Laser aligned robotic machining system for use in rebuilding heavy machinery

• US 5,768,137 A
• Filed: 04/12/1995
• Issued: 06/16/1998
• Est. Priority Date: 04/12/1995
• Status: Expired due to Fees

• Current Assignee: American Research Corporation Of Virginia, Eastern Repair Fabrication
• Original Assignee: American Research Corporation Of Virginia, Eastern Repair Fabrication
• Inventors: Polidoro, Roger J., Thomas, Bruce L., Loftus, Lloyd K., Bass, Henry M., Churchill, Russell J.
• Primary Examiner(s): Elmore, Reba I.
• Assistant Examiner(s): Rao, Sheela S.
• Application Number:
  US08/421,008
• Time in Patent Office: 1,161 Days
• Field of Search: 364/474.28, 364/474.01, 364/474.02, 364/474.17, 364/474.34, 364/474.16, 364/474.09, 364/474.19, 356/139.03, 356/138, 356/152.1, 356/139.1, 356/141.4, 356/400, 82/117, 82/118, 228/102, 409/178, 409/174, 409/179, 409/185, 409/193, 409/204, 409/207, 382/108, 382/152
• US Class Current: 700/186
• CPC Class Codes: G05B 19/182 characterised by the machine tool function, e.g. thread cutting, cam making, tool direction control G05B19/21 - G05B19/40 take precedence
• CPC Class Codes: G05B 2219/33002 Artificial intelligence AI, expert, knowledge, rule based system KBS
• CPC Class Codes: G05B 2219/33027 Artificial neural network controller
• CPC Class Codes: G05B 2219/34065 Fuzzy logic, controller
• CPC Class Codes: G05B 2219/37275 Laser, interferometer
• CPC Class Codes: G05B 2219/50168 Retrofitting
• CPC Class Codes: G05B 2219/50173 Machine tool hang and move on rail above workpiece

Abstract

A precision positioning system is used for resurfacing and repairing rails and guideways of large, heavy machinery at users facilities. The system has new components, an entire machining system, a new alignment system, parallel platforms for tool support and surface scanning. A sectioned, portable monorail frame is held by fixed supports at the locus of a heavy machine requiring guideway straightening. Fixed guides extend along the outer surface of the monorail. Guide wheels and drive wheels contact the guides and support and move an outer tubular beam carriage. An assembly of machining tools is adjustably positioned on the carriage. Laser alignment sources and sensors are connected to the carriage and to heavy machines off-axis and parallel to the monorail. Intelligent controls precisely position the tools for resurfacing the rails and guideways. Scanning and a printout of machine guideway accuracy, before and after the operation, provide written verification of quality improvement. The system increases accuracy and speed of machining, reduces chatter and vibration, eliminates imprecise manual determinations, and returns the equipment to acceptable improved tolerances. The system has applications in any machine tool rebuilder or company with a machine tool in need of requalification. Applications also include rail transport, autonomous vehicles, micro-machining, inspection camera positioning, laser machining, material deposition and other operations such as drilling, heat treating, brazing and welding.

Claims

1. A precision positioning system for machinery comprising a monorail frame, multiple guides extending along an outer surface of the monorail frame, supports for holding the monorail frame in position, a movable base surrounding the monorail frame, multiple linear bearings positioned in the base for moving the base along the monorail frame, a machine tool head connected to the movable base, a tool platform positioned on the machine tool head, a tool mounted on the platform, a laser alignment system mounted to the movable base for positioning the tool, a parallel platform system connected to the movable base and to the tool for adjusting tool movement, an imaging system for mapping the guideway, and an intelligent controller for monitoring system behavior, for predicting and detecting chatter and for regulating frame deflections and platform positioning.

2. The system of claim 1, wherein the monorail frame is tubular and has a circular cross-section.

3. The apparatus of claim 1, further comprising multiple monorail frames connected together by integrated cam-type locking mechanisms for creating a lateral tool path parallel to the guideway.

4. The apparatus of claim 1, further comprising a motor connected to the tool for supplying power, and wherein the tool and the motor are adjustably and removably mounted on the tool platform.

5. The apparatus of claim 1, wherein the imaging system further comprises imaging sensors positioned in the tool platform.

6. The apparatus of claim 5, wherein the sensors are selected from the group consisting of a laser array, a mechanical probe array, and eddy current sensing.

7. The apparatus of claim 5, further comprising a movable arm connected to the tool platform and wherein the imaging sensors are positioned on the movable arm.

8. The apparatus of claim 7, wherein the movable arm is a retractable arm.

9. The apparatus of claim 1, wherein the laser alignment system is an arrangement of light sources and detectors for providing information in five axes of motion.

10. The apparatus of claim 9, wherein the light sources are selected from the group consisting of miniature lasers and laser diodes.

