JPS61246605A - Measuring method for size of object - Google Patents

Abstract

PURPOSE:To conduct measurement with high accuracy without being affected by vibrations of an object of measurement, a measuring instrument and others, by finding a mean value of a plurality of measured values when the measurement is conducted by using two parallel beams of light. CONSTITUTION:Two parallel beams 10 of light are so applied that the respective parts Wa and Wb thereof are intercepted by the measured end portions 9a and 9b of an object 9 of measurement. Then, the areas Wa and Wb of the parallel beams 10 which are intercepted by the object 9 (or the area thereof not intercepted by the object) are detected, and thereby the size of the object 9 is measured. On the occasion, the measured end portions 9a and 9b of the object 9 are detected in the prescribed number of times respectively, and the size of the object 9 of measurement is calculated on the basis of a mean value of detected values. This method enables the reduction of an error in measurement owing to vibrations of the object 9 of measurement, a measuring instrument or the like, thus enabling the measurement of high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of measuring the dimensions of an object in a non-contact manner using light.

(Prior art) A conventional illumination device irradiates parallel light beams toward an object to be measured, and a detection means such as an optical sensor detects the parallel light beams that have passed through the edge of the object to be measured. Based on this detected value, the object is detected. A measuring method for calculating the dimensions of is known.

(Problem to be Solved by the Invention) However, in the conventional measurement method, the detection time is different for both ends of the object to be measured, so the object to be measured is In cases where minute vibrations are generated due to vibrations such as, etc., or when the measuring device used to measure the vibrations is vibrating, measurement errors occur.

FIG. 7 shows an example of this. For example, a rod-shaped member (109
), first, one end a of the measuring end is detected at an arbitrary time, and then the other end sb is detected after a certain period of time. However, this rod-shaped member (10111) is
``If the vibration is within the width between
- b", and when this end is detected between b and b', it is larger than the actual size, and conversely, when it is detected between b and b", it is detected at any position between b and b'. The measured value will be smaller than the actual size.

In order to solve this problem, a method of simultaneously detecting both ends of the measuring object may be considered, but it is subject to restrictions based on the size, shape, etc. of the object to be measured, and the measuring equipment etc. are expensive.

Therefore, the present invention has been made to improve the above-mentioned conventional problems, and its purpose is to provide a highly accurate, simple, and inexpensive method for measuring objects without being affected by vibrations of the object to be measured or the measuring device. To provide a method for measuring dimensions.

(Means and effects for solving the problems) In order to solve the above problems, the present invention provides two parallel rays (10) and (1).
0) is irradiated so that the respective parts Wa and Wb are blocked by the measurement ends (9a) and (8b) of the object to be measured (9). In a measurement method in which the dimensions of the object to be measured (8) are measured by detecting areas Wa, Wb (or areas not obstructed) by the object, the measurement end of the object to be measured (9) is (9a) and (lb) are detected a predetermined number of times (N times), and the measured object (8) is detected based on the average value of the detected values.
Since the dimensions are calculated, it is possible to reduce measurement errors due to vibrations of the object to be measured (9) or the measuring device.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a schematic diagram illustrating an embodiment of the present invention in the case of measuring the outer diameter dimension of a rod-shaped member.

The optical sensors indicated by symbols (1) and (1) are condensing lenses (2)
.

(2) and a transducer (4) that converts the optical signal into an electric signal such as a charge.
) and a transducer section (5).

On the other hand, the lighting devices indicated by symbols (8) and (11) are light sources (?)
, (7), and projecting lenses (8), (8) for irradiating light from the light sources (7), (?) as parallel rays, and these two optical sensors (1) , (1) and the illumination devices (6), (13) are arranged to face each other, and the parallel light beams (10), (10) from each illumination device (6) to the optical sensor (1) are arranged to face each other. The rod-shaped camshafts (9) are arranged in opposite directions and are arranged in parallel as much as possible, and are the object to be measured.
are lighting devices t (8), (8) and optical sensors (1), (1
) at a predetermined speed in a direction perpendicular to parallel rays (to) and (to).

The transformer 1 user (4), (4) is a semiconductor image sensor in which photodiodes or CCDs (charge coupled devices) are arranged in a straight line at a predetermined interval so as to be orthogonal to the parallel light beams (10), (1G). It consists of Each element (11)--is an arithmetic processing unit i (12)
The output signal is sequentially driven at fixed time intervals by timing pulses from a pulse generator (13) driven by a pulse generator (13), and its output signal is converted into a series by a parallel-to-serial converter (14), (14) and transmitted through a single signal line. Processing circuit (15), (15
) will be sent to.

The arithmetic processing unit (12) includes each processing circuit (15), (15
) The position of each measurement end (8a), (9b) of the camshaft (9) is calculated based on the output signal of the measurement end (9a).
, (9b). Here, the magnification and size of the optical image or the arrangement interval of the sensor elements (11)... and the optical sensor (11) in the plane perpendicular to the parallel light rays are calculated.
).

(1) Predetermined calculations are performed using known values such as the distance Wl between the two as necessary.

In the above, for example, the camshaft (8) is
), the detection signals at each measurement end (θa) and (9b) are as shown in FIG. 3B.

