JPS62179605A - Normal direction detecting sensor - Google Patents

Abstract

PURPOSE:To detect the direction of a normal with high accuracy, by making more than two receiving elements output a distance signal wit the size corresponding to the distance from a transmitting element while an arithmetic unit calculates the direction of normal to a surface to be measured of work. CONSTITUTION:A shaft 3 moves along the length of a copying plate 2, pressing the copying plate 2 against the surface of work 1 from the direction of the arrow (F). Variations in solid angle defined by the surface of the work 1 and the shaft 3 is absorbed as changes in contact angle between the shaft 3 and a universal joint 8 and moves following the shaft 3 along the surface of the work 1 while maintaining the same direction with the surface of the work 1. At this point, the relative position between a transmitting element 4 and three receiving elements 5a-5c changes the solid angle defined by the copying plate 2 and the shaft 3. This enables detection of the direction of a normal with high accuracy with a simple construction without being effected by the shape and material of work and the roughness of the surface to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a normal direction detection sensor that detects the normal direction of a measured surface of a workpiece having a three-dimensional free-form surface shape.

[Conventional technology]

Conventionally, a normal direction detection sensor for detecting the normal direction on the surface to be measured of a workpiece having a three-dimensional free-form surface shape is a combination of a light emitting element such as a light emitting diode and a plurality of light receiving elements such as photodiodes. There was something small. In the conventional normal direction detection sensor 4, a light emitting element irradiates the surface to be measured of the workpiece with light, a light receiving element detects the reflected light from the surface to be measured, and the degree of inclination of the surface to be measured is determined from the intensity of this reflected light. , that is, the normal direction is measured.

[Problems that Mitsukiri tries to solve]

Such conventional normal direction detection sensors are capable of highly accurate detection when the surface to be measured is smooth and has a high light reflectance.

However, if the surface roughness of the surface to be measured is large, the surface roughness varies greatly depending on the measurement position, or the reflectance of light is low on the surface to be measured, accurate measurement in the normal direction may be difficult. There was an IgJ title.

The present invention has been made to solve the above problems,
It is an object of the present invention to provide a normal direction detection sensor that can detect the normal direction of a surface to be measured of a workpiece with high accuracy regardless of the state of the surface to be measured of the workpiece.

[Means for solving problems]

Therefore, in the present invention, a copying plate contacts the surface to be measured of a workpiece having a three-dimensional shape at three points, and one end is attached to the back surface of the copying plate by a universal joint, regardless of the inclination of the copying plate.
A shaft that is always held in a fixed direction, a transmitting element that is attached to the approximate center of the shaft and outputs a predetermined signal, and a transmitting element that is attached to the back of the copying temporary and receives signals, and the distance from each transmitting element is determined. three or more receiving elements that output a distance signal of a size corresponding to the distance signal b:
Based on this, a normal direction detection sensor is constituted by an arithmetic unit that calculates the direction of the normal line on the surface to be measured of the workpiece.

[For production]

In the normal direction detection sensor configured as described above, the transmitting element outputs a predetermined signal, the receiving elements of 3 g or more each receive the signal of the transmitting element, and each receives a distance signal of a size corresponding to the distance from the transmitting element. Output. Further, the computing unit calculates the direction of the normal line on the measured surface of the workpiece based on the distance signal of the receiving element.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of a normal direction detection sensor according to the present invention. In Figure 1, (1) is a workpiece whose surface to be measured has a three-dimensional shape, (2) is a copying plate that contacts the surface to be measured of workpiece (1) at three points, and (3) is a copying plate with one end ( 2) by a universal joint (8), and the copying plate (2)
A shaft that is always held in a fixed direction regardless of the inclination of the
(4) is a transmitting element attached to a substantially central portion of the shaft (3). This transmitting element (4) is composed of a light emitting diode that emits light in the ultraviolet or infrared region. (5a), (5b), and (5c) are receiving elements attached to the upper outer periphery of the back surface of the copying plate at positions where they can receive light from the transmitting element (4).

The receiving elements (5a) to (5c) are composed of photodiodes, and each outputs a distance signal of a size corresponding to the distance from the transmitting element (4). In addition, the receiving element (5
It is assumed that a) to (5c) are placed at positions corresponding to the vertices of an equilateral triangle inscribed in a circle with radius r. (6)
is a computing unit that receives a distance signal via a signal line (7) and calculates the normal direction of the surface to be measured of the workpiece (1) in contact with the copying plate (2) based on this distance signal.

