PSICON—A simulation package for the design of digitally controlled systems

Abstract

A simulation language is described which is based on a block-oriented continuous systems simulator called PSI. Using the message-transfer capability of the multitasking operating system of a minicomputer, external digital control algorithms can be developed rapidly in Fortran, while retaining the advantages of a flow-chart based and precompiled structure of the continuous simulation language. The use of the package is illustrated with two examples. The first is an anaesthetics problem in which time-delay dynamics are controlled using an external Fortran programme comprising a Smith predictor plus a PID regulator. The second example is a self-tuning adaptive autopilot for ship steering. The package gives fast simulation and good interactive properties, with the external controller segments giving the required flexibility for a wide range of uses.

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