Catching Kinematic Error

mkatliar

Dear colleagues,
I am quite new to RAPID programming, so I apologize if my question is too trivial.

I need a mechanism to catch kinematic errors if they happen and continue execution of the program. Example:
MODULE MyModule
    VAR bool error_flag := FALSE;

    PROC MyProc()
        ! The following line generates error 50065 "Kinematic error"
        MoveAbsJ somewhere_out_of_reach, speed, zone, tool;

        ! I want the execution to continue here after the error
        TPWrite "The show must go on!", \Bool=error_flag;

        ERROR
            TPWrite "Hello from error handler!";
            error_flag := TRUE;
            TRYNEXT;        
    ENDPROC
ENDMODULE

However, the ERROR handler is never executed -- the program simply stops and an error message is logged.

What am I missing?

VictorAx

I've done something similar;

MODULE MyModule
    VAR bool error_flag := FALSE;

    PROC MyProc()

        ! Create a temp jointtarget

        VAR jointtarget jntReach;

        ! The jointtarget is crated from the position, somewhere_out_of_reached should be a robtarget

        jntReach := CalcJointT(somewhere_out_of_reach, tool\wobj);

        ! If this point isn't reachable, error ERR_OUTSIDE_REACH or ERR_ROBLIMIT is raised

        MoveAbsJ somewhere_out_of_reach, speed, zone, tool;

        ! I want the execution to continue here after the error
        TPWrite "The show must go on!", \Bool=error_flag;

        ERROR

            SkipWarn; !Don't raise an error

            TPWrite "Hello from error handler!";
            error_flag := TRUE;
            TRYNEXT;        
    ENDPROC
ENDMODULE

mkatliar

@VictorAx I tried adding SkipWarn as you suggest, but it does not change the behavior of the program. The program simply stops with the "Kinematics error" message, and the ERROR handler is never called (also no "Hello from error handler!" message on FlexPendant). What am I missing?

xerim

If configuration is not a concern you can turn use ConfJ\Off for singularity issues, for out of reach positions I would verify that the robot can reach the points in RobotStudio prior to execution. 

mkatliar

xerim said:

If configuration is not a concern you can turn use ConfJ\Off for singularity issues, for out of reach positions I would verify that the robot can reach the points in RobotStudio prior to execution. 

Verifying the motion prior to execution is always a good idea. But what I want to do here is to handle unexpected motion errors and notify a supervising PC than an error has happened. 

lemster68

Actually, the CalcJointT function should error if the calculated Jointtarget is out of reach.  If you still do not see it passing into your error handler you might try the RAISE instruction.

xerim

Do you have multitasking? You can restart the system in the background with multitasking

mkatliar

xerim said:

Do you have multitasking? You can restart the system in the background with multitasking

Yes I have multitasking. But how can I automatically detect a condition such as a kinematics error?

xerim

From the Technical Reference Manual

mkatliar

@xerim your example is very similar to what I wrote in my first post. The problem is that it works for division by 0 but does not work for kinematic error.

xerim

You could try to configure a virtual analog output that is connected to the execution error you are experiencing, then create a procedure which restarts the system in the background when that signal is set to high. 

mkatliar

virtual analog output that is connected to the execution error

-- how can I do this?

lemster68

Change your Error handler handler to what follows, more or less.
TEST ERRNO
  CASE 50065:
     TPWrite "blah blah";
     TRYNEXT;
  DEFAULT
     Stop;
     ! Look in program data for ERRNO value, match it with predefined Error numbers
     ! This helps in finding unanticipated errors
ENDTEST

mkatliar

@lemster68 The problem is that the error handler NEVER FIRES in case of kinematic error!

xerim

mkatliar said:

@lemster68 The problem is that the error handler NEVER FIRES in case of kinematic error!

That is because you don't have it set up in the way lemster has suggested. Compare the example code he provided to the code you have in your original post.

lemster68

I did mention in an earlier post that you may need to use the RAISE instruction for the error.  Also,  the best way to troubleshoot such things is to single step forward one line at a time instead of pressing the start button.  Then you can see how the logic evaluates both TRUE or FALSE.

mkatliar

Hello @lemster68,
have a look at step-by-step execution of the program: https://youtu.be/-XQimhLkxCQ

As I did mention before, in the case of kinematic error the program DOES NOT ENTER THE ERROR HANDLER. Therefore it does not matter what you put there.

lemster68

What is the error code 194?

mkatliar

@lemster68 it is division by 0, obviously.

lemster68

I did not look at the values for those variables.  There is no CalcJointT function there, which should throw an error if it is out of range.  I would normally use the step forward button on the virtual TP.

xerim

The internal error handler of the robot takes over when there is no error handler created by the user, which would indicate that your error handler is incorrectly defined. Take a look at page 74 of the Technical Reference Manual - Rapid Overview

mkatliar

@xerim the error handler is correctly defined and works for division by 0.

xerim

Try this:

MODULE MainModule
    
        FUNC bool CanRobReach(robtarget ToPoint,
        PERS tooldata Tool,
        \PERS Wobjdata wobj) 
        VAR jointtarget jdump;

        jdump:=CalcJointT(ToPoint,tool\wobj?wobj);
        RETURN TRUE;
    ERROR
        SkipWarn;
        RETURN FALSE;
    ENDFUNC

    PROC main()
        
        
        CONST robtarget far_away:=[[10000,10000,10000],[0.0208901,-0.980874,-0.19283,-0.016298],[0,0,1,0],[9E+09,9E+09,9E+09,9E+09,9E+09,9E+09]];
        CONST jointtarget far_away2:=[[1000,1000,1000,1000,1000,1000], [9E9,9E9,9E9,9E9,9E9,9E9]];
        
        
        IF CanRobReach(far_away, tool0) THEN
        MoveabsJ far_away2, v100,fine, tool0;
        ELSE
           TpWrite "error caught";
        ENDIF
    
        

    
    ENDPROC
ENDMODULE

lemster68

OK, I made a bit of an oversight.  I took what you said that the error number was, just as it reads and will be written into the error log as such.  BUT, and this is a big but here, Rapid system error numbers are mostly 4 digits some are 3.  The 50065 Kinematic error will go into the motion.  So what will work is code like this:

PROC Routine1()
	MyJointTarget:=CalcJointT(myRobtarget,Tool0);
        Stop;
    ERROR
      TEST ERRNO
        CASE ERR_ROBLIMIT:
          TRYNEXT;
        CASE ERR_OUTSIDE_REACH:
          TRYNEXT;
      DEFAULT:
       Stop;
     ENDTEST
	ENDPROC

This is a very simple example, tested in RS, goes into error handler.  Of course the robtarget is declared way out of reach.

xerim

@mkatliar Were you able to get this to work? 

mkatliar

@xerim @lemster68
Below is the reply that I got from an ABB engineer:

Unfortunately it is not working like you try to do, MoveAbsJ instruction does not throw any errors when trying to travel to out of reach point.
MoveAbsJ can only handle

Usually robots work in their working envelope and never cross the range border. Only collision errors are handled.

You can go around and use function CalcJointT(). CalcJoinT() can throw errors like mentioned below or write Your own error handler.

Please check if GetTrapData instruction is sufficient for you. This instruction should be located in second task to avoid stopping program execution in case of any error in Motion task.

Then you can use SocketCreate or SocketConnect to establish TCP/IP connection between robot controller and PC to exchange data.

So the bottomline is: there is no way to catch a kinematic error and continue the execution of the motion task.