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WO1998053993A1 - Systeme et procede pour la gravure avec controle de trajectoire d'outil arbitraire - Google Patents

Systeme et procede pour la gravure avec controle de trajectoire d'outil arbitraire Download PDF

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Publication number
WO1998053993A1
WO1998053993A1 PCT/US1998/010674 US9810674W WO9853993A1 WO 1998053993 A1 WO1998053993 A1 WO 1998053993A1 US 9810674 W US9810674 W US 9810674W WO 9853993 A1 WO9853993 A1 WO 9853993A1
Authority
WO
WIPO (PCT)
Prior art keywords
image data
toolpath
control point
recited
engraving
Prior art date
Application number
PCT/US1998/010674
Other languages
English (en)
Inventor
Tony D. Beckett
Mark B. Burns
Neal D. Clements
Louis D. Duchesneau
John W. Fraser
Kenneth W. Jackson
Original Assignee
Ohio Electronic Engravers, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US08/865,733 external-priority patent/US6007230A/en
Application filed by Ohio Electronic Engravers, Inc. filed Critical Ohio Electronic Engravers, Inc.
Publication of WO1998053993A1 publication Critical patent/WO1998053993A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/02—Engraving; Heads therefor
    • B41C1/04—Engraving; Heads therefor using heads controlled by an electric information signal
    • B41C1/045—Mechanical engraving heads

Definitions

  • This invention relates to gravure engraving and, more particularly, to an engraving system and method for providing an improved engraved image by utilizing digital toolpath planning, digital tuning and closed loop feedback control .
  • the process of traditional electro-mechanical engraving consists of cutting small areas or cells of copper from a surface of a copper cylinder.
  • the cells are formed by superimposing a screening signal and an image signal.
  • the screening signal is an AC sinusoidal waveform and the image signal is added to it to cause a cutting tool or stylus to move or oscillate to engrave the cells.
  • U.S. Patent 5,245,260 discloses techniques for modifying a screening signal in order to control the placement of the cell.
  • Another problem with the approaches of the past is that the screening and layout of the cells were directly dependent upon the AC sinusoidal waveform, thereby eliminating the flexibility of the engraving quality because prior screening waveforms have consisted of constant AC sinusoids which were difficult to modify sensitive to the image to be engraved.
  • the traditional filtering techniques generally produced an engraving head frequency response which did not carry enough amplitude at higher frequencies, such as frequencies in excess of 5.5 KHz.
  • the techniques of the past did not permit a user to interactively and easily change the characteristics, such as filter coefficients, of the filters in order to manipulate or tune the engraving head as desired.
  • the filter characteristics were subject to electronic component errors and could not be moved from one circuit board to another with the required precision.
  • this invention comprises a method for controlling a path of a tool in an engraver comprising the steps of generating image data corresponding to an image to be engraved, generating control points in response to the image data, processing the control points to define a toolpath and driving the tool to engrave a workpiece in response to the toolpath.
  • this invention comprises a method for engraving a workpiece with a pattern of engraved areas on a workpiece comprising the steps of generating image data corresponding to an image to be engraved, deriving a toolpath directly from the image data, using the toolpath to determine an engraving signal and energizing an engraving head to engrave the workpiece using the engraving signal.
  • this invention comprises a toolpath controller for controlling a path of a tool on an engraving head in an engraver comprising an image data processor for generating control points in response to the image data, the image data processor further comprising a toolpath generator for processing the control points to define a toolpath and a signal generator coupled to the image data processor and to the engraving head for receiving the toolpath and for energizing the engraving head to drive the tool to engrave a workpiece in response to the toolpath.
  • this invention comprises an engraver for engraving a workpiece comprising an engraving bed, an engraving head situated on the engraving bed for engraving at least one engraved area on the workpiece, the engraving head comprising a tool, a processor coupled to the engraving head for receiving image data and also for generating an engraving signal for engraving at least one engraved area and a digital toolpath planner associated with the processor for planning a toolpath in response to the image data, the processor using the toolpath to generate the engraving signal .
  • this invention comprises a method for generating an engraving signal for controlling an engraving head such that a tool on the engraving head follows a desired toolpath, the method comprising the steps of generating an engraving signal and processing the engraving signal to provide an engraving head frequency response defining a substantially constant gain for frequencies less than a predetermined frequency.
  • this invention comprises an engraving head tuner for tuning an engraving head such that a tool on the engraving head follows a desired toolpath, the engraving head tuner comprising a processor for receiving an engraving signal and also for processing the engraving signal to provide an engraving head frequency response defining a substantially constant gain for frequencies less than a predetermined frequency.
  • this invention comprises an engraver for engraving at least one engraved area, the engraver comprising an engraving bed, an engraving head associated with the engraving bed, the engraving head comprising a tool and an engraving head tuner coupled to the engraving head for processing an engraving signal to provide an engraving head frequency response defining a substantially constant gain for frequencies less than a predetermined frequency.
  • this invention comprises a method for tuning an engraving head, comprising the steps of using at least one filter for filtering an engraving signal to eliminate undesirable resonance, establishing a filter coefficient for at least one filter, coupling a user interface to at least one filter, determining whether at least one parameter for at least one filter needs to be altered, using the user interface to programmably adjust at least one parameter if at least one parameter needs to be altered.
  • this invention comprises an engraver comprising an engraving bed, an engraving head associated with the engraving bed, the engraving head comprising a cutting tool and at least one filter associated with the engraving head, at least one filter comprising at least one parameter and at least one filter coefficient and an user interface coupled to at least one filter, the user interface enabling a user to programmably adjust at least one parameter to change a response characteristic of the filter.
  • this invention comprises a velocity sensor for sensing a position of a cutting tool for engraving a cylinder comprising an armature for holding the cutting tool, at least one electromagnetic driver comprising at least one drive coil therearound for oscillating the armature when at least one drive coil is energized and a sensor positioned in operative relationship with at least one electromagnetic driver for determining a cutting tool position in response thereto.
  • this invention comprises a method for stabilizing an engraving head comprising a motor for driving a cutting tool comprising the steps of energizing the motor with a first drive signal applied to a first coil, sensing a motor velocity using a second coil and stabilizing the engraving head using the motor velocity.
  • this invention comprises an engraver for engraving at least one engraved area, the engraver comprising an engraving bed, an engraving head associated with the engraving bed, the engraving head comprising an armature having a cutting tool secured thereto, an engraving head tuner coupled to the engraving head for processing an engraving signal to provide a processed signal comprising a frequency response defining a substantially constant gain for frequencies less than a predetermined frequency, at least one electromagnetic driver comprising at least one drive coil, at least one electromagnetic driver being positioned in operative relationship with the armature for oscillating the armature when at least one drive coil is energized with the processed signal and a sensor positioned in operative relationship with at least one electromagnetic driver for determining a velocity of the electromagnetic driver in response thereto, the engraving head tuner tuning the engraving head resonance in response to the velocity and the processed signal.
  • this invention comprises a method for scaling image data to be engraved, the method comprising the steps of generating image data corresponding to an image to be engraved, determining whether the image data is continuous tone data or line- work data, generating either continuous tone control points or a line-work control points if it is determined that the image data is continuous tone data or line-work data .
