基于形状记忆合金的仿生假手设计

Bionic Design of Prosthetic Hand Based on Shape Memory Alloy

摘要: 目前假肢手大多由电机驱动，其体积大、质量大不够便携，为此本文设计了一种基于形状记忆合金驱动的模块化仿生手，整体质量为188 g，每根手指可独立驱动控制。通过滑轮组绕线的方式增大SMA丝的有效长度。绘制了假肢手的三维模型并对手指7连杆机构进行运动学分析及仿真，利用MATLAB验证了其关节角度和指尖轨迹曲线，以STM32单片机作为控制器结合多传感器设计了控制系统。并通过实验验证假手指的运动状态，结果表明，SMA驱动器的输出位移可以达到假手指所需的驱动行程，假手指的指尖轨迹与理论值相符合，可以达到设计的预期目标。研究结果解决了SMA驱动位移较小的问题，为形状记忆合金材料作为仿生假手的新型驱动器以及仿生手的机械结构提供了设计思路。

Abstract: Since most prosthetic hands are actuated by motors, which are large, heavy, and difficult to carry, this paper designs a modular SMA-actuators bionic prosthetic hand. Its quality is 188 g in total. Each finger can be actuated and controlled independently. By coiling with a pulley block, it increas-es the effective length of the SMA wire. A 3D model of the prosthetic hand is drawn, and kinematics analysis and simulation of the seven-link mechanism are carried out. Using MATLAB, this paper verifies the joint range of motion and kinematic trajectories of the fingertip. The control system is designed by taking STM32 as the controller and combing it with a multi-sensor. Through experi-ments, the motion state of the artificial finger is verified. According to the results, the output dis-placement of the SMA actuator can meet the driving distance requirements of the artificial finger, and the kinematic trajectories of the fingertip are consistent with the theoretical value which can achieve the expected goal of design. The research solves the problem of short actuated displace-ment of SMA and provides a design idea for using SMA as a new actuator and the mechanical struc-ture of bionic prosthetic hands.