The present invention relates to optical systems and methods for measuring and evaluating an interior surface of a cavity, and more particularly to scanning and evaluating a drilled hole in a structure.
Many industries, and in particular the aerospace industry and more particularly the commercial aircraft manufacturing industry, require the drilling of millions of precisely located holes to precise specifications. In many instances these holes are drilled by robotic systems that include drilling end effectors. After a group of holes has been drilled, the drilled holes are inspected to ensure that they are within tolerance. The inspection involves checking the diameter and circularity of each hole at different depths to ensure that each hole is straight and not elliptical, conical, hourglass-shaped, etc. Such inspections are performed by human quality assurance inspectors, who inspect, in an extremely laborious process, large groups of holes at one time. A quality insurance inspector may also be able to identify a damaged drill bit by, for example, identifying a large number of out-of-tolerance holes. Unfortunately, however, by the time the inspector identifies the damaged drill bit hundreds or even thousands of holes may have been drilled with that drill bit and may be out of tolerance. While an out of tolerance hole may perhaps be corrected by re-drilling the hole at a higher bore size, there are limits to the number of times a hole can be re-drilled.
Prior art attempts to evaluate drill holes include focal microscopy for fringe pattern analysis, i.e., image analysis. The pattern is compared with a pre-image of a correctly drilled hole. Such methods, however, are difficult to deploy and not particularly accurate. One known hole measurement apparatus is a capacitive probe. Such probes, however, take measurements in only one direction at a time, requiring multiple measurements to assess a hole. In addition, these capacitive probes are incapable of assembling a complete image of the inside of a drilled hole. Further, a capacitive probe must fit tightly into a drilled hole, be aligned closely to the center axis of the hole, and, for calibration purposes, must have the same probe-to-hole-side separation at all times (because its capacitance is calibrated according to the thickness of the layer of air between the probe and the wall of the hole). When such a capacitive probe identifies an out-of-tolerance hole, and the hole is re-drilled to a larger diameter, the capacitive probe must be replaced with a larger diameter probe to allow for re-measurement of the re-drilled hole.
The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification of this patent, all drawings and each claim.
The presently described systems and methods for measuring one or more drilled holes provide a systematic means to evaluate the configuration of each hole with speed and precision not currently available in the art. Thus, an optical system as provided herein measures one or more drilled holes in a structure, the one or more drilled holes each having a drilled hole wall. The optical system includes a probe having a probe body movable along a probe path extending into the drilled hole. The probe body houses an illumination source that directs illumination (which may be visible or invisible light) along an illumination path such that the illumination is emitted radially outwardly from the probe body. The illumination emitted from the probe will illuminate the drilled hole wall when the probe body is disposed at a location along the probe path.
Some of the illumination will be reflected from the drilled hole wall towards an optical sensor housed in the probe. Such reflected illumination is referred to herein as an “optical section signal” because, when received by the optical sensor and processed, it will be indicative of a two-dimensional cross-sectional shape of the drilled hole transverse to the probe body. The optical path from the drilled hole wall to the optical sensor is referred to herein as the optical section signal path of the probe.
A plurality of optical section signals reflected from a plurality of points along the probe path may be received by the optical sensor and processed to determine attributes of the drilled hole. By way of example, a drilled hole may include a countersunk shape and its attributes may be indicative of the countersunk shape. The attributes of the drilled hole can be used in a variety of methods, including methods to determine whether the hole is out of tolerance and/or should be re-drilled, to determine whether the drill that drilled the hole is damaged, and to predict whether the hole is and/or other holes are likely to go out of tolerance in the future.
The system optionally includes a robot to improve speed and repeatability of analyzing the one or more drilled holes. A robot included with the optical system movably supports the probe and provides signals indicative of the location of the probe along the probe path. The robot may comprise a probe deployment system such that the probe is moved from one drilled hole to another and to locations along the probe path.
The system can further comprise at least one processor that executes program code for processing data signals output by the optical sensor to determine attributes of the drilled hole. The processor may be communicatively coupled to the optical sensor and the robot for receiving data signals from the optical sensor and signals representing the associated locations of the probe from the robot. The processor may further be communicatively coupled to a memory storage device for storing attributes of drilled holes.
The optical sensor of the system is configured to generate two-dimensional hole section data when the probe is disposed at a location along the probe path and while the robot moves the probe continuously between first and second locations along the probe path. The optical sensor may comprise a detector, camera, and/or sensors based on CCD, CMOS or CID technology.
In certain embodiments, the optical probe may form a part of a hand-held system, wherein the hand-held system is configured to associate attributes of the drilled hole determined from optical section signals with hole identification data indicative of a hole location on the structure. A tripod, clamp, adaptor plate, suction cup, or guide may be coupled to the hand-held system to align the probe relative to the drilled hole.