  • this invention comprises an engraver for engraving a workpiece comprising an engraving bed, an engraving head situated on the engraving bed for engraving at least one engraved area on the workpiece, the engraving head comprising a tool, a processor coupled to the engraving head for receiving image data and also for generating an engraving signal for engraving at least one engraved area and a digital toolpath planner associated with the processor for planning a toolpath in response to the image data, the processor using the toolpath to generate the engraving signal .
  • this invention comprises a method for controlling a path of a toll in an engraver, comprising the steps of generating image data corresponding to an image to be engraved; generating control points in response to the image data; processing the control points to define a toolpath; and driving the tool to engrave a workpiece in response to the toolpath.
  • image data comprises first image data and second image data
  • the method further comprising the steps of :
  • the image data comprises a plurality of image data sets
  • the method further comprising the steps of: • determining if a summed density for the plurality of image data sets comprises a majority of the density for all of the image data;
  • fitting step further comprises the step of :
  • a still further aspect of the invention is the provision of an engraver for engraving a workpiece consisting of an engraving bed; an engraving head situated on the engraving bed for engraving at least one engraved area on the workpiece, the engraving head comprising a tool; processor means coupled to the engraving head for receiving image data and also for generating an engraving signal for engraving the at least one engraved area; and digital toolpath planner means associated with the processor means for planning a toolpath in response to the image data, the processor means using the toolpath to generate the engraving signal .
  • Another object of the invention is to provide an engraver for engraving a workpiece with one or more of the following additional or optional features (either along or in combination) : • a toolpath data signal processor means for receiving digital image data associated with an image to be engraved and for generating the toolpath in response thereto. • a toolpath data signal processor means for receiving the image data associated with the image to be engraved and for generating a plurality of control points in response thereto.
  • a curve fitter means for receiving a plurality of control points and for fitting a curve thereto, the curve defining the toolpath.
  • a curve fitter means for receiving the plurality of control points and for fitting a curve thereto, the curve defining the toolpath.
  • control points generally correspond to an entry point wherein the tool begins engraving one of the at least one engraved area, an exit point wherein the tool exits the one of the at least one engraved area, and a third control point which lies between the entry point and the exit points.
  • the third point comprises a center point corresponding to a density center of the image data.
  • processor means processes the image data to provide a predetermined number of density values, the processor means further comprising:
  • an image density determiner means for receiving the predetermined number of density values and for determining a total percentage image density.
  • processor means further comprises :
  • density center determining means for receiving the predetermined number of density values and for using the predetermined number of density values to determine a density center.
  • processor means receives the image data and determines a total percentage image density therefor and uses the total percentage image density to establish a plurality of control points for defining the toolpath.
  • toolpath data signal processor establishes the entry control point and the exit control point at a surface of the workpiece upon the occurrence of a predetermined condition.
  • the predetermined condition comprises a density being less than a predetermined density.
  • the processor means further comprising:
  • a double frequency determiner means for determining if a summed image density for the first image data and the second image data comprises a majority of the density for all of the image data.
  • the double frequency determiner separating the first image data and the second image data into a first image data subset and a second image data subset if the image density exceeds a majority and generating control points for each of the first image data subset and the second image data subset .
  • the curve fitter further comprises a cubic spline interpolation routine for generating the tool curve .
  • Yet another object of the invention is the provision of a method for generating an engraving signal for controlling an engraving head such that a tool on the engraving head follows a desired toolpath, the method comprising the steps of generating an engraving signal; and processing the engraving signal to provide an engraving head frequency response defining a substantially constant gain for frequencies less than a predetermined frequency.
  • a method for generating an engraving signal for controlling an engraving head with one or more of the following additional or optional features (either alone or in combination) : • processing the engraving signal to provide a processed signal defining a substantially constant gain for frequencies less than 10 kHz.
  • the method further comprises the step of: • performing the processing step using at least one filter for counteracting the engraving head's natural resonances.
  • the method further comprises the step of: • performing the processing step using at least one filter for counteracting the engraving head's natural resonance.
  • the at least one filter comprises an infinite impulse response filter.
  • the emphasis filter comprises an infinite impulse response filter.
  • a still further object of the invention is the provision of an engraving head tuner for tuning an engraving head such that a tool on the engraving head follows a desired toolpath, the engraving head tuner comprising a processor for receiving an engraving signal and also for processing the engraving signal to provide an engraving head frequency response defining a substantially constant gain for frequencies less than a predetermined frequency.
  • the engraving head tuner comprising a processor for receiving an engraving signal and also for processing the engraving signal to provide an engraving head frequency response defining a substantially constant gain for frequencies less than a predetermined frequency.
  • the engraving head tuner processes the engraving signal to provide a processed signal comprising the frequency response defining a substantially constant gain for frequencies less than 10 kHz; • wherein the engraving head tuner comprises at least one filter for counteracting the engraving head's natural resonances .
  • the engraving head tuner further comprises at least one emphasis filter for boosting the engraving signal at frequencies in excess of an emphasis frequency but less than the predetermined frequency.
  • the engraving head tuner further comprises at least one filter for counteracting the engraving head's natural resonances.
  • the engraving head tuner further comprises at least one emphasis filter for boosting the engraving signal at frequencies in excess of an emphasis frequency but less than the predetermined frequency.
  • the at least one filter comprises an infinite impulse response filter.
  • the emphasis filter comprises an infinite impulse response filter.
  • the at least one filter and the emphasis filter each comprise an infinite impulse response filter.
  • control point generator for receiving image data corresponding to an image to be engraved and for generating control points in response thereto
  • an interpolator for receiving the control points and for generating the engraving signal in response thereto. • wherein the engraving head further comprises a velocity sensor for sensing a position of a cutting tool for engraving a cylinder.
  • the engraving head further comprises an armature for holding the cutting tool.
  • At least one electromagnetic driver comprising at least one drive coil therearound for oscillating the armature when the at least one drive coil is energized.
  • the velocity sensor further comprising:
  • Yet another object of the invention is to provide an engraver for engraving at least one engraved area, the engraver comprising an engraving bed, an engraving head associated with the engraving bed, the engraving head comprising a tool; and an engraving head tuner coupled to the engraving head for processing an engraving signal to provide an engraving head frequency response defining a substantially constant gain for frequencies less than a predetermined frequency.
  • the engraving head tuner processes the engraving signal to provide the engraving head frequency response defining a substantially constant gain for frequencies less than 10 kHz. • wherein the engraving head tuner comprises at least one filter for counteracting the engraving head' s natural resonances .
  • the engraving head tuner further comprises at least one emphasis filter for boosting the engraving signal at frequencies in excess of an emphasis frequency but less than the predetermined frequency.
  • the engraving head tuner further comprises at least one filter for counteracting the engraving head's natural resonances.
  • the engraving head tuner further comprises at least one emphasis filter for boosting the engraving signal at frequencies in excess of an emphasis frequency but less than the predetermined frequency.
  • the at least one filter comprises an infinite impulse response filter.
  • the emphasis filter comprises an infinite impulse response filter.
  • the at least one filter and the emphasis filter each comprise an infinite impulse response filter.
