Replies to This Discussion

ModeratorPermalink Reply by Sgt Ric on December 8, 2009 at 9:02pm

@Felix-
The term OSD is usually the telemetry data added visually onto the video downlink.

You are referring to the data the Xbees downlink to a groundstation.

@Oliver - do you mean you would just let an autopilot fly off over the horizon with no way of knowing its location, heading, speed, altitude, or even if it was still in the air? Then you must have "an awful lot of extra cash..."

Permalink Reply by Oliver Giess on December 8, 2009 at 10:09pm

No I would simply not leave my drone up there I would just take manual control and fly it back down to land. I dont plan on leaving my drone up in the air for hours atleast not without supervision.

Permalink Reply by Benjamin Lanehart on December 7, 2009 at 10:34pm

You should probably read these three links...

ArduPilot Main Page
Everything you need for a complete setup
ArduPilot Manual

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Permalink Reply by Felix on December 7, 2009 at 11:27pm

another question. with the ardupilot it says its optimized for the easystar plane and it goes on to say that u can modify ardu pilot for other airframes. how much modification is needed for use in a rudder, aileron and elevator plane?

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Permalink Reply by Felix on December 7, 2009 at 11:40pm

also can some one tell me what this is?!?! http://www.rangevideo.com/index.php?main_page=product_info&cPat..." target="_blank"> can u suse this instead of ardupilot or the XBee thing?!?! i have no idea

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DeveloperPermalink Reply by jasonshort on December 7, 2009 at 11:56pm

Do you mean the RVOSD? That link is broken.

I think you have some research to do. You won't get your questions answered in 10 minutes in a forum. I researched this stuff for 2 months and slowly bought pieces over a few months.

Check out http://readymaderc.com for some insight into what you can do. An autopilot just steers the plane automatically.

Jason

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Permalink Reply by Felix on December 8, 2009 at 12:07am

ah yeah thats the one it says that it does some kind of auto pilot?

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Permalink Reply by Benjamin Lanehart on December 7, 2009 at 11:35pm

From the manual:

"Tuning ArduPilot for your aircraft
Despite what you may have heard, there are no plug-and-play autopilots in the world ;-) Even the best autopilots need to be tuned for different airframes, configurations and use patterns, and doing so is a bit of a black art. ArduPilot is distributed tuned for a standard EasyStar in low wind conditions, and you should be able to use it pretty much as is for that. But just as every RC plane requires a little trimming to fly well, you'll find that your autopilot may peform better if you tweak various settings.

Our recommendation is that while you're first setting up ArduPilot for your aircraft, you do NOT use it to control the throttle. Rather than connecting the ESC through the ArduPilot, connect it straight to your RC receiver as usual. That way you can control the throttle manually while ArduPilot is controlling stabilization and navigation. The main reason for this is that it's very difficult to tune aircraft in the wind, especially if the throttle settings are not sufficient to make headway (when the aircraft is heading into the wind with a insufficient throttle setting, its ground speed may drop to zero, which will confuse the GPS navigation, which is based on ground speed). Manually keep the throttle high enough to make headway into the wind, and you'll find it much easier to observe and tweak stabalization and navigation gains.

For aircraft other than the EasyStar, you'll definitely need to change setting to get acceptable performance. Over time, we'll release additional [airframe].h settings files for other aircraft, starting with the EasyGlider, SuperStar EP and Funjet. Community members will no doubt share files for their own aircraft and over time this tuning process will get easier.

[The ArduPilot 2.3 code does not use the D term in the PID, so you only need to modify the P (proportional) and I (integrator terms). You can learn more about PID theory here.]

Here are some general guidelines on modifying the PID gain settings in Appendix 2:

First, the best way to set up stabilization is to do so in Fly-By-Wire mode. Disconnect the GPS on the ground, and then when you switch the autopilot on in the air, it will simply stabilize your RC controlling. Try it with your hands off the stick and then see how it recovers from rolls and pitching.

A general rule of thumb is to increase the proportional term until the plane starts to wing rock (roll) or porpoise (pitch), then reduce the P term to half that value. Then increase the I term until sufficient stability is achieved.

