Constructing a UAV with a DSLR camera gimbal

A

apeak

Member
We have done a fair amount of research, and have ended up with a reasonable idea of how to structure a UAV. If you spot any weaknesses or problems, please do not hesitate to reply.

We are building a 'Hexacopter’, since we need stability and power enough to carry a relatively heavy DSLR, as the 5D/7D. The entire structure along with camera, gimbal, motors, battery, etc. we believe will weigh apx. 6kg. We imagine the frame manufactured in carbon fiber, so that it is both light and maintains stability.

The controller is thought to be the Arduino-based platform called 'ArduCopter' (http://code.google.com/p/arducopter/wiki/ArduCopter)

The purpose of Ardupilot is that it should be easy and accessible to gain control of all input from the gyroscope, accelerometer, gps, etc. as we do not have a lot of experience with these sensors.

All these inputs come from APM2.5 (https://store.diydrones.com/APM_2_5_Kit_p/br-ardupilotmega-06.htm), which should have all the necessary sensors and is easy to connect to a computer, and (hopefully) easy to calibrate.

The engines are thought to be 880kV, which together with its blades should give hexacopter an upthrust at 1200g per engine v. 75% (roughly around 7kg for all six engines). It's all available in this set along with ESC’s, propellers and distributionboard:
http://www.buildyourowndrone.co.uk/HexaCopter-Full-Motor-ESC-Set-880Kv-p/ach-fmk88.htm

Can you possibly see any weaknesses in this setup?

Regarding the camera-gimbal we haven’t completed our research yet, but wish to make it controllable in 3-axis. We are considering using a powerful servo called “Savox SC-1258-TG”, and using http://photoshipone.com/3x-pro-v2/ or http://www.averticalview.com/ as inspiration.

We also bought a 6-channel remote control "Spektrum DX6i" which probably is best served controlling the camera-gimbal.
How many channels do we need to control the hexacopter?
We don't have any idea about which battery to use, do anyone have any idea how to choose this?

Any help would be much appreciated….We have done a fair amount of research, and have ended up with a reasonable idea of how to structure a UAV. If you spot any weaknesses or problems, please do not hesitate to reply.

We are building a 'Hexacopter’, since we need stability and power enough to carry a relatively heavy DSLR, as the 5D/7D. The entire structure along with camera, gimbal, motors, battery, etc. we believe will weigh apx. 6kg. We imagine the frame manufactured in carbon fiber, so that it is both light and maintains stability.

The controller is thought to be the Arduino-based platform called 'ArduCopter' (http://code.google.com/p/arducopter/wiki/ArduCopter)

The purpose of Ardupilot is that it should be easy and accessible to gain control of all input from the gyroscope, accelerometer, gps, etc. as we do not have a lot of experience with these sensors.

All these inputs come from APM2.5 (https://store.diydrones.com/APM_2_5_Kit_p/br-ardupilotmega-06.htm), which should have all the necessary sensors and is easy to connect to a computer, and (hopefully) easy to calibrate.

The engines are thought to be 880kV, which together with its blades should give hexacopter an upthrust at 1200g per engine v. 75% (roughly around 7kg for all six engines). It's all available in this set along with ESC’s, propellers and distributionboard:
http://www.buildyourowndrone.co.uk/HexaCopter-Full-Motor-ESC-Set-880Kv-p/ach-fmk88.htm

Can you possibly see any weaknesses in this setup?

Regarding the camera-gimbal we haven’t completed our research yet, but wish to make it controllable in 3-axis. We are considering using a powerful servo called “Savox SC-1258-TG”, and using http://photoshipone.com/3x-pro-v2/ or http://www.averticalview.com/ as inspiration.

We also bought a 6-channel remote control "Spektrum DX6i" which probably is best served controlling the camera-gimbal.
How many channels do we need to control the hexacopter?
We don't have any idea about which battery to use, do anyone have any idea how to choose this?

Any help would be much appreciated….
 

kloner

kloner

Aerial DP
just from the little i know, your gonna find yourself in a continuous loop trying to tune something like the arduindo when you should be making money with it. you could save a whole lotta time and make alot more money with something like wookong. it is for the most part plug a play. others to consider would be hoverfly and zero uav
 

flitelab

flitelab

Member
Agreed with kloner, if your goal is to do actual photo work then I'd get a known working aircraft ARF setup. Otherwise your in for some learning and tuning to piece together a system. So many factors invovled that it is best to start with a known working system especially if you are totlaly new to multirotors and RC.

