Enhanced MR suspension systems via optimised cascade PI-PD control

This study proposes a cascade PI-PD controller to enhance the performance of an MR-damped semi-active vehicle suspension system. The controller is optimised using a multi-objective salp swarm algorithm (MSSA). The suspension system is modelled as five degrees of freedom (five DOF) half-vehicle, and its equations of motion are simulated in MATLAB/Simulink. Performance is evaluated under double bump and random road excitations, focusing on bounce and pitch dynamics. Key performance indicators, including suspension deflection, body acceleration, and dynamic tyre deflection, are analysed in both time and frequency domains. The MSSA-based PI-PD controller outperforms passive strategies, including conventional passive and zero-voltage MR systems, achieving reductions of up to 26% in body acceleration, 49% in suspension deflection, and 27% in dynamic tyre deflection. Compared with standard PID and skyhook controllers, it provides up to 20% improvements in ride comfort and handling, demonstrating its superior effectiveness across passive and semi-active control approaches.