Research On Active And Passive Exoskeleton Robot System With Lower Limbs

The lower limb assisted exoskeleton robot is a wearable robot that realizes motion control through human-computer interaction,which can effectively improve the wearer’s motion ability.There are very important and extensive application requirements in military and national defense,medical rehabilitation,agricultural transportation,and industrial production.Active and passive lower limb assisted exoskeleton robots(hereinafter referred to as "lower limb exoskeleton")combine active driving and passive driving,which can effectively reduce overall weight,save energy,and improve the body’s weight-bearing capacity.This paper focuses on the purpose and application of lower extremity exoskeleton,and focuses on key technical issues such as wearable mechanical structure design,motion perception system construction,and human-computer interactive motion control.The paper uses theoretical analysis,simulation analysis,and physical experiments.The research is carried out from the following four aspects.(1)The structure optimization and improvement design of the lower limb exoskeleton system,the design of the passive ankle joint assist mechanism,the stress analysis,the motion simulation analysis and the assist effect analysis on it,the physical processing and the integral assembly with the lower limb exoskeleton.In order to better realize the human-computer interactive movement follow-up control,a plantar pressure detection device and a human movement information collection device are designed.(2)The kinematics modeling of the exoskeleton system of the lower extremity was carried out,and the relationship between the end coordinates of the exoskeleton of the lower extremity and the joint angle was obtained.Using the Lagrange dynamic modeling method,the relationship between the joint angle and the driving torque of the exoskeleton of the lower extremity was obtained.The relationship between the two provides a basis for the design of the subsequent control system.(3)Research on the control strategy of lower extremity exoskeleton,considering model information and parameter perturbation,respectively design PD control based on model compensation and sliding mode control based on model compensation,which improves the accuracy of following control.The lower extremity exoskeleton dynamic model is inaccurate and has its own gravity and external interaction disturbances.A sliding mode control based on uncertainty and disturbance estimation is designed to achieve high-precision follow-up control of the system.(4)Perform experimental research on the exoskeleton of the lower limbs,complete the periodic motion experiment of the joints of the lower limbs,and on this basis complete the level walking experiment,the up and down slope walking experiment,the up and down stairs experiment and the lower limb joint flexibility experiment.Verify the motion following control effect and boosting effect of the lower extremity exoskeleton system,and meet the design indicators.