Data processing: generic control systems or specific application – Specific application – apparatus or process – Robot control
Reexamination Certificate
1998-12-31
2002-03-19
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Robot control
C700S245000, C700S249000, C700S258000, C700S259000, C700S260000, C700S261000, C700S262000, C700S264000, C414S744300, C414S744500, C414S744600, C074S490030
Reexamination Certificate
active
06360144
ABSTRACT:
TECHNICAL FIELD
The present invention relates to robot arm mechanisms and, in particular, to a self-teaching robot arm positioning method that determines whether there exists misalignment of a specimen holder relative to a robot arm mechanism to prevent the robot arm from reaching toward an unintended location on the specimen holder.
BACKGROUND OF THE INVENTION
Currently available robot arm mechanisms include pivotally joined multiple links that are driven by a first motor and are mechanically coupled to effect straight line movement of an end effector or hand and are equipped with a second, independently operating motor to angularly displace the hand about a central axis. Certain robot arm mechanisms are equipped with telescoping mechanisms that move the hand also in a direction perpendicular to the plane of straight line movement and angular displacement of the hand. The hand is provided with a vacuum outlet that secures a specimen, such as a semiconductor wafer, computer hard disk, or compact disk, to the hand as it transports the specimen between processing stations.
U.S. Pat. No. 4,897,015 of Abbe et al. describes a rotary-to-linear motion robot arm that uses a first motor to control a multi-linkage robot arm to produce straight line radial motion from motor-driven rotary motion. An additional motor may be coupled to the robot arm for operation independent of that of the first motor to angularly move the multi-linkage robot arm without radial motion. Because they independently produce radial motion and angular motion, the first and second motors produce useful robot arm movement when either one of them is operating.
The robot arm of the Abbe et al. patent extends and retracts an end effector (or a hand) along a straight line path by means of a mechanism that pivotally couples in a fixed relationship a first arm (or forearm) and a second (or upper) arm so that they move in predetermined directions in response to rotation of the upper arm. To achieve angular displacement of the hand, a &thgr; drive motor rotates the entire robot arm structure. The Abbe et al. patent describes no capability of the robot arm to reach around corners or travel along any path other than a straight line or a circular segment defined by a fixed radius.
U.S. Pat. No. 5,007,784 of Genov et al. describes a robot arm with an end effector structure that has two oppositely extending-hands, each of which is capable of picking up and transporting a specimen. The end effector structure has a central portion that is centrally pivotally mounted about the distal end of a second link or forearm. The extent of pivotal movement about all pivot axes is purposefully limited to prevent damage to vacuum pressure flexible conduits resulting from kinking or twisting caused by over-rotation in a single direction.
The coupling mechanism of a first link or upper arm, the forearm, and the end effector structure of the robot arm of the Genov et al. patent is more complex than that of the robot arm of the Abbe et al. patent. Nevertheless, the robot arm structures of the Abbe et al. and Genov et al. patents operate similarly in that each of the end effector structures picks up and transports specimens by using one motor to extend and retract a hand and another, different motor to rotate the entire robot arm structure to allow the hand to extend and retract at different ones of a restricted number of angular positions.
Robot arms of the type described by the Abbe et al. and Genov et al. patents secure a specimen to the hand by-means of vacuum pressure delivered to the hand through fluid conduits extending through the upper arm, forearm, and hand and around all of the pivot axes. The Abbe et al. patent is silent about a vacuum pressure delivery system, and the Genov et al. patent describes the use of flexible fluid conduits. The presence of flexible fluid conduits limits robot arm travel path planning because unidirectional robot arm link rotation about the pivot axes “winds up” the conduits and eventually causes them to break. Thus, conduit breakage prevention requirements prohibit-continuous robot arm rotation about any of the pivot axes and necessitate rewind maneuvers and travel path “lockout” spaces as part of robot arm travel path planning. The consequences of such rewind maneuvers are more complex and limited travel path planning, reduced throughput resulting from rewind time, and reduced available work space because of the lockout spaces.
Moreover, subject to lockout space constraints, commercial embodiments of such robot arms have delivered specimens to and retrieve specimens from stations angularly positioned about paths defined only by radial distances from the axes of rotation of the robot arms.
Thus, the robot arm structures described by the Abbe et al. and Genov et al. patents are incapable of transporting specimens between processing stations positioned in compact, irregularly shaped working spaces. For example, neither of these robot arm structures is set up to remove specimen wafers from and place specimen wafers in wafer cassettes having their openings positioned side-by-side in a straight line arrangement of a tightly packed working space.
Wafer cassettes are usually positioned side by side on a support structure along a radial path measured from the central axis of or along a straight line distance from the robot arm mechanism. These wafer cassettes are often misaligned from their nominal cassette opening arrangements relative to the robot arm mechanism. Such misalignment could cause a robot arm mechanism to direct the hand or the wafer it carries to strike the cassette instead of extend into its opening to, respectively, remove or replace a wafer. Robot arm mechanism contact with the cassette resulting from alignment offset can, therefore, create contaminant particles.
SUMMARY OF THE INVENTION
An object of the invention is, therefore, to provide a multiple link robot arm system that has straight line motion, extended reach, corner reacharound, and continuous bidirectional rotation capabilities for transporting specimens to virtually any location in an available work space that is free of lockout spaces.
Another object of the invention is to provide such a system that increases specimen processing throughput in the absence of robot arm rewind time and radial positioning of processing station requirements.
A further object of this invention is to provide such a system that is capable of continuous rotation in either direction with no susceptibility to kinking, twisting, or breaking of conduits delivering vacuum pressure to the hand.
Still another object of the invention is to provide such a system that uses two motors capable of synchronous operation and a linkage coupling mechanism that permit a hand of an end effector structure to change its extension as the multiple link robot arm mechanism to which the hand is associated changes its angular position.
Yet another object of the invention is to provide a system component misalignment correction technique for either mechanical alignment of system it components or robot arm mechanism trajectory control to compensate for support structure alignment offset.
Each of two preferred embodiments of the present invention includes two end effectors or hands. A first embodiment comprises two multiple link robot arm mechanisms mounted on a torso link that is capable of 360 degree rotation about a central or “torso” axis. Each robot arm mechanism includes an end effector having a single hand. A second embodiment is a modification of the first embodiment in that the former has one of the robot arm mechanisms removed from the torso link and substitutes on the remaining robot arm mechanism an end effector with oppositely extending hands for the end effector having a single hand.
Each of the multiple link robot arm mechanisms of the first and second embodiments uses two motors capable of synchronized operation to permit movement of the robot arm hand along a curvilinear path as the extension of the hand changes. A first motor rotates a forearm about an elbow axis that exten
Bacchi Paul
Filipski Paul S.
McDieunel Marc
Newport Corporation
Stoel Rives LLP
LandOfFree
Self-teaching robot arm position method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Self-teaching robot arm position method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Self-teaching robot arm position method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2832931