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Archive 2014 · UAVs

  
 
R.H. Johnson
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p.1 #1 · p.1 #1 · UAVs


is anyone on FM using mirror-less cameras ie. Sony A7, EOS-M, or equivalent for aerial video photography/stills? i am just starting my research and analysis of UAV's, firmware/software, autonomous avoidance systems, UHF/VHF transmitter receiver flight control systems, GPS, and autonomous gimbal systems, etc. i am interested in building a robust UAV capable of a 10-20 lbs payload. if anyone that has hands on experience with UAV systems, can you sound in. your input would be greatly appreciated.

Edited on Dec 14, 2014 at 08:28 PM · View previous versions



Dec 14, 2014 at 05:12 PM
Cicopo
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p.1 #2 · p.1 #2 · UAVs


These sites might be useful.

http://www.rcgroups.com/forums/channels.php?id=34

http://www.aplanding.com/forums/index.php

http://www.rcgroups.com/fpv-talk-469/



Dec 14, 2014 at 05:32 PM
jcolwell
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p.1 #3 · p.1 #3 · UAVs


Hi R.H.,

I notice this is also posted on the General forum,

https://www.fredmiranda.com/forum/topic/1335857

For future refefrence, Fred recently introduced a way to cross-post the same thread on different forums. It's great, because all replies from both forums go to the same thread. Saves time and let's everybody see what's up.

Here's the announcement and description of the new cross-posting feature,

https://www.fredmiranda.com/forum/topic/1333789




Edited on Dec 14, 2014 at 08:16 PM · View previous versions



Dec 14, 2014 at 07:57 PM
Cicopo
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p.1 #4 · p.1 #4 · UAVs


This thread may help too.

http://www.rccanada.ca/rccforum/showthread.php?t=231385



Dec 14, 2014 at 08:09 PM
Access
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p.1 #5 · p.1 #5 · UAVs


Be ready to spend lots of money, more than $5000. for that. And be ready to lose all that if something goes wrong. So I always recommend starting small, getting the experience with something basic and inexpensive, before moving up to the big boys.

Also, the more weight you carry, the shorter your flight time. Try to keep things as light and simple as possible. This, for instance, is the drone I use for live surveillance, no gimbal or anything fancy, no FPV (not designed for non-LOS flight), but it does the job it was designed to do and gets ~15 minutes flight time in good conditions (or around 10 minutes in poor conditions). And all in all, cost less than $1000. to build.



There are ready-made hobbyist drones you can buy, and these are good because if you break it, you can just buy another one. The higher end among these have some basic features like GPS hold, go home, and auto-landing, but nothing advanced like waypoints or live navigation. But I'm not aware of any hobbyist drone that will carry that much payload.

Before anything, I would consider exactly what problem you are trying to solve -- whether it's simple surveillance, fine photography, video, long-range flight, etc., then decide the platform based on that. Don't over-design because you'll only kill yourself with weight and complexity.

Edited on Dec 14, 2014 at 08:32 PM · View previous versions



Dec 14, 2014 at 08:26 PM
R.H. Johnson
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p.1 #6 · p.1 #6 · UAVs


Cicopo, thanks for the links. good information, too.


Dec 14, 2014 at 08:29 PM
R.H. Johnson
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p.1 #7 · p.1 #7 · UAVs


jcolwell, thanks for the cross link info. that is a very good feature, by the way. this could get very interesting with more participants.


Dec 14, 2014 at 08:31 PM
R.H. Johnson
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p.1 #8 · p.1 #8 · UAVs


Access, fine photography, video, long-range flight are my objective. one would like to do some innovative wild life photography and video as well. i do not like the idea of a go pro. thus, the initial question in the OP. A7, EOS-M, or equivalent mirror less camera system for weight and still/video image quality.

one hopes to be able to use my engineering skills (i am a retired RF Analog electronics & software engineer) to increase the flight time of said UAV if possible. for instance EOS-M vs. 5D MKIII oz. vs LBS. what the UAV looses in camera weight it can carry in battery weight. this should hypothetically increase Flight Time and range. i have encountered specs for UAVs that can lift 10-20 lbs of pay load.

http://www.dji.com/product/spreading-wings-s1000-plus



Dec 14, 2014 at 09:14 PM
Cicopo
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p.1 #9 · p.1 #9 · UAVs


Are you aware of the fact the FAA & Transport Canada are putting regulations into place limiting flights to LOS ONLY (Line of Sight). If you can't see it with the naked eye (eye glasses allowed) you'll be in violation once these pass into law.


