Palletizing block with different heights

jesusvaricap · January 12, 2017 at 4:30 AM

Hello ,

KRC1 Vkr200/2
kss 4.1.14 pp02

My application its the next :

stack blocks with different heights max tolerance +/-3cm
first stack block on vertical position , next block horizontal position , i repeat this operation for 12 stacks.

i fabricate the gripper , with sensors necessary to do it , and reconfigured 16 I/O digital via DeviceNet

As the blocks has different heights, and need to be released to 5 mm up ( for the characteristics of the block and characteristics for the gripper )

My idea its the next:

-the robot took the first block
-open the gripper and stack on vertical position (the first block was released at floor)
-the robot took the second block
-the robot was moving down, until detect the first stack using a sensor attached to bottom of gripper
-the robot stop when detect the first stack
-the robot move up 5mm
-the robot released the second stack on horizontal
-the robot took the 3rd block
-the robot was moving down, until detect the second stack using a sensor attached to bottom of gripper
-the robot stop when detect the second stack
-the robot move up 5mm
-the robot released the 3rd stack on vertical
.......

all these was repeated to stack 12 blocks

Question 1
how can i transfer to KRL the part :
-the robot was moving down, until detect the X stack using a sensor attached to bottom of gripper
-the robot stop when detect the X stack
?
Question 2
when the sensor was activated how i transfer to KRL
-the robot move up 5mm
?

Maybe i can use something like this:

Code

Home
;first stack
open gripper 
ptp
ptp
lin
close  gripper
lin
ptp 
ptp
lin
open gripper
lin
ptp
;end first stacking


ptp
ptp
lin
close  gripper
lin
ptp 
ptp
lin
open gripper
lin
ptp


detect_stack ()
move_up_5mm ()


Home

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Question 3 :
If its possible , how can i put on a "FOR cicle" to do this 12 times

Thanks a lot BR,

**SkyeFire** · January 13, 2017 at 2:06 PM

Expert Programming Manual: https://www.robot-forum.com/robotforum/man…ss-version-5-2/

Look up: FOR loop, Interrupt, $POS_INT, "Geometric Operator."

**panic mode** · January 13, 2017 at 6:04 PM

i don't quite follow the process but your program seem to be doing a lot of detecting/scanning and - that is very time consuming.
did you consider using laser distance sensor? you can take reading instantly and be on your way to pickup or drop part...

jesusvaricap · January 18, 2017 at 12:08 AM

skyfire, panic mode , thanks a lot for you reply.

i like the idea to use a laser, did you suggest to me a brand, kind , model laser ?

But before to bought a laser i like to start using digital inputs, to detect the stack, and instantly stop the robot, then move up 5mm

As skyfire suggest to me , yes , i know that i need to use the things mentioned before.

i need to stop the robot using an interrupt:

Code

INTERRUPT 1 DECL 1 when $IN[1] do detect_stack ()

yes , work it , the robot stop , but i need to confirms messages , yes i can configure de aut ExT and assig a diital input to config mess, but i need to made the hardware apropiate when the interupt On

so inside a program i put the next code :

Code

...
repeat
lin {z-1} c_dis
until $in[1]==true 
lin {z+5} c_dis
...

the robot moves down with little increments on z negative with low speed , using the parameter $vel.cp=0.010
until the $IN[1] comes high ! the next process its the robot up on z positive 5mm

but doesnt work ! the robot not stop!
i try using flags

Code

...
repeat
lin {z-1} c_dis
until $flag[1]==true 
lin {z+5} c_dis
...

on sps put:

$flag[1]=$out[1]

attached found the programs for more details.

BR

hermann · January 18, 2017 at 10:11 AM

Your code with the repeat .. until should work.
But the problem is that the standard value of $advance is 3.
So Your loop will stop after 3 loops after detecting the signal.
One 'solution' is to set the $advance to 1 or 0. The value 1 means that the loop will stop after one more loop after detecting the signal, the value zero inhibits the advance and the c_dis statement will have no effect, so the robot will stop after every move.

In this cases always use an interrupt.
This is discussed in some other threads.

**panic mode** · January 18, 2017 at 2:34 PM

this is not going to work...

for example you are not setting tool and base, so last used inline form motion will determine tool and base.
this means you are using world coordinate system so your loop will send repeatedly robot to a point that is bellow floor:

LIN {Z -1} ; note, world origin is at Z=0

you may want to consider LIN_REL instead of LIN.

**SkyeFire** · January 18, 2017 at 3:35 PM

The simplistic way:

Code

Shift = $NULLFRAME
Shift.Z = -1.0
REPEAT
  LIN_REL Shift
UNTIL (($POS_ACT.Z < MinimumHeight) OR $IN[1])
WAIT SEC 0
Shift.Z = 5 + $ADVANCE ; compensate for Advance-run lag
LIN_REL Shift

The correct way to handle this is to use interrupts. However, using Interrupts properly requires setting up a chain of subroutines correctly:

Code

DEF Main()
  DECL INTERRUPT 10 WHEN $IN[1] DO PartFound
  PTP SearchStartPosition
  SearchMotion()
  ; RESUME command jumps program pointer here
  LIN {X 0,Y 0,Z 5,A 0,B 0,C 0} : $POS_INT ; move to position 5mm above location where $IN[1] was detected
END


DEF SearchMotion()
  INTERRUPT ON 10
  LIN SearchEndPosition ; set this point slightly below the detection height of the lowest part
END


