The Best Encoders for Drivetrain

[btcshields6]

Hi all!

I'm sure if this is the best place to post this, but as you can, I'd like to try and find the best encoders for drivetrain motors. Please, give me any thoughts and opinions you have on what to use, or tell me what your team does on their drivetrain.

Thanks,

Benjamin

[eddie12390]

We prefer Grayhill 63R over any of the other offerings that we've tried. We've had no issues with them skipping counts or anything like that and they are a lot more rugged than the ones that we've used from US Digital Encoders.

[Gregor]

Second the Greyhill 63R. We use them everywhere.

Worth the price. You can't scratch them and you can use them year after year.

[Lemon]

We've had great success with the analog versions of the US Digital MA3 encoders

[ice.berg]

We are using the Grayhill 63R encoders this year as we are using the vexpro gearboxes as well. So far after a ton of testing and one regional we have had no issues and are very pleased. They are so much easier to use compared the the common US digital E4P. They are available in a few different CPR options as well.

[Munchskull]

My favorite so far have been the AMT103-V Kit encoders. That said they new to us this year. however they are cheaper than most encoders, in addition they fit most shafts and are less temperamental than optical and mechanical encoders.

[z_beeblebrox]

Originally Posted by Munchskull

My favorite so far have been the AMT103-V Kit encoders. That said they new to us this year. however they are cheaper than most encoders, in addition they fit most shafts and are less temperamental than optical and mechanical encoders.

We're also having success with those (and the 102 variant). 6 on our robot.

[Owen Busler]

For those of you using the Grayhill 63R, how do you connect your shafts to the encoder?

Just making sure im looking at the right one

http://www.futureelectronics.com/en/...R256.aspx?IM=0

[Oblarg]

Originally Posted by Owen Busler

For those of you using the Grayhill 63R, how do you connect your shafts to the encoder?

Just making sure im looking at the right one

http://www.futureelectronics.com/en/...R256.aspx?IM=0

Surgical tubing and zipties actually works very well.

[Chris is me]

Originally Posted by Oblarg

Surgical tubing and zipties actually works very well.

Don't even need the zip ties. Get the .25" ID tubing, or even slightly smaller. Muscle it on and you have a rugged, flexible connection that doesn't twist or otherwise muck up your sensor readings.

Alternately, you can press fit the encoder into a .25" hole in a driveshaft, provided you have some LOOSE way to mechanically constrain the encoder from spinning.

If it wasn't clear, I'm also a fan of the Greyhills.

[Dunngeon]

Originally Posted by Chris is me

Don't even need the zip ties. Get the .25" ID tubing, or even slightly smaller. Muscle it on and you have a rugged, flexible connection that doesn't twist or otherwise muck up your sensor readings.

Alternately, you can press fit the encoder into a .25" hole in a driveshaft, provided you have some LOOSE way to mechanically constrain the encoder from spinning.

If it wasn't clear, I'm also a fan of the Greyhills.

We've had great success mounting the 63r directly into the hex shaft.

We drill a .25 hole in our shaft with the lathe, then using a bit of hot glue push the encoder into the hole. Zip tie the wires to something rigid nearby and you're in business. The only thing to be wary of is ensuring that your tail stock and chuck head are aligned correctly, if they aren't the encoder will wobble quite a bit when the shaft is spinning.

[GeeTwo]

For coupling, we've used 1/4" shaft couplers. On our air cannon (in which we made a mini-cim and TB-mini into a servo), we coupled the shaft on the mini to the stub on the back of the gearbox and a potentiometer. This provided plenty of support for the pot - we just had to keep it from rotating. We found that some 10GA steel wire fits those encoder mounting holes nicely. We bent about 8" of this wire into a sufficiently rigid structure to hold the pot in place.

[Munchskull]

Question for the people using grey hill encoders. Why don't you use a more structurely sound mounting method or an encoder that let's a shaft in to it?

[SJaladi]

Originally Posted by Munchskull

Question for the people using grey hill encoders. Why don't you use a more structurely sound mounting method or an encoder that let's a shaft in to it?

In the experience of Team 1923, because we lack the machining resources to mount an encoder perfectly concentric to the shaft that it needs to connect to, we prefer to use a mounting/coupling system that allows for some misalignment. In the past we've used shaft couplers that are flexible and allow for some misalignment, but once we discovered that surgical tubing gives us the same degree of precision that the flexible coupler did, we chose to use surgical tubing as it is much cheaper and easier to service.

As for the structurally sound part of your question, as far as my experience with encoders goes, we've never had an application which required a lot of rigidity. We generally just make a small Lexan tab that we bolt the encoder to and then we mount the tab so that the encoder is as close to concentric with the shaft that we want to couple the encoder to as possible.

Hope that answers your questions!

[ice.berg]

Originally Posted by Munchskull

Question for the people using grey hill encoders. Why don't you use a more structurely sound mounting method or an encoder that let's a shaft in to it?

The encoder is still mounted to our gearboxes soundly, its just the coupling between the gearbox shaft and the encoder shaft that the surgical tubing is used.

A. Cost - for four corners its cents for surgical tubing compared to the 15+ dollars per corner for precision couplers.

B. Vibration - the surgical tubing spins the shaft but at the same time limits a lot of the vibration transfer into the encoder generated by the gears and robot moving around.

C. Misalignment - Goes hand 'n hand with vibration. The surgical tubing allows for slight misalignment of the encoder and the output shaft. Where as a precision coupler is not as forgiving. The grayhill encoders are quite durable compared to others but still we want to limit the extra load caused from misalignment