Design+of+decoupling+Smith+control+for+multivariable+system+with+time+delays.pdf

J. Cent. South Univ. Technol. (2011) 18: 473−478
DOI: −011−0720−8

Design of decoupling Smith control for multivariable system with time delays

HUANG Can(黄灿), GUI Wei-hua(桂卫华), YANG Chun-hua(阳春华), XIE Yong-fang(谢永芳)

School of Information Science and Engineering, Central South University, Changsha 410083, China

© Central South University Press and Springer-Verlag Berlin Heidelberg 2011


Abstract: In order to solve the decoupling control problem of multivariable system with time delays, a new decoupling Smith control
method for multivariable system with time delays was proposed. Firstly, the decoupler based on the adjoint matrix of the
multivariable system model with time delays was introduced, and the decoupled models were reduced to first-order plus time delay
models by analyzing the amplitude-frequency and phase-frequency characteristics. Secondly, according to the closed-loop
characteristic equation of Smith predictor structure, proportion integration (PI) controllers were designed following the principle of
pole assignment for Butterworth filter. Finally, using small-gain theorem and Nyquist stability criterion, sufficient and necessary
conditions for robust stability were analyzed with multiplicative uncertainties, which could be encountered frequently in practice.
The result shows that the method proposed