>From Bjarne.Foss@itk.ntnu.no Thu Feb 27 15:49:09 1997
Subject: Abstract PROST-seminar March 5, 1997

Mixed discrete event and continuous dynamic systems - control issues.

Bjarne A. Foss

Abstract:
Industrial control systems are generally comprised of discrete logic and
continuous controllers. The discrete logic performs functions
like starting process equipment and controlling low-level (or regulatory)
controllers. The discrete
logic may for instance switch between different controllers depending
on the operating conditions of a process.
Continuous controllers are used for regulatory control and for
supervisory control. On the regulatory level PID-controllers constitute
the typical continuous controllers. On the supervisory level continuous
controllers compute the setpoints for the regulatory
controllers using for instance an optimization algorithm. In our context
it is important to note that the discrete logic and
continuous controllers in many cases are closely coupled, hence they form
a hybrid dynamical system (HS). State-of-the-art
industrial design practice
is based on separately constructing the continuous and discrete
logic part of a control system. By this, the effect of the interaction
between the continuous and discrete
logic part is difficult to foresee during the design-phase.

The hybrid nature of a system may also originate from the controlled
system
itself. In chemical process control a process may change its
characteristics
abruptly. One example of this is the change between laminary and
turbulent flow conditions.

In the talk the following issues will be discussed:
1) The use of MPC on hybrid system. This includes theoretical results
and examples.
2) A possible method for designing the discrete control logic.


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Professor Bjarne A. Foss

Dept. of Engineering Cybernetics
Norwegian University of Science and Technology
N 7034 Trondheim - Norway
tel: +47-7359 4476
fax: +47-7359 4399
email: Bjarne.Foss@itk.unit.no
WWW: http://www.itk.unit.no/ansatte/Foss_Bjarne
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