Odd Step Behavior

Robo_Eng_13 · May 14, 2019 at 7:47 PM

This has occurred at least twice in the last few months, and i am at a loss for what could be causing it.

Program behavior in and out of STEP mode is completely different, but only rarely.

Occurrence #1: STEP Mode, robot moved as programmed, through the end of a weld, and then into a retreat path. RUN Mode, robot finished weld, then took off close to 90 degrees from the anticipated retreat path, crashing into the part and fixture. This happened a while back, and i do not have any further details at this point.

Occurrence #2: STEP Mode, robot moved as programmed, through the end of a weld, and then into a retreat path. RUN Mode, robot finished weld, then faulted out, reporting a Limit Error on G:1, A:1. G:1,A:1 was at an angle of about -95 degrees both before and after the problem move, and the axis limit is -170 to +170, so well within limit. This occurred today. The weld is an Arc move, the retreat is a J move. I tried replacing the J move with an L move, changing the end type between CNT0, CNT50, CNT100, and FINE, changing move speed, breaking up move, changing angles, adding a wait, and changing the order of the weld termination parameters. Nothing would make it run through the end.

My only remaining suspicion is this. Both times, a technician had been responding to a different issue, and was manually finishing the program. They were not called due to this issue, which indicates to me that the issue did not exist when it was running as normal. Is there anything that could possibly cause this behavior? Has anyone seen something like this before?

Hazard · May 14, 2019 at 7:59 PM

I saw something similar to this once when a robot tried to move to a point programmed in user frame 0 while another user frame was still active.

Robo_Eng_13 · May 14, 2019 at 9:19 PM

Were you able to overcome this issue? How did you diagnose the problem to begin with? I will keep this in mind for the next time we see this, and hopefully be able to test a couple of diagnostic ideas and potential solutions. Maybe re-asserting the UFrame before the retreat move?

HawkME · May 14, 2019 at 9:43 PM

What is the termination (cnt, fine) for the last of your arc movements?

It may help if you post the code for that program.

Robo_Eng_13 · May 14, 2019 at 9:50 PM

The termination type at the end of the weld is (i believe) FINE, but tomorrow i will take a text backup of the program and post it.

Robo_Eng_13 · May 15, 2019 at 2:23 PM

Here is the problem code. Attached and included. In STEP i am able to move forward and backward from line 42 to line 48 without issue. In RUN mode, it executes line 43, then faults out on line 47.

