Operational Modal Analysis on a Six-Degree-of-Freedom Parallel Manipulator: Reproducibility, Excitation and Pose Dependency

In machining applications knowledge of structural response is key when optimizing the productivity. For six degrees of freedom parallel kinematic manipulators the response can be highly pose dependent. Mapping the response throughout the workspace becomes excessively labour intensive using traditional techniques, such as experimental modal analysis and so far accurate structural dynamic models are not convincing. This contribution covers experimental work using operational modal analysis with shaker excitation to map the response in multiple poses in the workspace of a 6-UTU parallel manipulator. The future prospects of applying output-only modal analysis are better and faster modal analysis which can support correct modelling of vibrational response. This contribution provides insight regarding reproducibility of operational modal analysis results, how excitation with shakers affect the results and whether pose dependent structural response is measurable using the technique.