Next, the operation of the normal direction detection sensor according to the present invention will be explained. The shirt l-(3) moves in the length direction of the copying plate (2) while pressing the copying plate (2) against the surface of the workpiece (1) from the direction of arrow F shown in FIG.

The copying plate (2) measures the change in the solid angle created by the surface of the workpiece (1) and the shaft (3) by measuring the change in the solid angle between the shirt l-(31) and the universal joint (8).
), and moves along the surface of the workpiece (1) to follow the shirt I-(31) while maintaining the same direction as the surface of the workpiece (1).At this time, Transmitting element (4) and three receiving elements (5a) to (5C)
The relative position between the copying plate (2) and the shaft (1) changes depending on the solid angle formed by the copying plate (2) and the shaft (1).

FIG. 2 shows a two-dimensional coordinate representation of the transmitting element (4) and the receiving element (5) projected onto a plane parallel to the copying plate (2). As described above, each receiving element (5a) to (5c)
are located at each vertex of an equilateral triangle inscribed in a circle with radius r, and if the center of the circle is the origin (0,0), then the receiving element (5
The coordinates A, B, and C of a) to (5C) are A (0, r) B (,/”'3r/2p-r/2) C(,/'-3r/2.-r/2) Also, the seat of the transmitting element (4) +gM(X, Y
) are each receiving element (5a) to (5C) and transmitting element (4)
Letting the distances to these points be a, b, and c, respectively, then X=(b'-C2)/2(3r Y=(b2+c2-2 a'')/6r.

There, the C1 arithmetic unit (6) is connected to each receiving element (5a) to (5C
), the distances Na, b, and c are calculated from the output signal strength of the transmitter (4), and the position (x, y) of the transmitting element (4) is calculated. Furthermore, from the position (X, Y) of the transmitting element (4), the angle formed by the shirt I-(31) and the normal line of the copying plate (2), that is, the normal line direction is calculated.The normal line direction is displayed. You can do it like this.

Note that the transmitting element (4) and receiving element (
5a) to (5c) are the transmitting element (4) and each receiving element (
It is not limited to light emitting diodes and photodiodes, as long as it is possible to obtain a distance signal of a size corresponding to the distance from 5a) to 5c). Judging from the point of view of miniaturization and cost of the normal direction detection sensor, in addition to optical ones using a light emitting diode as the transmitting element (4) and photodiodes as the receiving elements (5a) to (5c), it is possible to use a light emitting element ( 4) Permanent magnet, receiving elements (5a) to (5C)
A magnetic type using a Hall element is preferable.

〔Effect of the invention〕

As explained above, according to the present invention, the inclination of the surface to be measured of the workpiece is taken out as the angle between the copying plate and the shaft, and
The normal direction of the surface to be measured of the workpiece is detected based on the two transmitting elements attached to the shaft and the receiving element attached to the copying plate, so the configuration is simple, and the shape, material, etc. of the workpiece can be easily detected. It is possible to obtain a normal direction detection sensor that can detect the normal direction with high accuracy without being affected by the surface roughness of the surface to be measured of the workpiece and its variations.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a normal direction detection sensor according to the present invention, and FIG. 2 is an explanatory diagram illustrating the detection principle of the normal direction detection sensor shown in FIG. 1. In each figure, 1 is a workpiece, 2 is a copying plate, 3 is a shaft, 4 is a transmitting element, 5 is a receiving element, 6 is a computing unit, 7 is a signal line, 8
is a universal joint. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (4)

[Claims] (1) A copying plate that contacts the surface to be measured of a workpiece having a three-dimensional shape at three points, and one end of which is attached to the back surface of the copying plate with a universal joint, so that the copying plate always moves in a fixed direction regardless of the inclination of the copying plate. A shaft to be held, a transmitting element attached to a substantially central portion of the shaft and outputting a predetermined signal, and a transmitting element attached to the back surface of the copying plate each receiving the signal, each of which has a distance from the transmitting element. , and an arithmetic unit that calculates the direction of a normal line on the surface to be measured of the workpiece based on the distance signal. Normal direction detection sensor. (2) The transmitting element is a light emitting diode that emits light in the ultraviolet region or infrared region, and the receiving element is a photodiode that detects the light from the light emitting diode.
Normal direction detection sensor described in section. (3) The normal direction detection sensor according to claim 1, wherein the transmitting element is a permanent magnet and the receiving element is a Hall element. (4) The normal direction detection sensor according to claim 1, wherein the three receiving elements are arranged at positions corresponding to respective vertices of an equilateral triangle inscribed in a circle with a predetermined radius.