Thursday, July 05, 2007

A Quick update...

Due to some scheduling issues we will not be testing this comming weekend, but we will be testing the weekend of the 14th.

Since the airlander flight testing did not go so well I thought I'd sneak up on the problem. I took my IMU, CPU, Telemetry radio and GPS and weighed it. I then took that much lead and put it on my Trex 450 RC helicopter. It's a small helicopter as RC helicopters go and I wanted to see if it could carry that much weight. So with 290 grams of lead it flew just fine, hovered for close to 5 minutes.

Step 2 Actually mount all that stuff to the helicopter and see if all works.
So I mounted the GPS, IMU, Telemetry Radio to the Helicopter. I then took the outputs from the RC receiver to the CPU board and then ran the helicopter servos from the CPU. The CPU is in the loop, but not yet doing anything but passing the commands directly from the RC receiver. I added an additional input from the RC receiver that I call mode that will allow me to switch from manual contol to automated control as time goes on. The GPS, RC receiver and telemetry radio all seem to coexist with no detectable interference.

I also did a fair bit of work on my telemetry display framework. My windows coding is a bit rusty so that has been an interesting challenge. So I flew it in my driveway, everything worked perfectly but my thumbs. I've been flying the copter in my driveway for awhile, but my wife added a new shrub........In any case I need to get new blades at the hobby store as I cliped the edge of the shrub and this pulled the helicopter into the shrub. None of the electronics or expensive bits seems to be damaged, just the typical helicopter crash parts, blades, flybar etc...
I'll get the replacement parts on Friday and go to a large open field and start doing some serious testing this week end.

I recorded the telemetry during this whole flight.
You can take a look at it I've uploaded the telemetry data file and the executable to view it.
The executable is the same one that shows telemetry in real time so on startup you need to select the "replay log" button. Then load flight2.dat. The log file has a bit of dull data as I go from starting the recording to connecting the RC power battery and moving the helicopter into position. Liftoff is around frame 8000. You probably want to click the 10X button until data starts changing. The 5 combo boxes on top left control what data is displayed.
The screen shot on the left is centered at the moment of shrub acquisition.
The derived Roll, Pitch and Yaw seem really reasonable, the rates and accelerations seem really noisy. Enjoy following along.

As always its probably not a good idea to download and run an executable from someone you don't know without virus scanning it etc... This exe was done for me on my computers so if there is a missing DLL, it crashes etc... no guarantee....

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