基于非线性动态逆的大迎角飞行控制律设计

研究飞机大迎角飞行优化控制问题。为了用非线性动态逆方法进行大迎角飞行控制律设计,首先建立具有大迎角条件下强非线性、非定常迟滞、不对称的力与力矩等气动特性的六自由度非线性飞机模型。然后将非线性动态逆方法与奇异摄动理论相结合,并将飞机状态划分为快慢回路,分别应用非线性动态逆方法进行了飞行控制律设计。最后,通过控制分配将计算得到的三轴力矩指令转化为相应的舵面与推力矢量偏转指令,并进行了仿真验证。仿真结果表明,设计的飞行控制律具有优良的大迎角控制效果。     

飞行器不确定性建模与μ-H∞鲁棒动态逆控制

针对动态逆方法作为一种先进飞行器控制方法因需被控对象精确的数学模型而难以保证算法鲁棒性的问题,在深入研究飞行器的不确定性模型基础上,将动态逆方法作为鲁棒控制的内环,对模型不确定性进行外环鲁棒控制补偿.在传统H∞控制基础上进行了μ综合的分析与设计,并进行了最差情况分析.从仿真结果可以看出,这种方法既保证了动态逆方法的鲁棒性,又提高了整体控制性能.     

奇异摄动非线性系统的鲁棒自适应控制

应用Ｌｙａｐｕｎｏｖ稳定性判据结合微分几何角线性化理论,给出一种具奇异摄动的可线性化非线性系统的鲁棒自适性控制方法,并给出了仿真实例。     

基于非线性动态逆的姿态跟踪控制

当遇到非线性系统时可以利用传统的控制策略将其转化为线性系统进行处理,但是当系统的非线性度很高的时候,传统的控制策略就无能为力了,为了在飞行控制领域解决上述问题,引入了动态逆控制方法。首先确定一种非线性动态逆控制规律在飞行器上的应用,同时考虑到了惯性参数的不确定性和气动力矩的不确定性,实际是一种非线性的时变系统,为了改善全局稳定性,可以通过六自由度的仿真保证系统稳定,证明控制规律的有效性。     

反标架规范化控制器的鲁棒性能

研究反标架规范化控制器的鲁棒性能问题,以结构奇异值SSV(Structured Singular Value)为工具,将对象、系统开环传递函数和控制器以奇异值分解形式参数化,就方向性和耦合性引起的困难分别进行了讨论,得到了使系统保持鲁棒性能所需要的关于开环传递函数和控制器参数的充分条件,为反标架规范化结构鲁棒控制器设计提供了理论依据.     

基于鲁棒模糊控制理论的BTT导弹动态逆控制

将模糊控制理论应用于BTT导弹动态逆系统控制中,设计了BTT导弹控制系统鲁棒模糊控制器.首先应用动态逆系统方法设计BTT导弹控制器,然后用参数化线性模糊逻辑系统逼近动态逆控制器中的不确定项,并设计了自适应律以调整参数的变化,最后根据Lyapunov稳定性定理,证明了所提出的方法能保证BTT导弹控制系统是渐近稳定的,系统的跟踪误差将收敛到零.仿真结果表明,设计的控制器,对参数和外界扰动等不确定因素具有较强的鲁棒性和自适应性.     

基于自适应逆的飞机空投纵向控制系统设计

针对现代飞机空投时对系统稳定性与鲁棒性的要求,采用自适应逆的控制方法对飞机纵向姿态保持系统进行了控制律设计;首先基于飞机动力学与运动学方程,建立了飞机空投的纵向非线性数学模型,然后分析了空投时所产生扰动对飞机稳定性的影响,并应用自适应逆的方法设计了飞机的纵向控制系统,最后对某型飞机纵向控制系统的输出特性以及姿态保持的效果进行了仿真验证;仿真结果表明,设计的控制系统响应迅速、跟踪精确,具有良好的控制效果和抗干扰能力。     

基于变结构理论的高超音速飞机纵向逆飞行控制

针对高超音速飞机模型的高度非线性、强耦合、参数不确定等特点，提出了基于变结构理论的动态逆控制方法．该方法将逆控制的非线性解耦能力与变结构理论的强鲁棒性能有机结合，确保了高超音速飞机飞行的纵向稳定性，改善了其控制性能．仿真研究表明该控制方法对于高超音速飞机是可行的．     

鲁棒飞行控制系统的逆标架正规化设计

本文讨论了飞行控制系统的逆标架正规化设计理论和方法,证明了正规传递函数阵具有相同特征轨迹的鲁棒稳定性定理,并用飞行控制系统的设计实例说明了这种方法的应用和优点.     

