无动力无人机跟踪下滑直线自适应非线性制导律设计
Design of Adaptive Nonlinear Guidance Law for Unpowered UAV Tracking a Gliding Line

以无人机失去推力后，如何使其跟踪一条给定下滑直线为研究背景，提出了一种跟踪下滑直线的自适应非线性制导方法。首先根据几何关系推导得到跟踪下滑直线的横纵向制导律，并证明了所得制导律的稳定性；然后考虑到无动力状态下横纵向制导之间的影响较为明显，为了提高系统的跟踪精度以及抗风扰动能力，将所得制导律转化为一个二阶黏滞阻尼振荡系统，从改善该振荡系统收敛速率的角度出发，设计了制导律的自适应方案。仿真结果表明，在无风和有风扰动的条件下，所提出的方法均可提高系统的跟踪精度。
For tracking a given trajectory when UAV lost power, this paper presents a method of nonlinear adaptive guidance for following a line. Firstly, according to the geometric relationship, longitudinal and lateral guidance laws are designed and their stabilities are proved. Secondly, considering the significant influence between longitudinal and lateral laws as well as promoting the tracking accuracy and the anti-wind ability, the guidance laws are transformed into the two-order viscous systems with damping and oscillation and then the adaptive schemes are designed in order to improve the convergence of the oscillating system. Finally simulation results show that the proposed method increases tracking accuracy, despite being constantly subjected to wind disturbance