What dose the new orange cube buy us? Dose it stream mavlink mesages faster?

Brian_Duvall · February 29, 2020, 9:47pm

Hello all,
I currently running an original 3dr pixhawk with arduplane. when I read mavlink messages off the telem 2 ports and set the stream rate to 50 Hz the most I can get out is 5Hz. I am wondering if the cube orange with the faster processor would make any difference?

What I do not understand is if I use a original 3dr pixhawk and PX4 I get 50 Hz of mavlink mesages no problem.

I am useing the code in the link below to read messages with the rate set to 50.

gist.github.com

https://gist.github.com/vo/9331349

gistfile1.py

#!/usr/bin/env python

import sys, os
from optparse import OptionParser

# tell python where to find mavlink so we can import it
sys.path.append(os.path.join(os.path.dirname(os.path.realpath(__file__)), '../mavlink'))
from pymavlink import mavutil

def handle_heartbeat(msg):

This file has been truncated. show original

Thanks

yak-54 · February 29, 2020, 10:30pm

Well it like comparing a VW bug to Porsche 911
yes you will notices difference big time

Brian_Duvall · March 1, 2020, 3:02am

Thanks for the reply, I am more curious about how will the new cube effect how fast mavlink messages can be sent to a companion computer.

Also it looks like the orange is only for beta testing now. Is this true?

james_pattison · March 1, 2020, 4:40am

@peterbarker could probably give some advice about getting Mavlink throughput. 5Hz doesn’t sound right to me at all.

peterbarker · March 1, 2020, 5:04am

   I currently running an original 3dr pixhawk with arduplane. when I read > mavlink messages off the telem 2  ports and set the stream rate to 50 Hz the most I can get

Well… what’s on the other end of that telem2 port? What is its baudrate, and what sort of bandwidth are you expecting over that link?

out is 5Hz. I am wondering if the cube orange with the faster processor would make any difference?

It would allow you to push up the main loop rate and be sure you won’t get scheduling issues. One issue with pushing messages out is that we don’t allow enough time for the relevant functions to actually push the messages out - better to fly the plane than tell the pilot we’re going to crash. Setting SCHED_LOOPRATE to 300 is safe enough on a PixHawk (in general, anyway).

What I do not understand is if I use a original 3dr pixhawk and PX4 I get 50 Hz of mavlink mesages no problem.

50Hz of all messages is unlikely over a 900Hz radio, for example.

I am using the code in the link below to read messages with the rate set to 50.

Your Python there - good as it is - can be improved by specifying the rates on a per-message basis, rather than requesting an entire data stream. You’re after MAV_CMD_SET_MESSAGE_INTERVAL.

Brian_Duvall · March 13, 2020, 9:38pm

thanks for the reply peter,
I have an RPI connected to telem2 port. Buad 921600. I am ruining the same python code for both PX4 and Ardupilot. I will give the SCHED_LOOP_RATE a shot.

In other news i did buy a cube orange! With out changing anything other then the SR2 rate for Raw_sensors and RC_Channels I got 40 Hz IMU and 25 Hz for RC channels.

The next problem is now the servos twitch when I go to stabulize or FBWA or B

Is the tuning different? I have tried reducing the gains but the twitch is still there just at a lower amplitude.

Georacer · March 16, 2020, 2:17pm

@peterbarker, do you believe the same performance (50Hz MAVLink stream or higher) can be expected with message upload, e.g. RC_OVERRIDE?
Will these messages be accepted and processed?
Or there is a different mechanism onboard for message output vs message input?

For background information, since currently Dronekit supports only position and velocity reference passing, if one wants to do rate reference passing RC_OVERRIDE seems to be the only available “hack”.