LQR and PID Controllers Performance on a Half Car Active Suspension System

Suspension systems are responsible for achieving multiple objectives regarding the vehicle’s performance such as ride comfort and road stability. Therefore, active and semi-active suspension systems are developed to achieve those two contradicting objectives. A force actuator allows the system to effectively achieve these two objectives as much as needed. In this paper, we are interested in that control problem. Linear quadratic regulator (LQR) optimal control and PID classic control are designed and studied. LQR as an optimal control algorithm is tuned to provide the best possible performance within the limits of actual and attainable force values. A comparison between the LQR and the PID is carried out, and the performance of each controller is simulated against different kinds of inputs representing different types of bumps and road disturbances. The simulation shows LQR to be of better performance in regards to the maximum overshoot and the profile of the force utilized, while PID has better settling time and better mean absolute error.