User Frame Lab

When working with a robot, it is often desirable to align the Cartesian axes with your intended work area. This may be at a different position or angle than the base of the robot (World Frame) so the option of User Frames is used.

A User Frame is a redefined coordinate system allowing the operator to change where the intersection of the axes is (origin) as well as the direction of each.  

X, Y, and Z remain at right angles to one another but their positive directions from the newly defined origin are chosen.

This can be done through direct entry of measurements taken from the base of the robot but FANUC includes useful utilities for automatically calculating a new user frame. We will detail the 3-point method in this lab, which uses three points in space to determine position and orientation:

Origin

X Direction

Y Direction

Frames:

Frame Type	Details
Tool	Where the center of the effective point on the tool is, relative to the tool plate.
User	Where the work area’s origin (zero) point is located, as well as the direction of each cartesian axis.

Example:

As an example, a robot may have a conveyor bringing products into its work envelope. This conveyor may be at an arbitrary position relative to the robot, at an angle, or at a unique height in reference to the world frame. Teaching a user frame allows you to jog the robot in a way that is perfectly aligned with that conveyor, as well as teach points on the conveyor that are in reference to permanent marks on the conveyor's chassis. This allows those taught points to still be useful and accurate, even if the conveyor's position, height, and orientation is changed - just by redefining where the new position and orientation are.

Additionally, there may be multiple work areas – such as where the robot picks up objects and where it drops them off. By defining different user frames for different work areas, programs you write can be “universal” in that no matter what the configuration of the cell may change to (or even what robot is being used) the points you taught won’t have to be taught again.