Dynamical referencing of coordinate measurement machines and machine tools

该项目的主题是通过将全息测量原理与基于模型的控制器设计技术相结合，在保持精度的情况下，对测量机器和机床的动态特性进行成功的研究。开发和评估的摄像系统将被扩展，以便用单个光学传感器同时跟踪空间中的两个发光点标记。我们的目标是实现高达每秒500帧的采集和测量标记位置的空间分辨率约为1微米，使用建立的多点投影方法与计算机生成的全息图。这允许在测量机器或机床中首次精确和直接测量工具和工件之间的相对位置。为了保证高的空间分辨率，将研究基于全息多点投影技术的超精密标定技术，从而提高信噪比。这种新的测量技术提供了一种直接确定工具和工件之间相对位姿的方法，但通常使用的驱动轴编码器的时间和空间分辨率仍然更好。然而，这些编码器仅提供具有较大不确定性的间接测量，因为它们位于驱动轴处。因此，来自摄像机系统和编码器的测量信号的融合是所提出的项目延续的主题，使得可以第一次以高空间和时间分辨率获得刀具和工件之间的决定性相对位置。该估计用于建立高精度的跟踪控制系统。在此过程中，将研究通过双级致动器提高跟踪精度的方法。

Subject of the proposed project continuation is the extension of the successful investigations on the enhancement of the dynamic properties in measuring machines and machine tools under preservation of the accuracy by combining holographic measurement principles with model-based controller design techniques.The developed and evaluated camera system will be extended in order to simultaneously track two luminous point markers in space with a single optical sensor. The goal is to achieve up to 500 acquired frames per second and a spatial resolution of approximately 1 um for the measured marker position using the established multipoint projection method with computer-generated holograms. This permits a precise and direct measurement of the relative position between tool and workpiece in measuring machines or machine tools for the first time. In order to ensure a high spatial resolution, ultra-precise calibration techniques which are also based on the holographic multi-point projection technique will be investigated, resulting in an improved signal-to-noise ratio.The novel measurement technique provides a direct determination method for the relative pose between tool and workpiece, but the temporal and spatial resolution of typically used encoders at the drive axes is still better. However, these encoders provide only an indirect measurement with a larger uncertainty since they are located at the drive axes. Thus, the fusion of the measurement signals from the camera system and the encoders is subject of the proposed project continuation, such that the decisive relative position between tool and workpiece can be obtained with both high spatial and temporal resolution for the first time. This estimate is used to establish a high-precision tracking control system. In the course of this, methods for improving the tracking accuracy by dual-stage actuators will be investigated.