This classic magnetic levitation control problem is now presented in a
new and innovative form. A 25mm diameter, hollow steel sphere is suspended in
space with visually appealing results and convenient time constants. Both
analogue & digital control solutions are implemented.
Convenient sockets on the enclosure panel allow for quick changes of
analogue controller gain and compensation components. The equipment is
self-contained in analogue mode, with built-in power supply. In the digital
mode the system operates within a LabVIEW™ environment which allows
the system parameters to be determined and the system to be modelled.
Once the digital controller parameters have been determined, the
controller can be used to run the hardware and the actual control performance
can be seen and analysed. Using LabVIEW™ together with the detailed
training manuals supplied by Feedback and an Advantech PCI card [which creates
an impressive digital control system development environment] the user is
guided through the design process using Phenomenological process models,
Dynamics analysis, Discrete models identification, Controller design,
Controller tests on the model, Controller implementation in real-time
applications, Implementation of various control strategies, Data visualisation,
The Phenomenological process models are designed in SIMULINK™ to
provide initial models for the user to test. Model linearization is then
discussed and the use of simple dynamics analysis - like bode diagrams poles
and zeros maps are introduced.
To obtain accurate models Identification procedures incorporating LabVIEW™ functions
are described. The user has a chance to go step-by-step through the discrete
models identification. One of the ’obtained models’ is used for the Controllers
design and PID control is explained.
A guide is given for PID controller design, testing, tuning and
implementation on the model. Root locus technique is used to illustrate the
changes that PID controller tuning inflicts on the control system performance.
The designed controllers are prepared in SIMULINK™.