Dynamic surface control of bellows-driven ultra-precision positioning system based on nonlinear extended state observer

Abstract

This thesis report on a novel bellows-driven, two-dimensional, pneumatic ultra-precise positioning system. A dynamic surface control (DSC) method based on nonlinear extended state observer (NESO) is proposed to solve the control problem of nonlinear pneumatic servo positioning system. The bellows are used as actuators and the mathematical model is established according to the dynamic characteristic equation of the system. Considering the unknown state signal of two-dimensional pneumatic servo system, a fourth-order NESO is developed to conquer these problems. Dynamic surface control is adopted to eliminate the problem of differential expansion and simplify the design of controller and parameters. Afterwards, the selection of suitable Lyapunov's function proves that all signals of the system are bounded Furthermore, through practical application, the control method proposed in this paper guarantees the asymptotic stability of the pneumatic two-dimensional ultra-precision servo positioning system and the requirement of ultra-precision with large stroke and ultra-precise is realized.