Another question about move smoothing

RainerFord · April 14, 2025 at 4:21 PM

Hello

There are a couple of points and SPTP movement with approximation between them. The problem is that robot acts strange on the approximation trajectory (I would call that "jerk" but it is not quite so). It seems like robot rise up its speed when it on the approximation trajectory and set the speed back to normal, when on the trajectory. It could be seen on the attached video (at the very start, when the robot starts to rotate A6).
I tried to lower the acceleration and approximation distance, also tried to increase approximation distance but it does not seems to have effect at all...
What can help to smooth the trajectory?

The robot is KR180 R3200-2 PA, KRC5 with KSS 8.7.7

rb.mp4

**panic mode** · April 14, 2025 at 7:04 PM

couple of points could be the problem if they are close to each other and not forming smooth path. i like to eliminate as many points as possible.

RainerFord · April 15, 2025 at 11:45 AM

Well maybe, but the points are quite distant from each other. At least I think so. The distance between the points more than 1.5-2 meters...
About the point locations: You can see them on the attached pic (top view drawn by my shaking hand). So the TCP moves via the black trajectory and increases speed in the red arc. Than it desend the speed back to normal to the point P3. I can agree that the point location is quite far from organising the smooth approximation with the basic parameters. But I still can not understand, why it does not change trajectory close to the green one when I change the approximation distance parameter (thou this is not my option anyway)... The easiest way I think is to move the P2 closely to P1, but it will not work for me cuz the robot falls back from the camera wich takes its shot...

Posting that message I desided to add P4 and watch if it helps.

Despite your recomendation to eliminate points, lol... But I think it could be useful in this case. I will update this post with a results

Leon · April 15, 2025 at 12:33 PM

could you post your actual program? or just that part of it? you say you are using spline's (SPTP). are you using them in a spline block? Details matter.

When it comes to spline i am no expert, some other people here are much more knowledgeable about that then me. so if you post your code they might be able to see what might be causing the problem.

RainerFord · April 15, 2025 at 12:48 PM

I did not use spline block here... Used to apply it only for some kind of complicated motions. Do not think this is the case...

I can definitely post the code. The problem happens in the XHOME point. On the video is the fragment with TRANSPORTATION(#PLACE) called

