Motors: Past and Future

[AdamHeard]

Originally Posted by asid61

ESCs (electronic speed controllers) for brushless motors do run on 12v actually, but it actually has to be 12v. Anything more than 12.6v and a little overhead should be avoided. This is because they are designed to be run on lipo battery packs. A 3-cell lipo has a normal voltage of 11.1v, but it's really 12.6v when charged. A lead acid battery like in FRC robots are 13.6v fully charged IIRC, which is a tad too high for a 3-cell ESC. It still might work, but you would have to check.
The voltage drop on the lead-acid battery over time might also be too much for ESCs.
ESCs are actually pretty cheap. Because they are often just SMD parts, I've noticed even cheap ones from places such as ebay work just fine due to the lack of manual work. If you wanted US-made ones though it could cost a bit more. They are usually cheaper than the controllers we use though.

There are plenty of hobby grade ESC's for brushless motors that would work at 13+ V that FRC sees. I have way too many brushless RC cars, and I design brushless motors at a my day job (at a company that also makes the drives for them).

They really wouldn't be much better than brushed motors, just more efficient. Since most of those drives are sensorless in the affordable price points, teams would see issues with cogging as most wouldn't know how to properly size them.

Most of the lower cost controllers handle direction change awful as well, and would only be suitable for flywheels, etc...

The true benefit of brushless motors for FRC would be when we get current control, which is a higher price point controller. We could do some REALLY cool control stuff at that point though, very smooth motion.

If hobby grade brushless motors became available for FRC, it's unlikely we would use them (reliability, the potential cogging issue). I reserve the right to change my mind after testing though. If anything we'd reserve them for applications that never see high stall loads and we can take advantage of their high power and efficiency in the faster range.