Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
1998-11-30
2001-06-12
Ellis, Christopher P. (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C700S216000, C700S222000, C700S190000, C700S191000, C901S039000, C901S040000
Reexamination Certificate
active
06246924
ABSTRACT:
TECHNICAL FIELD
The present invention relates to end effectors of an automated equipment used in manufacturing lines, and more particularly to a method and apparatus for automatically realigning the end effector of the automated equipment after undesired contact of the end effector, to prevent a crash of the end effector.
BACKGROUND OF THE INVENTION
The present invention will be described for a gripper, within an automated handler which palletizes and/or depalletizes parts within a manufacturing line, as an example end effector of an automated equipment used in a manufacturing line. However, as would be apparent to one of ordinary skill in the art from the description herein, the present invention may be used for any other type of automated end effectors such as cutting or grinding tools, welding guns, or other type of automated pneumatic or servo-driven parts within any type of automated equipment that requires proper alignment of the end effector.
Referring to
FIG. 1
, an automated handler
100
is used in a manufacturing line for assembling an article of manufacture. The automated handler
100
includes a gripper
106
which is an example of an automated end effector within an automated equipment used in a manufacturing line. The automated handler
100
includes a base
102
, a movable arm
104
, and the gripper
106
. The position of the gripper
106
of the automated handler
100
is adjusted via the movable arm
104
such that the gripper
106
may reach down and grip a part
108
for picking up the part
108
to be incorporated in the article of manufacture.
A pallet
110
holds a plurality of parts
108
,
112
, and
114
. Referring to
FIG. 2
, a top view of the pallet
110
shows a plurality of cells
202
,
204
,
206
,
208
,
210
,
212
,
214
,
216
, and
218
. Typically, each of the plurality of cells holds a corresponding one of a plurality of parts. The pallet
110
is used to transfer the plurality of parts through the manufacturing line during a manufacturing process. For example, the plurality of parts may be automotive parts within an assembly line during manufacture of automotive systems.
The gripper
106
may reach down and grip a part from the pallet
110
for picking up the part to be incorporated in the article of manufacture. Alternatively, the gripper
106
may reach down to place a part into the pallet
110
to transfer parts from a manufacturing line into the pallet
110
.
In either case, referring to
FIG. 3
, the automated handler
100
may not be properly aligned with the cells of the pallet
110
. For example, some manufacturing processes heat the plurality of parts within the pallet
110
to high temperatures such as 500° C. In addition, the pallet
110
is reused for heating and cooling of a large number of parts. With such repeated heating and cooling of the pallet
110
, the pallet
110
warps in shape with time such that the gripper
106
is no longer properly aligned with the cells of the pallet
110
.
In any case, when the gripper
106
is not properly aligned with the cells of the pallet
110
, the gripper
106
collides with a part within the pallet
110
or any other part of the pallet
100
to result in an undesirable crash. In the prior art automated handler system, the crash of the gripper
106
into a part is detected. Upon detection of the crash in the prior art, the mechanism for holding the gripper from the automated handler
100
is loosened to minimize the stress of force applied on the part and on the gripper from the crash. For example, an air chamber of the prior art holding the gripper
106
is depressurized upon detection of a crash to minimize the stress of force applied on the part and on the gripper from the crash. In addition, an operator is then notified of the crash.
Unfortunately, the automated handler
100
of the prior art is manually reset after a crash. The position of the gripper
106
is manually readjusted to be properly aligned with respect to the position of a part within the pallet
110
to be picked up. The components on the automated handler
100
of the prior art are also manually reset to begin operation of the automated handler
100
again after a crash. However, such manual resetting of the automated handler
100
after a crash results in a relatively long down-time and high labor costs during the manufacturing process.
Thus, a mechanism for preventing an undesired crash of an end effector such as the automated handler
100
is desired
SUMMARY OF THE INVENTION
Accordingly, the present invention is an apparatus and method for automatically realigning an end effector of an automated equipment after an undesired contact of the end effector to prevent a crash of the end effector.
Generally, the present invention includes a plurality of contact detectors, and each of the contact detectors are disposed at a respective location with respect to the end effector. In addition, each of the contact detectors generates a respective signal for indicating direction of force on the end effector that results from the undesired contact. Furthermore, the present invention includes an end effector controller that is coupled to the plurality of contact detectors and to the end effector. The end effector controller causes the end effector to move to a reset position after the undesired contact when any of the respective signals from the plurality of contact detectors is greater than a first predetermined level. The reset position includes a respective positional off-set that corresponds to the direction of the force on the end effector that results from the undesired contact as indicated by which of the respective signals from the plurality of contact detectors is greater than the first predetermined level.
In another aspect of the present invention, the end effector controller ignores the respective signals from the plurality of contact detectors when each of the respective signals from the plurality of contact detectors is less than the first predetermined level. Thus, the present invention allows for some light contact by the end effector within a compliancy range. Alternatively, the end effector controller shuts down any driving mechanism of the end effector and notifies an operator of the undesired contact when any of the respective signals from the plurality of contact detectors is greater than a second predetermined level that is typically significantly higher than the first predetermined level. Thus, the present invention prevents damage to the end effector and any part with which the end effector has made contact in the case of a more drastic undesired contact with higher force.
In a further aspect of the present invention, the present invention further includes a carrier for holding the end effector. The carrier allows movement of the end effector along the direction of the force on the end effector that results from the undesired contact. In that case, each of the plurality of contact detectors generates a respective signal indicating the direction of the force on the end effector from the direction of the movement of the end effector during the undesired contact.
The present invention may be used to particular advantage when the carrier includes a hinge joint between the end effector and the carrier for allowing rotational movement of the gripper along the direction of the force on the end effector that results from the undesired contact. In that case, the plurality of contact detectors may also include a plurality of pneumatic cylinders with each pneumatic cylinder being disposed on a respective location on the carrier to retract when a respective direction of the force is applied on the end effector as a result of the undesired contact.
Alternatively, the present invention may be used to particular advantage when the carrier includes a compressed air spring disposed on the end effector for movement of the end effector along the direction of the force on the end effector that results from the undesired contact by deformation of the compressed air spring. In that case, a location of deformation of the co
Butler Michael E.
Choi Monica H.
Ellis Christopher P.
Honda of America Mfg. Inc.
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