Vibration control and performance analysis of full car active suspension system using fractional order terminal sliding mode controller

The main goal of introducing Active Suspension System in vehicles is to reduce the vehicle body motion under road obstacles which improves the ride comfort of the passenger. In this paper, the Full Car Model (FCM) with seven Degrees of Freedom is considered and simulated by MATLAB/Simulink. The Terminal Sliding Mode Controller (TSMC) and Fractional Order Terminal Sliding Mode Controller (FOTSMC) are designed to enhance the ride quality, stability and passenger comfort for FCM. The designed FOTSMC has the ability to provide higher control accuracy in a finite time. The performances of the designed controllers are evaluated by measuring the vehicle body vibration in both angular and vertical direction under bump input and ISO-8608 random input against passive suspension system. The Frequency Weighted Root Mean Square (FWRMS) and Vibration dose value of Body Acceleration as per ISO-2631 are evaluated for FOTSMC, TSMC and PSS. The stability of the FCM is proved by Lyapunouv theory. Further analysis with sprung mass and speed variation of FCM demonstrate the robustness of proposed controller. To investigate the performances of designed controllers, comparison is made with existing Sliding Mode Controller (SMC) which proves that the designed FOTSMC performs better than existing SMC.