Posts by Alfredo Iglesias

Thanks for your explanation. I have read the "Read First" section, but it's been a while and I haven't been able to apply all the excellent advice found there. I also gave your post a Like where you mention it hahaha.
It's very difficult to acquire so much knowledge/experience in a short time or to remember so many things. The methodology is the key and the careful work.

I just realized that my Kuka Expert PRO account license has expired a short time ago, and now it's only Kuka Expert Basic =(

Without this tool it's almost impossible to work on KUKA. Best regards

Quote from panic mode

well... you did not mention which one you are trying to use... or what KSS you are working with... or how exactly did you search....

at any rate i am pretty sure your search method is bad. and i already did all i could to make that easier. but lets go over it again:

as the post says take a look at CWRITE manual (one that is for your KSS).

not everything is in one manual. even programming manual for system integrators has limitations. as the READ FIRST says, there are few key manuals. And one should get more - all that you need. And READ FIRST also says where to find manuals. if you types CWRITE in Xpert, you would see them...

btw READ FIRST Also mentions some handy programs, like Everything and AgentRansack. why don't you use them? let computer do the work for you...

if you know part if the file name:

if you don't know or care about manual name, and want to look inside the files:

as yo can see very few hits for CWRITE in system integrator manual...

you KNOW you found the correct manual when you see one with many hits like here:

each search only took seconds:

Everything looked at enture HDD (some 500Gb used) but only inspected file names.

AgentRansack looked only inside KUKA folder, which on this machine is smallish. It looks like a lot of files but that is because i have copy of slimmed down Parts and Docs there. Still it searched throough all of them and listed ones that contain CWRITE.

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Panic. I've been reading the manual. But I can't find any information.

Could you tell me in which manual I can find information about $CMD, regarding the possible FORMATS that can be used?
I know that the manual explains how to enter different FORMATS. But it doesn't specify which $CMDs can be used!

In the example in the manual it only shows "RUN, STOP and CANCEL". I'd like to know what other options can be used. As well as to better understand the meaning of $CMD, what is explained in the manuals is that it is "Management number (handle) for command channel $CMD", but it doesn't explain what CMD is, how are the specific ways of working with that channel, the commands, etc.

Thanks for your time!

Quote from panic mode

take a look at CWRITE manual

Code

DECL STATE_T STAT
DECL MODUS_T MODE
MODE=#SYNC
...
;select program A6()
;to start the program the START-button or
;an external start-signal is needed
IF $FLAG[1]==TRUE THEN
CWRITE($CMD,STAT,MODE,"RUN/R1/A6()")
$FLAG[1]=FALSE
ENDIF
;stop program A6()
IF $FLAG[2]==TRUE THEN
CWRITE($CMD,STAT,MODE,"STOP 1")
$FLAG[2]=FALSE
ENDIF
;cancel program A6()
IF $FLAG[3]==TRUE THEN
CWRITE($CMD,STAT,MODE,"CANCEL 1")
$FLAG[3]=FALSE
ENDIF

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Quote from panic mode

Check schematics. If i recall A1 to A3 share same brake release circuit. However, brakes need to be energized to release. intermittent problem due to faulty wiring would likely be loss of brake power. In other words, brake would be applied in wrong time and axis would fault due to high torque.

It is also possible that issue is in the brake release channel (servo drive) and that brake stays released fir too long. On older products this could be due to sticky relay but similar outcome us plausible in any type of circuit if ut is faulty

Is this the error you are referring to? In what type of manual can I find more information about this error KSS15016? Or a troubleshooting guide?

In solution 2, it indicates changing a variable or parameter in a file, but it does not indicate what they are. I found this message in the SafeConfiguration manual, am I looking correctly?

Thanks for your time!

Quote from CMENDES

But I have one question,. The defined delay its only valid for the motion between the two points? Or if the delayed time is bigger then the time that the robot will take to do the motion between these two points its also valid?

You read the examples in the documentation of:

KUKA System Software 8.X
Service and programming instructions for integrators
systems.
Section: 10.11 Switching actions related to the trajectory (=Trigger)

As specified and exemplified in the manual, the time must be within the 2-point interval.

Did you consider using PATH? . There the manual specifies that it is possible to bypass other points.
(TRIGGER WHEN PATH = Path DELAY = Time DO Instruction PRIO=Priority)

In the manuals there are very good examples of how to use these functions with drawings.

