Nonlinear Optimal Feedback Regulation of Satellite Angular Monenta

Some important regulation properties of satellite angular momentum dynamics are investigated using a combination of reaction jets and flywheels. The optimal feedback controller is designed in such a way that system regulation, under large perturbations, to a proper bounded subset in Rn, is achieved by using reaction jets. Thereafter, flywheels are activated to bring the system to the rest (desired) state. The domain and the size over which reaction jets are active, as well as the corresponding fuel cost, are discussed. Further, the effect of linear as well as nonlinear optimal feedback regulators on system behavior is indicated. Finally, the range (in the state space Rn) over which the flywheels are capable of regulating the system is also studied.     

Adaptive block dynamic surface control for integrated missile guidance and autopilot

A novel integrated guidance and autopilot design method is proposed for homing missiles based on the adaptive block dynamic surface control approach. The fully integrated guidance and autopilot model is established by combining the nonlinear missile dynamics with the nonlinear dynamics describing the pursuit situation of a missile and a target in the three-dimensional space. The integrated guidance and autopilot design problem is further converted to a state regulation problem of a time-varying nonlinear system with matched and unmatched uncertainties. A new and simple adaptive block dynamic surface control algorithm is proposed to address such a state regulation problem. The stability of the closed-loop system is proven based on the Lyapunov theory. The six degrees of freedom (6DOF) nonlinear numerical simulation results show that the proposed integrated guidance and autopilot algorithm can ensure the accuracy of target interception and the robust stability of the closed-loop system with respect to the uncertainties in the missile dynamics.     

Roll-pitch-yaw autopilot design for nonlinear time-varying missile using partial state observer based global fast terminal sliding mode control

The acceleration autopilot design for skid-to-turn (STT) missile faces a great challenge owing to coupling effect among planes, variation of missile velocity and its parameters, inexistence of a complete state vector, and nonlinear aerodynamics. Moreover, the autopilot should be designed for the entire flight envelope where fast variations exist. In this paper, a design of inte-grated roll-pitch-yaw autopilot based on global fast terminal sliding mode control (GFTSMC) with a partial state nonlinear observer (PSNLO) for STT nonlinear time-varying missile model, is employed to address these issues. GFTSMC with a novel sliding surface is proposed to nullify the integral error and the singularity problem without application of the sign function. The pro-posed autopilot consisting of two-loop structure, controls STT maneuver and stabilizes the rolling with a PSNLO in order to estimate the immeasurable states as an output while its inputs are missile measurable states and control signals. The missile model considers the velocity variation, gravity effect and parameters’ variation. Furthermore, the environmental conditions’ dynamics are mod-eled. PSNLO stability and the closed loop system stability are studied. Finally, numerical simula-tion is established to evaluate the proposed autopilot performance and to compare it with existing approaches in the literature.     

ROBUST ADAPTIVE BANK-TO-TURN MISSILE AUTOPILOT DESIGN USING FUZZY CMAC NEURAL NETWORKS

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Missile autopilot design via functional inversion and time-scaled transformation

This paper presents a new approach to acceleration control of STT (Skid-To-Turn) missiles. In the design and stability analysis of our autopilot, we assume perfect roll-stabilization but consider fully all other nonlinearities of the missile dynamics including the coupling effect due to bank angle. Our autopilot controller consists of a partial-linearizing controller and a dynamic compensator. The partial-linearizing controller along with a time scaled transformation can convert the nonlinear missile dynamics to the so-called normalized system which is completely independent of Mach number and almost independent of air density. The dynamic compensator is designed based on this normalized system. This normalized system greatly simplifies the design process of an autopilot controller regardless of flight conditions. Our autopilot controller can provide fast and exact set-point tracking performance but without the slow-varying conditions on angle of attack and side-slip angle required often in the prior works.     

Missile autopilot design using quasi-LPV polynomial eigenstructure assignment

This paper presents the design of a missile autopilot over its flight envelop using quasi-linear parameter-varying polynomial eigenstructure assignment (PEA). The paper describes the extension of PEA to parameter-varying systems using a nonlinear missile model developed by Horton as an example. The autopilot is designed for a single-plane lateral acceleration control and a 5 degree of freedom (DOF) autopilot is also designed. Both lateral acceleration and augmented lateral acceleration outputs are considered. The lateral acceleration autopilot has nonminimum phase characteristics, and it is shown that the quasi-linear parameter-varying PEA approach can handle nonminimum phase systems unlike classic dynamic inversion techniques. Simulation results are presented over fast variations in Mach number and show that the design is robust.     

