适合航天电子系统应用的DC－DC变换器

讨论了航天ＤＣ－ＤＣ混合集成电路的拓朴结构。通过对几种电路的性能比较，提出了适合航天应用的ＤＣ－ＤＣ变换器的最佳拓朴结构。论述了ＰＷＭ－ＬＩＮ变换器的控制方法，该方法对于确保二次稳压ＤＣ－ＤＣ变换器较高的效率具有重要意义，亦可大大提高混合集成电路的成品率。     

光纤传感器进展

重点描述了医学和航空工业中的几种光纤传感器,以及气体和温度分布传感器的目前状况。     

Making costly manufacturing smart with transfer learning under limited data: A case study on composites autoclave processing

The integration of advanced manufacturing processes with ground-breaking Artificial Intelligence methods continue to provide unprecedented opportunities towards modern cyber-physical manufacturing processes, known as smart manufacturing or Industry 4.0. However, the “smartness” level of such approaches closely depends on the degree to which the implemented predictive models can handle uncertainties and production data shifts in the factory over time. In the case of change in a manufacturing process configuration with no sufficient new data, conventional Machine Learning (ML) models often tend to perform poorly. In this article, a transfer learning (TL) framework is proposed to tackle the aforementioned issue in modeling smart manufacturing. Namely, the proposed TL framework is able to adapt to probable shifts in the production process design and deliver accurate predictions without the need to re-train the model. Armed with sequential unfreezing and early stopping methods, the model demonstrated the ability to avoid catastrophic forgetting in the presence of severely limited data. Through the exemplified industry-focused case study on autoclave composite processing, the model yielded a drastic (88%) improvement in the generalization accuracy compared to the conventional learning, while reducing the computational and temporal cost by 56%.     

Coverage path planning for eddy current inspection on complex aeronautical parts

Non-destructive testing (NDT) plays a critical role in controlling the structural integrity (therefore the quality) of aeronautical parts, during fabrication as well as during maintenance. Eddy current (EC) testing is one of the most used NDT techniques in the aerospace industry. However, EC testing is still mainly performed by human operators and reliability as well as repeatability is not always guaranteed. To solve these issues, automating this NDT technique with a robotic system is investigated. In this paper, an EC probe equipped with a passive compliant system is assumed to be attached to the end-effector of a 6-DOF manipulator arm to carry on the inspection. Then, assuming that a 3D model of the inspected part is known a priori, a coverage path planning method using a zigzag (or rastering) pattern adapted to EC testing on aeronautical structures with a complex geometry is proposed. To reach this objective, the approach adopted in this work is to adapt existing coverage path planning techniques based on a “divide-and-conquer” strategy used for spraying applications to EC inspection. More precisely, three successive segmentations are applied to the surface to be inspected so that consistent rastering paths can be generated. Simulation results are shown for a complex part of an aeronautical structure to demonstrate the efficiency of the proposed method.     

Additive manufacturing in the spare parts supply chain

As additive manufacturing (AM) evolves to become a common method of producing final parts, further study of this computer integrated technology is necessary. The purpose of this research is to evaluate the potential impact of additive manufacturing improvements on the configuration of spare parts supply chains. This goal has been accomplished through scenario modeling of a real-life spare parts supply chain in the aeronautics industry. The spare parts supply chain of the F-18 Super Hornet fighter jet was selected as the case study because the air-cooling ducts of the environmental control system are produced using AM technology. In total, four scenarios are investigated that vary the supply chain configurations and additive manufacturing machine specifications. The reference scenario is based on the spare parts supplier's current practice and the possible future decentralization of production and likely improvements in AM technology. Total operating cost, including downtime cost, is used to compare the scenarios. We found that using current AM technology, centralized production is clearly the preferable supply chain configuration in the case example. However, distributed spare parts production becomes practical as AM machines become less capital intensive, more autonomous and offer shorter production cycles. This investigation provides guidance for the development of additive manufacturing machines and their possible deployment in spare parts supply chains. This study contributes to the emerging literature on AM deployment in supply chains with a real-world case setting and scenario model illustrating the cost trade-offs and critical requirements for technology development.     

军民融合产业化的对策建议——以航天航空制造业为例

科学、协调发展国防建设与经济建设要求我们站在国家安全和发展战略全局的高度走出中国特色军民融合发展的新路子。我国的军民融合虽然有所发展但其规模、范围离产业化还相距甚远,论文以航天航空业为例就如何加速促进军民融合产业化从政府、军工企业、民用企业三个层面提出较全面的对策及建议。     

铸造CAE技术在航天产品上的应用及发展前景

铸件的凝固过程是一个复杂的高温、动态、瞬时的变化过程,在这个过程中缩孔、疏松等铸造缺陷会相继出现。利用铸造CAE技术可以在生产前发现这些缺陷的具体位置和大小,将质量隐患消灭在计算机模拟的反复比较优化中;并可有效地控制生产成本,提高铸件质量,使铸件获得很高的性价比。通过介绍铸造CAE技术在推动传统铸造向现代铸造发展中发挥的重要作用,以及在北京航星机器制造公司及其它相关企业中的应用情况,阐述了铸造CAE技术在航天产品铸造生产中广阔的应用前景。     

航空涡轮发动机失稳预警信号提取方法的研究

综合航空涡轮发动机失稳先兆波的幅值特性与频率特性,设计出能够提取失稳先兆特征的处理方法,并据此对发动机失稳数据进行处理与分析。通过使用不同的参数,此方法可实现对模态波和尖脉冲型失稳的预警。处理结果表明,此提取方法能够在失稳前15～20个转子周期内,有效地对尖脉冲型失稳进行预报,对模态波型失稳能够在60～80个转子周期前预警。并且此提取方法的算法复杂度较低,有利于失稳的在线预警,对航空燃气涡轮发动机主动控制技术的发展具有十分重要的意义。     

Aircraft design optimization

In this paper we describe briefly a set of procedures for the optimal design of full mission aerospace systems. This involves multi-physics simulations at various fidelity levels, surrogates, distributed computing and multi-objective optimization. Low-fidelity analysis is used to populate a database of inputs and outputs of the system simulation and Neural Networks are then designed to generate inexpensive surrogates. Higher fidelity is used only where is warranted and also to do a local exploration after global optimization techniques have been used on the surrogates in order to provide plausible initial values. The ideas are exemplified on a generic supersonic aircraft configuration, where one of the main goals is to reduce the ground sonic boom.