  • the engraving head tuner is coupled to a toolpath digital signal consisting of a control point generator for receiving image data corresponding to an image to be engraved and for generating control points in response thereto and an interpolator for receiving the control points and for generating the engraving signal in response thereto.
  • the at least one emphasis filter comprises at least one parameter for engraving head tuner further consists of a filter processor coupled to the at least one emphasis filter, the filter processor comprising a user interface for programming the at least one parameter associated with the at least emphasis one filter.
  • the at least one emphasis filter comprises at least one parameter for engraving head tuner further consists of a filter processor coupled to the at least one filter, the filter processor comprising a user interface for programming the at least one parameter associated with the at least one filter.
  • the engraving head further consists of a velocity sensor for sensing a position of a cutting tool for engraving a cylinder.
  • the engraving head further consists of an armature for holding the cutting tool, at least one electromagnetic driver comprising at least one drive coil therearound for oscillating the armature when the at least one drive coil is energized, the velocity sensor further consisting of a sensing coil positioned around the at least one electromagnetic driver and a sensing circuit coupled to the sensing coil for measuring a velocity of the armature and for converting the velocity into the cutting tool position.
  • Another object of the invention is to provide a method for tuning an engraving head, consisting of the steps of using at least one filter for filtering an engraving signal to eliminate undesirable resonance, establishing a filter coefficient for the at least one filter, coupling a user interface to the at least one filter, determining whether at least one parameter for the at least one filter needs to be altered, using the user interface to programmably adjust the at least one parameter if the at least one parameter needs to be altered.
  • the determining step further comprises the step of determining whether either a frequency or a notch depth needs to be altered.
  • the predetermined frequency is less than about 10 kHz.
  • the at least one filter comprises an infinite impulse response filter.
  • the automatically adjusting step further comprises the step of : • using a sensor for sensing a position of a cutting tool for engraving a cylinder.
  • a still further object of the invention is to provide an engraver comprising an engraving bed; an engraving head associated with the engraving bed, the engraving head comprising a cutting tool; and at least one filter associated with the engraving head, the at least one filter comprising at least one parameter and at least one filter coefficient; and an user interface coupled to the at least one filter, the user interface enabling a user to programmably adjust the at least one parameter to change a response characteristic of the filter.
  • the at least one parameter comprises a frequency and a notch depth.
  • the at least one parameter comprises a frequency. • wherein the at least one parameter comprises a notch depth.
  • the engraver further comprises a processor coupled between the user interface and the at least one filter, the processor comprising means for automatically adjusting the at least one parameter in response to an automatic tuning request.
  • the user interface comprises means for programmably adjusting the at least one parameter to cause the at least one filter to define a head response with substantially constant gain for frequencies less than a predetermined frequency.
  • the predetermined frequency is less than about 10 kHz.
  • the user interface comprises means for programmably adjusting at least one parameter of at least one emphasis filter associated with the engraving head to boost the engraving head' s response at frequencies in excess of an emphasis frequency.
  • the at least one filter comprises an infinite impulse response filter.
  • the means comprises an infinite impulse response filter coupled to an interactive user interface.
  • the means comprises an infinite impulse response filter coupled to an interactive user interface.
  • the engraving head further comprises a velocity sensor for sensing a position of a cutting tool for engraving a cylinder.
  • the engraving head further comprises an armature for holding the cutting tool, at least one electromagnetic driver comprising at least one drive coil therearound for oscillating the armature when the at least one drive coil is energized, the velocity sensor further comprising a sensing coil positioned around the at least one electromagnetic driver and a sensing circuit coupled to the sensing coil for measuring a velocity of the armature and for converting the velocity into the cutting tool position.
  • Another object of the invention is to provide a method for stabilizing an engraving head comprising a motor for driving a cutting tool comprising the steps of energizing the motor with a first drive signal applied to a first coil, sensing a motor velocity using a second coil, and stabilizing the engraving head using the motor velocity.
  • the second coil comprises less than five windings situated around the motor.
  • the method further comprises the step of sensing a cutting tool position for the cutting tool, using the sensed cutting tool position, the motor velocity and the first drive signal to perform the stabilization.
  • a still further object is to provide an engraver for engraving at least one engraved area, the engraver comprising an engraving bed, an engraving head associated with the engraving bed, the engraving head comprising an armature having a cutting tool secured thereto, an engraving head tuner coupled to the engraving head for processing an engraving signal to provide a processed signal comprising a frequency response defining a substantially constant gain for frequencies less than a predetermined frequency, at least one electromagnetic driver comprising at least one drive coil, the at least one electromagnetic driver being positioned in operative relationship with the armature for oscillating the armature when the at least one drive coil is energized with the processed signal, and a sensor positioned in operative relationship with the at least one electromagnetic driver for determining a velocity of the armature in response thereto, the engraving head tuner tuning the engraving head resonance in response to the velocity and the processed signal.
  • the sensor comprises a sensing coil positioned around the at least one electromagnetic driver.
  • a sensing circuit coupled to the sensing coil for measuring a velocity of the armature and for converting the velocity into the cutting tool position.
  • sensing coil measures a rate of change of flux through the at least one drive coil.
  • the sensing coil comprises not more than five windings about the electromagnetic driver.
  • the engraving head tuner processes the engraving signal to provide a processed signal comprising a frequency response defining a substantially constant gain for frequencies less than 10 kHz.
  • the engraving head tuner comprises at least one filter for counteracting the engraving head's natural resonances.
  • the engraving head tuner further comprises at least one emphasis filter for boosting the engraving signal at frequencies in excess of an emphasis frequency but less than the predetermined frequency. • wherein the engraving head tuner further comprises at least one filter for counteracting the engraving head's natural resonances.
  • the engraving head tuner further comprises at least one emphasis filter for boosting the engraving signal at frequencies in excess of an emphasis frequency but less than the predetermined frequency.
  • the at least one filter comprises an infinite impulse response filter.
  • the emphasis filter comprises an infinite impulse response filter.
  • the at least one filter and the emphasis filter each comprise an infinite impulse response filter.
  • the engraving head tuner is coupled to a toolpath digital signal processor comprising a control point generator for receiving image data corresponding to an image to be engraved and for generating control points in response thereto, and an interpolator for receiving the control points and for generating the engraving signal in response thereto.
  • Another object of the invention is to provide a method for scaling image data to be engraved, the method comprising the steps of generating image data corresponding to an image to be engraved, determining whether the image data is continuous tone data or line- work data, generating either continuous tone control points or a line-work control points if it is determined that the image data is continuous tone data or line-work data.
  • the method further comprises the steps of processing the control points to define a toolpath and energizing an engraving head to engrave a workpiece in response to the toolpath. • wherein the method further comprises the step of applying a either a continuous tone sealer or a line- work sealer to the image data if it is determined during the determining step that the image data is continuous tone or line-work, respectively, in order to generate the continuous tone control points or line-work control points .
  • a still further object of the invention is the provision of an engraver for engraving a workpiece comprising an engraving bed, an engraving head situated on the engraving bed for engraving at least one engraved area on the workpiece, the engraving head comprising a tool, a processor coupled to the engraving head for receiving image data and also for generating an engraving signal for engraving the at least one engraved area, and a digital toolpath planner associated with the processor for planning a toolpath in response to the image data, the processor using the toolpath to generate the engraving signal.
