JPH0532392A - Preceding input article detection method for automatic crane - Google Patents

Abstract

PURPOSE:To detect a preceding input article even if conveyed articles are stacked in multiple stages. CONSTITUTION:An automatic crane 1 is provided with an ultrasonic distance sensor 30. While the automatic crane 1 is passed through a measuring position of the ultrasonic distance sensor 30 with a moving speed reduced at a forward position of an indicated position, an ultrasonic wave 32 is directed to a floor surface for scanning during the passing so as to detect presence of a preceding input article based on a receiving output waveform of the ultrasonic wave 32 returned by reflection. The automatic crane 1 is once stopped in the vicinity of a forward position of an indicated position and a propagation delay time of the ultrasonic wave 32 is detected by the ultrasonic distance sensor 30 to detect presence of a preceding input article. If absence of a preceding input article is determined, a conveyed article is conveyed to the indicated position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-insertion detecting method for an automatic crane which conveys an object to be conveyed to a designated position.

[0002]

2. Description of the Related Art As an example of a conventional automatic crane pre-insertion detection method, an automatic coil transfer crane implemented in a steelmaking plant or the like will be described with reference to the drawings. FIG. 7 is a side view for explaining the pre-insertion detection method.

In the figure, 1 is an automatic crane, 2 is a club, 3 is a hoisting drum, 4 is a wire rope, 5 is a hanging beam, 6 is a coil tong, and 10 is a coil. The coil
10 is a coil mounting table 7 placed on the floor of a warehouse, etc.
Is stored in. The storage position is inventoried by the upper CPU (not shown), and the next storage position is designated in advance by the address code and the like.

The automatic crane 1 moves to a designated position and stops based on the destination address designation of the crane output by the upper CPU. Next, after detecting the presence or absence of the coil previously stacked flat at the indicated position and other foreign matter, and confirming that there is no coil, etc., the coil 10 is mounted on the coil mounting table described above.
It is designed to be unloaded to the 7 storage position.

In the automatic crane, the pre-insertion detecting means at the indicated position is indispensable. In other words, if a foreign object such as a coil is stored in a place other than the predetermined position when manual operation is intervened for some reason rather than automatic operation, it will be different from the storage location of the upper CPU.
In addition to being unable to manage the inventory of coils, it will damage the coils. The pre-insertion detection is for preventing the above-mentioned problems.

[0006] As a conventional pre-incident detection method, a light beam projector 20 provided on a crane irradiates a light beam 21 toward the floor surface. The light beam 21 is reflected by a retro-reflecting plate 22 provided on the coil mounting table 7 provided on the floor surface, the recursive light beam 21 is detected by the photo sensor 23, and the coil is positioned at the indicated position depending on the presence or absence of the detection output signal.
It detects whether there is a foreign object such as 10. The retroreflective plate 22 is formed of a synthetic resin plate having a large number of minute prisms inside.

[0007]

However, in the conventional pre-incident detection method using the photosensor, a large number of retroreflective plates 22 are provided on the coil mounting table 7 (hereinafter simply referred to as the floor surface).
Since the above is provided, there are the following problems. That is, since the retroreflective plate 22 is soiled by the oil applied to the produced coil 10 for rust prevention, or the retroreflective plate 22 is scratched by the coil placed on the floor surface, the retroreflective plate is soiled. 22 Cleaning requires a lot of work for maintenance and replacement. Further, when the coils are stacked and stored for a plurality of stages due to the restriction of the floor area, there is a drawback that the photosensor cannot detect the pre-insertion. The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for detecting a pre-insertion of an automatic crane, which is capable of detecting a pre-insertion even if coils are stacked in multiple layers.

[0008]

A first aspect of the present invention is a method for detecting a pre-insertion item of an automatic crane that conveys an object to be instructed to unload, the automatic crane including an ultrasonic distance sensor. In addition, while moving the automatic crane, the moving speed is lowered before the designated position to pass the measurement position of the ultrasonic distance sensor, and the ultrasonic waves are scanned toward the designated position during the passage, and reflected and recursed. Based on the received output waveform of the ultrasonic waves, the presence or absence of pre-inserted items stacked at the indicated position is detected, and when it is judged that there is no pre-inserted items, the crane is stopped at the indicated position and the cargo is unloaded. There is.

A second aspect of the present invention is a method for detecting a pre-insertion item of an automatic crane that conveys an object to be conveyed to a designated position for unloading, the automatic crane including an ultrasonic distance sensor, and the automatic crane. To stop at the measurement position of the ultrasonic distance sensor provided in front of the indicated position, and detect the propagation time of the ultrasonic pulse to the indicated position by the ultrasonic distance sensor to detect the presence / absence of the pre-insertion. The feature is that when it is determined that there is no object, the object to be conveyed is conveyed to the indicated position and unloaded.

