Design and Hierarchical Force-Position Control of Redundant Pneumatic Muscles-Cable-Driven Ankle Rehabilitation Robot

Ankle dysfunction is common in the public following injuries, especially for stroke patients. Most of current robotic ankle rehabilitation devices are driven by rigid actuators and have problems such as limited degrees freedom, lack safety compliance, poor flexibility. In this letter, we design a new type compliant robot redundantly pneumatic muscles (PMs) cables to provide full range motion torque ability human with enhanced adaptability, attributing PM's high power/mass ratio, good flexibility lightweight advantages. The joint can be compliantly three freedom perform dorsiflexion/plantarflexion, inversion/ eversion, adduction/abduction training. order keep all PMs tension which essential ensure robot's controllability patient's safety, Karush-Kuhn-Tucker (KKT) theorem analytic-iterative algorithm utilized realize hierarchical force-position control (HFPC) scheme optimal force distribution redundant robot. Experiment results demonstrate that kept during while position tracking accuracy acceptable, ensures stability throughout robot-assisted