  • the processor further comprises a toolpath data signal processor for receiving digital image data associated with an image to be engraved and for generating the toolpath in response thereto.
  • the toolpath data signal processor comprises sealer means for generating image data corresponding to an image to be engraved, for determining whether the image data is continuous tone data or line- work data, and for generating either continuous tone control points or line-work control points if it is determined that the image data is continuous tone data or line-work data.
  • the toolpath data signal processor further comprises sealer means for processing the control points to define the toolpath and for energizing an engraving head to engrave a workpiece in response to the toolpath.
  • sealer means applies either a continuous tone sealer or a line-work sealer to the image data if it is determined during the determining step that the image data is continuous tone or line-work, respectively, in order to generate the continuous tone control points or line-work control points.
  • Fig. 1 is a perspective view of an engraving system comprising features of the present invention
  • Fig. 2 is a schematic diagram illustrating a processor in accordance with an embodiment of the invention.
  • Fig. 3 is an illustration of image data, control points generated using the image data, and a toolpath generated using the control points;
  • Fig. 4 is an illustration of image data, control points generated using the image data, and a toolpath generated from the control points;
  • Fig. 4A is an illustration of image data, control points generated using the image data, and a toolpath generated from the control points;
  • FIG. 5A and 5B taken together, illustrate a system and method or routine for generating control points, such as the control points shown in Fig. 3 ;
  • Fig. 6 is another schematic illustration of a synchronization routine in accordance with one embodiment of the invention;
  • Fig. 7 is a schematic view of a tuning process system and routine
  • Fig. 8 is a schematic view of an automatic tuning user interface routine in accordance with one embodiment of the invention
  • Fig. 9 is a graphical view of a typical prior art engraving head response
  • Fig. 10 is a graphical view of a prior art engraving head response after notch filtering
  • Fig. 11 is a graphical view of engraving head response characteristic after filtering in accordance with the present invention
  • Fig. 12 is a view of a user interface in accordance with one embodiment of the present invention
  • Fig. 13 is a sectional view of an engraving head motor, showing an armature, a velocity sensing coil associated with a pair of electromagnets;
  • Fig. 14 is a schematic illustration of a cutting tool velocity and position extraction circuit in accordance with one embodiment of the present invention;
  • Fig. 15 is overall schematic diagram of an operation of the system and routine of the present invention upon system power up;
  • Fig. 16 illustrates a kanjii character engraved using features of the present invention.
  • Fig. 17 illustrates a kanjii character engraved using prior art techniques.
  • Fig. 1 is a perspective view of a preferred embodiment of an engraver, designated generally as engraver 10.
  • the engraver 10 is a gravure engraver, but the invention may be suitable for use with other types of engravers.
  • the engraver 10 may have a surrounding slidable safety cabinet structure which is not shown for ease of illustration.
  • Engraver 10 comprises a base 12 having a headstock 14 and tailstock 16 which are slidably mounted in a track 18 such that the headstock 14 and tailstock 16 can move towards and away from each other.
  • engraver 10 comprises a plurality of linear actuators or first drive motor means or a first drive motor 20 and a second drive motor means or second drive motor 22 which are capable of driving the headstock 14 and tailstock 16, respectively, towards and away from each other.
  • the drive motors may cause the headstock 14 and tailstock 16 to be actuated to a fully retracted position or to a cylinder support position shown in Fig. 1.
  • the drive motors 20 and 22 may be selectively energized to cause headstock 14 and tailstock 16 to be actuated either independently or simultaneously.
  • a single drive motor may be used with a single lead screw (not shown) having reversed threads (not shown) on which either end causes the headstock 14 and tailstock 16 to move simultaneously towards and away from each other as the lead screw is driven.
  • Driving both the headstock 14 and tailstock 16 permits cylinders 24 of varying lengths to be loaded by an overhead crane, for example, whose path is perpendicular to the cylinder's 24 axis of rotation.
  • a stationary headstock 14 and tailstock 16 may be used with a driven tailstock 16 or headstock 14, respectively, if, for example, a cylinder loading mechanism (not shown) loads the cylinder 24 by moving it in a direction which is generally parallel to the axis of rotation of the engraver 10.
  • the cylinder 24 comprises a first end 24b and a second end 24c each having receiving openings (not shown) for receiving ends 16a and 14a, respectively.
  • the ends 14a and 16a are conically shaped and compliment the shape of the receiving openings in order to support the cylinder 24 at an engraving station 26 of the engraver 10.
  • the headstock 14 and tailstock 16 would each include a gripping device or chuck (not shown) to rotatably support the cylinder 20 at the engraving station 26.
  • the engraver 10 also comprises an engraving head 28 having a cutting tool or stylus 30 for engraving a surface 24a on the cylinder 24.
  • surface 24a preferably has a copper coating of the type used in gravure engraving.
  • the engraving head 28 is slidably mounted on a carriage 32 such that a third drive means or third drive motor 27 can drive the engraving head 28 towards and away from the cylinder 24 in a direction which is generally radial with respect to the center axis of cylinder 24.
  • the carriage 32 is also slidably mounted on base 12 such that it traverses the entire surface 24a of cylinder 24 in the direction of double arrow 36 in Fig. 1. Note that this direction is generally parallel to the axis of the cylinder 24.
  • the engraver 10 also comprises a lead screw (not shown) and drive motors (not shown) for causing the carriage 32 to move in the direction of double arrow 36.
  • a lead screw (not shown)
  • drive motors (not shown) for causing the carriage 32 to move in the direction of double arrow 36.
  • Various features of the following patents may be used in the engraving system and method of the present invention is similar to that shown in U.S. Patent No's. 5,424,845, 5,424,846, 5,438,422, 5,440,398, 5,454,306, 5,492,057 and 5,329,215 all of which are assigned to the same assignee as the present invention and which are incorporated herein by reference and made a part hereof.
  • the engraver 10 also comprises a drive means or a drive motor 11 while rotatably driving the support shaft 14a in order to rotatably drive the cylinder 24 when energized by an engraver controller 38.
  • the engraver 10 comprises the engraver controller 38 which generally controls the operation of the engraver 10 and which also controls all the drive motors, such as drive motors 11, 20, 22 and 27.
  • the drive motors 11, 20, 22 and 27 are selectively responsive to the engraver controller 38.
  • the engraver 10 further comprises an image processing means or image processing computer 40 coupled to controller 38 for generating digital image data associated with an image to be processed and/or engraved by engraver 10.
  • image processing computer 40 is the image processing work station model no. IPW- 2000 available from Ohio Electronic Engravers, Inc. of Dayton, Ohio who is the assignee of the present invention.
  • a feature of the present invention is that it provides means for generating a toolpath to be followed by stylus 30 in order to engrave a series of engraved areas in response to a stream of digital image data.
  • the engraver 10 comprises at least one digital signal processor or processing means (shown schematically as block 42 in Fig.
  • controller 38 for processing any image data or signal received from controller 38, filtering, and adjusting the signal received in response to various feedback information in the manner described later herein.
  • the processing means 42 is also coupled to an amplifier 53 for amplifying any signal generated by processing means for transmission to engraving head 28 in order to energize engraving head 28 to move stylus 30 to engrave a pattern of engraved areas on cylinder surface 24a.
