JP2007269452A - Safety device for unmanned fork lift - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety device for an unmanned fork lift capable of safely performing conveying and transferring of a baggage by accurately determining an obstacle placed on a floor surface. <P>SOLUTION: A control part includes the ON state and the OFF state of object detection sensors 11-15 formed when a pallet P is detected by a pallet detection device of the unmanned fork lift. It is previously memorized making a predetermined on/off state arrangement pattern as a reference pattern. When the obstacle S exists at a front of the pallet P, when the unmanned fork lift approaches to a transfer working position, at least one sensor of the five object detection sensors 11-15 detects the obstacle S and becoming in the on state. At this time, since the on/off state arrangement pattern formed by the pallet detection device is not coincident with the reference pattern, the control part stops traveling of the unmanned fork lift 1 and stops transferring of the baggage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a safety device for an unmanned forklift, and more particularly to a safety device for an unmanned forklift that transports and transfers a load in a warehouse, a factory, or the like.

Conventionally, a conveyance system that conveys a load by using an unmanned forklift is known. When transporting loads by unmanned forklifts and stacking them in multiple stages on the floor of the loading place, if the loads already in the loading place are not in the correct state, stable loading There is a risk that it may not be possible or the cargo will collapse.
Therefore, in the unmanned forklift disclosed in Patent Document 1, the state of the load located below the fork is detected by a sensor, and the load transfer operation is performed based on the detection result.

JP-A-5-162998

However, for example, when a work implement such as a collapsed load or a stepladder is an obstacle, a sensor such as that used in the unmanned forklift disclosed in Patent Document 1 cannot distinguish the obstacle. Further, even if a sensor for detecting the load width or a sensor for detecting the height of the load is mounted on the unmanned forklift, it is difficult to discriminate between the load and the obstacle that are normally placed at the loading place.
The present invention has been made to solve such problems. The safety of an unmanned forklift that can accurately identify an obstacle placed on the floor and safely carry and transfer the load. An object is to provide an apparatus.

  An unmanned forklift safety device according to the present invention is an unmanned forklift safety device that transfers a load in a loading system in which a load is placed on a floor via a loading member, and is a front surface of the unmanned forklift. It consists of a plurality of object detection sensors arranged in the lower part in the width direction of the machine base and turned on when an object existing in front of each is detected, and includes a predetermined state including both an on state and an off state when a loading member is detected. Load loading member detection means for forming an on / off state arrangement pattern, and a predetermined on / off state arrangement pattern are stored in advance as a reference pattern and loaded when at least one object detection sensor of the load placement member detection means is turned on. A control unit for stopping the transfer of the load when the on / off state arrangement pattern obtained by the placing member detection means does not match the reference pattern; It is as it has.

The load mounting member can be configured to have an opening into which a fork of an unmanned forklift is inserted when transferring a load, and an object detection sensor corresponding to the opening is turned off.
A pallet can be used as the load placement member, and at this time, each object detection sensor of the load placement member detection means can be arranged at a height for detecting the pallet placed on the floor surface.
Moreover, it is preferable to further include a load detection sensor that is attached to a position higher than the plurality of object detection sensors of the unmanned forklift and detects whether or not there is a load ahead.

  According to the present invention, it is possible to accurately identify an obstacle placed on the floor surface and safely carry and transfer the load.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1 FIG.
A reach unmanned forklift 1 having a safety device according to Embodiment 1 of the present invention will be described with reference to FIGS. Here, it is assumed that the load W is transported in a state of being placed on the pallet P that is a load placing member and is stacked and stored on a floor surface at a predetermined loading place. The unmanned forklift 1 has a pair of reach leg portions 3 and 4 extending forward from the left and right sides of the lower part of the machine base 2. A pair of mast portions 5 and 6 are erected at the front portion of the machine base 2, and both the mast parts 5 and 6 are in the longitudinal direction of the machine base 2 with respect to the pair of reach leg portions 3 and 4, that is, the machine. The table 2 is disposed so as to be movable in the front-rear direction. A pair of forks 7 and 8 are attached along the mast portions 5 and 6 so as to be movable up and down. Between the pair of reach leg portions 3 and 4, a bracket 9 formed so as to protrude from the lower part of the machine base 2 to the front by substantially the same length as the reach leg portions 3 and 4 is disposed. A guide sensor 10 is attached to the lower surface of the.

