Tesis sobre el tema "Transmission variable"
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1
Burger-Scheidlin, Christoph. "Variable rate transmission over noisy channels". Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3318.
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Hybrid automatic repeat request transmission (hybrid ARQ) schemes aim to provide system reliability for transmissions over noisy channels while still maintaining a reasonably high throughput efficiency by combining retransmissions of automatic repeat requests with forward error correction (FEC) coding methods. In type-II hybrid ARQ schemes, the additional parity information required by channel codes to achieve forward error correction is provided only when errors have been detected. Hence, the available bits are partitioned into segments, some of which are sent to the receiver immediately, others are held back and only transmitted upon the detection of errors. This scheme raises two questions. Firstly, how should the available bits be ordered for optimal partitioning into consecutive segments? Secondly, how large should the individual segments be? This thesis aims to provide an answer to both of these questions for the transmission of convolutional and Turbo Codes over additive white Gaussian noise (AWGN), inter-symbol interference (ISI) and Rayleigh channels. Firstly, the ordering of bits is investigated by simulating the transmission of packets split into segments with a size of 1 bit and finding the critical number of bits, i.e. the number of bits where the output of the decoder is error-free. This approach provides a maximum, practical performance limit over a range of signal-to-noise levels. With these practical performance limits, the attention is turned to the size of the individual segments, since packets of 1 bit cause an intolerable overhead and delay. An adaptive, hybrid ARQ system is investigated, in which the transmitter uses the number of bits sent to the receiver and the receiver decoding results to adjust the size of the first, initial, packet and subsequent segments to the conditions of a stationary channel.
2
Gibbs, John H. "Actuated Continuously Variable Transmission for Small Vehicles". University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1238819759.
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Chuang, Jason C. "Variable Speed Flapping Wing Micro Air Vehicle using a Continuous Variable Transmission Design". Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401813452.
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McCandless, John Gregory. "Design of a belt-driven continuously variable transmission". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12147.
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Kolks, Giacomo y Jürgen Weber. "Electro-hydrostatic compact drives with variable transmission ratio". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71209.
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Electro-hydrostatic compact drives are an emerging technology within a range of industrially available translational drive solutions, combining the specific advantages of hydraulic and electromechanical screw drives. Compared to electromechanical screw drives, hydrostatic drives can vary their transmission ratio with comparably little effort, giving them the key advantage of downsizing the electric drive components for a given load cycle. This paper provides a guideline on how to calculate the downsizing potential of electric motors and inverters arising from variable transmission ratio based on the load regime of a given application. Furthermore, a comprehensive systematisation of the actual switching process is described for systems that are switched by means of switching valves. The presented set of methodology is applied to demonstrators in order to validate the general findings.
6
Wells, Dax B. "Investigation of Mechanical Differentials as Continuously Variable Transmissions". BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2904.
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In recent years the increasing demand for fuel efficient and less pollutant vehicles has stimulated the development of hybrid and electric vehicles. These vehicle platforms often incorporate drivetrains which utilize multiple power sources for vehicle propulsion in an effort to increase fuel mileage and reduce emissions. Coupling multiple power sources, such as an internal combustion engine and electric motor(s), has new challenges in drivetrain design. Understanding the torque and rpm relationships within the power transmission device used to combine power sources is fundamental to overcoming the design challenges associated with hybrid and electric vehicle platforms. Results from this research include the fundamental torque and rpm relationships that exist in a multiple-input, single-output power transmission device. These results were deduced from a test that incorporated two separate power inputs into a differential which combined to produce a single output. Testing displayed that a differential has the ability to function as an infinitely variable transmission (IVT). Additionally, the challenges associated with using a differential as a multiple-input, single-output device were identified. Recommendations for overcoming these challenges are also presented herein. This work provides the basis for future work in powertrain optimization for multiple-input, single-output transmission devices.
7
Andersen, Brian S. "An Investigation of a Positive Engagement, Continuously Variable Transmission". Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1878.pdf.
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Lahr, Derek Frei. "Development of a Novel Cam-based Infinitely Variable Transmission". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/35759.
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An infinitely variable transmission (IVT) is a transmission that can smoothly and continuously vary the speed ratio between an input and output from zero to some other positive or negative ratio; they are a subset of continuously variable transmissions (CVTs), which themselves do not have the ability to produce a zero gear ratio. In this thesis, the operation, analysis, and development of a novel, highly configurable, Cam-based Infinitely Variable Transmission of the ratcheting drive type is presented.
There are several categories of CVTs in existence today, including traction, belt, and ratcheting types. Drives of these types, their attributes, and associated design challenges are discussed to frame the development of the Cam-based IVT. The operation of this transmission is kinematically similar to a planetary gearset, and therefore, its operation is described with that in mind including a description of the six major components of the transmission, those being the cam, followers, carriers, planet gears, sun gears, and one way clutches. The kinematic equation describing its motion is derived based on the similarities it shares with a planetary gearset. Additionally, the equations for the cam design are developed here as the operation of the CVT is highly dependent on the shape of the cam. There are six simple inversions of this device and each inversion has special characteristics and limitations, for example, the available gear range. A method was developed to select the most suitable inversion, gearing, and follower velocity for a given application.
