Research On Mechanism Design And Control Of 6-dof Upper Limb Rehabilitation Robot

At present,there are about 7 million stroke patients in China,and the proportion of patients with permanent disabilities is as high as 75%.Stroke sequelae lead to the loss of part of the limb behavior ability and reduce the quality of life of patients.Among them,the upper limbs undertake more heavy activities than the lower limbs,so the rehabilitation training of the upper limb is more complex than the lower limb.Aiming at the rehabilitation of upper limb sequelae of stroke patients in China,this paper develops an upper limb rehabilitation robot,which mainly studies the mechanism design,kinematics and manipulator control.First of all,according to the rehabilitation needs of most patients and the analysis of movement mechanism,a six degree of freedom upper limb rehabilitation robot was designed based on the requirements of safety,comfort,and use value.The upper limb rehabilitation robot can complete the rehabilitation training of shoulder,elbow,forearm and wrist joints,adjust the arm length for patients with different body types.During the training process,the parts between the patient’s arm and the mechanical arm do not interfere,which can improve the comfort and safety of the patient’s training.Secondly,according to the designed structure,the D-H method is used to analyze the kinematics of the manipulator,and the quintic polynomial and cubic spline interpolation method are used to complete the trajectory planning of the sagittal plane linear motion,circular motion and spatial linear motion in the joint space of the manipulator,which meets the requirements of smooth displacement,continuous velocity and acceleration.Furthermore,the simulation model of manipulator is built based on Simulink module,and the trajectory tracking verification is carried out.Because the manipulator model is not a linear time-invariant system and is susceptible to external interference,in order to increase the stability of the system and reduce the external uncertaint ies,the fuzzy control strategy is applied to PID control,and a fuzzy PID controller is designed.Through the control of the motor,the response speed of the manipulator is improved.Finally,the electrical system of the upper limb rehabilitation robot is built,and the motion range of each joint is measured;the calibration experiment of the manipulator sensor is carried out,and the working accuracy in normal operation is detected;the trajectory tracking experiment under no-load condition is carried out.Comparing and analyzing the experimental results,it is proved that the rehabilitation robot has high trajectory tracking accuracy and good running performance.