JP2002347907A - Method and device for controlling moving rack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for controlling a moving rack in which the meander during the movement of a moving rack can be corrected. SOLUTION: The controlling method is to control each moving rack which involves skew and/or sideways dislocation during running by controlling the speed difference between the driving wheels installed on the left side and right side of the moving rack, whereby the left end and right end of a reflection mirror installed on any fixed object are irradiated and the reflected beams are sensed by a left and a right reflex type photoelectric tube installed on the moving rack, and if any of the photoelectric tubes does not sense the reflected light during running, the speed difference between the driving wheels is controlled so that both photoelectric tubes sense the reflected beams again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for controlling a moving shelf for preventing the moving shelf from skewing.

[0002]

2. Description of the Related Art In general, a moving shelf includes a frame 1 for storing articles as shown in FIGS. 4 and 5, a driving wheel 2 and a driven wheel 3 which are running wheels pivotally supported on left and right sides of the frame 1. ,
A wheel drive mechanism 4 such as a motor for rotating the drive wheel 2,
An engaging member of a guide roller 7 pivotally supported via a bracket 5 is provided, and a plurality of movable shelves 9 are arranged in parallel on a running path 8 having a total length L.

[0003] A guide rail 10 is provided on one side of the traveling path 8 and disposed horizontally.
Is fitted with the guide roller 7 of the movable shelf 9.

[0004] In the traveling path 8, the number of the moving shelves 9 is adjusted so as to form an interval S in which an article carrier such as a forklift can enter and exit the traveling path 8.

[0005] When articles are taken in and out of the moving shelf 9, the moving shelf 9 is sequentially moved by activating the wheel drive mechanism 4 of the moving shelf 9, and the end surface of the moving shelf 9 to be moved into and out of the moving shelf 9. A space S is formed between the moving shelf 9 and an end surface of another moving shelf 9 adjacent to the moving shelf 9.

As described above, since the movable shelf 9 is moved by the traveling wheels, the traveling path 8 does not need a protrusion or a groove such as a rail, and the article transporter can easily get into the gap.

However, there is a possibility that the moving shelf 9 may move obliquely with respect to the traveling path 8 due to idling of the traveling wheels or the like. In some cases, the angle becomes large, and the bracket 5 or the like pivotally supporting the guide roller 7 cannot move in contact with the guide rail 10.

Therefore, the moving shelf 12 shown in FIG.
3, a left and right wheel drive mechanism 16 such as a motor for rotating the left drive wheel 14, a left and right wheel drive mechanism 16 for rotating the right drive wheel 14, and the like. And a left rotation angle detector 17 such as a rotary encoder that detects the rotation speed of the left driven wheel 15 and a right rotation angle detector 17 such as a rotary encoder that detects the rotation speed of the right driven wheel 15. Have.

The left and right wheel drive mechanisms 16 and the left and right rotation angle detectors 17 provide a rotation angle detection signal 18 of the number of pulses from the left and right rotation angle detectors 17, that is, the left and right driven wheels 15.
The left and right wheel driving mechanisms 16 are connected to a movement controller 19 which is controlled based on the rotation speed of the vehicle.

When the moving shelf 12 moves in a predetermined direction on the basis of a movement command signal 20 from the outside, the movement controller 19 detects the rotation angle of the left rotation angle detector 17 per unit time by the left driven wheel 15. The rotation angle detection signal 18 and the right rotation angle detector 1 per unit time by the right driven wheel 15
7 is compared with the rotation angle detection signal 18 of FIG. 7, and if there is no difference between the left and right rotation angle detection signals 18, it is determined that the moving shelf 12 is operating normally, and if there is a difference between the left and right rotation angle detection signals 18. For example, it is determined that the movable shelf 12 is running abnormally, that is, is skewed.

For this reason, when the moving shelf 12 is skewed, the movement controller 19 controls the left wheel driving mechanism 16 or the right wheel driving mechanism 16 based on the rotation angle detection signal 18 per unit time. By controlling the rotation speed of the left driving wheel 14 and the right driving wheel 14,
To eliminate the skew.

