Title page for ETD etd-09202010-202652


Document Type Master's Dissertation
Author Kasanalowe Nkhoma, Richard Chimkonda
Email rnkhoma@gmail.com
URN etd-09202010-202652
Document Title Use of individual wheel steering to improve vehicle stability and disturbance rejection
Degree MSc
Department Mechanical and Aeronautical Engineering
Supervisor
Advisor Name Title
Prof N J Theron Supervisor
Keywords
  • robust control
  • IWS
  • disturbance rejection
  • yaw rate
  • four wheel steering
  • lateral acceleration
  • 4WS
  • individual wheel steering
  • robust decoupling
Date 2010-09-02
Availability unrestricted
Abstract

The main aim of this research project is to extend theories of four-wheel-steering as developed by J. Ackermann to include an individually steered four-wheel steering system for passenger vehicles. Ackermannís theories, including theories available in this subject area, dwell much on vehicle system dynamics developed from what is called single track model and some call it a bicycle model. In the bicycle model, the front two wheels are bundled together. Similarly, the rear wheels are bundled together. The problem with this is that it assumes two front wheels or two rear wheels to be under the same road, vehicle and operating conditions. The reality on the ground and experiments that are conducted are to the contrary. Therefore this study discusses vehicle disturbance rejection through robust decoupling of yaw and lateral motions of the passenger vehicle.

A mathematical model was developed and simulated using Matlab R2008b. The model was developed in such a way that conditions can be easily changed and simulated. The model responded well to variations in road and vehicle conditions. Focus was in the ability of the vehicle to reject external disturbances. To generate yaw moment during braking, the brake on the left front wheel was disconnected. This was done because lateral wind generators, as used by Ackermann, were not available. The results from both simulations and experiments show disturbance rejection in the steady state.

Copyright © 2009, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

Please cite as follows:

Kasanalowe Nkhoma, RC 2009, Use of individual wheel steering to improve vehicle stability and disturbance rejection, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-09202010-202652/ >

E10/604/gm

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