Grip Quality
Based on the actual product and gripper dimensions, payload weight, and the number of boxes being picked, Pally will estimate a reference value called ‘grip quality,’ which is used by the optimizer to choose between possible gripper rotations and reduce the number of boxes to be picked in one robot cycle. It will also reduce acceleration while handling products.
Understanding Grip quality
Grip quality in Pally is a numerical value that tells about the probability of losing boxes during transport. Usually, a higher grip quality implies a more reliable box transport between the pick and drop position. In comparison, a lower grip quality often means the gripper won’t be able to hold the box.
Grip quality is not an absolute measure and has no unit. But it can be used by the optimizer to compare different picks.
Grip quality estimation has a significant impact on the following program behaviour.
Can the robot pick more or fewer boxes in one cycle?
Which gripper rotation is best for the current pick?
Which combination of the vacuum zones is best for the next pick?
Can the robot move the box(es) with maximum speed and acceleration?
Settings related to Grip quality
It is possible to define a lower limit for the acceptable grip quality value. When the estimated grip quality drops below the minimum threshold, the program can decide to pick fewer boxes, use another gripper rotation at pickup, or even reduce the maximum allowed acceleration to guarantee box transport stability between the pick and drop position.
Smart acceleration
Adjusting the Smart Acceleration slider in Program / Pally / Movement / Speed will control the acceleration limitation by changing the minimum acceptable grip quality value.
Read more about smart acceleration here.
Note: It is also possible to change the value via the rf_min_grip_quality variable. This allows you to set the Minimum required grip quality for moving with full acceleration. The default value is 1.6.
Grip quality output in the logs
Make sure Pally log level is set to Info and start palletizing. Observe the log output during each pick and place. Grip quality related log messages will appear, and you can get an overview over the actual values.