Дисертації з теми "Pneumatic suspension system"

This study is focused on modifying an existing solenoid valve based semi-active hydropneumatic spring-damper system using Magneto-Rheological (MR) fluid. The MR fluid's effective viscosity can be altered by application of a magnetic field. Therefore, using a magnetic/ MR valve makes it possible to change the state of the system by simply changing the applied magnetic field. A prototype MR valve was developed to determine whether a unit small enough for installation was possible. This prototype valve was designed from first principles and properties such as pressure drop over the valve (damping) and flow blocking (for switching between spring characteristics) were measured. The measured pressure drop over the valve was higher than what was design for which was due to an incorrect assumption for the viscosity of the thixotropic MR Fluid. The flow blocking ability of the valve was determined by constant force tests. Results showed that the valve could virtually block the flow of fluid for approximately a quarter of the vehicles weight. With the second prototype, the valve design and magnetic circuit design were improved. Two valves were constructed and implemented on a prototype suspension system. The damping characteristics of the system were lower than expected, however they can be improved by changing the valve geometry. The base spring characteristics are acceptable, however the higher spring characteristics fail when a high force is exerted on the strut that exceeds the valves flow blocking capability. The response time of the valve is not yet sufficient to make the system viable for real world implementation, especially under extreme conditions that can change more rapidly than the current valves.
Dissertation (MEng)--University of Pretoria, 2015.
Mechanical and Aeronautical Engineering
MEng
Unrestricted

This report details the work done in a master thesis project. The project was conducted at the Brake Performance Department at Scania CV AB. The project involves the development of a numerical model (in Matlab) that calculates and predicts air consumption in a truck under different drive cycles. The report first details tests and experiments done so as to acquire the necessary information for the development of the model. The report then presents the model that was created and delves into tests that were conducted for its validation. A model is created that allows the user to select different component combinations on the trucks along with different loading scenarios and drive cycles. Finally the model is used to evaluate air consumption in trucks during particularly strenuous cycles. The model developed is found to be reliable and accurate to with 7% with regard to amount of air consumed. With its help, several recommendations on how air consumption in commercial vehicles can be improved are made. The best components’ combination is also found and presented.
I denna rapport beskrivs ett examensarbete som genomfördes på bromsavdelningen på Scania CV AB. Projektet innefattar utveckling av en numerisk modell (i Matlab) som beräknar och förutspår luftförbrukningen i en lastbil under olika körcykler. I rapporten beskrivs det tester och experiment som gjordes för att ta fram nödvändiga uppgifter för utvecklingen av modellen. Sedan presenteras modellen som skapades och alla valideringstester som genomfördes. Modellen är gjord så att användaren kan kombinera olika komponentkombinationer för lastbilar med olika lastningskonfigurationer och körcykler. Slutligen används modellen för att utvärdera luftförbrukningen i lastbilar under särskilt ansträngande körcykler. Den utvecklade modellen visade sig vara pålitlig och korrekt med en felmarginal på 7% med avseende på mängden luft som konsumeras. Med dess hjälp kunde flera rekommendationer ges om hur luftförbrukningen i kommersiella fordon kan förbättras. De bästa komponentkombinationerna hittades också och presenteras i denna rapport

