基于L1自适应律的尾坐式飞行器悬停位置控制

Position control of a tail-sitter MAV based on L1 adaptive controller in hover stage

针对一款飞翼布局的尾坐式垂直起降飞行器,研究了悬停阶段的位置控制问题。小型飞行器质量、惯量小,具有纵向横向耦合严重、难以精确建模以及对扰动敏感等特点。首先,建立包含不确定性的非线性动力学模型,通过整合将其改写为一个不含不确定的标称系统和一个非线性非匹配的不确定性两部分,使用级联形式的非线性动态逆架构进行标称系统控制器的设计,显式的期望动力学表达使其更易与L1自适应控制器结合。接着使用L1自适应控制器对非线性非匹配的不确定性进行补偿,以便提高系统鲁棒性,改善瞬态性能。为减小运算负荷,便于工程实现,使用计算更轻量的比例型自适应律进行L1自适应控制器设计。数值仿真验证了所设计控制器具有良好的位置和高度指令跟踪能力。

This study investigates the design of a position controller for a tail-sitter micro aerial vehicle（MAV）during the hover stage.Relative small mass and moment of inertia make this kind of aircraft have coupling issues between longitude and lateral,disturbance sensitive and hard to model accurately.Nonlinear dynamic models including uncertainties are built first,the systems are then divided into the combination of an uncertainty-free nominal system and a nonlinear unmatched uncertainty.The cascaded nonlinear dynamic inversion controller is used to control the uncertainty-free system to guarantee the good command tracking ability.Explicit express of the desired dynamics makes this architecture more appropriate to integrate with the L1 adaptive controller.The L1 adaptive controller is then used to compensate for the nonlinear unmatched uncertainties to improve robustness and transient performance of the system.In order to reduce the complexity of operation and be easy to realize in engineering,the proportional adaptation law is used as the architecture of the L1 adaptive controller because of its relative low computation consumption.Simulation results verify the good command tracking ability in position and altitude of the controller.