Seek

Description

The seek function uses a sensor to determine the correct position to grab or drop an item. This function allows for working on stacks of items of varying thickness, and determining the exact positions of the items are either unknown or too hard to program.

The sensor can be a push button switch, a pressure sensor or a capacitive sensor.

Seek

To program a seek operation, define the following:

A - the starting point.
B to C - the stack direction. This means growing the stack when Stacking and shrinking the stack when Destacking.
D - the thickness of the items in the stack.

You must also define the condition for when the next stack position is reached, and a special program sequence that is performed at each stack position.

Speed and accelerations need to be given for the movement involved in the stack operation.

Stacking

During Stacking, the robot arm moves to point A, then moves opposite the direction to search for the next stack position. When the next stack position is found, the robot remembers it and performs the special sequence.

In subsequent rounds, the robot starts the search from the remembered position, incremented by the item's thickness along the direction.

Stacking is complete when the stack height is more than some defined number, or when a sensor gives a signal.

Destacking

During Destacking, the robot arm moves from point A in the given direction to search for the next item. The condition on the screen determines when the next item is reached. When the condition is satisfied, the robot remembers the position and performs the special sequence.

In subsequent rounds, the robot starts the search from the remembered position, incremented by the item's thickness along the direction.

Starting position

The starting position is where the stack operation starts. If the starting position is omitted, the stack starts at the robot arm’s current position.

Direction

The direction, given by positions B to C, is calculated as the position difference from the TCP of B to the TCP of C.

Direction does not consider the orientations of the points.

Command	Action
Next Stacking Position Expression	The robot arm moves along the direction vector while continuously evaluating whether the next stack position has been reached. When the expression is evaluated to `True` the special sequence is executed.
BeforeStart	The optional `BeforeStart` sequence is run just before the operation starts. This can be used to wait for ready signals.
AfterEnd	The optional `AfterEnd` sequence is run when the operation is finished. This can be used to signal conveyor motion to start, preparing for the next stack.
Pick/Place Sequence	The Pick/Place Sequence is a special program sequence performed at each stack position, similar to the Pallet operation.