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019 р. Дисертація присвячена поліпшенню експлуатаційних властивостей колісного трактора в агрегаті з напівпричепом при русі на транспортних режимах за рахунок обладнання переднього моста комбінованою пневморесорною підвіскою та визначення її раціональних параметрів. Для вирішення поставленої задачі в роботі проаналізовані сучасні тенденції використання колісних тракторів під час перевезення вантажів, котрі є основною сільськогосподарською продукцією, а також продукцією призначеною для забезпечення виробничих процесів сільськогосподарських підприємств. Визначено основні вимоги, які висуваються до конструкції тракторів, які застосовуються в якості транспорту в сільськогосподарській галузі. Розглянуто тенденції розвитку конструкцій систем підресорювання колісних тракторів з урахуванням виконання вантажоперевезень із підвищеними транспортними швидкостями. Виконано аналіз методів і конструктивних засобів поліпшення плавності ходу й зниження динамічної навантаженості ходових систем. Визначено експлуатаційні вимоги, які висуваються до підвісок колісних тракторів. А також встановлені шляхи поліпшення показників плавності ходу на основі вдосконалення систем підресорювання. У рамках дослідження складена узагальнена математична модель поздовжньо-кутових, вертикальних і поздовжніх коливань машино-тракторного агрегату на базі колісного трактора з напівпричепом, яка дозволяє досліджувати плавність ходу й динамічну навантаженість ходової системи. Складена математична модель доповнена математичними моделями пневматичної шини, пневматичного гумово-кордового пружного елемента й тяглово-зчіпного пристрою. Це дозволяє врахувати наявність демпфірування в пневматичній системі комбінованої пневморесорної підвіски, найбільш повно оцінити вплив нелінійності пружних і дисипативних характеристик шини та пневмобалона, а так само наявність зазору в тяглово-зчіпному пристрої на показники плавності ходу й динамічну навантаженість ходової системи колісного трактора. Для найбільш повної оцінки плавності ходу й динамічної навантаженості ходової системи колісного трактора обладнаного різними типами систем підресорювання математична модель реалізована в детермінованій постановці з мікропрофілем, який відповідає різним дорожнім покриттям. Для зниження динамічної навантаженості ходової системи й поліпшення параметрів плавності ходу машино-тракторного агрегату на базі колісного трактора та напівпричепа, була розроблена комбінована пневморесорна підвіска, яка встановлена на передній міст трактора. При розробці регульованої пневморесорної підвіски використовувалися серійні вузли та деталі підвіски з листовими металевими ресорами. Пневморесорна підвіска розміщена в габаритних розмірах серійної підвіски, та складається з листових металевих ресор й двохсекційних пневмобалонів з додатковими повітряними резервуарами. Для збільшення демпфування в підвісці, в трубопроводі на вході до додаткових резервуарів було встановлено дроселі. При зростанні статичного навантаження на передній міст регулятор положення рами за допомогою клапану автоматично забезпечує надходження стисненого повітря до пневмобалонів по трубопроводах, а при її зменшені – випуск повітря до атмосфери. Таким чином забезпечується підтримання постійного зазору між пружним упором стискання та переднім мостом. З метою найбільш повної оцінки властивості конструкції розробленої пневморесорної підвіски та її досконалості при використанні трактора проведено експериментальні дослідження машино-тракторного агрегату в різних експлуатаційних умовах. Результати отримані під час проведення натурного експерименту дали можливість підтвердити достовірність теоретичних досліджень, та оцінити адекватність математичної моделі використовуваної для вивчення взаємозв’язків між параметрами конструкції підвіски та її експлуатаційними показниками. Також була запропонована методика проведення експериментальних досліджень по визначенню демпфування в пневматичній системі комбінованої пневморесорної підвіски, методика визначення параметрів плавності ходу та динамічної навантаженості ходової системи машино-тракторного агрегату при виконанні транспортних робіт. Під час проведення натурного експерименту визначено ступень дисипації в пневморесорній підвісці при різних прохідних перетинах дроселя, а також при різних об’ємах додаткових резервуарів, та визначено раціональний діаметр перехідного перетину дроселя. Проведена оцінка плавності ходу та динамічної навантаженості ходової системи машино-тракторного агрегату обладнаного серійною ресорною підвіскою, комбінованою пневморесорною підвіскою з гідравлічними амортизаторами та без гідравлічних амортизаторів, при русі трактора по дорозі з асфальтним і ґрунтовим покриттям, а саме проведена порівняльна оцінка пневматичного й гідравлічного демпфірування, порівняльна оцінка плавності ходу трактора із серійною та пневморесорними підвісками, шляхом визначення параметрів низькочастотних коливань у характерних точках трактора. Також визначена динамічна навантаженість ходової системи трактора оснащеного різними системами підресорювання. Для вимірів результатів експерименту, а саме для реєстрації параметрів низькочастотних коливань використовувався вимірювальний комплекс, що складається з вібровимірювальної апаратури. Для реєстрації динамічного навантаження передніх й задніх коліс трактора використовувалися тензодатчики, наклеєні на рукавах мостів, при цьому тензометричні датчики збиралися в тензометричні мости сигнал з котрих надходив до фіксуючої апаратури. На підставі аналізу отриманих даних встановлено, що застосування комбінованої пневморесорної підвіски з гідравлічними амортизаторами в порівнянні із серійною ресорною підвіскою дозволяє знизити величини середньоквадратичних прискорень у характерних точках трактора й знизити динамічне навантаження, що діє на колеса машино-тракторного агрегату. Проведено теоретичні дослідження, які дозволили дати об'єктивну оцінку впливу типу підвіски та її конструктивних параметрів на плавність ходу й динамічну навантаженість ходової системи колісного трактора. Визначено шляхи вдосконалення системи підресорювання й розроблені рекомендації з вибору раціональних параметрів підвіски. На підставі аналізу проведених експериментальних досліджень динамічних процесів, які виникають під час руху колісного трактора в агрегаті з напівпричепом, встановлено, що результати теоретичних розрахунків якісно й кількісно відображають характер зміни та рівень показників плавності ходу й динамічної навантаженості ходової системи машино-тракторного агрегату. Також підтверджені рекомендації щодо обраних раціональних параметрів системи підресорювання переднього мосту колісного трактора. Згідно рекомендацій найкращі показники плавності ходу та динамічної навантаженості ходової системи колісного трактора з шарнірно-зчленованою рамою на транспортних роботах досягаються при наступних обґрунтованих основних конструктивних параметрах комбінованої пневморесорної підвіски: діаметр прохідного перетину дроселя 9 мм, що забезпечує максимальне повітряне демпфірування в пневматичній системі та коефіцієнт загасання ψ=0,21; об’єм додаткових резервуарів Vd =40·10ˉ³ м³ на сторону; тиск у пневматичній системі 0,27 МПа; величина коефіцієнта загасання гідравлічного амортизатора ψа=0,21.
The dissertation for obtaining a scientific degree of Candidate of Science (Technology) on the specialty 05.22.02 – automobiles and tractors. –National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The dissertation is devoted to improving the operational properties of a wheeled tractor in an aggregate with a semi-trailer during the driving in transport modes, due to the equipment of the front axle with a combined air spring suspension and determining its rational parameters. To solve this problem we have analyzed the current tendencies in the application of wheeled tractors in the transportation of the main agricultural products, as well as products intended to support the production processes of agricultural enterprises. The basic requirements for the construction of tractors used as a transport in the agricultural sector have been defined. The tendencies of development of designs of suspension systems of wheel tractors with consideration of performance of cargo transportation with the increased transport speeds have been considered. The analysis of methods and constructive approaches of improving the smoothness of the course and reducing the dynamic load of the running systems have been performed. The operational requirements for suspension wheeled tractors have been defined. There are also ways to improve the smoothness of the course based on the improvement of the suspension systems. In the framework of the study a generalized mathematical model of longitudinal-angular, vertical and longitudinal oscillations of a machine-tractor unit based on a wheeled tractor with a semi-trailer, which allows to investigate the smooth running and the dynamic load