The Study On Servo Control Research For The Lower Limb Power Assist Exoskeleton Robot

The low limb wearable power assist exoskeleton robot is a kind of mechanical and electrical integration device connected in parallel to the human body,which can increase the human body parts strength and reduce blood oxygen consumption.The wearable power assist exoskeleton robot mainly includes the mechanical device in various parts of the body?the power plant and the sensor detection device three parts.They form an auxiliary robot system which can enhance the human body's movement function and the load capacity.The system combines the key technologies of sensing,control,human-computer interaction,mobile computing and other multidisciplinary areas,which accurately identify the body's motion intention and design the control system to achieve exoskeleton lower limb joint help is the focus of the study in this paper.The paper has carried on the thorough research to the follow-up control system of the lower limb wearable robot as the carrier.The main contents include the collection of lower limb movement information and processing?kinematics and dynamics modeling analysis?follow-up control system simulation?the design of hardware and software and the prototype experiment.Firstly,the theoretical analysis of the human body's lower limb structure and the human gait cycle is carried out,which provides the theoretical basis for the trajectory calculation of the follow-up limb model.With the existing powered exoskeleton double joint mechanical structure and the overall control framework as the foundation,the human lower limb signal acquisition system and the motion intention prediction algorithm based on Kalman filter,the prediction results are used as the input of dynamic analysis and the control system.The Lagrangian-Euler method is used for dynamic model of the simplified human lower limb model(two-link mechanism),the feasibility and accuracy of dynamic model and the design of the prediction algorithm are verified.The coordinate transformation matrix is established according to the traditional D-H matrix method.The information of the right and the reverse motion of the lower limbs is deduced.In order to provide the data support for realizing the gait control,the realationship is established between the joint angle variable and the robot gait trajectory data.The speed and position double closed-loop control system of the lower limb exoskeleton robot model obtained by Simulink and SimMechanics toolbox in MATLAB is used to verify the feasibility and correctness of the established lower limb model and the control system.Finally,the control system isdesigned on the basis of the modular mechanical structure of the task group,and the hardware system of the control system is selected and the distributed software system is designed.A prototype experiment platform is built to verify the effectiveness of the system.