UAV的发展趋向

blackbird

好新课题：

原帖由 pfg1group 于 16-3-2006 08:34 AM 发表


这一个我就很奇怪. 除非离飞机场很近. 要不然一般UAV根本不可能飞行到民航机的高度的吧?  有时候外国人做东西就是这样, 老是很多规则.


MSC都还可以到BRISTOL出席国际会议? 你老板还蛮多钱的!
建议 ...

在航太界的 UAV 研究, 我老闆是很有名的. 台灣航太界有兩個 AIAA Fellow. 他是其中一個. 也是20年前在台灣第一個提出 UAV 的人, 不過那時候沒人管他. 在台灣航太界, 提起蕭飛賓教授, 應該沒人不認識. 也因為這樣, 他申請的計畫都會通過. 台灣 UAV 最好的計畫, 都被他拿走了... 不過, 他從來不動手做的... 辛苦的, 就是我們囉...

錢是有很多, 但是我老闆有三間實驗室, 一個是做 UAV 的(我的實驗室), 一個做 Aerodynamics & Fluid Dynamics, 一個做 Nanotech. 所以 funding 是互相 cover 的, 因為有時候一些實驗室沒有計畫. 就這樣, 我們的 salary 就很低囉... 不過, 買 equipment 的錢是沒問題啦.

說到去 Bristol... 其實實驗室有補助, 但是不多啦, 連機票都不夠. 我是想說機會難得, 所以自己再花一些錢去參加. 想不到就這樣... 被老闆抓去當 presenter... 就當作是經驗囉.

Journal 方面, 通常沒有 journal 是專門給 UAV 的. 我們做 paper survey 的時候, 都會看 AIAA, IEEE, Journal of Aircraft.

原帖由 pfg1group 于 17-3-2006 02:11 AM 发表


根据这个graph的意思, 那也就是说, 当一架定翼飞机起飞了以后, 它的表现就必须要靠它的速度来维持?

飞机的最佳控制性能表现要到最 ...

根據我的了解...

n 是 load factor, 而那個 curve 是針對每一個速度(V)的 maximum load factor. 所以, 速度越快, maximum load factor 越高.

n = L / W            ....Eq(1)
L =0.5*rho*V^2*CL*S   ....Eq(2)
n = load factor
L = lift force
W = weight (assumed constant)
rho = air density (constant at certain altitude)
V = velocity
CL = lift coefficient
S = wing area (constant)

所以 n_max increase by the square of V, 型成前半部的 curve. 過後, maximum load factor 不再增加, 是因為受限於飛機的 structure 沒辦法承受更高的 load factor.

Va 之所以被稱為 optimum speed 應該是因為在那個速度, 飛機的 working Angle of Attack (AOA) 的範圍是最大, 而且 n_max 也最大. 怎麼說呢?

CL = CL_alpha*alpha + CL_0   ....Eq(3)
CL_alpha = lift slope (constant)
alpha = Angle of Attack
CL_0 = zero lift coefficient (constant)

先不管什麼是 CL_0. 從 Eq(3) 可以看到, CL 是 linearly 隨著 AOA 改變的. 但是這個關係到了一個程度就不成立了. 如果 AOA 太大, CL 會下降, 飛機會 stall. 而最高的 CL 值, 就是 CL_max. 記著, CL 的改變是 AOA 造成的, 到了一定的 AOA, CL 會增加到 CL_max. 如果 AOA 再增加, 飛機就 stall 了. 也就是說每一台飛機都有一個 working AOA 的範圍.

在前面 curve 的部份, 因為 V 小 (refer Eq(2) & Eq(1)), 所以能到達的 n_max 並不 optimum. 在 Va, n_max 是 optimum 的. 前面這個部份的 working AOA 的範圍也是 optimum 的. 後面 n_max constant 的部份, 飛機的 working AOA 範圍越來越小, 因為在一定的 V, 增加 AOA --> 增加 CL --> 增加 L --> 增加n... 如果到了 n_max, AOA 再繼續增加的話, 飛機的結構承受不了, 就 structure failure 了. 從 Eq(1) 和 Eq(2) 來看, n 固定 --> L 固定, 所以 V 越大, CL 就越小了.   

