A method to determine the topology of custom torsional elastic element for the lightweight rotary series elastic actuator

Abstract

Abstract Compact and lightweight rotary series elastic actuator (SEA) is a new scheme to realize safe and friendly human-robot interaction of exoskeletons and other human-robot interaction applications. The custom monolithic torsional elastic element is a good choice for the compact design of rotary SEA, but there is a lack of guidance on selecting the topology of elastic elements in a lightweight SEA design. In this paper, with the help of the concept of specific energy, a method based on finite element simulation environment and parametric 3D CAD environment is proposed to determine the topology of the elastic element suitable for lightweight SEA by maximizing the specific energy. By adopting this method, we come to this conclusion: The topology, Archimedes-spiral-based double spiral structure without the outer ring, can be determined as a suitable topology of elastic element for a lightweight rotary SEA.