Development Of Lower Limb Rehabilitation Exoskeleton And Research On Control Method Based On Progressive Rehabilitation

This subject designed a modular and multi-posture lower limb rehabilitation exoskeleton robot aiming at the individual differences of lower limb paralysis patients,the progressive nature of movement recovery and the repetitiveness of rehabilitation process.The progressive rehabilitation training strategy and robot control method are studied according to the rehabilitation stage,and the analysis is conducted through human-machine coupled simulation and experiments.Through the analysis of human joint motion,the lower limb exoskeleton robot is integrated and modularized,including the three parts of the thigh drive unit,lumbar support unit and foot orthosis.The transmission system,drive system,control system,sensor system and distance adjustment mechanism of the core unit are designed.The exoskeleton can change the training posture through the disassembly and assembly of the connecting mechanism,and realize multiple training modes such as supine posture,sitting posture and standing posture.The progressive rehabilitation training strategy is implemented for the progressive process of patient rehabilitation.The trajectory-constrained position control,assisted torque control,and resistance training are respectively implemented in the early,middle,and late stages of rehabilitation,and training posture,position trajectory,assist ratio and resistance ratio are adjusted in real time.According to this,kinematics simulation and biomechanical simulation are performed on the limb movements in different postures of the human body,including the trajectory planning and motion simulation of sitting and lying posture and the gait analysis and motion simulation of standing posture.The Straight-line flexion and extension in the supine position,circular trajectory movement in the supine position,leg-lifting movement in the sitting position and walking in the standing position are also studied according to the rehabilitation cycle.The research on progressive rehabilitation control methods of exoskeleton robots are conducted.The kinematic and dynamic analysis on man-machine systems with different phases in sitting,lying and standing positions are also carried out.Aiming at the three modes of rehabilitation strategies,the corresponding control methods are studied.The position control of the trajectory constraint in the early stage of rehabilitation adopts the computed torque method to linearly decouple the dynamic system and uses the RBF neural network to linearly compensate the uncertainty,improving the accuracy of trajectory tracking by positon error approximation.In the mid-rehabilitation period,the power-assisted control adopts the torque control based on limb torque feedback.By adjusting the torque coefficient,the ratio of human-machine output torque can be changed to train the human muscles.At the same time,the human-machine interaction force is dynamically adjusted through the impedance control module in combination with the human-machine impedance relationship to improve the flexibility of the control.The resistance control of active confrontation in the later period of rehabilitation is based on the principle of excessive recovery,and the reverse torque is applied to the limb by adjusting the resistance coefficient.The exoskeleton simulation model and the human-machine coupled system model is established to perform system verification and control method simulation analysis using the co-simulation platform of ADAMS and Simulink.Aiming at the trajectory constraint position control and neural network adjustment,the circular trajectory movement in the supine position is taken as an example to simulate the motion process and analyze the control effect.Aiming at the power-assisted torque control and impedance relationship adjustment,the walking in the standing position is taken as an example to simulate the motion process and analyze,and the power assist effect of torque control is studied by changing the torque coefficient.Finally,the exoskeleton system experiment platform is built to complete the debugging of the control drive system and the communication system.The single joint position control experiment is conducted to verify the feasibility of the system.