bottle opening robot arm

[msk]

I want to make a robot arm that can locate a small bottle on a table, unscrew the cap of the bottle, locate all glasses on the table, then distribute the content of the bottle into all glasses on the table and finally recap the bottle.

I have no experience with mechanical engineering, but I have a friend who works at the mechanical engineering institute at my university who says he can help me out with making parts as long as I design them myself. Because of this I was thinking of perhaps buying a lynxmotion robot arm to use as a base. What my robot arm will be lifting will weight around 75-150 g, so it looks like the SES Arm might be strong enough, but not the Lynx 5 and Lynx 6 arm.

I'm a bit unsure yet of how to make something that can unscrew a bottle cap, but I'm thinking that I should mount an additional rotating gripper perpendicular to the main gripper, that can move up and down to align the extra gripper with the bottle cap and rotate to unscrew or rescrew. I'm not sure how much such a gripper would weigh, and I think it might perhaps weight too much for the SES Arm, so I might have to do something else.

To locate the bottle and the glasses I want to use computer vision, either mounting something like the Backfin SRV-1 on the arm, or hanging a webcam above the table. If I hang a webcam above the table, then locating the center of the bottle and the glasses shouldn't be too hard as they will be circles, and the color can also be used to distinguish them as the bottle will have a colored cap. Then I would just store the height of the glasses and the bottle in the software and it should then be able to calculate the positions it has to move the arm to do everything.

I would appreciate if anyone has any other suggestions for how to do this.

[Xone G0D]

  No offence mate, but with your limited experiance, ~knowledge and giving the complexity of your project, "The turk" might be in order.    
 
http://en.wikipedia.org/wiki/The_Turk

  I dont think you have seen the beer pouring robot(Google it), its pretty close to what you want to do... but instead of an ARM it uses a whole UNITASTIC device. 
 

..X..

[msk]

I have seen the beer opening robot, but it opens cans and not bottles. Chives the butler robot, for which there is a tutorial on this website, is more like what I want, but it uses a wheel to unscrew the bottle cap so the cap flies away and for me it's important that it doesn't.

My limited experience with mechanical stuff is why I wanted to get a robot arm kit to begin with so that I can work on things I have experience with first, i.e. making the software, and then replace and extend parts of the arm as I need.

[msk]

Does this sound like a good way to go about this project?

I'm relatively good at programming and have written some simple computer vision software before, so I have a pretty good idea on how to do the software side.

The main thing I'm unsure about is how to make a gripper that can hold a bottle and at the same time unscrew the bottle cap and finally put it back on, and how to make this in a way so that the arm can lift it. Maybe if it gets heavy I could upgrade the servos, or gearing? Not sure how well fit the lynxmotion arms are for upgrading, anyone know?

[airman00]

Hi
I'm the one who made Chives the butler robot .

You could open up a bottle pretty easily if you are willing to spend a lot of cash on motors and servos.
Just one gripper connected to a servo and another servo on bottom. A bottle only has to turn 360 degrees to be opened. So the servo on bottom turns the bottle 180 to the right, and the gripper part turns the bottle to the left - so it totals 360 degrees.

[msk]

Actually the cap on the bottle I want to open has to turn 720 degrees. I was thinking that I might use one servo for opening/closing the extra gripper to tighten it around the bottle cap, a linear actuator to be able to move it up and down to position the gripper and lift the bottle cap off the bottle, and a DC motor for turning the extra gripper around until it is open. So that from when the main gripper holds the bottle in place, it would look something like this from the front:

    |<----- linear actuator 
    T<----- DC motor     
 __|__
/   U  \ <----- extra gripper for opening the bottle cap
    ||
    ||<---bottle

[airman00]

or gear up each servo so that it can turn to 360 degrees

[msk]

The reason why I want to do it as I described is that part of why I want to build this robot is to get experience and to test things for what I'm planning for my next project, sometime in the far future . That project will require a rotating gripper like, something like what I tried to describe, that has no limit on the number of degrees it can rotate.

[airman00]

then use one of those slip rings things
http://en.wikipedia.org/wiki/Slip_ring

[msk]

So I'd use a slip ring motor to rotate the extra gripper then, right? I'll have to look into these slip ring motors some more.

[airman00]

A slip ring (in electrical engineering terms) is a method of making an electrical connection through a rotating assembly.

You have a motor rotate the slip ring and connect a gripper to the other end of the slip ring. Slip ring connected to wires of the gripper and then the other wires on the other side are connected to your microcontroller.

Some more info:
http://www.societyofrobots.com/robotforum/index.php?topic=4008.0

[Soeren]

http://www.societyofrobots.com/robotforum/index.php?topic=6064.0