Optimal fuzzy robust PID controller for active suspension systems

The suspension systems are responsible for neutralizing the vibrations caused by the roughness of the road surface imposed on the car. In this paper, a quarter car model (with two degrees of freedom) is employed to investigate the exerted vibrations on the suspension system. After developing the equation of motion, a combination of two fuzzy and robust PID (FRPID) controllers is applied to the system to suppress the vibrations. The coefficients of these controllers are parameters that are optimized by the Whale Optimization Algorithm (WOA). It is observed that the proposed approach is successful to control the car suspension system properly with a very low error. Finally, the proposed controller is compared with a recently published method in the literature. As the results show, the proposed control method in this paper provides better outcomes.