JP2005343626A - Cargo handling abnormality detection system of unmanned fork lift truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo handling abnormality detection system of an unmanned fork lift truck capable of preventing damage of a workpiece, facility, a fork or the like. <P>SOLUTION: When the unmanned fork lift truck 2 stops at a predetermined cargo handling position, a controller 13 calculates inclination θ with respect to a guide line 1 of the unmanned fork lift truck 2 from values D1 and D2 detected by a front part guide sensor 11 and a rear part guide sensor 12, calculates distance Smin and Smax and Tmin and Tmax in the lateral direction from each fork 8 and 9 at a retraction end and an advance end and the guide line 1 in a tip part using the inclination θ, and determines whether cargo handling operation can be safely performed or not from these values by protruding a pair of forks 8 and 9 without interfering with adjacent workpiece and facility to stop the cargo handling operation as abnormality when it determines that the cargo handling operation cannot be safely performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cargo handling abnormality detection system for an unmanned forklift.

  For example, Patent Document 1 discloses an unmanned forklift that travels along a guide line while detecting a guide line disposed on a floor surface with a guide sensor attached to a front portion of the forklift body. Such an unmanned forklift travels along a guide path, stops at a predetermined cargo handling position with respect to equipment such as a shelf and a conveyor, and loads and unloads workpieces by moving the fork up and down and back and forth from the forklift body.

Japanese Patent Laid-Open No. 9-25098

However, if the forklift main body is tilted with respect to the workpiece when the unmanned forklift as described above stops at the predetermined loading position, the fork may interfere with adjacent workpieces or equipment when the fork is advanced, As a result, the workpiece may not be held securely, and the workpiece may fall and damage the workpiece, equipment, fork, or the like.
The present invention has been made to solve such problems, and an object thereof is to provide a cargo handling abnormality detection system for an unmanned forklift that can prevent damage to a work, equipment, fork, and the like.

  A loading / unloading abnormality detection system according to the present invention is a loading / unloading abnormality detection system for an unmanned forklift that travels along a guide line and stops at a predetermined loading / unloading position to perform unloading by moving the fork forward and backward. And a pair of guide sensors for detecting a lateral deviation amount from the guide wire and a pair of guide sensors when the unmanned forklift stops at a predetermined cargo handling position for carrying out the cargo handling operation. Whether the unloading forklift can be safely handled by this fork by calculating the inclination of the unmanned forklift with respect to the guide line from the detected value and calculating the lateral distance from the guideline of the fork tip of the unmanned forklift based on this inclination If it is determined that it cannot be performed safely, the cargo handling operation is suspended. It is intended and a device.

  When the unmanned forklift stops at a predetermined cargo handling position, the controller calculates the inclination of the unmanned forklift with respect to the guide line from the detection values of the pair of guide sensors, and uses the inclination to each fork tip at the backward end and the forward end. The lateral distance from the guide wire is calculated, and the degree of interference between the adjacent workpiece or equipment and the fork is detected from that value, and the fork protrudes without interfering with the adjacent workpiece or equipment to ensure safe cargo handling operation. It is determined whether or not it can be performed safely, and when it is determined that it cannot be performed safely, the cargo handling operation is stopped as a cargo handling abnormality.

  According to the present invention, when the unmanned forklift stops at a predetermined cargo handling position for carrying out the cargo handling operation, the horizontal direction from the guide wire detected by the pair of guide sensors attached to the front and rear parts of the unmanned forklift respectively. Whether the unloading forklift can be safely operated by this fork by calculating the inclination of the unmanned forklift with respect to the guide line from the amount of deviation and calculating the lateral distance from the guideline of the fork tip of the unmanned forklift based on this inclination Since the cargo handling operation is stopped when it is determined that it cannot be performed safely, damage to the workpiece, equipment, fork, etc. can be prevented.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
With reference to FIG. 1, a cargo handling abnormality detection system for an unmanned forklift according to an embodiment of the present invention will be described. This system has a guide wire 1 made of a magnetic bar embedded in the floor and an unmanned forklift 2 that travels along this guide wire 1. The unmanned forklift 2 has a forklift main body 3, and a pair of reach leg portions 4 and 5 extend forward from the left and right sides of the front portion of the forklift main body 3. In addition, driven wheels (not shown) are respectively disposed at the front portions of the pair of reach leg portions 4 and 5, and the drive wheels 6 are disposed at the rear portion of the forklift main body 3.

