I documented the first test fixture I built for moteus some time ago. As the shipment volumes have gone up, the fixture became something of a limitation, and also was a little problematic in a few ways.

The old “state of the art”

First, it relied on attaching 3 connectors by hand for each test, which was a decent fraction of the cycle time. Second, the pogo pins it used were non-replaceable, and also connected only to the debug phase wire test vias, which were tiny. They wore out relatively quickly, and replacing them required building a whole new board. Finally, since the pogo pins were PCB mounted, a PCB needed to be printed for any change in the pin locations or which pins to probe.

It has been on github for a few days now, but I’m excited to announce the newest moteus firmware release, 2022-07-11. This release includes some big features, and some quality of life improvements all around.

• Flexible I/O subsystem: This release includes the new flexible I/O subsystem. This adds support for many new encoder types and lets you connect them up in a wide variety of ways.
• Cogging torque compensation: Preliminary support for cogging torque compensation is present in this release. It works pretty well on a number of motor types already, future articles will describe it in more detail.
• Encoder eccentricity compensation: This feature lets you linearize the output position and velocity in the face of non-linear encoder readings. A write-up for it is also forthcoming in the not-too-distant-future.
• Transparent no-BRS CAN-FD communication: If your CAN-FD network is only capable of operating at 1Mbps, and you send queries frames with BRS turned off, moteus will now respond in kind. This eliminates most needs to change the CAN bus frequency due to marginal electrical properties.

This is an exciting time for moteus, and the new features will keep coming!