Multi-objective command filtered adaptive control for nonlinear hydraulic active suspension systems

This paper proposes a new multi-objective command filtered adaptive control strategy for the active suspension systems with nonlinear hydraulic actuators. Firstly, command filters are designed to avoid the influences of the explosion of complexity on hydraulic suspension systems. The output of the command filters replaces the derivatives of virtual control signals to remove the online computational burdens caused by the explosion of complexity in the backstepping technique, which is appropriate for the practical hydraulic suspension systems that the differential coefficients of high-order are difficult to gain. Furthermore, the error compensation signals are designed to eliminate the filtering errors and proved to be bounded. Therefore, the large peaks of the output control forces caused by online computational burdens are eliminated, which means that small control forces can achieve good control results. Then, the ride comfort is improved. The dynamic load ratios and suspension working spaces are proved in small regions, which can guarantee the multi-objective control in nonlinear hydraulic active suspension systems. Finally, the simulation results show the effectiveness of the proposed strategy.