The effects of feedback delays on the performance of multivariable linear control systems

This short paper presents the sufficient conditions of stability of the linear systems with delays in such a form that they enable evaluation of the exponential upper bound of the transients of the system in question. Next, the paper yields a method of evaluation of a loss of the value of a quadratic performance index due to the delays in the system. Furthermore, the paper gives a proposal of an improvement of the system performance by use of the simple state variables extrapolator which anticipates the current stste on the basis of the delayed state observation. The numerical examples presented illustrate the theoretical considerations contained in the paper.