Study On Hysteresis Resistance Modeling And Control Techniques Of Lower Extremity Exoskeleton Joints

Space exoskeleton auxiliary system mainly use the mechanical structure,sensor information,control system,the development of new energy and new materials technology,build an astronaut movement and operation support system,it can take the initiative to perception and obtain an astronaut motions and movement trend,improve the astronaut extravehicular activity ability in the surface of the moon.The exoskeleton lunar booster suit is designed to enable astronauts to better complete the lunar surface walk,transport cargo and other work outside the capsule.The purpose of this paper is to study the problem of extravetical spacesuit-astronaut lower limb system so that astronauts can move more conveniently on the lunar surface in the future and accomplish various lunar surface missions.(1)From the perspective of human physiological structure,the walking gait of human lower limbs and the composition of each joint were studied.Some typical missions of astronauts under the low gravity environment of lunar surface are analyzed,and the degree of freedom required for lower limb joints is determined according to the missions.The selection of motor drive for lower limb joints is also carried out.Some hardware of the exoskeleton test platform is briefly introduced.(2)The d-H parameter method was used to analyze the kinematics of human lower limbs,and the validity of forward kinematics and inverse kinematics was verified by Simulink module in MATLAB.The Preisach model is introduced in detail,the singlejoint resistance moment measurement method is studied,the charging rod model is established to measure the single-joint damping moment,and finally the hysteresis damping moment diagram of the astronaut's lower limb hip and knee is obtained.The results show that the lower limb joint resistance of the space suit has great resistance to the astronaut in one gait cycle.Through this research,the dynamic constraint of space suit hysteresis resistance is introduced,which can provide an important theoretical basis for the implementation of space suit exoskeleton control in the future.(3)first introduced the dynamic modeling method and characteristics of several common,and the lower limb exoskeleton jacobin matrix equation is deduced,the speed and the relationship between the terminal position differential,through the analysis of the dynamic modeling method of different advantages and disadvantages,finally using the Lagrange dynamics modeling method,the trajectory of the robot and the mathematical relationship between the joint driving moment,through the establishment of manmachine coupling torque model established after the human-computer interaction torque calculation formula,lay the foundation for the back of the control system design.(4)in the exoskeleton robot control system model is established between the wearer,for lower limb exoskeleton robot control part,first studied the PID control with gravity compensation,the impedance control algorithm,according to the different impedance parameters of the simulation results show that the selection has a great influence on the control effect,selected to draw a set of good control effect of the impedance parameters.For lower limb gait data,MATLAB in the gait data fitting,ADAMS simulation movement of gait curve,this paper introduces a kind of suitable for lower limbs powered exoskeleton robot adaptive learning method,combining with the impedance control,get a kind of variable parameters of the impedance control method,the simulation results show lower limb joints of displacement between actual displacement and the expected error is very small,show that the system with high precision,at last,through experiments on the performance of the control algorithm and the exoskeleton robot assisted effect is verified.