Modal multirate control for scaled bilateral system taking relative velocity resolution into account

Macro-Micro bilateral manipulation is a remote control with scaling factor of position/force between master (macro) and slave (micro) system. Normally, bilateral control based on acceleration control can realize not only high performance of force transmission because of the utilization of reaction force observer (RFOB), but also accurate tracking of position because of disturbance observer (DOB). However, implementation of scaling factor makes the unbalance between master system and slave system in the sense of relative velocity resolution, which makes the performance of bilateral system deteriorated. This paper proposes a multirate and different time resolution controller for scaled bilateral system, which can realize high performance of position tracking and force transmission. In this paper, experiments and Fast Fourier Transform (FFT) analysis of estimated disturbance force by DOB are given to confirm the effectiveness of proposed controller.