工程科学学报.第44卷.第3期：420-429.2022年3月 Chinese Journal of Engineering,Vol.44,No.3:420-429,March 2022 https://doi.org/10.13374/j.issn2095-9389.2020.10.23.001;http://cje.ustb.edu.cn 四足机器人软硬地面稳定过渡的腿部主动变刚度调节 策略 刘 帅，赵慧12)，刘清宇2)区 1)武汉科技大学治金装备及其控制教育部重点实验室，武汉4300812)武汉科技大学机械传动与制造工程湖北省重点实验室，武汉 430081 ☒通信作者，E-mail:liuqingyu@wust.edu.cn 摘要针对四足机器人在变刚度地面环境下动态行进时易出现姿态不稳定的问题，本文提出了一种机器人腿部主动变刚度实时 调节策略.该策略根据机器人着地后的机身和腿部的运动状态实时估计出着地腿和地面的耦合刚度.并将前后腿与地面耦合刚度 的差值补偿到相应的着地腿上.该策略能够使机器人着地后迅速适应不同刚度特性的地面，特别是地面刚度相差较大的情况.通 过搭建Simulink-SimMechanics仿真平台，对角腿在同一刚度地面和变刚度地面两种不同的着地环境，对仅利用常规姿态反馈控 制、腿部主动变刚度调节策略与常规姿态反馈控制联合方式进行了对比实验。结果表明，通过腿部主动变刚度调节策略的作用，四 足机器人在软硬地面过渡时实现对机身俯仰角和滚转角的补偿修正，调控效果优于单独通过常规姿态反馈控制. 关键词四足机器人：变刚度地面：软硬地面过渡；主动变刚度；姿态控制 分类号TP242.6 Active and variable stiffness adjustment strategy for legs of quadruped robot for stable transition between soft and hard ground LIU Shuai,ZHAO Hui2),LIU Qing-yu2 1)Key Laboratory of Metallurgical Equipment and Control (Ministry of Education),Wuhan University of Science and Technology,Wuhan 430081,China 2)Key Laboratory of Mechanical Transmission and Manufacturing Engineering(Hubei Province),Wuhan University of Science and Technology,Wuhan 430081,China Corresponding author,E-mail:liuqingyu@wust.edu.cn ABSTRACT Quadruped bionic robots are favored by development experts because of their broad application prospects,such as interstellar exploration,educational companionship,and social inspections.Quadruped robots were developed and inspired by mammals, which are known to exist in most areas on the earth's land surface.However,quadruped robots cannot achieve such an ideal state due to various reasons.At present,the adaptive problem of quadruped robots under a complex and changeable terrain has made significant progress,as reported in related literature.However,the case of robots that are as flexible as mammals in nature and meet the needs of multi-functional and multi-scenarios are still poorly understood.A quadruped robot is prone to posture instability when dynamically traveling in a ground environment with variable rigidity.This work proposes a real-time adjustment strategy of the active variable stiffness of the legs.This strategy estimates the landing in real time based on the motion state of the fuselage and legs after the robot touches the ground.The coupling stiffness of the legs and the ground and the difference between the coupling stiffness of the front and rear legs and the ground is compensated to the corresponding landing legs.This enables the robot to quickly adapt to the ground with different stiffness characteristics after landing,especially when the ground stiffness differs greatly.The Simulink-SimMechanics 收稿日期：2020-10-23 基金项目：国家自然科学基金资助项目(51805381)四足机器人软硬地面稳定过渡的腿部主动变刚度调节 策略 刘    帅1)，赵    慧1,2)，刘清宇1,2) 苣 1) 武汉科技大学冶金装备及其控制教育部重点实验室，武汉 430081    2) 武汉科技大学机械传动与制造工程湖北省重点实验室，武汉 430081 苣通信作者， E-mail: liuqingyu@wust.edu.cn 摘    要    针对四足机器人在变刚度地面环境下动态行进时易出现姿态不稳定的问题，本文提出了一种机器人腿部主动变刚度实时 调节策略，该策略根据机器人着地后的机身和腿部的运动状态实时估计出着地腿和地面的耦合刚度，并将前后腿与地面耦合刚度 的差值补偿到相应的着地腿上. 该策略能够使机器人着地后迅速适应不同刚度特性的地面，特别是地面刚度相差较大的情况. 通 过搭建 Simulink-SimMechanics 仿真平台，对角腿在同一刚度地面和变刚度地面两种不同的着地环境，对仅利用常规姿态反馈控 制、腿部主动变刚度调节策略与常规姿态反馈控制联合方式进行了对比实验. 结果表明，通过腿部主动变刚度调节策略的作用，四 足机器人在软硬地面过渡时实现对机身俯仰角和滚转角的补偿修正，调控效果优于单独通过常规姿态反馈控制. 关键词    四足机器人；变刚度地面；软硬地面过渡；主动变刚度；姿态控制 分类号    TP242.6 Active and variable stiffness adjustment strategy for legs of quadruped robot for stable transition between soft and hard ground LIU Shuai1) ，ZHAO Hui1,2) ，LIU Qing-yu1,2) 苣 1) Key Laboratory of Metallurgical Equipment and Control (Ministry of Education), Wuhan University of Science and Technology, Wuhan 430081, China 2) Key Laboratory of Mechanical Transmission and Manufacturing Engineering (Hubei Province), Wuhan University of Science and Technology, Wuhan 430081, China 苣 Corresponding author, E-mail: liuqingyu@wust.edu.cn ABSTRACT    Quadruped  bionic  robots  are  favored  by  development  experts  because  of  their  broad  application  prospects,  such  as interstellar exploration, educational companionship, and social inspections. Quadruped robots were developed and inspired by mammals, which are known to exist in most areas on the earth's land surface. However, quadruped robots cannot achieve such an ideal state due to various  reasons.  At  present,  the  adaptive  problem  of  quadruped  robots  under  a  complex  and  changeable  terrain  has  made  significant progress, as reported in related literature. However, the case of robots that are as flexible as mammals in nature and meet the needs of multi-functional  and  multi-scenarios  are  still  poorly  understood.  A  quadruped  robot  is  prone  to  posture  instability  when  dynamically traveling  in  a  ground  environment  with  variable  rigidity.  This  work  proposes  a  real-time  adjustment  strategy  of  the  active  variable stiffness of the legs. This strategy estimates the landing in real time based on the motion state of the fuselage and legs after the robot touches the ground. The coupling stiffness of the legs and the ground and the difference between the coupling stiffness of the front and rear legs and the ground is compensated to the corresponding landing legs. This enables the robot to quickly adapt to the ground with different  stiffness  characteristics  after  landing,  especially  when  the  ground  stiffness  differs  greatly.  The  Simulink-SimMechanics 收稿日期: 2020−10−23 基金项目: 国家自然科学基金资助项目（51805381） 工程科学学报，第 44 卷，第 3 期：420−429，2022 年 3 月 Chinese Journal of Engineering, Vol. 44, No. 3: 420−429, March 2022 https://doi.org/10.13374/j.issn2095-9389.2020.10.23.001; http://cje.ustb.edu.cn