[0012]

However, even if the movable shelf 12 shown in FIG. 6 is skewed due to the distortion of the traveling path of the traveling path 8, the moving shelf 12 per unit time of the right traveling wheel and the left traveling wheel can be used. If the number of rotations is the same, the movement controller 1
9 determines that there is no skew of the movable shelf 12, so that the skew of the movable shelf 12 cannot be reliably corrected.

In order to solve this problem, a position sensor is provided on the movable shelf 1, a plurality of reflectors are embedded at required intervals along the traveling path 8, and the reflector is detected by the position sensor to correct the trajectory. The disclosed technology has been disclosed (see JP-A-2001-48314).

By providing a position sensor and a reflector,
The guide rail 10 does not necessarily have to be provided, and an article transporter such as a forklift can easily enter and exit the gap S. However, since a large number of reflectors must be embedded in the floor, extra work and cost are required.

The present invention has been devised in view of the above-mentioned problems of the prior art, and uses a reflection type photoelectric device.
Provided is a control method and a control device for a movable shelf capable of detecting a skew or a lateral displacement of a movable shelf, thereby controlling a speed difference between left and right drive wheels, and thereby controlling the skew or a lateral displacement of the movable shelf. The purpose is to.

[0016]

SUMMARY OF THE INVENTION In order to achieve the above object, a method for controlling a moving shelf according to the present invention comprises controlling the speed difference between driving wheels provided on the left and right sides of the moving shelf to thereby control the speed of the moving shelf during traveling. A method of controlling a movable shelf for controlling skew and lateral displacement, which irradiates left and right ends of a reflecting mirror provided on a fixed object and reflects the reflected light with a pair of left and right reflective photoelectric tubes provided on the movable shelf. Controlling the speed difference between the driving wheels so that both the reflective phototubes detect the reflected light when either one of the left and right reflective phototubes does not detect the reflected light during traveling. It is.

The moving shelf control device of the present invention includes a moving control device for separately controlling the traveling speed of drive wheels provided on the left and right sides of the moving shelf, a reflecting mirror provided on a fixed object, and a moving shelf provided on the moving shelf. It consists of a pair of left and right reflective phototubes that irradiate the left and right ends of the reflective mirror and detect the reflected light, respectively, and one of the left and right reflective phototubes detects the reflected light while traveling on the moving shelf. If not, the signal is sent to the movement control device.

Next, the operation of the present invention will be described. When the movable shelf is moving correctly, the right reflective photoelectric tube provided on the movable shelf illuminates the right end of the reflective mirror provided on the fixed side, and the left reflective photoelectric tube illuminates the left end of the reflective mirror, respectively. The reflective phototube detects each reflected light. When the moving shelf begins to skew slightly to the right, the right reflective phototube no longer illuminates the right end of the reflective mirror, and thus the right reflective phototube no longer detects reflected light. The right reflective phototube sends the signal to the travel controller, which increases the speed of the right drive wheel or decreases the speed of the left drive wheel. Then, the movable shelf turns to the left, and both reflective phototubes detect the reflected light again, so that it is known that the movable shelf is oriented in the correct direction. Similarly, when the movable shelf shifts to the right or left, it can be detected and corrected.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of the moving shelf control device of the present invention. FIG. 2 is an enlarged plan view of the control device of the moving shelf. FIG. 3 is a flow sheet of the moving shelf control method according to the present invention. In these drawings, components common to those in FIGS. 4 to 6 are denoted by the same reference numerals, and redundant description will be omitted. In these figures, 21 is a reflection mirror provided on a fixed object. Note that the fixed object may be another moving shelf in a stationary state, or the original fixed object 27 may be used.
It may be. Reference numeral 22 denotes a pair of left and right reflective photoelectric tubes, and reference numeral 23 denotes light emitted from the reflective photoelectric tubes. Light 23
May be linear light as shown in FIG. 1 or slightly spread light as shown in FIG. When the light 23 is linear, it is desirable that the two lights are substantially parallel to each other. When the light 23 spreads slightly as shown in FIG. 2, it is desirable that the inner line 23a is substantially parallel or slightly narrowed forward. Reference numeral 24 denotes a movement control device, which is a speed command 20 from a control panel (not shown) and a signal 26 from a reflective photoelectric tube 22.
Upon receiving the command, a speed command 25 is transmitted to a wheel driving device 16 such as a motor connected to the left and right driving wheels 14.

