| In aircraft design and operation maintenance, aircraft wheel shimmy is a common and serious trouble. It has been a long time since the research on aircraft wheel shimmy started, but now this trouble can not be avoided absolutely. So it is significative and useful to study the stability analysis of the nose wheel shimmy.This paper studies the linear and nonlinear stability analysis of the nose wheel shimmy. For linear shimmy analysis, the analysis models of the nose wheel shimmy respectively considering single wheel, corotating dual wheel, ballast mass, the rigid motion of fuselage and the elastical vibration of fuselage are studied. On the basis of above study, an analysis model of the nose wheel shimmy considering discorotating dual wheel is presented. Structural-Torsion Shimmy and how to fix on the range of damping are studied also. And the influence of every kind of landing-gear structural and tire characteristics parameters on shimmy stability are analysed.For nonlinear shimmy analysis, the analyses of effects of backlash, Coulomb friction and the velocity-squared damping on shimmy are carried out by the describing fuction method, while shimmy amplitudes is less than backlash or greater than backlash or the nonlinear dampingMθ1=Ct·(θ|·)1+Cd(θ|·)2·sgn((θ|·)1)is considered in shimmy system.A stability analysis software system of aircraft nose wheel shimmy is developed with considering the analysis models presented in this paper. The shimmy stability analysis of a type of aircraft is carried out, and results fulfil need. It proves that the software system is feasible and has a good man-machine conversation environment, and improves the accuracy and the speed of the shimmy analysis, and is useful to avoid shimmy in designing new aircrafts and maintenancing aircrafts in use.
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