Design, Realization and Verification of a Novel Knee Joint Actuator for Robotic Exoskeletons

In this paper, a novel electromechanical knee joint actuator is developed and applied to a lower limb exoskeleton. In the first part, performance requirements for knee joint actuators used in robotic exoskeletons are gathered by literature research and biomechanical analysis. Based on the obtained performance requirements, two knee joint actuator concepts are developed and compared in simulation, with the scope to analyse the dynamic behaviour and efficiency. Based on the results of the simulation, a novel electromechanical actuator using a wire gear and an internal rotor motor is designed. The novel actuator is applied to a knee joint exoskeleton prototype. The verification results show the feasibility and efficiency of the developed actuator, with an efficiency of the mechanical transmission of at least 76 %.