Code

DEF TRANSPORTATION(COMMAND:IN)
DECL TRANSPORT_COMMAND COMMAND
SWITCH COMMAND
   CASE #HOME 
;FOLD SPTP HOME Vel=60 % HPTP ;%{PE}
   ;FOLD Parameters ;%{h}
      ;Params IlfProvider=kukaroboter.basistech.inlineforms.movement.spline; Kuka.IsGlobalPoint=False; Kuka.PointName=HOME; Kuka.BlendingEnabled=False; Kuka.MoveDataPtpName=HPTP; Kuka.VelocityPtp=60; Kuka.VelocityFieldEnabled=True; Kuka.ColDetectFieldEnabled=True; Kuka.CurrentCDSetIndex=0; Kuka.MovementParameterFieldEnabled=True; IlfCommand=SPTP
   ;ENDFOLD
   SPTP XHOME WITH $VEL_AXIS[1] = SVEL_JOINT(60.0), $TOOL = STOOL2(FHOME), $BASE = SBASE(FHOME.BASE_NO), $IPO_MODE = SIPO_MODE(FHOME.IPO_FRAME), $LOAD = SLOAD(FHOME.TOOL_NO), $ACC_AXIS[1] = SACC_JOINT(PHPTP), $APO = SAPO_PTP(PHPTP), $GEAR_JERK[1] = SGEAR_JERK(PHPTP), $COLLMON_TOL_PRO[1] = USE_CM_PRO_VALUES(0)
;ENDFOLD
CAMTRIG=TRUE
   CASE #PLACE
;FOLD SPTP HOME CONT Vel=30 % PLPDAT2 ADAT ;%{PE}
;FOLD Parameters ;%{h}
;Params IlfProvider=kukaroboter.basistech.inlineforms.movement.spline; Kuka.IsGlobalPoint=False; Kuka.PointName=HOME; Kuka.BlendingEnabled=True; Kuka.MoveDataPtpName=PLPDAT2; Kuka.VelocityPtp=30; Kuka.VelocityFieldEnabled=True; Kuka.ColDetectFieldEnabled=True; Kuka.CurrentCDSetIndex=0; Kuka.MovementParameterFieldEnabled=True; KukaRoboter.Movement.SplineLogicName=ADAT; Trigger[1]=Trigger 1; TriggerPath[1]=-600; TriggerOnStart[1]=FALSE; TriggerDelay[1]=0; TriggerType[1]=ASSIGNMENT; TriggerAssignVariable[1]=CAMTRIG; TriggerAssignValue[1]=TRUE; Trigger[2]=Trigger 2; TriggerPath[2]=-600; TriggerOnStart[2]=FALSE; TriggerDelay[2]=0; TriggerType[2]=ASSIGNMENT; TriggerAssignVariable[2]=READY2GETCORD; TriggerAssignValue[2]=TRUE; IlfCommand=SPTP
;ENDFOLD
TRIGGER WHEN PATH=PTH DELAY=0 DO CAMTRIG=TRUE
TRIGGER WHEN PATH=PTH DELAY=0 DO READY2GETCORD=TRUE
SPTP XHOME WITH $VEL_AXIS[1] = SVEL_JOINT(30.0), $TOOL = STOOL2(FHOME), $BASE = SBASE(FHOME.BASE_NO), $IPO_MODE = SIPO_MODE(FHOME.IPO_FRAME), $LOAD = SLOAD(FHOME.TOOL_NO), $ACC_AXIS[1] = SACC_JOINT(PPLPDAT2), $APO = SAPO_PTP(PPLPDAT2), $GEAR_JERK[1] = SGEAR_JERK(PPLPDAT2), $COLLMON_TOL_PRO[1] = USE_CM_PRO_VALUES(0) C_Spl
;ENDFOLD
;FOLD SPTP PLPOINTAPP CONT Vel=60 % LAPTP Tool[1]:GRIPPER Base[1]:PALLETTE ;%{PE}
   ;FOLD Parameters ;%{h}
      ;Params IlfProvider=kukaroboter.basistech.inlineforms.movement.spline; Kuka.IsGlobalPoint=False; Kuka.PointName=PLPOINTAPP; Kuka.BlendingEnabled=True; Kuka.MoveDataPtpName=LAPTP; Kuka.VelocityPtp=60; Kuka.VelocityFieldEnabled=True; Kuka.ColDetectFieldEnabled=True; Kuka.CurrentCDSetIndex=0; Kuka.MovementParameterFieldEnabled=True; IlfCommand=SPTP
   ;ENDFOLD
   SPTP XPLPOINTAPP WITH $VEL_AXIS[1] = SVEL_JOINT(60.0), $TOOL = STOOL2(FPLPOINTAPP), $BASE = SBASE(FPLPOINTAPP.BASE_NO), $IPO_MODE = SIPO_MODE(FPLPOINTAPP.IPO_FRAME), $LOAD = SLOAD(FPLPOINTAPP.TOOL_NO), $ACC_AXIS[1] = SACC_JOINT(PLAPTP), $APO = SAPO_PTP(PLAPTP), $GEAR_JERK[1] = SGEAR_JERK(PLAPTP), $COLLMON_TOL_PRO[1] = USE_CM_PRO_VALUES(0) C_Spl
;ENDFOLD
;FOLD SLIN PLPOINT Vel=1.2 m/s LLIN Tool[1]:GRIPPER Base[1]:PALLETTE ;%{PE}
   ;FOLD Parameters ;%{h}
      ;Params IlfProvider=kukaroboter.basistech.inlineforms.movement.spline; Kuka.IsGlobalPoint=False; Kuka.PointName=PLPOINT; Kuka.BlendingEnabled=False; Kuka.MoveDataName=LLIN; Kuka.VelocityPath=1.2; Kuka.VelocityFieldEnabled=True; Kuka.ColDetectFieldEnabled=True; Kuka.CurrentCDSetIndex=0; Kuka.MovementParameterFieldEnabled=True; IlfCommand=SLIN
