Disturbance Observer-Based Fixed-Time Event-Triggered Control for Networked Electro-Hydraulic Systems With Input Saturation

The electro-hydraulic system (EHS) has been widely utilized in modern industry due to its high power-to-weight ratio and payload capacity. In this study, a disturbance observer-based fixed-time event-triggered controller is designed for a networked EHS with input saturation. First, a fixed-time disturbance observer (FTDO) is designed to compensate for the model uncertainties and unknown external disturbance. Subsequently, to alleviate the communication pressure of the EHS, a switching threshold event-triggered mechanism (STETM) is constructed to determine the control voltage update. Additionally, an input saturation estimator (ISE) is used to avoid the input saturation caused by the high-order error items and derivative explosions of virtual control variables. The rigorous theoretical derivations demonstrate that the designed controller guarantees the convergence of both the observation error and the position tracking error within a fixed time period, regardless of the initial EHS states. Furthermore, the network communication resources of the EHS are saved while the system stability and satisfactory tracking performance are guaranteed. Finally, the effectiveness of the proposed controller is verified by the simulation results and experimental results.