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Home > Programming > How to know if object is detected or not by wrist camera?
Nerials

The task I want to do: 

If object detected proceed further with program
If object is not detected do something else

How to write program like that? 
Etienne_Samson

@Nerials the Robotiq Wrist Camera use a single command line, Camera Locate.

Camera Locate node act like an "if" statement, so if you detect an object (Camera Locate is "true) everything under the camera locate node is executed.

For example this is a pick and place with camera and counting the number of parts:

MoveJ
   Snapshot_position
Camera Locate
   part_counter = part_counter+1
   MoveL
      Approach_pick
      Pick
      Gripper Close
   MoveJ
      Approach_place
      Gripper Open
In that example, if you don't have any parts, the part counting, the pick and the place are skipped (they are under the camera locate).

You could also do a program with an if and else to count if you are having parts or not:
MoveJ
   Snapshot_position
If Camera Locate
   part_counter = part_counter+1
   MoveL
      Approach_pick
      Pick
      Gripper Close
   MoveJ
      Approach_place
      Gripper Open
Else
   no_parts = no_parts+1
Nerials

Maybe I formulated my question in in wrong manner. I understand the idea that camera locate works like IF statement and when it detects a part it does what is inside the camera locate node if not it proceeds further. But what I want to do is to execute some other code or comand when the part is NOT detected and to stop a normal process. Maybe it will be more clear if I describe my task. 

So I have 3 parts assembly. They need to be assembled in sequence  1, 2 and 3. All these 3 parts are located separetly in different fields of view. 

So for example robot detects part 1 and puts it in assembly station. Then it goes for part 2 if it detects then it goes to put it into assembly and then go for part 3. 
BUT if part 2 was NOT detected I do not want to proceed to PART 3 I want robot to stop and give an error message or try to find PART 2 one more time.
So if everything is detected I want to go with normal flow. But if part is NOT detected I want to execute this "extraordinary" code that would not normally run if parts are detected and everyting is in nice flow. How do I initiate this "extraodinary" code that would stop robot and give an error message ONLY when part 2 is not detected and when it IS detected code would go further with normal comands? 
David_Gariepy

Hi @Nerials

To do this kind of logic, you could simply use a variable for each part and update it in the camera locate node.
In the first example here, the robot will continue searching until it finds the needed part. 

 Program
   BeforeStart
     'initialize variable'
     part_1_detected≔ False 
     part_2_detected≔ False 
     part_3_detected≔ False 
   Robot Program
     MoveJ
       Home
     If part_1_detected≟ False 
       MoveJ
         snapshot1
         Camera Locate
           part_1_detected≔ True 
           'put in assembly station'
     If (part_1_detected≟ True ) and part_2_detected≟ False 
       MoveJ
         snapshot2
       Camera Locate
         part_2_detected≔ True 
         'put in assembly station'
     If (part_1_detected≟ True ) and (part_2_detected≟ True ) and (part_3_detected≟ False )
       MoveJ
         snapshot3
       Camera Locate
         part_3_detected≔ True 
         'put in assembly station'
     If (part_1_detected≟ True ) and (part_2_detected≟ True ) and (part_3_detected≟ True )
       'Do something when assembly is done then reset variable'
       part_1_detected≔ False 
       part_2_detected≔ False 
       part_3_detected≔ False


In the second example here, the robot could execute your extraordinary code if a part isn't found. 

Program
   BeforeStart
     'initialize variable'
     part_1_detected≔ False 
     part_2_detected≔ False 
     part_3_detected≔ False 
   Robot Program
     MoveJ
       Home
     If part_1_detected≟ False 
       MoveJ
         snapshot1
         Camera Locate
           part_1_detected≔ True 
           'put in assembly station'
     If part_1_detected≟ False 
       'part 1 was not detected. execute your extraordinary code here'
     If (part_1_detected≟ True ) and part_2_detected≟ False 
       MoveJ
         snapshot2
       Camera Locate
         part_2_detected≔ True 
         'put in assembly station'
     If (part_1_detected ≟ True ) and (part_2_detected≟ False )
       'part 2 was not detected. execute your extraordinary code here'
     If (part_1_detected≟ True ) and (part_2_detected≟ True ) and (part_3_detected≟ False )
       MoveJ
         snapshot3
       Camera Locate
         part_3_detected≔ True 
         'put in assembly station'
     If (part_1_detected ≟ True ) and (part_2_detected≟ True ) and (part_3_detected≟ False )
       'part 3 was not detected. execute your extraordinary code here'
     If (part_1_detected≟ True ) and (part_2_detected≟ True ) and (part_3_detected≟ True )
       'Do something when assembly is done then reset variable'
       part_1_detected≔ False 
       part_2_detected≔ False 
       part_3_detected≔ False



You'll find the 2 programs example attached if needed.
Regards
Nerials

 Hi @David_Gariepy

Thank you for you input with the code example it was really helpfull ! :)

But now I bumped into some other issue: I used example No. 1 of your template for my script and when I wrote all comands it worked smoothly. But when I SAVED it, it got all messed up. (P.S. Actually I have 4 parts in assembly and two of them are the same Part2 and Part3) . So when I saved my script and run it again the reference frame for Camera Locate node became something totaly different... So when camera detects an object robot dosn't go to pick it up as taught but goes into weird directions nothing like I tought him. 
Somehow  I managed to get back to initial reference frames (in camera locate node) for Part1 detection and Part2 dectetion by changing Features for Move to some other and then back to what is should be. Never the less it did not helped me to do the same for Part3 even thou it is totaly same part in a same location as Part2 and I even copied Move node with waypoints from Part2 to Part3. So now all the waypoints, features, TCP and settings are identical in Part2 and Part3 but when the time comes to pick up Part3 camera detects part and then robot goes nuts direction...
Any tips how to solve this? 

David_Gariepy

Hi @Nerials

  • For the move in the camera locate, did you use movel and set the snapshot use as the feature?
  • Do you use the same snapshot position for all part?  if you use different snapshot position you need to set the feature accordingly in the movel feature. 
  • You might also have to reteach all position, even if when you "move robot here" it move at the correct position. If the move been recorded under another feature, it won't go at the correct position when the program run. 

So just be sure the feature in movel is the one used in the camera locate node, and reteach your waypoint then you should be fine.