Prototype design of a novel modular two-degree-of-freedom variable stiffness actuator

In bio-inspired robotic applications, multiple-degree-of-freedom actuators are often desired. The current state of the art of variable stiffness actuators consist mostly of different concepts for single-degree-of-freedom joints. An innovative Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator (MACCEPA) concept is presented to specifically accommodate implementation in two-degree-of-freedom joints. A prototype design, based on this concept, is furthermore presented. The working principle and relevant design choices are explained, a zero-dynamic model is derived for future design iterations, and the implementation in a first prototype is discussed.