This paper investigates the control of a low cost vertical-axis maglev system for mechatronics and controls education. The tabletop maglev system consists of an electromagnetic coil that levitates a ferrous object using an infrared sensor to determine the object’s position. Based on the sensor output, the controller adjusts the coil current, thus changing the magnetic field controlling the levitated object’s position. A second electromagnetic coil is used to provide known disturbances. The paper develops the underlying theory for magnetic levitation and presents the results of experiments with classical controllers implemented both as analog circuits and in software-based virtual instruments. Analog controllers, such as PID-type controllers, were implemented as simple circuits on National Instruments’ Educational Laboratory Virtual Instrumentation Suite (NI-ELVIS) prototyping board. NI-ELVIS offers a LabVIEW-based prototyping environment for readily experimenting with different controller circuits. It consists of a multi-function data acquisition device and a custom-designed bench-top workstation with a prototyping board. In addition to analog control circuits, a suite of LabVIEW-based controllers were developed which offer in software a rapid way to change control strategies and gains and explore the effect on the physical system.

Volume Subject Area:
Dynamic Systems and Control
Topics:
Magnetic levitation, Control equipment, Circuits, Computer software, Electromagnets, Sensors, Virtual instrumentation, Analog circuits, Data acquisition, Education, Instrumentation, Magnetic fields, Mechatronics
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Design of PID Controllers Satisfying Gain Margin and Sensitivity Constraints on a Set of Plants
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Automatica
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40
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1
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111
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116
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