String to number conversion and checking the reachability in RAPID

pion3k

Hello,

I need some help with the following problems:

1) Is it possible to somehow convert a string (in my case received through a socket) to the equivalent data but in a number type in RAPID? I have tried with StrToByte but the problem is that I'm significantly limited by the range of the byte type (0 - 255 without negative values). What I need is to  by the socket the position of the robotic arm and, as you know, the position of the effector can quite a bit exceed the limit (255). I thought about multiplying the values but in this case I would lose a possibility of reaching intermediate points. And still, what about negative values?

2) How can I check a reachability of a specified point by a RAPID code? Generally, my program crashes now when the coordinates of the demanded point are exceeding the robot's workspace limit.

soup

1. StrToVal allows you to convert a string to positive or negative number.

2. Find out your max x, y, and z you can reach and use an IF statement to check that your positions are valid before sending the robot too far/crashing the program.

msalminen

I use following function to check the reachability.

  FUNC bool IsReachable(robtarget pReach, PERS tooldata ToolReach, PERS wobjdata WobjReach)

  ! Check if specified robtarget can be reach with given tool and wobj.
  !
  ! Output:
  !  Return TRUE if given robtarget is reachable with given tool and wobj
  !  otherwise return FALSE
  !
  ! Parameters:
  !  pReach     - robtarget to be checked, if robot can reach this robtarget
  !  ToolReach  - tooldata to be used for possible movement
  !  WobjReach  - wobjdata to be used for possible movement

  VAR bool bReachable;
  VAR jointtarget jntReach;
  
  bReachable := TRUE;
  
  jntReach := CalcJointT(pReach, ToolReach\Wobj:=WobjReach);
  
  RETURN bReachable;
  
  ERROR
   IF ERRNO = ERR_ROBLIMIT THEN
    bReachable := FALSE;
    TRYNEXT;
   ENDIF
  ENDFUNC

samatsimt

Thank you msalminen. I think the ERR_ROBLIMIT parameter could be very useful. I have a modified version but cant get it working. Will you have a look please? It is the first time I'm doing error handling so Im not sure if im clear of the functions like "ERROR" and "TRYNEXT" . I think the use of CalcJointT is essentially just to exploit its ability to generate an error code, which we try to make use of?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                MODULE MODNAME PERS num bReachable:=0; PROC mMain CheckReachable TheTarget,ActiveTool; !Only try to move if it is reachable. IF bReachable=1 THEN movej TheTarget,TheSpeed,TheZone,ActiveToolj; ENDIF ENDPROC PROC CheckReachable(robtarget pReach,pers tooldata ToolReach,\pers wobjdata WobjReach) VAR jointtarget jntReach; bReachable:=0; IF present(WobjReach) then jntReach:=CalcJointT(pReach,ToolReach\Wobj:=WobjReach); else jntReach:=CalcJointT(pReach,ToolReach); endif ERROR IF ERRNO=ERR_ROBLIMIT THEN bReachable:=2; TPWrite "NOGO"\Pos:=pReach.trans; TRYNEXT; else bReachable:=1; TPWrite "GO"\Pos:=pReach.trans; TRYNEXT; ENDIF ENDPROC ENDMODULE

samatsimt

Wait, where do I find the text/code formatting tools?

samatsimt

i hope this works..

msalminen

Hi samatsimt, You routine seems to set bReachable to 0, if the robtarget is reachable. You check in main if it's 1. So change the line bRechable:=0; to bRechable:=1; The error handler never fires if CalcJointT can calculate the position, so your If/else in error handler don't work. Regards, Mika

msalminen

text formatting here seems not to work... Mika

samatsimt

Hi msalminen, thank you. I have made the changes according to your suggestions but the flow controls seems to be acting weird. The designed list of robtargets goes from easy to reach to unreachable incrementally, so I sort of know when the error will occur.                                                                                                                                                                                                                                                                                                                                                                                                            But the weird behavior is that the program goes into the ERROR section and prints the "NOGO" lines even when the robot is moving well in the simulation. When it finally goes to the robtargets which is in fact impossible, then only it will stop execution and gives error messages in the output/debug tab.                                                                                                                                                                                                                                                                                      The motivation behind my question is in https://forums.robotstudio.com/discussion/9306/quick-way-to-eliminate-non-reachable-robtargets-from-list-of-many-robtargets#latest                                                                                                                                                                                                                                                                                                                               How did you get the code formatting to work in your first post in this thread?

