Adaptive functional approximation strategy for a four-wheel drive electrical vehicle driving speed control

Abstract

A small-scale electric model vehicle is built with four in-wheel motors. A field programmable gate array is chosen as the control kernel for this electric vehicle system. Since this electric model vehicle has four in-wheel driving motors without differential mechanism, it needs an electronic differential and well-designed control algorithm to manipulate the vehicle driving speed and orientation. Accurate mathematical model of this multi-input and multi-output electric vehicle system is difficult to establish for a model-based controller design. Here, the adaptive functional approximation control scheme is first employed to design the speed controller of each wheel for integrating with the Ackermann–Jeantand model-based electronic differential. A model reference adaptive-proportional–integral–derivative control is designed to manipulate the vehicle steering system. The experimental results show that the proposed adaptive functional approximation control and model reference adaptive-proportional–integral–derivative controllers can effectively monitor the wheel rotational speed and steering angle with rotational speed error and angular error less than 2 r/min and [Formula: see text], respectively. The induced electronic differential model successfully assisted the vehicle turning control and trajectory following control operations.