Good luck

Quote from cnccreations

I have a 240kg payload robot (not AA). With axis 2 tilted forward around 30deg from vertical, and axis 3 approximately horizontal (so robot reaching forward but not fully outstretched) adding 60kg (around 25% of the robots max payload) to the rollface will result in the rollface moving down approximately 1mm (a combination of sponge in the gearbox and flex in the arm). On a non-AA robot, I believe this will be the same regardless of what you set the load data to, as I don't think the controller compensates static positions based on the load. The load ID is important for dynamic movement though.

And in relation to your original question, on a 90kg payload robot, with a 20kg gripper and upto 20kg part, you could probably program your pick positions/frame with the gripper holding a 10kg part (middle of the range giving a combined mass of 30kg) and not run into any major accuracy issues over the +- 10kg range. Having something to approximate the load parameters based on the estimated part weight would be nice if possible but if your movements aren't too fast and your gripper keeps the part close to the rollface basing it on a 30kg weight may be adequate.

According to what I have learned in Dynamic and Kinematic Robotics (theoretical) and I think it is mentioned by the engineer in the video. The internal models do compensate for the "spring" deformations that occur in each link. That's why I think the engineer says at the end of the video that if you have a robot with a capacity of 120kg and no load or a load of less than 30% is placed on it. Some accuracy will be lost. That's why he then explains that Kuka should be sent to "recalibrate", because they have access to change the Internal Models of the robot.

Also something interesting that he hints at, which is calibration with a laser tracker, he hints that if you calibrate the robot you can improve it a lot, but you will not be able to access the data from the Internal Model of the robot, in order to leave it even better calibrated.

That is why I asked you my question, based on your experiences, that you have lost so much accuracy when using large robots with loads of less than 30%.

Thank you for sharing your experiences!

Quote from panic mode

when robot is using small payload, and it is not told what the mass of the payload is, results obtained by Load Data Determination are poor.

Sure, I understand that, but I'm talking about using a robot without Load Data Determination. Just load the data from the tool by typing and assuming that it is fairly accurate.

My question refers to the behavior of a robot without AA, if the weight of the tool is below 30% of the nominal load (the load to which the kinematics and dynamics the robot is calibrated from the factory. "the kuka gym ") accuracy is greatly lost. This is what I understand the engineer is implying in the video, but they are talking about robots with AA. (minute 55:44)

What happens, would we expect the accuracy to lose too much (go from 0.7 to 1 or 2 mm for example)?

You Panic Mode talked about a case similar to what I am trying to refer to. But in your case, you demonstrate the problem of not loading the data correctly and the consequence in the engines. But it does not specify whether using a large robot to move a small load decreases the factory robot's own accuracy.

Quote from SkyeFire

Post

RE: MANY DIFFERNT LOADING DATA FOR A SINGLE TOOL

If your program uses Inline Forms (ILFs), then you must alter LOAD_DATA[ x ]. If your motions are "raw" KRL, you need to alter $LOAD.

Inside every ILF motion command is a call to BAS.SRC which, among other things, sets $ACT_TOOL to the number of the tool selected in the ILF, and then sets $LOAD = LOAD_DATA[$ACT_TOOL]

TOOL_DATA and LOAD_DATA are parallel arrays in $CONFIG.DAT. When an ILF motion is using Tool 11, the contents of TOOL_DATA[ 11 ] are assigned to $TOOL (the "live" TCP, XYZABC…

SkyeFire

September 17, 2021 at 3:47 PM

Short version: you can rewrite $LOAD or any member of LOAD_DATA as you need, from inside your program.

The more accurate the $LOAD value is, the better. But in the real world, +/- 5% is probably pretty typical -- even if you run KUKA.LoadDetermination, there's always a margin of error. And LoadDetermination loses accuracy fast once the payload is below 30% of the robot's rated payload.

The amount of $LOAD error needs to be considered proportional to the robot's payload. An error of 20kg would be nearly irrelevant to a KR500 (4%), but very important to a KR60 (33%).

The CoG and Inertia values are just as important as the mass, especially as the robot moves faster. A 20kg payload mounted far enough from the wrist can actually overload a KR60 due to the moment arm of that distance.

I don't think you can use LOAD_DATA or $LOAD to detect a dropped part -- you'd be better off using direct sensors on the gripp

Continuing with this thread.

Here is a public link to a presentation by a KUKA engineer. It is about absolute accuracy robots.

Understanding Robot Absolute Accuracy Webinar

Many robotic applications require high positional and path accuracy. These include machining, non-destructive testing, and any application that uses offline ...

www.youtube.com

I have a question at minute 55:44. According to your experience or knowledge, in robots that do not have absolute accuracy AA.
Is it correct to assume that working with a tool that weighs less than 30% of the nominal load will bring significant accuracy problems?
Or is this only considered for AA robots?

