Multitasking - Linking robot speed to extruder screw speed

stefpender

Hello, 

I need assistance figuring out how to run this task in the background while another task is running.  I know how to read actual robot velocity, I need help figuring out how to read programmed speeddata in order to compare actual velocity against programmed velocity

The basic idea is linking the extruder command to the difference between the actual and commanded robot velocity. This is done so that when the XY motion of the robot motion is accelerating or decelerating, the extruder will also be accelerating instead of running at a constant RPM. This helps significantly on corners.

A quick example: the XY motion is commanded for 10in/s, but is currently at just 5in/s – so currently at 50% of the commanded value. This 50% needs to be mirrored to the extruder. So if the extruder is commanded for 200RPM, it should be set to 100RPM. This calculation and adjustment needs to happen on the PLC in real time.

Any help would be greatly appreciated.

pseudo code attached.  

lemster68

When it comes down to it, all that really matters is the actual velocity.  What if the speed override on the pendant is set to 25%?  You can program the robot to go 2000 mm/s but if there is large reorientation, short distance, it will be nowhere near programmed speed.  In dispensing, you set up a reference speed.  This speed should not be exceeded while in the dispensing process.  That represents 100% sealer/glue flow rate needed.  The difference between that and lower speed scales down the required material flow rate.

stefpender

Does that approach compensate fore deacceleration/acceleration of the robot during stop/starts, corners, etc.?

lemster68

It does.  Sometimes it is necessary to increase the event preset time.

stefpender

Thanks lemster86 - do you know where I can find more information on configuring even preset time? I don't think I'm familiar with adjusting that?

lemster68

It is in the system parameter manual.  I think that you should find it in the Motion type, motion planner.