sur les aciers inoxydables. Des différences entre les nuances les plus résistantes et les autres ont été mises en évidence à l’interface métal-oxyde dans les zones les moins corrodées et pour une corrosion avancée : la goethite et la maghémite sont les phases qui prédominent sur les nuances peu résistantes alors qu’une part significative de ces zones est constituée d’un composé possédant un nouveau spectre Raman sur les nuances les plus résistantes. L’étude de nuances mono alliées nous permet de mettre en relation des enrichissements relatifs avec la présence de l’une ou l’autre phase d’oxyde. La couche à l’interface métal-oxyde de la nuance au chrome corrodée à 3 cycles, est composée presque exclusivement du composé nouveau qui s’enrichit lui-même en chrome. L’adaptation d’un modèle de prédiction de la corrosion atmosphérique aux nuances d’acier à ressorts en conditions de corrosion en brouillard salin confirme l’effet bénéfique du chrome, du nickel, du titane et du phosphore et souligne un rôle néfaste du molybdène dans ces conditions très agressivesThe aim of this study was to improve our description of the corrosion process of helical suspension spring steels. A review of the articles about corrosion of low alloyed steels alloyed us determine the major corrosion products, their typical repartition and mechanisms that lead to an increase in corrosion rate during wet-dry cycles. But there stood unsolved questions about these mechanisms and relative influences of alloying elements in the problem we were interested in. We have investigated the ability of Raman spectroscopy, IR spectroscopy and XR diffraction through characterizing pure powders and mixtures of reference compounds. Tools and experimental routes have been developed in order to study cross sections of corroded samples. Lepidocrocite, which is said to play an important role in corrosion mechanisms during wet-dry cycles, had been studied: an attribution of Raman modes is proposed. The study of corrosion scales that grow on 10 different steel grades allowed us to confirm the global repartition of corrosion products after salt spray treatment. A spall of corrosion products that have been removed from the steel substrate is made up of lepidocrocite in the outer part, goethite deeper in the oxide interface on every grade after 14 cycles. The appearance of akageneite in these areas suggests a propagation step close to what is known for pitting corrosion on stainless steels. Differences between corrosion of resistant and less resistant steel grades had been enlightened in the corrosion products on flatter parts of the metal oxide interface after more than 14 cycles. Maghemite and goethite are the major components in these parts on the less corrosion resistant steel grades, and an unidentified compound that has a new Raman spectrum is significantly detected in these flatter parts on most resistant grades. Mono alloyed steels are tested in corrosion under salt spray conditions. We pointed out enrichments in alloying elements of some iron oxides, especially a chromium enrichment in the new compound that covers the whole metal oxide interface on the Cr-grade. A prediction model for atmospheric corrosion has been adapted to describe corrosion of spring steel grades in salts spray cyclic conditions. The beneficial effect of chromium, nickel, titanium and phosphor on corrosion resistance was confirmed, and a harmful effect of molybdenum was pointed out in these very aggressive conditions
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Micheletti, Marcelo. "Análise comparativa da dirigibilidade de um veículo na sua versão com suspensão elevada em ambiente multicorpos." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264354.
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Orientador: Pablo Siqueira MeirellesDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: No projeto de novos veículos automotores as empresas utilizam o conceito de plataformas mundiais visando reduzir os custos de desenvolvimento, possibilitando a criação de diferentes veículos a partir de uma mesma plataforma básica. Alguns modelos conforme características mercadológicas locais requerem a alteração da atitude de suspensão com a utilização de suspensões elevadas e pneus com diâmetro maior. Estas alterações afetam diretamente a dirigibilidade do veículo. O objetivo deste trabalho é desenvolver uma metodologia de estudo da dinâmica lateral de um veículo identificando as principais características que influenciam no comportamento da dirigibilidade do veiculo com suspensão elevada. Foram utilizadas ferramentas computacionais para simulação de sistemas multicorpos onde foram utilizados modelos não lineares de batentes, mancais de suspensão e amortecedores. Este trabalho demonstra o efeito da alteração de características como ângulo de Ackerman, a relação de direção, a altura do eixo de rolagem, rigidez da barra estabilizadora dianteira e taxa de variação da convergência no comportamento de dirigibilidade de um veículo no estado estacionário e no estado transitório
Abstract: In the design of new automobile companies use the concept of global platforms to reduce development costs, enabling the creation of different vehicles from the same basic platform. Some models as marketing local features require changing the attitude of suspension with the use of high suspensions and tires with larger diameter. These changes directly affect the behavior of the vehicle handling. The objective is to develop a methodology to study the lateral dynamics of a vehicle identifying the main characteristics that influence the behavior of driving the vehicle with high suspension. With the aid of computational tools for simulation of multi body systems which were used nonlinear models of bump stops, suspension bushes and shock absorbers. This work demonstrates the effect of changing characteristics such as Ackerman angle, the steering ratio, the height of the roll center axis, front suspension anti roll bar stiffness and ride steer influence in the behavior of a vehicle driving at steady state and transient state
Mestrado
Dinâmica
Mestre em Engenharia Automobilistica
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Bouvin, Jean-Louis. "Vers une version alternative à la suspension CRONE Hydractive." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0042/document.
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La suspension CRONE Hydractive, développée par l’équipe CRONE dans le cadre des suspensions de véhicules automobiles, présente des performances remarquables. En effet, l’association de l’approche CRONE, garantissant la robustesse du degré de stabilité aux variations de la masse suspendue, et de la stratégie Hydractive, permettant la commutation d’une architecture de suspension orientée confort vibratoire à une autre orientée comportement routier,permet la mise en défaut de la plupart des dilemmes inhérents aux architectures traditionnelles de suspension. La présente étude propose ainsi le développement d’une version alternative de la suspension CRONE par deux approches. Une première approche consiste en la mise en place d’une version passive métallique reposant sur l’utilisation des ressorts à lames en s’inscrivant dans une démarche de modernisation et d’optimisation des technologies historiques. La seconde approche, quant à elle, consiste à proposer le développement d’une version active pneumatique de la suspension CRONE. La modélisation complète de l’architecture « CRONE » orientée confort est alors proposée à travers celle de ses accumulateurs et gicleurs pneumatiques. Cette nouvelle version de suspension, en adoptant une technologie d’actualité de plus en plus répandue et pouvant bénéficier des développements du Véhicule Autonome Connecté, ouvre de nouvelles perspectives d’évolution de la suspension automobileThe Hydractive CRONE car suspension developed by the CRONE team provides outstanding performances. Indeed, the CRONE method ensures the robustness of the stability degree with respect to variations of the sprung mass, while the Hydractive strategy enables the switchover between a comfort-oriented architecture and a road-behavior-oriented one. The association of the CRONE method with the Hydractive strategy allows to circumvent most of the dilemmas that occur with traditional architecture suspensions. The present study aims to develop an alternative version of the CRONE suspension using two approaches. A first approach consists of the implementation of a passive metallic version based on leaf springs aiming the modernisation and optimisation of historical technologies. The second one, however, involves the use of a more relevant and increasingly widespread technology with the development of an active pneumatic version of the CRONE suspension. The complete modeling of the ``CRONE'' comfort-oriented architecture is then proposed through its pneumatic accumulators and nozzles. This new version, benefiting from the pneumatic active system and from the development of the Autonomous Connected Vehicle, opens up new prospects for the development of car suspensions
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Thoresson, Michael John. "Mathematical optimisation of the suspension system of an off-road vehicle for ride comfort and handling." Diss., Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-11162005-155118.
