Self-excited vibrations known as chatter are considered as the most detrimental issue in micro-turning processes. Occurring unpredictably, they adversely affect the tool life, productivity rate and surface quality of the machining processes. In this paper, a novel machining arm is modeled as a piezoelectric stacked rod which is subjected to a chatter force in the orthogonal micro-turning process. Due to the fact that machining processes are affected by various sources of uncertainties, H∞ robust control approach is used to suppress the chatter vibrations of the machining arm in the presence of tool wear and dynamic model parameter variations. Also, input control force of the system is provided by exciting the input voltage of piezoelectric layers of the rod. In order to be certain that the designed controller succeeds in suppressing vibrations of the effective structural modes, behavior of the first three modes of vibrations are considered in the final response of the machining arm. In the following, performance of the robust H∞ controller is compared with a modified PID controller. Simulation results show that the H∞ controller improves the robustness and performance of the system against uncertainties. The PID controller extends the stability region of the sharp tool and fails to achieve this purpose for the worn tool although its performance is acceptable in suppressing chatter vibrations.

中文翻译：

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压电叠片加工臂微车削过程颤振建模与主动控制

称为颤振的自激振动被认为是微车削过程中最有害的问题。它们的发生不可预测，会对加工过程的刀具寿命、生产率和表面质量产生不利影响。在本文中，一种新型加工臂被建模为压电堆叠杆，它在正交微车削过程中受到颤振力。由于加工过程受到各种不确定因素的影响，在刀具磨损和动态模型参数变化的情况下，采用H∞鲁棒控制方法来抑制加工臂的颤振。此外，系统的输入控制力是通过激励杆的压电层的输入电压来提供的。为了确保设计的控制器成功抑制有效结构模式的振动，在加工臂的最终响应中考虑了前三种振动模式的行为。下面，将鲁棒 H∞ 控制器的性能与改进的 PID 控制器进行比较。仿真结果表明，H∞ 控制器提高了系统对不确定性的鲁棒性和性能。PID 控制器扩展了锋利工具的稳定区域，但对于磨损的工具却没有达到这个目的，尽管它在抑制颤振方面的性能是可以接受的。鲁棒 H∞ 控制器的性能与改进的 PID 控制器进行了比较。仿真结果表明，H∞ 控制器提高了系统对不确定性的鲁棒性和性能。PID 控制器扩展了锋利工具的稳定区域，但对于磨损的工具却没有达到这个目的，尽管它在抑制颤振方面的性能是可以接受的。鲁棒 H∞ 控制器的性能与改进的 PID 控制器进行了比较。仿真结果表明，H∞ 控制器提高了系统对不确定性的鲁棒性和性能。PID 控制器扩展了锋利刀具的稳定区域，虽然它在抑制颤振方面的性能是可以接受的，但对于磨损的刀具却没有达到这个目的。