[0010]

Embodiments of the first invention will be described below with reference to the drawings. FIG. 1 is a side view for explaining the pre-insertion detection method, FIG. 2 is an explanatory view showing a measured distance result, and FIG. 3 is a flowchart. The same parts as those in the prior art are designated by the same reference numerals. In the first-inspection detection method of the automatic crane 1 of the first invention, the ultrasonic distance sensor 30 is used instead of the conventional light beam projector 20 and photosensor 23, and the conventional coil mounting table 7 provided on the floor surface is used. The retroreflective plate 22 described above is not provided.

The ultrasonic distance sensor 30 is attached to the suspension beam 5 via an L-shaped metal fitting 31 at a predetermined position L from the center line thereof. The ultrasonic distance sensor 30 has a transmitting / receiving unit arranged so that the ultrasonic pulse 32 emitted from the ultrasonic distance sensor 30 is directed to the floor surface.

In FIG. 1, the coils 10 are stacked flat on a coil mounting table 7 (hereinafter referred to as the floor) provided on the floor. The coil 11 shown by the broken line is placed in a zigzag pattern on the coil 10 in two stages, which is a so-called bale stack. The ultrasonic pulse 32 emitted from the ultrasonic distance sensor 30 toward the floor surface hits the floor surface and the top surfaces of the coils 10 and 11 to be reflected and reflected back, and is received by the ultrasonic distance sensor 30. By measuring the round-trip time T from the emission of the ultrasonic pulse 32 to the reception, the reflecting surface and the distance D are calculated by the following equation. D = S (T −TD) / 2 where TD is the sensor delay time, S is the speed of sound, and
It changes according to t as follows. S = 331.5 + 0.61t

Distance between the ultrasonic distance sensor 30 arranged at a predetermined height above the floor and the top surface of the floor, the coil 10 and the coil 11
A, B and C are stored in advance in the microcomputer mounted on the automatic crane 1 via the host CPU. Then, the measurement distance D between the floor surface of the sensor 30 and the top surfaces of the coil 10 and the coil 11 is measured.
By comparing with 0, D1, and D2, it is detected whether the coil 10 is in the flat stacking or the bale stacking at the indicated position. The distance C is set to be larger than the dead distance of the ultrasonic distance sensor 30. The upper CPU manages inventory and also commands the destination of the crane.

An embodiment according to the first invention will be described with reference to the drawings. FIG. 3 is a flowchart, and FIGS. 5 and 6 are waveform diagrams of the reception output current of ultrasonic waves. FIG. 5 shows a case where the coils are stacked flat, and FIG. 6 shows a case where the coils are stacked bale. According to the first invention method, when the crane travels toward the designated position and reaches the measurement position before the designated position, the traveling speed is reduced to pass the ultrasonic distance sensor 30 attachment position to continuously transmit ultrasonic waves. Then, scanning is performed toward the unloading surface, and the pre-insertion is detected based on the received output current waveform that reflects and returns.

Next, the automatic crane according to the first invention method
The operation 1 will be described with reference to FIGS. The automatic crane 1 moves in the direction of the arrow in Fig. 1 toward the designated position designated by the host CPU (S1). The automatic crane 1 reaches a preset measuring position of the ultrasonic distance sensor 30 before the indicated position, and the position is detected by a position detector (not shown), and the automatic crane 1 reduces the moving speed. When a speed detector (not shown) detects the speed,
Start distance measurement (S2).

An ultrasonic wave 32 is emitted from the ultrasonic distance sensor 30. Automatic crane 1 is moved, ultrasound 32 emitted is reflected by scanning the floor, is received by the receiver by recursive, and moving time of the automatic crane 1 T _C and X-axis, receiving the output current The output current waveform with A as the Y axis is input to the microcomputer (S3). As shown in Fig. 5, the received output currents reflected from the floor and the coil 10 are A0 and A1, respectively, and the current A1 is approximately T.
Only _C time is projected. The distance (D1-D2) is calculated from the received output current difference (A1-A0) (S3).

Next, the automatic crane 1 moves to the designated position (S4) and stops the emission of the ultrasonic waves 32 (S5). The presence / absence of pre-filled goods is judged based on the described result.
That is, whether or not the coil 10 or foreign matter is stacked flat on the floor is determined by the received output current A0 and the output current difference (A1-A0) (S6).

When it is judged that there is a pre-filled item, an automatic crane
1 stops (S7). When it is determined that there is no pre-filled item, the automatic crane 1 unloads the transported object at the position (S8).

In the above description, the case where the coils 10 are stacked flat has been described, but the case of bale stacking can also be detected in accordance with the above. When the automatic crane 1 is moved in the direction shown in FIG. 1, the ultrasonic waves 32 scan the floor surface, the coil 10, the coil 11, the coil 10, and the floor surface in this order. As a result, the received output current waveform becomes as shown in FIG. That is, the output current A2 of the coil 11 is larger than the output current A1 of the coil 10, and a step difference of the current difference (A2-A1) appears at the shoulder of the same waveform in the traveling direction. The existence of the stacked coils 11 is confirmed by the current A2 and the current difference (A2-A1). According to the method of the present invention, it is not necessary to stop the automatic crane 1, so that the transfer efficiency can be improved.

