Research On Dynamic Model And Control Of Lower Limb Soft Exosuit

Astronauts will not be too far away to land on extraterrestrial planets such as the moon.The complex environment on the surface of extraterrestrial planets will make it difficult for astronauts to move on extraterrestrial planets.Therefore,it is necessary to establish a dynamic model of the human body according to the walking characteristics of the human body,design a set of soft exosuit for lower limbs,and then research related control strategies on this basis.This article will study the dynamic modeling and control strategy of the lower extremity soft exosuit.First of all,this article refers to the physiological structure of the human body and the characteristics of the lower extremity joint activities,and determines the size parameters and motion range of the lower extremities according to the characteristics of the lower extremity walking gait,and obtains the degree of freedom of movement of each joint.Conceptual design of the lower limb soft exosuit,including its mechanical structure,perception system,drive system and control system.Secondly,this paper establishes a model of the joint coordinate system of the lower limbs of the human body,analyzes the forward and inverse kinematics of the soft exosuit of the lower limbs,and obtains the inverse kinematics equation of the lower limb joint angle.Analyze the joint hysteresis resistance torque generated at the joints of the spacesuit under the pressure state,and obtain the hysteresis resistance torque variation curve through experiments.According to the Lagrangian equation,the dynamic equation of the lower limb walking assist suit is established,and the torque change curve at the motor under a single gait cycle of the lower limb is calculated.Third,according to the results of the analysis,select the motor,reducer,battery,torque transmission equipment and other components.Based on the conceptual design of the lower limb soft exosuit,the overall structure of the lower limb soft exosuit was designed in detail.The overall structure of the backpack,the structure of the drive unit and the structure of the flexible straps at the joints are designed,and the specific parameters of each part are obtained.Create a 3D model of the lower limb soft exosuit in Creo and import it into the ADAMS system.Add the connection relationship of each part in ADAMS,import the gait curve as the lower extremity motion curve into ADAMS as the driving characteristic of the lower extremity,use the cable module in ADAMS,design the structure of the Bowden wire in the model,and perform simulation to get the motor position The torque change curve to verify the accuracy of the dynamic model.Finally,the iterative learning algorithm is used to control,the controllers of various iterative learning algorithms are designed,and the convergence of these algorithms is analyzed.Use MATLAB to simulate the dynamic model with adaptive iterative learning algorithm,PD-iterative learning algorithm and variable gain iterative learning algorithm,compare the simulation results,and find out the iterative learning control strategy with the highest control accuracy.