Event-triggered based finite-frequency control for vehicle electrohydraulic suspension with force tracking

This study investigates the problem of event-triggered based finite-frequency control for vehicle electrohydraulic suspensions with force tracking. A novel hierarchical control methodology is proposed by designing event-triggered finite frequency and active force tracking controllers to improve the suspension performance. In practical application, active suspension system can be constructed as the network control system under consideration of the electrohydraulic actuator's nonlinear dynamics and parametric uncertainties, and in-vehicle network delay in a unified framework. Then, due to the more sensitiveness of the human body to vertical vibrations in 4-8 Hz and limited in-vehicle network communication resource, an event-triggered finite frequency controller is developed based on the generalized KYP lemma and Lyapunov stability theory. The triggered condition is designed for the network control system with in-vehicle network delay. Other physical constraints including suspension working space, tire dynamic load and actuator saturation are also introduced in this controller design. It can generate the target force to satisfy suspension performance requirements under each triggered instant period. Furthermore, since the nonlinearity and uncertainty always exist in the electrohydraulic actuator, a filter-based adaptive sliding mode control method is employed to design the active force tracking controller. It can precisely drive electrohydraulic actuator to track the target constant force generated by event-triggered finite frequency controller. Finally, the results validate the effectiveness and saving communication resource capability of the proposed control methodology.