Metal working – Method of mechanical manufacture – With testing or indicating
Reexamination Certificate
1995-06-05
2001-11-13
Bryant, David P. (Department: 3726)
Metal working
Method of mechanical manufacture
With testing or indicating
C029S407100, C382S291000
Reexamination Certificate
active
06314631
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. Robot Calibration, Ser. No. 06/453,910, now abandoned.
2. Electro-Optical Systems for Control of Robots, Manipulator Arms and Coordinate Measuring Machines, or “Robots and Manipulator Arms”, Ser. No. 592,443, filed Mar. 22, 1984, now U.S. Pat. No. 4,602,163.
3. Robot Tractors Ser. No. 06/323,395, now U.S. Pat. No. 4,482,960.
4. Robot Tractors, Vehicles and Machinery, Ser. No. 651,325, filed Sep. 17, 1984, now U.S. Pat. No. 4,769,700.
5. Electro-optical sensor systems for thread and hole inspection Ser. No. 06/064,867, now U.S. Pat. No. 4,315,688.
6. Method and apparatus electro-optically determining the dimension, attitude and location of objects: Ser. No. 06/034,278.
7. Method and apparatus for determining physical characteristics of object and object surfaces: Ser. No. 06/015,792, now U.S. Pat. No. 4,373,804.
8. New photodetector array based optical measurement systems: Ser. No. 06/163,290, now U.S. Pat. No. 4,394,683.
9. Electro-optical inspection, Ser. No. 06/073,226, now abandoned.
10. Co-ordinate measuring method and device, Ser. No. 06/201,081, now abandoned.
11. Electro-optical sensors with fiber optic bundles, Ser. No. 06/173,370, now U.S. Pat. No. 4,441,817.
12. Electro-optical surface roughness measurement and control Ser. No. 06/240,459, now abandoned.
13. Apparatus for determining dimensions, Ser. No. 06/134,465, now U.S. Pat. No. 4,403,860.
14. High speed electrooptical inspection, Ser. No. 06/203,866, now abandoned.
15. Fiber optic based robot controls, Ser. No. 06/200,401, now U.S. Pat. No. 4,460,826.
16. Electro-optical sensors for machine tool and robotic inspection, Ser. No. 06/247,399, now abandoned.
17. Electro-optical systems for control of robots, manipulator arms and coordinate measurement machines Ser. No. 06/262,497, now U.S. Pat. No. 4,453,085.
18. Method and apparatus for determining wear or breakage of tools and other defects, Ser. No. 06/323,397, now U.S. Pat. No. 4,420,253.
19. Electro-optical systems for detection of leakage and blockage, Ser. No. 06/323,399, now abandoned.
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 unobtrusive.
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 programmfunctions 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, assembling, inspecting, or working the object is then effected.
This invention further relates to methods and apparatus for determining the position of an object and guiding robots or other automation to handle or work on said object.
There are many instances in which it is desired to know the position of an object. In the manufacturing field, such instances include the position of objects along mass production lines, particularly those which are highly automated. For example, in a mass production line, it is frequently necessary to know with considerable precision the position of an object suspended from a conveyor system. This is particularly true in automated systems involving the use of robots for it is fundamentally necessary that the object be in a known position, relative to the robot, before the robot can execute a desired manipulation of the object.
In some instances, mechanical means are used to position the object and/or to orient the object in proper position for automated manipulation. For many applications, however, it is necessary to provide “vision” in order to determine the position of an object. This is particularly true in the case of robots which can perform a myriad of physical manipulations, all automatically. It is well recognized in the field of robots that robotic “vision” is one of the major obstacles to much wider use of robots which are presently quite sophisticated in terms of the manipulations of which they are capable.
Specifically the problem in plants of operationally using robots to handle or work on random parts on continuous conveyors is an enormous one. Since such conveyors are omni present in plants of all types, this problem must be effectively dealt with, if large scale robot usage is to become a reality.
In doing so, there are many types of ele
Bryant David P.
Great Lakes Intellectual Property
Larson & Taylor PLC
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