Cargo loading and unloading control device

Abstract

Provided is a cargo handling control device capable of improving the success rate of cargo handling by a forklift. A cargo handling control device (20) is provided with: a guide control unit (34) that, on the basis of the position of a pallet (11A) to be picked up with respect to a forklift (1) when the forklift (1) is at a start position (P0), performs control so that the forklift (1) approaches a cargo handling position (P) corresponding to the position of the pallet (11A) to be picked up; an approach determination unit (35) that determines whether or not the approach of the forklift (1) succeeds on the basis of the position of the pickup target pallet (11A) when the forklift (1) reaches the cargo loading / unloading position (P); and a reguidance control unit (37) that, when it is determined that the approach of the forklift (1) to the cargo loading / unloading position (P) has failed, performs control so that the forklift (1) approaches the cargo loading / unloading position (P) again on the basis of the position of the pickup target pallet (11A) with respect to the forklift (1).

Description

Technical Field

[0001] The invention relates to a cargo loading and unloading control device. Background Art

[0002] As a conventional cargo handling control device, for example, the technology described in Patent Document 1 is known. The cargo handling control device described in Patent Document 1 detects the position and posture of a transport object (target object) loaded with cargo on a pallet by a sensor when the forklift moves along a first path in a manner that crosses an installation area where a transport object (target object) is installed, and sets a second path to a target position with a predetermined position and posture relative to the transport object based on the position and posture of the transport object, and moves the forklift along the second path.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-70559 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, the above-mentioned prior art has the following problems. That is, although the probability is low, the position detection of the target object by the sensor may sometimes fail due to detection errors. If the position detection of the target object fails, even if the set path of the forklift is appropriate, the position of the forklift will be offset relative to the target object, and it may be impossible to pick up the goods from the pallet. In addition, errors may sometimes occur in the estimation of the forklift's own position and the guidance of the forklift due to obstacles and the like. If there is an estimation error in the forklift's own position or a guidance error in the forklift, the forklift will fail to approach the target object, and the position of the forklift will be offset relative to the target object, and it may be impossible to pick up the goods from the pallet.

[0008] An object of the present invention is to provide a cargo handling control device capable of improving the success rate of cargo handling by a forklift.

[0009] Solutions for solving problems

[0010] (1) One aspect of the present invention is a cargo loading and unloading control device for loading and unloading cargo by moving a forklift from a starting position toward a cargo loading and unloading object, comprising: an object detection unit for detecting the cargo loading and unloading object; a position calculation unit for calculating the position of the cargo loading and unloading object relative to the forklift based on detection data of the object detection unit; an approach control unit for controlling the forklift to approach the cargo loading and unloading position corresponding to the cargo loading and unloading object based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is at the starting position; and an approach determination unit for determining the position of the forklift based on the forklift reaching the cargo loading and unloading object. a cargo handling control unit that controls the forklift to load and unload cargo to the cargo loading and unloading object when the forklift reaches the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit; a cargo handling control unit that controls the forklift to load and unload cargo to the cargo loading and unloading object when the forklift reaches the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit ...; and a re-approach control unit that controls the forklift to approach the cargo loading and unloading position again when the forklift reaches the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit.

[0011] In such a cargo handling control device, first, the cargo handling object is detected by the object detection unit at the starting position, and the position of the cargo handling object relative to the forklift is calculated. Then, based on the position of the cargo handling object relative to the forklift, the forklift is controlled to approach the cargo handling position corresponding to the cargo handling object. When the forklift reaches the cargo handling position, the cargo handling object is detected by the object detection unit, and the position of the cargo handling object relative to the forklift is calculated. Then, based on the position of the cargo handling object relative to the forklift, it is determined whether the forklift has successfully approached the cargo handling position. In the case where it is determined that the forklift has failed to approach the cargo handling position, the forklift is controlled to approach the cargo handling position again based on the position of the cargo handling object relative to the forklift. In this way, in the case where the forklift has failed to approach the cargo handling position, by retrying the forklift to approach the cargo handling position, the probability of the forklift reaching the appropriate cargo handling position corresponding to the cargo handling object becomes higher. As a result, the success rate of cargo loading and unloading by the forklift is improved.

