Discrete Dynamics in Nature and Society
Volume 2010 (2010), Article ID 569850, 16 pages
doi:10.1155/2010/569850
Research Article

Robust Controller Design Using the Nevanlinna-Pick Interpolation in Gyro Stabilized Pod

Bin Liu,1,2 Chang-Hong Wang,1 Wei Li,1 and Zhuo Li3

1Space Control and Inertial Technology Research Center, Harbin Institute of Technology, Harbin 150001, China
2School of Electric Information Engineering, Northeast Petroleum University, Daqing 163318, China
3College of Earth Science, Northeast Petroleum University, Daqing 163318, China

Received 22 September 2010; Accepted 13 November 2010

Academic Editor: Li Xian Zhang

Copyright © 2010 Bin Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The sensitivity minimization of feedback system is solved based on the theory of Nevanlinna-Pick interpolation with degree constraint without using weighting functions. More details of the dynamic characteristic of second-order system investigated, which is determined by the location of spectral zeroes, the upper bound 𝛾 of 𝑆 , the length of the spectral radius and the additional interpolation constraints. And the guidelines on how to tune the design parameters are provided. Gyro stabilized pod as a typical tracking system is studied, which is based on the typical structure of two-axis and four-frame. The robust controller is designed based on Nevanlinna-Pick interpolation with degree constraint. When both friction of LuGre model and disturbance exist, the closed-loop system has stronger disturbance rejection ability and high tracking precision. Numerical examples illustrate the potential of the method in designing robust controllers with relatively low degrees.