H∞ control and experimental study of MR semi-active suspension with actuator response delay

Given the potential negative impact of delayed response from a magnetorheological (MR) damper on the effectiveness of semi-active suspension (SAS), a specialized time-delay dependent H∞ robust controller has been developed to address this issue. The controller accounts for the actuator response delay and determines the system theoretical critical delay. To mitigate the response delay within the electromagnetic loop of the actuator, a technique has been proposed and tested. The technique minimizes the overall response delay, ensuring it is less than the theoretical critical delay. Subsequently, feedback gain is determined and comparative performance tests are conducted to validate the efficacy of the proposed control method. Compared with a delay-independent H∞ robust controller, it has been demonstrated that the body acceleration and dynamic tire load peak-to-peak responses generated by the proposed controller are decreased by 16.4% and 7.4% respectively under bumpy road conditions, while under stochastic road conditions, body acceleration decreases by 3.5%, suspension deflection by 17.1%, and DTL by 0.89%.