I am not referring to the accuracy error when loading the weight values!

Quote from panic mode

that is not the error... and you are missing the point...

if you want good results you need to do things right. documentation and previous replies have covered pretty much everything one need to know. measuring location of a point in space requires certain things and it is unclear if you meet those prerequisites.

one of them is that robot need to be move sufficiently. if i understand correctly that is something you explicitly tried to avoid - not sure why. if the flange of the robot does not move much between points, your TCP calculation will suffer. follow the instructions...

Yes you are right.
I decreased the angles between points, because I saw that the error shown on the screen also decreased. But that made the robot not move enough. Now that I understand the concept better, I am going to apply all these details as best I can.

Thanks for your time!

Sorry if I wasn't clear enough. I was only able to upload 2 images. The measurements are in the following image. The ones I mentioned above were approximate, I don't have tools to accurately measure my TCP.

Regarding the explanation and the image, thank you. As I then interpret the error shown in the window, it is the average vector distance of the points. Not the line intersection error (TCP). That is why by decreasing angles one can see that the vector error of distances between points decreases!, but this does not mean that the robot is correctly calculating the real intersection of the TCP.

Now…. Why doesn't it directly show you the TCP intersection error in the window?

Thank you for your answers. (Panic, if it is 8.2.16, type wrong)

Indeed, I managed to reduce the error from 3mm to 0.31mm. With the long TCP. Try, as you mention, I put a seal close to the FLANGE as a test and it is much easier to achieve a TCP error below 1mm.

I achieved this calibration of 0.3 on my TCP of my long tool repeatedly, using 2 highly tuned screws. And within the 4-point procedure, I went back and corrected the points. Indeed, it is best to reduce the angles to a minimum, as long as the vector coordinates between points are never less than 8mm. It was tedious but I was able to get it down. (I leave a photo)

I calibrated the angles with the method of 2, but I have not been able to really rotate at 1 point of the exact TCP, the rotations are displaced, I did this with a comparator probe (and my TOOL TCP has the Z axis in the direction of the torch ). Today I am going to try other methods to correct the angles of the TCP.

Now in a LINE command between 2 points close to the working limits (with non-constant orientation) I manage to follow a line with an error of 1.5mm. I have to try to lower it to 0.5.

Today I am going to make the last attempt to leave the TCP as best I can, otherwise I will fall back on shortening the BRECK (tool support). I created this tool with this distance, trusting the load distribution table, but they are two different things: Kinematics and Dynamics. There I think my mistake was, I'm trying to bring the robot closer to the material but I think I'm going to have to bring the material closer to the robot now.

I still do not understand how in any manual (according to everything I have read), nor in my career that I studied, they explain the problem of moving away from the Original TCP, I understand that it is logical, if the robot approves a repeatability in the FLAG of -+ 0.06mm, if I move away, by Pythagoras, the error will amplify. Is this only explained in the paid courses? hahahahahaha.

Quote from panic mode

make sure that robot is anchored properly on a solid foundation. if you are measuring TCP while robot is on a flimsy wooden skid or just sitting not-anchored on the floor you can expect bad result. if robot is not anchored, you or someone else can get hurt badly and robot can be damaged.

make sure that tool is actually attached correctly. this works only if tool is rigid and secured properly. loose or flexing tool or tool that is attached on something that is not rigid (cylinder etc.) is not good.

and make sure your TCP is not 2 meters from the robot flange. the closer the better... for small robot 100-150mm should be the goal. larger robot up to 300mm or so. keep it close to flange if you want accuracy.

next make sure to have a good point on the tool. something with a sharp point. that could be a TCP. if your TCP is not on a solid point, you need to create a jig with solid TCP point. if your tool is an array of vacuum cups (ie. no sharp point anywhere) or it is for whatever reason unwieldy, you need to have an option to mount temporary pointer. normally this is a scribe-tool with threaded end for easy removal. note that although this pointer is removable, it is now part of the robot supply so that TCP verification and recalibration can be performed.

next you need a stable (solid) reference point. this will be used during tool calibration and it can be any point in space that robot can easily reach with different tool orientations. this can be temporary bit it has to stay in one place during calibration. preferably this too would be a pointer. i prefer to use countersink magnet or base of a magnetic hook and replace hook with a pointer or just bend the hook out and sharpen it. this is cheap, easy to attach pretty much anywhere and can be easily removed.

it does not even need to be straight... and who does not like magnets...

if you cannot get both TCP and reference point pointy, that is ok. as long as one of them has sharp point you are in luck.

using this one should easily get 0.1mm error or so in one or 2 tries. my eyes are not quite what they used to be but i can still easily do 0.3mm in first pass and in no time.

