Optical Encoders

[Jengles]

Before our team goes to the CORI event on June 23, we are trying to improve our robot. One of our goals is to connect optical encoders to our shooter, and attach a camera to track the hoops. Our shooter uses two Banebot RS-775 motors with P60 16:1 gearboxes. Will the optical encoders given in the KOP work with these, or do we have to buy different encoders?

[Ether]

Originally Posted by Jengles

Before our team goes to the CORI event on June 23, we are trying to improve our robot. One of our goals is to connect optical encoders to our shooter, and attach a camera to track the hoops. Our shooter uses two Banebot RS-775 motors with P60 16:1 gearboxes. Will the optical encoders given in the KOP work with these, or do we have to buy different encoders?

It depends.

How do you intend to mount the encoder, e.g. are using a live or dead axle, what is the axle diameter, direct drive or belt/chain/gear driven etc.

How fast will you be driving the encoder. Do you plan to attach it to FPGA or Jag. Do you plan to use 1x, 2x, or 4x decoding.

How do you intend to use the signal. PID, Take-back-half, Bang-Bang, something else? Some are more immune to noise than others.

[DonRotolo]

The short answer is yes, they can be made to work.

For more details, consider the questions posed by Ether and let us know, so we can offer some suggestions. And, if you don't know what something means, say so, we'll be happy to explain.

[Jengles]

I only know a few of the answers, so I sent an email to two of my programmers/electrical to try and answer the rest. What I know is: the shaft of the gear box is .5in, it is run belt/chain/gear driven etc., and at full speed (but we only go about 35%) it can go up to 3,408 rpm.

[Jengles]

I do not understand the question of dead or live axle. And the other questions I think my programmers should be able to answer.

[Ether]

Originally Posted by Jengles

I do not understand the question of dead or live axle. And the other questions I think my programmers should be able to answer.

Live axle => axle turns with wheel

Dead axle => axle does not turn

[Ether]

Originally Posted by Jengles

I only know a few of the answers, so I sent an email to two of my programmers/electrical to try and answer the rest. What I know is: the shaft of the gear box is .5in, it is run belt/chain/gear driven etc., and at full speed (but we only go about 35%) it can go up to 3,408 rpm.

Here's what I think you said, but I can't tell for sure:

1) Your 775 motor is connected to a gear box.

2) The output shaft of that gearbox is 1/2" diameter

3) There's a sprocket on the output shaft of the gearbox

4) There's a chain on that sprocket

5) That chain goes to a sprocket connected to the wheel

6) The wheel rides on a dead axle.


How and where do you plan to physically mount the encoder?

What is the gear ratio of the gearbox?

What is the tooth count on the two sprockets?

[Jengles]

All of that sounds right, but Im going to post a picture just to make sure.

I do not know how or where we will mount the encoder, what is the best way?

The gear ratio of the gear box is a 16:1. http://banebots.com/pc/P60K-S7/P60K-44-0007

The tooth count I believe a 32 tooth on the big one, and a 10 tooth on the other.

[Ether]

Originally Posted by Jengles

The tooth count I believe a 32 tooth on the big one, and a 10 tooth on the other.

Which one is which.

[Jengles]

Originally Posted by Ether

Which one is which.

Were you able to find it? I also posted the back view of the sprocket.

[Ether]

Originally Posted by Jengles

What I know is: the shaft of the gear box is .5in, it is run belt/chain/gear driven etc., and at full speed (but we only go about 35%) it can go up to 3,408 rpm.

If your gearbox is 16:1 and the output shaft is spinning at 3408 rpm, that means your motor is spinning at 54,528 rpm.

An RS775-12 free speed is 7300 rpm, and an RS775-18 free speed is 13,000 rpm.

You numbers don't add up¹.


¹assuming the pronoun "it" in your post refers to the immediately preceding proper noun, i.e. the gearbox output shaft

[Jengles]

Im having trouble uploading the picture..
If you go to our website www.stcharlesrobotics.com , I just put the picture as the first one.

[Ether]

Originally Posted by Jengles

Im having trouble uploading the picture..

see attachments

[Jengles]

I followed the steps, its not uploading them properly. But the ones one the website work.

[Ether]

Originally Posted by Jengles

I followed the steps, its not uploading them properly. But the ones one the website work.

When you say "it's not uploading them properly", what do you mean by that? Can you describe what is happening?