Research progress in the design and application of robot variable stiffness actuators

XU Yapeng; ZHANG Zhou; WANG Caidong; WANG Liangwen; WANG Shoufang

doi:10.16578/j.issn.1004.2539.2026.02.001

Abstract：[Significance]There is an urgent demand for applications such as human-robot interaction and special operations,which imposes higher requirements on the compliance and dynamic adaptability of robot joints.As the core technology for compliant robot joints,variable stiffness actuators(VSAs)have become a research hotspot.To systematically sort out the design,control,application and development trends of VSAs and grasp their core research threads,a comprehensive review of relevant research achievements was conducted.[Analysis]Firstly,literatures at home and abroad in the past decade were collected and analyzed,and the research popularity and depth of VSAs were statistically analyzed,revealing the current macro history of VSAs.Secondly,the stiffness adjustment principle,transmission mechanism design,and control strategy of VSAs were classified,and the advantages and limitations of various variable stiffness theories and methods were discussed based on theoretical models.The characteristics of their adjustment speed,bandwidth,energy consumption,as well as the load capacity and response bandwidth of the actuator,were analyzed in different schemes.Thirdly,combined with specific cases,the applications of VSAs in fields such as humanoid robots,exoskeleton robots,industrial robot terminals,and special robots were explored.Finally,the development trend and technical challenges of VSAs in the field of robotics were discussed,and potential technological breakthroughs and applications were explored.With the continuous deepening of research,VSAs are expected to assist robots in achieving super-efficient,intelligent,and collaborative by interdisciplinary integration.