  • the digital signal processor 42 comprises toolpath means or a toolpath controller 44 for generating an engraving toolpath to be followed by stylus 30 in order to effect engraving.
  • processor 42 is capable of generating a plurality of digital control points, such as points 62a-62i in Fig. 3 in response to a digital image data stream 60 received from engraver controller 38.
  • the engraver controller 38 receives the digital image data stream 60 from the image processing computer 40 (Fig. 1) mentioned earlier herein.
  • the method and apparatus for generating the control points from digital image data and generating an engraving toolpath in response to those control points will now be described relative to Figs. 2- 6.
  • the processor 42 comprises the toolpath controller 44 comprising generating means or a generator 46 for receiving the digital image data from controller 38 and for generating a plurality of control points, such as the aforementioned control points 62a-62i shown in Fig. 3.
  • the generator 46 receives the image data in the form of the stream 60
  • Fig. 3 of digital density values, such as the density values identified as 60a, 60b ... 601 in Fig. 3.
  • the density values are represented as a percentage, with 0% density representing a white or non-engraved area and 100% density representing a full black engraved area.
  • the stream 60 of digital density values comprises four (4) data values for each area to be engraved.
  • the control point generator 46 receives the data values and generates the plurality of control points 62a-62i (Fig. 3) in response thereto.
  • the image data values 60a- 60d from image data stream 60 are received by the generator 46 and a plurality of corresponding control points 62a-62c are generated in response thereto.
  • the toolpath controller 42 also comprises a curve fitter/toolpath generator 48 which receives the plurality of control points 62a-62i and generates a toolpath, such as toolpath 64 in Fig. 3, in response thereto.
  • a curve fitter/toolpath generator 48 which receives the plurality of control points 62a-62i and generates a toolpath, such as toolpath 64 in Fig. 3, in response thereto.
  • the portion 64a of the toolpath 64 is generated using the generated control points 62a-62c.
  • the portion 64b and 64c of toolpath 64 are generated using the control points 62d-62f and 62g-62i, respectively.
  • the curve fitter/toolpath generator 48 comprises a cubic spline interpolator or curve fitting routine or means resident in suitable memory (not shown) of the processor 42 for receiving the control points, such as points 62a-62i, and for generating the toolpath 64 in response thereto.
  • the generator 48 breaks the toolpath 64 into 32 discrete data segments, one of which is illustrated as 64d in Fig. 3. These 32 discrete data segments are ultimately transmitted to the tuning processor 52 as described later herein.
  • curve fitting techniques shown and described in the Numeric Recipes in C the Art of Scientific Computin , second edition, Cambridge University Press, Section 3.3- Cubic Spline Interprelation may be used to apply a curve to the control points being processed.
  • the digital signal processor 42 and toolpath controller 44 further comprises synchronizing means or synchronization routine 50 for receiving machine synchronization signals from engraving controller 38 and for synchronizing the digital toolpath 64 to the rotation of the cylinder 24.
  • the operation of the control point generator 46, toolpath generator 48 and synchronization routine 50 will now be described relative to Figs. 5A, 5B and 6.
  • control point generator 46 segments data values 60a-60l into groups of four and determines whether each of the four (4) image data values, such as values 60a-60d in Fig. 3, represent a continuous tone ("CT") image.
  • CT continuous tone
  • the image data values 60a-60d comprise an image intensity value and an indicator which distinguishes the source of the data as either "CT” or "LW” . If the decision at decision block 80 is negative, then the image data value received by control point generator 46 from controller 38 represents a linework (“LW”) image.
  • the control point generator 46 selects (block 81) appropriate setup values (not shown) for use in processing the LW image data value.
  • the setup values used in this processing comprise the AC gain, DC gain, and offset values as taught in OEE patents 5,424,848 and 5,621,533 which are incorporated herein by reference and made apart hereof. If the decision at decision block 80 is yes, then the image data value represents a CT image and the routine proceeds to block 82 where it selects CT setup values for use by control point generator 46.
  • control point generator 46 determines a plurality of sealers which are used to scale the image data values 60a-60d (Fig. 3)
  • the control point generator 46 first determines or computes a full cell depth sealer (block 84) using the CT setup values, and a channel depth sealer (block 86) for CT is also computed using the CT setup values.
  • a full cell depth sealer for LW and a channel depth sealer for LW, respectively, are computed.
  • control point generator 46 computes a total percentage density of the sum of four (4) image data values.
  • decision block 94 it is determined whether the total density is less than one percent (1%) , thereby indicating a non-engraved area. If it is, then the routine proceeds to block 96 where control point generator 46 assigns and stores control points which will cause stylus 30 to be situated above surface 24a of cylinder 24 during actual engraving. Thereafter, the routine is complete. If the decision at decision block 94 is negative, then the routine proceeds to decision block 98 (Fig. 5B) where it is determined whether a multiple frequency cell or engraved area is required.
  • the multiple frequency decision (block 98) is yes if both the conditions exist where the first data value is greater than the sum of the second and third data value (for example, 60a > (60b + 60c) ) and the fourth data value is greater than the sum of the second data value and the third data value (for example, 60d . (60b + 60c)).
  • Fig. 4 illustrates another stream 66 of image data values comprising a plurality of density values 66a- 661. Notice in the illustration being shown in Fig. 4 that density values 66e-66h show density values from black (100%) to white (0%) to white (0%) to black (100%) , thereby indicating multiple frequency engraved areas because 66e > (66f + 66g) and 66h > (66f + 66g) .
  • the engraved areas represented by these density values are illustrated by the engraved areas 65a and 65b defined by a toolpath 65 which was generated using the density values 66a-661.
  • the generation and procedure for generating toolpath 65 (Fig. 4) representing multiple engraved areas is described later herein. If the answer at decision block 98 (Fig. 4) (Fig.
  • an entry control point or location and depth is determined.
  • an entry point such as point 62a in Fig. 3
  • an entry depth is determined by applying the appropriate CT or LW channel sealer to the first image data value, which in this example is 60a.
  • the depth Ed is the depth at which stylus 30 will penetrate surface 24a.
  • a center point location 62b and center point depth is determined.
  • the center depth Cd is determined by applying the full depth sealer to the previously computed total % density (block 102 in Fig.
  • the center point location is determined by computing the center of image density of data values 60a-60d and locating control point 62b such that an equal amount of density is left and right of 62b.
  • the center of the engraved cell is shifted towards the denser image data values to improve reproduced image quality.
  • This feature is illustrated relative to engraved area 75 in Fig. 4A and its associated control point 71a-71c.
  • the routine continues to block 104 where an exit point location (identified as point 62c in Fig. 3) and an associated exit depth Exd is determined at block 104. Thereafter, the routine is complete.
  • control point generator 46 proceeds to generate control points, such as points 70a, 70b and 70c for the first subset of image data values 66e and 66f and control points 70d, 70e and 70f for the second image data subset represented by density values 66g and 66h.
  • control point generator 46 computes a total density for the first pair of data values, such as data values 66e and 66f in Fig. 4.
  • the routine proceeds to block 108 where control point generator 46 determines a center of image density for this first pair of data values.