基于非完整移动机器人动态模型的鲁棒输出跟踪

提出一种基于非完整移动机器人动态模型的鲁棒跟踪控制算法。在系统存在模型不确定性但满足“匹配条件”的情况下,设计了一种滑动控制器。仿真结果表明,当系统的质量、转动惯量、结构参数等存在较在误差时仍能实现精确跟踪,具有良好的鲁棒性。     

Dynamic inversion for multivariable non-affine-in-control systems via time-scale separation

This paper presents a tracking design methodology applicable to multivariable non-affine-in-control systems. The main focus is on solving the tracking problem for non-linear systems whose dynamics depend non-linearly on the control input. The latter is designed to be faster than the main system dynamics. Using singular perturbation theory along with the Lyapunov stability theorems, it is shown that the proposed controller approximates an unknown dynamic inversion based solution with bounded errors, provides closed-loop stability, and solves the tracking problem with bounded errors. Simulations illustrate the theoretical results.     

Nonlinear generalised dynamic inversion for aircraft manoeuvring control

The nonlinear control problem of aircraft trajectory tracking is tackled in the framework of multiple linear time-varying constrained control using the newly developed paradigm of generalised dynamic inversion. The time differential forms of the multiple constraints encapsulate the control objectives, and are inverted to obtain the reference trajectory-realising control law. The inversion process utilises the Moore–Penrose generalised inverse and the associated nullspace projection, and it predictably involves the problematic generalised inversion singularity. Thus, a singularity avoidance scheme based on a new type of dynamically scaled generalised inverses is introduced that guarantees both asymptotically stable tracking and singularity avoidance. The steady-state closed-loop system allows for two inherently noninterfering control actions working towards a unified goal to exploit the aircraft's control authority over the entire state space. One control action is performed by the particular part of the control law on the range space of the transposed constraint matrix, and it works to impose the prescribed aircraft constrained dynamics. The other control action is performed by the auxiliary part of the control law on the complementary orthogonal nullspace of the constraint matrix, and it provides aircraft's global inner stability using the concept of perturbed feedback linearisation. Numerical simulations of an aggressive multiaxial aircraft coordinated manoeuvre verify the efficacy of designing nonlinear flight control systems via this methodology.     

Set membership inversion and robust control from data of nonlinear systems

A set membership method for right inversion of nonlinear systems from data is proposed in the paper. Both the cases where the system to invert is known or unknown and therefore identified from data are addressed. The method does not require the invertibility of the regression function describing the system and ensures tight bounds on the inversion error. In the case of unknown system, the method allows the derivation of a robust right‐inverse, guaranteeing the inversion error bound for all the systems belonging to the uncertainty set which can be defined from the available prior and experimental information. Based on such a set membership inversion, two methods for robust control of nonlinear systems from data are introduced: nonlinear feed‐forward control (NFFC) and nonlinear internal model control (NIMC). Both the design methods ensure robust stability and bounded tracking errors for all the systems belonging to the involved uncertainty set. Two applicative examples of robust control from data are presented: NFFC control of semi‐active suspension systems and NIMC control of vehicle lateral dynamics.Copyright © 2013 John Wiley & Sons, Ltd.     

基于神经网络的鲁棒自适应逆飞行控制

提出基于在线神经网络的超机动飞行自适应动态逆鲁棒控制方法.超机动飞行的基本控制律采用非线性动态逆方法设计,对于建模误差或者控制面损伤等因素导致的不确定性逆误差采用神经网络进行自适应补偿.通过动态逆控制律简化计算和飞机控制面故障自适应修复的仿真表明,神经网络通过在线补偿逆误差,能够有效降低非线性动态逆对模型准确性的要求,增强控制系统的鲁棒性.     

