Auto takeoff / Mission Planner

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1

HI All

I am hoping I can get some clarity on this matter. I am not entirely sure where to post this as it is a Mission Planner/Arduplane/Firmware issue!

I have a a Skywalker frame(similar setup to the Aero-M) with a Pixhawk (3.3.0) that we use for aerial mapping. We have built a few of these platforms and they all work really great. We use auto takeoff and auto landing and have never had any issues for over 100 hours with exception of man made mistakes such as installing the prop the wrong way!

We recently handed one over to a client for a mapping mission. He asked for assistance with flight planning as he wanted to fly 2 areas within the same mission without landing. Having done this type of flight planning using the survey tool in Mission Planner fairly often, I helped him out.

The takeoff was not successful and the plane had a hard landing 100m away. From an analysis of the logs, it appears that the Pixhawk was armed with more than 20 degree roll. This error was pointed out by a few experts as a big no no as Pixhawk only can cope with a few degrees of roll upon initializing.

My concern is that in the first line of the mission waypoints, under takeoff, the pitch is “0”. I think this came about as I last had an Iris multirotor connected to Mission Planner. Would having “0” as a pitch value cause the auto takeoff to fail? Or does TECS override this? My only option is to manually try this out for myself but I am in no mood to bust a plane!

Attached below are the logs. I would greatly appreciate any feedback.

dropbox.com/s/hbvfxt8ppazj2 … s.zip?dl=0

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There should be no problem with arming the Pixhawk while not level. It is advisable to keep the plane still while booting up the board, but once the accelerometer calibration is complete, you don’t need to be concerned with the attitude. Nothing happens during the arming process in ArduPlane that could affect IMU calibration.
If you have an airspeed sensor, then the plane should pitch up to maintain its trim speed, if it can fly far enough at 0 pitch to accelerate before hitting something. I generally use a low number like 15 degrees to allow the plane to accelerate before climbing at a steeper gradient. If you have no airspeed sensor, the Takeoff pitch angle is critical as it will be followed during the entire takeoff. This could cause a crash if set to 0. Sorry I didn’t look at your logs, I’m on my phone.

3

Thanks for the reply. No airspeed sensor has been used.

4

Luke,

iskess is spot on. I extracted the WP and the takeoff pitch was set to 0 degrees.

Pitch angle is the first box next to the command Takeoff if you pull up the green Waypoints window in the Flight Data screen.