Force And Trajectory Planning Of The Rigid Flexible Coupled Series-parallel Rehabilitation Mechanical Arm

Under the background of aging population,stroke patients have shown an explosive growth trend.However,most stroke patients are accompanied by some degree of sequelae-hemiplegia after recovery.At present,the traditional one-to-one rehabilitation therapy is often used in the treatment of hemiplegia patients,which is cumbersome and has low therapeutic effect.For the past few years,As the robotics development,both domestic and foreign laboratories and rehabilitation medical institutions have carried out the research of rehabilitation robotic arm.Yet there are still many deficiencies in the driving design and shoulder joint mechanism of the existing rehabilitation robotic arm.Therefore,it is of great significance to design a rigid-flexible coupling series-parallel rehabilitation robotic arm and study its related characteristics.First of all,based on the physiological structure of the human upper limb,the design of 3degrees of freedom of the shoulder joint and 1 degree of freedom of the elbow joint of the rehabilitation robotic arm were determined,and the driving method of the rehabilitation robotic arm was selected.The design of the overall mechanism of the rehabilitation robotic arm is completed according to the adult upper limb size standard.The whole rehabilitation robotic arm is series design in configuration,while the shoulder is designed with parallel nesting mechanism.Then the elbow and wrist parts of the rehabilitation robotic arm are designed separately,both the structural materials and type of driving motor of the robotic arm are selected.The static strength analysis of the designed parts is also done.Secondly,taking the designed rehabilitation mechanical arm as the research object,the forward kinematics equation of the rehabilitation mechanical arm was obtained by using the closure vector method and D-H method respectively for the shoulder and elbow mechanism of the rehabilitation mechanical arm,and then the relationship between the rope length of and the joint angle of the mechanical arm is derived from the geometric relationship of the rehabilitation robotic arm mechanism,followed by the inverse kinematics analysis of the robotic arm using the inverse transformation method and the solution of the working space of the robotic arm.Finally,the simulation analysis is carried out by the given rehabilitation action to obtain the joint angle and robot arm end attitude change curve as well as the rope length and speed change relationship curve with time.Next,the dynamics of the shoulder and elbow parts of the rehabilitation robotic arm are analyzed separately.The planning was then carried out in joint space using a cubic polynomial interpolation method,and the moment variation curves of the shoulder and elbow joints were solved by substituting into the kinetic equations,and then the variation relationship of the rope length,velocity and acceleration is solved by the function equation of the rope length and joint angle.Finally,the relationship between the change of with time for the shoulder joint under the rehabilitation action was solved by using the optimization method.Finally,the trajectory planning analysis and force planning analysis were performed for the rehabilitation robotic arm.Under the given trajectory of rehabilitation action at the end of the rehabilitation mechanical arm,interpolation processing was carried out for the specific trajectory of rehabilitation action at the end of the rehabilitation mechanical arm,and sine function was used to plan the displacement,velocity and acceleration of the end of the rehabilitation mechanical arm.And the relationship between the joint angular velocity and angular acceleration was solved by using the Jacobian matrix.Immediately afterwards,the relationship between motor torque and rope tension is established,and the mechanical arm under the rehabilitation training trajectory is simulated and analyzed.The analysis results show the rationality and feasibility of the designed rehabilitation robotic arm structure,which has certain engineering value.