基于改进Terminal滑模的导弹大角度机动控制

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

针对空空导弹攻击载机尾后目标的大角度机动控制问题,提出一种基于复合滑模面与扰动抑制机制的非奇异Terminal滑模(NTSM)控制器设计方法。首先建立了包含有气动不确定性的直接力控制系统(RCS)空空导弹数学模型,并采用传统NTSM控制方法设计了导弹姿态控制律。然后,在此基础上,针对大角度机动时初始状态远离平衡点的问题,设计了一种复合滑模面以加快系统收敛速度。为解决大攻角下的气动不确定性导致的严重抖振问题,引入了扩张状态观测器(ESO)技术,实现了系统不确定量的在线估计与补偿。对所提方法的稳定性分析证明了系统的有限时间收敛特性。最后,将设计的控制器应用于空空导弹的敏捷转弯大角度机动控制,仿真结果表明新方法可以加快系统收敛速度,并能有效削弱未建模动力学造成的抖振现象。

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.