Comment by Ios on September 30, 2008 at 1:43am

There were about 4 teams in the search and rescue challenge. QUT was up first with a very large aircraft, however their radio link failed and the aircraft went into failsafe, completely destroying it. Up next was team 'Missouri', but they were having some engine troubles, so decided to go after the only other team - Telemasters. They had a very nice 'Senior Telemaster' which had been converted to electric power, however when they got up their radio link also failed, and so their aircraft went into failsafe and crashed, but it was a soft crash and the aircraft was fine. Telemasters and Missouri later descided to have another go at the mission.

Team Telemasters had a unique mission plan. As their aircraft was powered by an electric motor, they were going to fly out to the search area, locate Outback Joe, fly back and land, change the batteries, and then fly back and drop the package to Joe.

There seemed to be quite a lot of radio interference. Two search and rescue teams went down due to it, and many of the crashes in the Airborne Delivery Challenge were due to radio problems. It seemed like half of the teams that came to the competition left without a plane intact. There were also quite a few helicopters, but they were small and had a hard time dealing with the wind (consistent 10-15 knots), and every helicopter in the airborne delivery challenge crashed. Unfortunately, no-one brought a scanner or oscilloscope which would have allowed measurment of the amount of radio activity on certain frequencies.

There were a lot of devices that could have been causing radio interference, such as wireless microphones and video cameras used by the organisers and news crews, but there was also a giant LED TV used to show ads throughout the event. It is unknown if that was effecting anything, but anything is possible.
Of course, there is also the possibility that there was someone near the airfield purposely 'shooting' down UAVs, but this isn't very likely. There was nothing official said about radio interference.


At the competition, there was quite a bit of talk from the organisers that led some people to believe that it may not be on next year, and will probably only be held every second year. This is just due to the amount of organisation required for such an competition.

3D Robotics Comment by Chris Anderson on September 30, 2008 at 7:20am

Fascinating update--many thanks. We you on one of the teams competing? And were the teams with radio problems on using 2.4Hz digital radios or just 72 Mhz?

Comment by Ios on September 30, 2008 at 1:30pm

I'm actually with one of the teams which did not compete in the Search & Rescue Challenge. I intend to detail our entry on my blog here on DIY Drones in the next couple of days - I've already posted a couple of photos.

One of the Airborne Delivery Challenge teams using a Paparazzi autopilot which requires a PPM receiver, went out for the test flight and was having so much glitching that they had almost no control, even from only a few feet away. . They switched to a PCM S receiver, which was okay, but this meant they couldn't use their autopilot. Even the people using Spektrum 2.4GHz RC radios were having severe problems, and there were so many different airframes that the cause would not have been airframe or equipment layout related...

For you interest, there is another UAV challenge in South Australia, called Genesis UAV Challenge for high schools, similar to the Airborne Delivery Challenge.

Comment by Rory Paul on September 30, 2008 at 3:30pm

What was the distance that had to be flown to the rescue victim?

Comment by AD on September 30, 2008 at 4:58pm

G'day all,
Aaron Donaldson here. One half of Team Telemasters.
for our documentary entered into the UAV Challenge.

Great competition and well worth all the effort to get there.

Our UAV is a 30 year old Senior Telemaster airframe converted to electric. My Dad built two of these when I was a year old and myself and Simeon resurrected them to use in the Challenge. I live in Geelong VIC and Simeon lives in Toowoomba QLD (About 1800 kms apart) Having two similar airframes meant we could both test the systems and we would have a spare frame for the comp.

Our plane flew perfectly during the test day (Tuesday) and completed the first fully autonomous circuit at the competition (in the two years it's been run). We are using a UNAV 3500FW and it performed perfectly. A big thanks to Mark at UNAV for his help and assistance in the AP setup. Nothing was too much trouble.

On the day of the competition (Wed) the QUT team suffered a crash during a flight demonstration to qualify to compete in the Search and Rescue Challenge. I spoke to members of the team afterwards and they believe (without fully studying it) the failure was due to power loss to their AP system causing a reset and loss of communication. Their system doesn't arm until satellites are acquired so a power loss means around a 30 second reboot. On viewing footage of the failure they didn't think that their failsafe had activated due to the position of the control surfaces not moving to the correct pre set positions. (all of this is just info gathered from talking with members of the team and may not be real cause anyway :)