  Five reach detection sensors 11 to 15 that turn on when an object located in front is detected are sequentially attached to one reach leg portion 3, the bracket 9, and the other reach leg portion 4. That is, the first object detection sensor 11 and the second object detection sensor 12 are arranged at a distance from each other in the width direction of the machine base 2 at the lower part of the front surface of the front end portion of one reach leg portion 3. The third object detection sensor 13 is disposed at the lower front part of the front part, and the fourth object detection sensor 14 and the fifth object detection sensor 15 are provided at the lower part of the front part of the front end of the other reach leg part 4. They are spaced apart from each other in the direction. Therefore, these five object detection sensors 11 to 15 are arranged at intervals in the width direction of the machine base 2.

  In addition, each object detection sensor 11-15 is formed from the reflection type sensor. In addition, a load detection sensor 16 for detecting whether or not there is a load W in the front is attached to a position higher than the third object detection sensor 13 on the front upper portion of the front end portion of the bracket 9. The load detection sensor 16 is also formed from a reflective sensor. Further, driven wheels 17 are disposed on the lower surfaces of the front end portions of the reach leg portions 3 and 4, and drive wheels 18 are disposed on the rear portion of the machine base 2. A guide line (not shown) is provided on the floor surface of the travel path, and the unmanned forklift 1 is configured to travel on the travel path while detecting the guide line by the guide sensor 10.

  As shown in FIG. 3, the control unit 19 is mounted on the machine base 2. Five object detection sensors 11 to 15 are connected to the control unit 19, respectively, and the five object detection sensors 11 to 15 constitute a pallet detection device 20 as a loading member detection unit of the present invention. . The control unit 19 is connected to a traveling device 21 for traveling the unmanned forklift 1 by driving and controlling a drive motor connected to the drive wheels 18, and reach operation of the pair of mast units 5 and 6. And the transfer apparatus 22 for transferring the load W by controlling the raising / lowering operation | movement of a pair of forks 7 and 8 is connected. Although not shown, the control unit 19 is also connected to the guide sensor 10 and the load detection sensor 16.

  For example, as shown in FIG. 4, the pallet P that is a target to be detected by the pallet detection device 20 includes a pair of flat plate portions 23, and three column portions between the pair of plate portions 23. 24 are spaced apart from each other in the width direction. Of the three pillars 24, two openings for inserting the pair of forks 7 and 8 of the unmanned forklift 1 between the pillar 24 located in the center and the two pillars 24 located on both sides thereof. Each of the portions 25 is formed, and the three column portions 24 and the two openings 25 are arranged in the width direction.

  The five object detection sensors 11 to 15 of the unmanned forklift 1 have the first object detection sensor 11, the third object detection sensor 13, and the fifth object detection sensor 15 corresponding to the three column parts 24, respectively. The object detection sensor 12 and the fourth object detection sensor 14 are arranged so as to correspond to the two openings 25, respectively. Moreover, these five object detection sensors 11-15 are arrange | positioned in the height which can each detect the pillar part 24 and the opening part 25 of the pallet P mounted on the floor surface. For example, when the pallet P has a height of about 13 cm as a whole and each opening 25 is formed with an opening height of about 10 cm, each of the object detection sensors 11 to 15 has a height of 6 cm to the floor surface. It is preferable to arrange at a height H of about 7 cm.

For example, an instruction including information on a predetermined loading place and stacking height for transferring the load is output from the management computer or the ground control panel to the unmanned forklift 1, and the unmanned forklift 1 responds to this instruction. Based on this, it is configured to stop at the transfer work position corresponding to a predetermined loading place and transfer the load to a predetermined stacking height.
Moreover, the detection distance range of each object detection sensor 11-15 is mounted on the floor surface of a predetermined loading place, when the unmanned forklift 1 is located in the transfer work position corresponding to a predetermined loading place. The distance range in which the detected object can be detected is set.

