The Design Of Bionic Arm And Fingers Driven By Smart Materials

In this thesis, humanoid arm is the research emphasis, which contains two parts: fewer Degree Of Freedom(DOF) Bionic arm and hand dexterity with 14 degrees of freedom. Dexterous hands are Bionic arm’s end effector, which affects the performance level of the system, flexibility and fine operation. Therefore, this paper designed research focusing on dexterous hand. We used shape memory alloy wire and fluidic muscle to drive Bionic arm, the final design of humanoid arm have some characteristics of lightweight, dexterity, flexibility and others, it can grip at most 0.5kg everyday items such as cups, meal cards, coins etc.I analyzed the angle range of each joint motion and the angular velocity range of conventional motion to guide the Bionic arm design,by using motion capture systems to collect the motion data of human arm wrist, elbow and shoulder.The new lightweight dexterous hand has the characteristic of modular, integrated, high power to weight ratio and flexibility. It is consists of five fingers and the palm, and have 14 degrees of freedom. There is an angle feedback on each joint of finger and a pressure feedback on each fingertip. Because of using of a rope drive, the transmission efficiency is pretty high.Instead of motor, I choose the nickel-titanium shape memory alloy and fluidic muscle to drive the hand, which is flexibility, and high power to weight ratio. Shape memory alloy was used to drive each joint of the fingers and fluidic muscle was used to drive the wrist and elbow joints. For the purchased memory alloy and fluidic muscle, I did some mechanical properties experiment on the memory alloy and fluidic muscle, and verified the rationality of the design. After making the prototype of dexterous hands, I built an experimental platform, and completed dexterous hand test of griping everyday objects.