JPH07260442A - Method and apparatus for measuring profile of tubular body - Google Patents

Abstract

PURPOSE:To realize highly accurate measurement of profile by shifting a measuring head equipped with laser displacement gauges in accordance to a design profile preset in a robot and irradiating the surface of a tubular body vertically with a laser beam while keeping the outer periphery of the tubular body within the range of the displacement gauges. CONSTITUTION:A tubular body W is mounted on a surface plate 3 which is the elevated by means of a cylinder and set at a predetermined height. A robot 5 is disposed on the side of a measuring position and a measuring head 6 is fixed to the forward end of the arm thereof. The measuring head 6 is equipped with laser displacement gauges 7 in three stages in order to measure the profile of the tubular body W simultaneously at three heights. Since the laser displacement gauge 7 has limited range of high accuracy measurement, the design profile of the tubular body W is preset in the robot 5 and the arm thereof is rotated or telescoped to shift the measuring head 6 according to the design profile thus keeping the tubular body W within a range. Furthermore, the head 6 is rotated at the forward end of the arm and the surface of the tubular body W is irradiated vertically with a laser beam thus measuring the profile accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring the outer shape of a tubular body such as a honeycomb structure.

[0002]

2. Description of the Related Art Since a honeycomb structure used as a catalyst carrier for purifying exhaust gas of an automobile is a ceramic product, it is inevitable that the honeycomb structure is slightly deformed from its designed shape due to shrinkage during firing. For this reason, it is necessary to accurately measure the outer shape, but when using a contact-type measuring device, the thin surface may be chipped, so it is preferable to use a non-contact-type measuring device.

Conventionally, for this purpose, there is a contour measuring method for irradiating an end face of a rotating honeycomb structure placed on a turntable with parallel light rays and measuring a change in a position where the light rays are blocked by a light receiver. Developed, JP-A 64-759
It is known from the 04 publication. However, this method has a problem that the outer shape cannot be accurately measured for a honeycomb structure having a concave portion to which a light ray does not reach depending on an angle.

Therefore, the present inventors are developing a method for measuring the outer shape of a tubular body such as a honeycomb structure using a commercially available laser displacement meter, and it is suspended from a rotary disk 21 as shown in FIG. A laser displacement meter 23 is attached to the arm 22 and the rotating disk 21 is placed on a surface plate 24, and a cylindrical body W such as a honeycomb structure is formed.
A technique for measuring the outer shape of the cylindrical body W by rotating the laser displacement meter 23 in a circular orbit around the outer circumference of the cylindrical body W by rotating the laser displacement meter 23 above was developed. However, this method is practical when the cylindrical body W is a cylindrical body and can perform accurate measurement, but as shown in FIG. 6, if the outer shape and size of the cylindrical body W are made versatile. It was found that the measurement accuracy was reduced.

The first reason is that if a laser displacement meter 23 having a wide measurement range that can cope with changes in the outer shape and size of the cylindrical body W is used, the measurement accuracy of the laser displacement meter 23 becomes poor. Because it will be. The second reason is that the laser displacement meter 23 obtains high measurement accuracy when the laser is irradiated perpendicularly to the surface of the object to be measured, but the laser displacement meter 23 is rotated in a circular orbit. Then the laser displacement meter 23 always faces the center of rotation,
This is because, depending on the shape of the tubular body W, it becomes impossible to irradiate the laser perpendicularly to the surface thereof.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above problems and has a versatility in the shape and size of the tubular body W,
In addition, the present invention has been made to provide a method and apparatus for measuring the outer shape of a cylindrical body, which can always accurately measure the outer shape with a highly accurate laser displacement meter.

[0007]

In order to solve the above-mentioned problems, a method for measuring the outer shape of a cylindrical body according to the present invention comprises a measuring head equipped with a laser displacement meter, the design shape of the cylindrical body being set in advance. It is characterized in that the outer shape of the tubular body is measured while the robot is moved while keeping a substantially constant distance from the outer peripheral surface of the tubular body. Further, the tubular outer shape measuring device of the present invention comprises a surface plate on which a cylindrical body which is an object to be measured is placed, and a laser displacement meter which is arranged on the side of the surface plate and attached to the tip of an arm. And a robot for moving the measuring head according to a preset design shape while keeping a substantially constant distance from the outer peripheral surface of the cylindrical body.

[0008]

According to the present invention, the measuring head equipped with the laser displacement gauge is moved according to the design shape preset in the robot, so that the measuring head is moved at a substantially constant distance from the outer peripheral surface of the cylindrical body. While measuring the distance to the outer peripheral surface of the tubular body. For this reason, the outer peripheral surface of the tubular body can always be kept within the measurement range of the laser displacement meter, which enables highly accurate measurement. Further, the robot can change the angle of the measuring head to irradiate the laser always perpendicularly to the surface of the cylindrical body. Generally, in a laser displacement meter, if the laser irradiation direction is not perpendicular to the measurement surface and the angle between them becomes small, the accuracy deteriorates. A robot can be used to position the laser displacement gauge so that the laser irradiation direction is always perpendicular to the measurement surface. For these reasons, according to the present invention, it is possible to accurately measure the outer shape of a tubular body having various cross-sectional shapes.

