Adaptive augmentation of gain-scheduled controller for aerospace vehicles

This paper proposes an adaptive augmentation control design approach of the gain-scheduled controller.This extension is motivated by the need for augmentation of the baseline gainscheduled controller.The proposed approach can be utilized to design flight control systems for advanced aerospace vehicles with a large parameter variation.The flight dynamics within the flight envelope is described by a switched nonlinear system,which is essentially a switched polytopic system with uncertainties.The flight control system consists of a baseline gain-scheduled controller and a model reference adaptive augmentation controller,while the latter can recover the nominal performance of the gainscheduled controlled system under large uncertainties.By the multiple Lyapunov functions method,it is proved that the switched nonlinear system is uniformly ultimately bounded.To validate the effectiveness of the proposed approach,this approach is applied to a generic hypersonic vehicle,and the simulation results show that the system output tracks the command signal well even when large uncertainties exist.

Trajectory linearization control of an aerospace vehicle based on RBF neural network

An enhanced trajectory linearization control （TLC） structure based on radial basis function neural network （RBFNN） and its application on an aerospace vehicle （ASV） flight control system are presensted. The influence of unknown disturbances and uncertainties is reduced by RBFNN thanks to its approaching ability, and a robustifying itera is used to overcome the approximate error of RBFNN. The parameters adaptive adjusting laws are designed on the Lyapunov theory. The uniform ultimate boundedness of all signals of the composite closed-loop system is proved based on Lyapunov theory. Finally, the flight control system of an ASV is designed based on the proposed method. Simulation results demonstrate the effectiveness and robustness of the designed approach.

Research Progress in Aerospace Vehicles Propelled by Rocket-Based Combined Cycle Engines

The research status on the development of RBCC engines and corresponding aerospace vehicles around the world was overviewed,and the technical and application characteristics of RBCC technology were summarized.New development trends of combined cycle engines as well as space transportation were analyzed,and lastly,some suggestions on the development of RBCC and the relative aerospace vehicles were proposed.

Structural Deformation Monitoring of Flight Vehicles Based on Optical Fiber Sensing Technology:A Review and Future Perspectives

Structural deformation monitoring of flight vehicles based on optical fiber sensing(OFS)technology has been a focus of research in the field of aerospace.After nearly 30 years of research and development,Chinese and international researchers have made significant advances in the areas of theory and methods,technology and systems,and ground experiments and flight tests.These advances have led to the development of OFS technology from the laboratory research stage to the engineering application stage.However,a few problems encountered in practical applications limit the wider application and further development of this technology,and thus urgently require solutions.This paper reviews the history of research on the deformation monitoring of flight vehicles.It examines various aspects of OFS-based deformation monitoring including the main varieties of OFS technology,technical advantages and disadvantages,suitability in aerospace applications,deformation reconstruction algorithms,and typical applications.This paper points out the key unresolved problems and the main evolution paradigms of engineering applications.It further discusses future development directions from the perspectives of an evolution paradigm,standardization,new materials,intelligentization,and collaboration.

面向“总师型”人才培养的航天飞行器设计课程创新建设

航天飞行器设计是航空宇航科学与技术相关专业本科生的专业核心课程,以培养“总师型”后备人才基本能力和素养为教学目标。航天飞行器设计涉及要素多、概念多、学科耦合强,强调综合性、系统性和创造性。该文讨论航天飞行器设计课程的四个主要教学难点,结合西北工业大学办学目标,详尽地阐述课程创新建设思路。课程在知识体系、教学方法、教学资源方面持续改革,构建“国防战略牵引-航天思政引入-工程案例分析-虚拟仿真强化”的创新教学模式,论述课程创新建设具体实施过程。通过多维度评价与反馈,课程创新建设效果良好,有力支撑总体专业骨干和总师后备人选培养。