Next, the operation of this embodiment will be described with reference to FIG. 1 and 2, the right-side reflection type photoelectric tube 22 is referred to as a sensor 1 and the left-side reflection type photoelectric tube 22 is referred to as a sensor 2. Further, the right driving wheel 14 toward the reflection mirror 21 is referred to as a wheel A, and the left driving wheel 14 is referred to as a wheel B. When both the sensor 1 and the sensor 2 are ON, the wheels A and B are traveling at the same speed. Note that ON means a state in which the light reflected by the reflection mirror 21 is received by the reflection-type photoelectric tube 22, and OFF.
This means that the light reflected by the reflection mirror 21 cannot be received by the reflection-type photoelectric tube 22. When the sensor 1 is turned off, the meandering correction is started, the speed of the wheel A is increased, and the speed of the wheel B is reduced. Note that only one of the speed increase and the deceleration may be performed. This state is completed in a short time, and the sensor 1
If is still OFF, the same is repeated. When the sensor 1 is turned ON, it is considered that the meandering correction has been completed, and the wheel A is decelerated, and the wheel B is accelerated to return to the original speed.

When the above control is overrun, the sensor 2 is turned off this time, so that the wheel A is decelerated and the wheel B is accelerated this time. Hereinafter, similar control is performed.
The reason why the meandering control is performed little by little by ON-OFF is to prevent hunting due to overrun.

As described above, in the present invention, the movement control of the movable shelf 12 can be reliably performed only by using the two reflection type photoelectric tubes 22 and the reflection mirror 21, so that the initial cost is low and the maintenance is easy. is there.

The present invention is not limited to the embodiment described above, and various changes can be made without departing from the gist of the present invention.

[0024]

As described above, the moving shelf control method and controller according to the present invention are excellent in that the skew and lateral displacement of the moving shelf can be reliably controlled using a low-cost and simple device. Has an effect.

[Brief description of the drawings]

FIG. 1 is a plan view of a control device for a moving shelf according to the present invention.

FIG. 2 is an enlarged plan view of FIG.

FIG. 3 is a flowchart illustrating a method of controlling a moving shelf;

FIG. 4 is a schematic perspective view of a conventional moving shelf.

FIG. 5 is an overall plan view of a conventional moving shelf.

FIG. 6 is a schematic perspective view of a conventional moving shelf control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Moving shelf 14 Drive wheel 21 Reflection mirror 22 Reflection type photoelectric tube 24 Movement control device 27 Fixed object

Claims (2)

[Claims] 1. A method of controlling a skew or a lateral shift of a control shelf during traveling by controlling a speed difference between drive wheels provided on both left and right sides of the movable shelf, the method being provided on a fixed object. The left and right ends of the reflecting mirror are illuminated, and the reflected light is detected by a pair of left and right reflective phototubes provided on the movable shelf, respectively, and one of the right and left reflective phototubes detects the reflected light during traveling. A moving shelf control method comprising: controlling the speed difference between the driving wheels so that both the reflective phototubes detect the reflected light again when not performed. 2. A moving control device for separately controlling the traveling speed of driving wheels provided on both left and right sides of the moving shelf, a reflecting mirror provided on a fixed object, and a left and right reflecting mirror provided on the moving shelf. It consists of a pair of left and right reflective phototubes that illuminate the end and detect the reflected light, respectively. When one of the left and right reflective phototubes does not detect the reflected light while traveling on the movable shelf, the signal is output. Of the moving shelf, which is adapted to send the data to the moving control device.