JP2788524B2 - Obstacle detection device for unmanned forklift - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an obstacle detection device for an unmanned forklift, and more particularly, to an unmanned forklift for loading or unloading a shelf. The present invention relates to an obstacle detection device that instructs an unmanned forklift to stop running when an obstacle exists during the period.

(Prior Art) Conventional unmanned forklifts are generally configured to detect a forward obstacle by a sensor attached to the tip of a fork.

(Problems to be Solved by the Invention) Therefore, in the conventional unmanned forklift, it was not possible to detect an obstacle existing between the forklift and the shelf.
That is, when carrying out unloading or loading work on the shelf, the forklift advances toward the shelf with at least the fork raised to a position higher than the upper surface of the shelf, and at this time, there is an obstacle in front of the shelf. Even if it is, the sensor at the tip of the fork can not detect this,
Therefore, there is a problem that an obstacle is sandwiched between the vehicle body and the shelf.

In view of the above problems, the present invention has been made in view of the above-described problems, and when an unmanned forklift is loading or unloading a shelf, if there is an obstacle in front of the shelf, the obstacle can be detected and the unmanned forklift can be stopped. An object is to provide an object detection device.

(Means for Solving the Problems) The present invention is configured as follows to solve the above problems.

That is, the obstacle detection device according to the present invention includes a mark plate installed on the floor at a predetermined distance from the shelf, and a mark plate provided on an unmanned forklift for detecting the mark plate and outputting a detection signal. A detection sensor, an obstacle detection sensor that detects the presence or absence of an obstacle between the unmanned forklift and the shelf and outputs a detection signal thereof, and when both signals of the mark plate detection sensor and the obstacle detection sensor are received. And a travel control circuit for stopping the unmanned forklift.

(Operation) According to the obstacle detection device of the present invention configured as described above, the unmanned forklift advances toward the shelf in order to perform a loading operation or a loading operation on the shelf, and the mark plate detection sensor detects the position of the shelf. When the detection signal is input to the travel control circuit of the unmanned forklift, the travel control circuit detects the mark plate provided on the floor in front of the shelf, and from that point on, the travel control circuit detects the front of the shelf based on the signal from the obstacle detection sensor. It is determined whether there is an obstacle in the vehicle, and if it is determined that there is no obstacle, the unmanned forklift is moved forward as it is.If it is determined that there is an obstacle, the unmanned forklift is immediately stopped at the mark plate detection position, and thus the obstacle is Avoid things being pinched between shelves.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

First Embodiment First, a first embodiment shown in FIGS. 1 and 2 will be described. As shown in the figure, a reflection type photoelectric switch 3 (a projector and a light receiver are integrally incorporated) as an obstacle detection sensor is provided on the shelf 2 on the opposite side of the approach direction of the unmanned forklift 1. The photoelectric switch 3 is connected to a control panel 5 installed on the ground. A waiting line 6 is buried along the approach line of the unmanned forklift on the floor surface on the front side of the shelf 2, and the waiting line 6 is connected to the control panel 5.
It is connected to the. Further, a mark plate 7 for waiting for an unmanned forklift is installed at a position at a certain distance from the shelf 2 on the floor surface.

On the other hand, the unmanned forklift 1 has a reflector 4 mounted on the front surface of the vehicle body at a height corresponding to the photoelectric switch 3, and a mark plate detection sensor for detecting the mark plate 7 substantially at the center of the lower surface of the vehicle body. A standby line detection sensor 9 for detecting the standby line 6 is further attached to the rear side of the lower surface of the vehicle body, and the mark plate detection sensor 8 and the standby line detection sensor 9 are respectively used for controlling a traveling motor of an unmanned forklift. It is connected to the travel control circuit 10.

This embodiment is configured as described above, so that the unmanned forklift 1
The vehicle moves forward to take 11, and the mark plate detection sensor 8 detects the standby mark plate 7, and when the detection signal is input to the travel control circuit 10, the travel control circuit 10 starts detecting the standby line from that point. Based on the output signal of the sensor 9, it is determined whether or not an induced current is flowing through the standby line 6.

That is, if there is no obstacle in front of the shelf 2 as shown in FIG. 1, the light emitted from the light emitter of the photoelectric switch 3 is reflected by the reflecting mirror 4 and received by the light receiver. Then, the signal indicating the presence of the reflected light is input to the control panel 5, and the control panel 5 receives the signal and supplies an induced current to the standby line 6. The standby line detection sensor 9 detects a magnetic field generated by the induced current, and the detection signal is transmitted to the travel control circuit 10.
Therefore, the traveling control circuit 10 determines that there is no obstacle, and advances the unmanned forklift 1 without stopping the traveling motor.

