Novel Compliant Actuator for Safe and Ergonomic Rehabilitation Robots - Design of a Powered Elbow Orthosis

Rehabilitation robotics is a young discipline that will become an imperative when the age of the population will keep rising. A short overview of the necessary general requirements of rehabilitation robotics will be given. Subsequently, this paper introduces a novel rotational actuator with adaptable compliance that has several characteristics that make it very suitable for use within this subfield of robotics. The MACCEPA concept and design are described in detail. The actuator can be comprised as a fully adaptable torsion spring with an online variable spring constant. It is shown, depending on the design parameters, that the torque is a quasi linear function with respect to the angle between equilibrium position and actual position. The change of the pre-tension also has a quasi linear effect on the torque. Another advantage is that the actuator can be built with standard components, e.g. electrical servo motors. The implementation of this novel actuator in rehabilitation robotics will be discussed by means of a case-study, the concept of a smart, wearable elbow rehabilitation device.