of the running system, is drawn up. The mathematical model is completed with mathematical models of pneumatic tire, pneumatic rubber-cord elastic element and traction coupling. This allows to take into account the presence of damping in the pneumatic system of the combined pneumatic spring suspension, to fully assess the influence of nonlinearity of the elastic and dissipative characteristics of the tire and the pneumatic cylinder, as well as the presence of a gap in the traction-coupling device on the trajectory of smooth running and dynamic load. For the most completed evaluation of the smooth running and dynamic loading of the running system of a wheeled tractor equipped with different types of suspension systems, a mathematical model is implemented in a deterministic formulation with micro-profiles corresponding to different road surfaces. To reduce the dynamic load of the running system and improve the parameters of the smooth running of the machine-tractor unit based on the wheeled tractor and semi-trailer, a combined pneumatic spring suspension have been developed, which was mounted on the front axle of the tractor. Developing the adjustable pneumatic spring suspension we used serial units and suspension parts with sheet metal springs. The pneumatic spring suspension is housed in the overall dimensions of the serial suspension, and consists of sheet metal springs and two-section pneumatic cylinders with additional air tanks. In order to increase the damping in the suspension, throttles were installed in the pipeline at the inlet to the additional tanks. As the static load on the front axle increases, the regulator of the frame position by means of a valve automatically ensures the supply of compressed air to the air cylinders through the pipelines, and with its reduction – the release of air to the atmosphere. This ensures that there is a constant gap between the elastic compression stop and the front axle. With the purpose of the most complete evaluation of the design properties of the developed pneumatic spring suspension and its perfection when using the tractor, experimental studies of the machine-tractor unit under different operating conditions have been performed. The results obtained during the full-scale experiment made it possible to confirm the validity of theoretical studies and to evaluate the adequacy of the mathematical model used to study the relationship between the suspension structure parameters and its performance. Also, a method of conducting experimental studies to determine the damping in the pneumatic system of the combined pneumatic spring suspension, the method of determining the parameters of smooth running and the dynamic load of the running system of the machine-tractor unit in the performance of transport works was also proposed. During the full-scale experiment, the degree of dissipation in the pneumatic spring suspension was determined at different throttle cross-sections, as well as at different volumes of additional tanks, and the rational diameter of the throttle cross-section was determined. The estimation of the smoothness of the course and the dynamic loading of the running system of the machine-tractor unit equipped with a serial spring suspension, combined pneumatic spring suspension with hydraulic shock absorbers and without hydraulic shock absorbers, when driving the tractor on the road with asphalt comparative estimation of the smooth running of the tractor with serial and pneumatic spring suspensions, by determining the parameters of low-frequency oscillations at the characteristic points of the tractor. The dynamic loading of the running gear of the tractor equipped with various suspension systems is also determined. To estimate the results of the experiment, namely to record the parameters of low-frequency oscillations, a measuring complex consisting of vibration measuring equipment was used. To register the dynamic load of the front and rear wheels of the tractor were used strain gauges glued to the sleeves of the bridges, while the strain gauge sensors were collected in the strain gauge bridges signal from which came to the fixing equipment. Being based on the analysis of the obtained data, it has been found out that the application of a combined pneumatic spring suspension with hydraulic shock absorbers in comparison with the serial spring suspension allows to reduce the magnitude of the rms acceleration at the characteristic points of the tractor and to reduce the dynamic load acting on the wheels of the machine-tractor. Theoretical researches allowed to give an objective estimation of influence of a type of a suspension bracket and its design parameters on smoothness of a course and dynamic loading of a running system of a wheel tractor are carried out. Ways to improve the suspension system were identified and recommendations were made for choosing rational suspension parameters. Based on the analysis of the experimental studies of the dynamic processes that occur during the movement of a wheeled tractor in a semi-trailer unit, it is established that the results of theoretical calculations qualitatively and quantitatively reflect the nature of the change and the level of smoothness and dynamic load of the running gear of the machine-tractor system. Recommendations for the selected rational parameters of the front axle suspension system of the wheeled tractor have been also confirmed. According to the recommendations, the best performance of smooth running and dynamic loading of the running system of the wheeled tractor with the articulated frame on the transport works are achieved with the following substantiated basic design parameters of the combined pneumatic spring suspension: diameter of the throttle cross-section 9 mm, which provides the maximum air damping in the pneumatic system and attenuation coefficient ψ=0,21; volume of additional tanks Vd =40·10ˉ³ m³ per side; pressure in the pneumatic system 0,27 MPa; the value of the damping coefficient of the hydraulic shock absorber ψа=0,21.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019 р. Дисертація присвячена поліпшенню експлуатаційних властивостей колісного трактора в агрегаті з напівпричепом при русі на транспортних режимах за рахунок обладнання переднього моста комбінованою пневморесорною підвіскою та визначення її раціональних параметрів. Складено узагальнену математичну модель поздовжньо-кутових, вертикальних та поздовжніх коливань машино-тракторного агрегату на базі колісного трактора в агрегаті з напівпричепом, яка дає змогу дослідити плавність ходу та динамічну навантаженість ходової системи з урахуванням нелінійності пружних та дисипативних характеристик підвіски, а також конструктивних характеристик тягово-зчіпного пристрою. Виконано теоретичні дослідження, котрі дозволили дати об'єктивну оцінку впливу типу підвіски та її конструктивних параметрів на плавність ходу й динамічну навантаженість ходової системи колісного трактора. Визначено шляхи вдосконалювання системи підресорювання та її раціональні параметри. На основі експериментальних досліджень підтверджено достовірність математичної моделі руху машино-тракторного агрегату на транспортних швидкостях, та підтверджено рекомендації щодо вибраних раціональних параметрів системи підресорювання переднього моста колісного трактора.
The dissertation for obtaining a scientific degree of Candidate of Science (Technology) on the specialty 05.22.02 – automobiles and tractors. –National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The dissertation is devoted to improving the operational properties of a wheeled tractor in an aggregate with a semi-trailer when driving in transport modes, due to the equipment of the front axle with a combined air spring suspension and determining its rational parameters. A generalized mathematical model of the longitudinal-angular, vertical and longitudinal oscillations of a machine-tractor unit based on a wheeled tractor in an aggregate with a semi-trailer has been compiled, which allows us to study the smoothness and dynamic loading of the running system with taking into account the nonlinearity of the elastic and dissipative characteristics of the suspension, as well as the structural characteristics of the towing device. Theoretical studies have been carried out, which made it possible to give an objective assessment of the influence of the type of suspension and its design parameters on the smoothness and dynamic loading of the wheeled tractor running system. Ways to improve the suspension system are identified and recommendations for the selection of rational suspension parameters are developed. Based on experimental studies, the reliability of the mathematical model of the movement of a ma-chine-tractor unit at transport speeds is confirmed. The recommendations regarding the selected rational parameters of the suspension system of the front axle of the wheeled tractor are also confirmed.

