摘要：Time delay and sampling rate are two conditions that can make the design and implementation of soft sensors difficult due limiting the amount of information that can be obtained about the true process. Another wrinkle is the fact that neither of these two parameters is necessarily constant, with the value changing due to changes in the process. One such area of concern is the hot steel mill rolling process, where variable time delay can lead to problems with controlling the process. This paper seeks to examine the appropriate design of the bias update term of the soft sensor in light of variable, but known, time delays for a process operating with constant sampling rate and for both open- and closed-loop conditions. Using a mathematical approach to the problem, the previous results are extended to consider such a case. It is shown that if the process has variable time delay, then designing the bias update term in the soft sensor is very important, as it can have implications for process stability and trackability. Simulations are included to show the impact of different bias update terms.
