Hybird Nonlinear Control for Fighter With Center of Gravity Perturbation and Aerodynamic Parameter Uncertainty

Abstract

In this paper, a hybrid nonlinear control scheme combines nonlinear dynamic inversion (NDI) and adaptive sliding mode (ASM) control is proposed for high angle of attack fighter system with center of gravity perturbation and aerodynamic parameter uncertainty. By introducing the affine nonlinear model of inner loop angular velocity with center of gravity perturbation, an adaptive sliding mode control scheme based on the online estimation of radial basis function (RBF) neural network is designed, which can reduce the dynamic inversion error of NDI control and rapidly compensate the multi-coupled channel oscillation. The aerodynamic force and moment coefficients are estimated via the iterative weighted least squares (IRLS) method. The outer loop integral sliding mode (ISM) NDI controller is designed, which can be robust to disturbances and mismatched uncertainties through adjusting adaptive gain, and the rudder yaw chattering caused by the uncertainty of aerodynamic parameters is reduced simultaneously. The Lyapunov stability theory and Barbarat lemma prove the stability of the designed control scheme, and the effectiveness of the hybrid nonlinear control scheme is verified based on F-16 model.