Research of Smith Predictor Algorithm used in Large Time- Delay System

Professor Smith designed the famous Smith predictor in 1957 to solve the delay problem of systems. Now lots of institutes and engineers engaged in the research of Smith predictor, as it has become one of the most important solutions to control delay in large delay system, by adding smith predictor in the feedback loop of controlled process in large time-delay system, delay factors would be “separated” from other factors in delivery functions. In this paper we made some discussion about Smith predictor, put more emphasis on the formulation of the method, also a comparison between Smith predictor and Dahlin (another important solution to control delay, created by Eric Dahlin in 1968) is given. Based on the form discussion this paper also try to proposed a kind of modified Smith predictor, developed the details of relative formulation.