Design And Control Of Hip Exoskeleton Based On Series Elastic Actuator

With the increase of strokes and fractures in the aging population,which easily cause lower limb and limb dysfunction,the demand for sports rehabilitation medicine continues to increase.The lower extremity exoskeleton robot,as a human-machine coupled mechatronics system,provides motor function rehabilitation training for patients with lower limb limb dysfunction by simulating the walking gait of normal people.Colleges and scientific research institutions at home and abroad have conducted a lot of research on it,but most of them use rigid driving,which has insufficient flexibility and brings safety problems.Therefore,this article designs a hip exoskeleton based on a compliant serial elastic drive,and on this basis,system modeling,building a control system,designing control algorithms and using experiments to verify.The main research contents and results of this article are as follows:Based on the anatomical structure and kinematics of the hip joint,the gait of the human body is analyzed,and the exoskeleton structure of the hip joint is designed.The freedom setting and range of motion of the hip exoskeleton were determined,and the joint size design and drive system selection were completed.In order to improve the safety of the interaction between the hip joint exoskeleton and the human,the joint is designed with a series of elastic drives to construct a three-dimensional model of the hip joint exoskeleton and select suitable processing materials.According to the hip joint exoskeleton model,system modeling and performance analysis are carried out.In order to obtain the relationship between the trajectory of the human body and the driving angle of the hip joint,a forward and inverse kinematics analysis is performed.In order to compensate for the torque of the hip joint,the relationship between the human contact force and the driving torque of the hip joint is understood,and the dynamic analysis is performed.Establish a human-machine interaction model of the serial elastic drive and human body,analyze the performance of the serial elastic drive,and confirm that it meets the design requirements.The closed-loop control model of the series elastic actuator is constructed,and the human disturbance is substituted into its performance analysis to obtain the influence of the human disturbance on the system.To ensure the effectiveness of rehabilitation training,the control system adopted active and passive control training strategies.According to the requirements of the overall framework of the control system,the design of the hip exoskeleton control system was completed.Design,select,connect and debug the hardware of the control system.The control system software adopts human-computer interaction interface design,and introduces its use process and internal motion mode control.According to the three-dimensional model of the hip exoskeleton,an experimental platform for the hip exoskeleton was built,and for the trajectory tracking control,the fuzzy impedance control algorithm of the exoskeleton was designed.The genetic factor least squares method was used to estimate the lower limb parameters of the human body,and the fuzzy controller was used to externally The bone impedance model parameters are compensated.Using extended Kalman filtering,the parameter identification of the friction model of the hip exoskeleton is completed,the damping coefficient and the Coulomb friction coefficient are obtained,and the friction compensation is performed.Completed basic functional experiment,human gait measurement experiment and rehabilitation exercise training experiment.The experimental results show that the hip exoskeleton is more comfortable to wear,the structure design is reasonable,the control system software and hardware work normally,and the fuzzy impedance algorithm can better track the reference gait trajectory of human body measurement than the impedance control.