基于分数阶滑模控制的无人机轨迹跟踪控制器设计

四旋翼无人机在农业、工业和国防等领域广泛应用,但其复杂的系统特性和对扰动的敏感性使得控制变得困难。首先,考虑分数阶方法具有良好的鲁棒性以及调节灵活性的优点,将整数阶积分滑模面和改进的分数阶指数趋近律相结合,设计出了一种新的分数阶积分滑模控制器。然后,将所设计的分数阶积分滑模控制器应用于四旋翼无人机轨迹跟踪控制问题。仿真结果表明,所提控制器作用下的四旋翼无人机进行轨迹跟踪时响应速度快、无超调,且对外界干扰具有较强的鲁棒性。

基于自适应EKF的空天飞行器再入段大气参数估计方法

针对空天飞行器再入段计算虚拟大气参数时,风速状态系统噪声和导航系统量测噪声具有时变特性导致滤波精度下降问题,提出一种基于自适应EKF的大气参数估计方法。首先,基于气动模型下的动力学方程组,建立风速和大气参数估计模型;其次采用Sage-Husa自适应滤波方法对风速状态系统噪声和导航量测噪声进行自适应调整,并且针对可能存在的滤波发散问题,引入滤波发散判据,调整滤波过程参数,提高了滤波稳定性。最后进行了仿真验证,仿真结果表明,所提出的自适应EKF滤波方法具有较好的风速和大气参数估计精度和收敛稳定性,其中在风向、真空速和侧滑角估计精度上较EKF和传统Sage-Husa滤波算法均提高了20%以上。

Design and Analysis of Biomimetic Nose Cone for Morphing of Aerospace Vehicle

Morphing capability is absolutely vital for aerospace vehicle to gain predominant functions of aerodynamics, mobility and flight control while piercing and re-entering the atmosphere. However, the challenge for existing aerospace vehicle remains to change its structure of nose cone agilely. This paper carries out a lot of observational experiments on honeybee＇s abdomen which enhances the flight characteristics of honeybee by adjusting its biomorphic shape. A morphing structure is adopted from honeybee＇s abdomen to improve both the axial scalability and bending properties of aerospace vehicle, which can lead to the super-maneuver flight performance. Combined with the methods of optimum design and topology, a new bionic morphing structure is proposed and applied to the design of morphing nose cone of aerospace vehicle. Furthermore, simulations are conducted to optimize the structural parameters of morphing nose cone. This concept design of biomimetic nose cone will provide an efficient way for aerospace vehicle to reduce the aerodynamic drag.

Multi-scale design and optimization for solid-lattice hybrid structures and their application to aerospace vehicle components

By integrating topology optimization and lattice-based optimization,a novel multi-scale design method is proposed to create solid-lattice hybrid structures and thus to improve the mechanical performance as well as reduce the structural weight.To achieve this purpose,a two-step procedure is developed to design and optimize the innovative structures.Initially,the classical topology optimization is utilized to find the optimal material layout and primary load carrying paths.Afterwards,the solid-lattice hybrid structures are reconstructed using the finite element mesh based modeling method.And lattice-based optimization is performed to obtain the optimal crosssection area of the lattice structures.Finally,two typical aerospace structures are optimized to demonstrate the effectiveness of the proposed optimization framework.The numerical results are quite encouraging since the solid-lattice hybrid structures obtained by the presented approach show remarkably improved performance when compared with traditional designs.

Robust optimization of control command for aerospace vehicles with aerodynamic uncertainty

To reduce the design burden of Aerospace Vehicles(ASVs)control systems,this paper proposes a multi-constrained robust trajectory optimization method,which provides a good front-end input for the control system.Differ from the conventional aircraft,some control performance of ASVs is not only related to the model parameters,but also affected by the flight status.Therefore,the robust optimization method combines this characteristic of ASVs,sets the control performance as one of the optimization objectives,and considers the influence of parameter uncertainty.In this method,the polynomial chaos expansion algorithm is used to transform the trajectory optimization problem with uncertain parameters into the equivalent deterministic robust trajectory optimization problem.Finally,compared with traditional deterministic trajectory optimization methods to illustrate the effectiveness of proposed control optimization method.

