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EP-4115143-B1 - METHOD OF CONTACTLESS DETERMINATION OF GEOMETRIC ACCURACY OF THE SHAPE OF SPATIALLY CURVED AUTOMOTIVE GLASS IN A POSITION CORRESPONDING TO THE POSITION OF A GLASS MOUNTED ON THE CAR BODY AND A DEVICE FOR PERFORMING THE METHOD

EP4115143B1EP 4115143 B1EP4115143 B1EP 4115143B1EP-4115143-B1

Inventors

  • HORAK, Marcel
  • NOVOTNY, FRANTISEK
  • STARY, Michal
  • VRATNY, Jan
  • VRATNY, Miroslav

Dates

Publication Date
20260506
Application Date
20210303

Claims (15)

  1. A method of contactless determination of geometric accuracy of the shape of spatially curved automotive glass (6) in a car position, comprising the following steps - on the measurement surface (31) of the measuring table (3) in a horizontal position, at least three supports (4) for point contact with the measured automotive glass (6) are fixed/placed at measurement points, referred to as RPS points, determined by the glass or car manufacturer and at least three backstops (5) for defining the position of the measured automotive glass (6) are fixed/placed along the anticipated circumference of the measured automotive glass (6) at the points determined by the manufacturer, - the automotive glass (6) is placed on the supports (4) at RPS points and between the backstops (5) arranged on the measurement surface (31) of the measuring table (3), - the measuring table (3), together with a measuring head (12), rotates about the horizontal axis of rotation and stops as soon as the automotive glass (6) reaches the car position, - in a direction parallel to the axis of rotation of the measuring table (3), the measuring head (12) fitted with a number of non-contact measuring probes (11) directed towards the measurement surface (31) is moved over the surface of the automotive glass (6), while during the mutual movement of the measuring heads (11 ) and the measured automotive glass (6), the distance of the non-contact measuring probes (11) from the surface of the measured automotive glass (6) is evaluated in predetermined positions, which is compared with the required distance values in the positions corresponding to the measurement positions, wherein the distance between the contactless measuring probes (11) and the measurement surface (31) of the measuring table (3) is constant.
  2. The method according to claim 1, characterized in that in the car position the measured automotive glass (6) rests on all backstops (5) and all supports (4) arranged on the measurement surface (31).
  3. The method according to claim 1 or 2, characterized in that the measured values of the distances of the measuring probes (11) from the surface of the measured automotive glass (6) are compared with the values of the distances at the corresponding points of the CAD model of the respective automotive glass (6).
  4. The method according to any of the preceding claims, characterized in that the supports (4) and the backstops (5) are located on magnetic clamps (15), which are placed manually on the measurement surface (31) of the measuring table (3) in the direction of the x, y coordinates to a predetermined position of the measurement points, whereby the position is set by means of a laser beam perpendicular to the plane of the measurement surface (31) of the measuring table (3), whereby the heights of the supports (4) are adjusted individually according to the shape of the measured automotive glass (6) to the size of the z coordinate of the respective measurement point.
  5. The method according to any of claims 1 to 3, characterized in that the supports (4) and the backstops (5) are located on magnetic clamps (15), which are distributed on the measurement surface (31) of the measuring table (3) in the direction of the x, y coordinates by means of a distributor (13) to a predetermined position of the measurement points, whereby the heights of the supports (4) are adjusted individually according to the shape of the measured automotive glass (6) to the size of the z coordinate of the respective measurement point either before placing or after placing the supports (4) in the respective x, y coordinates.
  6. The method according to any of claims 1 to 3, characterized in that the supports (4) and backstops (5) are fixedly mounted at the measurement points on a plate of a pseudo-scale model (18) which is placed on the measuring table (3) on fixing mandrels (19) which define its position.
  7. The method according to any of the preceding claims, characterized in that the contactless measuring probes (11) are formed by confocal probes which emit beams of white light towards the surface of the measured product (6) and follow the beam reflected from the surface of the measured product (6) and evaluate the wavelength of the received beam from which they determine the distance from the surface of the measured product (6).
  8. The method according to any of claims 1 to 7, characterized in that the contactless measuring probes (11) are formed by ultrasound probes.
  9. A device for contactless determination of geometric accuracy of the shape of spatially curved automotive glass (6) in a car position, comprising a measuring table (3) and a frame (1) on which is rotatably mounted said measuring table (3) with a measurement surface (31) for placing the measured automotive glass (6), whereby the measuring table (3) is coupled to a drive (2) which belongs to said device and is also mounted on the frame (1) and is configured to be used to tilt the measuring table (3) with the measurement surface (31) and the measured automotive glass about a horizontal axis, whereby the measurement surface (31) is capable of occupying the horizontal position and the car position for the respective measured automotive glass (6), whereby the device further comprises linear guides (7), carriages (9) and a crossbar (8) configured such that on the edges of the measuring table (3), parallel to the horizontal axis of rotation of the measuring table (3), said linear guides (7) are placed on which said carriages (9) are mounted displaceably, which protrude above the measuring surface (31) and which are connected by said crossbar (8) in which a number of holes are created in defined positions and in which contactless measuring probes (11) are mounted, which together with the crossbar (8) form the measuring head (12), wherein the measured automotive glass (6) is positionable on at least three supports (4) arranged on the measurement surface (31) in the RPS points and its position around the circumference is defined by at least three backstops (5) arranged on the measurement surface (31) at points determined by the automotive glass or car manufacturer and in the car position, whereby the supports and backstops are part of the device and are configured such that the measured automotive glass (6) rests on all backstops (5) and on all supports (4) arranged on the measurement surface (31), whereby the contactless measuring probes (11) are connectedl/coupled to a control unit which is part of the device and is provided with evaluating means of the distance (z) of the contactless measuring probes (11) from the upper surface of the measured spatially curved automotive glass (6) in the respective coordinates (x, y) and means for comparing this distance with desired distance values at positions corresponding to the measurement positions.
  10. The device according to claim 9, whereby the contactless measuring probes (11) are arranged in the measuring head (12) in at least one row perpendicular to the direction of the relative movement of the measuring head (12) and the measuring table (3),
  11. The device according to any of claims 9 to 10, characterized in that the measuring head (12) is mounted displaceably in the measuring plane in the direction perpendicular to the direction of the relative movement of the measuring head (12) and the measuring table (3).
  12. The device according to any of claims 9 to 11, characterized in that the measuring head (12) is provided at the ends with tilting arms (10) in which also contactless measuring probes (11) are accommodated.
  13. The device according to any of claims 9 to 12, characterized in that the contactless measuring probes (11) are formed by confocal probes or ultrasound probes.
  14. The device according to any of claims 9 to 13, characterized in that the supports (4) and the backstops (5) are mounted on magnetic clamps (15) displaceably with respect to the measurement surface (31) and are adjustable in the determined position on the measurement surface (31) of the measuring table (3).
  15. The device according to any of claims 9 to 13, characterized in that the supports (4) and the backstops (5) are fixedly mounted at the measurement points on the plate of the pseudo-scale model (18) which can be fastened on the measurement surface (31) of the measuring table (3) by means of the fixing mandrels (19) which define its position.

