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Permalink Reply by Anant Rao on March 18, 2012 at 2:26pm

Was a silly mistake......i was doing it without a GPS lock.....now i can change mode to AUTO....

But the throttle problem remains....max throttle tht i get with RC channel 3 (max,min = 1885,1100) and sim throttle gain of 10000 are 0.180, which makes sense.....so i change throttle gain to 3000, and quad takes off fine with mission script (new throttle in XPlane = 1885/3000 = 0.628)....

However, whenever it encounters mode change command to AUTO in mission script, it just keeps coming down, until it crashes.....throttle value show the same (no reduction) in mission planner and XPlane....i've tried them with different home altitudes with only one command in AUTO mission: takeoff to certain altitude....but same thing happens always....the usual waypoint nav too responds the same...

Any suggestions or ideas on what am I doing wrong here....??

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Permalink Reply by Karl Lehenbauer on June 3, 2012 at 6:54am

Hi Anant...  I too am in about the same place simulating in X-plane.  The throttle values sent range from about .112 to .186 which is insufficient to get the simulated quadcopter to take off.  Messing with throttle gain like you did or editing the plane in x-plane to scale up the thrust value or increase the horsepower works, but since the minimum value is .112 rather than 0, the minimum throttle value gets scaled up as well, so when trying to fly the sim with the radio, you throttle all the way down and there's still a lot of thrust.

I don't see any way to get x-plane or the mission planner, through their interfaces, to subtract an offset before applying scaling.

My theory is that the servo pulse width times that ardupilot would use to set the motor controllers are being sent to xplane rather than a percentage of total thrust, so the .110 to .185 is ardupilot asking for 0 to nearly 100% thrust, but the motor controller settings are instead being interpreted as 11% to 18% thrust.

If I'm right then either the HIL simulation version of the Ardupilot software needs to be modified to perform this scaling, or the ground station software that's making the UDP packets needs to do it.

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Permalink Reply by Anant Rao on June 3, 2012 at 4:35pm

I got this working 1 month ago........here's the link to latest post......

http://diydrones.com/forum/topics/xplane-simulation-keeps-crashing-...

Hope it helps.....

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