Payload/Collision Guard

    I am currently dry running a new robot setup at 100% and I have a few concerns as I'm getting Disturbance Excess alarms. I know I do not have accurate payload info, I have worked with the design guys and we even have calculators from our corporate office that is supposed to take the Solidworks model and output payload info, but the numbers never seem accurate or are obviously way off. I have a few questions:

    1. I have ran Fanuc's built in auto-detect payload program and it never matches the payload values given to me by the design guys. Does anyone use the auto-detect and if so, does it match known good values?
    2. Does anyone know of any easier ways to calculate the payload, the formulas in Fanuc's manual are a little hard to follow.
    3. Are you using multiple payloads, i.e. payload#1 for carrying raw parts and then switch to payload#2 when carrying finished parts and so on? In my experience I have seen few programs like this, so I usually just set 1 payload while gripping raw and finished parts(worst case scenario) and I figured that was good, or is this some of my problem? I always figured it was better for the robot to expect more weight than actual, than to be surprised by extra weight?
    4. Is there a general consensus on when to adjust the collision guard and how high to do you adjust, or is this always done by "feel"? I basically default to 100% and then when im going to pick or drop parts, anywhere Im anticipating a collision, I go up to 125-150%. Is that not ideal?
    5. Normally I initially program a cell with no move at more than 50% of max possible speed and then ramp as needed by customer. In this cell the cycle time is quite critical so I have a lot of moves at 100% which im sure is making the robot more susceptible to errors due to my incorrect payload. Do most people start low and increase as I normally do or just leave the speed at 100% from the start unless there is an issue then slow down where needed?
    Thanks in advance for any help.

    1. I have used auto payload and it worked fine. I see what you mean though the values don't look right!
    2. No! I have had to weigh the tooling and guess on where the center of gravity if I don't have payload info.
    3. I use multiple pay loads when possible. It makes Collision Guard work better.
    4. I increase the sensitivity when picking and placing parts because that is when I am most concerned about crashes and damaging equipment. I run at 100% sensitivity when moving outside of critical areas. Or when the robot is moving in between flip and non flip configurations.
    5. Most of my robots run at 100%. I slow them down when running heavy parts.

    I have a couple of routers that occasionally get the Disturbance Excess alarms. It is not repeatable, so I'm never sure when/if it will occur. It doesn't fault the machine, so I generally just live with it. A higher collision threshold will probably save some false trips, but means a harder hit if a collision DOES occur. Some of our machines have a shock sensor that is set finer than the robot, but sometimes they cause more problems than they solve.

    Quote from Racermike123


    4. I increase the sensitivity when picking and placing parts because that is when I am most concerned about crashes and damaging equipment. I run at 100% sensitivity when moving outside of critical areas. Or when the robot is moving in between flip and non flip configurations.

    How high of an increase do you go-150% or even higher? I don't have that much formal training, but looking at past jobs by our company or even setups by other companies I cant recall ever seeing anyone use over 150% before. Is there a reason to not just go straight to 200% in a critical area?

    Quote from Iowan


    I have a couple of routers that occasionally get the Disturbance Excess alarms. It is not repeatable, so I'm never sure when/if it will occur. It doesn't fault the machine, so I generally just live with it. A higher collision threshold will probably save some false trips, but means a harder hit if a collision DOES occur. Some of our machines have a shock sensor that is set finer than the robot, but sometimes they cause more problems than they solve.

    I really do not want to deliver a brand new robot with Disturbance Excess alarms, if I can help it. The alarms aren't 100% repeatable as you mentioned, but I am narrowing them down to when and where they somethimes happen and adjusting the collision guard until they don't show up again in that area. A lot of trial and error so far.

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