The contact stress between the rollers and cam is the limiting stress within the transmission. A parametric study is used to quantify the relationship between this stress and the transmission parameters. Based off those results, two optimization strategies and their results are discussed. The first is an iterative brute force type numerical search and the second is a genetic algorithm. The optimization results are shown to be similar and successfully reduced the contact stress by 40%. To further improve the transmission performance, several mechanisms were developed for this unique transmission. These include a compact and lightweight differential mechanism based on a cord and pulley system to reduce the contact force on the rollers. In addition, a unique external/inverted cam topology was developed to improve the contact geometry between the rollers and said cam. A prototype was built based on both the optimization strategies and these mechanisms and is described within. Finally, a Prony brake dynamometer with cradled motor was constructed to test the transmission; the results of those tests show the Cam-based IVT to be 93% efficient at low input torque levels.Master of Science
9
Bamhdi, Alwi M. "Variable power transmission in highly Mobile Ad-Hoc Networks". Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2780.
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Mobile Ad Hoc Networks pose challenges in terms of power control, due to their fixed transmission power, the mobility of nodes and a constantly changing topology. High levels of power are needed in wireless networks, particularly for routing. As a result of the increase in the number of communication devices being used, there is the challenge of increased density within these networks, and a need to extend the battery life of communication devices. In order to address this challenge, this thesis presents the development of a new protocol (Dynamic Power AODV), which is an enhancement of the Ad Hoc On Demand Distance Vector (AODV) protocol. The new protocol dynamically adjusts the transmission power based on the range, which depends on node density. This thesis provides a systematic evaluation of the performance of DP-AODV, in a high speed and high density environment, in comparison with three other routing protocols. The experiments demonstrated that DP-AODV performed better than two of the protocols in all scenarios. As compared to the third protocol (AOMDV), DP-AODV gave better performance results for throughput and Power Consumption, but AOMDV performed better in terms of Packet Delivery Fraction rate and End-to-End Delay in some cases.
10
Fecko, Mariusz, Kirk Chang, Heechang Kim, Andrzej Cichocki, Larry Wong, Ray O'Connell, Mark Radke, Tom Young y Thomas Grace. "CAPACITY ALLOCATION FOR TELEMETRY LINKS WITH VARIABLE TRANSMISSION RATES". International Foundation for Telemetering, 2016. http://hdl.handle.net/10150/624232.
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Current IP-based telemetry systems such as iNET perform capacity allocation among multiple
radios under the assumption of uniform link rates. This assumption breaks down when adaptive
modulation is deployed to vary link rates in response to channel degradation. In particular, many
modern radios can increase their transmission rate through adaptive coding. To take advantage
of these increased rates, we designed several iNET Link Manager (LM) bandwidth allocation
algorithms for the future iNET that implements adaptive coding techniques. These new LM
algorithms include both weight-based schemes in which link bandwidth is allocated based on the
priority assigned to the links and queues, as well as a greedy algorithm in which link bandwidth
is allocated strictly based on link rates. We evaluated the effectiveness of these algorithms using
both analytical analysis and test-bed experimentation. Through a rich set of test-cases, we
conclude that a weight-based algorithm in which link priority is assigned using the product of link
weight and link data rate has the best performance, and hence can be considered for the future
iNET LM.
11
Ingvast, Johan. "Quadruped robot control and variable leg transmissions". Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-600.
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Willis, Christopher Ryan. "A Kinematic Analysis and Design of a Continuously Variable Transmission". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/79677.
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This thesis describes a method for analyzing and designing a continuously variable transmission (CVT). The analysis process is implemented in a software package that can be used to tune a CVT for a given application. The analysis is accomplished through the use of kinematic principles as well as equations developed from basic energy balances. Although the theory developed can be applied to any CVT, this thesis focuses on a case study using the Team Industries brand CVT applied to the Virginia Tech Mini Baja Team. The work was motivated by the team's need to have a reliable and inexpensive method for CVT tuning. Previous approaches to CVT tuning were strictly empirical and involved mechanical component replacement in a slow and expensive trialand- error optimization loop. The tuning software is intended to be a first step in the process of properly tuning a CVT for a specific application and not a complete replacement for the empirical methods employed previously.Master of Science
13
Bell, Colin Alexander. "Constant power-continuously variable transmission (CP-CVT) : optimisation and simulation". Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6279.
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A novel continuously variable transmission has previously been designed that is capable of addressing a number of concerns within the automotive industry such as reduced emissions. At the commencement of this research, the design was in the early stages of development and little attempt had been previously made to optimise the design to meet specific measurable targets. This thesis utilises and modifies several design approaches to take the design from the concept stage to a usable product. Several optimisation techniques are adapted and created to analyse the CVT from both a design and tribological prospective. A specially designed optimisation algorithm has been created that is capable of quickly improving each critical component dimension in parallel to fulfil multiple objectives. This algorithm can be easily adapted for alternative applications and objectives. The validity of the optimised design is demonstrated through a simulation-tool that has been created in order to model the behaviour of the CVT in a real automotive environment using multiple fundamental theories and models including tire friction and traction behaviour. This powerful simulation tool is capable of predicting transmission and vehicular behaviour, and demonstrates a very good correlation with real-world data. A design critique is then performed that assesses the current state of the CVT design, and looks to address some of the concerns that have been found through the various methods used. A specific prototype design is also presented, based on the optimisation techniques developed, although the actual creation of a prototype is not presented here. Additional complementary research looks at the accuracy of the tire friction models through the use of a specially design tire friction test rig. Furthermore, a monitoring system is proposed for this particular CVT design (and similar) that is capable of continuously checking the contact film thickness between adjacent elements to ensure that there is sufficient lubricant to avoid metal-on-metal contact. The system, which is based around capacitance, requires the knowledge of the behaviour of the lubricant’s permittivity at increased pressure. This behaviour is studied through the use of a specially-designed experimental test rig.
