So I am starting a new school term and I need a project for my Master's class in embedded real-time software systems. I am thinking of trying to convince the doctor to let me do a traditional heli UAV. In order to do this for the cheapest price I was going to try the Trex 450 clone with the Turnigy 9X transmitter and the APM2. I know on the scale of 1- 10 hardness of a semester project this might fall in the range of 12 but I am checking it out anyways. (Cause Helicopters are cool, man)
Is there anyone who has a lot of experience building these things that can give me a hint or two on a few things. I have read the wiki posts and the discussion board. I am however looking for a few suggestions.
- How doable is it to setup and learn to fly the traditional helicopter using APM within 4 months? This is the term of the class.
- I am thinking of linking the throttle into the APM (via the governor) to do as a software project. Is this doable? (the idea is to have the throttle adjust so that the wing pitch does not allow the wings to stall at the same time use minimal throttle to conserve power)
- If not, are there any suggestions that I can use to change the APM software to make the project interesting?
- If so, is there anyone who has tried this before? I saw a discussion thread on it but there was no outcome.
- Is there any problem with using the Trex 450 clone from hobby king? I only ask because the prices on that site are very low.
- As part of the project I will tie sonar to the airframe for auto takeoff and landing. I was going to use the same methods as the multicomputer. Any issues?
- Since the new APM2 comes with the gyroscope on board is it necessary to use the external gyro?
- Is there a coding guide to the APM2?
- Any hint on how to debug the program without crashing into the ground? I do not want to end up like Morpheus. I already know to keep the feed voltage to the APM under 5 V.
- Any suggestions as to a remote switch that will take the APM out of the system and return to manual control? As I am changing the software I want to make sure that I can take the APM2 out of the system if there is a bug.
I am willing to help update the wiki as I go through this process if there is any moderator that wants to approve my changes. I have over 10 years of commercial software development experience so it is not the code that is scaring me, it is the hardware.
Thanks in advance.
Replies
Moved the thread to Autopilot software/algorithms since I will prob not do a traditional heli
Thanks for all the reply's I am still looking for the project but it looks like the Traditional Heli might be too big of an ask, unless I can convince the professor of an exploratory project. I really do appreciate your input. Does anyone know if the JDrones quad kit comes with the latest APM 2.5 or do I have to buy that extra?
I would still like to help out with the code set however I would have problems doing so until I get a platform to test on.
Yeah... honestly, learning to build and fly a Trad Heli in 4 months... I wouldn't recommend trying. Here are a few cliches about helicopters:
1) Helicopters don't really fly, they just vibrate so badly the ground rejects them. (and remember, the APM does not like vibes!)
2) You couldn't afford to fly a helicopter even if it was free.
I think if you were skilled, and could tackle this FULL TIME for 4 months, maybe. But if it's like 2 hours a day? No way.
I have two clones, a 450 and a 600. The 600 was kinda junky, but it worked. A few of the parts are no good. Well, basically anything that is supposed to be round and straight, needs to be replaced. ;) Actually one of the big problems I find is that the metal is too soft. Any little bump and things bend.
Still, when you are learning, you crash a lot anyway, and even an Align will break. That's how I look at it.
The 450 Pro FBL is actually quite good quality. The only real problem with it is the main shaft was not round or straight. But otherwise, very impressive. Likewise, I'd suggest the HK550GT as it's newer than the 600, and I'm guessing the parts are higher quality, like the 450 Pro which is also a newer kit.
I'm currently building up a 550, but basically it's a conglomeration of aftermarket parts.
Align kits are good, but the problem is you usually have to take their electronics as a package, and I don't like that.
A couple more things..
I use an original trex450 because I wanted to reduce the possibility of hardware issues because when i started there was no tradheli support. Robert uses a trex600 clone. I suspect a clone is ok but you should probably make sure you get decent digital servos and I believe some parts will need to be replaced with real align parts but I can't tell you which ones exactly.
By the way a flybarless head is much better at least when it comes to using the autopilot for loiter and waypoints.
Pat,
Regarding your original question, it's possible to get a Trex flying with the APM2 (or 2.5 would be better) within 4 months. The code is mostly identical to the quad code including such things as autoland.
There is a MUX on the APM (channel 8) which you can engage from your radio and which allows the remaining 7 channels from your radio to pass through the APM2 and out to the servos untouched. This doesn't really help out with heli's though because the APM2 tradheli code requires that your input be unmixed (i.e. roll, pitch, throttle and yaw must be fed into the APM2's 1,2,3 and 4 input channels). So when you engage the mux unmixed output would be passed through to the servos which will just make your servos move in weird ways that certainly won't keep it airborn for more than a couple of seconds.
When it comes to cost, once you factor in mechanical failures (because they're more complex) and repair costs (from inevitable crashes on either platform), a quad is certainly cheaper and easier than a trad heli.
We could of course really use your help on the tradheli code and you'll find that Robert Lefebvre and I are around to answer your questions and give some guidance but the choice is all yours!
Hi,
sorry I cannot answer any of your questions, however I am curious: What will the objective of your Master Thesis be? I thought that traditional helis are already flying with the apm, are they not?
phil