Abstract 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.

中文翻译：

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复杂未知地形下轮腿机器人变目标刚度自适应阻抗控制

摘要 轮腿机器人在地面上作业时会与复杂的未知地形进行实时交互，如果不进行调节，可能会导致全身倾斜和不稳定。希望通过在许多领域中广泛使用的阻抗控制（IC）来随着地形几何形状的变化保持整个身体的水平姿势。但是，由于事先不知道地形相对于机器人的刚度和位置，因此在使用 IC 时会出现力跟踪误差，这是导致机器人倾斜的主要原因。在本文中，提出了一种自适应可变阻抗控制（AVIC）方法，以最小化施加在身体上的每条腿的力的力跟踪误差，从而保持整个身体的水平姿势并提高稳定性。这种控制方法通过调整目标刚度来补偿地形的不确定性。就动态力跟踪误差的存在而言，所提出的控制方法还允许机器人适应变化以跟踪所需的力。通过稳定的力跟踪应用证明了中航工业稳定性的理论分析。将数值和实验结果与使用 IC 获得的结果进行比较，并在复杂的未知地形上验证了所提出的控制方法。通过稳定的力跟踪应用证明了中航工业稳定性的理论分析。将数值和实验结果与使用 IC 获得的结果进行比较，并在复杂的未知地形上验证了所提出的控制方法。通过稳定的力跟踪应用证明了中航工业稳定性的理论分析。将数值和实验结果与使用 IC 获得的结果进行比较，并在复杂的未知地形上验证了所提出的控制方法。