Journal of Bionic Engineering ›› 2022, Vol. 19 ›› Issue (5): 1392-1404.doi: 10.1007/s42235-022-00205-0

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Design and Analysis of a 2-DOF Actuator with Variable Stiffness Based on Leaf Springs

ShangKui Yang1,2,3, Peng Chen1,2,4, DongQi Wang1,2, Yi Yu1,2,4, YuWang Liu1,2   

  1. 1 State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110000, China  2 Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110000, China  3 Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education School of Mechanical Engineering, Tianjin University, Tianjin 300192, China  4 University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2022-01-04 修回日期:2022-04-09 接受日期:2022-05-11 出版日期:2022-09-10 发布日期:2022-09-24
  • 通讯作者: YuWang Liu E-mail:liuyuwang@sia.cn
  • 作者简介:ShangKui Yang1,2,3, Peng Chen1,2,4, DongQi Wang1,2, Yi Yu1,2,4, YuWang Liu1,2

Design and Analysis of a 2-DOF Actuator with Variable Stiffness Based on Leaf Springs

ShangKui Yang1,2,3, Peng Chen1,2,4, DongQi Wang1,2, Yi Yu1,2,4, YuWang Liu1,2   

  1. 1 State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110000, China  2 Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110000, China  3 Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education School of Mechanical Engineering, Tianjin University, Tianjin 300192, China  4 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-01-04 Revised:2022-04-09 Accepted:2022-05-11 Online:2022-09-10 Published:2022-09-24
  • Contact: YuWang Liu E-mail:liuyuwang@sia.cn
  • About author:ShangKui Yang1,2,3, Peng Chen1,2,4, DongQi Wang1,2, Yi Yu1,2,4, YuWang Liu1,2

摘要: Variable Stiffness Actuator (VSA) is the core mechanism to achieve physical human–robot interaction, which is an inevitable development trend in robotic. The existing variable stiffness actuators are basically single degree-of-freedom (DOF) rotating joints, which are achieving multi-DOF motion by cascades and resulting in complex robot body structures. In this paper, an integrated 2-DOF actuator with variable stiffness is proposed, which could be used for bionic wrist joints or shoulder joints. The 2-DOF motion is coupling in one universal joint, which is different from the way of single DOF actuators cascade. Based on the 2-DOF orthogonal motion generated by the spherical wrist parallel mechanism, the stiffness could be adjusted by varying the effective length of the springs, which is uniformly distributed in the variable stiffness unit. The variable stiffness principle, the model design, and theoretical analysis of the VSA are discussed in this work. The independence of adjusting the equilibrium position and stiffness of the actuator is validated by experiments. The results show that the measured actuator characteristics are sufficiently matched the theoretical values. In the future, VSA could be used in biped robot or robotic arm, ensuring the safety of human–robot interaction.

关键词: Physical human–robot interaction , · 2-DOF , · Bionic wrist joints , · Variable stiffness actuator , · Leaf spring

Abstract: Variable Stiffness Actuator (VSA) is the core mechanism to achieve physical human–robot interaction, which is an inevitable development trend in robotic. The existing variable stiffness actuators are basically single degree-of-freedom (DOF) rotating joints, which are achieving multi-DOF motion by cascades and resulting in complex robot body structures. In this paper, an integrated 2-DOF actuator with variable stiffness is proposed, which could be used for bionic wrist joints or shoulder joints. The 2-DOF motion is coupling in one universal joint, which is different from the way of single DOF actuators cascade. Based on the 2-DOF orthogonal motion generated by the spherical wrist parallel mechanism, the stiffness could be adjusted by varying the effective length of the springs, which is uniformly distributed in the variable stiffness unit. The variable stiffness principle, the model design, and theoretical analysis of the VSA are discussed in this work. The independence of adjusting the equilibrium position and stiffness of the actuator is validated by experiments. The results show that the measured actuator characteristics are sufficiently matched the theoretical values. In the future, VSA could be used in biped robot or robotic arm, ensuring the safety of human–robot interaction.

Key words: Physical human–robot interaction , · 2-DOF , · Bionic wrist joints , · Variable stiffness actuator , · Leaf spring