講了一堆, 希望你能明白. 結論是一台飛機的表現, 在 Va 時, 是最好的. 當然, 不同的飛機, Va 也不同.

Positive stall curve... 其實, 上面的 curves 都叫 positive stall curve. Dotted line 那個是如果把 flap deploy 的話, positive stall curve 就移到那裡去. 我剛才講過, CL 的改變是 AOA 造成的, 到了一定的 AOA, CL 會增加到 CL_max. 如果 AOA 再增加, 飛機就 stall 了. 這就是 positive stall curve 的意思, 因為針對不同 V 的 n_max --> L_max --> CL_max --> AOA for CL_max. 在一定的 V, 到了 n_max, AOA 再增加的話, 飛機就 stall, 不可能有 n beyond n_max 的. 因為這樣, 那條 curve 叫做 positive stall curve.  

Design diving speed... 給我時間想. 想好了再補充.

近來很忙... 而且實驗一直不成功, 應該會一段時間不上來了.

原帖由 pfg1group 于 17-3-2006 02:17 AM 发表
原来, 当我们还在讨论UAV的时候, 我们已经落伍了.
美国人现在正在讨论着UCAV.

http://www.janes.com/aerospace/m ... idr040713_1_n.shtml



UAV - unmanned air vehicle, 无人 ...

UCAV, 其實已經好一段時間了. 只是除了 stealth, 還有什麼特別嗎? 我一直都在懷疑, 有什麼是 UCAV 做得到而 Predator 做不到的? 原本設計來做偵查的 Predator 都已經可以帶飛彈了, 那... UCAV 的定義又在哪裡?

就我看來... UAV --> UCAV, 換湯不換藥. 但是, 也樂見其成啦.

blackbird

关于 Diving speed, 也是 aircraft maximum speed，代表了maximum dynamic pressure , q.这是对解构设计很重要（structural sizing）。

在这情况下，飞机是以相当地小的 Angle of attack 因为 q 是很大，所以它的 load 是接近知垂直在物体轴线（body axis）.

pfg1group

原帖由 ahChan 于 18-3-2006 03:52 AM 发表


UCAV, 其實已經好一段時間了. 只是除了 stealth, 還有什麼特別嗎? 我一直都在懷疑, 有什麼是 UCAV 做得到而 Predator 做不到的? 原本設計來做偵查的 Predator 都已經可以帶飛彈了, 那... UCAV 的定義又在哪裡 ...

导弹要从挂架上面发射出去。 是另外一个学问来的。尤其是射控软体， 和雷达照明等等。
如果我没有记错的话， f-14用的凤凰空对空导弹也曾经尝试过挂在在F-18上。 耗费了两百万美元，依然不成功。

pfg1group

Lockheed Martin's Skunk Works is believed to be developing a high-altitude, stealthy unmanned aircraft system (UAS) for the US Air Force (USAF) under a secret programme, funded with money taken from the terminated Joint Unmanned Combat Air System (J-UCAS) project.

The existence of a classified air force UAS project was disclosed in a navy Fiscal Year 2007 budget document, which stated that the Pentagon "directed the J-UCAS programme to split into two separate programmes: one air force classified programme and a navy UCAV [unmanned combat aerial vehicle] programme".

The new UAV, sometimes known as the Penetrating High Altitude Endurance (PHAE), is believed to be capable of operating at the 70,000-80,000 ft altitudes used by the U-2. One report refers to the aircraft using engines from an inventory that has been in storage since the 1970s. This almost certainly refers to the General Electric J97-GE-3 engine for the Teledyne Ryan AQM-91 Compass Arrow UAV (a project terminated in 1971). In 1998, a NASA paper reported that 24 J97 engines were in storage at the agency's Ames research centre. The Compass Arrow exceeded 80,000 ft during tests, the highest unclassified altitude ever recorded for a subsonic jet-powered aircraft. The J97 was rated at around 25 kN and the new UAV is probably a twin-engine design.

