Fractional order PID control for steer-by-wire system of emergency rescue vehicle based on genetic algorithm

Abstract

Aiming at dealing with the difficulty for traditional emergency rescue vehicle (ECV) to enter into limited rescue scenes, the electro-hydraulic steer-by-wire (SBW) system is introduced to achieve the multi-mode steering of the ECV. The overall structure and mathematical model of the SBW system are described at length. The fractional order proportional-integral-derivative (FOPID) controller based on fractional calculus theory is designed to control the steering cylinder’s movement in SBW system. The anti-windup problem is considered in the FOPID controller design to reduce the bad influence of saturation. Five parameters of the FOPID controller are optimized using the genetic algorithm by maximizing the fitness function which involves integral of time by absolute value error (ITAE), peak overshoot, as well as settling time. The time-domain simulations are implemented to identify the performance of the raised FOPID controller. The simulation results indicate the presented FOPID controller possesses more effective control properties than classical proportional-integral-derivative (PID) controller on the part of transient response, tracking capability and robustness.