Research On The Design And Control Strategy Of The Force-increasing Upper Extremity Exoskeleton Interactive System

In recent years,science and technology have developed rapidly,a device for enhancing human body function and exercise assist has been born with intelligent technology.The upper limb exoskeleton,combined with artificial intelligence on the basis of robot technology,can provide a variety of functional support for the wearer,with strong research value and significance.However,in the research of force-enhancing upper limb exoskeleton,interactive system design and controller design still need to be developed.This paper analyzes and establishes the interactive system and controller of the force-enhancing upper limb exoskeleton.Firstly,in order to adapt to different arm lengths,a mechanical structure with adjustable dimensions is designed based on the analysis of the range of upper limb movement.Then,in order to study the muscle force supply during the upper limb movement,a simplified model of upper limb skeletal muscle is deduced and established.A virtual prototype of human-computer interaction is established,and an interactive force controller based on adaptive impedance model is designed.Finally,a compensator is introduced to achieve the effect of boosting assistance.The main research contents are as follows:(1)Based on the study of exoskeleton in upper limb,a 6-DOF force-enhanced exoskeleton structure is designed.The typical exoskeleton systems of upper limb at home and abroad are analyzed and summarized,and the driver of exoskeleton and the controller of human-computer interaction are studied.On this basis,the configuration of the upper limb exoskeleton degrees of freedom,the design of mechanical structure and the selection of drivers are carried out.(2)In order to study the supply of muscle force during upper limb movement,an upper limb skeletal muscle model based on Hill model is established.Based on the analysis of the physiological structure of the human upper limb,the driving moment of the shoulder joint and the muscle during the flexion and extension of the elbow joint of the human upper limb is derived and established.The model simulation is carried out on the basis of MATLAB.(3)By analyzing the upper limb exoskeleton model,an adjustable virtual prototype of human-computer interaction is designed.The positive kinematics,inverse kinematics,and dynamics models of upper limb exoskeleton are derived,and a 3D virtual prototype of the exoskeleton is established in SolidWorks: in order to adapt to different lengths of people's arms,an adjustable part is established and imported through the plug-in.MATLAB provides the basis for the subsequent co-simulation;the human-computer interaction model is established,that is,the upper limb model is created in SolidWorks,and the spring damping system is used to obtain the interaction force according to the position difference between the upper limb and the exoskeleton.(4)In order to solve the problem of end force enhancement of upper limb,Based on the position-based impedance model interactive force controller,a model free control based on PSO optimization neural network compensation(PSO-MFNNC)is designed for trajectory tracking.Firstly,analyze the selected position-based impedance model to derive position correction.Then,for the complexity of impedance parameter selection,fuzzy controller is designed to realize online adjustment of parameters.For the trajectory tracking part,a modelless controller based on time delay estimation neural network compensation is introduced,and using PSO algorithm to optimize parameters makes the selection of neural network parameters simpler.Finally,the external interference compensation and gravity compensation module are added to improve the control performance of the system and make the controller more intelligent.(5)The interactive force controller based on adaptive impedance model is simulated and optimized in MATLAB.Under the human-computer interaction model,the MFNNC and PSO-MFNNC control methods are simulated and compared,and the effectiveness of the external interference compensator is verified.In response to the influence of the exoskeleton on the system,a gravity compensator is added to achieve gravity compensation.As the load increases,the system tracking error and human-computer interaction force will also increase.Therefore,the load compensator is introduced in the controller design,and the simulation results show that the tracking effect is optimized.