14
Chin, Hin-Soon. "Transmission of variable bit rate video over an Orwell ring". Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/32384.
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Asynchronous Transfer Mode (ATM) is fast emerging as the preferred information transfer technique for future Broadband Integrated Services Digital Networks (BISON), offering the advantages of both the simplicity of time division circuit switched techniques and the flexibility of packet switched techniques. ATM networks with their inherent rate flexibility offer new opportunities for the efficient transmission of real time Variable Bit Rate (VBR) services over such networks. Since most services are VBR in nature when efficiently coded, this could in turn lead to a more efficient utilisation of network resources through statistical multiplexing. Video communication is typical of such a service and could benefit significantly if supported with VBR video over ATM networks.
15
Basl, Peter A. W. Bakr Mohamed H. Nikolova Natalia K. "An adjoint variable method for time-domain transmission line modeling". *McMaster only, 2007.
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16
Haupt, Brandon Levi. "Design and Analysis of a Positively Engaged Continuously Variable Transmission". Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2635.pdf.
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Maugham, Robin. "Dilution torque control of a gasoline engine". Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268735.
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Cyders, Timothy J. "Analysis and Experimental Comparison of Models of a New Form of Continuously Variable Transmission". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1354807440.
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Tavakoli-Bina, Mohammad. "The bootstrap variable inductance : a new FACTS controller for AC power systems". Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/1043/.
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Randall, Austin B. "Investigation of a Planetary Differential for Use as a Continuously Variable Transmission". BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3311.
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With gas prices on the rise, the demand for high-mileage and low pollution vehicles has taken on an unprecedented role in our society. The production and implementation of electric and hybrid-electric vehicles has recently been a large focus of all major automobile manufacturers. Although these new vehicles have begun to solve much of the expensive fuel consumption and air pollution problems that our economy faces, the initial cost of these vehicles has proven to still be too expensive to capture a significant portion of the market. The further advancement of this technology must not only continue to focus on better fuel efficient and decreased pollution producing vehicles, but also decrease the cost of these vehicles to make them more available and enticing to the general public. Results from this research include one potential solution to reduce the cost of electric and hybrid-electric vehicles. Previous research performed in this area has led to the investigation and bench-top testing of a special type of mechanical system known as a Planetary Differential (PD). An exploration of the functionality of this system has shown that the PD can simplify expensive and complex electronic control systems for electric and hybrid-electric vehicles, thus reducing the cost to the consumer. In this study, fundamental speed, torque and power relationships for the PD were developed and tested under various loading conditions. Advantages and disadvantages of the PD, as compared to other similar mechanical systems, are identified and outlined. Recommendations for future work and implementation of the PD in electric and/or hybrid-electric vehicles are presented herein.
21
Smith, Michael Henry. "Vehicle powertrain modeling and ratio optimization for a continuously variable transmission". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/17801.
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Mercati, Stefano, Fabrizio Panizzolo y Giovanni Profumo. "Power split Hydro-mechanical Variable Transmission (HVT) for off-highway application". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200396.
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Nowadays the needs to fulfill severe emission standards and to reduce the mobile machine operative costs have driven the off-highway industrial research towards new solutions able to increase the overall vehicle efficiency. Within this scenario, smart power split transmissions demonstrated to be a very attractive technology able to achieve the fuel consumption reduction targets, increasing the machine working cycle productivity. Compared to the standard technologies (such as Torque Converters - TC), the power split hydromechanical varible transmissin (HVT), designed and developed by Dana Rexroth Transmission Systems S.r.l. (DRTS), is able to fully decouple the engine to wheel behavior during the machine working cycle, with an higher efficiency than a pure hydrostatic transmission. Due to this fundamental characteristic, the HVT allows the engine to work next to the maximum efficiency point, consequently it is possible to downsize the engine to further increase the fuel saving. The analysis of the field test performed by an off-highway vehicle (Kalmar Cargotec DRG Gloria 450 reachstacker) equipped with a DRTS HVT has been shown along this paper; particular attention has been given to the cycle load spectra, the fuel consumption and the working cycle productivity through a comparison with standard TC technologies.
23
Anderson, John A. "Designing and modeling a torque and speed control transmission (TSCT)". Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1194.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains viii, 69 p. : ill. Includes abstract. Includes bibliographical references (p. 68-69).
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Shellenberger, Michael J. C. "Design considerations for variable power split hydraulic drives for industrial applications". Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=655.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 91 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 68-69).
25
Huval, Danny J. "Heat transfer in variable density, low mach number, stagnating turbulent flows". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/12394.
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Guvey, Serkan. "Dynamic Simulation And Performance Optimization Of A Car With Continuously Variable Transmission". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/2/1095322/index.pdf.
