Research On Wire-driven Parallel Rehabilitation Robot

In recent years, rehabilitation robots as an emerging robot are developed quickly. They coulddrive the limb with thousands of repetitive movement though the machine in order to irritate andrebuild the motor nerve system and restore limb function exercise, which the function-barrier patientand the elder’s quality of life are improved. This paper introduces a parallel rehabilitative robot drivenby cable which is proposed after full study of the law of the human pelvic motion. The main works inthis paper are as follow：The law of the normal human pelvic motion during the course of gait is analyzed and the types ofpelvis’s degree of freedom are established. The parallel robot is designed based on the types ofpelvis’s degree of freedom. Through the wire-driven parallel robot，the coordinated motion betweenthe body trunk and the lower limbs is realized and certain external force is alse got，which can makenot only the trainer carry on the weight relief training but also exercise self-balance ability training，thus the better training effect can be achieved.The inverse and forward kinematic models of the wire-driven parallel robot are established bythe closed-vector quadrilateral method and Newton-Raphson iterative method. Through theestablishment of the kinematics equations, the relationship between wire’s motion and pelvis’s motionwas obtained. The trajectory of pelvic motion is planned. And the wire’s variation of length, velocityand acceleration is simulated.The parallel robot’s static wrench balance equations are established. And the working space ofthe wire-driven parallel robot is drawn using Monte-Carlo method. The dynamic models of themoving platform, the drive and the whole system are established. The stiffness of the robot isanalyzed, the stiffness matrix and the homogeneous stiffness matrix are got, and the evaluation indexof the stiffness matrix is given.Based on the theoretical analysis and numerical simulation above, the structure, drive model andcontrol system of the wire-driven parallel robot are designed, and the experimental platform of thewire-driven parallel rehabilitation robot is constructed. The motion along the planned trajectory hasbeen successfully controlled by the prototype.The mutual validation between the motion control testand the theory simulation indicates the configuration of the robot and the motion control scheme isfeasible.