[0009]

The present invention will be described below in more detail with reference to the illustrated embodiments. In FIG. 1, 1 is a machine base, 2 is a rail provided on the machine base, and 3 is a surface plate which runs on the rail 2 by a uniaxial robot (not shown). A mark indicating the outer peripheral shape of the tubular body W is provided on the surface plate in order to set the tubular body W at a predetermined position. However, the setting of the tubular body W for the mark does not necessarily require a high degree of accuracy. At the position shown by the imaginary line in FIG. 1, the tubular body W is placed on the surface plate 3 and travels together with the surface plate 3 to the measurement position shown by the solid line. A cylinder 4 for pushing up the surface plate 3 while keeping the surface plate 3 horizontal is provided at the measurement position, and the cylindrical body W is placed at a predetermined height together with the surface plate 3.

A robot 5 is installed on the side of this measurement position. As shown in FIG.
A measuring head 6 as shown enlarged in FIG. The measuring head 6 of the embodiment is provided with laser displacement gauges 7 in upper and lower three stages, and the outer shape of the cylindrical body W can be simultaneously measured at three heights. 7 may be one.

As described above, the laser displacement meter 7 has a relatively narrow measurement range in which high precision measurement is possible. In the present invention, however, the robot 5 has the designed shape of the cylindrical body W to be measured.
The robot 5 as shown in FIGS. 3 and 4.
The measuring head 6 is moved in accordance with the set design shape by rotating and expanding / contracting the arm. At the same time, the measuring head 6 itself is rotated by the tip of the arm of the robot 5. As a result, the laser displacement meter 7 is
The laser beam moves while being kept at a substantially constant distance from the outer peripheral surface of the cylindrical body W, and the laser beam is always irradiated perpendicularly to the outer peripheral surface of the cylindrical body W.

At this time, since the laser displacement meter 7 can always capture the outer peripheral surface of the cylindrical body W within its measurement range, the distance to the outer peripheral surface of the cylindrical body W can be measured with high accuracy. . Further, since the coordinates of the laser displacement meter 7 itself during movement can be accurately grasped based on the data set in the robot 5, when the sectional shape of the cylindrical body W is not only a circle but also a multi-arc assembly, Also, the outer shape of the tubular body W can be accurately measured. In particular, if a plurality of laser displacement gauges 7 are provided in the measuring head 6 as in the embodiment, the outer shape of the tubular body W at a plurality of heights can be measured at the same time.

The measuring head 6 of the embodiment is provided with a linear gauge 8 for height measurement. The height measuring linear gauge 8 rotates the measuring head 6 after the measurement by the laser displacement meter 7 is finished, and the lower end of the height measuring linear gauge 8 is brought into contact with the upper surface of the cylindrical body W to make the cylindrical body W It is for measuring the height of the, but is not essential in the present invention. When the measurement of one cylindrical body W is completed in this way, the surface plate 3 is lowered and returned to the take-out position by the uniaxial robot.

[0014]

As described above, according to the method and apparatus for measuring the outer shape of the cylindrical body of the present invention, the measuring head is substantially constant from the outer peripheral surface of the cylindrical body according to the preset design shape by the robot. Since the outer shape of the tubular body is measured while moving the tubular body W while maintaining the distance, there is an advantage that the outer shape of the tubular body W can always be accurately measured even when the shape of the tubular body W deviates greatly from the cylindrical shape. is there. Therefore, the present invention is suitable for measuring the outer shape of a tubular body such as a honeycomb structure.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the measuring head of the embodiment.

FIG. 3 is a side view showing a measurement state.

FIG. 4 is a plan view showing a measurement state.

FIG. 5 is a side view showing a disc type measuring device.

FIG. 6 is a plan view showing a change in distance between the laser displacement meter and the outer peripheral surface of the cylindrical body W in the disc type measuring device.

[Explanation of symbols]

3 surface plate, 5 robots, 6 measuring heads, 7 laser displacement meter, W cylindrical body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Matsuoka 2-56 Sudacho, Mizuho-ku, Aichi Prefecture Nagoya City

Claims (3)

[Claims] 1. A measuring head equipped with a laser displacement gauge is moved by a robot having a design shape of a tubular body set in advance while keeping a substantially constant distance from the outer peripheral surface of the tubular body,
A method for measuring the outer shape of a tubular body, which comprises measuring the outer shape of the tubular body. 2. The method for measuring the outer shape of a cylindrical body according to claim 1, wherein the laser irradiation direction is substantially perpendicular to the measurement surface. 3. A surface plate on which a tubular body, which is an object to be measured, is placed, and a measuring head provided with a laser displacement meter, which is arranged on the side of the surface plate and is attached to the tip of an arm, is preset. An outer shape measuring device for a tubular body, comprising: a robot that moves according to a design shape while keeping a substantially constant distance from the outer peripheral surface of the tubular body.