The ECOSSE Control HyperCourse
Introduction to Virtual Control Laboratory
Welcome to the Virtual Control Laboratory. The aim of this section of
the ECOSSE Control HyperCourse is to allow you to carry out actual
laboratory experiments on the computer.These have been modelled to be as
realistic as possible and the
documentation may include photographs of the actual experimental apparatus.
Nothing can replace the real, hands-on experience of lab work but as
class sizes increase and resources of time and money decrease some
problems are encountered, e.g. that students are able to carry out fewer
experiments or have to work in large groups.
The Virtual Control Laboratory can overcome these
problems.
- All students can now do every control experiment in their own time.
- Virtual experiments can be carried out either as a teaching aid before
actual physical lab experiments, or for comparison after these experiments.
- If some aspect of the process or system is not understood properly
then simulations can be used for clarification.
- It is possible to obtain results more rapidly than in a
physical laboratory and so more
examples can be tried.
Documentation
The laboratory manual briefly describes each experiment's aims and
some of the theory. A more in-depth description
is given with the actual experiment.
- The first part of the documentation for each individual experiment is
simply a list of the aims.
- This is followed by a more in-depth
discussion of the theory associated with that particular experiment.
Note that in some cases there are links back to the main text of
the coursework modules in the ECOSSE Control HyperCourse.
- Next
the experimental apparatus is shown. In most cases both a photograph of
the actual experimental rig and a diagrammatical representation is
given. Again this emphasises that the lab is based on actual
experiments.
- The fourth stage is the procedure. This outlines what
input parameters are required by the Fortran90 program and then what
results are generated in the form of graphs.
- Finally the user can run
the simulation ie. input the required data and look at the desired graphs.
Interaction
The user interacts with the computer through the use of html
forms. These take the format of a set of questions designed to obtain
the relevent data. This data is then used as input to a Fortran90
program which produces the output in a convenient format. Next the
output is turned into a graph which is subsequently viewed on the
browser.
The Experiments
The experiments have been split up into 3 sections, increasing in
difficulty.
Introduction To Control
The two experiments which make up this section are very basic. They
introduce the concepts of automatic control systems and control. At
this stage the user should get a feel for the qualitative aspects of
control i.e. what happens if the dead zone or proportional band is
increased or decreased, but not necessarily the quantitative aspects
i.e. the actual numbers do not matter as much.
Controller Tuning
By this stage the user is capable of quantitative analysis of the
controller. They are introduced to the Zeigler Nichols open and closed
loop tuning methods through simple interactive exercises. This is
followed by further examples in both methods.
On completing this section the user should understand fully how to tune
a controller and obtain the optimal settings.
Multiple Loop Control Systems
In this third section the user is introduced to the concept of multiple
loop systems and the RGA method of pairing up adjustments and
measurements. This section contains two different real-life simulations
- the blending of two streams in a tank and the control of a
distillation column.
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