JP2006349547A - Noncontact type three-dimensional shape measuring method and measuring machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noncontact type three-dimensional shape measuring method using such a conversion that noncontact type position sensor is attached as a substituting component, in consideration of utilizing a triaxial moving mechanism or the like of a contact type three-dimensional shape measuring machine as a noncontact type component. <P>SOLUTION: Original position calibration data representing a relation between the original position of the noncontact type position sensor 29 and the original position of a head 6 of the contact type three-dimensional shape measuring machine to which a contact type probe is attached fundamentally, are prepared, and commands including a motion start position and a motion end position in a motion range of the triaxial moving mechanism 8 are issued sequentially so as to drive and control driving means 7x, 7y and 7z, and in a process of moving and scanning the head 6, trigger commands are issued to the noncontact type position sensor 29 at a prescribed cycle period, and the original position of the head 6 defined by the motion start position, the motion end position and each motion position at the cycle period, is calibrated so as to correspond to the original position calibration data, and the original position of the noncontact type position sensor 8 is acquired, and then three-dimensional shape data of a car body 9 which is an object to be measured are obtained by noncontact detected position data of the noncontact type position sensor 8 on the original position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention measures a three-dimensional shape in a non-contact manner by using a measuring instrument that measures a three-dimensional shape in a contact manner by attaching a contact probe to a three-axis moving mechanism that moves in directions orthogonal to each other and moving and scanning. It is related with the non-contact-type three-dimensional shape measuring method for diverting, and the diverted measuring machine.

According to Patent Document 1, etc., a contact-type three-dimensional measurement that measures a three-dimensional shape by bringing a stylus supported by a three-axis moving mechanism that moves in three axial directions perpendicular to each other into contact with a measurement object while sequentially moving the stylus. Shape measuring devices are well known. Further, according to Patent Document 2 and the like, a non-contact type measuring apparatus that moves and scans a laser distance sensor in a planar shape with a triaxial moving mechanism is also well known.
Japanese Patent Laid-Open No. 10-19504 JP-A-6-249626

  According to the latter non-contact type, it is possible to perform high-speed measurement in a consistent manner by being able to move and scan without bringing the sensor into contact with the measurement object. However, when a contact-type three-dimensional shape measuring machine is already installed, if it is attempted to introduce a non-contact type three-dimensional shape measuring machine in order to increase the speed, the equipment cost will increase accordingly.

  The present invention pays attention to the fact that the three-axis moving mechanism of a contact type three-dimensional shape measuring machine can be used as a non-contact type, and a non-contact type three-dimensional shape measuring method based on diversion of the contact type three-dimensional shape measuring machine. And to provide a measuring instrument.

  In order to achieve this object, the present invention provides, according to claim 1, a head to which a contact-type probe is attached, and supports the head, and faces the measurement object in the horizontal direction, the vertical direction, and orthogonal to these axes. A three-axis movement mechanism that moves in a moving direction, a movement position sensor that detects the movement position of each of the three axes, and a drive unit that drives the three-axis movement mechanism to the commanded movement position so as to move and scan the head. By providing, the contact type that measures the three-dimensional shape by sequentially detecting the three-dimensional position of the measurement object based on the detection signal of the movement position sensor when the contact type probe contacts the measurement object A non-contact type position sensor that detects the position of a predetermined two-dimensional or three-dimensional detection range is attached to the head instead of the contact type probe, and the three-dimensional shape is measured in a non-contact type. 3 is a non-contact type three-dimensional shape measuring method for diverting to the above, wherein the origin calibration data of the origin position of the non-contact type position sensor with respect to the origin position of the head is created in advance, and the drive means is driven and controlled. The movement start end position and the movement end position of the movement range of the axis movement mechanism are sequentially commanded, and a trigger command is given to the non-contact type position sensor at a predetermined repetition period during the head movement scanning process. In addition, the origin position of the non-contact position sensor is determined by calibrating the origin position of the head defined by the movement position for each repetition cycle in accordance with the origin calibration data, and the non-contact position sensor is not contacted at this origin position. It is characterized in that three-dimensional shape data of the measurement object is created from the detected position data.

