Thanks Fubini, this is exactly what I was looking for. I managed to get hold of the KSS 8.3 Programming Guide and this does indeed have more info on the use of splines (Not in the 8.22 I was using). I have tried CONST_VEL with my test pattern on my KRC4 and it shows me exactly how slow I would have to run to get a continuous movement for my path with the tool being reoriented - you can clearly see how hard the wrist is having to work during the turns. Unfortunately this shows me without any doubt that I will need to keep a fixed tool orientation to be able to execute my required path at a reasonable speed with the much tighter turns required by my path. But it is all usefull info for the future, so thanks again
Posts by ShaunTheSheep
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That's very interesting Fubini, can I ask where you learned about that and if you have any documentation? I have not seen mention of this in the documentation I have. I will be sure to investigate this and let you know.
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Thank Alex for the reply, I have indeed considered slowing the motion to get around this issue. But I don't think I'll get away with it as my test pattern was basically a square with rounded 90 degree corners of a 10mm radius and I had this issue at a moderate speed. However the actual part contains some corners with a 1mm radius which will surely cause me problems unless I run at a crawl which is impractical.
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Thanks to all for their suggestions on this, I have now proved that the issue I was seeing was down to trying to move the tool orientation (which was following the SPLINE path) too quickly which was causing a reduction in velocity. The manual does state that "major reorientation" can cause reduction in velocity, so I ran my test program with a fixed tool orientation and it runs without any reduction in velocity. Although this is not ideal for my application (I would get better results by allowing the tool to follow the path while applying glue) it is more important that I have the constant velocity and be able to make tight curved path changes.
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Thanks for the replies.
SkyFire,
I cant see any additional info in the DAT file file for the taught points vs the offline programmed points:CodeDECL E6POS XP8={X 290.911926,Y 300.000,Z 50.0000,A -0.000756374036,B 15.0000067,C 179.997025,S 2,T 35,E1 0.0,E2 0.0,E3 0.0,E4 0.0,E5 0.0,E6 0.0} DECL FDAT FP8={TOOL_NO 1,BASE_NO 0,IPO_FRAME #BASE,POINT2[] " ",TQ_STATE FALSE}
I don't need to put approximation between SPLINE blocks, it's the movements inside the SPLINE declaration that seem to decel/accel between points - but only when using offline programmed points. Also from one SPL to another SPL point i get this - not just SLIN to SPL.
Eusty,
I will try the SPLINE path with just SPL moves and see how that goes. I have also read that I can add a C_DIS command to the end of an SLIN instruction to approximate the end point - this may also help here. -
Hi Alex, thanks for the reply, I have indeed read the spline section in the manual with particular care to look at the section on reduction of velocity. The method I have used SLIN -> SPL -> SLIN is taken directly from this manual under the replacing an approximated motion with a spline block section.
The part I can't understand is how I can get the desired motion when using taught points but get approximation errors when using hard coded positions (exactly the same points for both methods)
Any help would be much appreciated
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Hi all - first time poster here,
I have a gluing application that reqires a continuous fixed speed path movement, I have been able to get a test program (rectangle with rounded corners) working using LIN/CIRC and C_VEL using hard coded points (actual point data to be taken from CAD model of part to be glued). However I have read that I could use a SPLINE block movement to give better results, so I set about duplicating my test program with a SPLINE. If I teach the points I can get a nice smooth movement, but if I feed the SPLINE block with my hard coded points then the movement is not smooth (decel / accel around each point). I also get the following messages :-KSS01123 Approximate positioning not possible (module TEST, block 76) (=> 1442)
KSS01442 Sequence of instructions that cannot be approximated (module TEST, block 96)Example of KRL code I am using :-
SPLINE
SLIN POINT[1] C_VEL
SPL POINT[2] //Mid point of arc
SPL POINT[3] //End of arc
SLIN POINT[4]
SPL POINT[5]
SPL POINT[6]
SLIN POINT[7]
SPL POINT[8]
SPL POINT[9]
SLIN POINT[10]
SPL POINT[11]
SPL POINT[12]
SLIN START_POS
ENDSPLINE C_SPLCan anyone please shed some light on what I am doing wrong here or point me at some further documentation on the use of SPLINE - the documentation I have does not go into any detail on the use of SPLINE outside of using taught points (Kuka System Software 8.22 - Operating and Programming Instructions for System Integrators)