The new UAV is much larger than the small stealth UAV that has been evaluated operationally in Iraq. That aircraft - believed to be powered by one or two Williams FJ33 engines - has only eight hours' endurance, like DarkStar, and that is currently seen as inadequate.

http://www.janes.com/aerospace/m ... idr060321_1_n.shtml

pfg1group

对不起，上一楼的英语我忘记翻译。
等一下回来翻译给大家

alaves23

好恐怖
完全插不進去

各位大大的水準真是驚人！

Cod_XIII

现在美军已经把UAV称为UAS Unmanned Aircraft System了。现代UAV的概念来自导弹和RPV，并且它还具有更深的含义。

对于UAV，它的飞行和任务执行是自动的，而一些关键的决策，像目标确定、武器的释放、损伤评估、任务的继续或终止、不同目标的选择以及任务的更改，则由遥控飞行员来完成，这种设计思想在UAV,UTA和UCAV中得到了很好的体现。

携带武器并可反复使用的无人战斗机才是真正意义上的UCAV,它的杀伤能力是另外携带的武器而不是自己本身。美国海军的X-47 Pegasus 算是第一款使用RTOS的UCAV.

Craven83

今天将此帖列入精华，希望今后论坛能够有更多类似这样纯学术性的交流

剛從歐洲回來. 去 Bristol 參加了一個 UAV Conference. 發現大家所面對的問題有以下幾種:

(1) Regulation 法規
(2) Spectrum 溝通頻率
(3) Reliability 可靠度

好像還有一些, 等我拿到 Conference 的 CD 再補充一下.

pfg1group

原帖由 ahChan 于 12-4-2006 05:01 AM 发表
剛從歐洲回來. 去 Bristol 參加了一個 UAV Conference. 發現大家所面對的問題有以下幾種:

(1) Regulation 法規
(2) Spectrum 溝通頻率
(3) Reliability 可靠度

好像還有一些, 等我拿到 Conference 的 CD  ...

老实说, 如果你说control不是问题, 我会感觉到很惊奇.

blackbird

纳吉：我国制造供武装部队使用　无人驾驶飞机3个月内测试
2006-4-13 23:34:13

（万挠13日讯）副首相拿督斯里纳吉周四表示，我国制造的无人驾驶飞机（UAV）预料将在未来3个月内完成，并进行测试工作。

他在此间主持大马防御工业理事会会议，并参观引擎科技工业私人有限公司（MTI）后对记者说：“如果上述无人驾驶飞机的表现如摄影机及其他机件都符合规格，我们将会订购由本地制造的无人驾驶飞机供大马武装部队使用。”

也是国防部长的纳吉指出，有关单位已准备了足够的资金，以供大马武装部队购买无人驾驶飞机。

最初，共有3家公司作出竞争并建造各自的无人驾驶飞机。但大马防御工业理事会经过商议后，决定让3家公司合作生产。

他说：“作出决定后，上述3家公司已合并。我们将在未来3个月看到我国生产的第一架无人驾驶飞机。”
http://chinese.cari.com.my/news/ ... 6413_41924&rt=N
=================================================================

ah chan, 不懂我们的学校有份吗？
据说在LIMA'05 CTRM的 UAV 在当天试飞不成，只有我们 USM 的成功全程autonomous起飞及降落但他蛮重 35kg....
我有它的video clip讲述它的背景，从bak endri 的红色UAV 到 illylia 的黄色的 mosquito UAV。如有兴趣可向我讨！

steven268h

原帖由 blackbird 于 14-4-2006 01:05 AM 发表
纳吉：我国制造供武装部队使用　无人驾驶飞机3个月内测试
2006-4-13 23:34:13

（万挠13日讯）副首相拿督斯里纳吉周四表示，我国制造的无人驾驶飞机（UAV）预料将在未来3个月内完成，并进行 ...

我要~ 你给我看看那个video clip~

blackbird

原帖由 steven268h 于 14-4-2006 09:54 AM 发表


我要~ 你给我看看那个video clip~

不好意思，最近忙考试（明天是第一张）
那个file 有40++Mb，我怎样send 给你呢？

不好意思, 在趕論文, 都沒時間上來. 而且老闆去了美國, conference 的 CD 還沒拿到, 沒辦法詳細回答.

