SPTP_REL problem

ALUCAST · January 26, 2021 at 11:27 AM

Hello,

I'm solving small problem with my kuka robot.

Initial A6 angle is 0.

I use SPTP_REL {A6 720} for turning A6 all around twice. Robot stops exactely back at A6 0. But the problem is, that after this motion there is another slight rotation (+-2°). Than it goes via LIN to next point (also with A6 0).

Don't you know what this small rotation means and how to remove it?

Thank you

hermann · January 26, 2021 at 11:34 AM

Are you mixing SPTP and old style LIN ?

ALUCAST · January 26, 2021 at 11:47 AM

Is this problem? I'm quite new at programing, so I don't know. PTP after SPTP_REL would be better?

EDIT: PTP after SPTP_REL didn't help

hermann · January 26, 2021 at 12:32 PM

You should use PTP and LIN or you should use SPTP and SLIN, but not mixing spline (those with S in front) and those without spline.

Second thing: you always should post your real code, don't describe it with flowery words. It makes difference if there is used cdis or not.

ALUCAST · January 26, 2021 at 4:47 PM

OK, I understand, but whatever I use I have same problem. After SPTP_REL (A6 starts and ends in same coordinate 0 - thats correct) A6 makes small rotation 1,2° and than go to P1.

Code

&ACCESS RVP1
&REL 81
&PARAM EDITMASK = *
&PARAM TEMPLATE = C:\KRC\Roboter\Template\vorgabe
&PARAM DISKPATH = KRC:\R1\Program\ALUCAST\SM\SM_2
DEF SM3_9( )
;***** TEST PROGRAM *****
;FOLD INI;%{PE}
  ;FOLD BASISTECH INI
    GLOBAL INTERRUPT DECL 3 WHEN $STOPMESS==TRUE DO IR_STOPM ( )
    INTERRUPT ON 3 
    BAS (#INITMOV,0 )
  ;ENDFOLD (BASISTECH INI)
  ;FOLD USER INI
    ;Make your modifications here

  ;ENDFOLD (USER INI)
;ENDFOLD (INI)

;FOLD PTP P1 CONT Vel=20 % PDAT1 Tool[1]:alucast Base[0];%{PE}%R 8.3.44,%MKUKATPBASIS,%CMOVE,%VPTP,%P 1:PTP, 2:P1, 3:C_DIS, 5:20, 7:PDAT1
$BWDSTART=FALSE
PDAT_ACT=PPDAT1
FDAT_ACT=FP1
BAS(#PTP_PARAMS,20)
PTP XP1 C_DIS
;ENDFOLD

;FOLD LIN p15 CONT Vel=0.2 m/s CPDAT19 Tool[1]:alucast Base[0];%{PE}%R 8.3.44,%MKUKATPBASIS,%CMOVE,%VLIN,%P 1:LIN, 2:p15, 3:C_DIS C_DIS, 5:0.2, 7:CPDAT19
$BWDSTART=FALSE
LDAT_ACT=LCPDAT19
FDAT_ACT=Fp15
BAS(#CP_PARAMS,0.2)
LIN Xp15 C_DIS C_DIS
;ENDFOLD

SPTP_REL {A6 360}

;FOLD PTP p1 CONT Vel=20 % PDAT27 Tool[1]:alucast Base[0];%{PE}%R 8.3.44,%MKUKATPBASIS,%CMOVE,%VPTP,%P 1:PTP, 2:p1, 3:C_DIS, 5:20, 7:PDAT27
$BWDSTART=FALSE
PDAT_ACT=PPDAT27
FDAT_ACT=Fp1
BAS(#PTP_PARAMS,20)
PTP Xp1 C_DIS
;ENDFOLD
END

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**panic mode** · January 26, 2021 at 5:53 PM

hmmm no... you don't...

you say one thing but sample you posted tells different story because you still have mixed motion types.

and you don't understand advance run.

motion without S (LIN, PTP,CIRC) are executed by one motion planner.

motions with S in name are executed by another motion planner.

and every time your program calls for a different motion planner, program stops, bunch of things are reset, then loaded again... etc.

and this transition is not smooth... this is why you were told to not do that.

btw the two motion planners process approximation differently, paths are slightly different etc. and on top of that you are doing transition between PTP and CP motions. even if using same motion planner, your points could cause wrinkle in path. but you chose not to share that even though you were explicitly asked to post your code.

ALUCAST · January 27, 2021 at 2:47 PM

Ok, but if I use all motions with S, I get very same result. My orig program is not important as I have this problem in this simple program too. I understand I cant mix these motions together. So please is there any different possibility how to rotate A6 by 720°C without SPTP_REL? I tried "FOR" function but it is important for me to set acceleration and speed of rotation. I thing I can't set this parameters in "FOR" function. Can I?

Sorry for my lame access, but I'm not very experienced in this and because of COVID I can't attend any training course....Thanks

SPTP_REL problem

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