Code

/PROG  MRHP6200_AUG_JS
/ATTR
OWNER		= MNEDITOR;
COMMENT		= "DPF S2 360 Welds";
PROG_SIZE	= 2501;
CREATE		= DATE 18-12-27  TIME 22:33:54;
MODIFIED	= DATE 19-05-15  TIME 00:54:10;
FILE_NAME	= MRMHP620;
VERSION		= 0;
LINE_COUNT	= 49;
MEMORY_SIZE	= 2805;
PROTECT		= READ_WRITE;
TCD:  STACK_SIZE	= 0,
      TASK_PRIORITY	= 50,
      TIME_SLICE	= 0,
      BUSY_LAMP_OFF	= 0,
      ABORT_REQUEST	= 0,
      PAUSE_REQUEST	= 0;
DEFAULT_GROUP	= 1,*,1,*,*;
CONTROL_CODE	= 00000000 00000000;
/APPL
  ARC Welding Equipment : 1,*,*,*,*;
/MN
   1:  UFRAME_NUM=4 ;
   2:  UTOOL_NUM=2 ;
   3:   ;
   4:J PR[1] 80% FINE    ;
   5:  !Feature Approach ;
   6:J P[1] 100% CNT50    ;
   7:J P[2] 100% CNT50    ;
   8:L P[3] 1000mm/sec FINE    ;
   9:   ;
  10:   ;
  11:  WAIT R[60]=0    ;
  12:   ;
  13:  !Marmon Band ;
  14:  SKS_JOB (1,22,4) ;
  15:   ;
  16:A P[4] 5000cm/min FINE
    :  Weld Start[1,1] Offset,PR[81] COORD    ;
  17:A P[5] 60.0inch/min CNT100 Offset,PR[81] COORD    ;
  18:A P[6] 60.0inch/min CNT100 Offset,PR[81] COORD    ;
  19:A P[7] 60.0inch/min CNT100 Offset,PR[81] COORD    ;
  20:A P[8] 60.0inch/min CNT100 Offset,PR[81] COORD    ;
  21:A P[9] 60.0inch/min CNT100 Offset,PR[81] COORD    ;
  22:A P[10] 68.0inch/min FINE Offset,PR[81]
    :  Weld End[1,1] COORD    ;
  23:  //WAIT    .20(sec) ;
  24:   ;
  25:L P[11] 50mm/sec CNT25    ;
  26:   ;
  27:  !Feature Retreat ;
  28:J P[12] 100% CNT50    ;
  29:   ;
  30:  !Feature Approach ;
  31:J P[13] 100% CNT50    ;
  32:   ;
  33:  WAIT R[61]=0    ;
  34:   ;
  35:  !Flare Band ;
  36:  SKS_JOB (1,22,4) ;
  37:A P[14] 5000cm/min FINE
    :  Weld Start[1,1] Offset,PR[80] COORD    ;
  38:  Weave Sine[2] ;
  39:A P[15] 55.0inch/min CNT100 Offset,PR[80] COORD    ;
  40:A P[16] 55.0inch/min CNT100 Offset,PR[80] COORD    ;
  41:A P[17] 55.0inch/min CNT100 Offset,PR[80] COORD    ;
  42:A P[18] 55.0inch/min CNT100 Offset,PR[80] COORD    ;
  43:A P[19] 60.0inch/min FINE Offset,PR[80]
    :  Weld End[1,1] COORD    ;
  44:  WAIT    .20(sec) ;
  45:  Weave End ;
  46:  !Feature Retreat ;
  47:J P[20] 100% CNT100    ;
  48:J P[1] 100% CNT80    ;
  49:J PR[1] 100% FINE    ;
/POS
P[1]{
   GP1:
	UF : 4, UT : 2,	
	J1=   -90.000 deg,	J2=   -20.000 deg,	J3=      .000 deg,
	J4=     -.000 deg,	J5=  -130.000 deg,	J6=     -.000 deg
   GP3:
	UF : 0, UT : 2,	
	J1=     0.000 deg,	J2=   -43.238 deg
};
P[2]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =  -146.041  mm,	Y =  -497.543  mm,	Z =   297.474  mm,
	W =    -2.697 deg,	P =    67.115 deg,	R =   161.663 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .012 deg,	J2=  -195.601 deg
};
P[3]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =  -129.634  mm,	Y =  -610.247  mm,	Z =   207.844  mm,
	W =     4.401 deg,	P =    69.051 deg,	R =   134.564 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .016 deg,	J2=  -195.598 deg
};
P[4]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   136.957  mm,	Y =  -648.613  mm,	Z =   133.603  mm,
	W =   -58.269 deg,	P =    48.216 deg,	R =    69.454 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .022 deg,	J2=  -195.599 deg
};
P[5]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   103.370  mm,	Y =  -647.985  mm,	Z =   110.505  mm,
	W =    23.201 deg,	P =    58.035 deg,	R =   169.280 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .017 deg,	J2=  -181.799 deg
};
P[6]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   107.049  mm,	Y =  -648.039  mm,	Z =   110.686  mm,
	W =    22.878 deg,	P =    57.411 deg,	R =   168.333 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .014 deg,	J2=  -112.877 deg
};
P[7]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   105.538  mm,	Y =  -649.148  mm,	Z =   109.845  mm,
	W =    21.215 deg,	P =    50.660 deg,	R =   166.851 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .019 deg,	J2=   -50.629 deg
};
P[8]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   103.075  mm,	Y =  -648.933  mm,	Z =   106.798  mm,
	W =    12.477 deg,	P =    53.633 deg,	R =   159.217 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .019 deg,	J2=    34.170 deg
};
P[9]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =    99.675  mm,	Y =  -647.195  mm,	Z =   109.325  mm,
	W =     4.001 deg,	P =    51.308 deg,	R =   152.502 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .012 deg,	J2=   115.744 deg
};
P[10]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, -1',
	X =    91.139  mm,	Y =  -646.922  mm,	Z =    97.415  mm,
	W =    30.111 deg,	P =    39.019 deg,	R =   168.702 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .014 deg,	J2=   139.311 deg
};
P[11]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   129.657  mm,	Y =  -637.532  mm,	Z =   153.933  mm,
	W =    11.163 deg,	P =    26.128 deg,	R =   158.419 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .003 deg,	J2=   142.342 deg
};
P[12]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   165.894  mm,	Y =  -654.024  mm,	Z =   251.278  mm,
	W =     2.085 deg,	P =    29.043 deg,	R =   153.881 deg
   GP3:
	UF : 4, UT : 2,	
	J1=     0.000 deg,	J2=   143.662 deg
};
P[13]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   507.958  mm,	Y =  -645.752  mm,	Z =   151.005  mm,
	W =   -11.374 deg,	P =    51.596 deg,	R =   -46.618 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .017 deg,	J2=   197.058 deg
};
P[14]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   208.667  mm,	Y =  -535.413  mm,	Z =   148.511  mm,
	W =    -5.369 deg,	P =    58.055 deg,	R =   -42.223 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .061 deg,	J2=   175.751 deg
};
P[15]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   250.118  mm,	Y =  -534.587  mm,	Z =   138.902  mm,
	W =     4.887 deg,	P =    34.926 deg,	R =   -44.289 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .058 deg,	J2=   101.477 deg
};
P[16]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   249.800  mm,	Y =  -533.946  mm,	Z =   138.768  mm,
	W =     4.893 deg,	P =    34.929 deg,	R =   -44.279 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .068 deg,	J2=    22.988 deg
};
P[17]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   250.634  mm,	Y =  -535.179  mm,	Z =   141.192  mm,
	W =     4.894 deg,	P =    34.932 deg,	R =   -44.284 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .069 deg,	J2=   -91.817 deg
};
P[18]{
   GP1:
	UF : 4, UT : 2,		CONFIG : 'N U T, 0, 0, 0',
	X =   250.331  mm,	Y =  -534.826  mm,	Z =   140.947  mm,
	W =     4.894 deg,	P =    34.932 deg,	R =   -44.284 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .071 deg,	J2=  -136.275 deg
};
P[19]{
   GP1:
	UF : 4, UT : 2,	
	J1=   -95.050 deg,	J2=    53.865 deg,	J3=   -53.759 deg,
	J4=   -34.663 deg,	J5=   -59.639 deg,	J6=    75.001 deg
   GP3:
	UF : 4, UT : 2,	
	J1=      .037 deg,	J2=  -154.305 deg
};
P[20]{
   GP1:
	UF : 4, UT : 2,	
	J1=   -95.090 deg,	J2=    45.531 deg,	J3=   -47.598 deg,
	J4=   -24.840 deg,	J5=   -51.298 deg,	J6=    71.015 deg
   GP3:
	UF : 4, UT : 2,	
	J1=     0.000 deg,	J2=  -152.712 deg
};
/END

