An Adaptive and Hybrid End-Point/Joint Impedance Controller for Lower Limb Exoskeletons

This paper explores how to best control lower limb exoskeletons to help patients walk better. It looks at two common ways to control these robots: by focusing on the joints of the leg or by focusing on the end-point (the foot). The paper then proposes a new control method that combines the strengths of both approaches. This hybrid controller adapts the stiffness of the robot at the foot to provide support where it's needed, while also ensuring the joints move correctly. The controller was tested on a Lokomat®Pro V5, a two-link rehabilitation robot, with both healthy individuals and a person with a spinal cord injury. The results suggest this hybrid controller is a promising approach for lower limb exoskeletons.

• 1
  The hybrid controller is a feasible approach for exoskeleton devices, combining the benefits of end-point control in shaping desired stiffness and joint control to promote correct angular changes.
• 2
  The adaptation algorithm effectively adjusts end-point stiffness based on the subject's performance in different gait phases, increasing stiffness where kinematic errors are larger.
• 3
  The proposed approach can potentially be generalized to other robotic applications for rehabilitation or assistive purposes.