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The continuously variable transmission (CVT), which has been in use in some of
the vehicles in the market today, presents the possibility of decoupling the engine
speed and the vehicle speed. By this way, it is now possible to operate the engine
at its maximum efficient or performance point and fix it at that operating point
without losing from the vehicle speed. Instead of using gears, which are the main
transmission elements of conventional transmission, CVT uses two pulleys and a
belt. By changing the pulley diameters, a continuously variable transmission ratio
is obtained. Besides all its advantages, it has some big drawbacks like low
efficiency, torque transmission ability and limited speed range. With developing
technology, however, new solutions are developed to eliminate these drawbacks.
In this study simulation models for the performance and fuel consumption
of different types and arrangements of continuously variable transmission (CVT)
systems are developed. Vehicles, which are equipped with two different
arrangements of CVT and an automatic transmission, are modelled by using
Matlab’
s simulation toolbox Simulink. By defining the required operating points for better acceleration performance and fuel consumption, and operating the engine at these points, performance optimization is satisfied. These transmissions are compared with each other according to their &
#8216
0-100 kph&
#8217
acceleration performances, maximum speeds, required time to travel 1000 m. and fuel consumptions for European driving cycles ECE and EUDC. These comparisons show that CVT systems are superior to automatic transmission, according to their acceleration and fuel consumption performances. CVTs also provide smoother driving, while they can eliminate jerks at gear shifting points.
27
Cacciatori, E. "Advanced control concepts for a parallel hybrid powertrain with infinitely variable transmission". Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/11017.
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Poweitrain
systems of increasing complexity are being introduced by automotive
manufacturers in order to reduce carbon emissions into the
atmosphere: hybrid electric
vehicles and
continuously variable transmissions represent effective contributions to
achieve the emission reduction
target. The increased complexity calls for more
sophisticated control strategies to be developed; different energy management
approaches have been investigated in the past, in most cases without considering
driveability requirements. Those strategies relying on the knowledge of future driving
conditions cannot be
deployed in a real-time controller and are only used to investigate
patterns of optimal behaviour.
This Thesis
investigates two energy management strategies for an innovative
parallel hybrid powertrain concept with innately variable transmission. This was
developed as part of a government funded research project aiming at demonstrating the
potential fuel economy benefit of such driveline configuration. Both strategies have a
common architecture and
rely on a common scheme to control the transient vehicle
response; this was experimentally calibrated in order to provide improved driveability
levels with
respect to the conventional non hybrid powertrain deploying the same
transmission
concept. This control scheme and its calibration are maintained across the
two
energy management strategies so that consistent vehicle behaviour is achieved and
the cost of driveability in terms of energy usage is preserved.
The first
energy management strategy was heuristically formulated to maximise
operation of the single powertrain components in conditions of maximum efficiency.
Optimal design techniques were adopted for the calibration of the corresponding rule
set. The second
strategy formulation was based on the analysis of the simulation
results obtained from a
dynamic programming model; regression analysis techniques
were used to
provide the necessary knowledge base required for the control rules
formulation and calibration. ln both cases
engineering intuition is required for the
interpretation of the simulation results and for the individuation of patterns of
behaviour.
The
hybrid powertrain provides consistent fuel economy improvements with
respect to the equivalent non hybrid powertrain with innately variable transmission. A
driveability appraisal was conducted and the subjective ratings showed an improved
overall
driveability level of the hybrid powertrain. Despite producing different control
and state
trajectories, both strategies provide similar fuel economy figures across a set
of
legislative drive cycles thus demonstrating that both approaches effectively exploit
the hardware limits of the
powertrain plant.
28
Akinsolu, Ojuetimi Ifedayo. "A design of variable transmission power control for wireless ad-hoc network". Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/13559.
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Includes bibliography.Wireless Ad-hoc Network has emanated to be a promising network paradigm that can handle last mile technology due to unprecedented growth of internet users. This network is promising because it extends network to remote areas such as congested environments, rural environments etc. It is known that nodes involved in Wireless Ad-hoc Network rely on battery energy as their source of power. Energy consumption has become one of the major challenges experienced in Wireless Ad-hoc Network, which must be properly tackled. This could be traced to the effect of transmission power on the nodes in the network. Transmission power largely determines the amount of energy consumed by each node in the network. Therefore, a power control technique must be adopted in order to manage and select the optimal transmission power with respect to distance. This transmission power must be sufficient to transfer information from one node to another. Literature have proposed different algorithms for power control technique in Wireless Ad-hoc Network. Some researchers looked at the power control technique in terms of minimising energy consumed from different perspectives, which include power aware routing and power control topology management. However, most of these algorithms were applied at different layers in OSI model such as physical layer, data link layer, network layer and application layer. To achieve a reduced energy consumption at each node in the network, a novel algorithm for transmission power control was designed to select optimal transmission power. The proposed algorithm was designed in such a way that it selects transmission power based on the distance between the nodes without affecting the network throughput. Graph theory is used in this research to model the network topology, and transmission power with respect to the distance.
29
Cacciatori, Enrico. "Advanced control concepts for a parallel hybrid powertrain with infinitely variable transmission". Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/11017.