This thesis describes a programme of work which has been undertaken with the objective of obtaining data relating to the performance of on-line mass flow rate meters as applied to pulverised coal injection systems. Such injection systems are utilised widely in power generation, cement and steel manufacture. A technology review was carried out, incorporating an extensive literature survey. This review precipitated the conclusion that a number of techniques have been proposed, which may be applicable to the measurement under investigation. However, very little experimental verification of sensing systems based on these techniques had been undertaken. A test facility, suitable for such verification was therefore developed and an extensive programme of tests were carried out, of a sensing system based on an electrostatic technique. The development of a mathematical model of the sensor operation has also been undertaken, in an attempt to explain some of the more unusual aspects of the experimental results. The overall conclusion is that some aspects of the measurement can be achieved without major difficulties, whilst problems have yet to be resolved in respect of other aspects of the measurement system. The principle of the measurement system is such that the independent measurement of average particle velocity and suspension density are required in order to measure mass flow rate. The measurement of average particle velocity was shown to be achievable by either of two techniques, whilst the measurement of suspension density proved more problematic. Recommendations for further work, aimed at addressing these remaining aspects are detailed.

Tato práce se se zabývá návrhem kinematiky zavěšení kol obou náprav. Na základě analýz jízdních dat, multi-body simulací v softwaru Adams Car, simulací v Matlabu a analytických kalkulací v Mathcadu, je navržena řada změn s cílem zlepšit jízdní vlastnosti vozu Formule student, tyto změny jsou následně implementovány do CAD modelu vozu. Jednotlivé změny kinematiky náprav jsou provedeny na základě analýzy konkrétního problému, který se snaží řešit. Jednou z problematik je zástavbová náročnost systému odpružení a zavěšení zadních kol, zde je cílem snížit hmotnost, výšku těžiště a moment setrvačnosti. Další problematikou je geometrie předního kola, kde je cílem zlepšit využití pneumatik a snížit síly v řízení. Dále se práce zabývá simulacemi elastokinematiky zadní nápravy, součástí je také návrh měřícího zařízení. V poslední části je zkoumán vliv provedených změn i elastokinematiky na jízdní dynamiku vozu v ustálených stavech za pomocí MM metody simulované s modelem celého vozu v Adams Car a zpracované v Matlabu.

