H ∞ /GH ₂ static output-feedback control for magnetorheological semi-active suspensions with actuator delay

With the aim of addressing the actuator delay issue in magnetorheological (MR) semi-active suspension systems, this paper investigates and designs an efficient control strategy to enhance the vehicle vertical dynamic performance. First, by establishing forward and inverse models that accurately describe the response characteristics of MR dampers, a quarter-vehicle suspension system model incorporating time-delay elements was constructed. The control objectives and performance constraints for the system were clearly defined. Building upon this foundation, to balance system robustness and comprehensive performance while accounting for the limitations of actual measurable signals, a static output-feedback controller synthesis method based on H ∞ / GH 2 theory is proposed. Finally, through simulations and experiments under two typical road conditions, namely, transient impact road and steady-state random road, the effectiveness and superiority of the proposed control strategy were validated. The results demonstrate that compared to passive suspension and traditional time-delay independent H ∞ control methods, the proposed control strategy not only effectively suppresses body vibration and significantly enhances ride comfort, but also stabilizes suspension rattle space (SRS) and dynamic tire load (DTL) within safe limits, thereby comprehensively optimizing vehicle dynamic performance. It provides a complete and feasible technical solution for addressing suspension control problems involving actuator delays.