[0012] (2) In the above (1), when it is determined that the forklift has failed to approach the cargo loading and unloading position, the re-approach control unit may control the forklift to temporarily retreat from the cargo loading and unloading position and then approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift was at the cargo loading and unloading position.

[0013] In such a configuration, when the forklift fails to approach the cargo loading and unloading position, the object detection unit detects the cargo loading and unloading object at the cargo loading and unloading position, and calculates the position of the cargo loading and unloading object relative to the forklift. Then, based on the position of the cargo loading and unloading object relative to the forklift, the forklift is controlled to temporarily retreat relative to the cargo loading and unloading position and then approach the cargo loading and unloading position again. Therefore, the forklift is retried to approach the cargo loading and unloading position while fully ensuring the position accuracy of the cargo loading and unloading object relative to the forklift. Therefore, the probability of the forklift reaching the appropriate cargo loading and unloading position corresponding to the cargo loading and unloading object becomes higher.

[0014] (3) In the above (1), when it is determined that the forklift has failed to approach the cargo loading and unloading position, the re-approach control unit may control the forklift to temporarily retreat relative to the cargo loading and unloading position, and then control the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit.

[0015] In such a configuration, when the forklift fails to approach the cargo loading and unloading position, the forklift is first controlled to temporarily retreat relative to the cargo loading and unloading position. Then, based on the position of the cargo loading and unloading object relative to the forklift, the forklift is controlled to approach the cargo loading and unloading position again. Therefore, the travel distance of the forklift after setting the travel path for retrying the forklift's approach to the cargo loading and unloading position becomes shorter. Therefore, the probability of the forklift reaching the appropriate cargo loading and unloading position corresponding to the cargo loading and unloading object becomes higher.

[0016] (4) In the above (3), the re-approach control unit may control the forklift to temporarily retreat to the starting position relative to the cargo loading and unloading position, and then control the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is at the starting position.

[0017] In such a configuration, when the forklift fails to approach the cargo loading and unloading position, the forklift is temporarily retreated to the start position known in advance as position information, thereby simplifying the process.

[0018] (5) In the above (1), the cargo handling control device may further include a detection possibility determination unit, wherein, when the approach determination unit determines that the forklift has failed to approach the cargo handling position, the detection possibility determination unit determines whether the object detection unit at the cargo handling position can detect the cargo handling object, and when the detection possibility determination unit determines that the object detection unit at the cargo handling position can detect the cargo handling object, the re-approach control unit controls the forklift to temporarily retreat from the cargo handling position and then approach the cargo handling position again based on the position of the cargo handling object relative to the forklift calculated by the position calculation unit when the forklift is at the cargo handling position, and when the detection possibility determination unit determines that the object detection unit at the cargo handling position cannot detect the cargo handling object, the re-approach control unit controls the forklift to temporarily retreat from the cargo handling position and then control the forklift to approach the cargo handling position again based on the position of the cargo handling object relative to the forklift calculated by the position calculation unit.

[0019] In such a configuration, when the object detection unit can detect the cargo loading and unloading object at the cargo loading and unloading position, the forklift is controlled to temporarily retreat from the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift, and then approach the cargo loading and unloading position again. When the object detection unit cannot detect the cargo loading and unloading object at the cargo loading and unloading position, the forklift is controlled to temporarily retreat from the cargo loading and unloading position, and then, based on the position of the cargo loading and unloading object relative to the forklift, the forklift is controlled to approach the cargo loading and unloading position again. In this way, by switching the retry method of the forklift approaching the cargo loading and unloading position according to whether the object detection unit at the cargo loading and unloading position can detect the cargo loading and unloading object, the retry of the forklift approaching the cargo loading and unloading position can be appropriately implemented according to the use environment.

[0020] (6) In the above (5), when it is determined that the object detection unit cannot detect the cargo loading and unloading object, the reapproach control unit may control the forklift to temporarily retreat to the starting position relative to the cargo loading and unloading position, and then control the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is at the starting position.

[0021] In such a configuration, when it is determined that the object detection unit cannot detect the cargo handling object, the forklift is temporarily retreated to the start position known in advance as position information, thereby simplifying the process.