  With respect to the three-axis movement mechanism, the movement start and end positions are each commanded with one coordinate value or at least one coordinate value for each of the three axes, and the three-axis movement mechanism for moving and scanning the head moves each movement range. Move from start to end. Meanwhile, the detection signal of the movement position sensor is derived for each trigger command of the non-contact type position sensor, and the non-contact type position sensor detects the position each time. The origin position of the non-contact position sensor is calibrated with respect to the origin position of the head, which is the origin of the contact probe, and the three-dimensional shape of the scanning range is measured by the non-contact detection position group at the calibrated origin position. The

  At that time, as a simple diversion method, according to the invention of claim 2, the movement position sensor of the contact type three-dimensional shape measuring instrument is an incremental linear scale, and the origin position of the non-contact type position sensor is the commanded start end position. And the calibrated origin position defined by the movement end position and the count value for each repetition period from the movement start position of the linear scale to the movement end position. In order to make the mounting position of the non-contact type position sensor freely, according to the invention of claim 3, the head is rolled and pitched with respect to a horizontal direction facing the measurement object and a horizontal axis perpendicular to the horizontal direction. It is rotatable and the origin position of the head and the origin position of the non-contact type position sensor are calibrated according to the rolling and pitching rotation angles, respectively. As the non-contact type position sensor, according to the invention of claim 4, the non-contact type position sensor can use a laser sensor that detects a distance in a predetermined two-dimensional range by a sector scan to the laser beam.

  According to claim 5, an apparatus for performing the method of claim 1 includes origin calibration data storage means for storing origin calibration data for calibrating the origin position of the non-contact position sensor with respect to the origin position of the head; A movement range command means for sequentially commanding the movement start end position and the movement end position of the movement range of the three-axis movement mechanism so as to control the drive means, and a non-contact type position sensor in a predetermined repetition manner during the head movement scanning process. Detection command means for issuing a trigger command at a period; movement position data creation means for creating movement position data for three axes within a movement range in response to a detection signal of the movement position sensor for each repetition period; and the movement start end position data And the movement end position data and the origin position data of the head defined by the movement position data are calibrated corresponding to the origin calibration data, and the non-contact Shape data creating means for creating origin position data of the position sensor, and creating three-dimensional shape data of the measurement object based on the non-contact detection position data of the non-contact position sensor for the origin position data. It is characterized by that. At this time, for easy diversion, according to the invention of claim 6, the movement position sensor of the contact type three-dimensional shape measuring instrument is an incremental linear scale, and the shape data creation means is the origin of the non-contact type position sensor. The position data includes the calibrated origin position data defined by the commanded movement start position data and movement end position data, and movement position data that is a count value for each repetition cycle of the linear scale between the movement start position and the movement end position. Created with the origin position data specified in.

  According to the first or fifth aspect of the invention, the three-axis moving mechanism of the contact type three-dimensional shape measuring instrument is continuously operated in the unit scanning range by remodeling or adding the circuit device portion of the contact type three-dimensional shape measuring instrument. Along with the movement, the detection signal of the movement position sensor is derived, and non-contact type three-dimensional shape measurement is possible by the movement position based on the detection signal at the sampling time and the non-contact detection position of the non-contact type position sensor Become. That is, it is possible to divert from the contact type to the non-contact type while saving the equipment cost. In that case, according to the invention of claim 2 or claim 6, it is assumed that the contact-type three-dimensional shape measuring machine is provided with an incremental linear scale as a movement position sensor, and that the non-contact is obtained by taking the detection signal. The three-dimensional shape measurement data of the formula can be created by a simpler additional circuit. According to the invention of claim 3, even if the head of the contact probe is rotatable, it can be diverted, and according to the invention of claim 4, belt-like measurement data can be obtained per unit scanning range.

  A measuring machine that implements a non-contact type three-dimensional shape measuring method according to an embodiment of the present invention will be described with reference to FIGS. The contact-type three-dimensional shape measuring machine is configured to support a rotary head 6 on which a contact-type probe 39 having a pressure-sensitive element shown in FIG. For example, it is arrange | positioned at the both sides of the base 1 on which the vehicle body 9 is mounted as a measurement object. This three-axis movement mechanism includes, for example, guide rails 2 in the X-axis direction disposed on both sides of a base 1 on which a vehicle body 9 is placed as a measurement object, and a head 6 at a tip portion. A rod-shaped sensor support carriage 4 that is movable along the horizontal Y axis that is in contact with and away from the vehicle, and is guided by the guide rail 2 so as to be movable in the X axis direction while being guided up and down along the vertical Z axis. And a slider type carriage 3.