基于输出预测的姿控发动机控制律优化设计

针对带有侧向喷流姿控发动机和尾部气动舵的导弹,建立了系统动力学模型和运动学模型,并对模型进行了分析和简化;考虑到侧向过载输出响应快速性的要求,采用侧向喷流发动机提供姿态控制力矩快速建立过载。基于侧向喷流发动机的工作特点,采用Fliess展式得到侧向过载输出的预测和侧向喷流发动机推力放大因子的估计,并以此为基础,提出了以侧向喷流发动机为执行机构的姿态控制律优化设计方法,实现了对侧向过载的快速跟踪。仿真结果说明了所提出方法的有效性。     

Nonlinear hαMissile Longitudinal Autopilot Design with θ- D Method

In this paper, a new nonlinear H_infin control technique, called thetas-D H_infin method, is employed to design a missile longitudinal autopilot. The thetas-D H_infin design has the same structure as that of linear H_infin, except that the two Riccati equations that are part of the solution process are state dependent. The thetas-D technique yields suboptimal solutions to nonlinear optimal control problems in the sense that it provides an approximate solution to the Hamilton-Jacobi-Bellman (HJB) equation. It is also shown that this method can be used to provide an approximate closed-form solution to the state dependent Riccati equation (SDRE) and consequently reduce the on-line computations associated with the nonlinear H_infin implementation. A missile longitudinal autopilot design demonstrates the capabilities of thetas-D method. This new nonlinear H_infin design also shows favorable results as compared with the linear H design based on the linearized model.     

Time-Optimal Control of a Bounded Phase-Coordinate Process II: High-Order Systems with Multiple Control Inputs

This paper considers the problem arising from the design of an autopilot for a large booster. The motion-controlling actuators of the booster have both position and rate limits. The problem is formulated as a bounded phase-coordinate problem and analyzed by the ``backing out of the target' procedure. A method of constructing the optimal control is presented. An example of an oscillatory system with two control inputs is given, and the optimal control is expressed as an explicit time function.     

攻击地面固定目标寻的导弹的一体化制导与控制(英文)

This paper presents a scheme of integrated guidance and autopilot design for homing missiles against ground fixed targets. An integrated guidance and control model in the pitch plane is formulated and further changed into a normal form by nonlinear coordinate transformation. By adopting the sliding mode control approach, an adaptive nonlinear control law of the system is designed so that the missile can hit the target accurately with a desired impact attitude angle. The stability analysis of the closed-loop system is also conducted. The numerical simulation has confirmed the usefulness of the proposed design scheme.     

某型飞机角位移自动驾驶仪比例式控制规律设计与仿真

现代飞机越来越复杂的飞行任务对飞机控制系统性能提出了更高要求,而飞机控制系统性能的好坏与飞机自动驾驶仪控制规律设计的优劣关系密切.为此,对某型飞机自动驾驶仪的比例式控制规律进行了分析和设计,仿真研究了控制规律中的速率反馈及位置反馈的作用和选取原则,进而设计出性能良好的飞机角位移自动驾驶仪比例式控制规律.通过大量仿真比较...     

一种非线性末制导系统模型的精确线性化

针对未来高机动目标的拦截 ,运用非线性系统几何理论中的精确线性化方法 ,设计了一种空空导弹非线性末制导系统加速度指令。假设目标做逃逸机动 ,弹体 -自动驾驶仪响应用一个二阶环节描述 ,建立了导弹目标三维相对运动方程。根据终端约束直接选取系统输出阵 ,经动态反馈线性化 ,将非线性系统模型转化为线性方程 ,求得了目标任意机动时的非线性末制导系统的加速度指令。以纵向平面为例进行了仿真计算 ,结果表明该方法是行之有效的 ,得到的解可以用来改进导弹大离轴发射角时的进攻能力。     

导弹非线性控制系统设计方法研究

导弹过载输出跟踪控制系统是一个非最小相位系统.为了克服非最小相位特性造成的设计控制器的困难,介绍了一种新颖的导弹非线性控制算法--(系统)浸入和(流行)不变算法,将导弹的输出跟踪问题转化为系统的镇定问题.研究和仿真结果表明,这种方法是简单和实用的.     

基于非线性动态逆的SRLV再入段控制律设计

基于非线性动态逆理论,设计了亚轨道可重复使用运载器(SRLV)的再入控制律.首先,分析了SRLV再入段的数学模型,并给出了反作用推力控制系统(RCS)的控制模型;其次,将非线性动态逆方法与时标分离原则相结合,考虑飞行器姿态控制系统的外环角回路的慢变特性和内环角速度回路的快变特性,独立设计了两个回路的控制律;最后,为了增强系统的鲁棒性,分别在两个回路中引入了比例-积分反馈,有效地抑制了干扰力、力矩和非线性对消带来的逆误差.仿真结果表明,设计的控制律对SRLV再入段具有很好的控制效果.     

