Modelling of an industrial control loop for concentration control using Omola, an object-oriented modelling language, is described. The major modelling effort has been made to make a complete nonlinear model of the pneumatic positioner-actuator of the control valve in the loop. A library of several friction models has also been developed. These models have been used to describe friction in the con

In this paper an adaptive system to control processes affected by dead-zone nonlinearities, based on a nonlinear compensation, has been studied. The adaptive control schemes ensure boundedness of the close-loop signals and reduce the tracking error. The main goal was to understand the problem in details, analyzing the different situations and difficulties that this nonlinear compensation might in

The report discusses mathematical modeling of thermal components, such as heat exchangers and control valves. A flexible model library for simulation has been developed. The object-oriented and equation-based modeling language Omola is used to describe the components in mathematical terms. The library of models can be used to build models of more complex thermal systems, such as heat exchanger uni

This thesis treats several problems in control of piecewise linear systems. A parameter estimation algorithm for piecewise linear systems is presented. Some problems with the algorithm are discussed and suggestions with regard to the input requirements are made in order to overcome the problems encountered. A self-tuning regulator for piecewise linear systems is presented, using pole placement des

We have, on Alfa Laval's behalf, tried out suitable control equipment to control the Brazed Heat Exchanger in steam applications. Reports have come in from several countries telling us about problems occuring when trying to control steam. Damages have arisen (often as a crack in the first or the last plate) due to fatigue caused by pressure variations in the steampipe. We have through a market

The purpose of thesis has been to examine the possibility of implementing feeling to a submarine steering gear, by studying how different combinations of feedback factors affected the person who is steering. The study has been made with the help of a yawing simulator that was designed solely for this purpose.

Recent high quality printers pose interesting questions on how to reproduce images taken by a video camera. A modern ink jet plotter has typically a resolution four times better than a good video camera. Pixel replication and bilinear interpolation give reasonable results, but have a tendency to blur the image. In contrast to these blurring phenomena, it is well known that the apparent visual qual

The purpose of this thesis has been to examine the possibilities of implementing feeling to a submarine steering gear.