Research On Impedance Controlmethod Ofknee Jointrehabilitation Exoskeleton Based On Bodyimpedance Mapping

This topic is derived from the peacock project in Shenzhen.By the end of 2016,the number of people over the age of 60 in China had reached 240 million,accounting for 17.3 percent of the total population,making China the country with the most elderly people in the world.With the increasingly serious aging of the population in China,the number of patients with chronic diseases is also increasing.Stroke,as a high incidence among the elderly,is very likely to cause limb movement disorder,hemiplegia,paralysis and even death.In addition,due to traffic accidents,accidental injuries and changes in people’s living habits,the number of people with physical disabilities is also increasing.As the largest and most complex joint in the human body,the knee joint is frequently used and frequently injured,which plays an important role in people’s daily activities.Therefore,it is of great significance for the rehabilitation study of knee joint nerve injury.This paper aims at the training stage of muscle strengthening in patients with nerve injury,based on the serial elastic drive,designed a human-machine interactive knee rehabilitation exoskeleton robot,which frees the physical therapist from the heavy manual assistance tasks and can be adjusted according to the patient’s disability to provide patients with on-demand auxiliary rehabilitation training,encourage patients to actively participate in the rehabilitation training process,and improve the speed of rehabilitation of patients’ knee joints.Firstly,the general model of the series elastic driver is analyzed,which shows very good characteristics in the low frequency range.According to the use requirements,a tandem elastic drive is designed,and based on the tandem elastic drive,a knee rehabilitation exoskeleton robot is designed,which can be adjusted in the width direction and height direction according to the body shape of the patient to adapt to different Tall,short,thin,and crowded.Secondly,the human-computer interaction system is modeled,a nominal model controller control method is adopted,and the optimal PD control and disturbance observer control methods are comprehensively applied to the controller,so that the knee rehabilitation exoskeleton robot has the advantages of low output impedance,good human-computer interaction performance and robustness are obtained,and verified by numerical simulation.Then,according to the length of the doctor’s teaching trajectory,two teaching and learning routes are proposed,and then the knee stiffness estimation method is introduced.The variable stiffness assisted control scheme of the knee rehabilitationexoskeleton robot is designed using impedance control to achieve the patient provide assistance on demand.Finally,a simulation experiment on the knee joint exoskeleton with variable stiffness was carried out to verify the effectiveness of the scheme,and a simulation experiment on the skill generalization of the knee joint rehabilitation exoskeleton robot was further carried out.It is found that by combining different position trajectories and different stiffness trajectories,the knee rehabilitation exoskeleton robot can meet different task needs,so that it is not necessary for the doctor to repeatedly teach it.