Excessive segment

    Hi


    Welding robot DX200.

    In one of the jobs there is a tight corner the robot welds through. I noticed right away when writing the job in MotoSim that there's a lot of axis movement in that corner but there was no other way to go through it as I couldn't stop the weld in the corner and I didn't have any better angle to approach from.

    It workd in MotoSim with the given speed and most of the times it works on the robot as well, but sometimes I get an alarm going through the corner: Excessive Segment [R1:HIGH SLURBT] - R and T highlighted.

    Alarm Reset and restart will make the robot successfuly finish the weld.

    I'm using P-variable (value found with search) to shift this weld and it seems that certain P-variable values shift the corner to where the axis movement is still to great for the given speed . I've seen this before where a linear movement with shift could not be executed with a certain P-variable value, but worked great without it.

    I decreased the speed for the corner - I still get the alarm but not so often.

    Now my question - is there a parameter (or any other way) that could make the robot go through this corner with the maximum speed it can handle BUT not greater than defined by the MOVL instruction?

    Have you tried adding additional movement commands through the corner? That could help; I've had similar joint errors before for doing large rotational axis changes in one move that were corrected by doing 3 smaller fluid ones. Normally this is fixed with a switch from MOVL to MOVJ but I assume your weld is active so that's no good.

    I also use OLP to make a lot of my programs and they always end up needing changes like this once I load them onto the bot... It's frustrating. But that's just where simulation is right now, I guess.

    In addition to WhyDoesMyRobotHateMe's idea another possibility, slowing down (I know, cycle time) and changing your arc conditions could help.

    I know a thing or two, because I’ve seen a thing or two. Don't even ask about a third thing. I won't know it.

    In a 3h cycle, it doesn't really matter if I slow a 3cm weld down. I'd do it right away if I knew the speed at which it can go through the corner with all possible P-variable shift values.

    There is a third option as well - I can just use the P-variable value to shift not the robot, but the base axis (it's a gantry with 3-way base) - that would still shift the weld but would keep the robot movement constant.

    At the moment I'd like to know if there is a parameter (or other setting) that can avoid the Excessive Segment alarm by limiting the speed where needed.

    I usually can get past these alarms with slight changes in tool z-axis rotations for the start, corner and end positions that decrease the amount of travel for the affected axes, in this case R & T. Slight changes in torch angle and increasing the corner PL may also decrease the amount of joint rotation enough to consistently run without the alarm. I do this before lowering speeds.

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