Flow Deck V2 Not Stable

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cboustead
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Flow Deck V2 Not Stable

Post by cboustead » Sun Apr 07, 2019 5:22 pm

I have attached a Flow Deck V2 to my CF2 and created a simple program that would command the CF2 to rise to 0.6 m and hold for 20 seconds. When executed, the CF2 follows the command but the altitude variance is very high, often flying out of control. The CF2 appears to drop suddenly and tries to regain control. Also, when executing from the cfclient in 'hold' mode, the issue is still present and, as far as I can see, the distance data received has no issues.

Here is a video of the flight: https://www.youtube.com/watch?v=B3mJA9h ... e=youtu.be



tobias
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Re: Flow Deck V2 Not Stable

Post by tobias » Mon Apr 08, 2019 1:46 pm

The CF2 in the video does not fly as is should. You say that the distance data looks OK, you don't see any "outliers"? What firmware are you running? Is it the same on a lower height, like 0.3m?

cboustead
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Re: Flow Deck V2 Not Stable

Post by cboustead » Mon Apr 08, 2019 1:51 pm

The distance data looks okay as far as I can see but that's only when I monitor the single value that is provided in the cfclient. It could be that there are anomalies that are not displayed. At 0.2m the CF2 is semi-stable, it only fluctuates a little. At 1.0m the CF2 fluctuates a lot and quickly flies out of control.

tobias
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Re: Flow Deck V2 Not Stable

Post by tobias » Mon Apr 08, 2019 2:24 pm

Could you try plotting the value in the plotter tab by creating a log block with the log variable range.zrange and logging interval 10ms. There you should be able to see all sensor values.

My guess is that the laser ranger sensor VL53L1 is badly soldered and does not have enough "energy/light" to work well at a longer range. This should be verifiable with the plotting above.

cboustead
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Re: Flow Deck V2 Not Stable

Post by cboustead » Mon Apr 08, 2019 3:06 pm

Are you able to provide me will a little more guidance on how to do this?

tobias
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Re: Flow Deck V2 Not Stable

Post by tobias » Tue Apr 09, 2019 7:18 am

I see now that it is not completely documented but the plotter is abailible as a tab in the cfclient. To setup log configurations, while connected go to "settings->logging configurations". Then find the log variable range->zrange and mark it. Press right arrow to put it in a block configuration. Fill in logging period 10ms and then save it with an appropriate name. Then go to the plotter tab and open the configuration you saved. You should now see the distance plotted. :D

cboustead
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Re: Flow Deck V2 Not Stable

Post by cboustead » Tue Apr 09, 2019 8:54 am

The zranger appears to be logging the correct values for flight.

When I try to fly the CF2 it flies up and down rapidly, hitting the floor on most occasions. This makes it hard to determine if there are any anomalies because the CF2 is changing height so often.

To overcome this, I held the CF2 and lifted it manually to plot the values. I did this with thrust on to ensure the battery was under load. You can see the results in the attached image. As you can see, there are no obvious anomalies.

I also monitored the plot with a lower sample rate so I could try and see any anomalies that might not show up in the longer plot, again, there were no obvious anomalies.

I was thinking it could be a power issue but when I fly the CF2 using an xbox controller without the hover mode there aren't any issues

cboustead
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Re: Flow Deck V2 Not Stable

Post by cboustead » Tue Apr 09, 2019 9:00 am

cf1 - Experiment where I manually changed the height by picking up the CF2 with thrust on.
cf2 - Experiment where I tried to fly the cf2 in hover mode. CF2 changes height.
cf3 - CF2 stationary on floor. There are some drops here but they are not drastic.
Attachments
cf3.png
cf2.png
cf1.png

cboustead
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Re: Flow Deck V2 Not Stable

Post by cboustead » Tue Apr 09, 2019 9:16 am

I remembered that the issue is magnified when the CF2 is at higher altitudes.

I simply held the CF2 at a height of 30cm, with zero thrust, and this was my output.

Looks like the issue is with the zranger after all...
Attachments
Screenshot 2019-04-09 at 10.14.48.png

tobias
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Re: Flow Deck V2 Not Stable

Post by tobias » Tue Apr 09, 2019 11:39 am

Yep, that looks like a problem with the zranger. We will arrange a replacement.

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