Dual-rate sampled-data systems. Some interesting consequences from its frequency response analysis

Abstract

The main goal of this contribution is to introduce a new procedure in order to analyze properly SISO dual-rate systems (DRS) and to provide straightforward answers to some common general questions about this kind of systems. Frequency response analysis based on DRS lifting modeling can lead to interesting results about stability margins or performance prediction. As a novelty, it is explained how to understand DRS frequency response and how to handle it for an easy computation of magnitude and phase margins keeping classical frequency domain methods. There are also some repetitive questions about DRS that can be analyzed and answered properly using the results from this contribution: what the optimum relation between sampling periods is or what effects does delay have in a DRS . Every step is illustrated with examples that should clarify the understanding of the text.

A QFT approach to robust dual‐rate control systems

“…Also, a number of works have extended the switch decomposition method of Kranc to very general cases obtaining which has been called a generalized Bode diagram (GBD). 54,55 By using a GBD, it is possible to analyze the several harmonic components of a DR sampled system as interleaved fragments of the frequency response of a particular single-rate system. In the following, the lifted system SVD technique and, with some more detail, the GBD technique are applied to a DR control system to analyze its intersample behavior and motivate the QFT analysis and design technique to be developed in this work.…”

Multirate control strategies for avoiding sample losses. Application to UGV path tracking

“…Therefore, in the coprime case (assumed in this contribution), N y components are obtained. Using the T 0 resampling of each of these T y components, a T 0 pure sinusoidal is achieved (for details see [47]).…”

A QFT approach to robust dual-rate control systems

“…The frequency domain analysis of multirate systems may be performed by using singular value decomposition(SVD) of the lifted MIMO system. Also, a number of works have extended the switch decomposition method of Kranc to very general cases obtaining which has been called a generalized Bode diagram (GBD) [59,52]. By using a GBD, it is possible to analyze the several harmonic components of a DR sampled system as interleaved fragments of the frequency response of a particular single-rate system.…”