21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-1.4.5

A MATHEMATICAL MODEL OF AFFINE NONLINEAR SYSTEM FOR HELICOPTER FLIGHT DYNAMICS

Yang C., Hong G.
Beijing University of Aeronautics and Astronautics, China

Keywords: mathematical model, affine nonlinear system, helicopter flight dynamics

Preparing for further study of nonlinear system and nonlinear control law of helicopter, a math model of affine nonlinear system (ANSM) for helicopter flight dynamics is established in this paper. In choosing sub-models and giving assumptions, a principle; which all control variables in motion differential equations must be linearized and precision of model must be guaranteed simultaneously, should be abided. The model is used to calculate the conditions of static trim in steady straight flight and dynamic responses to different control inputs for UH-60A helicopter. The results agree with flight test and have considerable precision comparing to Ames GENHEL model. So, the math model are validated, and the theories and methods that have been used in the math model are all proven out. With better precision and analytic formulas, the affine model in this paper can also be used for real and non-real time digital simulation, and for other studies of helicopter flight dynamics.

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