Bump detection with landing WPs

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Bump detection with landing WPs

Postby LPR » Tue Nov 10, 2015 4:37 pm

I found that bump detection with a landing WPs can be a problem. My 4.5 kg quad can fly over 25 m/s so I have been flying at 20 m/s and seeing good results.

Yesterday I was surprised by seeing all the props stop when the quad was 25 meters above the ground. I was very lucky to have soft ground for the quad to crash in so only two landing gear needed to be replaced.

Looking at the log, now I see that I got over 1.5 g on the Z axis while slowing from 20 m/s.

Having a mission setup to go from 20 m/s to a landing WP is a big problem. From now on I'll always slow the quad down to 5 m/s before using a landing WP. Adding 5 seconds of loiter to the WP before the landing WP would help.

From now on I plan not to use a landing WP no higher than 4 meters above the ground.

Larry
Last edited by LPR on Tue Nov 10, 2015 10:34 pm, edited 2 times in total.
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Re: Bump detection with landing WPs

Postby sandmen » Tue Nov 10, 2015 5:15 pm

Hmm, don't know, which AQ FW version you have.
But I don't think, that there is a "Bump" detection.
Didn't looked in all code versions, but Bill has removed that some time ago :-)
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Re: Bump detection with landing WPs

Postby bn999 » Tue Nov 10, 2015 6:29 pm

There has been no bump detection for a long while. During landing, the system continues to ramp down throttle until it hits a minimum threshold and disarms.
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Re: Bump detection with landing WPs

Postby LPR » Tue Nov 10, 2015 7:31 pm

Bill and Peter

That's good to know but it still looks like the FC thought it had landed and it turned off the motors. Here's the part of the mission log where the crash happened.

I'm using the latest Quatos FW for the M4.
Attachments
171-AQL - Copy.LOG
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Re: Bump detection with landing WPs

Postby LPR » Tue Nov 10, 2015 9:57 pm

Here's the message log attached and the complete log of the mission.

https://www.dropbox.com/s/0xv8nvtxm2uue ... L.LOG?dl=0

Larry
Attachments
171-MSG landing WP crash.LOG
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Re: Bump detection with landing WPs

Postby LPR » Wed Nov 11, 2015 11:06 pm

I should have posted the mission that I was flying. The mission is attached. I used 20 m for the radius of influence for all of the WPs and that may have been part of the problem with the landing WP.

There's no doubt that I was pushing the limits of a reasonable mission. I'm just trying to find the fastest way to do a photo mission for a farm field. There's no doubt that I found a real fast way to land. :D

Larry
Attachments
aq HOME 160.txt
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Last edited by LPR on Wed Dec 09, 2015 10:04 pm, edited 2 times in total.
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Re: Bump detection with landing WPs

Postby chschmid » Wed Nov 11, 2015 11:16 pm

There's no doubt that i found a real fast way to land. :D


I like your humour Larry.
20m/s is quite fast. We were flying 15m/s lately and its already fast. We crashed when we were trying to do the 10m helix at this speed.

Cheers
Christof
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Re: Bump detection with landing WPs

Postby LPR » Thu Nov 12, 2015 12:33 am

Christof

There's no doubt that speed will offer us a number of ways to crash. I think that having motors turn off is the most civilized way to crash.

A 10 meter Helix would be very hard to do at 15 m/s. I would not think you would have enough tilt for that tight of turns at 15 m/s.

Larry
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Re: Bump detection with landing WPs

Postby srinath » Sat Nov 14, 2015 4:24 am

chschmid wrote:
There's no doubt that i found a real fast way to land. :D


I like your humour Larry.
20m/s is quite fast. We were flying 15m/s lately and its already fast. We crashed when we were trying to do the 10m helix at this speed.

Cheers
Christof


A 15 m/s flight around a helix wound involve a bank angle of 66 degrees and a huge pitch angle to overcome drag. There is no way you will have enough thrust to stay in the air.
The equivalent would be going up a hair pin bend at top speed and never taking your foot of the gas. You will fly off the mountain no matter what traction control you use :)
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Re: Bump detection with landing WPs

Postby srinath » Sat Nov 14, 2015 4:25 am

LPR wrote:I should have posted the mission that I was flying. The mission is attached. I used 20 m for the radius of influence for all of the WPs and that may have been part of the problem with the landing WP.

There's no doubt that I was pushing the limits of a reasonable mission. I'm just trying the fastest way to do a photo mission for a farm field. There's no doubt that I found a real fast way to land. :D

Larry


I will run your waypoints on the HILS and see what happens. I could also simulate GPS outage if needed.
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