Delay Independent Output Feedback Stabilization of Discrete-time Linear Systems with Bounded Input Delay

Bounded input delay frequently arises in control systems. The popular predictor feedback design requires the exact knowledge of the delay. Such a requirement on the availability of the delay knowledge poses challenges in the design of robust control laws when only the knowledge of an upper bound of the delay is known. We propose such a design in this paper. Based on the delay independent truncated predictor state feedback design, an observer based output feedback law is constructed that does not contain the exact value of the delay. For a general, possibly exponentially unstable, discrete-time linear system, the proposed output feedback law stabilizes the system as long as the delay does not exceed a certain amount. For a system with all open loop poles at z = 1 or inside the unit circle, a low gain feedback design enables the feedback law to handle any bounded time-varying delay.