  • control point generator 46 determines a first entry control point location, such as control point 70a shown in Fig. 4, and associated entry depth.
  • the first entry point depth is determined using the first data value 66e and applying the channel depth sealer thereto.
  • control point generator 46 determines a first center point location (point 70b in Fig. 4) and depth.
  • the first center point 70b is placed at the center of image density and its associated depth is set by applying the full depth sealer to the % total density for the first pair of data values 66e and 66f.
  • a first exit location (point 70c) and associated depth is determined.
  • the stylus 30 exits the surface 24a at exit point 70c.
  • This point 70c is a distance O 1 (Fig. 4) away from a starting point SP.
  • This distance Dl varies relative to the total distance D 2 in the same proportion as the total percent density computed at block 106 in Fig. 5B.
  • control point generator 46 then proceeds to determine the control points 70d-70f associated with the second image data value subset (values 66g and 66h in the illustration shown in Fig. 4) . Accordingly, at block 116 (Fig. 5B) , control point generator 46 determines a total density for the second pair of data values 66g and 66h. At block 118, the control point generator 46 locates a center of the image density for the second image data subset. At block 120, a second entry location and depth control point (point 70d in Fig. 4) is then determined. The stylus 30 enters the surface 24a at entry point 70d. This point 70d is a distance D 3 (Fig. 4) away from an ending point EP . This distance D 3 varies relative to the total distance D 2 in the same proportion as the total percent density computed at block 116 in Fig. 5B .
  • the routine proceeds to block 122 (Fig. 5B) where a second center location (point 70e) and depth control point are determined.
  • the second center point 70e (Fig. 4) is placed at a center of image density of the second pair of data values 66g and 66h.
  • the second center point depth is set by applying the full depth sealer (determined at block 84 for CT data or 88 for LW data in Fig. 5A) to the percent total density (block 116 in Fig. 5B) for the second pair of data values 66g and 66h.
  • a second exit location (point 70f) and depth control is determined.
  • the second exit point 70f depth is determined using the last data value 66h and applying the channel depth sealer (block 86 or 90 in Fig. 5A) .
  • control point generator 46 Once all control points 70a-70f are generated by control point generator 46, they are transmitted to the curve fitter/toolpath generator 48 which processes the generated control points 70a-70f which are stored in memory, such as a control point buffer (not shown) .
  • Control point generator 46 interpolates or "fits" a corresponding curve to the control points 70a-70f in order to generate the toolpath (such as toolpath 65 in Fig. 4) .
  • This toolpath 65 is stored in memory, such as output buffer (not shown) and will subsequently be used to generate an engraving drive signal for energizing engraving head 28.
  • the digital signal processor 42 also comprises the synchronization means or synchronization routine 50 mentioned earlier herein for receiving machine synchronization signals from engraving controller 38 and for synchronizing the generated toolpath, such as toolpaths 64 or 65, with the engraver 10.
  • the synchronization routine will now be described relative to Fig. 6.
  • the routine begins at block 126 by reading a section, such as section 64d (Fig. 3) of the toolpath 64.
  • the routine transmits the generated toolpath to the tuning processor 52 (Fig. 2) for use in the manner described later herein (block 128 in Fig. 6) .
  • the routine also collects incoming image data stream 60 and initiates generation of, for example, toolpath 64 in response thereto. It should also be appreciated that the routine receives from controller 38 image data 60 at a rate of 4 data values (e.g., values 60a-60d in Fig. 3) for each single frequency engraved area, such as area 67 (Fig. 3) . Substantially simultaneously therewith, the routine transmits toolpath 64 data to the tuning processor 52 at a rate of 32 data values or segments (such as segment 64d in Fig. 3) per single frequency engraved area (such as area 67 in Fig. 3) .
  • data values e.g., values 60a-60d in Fig. 3
  • the routine transmits toolpath 64 data to the tuning processor 52 at a rate of 32 data values or segments (such as segment 64d in Fig. 3) per single frequency engraved area (such as area 67 in Fig. 3) .
  • image data stream 60 (Fig. 3) is received from controller 38 at 4 data values (e.g., 60a-60d) per single frequency engraved area .
  • the image data such as data 60a- 60d
  • the routine proceeds to block 136 (Fig. 6) where the data values 60a-60d are processed into the control points 62a-62c using the aforementioned control point generator 46 in the manner described earlier herein relative to Figs. 5A and 5B .
  • the control points are further processed into the toolpath, such as toolpath 64 in Fig. 3, by toolpath generator 48 as described earlier herein.
  • the synchronization routine or means is complete and the toolpath is synchronized with the operation of the engraver 10.
  • this invention synthesizes the digital image data stream 60 and the traditional screening function into a reference toolpath or waveform which represents the desired toolpath to be followed by stylus 30.
  • the screening traditionally used is synthesized directly from the digital image data, thereby allowing much greater flexibility and improvement in engraving quality.
  • the image data is transformed into the above-mentioned control points at which the stylus 30 is to enter (point 62a in Fig. 3), reach maximum depth (point 62b in Fig. 3), and exit (point 62c in Fig. 3) for each area (like area 67 in Fig. 3) to be engraved.
  • control points are thereafter used by the curve fitter/toolpath generator 48 to generate, interpolate or "fit" the toolpath, such as toolpath 64, to define the engraving path with the stylus 30 will follow.
  • the toolpath 64 will be generated and used as the stylus 30 toolpath derived directly from the digital image data.
  • a further feature of the invention is that the apparatus and method of the present invention facilitates digitally distorting the generated toolpath, for example, in order to shift one or more centers of engraved areas or partial engraved areas, particularly at the edges of an image (not shown) .
  • the image values 69a-69d represent 100% (full black) , 100% (full black), 0% and 0% densities.
  • Most engraving systems of the past may average these densities to produce a cell (not shown) having 50% density which is generally in the center of region 74.
  • the present invention and control point generator 46 evaluates the image data and generates corresponding control points 71a-71c as shown. These control points 71a-71c are then used by toolpath generator 48 to generate the toolpath curve 73. Notice that the toolpath defines a shifted engraved area 75 which more accurately corresponds to the image data 69a and 69b originally input.
  • a kanjii character pattern X is engraved using conventional engraving techniques.
  • pattern Y (Fig. 16) is engraved using the apparatus and method of the present invention. Notice the horizontal lines XI and Yl (as viewed in Fig. 16) exhibit improved placement of engraved areas achieved by the shifting of an engraved area or a portion thereof away from locations such as X2 which would be required by traditional engraving techniques .
  • the invention further provides tuning means, tuning processor, tuner or a tuning system 52 (Fig. 2) and method for calibrating and tuning the engraving head 28 such that it will track the generated toolpath in a desired or accurate manner.
  • the tuner 52 is coupled to the engraving head 28 via amplifier 53 which amplifies the engraving signal received from tuner 52 for moving energizing stylus 30 on engraving head 28.
  • Fig. 9 illustrates a raw engraving head response characteristic 53 showing a plurality of peaks, such as peaks 53a and 53b, associated with a first resonance and a second resonance, respectively, of engraving head 28.
  • the first and second resonances typically occur around 1800 KHz and about 5500 KHz, respectively, for a typical engraving head 28.
