Quasi-Adaptive Sliding Mode Motion Control of Hydraulic Servo-Mechanism With Modeling Uncertainty: A Barrier Function-Based Method

This research focuses on motion control of hydraulic servo-mechanism and presents a novel quasi-adaptive sliding mode control algorithm with barrier function-based control gain. The mathematical model of the system is established in integral series format to contribute to the controller design. The utilized sliding mode control gain is designed to be adapted with the change of design error related to tracking error. It can first increase until the design error reaches to a small domain at a designed time by utilizing constant gain. And then the control gain will automatically switch to barrier function form to hold design error within a predefined domain un-depending on the modeling uncertainties theoretically. Correspondingly, the tracking error will converge to a small domain. The system stability is proved via Lyapunov analysis. By comparing to three classic controllers with motion tracking experiments, the achievable higher tracking accuracy of the proposed new control law are validated sufficiently.