Our aircraft was capable of completing the mission but due to operator error in the calibration process (our two team members live 1800 kms apart and have had no time to practice a full run and setup for the mission) and our standard operating procedures having not been set before the day. After attempting to start the mission the aircraft was seeking an incorrect altitude so we landed to check our systems. All seemed okay so we attempted again. On climb out we the aircraft went into failsafe mode and terminated the flight. Our safety system works on a heartbeat pulse being received by system onboard the aircraft and when it doesn't get the pulse, after 7 seconds the servos move to a pre set position and the throttle stops. Our UAV descended in a circling manner and landed on the airfield. The tail, prop and undercarriage were damaged and we couldn't repair it and reattempt in the time left available to us.
On removing the wing I noticed that the main flight batteries had shifted in flight and unplugged a power connector for the radio modem that is mounted in the wing. Having lost the power to the modem our safety system didn't receive the pulse and it went into failsafe mode overriding RC commands. Just as it was designed to do and just as the organisers wanted too.
The Missouri S&T team, also using a Senior Telemaster, suffered damage to their UAV due to pilot error on take off. A bit of bad luck for them after a lot of work. They had a great setup and would have made it into the search area for sure.

So all up two aircraft failed due to procedures and or operator error and the third was an equipment failure (yet TBC)

The search area is approx. 5 SQ Kms and is located 2.5 kms from the end of the Kingaroy Airfield.
www.uavoutbackchallenge.com.au for all the info on the challenge.

Oh and I wasn't really happy with the way the reporter quoted me too. She paraphrased a fair bit. It makes us sound like we are not that bright and gloating that the other teams were no good. Not the case at all. The other teams were both brilliant and all were great entries and great people. There was a camaraderie between the teams and plenty of ideas, tools, and advice were shared during the three days. I was devastated when I saw both the other teams suffer damage to their UAVs as I know how much work goes into them.

So as a wrap up we had a great time, learnt a lot, and will be back next year bigger and better.

Cheers
Aaron
Team Telemasters

Comment by AD on September 30, 2008 at 5:00pm

www.ausuav.com

Link didn't work in the post above.

You can see our entry for the Documentary section of the Challenge here.

Comment by Genesis Factor on September 30, 2008 at 5:06pm

awesome job, AD!!!

I still don't get why the planes all failed like that though. If they were autonomous, why would a radio uplink matter?

Comment by Rory Paul on September 30, 2008 at 7:20pm

Autopilots can have an RC signal loss feature. Once signal is lost they can be programmed to perform a procedure (return to way point 0). If the takeoff spot was 2.5kms from the 5kms square search area it could place the UAV out of signal range and trigger the signal loss procedure. I cannot believe however that this was employed incorrectly by the teams. QUT was running a MicroPilot autopilot and the feature is documented and does not have to b e employed. Very strange....

Comment by AD on October 1, 2008 at 12:27am

Hey Genesis, Thanks!

In answer to why a radio uplink matters........

The organisers wanted, as part of the challenge, that the UAV was to be in contact with the ground station at all times. To do this it needed to receive a heart beat or pulse. The UNAV 3500 is designed to be flown out of RC range and return back to RC range for landing. We had the rules and developed a system that was simple and worked.... we proved that in the competition :)

Our safety system was the last step before the servos and was a timing circuit re-set by receiving a pulse. The pulse was sent from the groundstation and received by the radio modem onboard. This gave us an effective range of communication of more than 15 kms, well outside any standard RC range. Our UAV was launched on standard RC gear then switched into autonomous mode and flown out of RC range. The failsafe on the RC reveiver is set to default to AP mode so if it does go out of RC range then control is handed to the AP and it will fly to the next waypoint , or we can comand it to come home using the laptop. The safety system is the last step in the chain so that if RC signal and modem communication is lost then it will overide everything and enter failsafe mode. We lost power to the onboard modem, the pulse wasn't received to re-set the timer, and the UAV went into failsafe mode. You are right Condor and we could have had a failsafe that would return the UAV home but that's not what the rules were. If we lost modem comms then the failsafe could be waypoint 64 (Return home) and landed using the RC control.

Hope that explains a bit.

Cheers
Aaron

Comment by Genesis Factor on October 1, 2008 at 4:45am

it does...but it kills me that people lost power or signal like that. I'm sorry about your failure though. To be honest, i haven't flown in 15 knot winds, except in my sim, and looking at everyone, it must be tough. All i remeber was in the high wind, high thermals, i got as much air as i could on takeoff. was ther a hieght requirement?

Maybe that was a secret part of the competition (the signal lost)?

You guys though, no practice runs. i am impressed. Good man. Men. Whatever;). I wish i could hit Australia for the next comp. I need to read the rules.

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