Using a IRB6600-175/2.8 to stack varying lengths of steel tubes, which means that we have a wide tool on it. I set up the tool as best I could using all the parameters I got from SolidWorks (which I used to design it) for weight, COG and tool offsets and such. The problem I have is if I go more then 24 feet wide on the tubes, axis 6 overcorrects worse and worse till it fire an emergency stop and says collision. We pick up the tubes in the center but it still starts shaking. In the manual it tells you where to go in ABB's website for a calculator to get the settings but I can't find it. Is there a way to adjust one axis so that it isn't as sensitive? Or can one adjust the ramp time on that axis so it slows down sooner and doesn't overcorrects?
Axis 6 overcorrecting
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Lauyder -
November 17, 2019 at 12:46 AM -
Thread is Unresolved
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S4 or IRC5 ?
Have you tried running LoadID ?
AccSet will allow you to decrease acceleration / acceleration, but it's global and not just Ax6.
SpeedLimAxis (IRC5) will let you limit the speed of an axis (not quite what you're asking for, but still).
You may also play around with setting a higher payload than what you actually use and/or an inertia in the tool / loaddata.
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Do you change the payload data on the fly, based on the different weights of the bars?
I would suspect that the root issue is that the longer bars increase inertia faster than they increase the actual payload mass. If you change the mass and inertia values based on which bar the robot is picking up, that should let the path planner predict how much it needs to reduce velocity and/or acceleration for the longer bars.
Failing that, reducing the motion commanded speed and acceleration dependent on which bars are being carried is probably the next best option.
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From the image it looks to be a S4C or C+ control.
Another possibility depending on cycle time, etc, would be to use Soft Servo to make the axis more compliant
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I wouldn't rule out a mechanical issue with a robot this age and the awkward loading. Has the robot been PM'd lately? If you're comfortable in doing this; try jogging axis 5 so axis 6 faceplate is parallel to the ground and the load on axis 6 is balanced. Have a second person carefully release axis 6 brake using the buttons on the side of the robot and manually move axis 6 at different speeds thru most of its range and 'feel' for any roughness in the axis 6 RV reducer.
To rule out an issue with the servo amplifier, try swapping the 2 amplifiers on the right (A1 & A2) to see if the problem moves to axis 4.
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There's also the question of harmonics. When picking up the larger pipe lengths, how much unsupported pipe is "flapping in the breeze," out past the ends of the end effector? It's possible that, past a certain length, the amount of flapping/bouncing pipe is creating feedback into Axis 6 that, to the robot, feels like it's being jerked around. I think the solution would still be to reduce acceleration or setting correct inertia, but this might be an easily visible symptom of the problem.
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The inertia value in your tooling and payload ix, iy and iz need to be set. I have dealt with this on project where the robot spazzed out because the inertia was not set correctly. Look for LoadID system routine. If you have it, use it to set the tool and gripload (Payload). It will make a huge difference.
Matt
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Make sure that you have the correct armloads, (if any) entered BEFORE using loadid. If you get everything correct and you do not have any mechanical issues, you can also use Tuneservo for exceptionally long loads. Read up on it in the system parameter manual.
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An extension to Lemster's excellent Tune Servo advice, if & when followed, would be to use the Tuning procedure in the Application manual Additional axes and stand alone controller in the Tuning chapter. Even though that manual was probably not created until RW 5, the RAPID code examples should be usable in RW 4.X.
E.g.:
FOR i FROM 0 TO 40 DO
per_Kv:=100+10*i;
Kv:=1*per_Kv/100;
TPErase;
TPWrite "per_Kv = "\Num:=per_Kv;
TPWrite "Kv = "\Num:=Kv;
TuneServo ROB_1,6,100\Type:=TUNE_KP;
Moves, etc. ...
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I want to get this Robot serviced/checked out, ie preventative maintenance since its a used older machine. Got a quote from ABB to have a tech come out, but was wondering if there is a second party company that does that kind of stuff. One that I'm thinking about is Robotworx. do they do things like that?
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There are many, many companies servicing robots besides the OEMs.
I would contact Canadian immigration before try to get someone from the states as they can be very strict about some of the work that can be done by foreign businesses.
If you can find someone closer, it should save money on travel costs.