STATICS AND STIFFNESS STUDY ON A 3-DOF PARALLEL WIRE DRIVEN FLEXIBLE MANIPULATOR

SUI Chunping  ZHAO Mingyang

(Robotics Laboratory, Shenyang Institute of Automation, Chinese Academy of Sciences,Shenyang 110016)

Abstract: A 3-DOF parallel wire driven stiffness-variable manipulator is presented by making use of the elasticity of wires and the redundant actuation. Based on static and stiffness analysis, the study on stiffness control is made. Firstly, by projecting the tension of wires into the joint space, the relation between joint forces and tension of wires and that between joint forces and resultant forces are studied, and a 3 dimension force vector closure theory is presented. Then, the joint stiffness matrix and the manipulating stiffness matrix are deduced according to differential transform theory, and a numerical example is given subsequently. The result shows that the stiffness relates not only to stiffness of wires but also to tension of wires. So it can be changed by regulating the tension of wires. Finally, stiffness control to this stiffness-variable manipulator is studied by separating position control and tension control, and a numerical example is done for verifying it.

Key words: Parallel wire driven  Force vector closure  Differential transformation Stiffness-variable  Stiffness control

CLC No: TP24

国家自然科学基金资助项目(50275143). Received 20050601, received in revised form  20051226