Sets and gets the Boolean flag that indicates if the ZClearance distance is interpreted as being along the world or tool Z-axis of a Location Object.
location_object.ZWorld = <new_Boolean_value>
-or-
...location_object.ZWorld
Prerequisites
None
Parameters
None
Remarks
For most applications, it is not possible for the robot to move a part directly to its final destination. Normally, the destination must be approached from an intermediate position that allows the robot and part to avoid obstacles. Likewise, after picking up a part, it is typically required that the part be retracted a small distance to avoid dragging the part across the mating surface. To implement these motions to and from a final destination, GPL includes a Move.Approach method. Instead of moving to the “total position” of the location_object, this method moves the robot to a clearance position that is relative to the location_object.
To simplify the specification of the “approach” or “clearance” position, each location_object includes a ZClearance distance. This specifies the distance along a Z-axis for the approach position.
If the ZWorld property of the location_object is True, the clearance position is interpreted as being directly above (or below) the “total position” of the location_object in the world coordinate system at the Z value specified by ZClearance. For example, if the “total position” of the location_object is at an X, Y, Z value of (10,20,30) and ZClearance is 52.3 and ZWorld is True, the approach position would be (10,20,52.3).
A world Z clearance position is often used if the robot is loading or unloading a box and the robot must clear the edge of the box independent of how far into the box it must reach.
If the ZWorld property of the location_object is False, the clearance position is a relative distance along the negative Z-axis of the robot’s tool. This clearance distance corresponds to having the robot retract an incremental distance along the major axis of its tool or gripper. For example, if the “total position” of the location_object is at an X, Y, Z value of (10,20,30) and ZClearance is 52.3 and ZWorld is False and the robot’s tool is pointed along the positive world X-axis, the approach position would be (-42.3,20,30).
A tool Z clearance position is typically utilized if the robot is tending a number of machines and you always want to retract the gripper a fixed distance from each machine before moving to the next Location.
By making use of GPL’s robot kinematics option, Cartesian approach specifications can be automatically applied to both Cartesian and Angles location_objects.
Examples
Dim loc1 As New Location ' Create new Location set to defaults
loc1.XYZ(10,20,30,0,180,0) ' Define destination
loc1.ZWorld = True ' Normally defaults to False
loc1.ZClearance = 52.3
Move.Approach (loc1, prof1) ' Use global Profile, move to (10,20,52.3)
See Also
Location Class | location_object.ZClearance | Move.Approach