Research On The Configuration And Control Of A Cable-driven Body-weight Support Gait Training Robot

In this paper,a cable-driven body-weight support gait training robot(BWSGTR)is designed to meet the realistic needs of patients with lower limb motor dysfunction for body-weight support gait training.It can simulate the normal gait trajectory and the movement law of the center of gravity of the human body,and provide patients with partial body gravity support and a suitable and stable walking driving force.At the same time,it can help patients in different rehabilitation stages to carry out passive training and active training through two control methods of position servo and force servo composite control.The research contents of this paper include:(1)The overall configuration of the cable-driven BWSGTR.Firstly,by analyzing the walking process of the human body,the gait trajectory and the movement law of the center of gravity of the human body during normal walking are obtained.Secondly,Considering the clinical requirements for body-weight support gait training,the overall configuration and hierarchical control scheme of the BWSGTR are determined by analyzing the type of cable parallel mechanism and the traction mode.Finally,for patients in different rehabilitation stages,the position-servo compound control and force-servo compound control are proposed for passive training and active training.(2)Modeling and Simulation of the cable-driven BWSGTR.Firstly,the kinematic analysis of the mathematical model of the BWSGTR are carried out by the VectorAlgebra method,and the displacement of each cable during the gait training of the patient is calculated.Secondly,the dynamic model of the BWSGTR is established by the Newton-Euler method,and the pulling force of each cable during the patient’s gait training is calculated.Finally,based on the S-shaped velocity curve,the motion planning of the BWSGTR is carried out with a time-phase distribution relationship,and the change curves of the displacement,velocity and acceleration of each cable are obtained,which are used as the input signal of the subsequent control system.(3)Research on the control strategy of the cable-driven BWSGTR.Firstly,taking the drive unit of the BWSGTR as the research object,the mathematical model of the drive unit of the system is established by the mechanism analysis method.Secondly,by analyzing the dynamic characteristics of the forward channel transfer function of the system,the position-servo compound control strategy and the force-servo compound control strategy are designed.Finally,the simulation analysis verifies that the designed composite control strategy of position servo and force servo can meet the response requirements of the system both in speediness and stability to the loading command.