Texto completoResumen
Poweitrain systems of increasing complexity are being introduced by automotive manufacturers in order to reduce carbon emissions into the atmosphere: hybrid electric vehicles and continuously variable transmissions represent effective contributions to achieve the emission reduction target. The increased complexity calls for more sophisticated control strategies to be developed; different energy management approaches have been investigated in the past, in most cases without considering driveability requirements. Those strategies relying on the knowledge of future driving conditions cannot be deployed in a real-time controller and are only used to investigate patterns of optimal behaviour. This Thesis investigates two energy management strategies for an innovative parallel hybrid powertrain concept with innately variable transmission. This was developed as part of a government funded research project aiming at demonstrating the potential fuel economy benefit of such driveline configuration. Both strategies have a common architecture and rely on a common scheme to control the transient vehicle response; this was experimentally calibrated in order to provide improved driveability levels with respect to the conventional non hybrid powertrain deploying the same transmission concept. This control scheme and its calibration are maintained across the two energy management strategies so that consistent vehicle behaviour is achieved and the cost of driveability in terms of energy usage is preserved. The first energy management strategy was heuristically formulated to maximise operation of the single powertrain components in conditions of maximum efficiency. Optimal design techniques were adopted for the calibration of the corresponding rule set. The second strategy formulation was based on the analysis of the simulation results obtained from a dynamic programming model; regression analysis techniques were used to provide the necessary knowledge base required for the control rules formulation and calibration. ln both cases engineering intuition is required for the interpretation of the simulation results and for the individuation of patterns of behaviour. The hybrid powertrain provides consistent fuel economy improvements with respect to the equivalent non hybrid powertrain with innately variable transmission. A driveability appraisal was conducted and the subjective ratings showed an improved overall driveability level of the hybrid powertrain. Despite producing different control and state trajectories, both strategies provide similar fuel economy figures across a set of legislative drive cycles thus demonstrating that both approaches effectively exploit the hardware limits of the powertrain plant.
30
Dalling, Ryan R. "An Investigation of Positive Engagement, Continuously Variable Transmissions". Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2391.pdf.
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Paté, David. "Diffusion de séquences animées à qualité variable". Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13176.
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Saribay, Zihni Burçay Smith Edward C. Rao Suren B. Bill Robert C. Wang K. W. "Analytical investigation of the pericyclic variable-speed transmission system for helicopter main-gearbox". [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4689/index.html.
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Tawi, K. B. "Investigation of belt misalignment effects on metal pushing v-belt continuously variable transmission". Thesis, Cranfield University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387629.
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Sanhaji, Mani Ahmed. "Contribution à la réalisation d'un système de transmission de couple à vitesse variable". Rouen, 1995. http://www.theses.fr/1995ROUES057.
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Les travaux de la thèse portent sur une contribution à la réalisation d'un système de transmission de couple à vitesse variable afin d'aboutir à ce que l'on pourrait appeler une boite de vitesse électromécanique à variation continue. Un moteur asynchrone et un alternateur sont couplés de façon rigide par leurs rotors. Le stator du moteur asynchrone est entraîné en rotation par l'application d'une puissance motrice extérieure P1 avec un couple de rotation G1. Le stator de l'alternateur, qui est le siège des courants induits, tourne selon la puissance P2 transmise avec un couple G2. L'énergie électrique fournie par les phases statoriques de l'alternateur est récupérée afin de contribuer à l'alimentation électrique du système. Le projet a pour but de régler le rapport G2/G1 avec un rendement P2/P1 maximum. Dans un premier temps, nous proposons les solutions technologiques pour guider en rotation les stators du moteur asynchrone et de l'alternateur. Nous traitons ensuite le problème des pertes d'énergie au cours du régime transitoire du système de transmission de couple. Grâce à la méthodologie de commande proposée pour les machines, nous montrons qu'un réglage judicieux de la durée du régime transitoire permet de réduire ces pertes d'énergie. Cette méthodologie consiste d'une part à maintenir constant le flux statorique du moteur asynchrone, et d'autre part à varier sa fréquence statorique suivant une rampe linéaire.
35
Deacon, Michael. "Optimising the control of a passenger car diesel engine and continuously variable transmission". Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362258.
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Micklem, J. D. "The investigation and modelling of the steel compression V-belt continuously variable transmission". Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359731.
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James, Iain B. "Dynamic characteristics of a split-power IVT". Thesis, University of Bath, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390305.
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Subbalakshmi, K. P. "Joint source-channel decoding of variable-length encoded sources with applications to image transmission". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0013/NQ61684.pdf.
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Rose, Adam. "Application of a continuously variable transmission to engine boosting and exhaust energy recovery systems". Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636513.
