Adaptive impedance control with variable target stiffness for wheel-legged robot on complex unknown terrain
Adaptive impedance control with variable target stiffness for wheel-legged robot on complex unknown terrain
复制标题
复杂未知地形轮腿机器人可变目标刚度自适应阻抗控制
DOI：
10.1016/j.mechatronics.2020.102388
复制
发表时间：
2020-08-01
期刊：
影响因子：
3.3
通讯作者：
Shi, Mingxin
中科院分区：
文献类型：
--
作者：
Xu, Kang;Wang, Shoukun;Shi, Mingxin
轮腿式机器人在地面上运行时会与复杂的未知地形进行实时交互，如果不进行调节，可能会导致整个身体倾斜和不稳定。期望通过在许多领域中广泛使用的阻抗控制（IC）来实现随着地形几何形状的变化而保持整个身体的水平姿态。然而，由于刚度和位置的地形相对于机器人是事先不知道的，力跟踪误差发生时，使用IC，这是机器人倾斜的主要原因。本文提出了一种自适应变阻抗控制（AVIC）方法，以最小化各腿施加在身体上的力的力跟踪误差，从而保持整个身体的水平姿态，提高稳定性。该控制方法通过调整目标刚度来补偿地形不确定性。在动态力跟踪误差存在的情况下，所提出的控制方法也允许机器人自适应地跟踪期望力的变化。通过一个稳定的力跟踪应用，证明了中航工业的稳定性的理论分析。将仿真和实验结果与IC仿真结果进行了比较，并在复杂未知地形上验证了所提出的控制方法的有效性。
Wheel-legged robots operating on the ground experience real-time interactions with the complex unknown terrain, which may lead to tilting of the whole body and instability if no regulated effort is made. Maintaining a horizontal posture of the whole body with changes in the terrain geometry via impedance control (IC) that is widely used in many fields is desirable to be realized. However, because the stiffness and location of the terrain relative to the robot are not known in advance, the force-tracking error occur when using IC, which is the main cause of robot tilting. In this paper, an adaptive variable impedance control (AVIC) method is proposed to minimize the force-tracking error for the forces of each leg that are exerted on the body, thereby maintaining a horizontal posture of the whole body and improving the stability. This control method is applied by adjusting the target stiffness to compensate for terrain uncertainties. In terms of the existence of the dynamic force tracking error, the proposed control method also allows the robot to adapt to changes to track the desired force. The theoretical analysis of the stability of the AVIC was demonstrated through a stable force-tracking application. The numerical and experimental results were compared to those obtained using IC, and the proposed control method was validated on complex, unknown terrain.