Chen Zhihua, Wang Shoukun, Wang Junzheng, Xu Kang, Lei Tao, Zhang Hao, Wang Xiuwen, Liu Daohe, Si Jinge
Key Laboratory of Intelligent Control and Decision of Complex Systems, School of Automation, Beijing Institute of Technology, Beijing 100081, China; Key Laboratory of Servo Motion System Drive and Control, Ministry of Industry and Information Technology, School of Automation, Beijing Institute of Technology, Beijing 100081, China.
Key Laboratory of Intelligent Control and Decision of Complex Systems, School of Automation, Beijing Institute of Technology, Beijing 100081, China; Key Laboratory of Servo Motion System Drive and Control, Ministry of Industry and Information Technology, School of Automation, Beijing Institute of Technology, Beijing 100081, China.
ISA Trans. 2021 Feb;108:367-380. doi: 10.1016/j.isatra.2020.08.033. Epub 2020 Sep 14.
This paper provides a legged stable walking control strategy based on multi-sensor information feedback about BIT-NAZA-II, a large load parallel hexapod wheel-legged robot developing for the problem of vertical contact impact and horizontal sliding of heavy leg robot in complex terrain environments. The BIT-NAZA-II robot has six legs and six wheels, and the wheels are installed on the foot-end. The wheels of each foot-end for the legs of the robot are locked when walking with legs. In order to realize the smooth transition between swing phase and stance phase, the leg motion is divided into different stages for control by state machine switching controller based on event (SMSCE). In the Z-direction, in order to avoid the shaking of the body caused by the contact impact at the moment of contact between the foot-end and the ground during the walking of the robot, an active compliance controller (ACC) based on impedance control (IC) is applied to solve the problem of contact impact. Moreover, in the X-direction, the swing leg retraction (SLR) based on Bezier curve (BC) is introduced to generate the foot-end trajectory of the robot, which solves the slip problem of the heavy leg robot and improves the horizontal stability. Finally, the control strategy of stable walking is respectively verified by the simulations and experiments. The results show that the ACC based on IC can effectively reduce the contact impact between the foot-end and the ground in the Z-direction and improve the stability of body. Besides, the anti-sliding ability is realized after introducing SLR based on BC in the X-direction, and we also verify that stable walking control strategy is effective, which provides a reference value for the stable walking of heavy leg robot in complex terrain.
本文针对大型负载并联六足轮腿机器人BIT-NAZA-II，提出了一种基于多传感器信息反馈的腿部稳定行走控制策略，该机器人是为解决重型腿式机器人在复杂地形环境中的垂直接触冲击和水平滑动问题而研制的。BIT-NAZA-II机器人有六条腿和六个轮子，轮子安装在脚端。机器人腿部每个脚端的轮子在腿部行走时锁定。为了实现摆动阶段和支撑阶段之间的平稳过渡，基于事件的状态机切换控制器（SMSCE）将腿部运动划分为不同阶段进行控制。在Z方向上，为了避免机器人行走时脚端与地面接触瞬间的接触冲击引起的车身晃动，应用了基于阻抗控制（IC）的主动柔顺控制器（ACC）来解决接触冲击问题。此外，在X方向上，引入基于贝塞尔曲线（BC）的摆动腿回缩（SLR）来生成机器人的脚端轨迹，解决了重型腿式机器人的滑动问题，提高了水平稳定性。最后，通过仿真和实验分别验证了稳定行走控制策略。结果表明，基于IC的ACC能够有效降低脚端与地面在Z方向上的接触冲击，提高车身稳定性。此外，在X方向上引入基于BC的SLR后实现了防滑能力，同时也验证了稳定行走控制策略的有效性，为重型腿式机器人在复杂地形下的稳定行走提供了参考价值。
