The simulation and movement errors analysis of wire-driven rehabilitative robots

摘要

Wire-driven rehabilitative robots have good compliance and meet safety requirements in man-machine cooperation systems.Through wire traction control,pelvic motion is coordinated with the movement of the lower gait,improving the robotic trainer's stability.To effectively produce the training effect,the system needs to ensure accuracy of pelvis movement.So the factors affecting the motion accuracy were analyzed,including wire elasticity and the radius of wire-across-wheel.According to the wire-driven rehabilitative robot model,the expression of wire tension was built up,both the forward and inverse kinematics and dynamics equations were derived.The influence of wire tensile stiffness on the accuracy of movement of the pelvis was analyzed.The influence of the wire-across-wheel radius on the movement accuracy of the pelvis was shown through wire changes in various positions using MATLAB modeling simulation.Two factors that affect the motion accuracy were analyzed and the corresponding method for improving the accuracy was proposed.It was found that the acceleration error on the vertical axis is influenced by the outside force.The analysis gives an engineering basis for control and is universally applicable to other wire-driven systems.