Title: Tuning the fuzzy control autopilot strategy for driving pattern simulation of road vehicles

Authors: Che-Wun Hong

Addresses: Associate Professor, Department of Power Mechanical Engineering, National Tsing-Hua University, Hsinchu 30043, Taiwan, ROC

Abstract: This paper describes the control strategy design of an autopilot system to aid the driving pattern simulation of road vehicles on a chassis dynamometer test stand. A basic fuzzy controller, employing a regular triangle-shaped membership function and a linear defuzzification algorithm, has been proved to achieve the first goal of an experienced driver behaviour simulation. However, the target of not exceeding the speed excursion limits, regulated by the code of the driving pattern, has not been achieved yet. Several improvements have been proposed in this paper through some techniques. Such as: employing a nonlinear defuzzification algorithm, modification of the membership function, and setting up a rule self-regulator. Using a phase-plane analysis technique, it is found that a bell-shaped membership function with the linear defuzzification algorithm is able to achieve the minimum rise time and minimum overshoot for the case of a step response. It is also proved that this simple strategy is suitable to the on-line autopilot control using dynamic driving pattern simulation. In order to apply the autopilot control strategy to various road vehicles on various driving pattern conditions, a simple rule self-regulating fuzzy control model was adopted. The rule self-regulator is equivalent to a self-tuning variable-gain proportional-integral controller. This model has been found to have the potential to enhance the applicability of the fuzzy autopilot system.

Keywords: autopilot systems; driver behaviour; driving patterns; simulation; self-regulating fuzzy control; variable-gain proportional integral controller; PI control; vehicle design; controller design; fuzzy logic.

DOI: 10.1504/IJVD.1997.062043

International Journal of Vehicle Design, 1997 Vol.18 No.1, pp.35 - 52

Published online: 29 May 2014 *

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