Development of a Novel Integrated Control Strategy for Automotive Electric Power Steering Systems

This paper introduces a new approach for controlling electric steering systems. This new control algorithm combines backstepping (BS) and PID (Proportional Integral Derivative) techniques. The output of the PID algorithm is the input of the BS controller. The parameters of the PID algorithm are dynamically adjusted by a fuzzy algorithm with two inputs called FPIDBS. An automotive dynamics model is established in this work to determine the variation of road reaction torque, which considers the influence of other disturbances. The calculations and simulations are performed in the Simulink-MATLAB interface to evaluate the effectiveness of the control algorithm. According to research findings, the value of the controlled object (steering motor angle) always closely tracks the desired signal with negligible error. Under some conditions, the error between the output and reference signals is approximately zero (after rounding) when applying the FPIDBS algorithm. In addition, the power consumption of the FPIDBS controller is lower than that of the conventional BS controller. In conclusion, the stability and adaptation of the system are always guaranteed in all investigated conditions. Note to Practitioners—This paper is motivated by solving problems relating to other disturbances in automotive electric power steering systems. The use of an integrated algorithm is a suitable solution. Based on this idea, we propose an algorithm that combines PID, BS, and fuzzy techniques. The controlled object will be virtualized through the PID controller before becoming an input to the BS controller. The parameters of the PID controller are adjusted flexibly based on a fuzzy technique. The input of the membership functions is the change of driver torque, velocity, and system error, while the fuzzy rule is determined appropriately, which provides high efficiency. The results show that the output values always track the desired signal. In addition, the effects of other disturbances are eliminated almost entirely.