JP2679236B2 - Non-contact type shape measuring device - Google Patents

Description

The present invention relates to an apparatus for measuring the shape of an object to be measured without contacting the surface to be measured.

[Conventional technology]

Conventionally, in measuring the shape of an object to be measured such as a press-molded product or a resin mold, a contact-type shape measuring device in which a measuring needle is brought into direct contact with the surface to be measured and the position is read is widely used. This device has a disadvantage that the measuring needle is worn. Therefore, in recent years, a non-contact type shape measuring device has been developed, and as one of them, a device using a triangulation method has been proposed.

This device will be described with reference to FIG. In the figure,
Reference numeral 80 is an optical sensor having light emitting and light receiving means, and the light receiving means has a light receiving area that extends in the W axis direction in the drawing. The optical sensor 80 irradiates the surface S to be measured with the irradiation light A, and the reflected light B is received by the light receiving means.
The distance from the surface S to be measured is calculated from the light receiving position (light receiving position in the W axis direction).

[Problems to be solved by the invention]

However, as shown in the figure, when the surface S to be measured is curved inward with a large curvature, not only the regular reflected light B incident at the shortest distance from the measurement point P but also other points at other points. Up to the reflected light B ', which is subsequently reflected, may be incident on the light receiving means, which hinders accurate measurement. Further, as shown in FIG. 9, when the inclination angle of the surface S to be measured with respect to the optical axis of the irradiation light A is large, the object to be measured itself becomes an obstacle to weaken the reflected light, or the light is completely shielded and received. Without reaching the means,
It may become impossible to measure.

Therefore, it is an object of the present invention to solve the problem caused by the shape of the surface to be measured and to provide a non-contact type shape measuring apparatus capable of performing accurate measurement.

[Means for solving the problem]

The present invention comprises an optical sensor having a light emitting means and a light receiving means, irradiating light to a measurement point on a surface to be measured by the light emitting means, and receiving the reflected light from the light reception output of the light receiving means to measure the object to be measured. In a non-contact type shape measuring device for measuring a shape, a support means for supporting the optical sensor so as to be rotatable around the optical axis of the light emitted by the light emitting means, and a measurement for the optical axis from the shape data already measured. Calculating means for calculating the inclination of the surface to be measured at a point, and the optical sensor is driven to rotate based on the result of the calculation, and the light emitting means and the light receiving means form a plane including the optical axis and the normal vector of the surface to be measured. And a setting means for setting them so as to be aligned in a direction substantially orthogonal to each other.

(Operation)

According to the above configuration, the light emitting means and the light receiving means of the optical sensor are arranged on the plane including the optical axis of the irradiation light and the normal vector of the measured surface based on the inclination of the measured surface calculated based on the already calculated data. Since the optical sensors are driven to rotate so as to be arranged in the direction orthogonal to each other, the light emitted from the light emitting means and reflected on the surface to be measured is reliably incident on the light receiving means with a short width.

Further, according to the method of comparing the inclination of the measured surface with a preset inclination, the optical sensor is driven to rotate only when the inclination of the measured surface with respect to the optical axis exceeds a predetermined reference. .

〔Example〕

FIG. 2 shows the overall configuration of the shape measuring apparatus in one embodiment of the present invention.

In the figure, reference numeral 20 is an arch, and an object transfer device 22 is installed below the arch 20. The object transfer device 22 includes an X-axis slide member 241, a Y-axis slide member 242, and a Z-axis slide member 243 that are slidable in the X-, Y-, and Z-axis directions. , X
Axis drive motor 261, Y-axis drive motor 262, Z-axis drive motor
263 (see FIG. 4 described below) and a ball screw 27 connected to the drive shaft of each motor are slidably driven.

A table 28 on which an object to be measured is placed is fixed to the upper portion of the Z-axis slide member 243, and an optical sensor 30 is provided above the table 28. This light sensor 30
A sensor swivel drive motor 32 fixed to the upper part of 20 is connected via a speed reducer and a swivel shaft 31 (not shown).
It is possible to turn around (around the Z axis).

As shown in FIG. 3, a semiconductor laser (light emitting means) 36 and a position reading sensor (light receiving means) 37 are provided in a housing 34 of the optical sensor 30, and an inclined wall 341 formed in a lower portion of the housing 34 is provided. The condenser lens 38 is fixed. The semiconductor laser 36 is arranged at a position where the optical axis of the irradiation light A coincides with the turning axis 31, and the position reading sensor 37 spreads in the W axis direction having a predetermined angle with respect to the Z axis. It has a light receiving area. This optical sensor 30
Is the irradiation light A on the surface S to be measured by the semiconductor laser 36.
The position reading sensor 37 receives the reflected light B through the condenser lens 38, and reads the light receiving position (specifically, the light receiving position in the W-axis direction).