碩士
大葉大學
機械工程研究所碩士在職專班
96
A heavy off-road land vehicle’s safety, ride, and handling are the mainly consideration when exercised in cross-country road. Since the traditional mechanical suspension system need to maintain controllable of vehicle, the driver and passengers have to endure the intense impact from the road. On the other hand, the pursuit of ride will be ignored by safety and handling. To explore a good suspension system installation is very important. This paper adopted hydro-pneumatic suspension system and used double A-arm suspension design institutions to discuss heavy-duty wheeled vehicle. And, this paper utilized Automatic Dynamic of Mechanical Systems (ADAMS), a kind of software for multi-body dynamics, to establish a two-degree-of-freedom (2-DOF) quarter-car dynamic model. Then, input a different frequency stability sine wave to carry observation of the quality of dynamic response, to examine the vertical movement and the frequency domain performance of the hydro-pneumatic suspension system, and to explore the human body vibration on the impact of comfort. Re-use suspension durability testing platform for dynamic experiments, comparison of the vertical movement and acceleration between the actual hydro-pneumatic suspension system components and construction model. Finally, implementation of decompression tests for the nonlinear air-spring of the hydro-pneumatic suspension system, to understand suspension system performance by the pressure of air- spring changes impact. The results showed that the heavy-duty wheeled vehicle using hydro-pneumatic suspension system can reduce the components occupy space of vehicles and perform a more stable condition. It can achieve good results in ride evaluation. In addition, the experimental verification of results of the hydro-pneumatic suspension system ADAMS model is very close to the actual status. Compared with the traditional coil-spring suspension system, the hydro-pneumatic suspension system can reduce the pressure of air-spring to improve riding comfort. The hydro-pneumatic suspension system in this research can be applied in the heavy type vehicles, and it can assemble with semi-active or active control components to increase the suspension performance. The hydro-pneumatic suspension system ADAMS model can expand to whole vehicle modeling, and further forecast the performance of ride comfort and handling.