In the second invention method, the ultrasonic wave 32 emitted from the ultrasonic distance sensor 30 toward the floor hits the floor surface and the top surfaces of the coils 10 and 11 and is reflected back to the ultrasonic distance sensor. Received at 30. Since the received output current A is inversely proportional to the distance D from the reflecting surface (excluding the dead distance), the distance D is calculated from the output current A. Next, the operation of the automatic crane 1 according to the second invention method will be described with reference to FIG. The automatic crane 1 moves toward the designated position designated by the host CPU (S1). The automatic crane 1 has an ultrasonic distance sensor 30 in front of the indicated position.
It stops once at the measurement position of (S2), emits the ultrasonic wave 32, and measures the distance from the indicated position (S3).

It is determined whether or not there is a pre-filled item (S4). That is, if D0≈A, the coil 10 is absent, if D1≈B, the coil 11 is absent, and if D2≈C, the coils 10 and 11 are present. If D1 ≠ B, it is determined that the coil 11 is present. When it is determined that there is no pre-filled goods, the automatic crane 1 moves by the distance L by the positioning device (not shown), reaches the target designated position, and unloads (S5). If it is judged that there is pre-filled goods, the automatic crane 1 will make an emergency stop (S6).

The measured values of the measured distances D1 and D2 when the ultrasonic distance sensor 30 is moved in the direction orthogonal to the axis of the coil 11 in a state where the coils 10 and 11 are stacked are shown in FIG.
As shown by the white mark, the measurement distance is constant in a certain range,
The error was slight even if it deviated from the above range. Therefore, according to the present invention, even if the measurement position of the ultrasonic distance sensor 30 is slightly deviated from the target pointing position, the measurement error is small, and the presence / absence of the pre-insertion can be determined.

Although the above-mentioned embodiments have described the coil transfer automatic crane, the object to be transferred is not limited to the coil and can be applied not only to the automatic crane but also to a manual crane for transferring to a position where it cannot be visually observed. Is.

[0024]

As described above, in the first method of the invention, the moving speed of the automatic crane is lowered before the designated position to pass the measuring position of the ultrasonic distance sensor, and the ultrasonic wave is directed to the floor surface. The presence / absence of a pre-insertion object is detected based on the received output waveform of the reflected and reflected ultrasonic wave.

In the second invention method, the automatic crane is temporarily stopped before the pointing position, the distance of the pointing position is measured by ultrasonic pulses to detect the presence of the pre-insertion, and when there is no pre-insertion, the The goods are carried to the designated position and unloaded. Therefore, the conventional retroreflective plate is not necessary, and maintenance such as cleaning and maintenance required for it is completely unnecessary. Further, the structure of the pre-insertion detection device is simplified, and even if a plurality of conveyed objects are stacked, it can be detected, which is extremely convenient.

[Brief description of drawings]

FIG. 1 is a side view illustrating a method of detecting a pre-inserted object according to the present invention.

FIG. 2 is a drawing according to the present invention, which is an explanatory diagram of distance measurement.

FIG. 3 is a flowchart according to the first aspect of the invention.

FIG. 4 is a flowchart according to the second aspect of the invention.

FIG. 5 is a waveform diagram of an ultrasonic reception output current according to the present invention.

FIG. 6 is a diagram according to the present invention, which is a waveform diagram of an ultrasonic reception output current.

FIG. 7 is a side view illustrating a method of detecting a pre-insertion object according to a related art.

[Explanation of symbols]

1 automatic crane 10, 11 coils 30 ultrasonic distance sensor

Claims (2)

[Claims] 1. A method for detecting a pre-insertion of an automatic crane that conveys an object to be instructed to unload, wherein the automatic crane is equipped with an ultrasonic distance sensor, and the automatic crane is caused to travel. Decrease the moving speed before the indicated position to pass the measurement position of the ultrasonic distance sensor,
The ultrasonic wave was scanned toward the pointing position during the passage, and the presence or absence of the pre-inserted object stacked at the indicated position was detected based on the received output waveform of the reflected and returning ultrasonic wave, and it was determined that there was no pre-inserted object. At this time, the crane is stopped at the indicated position and the cargo is unloaded. 2. A method of detecting a pre-insertion item of an automatic crane that conveys an object to be instructed to unload, wherein the automatic crane is equipped with an ultrasonic distance sensor, and the automatic crane is caused to travel. Stop once at the measurement position of the ultrasonic distance sensor provided in front of the pointing position, detect the propagation time of the ultrasonic pulse to the pointing position by the ultrasonic distance sensor and detect the presence of pre-insertion, and judge that there is no pre-insertion In this case, the pre-incident detection method for the automatic crane is characterized in that the transported object is conveyed to the indicated position and unloaded.