  Here, as shown in FIG. 5, when the pallet P on which the load W is placed is placed on the floor surface of a predetermined loading place, the unmanned forklift 1 is transferred to the loading place. When positioned at the work position, the pallet detection device 20 detects the pallet P, so that both the on state and the off state of the five object detection sensors 11 to 15 are displayed as shown in the reference pattern of Table 1 below. A predetermined on / off state arrangement pattern is formed.

  That is, among the five object detection sensors 11 to 15, the first object detection sensor 11, the third object detection sensor 13, and the fifth object detection sensor 15 respectively detect the three column parts 24 of the pallet P. On the other hand, the second object detection sensor 12 and the fourth object detection sensor 14 are turned off corresponding to the two openings 25 of the pallet P, respectively. The control unit 19 stores in advance an on / off state arrangement pattern formed when the pallet P is detected by the pallet detection device 20 as a reference pattern in advance.

  Next, the operation of the safety device for the unmanned forklift 1 according to Embodiment 1 of the present invention will be described. Normally, when there is no obstacle in front of the pallet P placed on the floor surface at the predetermined loading place, the unmanned forklift 1 stops at the transfer work position corresponding to the predetermined loading place. The pallet P is detected by the pallet detection device 20, and the on / off state arrangement pattern formed by the pallet detection device 20 at this time coincides with the reference pattern stored in advance. Therefore, the control unit 19 determines that there is no obstacle and determines that the obstacle is normal, and the transfer device 22 performs the reach operation of the mast units 5 and 6 and the lift operation of the forks 7 and 8 to transfer the load. I do.

  For example, as shown in FIGS. 6 and 7, the load W that has collapsed is located on the front surface of the pallet P placed on the floor surface of a predetermined loading place and becomes an obstacle S. When the unmanned forklift 1 approaches the transfer work position, at least one of the five object detection sensors 11 to 15 of the pallet detection device 20 detects the obstacle S and is turned on. At this time, the on / off state arrangement patterns formed by the pallet detection device 20 are as shown in patterns A and B in Table 1, respectively. That is, in the case of FIG. 6, the first object detection sensor 11, the second object detection sensor 12, the fourth object detection sensor 14, and the fifth object detection sensor 15 detect the obstacle S and turn on. State, and only the third object detection sensor 13 is turned off. Moreover, in the case of FIG. 7, all the object detection sensors 11-15 detect the obstruction S, and will be in an ON state.

  For example, as shown in FIG. 8, when a work implement such as a stepladder is an obstacle S located in front of the pallet P placed on the floor surface of a predetermined loading place, When the unmanned forklift 1 approaches the transfer work position, at least one of the five object detection sensors 11 to 15 of the pallet detection device 20 detects the obstacle S and is turned on. The on / off state arrangement pattern formed by the pallet detection device 20 is as shown in pattern C in Table 1. That is, the first object detection sensor 11 and the third object detection sensor 13 detect the obstacle S and are turned on, and the second object detection sensor 12, the fourth object detection sensor 14, and the fifth object detection sensor 13 are turned on. The object detection sensor 15 is turned off.

  As described above, since all of the patterns A, B, and C formed by the pallet detection device 20 do not match the reference pattern stored in advance, the control unit 19 detects what the pallet detection device 20 detects. It is determined that the vehicle is an obstacle and is determined to be abnormal, and the traveling of the unmanned forklift 1 by the traveling device 21 is stopped, and the transfer of the load by the transfer device 22 is stopped. Therefore, the obstacle placed on the floor can be accurately identified and the load can be safely transferred and transferred.