碩士
國立臺灣大學
機械工程學研究所
103
This thesis studies the dynamic and structural analysis of the hydro-pneumatic suspension of the wheeled heavy vehicle, and discussion on the performance of the new hydro-pneumatic shock absorber and the structural strength and rigidity of new design components of the suspension. From literature review, this study summarizes conventional methods in research of the suspension system, and chooses suitable simulation methods for research. In addition to the rigid body model commonly used in the literature, this study creates a flexible body model that is closer to real suspension components to obtain more realistic results, and discusses on the differences in the results between rigid body model and flexible body model. This thesis uses finite element software: Abaqus to create rigid body model simulation analysis, and uses multi-body dynamic software: ADAMS to do the same simulation, and compare results between Abaqus and ADAMS. Finally, this study uses Abaqus to create the flexible body model to obtain more realistic results. The simulation results show that dynamic results between Abaqus and ADAMS are consistent, and it means the rigid model and its results are reasonable. From results of the flexible body model, it shows the newly designed hydro-pneumatic shock absorber doesn’t meet requirements. And the structural strength and rigidity of new design components of the suspension are enough. Finally, by comparing the results between rigid body model and flexible body model, this thesis presents a more efficient method of dynamic and structural analysis, and uses this method to simulate suspension responses with different parameters to provide the basis for improving performances of the shock absorber.

碩士
輔仁大學
電機工程學系碩士班
104
This thesis firstly proposed a pneumatic road actuation system based on fuzzy logic control technique for the developed suspension test bench. The road actuation system can provide the simulated road profile for the analysis in the vehicle suspension control system. Further, the neural network (NN) is applied to learn the control parameters of fuzzy logic controller in different road surface conditions. Due to high nonlinearity and uncertainty of the utilized pneumatic actuation system in the developed road surface simulator, the genetic algorithm (GA) optimization is adopted to assist NN to gain the optimized control parameters for the fuzzy controller. In the second part of thesis, LQR-based optimal controller is designed for the pneumatic-muscle active vehicle suspension system against the road disturbance. Besides, the road profile is employed into the feedforward compensation with the vehicle body control loop so that the suspension control performance can be enhanced. Finally, the experimental results under different road conditions are given to verify the superior performance of the active suspension controller using pneumatic muscle actuators.

碩士
龍華科技大學
機械工程系碩士班
104
This thesis aims at the controller design for the pneumatic muscle activate vehicle suspension system in order to provide better riding comfort and driving controllability. Since the pneumatic muscle activate vehicle suspension system is highly nonlinear and time-dependent, it is difficult to build an accurate mathematical model for the system dynamics of the controller design. Therefore, this thesis combines a finite Fourier series approximation system dynamic mathematical model with adaptive control, sliding mode control, and the H_∞ tracking technique to design an adaptive sliding mode controller for a pneumatic muscle activate vehicle suspension system. The controller consists of Fourier series and an adaptive control approximation system dynamic mathematical model, where the sliding mode controller design requires the constraints of the system’s mathematics model. In addition, the H_∞ tracking technique is applied to compensate the approximation error and system external interference, in order to mitigate the discontinuous jump cut caused by the sliding mode controller, and the updated rules of the controller parameters are deduced from the Lyapunov stability criteria, thus, guaranteeing the stability of the controlled process of the system, improving the control effect, and reducing the difficulty level of actual control. Furthermore, in order to enhance the vibration suppression and vibration reduction of the system, this thesis uses the grey forecast algorithm to predict the next system error as the controller input. The experiments prove that the proposed controller with the grey forecast algorithm performs better vibration suppression and vibration reduction effects on various pavements.

