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常规主动刹车系统采用在线辨识跑道特征的算法,但仍需依赖摩擦模型先验知识,难以应对复杂跑道工况.为克服上述问题,提出一种滑模极值搜索控制策略并应用于无人机全电式自主刹车系统.考虑电动作动机构非线性特性,建立系统的状态空间模型并合理简化为严格反馈形式,采用超扭曲算法估计结合系数的梯度,结合反馈线性化控制律得到刹车压力参考值,证明此控制作用下可实现对未知最优滑移率的渐近跟踪.采用反演控制的思想设计无抖振滑模控制器实现对参考刹车压力的跟踪.利用Lyapunov方法获得系统的渐近稳定性条件并分析控制参数对系统的影响.半实物仿真试验结果表明控制策略的有效性.
Conventional active braking system adopts the algorithm of online identification of runway characteristics, but it still needs to rely on the prior knowledge of friction model and is difficult to deal with complex runway conditions.In order to overcome the above problems, a sliding mode extremum search control strategy is proposed and applied to UAV All-electric autonomous brake system Considering the nonlinearity of the electric actuator, the state space model of the system is established and simplified to the strict feedback form, the super-warping algorithm is used to estimate the gradient of the combined coefficient, and the feedback linearization control law is used to obtain the brake pressure reference Value, it proves that the asymptotic tracking of the unknown optimal slip ratio can be realized under this control. The chattering-free sliding mode controller is designed to track the reference brake pressure with the idea of inversion control. The Lyapunov method Near-stability conditions and the influence of control parameters on the system are analyzed.The results of the semi-physical simulation show that the control strategy is effective.