  The guide rail 2 incorporates an X-axis movement mechanism with a linear scale 5x and an actuator 6x as movement position sensors, and is driven by the drive means 7x so that the movement position detection signal coincides with the command signal. The slider carriage 3 incorporates a Z-axis moving mechanism that moves the sensor support carriage 4 up and down in the Z-axis direction, and includes a linear scale 5z and an actuator 6z, and is similarly servo-controlled by the driving means 7z. Further, the slider carriage 3 has a built-in Y-axis moving mechanism for moving the sensor support carriage 4 back and forth in the Y-axis direction, is attached with a linear scale 5y and an actuator 6y, and is servo-controlled by the driving means 7y.

  The base of the head 6 to which the contact type probe 39 is attached is capable of rotating by pitching around an axis along the X axis and rolling by rotating around an axis along the Y axis. The three-dimensional shape is measured in a contact manner by appropriately setting and moving the three-axis movement mechanism 8 in a planar shape while sequentially bringing the contact probe 39 into contact with the measurement object.

  In order to divert such a contact type three-dimensional shape measuring machine to a non-contact type, the position or shape of a linear two-dimensional range of about 10 cm is detected on the head 6 by, for example, fan scanning of a laser beam based on the principle of triangulation. A non-contact position sensor 29 is attached instead, and the personal computer 10 is attached as a circuit device for controlling them. This personal computer shares a part of the program to be operated in a contact type, and the program is added to operate the built-in memory, CPU, etc. in a non-contact type to function as the following means. An input operation unit 11 such as a keyboard and a mouse, a display unit 12 and a printer 13 are attached. Such a non-contact type three-dimensional shape measuring machine is also arranged on the opposite side of the base 1.

  That is, in order to set the rotational position of the head 6 by servo control, the head position command means 28 that issues a rotational position command to the attached control unit 6 a and the head position that is the original origin position that is the rotational center position of the contact probe 39. Correction data storage means 23b for storing correction data corresponding to the mechanical error of the triaxial moving mechanism 8 and the non-contact type position sensor 29 by moving the head 6 relative to the vehicle body 9 The movement range command means 20 for sequentially instructing the drive means 7x, 7y, and 7z of the start end position and the end position of the movement range of the triaxial movement mechanism 8 and the triaxial movement mechanism 8 are instructed so as to move the detection range. In the process of moving to the end position, the detection command means 21 for issuing a trigger command to the control unit 29a attached to the non-contact type position sensor 29 at a predetermined repetition period, and the repetition period The moving position data generating means 22 for generating the moving position data of each of the three axes in the moving range in response to the count value in the counting unit 22a of the detection signals of the linear scales 5x, 5y, 5z, and the rotational position of the head 6 Origin calibration data storage means 26 for storing origin calibration data for calibrating the origin position of the non-contact type position sensor 29 with respect to the origin position of the defined head 6 and the start / end positions of the movement range are defined. The three-axis movement position is corrected with the correction data described above, and a three-dimensional coordinate value calibrated as the origin position of the non-contact type position sensor 29 is created. The origin position data of the non-contact type position sensor 29 is created based on the movement position data based on the count values of the linear scales 5x, 5y, and 5z that are equally divided. Shape data creation means 23 for creating three-dimensional shape data of the measurement object based on non-contact detection position data by the non-contact type position sensor 29 at each origin position, and shape data storage means 24 for storing the created three-dimensional shape data. And a display control means 25 for displaying the three-dimensional coordinate value of the three-dimensional shape as a point at a corresponding position on the two-dimensional screen or the virtual three-dimensional screen of the display unit 12.

