可變剛性機械手臂之設計與實作

本文研究主要為設計可變剛性機構與輕量型關節式機械手臂設計。可變剛性機構為改變手臂的剛性，其機構能獨立控制各節手臂的剛性，此機構是以槓桿原理為基礎，使用RC伺服馬達做位置控制，改變桿長來實施剛度的改變，而槓桿原理所輸出的力則以兩個彈簧元件做吸收，此設計可減少大量的使用感測元件，並減少不可預期的外力所帶來的傷害。輕量型關節式機械手臂，使用蝸桿蝸輪1:40高齒輪比設計，能提高機械手臂負重、本研究中之蝸桿蝸輪亦有自鎖功能，減少步進馬達的滑步問題，機械手臂外殼則使用1mm鈑金件，其設計能保有手臂該有的強度剛性和負重，亦能減少大部分手臂重量的問題。本機械手臂控制程式以LabVIEW2014做編譯，以簡化程式編譯流程，並進行碰撞與運動學測試。

關鍵字

可變剛性；順應性致動器；剛性控制；可變剛性致動器；軟性機器人

並列摘要

The main purpose of this paper is to design a variable stiffness mechanism and a lightweight articulated robot arm. The variable stiffness mechanism is used to modify the stiffness of the robot arm to minimize large forces due to shocks, to safely interact with the user, and the ability to store and release energy in passive elastic elements. Such variable stiffness mechanism design is based on lever kinematics. Moreover, RC servo motor is used to manipulate the link length to adjust the stiffness for position control purposes. The output force from the lever is absorbed by two spring elements. Such design can reduce the use of a large number of sensing elements and lessen the damage caused by unpredictable external forces. The designed articulated robotic arm uses a 1:40 high gear ratio by worm gear to increase the payload capacity and decrease the weight of the robot arm. The worm gear also has a self-locking function, which reduces the sliding step of the stepping motor. The robot arm is fabricated by 1 mm thickness sheet metal. The advantages of the design presented in this thesis is retained the strength and loading capacity of the robot arm. It can also reduce the weight of the robot arms. The software package LabVIEW 2014 is introduced to build the control and measurement environment. Several experimental results confirm that such design is reliable and possesses low implementation cost for shock test.