基于高斯过程回归的空天飞行器多精度气动建模方法

为了满足空天飞行器在初步设计阶段宽速域、大空域模型的需求,将传统工程估算方法和计算流体动力学(CFD)数值模拟方法分别作为低精度和高精度气动数据来源,基于高斯过程回归模型提出独立于构型的空天飞行器气动性能多精度气动建模方法.在工程估算方法中,以面元法为基础,建立空天飞行器气动力快速估算模型.在CFD数值模拟中通过求解三维可压缩Euler方程实现空天飞行器气动高精度计算.将所提出的多精度气动建模方法应用于FTB外形的双参数气动建模问题中,通过对比分析,发现所提出的多精度气动模型的预测精度、稳定性均优于用同等数量高精度样本构建的单精度代理模型的,预测的相对误差小于1%.将多精度气动模型作为该空天飞行器再入问题气动数据来源,对比分析单、多精度建模方法对再入轨迹仿真的影响,发现所提出的空天飞行器多精度气动建模方法能够更加快速、准确地给出轨迹仿真所需的气动数据.

先进聚合物基复合材料电阻植入焊技术研究进展

先进聚合物基复合材料(APC)是实现航空航天装备轻量化的重要结构材料,而制造效率低、成本高、耗能严重等因素阻碍了APC的进一步扩大应用。电阻植入焊(RIW)技术具有设备简单、效率高、节能环保、适合大型曲面结构连接等优点,是能够替代传统的胶接工艺实现APC结构件的绿色制造、再制造、循环利用的革新性技术之一。本文综述了APC电阻植入焊工艺及应用技术的研究进展,介绍了APC电阻植入焊技术面临的挑战,系统归纳总结了热塑性复合材料RIW原理、电阻植入体类型、焊接工艺参数优化、热固性复合材料RIW原理以及RIW在大型APC结构件制造中的应用技术等,指出了APC的RIW目前存在涉及材料设计、工艺优化和夹具制造等方面的问题。在未来,热塑性复合材料(TPC)结构的RIW技术相关的研究有望集中在发展更高强度的焊接黏结剂、设计新型结构的发热元件(HE)和改善黏结剂与HE的界面结合强度等方面,以提高接头的承载能力;加强RIW接头力学本构模型、疲劳强度以及服役寿命的研究;针对特定APC部件开展焊接设备和夹具的研究,推动RIW工程化,填补国内在该方面的空白。

基于控制效益估计的空天飞行器自主控制重构(英文)

Future aerospace vehicles （ASV） are designed to fly in both inner and extra atmospheric fields, which requires autonomous adaptability to the uncertainties emanated from abrupt faults and continuously time-varying environments. An autonomous control reconfiguration scheme is presented for ASV to deal with the uncertainties on the base of control effectiveness estimation. The on-line estimation methods for the time-varying control effectiveness of linear control system are investigated. Some sufficient conditions for the estimable system are given for different cases. There are proposed corresponding on-line estimation algorithms which are proved to be convergent and robust to noise using the least-square-based methods. On the ground of fuzzy logic and linear programming, the control allocation algorithms, which are able to implement the autonomous control reconfiguration through the redundant actuators, are put forward. Finally, an integrated system is developed to verify the scheme and algorithms by way of numerical simulation and analysis.

TRRE发动机关键技术分析及推进性能探索研究

对TRRE发动机关键技术难点及技术途径进行了初步分析,对北京动力机械研究所原理样机研制进展进行了简要介绍,并结合原理样机流道设计与数值仿真研究获得的性能数据,开展了TRRE发动机推进性能探索研究,初步验证了TRRE发动机在兼具加速、巡航、机动等方面的性能优势。研究结果表明,在适当兼顾低马赫数大推力需求和Ma=6纯冲压工况高比冲需求的情况下,发动机在宽马赫数工作范围具有较大范围、灵活便捷的推力调节能力,可满足高低速通道平稳接力需求,表现出极具优势的加速、机动飞行和高马赫数巡航的适应性。