  • a typical engraving system comprises a plurality of notch filters situated on the engraving head 28 which eliminate the aforementioned first and second resonances to provide a response characteristic 57 which is generally smooth, but substantially continuously decreasing, as shown in Fig.10.
  • the apparatus and method of the present invention comprises emphasis filtering means or an emphasis filter 56 for processing the engraving signal to provide a substantially constant gain or linear response characteristic of the type shown by the response characteristic 58 in Fig. 11.
  • the response characteristic 58 is substantially linear across a greater frequency range to provide a substantially constant gain for frequencies approaching or less than about 10,000 KHz.
  • the apparatus and method of the present invention achieves the foregoing by boosting the engraving signal at frequencies in excess of an emphasis frequency which in the embodiment being described is at least 1 KHz.
  • tuning means 52 comprises at least one or a plurality filters 54 and 56 which processes or filters the toolpath (such as toolpath 64 in Fig. 3) generated by the digital signal processor 42.
  • the notch filters 54 process the toolpath 64 to eliminate the first and second resonances mentioned above, the emphasis filter 56 is applied to filter the signal to provide the response characteristic 58 shown in Fig. 11.
  • the notch filtering may be achieved by a single infinite impulse response filter algorithm implemented on a digital signal processor such as an ADSP21062 available from Analog Devices, Inc. of One Technology Way, P.O. Box 9106,
  • a second infinite impulse of response filter may be provided to implement the emphasis filtering of the present invention.
  • An algorithm which may be used to implement the notch and emphasis filtering achieved by filters 54 and 56 is the infinite impulse response (IIR) bi-quad filter as described in the analog devices ADSP-21000 Application Handbook, Volume 1, Section 4.2 -IIR Filters, available from Analog Devices, Inc. of Norwood, MA and published in May, 1994.
  • IIR infinite impulse response
  • the emphasis filter 56 provides a substantially linear or flattened frequency response (response 58 in Fig. 11) such that the response of the engraving head 28 achieves the same amplitude across a larger frequency range. This is particularly beneficial when engraving or implementing double frequency engraved areas of the type shown and described above relative to Fig. 4 because the filtered engraving head 28 must achieve at least 50% of the maximum amplitude at, for example, a frequency of 10 KHz as s own .
  • tuning means 52 further comprises a tuning computer, interface means or a user interface 150 (Fig. 2) for configuring both notch filter 54 and the emphasis filter 56.
  • This interface 150 may comprise an IBM or IBM compatible PC running application software which generates an interactive interface screen 150a (Fig. 12) .
  • the user interface screen 150a may comprise a window 150b for inputting and/or adjusting parameters for the notch filters 54 and emphasis filter 56.
  • the filter parameters comprises a frequency value 152 and a notch depth value 154 for each of the notch filters 54.
  • a similar user interface screen (not shown) is also provided for similar filter parameters values for emphasis filter 56.
  • the user interface 150 (Fig. 2) converts the parameter information into filter coefficients using the following coefficient formulas:
  • FREQ is the frequency value input by the user via user interface 150 (Fig. 2) ;
  • DAMP is the filter 54 and 56 damping value input by the user via user interface 150.
  • the calculated coefficients C and C 2 are then used to electronically set or adjust the actual coefficients of the notch filters 150 and 152.
  • this invention provides means for permitting a user to interactively program or adjust the filter coefficient values, thereby permitting the user to electronically program or change the frequency characteristic of the engraving head 28, without changing the hardware, such as the filters, associated with the engraving head 28.
  • the engraving system 10 further comprises a digital closed-loop feedback means or feedback controller 156 (Fig. 2) which assists in achieving a stable engraving head 28 by implementing electronic dampening of the natural resonances of the engraving head 28.
  • the feedback controller 156 is coupled to a sensing circuit 158 (Fig. 14) which senses and feeds a position of stylus 30 and a stylus 30 velocity to the feedback controller 156 (Fig. 2) .
  • FIG. 13 shows a sectional view of a typical armature 170 which is rigidly secured to a shaft 172 and projects outwardly between a pair of electromagnets 174 which are mounted within a base of the engraving head 28, as taught for example in U.S. Patent Nos. 5,029,011; 4,450,486; 4,438,460; and 4,357,633 all of which are assigned to the same assignee as the present invention and incorporated herein by reference and made a part hereof.
  • the armature 170 cooperates with the electromagnets 174 to define air gaps 176.
  • the electromagnets 174 when the electromagnets 174 are energized by an alternating current, the armature 170 and shaft oscillates to a maximum arc of approximately 0.25 degree and at a frequency of, for example, between 3-5 KHz.
  • the stylus 30 is secured to the shaft 172 via a support arm (not shown) , and consequently, oscillates in response to the oscillation of the shaft 172.
  • Energization of the electromagnets 174 is achieved in a conventional manner using the windings 178.
  • the sensing circuit 158 comprises a second set of windings 180 around electromagnets 174.
  • the windings 180 comprise a sensing coil for measuring the magnetic flux present in the electromagnet of the armature 170 which the feedback controller/means 156 uses to convert into an actual position of the stylus 30.
  • the magnetic flux present in the electromagnet is the sum of two sources, the drive windings 178 and the flux induced due to the motion of the armature.
  • Windings 180 detect the magnetic flux present in the motor and an electronic circuit (158 in Fig. 14) subtracts the flux due to the windings 178 to yield the component of the flux due to the velocity of the armature 170.
  • the means or circuit 158 comprises a current sensing resistor 182 which is situated between ground and a low (-) side of engraving head 28 as shown.
  • the circuit 158 also comprises a receiver amplifier 184 which is coupled to a head drive high (+) winding 178A (Fig. 13) and head drive low (-) winding 178B to provide an amplified signal which is integrated by integrating amplifier 186. The resulting integrated signal is transmitted as one input to a summing amplifier 188 as shown in Fig. 14.
  • the circuit 158 also comprises receiving amplifier 190 is coupled to a head sense high (+) side 180A in Fig. 13 and a head sense low (-) (180B in Fig. 13) and across current sensor resistor 182 (Fig. 14) as shown.
  • the receiving amplifier 190 receives the measured signals and generates an amplified output signal which is received as a second input by summing amplifier 188 and the sole input of a differentiator amplifier 192 as shown .
  • the outputs of differentiator amplifier 192 and receiving amplifier 184 is received by summing amplifier 194.
  • Summing amplifiers 188 and 194 each sum their respective inputs received and generate or output a position signal and velocity signal, respectively. It has been found that the position signal and velocity signal correlate with the position and velocity of the armature 170 and stylus 30.
  • These sensed signals are fed back to a user interface decoder 154 (Fig. 2) .
  • the interface decoder 154 provides engraving head 28 response data to the user via the user interface 150 in the manner described earlier herein.
  • the system and method of the invention comprise means for providing interactive and automated tuning of engraving head 28 which will now be described relative to Figs. 7 and 8.
  • the routine begins at block 200 where tuning processor 52 receives the most recently transmitted value for toolpath 64 from toolpath controller 42.
  • the routine proceeds to block 202 where the toolpath value is processed by notch filter 54 using the tuning filter coefficients generated by user interface 150 using predetermined coefficients or filter coefficients generated in response to parameters input by a user via user interface 150.