  In the movement range command means 20, one start position and one end position are set in each of the three axis directions, and in some cases, the two axes are unchanged and are set only in the one axis direction. For example, the start end position and the end position can be set in the X-axis direction corresponding to the front-rear width of the vehicle body 9 and can be moved in the Y-axis direction according to the change shape of the body side surface along with the movement. Further, the next unit scanning range is set so that it is lowered in the Z-axis direction by an amount corresponding to the detection range of the non-contact type position sensor 29 at the end position and is moved back in the X-axis direction. Thereafter, similarly, the scanning is set so as to be moved and scanned in a planar manner within a plurality of unit scanning ranges. The moving range command means 20 that functions in this way can use a contact-type program. The movement range command unit 20 issues a movement position command and also creates difference data from the movement position detected by the movement position detection sensor, so that the driving units 7x, 7y, and 7z simply correspond to the difference data. It can also be configured to drive control.

  When the three-dimensional coordinate value of the origin position of the head 6, that is, the origin position of the original contact probe 39, is defined in the correction data storage unit 23 b based on the movement position of the three-axis movement mechanism 8. In consideration of a position error that varies slightly due to the influence of each deflection or temperature, correction data for the three-dimensional coordinate value of the origin position is stored for each predetermined movement range of each axis. Similarly, a contact-type program can be used.

  The detection command means 21 performs a trigger command for causing the control unit 29a attached to the non-contact position sensor 29 to operate each laser beam scanning with an external trigger at a predetermined repetition cycle. As a result, position data in a predetermined range in the Z-axis direction is detected each time, and surface scanning is performed in a band shape for the unit movement range. The repetition period is set so as to ensure a predetermined measurement accuracy corresponding to the detection speed by the laser beam and the movement speed of the triaxial movement mechanism 8. For example, the trigger command is set at a moving pitch of several hundred μm.

  The movement position data creation means 22 takes in the count value of the count unit 22a that counts the incremental signals of the linear scales 5x, 5y, and 5z that output pulses for each unit movement amount at every repetition cycle of the detection command means 21. Create the movement position data for the axis movement range for the time being.

  Since the origin position may vary depending on the rolling and pitching angle of the head 6, the origin calibration data storage means 26 stores the calibration data, and the origin calibration data storage means 26 is non-related to the varying origin position. An arithmetic expression for calibrating the three-dimensional coordinate value of the origin position of the contact position sensor 29 is stored as origin position calibration data. In particular, when the head 6 is non-rotating or has a narrow variable range, the conversion table can be simply stored as the origin position calibration data instead of the arithmetic expression.

  The shape data creating means 23 stores the rotation start / end position data from the movement range command means 20, correction data corresponding to the temperature of the correction data storage means 23b, and the rotational position commanded by the head position command means 28 in the data storage section 23a. The data is taken in, and the movement position data of the three axes of the movement position data creation means 22 is taken in. Then, with respect to the commanded movement start / end positions, error correction is performed with the correction data, and the origin position of the head 6 is tertiary according to the calibration data stored in the origin calibration data storage means 26 according to the rolling and pitching angles of the head 6. The original coordinate value is obtained, and then the three-dimensional coordinate value from the origin position of the head 6 to the origin position of the non-contact type position sensor 29 based on the arithmetic expression stored in the origin calibration data storage means 26 according to the rolling and pitching angles. To get. Further, the origin position data is created together with the three-axis movement position data created by the movement position data creation means 22 distributed in the meantime. Further, for each trigger command, non-contact detection position data in a predetermined range in the Z-axis direction of the non-contact position sensor 29 is fetched from the control unit 29a, and three-dimensional shape data of the belt-like scanning range is created and stored as shape data. Store in the means 24.

  Each time the head 6 reaches the end position of the moving scanning range, the display control means 25 displays the shape data defined by the three-dimensional coordinate values created for the unit scanning range and stored in the shape data storage means 24 on the display unit 12. Are plotted in a coordinate system on the screen, and a three-dimensional shape is displayed as a point group for each unit scanning range. Also, various images can be displayed by a selection operation on the input operation unit 11. For example, a three-dimensional shape combining a side surface and an upper surface is displayed on a virtual three-dimensional screen. When the measurement by the non-contact type three-dimensional shape measuring machines on both sides is completed, the entire shape of the vehicle body 9 is displayed in a rotary manner.