It vibrates as shown in (C). Therefore, Figure 3 or 4
As shown in the figure, each measurement end (9a), (9b) is detected a predetermined number of times (N times) at a period much shorter than this vibration period, and the detected values are averaged to eliminate errors due to the influence of vibration. If the dimensions of the camshaft (9) are calculated from the averaged detection values of the measured ends (9a) and (9b), highly accurate dimension measurements that are not affected by vibrations can be performed.

In addition, the detection of these measurement ends (9a) and (9b) is carried out by parallel light beams (10a) and (1) to optical sensors (la) and (1b).
0b), the re-measurement end of the camshaft (9a),
This is done by detecting the widths Wa and Wb of the portions shielded by Direction) Using Wl, find the outer diameter W of the camshaft (9)! is calculated as Wx=WI+Wa+Wb-t'. This measured value is outputted by an output device (1B) such as a CRT display or a printer, and if this value is abnormal, an alarm device (17) is activated.

In addition, values such as the optical system magnification and the spacing Wl between the sensors are determined by measuring a reference having known dimensions in advance, instead of the object to be measured.
It can be easily obtained by back calculating the result.

FIG. 5 is a graph showing the measurement results, and this graph (20) has the horizontal axis (21) as the moving speed (21a) of the camshaft (9), and the vertical axis (22) as the moving speed (21a) of the camshaft (9). (23
), (24) has amplitude (22a), ..., frequency (
23a), -1 and measurement error (24a), --- are shown, where symbols (25) and (2B) represent the longitudinal frequency and horizontal frequency of the camshaft (9), respectively, and symbols (27), ( 2B
) indicates the longitudinal amplitude and lateral amplitude of the camshaft (3), and symbol (29) indicates the measurement error.As is clear from the graph, the dimensional error in the outer diameter of the camshaft (9) is due to its external vibration, etc. Almost unaffected, approximately ±1fiL
This shows that according to the present invention, extremely highly accurate measurements can be performed.

As is clear from the above description, according to this embodiment, the same measurement is repeated a predetermined number of times at a period much shorter than the vibration period of the object to be measured or the measuring device, etc., and the dimensions to be obtained are calculated from the average value. This makes it possible to reduce measurement errors due to vibration, and also to reduce measurement errors due to sampling errors at the measurement end by an image sensor or the like, making it possible to perform highly accurate measurements.

Furthermore, the optical sensors (1), (1) and the illumination device (
8) and (8), when the object to be measured is small, the distance W between the light beams (1) and (1)! By making the distance W1 smaller and increasing the distance W1 when the object to be measured is large, it is possible to always detect only the positions of both ends (9a) and (9a) of the object (9), so it is possible to detect objects ranging from large to small. Optical sensor (1) whose outer diameter dimensions are always the same.

(1) and therefore the object to be measured (8)
The measurement accuracy (resolution) and processing time can be kept constant regardless of the size of the object, making it possible to perform dimension measurements that are highly reliable, easy, and inexpensive with excellent accuracy and processing time.

Although this example describes the measurement of the outer diameter of a rod-shaped camshaft, the present invention is not limited to this example, and can also be used to measure the length, shape, surface roughness, etc. of objects, for example. .

Further, in this embodiment, the camshaft (9) is connected to the optical sensor (1).
), (1) and the illumination devices (B), (8), but the measuring end of the object to be measured (8) (
13a), (9a) may be placed at any position as long as they face parallel light beams (10), (10), or the optical sensors (1), (1
) and the illumination devices M(8), (8) are also aligned in the direction of parallel light beams in the embodiment, but may be shifted in the same direction.

Furthermore, as shown in FIG. 6, a lighting device (30),
(3G) and an optical sensor (31
) and (31) may be arranged so that the directions of the parallel rays (32) and (32) are respectively the same.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, a simple and inexpensive method for measuring the dimensions of an object can be performed with high precision without being affected by vibrations of the object to be measured or the measuring device. method can be provided.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram illustrating an embodiment of the present invention in the case of measuring the outer diameter of a rod-shaped member, and Fig. 2 shows the vibration of the object to be measured and the detection signal of the optical sensor at this time. The diagram shown,
FIG. 3 and FIG. 4 are diagrams showing the measurement procedure, FIG. 5 is a diagram showing the measurement results, FIG. 6 is a diagram showing another embodiment, and FIG. 7 is a diagram showing conventional problems. In the drawings (1), (1)... optical sensors (6), (8)... lighting device (9)... object to be measured (9a), (9b)... measuring end ( 10), (I
Q)...Parallel rays (12)...Arithmetic processing device. Patent applicant Honda Motor Co., Ltd. Agent Patent attorney 2 1) Department patent attorney Kuni Ohashi Patent attorney Yuki Koyama Patent attorney No 1)
Mobian ('J ″' sect qko sect 3 fig 4

Claims (1)

[Claims] Two parallel rays are irradiated so that a portion of each is blocked by the measurement end of the object to be measured, and the area of each of the parallel rays that is blocked by the object to be measured (or the area that is not blocked) is In the measurement method, the measurement end portions of the object to be measured are detected by detecting the measurement end portions of the object to be measured, and the dimensions of the object to be measured are measured based on the detected values. 1. A method for measuring the dimensions of an object, characterized in that the dimensions of the object to be measured are calculated based on the average value of the detected values after detecting them a predetermined number of times.