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Governments across the world are implementing legislation for ever more strict limits for vehicle emissions; combined with customer expectations for growing levels of performance and equipment, automotive manufacturers face a significant challenge. With the aim of meeting this challenge, downsizing is an established trend in passenger car engine development. However, since downsizing is commonly achieved through pressure charging (turbocharging, for example), the associated benefits in improved fuel economy and emissions are often obtained at the expense of engine dynamic response, and, consequently, vehicle driveability. This thesis presents predominantly simulation-based research into a novel combined charging system comprising a conventional turbocharger used in conjunction with a declutchable supercharger driven through a CVT. An initial investigation using this system in place of a variable geometry turbocharger on an already downsized passenger car diesel engine demonstrated greatly increased low speed torque as well as improved dynamic response. A downsizing project that involved replacing a naturally aspirated gasoline engine with a highly boosted engine with 40% of the original displacement formed the basis for more extensive investigations. Although it was unable to produce the low speed transient response of the naturally aspirated engine, in tip-in tests the CVT-supercharger system was shown to achieve the target torque much quicker than an equivalent system with a fixed supercharger drive ratio. However, balancing this with good fuel efficiency for the initial part load period was a complex trade-off. In vehicle acceleration simulations the CVT-supercharger system did not outperform the fixed drive ratio configuration, but on the CVT system the boost limit was reached at an early stage during the transients. Thus there may be potential to include an ‘over-boost’ facility, allowing boost pressure to temporarily exceed normal steady state limits in order to improve transient performance and bring it closer to that of the baseline vehicle. It is suggested that the CVT-supercharger provides the best flexibility for calibration and compromise between performance and fuel efficiency, perhaps incorporating different user-selectable modes (such as ‘economy’ and ‘sport’ modes).
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Messick, Matthew James. "An Experimentally-Validated V-Belt Model for Axial Force and Efficiency in a Continuously Variable Transmission". Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85055.
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Rubber V-belt Continuously Variable Transmissions (CVT's) are commonplace in the Baja SAE collegiate design competition, and are also used widely in the power sports industry. These transmissions offer benefits of simplicity in mechanical design, consisting of only two pulleys, and are easy to use. While most teams in the competition use commercially available designs, custom designs are becoming more common, and the Baja team at Virginia Tech has used custom CVT's since the 2014 season. The design of these CVT's has relied heavily on trial and error, requiring significant adjustments to be made during the testing phase. In addition, only qualitative information is known for the relationship between efficiency and design parameters, such as sheave angle. The goal of this thesis is to create an improved V-belt model that may be used as a design tool. This model provides quantitative information about efficiency that can be used to make more informed design decisions. The belt model also provides insight into the magnitude and relationship between the axial forces in the pulleys. This can be used to create an initial design that is more accurate, and possibly reduce the time required for tuning. A CVT dynamometer was constructed to validate the analytical results for efficiency, and this will also serve as a tuning tool for future Baja teams at Virginia Tech. This thesis will advance the state of the custom CVT design and testing process at Virginia Tech, and hopefully lead to improved results at competition in the future.Master of Science
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Athanasiadis, Nikolaos P. "Modelling, control and design of Flexible AC Transmission Systems (FACTS), custom power devices and variable speed drives for transmission and distribution architectures". Thesis, University of Strathclyde, 1999. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21441.
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The main tasks of power electronics in power transmission and distribution systems is to process and control the flow of electric energy by supplying voltages and currents in a form that is suitable for user loads. In recent years, the field of power electronics has experienced a large growth. Electric utilities expected that by the year 2000 over half of the electrical load may be supplied through power electronic systems. In order to take advantage of this highly developed technology a number of detailed modelling procedures and simulation facilities are needed. The work in this thesis is concentrated on modelling, control and design of various power electronic based models for use within transmission and distribution systems. The overall objective is to provide effective methods and tools for assessing the impact of the latest technology based on power electronic devices in the reinforcement of power system networks. The thesis clarifies modelling and control of various variable speed drive models, such as the six-step, PWM and vector control and gives a detailed account of the systematic derivation of equations that are necessary for the dynamic and transient analysis of a multi-machine multi-node power system with associated adjustable speed drives. Simulation of Flexible AC Transmission Systems (FACTS) models has also been developed for a number of devices including: the SVC (Static Var Compensator), the STATCON (Static Condenser) and the UPFC (Unified Power Flow Controller). The methodologies for development of the models are described and a number of case studies are included in order to give a broad overview of the applications and to prove the usefulness of the results. The last part of the thesis includes simulation, control and design of Custom Power Devices for use within distribution system architectures. It starts with a complete control system strategy for the modelling of a solid-state switch and continues with the modelling of a Dynamic Voltage Restorer model, using an innovative control system. The creation of the power electronics models library provides several opportunities for future developments, which are discussed in the concluding sections of the thesis.
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Velazquez-Carrillo, Gerardo A. "Prototypage virtuel des boites de vitesses automatiques : Application à une pompe à palette à cylindrée variable". Toulouse, INSA, 2008. http://www.theses.fr/2008ISAT0051.
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Le travail présenté dans ce mémoire concerne la contribution au prototypage virtuel du groupe motopropulseur des automobiles. Il s'agit en particulier d'étudier une pompe à palettes à cylindrée variable qui constitue la source de pression des systèmes de pilotage électrohydrauliques des boites de vitesse automatiques. Les développements sont appliqués à l'exemple d'une pompe de boite de vitesse à cinq rapports qui est produite par General Motors à Strasbourg. Les contributions les plus importantes portent en premier lieur sur la structuration du modèle, l'étude détaillée des ondulations de cylindrée en fonction de l'excentration et de la position angulaire du rotor, la proposition et la mise en œuvre de passerelles entre les outils de CAO et de simulation. Un travail important réside également dans la proposition d'une approche d'optimisation de la distribution angulaire des palettes en vue de réduire le bruit de la pompe. La dernière partie des travaux porte sur la conception, l'intégration et la mise au point d'un banc d'essai permettant la validation expérimentale du modèleThe research presented in this report deals with the contribution to virtual prototyping of the automotive powertrain. The particular interest is the study of a variable displacement vane pump which is the pressure source for the electrohydraulic control systems of automatic gearboxes. The developments are applied to a five speeds automatic transmission hydraulic pump which is manufactured at General Motors Strasbourg. The most important contributions are, in first place, by the model structure, the detailed study of the displacement variation as a function of the eccentricity and the angular position of the rotor, the proposal and application of an interface between CAD and simulation tools. Another important work is the proposal of an optimization process of the angular distribution of the pump vanes to reduce the annoying noise of the pump. The last part of this work is dedicated to the design, integration and fine-tuning of a test bench which allows experimental validation of the virtual model
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Toussile, Wilson. "Sélection de variable : structure génétique d'une population et transmission de Plasmodium à travers le moustique". Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00553674.