"and (hopefully) easy to calibrate." - It wont be...
 


J

jes1111

Active Member
You also don't have the right motors there. You've calculated maximum available thrust at 70% of the AUW of the craft - that figure should be 50%, i.e. you are hovering (thrust = mass) at 50% throttle - then you'll have the ability to climb/descend and still retain the margin necessary for the controller to stabilise the vehicle. Motors would need to be somewhat larger - around 110-120g. I think you total weight will come closer to 7kg, btw.

You can benefit tremendously at this stage from learning the ins and outs of http://www.ecalc.ch/xcoptercalc_e.htm?ecalc.

Where are you based? Europe? USA? If you fill in that info on your profile here, people will be able to guide you to specific vendors.

Good luck! :)
 

A

apeak

Member
Thanks for the replies! Great to get some feedback...

We're doing this as a school-project, therefore we would like to construct it ourselves, and not buy a pre-built solution. Do you know any type of "motor/rotor-blade/ESC/Distributionboard"-combination that would be feasible for our demands?
Would you recomend another system than the ardupilot? We are located in Denmark, Europe, so European vendors are preferable. Thanks again!
 

J

jes1111

Active Member
This chart http://www.droidworx.com.au/specifications.html is useful: find a combination on there that corresponds to your requirements, then work backwards by studying the specs of the suggested motors and locating cheaper alternatives with similar specifications.

You might be better off starting by building something smaller (to carry a smaller camera) - it's the "DSLR" part of your requirement that greatly increases the complexity and prices. ;)
 

kloner

kloner

Aerial DP
jes, is anybody in here running a dslr and flying it? seems like most use mirrorless, then theres a group with reds. maybe i didn't pay atention
 

R

R_Lefebvre

Arducopter Developer
kloner said:
just from the little i know, your gonna find yourself in a continuous loop trying to tune something like the arduindo when you should be making money with it. you could save a whole lotta time and make alot more money with something like wookong. it is for the most part plug a play. others to consider would be hoverfly and zero uav
Click to expand...

I feel pretty comfortable now saying that that isn't true anymore. I'm not a "company man", and in the past have gone on record saying that the system was not yet "stable". But it is now.

I assembled a 3DR Quad, uploaded the code, and didn't touch a single setting, and it flew perfectly straight off. Ever since release 2.6, we're hearing lots of success stories. It may be true that Arducopter will require more tuning than Wookong (I've never used one), but it's is equally true that it *allows* more tuning. I have heard from some people that they simply can't get Wookong to work on their system.

The 6-channel setup will run Arducopter, but you won't be able to take full advantage of it. You need 4 channels for basic flight control, Ch5 is for mode selection, Ch6 is for live tuning of parameters (this is VERY useful and greatly speeds up tuning!) or gimbal tilt setting, and Ch 7 is used for a number of functions, such as activating Simple Mode, RTL, in-air leveling, etc. Ch8 is not currently used for multi-rotors, but might be in the future. It could be used similar to Ch6. It is also used to control ESC's on Helicopters.

The only bit that's hard about tuning Arducopter now, is just the shear number of features, and tunable settings. It's a double-edged sword. If a feature doesn't exist, then you don't have to learn how to use it. If it's not tunable, then you don't have to tune it. Some people simply get overwhelmed and/or confused. It even happens to me... I was flying on the weekend, and switched Ch7 high for simple mode, only I had forgot that I had changed it to Auto-Trim instead. I was chasing the thing all over the sky until I realized what I'd done. Luckily I was able to figure out what I'd done, realize it's not in simple mode, re-level it, and then land.
 

kloner

kloner

Aerial DP
will it run 8 motors? wookong has 2 ch for gains so can split it into 2 switches to fine tune. 2 switches for the gimble, automated take of and landing? ppm and sbus in? waypoints? return to home? inteligent orientation for beginers?

I've been going over all the readily available controllers but never even looked at the open source stuff. i bought one, blue newest kk board, i had a brick in 2 minutes, never looked back. you almost can't screw up with something like dji controlers

yea, all them settings is what totaly turns me off. i'm a wait for the next firmware guy versus letting me touch the dials. I saw a guy with a totalG screw with it till the helicopter exploded on the wing, ever since i realized i shouldn't touch dials i don't fully understand

What is the full feature list on that thing? wheres the site to look at?
 