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Kong, Yat Sheng [Verfasser], and Dieter [Akademischer Betreuer] Schramm. "Establishment of artificial neural network for suspension spring fatigue life prediction using strain and acceleration data / Yat Sheng Kong ; Betreuer: Dieter Schramm." Duisburg, 2019. http://d-nb.info/1191692558/34.
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Rexer, Manuel, Nicolas Brötz, and Peter F. Pelz. "Much does not help much: 3D pareto front of safety, comfort and energy consumption for an active pneumatic suspension strut." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71215.
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With regard to autonomous driving the demands on comfort are increasing. This makes it attractive to use active suspension systems. The system developed at TU Darmstadt is able to increase driving comfort up to 28 % while maintaining driving safety compared to a passive suspension system. This paper investigates the influence of available energy and power of the active system. The investigation is based on a simulation of a quarter car model and an uneven country road. This paper shows that the more energy the active system has at its disposition, the greater is the range between a comfortable and a sporty chassis. Furthermore the driving comfort can be increased by 28 % with constant driving safety. The average power required for this is 15 W and the maximum power is 300 W.
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Hattori, Carolina Sayuri. "Comparação de molas de suspensão temperadas e revenidas enroladas a quente e a frio." Universidade Presbiteriana Mackenzie, 2012. http://tede.mackenzie.br/jspui/handle/tede/1327.
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Previous issue date: 2012-02-10IPEN - Instituto de Pesquisas Energéticas e Nucleares
The fatigue and toughness resistance are properties that exerts a strong influence on the spring suspension performance in the vehicles. The choice of SAE 9254 steel is due to the wide utilization in the springs fabrication and to have fatigue and toughness properties. The manufacture of SAE 9254 spring steel has been made by hot rolling process and submitted to heat treatment of quenching and tempering by conventional process or by cold process with induction heat treatment. Therefore, it is important to study the performance of this steel in these two processes. This study investigated the effect of the two production process and compared hardness and fatigue mechanical properties. The hardness is compatible with the heat treatment and the microstructure present in each condition. The shot peening induced a compressive residual stress which increased the fatigue life of SAE 9254 steel. The residual stress profile from the surface of springs showed a peak in the values of compressive stress for both manufacturing processes. The maximum residual stress in the cold processed spring was higher than the hot processed spring and maintained much higher values along the thickness of the spring from the surface, resulting from manufacturing processes. The fatigue cracking of the springs, produced by both process without shot peening, started by torsional fatigue process, with typical macroscopic propagation, showing stretch marks with high plastic deformation depending on the request type that accentuates the shear stresses.
A resistência à fadiga e a tenacidade são propriedades que exercem uma grande influência no desempenho das molas de suspensão dos veículos. A escolha do aço SAE 9254 ocorreu devido à sua ampla utilização na fabricação dessas molas e por possuir propriedades de fadiga e tenacidade. A fabricação de molas do aço SAE 9254 tem sido feita pelo processo de enrolamento a quente e submetido a tratamentos térmicos de têmpera e revenimento convencional ou pelo processo a frio e têmpera e revenimento por indução. Portanto, torna-se importante estudar o desempenho desse aço nesses dois processos. Esse trabalho investigou o efeito dos dois processos de produção e comparou as propriedades mecânicas em fadiga e dureza. Os valores de dureza das molas nas diversas condições investigadas estão compatíveis com o tratamento térmico e com a microestrutura presente em cada condição. O jateamento das molas induziu a uma tensão residual compressiva que aumentou consideravelmente a resistência à fadiga do aço SAE 9254. O perfil de tensão residual a partir da superfície das molas jateadas apresentou um pico nos valores de tensão de compressão para ambos os processos de fabricação. A tensão residual máxima na mola processada a frio e jateada foi superior à da mola processada a quente e mantiveram valores bem mais elevados ao longo da espessura da mola a partir da superfície, decorrentes dos processos de fabricação. As trincas por fadiga das molas fabricadas por ambos os processos sem jateamento tiveram seu início pelo processo de fadiga torcional, com propagação macroscópica típica, apresentando sinais de estrias com elevada deformação plástica em função do tipo de solicitação que acentua as tensões de cisalhamento.
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Yacoub, Gebran, and Ahad Nibour Abdul. "Framtagning av upphängningssystem till en robot." Thesis, KTH, Hållbar produktionsutveckling (ML), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300130.
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Med den kontinuerliga automationen och de globala mål som syftar till miljövänliga och grönare samhälle, bildades företaget TerraGo Deliveries med syfte att minimera växthusgasersutsläpp i stora städer genom hållbarare logistik. Deras mål är att bygga en robot som levererar mat från restauranger till kunder. Roboten ska gå på gångställe med människor för att minska trafiken i körfälten. Vanligtvis, går leveransen genom chaufförer som kör bilar eller moped som orsakar mer gasutsläpp och mer trängsel i trafik samt risk för olyckor. Det här projektet går ut med att framta ett upphängning system till första prototypen av TerraGo Deliveries robot som är sexhjuldriven. Det nya systemet ska klara sig med att gå på grusvägar och gå på trottoars kanter. För att komma fram till den slutliga designen så delas projektet in i flera olika delmoment som består av faktainsamling för upphängning system till olika fordon och robotar, skisser, mekanikberäkningar, CAD modellering, 3D-printing, värklighetstester, konceptutveckling och materialval. CAD-programmet Creo Parametric 5.0 har använts för att skapa 3D-modeller för de olika koncepten. Samt programmet Granta EduPack, som är ingenjörsmässigt materialdatabas, har varit ett verktyg för materialvalet. Dessutom renderingar på den slutliga designen har utförts med hjälp av KeyShot 10 för att visa hur den kommer se ut på verkligheten. Resultatet kommer att redovisa upphängningssystemet som en 3D-modell som visar hur den kommer att lösa problemet med hänsyn till montering anvisningar. Materialvalet för systemet hamnar på aluminiumlegeringen SS 4212–06.With the continuous automation and the global goals that aim to more environmentally friendly and greener society, the company TerraGo Deliveries was formed with purpose of minimizing greenhouse gas emissions in large cities through more sustainable logistics. Their goal is to build a robot that delivers food from restaurants and shops to customers. The robot will go on the pavement at peoples’ speed to reduce traffic in the lanes. Usually, the delivery goes through drivers who drive cars or scooters that cause more gas emissions and more congestion in traffic as well as the risk of accidents. This project involves developing a suspension system for the first prototype of the TerraGo Deliveries robot, which is six-wheel drive. The new system will be able to go on gravel roads and climb on the curbs without any problem. To reach at the final design, the project has been divided into several different phases that consist of fact collection for suspension systems for different vehicles and robots, sketches, mechanical calculations, CAD-modeling, 3D-printing, reality tests, concept development and material selection. The CAD program Creo Parametric 5.0 has been used to create 3D models for the various concepts. And the program Granta EduPack, which is an engineering material database, has been a tool for material selection. In addition, renderings of the final design have been performed using KeyShot 10 to show how it will look like in reality. The result will present the suspension system as a 3D-model that shows how it will solve the problems, which are introduced in the report, with the assembly instructions. The choice of material for the system ends up on the aluminum alloy SS 4212–06.
