Abstract
This paper describes a new design method applicable to multi-input/multi-output sampled-data decoupled PID and I-PD control systems, and its simulation test results. A special feature of this design method is that the sampling period can be selected independently for every control loop.
The systematic design method makes it possible to decide the control parameters for every control loop and to eliminate the interactions between control loops simultaneously after selecting a sampling period for every control loop. This method is a model matching scheme especially based on process low frequency characteristics, which can be identified with relative accuracy.
Rise-times for an individual subprocess involved in a multi-input/multi-output process are generally different from one another. In most conventional multi-input/multi-output design methods, it is common to chose the same sampling period in all control loops. In such a case, the control computer is forced to work rapidly, since all control loops must be controlled with the sampling period suitable to the shortest rise-time subprocess.
In the new design method proposed here, it becomes possible to reduce the large amount of data processing while satisfying the design requirements, because the sampling period can be selected considering its rise-time for every subprocess.
