氣壓伺服系統具時變及高度非線性,不易得到準確之數學模式進行滑動模式控制器設計,本文旨在發展具H(下標∞)追蹤及函式近似法之適應性滑動模式控制器,實現氣壓伺服系統之軌跡追蹤控制,本控制器以Fourier級數之函式近似法估測未知函數,故可省略精確之數學模式,以H(下標∞)追蹤結合適應性滑動模式控制器,可使控制器避免估測誤差、未考慮到之動態及干擾所造成之影響,因此,無需數學模式及試誤法進行控制器設計及估測函式選擇。以Lyapunov函數進行穩定性分析。此外,本文所發展之控制器可藉由H(下標∞)追蹤控制器改善滑動模式控制器之嚴重不連續振顫問題。最後,本文以實驗驗證所發展之具H(下標∞)追蹤及函式近似法之適應性滑動模式控制器,實現於無桿氣壓缸組成之氣壓伺服系統的軌跡追蹤控制。
It's difficult for pneumatic actuator systems to fit into an accurate dynamic model for model-based sliding-mode control design because of the nonlinear and time-varying characteristics. The objective of this research is to develop a new H(subscript ∞) tracking-based adaptive sliding-mode controller for nonlinear pneumatic actuator systems. The controller initially uses a Fourier series-based functional approximation to reach an unknown function so as to circumvent the prerequisites of the models. The H(subscript ∞) tracking technique can then be incorporated into an adaptive sliding-mode control method to protect the derived controller from approximated errors, un-modeled dynamics and disturbances. Thus, system dynamic models are not necessary for achieving the proposed controller design with H(subscript ∞) tracking performance and trial-and-error is not required to select an approximation function. System stability is ensured through the new laws for the coefficients of the Fourier-series functions which are derived from a Lyapunov function. In addition, the serious chattering problem can be reduced through the projected H(subscript∞)tracking-based adaptive sliding-mode controller control method by means of the H(subscript∞) tracking controller in comparison with the Fourier series-based adaptive sliding-mode controller. Consequently, the practical experiments on a rodless pneumatic servo system are successfully implemented with different path tracking profiles, which validates the proposed method.