喷流对飞机尾流涡影响的试验研究

飞机产生的尾流涡,特别是大尺度的翼尖涡,对尾随其后的飞行器是非常有害的,本文旨在探索利用飞机发动机产生的喷流加速尾流涡消亡的方法。试验采用简化的飞机模型(有尾翼),建立了包含一对翼尖涡及一对反向旋转的尾翼涡(通过以负迎角安装尾翼得到)的4涡尾流系统。在无外来扰动的情况下,不同的尾翼设置下得到的尾翼涡对翼尖涡的作用效果不同,有的能导致翼尖涡提前消亡,有的则不能。考察了不同强度的喷流对不同4涡尾流系统的影响,且作为对比,对无尾翼(2涡系统)及无喷流下的各种情况也分别作了观测。试验在拖曳水槽中进行,运用体视粒子图像测速(SPIV)技术,观测了与模型拖曳方向垂直的、从机翼后缘到下游约45翼展间均布的一系列切面。结果表明:当喷流直接作用于涡时,其效果主要取决于两者之间的初始距离及相对强度;而当喷流作用于整个4涡尾流系统时,其引入的扰动对不同的系统均能起到一定程度的改善作用,这种作用的关键在于利用喷流优化对翼尖涡进行扰动的机制,而不仅仅取决于喷流的强度。     

Nonlinear autopilot for high maneuverability of bank-to-turnmissiles

This paper presents a novel approach to autopilot design for highly maneuvering bank-to-turn (BTT) missiles. In the design and performance analysis of the proposed nonlinear autopilot, all nonlinearities of missile dynamics including the coupling between roll, yaw, and pitch channels as well as the asymmetric structure of missile body are taken into full account. It is shown that through a kind of feedback linearization technique along with a singular perturbation-like technique, the input/output (I/O) dynamic characteristics of pitch, yaw, and roll channels are made linear, decoupled, and independent of flight conditions such as air density and missile velocity. In particular, the proposed autopilot controllers can provide excellent set-point tracking performance for roll and pitch channels while keeping the side-slip angle negligible. The generality and practicality of our approach are demonstrated through mathematical analysis and various simulation results using an ILAAT missile     

应用动态逆和时间尺度分离的BTT导弹控制

基于简化的ＢＴＴ导弹控制设计模型,应用非线性动态和时间尺度分离方法设计了一种非线性ＢＴＴ导弹自动驾驶仪,根据导弹实际的飞行高度和飞行速度,可以计算出导弹动力学系数的标称值,非线性动态逆法正是基于这些动力学系数的标移值,适适合于控制导弹作大空域飞行,六自由度仿真结果一步验证了方法是正确的与有效的。     

高速再入飞行器的制导与控制系统设计

 针对高速再入飞行器模型的快时变,强耦合,严重非线性的特点,采用反馈线性化方法,设计了自动驾驶仪;同时采用最优制导律设计与理想速度曲线相结合的方法,设计了能同时保证末端制导精度及速度方向、大小的制导律。最后,进行了六自由度仿真,结果表明 :设计的制导律及控制方案是合理、有效的,易于实现。     

Unstructured Euler solutions for missile aerodynamics

The purpose of this paper is to validate an unstructured 3D Euler flow solver, USER3D, against the experimental data and to compare it with a classical, structured, Euler solver, FLU3M of ONERA, on two different missile geometries at a Mach number of 2 and at various angles of attack up to 20 ° . The first geometry is a conventional missile with an ogive nose, a cylindrical body and four straight tail fins. The second geometry is a unconventional missile with a lenticular body and no tail fins. The present results are found to be in good agreement with these available results and the discrepancies observed between them are explained in detail. The present unstructured Euler code has proved to be accurate, fast and reliable for the aerodynamic design of conventional and unconventional missiles.     

基于自适应模糊滑模退步控制的直接力/气动力复合控制导弹自动驾驶仪设计

针对直接力/气动力复合控制导弹所具有的强耦合非线性特性,提出了一种基于自适应模糊滑模退步控制的自动驾驶仪设计方法.该方法利用自适应模糊系统所具有的万能逼近特性,对大迎角飞行过程中导弹动力学方程中存在的非线性函数进行逼近,并利用变结构控制所具有对干扰的强鲁棒性,构造误差系统滑模面,克服了逼近误差和外界干扰对控制系统的影响,实现了对大机动指令的精确跟踪.仿真结果表明,所设计的自动驾驶仪对过载指令有良好的跟踪效果,对模型不确定性和外界干扰具有鲁棒性.