Title page for ETD etd-02102010-121259

Document Type Master's Dissertation
Author Badenhorst, Werner
Email werner.badenhorst@eng.up.ac.za
URN etd-02102010-121259
Document Title Optimal control on rock winder hoist scheduling
Degree MEng
Department Electrical, Electronic and Computer Engineering
Advisor Name Title
Prof X Xia Committee Chair
Dr J Zhang Committee Co-Chair
  • optimal load scheduling
  • load modelling
  • rock winders
  • model predictive control
  • constrained linear programming
Date 2010-04-14
Availability unrestricted

This dissertation addresses the problem of optimally scheduling the hoists of a twin rock winder system in a demand side management context. The objective is to schedule the hoists at minimum energy cost taking into account various physical and operational constraints and production requirements as well as unplanned system delays.

The problem is solved by first developing a static linear programming model of the rock winder system. The model is built on a discrete dynamic winder model and consists of physical and operational winder system constraints and an energy cost based objective function.

Secondly a model predictive control based scheduling algorithm is applied to the model to provide closed-loop feedback control. The scheduling algorithm first solves the linear programming problem before applying an adapted branch and bound integer solution methodology to obtain a near optimal integer schedule solution. The scheduling algorithm also compensates for situations resulting in infeasible linear programming solutions.

The simulation results show the model predictive control based scheduling algorithm to be able to successfully generate hoist schedules that result in steady state solutions in all scenarios studied, including where delays are enforced. The energy cost objective function is proven to be very effective in ensuring minimal hoisting during expensive peak periods and maximum hoisting during low energy cost off-peak periods. The algorithm also ensures that the hoist target is achieved while controlling all system states within or around their boundaries for a sustainable and continuous hoist schedule.

Copyright 2009, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

Please cite as follows:

Badenhorst, W 2009, Optimal control on rock winder hoist scheduling, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-02102010-121259/ >


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