Research On Control System And Control Strategy Of Lower Limbs Rehabilitation Robot

With the growth degree of aging and frequent natural disasters, there are a large number of patients with lower limbs motor dysfunction in China, which results a pressing need for rehabilitation robot. Under such a background, this paper researches control system, the trajectory planning of changeable workspace, control strategies and the experiments all four aspects referring to the lower limbs rehabilitation robot designed by our group.Firstly, in order to enhance the security degree of the lower limbs rehabilitation robot, the dual safe limit including electric and software is designed. Considering the practical needs, this paper constructs a robust system of hardware, designs an integrated software system including various modes of rehabilitation training, patient information management and user information management. After the rectification and reform of the lower limbs rehabilitation robot, the EMC test is passed.Secondly, the lengths of both thigh and crus of the patient and range of motion are regarded as variables, and the changeable workspace is solved. This paper designs both circular path and line path. To meet the special demands of several patients for training trajectory, graphics teaching mode in which users can draw circular path, line path and any path is worked out. Polynomial interpolation is used to handle the displacement, velocity and acceleration to make training trajectory steadier.Moreover, active training, assisted training and active training are designed. Impedance control strategy is applied to passive training to improve the flexibility of lower limbs rehabilitation robot. When the force of patient suddenly changes, the patient is protected. In assisted training, an auxiliary force is designed to support the patients with different auxiliary force based on the impedance model. When active training is performed, lower limbs rehabilitation robot simulates sandy environment based on the sandy model, making the patients feel the different stiffness sandy environment. This paper also completes the computer simulation of all three training modes and analyzes the influence of corresponding parameters.Finally, experiments of lower limbs rehabilitation robot are performed. Torque transducer filtering, gravity parameter calculation and leg length calculation are performed in basic experiment part. Active training, assisted training and active training experiments are completed in control system experiments part, and the corresponding control strategies are verified also.