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Iezzo, Robson. "Desenvolvimento de um sistema de suspensão com amortecimento semi-ativo "slow-active" com custo competitivo." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263841.
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Orientador: Douglas Eduardo ZampieriDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Neste trabalho é realizado o desenvolvimento de um sistema de suspensão semi-ativo adaptativo com baixo custo de implementação, quando comparado aos sistemas semi-ativos atualmente disponíveis no mercado. Para isto, foi caracterizado um sistema de amortecimento passivo variável controlado remotamente (com dispositivo seletivo alocado no painel do veículo), o qual está atualmente em desenvolvimento pela empresa. A arquitetura desse sistema, prevendo atuadores eletrônicos e central eletrônica de processamento com interface e coleta de informações da rede CAN, foi concebida para, através da definição de uma lógica de controle, transformá-lo em um sistema de suspensão semi-ativo com custo competitivo. Procedeu-se investigando e estabelecendo parâmetros de controle e sinais existentes nos subsistemas dos veículos modernos para alimentação de uma lógica matricial de controle. Identificados os sinais possíveis de se utilizar na alimentação dessas matrizes, foram realizadas diversas simulações em software de dinâmica veicular para verificação dos parâmetros de controle definidos, assim como do comportamento dinâmico do veículo, com o objetivo de otimizar o compromisso entre conforto e estabilidade. Com base neste processo, foram estabelecidas matrizes lógicas de comando aos amortecedores eletrônicos as quais, através da identificação do nível dos parâmetros recebidos do veículo e da atitude do motorista ao volante, definem automaticamente qual a melhor curva de amortecimento a ser empregada, dentro de um universo discreto de curvas, para uma dada condição de utilização do veículo. O resultado deste trabalho busca viabilizar a aplicação de sistemas inteligentes de suspensão no mercado automobilístico nacional, o qual é atualmente composto em 100% por sistemas de suspensão passivos.
Abstract: This work is dedicated to develop an adaptive semi-active suspension system at a low cost of implementation, when compared to semi-active systems currently available. For that was characterized a passive damping system variable remotely controlled (with a selective device allocated on the panel of the vehicle), which is currently under development by the company. The architecture of this system, providing electronic actuators and electronic control unit interface and gathering information from the CAN network was designed for, by setting a control logic, transform it into a semi-active suspension system at a competitive cost. The work proceeded investigating and establishing parameters and existing signals in the subsystems of modern vehicles to feed a logical matrix of control. Identified the possible signals available to using on the mentioned matrix, several simulations were carried out in a vehicle dynamics software in order to check the applicability of those control parameters defined, as well as the dynamic behavior of the vehicle with the goal of optimizing the balance between ride and handling. Based on this process were established a set of logical matrix to command the electronic dampers which, by identifying the level of the parameters received from the vehicle and the attitude of the driver at the steering wheel, define automatically the best damping curve to be used, within an universe of discrete curves, for a given driving condition. The result of this work aims to become viable the application of intelligent suspension systems in domestic automotive market which is nowadays composed by 100% of passive suspension systems.
Mestrado
Dinâmica
Mestre em Engenharia Automobilistica
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Antonio, Sergio Francisco Dela. "Estudo da sobrecarga dinamica em caminões por meio de medições diretamente no veiculo." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263951.
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Orientador: Auteliano Antunes dos Santos JrDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: As cargas dinâmicas que ocorrem em veículos de carga quando estes estão em movimento, são fortemente responsáveis pela deterioração precoce do piso asfáltico das rodovias e logradouros no Brasil. Também são umas das principais responsáveis pelo desgaste excessivo e prematuro dos componentes do veículo. Estes dois fatores fazem com que os custos de transporte rodoviário no Brasil, de mercadorias e bens, fiquem mais elevados. O objetivo deste trabalho é avaliar uma metodologia para medir as cargas dinâmicas que ocorrem em veículos de carga. Na metodologia proposta, utilizou-se a própria suspensão do veículo como parte do sistema de medição, no caso, veículos com suspensão com feixes de molas. O sistema de medida das cargas dinâmicas é composto pelos feixes de molas e um transdutor de deslocamento. Gerou-se a curva de resposta do feixe de molas com relação aos deslocamentos ocorridos através da aplicação das cargas. Após os estudos preliminares, implantou-se este sistema na suspensão dianteira de um veículo de carga de porte médio. Estimaram-se as cargas dinâmicas em várias condições de piso com o veículo carregado, a partir dos deslocamentos medidos. Os resultados mostram que o sistema funcionou satisfatoriamente, e foi possível quantificar os níveis de cargas dinâmicas ocorridas em casos mais críticos. O maior nível encontrado foi de 33,9% acima da carga estática no lado esquerdo da suspensão dianteira, no trecho com lombadas.
Abstract: The dynamical loads and forces occurring in cargo vehicles under movement are among the major causes of the early deterioration on highway and road pavement in Brazil. These dynamical loads are also responsible for the premature and excessive wear on several vehicle components. These two factors combined are among the main reasons why road transportation costs are so expensive in Brazil. The objective of this work is to suggest and evaluate a methodology for measuring the dynamical loads and forces on moving cargo vehicles. This methodology utilizes the suspension system of the vehicle itself as part of the measurement system. In the experimental part of this study a force measuring system was conceived using the leaf spring assembly of the vehicle suspension combined with a simple displacement transducer strategically installed in the vehicle suspension. This force measuring system was installed in a mid-range cargo truck. The characteristic curve of the suspension leaf spring set was determined by the application of static loads onto the vehicle. After calibration and fine adjustments of the system, several experimental runs were performed in the loaded vehicle, measuring the dynamic loads in several pavement types and traffic conditions. The results showed that the system worked satisfactorily, and it was possible to determine the dynamic loads occurred on all experimental runs. The greatest dynamic load found in the field was 33,9 % above the static load on the left front suspension.
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
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Gonçalves, Maria Aline. "Controle SDRE aplicado em suspensão veicular com amortecedor magneto-reológico." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2533.
