Stability Control Strategy Of Multi-articular Lower Extremity Exoskeleton

Since the "Thirteenth Five-Year Plan",China has gradually become an important member of the development of the world’s intelligent robot industry,according to the "China Intelligent Robot Industry Development Status Research and Investment Prospect Forecast Report(2022-2029)" shows that China’s wearable exoskeleton robot demand will usher in a huge growth in the next decade,from the national strategic level and audience needs,the growth of demand is constantly overcoming technical difficulties.At present,wearable lower limb exoskeleton robots still face many technical problems,in order to make lower limb exoskeleton robots more comfortable,safe and stable when wearing,this paper mainly focuses on the stability of human-machine collaboration under the overall control of multijoint lower limb exoskeleton,from the aspects of lower limb exoskeleton human-computer coupling system dynamics,multi-joint synchronous control strategy and other aspects of research.The main research work of the thesis includes:(1)Motion characteristics under human-machine coupling Design of multi-joint lower limb exoskeleton.Firstly,aiming at the safety issues of structural design comfort and humancomputer interaction,the size parameters of the structure,the degree of freedom of each joint and the choice of drive mode are determined based on the analysis of the anatomy of the motion characteristics and gait cycle of each joint of the lower limb and the energy consumption of actual walking.A multi-joint lower limb exoskeleton robot model was established,the model was established based on D-H parameter method and Lagrange equation,and the moment of each joint of the lower limb exoskeleton was calculated,and the walking motion data of each joint of the lower limb exoskeleton robot was obtained,and the theoretical calculation and simulation experiment of the model were carried out through MATLAB and SIMLINK software to verify its reliability and finally for the walking stability problem;(2)Multi-joint lower extremity exoskeleton synchronous control system.Aiming at the problem of human-machine collaborative stability caused by the independent control of each joint by multi-joint lower limb exoskeleton robots at home and abroad,the relationship between angle and torque between each joint is analyzed,and an adaptive impedance controller that can synchronize the control of multi-joint lower limb exoskeleton is established,which solves the problem of synchronous control of multiple joints of the lower limb exoskeleton and the inability to accurately obtain the contact force of tracking targets in the case of unknown environment or environmental parameter changes.At the same time,the influence of controller parameter selection on the stability of the control system is analyzed;(3)SSA-BP neural network algorithm to optimize the adaptive impedance controller.Aiming at the influence of adaptive impedance controller parameter selection on system stability,a SSA-BP algorithm combining sparrow search algorithm and BP neural network is proposed to optimize the parameter selection of adaptive impedance controller,which solves the problem of long dynamic response time and large jitter of the controller,and realizes more accurate control.Finally,the physical experiment is built,the experimental scheme is designed,and the stability of the designed controller is verified.The results show that the designed controller has a good tracking effect on the multi-joint lower limb exoskeleton.This paper mainly studies the multi-joint synchronous control strategy of lower extremity exoskeleton robot and the stability control method in uncertain environment.It solves the problem of lower extremity exoskeleton control accuracy and dynamic response,and provides a new control strategy for the design of lower extremity exoskeleton rehabilitation robot.