Author Topic: Collision detection command  (Read 1343 times)

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Offline tianxiang84

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Collision detection command
« on: March 19, 2018, 09:36:40 PM »
Dear FANUC expert,

We have a code here written by a distributor. There is a line "COL GUARD ADJUST 120".

I am told it is detection of collision and that number 120 is relative to the force sensitivity. But can any one tell me more about what that 120 mean exactly? Like what's its range (from 0 to some value?) and what to expect if I tune this value smaller or larger?

Thank you.

Regards,
Tianxiang

Offline HawkME

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Re: Collision detection command
« Reply #1 on: March 19, 2018, 11:02:10 PM »
The sensitivity ranges from 0-200.

100 is default. The higher the number, the more sensitive it is to disturbances.

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Offline pdl

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Re: Collision detection command
« Reply #2 on: March 19, 2018, 11:43:49 PM »
Be warned, collision guard is extremely dependant on having an accurate payload defined in your payload schedules.

Offline Atinder

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Re: Collision detection command
« Reply #3 on: March 20, 2018, 11:08:31 AM »
If your robot is not operating near any machinery or if there is a lot of workspace for your robot or your taught path has no obstacles nearby and you know that your robot won't collide anywhere you can even disable Collision Detection. To do so go to Menu>> Setup>>F1[Type]>> Col Guard.

Offline pdl

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Re: Collision detection command
« Reply #4 on: March 20, 2018, 08:30:06 PM »
you can even disable Collision Detection

I can't think of one logical reason why you would ever want to do this.  I can think of several reason why you would not do this though...

Offline stare284

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Re: Collision detection command
« Reply #5 on: March 21, 2018, 09:41:11 AM »
you can even disable Collision Detection

I can't think of one logical reason why you would ever want to do this.  I can think of several reason why you would not do this though...

We had to do this Monday due to a reducer failing.
Replacement reducer is on order but will not arrive for another week or so and the machine needs to run so turning off collision detect is the only way to keep production running as usual.

Offline Atinder

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Re: Collision detection command
« Reply #6 on: March 21, 2018, 12:08:11 PM »
you can even disable Collision Detection

I can't think of one logical reason why you would ever want to do this.  I can think of several reason why you would not do this though...
In some of my applications with the Injection Molding Machines, I have very limited space to work with and every time I program it and keep the collision guard enabled it will keep on going to alarm even if I reduce the sensitivity or even if the robot is not even close to hit anything. So for some of my applications I have to keep it disabled to reduce downtime.

Fair enough pdl or not.What do you say?

Moreover, if you can't think of any reason to disable it, that's totally fine but I thought I can work with this option disabled and even that's totally fine. That is the reason Fanuc gives you two options with software- Enable or Disable, use it according to your need.
« Last Edit: March 21, 2018, 01:25:32 PM by Atinder »

Offline alive15

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Re: Collision detection command
« Reply #7 on: March 21, 2018, 04:34:01 PM »
Need to be careful though, if the robot decides not to follow the program and goes whichever way, it can cause severe equipment damage or injury to someone.

Offline nutcase511

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Re: Collision detection command
« Reply #8 on: October 05, 2018, 03:25:15 PM »
If your reducer is failing, then I can see why, under pressure to produce, you would disable it TEMPORARILY.  It's a horrible idea to leave collision detect off though.  A decent sized FANUC (let's say like an R2000iB-165F) can easily punch an EOAT THROUGH a person with no collision detect enabled. 

If you still can't move a robot into a certain area/position you probably have a DCS zone interference.  DCS or "Dual Check Safety" is the "virtual limitations" box that the FANUC draws in space that it is told it can't operate outside of/inside of (you can set it up with "go" zones and/or "no-go" zones).  - It is important to remember that even the back end of the robot is considered during these calculations (like the back of the J2-J3 "elbow" of the robot) and also the EOAT that you have set up in the config menu.  To turn DCS off you will need a code and to reboot the robot.  If you have one of the newer pendants with the 4D graphics, you can go to the DCS menu and physically see a computer-simulation and see which DCS zone is being violated (it will be red).  If you can jog the robot incrementally out of that zone, you will be free to move as normal again. 

And to repeat what someone else already said, Col Det set at 100 is the default.  200 is ridiculously sensitive (sudden turns in the program can trip it), and zero will rip aluminum or people apart if it's a big enough robot and you're not careful.  If you're experiencing regular collision detect faults, you can adjust this, and I wouldn't increment this any more than 5 or 10, then try running the program.  If you still have problems and have to set it less than 80 (which was kind of my made-up limitation line) you should double check your payload and EOAT settings.  Your robot might think it's trying to handle 165 KG when it's only handling 20.  It will overcompensate the brake curve and brakes, and cause jerking and then collision detect errors.  Most FANUC's have an "automatic payload calculator" option, where the robot will do a dance and measure the feedback to the motors during those movements to calculate the EOAT's weight and center of mass automatically. 

***IT IS IMPORTANT TO NOTE THAT THE DEFAULT PAYLOAD SET BY FANUC IN THE FACTORY IS THAT ROBOT'S MAXIMUM PAYLOAD SETTING - An R2000iB/210F ROBOT WILL AUTOMATICALLY BE SET TO 210 KG PAYLOAD BY FANUC WHEN THEY SHIP IT***