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Desde que se inventou o automóvel, a suspensão veicular é objeto de pesquisa e estudo. A função do sistema de suspensão de um veículo é minimizar a aceleração vertical, isolando os passageiros de choques e vibrações promovendo conforto, reduzindo a fadiga o que beneficia a saúde e segurança dos motoristas. Este trabalho apresenta uma proposta para o controle da suspensão veicular utilizando um controlador SDRE aplicado ao amortecedor magneto-reológico. A eficiência do controle proposto pode ser evidenciada através de simulações computacionais utilizando um modelo matemático não linear de um quarto de carro e um modelo matemático não-lienar de meio de carro. A análise do desempenho do controle é realizada considerando excitações provocadas por irregularidades da estrada representadas por entradas do tipo degrau e senoidal. As simulações computacionais foram realizadas utilizando o programa Matlab®. Os resultados das simulações evidenciam que o controle proposto melhora dirigibilidade do veículo ao reduzir o deslocamento vertical do conjunto eixo-roda e contribui com o conforto dos passageiros reduzindo as oscilações na carroceria. Adicionalmente, foram realizadas análises de simulações de variações paramétricas afim de se verificar o comportamento do controle proposto diante de incertezas. Os estudos paramétricos demonstram que o controle permanece estável, mesmo quando submetido a variações paramétricas.Since car was developed, vehicular suspension is an object of research and study. The function of the suspension system of a vehicle is to minimize vertical acceleration, isolating passengers from shocks and vibrations promoting comfort, reducing fatigue which benefits the health and safety of drivers. This work presents a proposal for the control of vehicle suspension using an SDRE controller applied to the magneto-rheological damper. The efficiency of the proposed control can be evidenced through computational simulations using a quarter-car nonlinear mathematical model and a half-car nonlinear mathematical model. The analysis of the controller's performance is performed considering the excitations caused by irregularities of the road represented by step input and sinusoidal. Computational simulations were performed using Matlab®. The simulation results show that the proposed control improves the vehicle's dirigibility by reducing the vertical displacement of the wheel and also contributes to the passengers' comfort by reducing oscillations in the vehicle's body. In addition, simulations of parametric variations were performed in order to verify the behavior of the proposed control in face of uncertainties. Parametric studies demonstrate that control remains stable, even when subjected to parametric variations.
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Oliveira, Fernando Emerenciano Nunes de. "Controles semiativos e observador de estados não linear aplicados em suspensão veicular com amortecedor magneto-reológico." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2904.
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Comprovadamente, o sistema de suspensão veicular passivo é uma proposta confiável e econômica de solução tanto para redução dos níveis de vibração do chassi e da roda, quanto para a redução dos níveis de aceleração do chassi. Embora este sistema seja amplamente empregado nos veículos, ele apresenta a desvantagem que seus parâmetros não podem ser modificados de acordo com as variações geradas pela pista. Com isso surge o emprego da utilização do sistema de suspensão ativa, que possibilita a variação dos parâmetros da suspensão a tempo real, no entanto, o emprego deste tipo de suspensão requer um elevado nível de energia para o funcionamento correto de seus atuadores, acarretando na inviabilidade de algumas aplicações. Para solucionar as desvantagens encontradas para o sistema de suspensão passivo e ativo, surge o sistema de suspensão semiativo, que reúne as vantagens do sistema ativo, porém com um menor consumo de energia, gerando consequentemente uma opção de controle confiável e econômica de solução para os problemas de dirigibilidade e conforto veicular. O presente trabalho pretende realizar duas avaliações, sendo a primeira, a avaliação e comparação de um sistema de suspensão passivo com o desempenho de quatro controladores semiativos (on/off, skyhook, groundhook e híbrido) e a segunda é testar os mesmos controladores, porém considerando a dinâmica de um amortecedor magnético-reológico através do modelo de LuGre. Estes controladores serão aplicados a um modelo não linear de um quarto de carro com dois graus de liberdade, sendo as suas variáveis estimadas, através de um observador de estados não linear. A análise para a comparação dos sistemas será realizada através de simulações numéricas utilizando o software MatLab®. As simulações dos distúrbios gerados pela pista serão realizadas através de uma função degrau e uma função pulso com o objetivo de avaliar o desempenho de cada controlador. Após a implementação dos algoritmos de controle, foi possível verificar que o sistema de suspensão semiativo, frente às excitações propostas, apresentou um desempenho superior em relação ao conforto. Contudo, não tão significativas quanto ao do conforto, o sistema controlável também, comparativamente ao sistema passivo, apresentou melhoras no requisito dirigibilidade.Proven, the passive vehicle suspension system is a reliable and cost-effective solution solution for both chassis and wheel vibration levels reduction and chassis acceleration levels reduction. Although this system is widely used in vehicles, it has the disadvantage that its parameters can not be modified according to the variations generated by the track. This results in the use of the active suspension system, which allows the variation of the parameters of the suspension in real time, however, the use of this type of suspension requires a high level of energy for the correct operation of its actuators, resulting in the unfeasibility of some applications. To solve the disadvantages found for the passive and active suspension system, the semiactive suspension system arises, which combines the advantages of the active system, but with a lower energy consumption, consequently generating a reliable and economical solution control option to the problems of maneuverability and vehicular comfort. The present work intends to perform two evaluations, the first being the evaluation and comparison of a passive suspension system with the performance of four semi-active controllers (on/off, skyhook, groundhook and hybrid) and the second is to test the same controllers, but considering the dynamics of a magneticrheological damper through the LuGre model. These controllers will be applied to a nonlinear model of a quarter-car with two degrees of freedom, with its variables being estimated through a nonlinear state observer. The analysis for the comparison of the systems will be performed through numerical simulations using MatLab® software. The simulations of the disturbances generated by the track will be performed through a step function and a pulse function in order to evaluate the performance of each controller. After the implementation of the control algorithms, it was possible to verify that the system of semi-active suspension against the proposed excitations presented a superior performance in relation to comfort. However, not as significant as comfort, the controllable system alo compared to the passive system, presented improvements in the steerability requirement.
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Prokop, Aleš. "Odpružení kabiny traktoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229018.
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This Master's thesis deals with construction design suspension of tractor's cabin. At the very beginning there is an overview of different possibilities suspension from others producers. Afterwards there is my constructional working from selection variant of suspension to final project with all details. The another part of my thesis is strain-stress analysis of significant parts of construction and suggestion of comparing the method with the previous variant of suspension.
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Salis, José Inacio. "Método de apoio à tomada de decisão entre processos de manufatura e remanufatura de componentes dos sistemas de suspensão veiculares automotivos." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264949.
