Following on with Chris' humerous submission today, and the bit of storytelling we have been enjoying in recent blog posts, I figured I'd post my latest tale of woe. Hopefully you will find it entertaining!
So, this past Saturday I competed in the SparkFun Autonomous Vehicle Competition using an ArduPilot with 2.6 firmware and ArduIMU. My airframe was the SkyFun from HobbyCity.
A few days before the competition SparkFun sent out an email saying I must submit a "team name". At the time I was in a bit of a panic because I was rebuilding my UAV from a crash suffered a few days earlier. While working on autonomous landing I discovered I had not planned my final waypoint very well and hit a pine tree. So, I told SparkFun that I was Team Death by Pine Tree! I glued the 2 halves of the fuselage together and continued on.
Friday, Ryan Beall was in town and we were sitting around and just couldn't stop ourselveds from trying to make 1 FINAL IMPROVEMENT.... I was not entirely happy with my altitude hold. It was tight enough for regular flying around, but not as tight as I wanted for doing auto landings. Ryan said (see how I try to give him part of the blame ;) ) lets just work through the math and see if the gain values make sense. So we did - and concluded the gain on the altitude error was way to low. We boosted it by a factor of 20. Does something smell fishy here. Of course when I worked through the math I forgot that I should be using altitude error in centimeters, not meters, so we had made the gain far too high. This caused a huge pitch oscillation that ended in a very spectacular sounding crash into a Maple tree. Time to call SparkFun and change the team name? Team Death by Maple Tree? This time the airframe was too far gone so I pulled all the electronics out and put them in my backup SkyFun.
Saturday was the big day. My UAV was flying great, with the fastest lap times by far, but I was too chicken to try auto landing the first 2 rounds. The final round came and I figured it was now or never. Mentally prepared for whatever auto land might bring out I saw my UAV inexplicably ignore the bits of code telling it to slow down at waypoint 9 and cut the throttle at waypoint 16. Instead it just kept ripping around and starting over at waypoint 1. SparkFun had assigned a 15 second deduction for auto landing and a 30 second deduction for auto landing with the UAV coming to rest inside a roughly 10 by 20 meter area. I asked the judge standing next to me "If I do nothing and the UAV arrives on the ground, then that is an auto landing and good for 15 seconds, right?" He looked a bit perplexed and said "well, yeah...". OK I thought, low voltage cut-off here we come. And a few minutes later it did come, followed by a nice little crash into an adjacent parking lot. The SparkFun band picked up on that immediately and began singing about Death by QualComm Parking Lot. On Monday I glued the 4 pieces of the fuselage back together.
Peter Hollands has been stuck here in Colorado since the SparkFun competition due to the Iceland volcano eruption and cancelled flights. He emailed me about getting together and I told him that today I would be taking the UAV to show to the local high school robotics club. He was quite happy to come along. We met a great group of kids and had fun talking with them about all kinds of robotics and UAVs and Arduino stuff, etc. Then we went outside for a demonstration. The high school has a lot of athletic fields, but the track team was using the football field, the soccer fields were all in use, as were 2 of the 3 baseball diamonds. With only 1 choice we headed to the open baseball diamond. I looked it over and said I was a bit nervous about the poles and fences so I told the kids they would have to settle for manual take-off and landing. But we had a pretty good demonstation. Then it was time to land. The first pass it was apparent early that I would float too far and hit the outfield fence, so I went around. The second pass was better, but still too high. For the third pass I figured I would come in nice and low over the outfield fence on the first base side and head towards the other corner of the outfield. All I had to do was steer around the foul line pole. Peter said "your going to hit the pole". "No," I said, "I see it". Then whack!
Tomorrow I will glue the pieces together again......
Team "Death by Foul Line Pole" just doesn't sound quite right.