The illumination source of the system may include at least one laser or light emitting diode. The probe body has a proximal end and a distal end and the distal end is extendable into the drilled hole. The illumination source may be coupled to or otherwise positioned in the distal end of the probe body, while the optical sensor is coupled to or otherwise positioned in the proximal end of the probe body. Alternatively, the illumination source and optical sensor may both be coupled to or otherwise positioned in the proximal or distal end of the probe body. The illumination source may be aligned with the probe body so as to direct illumination substantially parallel to a probe axis, or the illumination source may be aligned with the probe body so as to direct illumination substantially perpendicular or at an angle to a probe axis. The pattern of illumination emitted from the probe may be planar or conical. In one embodiment, the illumination path is defined in-part by an optical element, such as a reflective element or a lens.
The optical section signal path may similarly be defined in-part by an optical element, such as a lens or reflective element, configured to direct optical section signals toward the optical sensor. The optical section signal path is thus configured such that the optical sensor can image a cross section of the drilled hole associated with the location of the probe along the probe path. The illumination path and the optical section signal path may each be defined in-part by the same optical element. Alternatively, the illumination path may be defined in-part by a second optical element offset from the first optical element. At least one of the optical elements may include a conical surface. At least one of the optical elements may include a lens assembly including a plurality of lenses.
In some embodiments, at least one mask element may be arranged on or around the optical elements used to define the illumination path and/or optical section signal path so as to block unwanted reflections and thereby mitigate noise. Additionally or alternatively, the probe body may include an anti-reflective surface coating or anti-reflective surface configured to mitigate noise.
A method for using an optical scanning system for measuring a drilled hole in a structure having a drilled hole wall includes emitting illumination radially from a probe along an illumination path, where the probe is moveable along a probe path extending into the drilled hole. The emitted illumination illuminates the drilled hole wall and a portion of such illumination is reflected there from and directed to an optical sensor. The illumination detected by the optical sensor (i.e., the optical section signal) can be processed to determine a two-dimensional cross section of the drilled hole wall associated with a location of the probe along the probe path. Two-dimensional cross sections may be determined along the probe path so as to determine attributes of the drilled hole.
The method may further include moving the probe continuously between first and second locations along the probe path and providing signals indicative of the location of the probe along the probe path. The attributes of the drilled hole may further be associated with hole identification data indicative of a hole location on the structure. The illumination emitted by the illumination source maybe collimated or semi-collimated visible or invisible light.
Illustrative embodiments of the present invention are described in detail below with reference to the following drawing figures:
The subject matter of embodiments of the present invention is described herein with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.
An optical system for measuring drilled holes and methods of using the system provide precision and speed in the analysis of the integrity and specific configuration of the drilled holes.
In particular, the optical probe 101 includes an optical probe body which houses an illumination source. As shown by block 103, the illumination source is configured to emit illumination. As shown by block 105, the illumination emitted by the illumination source is directed along an illumination path that extends radially outwardly from the optical probe 101. The optical probe body may also house an arrangement of one or more physical components which define, at least in part, the illumination path. In particular, the illumination path begins at the illumination source and may be deflected, reflected and/or refracted by one or more intervening elements (e.g., mirrors, lenses, prisms, and/or optical fibers, etc.) toward the surface of the drilled hole wall. Thus, illumination travels from the illumination source along the optical illumination path and is emitted radially outwardly from the probe body so as to illuminate the surface of the drilled hole wall. As described below with respect to various embodiments, in three dimensional space the pattern of illumination emitted from the probe body will be planar when the illumination extends perpendicularly from the probe body, and it will be conical when the illumination extends at a non-perpendicular angle from the probe body. Still other illumination patterns may be provided in other embodiments. For example, with the illumination emitted from the probe body may be helical in shape, and the like.
Some of the illumination emitted from the probe body and reflected from the drilled hole wall will be directed toward an optical sensor, as shown by block 107. This reflected illumination is referred to herein an “optical section signal” because, when received by the optical sensor and subsequently processed, it can be used to determine a two-dimensional cross-sectional shape of the drilled hole wall transverse to the probe body. The optical path from the drilled hole wall to the optical sensor is referred to herein as the “optical section signal path”. Exemplary optical sensor embodiments are described in more detail below.
The optical sensor outputs data signals to a hole analysis module as shown in block 109. The hole analysis module may be executed by a local processor included in the optical probe 101 or by a remote computing device connected to the probe 101 via a wired or wireless network. The hole analysis module processes the sensor data signals to determine the two-dimensional cross-sectional shape of the drilled hole wall associated with the location of the probe. As the optical probe 101 moves along a probe path extending into the drilled hole, the hole analysis module receives additional sensor data signals and processes them to determine additional two-dimensional cross-sectional shapes of the drilled hole wall at different points along the probe path. The hole analysis module (or another program module) also receives probe information (e.g., the location of the probe relative to the probe path and the orientation of the probe relative the probe path) associated with the sensor signals representing each optical section signal, as shown by block 111. As discussed herein, the probe information may be obtained from robotic or optical probe deployment systems. At block 113, the hole analysis module utilizes these inputs from the optical sensor and associated locations of the probe information to determine attributes of the drilled hole. As shown by block 115, attributes of the drilled hole may be associated with hole identification data relating to the drilled hole itself (e.g., the location and/or identification number for the drilled hole on the structure).