  Further, a mast portion 7 is erected on the pair of reach leg portions 4 and 5 of the forklift main body 3 so as to be movable in the length direction of the forklift main body 3, that is, in the front-rear direction via a not-shown legley. A pair of forks 8 and 9 are attached so as to be movable up and down along the line 7. When the mast portion 7 is moved in the front-rear direction of the forklift body 3 along the reach legs 4 and 5 of the forklift body 3, the pair of forks 8 and 9 also move forward and backward together with the mast portion 7.

  A bracket 10 is provided at the front portion of the forklift body 3 so as to protrude forward from the lower portion of the forklift body 3 on the center line C of the unmanned forklift 2. A part guide sensor 11 is attached. A rear guide sensor 12 is attached to the lower part of the rear portion of the forklift body 3 so as to be positioned on the center line C of the unmanned forklift 2. The unmanned forklift 2 is configured to travel along the guide line 1 while detecting the guide line 1 on the floor surface by the front guide sensor 11 and the rear guide sensor 12. Here, the front guide sensor 11 and the rear guide sensor 12 are magnetic sensors formed by arranging a plurality of Hall elements along the width direction of the forklift body 3, that is, the left-right direction. Lateral displacement amounts D1 and D2 from the guide wire 1 made of a magnetic rod are detected by the rear guide sensor 12.

  Although not shown, a stop mark plate for stopping the unmanned forklift 2 traveling along the guide line 1 is embedded in the floor, and the unmanned forklift 2 is stopped to detect this stop mark plate. A sensor is provided. This stop mark plate indicates a predetermined cargo handling position for the unmanned forklift 2 to transfer the workpiece 14 to a facility such as a shelf or a conveyor (not shown).

A controller 13 having a traveling control unit for controlling the drive wheels 6 and a cargo handling control unit for controlling the mast unit 7 and the pair of forks 8 and 9 is disposed at the rear part of the forklift body 3. The front guide sensor 11, the rear guide sensor 12, and a stop sensor (not shown) are electrically connected to the controller 13. The control device of the present invention is composed of the controller 13.
The controller 13 stores in advance the distance A between the forks 8 and 9 of the unmanned forklift 2 and the width W of each fork. For example, the front end of the front guide sensor 11 is used as a reference point of the forklift main body 2, and FIG. A distance L1 in the front-rear direction from the reference point to the tip of the fork when the pair of forks 8 and 9 are positioned at the retracted end as shown by a solid line, and a pair of forks 8 as shown by a broken line in FIG. And the distance L2 in the front-rear direction from the reference point to the fork tip when the 9 and 9 are positioned at the forward end are stored in advance.

  Next, the operation of the unloading forklift cargo handling abnormality detection system according to this embodiment will be described. The unmanned forklift 2 travels along the guide line 1 and stops when a stop mark plate representing a predetermined cargo handling position is detected by a stop sensor (not shown). Thus, when the unmanned forklift 2 stops at a predetermined cargo handling position with respect to equipment such as a shelf and a conveyor (not shown), the controller 13 detects the lateral displacement amount D1 detected by the front guide sensor 11 and the rear guide sensor 12 at this time, and From D2, the inclination θ of the unmanned forklift 2 with respect to the guide line 1 is calculated. Next, the front end of each fork from the inclination θ, the lateral displacement amount D1 of the front guide sensor 11, the distance A of the forks 8 and 9 stored in advance, the width W of each fork and the reference point at the backward end and forward end. From the distances L1 and L2 in the front-rear direction to the minimum value Smin of the lateral distance from the guide wire 1 at the tip of the fork 8 at the retracted end and the maximum of the lateral distance from the guide wire 1 at the tip of the fork 9 A value Smax, a minimum value Tmin in the lateral direction from the guide line 1 at the tip of the fork 8 at the forward end, and a maximum value Tmax in the lateral direction from the guide line 1 at the tip of the fork 9 are calculated.

At this time, when a predetermined work 14 arranged on a facility (not shown) is loaded on the unmanned forklift 2, the controller 13 uses the calculated values Smin, Smax, Tmin, and Tmax to set a pair of forks 8 and 9 adjacent to each other. If it is judged whether the workpiece 14 can be securely held by protruding without interfering with the equipment, that is, whether the loading operation can be performed safely, and if it is judged safe, a pair of forks 8 and 9 are moved up and down along the mast portion 7 to be positioned at a height corresponding to the work 14 and the mast portion 7 is moved forward along the pair of reach leg portions 4 and 5, thereby taking out the cargo.
On the other hand, when it is determined that the cargo taking operation cannot be performed safely, the controller 13 determines that the cargo handling operation is abnormal and stops the cargo taking operation.