  The operation of the non-contact type three-dimensional shape measuring machine configured as described above will be described with reference to the flowchart of FIG. In the personal computer 10, the input operation unit 11 sets the start end position and the end position in order for each unit movement range in advance, and instructs the rotation position of the head 6. For example, the vehicle body 9 moves from the front side to the rear side along the X axis, and at the end, the vehicle body 9 is also moved slightly in the Y axis direction in accordance with the change in the side shape. Further, it is reciprocated in the X-axis direction while shifting in the Z-axis direction. Enter the ambient temperature for measurement. The rotational position of the head 6 can be changed according to the surface shape of the vehicle body 9 when the unit scanning range is switched.

  Next, when the operation start is instructed, the reset of the count unit 22a is initialized, and the origin position of the head 6 corresponding to the rolling and pitching angle of the head 6 is corrected for errors with respect to the movement start end position of the commanded movement range. A normal three-dimensional coordinate value calibrated as the origin position data of the non-contact type position sensor 29 is acquired from the origin position data of the original contact type probe 39. The head 6 starts moving scanning, and the non-contact position sensor 29 detects a position within a predetermined range in the Z-axis direction for each trigger command, and takes in the count values of the linear scales 5x, 5y, and 5z each time. Thus, the movement position data of the triaxial movement mechanism 8 is created for the movement scanning range with a fine movement pitch. When the movement end position is reached, error correction and calibrated three-dimensional coordinate values of the movement end position are acquired. The origin position data of the non-contact type position sensor 29 is created from the three-dimensional coordinate values of the start and end points and the movement position data that equally divides them. Thereby, the measurement data of the strip | belt-shaped three-dimensional shape with respect to the side surface of the vehicle body 9 is obtained according to the non-contact detection position data of the belonging Z-axis range on the basis of this origin position data. Incidentally, since the three-dimensional coordinate value is acquired from the original contact-type three-dimensional shape measuring instrument only when the contact-type probe 39 comes into contact, acquisition of the origin position data for each trigger command of the non-contact type position sensor 29 is acquired. Is impossible.

  Thereby, the shape data of the belt-shaped range is displayed as a point group at a position corresponding to each three-dimensional coordinate value in the coordinate system of the display unit 12. Measurement data is displayed in high density in a short time compared to the contact type. Hereinafter, the measurement data of the entire side surface is displayed by sequentially shifting the moving scanning range of the head 6. Similarly, the upper surface of the vehicle body 9 is also measured. It is also measured by the opposite non-contact type three-dimensional shape measuring machine, and when all the surfaces have been measured, the whole area of the vehicle body 9 is displayed on the virtual three-dimensional screen of the display unit 12 by combining the measurement data on the opposite side. This can be confirmed by rotating and displaying the shape.

  In the above-described embodiment, the rolling and pitching angles of the head 6 have been described as being set by servo control. However, in order to make the structure less bulky, the head 6 rotates in an open loop without a rotational position sensor. In the case of the method of controlling the angle, there is a possibility that the error becomes large, and the calibration of the origin position of the non-contact type position sensor 29 may be complicated. A calibration method of the sensor origin of such a three-dimensional shape measuring machine has been proposed by the present applicant in Japanese Patent Application No. 2004-357929.

  Furthermore, by placing a contact-type program on the personal computer 10 so that the input operation unit 11 can be operated together, the contact-type probe 39 is attached when particularly high-precision measurement is required. By switching the operation of the personal computer 10, it can also function as a contact-type three-dimensional shape measuring machine. A non-contact 3D shape measuring machine is configured by preparing a personal computer separately and importing the movement start position and movement end position data of the movement range, the detection signal of the linear scale, etc. from the original device. You can also. Further, as the non-contact type position sensor, a non-contact type three-dimensional shape measuring machine can be similarly configured by adopting a sensor for detecting the position of the surface range and moving the head accordingly.

It is a figure explaining the structure of the non-contact-type three-dimensional shape measuring machine by embodiment of this invention. It is a perspective view which shows the contact-type probe part which should be originally attached to the head of the non-contact-type three-dimensional shape measuring machine. It is a flowchart explaining operation | movement of the non-contact-type three-dimensional shape measuring machine.

