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飞机在起飞和着陆过程中刹车系统工作的可靠性和效率的提高,对提升整个飞行周期的安全性有着重要的意义.针对不同的跑道状况(干、湿等)、跑道材质(沥青、软土)或温度等条件下,飞机轮胎与跑道之间的结合力会存在较大差异而直接影响刹车效果甚至有效性的问题,采用与速度相关的动态LuGre摩擦力模型表示结合力,将未知的跑道状态映射到结合力模型参数,通过对模型参数进行估计,达到对跑道状态进行识别的目的.首先建立飞机机体和机轮动力学模型,使用状态观测器对结合力模型中不可测量的内部摩擦状态变量进行估计,并由自适应律获得当前跑道状态对应的模型参数,而后在线求解结合力模型的伪稳态模型得到结合系数最大值及相应的滑移率,将此滑移率作为控制系统的跟踪目标,利用反馈线性化思想构造前馈控制器进行防滑刹车控制,最后通过仿真验证控制效果.
The reliability and efficiency of the braking system during take-off and landing are of great importance to improving the safety of the entire flight cycle. For different runway conditions (dry, wet, etc.), runway materials (asphalt, soft soil ) Or temperature, the binding force between the aircraft tire and the runway will have a big difference and will directly affect the braking effect or even the effectiveness. The dynamic LuGre friction model related to speed expresses the binding force, and the unknown runway State is mapped to the parameters of the cohesion model, and the purpose of recognizing the runway status is achieved by estimating the parameters of the model.Firstly, the aircraft body and the wheel dynamics model are established, and the state observer is used to measure the unmeasured internal friction state Variables are estimated and the model parameters corresponding to the current runway state are acquired by the adaptive law. Then, the maximum value of the conjugate coefficient and the corresponding slip rate are obtained by solving the pseudostationary model of the binding force model online, and the slip rate is taken as the control system Tracking target, using feedback linearization to construct feedforward controller for anti-skid braking control, and finally through simulation Control effect.