Development and control of a Bowden-cable actuated exoskeleton for upper-limb rehabilitation

This paper deals with the development and control of an upper limb exoskeleton used for the robotic rehabilitation of stroke patients. Bowden-cable actuators with a high power-weight ratio are applied in the robot system to provide remote power transmission and simplify the mechanical design. The kinematics model of the exoskeleton is analyzed and optimized to eliminate singularities from the desired workplace and achieve natural human-robot interaction. A real-time control system is established in xPC target environment and used to process the feedback signals from the force sensor and potentiometers and execute the control algorithm. An impedance control scheme is developed to provide interactive therapy training to the patients with different disability levels. Preliminary experiments have been carried out in two different training modes to evaluate the performance of the proposed exoskeleton and control approach.