Back-of-an-envelope analysis:
1. Is this a "do one stack" proof of concept or is it for production?
2. Are the stacks of newspapers in a fixed position such that the robot must move along the stacks or are the papers moved to the robot?
- how will the robot move (guidance, power train)?
- how will the robot be powered?
3. Locate stack of newspapers
- known distance away from the robot?
- known distance from previous stack?
- all papers in stack are oriented the same way?
- all papers are within some tolerance (+/-) of each other?
- - i.e., smooth stack versus random pile
4. Locate edges of newspaper
- IR, sonar, light/dark sensor, microswitch?
- able to determine edge that opens?
- (already known if orientation always the same)
- save locations of sides for later use
5. Measure thickness of paper
- move paper slightly and measure distance from top of upper paper to top of next paper
- divide by two to get midpoint distance
- do this once and save for other papers in this run
- this should be part of the robot's "training" sequence
6. Move robot arm beyond the open edge of the paper
- distance depends on length of the paper lifting/clamping device
(7 assumes a device like tongs with rubber tips)
7. Insert lifting finger (thin metal or plastic) into paper at midpoint
- lift slightly
- insert lower arm of clamp
- close lifting device on upper half of pages
- closing force determined by thickness & weight of paper
- clamp device needs to be thin, strong, and have tips that can grip the paper
8. Lift and move in direction needed to open the paper
- amount of lift probably 4x the thickness of the paper
- amount of movement for opening is a little less than twice the width of the paper
9. Move opened paper to desired position
- (could be part of opening sequence - item 8)
- (need to include in "training" sequence, or have separate "stack finder" arm)
- (save for next paper in this run)
- release clamp
- raise arm
- move back into position to process next paper
- if last paper processed send request for more (or wait for "papers available" signal)
- determined by count if always the same number of papers
- based on thickness of paper and original stack height if count varies
Some of the finding/placing steps can be done once and saved ("training"), assuming the paper size and stacking locations remain constant. Note that the opening device must be able to lift the weight of the paper in order to move it to another location. This will require some serious hardware, as the paper is being moved long distances - the robot arm(s) needed must be able to support and move their own weight plus the weight of the paper.
Depending on the locations of the closed and open stacks, the robot could turn between the stacks (stack locations at 90 degrees) or the opening/moving device could be mounted on a bridge-style framework (stack locations adjacent to each other).
John