Design and performance evaluation of a novel fractional order PID control strategy for vehicle semi-active suspension

The performance of a semi-active suspension depends on the quality of the control algorithm. Considering the limitations of conventional PID controllers within intricate nonlinear systems, such as imprecise parameter tuning and performance deterioration, we introduced a fractional-order PID (FOPID) control strategy for vehicle semi-active suspension, this approach amalgamates fractional-order theory with conventional PID control to enhance both the controllable scope and precision of the suspension system. Research on semi-active suspension control was conducted using a nonlinear dynamic model of a quarter vehicle. Simulations and analyses were performed utilizing random road excitation and impact road excitation as input signals for both FOPID control, Fuzzy-PID control, and conventional PID control strategies. The analysis findings demonstrated that in the presence of random road excitation, the semi-active suspension system controlled by FOPID reduced vehicle body acceleration by 18.9%, in contrast to a 14.7% reduction by the Fuzzy-PID-controlled suspension, and a 12% reduction achieved by the PID-controlled suspension when compared to the passive suspension. In response to impact road excitation, the suspension system under FOPID control effectively mitigated the peak value of vehicle body acceleration by 29.4%, surpassing the 25.2% reduction achieved by Fuzzy-PID-controlled suspension, and the 24.6% reduction achieved by the PID-controlled suspension. The simulation outcomes substantiated that ride comfort and handling stability of the semi-active suspension system were effectively improved by the implementation of FOPID control.