233 telescoping arms how do they work?

[coalhot]

Originally Posted by bliz213

My team came to Champs this year with the goal to scout robots, sadly not to compete. A small crew of my team members and I went to close to 70 teams and took close up pictures of different their robots.

https://www.dropbox.com/sh/3fxabc28nvvkcr8/A2tQie9tgK

We spent Friday and Saturday running from pit to pit to get all of these pictures. There are close to 1000 pictures neatly organized by team number.

Hope those teams that couldn't make it can enjoy these pictures.

From one of the post photos threads. Look at 254's set, there are a few really good shots of the arm, and the bearing assemblies it rides on.

[smart1]

thanks for the pics

[Mike Marandola]

Originally Posted by coalhot

From one of the post photos threads. Look at 254's set, there are a few really good shots of the arm, and the bearing assemblies it rides on.

This is awesome. I wasn't able to check out some robots up close at worlds so this is great.

[Tom Line]

I understand the structure - the roller bearings and ball bearings etc.

How exactly are the belts driven and cascaded through the system? I'm not seeing how they are connected or function.

[coalhot]

Originally Posted by Tom Line

I understand the structure - the roller bearings and ball bearings etc.

How exactly are the belts driven and cascaded through the system? I'm not seeing how they are connected or function.

I'm not sure. The closest photo I could find is this.

Maybe someone from 254 or 233 could chime in, or you could spend about an hour looking at old 233 posts. I remember coming across a thread where 233 explained how their arm extended and operated (2007 version). Also, 254 talked about how theirs worked in the 7 second climb revel thread.

If I remember correctly (and don't quote me on this), 233 used a spring extend, while 254 didn't.

[ablatner]

I remember it's a single belt going all the way through that's fixed to the stage that extends the most. I could figure out the belt path and pulleys from memory, but I'd have to spend some time drawing it out.

[DampRobot]

Originally Posted by Tom Line

I understand the structure - the roller bearings and ball bearings etc.

How exactly are the belts driven and cascaded through the system? I'm not seeing how they are connected or function.

Imagine a single stage system for simplicity. The belt is pulled by a pulley at the bottom of the "zeroth" stage, and runs over a idler at the top of the zeroth stage. The belt then connects to the bottom of the first moving stage. When the stages are together, the length of the belt is ~2*stage length. When the first stage is extended, the length of the belt is ~1*stage length. Retraction works in the opposite way.

A two stage system works similarly, but with the bottom and top of the first stage being idlers, and the belt being connected to the bottom of the second stage.

I believe there's a pretty good paper on CD-Media which explain all of this in more detail.

[coalhot]

Also, specifics on this thread link

Spending a few minutes searching can get you a long ways along...

[Travis Schuh]

Originally Posted by coalhot

From one of the post photos threads. Look at 254's set, there are a few really good shots of the arm, and the bearing assemblies it rides on.

That exposed bearing assembly pictured in the referenced photos is for the simple level 1 hanger (hook on the end of a piston), which is entirely separate from the 233 climber arms. I am pretty sure that the 233 climber arms use bearings for only the front-back sides and use plastic on the other two sides.

-Travis