碩士
龍華科技大學
電機工程系碩士班
107
The objective of this thesis was to design an adaptive sliding mode controller for use in active suspension systems with pneumatic muscle actuator (PMA) and to then conduct relevant research experiments. The PMA system is a highly nonlinear and time-variant system because of the various properties of air, such as its compressibility, low viscosity, low natural frequency, the hysteresis of proportional valve coils, zero drift, and the dead band in valve movements. Therefore, establishing a precise mathematic model based on the dynamic characteristics of the PMA system for the design of a sliding mode controller is extremely difficult. In response to this difficulty, the present study proposed an adaptive sliding mode controller with a self-turning proportional–derivative (PD) compensator to eliminate the need for an accurate dynamic model of the sliding mode controller and to reduce the difficulty of fabricating a control system. The controller has two parts, the adaptive sliding mode controller and self-turning PD compensator. A Fourier series and the adaptive control are applied to the adaptive sliding mode controller to estimate the unknown nonlinear dynamics for eliminating the need for an accurate dynamic model of the sliding mode controller. In addition, the PD compensator with real-time self-turning functionality is employed to compensate for approximation errors, uncertainties, and disturbances and thus mitigate the effects of approximated errors and unmodeled dynamics on the controller. Moreover, in the controller design, dynamic models and the trial and error method are not required to adjust the control parameters and select approximating functions. This design also resolves the problem of the discontinuous chattering of the sliding mode controller. The entire control system gradually reaches Lyapunov stability, and the tracking error of the system converges to the neighborhood of zero. The adaptive sliding mode controller with self-turning PD compensator was fabricated and applied to a quarter-car active suspension system with PMA that was constructed in the laboratory. The experiment results revealed that the controller was capable of managing dynamic changes on the road and was effective in reducing and suppressing shocks on various bumpy roads.

碩士
國立臺灣大學
機械工程學研究所
105
In this thesis, the hydro-pneumatic suspension system and body structure of the wheeled heavy vehicle are studied. Through the establishment of a set of optimization design process, to design the parameters of the suspension system for vehicle handling and comfort, as well as to optimize the design of the body structure to achieve strength requirements and enhance structural rigidity. First, according to the existing test platform to plan experiments, and then the test results are used to verify and modify the model. And, the performance of the original design are discussed by the simulation analysis. Next, through the vehicle dynamic simulation to get the vehicle dynamic response during the driving process, and found that part of the body structure may be damage under specific load conditions. Therefore, this thesis uses structural optimization method to optimize the structure of the vehicle body, let the structural strength and rigidity are both meet the requirements. In addition, this thesis designs suitable suspension parameters for different road environment and the operation needs of the vehicle, which make the vehicle in the same operating conditions to be more comfortable and with high handling performance, improving the carrying capacity of the wheeled heavy vehicles. And, the design parameters provide the basis for improving performances of the suspension.

碩士
龍華科技大學
工程技術研究所
101
This thesis aimed to apply the pneumatic muscle actuator in the active vehicle suspension system. In addition, through the quarter-car suspension system model, the active vehicle suspension system experimental model was substantially constructed, and vibration reduction and controlled performance were conducted in order to verify the feasibility of the active vehicle suspension system, using the pneumatic muscle as the actuator. In terms of system control, with the active vehicle suspension system of the quarter-car as the targeted, the interval type-2 adaptive fuzzy controller with self-tuning fuzzy sliding mode compensation (IT2AFC-STFSMC) was proposed. With this control method, the controller is composed of two parts, including the single input fuzzy controller and the self-tuning fuzzy sliding mode compensation. Taking advantages from the interval type-2 fuzzy systems, sliding mode control, and adaptive control, the proposed IT2AFC-STFSMC can exclude limitations of the systematic mathematical model needed to design the sliding model controller. In addition, the fuzzy sliding mode compensation with self-regulating ability was added to engage in approximate error and external interference compensation and improve the problem of discontinuous vibrations seen in the sliding model controller. The entire control system possesses asymptotic stability and the system tracking errors converge to a certain neighborhood of zero. In addition to the development of a quarter-car active vehicle suspension system, the controller design was practically applied to the system. The experimental results show that for the interval type-2 adaptive fuzzy controller with self-tuning fuzzy sliding mode compensation, the active vehicle suspension system showed good results in vibration reduction and vibration inhibition on different bumpy road surfaces.

碩士
逢甲大學
機械工程學所
99
This article is about the design of a brand new type of reducing vibration system which is added an air structure onto the normal type of shock absorber. Sometimes the vehicles need to take some high impact, if we provided another protect, the external impact load of vehicles can be decreased. This system is for the situation that while the vehicle is completely off the road in the free fall, the air compress system can absorb the impact energy which cannot be absorbed by the normal type of shock absorber. In another words, when the vehicles are driven on the road, the small vibration from the fluctuate road surface are absorbed by the normal type of shock absorber. However, when it comes to the highly distance falling situation, the adding high pressure air system could helps to auxiliary the original one to reduce the highly instantaneous impact force. This study is using the MATLAB software as an analyzing tool. The mainly job of this work is that simulating the vibration suppress result of with and without added this system, and then compare and observe the influence of the result. In this case we choose the appropriate model parameters import the program. After that we use the fractal dimension and the root mean square theory to analysis the experimental data so that we can define performance index. According to the case, we can compare the damping performance. The test result shows to add the new air compressed system got a good characteristic of reducing vibration. Therefore, we can know that the new equipment is work.