  In addition, since a pattern representing a shape unique to the pallet P is formed using the five object detection sensors 11 to 15 and obstacles are discriminated based on this pattern, one normal rectangular parallelepiped load W is formed. Even when an obstacle is located in front of the pallet P, it can be easily identified as an obstacle. Further, even when two or more loads W or work implements are obstacles as described above, it is possible to distinguish between the normal pallet P placed at the loading place and the obstacles. In addition, when there is an obstacle, it is not restricted to the above-mentioned case, and when an object is located on the front of the pallet P placed at a predetermined loading place and becomes an obstacle. Since the on / off state arrangement pattern formed by the pallet detection device 20 does not match the reference pattern, the obstacle can be determined.

Embodiment 2. FIG.
Next, an unmanned forklift provided with a safety device according to Embodiment 2 of the present invention will be described with reference to FIG. This Embodiment 2 has the light projection parts 31a-35a and light-receiving parts 31b-35b which respond | correspond mutually, respectively instead of the five object detection sensors 11-15 which consist of a reflection type sensor in the above-mentioned Embodiment 1. Five object detection sensors are used. The pallet detection device 20 is configured by these five object detection sensors. Here, each object detection sensor composed of a pair of light projecting units and light receiving units corresponding to each other is turned off when the light emitted from the light projecting unit reaches the light receiving unit. When an object is positioned between the light receiving unit and light traveling from the light projecting unit to the light receiving unit is blocked, the light emitting unit is turned on.

  The light-receiving portions 31b to 35b of the five object detection sensors are one reach leg portion 3 of the unmanned forklift 1, the bracket 9, and the other reach leg portion in the same manner as in the place where the object detection sensors 11 to 15 are arranged in the first embodiment. 4 are sequentially attached to the lower part of the front surface of each tip. On the other hand, the light projecting portions 31a to 35a of the five object detection sensors are attached to the wall 36 or the like positioned on the back surface of the predetermined loading place, and the light projecting portions 31a and the third object detection sensors 31a and 3rd of the first object detection sensor. The light projecting unit 33a of the object detection sensor and the light projecting unit 35a of the fifth object detection sensor are arranged corresponding to the three column parts 24 of the pallet P, respectively, and the light projecting unit 32a and the second light detection unit 32a of the second object detection sensor. The light projecting portions 34 a of the four object detection sensors are arranged corresponding to the two openings 25 of the pallet P, respectively.

  Light emitted from the light projecting unit 32a of the second object detection sensor and the light projecting unit 34a of the fourth object detection sensor passes through the corresponding opening 25 of the pallet P, and is located at the transfer work position. By reaching the corresponding light receiving parts 32b and 34b of the unmanned forklift 1, these two object detection sensors are turned off. On the other hand, the light emitted from the light projecting unit 31a of the first object detection sensor, the light projecting unit 33a of the third object detection sensor, and the light projecting unit 35a of the fifth object detection sensor respectively correspond to the pallet P. These three object detection sensors are turned on by being blocked by the column portion 24 and not reaching the corresponding light receiving portions 31b, 33b, and 35b. The controller 19 stores in advance an on / off state arrangement pattern formed by the pallet detection device 20 in the absence of an obstacle as a reference pattern.

  Each of the light projecting portions 31a to 35a is set so that light can reach longer than the distance from the wall 36 to the transfer work position of the unmanned forklift 1, and the unmanned forklift 1 moves to the transfer work position. When the light from the light projecting parts 32a and 34a of the second and fourth object detection sensors reaches the corresponding light receiving parts 32b and 34b when the two object detection sensors are approaching, the two object detection sensors are turned off. It is comprised so that it may become.

  Normally, since there are no obstacles in front of the pallet P placed on the floor of the predetermined loading place, the unmanned forklift 1 approaches the transfer work position corresponding to the predetermined loading place and moves the object. When the detection distance range of the detection sensor is reached, the second object detection sensor and the fourth object detection sensor are turned off, and the first object detection sensor, the third object detection sensor, and the fifth object detection sensor are turned off. Is turned on, and the on / off state arrangement pattern formed by the pallet detection device 20 at this time matches the reference pattern stored in advance. Therefore, the control unit 19 determines that there is no obstacle, determines that the obstacle is normal, stops at the transfer work position, and transfers the load.

