The low-frequency chatter (LFC) of the robot body during milling severely constrains the machining efficiency. Taking the classical mode coupling mechanism as the underlying foundation, previous studies have developed various stability models to predict the LFC in robotic milling. However, the classical mode coupling mechanism has recently been proven to be applicable only to operations such as threading and boring, showing significant deviations in robotic milling. In response, this paper proposes a novel vibration feedback-based mode coupling (VF-MC) mechanism applicable to robotic milling based on robotic modal directionality, which describes the coupling and feedback process of modal vibration among multiple modes through dynamic cutting forces. The feedback process is modeled considering the time delay effect. The LFC can be judged by the trend of the amplitudes of the feedback vibrations. The effectiveness and efficiency of the VF-MC model for predicting the LFC are verified by comparing with the milling experiment results and the traditional mode coupling chatter model. Furthermore, the dynamical conditions for the LFC are investigated based on the VF-MC mechanism with the experimental evidence. The core contribution of this paper is to quantitatively reveal the feedback mechanism of low-frequency self-excited vibration among modes in robotic milling, and further develop the VF-MC model to efficiently predict the LFC. The code for the VF-MC model is available at .

中文翻译：

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一种新颖的模式耦合机制，通过提供振动反馈视角来预测机器人铣削中的低频颤振

铣削过程中机器人本体的低频颤振（LFC）严重制约了加工效率。以经典模态耦合机制为基础，以往的研究开发了各种稳定性模型来预测机器人铣削中的LFC。然而，经典模式耦合机制最近被证明仅适用于螺纹加工和镗孔等操作，在机器人铣削中显示出明显的偏差。为此，本文提出了一种基于机器人模态方向性的适用于机器人铣削的新型振动反馈模态耦合（VF-MC）机制，该机制描述了通过动态切削力的多模态之间的模态振动的耦合和反馈过程。反馈过程的建模考虑了时间延迟效应。 LFC可以通过反馈振动幅度的趋势来判断。通过与铣削实验结果和传统模态耦合颤振模型的比较，验证了VF-MC模型预测LFC的有效性和效率。此外，基于VF-MC机制和实验证据研究了LFC的动力学条件。本文的核心贡献是定量揭示机器人铣削模态间低频自激振动的反馈机制，并进一步开发VF-MC模型来有效预测LFC。 VF-MC 模型的代码可在 处获取。