空间红外遥感器定标机构故障应急退出装置

针对空间红外遥感器定标机构故障模式,首次设计了一种基于记忆合金的应急退出装置,以解决因电机或控制电路故障而导致的整个成像系统失效问题。该应急退出装置通过对记忆合金棒进行加热,使其受热收缩,从而驱动齿轮传动系统脱离啮合状态,完成机构复位运动。为验证该应急退出装置的功能和性能,利用研制产品进行了真空、大气环境等多种状态下的应急退出试验。结果表明:在大气和真空环境中,该装置能实现多种状态下的可靠退出功能;在28 V额定直流工作电压下,应急退出总时间可达145～152 s。该机构具有实现简便、可靠性高、退出速度快等优点,在空间机构的故障应急方面具有较大的工程应用潜力。     

Exploring mission planning method for a team of carrier aircraft launching

High-level efficiency and safety are of great significance for improving the fighting capability of an aircraft carrier. One way to enhance efficiency and safety level is to organize the carrier aircraft into combat effectively. This paper studies the mission planning problem for a team of carrier aircraft launching, and a novel distributed mission planning architecture is proposed. The architecture is hierarchical and is comprised of four levels, namely, the input level, the coordination level,the path planning level and the execution level. Realistic constraints in each level of the distributed architecture, such as the vortex flow effect, the crowd effect and the motion of aircraft, are considered in the model. To solve this problem, a distributed path planning algorithm based on the asynchronous planning strategy is developed. The proposed Mission Planning Approach for Carrier Aircraft Launching(MPACAL) is validated using the setups of the Nimitz-class aircraft carrier.Compared to the isolated planning architecture and the centralized planning architecture, the proposed distributed planning architecture has advantages in coordinating the launch tasks not only belonging to the same catapult but also when all different catapults are considered. The proposed MPACAL provides a modeling method for the flight deck operation on aircraft carrier.     

基于滚动时域的舰载机甲板运动轨迹跟踪最优控制

针对单机滑行、无杆牵引系统以及有杆牵引系统的轨迹跟踪问题进行了研究。首先，将这3种系统的轨迹跟踪问题转化为最优控制问题，并建立了连续非线性舰载机系统的轨迹跟踪模型。然后，基于第3类生成函数，提出了适用范围更广的全状态保辛伪谱算法，并结合滚动时域理论提出了基于滚动时域（RHC）的在线跟踪最优控制方法，证明了所提算法是一种保辛算法。基于所提出的在线跟踪算法，对单机滑行、无杆牵引系统、有杆牵引系统在存在初始偏差和持续外界扰动情况下的轨迹跟踪问题分别进行了研究，并与BackwardSweep方法进行对比分析，结果表明本文所提出的跟踪算法可以有效地解决具有控制约束和状态约束的轨迹跟踪问题，并可以更高的跟踪精度和计算效率对标准轨迹进行跟踪，可完全满足实时跟踪的要求。最后，分别从初始偏差和持续外界扰动的角度研究了这3种不同方式的跟踪特性。     

Load balancing strategy and its lookup-table enhancement in deterministic space delay/disruption tolerant networks

Space networks, in which connectivity is deterministic and intermittent, can be modeled by delay/disruption tolerant networks. In space delay/disruption tolerant networks, a packet is usually transmitted from the source node to the destination node indirectly via a series of relay nodes. If anyone of the nodes in the path becomes congested, the packet will be dropped due to buffer overflow. One of the main reasons behind congestion is the unbalanced network traffic distribution. We propose a load balancing strategy which takes the congestion status of both the local node and relay nodes into account. The congestion status, together with the end-to-end delay, is used in the routing selection. A lookup-table enhancement is also proposed. The off-line computation and the on-line adjustment are combined together to make a more precise estimate of the end-to-end delay while at the same time reducing the onboard computation. Simulation results show that the proposed strategy helps to distribute network traffic more evenly and therefore reduces the packet drop ratio. In addition, the average delay is also decreased in most cases. The lookup-table enhancement provides a compromise between the need for better communication performance and the desire for less onboard computation.     

Four-axis trochoidal toolpath planning for rough milling of aero-engine blisks

The Blade Integrated Disk (Blisk) is one of the key components in the aero-engine, it is generally manufactured by the multi-axis milling and almost 90% raw materials are removed. To avoid the full immersion of a cutter in the rough machining of a blisk channel, the trochoidal milling is a promising strategy since it can keep a small immersion angle in the rough milling process while maintaining the high machining efficiency. However, while toolpaths are being planned for the trochoidal milling process, the conventional methods are mainly for the planar machining area with fixed tool orientations, which cannot be used for complex channels where the multi-axis machining should be employed. To this end, this paper presents a four-axis trochoidal toolpath planning method with a ball-end cutter, and thus the blisk channel can be machined efficiently. For this to happen, the trochoidal paths are planned in the parametric domain and then mapped into the physical domain, with tool orientations controlled by the quaternion interpolation method to have smooth tool movement along the toolpaths. Both geometric simulation and physical milling experiments of the proposed method have convincingly demonstrated the validation of the proposed method.     

大型水陆两栖飞机抗浪能力研究

阐述了大型灭火/水上救援水陆两栖飞机高抗浪船体设计方法，对飞机起飞过程中的水阻力、滑行稳定性和波浪运动响应进行了研究。通过对比分析，发现断阶喷溅形态是影响水阻力出现第2峰值的关键因素，提出了水阻力曲线出现第2峰值的条件；分析了在纵倾角-速度图中不同区域滑行时飞机纵倾角响应特性，明确了飞机在典型状态的稳定边界；通过研究波长、速度对飞机纵倾角、飞高和机身垂向过载的影响，确定了飞机在波浪水面发生剧烈运动响应时对应的波长范围。     

基于不规则障碍物环境下无人机的改进几何路径规划算法

随着无人机应用环境的多样化,在复杂环境中寻找无碰撞路径是非常重要的。传统的路径规划算法可以找到可行的路径,但它们在时间效率和路径长度之间没有很好的平衡,传统的几何算法只能避免特殊形状的障碍物。提出了一种改进的几何路径规划算法,使无人机能够在复杂的环境中避开任意形状的障碍物,找到较短的路径。首先,针对不规则障碍物,建立了凸多边形覆盖模型。然后解决了传统几何算法陷入局部最优解的缺点。提出了从相邻路径段生成无碰撞路径的二次规划思想,并针对该方法提出了一种新的安全阀值策略。最后,为了验证算法的性能,在不同的复杂环境下进行了仿真,并从几个方面对所提出的算法与A*算法进行了对比分析。     

变速恒频电源控制器的设计与实现

首先对变速恒频电源控制器（ＧＣＣＵ）的控制功能，保护功能，ＢＩＴ功能进行了详细分析，重点讨论了ＢＩＴ功能和ＧＣＣＵ的硬件设计方案。采用８０９７ＢＨ单片微型计算机，使硬件结构大大简化。文中还对电源系统的故障模式进行了较详细的分析，并阐述了ＧＣＣＵ软件设计的主要技术问题，提出了若干软件设计原则，给出了主要软件框图。所设计的ＧＣＣＵ在变速恒频电源系统中获得了满意的应用     

发动机指示和机组警告系统的监控研究

本文作者在详细研究发动机指示和机组警告系统的基础上，对其监控技术和原理作了较为深入的探讨。这对了解其他的机载电气、电子设备的监控及测试技术也会有所帮助。