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vehicle-dynamics
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Total 21 records
Direct yaw moment controller design for vehicle dynamic control systems
, Article Proceedings of the IASTED International Conference on Modelling, Sumulation and Optimization, Banff, Alta., 2 July 2003 through 4 July 2003 ; 2003 , Pages 120-124 ; 0889863725 (ISBN) ; Naderkhani, B ; Esmailzadeh, E ; Sharif University of Technology
2003
Abstract
Direct yaw moment control (DYMC) is one of the most effective method that improves not only the directional stability of the vehicles but also their road handling and controllability to a great extent. In this method by developing a difference in the longitudinal force (often the braking force) on two sides of the vehicle, an external stabilizing yaw moment is applied to the vehicle. In this study, an optimal control law for DYMC is proposed. The control law is based on the yaw rate, the lateral velocity feedback, and the steering angle feedforward. Simulation results obtained indicate that considerable improvement in the vehicle dynamic behavior can be achieved when the optimal yaw moment...
Direct yaw moment control for motorized wheel electric vehicles
, Article 18th Biennial Conference on Mechanical Vibration and Noise, Pittsburgh, PA, 9 September 2001 through 12 September 2001 ; Volume 6 A , 2001 , Pages 215-222 ; Esmailzadeh, E ; Vossoughi, G. R ; Sharif University of Technology
2001
Abstract
A new control law for direct yaw moment control of an electric vehicle is developed. Although this study is considered as part of a global control system for the traction control of a four motorized wheel electric vehicle, but the results of this study is quite general and can be applied to other types of vehicles. The dynamic model of the system has been analyzed and, in accordance with the optimal control theory, an optimal controller is designed. Two different versions of the control law have been considered and the performance of each version has been separately studied and compared with each other. Finally, the numerical simulation of the vehicle-handling model with and without the use...
Design and Prototypingof a Fast Acting Anti Roll Over System for SUVs
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
SUVs are susceptible to rollover in high speed due to their shape and high center of mass. This causes numerous limitations for this class of vehicles thus preventing their rollover is a prime issue. In this study, two flywheels with high angular momentum have been used to provide stabilizing momentum on the onset of rollover. However, if these flywheels keep rotating during the normal driving, they will cause maneuvering limitations for the car. The idea of using flywheels is completed by bringing them to speed in a few hundredth of a second when the vehicle is suspicious to rollover.To achieve this, dynamics of the car before and after lift off of one side is investigated. Also the dynamic...
Flexible wheel/rail contact model for railway vehicle dynamics without pre-calculation
, Article 2007 ASME Rail Transportation Division Fall Conference, Chicago, IL, 11 September 2007 through 12 September 2007 ; 2007 , Pages 87-93 ; 10788883 (ISSN) ; 9780791848005 (ISBN) ; Salehi, S. H ; Jalili, M. M ; Sharif University of Technology
2007
Abstract
An advanced method using progressive concept of geometrical correspondence is applied to create a new wheel/rail contact model based on virtual penetration theory. The geometry and contact mechanism are solved simultaneously because of the independency in a defined correspondence. The model takes the penetrated profiles of wheel and rail and also associated creeps as inputs, and produces driving contact forces as output. The advantage of this model is that it doesn't require pretabulation of rigid contact situation. The method allows calculating flexible, non-elliptical, multiple contact patches during integration of the model. Consequently the rails with substructures can vibrate separately...
Directional stability and control of four-wheel independent drive electric vehicles
, Article Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics ; Volume 216, Issue 4 , 2002 , Pages 303-313 ; 14644193 (ISSN) ; Goodarzi, A ; Vossoughi, G. R ; Sharif University of Technology
2002
Abstract
The innovative powertrain configuration of modern electric vehicles with four-wheel independent drive (4WID) provides the possibility of simple and exact yaw moment control by controlling the electric motor of every wheel independently. In this study, a genuine control strategy for optimum direct yaw moment control is proposed. Although this can be considered as a global control system for traction control of 4WID electric vehicles, the analysis is quite general and can be applied to other types of vehicle. The directional vehicle model is derived and, in accordance with the optimal control theory, an optimum yaw moment controller is designed. Two versions of the control law are developed...