Similarly, when the work held by the pair of forks 8 and 9 of the unmanned forklift 2 is lowered to a predetermined location on an unillustrated facility, the controller 13 calculates the pair of forks from the calculated values Smin, Smax, Tmin, and Tmax. 8 and 9 are projected without interfering with adjacent workpieces and equipment, and it is judged whether the workpiece can be placed at a predetermined location on the equipment, that is, whether the loading operation can be performed safely. If it is determined, the pair of forks 8 and 9 are moved up and down along the mast portion 7 to be positioned at a height corresponding to a predetermined location on the facility, and the mast portion 7 is moved along the pair of reach leg portions 4 and 5. Move forward to place the cargo.
If it is determined that the loading operation cannot be performed safely, the controller 13 determines that the loading operation is abnormal and stops the loading operation.

  As described above, the controller 13 starts the cargo handling operation only when it is determined that the cargo handling operation can be performed safely, and stops the cargo handling operation when it is determined that the controller 13 is not safe. The pair of forks 8 and 9 interferes with adjacent workpieces and equipment when projected forward 3, or the workpiece 14 falls without being held securely by the pair of forks 8 and 9. It is possible to prevent the work and equipment and the pair of forks 8 and 9 from being damaged.

When the controller 13 determines that the unloading operation cannot be performed safely, the controller 13 not only stops the unloading operation of the unmanned forklift 2 but also issues a transfer instruction to the unmanned forklift 2 that is fixed on the floor surface. A cargo handling abnormality detection signal can be transmitted from the controller 13 to an unillustrated ground control panel or the like to notify the operator of the abnormality.
In addition, after detecting the cargo handling abnormality and stopping the cargo handling operation in this manner, the controller 13 can be programmed to move the unmanned forklift 2 forward and backward to correct its posture.

  In the above-described embodiment, the controller 13 provided in the unmanned forklift 2 calculates the lateral distance from the guide wire 1 of each fork tip to determine whether the cargo handling operation is safe. However, instead, the control device of the present invention is disposed in the ground control panel that issues a transfer command to the unmanned forklift 2, and when the unmanned forklift 2 stops at a predetermined cargo handling position, The lateral displacements D1 and D2 detected by the guide sensor 11 and the rear guide sensor 12 are transmitted to the ground control panel, and the ground control panel transmits from the guide wire 1 at the tip of each fork 8 and 9 at the forward end and the backward end. When the lateral distance is calculated to determine whether the cargo handling operation can be performed safely, and when the cargo handling operation is started from the ground control panel to the unmanned forklift 2 or the cargo handling operation is stopped It can also be configured to send the cormorant directive.

In the above-described embodiment, the magnetic rod is used as the guide wire and the magnetic sensor is used as the pair of guide sensors. Instead, the guide wire drawn on the floor surface by a white line or the like is used as a pair of optical sensors. It can also be detected by a guide sensor. Further, a current flowing through an electric wire arranged as a guide wire can be detected by a pickup coil, and this can be used as a guide sensor.
In addition, even in unmanned forklifts that are guided by a laser or gyro sensor, the amount of lateral displacement at the front of the forklift body and the amount of lateral displacement at the rear of the forklift body are detected from the guide wire by the laser or gyrosensor, and the controller detects these Is used to calculate the lateral distance from the guide line of each fork tip at the forward end and the backward end to determine whether the cargo handling operation is safe, and the cargo handling operation is started only when it is judged safe. Thus, damage to the workpiece, equipment, fork, etc. can be prevented, and the same effect as in the above-described embodiment can be obtained.

It is a figure which shows the cargo handling abnormality detection system of the unmanned forklift which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Guide wire, 2 Unmanned forklift, 3 Forklift main body, 4,5 Reach leg part, 6 Driving wheel, 7 Mast part, 8,9 Fork, 10 Bracket, 11 Front guide sensor, 12 Rear guide sensor, 13 Controller, 14 Workpiece , C Center line, D1, D2 Lateral deviation amount, θ inclination, Smin, Smax, Tmin, Tmax Lateral distance from the guide line at the fork tip.

Claims (1)

In the unloading forklift abnormality detection system of an unmanned forklift that travels along a guide line and stops at a predetermined loading position and moves the fork forward and backward,
A pair of guide sensors attached to the front and rear of the unmanned forklift and for detecting the amount of lateral deviation from the guide wire;
When the unmanned forklift stops at a predetermined cargo handling position for carrying out the cargo handling operation, the inclination of the unmanned forklift with respect to the guide wire is calculated from the detection values of the pair of guide sensors, and the fork tip of the unmanned forklift is based on this inclination. By calculating the lateral distance from the guide line of the part, whether or not the fork can be safely handled by this fork. An unloading forklift detection system for unmanned forklifts.

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