Common attributes of the drilled hole that could be determined by the hole analysis module include hole diameter and circularity. One of skill in the art will recognize that not all drilled holes are the same and that the diameter to length ratio varies according to the purpose of the specific hole. The tolerance for variation also varies given the purpose of a drilled hole. However, the present systems provide a means to identify variations to determine whether the variations are within tolerance range. The system can determine other attributes including, but not limited to, bore diameter, surface finish, elongation, smoothness, depth, surface roughness, cracking, burr identification, pit identification, straightness, planarity, circularity, cylindricity, line profile (e.g., angular position of the hole axis with regard to the surface), surface profile (e.g., peak-to-valley surface profiles), perpendicularity (e.g., of the side walls to the bottom surface), angularity, parallelism (e.g., on opposite sides of the hole), symmetry, positional tolerance (e.g., tolerance in the location of the hole and alignment of the hole center point, center axis, or center of a plane), concentricity (i.e., commonality of an axis), circular runout (e.g., variation across the surface at one or more cross-sectional areas), total runout (e.g., variations across the entire surface of the hole), layer inspection, and countersink properties including taper angle, taper depth and counterbore properties. Additional attributes that may be determined for composite surfaces include, but are not limited to, microbuckling (e.g., a localized band of buckled composite fibers), waves, fish eyes (e.g., a defect with a center pore and radial fractures from the pore), delamination, gaps, cracks, lanes/suspensions, improper manufacturing techniques, disbond, and porosity.
The exemplary optical system 100 can also determine attributes external to a drilled hole, for example burrs or pits at or near a surface near the opening of the drilled hole. Furthermore, the system can be used to detect the position (e.g., the angle of an axis) of the hole with regard to the surface at the opening.
Optical probe systems described herein are suitable for identifying attributes of a wide range of drilled holes and to a high level of precision. Purely by way of example, optical probe embodiments described herein can profile and identify attributes of drilled holes having diameters of from about 3/16″ to ½″. The optical probe systems describe herein can measure diameter to within ±0.0003″ when standardized to a set ring which is certified to +/−0.00005″. Maximum and minimum diameter values are compared to upper and lower control limits. Countersink depths of drilled holes may range from about 0.080″ to 0.250″, have angles of about 82° to 100°, and be measured to an accuracy of ±0.0005″. Material stack thickness may vary from about 0.25″ to 2.00″ and may be measured to an accuracy of ±0.005″. The systems described herein can profile and determine attributes of holes drilled in composite, laminate and other mixed material surfaces, including those having any combination of carbon, aluminum, and titanium layers. It will be appreciated that the systems described herein would be suitable to profile and determine attributes of drilled holes having other dimensions and to other degrees of accuracy.
Various embodiments of an exemplary optical system 100, its operation, and methods of use are described with reference to
In this example, the robotic transport 262 is adapted to the optical probe 101 by mounting the optical probe 101 on an end effector 164 of the robotic transport 262. The optical probe 101 may be mounted in a fixed position on the end effector 264, with drilling apparatus 260 also mounted in a fixed position on the end effector 264 so that positioning the optical probe 101 at a drilled hole 280 after drilling requires repositioning of the robotic transport 262. Alternatively, both drilling apparatus 260 and the probe 101 may be rotatably mounted on the end effector 264 with separate home positions and the same deployed position, so that, after drilling, the drilling apparatus 260 is rotated to its home position and the optical probe 101 is rotated into its deployed position to measure a drilled hole 280. As a further alternative, the optical probe 101 may be the only operable device on the end effector 264, so that a drilling apparatus 260 is mounted on an entirely separate transport, and the optical probe 101 follows along and measures a drilled hole 280 after the drill has drilled the hole and moved to a next location to drill a next hole.
Because some materials have optical properties that do not lend themselves well to optical measurement, an opacifying material may be blown onto the drilled hole prior to measuring it and after the drilled hole has been cleaned. An example of an opacifier is talc or silicone powder. The material has the property of reflecting the ring of light in a predictable manner and it has a small and uniform particle size. After the hole is measured, the opacifying material may be removed (e.g., by vacuum) so that the hole is free of the material.
In the example of
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In addition, the drilled holes 280 in the example of
The apparatus of
Alternatively, or additionally, the hole analysis module 270 stores the three-dimensional profile data or other attributes for the drilled hole 280 (described above) in memory 268 for further use, optionally with data from other drilled holes 280 or with data for the same hole over time as a database. Thus, the profile and attribute data are useful in tracking changes to the drilled hole 280 over time, determining whether the drilled hole 280 is or may go out of tolerance in the future, and determining whether the drilling apparatus 260 used to drill the drilled hole 280 is damaged. Data collected over time in the database provides both historical comparisons as well as predictive value for the same or different drilled holes 280.
