Double-Arm Upper Limb Rehabilitation Robot Research On Mechanism Design And Self-Collision Avoidance Trajectory Planning

By 2020,the number of stroke patients in China exceeds 17 million,and more than70% of the patients are unable to care for themselves because of the sequelae of various degrees of limb movement disorders.Compared to lower limbs,the upper limbs of the human body are responsible for more complex and important tasks in daily life,Therefore,the development of upper limb rehabilitation robots that can assist rehabilitation physicians in the rehabilitation of patients has gradually become a hot research topic today.In this paper,a 12-degree-of-freedom dual-arm upper limb rehabilitation robot is designed,mainly in terms of mechanism design,kinematics and self-collision avoidance trajectory planning.Firstly,according to the physiological structure and movement mechanism of human upper limbs,combined with the clinical design requirements of rehabilitation robots,the modular design of the two-arm upper limb rehabilitation robot,which can rehabilitate the three joints of the shoulder,elbow and wrist of both arms of patients.Multiple limits are provided in the mechanism and the length of the robot arm can be adjusted according to the actual arm length of the patient to improve the safety of robot movement and human-robot compatibility.Secondly,the kinematic models of the left and right robotic arms were established by using the D-H method,and the forward and inverse kinematic analysis and the solution of Jacobi matrix were carried out.The working space of the two arms was solved by using the Monte Carlo method.On the basis of this work,the dexterity of the robotic arm in the working space was analyzed,and it was proved that the robotic arm has high dexterity and good motion performance.Furthermore,the spatial envelope box technique is used to simplify the double-arm model,and the collision detection is carried out by calculating the minimum distance between the models.The improved artificial potential field method is used to plan the self-avoidance path of the double-arm motion,and its simulation is verified,and the spatial trajectory planning of the double-arm is carried out by using the fifth polynomial interpolation method to meet the requirements of smooth displacement and continuous velocity and acceleration.Finally,the experimental prototype platform of the double-armed upper limb rehabilitation robot was built,the working range of the left and right mechanical arms was measured,and the collision detection experiment was conducted for the double-armed self-avoidance motion,and the minimum distance between the double-arms was calculated by using the actual angle change of the motors,and the results showed that the minimum distance was always greater than the absolute safety distance indicating that the double-arms did not collide during the motion,and the high accuracy of the trajectory tracking of the rehabilitation robot was proved by the double-armed motion trajectory tracking experiment.