Further, for example, as shown in FIG. 10, when the load W that has collapsed is located on the front surface of the pallet P placed on the floor surface of a predetermined loading place and becomes an obstacle S When the obstacle S is positioned between the pair of light projecting parts 34a and the light receiving part 34b of the fourth object detection sensor, the light emitted from the light projecting part 34a of the fourth object detection sensor is caused by the obstacle S. Therefore, when the unmanned forklift 1 approaches the transfer work position and reaches the detection distance range of the object detection sensor, only the second object detection sensor is turned off, and the first object detection sensor, third The object detection sensor, the fourth object detection sensor, and the fifth object detection sensor are all turned on. Therefore, since the on / off state arrangement pattern formed by the pallet detection device 20 does not match the reference pattern stored in advance, the control unit 19 determines that the object detected by the pallet detection device 20 is an obstacle. Judgment is made and it is determined that there is an abnormality. The same applies to the case where the obstacle S is located between the light projecting unit 32a and the light receiving unit 32b of the second object detection sensor.
Therefore, the obstacle placed on the floor can be accurately identified and the load can be safely transferred and transferred.

  Further, in the first and second embodiments described above, when the control unit 19 determines that the object detected by the pallet detection device 20 is an obstacle, for example, an obstacle detection is performed on a management computer or a ground control panel. An abnormality detection signal can be transmitted to notify the operator.

  In the first and second embodiments, the unmanned forklift 1 is provided with a load detection sensor 16 for detecting whether or not there is a load ahead, at a position higher than the object detection sensor. The sensor 16 can detect the presence or absence of a front load independently of pallet detection by a plurality of object detection sensors. When the load detection sensor 16 detects that there is a load W on the pallet P, the load is transferred only when the on / off state arrangement pattern formed by the pallet detection device 20 matches the reference pattern. In this case, it is possible to transfer the load more safely after confirming the existence of the load.

  Further, the unmanned forklift 1 detects the load in front using the load detection sensor 16 or the load width sensor that detects the load width, the load height detection sensor that detects the height of the load, and the like. There is a known system that automatically recognizes and stops the transfer work position corresponding to a predetermined loading place only by obtaining information such as a lane number where the predetermined loading place is located from a management computer or a ground control panel. However, even in such a system, if the safety device according to the present invention is applied, the load detection sensor 16 or the like determines that the obstacle is properly placed at the loading place, and the wrong transfer work position. Even if the transfer operation is stopped and the transfer operation is started, the on / off state arrangement pattern formed by the pallet detection device 20 does not match the reference pattern, so that an obstacle can be identified and the transfer of the load is stopped. Rukoto can. Therefore, it is possible to prevent the unmanned forklift 1 from erroneously loading the obstacle or trying to receive the obstacle.

  In Embodiments 1 and 2 described above, a reflective photoelectric sensor or a photoelectric sensor in combination with a light projecting unit and a light receiving unit is used as the object detection sensor. However, the distance to the object located in front of each is measured. A plurality of distance measuring sensors can be arranged in the width direction of the machine base at the lower front of the unmanned forklift as object detection sensors. In this case, the ON state may be set when the distance measured by each distance measuring sensor is equal to or smaller than a predetermined value, and the OFF state may be set when the distance is larger than the predetermined value.

  Moreover, although Embodiment 1 and 2 demonstrated the case where the pallet P on which the load W was loaded was stacked in multiple stages, one pallet P on which the load W was loaded on the floor surface of one loading place. The present invention can also be applied to a case where only the base plate is placed flat.

