Abstract:In order to improve the anthropomorphosis level and flexibility of the upper limb exoskeleton robot, a compliant 4-DOF (degree of freedom) upper limb exoskeleton robot driven by serial elastic actuator (SEA) and Bowden cable is designed. Firstly, A six-link double parallelogram mechanism is designed to establish a virtual rotational center and realize 3-DOF motion of human shoulder. Then, a drive module based on the SEA and Bowden cable is designed to separate the actuator and the robot joint, reduce the complexity of the structure, relieve the mass of joints and get the feedback of the torque and position information. Finally, the kinematics and dynamics model of the robot is built for developing an impedance controller. The impedance control test is carried out on the elbow joint. The results show that the root mean squared error of the torque tracking is 0.33 N·m when the virtual stiffness coefficient is in the range of 0.5 N·m/(°)~1.5 N·m/(°), the root mean squared error of the torque tracking is 0.57 N·m when the virtual damping coefficient is in the range of 0.001 N·m·s/(°)~0.01 N·m·s/(°). The result shows that the stiffness and damping of the elbow joint can be changed by adjusting the impedance coefficient of the impedance controller, which promotes the compliance of the human-robot interaction. So the robot can meet the needs of rehabilitation training.
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