Best platform for an INDOOR UAV contest?

[zlite]

I've been working with a big organization that wants to start an indoor aerial robotics contest for kids (6th grade through high school). They're looking for advice on the best standard reference airframe and rules, and at this point the main question is lighter-than-air or heavier-than-air? The aim is that it be: A) SAFE; B) cheap; C) easy enough for smart kids and a coach or two to do. Ideally, it could use a Lego Mindstorms NXT brick as the CPU.

The pros and cons for me look like this:

--Lighter-than-air (blimp): safe, but hard to control, big (if it's carrying any kind of serious payload) and very fiddly to set up.

--Heavier-than-air (quadcopters, microlight indoor planes, etc): potentially too dangerous for kids, crash-prone, harder to achieve basic controlled flight, but better lifting power, easier to control one you've got the basics sorted, useable in a smaller space and overall a more flexible platform.

What do you think? Any suggestions or links to appropriate platforms?

[Terry S]

Blimp is the only way.

Terry

[DiamondMox]

or a 4 rotar dragonfly

[Capt. Crunch]

Better talk to your basketball dept., in my experience they hate anythng other than rubber sole shoes from touching their floors. We can't find an indoor site in San Diego anymore.

BTW, it usually takes 2-3 years to coach a group of college students to make a flyable aircraft. Why not use trucks to run around and grab something or dump something?

that age group and aircraft don't do too well, unless you want to do everything for them!

[rblilja]

I would go with the blimp... But the payload weight will be the issue. I recall that my pretty small blimp (filled with "party"-class helium) managed to lift a small CCD camera and a 9V battery, that payload where near the limit.

If choosing the blimp, make sure you use good quality helium, and not a too small blimp.

-- Lilja

[JayFrancis]

The Lego NXT and RCX aren't very light. I can get you exact weights if you don't have them handy.

--Jay

[rblilja]

Oops, did miss that, sorry. Then the weight will be a real issue.

[zlite]

The RC 4-rotor Draganfly starts at around $700, which is a bit steep, but if it can be modded for fully autonomous flight, that could be a good choice. I've seen then in action and they don't seem likely to do much damage if they crash, although I gather that replacing parts can get expensive.

Anyone have any experience in turning the cheaper Dragafly's into a proper UAV?

[Magician]

zlite,

I really applaud your efforts to get kids/students involved in UAVs. An indoor venue would keep the weather issue out. However, what type of UAV task would you be doing? Finding a task or event that could be done without GPS may be interesting. I'm sure visual recognition is out!

My vote is for the blimp for safety and a greater chance of success through the testing phase. 7-10' envelopes aren't too expensive and they are easy to transport empty.

Good Luck,

Chris

[zlite]

Chris,

The aim is to simulate a robotic lunar landing, evoking the X-Prize Lunar cup.

My main concern about blimps is that they're very hard to control precisely due to air currents and momentum lag. I'm also not sure if something in the 6' range, which is about as big as we can handle, will have the lifting power necessary to carry a proper UAV payload. Have you had any success with robotic blimps indoors?

[Mick Molloy]

gws pico stik, cheap safe stable repairable....

[Unterhausen]

I've been avoiding commenting in this thread because I don't think you can do it, but I didn't want to say that because I wanted to be pleasantly surprised. On a more positive note, my thought is that since it is indoors, and thus range is limited, you could take the weight of the computer off of the uav, and put most of it on the ground. Of course, there are complications with this idea, like what sensors you could use and the telemetry. But a fully autonomous indoor craft doesn't seem possible without some technical advances.

[zlite]

Unterhausen,

There's no question that it's doable. Dozens of university and other research groups have demonstrated indoor UAVs from blimps (http://www.ias.uwe.ac.uk/People%20Pages/j-welsby/main.htm) (attached) to microplanes (http://www.techreview.com/Infotech/14753/) and helicopters (http://www.ida.liu.se/~patdo/moviii/MOVIII_070509_micro.pdf). There are already plenty of indoor UAV contests for university or above competitors, such as this one (http://www.supaero.fr/microdrone/flights.htm).

The only question is how to bring it below $1,000 and within the reach of kids.

[Unterhausen]

I know flying an aircraft indoors can be done, and you may actually be able to build an airframe all up for $1k. I want to be able to do it with my Picooz, but the tech isn't there.

The best platform may be the Blade CX2.
See these two examples:
http://www.tarbox.org/helicontrol.html
http://www.lylechamberlain.com/indoorcollisionavoidanceandnavigation

Here's a budget:
Gumstix Verdex, robostix and wifistix (or use bluetooth), $300, ask for donations :)

Blade CX2 $200, cheaper if you shop.

Sparkfun sensors: $50-$200 depending on your ambitions -- high end includes 5 axis imu.
tiny camera, $50, use the Verdex framegrabber.

Problem is that software development isn't cheap, particularly in terms of time.



Having a pc controlling a little heli would be really cool, and I think most
kids would be pretty blown away by that. You could use ground based cameras
for feedback and the trainer port on a radio for the computer control. Just have a big
red switch available for emergencies.

[hg1]

http://www.lylechamberlain.com/indoorcollisionavoidanceandnavigation

Having a pc controlling a little heli would be really cool, and I think most
kids would be pretty blown away by that. You could use ground based cameras
for feedback and the trainer port on a radio for the computer control. Just have a big
red switch available for emergencies.
That Lyle Chamberlain video is cool, but it implies a high level of technical skill. Along the same lines, check out some of the videos from the MIT Raven testbed - http://vertol.mit.edu/

I suspect that the best solution for this type of project will be found with quad rotor systems. The X-UFO with X3D controller is a reasonable starting point, and there should be comparable RTF airframes with brushless motors in the market at a reasonable cost within a year, so I wouldn't be discouraged, though it may take a bit of time before all of the pieces come together.

