Mathematical model of the Magnetic Suspension and Balance System for wind tunnel aircraft models

Аuthors

Vyshkov Y. D.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: yuvyshkov@mail.ru

Abstract

The Magnetic Suspension and Balance System (MSBS) for wind tunnel models was created as the result of the collaboration of the Moscow Aviation Institute (MAI) and the Central Aero-Hydrodynamic Institute (CAGI). The MSBS was created for carrying out aerodynamic tests of the models with six degrees of freedom in a subsonic wind tunnel with the section size of the instrumentation chamber equal to 40 cm × 60 cm. Wind tunnel MSBS is being developed in order to solve the main problems of aerodynamics, which cannot be solved in the presence of the effects of mechanical support devices, and study the base pressure, etc.
The tested models are the bodies of rotation with the diameter of about 4 cm and 40 cm length (or less). The models could be equipped with a tail unit and low-aspect-ratio wings. A ferromagnetic core made of electrotechnical steel with the shape of a cylindrical tube was placed inside the model.
The MSBS has 6 degrees of freedom. The model angle of attack could vary within the limits from −45 to +45 degrees. The range of flow speed variation was 0 − 100 m/s. The MSBS includes 7 electromagnets. All electromagnets except for the one, which creates the longitudinal force, are installed symmetrically relative to the test section of the wind tunnel. The electromagnet, which creates the longitudinal force, is installed on one side of the test section of the wind tunnel. The shape and position of this electromagnet provides easy access to the model and a good visual observation. Each electromagnet is equipped with a separate system of current control. The upper coils of electromagnets have a common ferromagnetic core, which helps to increase the vertical force. The lower coils do not have a common core in order to obtain the required moments of forces and the necessary forces by extreme attitude testing.
The position and the attitude of the model are measured by the optical position sensor. The optical system includes the compensation of the influence of the change in the intensity of the light, which falls on the model.
The control system uses the control algorithms, which provide the maximal area of stability of the suspended object under the conditions of the control power limitation.
The roll stability around the longitudinal axis of the model is achieved by placing a permanent magnet inside the model. To provide the roll damping the magnet is fixed inside the model by a spring and a damp cell.
Investigation and improvement of the Magnetic Suspension and Balance Systems and techniques requires the creation of a mathematical model, which would correspond to the real system sufficiently. This paper adduces such a model, which is intended for simulation of the Magnetic Suspension and Balance Systems for a wind tunnel. The paper also presents some results of the research of the dynamic properties of the mathematical model.

Keywords:

wind tunnel , magnetic suspension, electromagnets, mathematical model of the stabilizing system, wind tunnel aircraft model

References

1. Vyshkov Ju.D., Kovalnogov S.A., Usachev V.N., Shapovalov G.K. Uchenye zapiski CAGI, 1986, vol. XVII, no. 4, pp. 94−97.
2. Vyshkov Ju.D., Jumagazin B.A. Electrichestvo, 1984, no. 8, pp. 73−74.
3. Kuzin A.V., Vyshkov Ju.D. Izvestija Vuzov. Priborosnroenie, 1987, no. 11, pp. 44-49.

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