In the example of
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For example, the program modules may include an operating system 369. Aspects of the exemplary embodiments of the invention may be embodied in one or more hole analysis module(s) 270 (and/or other program modules) for controlling the operation of the light source 382 and the optical sensor 212 and for determining optical measurement of drilled holes 280 according to the various embodiments described herein. For example, the hole analysis program module(s) 270 may include programming logic for determining, from received reflections of projected rings 338, measurements 215 of a drilled hole 280. Measurements 215 of a drilled hole typically include drilled hole diameter, hole circularity, inferences whether a crack may be present in a hole wall, and numerous other attributes such as those described herein. Furthermore, designs 216, measurements 215 and other data accessed, used and stored by the hole analysis module(s) 270, as well as other data used by the optical probe 101, may be stored in the memory 268 or in/on any other computer-readable medium associated with the optical probe 106.
The processor 256 may be implemented as a Harvard architecture microcontroller with a control program in memory 268, a generally programmable Von Neumann architecture microprocessor with a control program in memory 268, field programmable gate array (‘FPGA’), complex programmable logic device (‘CPLD’), application-specific integrated circuit (‘ASIC’), a hard-wired network of asynchronous or synchronous logic, and otherwise.
The processor is coupled through a memory bus 257 to computer memory 268, which in this example is used to store measurements 215 of the drilled holes 280 as well as design 216 measurements for comparison with the actual measurements. The processor 156 of
The hole analysis module(s) 270 can also be programmed to infer from the measurements 215 whether, for example, a crack exists in the drilled hole 280 or whether a burr exists on the top and bottom surfaces of a drilled hole 280. The hole analysis module(s) 270 (e.g., in conjunction with the robot control module 271) can control the optical probe 101 to inspect the top and bottom surfaces of drilled holes 280 for burrs and the inside surface of drilled holes 280 for variations in surface finish that may indicate a crack. The hole analysis module(s) 270 in such embodiments is programmed to determine according to image processing algorithms the location of the light source 382 and optical probe 101 in the image of the received reflection of projected rings 138, and the light source 382 and optical probe 101 are configured for an expected surface finish for the material that is being inspected. If there is a significant deviation in surface finish indicating a crack or if there are burrs, at least one received reflection of a projected ring 138 of light will not appear as a radially symmetric ring in the image generated by the optical sensor 212, rather the image will have significant local variations in its appearance. That these variations are greater than a threshold is an indicator of a surface defect such as a burr or crack. Burrs can also be identified from white light images of the entrance and exit of the hole because the edge of the drilled hole 280 will not appear smooth and round. The bottom-facing surface of the drilled hole 280 can be imaged by an optical probe 101 configuration whereby a telecentric or low field of view lens images reflections off a cone mirror. In such embodiments, the imaging light 323 is configured so that reflections 336 of projected rings of light first reflect off of the mirror 344 and then back through the lens to the optical sensor 212 rather than first striking the lens itself.
The exemplary probe 101 of
To provide further explanation of orientation or calibration of an optical probe 101 within a drilled hole 280,
The unwanted reflections 440 result from the tilt of the probe with respect to the drilled hole 280, allowing at least some of the reflected light 437 to reflect through the optical probe 101 and effect a second reflection 446 off the opposite wall of the hole before arriving at the lens 214, thereby making the appearance of a first reflection that is actually a second reflection, in effect, producing noise that indicates a wrong placement of the optical probe 101 in the space of the drilled hole 280. The hole analysis module(s) 270 may detect the tilt by noting in its scan of optical data signals from the optical sensor 212 that, in addition to the received reflection of a project ring 338, the optical sensor 212 also bears illuminated pixels outside the ring, that is, illuminated pixels representing one or more unwanted reflections 440, e.g., unwanted reflection caused by the tilt of the optical probe's center axis 490 with respect to the center axis 488 of the drilled hole 280. The hole analysis module(s) 270 may alert the robot control module 271 of the unwanted reflections 140 and the robot control module 271 may then instruct the robotic transport 262 to tilt the optical probe 101 until the unwanted reflections 140 are minimized, thereby aligning the optical probe 101 within the drilled hole 280. The unwanted reflections 140 may not be completely eliminated, but minimizing them will sufficiently align the optical probe 101 to facilitate good quality measurement of the drilled hole 280.
To further explain orientation or calibration of an optical probe within a drilled hole,
In the example of
The hole analysis module 270 in this example therefore averages the intensity values as read from illuminated pixels in the received reflection of a project ring 338 of imaging light 323, calculates an average intensity value, and instructs the robotic transport 262 to position and reposition the optical probe 101 until all the pixels in the received reflection of the projected ring 338 have values within some predetermined variance from the average. The resulting positioning of the optical probe 101 typically will not be exactly on the center axis 488 of the drilled hole 280, but that is typically of little or no concern.
