On estimation of approximate inverse models of block-oriented systems
2015 (English)In: Proceedings of the 17th IFAC Symposium on System Identification, 2015, 1226-1231 p.Conference paper (Refereed)
This paper concerns the estimation of approximate (linear) inverse models of block-oriented systems and the presented results give an improved understanding of these approximations. The estimated inverse is intended to be used as a pre- or postdistorter of the original system and a good inverse model would thus be one that, when used in series with the original system, produces a signal that resembles the original input. An inverse model of a nonlinear system can either be estimated in the standard way (from input to output) and then inverted, or directly (from output to input). This choice will affect the model. In the general case, the two modeling approaches will lead to different models, which will be shown for Hammerstein and Wiener systems. However, for a noise-free Hammerstein system with a white Gaussian input, the two approaches will result in the same model, up to a constant. When the two models are not equal, and the goal is to use the inverse as described above, it can be beneficial to estimate an approximate inverse directly. It will also be illustrated in an example how the inverse estimate can be used to get a nonparametric estimate of the nonlinearity in a block-oriented system.
Place, publisher, year, edition, pages
2015. 1226-1231 p.
, IFAC-PapersOnLine, ISSN 2405-8963 ; 48(28)
system identification, nonlinear systems, block-oriented systems, inverse systems
IdentifiersURN: urn:nbn:se:liu:diva-122292DOI: 10.1016/j.ifacol.2015.12.299OAI: oai:DiVA.org:liu-122292DiVA: diva2:865432
17th IFAC Symposium on System Identification, Beijing, China, October 19-21, 2015