Description

Technical field The invention relates to a method of contactless determination of geometric accuracy of the shape of spatially curved automotive glass in a car position. In addition, the invention relates to a device for contactless determination of geometric accuracy of the shape of spatially curved automotive glass in the car position, which comprises a frame on which is rotatably mounted a measuring table with a measurement surface for placing the measured automotive glass, the measuring table being coupled to a drive which is also mounted on the frame and which is used for tilting the measuring table with the measurement surface and the measured automotive glass about a horizontal axis. Background art At present, determination of the geometric accuracy of the shape of shaped glass, especially automotive glass, is performed in a contact manner on scale models, for example according to CN101749992, CN201926435, CN201964850, CN202216627 or CN208075720. A model equipped with several tens of contact sensors on the front side represents a partial 3D model of glass. The measured glass is placed on the model at RPS points and the position in the plane of the glass is determined by backstops. The glass is placed in the scale model on the RPS points between the backstops in an approximately horizontal position. The glass together with the scale model is then tilted by turning against the horizontal axis to a measurement position, the inclination of which to the horizontal plane corresponds to the position of the glass mounted on the car body (the so-called "car position"). The exact position of the glass is given by the glass resting on the backstops, to which it is pressed by gravity. At a single moment, all contact sensors are pushed into contact with the measured glass by a slight force, their position is recorded and compared with the coordinates corresponding to the 3D model. Coordinate differences must not exceed a predetermined value at the measured points. The disadvantage of measuring in a contact manner is the danger of glass deformation after its contact with the sensor and the resulting inaccuracy of the measurement. This is especially dangerous for very thin automotive glass currently produced. Another disadvantage is the need to have a unique scale model for each shape of glass. CN109084682 tries to solve this problem by contactless determination of geometric accuracy of the shape of products of glass, especially automotive glass, by means of two measuring sets with laser probes. The first measuring set comprises a point laser probe which can obtain coordinates of a certain point on the outer surface of automotive glass by scanning. The second measuring set comprises a line laser probe which can obtain coordinates of points of the black edge of automotive glass. When coordinates are obtained, they are compared with a standard sample. The disadvantage of using laser sensors (point and line laser sensors) for shape rugged surfaces is the inaccuracy of triangulation position measurement with a variable dependence of the measured value on the deviation of the transmitted beam from the measured surface normal. This disadvantage is even more pronounced for the case of sensing a glossy surface with a high degree of parasitic reflections. Another drawback is a reduced robustness of the sensor, associated with a high sensitivity to fluctuations in the exposure parameters of the sensed scene. WO2013034812A1 describes a device for measuring the flatness of a reflecting surface, such as the surface of glass, by measuring a distance from the reflecting surface, which comprises two light sources that emit light beams in such a manner that these beams are incident on the reflecting area common to both beams. The device is capable of measuring the flatness of a flat glass in the horizontal and vertical positions of the reflecting surface. JP2008139268 discloses a device for measuring fine shape deviations in glass substrates, especially for flat displays. The device comprises a table for placing the element to be measured and a plurality of air scanners. The table is coupled to a drive which ensures its movement under the system of air scanners, wherein longitudinal movement of the table is part of the background art. WO2005022127A2 describes a support for a plurality of conformably arranged spaced-apart distance-measuring sensors for measuring the distance to a curved glass sheet in the automotive industry (e.g. a windshield). The device comprises a reference base plate and a plurality of spaced apart sensors disposed thereon, the sensors being more densely arranged at points of curvature of the element to be measured. The device uses optical sensors comprising an emitter and optical elements to send light to the element to be measured and other optical elements to direct the reflected light to a light receiver, such as a CCD line element. The object of the invention is therefore to eliminate the above-mentioned d