张霞, 胡晋嘉, 罗天洪, 陈仁祥, 桥本稔. 穿戴式步行辅助机器人的混合控制方法及其稳定性[J]. 机器人, 2017, 39(4): 489-497. DOI: 10.13973/j.cnki.robot.2017.0489
引用本文: 张霞, 胡晋嘉, 罗天洪, 陈仁祥, 桥本稔. 穿戴式步行辅助机器人的混合控制方法及其稳定性[J]. 机器人, 2017, 39(4): 489-497. DOI: 10.13973/j.cnki.robot.2017.0489
ZHANG Xia, HU Jinjia, LUO Tianhong, CHEN Renxiang, HASHIMOTO Minoru. A Hybrid Control Method for a Wearable Walking-Assist Robot and Its Stability[J]. ROBOT, 2017, 39(4): 489-497. DOI: 10.13973/j.cnki.robot.2017.0489
Citation: ZHANG Xia, HU Jinjia, LUO Tianhong, CHEN Renxiang, HASHIMOTO Minoru. A Hybrid Control Method for a Wearable Walking-Assist Robot and Its Stability[J]. ROBOT, 2017, 39(4): 489-497. DOI: 10.13973/j.cnki.robot.2017.0489

穿戴式步行辅助机器人的混合控制方法及其稳定性

A Hybrid Control Method for a Wearable Walking-Assist Robot and Its Stability

  • 摘要: 引入生物控制理论来改善步行辅助中的人机交互柔顺性和多关节协调自律控制,探索一种髋关节CPG(中枢模式发生器)控制、膝关节分级阻抗控制和髋/膝关节联动控制3部分相结合的新型混合控制方法.首先,利用CPG自激振荡行为和对外交流的特性获得理想的主/从髋关节目标轨迹,并建立CPG对称抑制网络来维持左、右髋关节逆相位,以便实现复杂人机环境中的步行稳定性.其次,根据步态要求,设计高阻抗和低阻抗分级控制规律,分别获得支撑期和游脚期的膝关节力矩.最后,通过建立髋/膝关节关联函数,建立髋关节CPG控制与膝关节阻抗控制的链接,实现步行中自然的髋/膝关节联动控制.利用李亚普诺夫稳定性理论研究了混合控制方法的稳定性,计算机仿真分析和步行实验证明了混合控制方法可有效地生成步行中自然的髋/膝关节运动.

     

    Abstract: Biologically-inspired control theory is introduced to improve human-robot interaction flexibility and multi-joint coordinated autonomous control in walking assist, and a new hybrid control method is explored. The hybrid control method consists of CPG (central pattern generator) based hip joint control, knee joint hierarchical impedance control and a hip-knee joint linkage control. Firstly, CPG self-excited oscillation and its external communication characteristics are utilized to obtain the desired active/passive trajectories of the hip joints. In addition, a symmetrical inhibitory network of CPGs is built to maintain anti-phase of the left and right hip joints, and thus to realize stable walking in the complicated HRI (human-robot interaction) environment. Secondly, a high and low impedance hierarchical control law is designed according to gait requirements to obtain the knee joint torque in stance and swing phases respectively. Finally, a linkage mechanism of hip-knee joints is implemented to connect the hip joints CPG control to the knee joints impedance control, and thus to establish natural movement of hip and knee joints in walking. The stability of the hybrid control method is analyzed using Lyapunov stability theory. Computer simulation analysis and walking experiments are carried out to demonstrate that the proposed control framework is effective in generating natural hip and knee joint movement in walking.

     

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