DEF PartFound()
  BRAKE ; halt motion currently in progress
  INTERRUPT OFF 10 ; prevent double triggers
  RESUME ; jump the program pointer back to Main, one line after StartMotion -- this terminates SearchMotion()
END

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jesusvaricap · January 19, 2017 at 1:56 AM

thanks to all for you reply's Panic mode, hermann , Skyfire

Skyfire , your example work correctly
but with a little changes

as you see i remove with ";" some parts like:

Code

;lin {x 0 , y 0 , z 100 , a 0 , b 0 , c 0} : $pos_int
;shift.z=100 + $advance
;lin_rel shift

and put it :
shift.z=100 + $advance
lin_rel shift[/code]
on the section: "searchmotion ()"
an add:

Code

$VEL.ORI1=100
$VEL.ORI2=100

what happend wih the sections
lin {x 0 , y 0 , z 100 , a 0 , b 0 , c 0} : $pos_int
shift.z=100 + $advance
lin_rel shift

why doesnt work ? why the problem "read protection" ? (picture attached)
ive not reconfigured tool and base yet , im doing tets on the "air" to avoid crashes

here the code that work correctly :

Code

DEF main( )
PTP HOME
INTERRUPT decl 10 when $in[1] do part_found ()
LIN P2 ;SearchStartPosition
searchmotion ()
;position[i]=$pos_int
;lin {x 0 , y 0 , z 100 , a 0 , b 0 , c 0} : $pos_int
WAIT SEC 1
shift.z=5 + $advance
lin_rel shift
END
DEF searchmotion ()
interrupt on 10
$VEL.ORI1=100
$VEL.ORI2=100
LIN P1 ; set this point slightly below the detection height of the lowest part
search ()
END
DEF search ()
shift=$nullframe
shift.z=-1.0
repeat
lin_rel shift
;until (($pos_act.z < 500) or $in[1])
until $in[1]==true
;shift.z=100 + $advance
;lin_rel shift
end
DEF part_found () 
BRAKE
INTERRUPT OFF 10
RESUME

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attahed 2 programs: "main" work correctly and main "main2" appears error read protection

so , i just need "polish"the program to palletizing 12 stacks wih a for ,op/cl gripper etc

**panic mode** · January 19, 2017 at 4:18 AM

no offense but this has no hope of working in this form, some major reconstruction is needed

in order to write working programs, one must read manuals and understand what each instruction does...

some of the notable issues include:

adding $advance to position variable makes no sense,
$POS_INT is only usable inside interrupt subroutine (this is why you get the message)
there is nothing to turn off interrupt after search (if interrupt was not triggered during search - it remains active... this is how you crash robot! worse - this can happen weeks after programming was "complete").
there is no need to do loop etc inside search motion - single long motion instruction is all you need, no point in "inching" (moving mm by mm).
there is no need to check for $in[1] inside search routine
there is nothing to keep advance run pointer inside search routine during search,

**SkyeFire** · January 19, 2017 at 6:37 PM

To be fair, most of those mistakes are mine -- I was just dashing off some concept-example code that was never intended to be fully bulletproof.

Forgot about that $POS_INT quirk. Need to record it to another variable inside the interrupt routine. And add a WAIT SEC 0 or something to the Search routine.

And yes, I neglected turning off the Interrupt in the event of a failed search.

Adding $ADVANCE to the position variable was to compensate for the "overshoot" effects of the Advance pointer when using a simple 1mms/step search routine (which I forgot to put C_DIS on, )

jesusvaricap · January 20, 2017 at 11:06 PM

panic mode, thanks for your advices!

of course , i need to reconstrcut it
about:
there is nothing to turn off interrupt after search (if interrupt was not triggered during search - it remains active... this is how you crash robot! worse - this can happen weeks after programming was "complete").
yes i need to create something to prevent it
there is no need to do loop etc inside search motion - single long motion instruction is all you need, no point in "inching" (moving mm by mm).
yes, maybe i just need to move the robot on "-z" , and ON an interrupt , the interrupt was triggered when $in[1]
there is no need to check for $in[1] inside search routine
did you reefer to use an iterupt?
there is nothing to keep advance run pointer inside search routine during search
the stack need to delivery up 5mm (the tongs of the gripper interfere with the stack from the down ), als as skyfire say to compensate for the "overshoot" effects

thanks.

**panic mode** · January 20, 2017 at 11:30 PM

Quote

there is no need to check for $in[1] inside search routine
did you reefer to use an interrupt?

no, I mentioned loop that is inside SEARCH()

Code

repeat
lin_rel shift
;until (($pos_act.z < 500) or $in[1])
until $in[1]==true

when $IN[1] turns true, ISR is called, RESUME command kills everything bellow level where interrupt is declared and program returns to MAIN(), just after SEARCHMOTION()

so inside SEARCH() code after loop never happens either

Code

shift.z=100 + $advance
lin_rel shift

**SkyeFire** · January 23, 2017 at 4:37 PM

Okay, those were two different examples of how to go about this.

The loop-search was the primitive but easy method. The Interrupt-based search is better, but more complicated. These two programs do not mix. SearchMotion() and PartFound() are part of the interrupt-driven method. Search() is the loop-based method. You cannot use both.

**panic mode** · January 25, 2017 at 8:24 PM

that may be intention but it is not how they work.
in both cases SEARCHMOTION() calls SEARCH(), both use interrupt with $IN[1] and in both examples there is a loop evaluating same input as used as interrupt condition.

Palletizing block with different heights

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