[0022] (7) In any of the above (1) to (6), the forklift may include a side shift cylinder for moving the fork in the left-right direction of the forklift, and the approach determination unit may determine whether a lateral offset of the forklift relative to the cargo loading and unloading object is less than a predetermined amount based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is in the cargo loading and unloading position, and when the lateral offset of the forklift relative to the cargo loading and unloading object is less than the predetermined amount, it may be determined that the forklift has successfully approached the cargo loading and unloading position, and when the lateral offset of the forklift relative to the cargo loading and unloading object is not less than the predetermined amount, it may be determined that the forklift has failed to approach the cargo loading and unloading position.

[0023] In such a configuration, when the lateral deviation of the forklift relative to the cargo loading and unloading object is less than a predetermined amount, it is considered that the fork can be adjusted to an appropriate position relative to the cargo loading and unloading object by moving the fork in the left-right direction using the side shift cylinder, and it is determined that the forklift has successfully approached the cargo loading and unloading position. Therefore, there is no need to retry the forklift's approach to the cargo loading and unloading position, and the process can be simplified.

[0024] (8) In any one of the above (1) to (7), the cargo loading and unloading control device may further include: a re-approach determination unit that determines whether the forklift has successfully re-approached the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position again; and a notification unit that issues an abnormality notification when the re-approach determination unit determines that the forklift has failed to re-approach the cargo loading and unloading position, and when the re-approach determination unit determines that the forklift has successfully re-approached the cargo loading and unloading position, the cargo loading and unloading control unit controls the forklift to load and unload the cargo on the cargo loading and unloading object.

[0025] In such a configuration, when the forklift fails to approach the cargo loading and unloading position again, by performing an abnormality notification, it is possible to notify the surroundings that the cargo loading and unloading is stopped because the forklift has failed to approach the cargo loading and unloading position twice in succession.

[0026] (9) In any one of the above (1) to (8), the object detection unit may detect the cargo handling object when the forklift is facing forward with respect to the cargo handling object.

[0027] In such a configuration, when the forklift is in either the starting position or the cargo loading and unloading position, the object detection unit detects the cargo loading and unloading object while the forklift is facing forward relative to the cargo loading and unloading object. Therefore, the number of object detection units used is suppressed to a necessary minimum, thereby achieving cost reduction.

[0028] (10) In any one of the above (1) to (8), the object detection unit may include: a first detection unit that detects the cargo loading and unloading object when the forklift is facing sideways relative to the cargo loading and unloading object; and a second detection unit that detects the cargo loading and unloading object when the forklift is facing frontally relative to the cargo loading and unloading object, and the position calculation unit calculates the position of the cargo loading and unloading object relative to the forklift based on detection data of the first detection unit when the forklift is in the starting position, and calculates the position of the cargo loading and unloading object relative to the forklift based on detection data of the second detection unit when the forklift is in the cargo loading and unloading position.

[0029] In such a configuration, when the forklift is in the starting position, the first detection unit detects the cargo loading and unloading object while the forklift is facing sideways relative to the cargo loading and unloading object. Then, the forklift is controlled to approach the cargo loading and unloading position. Therefore, even if the space in front of the cargo loading and unloading object is narrow, the forklift can be driven to the cargo loading and unloading position corresponding to the cargo loading and unloading object to load and unload the cargo.

[0030] (11) In any of the above (1) to (10), the cargo loading and unloading object may be a pallet having a pair of fork holes for inserting a pair of left and right forks of a forklift, the position calculation unit calculates the position and posture of the pallet relative to the forklift based on the detection data of the object detection unit, the approach control unit controls the forklift to approach the cargo loading and unloading position corresponding to the position of the pallet based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift is in the starting position, the approach determination unit determines whether the forklift has successfully approached the cargo loading and unloading position based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position, the cargo loading and unloading control unit controls the forklift to pick up the pallet as cargo loading and unloading when the approach determination unit determines that the forklift has successfully approached the cargo loading and unloading position, and the re-approach control unit controls the forklift to approach the cargo loading and unloading position again based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position.

