In hardware-in-the-loop (HIL) experimental environment, a local softening character of the emulated cutting force is observed during the emulation of turning, which affects the stability properties of the process. The real workpiece is substituted by a dummy one that is clamped to the real main spindle. It is excited in the lateral direction by an electromagnetic actuator. The position of the dummy workpiece is monitored by contactless laser-based sensors to close the feedback loop. The previous and the present position of the workpiece is stored to attain the effect of surface regeneration. The desired cutting force characteristic is calculated by means of a high performance real-time computer. The experimental results gained for the linear loss of stability of the process and for the spindle speed dependent dynamics leads to the conclusion that the dominant frequency decreases as the virtual depth of cut and thus the emulated cutting force increases. This is identified for a wide range of real spindle speeds and virtual depth of cuts. The measurement results are supported by theoretical stability analysis and the variation of the dominant frequency is tracked by means of the unexpected local softening nonlinearity of the electromagnetic actuator emulating the real cutting forces, which are also confirmed analytically. These results are needed in future development of a portable HIL system, to analyse chatter phenomena in the presence of cutting force nonlinearities and to test specific cutting tools before prototyping.

在硬件在环（HIL）实验环境中，在车削仿真过程中会观察到仿真切削力的局部软化特性，这会影响过程的稳定性。实际工件由夹紧在实际主轴上的虚拟工件代替。它被电磁致动器沿横向方向激励。虚拟工件的位置由基于非接触式激光的传感器监控，以关闭反馈回路。存储工件的先前位置和当前位置以获得表面再生的效果。所需的切削力特性可通过高性能实时计算机进行计算。对于过程稳定性的线性损失以及与主轴速度有关的动力学所获得的实验结果得出这样的结论，即主频率随着切削的虚拟深度而减小，因此模拟切削力增大。可以在各种实际主轴速度和虚拟切削深度中识别出这一点。测量结果得到理论稳定性分析的支持，并且通过模拟实际切削力的电磁执行器意外的局部软化非线性来跟踪主频率的变化，这也得到了分析确认。在便携式HIL系统的未来开发中需要这些结果，以便在存在切削力非线性的情况下分析颤动现象，并在进行原型设计之前测试特定的切削工具。