临近空间高超声速飞行器关键技术及展望

随着各国对提高军队通信、反应和作战能力的需求与日俱增,发展临近空间高超声速飞行器技术的重要性愈发明显。综述了临近空间高超声速飞行器国内外的发展现状与趋势,系统全面地分析了发展临近空间高超声速飞行器的关键技术,包括总体设计技术、气动力和气动热技术、高温长时间热防护技术、高精度GNC技术、有效载荷抛撒技术以及发动机技术。在此基础上,最后提出了适合我国国情的临近空间高超声速飞行器技术的发展设想。

航天电连接器振动可靠性试验与分析

以Y1 1X 2 2 2 1圆形电连接器为研究对象 ,通过对电连接器进行失效物理分析、加速寿命试验和试验数据的统计处理 ,求得了电连接器在随机振动应力作用下的可靠性参数估计值 。

结构强健的Al2O3-SiO2气凝胶的制备及可重复使用性能

通过纳米晶组装技术,构筑了Al2O3-SiO2复合气凝胶;利用不同组分耐温性的差异,经过热处理过程得到了骨架强健的Al2O3-SiO2气凝胶.研究了不同配比及热处理温度对材料微观结构和组分的影响,确定了最佳制备条件,得到了比表面积为123. 9 m^2/g,密度为0. 25 g/cm^3,导热系数为0. 029 W·m^-1·K^-1的气凝胶材料.在泡水和冰冻等极端环境下,气凝胶材料未发生结构的破坏,模拟10次重复隔热应用(800℃,30 min)后导热系数保持不变.该隔热性气凝胶的开发有望解决未来飞行器隔热材料需重复使用的技术瓶颈,为开发新型气凝胶隔热材料提供了新思路.

航天运载器磁悬浮助推发射关键技术

以航天运输为背景,研究了磁悬浮助推发射的磁悬浮、直线电机、空气动力影响和运载器分离发射等关键技术问题.通过磁悬浮系统比较,确定高温超导体EDS(E lectro-dynam ic Suspension)系统是适合的磁悬浮技术方案,在单元静、动态实验测试基础上,研究其基本静态悬浮导向性能和刚度、阻尼特性,并建立缩比研究试验平台以评估磁悬浮系统的综合性能.通过分析2种直线电机类型及优缺点,确定双边感应直线电机是适合磁悬浮发射系统的一种直线电机加速方式,并确定脉冲磁流体发电的能量供给方案.通过磁悬浮发射空气动力影响分析,优化设计磁悬浮发射装置气动外形和气动布局,得出其基本气动特性,并提出利于实现系统俯仰力矩平衡的气动翼控制方案.研究了运载器同时滑离导轨式定向器分离发射方案,并通过动静法计算分析得出运载器从定向器滑轨上成功分离所需具备的基本动力学参数.

基于反作用发动机推力的空天飞行器再入姿态飞行控制

研究了空天飞行器(ASV)再入跨大气层飞行时的姿态控制问题。在ASV跨大气层再入飞行时,通过反作用控制系统(RCS)中的反作用发动机推力产生控制力矩来控制ASV的姿态,以补偿气动舵面操纵失效或者部分失效而引起的控制力矩不足;随着空气密度的增加,气动舵面逐步介入控制系统,RCS随之逐步退出.由于快回路控制器产生进行姿态控制所需要的控制力矩,其通过相应的控制分配将控制力矩映射到作动器,为了减轻作动器的抖振,提出了利用基于区域模型的T-S模糊多模型控制方法设计快回路控制器,在跟踪期望角速度的同时,柔化控制信号.最后通过仿真验证了所提方法的有效性.

组合动力空天飞行器关键技术

针对组合动力系统的工作特征和空天飞行器的任务特点,总结组合动力空天飞行器面临的主要问题,并梳理了该类飞行器存在的主要关键技术。从气动布局、机体/推进一体化、热防护/热管理、制导、控制、地面和飞行试验等方面,详细阐述各类关键技术存在的难点,总结各类技术的发展现状,并分析给出未来可能的发展途径和方向。相关研究可指导未来组合动力空天飞行器的技术攻关。