[0031] In such a configuration, when the forklift fails to approach the cargo loading and unloading position, the forklift can be retried to approach the cargo loading and unloading position, thereby increasing the probability that the forklift will reach the appropriate cargo loading and unloading position corresponding to the position of the cargo pallet to be loaded and unloaded. As a result, the success rate of picking up cargo by the forklift is improved.

[0032] (12) In the above (11), the cargo loading and unloading control device may further include: a pickup possibility determination unit, which, when the approach determination unit determines that the forklift has failed to approach the cargo loading and unloading position, determines whether it is possible to successfully pick up the pallet by the forklift approaching the cargo loading and unloading position again based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position; and an abnormal stop control unit, which, when the pickup possibility determination unit determines that it is impossible to successfully pick up the pallet even if the forklift approaches the cargo loading and unloading position again, controls the forklift to stop abnormally, and when the pickup possibility determination unit determines that it is possible to successfully pick up the pallet by the forklift approaching the cargo loading and unloading position again, controls the forklift to approach the cargo loading and unloading position again based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit.

[0033] In such a configuration, when it is determined that the forklift fails to approach the cargo loading and unloading position, and when it is determined that the pallet cannot be successfully picked up even if the forklift approaches the cargo loading and unloading position again, the forklift is stopped due to abnormal driving, and there is no need to retry the forklift to approach in vain. Therefore, the total cargo loading and unloading time can be reduced.

[0034] (13) In the above (12), the forklift may include a side shift cylinder for moving the fork in the left-right direction of the forklift, and the approach determination unit determines whether a first condition is satisfied that the roll angle of the forklift relative to the pallet is less than a predetermined first specified angle, a second condition is satisfied that the pitch angle of the forklift relative to the pallet is less than a predetermined second specified angle, a third condition is satisfied that the lateral offset amount of the forklift relative to the pallet is less than a predetermined specified amount, and a fourth condition is satisfied that the yaw angle of the forklift relative to the pallet is less than a predetermined third specified angle. When all of the first, second, third and fourth conditions are satisfied, it is determined that the forklift has successfully approached the cargo loading and unloading position. When any one of the first, second, third and fourth conditions is not satisfied, it is determined that the forklift has failed to approach the cargo loading and unloading position.

[0035] In such a configuration, when the position or posture of the cargo handling object relative to the forklift's pallet is offset by a certain amount or more, it is determined that the forklift has failed to approach the cargo handling position. Therefore, the success or failure of the forklift's approach to the cargo handling position can be appropriately determined.

[0036] (14) In the above (13), it may also be that the pickup feasibility determination unit determines that it is possible to successfully pick up the pallet by having the forklift approach the cargo loading and unloading position again when the first condition and the second condition are met, and when either the first condition or the second condition is not met, it may be determined that it is impossible to successfully pick up the pallet even if the forklift approaches the cargo loading and unloading position again.

[0037] In such a configuration, when, for example, the forklift's roll angle relative to the pallet of the cargo loading and unloading object exceeds the first specified angle due to an inclination of the pallet of the cargo loading and unloading object, or the forklift's pitch angle relative to the pallet of the cargo loading and unloading object exceeds the second specified angle, there is no need to perform a futile retry of the forklift's approach.

[0038] (15) In any one of the above (11) to (14), the cargo loading and unloading control device may further include a re-approach determination unit, which determines whether the forklift has successfully re-approached the cargo loading and unloading position based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position again. If the re-approach determination unit determines that the forklift has failed to re-approach the cargo loading and unloading position, the re-approach control unit controls the forklift to approach the cargo loading and unloading position again based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit. If the re-approach determination unit determines that the forklift has successfully re-approached the cargo loading and unloading position, the cargo loading and unloading control unit controls the forklift to pick up the cargo from the pallet.

[0039] In such a configuration, when the forklift fails to approach the cargo loading and unloading position again, the forklift can be retried to approach the cargo loading and unloading position again, thereby increasing the probability that the forklift will reach the appropriate cargo loading and unloading position corresponding to the position of the cargo pallet to be loaded and unloaded. As a result, the success rate of picking up cargo by the forklift is further improved.

