Magnetic levitation through electromagnet has been held since 1930 with the purpose of studying the nonlinear behavior of this type of device. During this period, the methods used for magnetic levitation have been improved, particularly as regards control systems.

The most common method for magnetic levitation is based on the use of an electromagnet. The electromagnet is controlled by a magnet electrical current capable of suspending a particular metal object to a certain height in the vertical axis only with the electromagnetic field generated by electric current flowing in the solenoid. With the passage of a current I by the electromagnet, the ball is under the action of two forces: the gravitational force (weight) and the electromagnetic force produced by the coil, these forces working in opposite directions. In the equilibrium situation, the net force is zero, since the position of the sphere does not vary over time. Then: Fmag = PESF where Fmag is sufficient electromagnetic force produced by the electromagnet to balance the weight of the sphere or balancing force produced by the current.

For a long time it has been tested numerous types of position sensors (inductive, capacitive, optical), as were used for various types of drivers (amplifiers, thyristors, PID, computer control, RNA, etc.) in order to efficiently control the electromagnetic force needed to balance the system.

The dynamic of a magnetic Levitator system is a nonlinear system, where control (rewarding) should act on the dynamic balance of the metal object levitated in order to keep in balance the forces acting on the system. In figure 1 are shown the parameters involved in the dynamics of the system which are the mass of the sphere (m), the distance between the object and the electromagnet (x), the electric current flowing through the solenoid (i) and the voltage which is applied across the electromagnet terminals of the solenoid (V).

Thus, the dynamic equations can be written as follows:

At where:

ƒ is the electromagnetic force;

i is the current in the coil;

x is the distance between the electromagnet and the object;

V is the voltage at the solenoid of the electromagnet;

R is the resistance of the solenoid electromagnet;

L is the inductance of the solenoid electromagnet;

m is the mass of the object;

g is the acceleration of gravity.

It is observed that the [01] equations [02], [03] respectively represent, ball position and current in the electromagnet, ball weight, and inductance of the electromagnet.

References:

to BARBOSA, Luis Filipe Wiltgen, COSTA, Francisco EDF, LUDWIG, Gerson Otto, JUNIOR, Cairo Lucio Nascimento, Analog Control of a magnetic Levitator (MagLev) Simple Construction and Operation. 2004;

the GOMES, Rafael Ramos, SOTELO, Guilherme Goncalves, STEPHAN, Richard Magdalena, Development of a didactic system for Electromagnetic Levitation with the aid of the Finite Element Method. 2004.

the SANTANA, Marcos Silva, FERREIRA, Jossana Maria de Souza, SALAZAR, Andrés Ortiz, Educational Module of a magnetic Levitator. 2001.

Authors:

Dárcio Pig Farms

Hartus Gonçalves Barbosa

POSTED BY HARTUS TO 19:18

6 COMMENTS:

Anderson23 April 2009 10:43

Hi, very good this article.

How can I mount a device that homemade way for teaching purposes?

Thank you and congratulations

andersonnogueira2008@gmail.com

Answer

Professor26 June 2009 12:41

This comment was removed by the author.

Answer

Professor26 June 2009 12:41

Interesting videos, could have more content by the amount of references consulted. Note 4.5 (0 to 5).

Answer

Carlos Eduardo Weber28 September 2009 21:27

taking the equations 1 and 3, would like me to get a transfer function of X (s) / V (s)

Answer

Michelangelo Quirino12 August 2013 14:05

Hi, very good this article.

How can I mount a device of this home for teaching purposes?

Thank you and congratulations

miguel.a.quirino@gmail.com

Answer

Lorrana Lara15 August 2013 12:50

Hello, very nice article.

How can I make a Levitator such, for a job in college?

Thanks.

lorranalara20@gmail.com

Answer

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