| Rehabilitation training can effectively treat sequelae such as hemiplegia caused by stroke.A universal method of rehabilitation treatment is to help patients do limb training through doctors,which is not only inefficient,but also consumes manpower and financial resources.Although the existing exoskeleton upper limb rehabilitation robot can replace doctors for rehabilitation training,it is expensive and only suitable for large rehabilitation hospitals.To address these problems,a plan of upper limb rehabilitation robot is proposed in this paper,which has the advantages of light weight,high cost performance and safe operation,and is suitable for family or small and medium rehabilitation institutions.Control the robot's movement trajectory by controlling the posture variables of the robot mobile platform,so as to drive the patient's upper limbs to complete the flexion and stretch training of the shoulders and elbows.Moreover,the flexibility of passive and active training can be realized according to the contact force between the affected limb and the end of the robot,and the training effect of hemiplegic patients can be improved.The main research contents are as follows:(1)Overall plan of the upper limb rehabilitation robot is proposed according to the clinical rehabilitation mechanism and upper limb movement mechanism of hemiplegia after stroke.And its mechanical structure,hardware system and software platform are analyzed and designed.(2)Kinematic model and trajectory tracking error equation of the robot mobile platform are established in the basis of Mecanum-wheel's structural characteristics.Two trajectory tracking controllers on PID control and backstepping sliding mode algorithm is designed respectively based on kinematic model.Through the analysis of MATLAB simulation results of the two controllers under different trajectories and the addition of disturbances,it is obtained that the robot trajectory tracking controller based on the backstepping sliding mode algorithm has better tracking effect and stronger robustness.It can meet the requirements of rehabilitation medicine and subject indicators.(3)Based on admittance control theory,contact force control research is conducted on robot passive training and active training.On the basis of the existing trajectory tracking controller,an admittance control outer loop is added to convert the contact force between man and machine into a position correction amount.By tracking the corrected desired trajectory,the compliant control of the contact force is achieved.The reliability of the algorithm is verified by MATLAB simulation,and the influence on the system response is analyzed by changing the admittance parameters,which provides a reliable basis for the parameter selection in engineering implementation.(4)Develop a prototype of the upper limb rehabilitation robot,and carry out trajectory tracking control experiment and contact force control experiment.It not only completes the mechanical structure design of the prototype,embedded software and host computer system software design,but also designs an embedded system hardware circuit,and proposes a fusion positioning method of optical mouse and ultrasonic sensors.The experimental results show that the robot's position error can be controlled within ±3mm,and the direction angle error is within ±0.04 rad.Meanwhile selecting appropriate admittance parameters can adjust the intensity of rehabilitation training,improve the flexibility of the system,and ensure the safety and reliability of training. |