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Orientador: Jefferson de Oliveira GomesDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Este trabalho pretende avaliar se o processo de remanufatura de um determinado componente automotivo pode ser considerado como uma solução para algumas das principais questões relacionadas à sustentabilidade do respectivo processo de manufatura convencional. Como estudo de caso foi utilizado o processo de fabricação de um braço de controle de um sistema de suspensão veicular. A análise contextualizou as etapas de desenvolvimento de produtos de componentes automotivos, do seu ciclo de vida, da logística envolvida, sempre dentro de um ambiente sustentável. Em função do elevado número de parâmetros a serem avaliados e classificados em grau de representatividade ou contribuição, percebeu-se a necessidade de estudo de métodos para auxílio na tomada de decisão. Sendo assim, foram utilizados diferentes conceitos como a caracterização de Engenharia do Ciclo de Vida (ECV) e ferramentas inerentes para Análise do Ciclo de Vida (ACV) e determinação do Custo do Ciclo de Vida (CCV), além dos dois métodos multicriteriais diferentes, o Método de Função de Desdobramento da Qualidade ou Quality Function Deployment (QFD), assim como o Método de Análise Hierárquica ou Analytic Hierarchy Process (AHP). Os resultados foram apresentados por meio de um diagrama ternário, co-relacionando os critérios técnicos, econômicos e os impactos ambientais envolvidos
Abstract: This work wants to check if the remanufacturing process of a certain component automobile can be considered as a solution to some of the main issues related to the sustainability of its conventional manufacturing process. As a study case it was used to the analysis the manufacturing process of a control arm of the vehicle suspension system. Contextualized analysis stages of product development of automotive components, the life cycle of the same, the logistics involved, always within a sustainable environment. Due to the large number of parameters to be evaluated and classified as degree of representativeness or contribution, realized the need to study methods to aid in decision making. Therefore, different concepts were used to the characterization of Life Cycle Engineering (LCE) and associated tools for Life Cycle Analysis (LCA) and determining the Life Cycle Cost (LCC), in addition to the two different multicriterial methods, Method of Quality Function Deployment (QFD), as well as the Method of Analytic Hierarchy Process (AHP). The results were presented using a ternary diagram, co-relating the technical criteria, economic criteria and environmental impacts involved
Mestrado
Manufatura
Mestre em Engenharia Automobilistica
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Mingoto, Junior Carlos Roberto. "Método de medição de alinhamento de suspensão veicular não intrusivo baseado em visão computacional." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264577.
Full textAbstract:
Orientador: Paulo Roberto Gardel KurkaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: O presente projeto de pesquisa aplica técnicas de visão estereoscópica computacional no desenvolvimento da configuração de um equipamento de medição de ângulos de alinhamento de suspensão veicular, usando câmeras de vídeo de baixo custo. Atualmente, a maioria dos dispositivos de medição de ângulos de alinhamento de suspensão de veículos baseia-se no uso de componentes eletromecânicos, como pêndulos resistivos, inclinômetros capacitivos, dispositivos opto-mecânicos (espelhos e raio de luz monocromática de baixa intensidade). Com a sequência aqui estabelecida dos fundamentos algébricos e técnicas de visão computacional, realizam-se estudos de viabilidade científica e proposta de construção de um equipamento de verificação de ângulos de alinhamento veicular. São apresentados testes virtuais e reais, ilustrativos da potencialidade operacional do equipamento
Abstract: This research project uses stereoscopic computer vision techniques to develop a system to measure alignment angles of vehicular suspensions, using low cost cameras. Currently, most of the devices intended to measure vehicular suspension angles are based on the use of electromechanical components, such as resistive pendulums, capacitive inclinometers or opticmechanical devices (mirrors and projection of beams of monochromatic light of low intensity). Fundaments of linear algebra and computer vision techniques, lead to studies of feasibility and practical implementation of a system used to measure vehicular suspension alignment angles. Virtual and real measurements are carried out to illustrate the operative potential of such a system
Doutorado
Mecanica dos Sólidos e Projeto Mecanico
Doutor em Engenharia Mecânica
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Ganzarolli, Francisco. "Influência das frequências de ride no conforto e dirigibilidade veiculares na faixa linear de uso do veículo." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-05092012-073800/.
Full textAbstract:
O tema do conforto na automobilística é bastante extenso e possuidor de muitas interpretações. A ideia central deste trabalho é definir e direcionar alguns métricos para que, durante as fases de conceituação e desenvolvimento de um veículo, seja possível ter um direcional de definição de componentes e atributos veiculares de modo a facilitar o direcionamento dos atributos no programa veicular, e assim atingir suas necessidades. Como exemplo empregado, é empregado um veículo de plataforma tipo B em desenvolvimento por uma montadora, o qual teve as molas de suspensão definidas e rigidezes laterais de eixos com base em material técnico interno equivalente aos estudos apresentados neste trabalho. É adotada uma abordagem inicialmente empírica conforme os primeiros estudos de suspensões independentes realizados neste continente, depois o trabalho é complementado com exigências de normas especificas para vibrações (ISO2361, ISO5008, BS6055) de modo a caracterizar energia vibracional e a interpretação pelo ser humano. Porém como hoje em dia as suspensões automotivas são muito mais complexas, existem componentes específicos para as várias condições de solicitação, deste modo a análise é limitada a situações de ride (conforto) primário e handling (dirigibilidade) em situações de sublimite na faixa linear (cerca de 0,5 g). Como conclusão dos estudos, é possível ter em um veículo atributos de estabilidade sem necessariamente prejudicar o conforto, pois sendo definidos corretamente os componentes elásticos da dinâmica vertical para situações estacionárias e de ride primário, é definido seu equilíbrio estacionário e assim não é necessário comprometimento dos atributos de outros componentes para compensar alguma deficiência existente.The range of assumptions for ride comfort is considered very wide in the automotive world and they can assume lots of possible interpretations. The central idea in this work is define and manage some metrics that, during the concept and development phases of a vehicular program, be possible to follow a better direction for the attributes development and so reach the program targets. As the example in this work, a B platform typical vehicle is used and it is under development in a carmaker, its suspension springs and axle roll stiffness were setup with technical information similar to the ones presented in this work. The initial approach is empiric as occurred with the first independent suspension system studies in this continent and in the sequence, the work is complemented with standards for vibrational issues (ISO2361, ISO5008, BS6055), after this, finally how the vibrational energy is defined and perceived by human beings. The automotive suspensions of current days are very complex and there are lots of specific components to do a specific work, so the analysis are limited to primary ride and sub limit handling (up to 0,5 g). As conclusion, its possible setup a car that is comfortable and stable in the same time, since the elastic components for the vertical dynamics and steady state conditions are correctly set, so its correct balance is reached and no other components attributes are compromised to compensate any deficiency.
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Rojas, Rojas Oscar Ernesto 1987. "Implementação de um sistema de medição de ângulos para alinhamento de direção veicular usando visão computacional." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264532.
Full textAbstract:
Orientador: Paulo Roberto Gardel KurkaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Este trabalho tem como finalidade a implementação de um método de medição de ângulos de alinhamento de direção veicular, baseado em imagens estereoscópicas. São desenvolvidas soluções de processamento e análise de imagens, bem como a sua integração em um programa gerenciador da tarefa de medição dos ângulos. A implementação do programa de gerenciamento é feita utilizando os conceitos model-view-control (MVC) e programação orientada a objetos. Utilizam-se os pacotes de código livre framework C++ Qt®, Armadillo, OpenCV e DOxygen. São apresentados resultados de operação do sistema utilizando imagens virtuais e reais.
