Metal working – Method of mechanical manufacture – With testing or indicating
Reexamination Certificate
1992-04-29
2001-11-20
Bryant, David P. (Department: 3726)
Metal working
Method of mechanical manufacture
With testing or indicating
C029S407010, C029S701000, C029S720000, C029S721000, C700S114000
Reexamination Certificate
active
06317953
ABSTRACT:
BACKGROUND OF THE INVENTION
The following are co-pending applications in the same field showing the state of the art which are herein incorporated by reference:
1. Method and Apparatus for Automatically Handling, Assembly or Working on Objects, or “Targets”, U.S. Ser. No. 06/348,803, filed Feb. 16, 1982, now abandoned.
2. Robot Calibration, U.S. Ser. No. 06/453,910, filed Dec. 28, 1982, now abandoned.
3. Electro-Optical Systems for Control of Robots, Manipulator Arms and Coordinate Measuring Machines, or “Robots and Manipulator Arms”, U.S. Ser. No. 06/592,443, filed Mar. 22, 1984, now U.S. Pat. No. 4,602,163.
4. Robot Tractors U.S. Ser. No. 06/323,395, now U.S. Pat. No. 4,482,960.
5. Robot Tractors, Vehicles and Machinery, U.S. Ser. No. 06/651,325, filed Sep. 12, 1984, now U.S. Pat. No. 4,769,400.
These applications and the present invention are all commonly owned.
Flexible robot assembly is often very difficult in the absence of machine vision sensors to guide the operation. Even with such sensors, operation must be both accurate, ultra reliable, and fast enough to be justifiable relative to human labor. These criteria are seldom met by present day vision systems employing arbitrary gray level images and the like.
The target based invention described in reference
1
above has wide application to the assembly process. Described therein are several embodiments illustrating target based techniques which can overcome the limitations of present systems. The key to the use of the disclosed systems is that the target points on the part are easily discernable and unambiguous, after processing using rapid devices and other high speed analysis software.
The target system functions well because it is based on high contrast images and mathematical equations. To use targets one must know the part feature data base relative to the target points on the part. Targets on tooling, pallets and fixed members may also be of use. Special retro reflective targets give best contrast, but targets can be holes, corners or other easily determined natural part features.
Finally, where special targets are used which would not normally be present, techniques are disclosed to make these unobstrusive.
SUMMARY OF THE INVENTION
In accordance with the present invention, a method for controlling an assembly process is provided in which at least one first robot holds a first part in relation to a second part. Targets are provided on at least one of the robots or the first or second part. A TV camera then determines the position of the targets. From this determination, the assembly process is controlled.
In a preferred embodiment, the part held by the robot has a face on which the targets are located such that the TV camera can view these targets. In this manner, the robot is guided to handle or assemble the part.
A method for fabrication or assembly in which a fixture is provided is also disclosed. The location of a part having targets is determined with a TV camera and a robot then places the part on the fixture depending upon this determined location. A further object may be located on the fixture.
During a dynamic fabrication, it is also possible with the present invention to target the part so that corrections can be made during processing. Preferably, the targets are located in a finished assembly in such a manner as to be out of view. These targets can be covered up by a second object assembled with respect to the first object if applicable.
The present invention also includes a method for guiding objects into openings or onto protrusions. A plurality of target features are initially provided adjacent an opening or protrusion. These target features are imaged with a TV camera in order to determine the location of the target features. From this determined target location, an object is guided onto the opening or protrusion.
The present invention also makes use of a CAD system in a method of fabrication. Initially, the design of a finished assembly of parts is provided in a CAD system. The CAD system is also provided with individual part designs which are used to make up the assembly. These designs include special targets or natural features which serve as targets. The entire system is then provided with a logical progression of functions feeding program/functions to one or more robotic automation devices for assembly. Assembly is assisted by the use of TV cameras which are provided with the design data. The parts are then suitably assembled using images of the targets determined by the camera. Initially, the CAD system can be used to simulate the fabrication process.
In another preferred embodiment of the present invention, targets are provided on an object before a forming operation is performed. The location of the targets after forming are then determined. From this determined location, the attitude, shape, or dimension of the object or portions thereof are also determined. Depending upon the determined data, the handling, assemblying, inspecting, or working the object is then effected.
Other features and advantages of the present invention are stated or apparent from a detailed description of presently preferred embodiments of the invention found hereinbelow.
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IBM Technical Disclosure Bulletin, vol. 27 No. 6, Nov. 1984, pp. 3653-3655, M.S. Chester, M.A. Lavin, R.H. Taylor, “Chip-Placement Alignment Technique”, copy available in class 29 subclass 833.*
Decade of Robots 1983, pp 30-33, Yoon Yong, Maurice Bonner, “Simulation: Preventing Some Nasty Snarl-ups”, copy class 901, sublclass 6.*
Merritt, “Industrial Robots: Getting Smarter All the Time”, Instruments & Control Systems, Jul. 1982, pp. 32-38.*
Hollingum, “Robots That See, Feel and Sense”, The Engineer, Nov. 1980, p. 45, 48.*
Ruoff, “PACS—An Advanced Multitasking, Robot System”, The Industrial Robot, Jun. 1980, pp. 87-98.
Bryant David P.
Larson & Taylor PLC
LMI-Diffracto
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