CMPS14 Compass

Settings - Data Sources then you need to turn on heading correction from auto steer, same for roll.

Heading=from auto steer, roll=from auto steer. was set to. IMG_0648

What AOG is that?

Yes AOG. (new icon)
https://github.com/Vilicat-cat/AoG-New-Icon

Tag him / ask, he might have modified the display for GPS & IMU heading?

When I uploaded the original AOG, the problem was fixed, thank you.gf

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Ive made a little CMPS14 Enclosure with a Mount for an Rj45 Port.
The idea is to glue in the cmps 14 in the direction you like, and mount it inside your cab.

IMG_20210322_221613
IMG_20210322_221527
IMG_20210322_221553
The back fits nicely and can be glued in, i did use the rj45 Port mostly due to its small size and because i had one laying around.
If someone is interested in the Fusion or STL files i can upload them.

3 Likes

Nice work, have you used pca9615?

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No, just a Rj45 port mostly because the pca9615 Module from Sparkfun is not available in Germany, and that now since 2 weeks.
Even though my cable is one Meter long itā€™s not a Problem with the I2C Bus.

1 meter is quite good value, I have read that better performance will be obtained with CAT6 ethernet cable, one cable pair each for SCL and 5V and one cable pair for SDA and 0V
for network cables
this prevents the two signals from interfering with each other.
maybe p82b715 you can do it yourself.

Against my habits Iā€™ve actually read the whole thread before replying :grin:, so please correct me if Iā€™m totally off in the conclusions I made:

  • CMPS14 always using the magnetometer, need to take care of placement to avoid disturbances, gets true north heading
  • BNO08x can be set up to work in exactly the same manner as CMPS14 if desired
  • Autocalibration of the magnetometer is whatā€™s partially causing the jumps
  • If using the magnetometer, usually better to place the sensor somewhere not close to iron and/or electronics
  • BNO08x in game vector mode is just a 6DOF MEMS sensor, no magnetic interference so shouldnā€™t really matter where you place it
  • Currently thereā€™s no big benefit in the AOG data fusion algorithm in having the true heading

Additional thing that Iā€™d like to experiment with is a BNO08x based WAS, there weā€™d need the magnetometer unless weā€™d utilize the kinematic constraints of the axle / tractor geometry. But Iā€™d guess you need to compensate for the gyro drift somehow in any caseā€¦

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That pretty much sums it up as far as I can see, and a CMPS14 is twice the price of a BNO085.

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I have installed the CMPS14 directly in the autosteer box, connected with jumper cables to the MMA socket - works fine!

Hello,

Yes good summary !
For your last question, goog question, Iā€™m not sure. You want to put a BNO on the wheel, one on the tractor, compare heading between and calculate steer angle ?

Math

Looking at the stability and sensitivity of the BNO085ā€™s output, even at very small steer angles at very low speed, I wondered if the angular velocity output could be used vs speed to give a reasonably stable steer angle?

Two options, I guess. Either use the heading information from both IMUs and look at the difference, but this is quite calibration sensitive. Or then use both in game vector mode and just use the rate gyros, but then you gotta do the zeroing somehow in any case.

Trimble(?) has such a commercial system, someone had the link here to another forum where it had been torn apart and it was just a single rate gyro inside. So itā€™s just comparing the gyro on top of kingpin to the one in the autosteer box with coninciding axis.

With more DOFs you should be able to better compensate for front axle oscillations etc.

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Realistically, I think if something is going to be mounted at the axle it might as well be an angle sensor. Drift and tolerances will be a huge problem with IMUā€™s used in this manner I would think.

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Probably a stupid question, but how can i enable detection of forward/reverse?
I want to try cmps14 and the value at IMU looks fine, but when i reverse the arrow (tractor) on the screen turns around instead of reversing. Also the button for manual change of direction doesnā€™t light up. In data source heading is from autosteer. Iā€™m clearly missing something.

Only wait a 4.63 Beta Release :wink: :wink:

Hello, can the different parts for cmps14 simply be copied int the UDP Autosteer ino? To use it with Ethernet,
Regards, Peter