11. The apparatus of claim 9, wherein the detectors are selected from the group consisting of CCD arrays, photodetector arrays and quadrants.

12. The apparatus of claim 9, wherein the detectors are mounted to the machine tool head and the light sources are positioned at ends of a machinery bed.

13. The apparatus of claim 12, wherein the detectors are mounted and the light sources positioned for allowing beams emitted from the light sources and received by the detectors to be parallel or nearly parallel to the workpiece and off axis.

14. The apparatus of claim 13, wherein the light sources are adjustably mounted to allow rotation about a tool spin axis and a horizontal twist axis.

15. The apparatus of claim 13, further comprising a separate sensor for determining position in the translational direction.

16. The apparatus of claim 9, further comprising accelerometers connected to the movable base of the tool for course control.

17. The apparatus of claim 9, wherein the detectors are positioned at ends of a machine bed and the light sources are mounted on the machine tool head.

18. The apparatus of claim 1, wherein the laser alignment system has a laser position detector selected from the group consisting of quadrant sensing arrays, pixel arrays, interferometry and digital position sensitive detection.

19. The apparatus of claim 1, wherein the parallel platform system comprises variable geometry trusses that extend from a left side and a right side of the machine tool head to the moveable base, the trusses reacting to feedback from the laser alignment system.

20. The apparatus of claim 1, wherein the moveable base is a sled.

21. The apparatus of claim 1, wherein the intelligent controller is a fuzzy logic controller having a fuzzification interface for processing input from the imaging system and the laser alignment system, a knowledge base and decision making logic, and a defuzzification interface.

22. A method for resurfacing heavy machinery guideways comprising the steps of assembling multiple monorail frame sections near a workpiece, making an initial traversal of the workpiece to align a machine tool with light sources, detectors and workpiece, traversing the workpiece a second time for scanning and imaging a surface of the workpiece, machining the surface of the workpiece, and traversing the workpiece a final time for imaging the surface of the workpiece to verify accuracy of the machining and for creating a hard copy of an image scan.

23. The method of heavy machinery in situ guideway rebuilding comprising defining geometry of a machine, defining optimal tool orientation, defining monorail set up, establishing datum on or near the ends of a heavy machine bed, refining measurements, assembling a monorail, assembling a carriage on the monorail, assembling a tool platform on the carriage, finding coordinate transforms from the datum to the origin of the tool platform, establishing home limit position at an extreme limit of the carriage, the tool platform and a tool, setting up laser reference beams, aligning laser beams in X and Y axes and in roll, yaw and pitch, establishing laser beams as new datums, testing functionality of drives on the carriage and the platform, testing system operation and set up by traversing the machine bed, checking alignment and straightness of the monorail using the laser reference beams, mapping monorail deflections, creating a side view profile from extreme edges, selecting guideway faces to be scanned, orienting probes and initializing their positions as a base line reference,.scanning guideway faces along a Z axis, taking data at regular intervals, and displaying and recording scanned guideway faces.

24. The method of claim 23, further comprising verifying correct tool selection and set up, accounting for obstacles in machining workspace, graphically defining machining of the guideway faces, specifying machining parameters, and machining the guideway faces.

25. A precision positioning system comprising a monorail frame, multiple guides extending along an outer surface of the monorail frame, supports for holding the monorail frame in position, a movable base surrounding the monorail frame, multiple linear bearings positioned in the base for moving the base along the monorail frame, a parallel platform system connected to the movable base, a laser alignment system mounted to the movable base, an imaging system for mapping the guideway, and an intelligent controller for monitoring system behavior, for predicting and detecting chatter and for regulating frame deflections and platform positioning.

26. A parallel platform system for achieving motion in six axes comprising a moveable platform, a left base, a right base, and six independent actuators, wherein three actuators are fixed to the left base and three actuators are fixed to the right base.

27. A laser alignment system for sensing orientation in five axes comprising three x-y position detectors and three beams, the detectors and beams resolving orientation in x, y, roll, pitch and yaw directions.

28. A precision positioning system for automatically resurfacing heavy machinery comprising a monorail frame, multiple guides extending along an outer surface of the monorail frame, supports for holding the monorail frame in position, a movable base surrounding the monorail frame, multiple linear bearings positioned in the base for moving the base along the monorail frame, a machine tool head connected to the movable base, a tool platform positioned on the machine tool head for mounting a machine tool, a machine tool mounted on the platform for grinding, cutting or milling a heavy machinery guideway, a motor connected to the tool for supplying power, a laser alignment system mounted to the movable base for positioning the machine tool, a parallel platform system connected to the movable base and to the machine tool for adjusting tool movement, an imaging system for mapping the guideway, and an intelligent controller for monitoring system behavior, for predicting and detecting chatter and for regulating frame deflections and platform positioning.