Patent ID: 11970344
Assignee: DENSO WAVE INCORPORATED
Field: Handling (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. An apparatus for controlling a robot arm with an end effector for packing one or more workpieces in a box-shaped open container, the apparatus comprising:
a position specifying unit configured to specify a position in the box-shaped open container at which a selected workpiece among the one or more workpieces is located, the box-shaped open container having a bottom wall and at least one side wall that extends to a top of the box-shaped open container, an inner surface of the at least one side wall being covered, from the top, with a contact prevention sheet having an indefinite and changeable shape, the contact prevention sheet preventing direct contact between the selected workpiece and the inner surface and being put on the top of the container without being completely fixed thereto such that the contact prevention sheet covers the top and the inner surface; and
an operation controlling unit configured to:
statistically calculate a predetermined safety distance based on a plurality of values of an inward projection of a side part of the contact prevention sheet that covers the top and the inner surface of the at least one side wall, the predetermined safety distance being for preventing the selected workpiece from interfering with the contact prevention sheet;
instruct the robot arm to pick up the selected workpiece with the end effector;
determine whether the position specified by the position specifying unit in the box-shaped open container is adjacent to the inner surface of the at least one side wall of the container; and
instruct the robot arm to move the selected workpiece picked up by the end effector of the robot arm downward while preventing the selected workpiece picked up by the end effector of the robot arm from entering a predetermined safety zone in response to a determination that the specified position in the box-shaped open container is adjacent to the inner surface of the at least one side wall of the container,

wherein the safety zone represents an internal space of the box-shaped open container defined between the inner surface of the at least one side wall and a virtual plane that is parallel to the at least one side wall and is separated away therefrom by the predetermined safety distance in a horizontal direction perpendicular to the at least one side wall and the virtual plane, and
wherein the operation controlling unit is further configured to, in response to the determination that the specified position in the box-shaped open container is adjacent to the inner surface of the at least one side wall of the container, instruct the robot arm to perform:
a first motion that moves the end effector to thereby locate an outer edge of the selected and picked-up workpiece, which is closest to the at least one side wall of the box-shaped open container, at an offset position, the offset position being offset by the safety distance relative to the at least one side wall of the box-shaped open container in the horizontal direction thereof;
a second motion that moves the end effector straight downward until the selected and picked-up workpiece reaches a predetermined height position in a height direction of the box-shaped open container; and
a third motion that moves the end effector toward the specified position into the box-shaped open container.