Fundamental analysis of the modal control applied to over-actuated machine tools

高度动态的运动和过程力激励运动组件（例如滑动件）和下面的机器结构（例如框架）两者振荡。特别是对于轻质结构，会产生高振动幅度。机床中的振动会导致加工质量下降，因此必须将其降低到最低限度。为了能够在保持或改善运动质量的同时增加动力学，需要采取减少或避免振动的措施。一般来说，为了提高加工稳定性和颤振极限，应降低刀具中心点处的动态柔度。这可以通过增加系统的阻尼来实现，例如通过使用主动阻尼系统，所谓的主动阻尼装置。在大多数情况下，产生运动所需的驱动器和辅助致动器彼此独立地控制，而不考虑相互干扰。这使得机械耦合驱动器或附加致动器的选择和参数化特别困难。该研究项目的目的是使用模态控制来改善运动系统的动态特性，例如机床，其驱动器或致动器比运动自由度多。模态控制可以单独控制本征模，并通过所有可用的致动器以有针对性的方式阻尼激发的振荡。模态解耦旨在简化所有驱动器和执行器的控制器的参数化，并减少主动辅助系统对进给驱动器位置控制的反馈影响。为了实现高的动态轨迹精度并因此实现工件的高精度以及提高的工艺稳定性，目的在于提高进给轴的控制带宽并降低TCP处的动态柔量。

Highly dynamic movements and process forces excite both the moving assembly (e.g. slide) and the underlying machine structure (e.g. frame) to oscillate. High vibration amplitudes result especially for lightweight structures. Vibrations in machine tools lead to a deterioration of the machining quality and must therefore be reduced to a minimum. In order to enable an increase in dynamics while maintaining or improving the quality of motion, measures to reduce or avoid vibrations are necessary. In general, the dynamic compliance at the Tool Centre Point should be reduced in order to increase the process stability and the chatter limit. This can be achieved by increasing the system’s damping, for example by using active damping systems, so-called active damping devices. In most cases, the drives required to generate motions and the auxiliary actuators are controlled independently of each other and without taking mutual interference into account. This makes the selection and parameterisation of mechanically coupled drives or additional actuators particularly difficult.The aim of the research project is to use the modal control to improve the dynamic properties of motion systems, such as machine tools, which have more drives or actuators than degrees of freedom of movement. Modal control makes it possible to control eigenmodes individually and to damp the excited oscillations in a targeted manner with all available actuators. Modal decoupling is intended to simplify the parameterisation of the controllers of all drives and actuators involved and to reduce the feedback effect of the active auxiliary systems on the position control of the feed drives. An increased control bandwidth of the feed axes and a reduction of the dynamic compliance at the TCP is aimed in order to achieve a high dynamic path accuracy and thus a high accuracy at the workpiece as well as an increased process stability.