Weighting function selection in H design

I. Postlethwaite, Mi Ching Tsai, Da Wei Gu

Research output: Contribution to conferencePaperpeer-review

5 Citations (Scopus)


We examine an H$ mixed sensitivity design problem formulated to achieve good disturbance rejection and tracking properties as well as robust stability. A two degree-of-freedom controller is used, then, as is well known, the tracking objectives can be considered separately. A major concern in H design is the selection of weighting functions to satisfy the design specifications. In this paper we give conditions on the weights which guarantee the optimization problem is well-defined; describe how a constrained optimization can be posed so that improper and unstable weights can be used; describe the effect the weights have on various design objectives; show how an appropriate selection of weights can reduce a 2-block optimization problem (requiring an iterative solution) to a 1-block problem (with a closed-form solution); give an illustrative example. In particular we show how the pole-zero cancellation phenomenon in H design can be exploited or prevented by a suitable choice of weight, and how an optimal controller with a given frequency roll-off can be obtained.

Original languageEnglish
Number of pages6
Publication statusPublished - 1991
EventProceedings of the 11th Triennial World Congress of the International Federation of Automatic Control - Tallinn, USSR
Duration: 1990 Aug 131990 Aug 17


OtherProceedings of the 11th Triennial World Congress of the International Federation of Automatic Control
CityTallinn, USSR

All Science Journal Classification (ASJC) codes

  • Engineering(all)


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