A Simple Event-Based PID Controller

A simple event-based PID controller is presented. It is shown that it is possible to obtain large reductions in CPU utilization with only minor control performance degradation. Simulations on a double-tank process are presented

Realization of Expert System Based Feedback Control

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Tools and Languages for Modeling and Optimization of Large-Scale Dynamical Systems

High-level modeling languages are receiving increased industrial and academic interest within several domains, such as chemical engineering, thermo-fluid systems and automotive systems. One such modeling language is Modelica. Modelica is an open language, specifically targeted at multi-domain modeling and model re-use. Key features of Modelica include object oriented modeling, declarative equation modeling, a software component model enabling acausal connections of submodels, as well as support for hybrid/discrete behaviour. These features have proven very applicable to large-scale modeling problems in various fields. This contribution gives an overview of a project targeted at i) defining an extension of Modelica, Optimica, which enables high level formulation of optimization problems, ii) developing prototype tools for translating a Modelica model and a complementary Optimica description into a representation suited for numerical algorithms, and iii) performing case studies demonstrating the potential of the concept

Trends in Software and Control

New software technologies are important for the future of control (and vice versa) in an age of increasing complexity. This paper discusses what are the trends

High-Level Grafcet and Batch Control

The application of Grafcet to supervisory control applications with special emphasis on batch control is described. Grafchart, a Grafcet based G2 toolbox is presented. An industrial application where it is currently used on-line is described. High-Level Grafcahrt is an extension of Grafchart that is based on High-Level Petri nets and Object-Oriented Programming. It increases the parameterisation and structuring possibilities of Grafchart. The SP88 draft batch control standard is shown to be well suited for representation by High-Level Grafchart