差动驱动机械手结构设计及抓取形态研究

Structural design and grasping morphology study of differential drive manipulator

为了解决传统欠驱动机械手仅能被动适应抓取物体形态的问题,提出了一种基于绳索与形状记忆合金(SMA)弹簧的差动驱动机械手,可以根据被抓取物体特征主动控制手指的抓取形态,更符合人类手部的抓握特点。采用D-H法建立手指的运动学模型,分析了手指的工作空间;根据力矩平衡原理建立了机械手的静力学模型,阐明了驱动绳索的驱动力、手指关节等效刚度对抓取形态的影响规律,并通过ADAMS仿真对理论分析结果进行验证;最后,对样机进行试验测试,研究结果表明,根据物体的轮廓大小,通过主动控制机械手绳索驱动力与手指关节的等效刚度,可以完成包络、捏取等典型的抓取动作,进而实现对不同形状、尺寸物体的稳定抓取。

In order to solve the problem that traditional underdriven manipulators can only passively adapt to the morphology of grasping objects,a rope and Shape Memory Alloy(SMA)spring-based differential drive manipulator was proposed,which can actively control the grasping morphology of the fingers according to the characteristics of the objects to be grasped,and is more in line with the grasping characteristics of the human hand.The kinematic model of the finger was developed using the D-H method and the workspace of the finger was analyzed;the static mechanical model of the manipulator was established according to the principle of moment equilibrium,and the influence laws of the driving force of the drive rope and the equivalent stiffness of the finger joints on the grasping pattern were elucidated,and the results of the theoretical analysis were verified by ADAMS simulation;finally,the prototype was tested experimentally,and the research results show that according to the contour size of the object,the typical grasping actions such as enveloping and pinching can be accomplished by actively controlling the driving force of the drive rope and the equivalent stiffness of the finger joints,so as to realize the stable grasping of objects of different shapes and sizes.