Large angle maneuvering control for missiles based on improved Terminal sliding mode method

Based on compound sliding surface and disturbance rejection mechanism, a novel design approach of nonsingular Terminal sliding mode (NTSM) controller is proposed for large angle maneuvering control during an air-to-air missile intercepting a target in the rear hemisphere of the carrier. Firstly, the mathematical model of an air-to-air missile equipped with reaction-jet control system (RCS) is established considering the aerodynamic uncertainties. Subsequently, a missile attitude control law is designed by the traditional NTSM method. On this basis, taking original states far from equilibrium during large angle maneuvering into account, a compound sliding surface is adopted to accelerate the convergence of control system. To solve the problem of severe chattering caused by the aerodynamic uncertainties at high angle of attack, extended state observer (ESO) methodology is introduced to online estimate and compensate the system uncertainties. Furthermore, the stability analysis to the proposed method demonstrates the finite time convergence property of the control system. Eventually, the designed controller is applied to the large angle maneuvering control for agile turn of air-to-air missile. Simulation results reveal that the proposed method is able to make the convergence faster and effectively attenuate chattering caused by unmodeled dynamics.