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scotty · May 15, 2019 at 3:13 PM

Try to put L P[19] before line 47.

HawkME · May 15, 2019 at 3:52 PM

Step mode treats all movements as FINE. Have you tried changing changing Line 47 and 48 to Fine? Also I see line 49 is a PR. Are you sure that PR was taught in the same User and Tool frame as your other points, or is it in joint representation?

Robo_Eng_13 · May 15, 2019 at 4:46 PM

Quote from HawkME

Step mode treats all movements as FINE. Have you tried changing changing Line 47 and 48 to Fine? Also I see line 49 is a PR. Are you sure that PR was taught in the same User and Tool frame as your other points, or is it in joint representation?

I did try changing 47 to FINE, still no luck. And there were no issues from 47 to 49, nor from start to 43. Just from 43 to 47. So, i don't THINK the PR can be related, but i guess it is possible.

Quote from scotty

Try to put L P[19] before line 47.

The next time i have access, i will try this. It is a good thought for a solution, although it still does nothing for explaining why on earth this is happening.

Hazard · May 15, 2019 at 7:47 PM

How far does the offset in PR[80] move it? Will it move ok from P[19] to P[20] without the offset in P[19]? Does it pass through singularity in the motion? Have you tried an intermediate point between P[19] and P[20]?

Robo_Eng_13 · May 15, 2019 at 7:51 PM

Quote from Hazard

How far does the offset in PR[80] move it? Will it move ok from P[19] to P[20] without the offset in P[19]? Does it pass through singularity in the motion? Have you tried an intermediate point between P[19] and P[20]?

PR[80] is actually all 0's. I believe it was an artifact of a previous attempt at program commonization. But beside that, i did try to place intermediary points between P[19] and P[20]

Odd Step Behavior

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