   ;ENDFOLD
   SLIN XPLPOINT WITH $VEL = SVEL_CP(1.2, , LLLIN), $TOOL = STOOL2(FPLPOINT), $BASE = SBASE(FPLPOINT.BASE_NO), $IPO_MODE = SIPO_MODE(FPLPOINT.IPO_FRAME), $LOAD = SLOAD(FPLPOINT.TOOL_NO), $ACC = SACC_CP(LLLIN), $ORI_TYPE = SORI_TYP(LLLIN), $APO = SAPO(LLLIN), $JERK = SJERK(LLLIN), $COLLMON_TOL_PRO[1] = USE_CM_PRO_VALUES(0)
;ENDFOLD
   CASE #PLACE2
;FOLD SPTP HOME CONT Vel=30 % PLPDAT2 ADAT ;%{PE}
;FOLD Parameters ;%{h}
;Params IlfProvider=kukaroboter.basistech.inlineforms.movement.spline; Kuka.IsGlobalPoint=False; Kuka.PointName=HOME; Kuka.BlendingEnabled=True; Kuka.MoveDataPtpName=PLPDAT2; Kuka.VelocityPtp=30; Kuka.VelocityFieldEnabled=True; Kuka.ColDetectFieldEnabled=True; Kuka.CurrentCDSetIndex=0; Kuka.MovementParameterFieldEnabled=True; KukaRoboter.Movement.SplineLogicName=ADAT; Trigger[1]=Trigger 1; TriggerPath[1]=-600; TriggerOnStart[1]=FALSE; TriggerDelay[1]=0; TriggerType[1]=ASSIGNMENT; TriggerAssignVariable[1]=CAMTRIG; TriggerAssignValue[1]=TRUE; Trigger[2]=Trigger 2; TriggerPath[2]=-600; TriggerOnStart[2]=FALSE; TriggerDelay[2]=0; TriggerType[2]=ASSIGNMENT; TriggerAssignVariable[2]=READY2GETCORD; TriggerAssignValue[2]=TRUE; IlfCommand=SPTP
;ENDFOLD
TRIGGER WHEN PATH=PTH DELAY=0 DO CAMTRIG=TRUE
TRIGGER WHEN PATH=PTH DELAY=0 DO READY2GETCORD=TRUE
SPTP XHOME WITH $VEL_AXIS[1] = SVEL_JOINT(30.0), $TOOL = STOOL2(FHOME), $BASE = SBASE(FHOME.BASE_NO), $IPO_MODE = SIPO_MODE(FHOME.IPO_FRAME), $LOAD = SLOAD(FHOME.TOOL_NO), $ACC_AXIS[1] = SACC_JOINT(PPLPDAT2), $APO = SAPO_PTP(PPLPDAT2), $GEAR_JERK[1] = SGEAR_JERK(PPLPDAT2), $COLLMON_TOL_PRO[1] = USE_CM_PRO_VALUES(0) C_Spl
;ENDFOLD
;FOLD SPTP PLPOINT2APP CONT Vel=60 % LAPTP Tool[1]:GRIPPER Base[1]:PALLETTE ;%{PE}
   ;FOLD Parameters ;%{h}
      ;Params IlfProvider=kukaroboter.basistech.inlineforms.movement.spline; Kuka.IsGlobalPoint=False; Kuka.PointName=PLPOINT2APP; Kuka.BlendingEnabled=True; Kuka.MoveDataPtpName=LAPTP; Kuka.VelocityPtp=60; Kuka.VelocityFieldEnabled=True; Kuka.ColDetectFieldEnabled=True; Kuka.CurrentCDSetIndex=0; Kuka.MovementParameterFieldEnabled=True; IlfCommand=SPTP
   ;ENDFOLD
   SPTP XPLPOINT2APP WITH $VEL_AXIS[1] = SVEL_JOINT(60.0), $TOOL = STOOL2(FPLPOINT2APP), $BASE = SBASE(FPLPOINT2APP.BASE_NO), $IPO_MODE = SIPO_MODE(FPLPOINT2APP.IPO_FRAME), $LOAD = SLOAD(FPLPOINT2APP.TOOL_NO), $ACC_AXIS[1] = SACC_JOINT(PLAPTP), $APO = SAPO_PTP(PLAPTP), $GEAR_JERK[1] = SGEAR_JERK(PLAPTP), $COLLMON_TOL_PRO[1] = USE_CM_PRO_VALUES(0) C_Spl
;ENDFOLD
;FOLD SLIN PLPOINT2 Vel=1.2 m/s LLIN Tool[1]:GRIPPER Base[1]:PALLETTE ;%{PE}
   ;FOLD Parameters ;%{h}
      ;Params IlfProvider=kukaroboter.basistech.inlineforms.movement.spline; Kuka.IsGlobalPoint=False; Kuka.PointName=PLPOINT2; Kuka.BlendingEnabled=False; Kuka.MoveDataName=LLIN; Kuka.VelocityPath=1.2; Kuka.VelocityFieldEnabled=True; Kuka.ColDetectFieldEnabled=True; Kuka.CurrentCDSetIndex=0; Kuka.MovementParameterFieldEnabled=True; IlfCommand=SLIN
   ;ENDFOLD
   SLIN XPLPOINT2 WITH $VEL = SVEL_CP(1.2, , LLLIN), $TOOL = STOOL2(FPLPOINT2), $BASE = SBASE(FPLPOINT2.BASE_NO), $IPO_MODE = SIPO_MODE(FPLPOINT2.IPO_FRAME), $LOAD = SLOAD(FPLPOINT2.TOOL_NO), $ACC = SACC_CP(LLLIN), $ORI_TYPE = SORI_TYP(LLLIN), $APO = SAPO(LLLIN), $JERK = SJERK(LLLIN), $COLLMON_TOL_PRO[1] = USE_CM_PRO_VALUES(0)
;ENDFOLD