[0040] (16) In the above (15), the cargo loading and unloading control device may further include: a re-approach number determination unit, which determines whether the number of times the forklift has re-approached the cargo loading and unloading position has reached a predetermined upper limit value when the re-approach number determination unit determines that the forklift has failed to re-approach the cargo loading and unloading position; and an abnormal stop control unit, which controls the forklift to stop the forklift's travel abnormally when the re-approach number determination unit determines that the number of times the forklift has re-approached the cargo loading and unloading position has reached the upper limit value.

[0041] In such a configuration, when the number of retries of the forklift approaching the cargo handling position reaches the upper limit, the forklift is stopped due to abnormal travel, and the forklift does not need to retry approaching more than necessary. Therefore, the total cargo handling time can be reduced.

[0042] Effects of the Invention

[0043] According to the present invention, the success rate of cargo loading and unloading by a forklift can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a side view showing a forklift to which the cargo handling control device according to the embodiment of the present invention is applied.

[0045] Figure 2 It is a block diagram showing the structure of the cargo handling control device according to the first embodiment of the present invention.

[0046] Figure 3 This is a schematic plan view showing the operation of a forklift moving from a starting position to a cargo loading and unloading position to pick up cargo.

[0047] Figure 4 It is shown by Figure 2 A flowchart of the steps of the pickup control process performed by the controller shown.

[0048] Figure 5 It is shown Figure 4 Flowchart showing the details of step S111.

[0049] Figure 6 This is a schematic plan view showing an operation of retrying the forklift to approach the cargo loading and unloading position when the forklift fails to approach the cargo loading and unloading position.

[0050] Figure 7 It is a block diagram showing the structure of the cargo handling control device according to the second embodiment of the present invention.

[0051] Figure 8 It is shown by Figure 7 A flowchart of the steps of the pickup control process performed by the controller shown.

[0052] Fig. 9 This is a schematic plan view showing an operation of retrying the forklift to approach the cargo loading and unloading position when the forklift fails to approach the cargo loading and unloading position.

[0053] Fig.10 It is a block diagram showing the structure of the cargo handling control device according to the third embodiment of the present invention.

[0054] Fig.11 It is shown by Fig.10 A flowchart of the steps of the pickup control process performed by the controller shown.

[0055] Fig.12 This is a schematic plan view showing the operation of retrying the forklift to approach the cargo loading and unloading position when it is determined that the camera at the cargo loading and unloading position cannot detect the pickup target pallet if the forklift fails to approach the cargo loading and unloading position.

[0056] Fig.13 It is a block diagram showing the structure of a cargo handling control device according to a fourth embodiment of the present invention.

[0057] Fig.14 It is shown by Fig.13A flowchart of the steps of the pickup control process performed by the controller shown.

[0058] Fig.15 It is a schematic plan view showing the operation of a forklift moving from a start position to a cargo loading and unloading position to load and unload cargo.

[0059] Fig.16 It is a schematic plan view showing the operation of retrying the forklift to approach the cargo loading and unloading position when it is determined that the camera at the cargo loading and unloading position can detect the pickup target pallet when the forklift fails to approach the cargo loading and unloading position.

[0060] Fig.17 This is a schematic plan view showing the operation of retrying the forklift to approach the cargo loading and unloading position when it is determined that the camera at the cargo loading and unloading position cannot detect the pickup target pallet if the forklift fails to approach the cargo loading and unloading position.

[0061] Fig.18 It is a block diagram showing the structure of a cargo handling control device according to a fifth embodiment of the present invention.

[0062] Fig.19 It is shown by Fig.18 A flowchart of the steps of the pickup control process performed by the controller shown.

[0063] Fig. 20 The diagram (including a top view and a front view) shows an example of a case where the success rate of picking up a cargo becomes higher by retrying the approach of a forklift and an example of a case where the success rate of picking up a cargo does not become higher by retrying the approach of a forklift.

[0064] Fig.21 It is shown Fig.19 A flowchart showing the detailed contents of steps S111 and S131 is shown.

[0065] Fig. 22 It is a diagram (including a top view, a front view, and a cross-sectional view) showing a state in which a forklift fails to approach a cargo loading and unloading position.

[0066] Fig.23 It is a perspective view showing the dimensions of the fork holes and forks of the pallet.

