[NotInControl]

Originally Posted by sparkytwd

I think your best bet is to use encoders on the drive wheels. The optical sensors in mice don't have to have super low error accumulation. 2 years ago, my team had good luck with differential steer drive dead reckoning. I think we worked out that accumulated error over an aggressive 2 minute match would be less than a foot.

It depends on what the original poster is trying to achieve which determines if encoders on the drivetrain will meet their needs or not.

Encoders on the drivetrain will spin if the wheel slips, so the sensor will indicate motion even when the robot base is not moving. I.e when the robot is stalled against the wall or another robot or when slipping during a rotation.

Most of the time if your just focused on auto this usually isn't a concern for many teams in Autonomous, but if the user is after true position of the robot base, encoders on the drivetrain won't work. A global sensor is required.

There are only only a limited number of gobal sensors available to the FRC environment, because were indoors, on carpet, high EMI, etc, and even then each case has their pros and cons. No soluton is an end all be all solution. It just depends on what the OP is trying to achieve.

As a control engineer you want to find the sensor which tells you the information you need, or can deduce rather quickly, and fully understand when the sensor information provided is invalid. Becuase there will be times its invalid

Regards,
Kevin