RoboStars 'Mini-Arm' Control Device

[archiver]

Posted by Steve Kalemkiewicz.

Student on team #217, Team Macomb, from Cousino High School / CPC and Ford Motor Company.

Posted on 3/20/2000 6:03 PM MST



I was wondering if anyone had a picture of RoboStars' (#308) 'Mini-Arm' Control Device. I'm curious how the mini-arm stays in position after the controler lets go of it. Any other info that could be provided would be helpful.

Thanks

-S Kalemkiewicz

[archiver]

Posted by Michael Martus.   [PICTURE: SAME | NEW | HELP]


Coach on team #47, Chief Delphi, from Pontiac Central H.S. and Delphi Automotives Systems.

Posted on 3/20/2000 9:03 PM MST


In Reply to: RoboStars 'Mini-Arm' Control Device posted by Steve Kalemkiewicz on 3/20/2000 6:03 PM MST:



I have only one word about that arm. WOW!

It goes on forever, and ever.

[archiver]

Posted by Dave.   [PICTURE: SAME | NEW | HELP]


Student on team #308, Robo Stars, from Walled Lake Schools and TRW.

Posted on 3/21/2000 5:51 AM MST


In Reply to: RoboStars 'Mini-Arm' Control Device posted by Steve Kalemkiewicz on 3/20/2000 6:03 PM MST:



Hey,

Being the driver for team 308, not the arm operator, I still know sorta how it works :-) 'Mini-me', as we call it, stays where ever we put it. The friction between the two arm joints on it keeps it there. As pictures, I don't have any, but if you live in Detroit and get the Free Press, on Monday, the 13th, you can see a picture of it. Feel free to ask any other questions!

Dave Hurt


: I was wondering if anyone had a picture of RoboStars' (#308) 'Mini-Arm' Control Device. I'm curious how the mini-arm stays in position after the controler lets go of it. Any other info that could be provided would be helpful.

: Thanks

: -S Kalemkiewicz

[archiver]

Posted by Dave.   [PICTURE: SAME | NEW | HELP]


Student on team #308, Robo Stars, from Walled Lake Schools and TRW.

Posted on 3/21/2000 6:43 AM MST


In Reply to: Re: RoboStars 'Mini-Arm' Control Device posted by Dave on 3/21/2000 5:51 AM MST:



: Hey,

: Being the driver for team 308, not the arm operator, I still know sorta how it works :-) 'Mini-me', as we call it, stays where ever we put it. The friction between the two arm joints on it keeps it there. As pictures, I don't have any, but if you live in Detroit and get the Free Press, on Monday, the 13th, you can see a picture of it. Feel free to ask any other questions!

: Dave Hurt

:
: : I was wondering if anyone had a picture of RoboStars' (#308) 'Mini-Arm' Control Device. I'm curious how the mini-arm stays in position after the controler lets go of it. Any other info that could be provided would be helpful.

: : Thanks

: : -S Kalemkiewicz

[archiver]

Posted by Chris.   [PICTURE: SAME | NEW | HELP]


Coach on team #308, Walled Lake Monster, from Walled Lake Schools and TRW Automotive Electronics.

Posted on 3/21/2000 7:19 AM MST


In Reply to: picture of 'mini-me' eom posted by Dave on 3/21/2000 6:43 AM MST:



Dave, you beat me to it.

The picture is hard to see since the 'mini-me' is made from plexiglass (or whatever we were allowed to use from the additional H/W list). Once again, if you would like to see it in detail, come see us at our pit in Chicago or Disney.

Chris

: : Hey,

: : Being the driver for team 308, not the arm operator, I still know sorta how it works :-) 'Mini-me', as we call it, stays where ever we put it. The friction between the two arm joints on it keeps it there. As pictures, I don't have any, but if you live in Detroit and get the Free Press, on Monday, the 13th, you can see a picture of it. Feel free to ask any other questions!

: : Dave Hurt

: :
: : : I was wondering if anyone had a picture of RoboStars' (#308) 'Mini-Arm' Control Device. I'm curious how the mini-arm stays in position after the controler lets go of it. Any other info that could be provided would be helpful.

: : : Thanks

: : : -S Kalemkiewicz

[archiver]

Posted by Chris.   [PICTURE: SAME | NEW | HELP]


Coach on team #308, Walled Lake Monster, from Walled Lake Schools and TRW Automotive Electronics.

Posted on 3/21/2000 6:02 AM MST


In Reply to: RoboStars 'Mini-Arm' Control Device posted by Steve Kalemkiewicz on 3/20/2000 6:03 PM MST:



: I was wondering if anyone had a picture of RoboStars' (#308) 'Mini-Arm' Control Device. I'm curious how the mini-arm stays in position after the controler lets go of it. Any other info that could be provided would be helpful.

: Thanks

: -S Kalemkiewicz

I don't have any pictures yet. There was a picture of us in the Detroit Free Press on Monday, March 13 and you can see the 'Mini-Arm' controller. I'll try to scan the picture and post it.

It stays in position by building some static friction into the system. We used some rubberized nuts so we could tighten the joints just enough so that the mini-arm would stay in place if you let go of it, but it is still easy to move.

The controller works using a simple proportional feeback control loop. We have potentiometers on the robot arm and on the mini-arm. When there is a difference between the potentiometers of the two arms, the controller multiplies this difference by a gain and this value is sent to the speed controllers on the arm motors. (Almost any engineer on your team could explain this in more detail if you asked.)

We used this type of control since we are using a double jointed arm. If we used joysticks it would be next to impossible to control (if we could control it, it would be sloppy at best). The mini-arm allows for extremely easy and accurate control. In fact, we rely on fast and accurate control since we only hold one ball. Our philosophy is that if we could do it fast enough, we don't need to hold multiple balls (we've done a good job so far - we scored 21 pts. one match by ourselves (and won) when our partner couldn't move their robot). Shown below is a picture of the robot. I will post the free press picture shortly.

If you're going to Chicago, feel free to stop by our pit and have a close look.

- Chris