本論文研究的重點在於了解新型致動材料的特性，本文經分析比較後，最後選用形狀記憶合金做為致動器，並依照狀記憶合金的特性設計出能夠模仿人類手指運動的夾爪機構。而後搭配馬達依照人體手肘至手腕關節的運動形式，設計機械手臂。為了解物件與機械手臂的座標轉換關係，利用Denavit-Hartenberg法則，推導座標的正轉換與逆轉換。 機械手臂的控制，可將其分成馬達的控制與夾爪的控制。馬達的控制主要是利用PC編輯馬達動作而後寫入RS-232，利用RS-232對馬達控制。為了解何種的加熱方式對於夾爪所用之形狀記憶合金有較佳的控制表現，因而對形狀記憶合金使用PWM加熱與直接通電加熱進行實體測試。 本論文所設計的機械手臂活動範圍，除了手肘關節的活動範圍無法與人類手臂的活動範圍相仿外，其他關節的活動皆能夠與人類手臂的動作相似，不論是在手臂的旋前、旋後，手腕的外展、內收和手指挾持物件的動作皆有不錯的表現。而在形狀記憶合金的加熱上，利用PWM的加熱方式，能對形狀記憶合金有較均勻的加熱，使得形狀記憶合金的夾爪機構在分離時，較不會有殘餘應變產生。 The purpose of this thesis is to design a two-finger prosthetic hand by using smart material for actuating the motion of the fingers. After surveying the characteristics of different smart materials, shape memory alloy (SMA) is chosen for its large displacement. The motion design of the prosthetic hand is based on the movement of the human hand. The other joints except fingers of the prosthetic hand are actuated by motors. In the thesis, the kinematics of the prosthetic hand is analyzed by Denavit-Hartenberg principle. The designed prosthetic hand arm can perform the movement similar to a human hand. To control the movement of the two-finger prosthetic hand, different methods are adopted for the hand and the fingers. PC code is written and then downloads to RS-232 board to control the motors for the hand motion. The shape memory alloy dominates the finger motion is controlled by using a simple switch and PWM heating process.