[0067] Description of Reference Numerals

[0068] 1…forklift; 11A…pallet to be picked up (cargo loading and unloading object); 12…fork; 15…side shift cylinder; 20, 20A, 20B, 20C, 20D…cargo loading and unloading control device; 21…camera (object detection unit); 31, 31C…pallet position calculation unit (position calculation unit); 32…own position estimation unit (approach control unit); 33…path generation unit (approach control unit); 34…guidance control unit (approach control unit); 35, 35D…approach determination unit; 36, 36A, 36B, 36D…path regeneration unit (re-approach control unit); 37, 37A, 37B, 37D…re-guidance Control unit (re-approach control unit); 38, 38D…re-approach determination unit; 39, 39D…cargo loading and unloading control unit; 40…alarm control unit (notification unit); 41…evacuation control unit (re-approach control unit); 42…detection possibility determination unit; 45…pickup possibility determination unit; 46…re-approach number determination unit; 47…abnormal stop control unit; 51…side camera (first detection unit, object detection unit); 52…front camera (second detection unit, object detection unit); P0…starting position; P…cargo loading and unloading position; J…specified amount; θx…first specified angle; θy…second specified angle; θz…third specified angle. DETAILED DESCRIPTION

[0069] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the drawings, the same or equivalent elements are denoted by the same reference numerals, and repeated descriptions are omitted.

[0070] Figure 1 1 is a side view showing a forklift to which the cargo handling control device according to the embodiment of the present invention is applied. Figure 1 In the figure, the forklift 1 is a reach forklift. Here, the front-to-back direction of the forklift 1 is set as the X-axis direction, the left-right direction (lateral direction) of the forklift 1 is set as the Y-axis direction, and the up-down direction (height direction) of the forklift 1 is set as the Z-axis direction (refer to Fig. 22 The forklift 1 includes a travel device 2 and a cargo handling device 3 .

[0071] The travel device 2 includes a vehicle body 4, a pair of left and right front legs 5 extending from the lower portion of the vehicle body 4 to the front of the vehicle body 4, left and right front wheels 6 disposed at the top end (front end) of each front leg 5, and a rear wheel 7 which is a driving wheel and a steering wheel disposed at the left rear portion of the vehicle body 4. A caster (not shown) is disposed at the right rear portion of the vehicle body 4.

[0072] The cargo handling device 3 includes: a mast 8, which is arranged between the front legs 5 and can move along the front legs 5 in the front-back direction (X-axis direction) of the vehicle body 4; a pair of left and right forks 12, which are mounted on the mast 8 so as to be able to be raised and lowered in the up-down direction (Z-axis direction) via a lifting bracket 9 and a carrying bracket 10, and hold a pallet 11; a lifting cylinder 13, which raises and lowers the forks 12 via the lifting bracket 9 and the carrying bracket 10; and a front extension cylinder 14 (see Figure 2 ), which moves the fork 12 in the front-rear direction of the vehicle body 4 (advancing and retreating) by moving the mast 8 in the front-rear direction of the vehicle body 4; and the side shift cylinder 15 (refer to Figure 2 ), which moves the fork 12 in the lateral direction (Y-axis direction) via the carrying bracket 10.

[0073] The pallet 11 is a flat pallet made of plastic or wood, for example. The pallet 11 is square or substantially square in plan view. The cargo M is placed on the pallet 11. The pallet 11 is provided with a pair of fork holes 11a (see FIG. 1 ) for inserting the fork 12. Fig. 20 (b)).

[0074] Figure 2 1 is a block diagram showing the structure of a cargo handling control device according to a first embodiment of the present invention. Figure 2 The cargo handling control device 20 of the present embodiment is a device for performing cargo handling by automatic driving of the forklift 1 .

[0075] like Figure 3 As shown, the cargo handling control device 20 performs so-called picking up of the pallet 11 loaded on the cargo platform 18 of the truck 17. The cargo handling control device 20 causes the forklift 1 to move from the starting position P0 toward the pallet 11 of the picking target (hereinafter referred to as the picking target pallet 11A) to pick up the cargo. The picking target pallet 11A is the cargo handling target. The starting position P0 is the position where the forklift 1 starts moving toward the picking target pallet 11A from the side of the truck 17.

