Recursive Estimation of Time Delay in Thermodynamic Process

An on-line estimation method based on standard recursive least squares and the minimum cost function is presented and applied to estimate thermodynamic process-a model of two orders rational transfer function plus a time delay. The algorithm relies on the fact that if the continuous time model has a delay or anticipation shorter than one sampling time, then a real negative zero arises in the corresponding sampled system. By inspection of the phase contribution of this zero, the value of the fractional delay is recursively updated. Other parameters and integral time delay can be obtained by minimizing the cost function in two-step estimation algorithm. Simulation results illustrate the performances of the algorithm.