The optical probe 101 described above is but one example of a suitable optical probe for performing the methods described herein. Other optical probe embodiments are described.
The illumination source 382 may be at least one laser, light emitting diode or other light source as described above. The illumination source 382 in
As shown in
It will be appreciated that certain elements, such as the illumination source 382 or optical sensor 212, may not necessarily comprise part of the optical probe 600. Accordingly, the illumination source 382 may be external to the optical probe 600; the optical sensor 212 may be external to the optical probe 600, or both may be external to the optical probe 600.
One or more heat sinks 655 may optionally be coupled to the probe body 610 or illumination source 382. The heat sink 655 slows down heating of the optical probe 600 by transferring heat generated by the optical illumination source 382 away from the optical illumination source 382 and other components of the optical probe 600. The heat sink 655 may be a metal ring or other material that will conduct heat away from the optical illumination source 382.
The optical element 651 optionally includes a conical surface 652 to direct illumination from the illumination source 382 along the illumination path 620. In this illustration, the optical element 651 comprises a single conical mirror. When the optical probe 600 is moved distally (or proximally) into a drilled hole 280 along a probe axis 667 and the optical probe 600 is in operation, the illumination source 382 directs illumination along the illumination path 620 substantially parallel to the probe axis 667 and to the conical surface 652, where the illumination is directed radially outwardly from the probe body 610 so as to illuminate the inside surface 342 of the drilled hole 280.
The emitted illumination reflects from the inside surface 6342 of the drilled hole 280 to forms the optical section signal, which follows the optical section signal path 650, through the lens assembly 630, and onto a sensor surface 661 of the optical sensor 212. The lens assembly 630 includes a plurality of lenses 632 separated by a plurality of spacers 634. In addition to the components illustrated in the figures and described herein, various other numbers and configurations of lenses and spacers can be used. Furthermore, the light pattern of the illumination that is emitted from the optical probe body 610 in the embodiment of
As shown in
The exemplary embodiment illustrated in
A plurality of illumination sources 382 may be provided on or for the optical probe 600. As a result, additional light, or light from different angles, reaches the inside surface 342 of the drilled hole 280 so as to better allow for determination of certain attributes of the drilled hole 280, such as the presence and dimensions of a burr in the drilled hole 280.
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As explained above, the optical probe described herein can be used to identify attributes of a structure surface proximate a drilled hole.
An optical probe such as those described above may be incorporated into a robotic system as described herein or into a hand-held system.
The hand-held optical probe 1310 is inserted into the drilled hole 280 along an axis 1325 that is parallel to the axis of the drilled hole 280. While a robotic system may be able to readily achieve the proper alignment of the optical probe 1310, an operator manually using the hand-held optical probe 1310 to achieve the desired probe alignment would have more difficulty. Thus, the hand-held optical probe 1310 in combination with a mounting system can be affixed to the drilled structure 1330 to ensure proper alignment between the optical probe 1310 and a center axis 1325 of the drilled hole 280. Such a mounting system can include the tripod system 1340 such as that shown in
An example of a hand-held probe apparatus 1400 is shown, purely by way of illustration, in
By use of the display 1404, an operator moves the probe 1406 inside a drilled hole 280 by hand, tilts the probe to minimize unwanted reflections, positions the probe for uniformity of pixel intensity, and, when the probe is aligned as desired, presses a switch 1410 to instruct the hole analysis module 270 to capture the image presently illuminated on the sensor 212 and measure the drilled hole 280. In the apparatus 1400 of
The apparatus 1400 of
Alternatively, or additionally, the profile or data for various attributes for the drilled hole 280 may be stored in a local memory 268 or the memory of a remote computing device or memory storage device for further use, optionally with data from other holes, in various methods such as those described herein. Such methods include, but are not limited to, tracking changes to the drilled hole 280 over time, determining whether the drilled hole 280 or other holes is/are or may go out of tolerance in the future, and determining whether the drill used to drill the hole 280 is damaged.
Additional optical systems are described in the following patent applications, also assigned to the assignee of the present invention, which are incorporated herein by reference in their entirety for all purposes: U.S. patent application Ser. No. 13/417,767 filed Mar. 12, 2012 and published as US 2012/0281071 on Nov. 8, 2012; U.S. Provisional Patent Application No. 41/466,863 filed Mar. 23, 2011; U.S. patent application Ser. No. 13/417,649 filed Mar. 12, 2012; U.S. patent application Ser. No. 13/767,017, filed Feb. 14, 2013.
Robotics and Optical Probe Deployment Systems
The present invention additionally provides for robotics, such as optical probe deployment systems, to move the optical probe body continuously between first and second locations along a probe path extending into a drilled hole while the optical probe provides continuous, real-time scanning of the drilled hole. The robot additionally provides signals indicative of the location and/or orientation of the probe along the probe path associated with the optical signals transmitted from the optical probe. Advantageously, the present system is able to provide a complete image of the inside of the drilled hole for improved accuracy and verification of hole integrity and configuration (including for example, diameter and circularity), identification of out-of-tolerance holes, and inspection speed, as well as more accurate drill life estimates.