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Dans cette thèse, nous considérons la question de sélection de variable dans deux deux problèmes pratiques. Le premier concerne une préoccupation très récurrente en génétique des populations qui consiste à regrouper les individus d'un échantillon d'organismes vivants dans des classes génétiquement homogènes sur la base d'informations procurées par un certain nombre de marqueurs génétiques. Nous supposons ne disposer d'aucune information à priori sur la population cible : il s'agit alors d'un problème de classification non supervisée. Par ailleurs, certaines variables peuvent ajouter du bruit à la classification. Nous proposons de résoudre simultanément le problème de sélection de variable et celui de sélection du nombre de composants du mélange dans une procédure de sélection de modèle. La sélection est ensuite faite via pénalisation du maximum de vraisemblance pénalisé. Sous des hypothèses faibles sur la fonction de pénalité, nous montrons que la procédure de sélection est consistance. Nous construisons ensuite une fonction de pénalité garantissant une inégalité oracle non-asymptotique. Bien que ce deuxième résultat ne soit pas directement utilisable, il suggère une pénalité de la forme du produit de la dimension des modèles en compétition et d'un paramètre données-dépendant que nous calibrons grâce à l'heuristique de la pente. Nous montrons sur des données simulées que cette calibration répond en partie au problème du choix du critère de sélection en fonction de la taille de l'échantillon. Le deuxième problème est motivé par le contrôle de la transmission de Plasmodium à travers son vecteur moustique. Nous disposons de données décrites par des variables diverses dont le nombre est de l'ordre de la taille de l'échantillon. Nous appliquons tout d'abord une procédure de sélection de variable qui repose sur l'importance des variables obtenues des forêts aléatoires. Les variables sélectionnées sont ensuite évaluées dans le modèle binomial négatif modifié en zéro.
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Katariya, Ashish Santosh. "Dynamic modeling and feedback control with mode-shifting of a two-mode electrically variable transmission". Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45825.
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This thesis develops dynamic models for the two-mode FWD EVT, develops a control system based on those models that is capable of meeting driver torque demands and performing synchronous mode shifts between different EVT modes while also accommodating preferred engine operating points. The two-input two-output transmission controller proposed herein incorporates motor-generator dynamics, is based on a general state-space integral control structure, and has feedback gains determined using linear quadratic regulator (LQR) optimization.
Dynamic modeling of the vehicle is categorized as dynamic modeling of the mechanical and electrical subsystems where the mechanical subsystem consists of the planetary gear sets, the transmission and the engine whereas the electrical subsystem consists of the motor-generator units and the battery pack. A discussion of load torque is also considered as part of the mechanical subsystem. With the help of these derived dynamic models, a distinction is made between dynamic output torque and steady-state output torque.
The overall control system consisting of multiple subsystems such as the human driver, power management unit (PMU), friction brakes, combustion engine, transmission control unit (TCU) and motor-generator units is designed. The logic for synchronous mode shifts between different EVT modes is also detailed as part of the control system design. Finally, the thesis presents results for responses in individual operating modes, EVT mode shifting and a full UDDS drive cycle simulation.
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Lewis, Fraser Iain. "Assessing the impact of variable infectivity on the transmission of HIV among intravenous drug users". Thesis, University of Strathclyde, 2000. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=20368.
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The spread of HIV and AIDS is a serious and increasing global problem with the sharing of contaminated injection equipment a primary cause of HIV infection in the developed world. Mathematical models of disease transmission allow us to assess the impact of different epidemiological and behavioural assumptions on the long term behaviour of disease. Initially a simple deterministic model is examined which allows intravenous drug users to progress through three different infectious stages after initial infection with HIV and prior to the development of AIDS. This model is then developed to also allow contaminated injection equipment to exist in three different states of infectivity. The resulting model contains a number of parameters, which while potentially important, are extremely difficult to estimate. In response to this, several special cases are examined which represent intuitive upper and lower bounds for the spread of disease. In each case an equilibrium and stability analysis is presented. Later these special cases, together with a generalisation of them, are compared with a well established single stage infectivity model to ascertain whether the inclusion of variable infectivity increases the predicted spread of disease. We find that the impact of variable infectivity depends on a number of factors and can lead to either an increase or decrease in the prevalence of disease. Testing drug users for the presence of HIV has been proposed as a method of reducing the incidence of HIV. Using the previously discussed upper and lower bound variable infectivity models, we examine the effect of testing addicts for HIV using a number of different infectivity assumptions. We find that under certain conditions HIV testing can be an effective control strategy against the future spread of HIV. This is followed by a short discussion of sensitivity analysis of these models. While predominantly discussing deterministic models we conclude with a brief discussion of stochastic models and demonstrate the behaviour of these models using simulation.