Control 的問題是包含在 Reliability 裡面的. 用哪一種 control law, 怎麼設計 controller 才會 reliable, 那絕對是一個大家面對的問題. 當然, reliability 涵蓋範圍很廣. 終極目標是要做到 plug & play 的程度, 插上電源, 就去飛, 而且一定會完成目標(不可能100%啦, 至少99%).

leevihua

這個帖真的非常專業,讓人大開眼界啊~

pfg1group

http://www.janes.com/defence/news/jdw/jdw060505_1_n.shtml

Special Report: UAVs - frontline flyers

By Alon Ben David JDW Correspondent
Tel Aviv
Robert Hewson Editor of Jane's Air Launched Weapons
London
Damian Kemp Jane's Aviation Desk Editor
London
and Stephen Trimble JDW Americas Bureau Chief
Washington, DC

The worth of unmanned aerial vehicles (UAVs) has been known for decades, with Israel leading the way in both reconnaissance UAVs and combat UAVs (UCAVS).

The increased tempo of US combat operations using UAVs, particularly their continued use in both Iraq and Afghanistan, as well as for border and maritime patrol, reflects the changed mindset of armed forces around the world.

The acknowledgement, particularly in Europe, that the next generation of aircraft after the Lockheed Martin F-35 Joint Strike Fighter (JSF) multirole combat aircraft is unlikely to be manned reiterates this shift.

Throughout the world UAVs are on the rise.

Recognised as a pioneer and world leader in the area of UAVs, Israel's last six years of low-intensity conflict with the Palestinians have led to a dramatic expansion of UAV roles and to further developments in operational doctrine.

"Out of 28,000 operational flight hours in 2005, 18,000 were conducted by UAVs, [which is] about 65 per cent," a senior Israel Air Force (IAF) officer told Jane's.

The IAF is responsible for operating all UAVs from the tactical level and up in the Israel Defence Force (IDF) and for providing UAV services for the ground forces and the navy.

"The constant fighting in the Palestinian territories, especially in the Gaza Strip, is creating a growing demand for UAV hours, which we more than doubled in the last [few] years," according to the source.

"Two UAVs could provide a commander with a constant 24-hour surveillance coverage of an area - something that in the past required the operation of at least six Tzofit imagery intelligence [IMINT] aircraft [based on a King Air 200], which meant the mobilisation of a whole squadron," said retired brigadier Mickey Bar, former head of rotorcraft operations in the IAF and currently head of Israel Aircraft Industries' (IAI's) Military Aircraft Group.

Palestinian eyewitnesses have claimed that Israel has been operating armed UAVs in the West Bank and Gaza that take part in precision attacks. The IDF has not confirmed these reports.

"Some of the manned platforms existing today have no advantage over the unmanned," said Bar. "Looking ahead at the future JSF, by the time it becomes operational, UAVs could provide the same if not better capabilities, negating the need to acquire such expensive platforms. By the end of the next decade, I believe that more than half of IAF platforms will be unmanned."

369 of 7,579 words

pfg1group

http://www.janes.com/defence/air ... idr050811_1_n.shtml

Tactical UAVs: redefining and refining the breed

By Bill Sweetman

Operational unmanned aerial vehicles (UAVs) today cover a vast spectrum, from hand-launched aircraft to the 14.6 t RQ-4B Global Hawk. Between these two extremes, the definition of different UAV classes is fluid and rapidly changing, as operators proliferate worldwide and build up hours at an unprecedented rate.

In particular, the concept of a 'tactical' UAV (TUAV) is hard to define. Hand-launched UAVs are tactical systems, designed for quick response to a front-line need for information. But the US Army uses General Atomics I-Gnat UAVs in Iraq for reconnaissance ahead of supply convoys, and the US Air Force (USAF) uses Predators for close air support. Those are tactical missions, performed by endurance UAVs.

Two related trends are apparent. One of them is a watershed split, based on mobility. On one side of the split are UAVs that operate from rear-area runways, but have the range and endurance to support forward-deployed troops for 12 hours or more per sortie; on the other side are UAVs that can move with ground forces, and are owned and controlled by those forces at all times. The US Special Operations Command, for example, is pursuing both man-portable and endurance systems, but not anything in between.

The other trend is that UAVs linked to ground forces are - one way or another - becoming more mobile. Many in-service TUAVs move with a long baggage train of catapults, cranes and control stations carried on medium trucks. Some new TUAVs on the market are designed to move themselves, like Fire Scout, or to be carried on a HMMWV-sized vehicle. There are even signs of a new UAV class that fits between the classic 250 kg TUAV and the tiny hand-launched vehicle.