Criteria for Evaluating Bogie Performance For Sustaining Ride Quality
,
Ph.D. Dissertation
Sharif University of Technology
;
Sayyadi, Hassan
(Supervisor)
Abstract
This thesis proposes a dynamic model for studding influences of suspension components behavior on rail vehicle dynamics. As the air springs are very important isolating component in rail vehicles, a new complete nonlinear air spring model, with taking into consideration of thermo–dynamical effects, is developed. The model coefficients are tuned based on the real test data and it can be easily used in dynamic modeling of air springs. The new proposed vehicle model is a complete track–vehicle model with 70 degree of freedoms which is addressed as a modular type. Experimental results from complete rail–vehicle field test, showed remarkable agreement between proposed model and test results....
Effect of suspension and body flexibility on dynamic behavior of passenger cars
, Article 2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005, Orlando, FL, 5 November 2005 through 11 November 2005 ; Volume 74 DSC, Issue 1 PART A , 2005 , Pages 529-534 ; 0791842169 (ISBN); 9780791842164 (ISBN) ; Kasaiezadeh, A ; Nakhjavani, O. B ; Sharif University of Technology
2005
Abstract
The usual practice in vehicle dynamic modeling is to consider the body and suspension components as rigid elements. The question this paper is trying to answer is; how large the errors will be if flexibility of the components are not considered in vehicle dynamic model. The flexible vehicle model made for this study has 300000 elements which are generated using Super-element analysis in MSC/NASTRAN and made usable in MSC/ADAMS environment using Craig-Bampton theorem. The full vehicle model made in ADAMS has 200 degrees of freedom and includes all bushings, mechanism, power train, and suspension system. The model was used in simulating ride and handling behavior of the vehicle in several...
Nonlinear Controller Design for Stree-By-Wire Passenger Car
, M.Sc. Thesis Sharif University of Technology ; Kazemi, Reza (Supervisor)
Abstract
Today safety is one of the major competition factors in automotive industries . The vehicles of today are more and more dependent on electronic systems , for driving safety and ease on control for the driver . Some systems are more or less standard in vehicles on the market , examples of such systems are ABS , ABC , etc. Despite of the effect of these systems on vehicle dynamics ,because they only control longitudinal dynamics and don't receive any feedback from vehicle lateral behavior , now control systems ,named VDC , have been developed and implemented in advanced vehicles. The operation of such systems is as this that in any time instance they evaluate vehicle dynamical behavior....
RANS simulation of interceptor effect on hydrodynamic coefficients of longitudinal equations of motion of planing catamarans
, Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 37, Issue 4 , July , 2015 , Pages 1257-1275 ; 16785878 (ISSN) ; Alimirzazadeh, S ; Seif, M. S ; Sharif University of Technology
Springer Verlag
2015
Abstract
Understanding and investigation of a high-speed craft dynamics, their longitudinal dynamic instabilities in calm water and behavior in waves are of a great importance. Determination of motion equation coefficients will help to analyze the dynamics of these kinds of vessels and the factors affecting their dynamic stabilities. Therefore, it could be useful in controlling the vessel instabilities. The main purpose of this research is to determine the coefficients of longitudinal motions of a planing catamaran using computational fluid dynamics (CFD) and evaluating the interceptor effect on hydrodynamic coefficients of that, which is widely utilized in controlling the motions of a high-speed...
A real-time algorithm for variable-objective motion planning over terrain and threats
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 229, Issue 6 , 2015 , Pages 1043-1056 ; 09544100 (ISSN) ; Pourtakdoust, S. H ; Sharif University of Technology
SAGE Publications Ltd
2015
Abstract
A major issue required to enhance the autonomy level of unmanned vehicles is real-time motion planning. In this context, optimal trajectories need to be generated online considering the vehicle's dynamic potentials and constraints. However, autonomous air vehicles often need to plan and execute their missions with varying objectives that may even be dictated in flight. Therefore, the current study introduces and focuses on the new concept of variable-objective motion planning. In this regard, a new dynamic multi-objective heuristic optimization algorithm is developed for path and motion planning of autonomous air vehicles in presence of deterministic terrain obstacles as well as random...
