Does the magni motors have encoders?

General Questions
#1

So I am considering using a GPS module for navigating the magni, however, from what I understand is the accuracy of the GPS modules which are provided are not very accurate. Thus I need to introduce some correction factors to the process.

I am using OpenCV for lane detection, for the magni to stay on the specified path, and using GPS for guiding the system through the waypoints. However, I was wondering if encoders were present, so I would monitor the wheel movement and ensure it does not stray off the path.

Sidenote:
I was also considering using a magnetometer along with the GPS module, but that would be too many peripherals…

Thanks!

#2

Yes we have wheel encoders. The position of the robot using the wheel encoders alone is published to /odom by default. We check this for each release by the way.

Wheel encoder position is ok for short term resolution of base_link orientation (robot pose) so it is advised to use both GPS and /odom combined using either a kalman filter or other less involved approach.

As far as Magnetometer, the results of a great many robot makers is that magnetometer is greatly effected by local and nearby metals ‘warping’ the B field of or very small signal we get for Earth magnetics. Many people experiment with placing the magnetometer on a post about at least a foot above the robot and so on but if you drive near an iron car or fence be aware that that warps the B field of the earth in often significant ways.

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