The hole scanning apparatus 1540 includes an optical probe 1550, optical probe deployment system 1560 and processor 1570. Under control of the processor 1570 (e.g., executing a robot control module 271), the optical probe deployment system 1560 moves the optical probe 1550 over a drilled hole 280 and then into the drilled hole 280. Once the optical probe 1550 is inside the drilled hole 280, the deployment system 1560 continuously moves the optical probe 1550 along an inside depth of the drilled hole 280. As the optical probe 1550 is continuously moved, the optical probe 1550 is continuously scanning the inside surface 342 of the drilled hole to provide a complete image of the diameter and circularity the drilled hole 280. It will be appreciated that the optical probe 1550 may comprise any of the embodiments described herein.
In addition to controlling the deployment system 1560, the processor 1570 (e.g., executing a hole analysis module 270) also processes optical probe data from an optical sensor 212 or detector of the optical probe 1550. The processing includes determining whether the drilled hole 280 is within a predetermined tolerance via comparison with design criteria 316. Optionally, the controller 1570 (e.g., executing a hole analysis module 270) may provide data to the robot or gantry 1530 indicating whether the drilled hole 280 is within tolerance or may directly provide the optical probe data to the robot or gantry.
Optionally, the optical probe deployment system 1560 may include a piezoelectric motor (not shown) for continuously moving the optical probe 1550 within the drilled hole 280. The optical probe deployment system 1560 may further include a miniature actuator (e.g., an air cylinder, linear motor, hydraulic cylinder) for moving the optical probe 1550 over a drilled hole 280.
The combination of the optical probe 1550 and the piezoelectric motor results in a hole scanning apparatus 1540 that is very small in size. The small size allows the hole scanning apparatus 1540 to be mounted to the end effector 1520 in a location that allows each hole to be measured immediately after drilling. Inspecting each hole after drilling is highly advantageous. It allows problems such as worn and chipped drill bits to be identified immediately, and prevents subsequent holes from being drilled with such drill bits.
The drilling apparatus 1525, hole scanning apparatus 1540, and cleaning apparatus 1545 may be rotatably mounted on the end effector 1520 or fixed on the end effector 1520. Alternatively, the end effector 1520 may allow for tools to be exchanged on the end effector and still further the hole scanning apparatus 1540 may be the only operable device on the end effector 1520 while drilling apparatus 1525 and cleaning apparatus 1545 may be mounted on entirely separate transports. The cleaning apparatus 1545 may include a compressed air nozzle, an industrial wire or non-wire brush, and/or a vacuum to clean the drilled hole and/or optical probe.
The optical probe 1650 is deployed by turning on a solenoid valve (not shown) to actuate an air cylinder 1820, causing the optical probe arm 1812 to swing and move the optical probe 1650 through an access door 1822 and into the pressure foot 1712. Shock absorbers 1824 reduce the abrupt shock of stopping the optical probe arm 1812 over a short distance. The shock absorbers 1824 also function as stops for accurately positioning the optical probe 1650. A second limit switch 1826 indicates an arm position where the optical probe 1650 is inside the pressure foot 1712.
Referring again to
The first circuit board 1910 also monitors limit switches 1818 and 1826 to assure the optical probe 1650 is in a known position. The first circuit board 1910 also controls the optical probe deployment system 1660 by generating signals that actuate the air cylinder solenoid, and also by supplying signals to a piezoelectric motor driver (not shown), which is on a second circuit board 1920. The piezoelectric motor driver generates the high frequency pulses that drive the piezoelectric linear motor 1828.
The control box 1740 has input and output ports for communicating with the robot or gantry 1630. The control box 1740 may have a data port (e.g., a serial port) for accepting user inputs as well as outputting diagnostics and other information. For instance, the control box 1740 can output hole scanning data for post processing.
The post processing may be used to perform drill life estimates. Typically, drills are automatically replaced according to a fixed schedule (e.g., after drilling a set number of holes). By monitoring the hole diameter and instead replacing drills at the end of their lives (e.g., when wear or damage is apparent), fewer drills are replaced. Consequently, time and money are saved.
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Methods for Measuring a Drilled Hole
As explained above, optical probes such as those described herein can be used to measure a drilled hole and generate three dimensional images thereof. Measurement includes determining attributes of the drilled hole as described herein.
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Methods for Identifying a Damaged Drill
Optical probes as described above may be used to identify a damaged drill. In aircraft manufacturing and other applications in which hundreds, thousands, or even more holes may be drilled in a single day, it is desirable to identify a damaged drill as soon as possible. Such damage may take the form of a chipped or bent drill bit or a mis-aligned drill (which could cause the drilled hole to not be perpendicular to the drilled surface). A damaged drill, if not quickly identified, could result in thousands of drilled holes being out of tolerance, necessitating re-drilling of the holes, or worse, replacement of the drilled structure.