  • the routine further processes the toolpath value with emphasis filter 56 using the emphasis filter coefficients input via user interface 150 using predetermined coefficients or filter coefficients generated in response to parameters input by a user via user interface 150.
  • a user has input a tuning parameter update command by inputting a new or different parameter using user interface 150a in which case the new filter coefficients for the filter 54 generated by the user interface 150 are stored (block 209 in Fig. 7) by the tuning processor 52 in an appropriate buffer (not shown) . If the decision at decision block 206 is negative, then the routine proceeds to block 208 where it is determined whether a user has input new emphasis filter parameters, thereby indicating an emphasis filter 56 update command. If it does, then the routine proceeds to block 210 where new emphasis filter coefficients generated by user interface 150 are stored by tuning processor 140 in a suitable buffer (not shown) .
  • the routine proceeds to decision block 212 where it is determined whether a head response test command has been received by interface decoder 154 from user interface 150. If it has, then the routine proceeds to test the engraving head 28 using a test pattern which is sent to the engraving head 28. During such testing, the feedback controller/means 156 generates feedback or sensed information regarding the actual position and velocity of stylus 30 in the manner described earlier herein. The sensed position and velocity data are fed back to the interface decoder 154 and ultimately to user interface 150 in a manner described later relative to Fig. 8.
  • Fig. 8 illustrates the interactive/automated tuning user interface means or routine which begins at block 220 where information is input by a user via the user interface 150.
  • information may include, for example, an automatic tuning request, filter parameter information, such as filter notch depth, filter frequency change requests and/or a head response request command mentioned above for ascertaining the responsiveness of engraving head 28.
  • user interface screen 150a may comprise electronic buttons (not shown) for permitting an operator to select or input these various commands .
  • the routine proceeds to decision block 222 where it is determined if a user has input a request to change a frequency or notch depth of filter 54. If it has, then the routine proceeds to block 224 where the user interface computer 150 recomputes filter coefficients for the filter 54 and sends it to tuning processor 52 and then exits. As mentioned earlier herein, Fig. 12 shows one suitable user interface 150a for permitting the user to input such information. If the decision at decision block 222 is negative, then the routine proceeds to block 226 where it is determined whether the emphasis filter 56 frequency change has been requested by the user. If it has, then the routine proceeds to block 228 where user interface 150 recomputes the filter coefficients in response to the new frequency input by the user and sends it to tuning processor 52 and then exits. Following the recomputations of the filter coefficients for filters 54 and 56, interface 150 sends the new notch filter coefficients and emphasis filter coefficients to the notch filters 54 and emphasis filter 56 in order to electronically adjust the filters 54 and 56 in response thereto as described earlier herein.
  • the routine proceeds to decision block 230 where it is determined if the user has input an automatic tuning request. If it has, then the interface decoder 154 sends the command to perform a head response test to the feedback controller/means 156 (block 232) . At this point, tuning processor 52 stops processing actual toolpath data received on line 52a from toolpath controller 44 and begins processing test pattern data stored in memory of tuning processor 52.
  • feedback controller ⁇ means 156 receives sensed and actual position of stylus 30, as sensed by sensors 158 (Fig. 14) in the manner described earlier herein. This information is transmitted back to the decoder 154 and to user interface computer 150 for display and evaluation (block 234) . If the user interface computer 150 determines that an unacceptable difference of actual stylus 30 response and desired stylus 30 response exists, then the user interface computer 150 electronically recomputes and adjusts the filter coefficients C ⁇ and C 2 in response thereto (block 236) .
  • this invention provides means and methods for automatically tuning an engraving head 28 in response to an automatic tuning request initiated by a user.
  • new and/or adjusted filter coefficients are sent to filters 54 and 56, thereby automatically adjusting the response characteristic 58 (Fig. 11) .
  • the routine terminates.
  • Fig. 15 provides a schematic illustration of an overall method of operation which begins on system power- up which, in turn, starts the toolpath controller 44 (block 240) , tuning processor 140 (block 242) and interactive/automated tuning computer 150 (block 244) .
  • decision block 246 it is determined if a user has input a tuning modification request and if he has not, then the routine loops back as shown (decision block 246) . If the decision at decision block 246 is yes, then the routine proceeds to block 248 where the user interface routine (described relative to Fig. 8) is performed. Thereafter, the routine loops back to decision block 246 as shown.
  • Tuning processor 52 comprises an internal clock or timer (not shown) which is timed to periodically expire 200,000 times per second. At decision block 250, if it is determined that the timer has expired, then the routine proceeds to block 252 where the tuning processor routine described relative to Fig. 7 is performed. Thereafter or if the decision at decision block 250 is negative, the routine loops back to decision block 250 as shown .
  • decision block 254 it is determined whether a machine synchronization signal (not shown) has been received by digital signal processor 42 from engraving controller 38. If it has, then the toolpath controller synchronization routine described above relative to Fig. 6 is performed. Thereafter or if the decision at decision block 254 is negative, the routine loops back to block 254 as shown.

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Abstract

L'invention est caractérisée en ce que l'on utilise un programme et un système pour fournir directement plusieurs points de contrôle à partir de données d'image représentant une image à graver. Ces points permettent d'établir une trajectoire d'outil qui, à son tour, va servir à exciter une tête de gravure de sorte qu'un outil ou un stylet grave une configuration de zones de gravure suivant la trajectoire d'outil. L'invention concerne un système et un procédé pour la gravure d'au moins une zone de gravure, avec dispositif de réglage de tête de gravure conçu pour régler une tête de gravure de manière à ce que la courbe de réponse en fonction de la fréquence de cette tête définisse un gain sensiblement constant pour les fréquences inférieures à une fréquence prédéterminée. L'invention concerne également un système et un procédé offrant les possibilités suivantes: réglage interactif et automatique de la tête de gravure, ajustement interactif des caractéristiques de filtre (y compris les coefficients de filtrage pour les filtres utilisés sur la tête de gravure) et fonctionnement réagissant aux types de données d'image (en ton continu ou en trait). L'invention est caractérisée en ce qu'elle permet de synthétiser la fonction de balayage pour reproduire plus précisément l'image à graver, par gravure de plusieurs cellules de fréquence là où l'état antérieur de la technique permettait la gravure de cellules uniques.
PCT/US1998/010674 1997-05-30 1998-05-26 Systeme et procede pour la gravure avec controle de trajectoire d'outil arbitraire WO1998053993A1 (fr)

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JP5794393B2 (ja) * 2012-09-25 2015-10-14 日産自動車株式会社 操舵制御装置

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US5229861A (en) * 1989-05-24 1993-07-20 Dai Nippon Insatsu Kabushiki Kaisha Electronic gravure engraving apparatus including photo tone and character/solid tone processing
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CN110103621A (zh) * 2019-06-06 2019-08-09 北部湾大学 一种大型陶瓷自动雕刻机
CN110103621B (zh) * 2019-06-06 2024-05-14 北部湾大学 一种大型陶瓷自动雕刻机

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JP3476795B2 (ja) 2003-12-10
DE19823792A1 (de) 1998-12-10
JP2002079644A (ja) 2002-03-19

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