Variable Stiffness Actuators: A Review of the Structural Research

Abstract

Variable stiffness actuators (VSA) are developed to meet the strict requirements of the next generation of robots with physical human-robot interaction or high dynamic motions. These requirements pose new challenges to the design of actuators to make them safe, energy-efficient, and highly dynamic. A classification of the different VSAs based on the principles of stiffness adjustments is proposed. Then the stiffness properties, load capacities, deformability and energy capacities of each kind of VSAs are analyzed respectively and then compared and concluded. This conclusion allows for designers of new devices to choose and design VSAs according to their targeted application. The existing problems and future trends of VSAs are also discussed.