R

R_Lefebvre

Arducopter Developer
Yes, absolutely 8 motors. It has 11 outputs (technically 12, but really 11, don't ask) so it can theoretically do an Octo, with 3 axis gimbal, but I don't think anybody has actually done that yet.

Automated takeoff, what exactly do you mean? It will theoretically do a scripted mission, right from take-off. I haven't seen anybody do that yet.

Automated landing, yes, but not well. I wouldn't trust anything big and expensive or with a camera hanging from it. If you have a play quad like a flamewheel, sure. It tends to set down pretty hard and/or bounce and skip over the ground until it actually realizes that it has landed. Therefore, they created "Auto Approach" mode instead, for the big machines. It will come, and then drop down to some altitude, whatever you want, like 1m, 2m, 5m... and just wait there.

PPM in, absolutely. SBus, no.

Waypoints, yeah, a huge number, something like 100. RTL, absolutely, I've used it.

What is intelligent orientation? "Simple Mode", where pushing up always moves it away from you, left always moves it to the left of you, etc? Yes. And Super Simple mode, which I believe what it does knows where you took off from and rotates the orientation around that point. So you could fly circles around yourself as you turn your body around. I haven't used this. Honestly, I'm not a huge fan of simple mode, I think people should learn how to fly properly. I think it's a crutch, and prevents some people learning to fly, which eventually causes problems. I only really use it as a bailout.

I can't guarantee you won't brick it. But I have yet to do it, and I don't see that much.

You can't just wait for the firmware, you will have to learn how to tune it. Because the tuning is fairly unique to each machine, unless you build something exactly like the mainstream machine.

The main site is www.DIYDrones.com, and there's a wiki (though it's not perfect, you'll get the idea).

Honestly if you don't like to tinker, it might not be for you. You will likely need to tinker with the settings, and also tinker just to use some of the features. We are trying to make everything more user friendly, but there's a LOT of features!

Other features, awesome ground control. Click to fly here. Huge number of waypoints and unlimited range. Points of Interest. Follow me (never seen it used yet). Antenna tracking built-in. Awesome stuff.

Another feature, geo-fencing. This is pretty cool, but I don't think it's fully functional yet. Hopefully they finish it, because it's a big deal, IMO.

I could go on and on.

If somebody wants plug and play, ease of use, this isn't it. If you want to *learn* about these, and use them at a high level, you're in academics, it's the way to go.
 


R

R_Lefebvre

Arducopter Developer
Geofencing, basically you can set up a box, or a cylinder, with a top and a bottom, and if you go outside that, I think you can choose it to do a number of different things, such as to return to home, or "bounce off". I haven't used it yet so I don't know how well or easy it works. I know it is really flawed, because if you set a bottom on it, min altitude, when you want to land, it won't let you. You have to go to your ground control station, and then turn off the geofence, then land. I think that's really not great. It should be on a switch or something.
 

E

E-Copter

Member
Hi,

the GeoFencing is exaclty what sayt's the name : it's a digital Géographical Fence. The UAV is not allowed to run out the delimited space, and if it does, then you can program different scenarios.
This features is used in other systems as " max radius and height flight limitation" and in France you need this feature as what they call a " failcrash" (weird name), the UAV has to auto land and stop it's engines if you try to push it too much to get out of the " geofence".

Best regards,

Fabien

PS: auto take off and land works for sure and fairly well on a few systems, but you need to set the idle ( min rotation speed of motor when arming the multi) and the descent rate and cutoff delay well so it can work correct. And for auto take off you need to give it a good velocity for the take off or it will flip over to fight an unknown state of altitude. There are some systems better made than some others on that side :)

BEst regards,

Fabien
 

A

apeak

Member
If we're are to find a reliable combination of propellers, ESC's and motors to support a hexacopter construction weighing around 7kg (camera included) what is the best way to go about this? any good suppliers in Europe? Thank you very much!
 

E

E-Copter

Member
Hi,

very sorry for my late answer,

YOu ill need motors like the Axi (mainly used on Cinestar frames), or Plettenberg ( these are the motors i would go with personaly) with Xoar 14' props ( wooden or carbon ones).

For Esc's, depending on the flight controller you will use, you can go for Aerodrive ( but really expensive..) or use some MGM Compro Esc's, the X32 series are just insane for multitoror usage ( they have an active throttle, very very fast, allowing really hig control on fast descent or yaw).
You can find all props and motors a bit everywhere in Europe, for the ESC's you need to go through MGM themselve ( ask for Grigorij :) ).

BEst regards,
Fabien
 

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