An optical probe as described herein may be utilized in methods and systems for identifying a damaged drill.
The set of attributes is compared to a damaged drill profile (block 2130). Based on this comparison of attributes of the drilled hole to the damaged drill profile, a damaged drill can be identified (block 2140). For example, if a chipped bit is known to result in an inside surface of a drilled hole having an exceedingly rough surface, and similar attributes are identified in the drilled hole, then a damaged drill can be identified. Exemplary, but certainly not limiting, types of drill damage include a mis-aligned drill (block 2150) and physical damage to the drill tip (block 2160).
The first set of attributes of the first drilled hole are compared to the second set of attributes of the second drilled hole (block 2250). Damage of a drill (e.g., a mis-aligned drill (block 2270) or damaged drill tip (block 2280)) is identified based on the comparison between the first set of attributes and the second set of attributes (block 2260). The differences between the first set of attributes of the first drilled hole and the second set of attributes of the second drilled hole could also be compared to the damaged drill profile as is described above (block 2140). It will be appreciated that the methods described above and illustrated in
In certain embodiments, multiple sets of attributes of multiple drilled holes can be determined and compared to each other and/or to a damaged drill profile to identify a damaged drill. In this manner, changes in attributes from one drilled hole to another drilled hole (such as consecutive holes that were drilled using the same drill bit) could be used to identify exactly when the drill was damaged. An audio or visual alert could be provided if a damaged drill is identified. Optionally, the drilling operation could automatically be shut down upon detection of a damaged drill.
The identified attributes of the drilled hole can be used to determine whether the drilled hole needs to be re-drilled. Optionally, identification of the damaged drill can be used to determine if the drilled hole should be re-drilled. For example, it may be known from a damaged drill profile that a hole drilled with a drill that was mis-aligned by 3 degrees will necessarily need to be re-drilled.
Optionally, the method includes transmitting the set of attributes of the drilled hole to a storage database. Such attributes may include diameter, circularity, elongation, smoothness, roughness, tapering, depth or angularity. Other attributes of the drilled hole, such as but not limited to those listed above, may also be transmitted to a storage database. The set of attributes of the drilled hole may additionally be associated with hole identification data indicative of a hole location on the structure.
A system for identifying a damaged drill, including a damaged drill tip, may include a computer-readable memory storing a plurality of instructions for controlling a computer system (e.g., processor) to identify a damaged drill tip. The computer system may be configured for use with an optical probe for measuring a drilled hole in a structure, the drilled hole having a drilled hole wall, the optical probe having a probe body movable along a probe path extending into the drilled hole, and the probe body supporting an optical illumination path and an optical signal sensing path.
The plurality of instructions may include instructions that cause the computer system to determine a first set of attributes of a first drilled hole; instructions that cause the computer system to determine a second set of attributes of a second drilled hole; instructions that cause the computer system to compare the first set of attributes of the first drilled hole with the second set of attributes of the second drilled hole to detect one or more differences; instructions that cause the computer system to compare the one or more detected differences to a damaged tip profile; and instructions that cause the computer system to identify if a drill tip is damaged based on the comparison of the one or more detected differences to the damaged tip profile. Additionally or alternatively, the computer-readable memory may further store instructions that cause the computer system to provide an audio or visual alert if the damaged drill tip is identified or other instructions that cause the computer system to carry out any of the steps described above. A first set of multiple two dimensional cross-sectional signals for a hole are stored. Optionally, comparable data for a second set of multiple two dimensional cross-sectional signals for a same hole at a subsequent point in time or a different hole are then compared to the first set of multiple two dimensional cross-sectional signals. Optionally, one or more data points outside a preset tolerance limit for one or more attributes is identified. Such identification can be provided by the processor in the form of a signal to the user.
Methods of Profiling/Inspecting Drilled Holes
Optical probes according to embodiments described above may be used to profile drilled holes and/or inspect drilled holes. The entire “life” of a drilled hole, from its time of initial drilling to retirement of the structure including the drilled hole (e.g., retirement of the aircraft that includes the drilled hole) can be profiled. In addition, the drilled hole profile, or “fingerprint,” can be utilized by various entities for various purposes.
For example, with reference to
An optical probe according to the present invention may utilized in methods and systems for profiling a drilled hole.
A first set of attributes of the drilled hole is determined from the two-dimensional cross sectional image signals at a first time period (block 2320), and a second set of attributes of the drilled hole at a second time period is received (block 2330). The first set of attributes is compared with the second set of attributes to identify one or more changes that have occurred to the drilled hole between the first and second time periods (block 2340).
