Hi Dh,
I imagine you need to place parts into an ordinated scheme, say n rows by m lines. We usually refer to such a scheme as a “pallet”, and the entire task as “pallettizing” parts.
The problem is usually to maintain the number of position below a reasonable level, because pallettizing parts in a 10 by 10 pattern will require - in principle - 100 positions.
Worse, you’ll probably need at least two “fly-by” positions to reach the placing point ad to get back, so now we have 300 positions.
Let’s start from the 1 position pick-place cycle. You’ll have something like that:
MoveJ pHome, v100, fine, tool1;
WHILE TRUE DO
! Pick
MoveJ offs(pPick, 0,0,100), vmax, z10, tool1Wobj:=woPick;
MoveL pPick, v100, fine, tool1Wobj:=woPick;
Set doGrab;
WaitTime 1;
MoveL offs(pPick, 0,0,100), v100, z10, tool1Wobj:=woPick;
! Place
MoveJ offs(pPlace, 0,0,100), vmax, z10, tool1Wobj:=woPlace;
MoveL pPlace, v100, fine, tool1Wobj:=woPlace;
Reset doGrab;
WaitTime 1;
MoveL offs(pPlace, 0,0,100), v100, z10, tool1Wobj:=woPlace;
ENDWHILE
In this example, I use the offs function to build “fly-by” positions directly in the program. This allows me to:
- save some positions
- fly-by positions follow pPick and pPlace if the user change them.
Now, the easiest way to create a pallettizing pattern, is offseting pPlace with predefined X and Y deltas.
CONST num dx:=50;
CONST num dy:=50;
VAR num i:=0;
VAR num j:=0;
MoveJ pHome, v100, fine, tool1;
WHILE TRUE DO
! Pick
MoveJ offs(pPick, 0,0,100), vmax, z10, tool1Wobj:=woPick;
MoveL pPick, v100, fine, tool1Wobj:=woPick;
Set doGrab;
WaitTime 1;
MoveL offs(pPick, 0,0,100), v100, z10, tool1Wobj:=woPick;
! Place
MoveJ offs(pPlace, idx,jdy,100), vmax, z10, tool1Wobj:=woPlace;
MoveL offs(pPlace, idx,jdy,0), v100, fine, tool1Wobj:=woPlace;
Reset doGrab;
WaitTime 1;
MoveL offs(pPlace, idx,jdy,100), v100, z10, tool1Wobj:=woPlace;
i:=i+1;
IF i>=10 THEN
i:=0;
j:=j+1;
ENDIF
IF j>=10 THEN
! Pallet complete
STOP;
i:=0;
j:=0;
ENDIF
ENDWHILE
First, this program has the drawback that pPlace cannot be easily modified.
Second, if you need to “tune” positions (tipically to keep the pallet tight), you’ll need a lot of extra-code.
The solution is using a persistent matrix of positions, in the form pPlace{i,j}. Usually I put a procedure to calculate all the positions, using offsets in two nested FOR loops. Next, I (or the user) can modify the elements in the matrix even one by one. Fly-by position will automatically follow.
I hope this will help you.
Claudio
. Currently my company Custom Pak (a blow molding plastics company) has been incorporating robotics into some of the tasks that were either very difficult or impossible for people to do, such as cuts on certain plastic parts. How ever we are currently trying to put a robot on one of our blow molding machines, I have the robot reaching into the blow molding machine, grabbing the part, taking off any excess plastic, and then put into a fixture to create holes in the part. I am currently quite confused of how i should pack the parts into a box, I have never used an offset before and no extremely little about them, any help would be greatly appreciated!
.