氣壓肌肉致動雙軸封閉式平行機構機械臂之設計及控制

Abstract

本論文旨在研究氣壓肌肉致動器在氣壓伺服控制系統上的應用，為了解氣壓肌肉 致動器的特性，首先設計單軸之雙氣壓肌肉致動器的實驗系統，進行位置軌跡定位及軌跡追蹤的模擬及實驗。再進一步，建立兩組左右各一對氣壓肌肉致動器驅動的封閉式平行機構機械臂實驗系統，機構設計上用兩根氣壓肌肉致動器，構成一個轉動關節，經由一個收縮，另一個伸長所產生的長度變化及收縮力變化，使機械臂的上擺臂關節轉動藉以帶動下擺臂末端端點之位移，並透過控制左右角度來進行端點的位置定位控制。 在控制器設計上，先將兩系統的數學模型降階簡化為三階的非線性時變系統，且滿足匹配條件並以函數近似法為基礎之適應性滑動模式控制之軌跡控制，採用函數近似法近似系統數學模型可，處理原本難以鑑別出的系統不確定之變數及參數時變問題。此外，本文以軌跡定位的方式進行定位控制，同時兼顧暫態及穩態之特性以避免類似步階響應時所產生的震盪與超越量。 本文先以電腦模擬驗證控制器可行性，最後以實驗實現，包含單軸之雙氣壓肌肉致動器系統軌跡追蹤控制，封閉式平行雙氣壓肌肉致動器驅動機械臂系統角度與端點之定位及軌跡追蹤控制，並得到良好的追蹤結果。

This study aims to investigate the pneumatic muscle actuators (PMA) applied in the pneumatic servo system. In order to figure out the characteristics of PMA, we first design a single-axial PMA system with two PMAs for path-tracking control. Finally, a dual-axial PMAs parallel robotic arm is developed for rotational angle control and end-point path-position control. The rotation of joint is driven by dual PMAs, which means one is in extension another is in contraction. By controlling these two angles, we can control the terminal point position of the robot arm. In order to control these systems, Fourier series-based adaptive sliding mode controller is used to control the PMAs through the pressure servo valves. For ensuring the smooth motion, the path-position control is chosen to give consideration to transient and steady state response. The simulation and experiment for path-tracking control of single-axial PMAs system and the dual-axial PMAs robotic arm are executed and show that the system can have good tracking performance.