  In the first embodiment described above, the pallet P on which the load W is placed is placed directly on the floor surface. However, as shown in FIG. 11, on the floor surface of a predetermined loading place, For example, a loading platform R having three leg portions 41 can be arranged as a loading platform, and a pallet P on which a load W is loaded can be mounted on the loading platform R. Also in this case, the five object detection sensors 11 to 15 of the unmanned forklift 1 detect the three leg portions 41 of the loading platform P and the two space portions 42 formed between the three leg portions 41, respectively. An on / off state arrangement pattern can be used as a reference pattern. Therefore, even if the loading platform R is used as a detection target of the loading platform detection means, the obstacle positioned in front of the loading platform R can be accurately identified and the load can be safely transferred and transferred.

  Similarly, in the second embodiment, such a loading platform R can be used as a detection target of the loading member detection means.

  In the first and second embodiments, the number and arrangement interval of the column parts 24 of the pallet P and the leg parts 41 of the loading platform R used as detection targets of the load placement member detection means, and the object detection that constitutes the load placement member detection means. The number of sensors used and the arrangement interval, and the on / off state arrangement pattern formed when the loading member is detected by the loading member detection means are not limited to the above-described forms. What is necessary is just to be comprised so that the on / off state arrangement | sequence pattern containing both an ON state and an OFF state may be formed when a load mounting member is detected by a member detection means.

It is a side view which shows the unmanned forklift provided with the safety device which concerns on Embodiment 1 of this invention. It is a top view which shows the unmanned forklift provided with the safety device which concerns on Embodiment 1 of this invention. It is a block diagram which shows the safety device which concerns on Embodiment 1 of this invention. FIG. 3 is a diagram showing a pallet in the first embodiment. It is a figure which shows the mode of the pallet detection apparatus at the normal time in Embodiment 1. FIG. It is a figure which shows the mode of the pallet detection apparatus at the time of abnormality in Embodiment 1. FIG. It is a figure which shows the mode of the pallet detection apparatus at the time of abnormality in Embodiment 1. FIG. It is a figure which shows the mode of the pallet detection apparatus at the time of abnormality in Embodiment 1. FIG. It is a figure which shows the mode of the pallet detection apparatus at the normal time in Embodiment 2. FIG. It is a figure which shows the mode of the pallet detection apparatus at the time of abnormality in Embodiment 2. FIG. It is a figure which shows the loading platform in the modification of Embodiment 1. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Unmanned forklift, 2 units, 3, 4 Reach leg part, 5, 6 Mast part, 7, 8 Fork, 9 Bracket, 10 Guide sensor, 11-15 Object detection sensor, 16 Load detection sensor, 17 Driven wheel, 18 Drive Wheel, 19 Control part, 20 Pallet detection device, 21 Traveling device, 22 Transfer device, 23 Plate part, 24 Column part, 25 Opening part, 31a-35a Light projecting part, 31b-35b Light receiving part, 41 Leg part, 42 Space, P pallet, R loading platform, S obstacle, W loading.

Claims (4)

A safety device for an unmanned forklift that transfers a load in a loading system in which a load is placed on a floor via a loading member,
It consists of a plurality of object detection sensors arranged in the front lower part of the unmanned forklift in the width direction of the machine base and each detecting an object existing in front of each, and both the on state and the off state are detected when the loading member is detected A loading member detection means for forming a predetermined on / off state array pattern including:
The predetermined on / off state arrangement pattern is stored in advance as a reference pattern, and the on / off state arrangement pattern obtained by the loading member detection unit when at least one object detection sensor of the loading member detection unit is turned on. A safety unit for an unmanned forklift, comprising: a control unit that stops transfer of a load when the value does not match the reference pattern.   2. The safety device for an unmanned forklift according to claim 1, wherein the load placing member has an opening into which a fork of an unmanned forklift is inserted when a load is transferred, and the object detection sensor corresponding to the opening is turned off.   The unloading forklift according to claim 1 or 2, wherein the load placing member is composed of a pallet, and each object detection sensor of the load placing member detecting means is disposed at a height for detecting the pallet placed on a floor surface. Safety device.   The unmanned vehicle according to any one of claims 1 to 3, further comprising a load detection sensor that is attached to a position higher than the plurality of object detection sensors of the unmanned forklift and detects whether or not there is a load ahead. Forklift safety device.

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