Automatic tracking steering system for off-centered flexible chassis steering axis based on fuzzy-PI composite control

This study focused on the high-precision and efficient steering control of a flexible chassis with a fuzzy-PI composite technique. The flexible chassis is a four-wheel independent steering and four-wheel independent drive electric chassis based on an off-centered steering axis module. The off-centered steering axis module is steered by jointly controlling the speed of the wheel and the locking torque of the electromagnetic steering lock. The fuzzy controller is applied to control the electromagnetic steering lock to reduce steering resistance and accelerate the steering process when the steering angle error is big, and the PI controller is designed to stabilize the steering process and to ensure the accuracy when the steering angle error is small. Simulation results showed that the proposed composite control system is very robust to steering angle without sacrificing high precision and efficiency.