Estimation of unobservable oscillations in sampled-data positioning systems

Unobservable oscillations of the controlled variable of a sampled-data positioning control system may degrade the performance and reliability of mechatronic product. The degree to which these oscillations are unobservable depends on the sampling frequency and the oscillation frequency. In this paper, we study the relationship between the oscillation frequency and the sampling frequency. We define the index of unobservable position based on its RMS amplitude to estimate effect of unobservable mechanical resonances on positioning control systems.