Research On Kinematics Calibration And Compliance Control Of Upper Limb Rehabilitation Robot

As the population of our country enters a moderately aging population,the incidence of stroke is increasing year by year.Rehabilitation and reconstruction of the motion function of stroke patients has also attracted the attention of researchers.Scientific research results show that: timely and systematic rehabilitation training for the limbs of stroke patients has greatly improved the rehabilitation effect of stroke patients.Traditional rehabilitation training relies on one-to-one assistance from a rehabilitation therapist,which has problems such as difficulty in time coordination,low efficiency,poor control accuracy,and high work intensity.With the development of rehabilitation medicine and robotics,rehabilitation robots have been increasingly used in stroke rehabilitation training.In order to improve the control accuracy and ensure the rehabilitation effect,it is necessary to calibrate the motion parameters of the upper limb rehabilitation robot.Considering the fragility of the patient’s affected limb,the flexibility of the mechanism is very important.For rigid mechanisms,the flexibility is mainly achieved by force/position control,which puts forward requirements for the control strategy.In this paper,combined with a three-degree-of-freedom serial-parallel hybrid upper-limb rehabilitation robot prototype,the establishment of the kinematics and dynamics model of the rehabilitation robot is completed,and the correctness of the model is verified by simulation,and the structural parameters of the prototype are calibrated and corrected.A force/position control scheme is proposed for the structural characteristics of the robot and actual training requirements,and a simulation model is built to verify the feasibility of the control scheme.The main research contents of this paper are as follows:For kinematics and dynamics solving problems,this paper uses vector and geometric methods to determine the forward kinematics and inverse kinematics models of the robot.On the basis of kinematics,the Lagrangian method is used to establish the dynamics model of the robot.Then,the Runge-Kutta method and Adams simulation were used to solve the dynamic model under the same parameters,which verified the correctness of the kinematics and dynamic equations.Aiming at the problem of parameter calibration of the rehabilitation robot prototype,this paper uses Qualysis motion acquisition system as the calibration data source,and uses the extended Calman filtering method to process the collected data,establishes an error model,and completes the calibration of the base and the structural parameters on this basis.Aiming at the robot human-computer interaction problem,this paper analyzes the various force/position schemes from the perspective of flexibility,and adopts the admittance principle as the basis of force/position control based on the actual structure of the robot.On this basis,a sliding mode control rule is designed.And fuzzy rules are combined into a fuzzy sliding mode admittance control scheme to realize the tracking of the position while keeping the interaction force within a certain range.Aiming at the verification of force/position control theory,this paper uses Matlab’s Simulink tool to establish a simulation model based on the robot’s dynamics,import the modified mechanism parameters for simulation experiments,and analyze the simulation results.The control scheme is evaluated based on the simulation results.This research lays the foundation for the subsequent development of serial-parallel hybrid upper limb rehabilitation robots.The robot structure parameter method and robot force/position control scheme used have certain applicability,and can be used for the calibration and force/position of other robots.Control research provides reference.