[Unterhausen]

the Raven testbed is almost exactly what I was thinking about. One of the pictures at your link shows a batch of transmitters hooked up to computers.

Quadrotors still seem like they are going to be pretty expensive.

[zlite]

The X-UFO with X3D controller is a reasonable starting point, and there should be comparable RTF airframes with brushless motors in the market at a reasonable cost within a year, so I wouldn't be discouraged, though it may take a bit of time before all of the pieces come together.

That's an excellent suggestion. Maybe if manufacturers knew that there was a potentially huge market of students looking for a relatively cheap, robust and simple quadcopter platform for robotics contests, they'd be rushing to create that RTF version.

Hey Silverlit! Go for it!

[hg1]

That's an excellent suggestion. Maybe if manufacturers knew that there was a potentially huge market of students looking for a relatively cheap, robust and simple quadcopter platform for robotics contests, they'd be rushing to create that RTF version.

I don't know that you will see the mass market hobby companies rush into this, but there a number of efforts on open uav and open quad designs that will lead to some reasonable costs.


the Raven testbed is almost exactly what I was thinking about. One of the pictures at your link shows a batch of transmitters hooked up to computers.
Quadrotors still seem like they are going to be pretty expensive.
For now, they might be, but I think this will change. I think X-UFO + X3D costs around $500-$600 now, but there is a lot of discussion and exploration brushless versions which include the IMU that will cost under $1000.

I have explored the route of controlling the Blade CX2, but it has a lot of vibration and is somewhat fragile. Coaxial rotors are interesting, and I have experimented with fixed blade coaxials in hopes of finding a low-cost solution (see http://www.rcgroups.com/forums/showthread.php?t=706462 ), though we are still struggling with fabrication issues as well as waiting for lighter weight motors, so that approach is not certain. I have been watching a number of different quad projects, and the basic mechanical simplicity is very attractive, so it is just a matter of bringing the costs of the controls to a reasonable level.

[Magician]

the Raven testbed is almost exactly what I was thinking about. One of the pictures at your link shows a batch of transmitters hooked up to computers.

I'm no expert on the MIT program but I recall reading that the navigation system was based on an external visual location system that was developed by Hollywood for special effects work. This explains the stands surrounding the demo space and the computers required to do the position crunching. This can't be cheap.

I still think that low cost indoor UAVs would be difficult due to the absense of GPS. Perhaps the indoor test facility at Stanford (I think) could be used. They have a huge GPS transparent roof for testing.

Chris

[hg1]

I'm no expert on the MIT program but I recall reading that the navigation system was based on an external visual location system that was developed by Hollywood for special effects work. This explains the stands surrounding the demo space and the computers required to do the position crunching. This can't be cheap.

That's right - they have been using an external location system from Vicon, but seem to be headed toward systems using onboard cameras.

[Unterhausen]

We do location (indoor GPS) with cameras for our robots. It's not very hard to do, as long as you aren't trying to keep track of multiple robots. Even then it's not hard unless you want to keep track of which one is where. These algorithms run on a standard PC. It doesn't surprise me that someone at MIT used a high dollar solution, but it's not like that is the only way to do it. I'm just hoping they borrowed it from someone, because it just doesn't meet any real-world needs for a UAV.

To some degree we're talking past each other because the goals weren't really stated, and we all have our ideas on what the goals are. I can't imagine that we are really talking about a $1000 fully autonomous air vehicle that can safely do complex indoor missions while being run by kids -- sometime in the next couple of months.

[hg1]

To some degree we're talking past each other because the goals weren't really stated, and we all have our ideas on what the goals are. I can't imagine that we are really talking about a $1000 fully autonomous air vehicle that can safely do complex indoor missions while being run by kids -- sometime in the next couple of months.No argument there.

Regarding MIT, I believe the intent is to work with cameras that are onboard the flyers rather than an external reference frame. But this is probably the topic of a different thread.

[tomsal]

If you are trying to build something like a Lunar Lander the Mini-JAR may be a good platrorm to start with. Very economical and quick to build and experiment with. See it here. (http://www.rcgroups.com/forums/showthread.php?t=459443)

[zlite]

To some degree we're talking past each other because the goals weren't really stated, and we all have our ideas on what the goals are. I can't imagine that we are really talking about a $1000 fully autonomous air vehicle that can safely do complex indoor missions while being run by kids -- sometime in the next couple of months.

Well, what we're trying to is to set goals that CAN be accomplished by teenagers indoors for under $1,000. Maybe it's no more than completing a course, with manual takeoff and landing. Maybe it will be just be an autonomous landing. The answer will depend on what UAV platforms and contest area technology (IR beacons? Tethers? Nets?) we settle on.

I assure you that I'm working with serious people with years of experience in robotics contests for kids. They wouldn't be embarking on this if they didn't think it was doable in the next year or two (nobody every said anything about the next few months).

My point in asking the question was to canvass opinion on some promising directions to explore. Over the next few months we'll be able to a proper technology assessment and then we'll be able to be more specific about what the attainable contest goals may be.

[hg1]

Well, what we're trying to is to set goals that CAN be accomplished by teenagers indoors for under $1,000. Maybe it's no more than completing a course, with manual takeoff and landing. Maybe it will be just be an autonomous landing. The answer will depend on what UAV platforms and contest area technology (IR beacons? Tethers? Nets?) we settle on.In the timeframe that you are considering, $1000 is a reasonable budget for a quad. As mentioned earlier, a reasonable alternative would be a more robust version of a Blade CX2 coaxial. As your program gets further along, perhaps you can talk about numbers of participating teams, as that may provide some motivation to potential suppliers - the FIRST robotics competitions have evolved into a mini industry.