msalminen

Hi, Add RETURN; before the ERROR line. This is old thread and old post was done with previous site/format where it woked just fine. This new look/site/format not working well at least for me with windows 7 PC. Mika

SteveMob

Hello,

I am using Samatsimt's modified code. I am trying test if a given robtarget is within reach or not. If it is, it moves to the target. If the target is not in reach, then the robot is supposed to go "Home". For some reason I cannot get bReachable to equal 2 if the robtarget is not in reach. Attached is some snippets of my code, can anyone help me and tell me where my mistake is? If I declare bReachable:=0, then the program never moves the robot, and bReachable will stay at 0 unless I send a target that is out of reach, then it only changes to 1 (which it should change to 2). If I declare it to equal 1 in the beginning, all it does is keep bReachable at 1, no matter if the target is within reach or not.. So essentially the error handler isn't working correctly I think. Any ideas?
My Code:

Module Module1

PERS num bReachable:=0;
Proc Main()

                        CheckReachable myRobtarget,tool0;
                        IF bReachable=2 THEN
                            MoveJ Home,v100,fine,tool0,\WObj:=wobj0;
                        ELSEIF bReachable=1 THEN
                            MoveJ myRobtarget,v100,tool0,\WObj:=wobj0;
                        ENDIF
ENDPROC

PROC CheckReachable(robtarget myRobtarget,PERS tooldata ToolReach1,\PERS wobjdata WobjReach1)
        VAR jointtarget jntReach1;
        IF Present(WobjReach1) THEN
            jntReach1:=CalcJointT(pReach1,ToolReach1\WObj:=WobjReach1);
        ELSE
            jntReach1:=CalcJointT(pReach1,ToolReach1);
        ENDIF
        RETURN;
    ERROR
        IF ERRNO=ERR_ROBLIMIT THEN
            bReachable:=2;
            TRYNEXT;
        ELSE
            bReachable:=1;
            TRYNEXT;
        ENDIF
ENDPROC
ENDMODULE

If anyone can help me, I would greatly appreciate it!!
Thanks,
SM

graemepaulin

The manual states the ERR_ROBLIMIT is when the target is reachable but at least one axis is outside the joint limits...

So you should add (or change) the ERRNO to ERR_OUTSIDE_REACH which is where the target is outside the reach of the robot.

Also the code will not enter the error handler if the target is reachable which is why it is not changing the variable value if you set it to 1 in the declaration (it is executing the ELSE part of the error handler), and also means the variable will not be set to 1 when reachable (if set to 0 in the declaration).

Try this modified code.

Module Module1

PERS num bReachable:=0;

  Proc Main1()

      CheckReachable myRobtarget,tool0;

           IF bReachable=2 THEN

                    MoveJ Home,v100,fine,tool0,\WObj:=wobj0;

           ELSEIF bReachable=1 THEN

                  MoveJ myRobtarget,v100,tool0,\WObj:=wobj0;

          ENDIF

    ENDPROC

  PROC CheckReachable(robtarget myRobtarget,PERS tooldata ToolReach1,\PERS wobjdata WobjReach1)

      VAR jointtarget jntReach1;

      bReachable:=1;

      IF Present(WobjReach1) THEN

              jntReach1:=CalcJointT(pReach1,ToolReach1\WObj:=WobjReach1);

      ELSE

             jntReach1:=CalcJointT(pReach1,ToolReach1);

      ENDIF

      RETURN ;

      ERROR

         IF ERRNO=ERR_ROBLIMIT or ERR_OUTSIDE_REACH THEN

                bReachable:=2;

               TRYNEXT;

        ENDIF

  ENDPROC

ENDMODULE