am-3009 Swerve Encoders

Our new team, 7400, has taken on an off-season project of building a swerve drive robot using 4 am-3009 modules. Everything seems to be working fine. We are using an absolute encoder (am-2899) for steering which works great. We are looking for some guidance on mounting an encoder to the CIM such that we can drive via PID speed control as well as way-point nav during autonomous. Any suggestions ?

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I recommend using these (http://www.andymark.com/encoder-p/am-3314a.htm) because they can easily interface with the CIM motor and don’t require making any extra structure (remember to account for the gear ratio in the program though). Do note that the Andymark swerve plus these encoders on drive and the absolute encoders on rotation is probably not sufficient enough for a competition robot, but the set up you have plus CIMcoders is great for learning in the offseason.

The Cimcoders Tomithy listed will work for you. We have used the swerve and steer modules for the last two years and they do work in competition, but we did do a few things to make them hold up a bit better. We added the Cimcoders and the absolute encoders that you listed. We also drilled and threaded the bottom of the steering gearbox shaft to take a screw and washer which we locktited in. This will capture the steering gear on the shaft which also keeps the key from falling out. This was necessary on the models from the last few years. I am not sure if that has changed this year as the new PG gearboxes are now hex shafts and not round with key ways. We also added a hole to the web of the steering gear to give access to the screws that hold the steering motor in. On our original modules the steering motors would work loose over time.
The weakest point in the module has been the pinion that is clamped directly to the cim motor. When we take the modules apart to add the cimcoders we add in a 2x4 mm key (we shave a 4 mm down to 2 on one side). The clamping collars that hold the pinion on the cim tend to bottom out early and do not provide enough clamping force over long periods of play. We have removed some material from the gap in the collars to allow them to close tighter when necessary.