Autonomous Control Reconfiguration of Aerospace Vehicle Based on Control Effectiveness Estimation

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.

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.

Path-Following Control With Obstacle Avoidance of Autonomous Surface Vehicles Subject to Actuator Faults

This paper investigates the path-following control problem with obstacle avoidance of autonomous surface vehicles in the presence of actuator faults,uncertainty and external disturbances.Autonomous surface vehicles inevitably suffer from actuator faults in complex sea environments,which may cause existing obstacle avoidance strategies to fail.To reduce the influence of actuator faults,an improved artificial potential function is constructed by introducing the lower bound of actuator efficiency factors.The nonlinear state observer,which only depends on measurable position information of the autonomous surface vehicle,is used to address uncertainties and external disturbances.By using a backstepping technique and adaptive mechanism,a path-following control strategy with obstacle avoidance and fault tolerance is designed which can ensure that the tracking errors converge to a small neighborhood of zero.Compared with existing results,the proposed control strategy has the capability of obstacle avoidance and fault tolerance simultaneously.Finally,the comparison results through simulations are given to verify the effectiveness of the proposed method.

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.

Cooperative Target Tracking of Multiple Autonomous Surface Vehicles Under Switching Interaction Topologies

This paper is concerned with the cooperative target tracking of multiple autonomous surface vehicles(ASVs)under switching interaction topologies.For the target to be tracked,only its position can be measured/received by some of the ASVs,and its velocity is unavailable to all the ASVs.A distributed extended state observer taking into consideration switching topologies is designed to integrally estimate unknown target dynamics and neighboring ASVs'dynamics.Accordingly,a novel kinematic controller is designed,which takes full advantage of known information and avoids the approximation of some virtual control vectors.Moreover,a disturbance observer is presented to estimate unknown time-varying environmental disturbance.Furthermore,a distributed dynamic controller is designed to regulate the involved ASVs to cooperatively track the target.It enables each ASV to adjust its forces and moments according to the received information from its neighbors.The effectiveness of the derived results is demonstrated through cooperative target tracking performance analysis for a tracking system composed of five interacting ASVs.

A novel three-inflection-point sliding mode control framework for forward-tilting morphing aerospace vehicle with performance constraints and actuator faults

A prescribed performance control scheme based on the three-inflection-point hyperbolic function and predefined time performance function is proposed to solve the trajectory tracking problem of the forward-tilting morphing aerospace vehicle with time-varying actuator faults.To accurately estimate the loss degree of actuator faults,an immersion and invariance observer based on the predefined time dynamic scale factor is designed to estimate and compensate it.A composite dynamic sliding mode surface is designed using a three-inflection-point hyperbolic function,and a novel three-inflection-point sliding mode control framework is proposed.The convergent domain of the sliding manifold is adjusted by parameters,and the system error convergence is controllable.A transfer function is designed to eliminate the sensitivity of the three-inflection-point hyperbolic sliding mode to the unknown initial state,and combined with the barrier Lyapunov function,and the performance constraint of the system is realized.The global asymptotic stability of the system is demonstrated using a strict mathematical proof.The effectiveness and superiority of the proposed control scheme are proven by simulation experiments.

面向海上搜救的ASV与AUV的协同控制

针对采用由自主水面船和自主水下航行器组成的异构海洋航行器集群进行协同搜救的问题,采用大地坐标系和船体坐标系建立自主水面船和自主水下航行器的运动学模型;基于视距制导策略,引入流体坐标系,设计适用于自主水面船和自主水下航行器的三维异构协同路径跟踪控制器,实现协同搜救;基于李雅普诺夫稳定性原理证明闭环系统的稳定性。仿真结果表明,提出的面向海洋搜救的三维异构协同路径跟踪控制器是有效的。

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。

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。

面向控制的变构型空天飞行器建模及特性分析

针对空天飞行器爬升过程中,传统固定构型难以兼顾高低速气动性能的问题,提出了一种空天飞行器变构型调节策略。首先,提出了一种翼面伸缩的变构型方式,构建了含有表征飞行器构型变量的气动代理模型;其次,基于气动代理模型对飞行器气动和配平特性进行分析,根据气动特性制定构型变化策略,根据配平特性提出质心位置匹配设计;然后,根据构型变量和爬升飞行平衡的约束,以控制输入最小为目标,优化得到了合适的质心位置,为不同构型的质心位置设计提供参考;最后,仿真结果表明变构型空天飞行器在爬升飞行任务中起到分担舵面负载和减小油门的作用,增加了飞行过程的稳定性。

高端航天器连接状态检测技术研究进展

航天飞行器向高性能发展是目前的主流需求,而连接状态退化是高端航天飞器高性能运行的“潜在威胁”,连接状态检测技术是保障航天器高性能运行的“监护保险”。综述了高端航天器连接状态检测技术的最新研究进展,旨在保障航天器的高性能运行与安全性。首先阐述了航天器连接状态检测的重要性,指出其作为确保航天飞行器高效运行的关键“保障措施”,接着从螺栓预紧力检测和接触界面状态检测两个方面,详细分析了国内外在该领域的研究现状与方法,揭示了高端航天器连接状态检测技术理论与方法所面对的挑战,并探讨了应对这些挑战的解决途径和发展趋势。为航天器连接状态检测技术的进一步发展提供了理论基础与实践指导。

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。

基于亚太6D通信卫星的天基测控技术研究

如今商业航天快速发展,传统测控资源难以满足商业火箭高密度快速发射的测控需求,尤其是针对航区海基测控资源紧缺,基于天链卫星的天基测控资源不适应未来商业航天发射模式。通过调研中国民商用通信卫星测控资源,研究了基于亚太6D通信卫星的Ku频段天基测控技术,结合通信卫星性能指标完成链路计算,提出天基测控系统箭载测控设备与地面测控设备实现方案,完成天基测控系统架构及信息流设计,为商业航天火箭发射提供新的测控实施方案,有效缓解测控资源紧张难题,测控弧段可覆盖运载火箭典型SSO轨道测控需求。

航空航天飞行器零部件检测中三坐标测量机的应用研究

聚焦航空航天飞行器关键零部件检测的难题,深入研究了三坐标测量机在复杂曲面和精密孔系检测中的应用。针对大尺寸复杂曲面零部件,提出了基于接触式测头的点云测量策略,实现了曲面形貌的高精度重构;针对传感器安装支架等精密孔系零部件,提出了离散点测量方法,通过合理布点获得了关键参数的精确测量结果。结果表明,所提测量方法能实现航空航天飞行器关键零部件的高精度检测,为飞行器研制过程中的质量控制提供了关键的测量手段。

空天飞行器概念设计再入数学建模研究

研究了空天飞行器(ASV)再入飞行条件下6自由度数学建模问题,所建数学模型包含完整的6自由度动力学方程和运动方程。气动力和力矩系数是迎角、马赫数、高度及控制舵面偏角的函数,反作用控制系统(RCS)推进器属于开关型的,控制量可近似为常值开关型的量。开环特性分析说明整个模型能够体现出ASV复杂的非线性、耦合性以及快时变性等特点,可满足新一代高超声速飞行器轨迹优化、姿态控制等问题的概念设计和仿真研究。