Abstract: The main objective of this work is the implementation of a measuring methodology to obtain the angles of alignment of the steering mechanism of a car, based on stereoscopic images. Solutions for image processing and analysis are proposed and implemented in the form of integrated operating software. Implementation of the software is done using the MVC (Model-View-Controller) and OOP (Object Oriented Programming) concepts. Free software packages are used, such as the Qt® C++ Framework, Armadillo, OpenCV and DOxygen. Results from the use of the operating software are presented, using virtual and real images.
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
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Sláma, Michal. "Řízení samoobslužných dveří a vzduchového pérování městského autobusu pomocí sběrnice CAN." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228814.
Full textAbstract:
The Diploma thesis is divided into 2 parts. The first one deals with the description of CAN-bus and the protocol of SAE J1939. The second part contains the practical solution to controlling of Passenger Operated Doors and controlling of Air Sprinte (ECAS). Both parts refer to contemporary (conventions/standards) and the whole task is solved in a new program environment KIBES-32.
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Hrudík, Jan. "Přední náprava vysokovýkonného sportovního vozu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-443475.
Full textAbstract:
Tato diplomová práce byla psána při studentské zahraniční stáži, pod záštitou Evropské Unie – program „ERASMUS Student Mobility for Placement“. Stáž byla absolvována mezi prosincem 2010 a květnem 2011 ve společnosti a.d.Tramontana, mající sídlo v Palau de Santa Eulália, Španělsko. Pro kompletní návrh podvozku a odpružení jakéhokoli vozidla je nezbytná znalost mnoha technických disciplín. Tato diplomová práce se zabývá dvěma z nich – odpružení a řízení. Nejprve je rozebrána teorie, na kterou se může navázat v praktické části práce. Velká pozornost byla věnována srozumitelnosti textu a názornosti obrázků, bez zbytečných detailů, avšak bez vynechání důležitého. Tuto práci je tedy možné užít jako prvního kroku před návrhem podvozku. V další části je popsáno, jak byla probraná teorie využita při návrhu řízení u skutečného vozu, přičemž největší pozornost je věnována Ackermannově teorii řízení a geometrii zabraňující samořízení při propružení. V závěrečných částech je pozornost věnována ukázce některých z každodenních činností v malosériové výrobě automobilů – jde o zjištění maximálně možného pohybu kola při propružení a proces výroby příčných trojúhelníkových ramen včetně návrhu jejich připevnění k šasi.
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Kat, Cor-Jacques. "Validated leaf spring suspension models." Thesis, 2012. http://hdl.handle.net/2263/24713.
Full textAbstract:
Mathematical and computer modelling have been playing an increasingly important role in the Computer Aided Engineering (CAE) process. Simulation offers great advantages in the development and analysis phase of products and offers a faster, better and more cost effective way than using physical prototypes alone. The ever increasing demand for new and improved products in the vehicle industry has decreased the time available for the development of new vehicles, but at the same time the demands on quality, reliability and mass that are set for the vehicle are becoming ever more stringent. These requirements have lead to the investigation of procedures and methodologies such as virtual prototyping that will reduce the development time of new vehicles without inhibiting the quality of the vehicle. In order to perform effective and reliable simulations in the CAE process, accurate simulation models of the vehicle and its associated systems, subsystems and components are required. In the vehicle dynamics context simulation models of the tyres, suspension, springs, damper, etc, are needed. This study will look at creating a validated model of a leaf spring suspension system used on commercial vehicles. The primary goal set for the model is to be able to predict the forces at the points where the suspension system is attached to the vehicle chassis as the model is to be used in full vehicle durability simulations. The component which will receive a considerable amount of attention in this study is the leaf spring. Leaf springs have been used in vehicle suspensions for many years. Even though leaf springs are frequently used in practice they still hold great challenges in creating accurate mathematical models. It is needless to say that an accurate model of a leaf spring is required if accurate full vehicle models are to be created. As all simulation models in this study are required to be validated against experimental measurements a thorough experimental characterisation of the suspension system of interest, as well as two different leaf springs, are performed. In order to measure the forces between the suspension attachment points and the chassis, two six component load cells were developed, calibrated, verified and validated. This study will primarily focus on the modelling of a multi-leaf spring as well as a parabolic leaf spring. The study starts with a literature study into the various existing modelling techniques for leaf springs. A novel leaf spring model, which is based on a macro modelling view point similar to that used for modelling material behaviour, is developed. One of the modelling techniques found in the literature, i.e. neural networks, is also used to model the leaf spring. The use of neural networks is applied and some of the challenges associated with the method are indicated. The accuracy and efficiency of the physics-based elasto-plastic leaf spring model and the non physics-based neural network model are compared. The modified percentage relative error metric is compared to two other quantitative validation metrics that were identified from the literature study. It is concluded that the modified percentage relative error has certain limitations but that it is able to give an accurate and representative account of the agreement/disagreement between two periodic signals around zero. The modified percentage relative error is used to obtain the accuracies of the elasto-plastic leaf spring models and the neural network model. Both models give good results with the neural network being almost 3 times more computationally efficient. The elasto-plastic leaf spring model, for the multi-leaf spring, is further extended to model the behaviour of a parabolic leaf spring. Qualitative validation using experimental data shows that the elasto-plastic leaf spring model is able to accurately predict the vertical behaviour of both the multi-leaf spring as well as the parabolic leaf spring. The elasto-plastic leaf spring model was also combined with a method that is able to capture the effect of changes in the spring stiffness due to changes in the loaded length. Quantitative validation shows that the method proposed for accounting for the change in stiffness due to changes in the loaded length is able to capture this characteristic of the physical leaf spring. Following a systematic modelling approach the elasto-plastic multi-leaf spring model is incorporated into a model of a simplified version of the physical suspension system. The qualitative validation results from this model show that the model is able to accurately predict the forces that are transmitted from the suspension system to the chassis. The models created in this study can be used in future work and, with the addition of more detail the models, can be extended to create a model of the complete suspension system.Thesis (PhD(Eng))--University of Pretoria, 2012.
Mechanical and Aeronautical Engineering
unrestricted
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Naude, Alwyn Francois. "Computer-aided simulation and optimisation of road vehicle suspension systems." Thesis, 2001. http://hdl.handle.net/2263/25692.
Full textAbstract:
Please read the abstract in the section, 00front, of this document Please note that the Compact disc with Vehsim2d (demonstration version) (Appendix B) is not includedThesis (PhD (Mechanical Engineering))--University of Pretoria, 2008.
Mechanical and Aeronautical Engineering
unrestricted
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Tims, Heath Eric. "Vehicle active suspension system sensor reduction." Thesis, 2005. http://hdl.handle.net/2152/2343.