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Mullen, John A. "Analytical and Experimental Comparison of a Positive Displacement Water Pump Using an Infinitely Variable Transmission". Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1492125053378972.
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Huang, Chin-Ching y 黃智清. "Control of Hydrostatic Variable Transmission". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/854pnb.
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碩士國立虎尾科技大學
機械與機電工程研究所
98
In this research, a new hydrostatic-transmission with shift control scheme is developed. Coupled with a 2-DOF planetary gear set, a hydraulic package of a reversible variable-displacement hydraulic pump/motor and accumulator is used to replace the conventional continuously variable transmission (CVT) to optimize energy economy. With this hydrostatic system, nearly all of the energy typically lost during vehicle braking is captured and used to propel the vehicle the next time it needs to accelerate. Compare with conventional CVT system, the benefits of hydrostatic-transmission system include: better energy economy, better acceleration, less brake maintenance, and longer battery life. In this study, the prime task is to analyze the operating characteristics and performance of the hydrostatic-transmission system and derive an optimal control strategy for power shift. Then, a test bench of hydrostatic-transmission system is arranged to perform operating tests for verifying the performances of the developed systems. For optimizing energy economy and smoothing shift control, a genetic algorithm (GA) based adaptive neural sliding mode control (GANSMC) is proposed to control the hydrostatic -transmission system. The control parameters of GANSMC can be properly adjusted by using online parameters tuning algorithm derived from GA. Compare with PI controller, the experimental results show that this novel controller has good control performance, stability, and robustness.
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Cho, Chang-Yeh y 卓昌衍. "Vibrations of Flat Belt Continuously Variable Transmission". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/41258074367675159689.
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Tu, Yu-Jui y 杜育瑞. "Electronically-Controlled Continuously Variable Transmission Systems for Motorcycles". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/x9htrv.
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碩士崑山科技大學
機械工程研究所
91
The V-belt Continuously Variable Transmission (CVT) systems are widely used in almost all kinds of scooters. The major mechanism of the traditional CVT is composed of centrifugal rollers, the compression spring and the torque cam. They are used to adjust the speed ratios for complying with the engine speed and the rear wheel load. In addition to the low transmission efficiency at the lower speed, the centrifugal rollers and movable flange have the worn-up problems which may reduce the materials life-cycle. In order to improve these problems, the aim of our study is to design a brand new Electronically-Controlled Continuously Variable Transmission (ECCVT) system to overcome the limitation of the traditional CVT mechanism. In stead of the centrifugal rollers and movable flange, the new ECCVT use the electronic control equipment to change the speed ratios. Therefore, it gets rid of the material worn-up problems. The ECCVT system can also provide the overall system with higher durability and reliability, and the accurate movement. Combined with the sensor signals of the engine speed, the vehicle speed and the TPS (Throttle Position Sensor), the suitable speed ratio can be calculated. One ECCVT system can be used for different types of engines and in different kinds of driving conditions. By controlling the shift timing and the changing speed of speed ratios, the ECCVT can fulfill the various engine configurations and loading. Therefore, the ECCVT system can be expected to have better power transmission and higher energy transferred efficiencies. At the present stage, the design and experiment test of the new ECCVT system have been accomplished, the experiment results show that the ECCVT system can provide a better transmission efficiency at the lower speeds and the worn-up problems can be avoided. When the external load is changed from 1.16 N-m to 5.8 N-m, the transmission efficiency increases from 45% to 80% obviously. But the increasing tendency is becoming smoothly when the load is above 3.48 N-m. Based on the dynamic test data, the average transmission efficiency of the ECCVT system is 5% higher than that of the traditional CVT system. But, if the speed changed of speed ratio is too fast, the transmission efficiency will drop obviously while the speed ratio starts to change and latter-on the transmission efficiency will increase with the increasing speed ratios.
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Hsu, Ying-feng y 徐英峰. "Controller Design for Transmission Systems with Variable Compliance". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/41921876273809349685.
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碩士國立中山大學
機械工程學系研究所
89
Transmission mechanism is usually modeled as a rigid component in most control tasks of manufacturing processes. Nevertheless, experimental studies have shown that the inherent compliant characteristic of transmission mechanisms seriously degrades the whole system’s performance. This paper presents an adaptive control strategy to overcome positioning difficulty of a transmission system with a variable compliance. A flexible joint, consisting of sixteen linear springs, is designed for actual positioning experiments. In order to enhance variation of the compliance, an eccentric load is located behind the flexible joint. Therefore, the axial compliance is not fixed and will change according to the load’s angular position. The proposed controller is developed on an adaptive control structure to provide capability of fast adaptation to compliance variation. Besides, the robustness of the control system is also specifically emphasized to improve positioning performance with respect to model uncertainty and unknown disturbances. The control law is obtained by applying the Lyapunov’s theorem. Effectiveness of the presented control method is demonstrated on trajectory control of an experimental transmission mechanism with the flexible joint under variable compliance conditions.