Based on the comparison (block 2340) of the same drilled hole over a period of time, it can be determined (or predicted) whether the identified one or more changes result in the drilled hole being out of tolerance or will lead to the drilled hole being out of tolerance in the future. The comparison can include determining one or more changes between the first set of attributes that were in tolerance and the second set of attributes that are not within tolerance.
Optionally, the identified one or more changes is compared to a database of other drilled hole profiles that have become out of tolerance over time. For example, if it is known from a database that a drilled hole having Attribute X at Time Y was found to be out of tolerance when that drilled hole was inspected at Time Z, and a drilled hole is identified as having Attribute X, then it can be determined from the comparison of the drilled hole to the database that the drilled hole may go out of tolerance some time before Time Z. A decision to re-drill the hole prior to Time Z may then be made.
The information acquired by the determinations described above can be used to update threshold values associated with design tolerance criteria for the drilled hole. For example, if it can be determined or predicted that a particular initial attribute of a drilled hole eventually resulted in the drilled hole being out of tolerance (when the second set of attributes was identified), then the threshold value for that attribute could be updated so that when similar attributes in other drilled holes are compared to the updated threshold value, it can be determined that the attribute should be eliminated from the drilled hole (e.g., by re-drilling the hole), thus preventing the drilled hole from going out of tolerance in the future.
Optionally, the first and second set of attributes of the drilled hole may be transmitted to a storage database. The storage database may be maintained by the aircraft manufacturer or the airline carrier or a third party. In one example, the aircraft manufacturer could perform the comparison of stored attributes and notify the aircraft operator that a drilled hole may go out of tolerance in the future.
Sets of attributes for a particular drilled hole may be associated with hole identification data indicative of the location of the hole on the structure (e.g., the aircraft). In this manner, a storage database can be maintained that includes sets of attributes for every hole on an aircraft, and comparisons of changes in attributes for one drilled hole may be compared to changes in attributes of other drilled holes to identify global trends in changes to attributes of drilled holes. In this manner, it may be possible to identify an area of a particular structure having a defect not specifically relating to a single drilled hole by comparing changes in attributes of multiple drilled holes in that area.
The first or second set of attributes may comprise diameter, circularity, elongation, smoothness, roughness, tapering, depth, angularity, or other attributes as described herein. Based on this comparison, hole defects such as burrs, cracks, pits, or other drilled hole defects or unacceptable configurations can be identified.
A system for implementing the method illustrated in
Based on the comparison, it can be determined if the drilled hole should be re-drilled based on the comparison. Optionally, the identified one or more changes of the drilled hole is transmitted to a storage database. The storage database can be data mined to determine which changes will result in other drilled holes being out of tolerance in the future. The set of threshold values can be updated based on the determination. In certain embodiments, the present and previous set of attributes of the drilled hole is associated with hole identification data indicative of a hole location on the structure as described above.
The method illustrated in
While embodiments of the optical probe and methods described herein are substantially described with reference to their applicability in the aircraft and airline industries, embodiments of the optical probe and methods described herein may be applied in other industries, such as but not limited to the nuclear power plant, wind energy and automotive industries. Nuclear power plant reactor pressure vessels, for example, have drilled holes which must be manufactured within extremely tight tolerances, and it would be particularly useful to identify and profile attributes of these drilled holes during construction of the pressure vessel and following subsequent operation of the reactor plant.
It should be understood that the various methods described herein for measuring, profiling and otherwise evaluating drilled holes using an optical probes may be implemented by way of computer-readable instructions or other program code, which may have various different and alternative functional arrangements, processing flows, method steps, etc. Any suitable programming, scripting, or other type of language or combinations of languages may be used to implement the teachings contained herein in software to be used in programming or configuring a computing device.
Unless specifically stated otherwise, discussions in this specification utilizing terms such as “processing,” “computing,” “calculating,” “determining,” and “identifying” or the like refer to actions or processes of a computing device. The use of “adapted to” or “configured to” herein is meant as open and inclusive language that does not foreclose devices adapted to or configured to perform additional tasks or steps. Additionally, the use of “based on” is meant to be open and inclusive, in that a process, step, calculation, or other action “based on” one or more recited conditions or values may, in practice, be based on additional conditions or values beyond those recited. Headings, lists, and numbering included herein are for ease of explanation only and are not meant to be limiting.
Numerous specific details are set forth herein to provide a thorough understanding of the subject matter of the various embodiments. However, those skilled in the art will understand that such subject matter may be practiced without some or all of these specific details. In other instances, methods, apparatuses, or systems that would be known by one of ordinary skill have not been described in detail so as not to obscure claimed subject matter.
Further, different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the claims below.
The present application is a continuation-in-part of U.S. patent application Ser. No. 13/767,017, filed Feb. 14, 2013, currently pending, the disclosure of which is incorporated by reference herein in its entirety for all purposes.
Number | Date | Country | |
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61871002 | Aug 2013 | US |
Number | Date | Country | |
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Parent | 13767017 | Feb 2013 | US |
Child | 14283533 | US |