<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005">
<channel xmlns:cfi="http://www.microsoft.com/schemas/rss/core/2005/internal" cfi:lastdownloaderror="None">
<title cf:type="text"><![CDATA[Editorial department of the Journal of National University of Defense Technology -->航天工程·机械工程]]></title>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Three-dimensional localization for moving target using modified Sage-Husa adaptive filter]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302017]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[A three-dimensional intersection localization method for moving target using two vision-based UAVs (unmanned aerial vehicles), which did not rely on the distance information from the target point to the UAV was proposed. An interacting multiple model estimator was adopted to the localization method to solve the problem of not knowing the motion form of the moving target. A modified Sage-Husa adaptive filtering algorithm that synthesized the covariance matching technique and the positive definiteness judgment was used to improve the accuracy of localization. To assess the performance of these approaches, a set of simulations that carried out under realistic conditions were presented. Results show that the method proposed can get the accurate three-dimensional coordinates of the target. The modified Sage-Husa adaptive filtering algorithm can improve the localization accuracy significantly, with the average estimation error reduced from 27.13 m to 14.62 m under the intersection angle of 90°. The influence of the intersection angle on localization was studied in the simulation, which shows that too small intersection angle is not conductive to the improvement of localization accuracy, a larger intersection angle is good for the localization method without filtering, but the effect on the method with the modified Sage-Husa adaptive filtering algorithm is not significant.]]></description>
<pubDate>2023/4/3 10:03:38</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[WU Anping, LU Yafei, GUO Zheng, HOU Zhongxi]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WU Anping, LU Yafei, GUO Zheng, HOU Zhongxi</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302017]]></guid><cfi:id>8</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis of the influence of rocket exit area in RBCC engine under the ejector mode]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302018]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to improve the performance of the rocket-based combined-cycle engine, the influence of the rocket exit area under the ejector mode was studied. Through numerical simulation research, the mass flow of captured air was mainly affected by the entrainment performance under the condition of low flight Mach number. The larger the rocket exit area, the better the entrainment performance. However, with the increase of flight Mach number, the kinetic energy of the entrainment air increases, and there is flow choking in the isolator. The mass flow of captured air was mainly limited by the geometric size of the isolator, independent of the rocket exit area. Under subsonic conditions, the smaller the rocket exit area is, the lower the specific impulse of the engine is, and when the exit dimensionless area is 3.15, the rocket plume will expand and impact the wall, which can cause a sudden reduction in performance. Under supersonic conditions, the smaller the rocket exit area, the higher pressure in the combustor, and the better performance of the rocket-based combined cycle engine.]]></description>
<pubDate>2023/4/3 10:03:38</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[YAO Yizhi, SUN Mingbo, HUANG Yuhui, LI Peibo, AN Bin, GU Rui, WANG Jiaoru, LI Menglei, WANG Taiyu, CHEN Jikai]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YAO Yizhi, SUN Mingbo, HUANG Yuhui, LI Peibo, AN Bin, GU Rui, WANG Jiaoru, LI Menglei, WANG Taiyu, CHEN Jikai</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302018]]></guid><cfi:id>7</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Regional coverage satellite constellation optimization algorithm fused with genetic ant colony algorithm]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302019]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to optimize the design of satellite constellations with specific area coverage and intensive revisits, a design scheme of regression orbit and co-subsatellite point trajectory constellation was adopted, and a method to optimally solve the satellite constellation orbit parameters by integrating genetic ant colony algorithm with the weight ranking coverage of key areas in specific area was proposed. The design requirements of the regional coverage constellation were analyzed, a regression orbit coverage area model was established, the optimal orbit root number was calculated by using the genetic ant colony algorithm, and all the constellation parameters were solved through using the co-subsatellite point trajectory constellation solution algorithm. The simulation results show that the optimized constellation meets the coverage time and revisit frequency requirements for the area target, and provides focused coverage and revisits of important locations in order of weight, which verifies the feasibility of the algorithm.]]></description>
<pubDate>2023/4/3 0:00:00</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[HUA Bing, WANG Peiyuan, WU Yunhua, CHEN Zhiming]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>HUA Bing, WANG Peiyuan, WU Yunhua, CHEN Zhiming</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302019]]></guid><cfi:id>6</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis of the difference between probability distribution of conditional aloft wind speed and normal distribution]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302020]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[As an important uncertainty factor in multidisciplinary optimization design of aerocraft, the statistical characteristics of aloft wind should be acquired accurately. The probability distribution of conditional aloft wind speed is unique, in order to facilitate the use of probability model of aloft wind for uncertainty design and reduce the amount of calculation, an analysis method of difference between probability distribution of conditional aloft wind speed and normal distribution was proposed, and the applicable condition for simplifying the distribution of probability distribution of conditional aloft wind speed to normal distribution was given. Numerical simulation results show that within latitude range of 24.3°N～42.2°N, the difference between condition aloft wind speed probability density and normal distribution probability density in different regions is trumpet-shaped in the range of 2～30 km above sea level, and the conditional aloft wind speed probability density is closest to that of normal distribution nearby the altitude of 15 km, which can be approximately assumed to be normally distributed. Based on the above work, suggestions were given for selecting the method of generating random samples when considering the uncertainty of the conditional aloft wind speed in the uncertainty design of aerocraft.]]></description>
