Dual Scorbot Arm Concept
- Design News just covered an interesting idea...
... a tandem robot arm system by ST Robotics, that simply
combines a pair of arms on a turntable: (Very cool...)
Video: ST Robotics' 11-Axis Tandem Robot System
Direct link to the embedded YouTube video:
I am wondering if anyone here has ever tried such a
configuration, with Scorbots? Given two Scorbot arms
and the 4 foot (1200mm) linear axis, you could even add
a turntable axis between the linear axis and a pair of Scorbot
arms on a cross plate, to give you massive reach AND run length...
To upgrade the linear axis:
You start with a large plate, and a couple of castors as
"outriggers", and fix it to the linear slide top plate.
This gives the final assembly lateral stability, yet allow
it to slide along the linear axis.
Now add a lazy susan bearing and the cross bar plate,
to hold the two Scorbot arms.
Drive the center of the cross plate's new "rotary axis" with a
geared down axis motor from above the center pivot point
(there is room there, and it doesn't require modifying the
linear axis slide plate).
Add an encoder for feedback, and a pair of limit switches,
so you don't tangle up the wiring to the two arms by
over-rotation of the new table axis.
Run the arm wiring cables through a U-loop cable guide
normally, to allow the linear axis to move, and make a
short loop under the plate to allow for 180-360 deg rotation
of the top plate.
Heck... 360-380 degrees may be overkill. 180-270 deg rotation
is probably more than sufficient for most uses (the perpendicular
to the linear axis each way is IMO the min twist).
You can always drop a part and pick it up with the other arm
if you need to get an angle that one of the arms can't reach.
For control, you cross connect I/O switches on the two
arm's controllers, to sync their programs up. One does
a move, then triggers the other one via the I/O bits.
IOW, they alternate moves, with the standard controllers.
It'll be up to you to watch for collisions in your programming,
but this does make it workable without requiring you
to make a custom dual-controller.
Taa Daa.. a similar robot, with MASSIVE reach!
I have a pair of Scorbot-IIIs and a linear axis.
I'm seriously considering playing with this configuration.
Heck, even without the linear axis, a simple lazy susan
axis immediately gives you some benefits, like "fast
swapping" capacity for a serviced machine.
One arm grabs a part or a tool out of the machine or
a position, and the other one sticks the new part or
tool into it via a simple 180 degree lazy susan move.
IOW you now have "swapping arms", instead of having to
fab a "swapping gripper". This may allow you to use
totally unmodified Scorbots, or ones with simpler to
fab finger sets, for the job!
What else would YOU do, given a 2-arm and lazy susan configuration?
- Keith Mc.
- Keith Mc <acti@...> wrote:
> You can always drop a part and pick it up with the other armA new thought... Directly over the turntable's motor pivot point,
> if you need to get an angle that one of the arms can't reach.
you can place a simple "table", tool holder socket, or cup.
It is a handy, fixed, known place in space for the robot arms
to drop items for exchange between them, AND it always
travels along with the arm pair should you mount the entire
turntable assembly onto a linear axis.
This may reduce the need for a large rotation angle on the turntable.
- Keith Mc.