Multi-target position servo control of hydractive suspension based on extended state observer

The half suspension model established in this paper fully considers the non-linear characteristics of single-rod hydraulic actuators, and designs a sliding mode adaptive controller based on the existence of uncertain parameters and possible external uncertain disturbances in the system. Considering that some of the state variables required by the controller are not easy to obtain, an extended state observer is designed to observe the wheel vertical movement speed and the pressure of the rod cavity and non-rod pressure of the hydraulic actuator. The controller designed in this paper estimates the uncertain parameters through the adaptive law, and can still effectively adjust the body attitude when the system has a strong external disturbance signal. Through the simulation results, it can be seen that the controller always satisfies the hard constraints such as driving safety and suspension stroke due to the restricted mechanical structure while improving the ride comfort of the vehicle. Because the model takes into account the widely used asymmetric single-rod hydraulic actuators and external non-linear disturbances, and designs state observers for some unmeasured state variables, the controller designed in this paper is closer to reality.