<pubDate>2023/4/3 10:03:38</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[WANG Le, CHANG Hanjiang, CAI Yipeng]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WANG Le, CHANG Hanjiang, CAI Yipeng</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302020]]></guid><cfi:id>5</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Deterministic scheduling method with low latency for SpaceFibre]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302021]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to achieve the deterministic transmission of diverse data streams in a short time on the SpaceFibre network, the fine-grained low-latency deterministic scheduling algorithm with classification was proposed. According to the differentiated scheduling strategy, space tasks were divided into three types. For the efficient allocation of resources, the extended time-slot was introduced. The uniform distribution of time-slot without conflict reduced the average delay of data packets. To adapt to aerospace applications where payloads were connected with a network, the method generated scheduling vectors based on the network topology. The simulation model of the SpaceFibre network in OPNET was built to verify the effectiveness of the method. Experimental results show that the scheduling scheme generated by the method has better certainty than the classic scheduling based on priority and conflict-free consecutive scheduling; with the increment of the number of time slots, the average delay and jitter of each traffic are reduced, and the throughput is guaranteed. Therefore, the method has certain practical application value in aerospace engineering.]]></description>
<pubDate>2023/4/3 0:00:00</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[ZHENG Jingya, AN Junshe]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHENG Jingya, AN Junshe</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302021]]></guid><cfi:id>4</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Gas distribution system design for annular connecting straight cylinder engine]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302022]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The annular connecting straight cylinder engine has many advantages such as high power density, low inertia force and so on. However, the cylinder rotors always rotate along the circumferential direction of the output shaft during operation, which makes the traditional static gas distribution method no longer applicable. Therefore, it is of great significance to research and design a new type of gas distribution system that meets the intake and exhaust requirements of this type of engine. In view of the unique annular connecting structure and differential velocity motion characteristic of the engine, the volume change law of each rotor cylinder was analyzed, and the relationship between the intake and exhaust phases of each rotor cylinder and the rotor rotation angle was studied. On this basis, an innovative dynamic position gas distribution system with airway reuse feature was designed. According to the gas distribution scheme of two-stroke engine, the parts of the gas distribution system were designed and processed, and the dynamic intake and exhaust process was completed through high-pressure pneumatic test. The experimental results show that the engine can run stably at 200 r/min when the driving air pressure is 0.25 MPa, which effectively verifies the feasibility of the gas distribution system.]]></description>
<pubDate>2023/4/3 0:00:00</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[XU Haijun, YANG Congnan, XU Xiaojun, TANG Yuanjiang]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>XU Haijun, YANG Congnan, XU Xiaojun, TANG Yuanjiang</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302022]]></guid><cfi:id>3</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Ballistic performance of double-arrow negative Poisson′s ratio structure]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302023]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The penetration performance of the double-arrow negative Poisson′s ratio multicellular structure against bullet penetration was studied by numerical simulation method.The penetration behaviors of bullets and the damage forms of the double-arrow negative Poisson′s ratio structure under the three bullet target conditions of top-edge impact,hinge-point impact and side-impact were compared and analyzed.The results show that the negative Poisson′s ratio effect of the double-arrow negative Poisson′s ratio structure is not significant when the bullet impacts the structure at a high velocity.The bullet directly penetrates the structure at topside impact and hinge point impact,the damage of the cell element is small and the anti-intrusion performance of the double-arrow negative Poisson′s ratio multi-cell structure is poor at this time.The bullet does not penetrate the multi-cell structure at side impact,and the damage of the cell element is large;the double-arrow negative Poisson′s ratio structure relies on its double-Poisson′s ratio structure to deflect the bullet at side impact.The double-arrow negative Poisson′s ratio structure relies on its double triangular structure to deflect and roll the bullet during side impact,which significantly increases its penetration resistance.The effect of the change in the angle of incidence of the bullet during topside impact on the intrusion resistance of the double-arrow negative Poisson′s ratio structure was analyzed. It is found that there is a 30° angle of incidence and a 60° angle of incidence.The double-arrow negative Poisson′s ratio multi-cell structure has some resistance to penetration when the bullet is near these two incidence angles.]]></description>
<pubDate>2023/4/3 0:00:00</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[LIU Yangzuo, MA Dawei, REN Jie, ZHONG Jianlin, ZHAO Changfang]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LIU Yangzuo, MA Dawei, REN Jie, ZHONG Jianlin, ZHAO Changfang</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302023]]></guid><cfi:id>2</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Isodamage curves characterization methods of anti-damage capability for multi-axle special vehicle tire system]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302024]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to explore the survival probability of multi-axle special vehicle tire system under battlefield threat and quantitatively characterize the anti-damage capability of tire system, a new method based on isodamage curves was proposed to characterize the battlefield anti-damage capability of the tire system. Aiming at the influence of tire damage on the whole vehicle, the mechanical characteristics of tire system were quantitatively characterized based on vehicle dynamics, and the calculation model of tire system functional damage was established. Based on the damage theory, the collision and quantitative analysis of shock wave overpressure field were carried out, and the calculation model of tire system physical damage was established. According to the position relationship between the burst core and the vehicle, the calculation model of the tire system isometric line was established by using the characteristic line for the vehicle in the whole area. A five-axle special vehicle was taken as an example to verify the characterization method. Results show that this characterization method can be applied to the characterization of the anti-damage capability of the multi-axle special vehicle tire system under battlefield threat, which lays a model foundation for the improvement of maneuvering avoidance and protection ability in the future.]]></description>
<pubDate>2023/4/3 0:00:00</pubDate>
<category><![CDATA[航天工程·机械工程]]></category>
<author><![CDATA[HUANG Tong, GAO Qinhe, LIU Zhihao, WANG Dong, MA Dong, ZHU Jiaxuan]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>HUANG Tong, GAO Qinhe, LIU Zhihao, WANG Dong, MA Dong, ZHU Jiaxuan</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202302024]]></guid><cfi:id>1</cfi:id><cfi:read>true</cfi:read></item>
</channel>
</rss>