A new approach to an optimal integrated control strategy for electric steering systems

Abstract

The stability of the car when steering is controlled by the power steering system. An optimal integrated algorithm (OSMCPID) for controlling an electric power steering system is proposed in this article. This algorithm is designed based on synthesizing two-component control signals: SMC and PID. The component signals are amplified with specific coefficients determined by an optimized loop algorithm. Determining the optimal value is done iteratively many times based on specific criteria. This is a novelty of the article compared to other previously published studies. Numerical simulation is performed in the MATLAB environment under specific conditions. The study results show that the motor and steering column angles always follow the reference value when the OSMCPID algorithm is used to control the steering system. Under extreme conditions (the fourth case, Tr = 8 Nm), the maximum error of the motor angle is only 5.75°, while the average error does not exceed 0.44°. The chattering phenomenon occurs for motor and steering speeds when road disturbances increase, but it does not affect system stability. Overall, system stability can be maintained in many cases once the system is controlled by the optimal integrated algorithm designed in this work.

Keywords

• Electric power steering system
• OSMCPID algorithm
• Motor angle
• Steering column angle