考虑外包混合形式的TOC产品组合优化研究

 首先,根据外包的两种形式(带料外包、不带料外包)研究了外包混合形式下产品组合优化的建模问题,并通过数学证明其有效产出最优。其次,应用免疫算法(IA)对其进行了优化求解,在合理时间内得到大、小规模产品组合决策的最优解或近优解。最后,将本算法与传统TOCh、修订TOCh、整数规划(IP)、禁忌搜索(TS)、遗传算法(GA)等进行了仿真比较,证明了本算法的有效性和实用性。     

基于相频约束的航天器定时技术

双向相干测距测速体制是最常用的航天器测量体制,是一种闭环体制.与之相比较,开环测距测速可以在信号更微弱的情况下获取到观测量,在深空任务中有着独特的意义.然而,开环测距也面临棘手的技术难题——高精度航天器定时技术.针对该难题,在保持现有航天器信号体制的基础上,阐述了基于遥测信号和测距侧音信号（差分单向测距DOR信号可看作侧音信号）间相频约束的航天器定时原理,研究了侧音频率最优化设计方法,给出了“器上发射测站接收”的初步实现方案,为后续开展工程应用奠定了基础.     

Cooperative guidance strategy for multiple hypersonic gliding vehicles system

Cooperative guidance strategy for multiple hypersonic gliding vehicles system with flight constraints and cooperative constraints is investigated.This paper mainly cares about the coordination of the entry glide flight phase and driving-down phase.Different from the existing results,both the attack time and the attack angle constraints are considered simultaneously.Firstly, for the entry glide flight phase, a two-stage method is proposed to achieve the rapid cooperative trajectories planning, wh...     

Formation flight of fixed-wing UAV swarms: A group-based hierarchical approach

This paper investigates a formation control problem of fixed-wing Unmanned Aerial Vehicle (UAV) swarms. A group-based hierarchical architecture is established among the UAVs, which decomposes all the UAVs into several distinct and non-overlapping groups. In each group, the UAVs form hierarchies with one UAV selected as the group leader. All group leaders execute coordinated path following to cooperatively handle the mission process among different groups, and the remaining followers track their direct leaders to achieve the inner-group coordination. More specifically, for a group leader, a virtual target moving along its desired path is assigned for the UAV, and an updating law is proposed to coordinate all the group leaders’ virtual targets; for a follower UAV, the distributed leader-following formation control law is proposed to make the follower’s heading angle coincide with its direct leader, while keeping the desired relative position with respect to its direct leader. The proposed control law guarantees the globally asymptotic stability of the whole closed-loop swarm system under the control input constraints of fixed-wing UAVs. Theoretical proofs and numerical simulations are provided, which corroborate the effectiveness of the proposed method.     

Robust H∞ controller design for attitude stabilization of flexible spacecraft with input constraints

This paper addresses the attitude stabilization and vibration suppression problem for flexible spacecraft subject to model parameter uncertainty, controller perturbations, external disturbances and input constraints. The attitude model of flexible spacecraft is described and converted into a state space form in terms of passive and active vibration suppression schemes. A novel state feedback controller is proposed based on the exactly available expectation of a new variable, which is introduced to model a randomly occurring controller gain perturbation. Based on Lyapunov stability theory, sufficient conditions for the existence of the nonfragile H_∞ controller considering input constraints are given based on linear matrix inequalities (LMIs) in terms of additive perturbation and multiplicative perturbation. Then, the developed controller subject to required constraints can be obtained, where the nonfragile property is fully considered to improve the tolerance to uncertainties in the controller. Numerical simulations are performed to demonstrate the effectiveness and superiority of the proposed control strategy in attitude stabilization and vibration suppression, where it should be noted that the passive vibration suppression scheme is superior for high natural frequencies while the active vibration suppression scheme is superior for low natural frequencies. Moreover, the low natural frequencies have more influence on the performance of attitude stabilization and vibration suppression.     

A triangle voting algorithm based on double feature constraints for star sensors

A novel autonomous star identification algorithm is presented in this study. In the proposed algorithm, each sensor star constructs multi-triangle with its bright neighbor stars and obtains its candidates by triangle voting process, in which the triangle is considered as the basic voting element. In order to accelerate the speed of this algorithm and reduce the required memory for star database, feature extraction is carried out to reduce the dimension of triangles and each triangle is described by its base and height. During the identification period, the voting scheme based on double feature constraints is proposed to implement triangle voting. This scheme guarantees that only the catalog star satisfying two features can vote for the sensor star, which improves the robustness towards false stars. The simulation and real star image test demonstrate that compared with the other two algorithms, the proposed algorithm is more robust towards position noise, magnitude noise and false stars.     

多资源约束下航天多项目调度的启发式算法

为解决当前航天多型号并举研制现状下的资源约束多项目调度问题,首先建立了一个数学模型,然后根据模型的特点提出了一种启发式算法。建立的模型同时考虑多项目的总工期和各个单项目的总工期,提出的算法在考虑活动资源可剥夺以及单个活动需要多个资源的情况下,能够合理优化多项目的资源分配,缩短多项目的总工期及各项目工期。通过实例验证该方法能够有效地求解多项目调度问题,具有一定的工程应用价值。     

An improved neutron transport algorithm for HZETRN

Long-term human presence in space requires the inclusion of radiation constraints in mission planning and the design of shielding materials, structures and vehicles. It is necessary to expose the numerical tools commonly used in radiation analyses to extensive verification, validation and uncertainty quantification. In this paper, the numerical error associated with energy discretization in HZETRN is addressed. An inadequate numerical integration scheme in the transport algorithm is shown to produce large errors in the low energy portion of the neutron and light ion fluence spectra. It is further shown that the errors result from the narrow energy domain of the neutron elastic cross section spectral distributions and that an extremely fine energy grid is required to resolve the problem under the current formulation. Since adding a sufficient number of energy points will render the code computationally inefficient, we revisit the light ion and neutron transport theory developed for HZETRN and focus on neutron elastic interactions. Two numerical methods (average value and collocation) are developed to provide adequate resolution in the energy domain and more accurately resolve the neutron elastic interactions. An energy grid convergence study is conducted to demonstrate the improved stability of the new methods. Based on the results of the convergence study and the ease of implementation, the average value method with a 100 point energy grid is found to be suitable for future use in HZETRN.     

满足多终端约束的二次曲线迭代制导方法研究

某些空间载荷会对入轨精度和入轨姿态同时提出很高的要求,应用于运载火箭控制系统的摄动制导方法的入轨精度无法满足要求,而传统的迭代制导方法无法约束终端的入轨姿态。为此提出了一种满足多终端约束的二次曲线迭代制导方法,该方法通过二次曲线形式规划整个真空段的飞行制导程序角,实时满足位置、速度与终端姿态约束,从而可以使得火箭以期望姿态角实现高精度入轨。算例结果表明,该方法能同时保证高精度的入轨指标和入轨姿态,并能适应偏差状态、约束姿态角变化与轨道根数小幅变化,具有较高的工程应用价值。     

飞机颤振主动抑制控制律优化设计

对颤振主动抑制控制律的优化设计进行了研究，提出了一种基于“极点配置”思想，考虑低速稳定性的工程性控制律初值设置方法；在优化过程中，除考虑阵风响应等约束外，还考虑了鲁棒性问题。以某型收音机的动力相似模型为实例进行计算。计算结果表明，设计的优化控制律能有效抑制颤振，保证低速稳定性，且系统满足工程稳定裕度要求。