JPH0445081B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a position detection device used for travel control of a transport moving device that moves along a fixed route, and in particular a position detection device that uses a reflective photoelectric sensor and a light reflecting surface. This relates to the position detection device used.

(Prior art and its problems) This type of position detection device is equipped with a reflective photoelectric sensor on one side of a moving device that moves along a fixed path and the path side, and a reflective photoelectric sensor on the other side. A light reflecting surface to be detected is provided parallel to the moving direction of the moving device. For example, a pair of the above-mentioned sensors are installed in parallel on the moving device side, and a light reflecting plate (light reflecting surface on the moving device side) is installed at the moving device stop position on the route side, which is slightly longer than the distance between the two sensors. The moving device may be configured to decelerate the moving device when a front sensor of the moving device detects the light reflecting plate, and to stop the moving device when both sensors simultaneously detect both ends of the light reflecting plate. Are known.

In the conventional position detection device used as described above, the sensor is attached to the moving device so that its optical axis is perpendicular to the moving direction of the moving device (perpendicular to the light reflecting plate). There is. Therefore, if there is an object that reflects light on the side of the moving device path that the sensor faces, there is a risk that the sensor will malfunction. For example, if the moving device route is covered by a tunnel-shaped metal plate duct, the light reflecting plate installed inside the duct and the inner surface of the duct will be relatively close to each other. Since the inner surface of the duct is parallel to the light reflecting plate, if the inner surface of the duct remains a metal plate surface, there will be a state in which the sensor is receiving reflected light from the inner surface of the duct and a state in which it is receiving reflected light from the light reflecting plate. The difference in output between the state of receiving reflected light and the state of receiving reflected light becomes very small, and the state of ON,
This not only makes it difficult to adjust the OFF switching level, but also increases the risk of malfunction. Of course, countermeasures such as painting the inner surface of the duct black can also be considered, but this increases the economic burden.

(Means and effects for solving the problems) The present invention proposes a position detection device capable of solving the above-mentioned conventional problems, and its characteristics are as follows: The optical axis is arranged so that it is not perpendicular to the moving direction of the moving device but is inclined at an appropriate angle, and the light reflecting surface is
The point is that detection by the sensor is enabled by diffused reflection of light rays.

In the above-mentioned device of the present invention, even if a metal plate duct is provided close to the light reflecting surface and parallel to the light reflecting surface as described above, the optical axis of the sensor is connected to the duct. Since it is inclined with respect to the inner surface, even if the projected light from the sensor is reflected by the smooth inner surface of the duct, it will not be received by the sensor. However, the light reflected from the sensor is diffusely reflected on the light reflecting surface, and at least a portion of the light is received by the sensor, so that a detection signal of the light reflecting surface can be obtained.

(Embodiment) An embodiment of the present invention will be described below based on the attached illustrative drawings.
is a transportation moving device that runs on the guide rail 2 by itself. Reference numeral 3 denotes a tunnel-shaped duct made of a metal plate that covers the transfer path of the moving device 1. Reference numeral 4 denotes a light reflecting plate, which is disposed within the duct 3 on the side of the moving path of the moving device 1 when the moving device 1 is at the stop position. This light reflecting plate 4
has a length that is parallel to the moving direction of the moving device 1 and approximately equal to the entire length of the moving device 1, and as shown in FIG. 5 is formed, for example, by pasting a light diffuse reflection tape such as the product name "Scotchi Tape" or by applying a light diffuse reflection paint (paint mixed with fine glass particles). Reference numerals 6 and 7 refer to a pair of front and rear reflective photoelectric sensors, which are moved so that the optical axes 6a and 7a of their projected light are not perpendicular to the moving direction of the moving device 1, but are symmetrically inclined toward the front and back outwards. It is installed horizontally near both front and rear ends of the device 1, and when the moving device 1 is located at the stop position, the optical axes 6a,
7a are both front and rear ends 5a, 5b of the light reflecting surface 5;
The interval between both sensors 6 and 7 is set so that they intersect with each other.

The sensors 6 and 7 have an optical axis 6a of their projected light.
Or, when 7a is at a position where it intersects with the light reflecting surface 5, the projected light from the sensor 6 or 7 is diffusely reflected on the light reflecting surface 5, and a part of it enters the light receiving part of the sensor 6 or 7 and is detected. Output occurs.
That is, the sensor 6 or 7 is switched from an OFF state to an ON state. However, as shown by the imaginary line in FIG. 3, when the projected light from the sensor 6 or 7 is reflected on the smooth inner surface of the duct 3, the reflected light is is reflected in a direction away from the sensors 6 and 7 and does not enter the light receiving portions of the sensors 6 and 7. That is,
Sensors 6 and 7 remain OFF.

To explain an example of how to use the pair of sensors 6 and 7, when the moving device 1 running on the guide rail 2 approaches the stop position, the front sensor 6 detects the light reflecting surface 5 and turns on. When the moving device 1 reaches the stop position, the traveling speed of the moving device 1 is automatically switched from high speed to low speed, and when the moving device 1 that has been decelerated reaches the stop position, both the front and rear sensors 6 and 7 detect the light reflecting surface 5 and are turned on. By controlling the mobile device 1 to forcibly stop when the
The moving device 1 can be automatically stopped at a predetermined position with high precision.

In addition, both sensors 6 and 7 have their optical axes 6a and 7a.
They can also be installed symmetrically inward so that they approach each other. Also, both sensors 6 and 7
When the moving device 1 is tilted symmetrically, the moving device 1 can be automatically stopped at the same position regardless of whether the moving device 1 is traveling forward or backward, but the traveling direction of the moving device 1 is limited to one direction. When you are there,
It is also possible to install both sensors 6 and 7 with parallel inclination in the same direction.

Furthermore, in the above embodiment, a sensor is attached to the moving device and a light reflecting surface is provided on the path side, but the arrangement can be reversed depending on how the sensor is used in the control system, or it can be used as a single sensor. It can also be implemented in combination with a light reflecting surface.

(Effects of the Invention) As described above, according to the position detection device of the present invention,
Even if the light-reflecting surface is placed close to an object that reflects light, such as a metal plate duct, the reflective photoelectric sensor must ensure that only the light-reflecting surface to be detected is detected. I can do it.
In other words, not only is it easier to adjust the ON/OFF switching level of the sensor, but also the reliability (stability) is improved. Further, there is no need to take measures such as painting the surface of the duct or the like facing the sensor black, which is economical.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional plan view, FIG. 2 is a longitudinal rear view, and FIG. 3 is an enlarged plan view of main parts. 1... Conveyance moving device, 2... Guide rail,
3... Metal plate duct, 4... Light reflecting plate, 5...
...Light reflecting surface, 6,7...Reflective photoelectric sensor,
6a, 7a... Optical axis of projected light.

Claims (1)

[Claims] 1. A reflective photoelectric sensor is attached to one of a moving device that moves along a fixed route and the route side, and a light reflecting surface that is detected by the sensor is provided on the other side in parallel to the moving direction of the moving device. In the position detection device, the reflective photoelectric sensor is disposed so that its optical axis is not perpendicular to the moving direction of the moving device but is inclined at an appropriate angle, and the light reflecting surface A position detection device that enables detection by the sensor.