ENDSWITCH

END

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hermann · April 15, 2025 at 1:21 PM

Quote from RainerFord

Well maybe, but the points are quite distant from each other. At least I think so. The distance between the points more than 1.5-2 meters...
...
Despite your recomendation to eliminate points, lol... But I think it could be useful in this case. I will update this post with a results
...

You have a movement over two identical positions. Before the switch robot moves to xhome and the first movement in the case also is xhome. Eliminate one of them.

Fubini · April 15, 2025 at 1:24 PM

Also check you load data. You change tool for every point which potentially also leads to a load change. Maybe to a false load?

RainerFord · April 15, 2025 at 1:59 PM

Quote from hermann

You have a movement over two identical positions. Before the switch robot moves to xhome and the first movement in the case also is xhome. Eliminate one of them.

I assume you wrong. There are no any moves outside the switch structure. The first xhome movement is under switch, #HOME case.

Quote from Fubini

Also check you load data. You change tool for every point which potentially also leads to a load change. Maybe to a false load?

That was my first assumption. But I'm pretty sure that the tool is the same in all points. And it has the correct load data

UPD:

Also noticed that in the code I posted there are velocities difference between xhome (30%) and other points (60%). To be more clarify: I changed the velocities to see if it helps. On the video all points has 30% velocities.

kalpesh55115 · April 16, 2025 at 3:14 AM

Try to teach the pos i.e. home before you start approximating in same tool and base of place pos. I have seen when on the way when you change tool and base the robot does a bit of jerky moment. You can create a new program from Home with same base and tool and go into palce and see its jerking for testing.

RainerFord · April 20, 2025 at 9:25 PM

So there are no miracles or some secret settings. The problem seems to be solved via the fine tuning of the accelerations in every single point. And also point positions optimizing (such as A6 reorient)

Another question about move smoothing

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