You can start with the default settings in the EasyStar.h file, but if you really want to optimize the autopilot for your aircraft and not overcontrol it. We recommend you start from very low values and build up. For example P=0.1 and I=0. And then increase P slowly until you see better response (.1).

Next, you can test navigation by trying RTL (Return to Launch) mode. This is the default mode for the up position of your RC transmitter's toggle switch. Point your plane away from you and switch into auto. It should return to you and circle overhead. Try from various directions, so you can see how the plane handles navigation into the wind, downwind, and crosswind. If everything checks out, you're ready to try waypoints."

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Permalink Reply by anaximander on December 16, 2009 at 2:06pm

Yeah, basically the XBee sends back everything that an ordinary plane would be showing the pilot on all the various dials - location, airspeed, altitude, attitude, heading, waypoint number, etc. The two main reasons for this are that we UAV builders are an inquisitive bunch and we like to see how our toy is behaving, and also that data can help you see how well it's doing, and spot errors before they cause problems, and if you decide to take over and fly manually you know what the plane is doing, so you're not jumping in blind. Also, it lets you plot the flights in Google Earth or something similar, so you can see where you flew and compare it to where you wanted to fly. If you don't want your UAV to send back all that data, then you don't need the XBee - I don't think it has the necessary bandwidth to handle video of much quality. If you want good-quality video relay, then something like that Range Video transmitter is what you want. Plus, the Range Video OSD can overlay telemetry data on the video, so you still get that data (although it'll be live only; pretty sure you can't log it that way).

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ModeratorPermalink Reply by Morli on December 16, 2009 at 3:14pm

@ Felix & other new comers,
FPV or First Person View / Fly via Personal Video is manned flying and as such not much to do with UAV which is Umanned Aerial Vehicle. The range video and similar stuff are more related to FPV and regular RC flying. This community is more like ex RC flyers who got bored with regular flying and want to do more than that. So" Do It Your self " as name implies much of it is done by your self which includes reading, understanding, building, testing and sharing the knowledge of your research. You will be doing your self a favour by starting reading the first page FAQs and where to start questions. It took most of us many months of patient reading and listening, researching each technical jargons/glossary, trolling WIKI for hours to even understand most of what is going on today. So pls read them first few times, understand the glossary, then do google search of FPV, UAV, watch FPV/UAV videos( there are tons of them in youtube). Basically in FPV , you still need to fly most of the time and in some cases it an do RTH( Return To Home) but that is pretty much FPV can do. UAV is much more than that.Those videos teach you more than any of us can tell you in few Pop Q & A.
Coming to question of why we need a Xbee or zigbee modem. these are two way data radios which are used to transfer information from/to the plane to/from the ground in digital format which then gets converted/displayed in dedicated software screen of your laptop that looks like display panel in regular small plane. The choice of having GCS is some times optional but mostly recommended. There are many other test softwares involved to test many things of UAV and your understandings of it. In the regular plane when pilot has no visual input( as in flying in the night or in the cloud) , he/she uses the instruments in the cockpit to understand the information required to fly the plane safely and to the destination. This is called IFR flying. Similarly , a UAV enthusiast/pilot likes to know/keep informed of his planes condition like speed, hight/altitude, temp, location, distance, location on the map, status of battery etc , so all this info is collected by special computer using many sensors and GPS which then uses a wireless radio to send this info to ground control station ( GCS) which UAV pilot uses to see / understand/ do R & D etc , without which there won't be much of interaction and learning or lessons learnt will be lost. Apart from this , the computer has enough intelligence to follow instructions( programed codes) and way points to cross in sky, go to destination, take pictures, come back to home location, loitor, wait, land automatically etc. This inteligence computer is called Autopilot and all the intelligence or most of it is taught/uploaded to it by the UAVpilot/programmer either on the ground or while flying( with the xbee like data modem). All this is explained in tons of easy to understand words in first page and elsewere in the forum and so you have to start from there. Read every bit of it( not before than :)) ), and come back with more question Good luck and cheers. Appo for typos....

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