Control Performance of Three - Degrees - of - Freedom Micro - Moving Stage Using Motional Mode Decoupling Control together with Collocation Compensator

The piezo element as a representative displacement type actuator elicits a high-speed response. Recently, there has been much research carried out using this feature. In order to progress the control performance, we previously proposed the motional-mode-based decoupling control scheme for a three-degrees-of-freedom fine-motion stage with piezo elements. In the meantime, we proposed the collocation compensation method to realize the desirable positioning. As is well known, the controlled object on the condition that the actuators and sensors are collocated shows good control performance. Then, it is expected that the motional-mode-based decoupling control together with collocation compensation can realize the good performance all the more. However, this paper shows that the collocation compensation for the above control scheme has an effect on the only difference of the loop-gain for each motional mode. This result is useful for the mechanical design.