FIG. 4 shows an arithmetic and control unit 40 provided in this shape measuring apparatus. The position detection sensor 37 and the detection signals of the length measuring devices 421 to 423 for measuring the transfer distance of the measured object in each axial direction are input to the arithmetic and control unit 40. A control signal is output to the device 44, the data recording device 46, the sensor rotation drive motor 32, and the drive motors 261 to 263 for the X, Y, and Z axes. , The calculation means 12, the control means 14, and the comparison means 16 shown in FIG.
It has the function corresponding to each. The above display device
Reference numeral 44 indicates the measured shape data, and the data recording device 46 records the calculated data on the magnetic disk.

 Next, the shape measuring operation performed by this apparatus will be described.

First, with the object to be measured placed on the table 28,
The Z-axis slide member 243 is driven up and down to a position where the measurement of the measured object is possible. Normally, the height of the table 28 is fixed at this stage, but when the undulation of the surface S to be measured of the object to be measured is large, the Z-axis slide member is controlled even during measurement under the control of the arithmetic and control unit 40. 28 is appropriately driven so that the object to be measured is always kept at a measurable height position.

At this position, as shown in FIG. 3, the irradiation light A is emitted from the semiconductor laser 36 in the optical sensor 30 onto the surface S to be measured. The irradiation light A is reflected by the surface S to be measured, passes through a condenser lens 38, and is received by a position reading sensor 37. A signal relating to the light receiving position (light receiving position in the W-axis direction) is given to the arithmetic and control unit 40. Entered in. Arithmetic control device 40
Calculates the distance from the semiconductor laser 36 to the measuring point P based on this information signal, and outputs the data to the display device 44 and the data recording device 46.

On the other hand, the X-axis drive motor 261 and the Y-axis drive motor 262 are appropriately operated by the control signal of the arithmetic and control unit 40, whereby the X-axis slide member 241 and the Y-axis slide member 242 are driven in the respective axial directions, and the optical sensor The object to be measured is transferred relative to 30. As a result, the main scanning and the sub-scanning of the optical sensor 30 with respect to the object to be measured are performed, and by performing such scanning and the measuring operation in parallel, the height position of each point on the surface to be measured S is measured. Are sequentially read,
As a result, the overall shape is measured.

Furthermore, in this device, the orientation of the optical sensor 30 is adjusted at each measurement point by outputting a control signal from the arithmetic and control unit 40 to the sensor turning drive motor 32. Next, the specific control content will be described.

In FIG. 5, reference numeral 51 denotes an unmeasured area that has not yet been measured on the surface to be measured (a plain area in the figure), and 52 denotes a measured area that has already been measured (a shaded area in the figure).
The distance data calculated in the area (mesh area in the figure) 53 in the vicinity of the current measurement point P among the previously measured areas 52 is extracted, and the measured surface S at the measurement point P is extracted based on these data.
Calculate the slope of. In this device, data on nine existing measurement points near the measurement point P are extracted, and based on these data, the tangent plane at the measurement point P of the measured surface S as shown in FIG. The slope of Q is calculated. In this embodiment, a normal vector η at the measurement point P on the tangent plane Q as shown in FIG. 7 is calculated as the inclination.

The arithmetic and control unit 40 calculates an angle φ formed by the normal vector η and the optical axis of the irradiation light A, and compares this angle φ with a preset setting angle (10 ° in this embodiment). When the angle φ is less than or equal to the set angle, the optical sensor 30 is not rotated, but when the angle φ is greater than the set angle, the intersection line (that is, the contour line) L between the tangent plane Q and the XY plane is obtained and The angle θ formed by the line of intersection L and the X axis is obtained, and the optical sensor 30 is turned so that the semiconductor laser 36 and the position reading sensor 37 are aligned in the same direction as the line of intersection L.

According to such a device, when the surface S to be measured is tilted by a certain amount or more with respect to the optical axis of the irradiation light A, a direction orthogonal to a plane including its normal vector η and the optical axis of the irradiation light A, That is, since the optical sensor 30 is driven to rotate so that the semiconductor laser 36 and the position reading sensor 37 are aligned in the direction of the contour line of the surface S to be measured, the surface S to be measured of the surface S to be measured as shown in FIGS. The undulation does not affect the reflected light B, and good measurement can always be performed at each measurement point.

Further, as described above, the optical sensor 30 is rotated only when the angle φ formed by the normal vector η and the optical axis is a certain value or more, that is, when the shape of the surface S to be measured affects the measurement accuracy. By doing so, the time required for turning the optical sensor 30 can be minimized, and the measurement efficiency can be improved.

