Patent ID: 8321051

Claim:
A workpiece pickup apparatus comprising: a gripping unit that sucks a workpiece so as to lift up the workpiece and releasably attach the workpiece to the gripping unit; a raising and lowering unit that lowers the gripping unit from a waiting position towards the workpiece and that raises the gripping unit and workpiece; a detecting unit that detects a current flowing to the raising and lowering unit, said current corresponding to a force with which the gripping unit is pressed against the workpiece by the raising and lowering unit; a comparison unit that compares the detected current with a reference current and provides a comparison result; and a controller that controls a movement of the gripping unit in the direction toward the workpiece based on the comparison result, wherein the controller lowers the gripping unit until the detected current reaches the reference current, and the controller stops the raising and lower unit from further lowering the gripping unit when the detected current reaches the reference current; and the detecting unit begins to detect the current after the gripping unit is lowered a given distance from a position in which the gripping unit contacts the workpiece.