Event-triggered H_∞ control for active seat suspension systems based on relaxed conditions for stability

An event-triggered H_∞ controller is designed for an active seat suspension in this paper, where the continuous event-trigger scheme is applied to transfer the dynamic system states to the controller only at event-triggered time instants. Delay-dependent stability criteria in the form of linear matrix inequality (LMI) are presented to guarantee the asymptotic stability of the seat suspension system. One Lyapunov function is chosen where some matrices are introduced with relaxed conditions. Two tight inequalities are applied to prove the positive definiteness of the Lyapunov function and stability of the system, which reduces the conservatism of the system for the time delay to the controller. The proposed control method can reduce the workload of data transmission of the seat suspension system and work as a filter to remove the effect of noise, so it can decrease the precision requirement of the actuator, which can help to reduce the cost of the seat suspension. Both simulation and experimental results are presented to show the effectiveness of the proposed control method.