Finite-time Control Strategy for Electro-hydraulic Servo Systems Considering Output Constraints

A finite-time control method based on the barrier Lyapunov function is proposed for the output constraints and external load disturbances existing in the steam turbine electro-hydraulic servo system. Firstly, the barrier Lyapunov function with constraint boundary is constructed, and the problem that the output of the system may be destroyed, leading to performance degradation, is solved by the parameter setting of the boundary function. Secondly, a finite-time controller is designed based on the finite-time control theory and combined with the backstepping construction method to solve the influence of disturbances on the stability and tracking accuracy of the system in the steam turbine electro-hydraulic servo system, and the finite-time stability of the closed-loop system is proved by stability analysis. Finally, the simulation results show that for an electro-hydraulic servo system with output constraints, the control strategy proposed in this paper allows the system's position output to quickly track the desired trajectory in a short period. The barrier Lyapunov function can make the system output satisfy the constraints, and the finite-time controller based on the barrier Lyapunov function can make the system track the upper desired trajectory quickly and accurately with strong robustness.