A generalized framework to achieve coordinated admittance control for multi-joint lower limb robotic exoskeleton

• Published in: IEEE International Conference on Rehabilitation Robotics Vol. 2017; pp. 228 - 233
• Main Authors: Gui, Kai, Liu, Honghai, Zhang, Dingguo
• Format: Conference Proceeding Journal Article
• Language: English
• Published: United States IEEE 01.07.2017
• Subjects: Admittance; Biomechanical Phenomena; central pattern generator; coordinated admittance control; Electromyography; Electromyography - instrumentation; Equipment Design; Exoskeleton Device; Exoskeletons; Humans; joint space; Knee Joint - physiology; Lower Extremity - physiopathology; Muscle, Skeletal - physiopathology; Neurological Rehabilitation - instrumentation; Neurological Rehabilitation - methods; Robot kinematics; robotic exoskeleton; Torque; Trajectory
• ISSN: 1945-7901; 1945-7901
• DOI: 10.1109/ICORR.2017.8009251

Traditional joint space admittance controller for N-DOF robotic systems is complexity and easily leads to incongruous movement among all joints. Our study introduces a central pattern generator (CPG) network into one-dimension joint space admittance control for the custom-made lower limb robotic exoskeleton with four DOFs, to guarantee the coordinated movement and security of users. The predefined trajectories for four joints are produced by CPG. Unilateral knee joint torque of subjects is detected based on corresponding muscle EMG signals. The torque is transformed into an additional set of state variables for CPG based on the one-dimension admittance controller. CPG harmonically adjusts the predefined trajectories by the additional state variables. Finally, the robotic exoskeleton completes the predefined trajectories with a classical PID controller.