Identification of underwater vehicle hydrodynamic coefficients using model tests
, Article ASME 2010 International Mechanical Engineering Congress and Exposition, IMECE 2010, Vancouver, BC, 12 November 2010 through 18 November 2010 ; Volume 8, Issue PARTS A AND B , 2010 , Pages 165-173 ; 9780791844458 (ISBN) ; Mehdigholi, H ; Sharif University of Technology
Abstract
Predicting the hydrodynamic coefficients of an autonomous underwater vehicle (AUV) is important during vehicle design. SUT-2 is an AUV. being developed by the Marine Engineering Research Center of Sharif University of Technology in Iran (MERC). Model tests are done in the marine engineering laboratory towing tank. In tins research, hydrodynamic coefficients are calculated using model test results of an autonomous underwater vehicle. Hydrodynamic forces are also analyzed. These coefficients are used for dynamic modeling and autonomous controller design
Effects of viscoelastic supports on the behavior of bridges under moving vehicles
, Article Scientia Iranica ; Volume 24, Issue 4 , 2017 , Pages 1751-1769 ; 10263098 (ISSN) ; Vafai, H ; Sharif University of Technology
Sharif University of Technology
2017
Abstract
One of the most important problems facing structural engineers is the analysis of dynamic behavior of bridges subjected to moving vehicles. In addition, viscoelastic supports under bridges change their dynamic behavior under passing traffic loads. This paper presents how to model a bridge with viscoelastic supports and how the maximum dynamic stress of bridges changes during the passing of moving vehicles. Furthermore, this paper presents an algorithm to solve the governing equation of the bridge with viscoelastic supports as well as the equation of motion of a real European truck with different speeds, simultaneously. Using viscoelastic supports with appropriate characteristics can make a...
A new model in rail-vehicles dynamics considering nonlinear suspension components behavior
, Article International Journal of Mechanical Sciences ; Volume 51, Issue 3 , 2009 , Pages 222-232 ; 00207403 (ISSN) ; Shokouhi, N ; Sharif University of Technology
2009
Abstract
In this paper, a complete four axle rail vehicle model is addressed with 70 degrees of freedom (DOFs) including a carbody, two bogies, and four axels. In order to include the effects of the track irregularities in vehicle dynamics behavior, a simplified track model is proposed and it is validated by some experimental data and test results. As the performance of the suspension components, especially for air springs, have significant effects on rail-vehicle dynamics and ride comfort of passengers, a complete nonlinear thermo-dynamical air spring model, which is a combination of two different models, is introduced and implemented in the complete rail-vehicle dynamics. By implementing Presthus...
New dynamics model for rail vehicles and optimizing air suspension parameters using GA
, Article Scientia Iranica ; Volume 16, Issue 6 B , 2009 , Pages 496-512 ; 10263098 (ISSN) ; Shokouhi, N ; Sharif University of Technology
2009
Abstract
In this paper, a complete four axle rail vehicle model with 70 Degrees Of Freedom (DOFs) is addressed, which includes; a carbody, two bogies and four axles. In order to include track irregularity effects on vehicle behavior, a simplified track model for a straight line is proposed. As the performance of the suspension components, especially for air springs, has significant effects on rail-vehicle dynamics and the ride comfort of passengers, a complete nonlinear thermo-dynamical air spring model which is a combination of two different models is introduced and then implemented in the complete rail-vehicle dynamics. By implementing the Presthus formulation [1], the thermo-dynamical parameters...
Swarm aggregation using emotional learning based intelligent controller
, Article 2009 6th International Symposium on Mechatronics and its Applications ; 2009 , Article number 5164827 ; ISBN: 9781424434817 ; Vatankhah, R ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
Abstract
In this paper, we consider a control strategy of multi-robot systems, or simply, swarms, based on emotional control technique. First, we briefly discuss a "kinematic" swarm model in n-dimensional space introduced in an earlier paper. In that model, motion of every swarm member is governed by predefined inter-individual interactions. Limitations of every member's field of view are also considered in that model. After that, we consider a general model for vehicle dynamics of each swarm member, and use emotional control theory to force their motion to obey the dynamics of the kinematic model. Based on the kinematic model, stability (cohesion) analysis is performed and coordination controller.is...