It should be noted that the present invention is not limited to this embodiment, and the following aspects can be taken as an example.

(1) In the present invention, it suffices that the optical axis of the irradiation light and the turning axis of the optical sensor match, and the specific directions of both axes do not matter. For example, when light is applied to the surface to be measured in the X-axis direction, the turning axis of the optical sensor may be set in the same direction.

(2) In the present invention, the direction of the optical sensor does not have to be exactly the same as the direction orthogonal to the plane including the optical axis and the normal vector, and there is a slight difference between the two in a range that does not affect the measurement accuracy. There may be a difference. Further, it is not necessary to actually calculate the normal vector, and as a result, the object of the present invention can be achieved by controlling so that the optical sensor faces the above direction.

(3) The present invention can be applied to a measuring device in which the measurement accuracy changes when the direction of the sensor is changed with respect to the shape of the object to be measured, regardless of the types of the light emitting means and the light receiving means.

〔The invention's effect〕

As described above, the present invention calculates the inclination of the surface to be measured with respect to the optical axis of the irradiation light from the data already detected by the optical sensor, and the light emitting means and the light receiving means of the optical sensor include the optical axis and the surface to be measured. Since the optical sensors are rotated around the optical axis so that they are aligned in a direction substantially orthogonal to the plane including the normal vector, the shape of the surface to be measured can be controlled by a simple mechanism and control. Therefore, it is possible to always read the light receiving position of the reflected light with high accuracy.

Furthermore, by comparing the angle formed by the normal vector of the surface to be measured and the optical axis with a preset angle, and turning the optical sensor only when the former exceeds the latter, the optical sensor There is an effect that the measurement efficiency can be improved by minimizing the time for turning.

[Brief description of the drawings]

FIG. 1 is a functional configuration diagram of a main part of a non-contact type shape measuring device of the present invention, FIG. 2 is an overall configuration diagram of a non-contact type shape measuring device in an embodiment of the present invention, and FIG. FIG. 4 is an internal structure diagram of an optical sensor provided, FIG. 4 is a hardware configuration diagram of an arithmetic control device and the like provided in the device, FIG. 5 is an explanatory diagram showing an unmeasured region and an already measured region on a surface to be measured, FIG. 6 is a perspective view showing a tangent plane at a measurement point on the surface to be measured, FIG.
The figure is a perspective view showing the tangent plane and a normal vector of the tangent plane, and FIGS. 8 and 9 are explanatory views showing the relationship between the shape of the surface to be measured and the reflected light incident on the optical sensor. 10 ... Driving means, 12 ... Computing means, 14 ... Control means, 16
...... Comparison means, 30 ...... Optical sensor, 32 ...... Sensor rotation drive motor (driving means), 36 …… Semiconductor laser (light emitting means), 37 …… Position reading sensor (light receiving means), 40 …… Computational control device (Arithmetic means, control means, and comparison means),
A: irradiation light, B: reflected light, P: measurement point, S: surface to be measured, η: normal vector, φ: angle between normal vector and optical axis.

Claims (4)

(57) [Claims] 1. An object to be measured is provided with an optical sensor having a light emitting means and a light receiving means, the light emitting means irradiates a measuring point on a surface to be measured with light, and the light receiving output of the light receiving means receives the reflected light. In the non-contact type shape measuring device for measuring the shape of, the supporting means for supporting the optical sensor so as to be rotatable around the optical axis of the irradiation light by the light emitting means, and the shape data already measured, with respect to the optical axis Computation means for calculating the inclination of the surface to be measured at the measurement point, and the optical sensor is driven to rotate based on the result of the computation, and the light emitting means and the light receiving means are planes including the optical axis and the normal vector of the surface to be measured. A non-contact type shape measuring device, comprising: a setting unit configured to be arranged in a direction substantially orthogonal to the above. 2. The non-contact type shape measuring apparatus according to claim 1, further comprising drive means for driving the optical sensor to rotate about the optical axis, wherein the setting means is based on a calculation result of the calculation means. A non-contact type shape measuring device comprising a control means for controlling the driving means so that the light emitting means and the light receiving means are arranged in the above direction. 3. The non-contact type shape measuring device according to claim 1, further comprising a distance measuring means for sequentially measuring distance data between a measuring point on a surface to be measured and an optical sensor from a light receiving output of the light receiving means. A non-contact type shape measuring device, characterized in that the shape of an object to be measured is measured based on sequentially measured distance data. 4. The non-contact type shape measuring apparatus according to claim 1, further comprising a comparing means for comparing the inclination of the surface to be measured calculated by the calculating means with a preset inclination, wherein the setting means is the former. A non-contact type shape measuring device characterized in that the optical sensor is driven to rotate only when is larger than the latter.