Research On Joint Integrated Driving System Of Lower Limb Exoskeleton Robot

In order to solve the problem of assisting mobility for the elderly and the icapped,combined with the increasingly mature robotics technology,a wearable lower extremity exoskeleton robot device has been developed to assist in the recovery of the body functions of patients with walking disabilities.This article relies on Jiangsu Province's industrial foresight and common key technology key projects: Research and development of key technologies for agility to help the elderly and disabled exoskeleton robots.Carried out relevant research on lower extremity exoskeleton robots:First,completing the configuration of the joint degrees of freedom of the lower limb exoskeleton robot and the basic parameters of the lower limb mechanism.Designing the exoskeleton flexible drive joint of the string-type elastic drive,and select the main components of the drive module.Drawing lessons from traditional rigid exoskeleton,and carry out the research on the mechanism of the exoskeleton robot's waist,back,legs,feet and other flexible supports and flexible linkages.Based on the 3D model of the main supporting parts,combined with the material properties of various materials and Solidworks Simulation is used to complete the mechanical performance check of the main supporting parts.Completing the design of the overall virtual prototype of the robot,and perform the Adams motion simulation simulation of the human gait.Second,analyzing the robot model of lower extremity exoskeleton.The model adopts a two-link model simplified from the mechanical structure of a lower extremity exoskeleton robot,combined with Matlab's Robotic Toolbox to perform the forward and inverse kinematics solution to obtain the relationship between the end point of the robot and the joint angle.The simulation results are in line with human gait habits.The dynamics of the lower limb exoskeleton robot adopts the Lagrangian method to analyze the kinetic energy and potential energy of the system,and find the torque required to drive each joint.Step switching adopts a machine learning algorithm based on logistic regression,which establishes a foundation for the subsequent research on the control system of the lower extremity exoskeleton robot.Third,a distributed control system based on CAN bus was designed to build the overall control framework of the lower extremity exoskeleton robot.According to the overall plan of the control system,a complete control system hardware platform of the lower limb exoskeleton robot is constructed from the host computer,sensors and motion control modules.Combining the characteristics of lower limb movement in practical applications,design a power-assisted control mode to complete the creation of the interactive channel of the man-machine control system.Designing a minimum force control algorithm based on the impedance control principle.Setting up joint experiment platform for electric drive joints.The design of the current loop,speed loop and position loop of the servo controller is completed on the basis of PID control principle.Carring out the PID adjustment of the electric drive joint,and complete the three-loop setting of the electric drive joint.Fourth,carring out the integration of the lower limb exoskeleton robot system.An experimental prototype of the lower extremity exoskeleton robot was developed and the mechanical performance of the prototype was evaluated and verified.Relying on the developed lower extremity exoskeleton robot experimental prototype as a platform,the wearer completed a typical motion test test and a boost effect test.Evaluating the motion characteristics and working performance of the prototype and verifing the theoretical research results.Carring out a lower limb exoskeleton robot wearing experiment,and analyze the power efficiency before and after wearing.Fifth,drawing conclusions through related experiments.Lower extremity exoskeleton robot system when the torque sensor,a magnetic encoder follower body movement,there is no significant impact.With the change of the position signal,the torque sensor produces a sudden torque change during gait switching.Most of the time,the torque value is zero,which proves that the control algorithm based on the principle of minimum force has a significant boost effect.Analyzing the torque and acceleration cycle curves of slow walking and fast walking modes,the average peak torque of slow walking assist is 15.3N.m,and the average peak torque of fast walking assist is 18.2N.m.The motor follows the torque sensor for 0.02 s,which meets the actual needs of exoskeleton assisted walking.After the exoskeleton robot is worn,the heart rate is reduced by 1% to 7%,and the fast walking mode is more obvious than the slow walking mode.