Position Tracking Control for Pneumatic Servo System Subject to State Constraints and Voltage Saturation

Since the constraints of the rod position and velocity of pneumatic servo system (PSS) should be considered in real applications, a finite-time adaptive fuzzy tracking control based on state observer is studied for a PSS subject to input voltage saturation and full-state constraints. First, a state observer is constructed by the fuzzy logic system (FLS) to estimate the unmeasurable rod velocity through the displacement sensor signal. Then, by the utilization of the backstepping scheme and FLS, the output-feedback stabilization controller is constructed to ensure the control performance of the PSS, in which the barrier Lyapunov functions are employed to handle the constraints of the rod position and velocity. Furthermore, it is proved that the finite-time convergence of the rod position tracking error is guaranteed, all the signals in the closed-loop PSS are bounded, and rod position and velocity are not transgressed their constrained sets. Finally, the experimental results show that the proposed algorithm improves the control precision and response speed.