Dec 14, 2014 at 09:40 PM
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p.1 #10 · p.1 #10 · UAVs


OK, I see. The problem with flight time is that batteries add weight, so adding a larger battery is diminishing returns until it doesn't help at all. And battery energy density (of the best lithium-ion batteries) hasn't improved much at all over the last 10 years. In this way, it can be difficult to get anything that stays in the air for more than around an hour, and half an hour when you're carrying extra weight.

If you are software, embedded systems esp., a lot of the early quadcopter work was done with arduino setups. The nice thing about this is it makes the servo and motor control very easy, if you are designing something from scratch and have that kind of experience to customize control firmware, that might be a good starting point.

If you have a chance, to go the UAVSI show,
http://www.auvsishow.org/auvsi2015/public/enter.aspx
this will give you an idea what is out there, what other people are doing, and how much things cost.

BTW I the link to the DJI product you posted, I actually saw one of those at a local hobby shop just the other day. Nice setup, seemed lightly used, being sold for roughly $5000. (can't remember the exact price, and I don't think it included the gimbal). So I think that is the general price range for starting out with one of those things.


Used with a 6S 15000mAh battery, it can fly for up to 15 minutes.*
*Maximum flight time is tested on a windless day with a payload of 9.5kg, hovering at a height of 2 meters.


First, that battery alone, probably weighs a little more than 2 kg. And hovering a 2 meters, it probably hasn't fully left ground effect, and hence gets some benefit from that. How realistic a windless day is (or isn't) depends on where you live. But if you want to do a quick sanity check, let's say that payload of 9.5kg was mostly dedicated to additional batteries. With an additional 3 batteries of that type (~7kg), you might be able to make something that stays up an hour (if all you do is hover stationary at a low altitude), but that only leaves you with about 3.5kg for everything else. And once you start to maneuver around, your flight time will likely drop to around 30 minutes.

Now take a look at the same setup, without all that extra weight. If it draws 1000mAH per minute of flight when weighing a total of roughly 16kg, dropping the weight to only a single 6S 15000mAH battery and nothing else would put you around 6.5kg, so presumably it would only draw around 400mAH per minute of flight (if the relationship is purely linear) rather than 1000mAH. Add the same 3.5kg and you're up to 10kg, but that would likely still give you around 23 minutes hovering at a low altitude and that hopefully illustrates the diminishing returns you get when additional batteries.



Dec 14, 2014 at 09:50 PM
R.H. Johnson
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p.1 #11 · p.1 #11 · UAVs


Access, understood. maybe fuel cell technology is worth looking at. this is the beauty of communication and exchange of knowledge. point taken.

Cicopo, i would doubt if FAA or western rule would apply in more remote areas of the earth. the Serengeti comes to mind.



Dec 14, 2014 at 11:35 PM
R.H. Johnson
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p.1 #12 · p.1 #12 · UAVs


"you might be able to make something that stays up an hour (if all you do is hover stationary at a low altitude), but that only leaves you with about 3.5kg for everything else"

EOS-M + 55-200mm f4.5/6.3 EOS-M STM lens = .52276 Kg

3.5 Kg - .52276 Kg = 2.97724 Kg for every thing else

hmmm, might be doable.



Dec 15, 2014 at 12:30 AM
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p.1 #13 · p.1 #13 · UAVs


Yeah, just keep in mind that those batteries, if you want decent ones, will run you at least $600. apiece.

Youtube is a good place to look for videos of these types of drones, ie. S1000 + 5d3 setup:



for more:
http://www.youtube.com/results?search_query=S1000



Dec 15, 2014 at 12:50 AM
pmiller228
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p.1 #14 · p.1 #14 · UAVs


If you really want to go nuts


http://hackaday.io/project/1230-goliath-a-gas-powered-quadcopter



Dec 15, 2014 at 02:06 PM
rattlebonez
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p.1 #15 · p.1 #15 · UAVs


It will be fun with the UAV frequency jammers are released.
People will crash the UAV when its owner is lurking, spying, etc.



Dec 15, 2014 at 02:15 PM
EB-1
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p.1 #16 · p.1 #16 · UAVs


rattlebonez wrote:
It will be fun with the UAV frequency jammers are released.
People will crash the UAV when its owner is lurking, spying, etc.


I think they are programmed to return to base when signal is lost. You need to jam the GPS as well. Perhaps some sort of one-shot kamikaze UAV could be developed to seek and destroy the invading UAVs. It would only have to have enough range to protect your property.

