Adding crazyflies about crazyswarm HOT 14 CLOSED

This could be either an issue with the communication (high packet drop rate) or an issue with tracking.

1. How did you determine channel 37 to be good? A nice tool is https://github.com/bitcraze/crazyflie-lib-python/blob/master/examples/radio-test.py.
2. Do you have the LED ring installed? It is color-coded and tells you if the communication is good (green) or bad (red).
3. Are all markers tracked correctly when you fly 3 or more? You could record the pointcloud topic and tf during the execution during a crash. A replay of those topics should allow you to see if the tracking is good at least before/at the beginning of the crash.

The original crazyflie_ros only works well with up to 2 CFs per radio, because the controller is running on the PC (rather the CF), and it doesn't use broadcasting commands.

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I determined the best channel using the tool that was specified. Unfortunately I do not have the led ring. I am adding 6 more cameras today to improve tracking and will try recording the data afterwards to see if the problem lays in tracking or communication. Also there sometimes seems to be a slight problem in the ICP from time to time where it calculates the position slightly incorrectly, or on original startup the orientation is calculated incorrectly. I am using 5 markers that are not placed symmetrically. Also I am using the same marker configuration for all the crazyflies but it seems the markers on a few of them are slightly off (not noticeably)(currently not using these for the current testing) and the ICP struggles to converge. What would be the best approach to this problem? Should I relax the ICP or define marker configurations for each one in the launch file?

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How do you know that the position is calculated incorrectly? On startup, we try several possible orientations (https://github.com/USC-ACTLab/libobjecttracker/blob/master/src/object_tracker.cpp#L186) and take the best one. You can try increasing that number and see if that improves your tracking. We only use four markers and have no such problems.

It is expected that you can't place the markers perfectly identical. There is currently no full support for different marker configurations per CF (we are working on that though). You can try adjusting the fitness score (which is the sum of the error squared between measured marker position and expected marker position based on the current transformation): https://github.com/USC-ACTLab/crazyswarm/blob/master/ros_ws/src/crazyswarm/launch/hover_swarm.launch#L82. Naturally, this number needs to be higher if you use 5 instead of 4 markers.

You could also try the marker configuration that works well for us. You can find a picture showing the markers in J. A. Preiss*, W. Hönig*, G. S. Sukhatme, and N. Ayanian. "Crazyswarm: A Large Nano-Quadcopter Swarm", in Proc. IEEE International Conference on Robotics and Automation, Singapore, 2017, Figure 1 (preprint available at http://act.usc.edu/publications.html). We use 7.9mm spherical markers, although that depends on your motion capture system.

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What would be the best way to change the channel on a crazyflie on the crazyswarm firmware?

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Connect your CF over USB and change it using the Bitcraze Python Client.

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So just an update, I got multiple crazy flies working now. After fixing the tracking issue there seem to be crazyflie specific problems. Not sure if its due to propellers coming loose or motors, but I was able to find 4 that were able to execute the figure eight with my marker configuration, proving that there is no communication or tracking issue left. Closing this now.

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Hi, @whoenig , @itzzartem

I am trying to use radio-test.py
However, I got the error messages as shown in the following.

~/crazyflie-lib-python$ sudo python examples/radio-test.py 
Traceback (most recent call last):
  File "examples/radio-test.py", line 19, in <module>
    import cflib.drivers.crazyradio as crazyradio
ImportError: No module named cflib.drivers.crazyradio

Could you teach me how to use radio-test.py ?

Thank you in advance

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You have to install the CF python lib on your system:

$ cd crazyflie-lib-python
$ pip3 install --user -e .

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It works!
I appreciate it!

However, I cannot see any suggested channels....
Do you think the following output is correct?

~/crazyflie-lib-python$ python examples/radio-test.py 
/usr/lib/python2.7/dist-packages/numpy/core/_methods.py:59: RuntimeWarning: Mean of empty slice.
  warnings.warn("Mean of empty slice.", RuntimeWarning)
/usr/lib/python2.7/dist-packages/numpy/core/_methods.py:70: RuntimeWarning: invalid value encountered in double_scalars
  ret = ret.dtype.type(ret / rcount)
/usr/lib/python2.7/dist-packages/numpy/core/_methods.py:82: RuntimeWarning: Degrees of freedom <= 0 for slice
  warnings.warn("Degrees of freedom <= 0 for slice", RuntimeWarning)
/usr/lib/python2.7/dist-packages/numpy/core/_methods.py:94: RuntimeWarning: invalid value encountered in true_divide
  arrmean, rcount, out=arrmean, casting='unsafe', subok=False)
/usr/lib/python2.7/dist-packages/numpy/core/_methods.py:116: RuntimeWarning: invalid value encountered in double_scalars
  ret = ret.dtype.type(ret / rcount)
('Channel', 0, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 1, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 2, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 3, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 4, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 5, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 6, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 7, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 8, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 9, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 10, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
.
.
.
('Channel', 120, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 121, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 122, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 123, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 124, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)
('Channel', 125, 'ack_rate:', 0, 'rssi average:', nan, 'rssi std:', nan)

Suggested Channels:

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Hi @whoenig ,
do you have any idea about it?

Thank you in advance..

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@srnetsr
That is an incorrect output. Seems like your not actually connected to the crazyflie. Where is the crazyflie when you are running this test? I found that if I started the script with the crazyflie in our fly zone it would give me the output you are getting. If I started it with the crazyflie close to the dongle and then placed it in the fly zone, I got the correct results. Also you could just look at a high frequency analyzer for a more accurate result. You could also get a wifi analysis app and see what wifi channels are being used around you. If you take that approach, wifi channel spacing is much wider than the crazyflie channels so you will have to make the conversion. i.e wifi channel 6 is channel 37 for the crazyflie. Also wifi routers tend to hop channels to find one with least traffic so try to choose one that isn't getting any traffic or is between channels if possible. Don't forget that depending on where you are located, not all channels are legal. In the US, FCC regulations do not allow operation past 2.4835GHz , i.e channel 83.

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@itzzartem , thank you for your reply.
But it does not work still. I got the same error.
I flashed nrf and stm into Crazyflie and flashed firmware into CrazyRadio by following http://crazyswarm.readthedocs.io/en/latest/usage.html.
Is it the same environment to yours?

@whoenig , I have a question.
I found bitcraze/crazyflie-lib-python#21
I followed http://crazyswarm.readthedocs.io/en/latest/usage.html, and flash nrf & stm using your instruction.
The question is that what is the difference between https://github.com/bitcraze/crazyflie2-nrf-firmware and cf2_nrf.bin file in crazyswarm/prebuilt ?

Thank you.

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There is no difference - the NRF51 firmware is identical to the latest official one. The prebuilt binary is only there for simplified reproducibility.

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Thanks for confirmation, @whoenig
Based on bitcraze/crazyflie-lib-python#21 and information you gave, I tested all cases, and finally what is the problem.
The problem is related with the address of cf2.
I set the address of cf2 as 0xE7E7E7E701.
This address does not work!
I switched it to 0xE7E7E7E7E7, and it worked.

I cannot see any information about address in radio-test.py file, can you find any part for modification?

Thank you guys, though!

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