Design, analysis and manufacturing a double wishbone suspension system with variable camber angle by pneumatics mechanism
, Article ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011 ; Volume 7, Issue PARTS A AND B , 2011 , Pages 477-483 ; 9780791854938 (ISBN) ; Mokhlespour, M. I ; Keshavarzi, A ; Hoviat Talab, M ; ASME ; Sharif University of Technology
2011
Abstract
The accuracy of multi dimensional simulation of vehicle dynamics has been significantly increased for both passive and active vehicles which are equipped with advanced electronic components. Recently, one of the subjects that has been considered is increasing the car safety in design. Therefore, many efforts have been done to increase vehicle stability especially during the turn. It is also very important in three wheel car. One of the most important efforts is adjusting the camber angle in the car suspension system. Camber angle as well as the vehicle stability has major effects on the wheel slip, reducing rubber abrasion, acceleration and braking. Since the increase or decrease in the...
Fuzzy trajectory tracking control of an autonomous air vehicle
, Article ICMEE 2010 - 2010 2nd International Conference on Mechanical and Electronics Engineering, Proceedings, 1 August 2010 through 3 August 2010 ; Volume 2 , August , 2010 , Pages V2347-V2352 ; 9781424474806 (ISBN) ; Saghafi, F ; Sharif University of Technology
2010
Abstract
The development and the implementation of a new guidance law are addressed for a six dimensional trajectory tracking problem, three dimensions for position tracking and three dimensions for velocity tracking, of a micro air vehicle. To generate the desired trajectory a virtual leader is defined which is moved in space. In the guidance law, position and velocity feedbacks are used by fuzzy controllers to generate two acceleration commands. Then, a fuzzy coordinator is applied to coordinate the acceleration commands. Nonlinear six-degree-of-freedom equations of motion are used to model the vehicle dynamics. Also, a bank-to-turn acceleration autopilot for vehicle is considered to follow the...
Effects of air reservoir volume and connecting pipes' length and diameter on the air spring behavior in rail-vehicles
, Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 34, Issue 5 , 2010 , Pages 499-508 ; 10286284 (ISSN) ; Shokouhi, N ; Sharif University of Technology
Abstract
The secondary suspension of most new EMU and DMU rail vehicles is equipped with air springs, to offer a good ride comfort to passengers. Air springs are a very important isolating component, which guarantees good ride comfort during the trip. In most rail-vehicle models developed by researchers, the thermo-dynamical effects of air springs in the rail-vehicle dynamics are not considered and secondary suspension is modeled by simple springs and dampers. As the performance of suspension components, especially for air springs, have significant effects on railvehicle dynamics and the ride comfort of passengers, a complete nonlinear thermo-dynamical air spring model, which is a combination of two...
Swarm aggregation using emotional learning based intelligent controller
, Article 2009 6th International Symposium on Mechatronics and its Applications, ISMA 2009, Sharjah, 23 March 2009 through 26 March 2009 ; 2009 ; 9781424434817 (ISBN) ; Vatankhah, R ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
2009
Abstract
In this paper, we consider a control strategy of multi-robot systems, or simply, swarms, based on emotional control technique. First, we briefly discuss a "kinematic" swarm model in n-dimensional space introduced in an earlier paper. In that model, motion of every swarm member is governed by predefined inter-individual interactions. Limitations of every member's field of view are also considered in that model. After that, we consider a general model for vehicle dynamics of each swarm member, and use emotional control theory to force their motion to obey the dynamics of the kinematic model. Based on the kinematic model, stability (cohesion) analysis is performed and coordination controller is...
Multimodel ELM-based identification of an aircraft dynamics in the entire flight envelope
, Article IEEE Transactions on Aerospace and Electronic Systems ; Volume 55, Issue 5 , 2019 , Pages 2181-2194 ; 00189251 (ISSN) ; Roudbari, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
The development of a multiple model-based identification algorithm is addressed in this paper for nonlinear modeling of a conventional aircraft in the entire flight envelope. The dynamic model of an aircraft varies significantly depending on changes in the flight condition of the air vehicle including the altitude and the equivalent air speed. Therefore, the conventional identification approaches for generating a single nonlinear model with time-invariant parameters cannot be used in the entire flight envelope of an aircraft. Accordingly, a multiple model-based approach using nonlinear autoregressive exogenous neural networks is introduced in this paper as a powerful tool in identifying...