Full text
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Berman, Robert. "Optimisation of a three spring and damper suspension." Thesis, 2016. http://hdl.handle.net/10539/22328.
Full textAbstract:
A dissertation submitted to the Faculty of Engineering and the Built Environment, University
of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of
Master of Science in Engineering.
Johannesburg 2016This investigation considers the influence of a three spring and damper suspension system (SDS) on overall vehicle performance. Three SDS systems are used in high performance winged racing cars to manage the effects of the aerodynamic forces. The aim of the investigation was to quantify and compare the performance of a three SDS system to that of a conventional two SDS system. The investigation was carried out on the Bailey Cars LMP2 race car. Physical track testing was conducted on Zwartkops Raceway to measure the vehicle’s performance, with further testing conducted on the vehicle’s tyres. A software model of the vehicle and tyres was then created in ADAMS/Car, with models for the conventional two SDS system, as well as the three SDS system. The ADAMS/Car model was then validated against the test data. A Design of Experiments approach was used to investigate the influence of the parameters in both the suspension models. The optimal set of suspension parameters, that maximised vehicle performance on Zwartkops Raceway, was then identified. The performance of the optimal suspension systems was then compared to quantify the effect of the three SDS system. It was found that the optimised three SDS system travelled 4.38 m less than the optimal two SDS in a 60 second simulation on Zwartkops Raceway. However, the three SDS was effectively able to isolate the pitch and roll stiffness of the vehicle. The optimal three SDS had a greater pitch stiffness and less roll stiffness than the two SDS. This is significant for winged vehicles where aerodynamic forces are highly sensitive to vehicle pitch, such as the Bailey Cars LMP2 race car, allowing for a soft wheel rate without sacrificing the pitch stiffness of the vehicle.
MT2017
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Fung, Justin. "Induction heat treated high strength suspension spring steels." 2006. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=442093&T=F.
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"Parametric analysis and semi-active control of automotive suspension systems." 2001. http://library.cuhk.edu.hk/record=b5890638.
Full textAbstract:
Lam Hiu Fung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references (leaves 106-111).
Abstracts in English and Chinese.
abstract --- p.i
摘要 --- p.iii
acknowledgements --- p.v
table of contents --- p.vi
list of figures --- p.viii
list of tables --- p.xi
Chapter 1 --- introduction --- p.1
Chapter 1.1 --- Controllable Suspension System --- p.1
Chapter 1.1.1 --- Automotive Suspension System --- p.2
Chapter 1.1.2 --- Controllable Devices --- p.4
Chapter 1.1.3 --- MR Fluid and Damper --- p.5
Chapter 1.2 --- Vibration Control --- p.5
Chapter 1.2.1 --- Active Control --- p.5
Chapter 1.2.2 --- Semi-active Control --- p.6
Chapter 1.2.3 --- Robust Control --- p.7
Chapter 1.3 --- Research Objective --- p.7
Chapter 1.4 --- Thesis Outline --- p.8
Chapter 2 --- PARAMETRIC STUDY OF SUSPENSION SYSTEMS --- p.9
Chapter 2.1 --- System Models and Transmissibility --- p.9
Chapter 2.1.1 --- Passive Suspension System --- p.10
Chapter 2.1.2 --- Skyhook Suspension System --- p.15
Chapter 2.1.3 --- Groundhook Suspension System --- p.24
Chapter 2.1.4 --- Hybrid Suspension System --- p.32
Chapter 2.1.5 --- Comparison among four suspension systems --- p.41
Chapter 2.2 --- Characteristics analysis --- p.45
Chapter 2.2.1 --- Passive Suspension System --- p.45
Chapter 2.2.2 --- Skyhook Suspension System --- p.47
Chapter 2.2.3 --- Groundhook Suspension System --- p.50
Chapter 2.2.4 --- Hybrid Suspension System --- p.52
Chapter 2.3 --- Stability --- p.54
Chapter 2.3.1 --- Stability in the Sense of Lyapunov for Suspension Systems --- p.54
Chapter 2.3.2 --- Stability for four Suspension Systems --- p.57
Chapter 2.4 --- Optimization --- p.63
Chapter 2.4.1 --- Single-Degree-of-Freedom Passive System --- p.63
Chapter 2.4.2 --- Two-Degree-of-Freedom Passive System --- p.65
Chapter 2.4.3 --- Hybrid Suspension System --- p.67
Chapter 3 --- SUSPENSION SYSTEM WITH VIBRATION CONTROLLER --- p.71
Chapter 3.1 --- Two-Degree-of-Freedom Quarter Car Model --- p.71
Chapter 3.2 --- MR Damper --- p.73
Chapter 3.3 --- Vibration Controller --- p.75
Chapter 3.3.1 --- System Controller: Sliding Mode Control --- p.76
Chapter 3.3.2 --- Damper Controller: Continuous-state Control --- p.83
Chapter 4 --- SIMULATION RESULTS --- p.85
Chapter 4.1 --- Transmissibility analysis --- p.86
Chapter 4.2 --- Simulation --- p.89
Chapter 4.2.1 --- Test by Bump Excitation --- p.89
Chapter 4.2.2 --- Test by Random Excitation (White noise) --- p.91
Chapter 4.2.3 --- Test by Road Elevation Profile --- p.95
Chapter 5 --- CONCLUSIONS AND FUTURE WORK --- p.99
Chapter 5.1 --- Summary --- p.99
Chapter 5.2 --- Future Work and Further Development --- p.100
Chapter 5.2.1 --- Parametric study of the MR suspension system --- p.100
Chapter 5.2.2 --- Systematic method for selecting control gains --- p.101
Chapter 5.2.3 --- New control algorithm --- p.101
Chapter 5.2.4 --- Extension to half and full car models --- p.102
Chapter 5.2.5 --- System implementation --- p.102
appendix
Chapter A.1 --- Additional information of the transmissibility of unsprung mass.… --- p.103
Chapter A.2 --- Additional figures of the random excitation test: --- p.104
BIBLIOGRAPHY --- p.106
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"Vibration control of a suspension system via a magnetorheological fluid damper." 2000. http://library.cuhk.edu.hk/record=b5895800.
Full textAbstract:
by Lai Chun Yu.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references (leaves 75-79).
Abstracts in English and Chinese.
