Research On Optimizing Force And Compliance Control Of Rigid-flexible Coupled Lower Limb Rehabilitation Robot

In recent years, with the improvement of people's life quality, the service robot is concerned by the society more and more widely. Rehabilitation robot which can help patients with motion dysfunction with the rehabilitation training is developing rapidly.As the wire-driven parallel mechanism is easy to collocate and has a good flexibility,it is easier to meet the requirements of rehabilitation training and is more effective and safer. Therefor it is of great significance to study the rope force and compliance control of the wire-driven lower limb rehabilitation robot.This project is supported by the National Natural Science Foundation of China(51405095), Technological Innovation Talent Special Fund of Harbin (2014RFQXJ037)and the Scientific Research Starting Foundation for Post-doctoral Scientists of Heilong-jiang(LBH-Q15030). The main contents are as follows.Firstly, according to the requirement of gait training, the rigid-flexible coupled robot mechanism is established. According to the drive redundancy of the robot's mechanism, the wire-force optimization model is established with the help of generalized inverse matrix G inverse matrix and Drazin inverse matrix. MTALAB is used to simulate the model and calculate the law of wire-force variation. The performance of the wire-force of different drive redundancy is compared according to the raised wire-force performance index, which supported the setting of the wires.The dynamic model of the robot is established and according to the math model of the wire-driven unit, the influence of the wire's stiffness coefficient K and the wire's damped coefficient B to the frequency characteristic of wire-driven unit is analyzed. The passive compliance of the rigid-flexible coupled lower limb rehabilitation robot is analyzed after that.In consideration of the direct contact of trainer and robot, the impedance control strategy based on force inner ring and position outer ring is established to make sure that the rehabilitation training is effective and safe and the system is flexible. In consideration of the outside disturbance, the feed forward control is used in the impedance control strategy to constitute the compound control strategy of the wire-driven unit. MATLAB/Simulink is used to simulate and analyze the system's control performance and test the effectiveness of the control strategy.Finally, the control system is established using the Leisai motion control card DMC5000,the multifunctional DC servo drive, the Art data acquisition card and the industrial control computer. Wire-driving unit force closed loop experiment, wire-driving unit trajectory tracking experiment and wire-driving unit impedance control experiment are made with the model machine which proves that the established control strategy of the rigid-flexible coupled lower limb rehabilitation robot is effective.