以內部模型原理為基礎之控制器初始值補償及其於雙軸機械手臂之應用

Abstract

機械手臂為多關節機構，在各軸皆具有致動器，其動力模式為非線性藕合多變數系統，運用範圍涵蓋物件搬運、噴漆、點焊、弧焊等；本文針對機械手臂之定位和循軌控制，提出以內部模型原理為基礎之控制器初始值補償(Initial Value Compensation, IVC)。改善傳統內部模型為基礎之控制器會有超越量(Overshoot)或振盪(Oscillation)的問題，設計內部模型原理為基礎之控制器具有抑制已知干擾模型的優點，透過IVC之設計可降低超越量或振盪的產生，大大地提升控制器的性能。 在控制平台架構上，採用美國德州儀器公司(Texas Instruments, TI)所生產之TMS320C6713 DSP搭配具FPGA之自製擴充子板為實驗平台。在FPGA方面，以硬體描述語言(VHDL)撰寫Encoder、 A/D與D/A之界面程式；在控制器實現上，利用TI所提供的Code Composer Studio (CCS)環境下以C/C++撰寫控制器程式並下載到DSP上執行。整體控制架構經由雙軸機械手臂定位和追循圓軌跡予以驗證，其結果顯示將可有效改善暫態時產生超越量或振盪問題，以及更佳的抑制外部干擾。Robotic manipulators contain actuators in each joint, each with nonlinear, coupling and variant parameter characteristics. Arc and spot welding, spray painting, milling and drilling are some applications of robotic manipulators. For positioning and trajectory tracking control, a method uisng Internal Model Principle-based (IMP-based) controllers with the Initial Value Compensation (IVC) is proposed in this thesis. Using IVC, the overshoot and oscillation problem in the IMP-based controllers has been improved. In the experimental setup, we utilize Texas instrument's TMS320C6713 DSP with an FPGA (Field-Programmable Gate Array) as our control kernel. Implementing control laws, we employ the C/C++ language as a tool. Moreover, we establish an interface to two shaft encoders, ADCs and DACs using hardware description language (VHDL). The experimental result shows that the proposed scheme improves the tracking performance and robustness against disturbance.