Explanation of symbols

6 head 8 triaxial moving mechanism 9 vehicle body 10 personal computer 11 input operation unit 12 display unit 29 non-contact type position sensor 39 contact type probe

Claims (6)

A head to which a contact probe is attached, a three-axis movement mechanism that supports the head and moves in a horizontal direction, a vertical direction, and a direction perpendicular to these axes facing the measurement object, and a movement position of the three axes And a driving means for driving the three-axis movement mechanism to the commanded movement position so as to move and scan the head, respectively. A contact-type three-dimensional shape measuring machine adapted to measure the three-dimensional shape by sequentially detecting the three-dimensional position of the measurement object based on the detection signal of the moving position sensor is replaced with a predetermined probe instead of a contact type probe on the head. A non-contact type three-dimensional shape measuring method for diverting to measure a three-dimensional shape in a non-contact manner by attaching a non-contact type position sensor for detecting the position of a two-dimensional or three-dimensional detection range.
The origin calibration data of the origin position of the non-contact position sensor with respect to the origin position of the head is created in advance,
Sequentially instructing the movement start end position and movement end position of the movement range of the three-axis movement mechanism so as to drive-control the drive means;
In the moving scanning process of the head, a trigger command is given to the non-contact position sensor at a predetermined repetition cycle,
The origin position of the non-contact position sensor is obtained by calibrating the origin position of the head defined by the movement start end position, the movement end position, and the movement position for each repetition period in accordance with the origin calibration data. Then, the non-contact type three-dimensional shape measurement method is characterized in that the three-dimensional shape data of the measurement object is created from the non-contact detection position data of the non-contact type position sensor at the origin position. The moving position sensor of the contact type 3D shape measuring machine is an incremental linear scale,
The origin position of the non-contact type position sensor is the calibrated origin position defined by the commanded start end position and movement end position, and the count value for each repetition cycle from the movement start end position of the linear scale to the movement end position. The non-contact type three-dimensional shape measuring method according to claim 1, wherein   The head can be rotated and pitched with respect to a horizontal direction facing the measurement object and a horizontal axis perpendicular to the horizontal direction, and the origin position of the head and the origin position of the non-contact position sensor are respectively The non-contact type three-dimensional shape measuring method according to claim 1, wherein calibration is performed according to rolling and the pitching rotation angle.   4. The non-contact type three-dimensional sensor according to claim 1, wherein the non-contact type position sensor is a laser sensor that detects a distance in a predetermined two-dimensional range by means of fan-shaped scanning with laser light. Shape measurement method. A head to which a contact probe is attached, a three-axis movement mechanism that supports the head and moves in a horizontal direction, a vertical direction, and a direction perpendicular to these axes facing the measurement object, and a movement position of the three axes And a driving means for driving the three-axis movement mechanism to the commanded movement position so as to move and scan the head, respectively. A contact-type three-dimensional shape measuring machine adapted to measure the three-dimensional shape by sequentially detecting the three-dimensional position of the measurement object based on the detection signal of the moving position sensor is replaced with a predetermined probe instead of a contact type probe on the head. A non-contact type three-dimensional shape measuring device diverted to measure a three-dimensional shape in a non-contact manner by attaching a non-contact type position sensor for detecting the position of a two-dimensional or three-dimensional detection range,
Origin calibration data storage means for storing origin calibration data for calibrating the origin position of the non-contact type position sensor with respect to the origin position of the head, and the three-axis movement mechanism so as to drive and control the drive means A movement range command means for sequentially commanding a movement start end position and a movement end position of a movement range; and a detection command means for issuing a trigger command to the non-contact type position sensor at a predetermined repetition period during the movement scanning process of the head. Moving position data generating means for generating moving position data of three axes in the moving range in response to a detection signal of the moving position sensor for each repetition period, the moving start position data, the moving end position data, and The non-contact position sensor is obtained by calibrating the origin position data of the head defined by the movement position data corresponding to the origin calibration data. Shape data creating means for creating origin position data and creating three-dimensional shape data of the measurement object based on the non-contact detection position data of the non-contact position sensor for the origin position data. A non-contact 3D shape measuring device. The moving position sensor of the contact type 3D shape measuring machine is an incremental linear scale,
The shape data creating means includes the origin position data of the non-contact type position sensor, the calibrated origin position data defined by the commanded movement start position data and movement end position data, the movement start position and the movement end position. 6. The non-contact type three-dimensional shape measuring apparatus according to claim 5, wherein the non-contact type three-dimensional shape measuring apparatus is created with origin position data defined by movement position data which is a count value for each repetition cycle of the linear scale.

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