Tom Oomen


Research on Overactuation and Oversensing

In traditional rigid-body motion systems, the system mainly behaves as a rigid-body, i.e., a -2 slope in the frequency domain within the control bandwidth. Flexible dynamics are typically seen as high-frequent parasitic effects (and sometimes locally the gain of the controller is reduced through a notch-filter). This basically looks like

We envisage that next-generation motion systems will have flexible dynamics within the control bandwidth. Namely, increasing accuracy requirements will probably imply a larger frequency range over which the controller is active:

To make the situation even worse, we also foresee lightweight system designs to enable throughput requirements (this is probably best way to deal with F = Ma). This implies that the flexible dynamics will typically occur at lower frequencies (this is not an immediate consequence, see section 1.3 of Oomen, 2010). This leads to

To deal with these flexible dynamics, we are investigating the use of additional actuators and sensors. In particular, we want to actively control these flexible dynamics by adding stiffness and damping through feedback control. Therefore, we have used the identification and robust control design results and designed controllers that exploit this additional freedom. Interestingly, this turns out to have a very positive effect on the inferential performance. The results are described in the following publication.

Related work on the design of weighting functions (even if one does not have additional actuators and sensors at their disposal) are described in the following paper.

For a further treatment of these challenges in next-generation motion control, the introduction section of the following paper may be interesting:

Acknowledgement

The above results are in collaboration with many co-workers, both from TU/e-ME and industry.

Note that all figures shown on this page can be found in the mentioned papers. Please follow the guidelines regarding copyright and references when citing these.