Robustification of input redundant feedback systems using robust actuator weighting in the control allocation problem

In this article, a new methodology for robust actuator weighting in the control allocation (CA) problem of input redundant feedback systems is addressed. The methodology is based on the control structural properties of the plant which were previously used for control configuration selection. Robust performance (RP) measures including H _∞ norm and structured singular value of the closed-loop system are used in this article. The capability of the approach is proven with application to lateral dynamics control of the vehicle over-actuated with front and rear steering systems. Employing the RP measures, it is concluded that the vehicle feedback control with front steering angles gives superior RP properties in comparison with the feedback loop of the rear steering angles. Based on these results, the penalty weightings in the cost function of the CA unit are determined. Simulation results based on nonlinear seven degrees of freedom vehicle handling model show that the selection of penalty weightings in the CA unit based on the RP properties of the control inputs (front and rear steering angles) improves the RP of the closed-loop.     

Observer‐based adaptive robust control of a class of nonlinear systems with dynamic uncertainties

In this paper, a discontinuous projection‐based adaptive robust control (ARC) scheme is constructed for a class of nonlinear systems in an extended semi‐strict feedback form by incorporating a nonlinear observer and a dynamic normalization signal. The form allows for parametric uncertainties, uncertain nonlinearities, and dynamic uncertainties. The unmeasured states associated with the dynamic uncertainties are assumed to enter the system equations in an affine fashion. A novel nonlinear observer is first constructed to estimate the unmeasured states for a less conservative design. Estimation errors of dynamic uncertainties, as well as other model uncertainties, are dealt with effectively via certain robust feedback control terms for a guaranteed robust performance. In contrast with existing conservative robust adaptive control schemes, the proposed ARC method makes full use of the available structural information on the unmeasured state dynamics and the prior knowledge on the bounds of parameter variations for high performance. The resulting ARC controller achieves a prescribed output tracking transient performance and final tracking accuracy in the sense that the upper bound on the absolute value of the output tracking error over entire time‐history is given and related to certain controller design parameters in a known form. Furthermore, in the absence of uncertain nonlinearities, asymptotic output tracking is also achieved. Copyright © 2001 John Wiley & Sons, Ltd.     

Depth control of autonomous underwater vehicles using indirect robust control method

In this article, we propose a robust depth control design scheme for autonomous underwater vehicles (AUVs) in the presence of hydrodynamic parameter uncertainties and disturbances. The controller is designed via a new indirect robust control method that handles the uncertainties by formulating the uncertainty bounds into the cost functional and then transforming the robust control problem into an equivalent optimal control problem. Both robust asymptotic stability and optimality can be achieved and proved with this new formulation. The θ-D method is utilised to solve the resultant nonlinear optimal control problem such that an approximate closed-form feedback controller can be obtained and thus is easy to implement onboard without intensive computation load. Simulation results demonstrate that robust depth control is accomplished under the system parameter uncertainties and disturbances with small control fin deflection requirement.     

On performance recovery of robust dynamic surface control

Robust dynamic surface control (RDSC) is effective in alleviating the implementation difficulty of backstepping‐based multiple‐surface sliding control (MSSC) for a class of strict‐feedback nonlinear systems with mismatched uncertainties. However, the synthesis and analysis of the classical RDSC are conservative, which not only may lead to an impractical control law but also cannot fully reveal the technical nature of RDSC. This article provides a comprehensive study of a preferred RDSC law with an approximation of the signum function based on the singular perturbation theory. By formulating the control problem into a singular perturbation form, it is proven that the preferred RDSC recovers the performance of MSSC as the decrease of a filter parameter. The attractive features of the preferred RDSC revealed during the proposed synthesis and analysis include: (a) the control gain can be significantly reduced resulting in a sharp decrease of control energy and (b) the closed‐loop stability can be guaranteed by only decreasing the filter parameter. Simulation results have been shown to be consistent with the theoretical findings.     

逐点线性化后退区间最优控制在飞机非线性控制中的应用

常规线性飞控系统针对推力矢量飞机这样的多控制冗余、非线性MIMO系统,无法实现非线性控制．本文针对推力矢量飞机非线性系统,阐述了一种逐点线性化后退区间最优控制算法满足飞行品质要求．首先将作动器,飞行品质和逐点线性化的飞机线性模型综合实现在线建模,然后以飞行状态与预测状态之间的误差、作动器的位置限制和速率限制作为最优指标,最后以此为基础,根据最优控制原理计算当前时刻飞机最优控制指令,实现飞机非线性控制．采用国内某型号飞机气动数据验证此算法的鲁棒性和稳定性．