碩士
龍華科技大學
機械工程系碩士班
106
This thesis designed an intelligent controller for quarter-car pneumatic muscle active vehicle suspension systems and conducted an experimental study for the proposed controller. Pneumatic muscle servo systems are time-varying systems with high nonlinearity because of numerous factors such as the air compressibility, low viscous damping force, low natural frequency, the friction forces in the system, the valves’ nonlinear characteristics subjected to loading, the hysteresis of proportional solenoids, zero drift, and dead-zone effect during spool movement. As a result, the associated precise mathematical models is difficult for designing controllers through the model-based control theory. To overcome the limitation involving the need for mathematical models when designing controllers and reduce the difficulty in developing actual control systems, this thesis developed an interval type-2 fuzzy sliding mode controller by integrating interval type-2 fuzzy logic and sliding mode control. However, bouncing tires during tire rotations induce dynamic effects such as tire deformation and unintended vehicle acceleration that obstructs the effectiveness of the integrated interval type-2 fuzzy and sliding mode control. That is, compared with passive control strategies, the proposed control method could not simultaneously elevate riding comfort and vehicle handling. To enhance riding comfort, this thesis incorporated an acceleration feedback interval type-2 fuzzy sliding mode controller into the sprung mass displacement feedback interval type-2 fuzzy sliding mode control framework and then performed an experimental study on the pneumatic muscle active vehicle suspension system. The experiment results showed that for different road surfaces and vehicle speeds, the proposed double-loop interval type-2 fuzzy sliding mode controller in the pneumatic muscle active vehicle suspension system yielded a superior riding comfort compared to passive suspension and active interval type-2 fuzzy sliding control without acceleration compensation.

碩士
龍華科技大學
工程技術研究所
101
This thesis developed a pneumatic-muscle active vehicle suspension system, and designed the controller to provide the better riding comfort and driving controllability. Due to the high nonlinearity and time-variant characteristics of the pneumatic-muscle active vehicle suspension system, it is difficult to establish an accurate dynamic mathematical model of the system to conduct the controller design. This thesis thus used the mathematical model of Haar wavelet series approximation system, along with the adaptive control, sliding mode control and tracking technology, to design an adaptive sliding mode controller of the pneumatic-muscle active vehicle suspension system. The unknown functions in the dynamic mathematical model of system were approximated in combination with the Haar wavelet series and adaptive control to eliminate the limitation of needing the mathematical model of system to design the sliding mode controller. Moreover, the tracking technology was incorporated to compensate for the finite series approximation error and external interference of system and mitigate the discontinuous jump-cut phenomena of sliding mode controller, thus improving the control effect and reducing the difficulty in realizing the actual control system. In addition, the Lyapunov stability criterion was used to obtain the controller parameter updating law to ensure the stability of the controlled process of system. In addition to developing a pneumatic-muscle active suspension system of 1/4 vehicle, this thesis also designed an adaptive sliding mode controller on the system. The experimental results indicated that under the compensation of the adaptive sliding mode controller, the pneumatic-muscle active vehicle suspension system has good vibration damping and suppressing effect on various bumpy road surfaces.

碩士
國立臺灣大學
機械工程學研究所
105
The purpose of this research is to investigate the relationship between the spring coefficient of the suspension and the dynamic stability and handling of a vehicle during cornering. First, we use the basic dynamic principle to compute the dynamic equations of the vehicle. The equations of motion of the system are used to observe the vehicle dynamic characteristics for different spring coefficients of the suspension. We use lateral load transfer ratio to evaluate the dynamic stability and optimal handling performance index of the vehicle to evaluate the handling. In this research, the cornering angle of the front four wheels is applied to simulate. It is assumed that the absolute value of lateral load transfer ratio equals to 1, which represents that the sum of the normal force of the four wheels in one side equals to zero. In this situation, the four wheels are all lift-off and it represents the lowest dynamic stability. The smaller absolute value of lateral load transfer ratio represents the higher dynamic stability of the vehicle. The smaller the optimal handling performance index of the vehicle is, the easier the vehicle reaches the desired track. The most suitable spring coefficients are obtained to achieve o high stability and handling for the vehicle during cornering.