【作者】 汪庆；

【导师】 王永；

【作者基本信息】 中国科学技术大学 ， 导航、制导与控制， 2011， 硕士

【摘要】 直升机具有空中悬停、垂直起降和贴地飞行等独特的飞行能力,因此近年来在军事和民用方面得到了广泛的应用。但直升机飞行动力学复杂,引起直升机开环不稳定、轴间高度耦合、系统参数摄动明显等问题,需要设计良好的飞行控制系统来辅助驾驶员完成飞行任务。而作动器饱和是直升机控制系统设计中不可忽视的一个问题,因为作动器饱和会影响直升机飞行性能,甚至引起响应发散。本文主要在作动器饱和约束下,研究了直升机的两步法抗饱和控制与直接抗饱和控制问题。首先建立了直升机全飞行包线线性化模型。在分析了直升机运动与建模的特点后,根据UH-60黑鹰直升机运动学方程和配平参数,在具有代表性的前飞速度处建立了直升机线性化模型,并运用该模型分析了直升机模态和开环操纵响应。然后研究了直升机基于线性矩阵不等式（LMI）的两步法抗饱和控制方法。提出了一种能适用于直升机这样的开环不稳定系统的两步法抗饱和控制方法,通过回路变换与乘数理论减少抗饱和保守性,证明了该方法的L₂稳定性,并将抗饱和问题等价为相应的LMI。针对直升机,第一步在不考虑饱和约束的情况下设计了H∞回路成形内外回路控制器,内回路实现全姿态控制和各通道间解耦,外回路实现速度跟踪;第二步考虑饱和约束,采用本文的两步法抗饱和控制方法求取抗饱和补偿器,弱化饱和引起的闭环性能退化,实现了直升机姿态与速度的良好控制。最后研究了直升机的直接抗饱和控制问题,设计了直升机基于神经网络与伪控制隔离的抗饱和自适应控制器。针对动态逆对未建模误差和参数不确定等逆误差较为敏感的问题,采用非线性单隐层神经网络结合鲁棒项补偿逆误差,并基于Lyapunov方法证明了系统的渐近稳定性。采用伪控制隔离方法处理作动器饱和,实现了自适应单元与作动器饱和特性之间的隔离。随后运用本文的抗饱和自适应控制方法对直升机俯仰角进行控制,分析了系统性能,并进一步研究了直升机三姿态和速度控制。更多还原

【Abstract】 Helicopter has been widely used in military and civilian in recent years, for its special flight capability, such as hover in air, vertical take off and sticking to ground. However, due to the complexity of helicopter flight dynamics, helicopter is open-loop unstable, highly coupled in shafts and significant perturbation with system parameter. Therefore, an excellent flight control system is required to assist the driver complete flight mission. And actuator saturation is a problem can not be ignored in helicopter control system design, for actuator saturation will affect helicopter flight performance, ever lead to response divergence. In this paper, with consideration of actuator saturation, two-step anti-windup control and direct anti-windup control of helicopter was studied.Firstly, all envelope linear model of helicopter was established. After analysis of motion and modeling characters of helicopter, according to motion equations and trim parameters of UH-60 Black Hawk helicopter, the linear model of helicopter was established in some representative forward speed. Analysis of mode and open-loop control response of helicopter was made by this model.Then, two-step anti-windup control of helicopter based on Linear Matrix Inequality （LMI） was studied. A two-step anti-windup control approach was proposed, which can be applied to open-loop unstable systems such as helicopter. Conservation of anti-windup compensator was reduced by loop transformation and multiplier theory. L₂ stability of the proposed anti-windup control system was proved, and anti-windup problem was equivalent to corresponding LMI. First step, without consideration of saturation constraints, H∞loop shaping inner and outer loop controller was given. The inner loop achieved all attitude control and channels decoupling, while the outer loop realized velocity tracking. Second step, with consideration of saturation constraints, the design of anti-windup compensator was proposed to reduce close-loop performance degradation caused by saturation. Then, attitude and velocity excellent control of helicopter was achieved.Finally, direct anti-windup control of helicopter was studied. Anti-windup adaptive controller of helicopter based on neural network and pseudo-control hedging was proposed. The single hidden layer neural network with robust term were used to compensate inversion error, for dynamic inversion is sensitive to inversion error such as un-modeled error and parameter uncertainty, and system asymptotic stability was proved based on Lyapunov method. And with consideration of actuator saturation, isolation of adaptive element and actuator saturation is achieved by pseudo-control hedging. Then, the proposed anti-windup adaptive control method was applied to control of helicopter pitch angle, and system performance was analyzed. Control of helicopter three attitudes and velocity were also studied.更多还原