EBH



Dec 15, 2014 at 03:56 PM
howardm4
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p.1 #17 · p.1 #17 · UAVs


rattlebonez wrote:
It will be fun with the UAV frequency jammers are released.
People will crash the UAV when its owner is lurking, spying, etc.


Everyone is using spread-spectrum frequency-hopping technology these days so you can forget
anything like a simple jammer.



Dec 15, 2014 at 04:08 PM
R.H. Johnson
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p.1 #18 · p.1 #18 · UAVs


Access great links. thank you.

question: the gimbals don't appear to be center of gravity balanced? just wondering if a long Q-plate mounted to the camera base and balanced would improve the weight handling capability of the gimbal. keep in mind that i don't own and have never held one of these gimbals. just an observation from my perspective. thus far it seems that the gimbal is unit specific ie. in the first link above the pilot mentions in the video that the gimbal is set-up specifically for his camera lens combo. this implies that the gimbal firmware is specially programmed for that set-up taking to account for the lens forward weight. if this is the case the gimbal set-up is very limited. are the gimbals programmable per camera lens combination? if not centering the camera lens combination via Q-plate should make the gimbal function some what like a gimbal super telephoto set-up. hmmm, this is going to be an adventure.

protect your property from what? do you jam the government as well when they fly over? besides UAVs are cost prohibitive and technologically complex. not exactly joe sixpack ready presently. how evil, is it to willing destroy or even jam some one's UAVs, sick.....

spread-spectrum now that's a term i haven't heard in a long time. add a little encryption military grade non jam-able UAVs.



Edited on Dec 15, 2014 at 04:45 PM · View previous versions



Dec 15, 2014 at 04:42 PM
Access
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p.1 #19 · p.1 #19 · UAVs


EB-1 wrote:
I think they are programmed to return to base when signal is lost. You need to jam the GPS as well. Perhaps some sort of one-shot kamikaze UAV could be developed to seek and destroy the invading UAVs. It would only have to have enough range to protect your property.

Some will, but 'go home' doesn't always work flawlessly.
Typically the algorhythm is, rise to a certain altitude, then take the shortest path back home (as the crow flies), and then try to land. So if there is any obstacle in the way, it will crash.

R.H. Johnson wrote:
question: the gimbals don't appear to be center of gravity balanced? just wondering if a long Q-plate mounted to the camera base and balanced would improve the weight handling capability of the gimbal. keep in mind that i don't own and have never held one of these gimbals. just an observation from my perspective. thus far it seems that the

For the most part, the gimbals used on copter drones are designed specifically for that platform. They're supposed to operate and provide stabilization in a high-vibration environment, so the joints are very 'loose' with a lot of give, and the motors don't exert a lot of actual force. If it's not balanced just right (ie. camera too heavy or too light), it will struggle and be unable to control the camera or even just hold it steady.

And most do hang from a roll-joint, in order to stay level with the ground as the copter rolls.

R.H. Johnson wrote:
spread-spectrum now that's a term i haven't heard in a long time. add a little encryption military grade non jam-able UAVs.

The off-the-shelf spread spectrum systems can be jammed (or at least impaired) simply by switching on a lot of transmitters at the same time. Also the ISM band (which most of the off-the-shelf stuff uses) is getting pretty crowded these days. I always use 5.8GHz for the live feed if I can, and the guys that do the really long range flying will use the dedicated bands that require one type of license or another. And it's always good to have backups for critical controls.

Another thing to add, DJI craft tend to suffer from the 'flip of death', the prevalence of which is open to debate.
https://www.youtube.com/results?search_query=DJI+flip+of+death

Edited on Dec 15, 2014 at 05:09 PM · View previous versions



Dec 15, 2014 at 04:43 PM
R.H. Johnson
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p.1 #20 · p.1 #20 · UAVs


"Some will, but 'go home' doesn't always work flawlessly.
Typically the algorhythm is, rise to a certain altitude, then take the shortest path back home (as the crow flies), and then try to land. So if there is any obstacle in the way, it will crash."

The Panoptes eBumper provides operator augmentation and precision aircraft control to the experienced pilot flying in cluttered environments. Protecting against wind gusts or erroneous user input, the eBumper is an integrated set of sensors and avionics that is simple to install and use. by adding sensors in the front, left, right and on top, obstacles in the field of view can be detected, and a stopping maneuver can be initiated.

eBumper warrants looking into for in-flight autonomous object avoidance to initiate an auto routine to avoid objects in the flight path.

http://www.panoptesuav.com/ebumper-operator-augmentation



Dec 15, 2014 at 05:00 PM





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