LIST OF FIGURES --- p.vi
LIST OF TABLES --- p.ix
Chapter 1 --- INTRODUCTION --- p.1
Chapter 1.1 --- Background --- p.1
Chapter 1.1.1 --- Vibration Control of Suspension Systems --- p.1
Chapter 1.1.2 --- Semi-active Devices --- p.3
Chapter 1.2 --- Literature Review --- p.5
Chapter 1.2.1 --- MR Fluid and Damper --- p.5
Chapter 1.2.2 --- Vibration Control --- p.6
Chapter 1.2.3 --- Robust Control --- p.8
Chapter 1.3 --- Research Objective --- p.9
Chapter 1.4 --- Organization of the Thesis --- p.9
Chapter 2 --- MR DAMPER BEHAVIOR AND MODELING --- p.11
Chapter 2.1 --- MR Damper --- p.12
Chapter 2.2 --- Mathematical Model --- p.13
Chapter 2.3 --- Experimental Setup --- p.15
Chapter 2.4 --- Damper Characteristics --- p.18
Chapter 2.5 --- Comparison Between Model with Experimental Data --- p.25
Chapter 2.5.1 --- Graphical Study --- p.26
Chapter 2.5.2 --- Quantitative Study --- p.26
Chapter 2.5.3 --- Other Input Tests --- p.27
Chapter 3 --- SEMI-ACTIVE VIBRATION CONTROL --- p.33
Chapter 3.1 --- Dynamic Modelling of Suspension Systems --- p.33
Chapter 3.2 --- Single-degree-of-freedom (SDOF) Passive Suspension System --- p.34
Chapter 3.2.1 --- Viscous Damper --- p.34
Chapter 3.2.2 --- MR Damper --- p.37
Chapter 3.3 --- Single-degree-of-freedom (SDOF) Semi-active Suspension System --- p.41
Chapter 3.3.1 --- Ideal Skyhook Control --- p.41
Chapter 3.3.2 --- Semi-active Skyhook Control --- p.44
Chapter 3.4 --- Semi-active Robust Control Development --- p.46
Chapter 3.5 --- Sliding Mode Control --- p.47
Chapter 3.6 --- Semi-active Damper Control --- p.51
Chapter 3.6.1 --- On-off Control --- p.52
Chapter 3.6.2 --- Continuous-state Control --- p.53
Chapter 3.6.3 --- Comparison Between On-off and Continuous-state Controller --- p.54
Chapter 4 --- SIMULATION STUDIES --- p.57
Chapter 4.1 --- Transmissibility --- p.57
Chapter 4.2 --- Different Base Excitations --- p.59
Chapter 4.2.1 --- Bump Input --- p.60
Chapter 4.2.2 --- Random Input --- p.62
Chapter 5 --- CONCLUSION --- p.67
Chapter 5.1 --- Summary --- p.67
Chapter 5.2 --- Future Work --- p.68
APPENDIX --- p.69
Chapter A.1 --- Semi-active Control with MR Damper ´ؤ Main Program Listing --- p.69
Chapter A.2 --- Sub-program Listing (Dynamic System) --- p.70
Chapter A.3 --- Sub-program Listing (Sliding Mode Controller) --- p.73
Chapter A.4 --- Sub-program Listing (MR Damper Model) --- p.73
BIBLIOGRAPHY --- p.75
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Strydom, Anria. "Controllable suspension design using magnetorheological fluid." Diss., 2013. http://hdl.handle.net/2263/32545.
Full textAbstract:
The purpose of this study is to mitigate the compromise between ride comfort and handling of a
small single seat off-road vehicle known as a Baja. This has been achieved by semi-active control of
the suspension system containing controllable magnetorheological (MR) dampers and passive
hydro-pneumatic spring-damper units.
MR fluid is a viscous fluid whose rheological properties depend on the strength of the magnetic
field surrounding the fluid, and typically consists of iron particles suspended in silicone oil. When a
magnetic field is applied to the fluid, the iron particles become aligned and change the effective
viscosity of the fluid. The use of MR fluid in dampers provides variable damping that can be changed
quickly by controlling the intensity of the magnetic field around the fluid. Various benefits associated
with the use of MR dampers have led to their widespread implementation in automotive engineering.
Many studies on conventional vehicles in the existing literature have demonstrated the conflicting
suspension requirements for favourable ride comfort and handling. Generally, soft springs with low
damping are ideal for improved ride comfort, while stiff springs with high damping are required for
enhanced handling. This has resulted in the development of passive suspension systems that provide
either an enhanced ride quality or good drivability, often targeting one at the expense of the other.
The test vehicle used for this study is distinct in many ways with multiple characteristics that are
not commonly observed in the existing literature. For instance, the absence of a differential in the test
vehicle driveline causes drivability issues that are aggravated by increased damping.
The majority of existing MR damper models in the literature are developed for uniform excitation
and re-characterisation of model parameters is required for changes in input conditions. Although
recursive models are more accurate and applicable to a wider range of input conditions, these models
require measured force feedback which may not always be available due to limitations such as packaging constraints. These constraints required the development of alternative MR damper models
that can be used to prescribe the current input to the damper.
In this study parametric, nonparametric and recursive MR damper models have been developed
and evaluated in terms of accuracy, invertibility and applicability to random excitation. The
MR damper is used in parallel with passive damping as a certain amount of passive damping is always
present in suspension systems due to friction and elastomeric parts.
Most of the existing studies on suspension systems have been performed using linear two degree
of freedom vehicle models that are constrained to specific conditions. Usually these models are
implemented without an indication of the ability of these models to accurately represent the vehicles
that these studies are intended for.
For this study, a nonlinear, three-dimensional, 12 degrees of freedom vehicle model has been
developed to represent the test vehicle. This model is validated against experimental results for ride
comfort and handling. The MR damper models are combined with the model of the test vehicle, and
used in ride comfort and handling simulations at various levels of passive damping and control gains
in order to assess the potential impact of suspension control on the ride quality and drivability of the
test vehicle.
Simulation results show that lower passive damping levels can significantly improve the ride
comfort as well as the handling characteristics of the test vehicle. Furthermore, it is observed that
additional improvements that may be obtained by the implementation of continuous damping control
may not be justifiable due to the associated cost and complexity.Dissertation (MEng)--University of Pretoria, 2013.
Mechanical and Aeronautical Engineering
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Janse, van Rensburg Neil. "Time delay in a semi-active damper." Diss., 2001. http://hdl.handle.net/2263/26012.
Full textAbstract:
In this study the feasibility of two mathematical models of the dynamics of a hydraulic bypass valve used on semi-active suspension systems for heavy vehicles is investigated. It is envisaged that similar models will eventually be incorporated into a full vehicle, three dimensional simulation study. The valve system contains an electro-hydraulic pilot valve circuit, a logic element, a damper and four check valves in a rectifier configuration. Models were compiled from first principles in the MATLAB environment and with the commercial fluid power simulation software, AMESim. The numerical methods used in the MATLAB model were found to be incapable of solving the stiff, nonlinear and discontinuous governing equations efficiently, while AMESim is very capable of handling detailed and complex fluid power models. Experimental work was conducted to determine certain steady state model parameters and to obtain dynamic performance data with which to validate model integrity. Several external factors influenced the valve behaviour during experiments making data extraction challenging. Simple first order assumptions accounting for the external influences on the valve therefore had to be included in the models. If this is done the basic dynamic behaviour of the valve system is matched well by the models. In general, the number of unknown parameters associated with fluid power systems accounted for the largest portion of the error between the simulated and measured response. The model as developed proved the possibility of creating highly accurate models but also indicated the amount of effort needed for their compilation.Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007.
Mechanical and Aeronautical Engineering
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