| In recent years,the phenomenon of population aging in China has become increasingly serious,and the incidence of stroke is also on the rise year by year.For stroke patients suffering from ankle dyskinesia,their ankle joints are in the state of foot drop for a long time,and there will be irreversible damage if they cannot receive rehabilitation treatment in time.However,in terms of patients,the limited number of rehabilitation physicians causes them to miss the best treatment opportunity;In terms of rehabilitation physicians,the heavy and monotonous rehabilitation tasks undoubtedly aggravate their work burden greatly.With the advancement of robotics,many researchers have combined it with medical rehabilitation technology,which promotes the rapid development of the field of medical rehabilitation robot.While the single-degree-of-freedom ankle rehabilitation robot is designed as the platform basis in this thesis,combining with the recommendations of the rehabilitation physicians,systematic evaluation and rehabilitation functions are designed and implemented for patients in different conditions and rehabilitation periods.Since the medically used evaluation scale relies entirely on the subjective judgment of the rehabilitation physician,an evaluation function is designed to quantify the condition of the patient’s ankle joint to understand its recovery in real time.For patients in the early stage of stroke whose ankle joints are stiff and have high resistance torque,the designed passive rehabilitation therapy can assist the rehabilitation physician to complete the task of pulling the ankle joint of the patient.For patients in the post-rehabilitation period whose ankle joints’ mobility are significantly increased,the active rehabilitation therapies designed can effectively help them to carry out corresponding muscle strength training.In addition,the game rehabilitation function is designed in order to improve the patient’s enthusiasm for rehabilitation treatment.Because that the patient cannot control the affected ankle joint independently,sEMG is introduced in this thesis to help the patient establish the positive mapping relationship between the subjective movement intention of the affected ankle joint and the actual joint movement angle.Considering the difficulty of maintaining a certain action and the weak sEMG signal for the patient,a new joint angle estimation method is proposed.The antagonistic relationship between the tibialis anterior muscle and gastrocnemius muscle during ankle joint movement is fully used in this method,and the motion type of the ankle joint is correlated with the contraction of a single muscle group.After the recognition of the motion intention and the estimation of the movement angle are completed by using the normalized characteristic value,the continuous and smooth angle estimation curve is obtained,which will be transmitted to the rehabilitation robot as the reference input,and then the rehabilitation robot will assist the patient’s ankle joint to achieve the corresponding movement.As an auxiliary robot,the ankle joint rehabilitation robot is contact with human body directly,and the robot should exhibit some flexibility to ensure human’s safety when the interaction torque between them suddenly increases.Therefore,after the study of the impedance control algorithm,the adaptive control laws of the stiffness parameter and the damping parameter are designed in this thesis,and the moving angle and speed of the robot end are adjusted in real time by using the interactive torque,so that the external flexibility is exhibited,which ensures that the interaction between human and robot can be friendlier. |