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Hello Panic, how are you?

I wanted to consult, for a robot (KR 60L Jet, KRC4, kss 8.1.16,I am integrating this robot with a hypertem cutter and a THC height control system) ) with a plasma cutting tool at a distance of Z= 700 mm, Y=340 x=170 from the flange approximately.
Is it possible to calibrate the TCP below an error of 3mm? I can't achieve it, I have tried with the magnet, using screws with tips, different places, etc. But I can't go below 3mm with the 4-point method =(.

Because in no manual does it explain or give a KuKa graph on the increase in error when moving away from the flange. Just as if it does it with the load!

I have corroborated all the tips you mentioned above and I can't get the error down. In addition, I already adjusted the robot with a dial indicator. And with that TCP of 3mm error I have deviations in the LIN of those 3mm, I need to be able to make lines of a maximum of 1mm error.

Any recommendation? Thanks for your time.

Hello everyone,

Can anyone recommend a program for me besides the ones mentioned earlier, that can be used to make a copy of the HDD from a KRC4? Did the same program work for restoration as well?

Regards

Hello guys. First of all, thank you "Panic Mode" for your contributions to this forum.

I wanted to ask you if it's possible for the manuals and documentation of the robot to be stored, besides the CDs, on the robot's hard drive. Is this possible? The WoV installer with its corresponding version, I suppose, wouldn't be there either? I have searched through the teach pendant but I cannot find files like those on the CDs.

This is a doubt because it seems logical to me that robots with large disks could store this information instead of having CDs/USBs that can get lost.

Greetings

Thanks friends.

I managed to find the fault, if it was the power supply, the strange thing is that it does not mark any fault. It seems that the 5V continuous power component to the CPU becomes alternating or noisy.

I have a fanunc S-420iW power supply code A16B-1212-0871/13C and it works with that.

The original source is A16B-1212-0871/12C

My question now is, will it not have long-term failures? Are the fonts compatible?

In the RJ-2 maintenance manual that I have, only the codes up to A16B-1212-0871 appear.

If you can leave me with that peace of mind that I am placing this other power supply unit correctly, the /13C?

Thanks for your time

Hello partners

I will tell you about an experience I had with a Fanunc RJ-2 S-420I. As the title describes, he had many unexpected behaviors and they were not repeated. The failures always alternated. The Main CPU changed faults, sometimes the robot turned on without problems, then the teach pandat hung up, we changed the teach pandat, cable, it did not let it enter Boot Mode, sometimes it did but the teach froze, etc etc.

In short, the power unit did not indicate errors. But it seems that some defective capacitor or component generated bad supply voltage for the CPU and caused these unexpected behaviors.

We changed the power unit and I manage to run everything correctly.

Later we will measure the failing power supply, with an oscilloscope, and try to change some basic electronic components, if we find the specific failure of the component, we will follow the thread.

Regards, good luck in your work and hugs

Español

Hola compañeros

Les comento una experiencia que tuve con un Fanunc RJ-2 S-420I. Como describe el titulo, tubo muchos comportamientos inesperados y no se repetían. Siempre alternaban las fallas. La Main CPU cambiaba de fallas, a veces prendía el robot sin problemas, luego se colgaba el teach pandat, cambiamos teach pandat, cable , no dejaba entrar en Boot Mode, a veces si pero se congelaba el teach, etc etc.

En fin, la unidad de potencia, no indicaba errores. Pero parece que algún capacitor o componente defectuoso, generaba mala tensión de alimentación para la CPU y hacia estos comportamientos inesperados.

Cambiamos la unidad de potencia y logro andar todo correctamente.

Mas adelante mediremos la fuente de alimentación que falla, con un osciloscopio, e intentaremos cambiar algunos componentes básicos electrónicos, si encontramos la falla en especifico del componente, seguiremos el hilo.

Suerte y abrazos

Hello colleague.

I have an s420 iF for educational purposes. And the same problem has arisen, I cannot enter the Boot Monitor.

Check the TP cable, it is OK. The strange thing is that sometimes, it allows me to enter BootMonitor but after 10 seconds, the TP is stuck and does not respond.

In the manuals I have, I can't find a troubleshooting guide directly associated with this problem.

In my case, the LIGHTS that the CPU turns on are 4 green and 3 red. Sometimes it changes to the 2 red ones on the left side.

It is a fault that I cannot identify because it usually changes states, it drives me crazy. ha ha ha ha ha ha

It is very similar to the fault that they have here.

Could they fix it?