On the other hand, when there is an obstacle 12 in front of the shelf 2 as shown in FIG. 2, the light emitted from the light emitter of the photoelectric switch 3 is blocked by the obstacle 12 and does not return to the light receiver. No induction current flows through the standby line 6 and no signal is output from the standby line detection sensor 9. Therefore, in this case, the travel control circuit 10 determines that there is an obstacle, cuts off the drive current to the travel motor, and activates the brake to immediately stop the unmanned forklift 1 at the mark plate detection position. Thus, it is possible to prevent the obstacle 12 from being caught between the unmanned forklift 1 and the shelf 2.

<Embodiment 2> Next, in Embodiment 2 shown in FIG. 3, a reflection type photoelectric switch 3 is provided on the unmanned forklift 1 side, and a reflection mirror 4 is provided on the shelf 2 side.
On the other hand, the mark plate 7 is provided on the floor surface at a position separated from the shelf 2 by a certain distance, and the mark plate detection sensor 8 is provided on the unmanned forklift 1.

Therefore, in the case of the second embodiment, the mark plate detection sensor 8
Is detected, and when the detection signal is input to the travel control circuit 10, the travel control circuit 10 determines the presence or absence of an obstacle based on the signal of the reflective photoelectric switch 3 from that point. That is, when the photoelectric switch 3 is outputting a light receiving signal,
When it is determined that there is no obstacle, the unmanned forklift 1 is moved forward as it is. When no light is received, it is determined that there is an obstacle, and the drive current to the traveling motor is cut off and the brake is operated to move the unmanned forklift 1 to the mark plate. Stop immediately at the detection position.

Third Embodiment A third embodiment shown in FIG. 4 uses a transmission type photoelectric switch instead of the reflection type photoelectric switch 3 in the first embodiment, specifically, the unmanned forklift 1 side. And a light receiver 14 is provided on the shelf 2 side, and a light reception signal of the light receiver 14 is input to the control panel 5 on the ground. Other configurations are the same as those of the first embodiment. ing. Therefore, the detection of the obstacle is performed in the same manner.

<Embodiment 4> Further, Embodiment 4 shown in FIG. 5 uses a transmission type photoelectric switch instead of the reflection type photoelectric switch 3 in Embodiment 2 described above, specifically, on the shelf 2 side. Floodlight 13
The light receiving device 14 is installed on the unmanned forklift 1 side, and the light receiving signal of the light receiving device 14 is input to the traveling control circuit 10. The other configuration is the same as that of the second embodiment. Therefore, the same obstacle detection operation as that of the second embodiment is performed. However, in the case of the fourth and second embodiments, the necessary control panel 5 on the ground can be omitted in the first and third embodiments. Has economic advantages.

(Effects of the Invention) As described above in detail, according to the present invention, during unloading or loading work on a shelf by an unmanned forklift, the problem of interference with an obstacle when there is an obstacle in front of the shelf is solved. This can be avoided beforehand and greatly helps to improve safety.

[Brief description of the drawings]

1 and 2 are explanatory diagrams showing a first embodiment of the present invention, FIG. 3 is an explanatory diagram showing a second embodiment, FIG. 4 is an explanatory diagram showing a third embodiment, and FIG. 5 is a fourth embodiment. FIG. DESCRIPTION OF SYMBOLS 1 ... Unmanned forklift 2 ... Shelf 3 ... Photoelectric switch 4 ... Reflector 7 ... Mark plate 8 ... Mark plate detection sensor 10 ... Travel control circuit

Claims (1)

(57) [Claims] 1. An apparatus for detecting an obstacle existing between an unmanned forklift and a shelf, comprising: a mark plate installed on a floor at a predetermined distance from the shelf; and a mark plate provided on the unmanned forklift. A mark plate detection sensor that detects the mark plate and outputs a detection signal thereof; an obstacle detection sensor that detects an obstacle between the unmanned forklift and the shelf and outputs the detection signal; and the mark plate detection sensor. An obstacle detection device for an unmanned forklift, comprising: a traveling control circuit for stopping the unmanned forklift when receiving both signals of the obstacle detection sensor.