动态环境下的自适应变阻抗控制方法

Adaptive variable impedance control methods in dynamic environments

  • 摘要: 针对机器人接触性作业存在环境建模不精确导致接触力跟踪波动的问题,提出一种动态环境下的自适应变阻抗控制方法。所提出的控制方法根据接触力反馈信息建立惯性参数的自适应控制率,并对阻尼更新率动态调节,避免接触阶段的力超调,同时减小稳态跟踪阶段的力跟踪误差。基于Matlab/Simulink搭建仿真模型,与经典的定阻抗控制在平面、斜面及正弦曲面环境下进行对比实验,实验结果表明该方法相对经典定阻抗控制,在恒定期望力下力跟踪稳态误差至少减少2.33 N,超调量至少降低97.9%,期望力动态变化也具有更小的超调和稳态误差,在刚度突变时振荡次数少,能够很好地适应接触环境位置动态变化、刚度参数不准确、力动态变化的情况。

     

    Abstract: Aiming at the problem of contact force tracking fluctuation caused by inaccurate environment modeling in robot contact operation, an adaptive variable impedance control method in dynamic environment was proposed. The proposed control method establishes the adaptive control rate of the inertial parameters according to the contact force feedback information and dynamically adjusts the damping update rate to avoid the force overshoot in the contact phase and reduce the force tracking error in the steady state tracking phase. The simulation model is built based on Matlab/Simulink and compared with the classical fixed impedance control in the plane, inclined plane and sinusoidal surface environment. The experimental results show that compared with the classical fixed impedance control, the proposed method can reduce the steady-state error of force tracking by at least 2.33 N and the overwork by at least 97.9% under constant expected force. The desired force dynamic changes also have smaller overshoot and steady-state errors, and fewer oscillation times when the stiffness changes abruptly, which can well adapt to the dynamic changes of the contact environment position, inaccurate stiffness parameters, and dynamic changes of the force.

     

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