[0076] The cargo handling control device 20 includes a camera 21 , a laser sensor 22 , a map storage unit 23 , a travel drive unit 24 , a lift drive unit 25 , a reach drive unit 26 , a side shift drive unit 27 , an alarm 28 , and a controller 30 . These are mounted on the forklift 1 .

[0077] The camera 21 is an image sensor that captures a predetermined angle range (angle of view θ) including the front of the forklift 1 and outputs image data. The camera 21 captures the pallet 11 loaded on the cargo platform 18 of the truck 17. The camera 21 constitutes an object detection unit that detects the pickup target pallet 11A. When the forklift 1 is facing forward with respect to the pickup target pallet 11A, the camera 21 detects the pickup target pallet 11A and outputs image data as detection data.

[0078] The laser sensor 22 irradiates laser light around the forklift 1, receives reflected light from the laser light, detects the distance of an object around the forklift 1, and outputs detection data. As the laser sensor 22, for example, LIDAR (light detection and ranging) or a laser rangefinder is used.

[0079] The map storage unit 23 stores map data of an area where cargo is loaded and unloaded by the forklift 1. The map data includes buildings, pillars, shelves, walls, etc. The map data is created in advance by the laser sensor 22.

[0080] The travel drive unit 24 is a drive unit that drives the forklift 1. The travel drive unit 24 includes, for example, a travel motor that rotates the rear wheels 7 and a steering motor that steers the rear wheels 7, although both are not shown.

[0081] The lift drive unit 25 is a drive unit that extends and retracts the lift cylinder 13. The lift drive unit 25 is, for example, an electromagnetic control valve, and although not shown, the electromagnetic control valve is disposed between the hydraulic pump and the lift cylinder 13.

[0082] The extension drive unit 26 is a drive unit that causes the extension cylinder 14 to extend and retract. The extension drive unit 26 is, for example, an electromagnetic control valve, and although not shown, the electromagnetic control valve is disposed between the hydraulic pump and the extension cylinder 14.

[0083] The side shift drive unit 27 is a drive unit that causes the side shift cylinder 15 to extend and retract. The side shift drive unit 27 is, for example, an electromagnetic control valve, and although not shown, the electromagnetic control valve is disposed between the hydraulic pump and the side shift cylinder 15.

[0084] The alarm 28 is a device that issues an alarm when an abnormality occurs during cargo handling operations. The alarm 28 issues an alarm by means of an alarm sound or an alarm display.

[0085] The controller 30 is composed of a CPU, a RAM, a ROM, an input / output interface, etc. The controller 30 includes a pallet position calculation unit 31, a self-position estimation unit 32, a route generation unit 33, a guidance control unit 34, an approach determination unit 35, a route regeneration unit 36, a re-guidance control unit 37, a re-approach determination unit 38, a cargo handling control unit 39, and an alarm control unit 40.

[0086] The pallet position calculation unit 31 calculates the position and posture of the pickup target pallet 11A relative to the forklift 1 based on the image data of the camera 21. The pallet position calculation unit 31 calculates the position and posture of the pickup target pallet 11A relative to the forklift 1 at the starting position P0 and the cargo loading and unloading position P. The cargo loading and unloading position P is a position corresponding to the pickup target pallet 11A. Specifically, the cargo loading and unloading position P is a position in front of the pickup target pallet 11A. The pallet position calculation unit 31 constitutes a position calculation unit that calculates the position of the pickup target pallet 11A relative to the forklift 1.

[0087] The self-position estimating unit 32 estimates the self-position of the forklift 1 based on the detection data of the laser sensor 22 and the map data stored in the map storage unit 23. Specifically, the self-position estimating unit 32 estimates the self-position of the forklift 1 by matching the detection data of the laser sensor 22 with the map data using, for example, the SLAM (simultaneous localization and mapping) method. SLAM is a self-position estimating technology that estimates the self-position using sensor data and map data.

[0088] The path generation unit 33 generates a travel path D from the starting position P0 to the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 and the self-position of the forklift 1 estimated by the self-position estimation unit 32 (see Figure 3 The route generation unit 33 generates a travel route D such that the forklift 1 moves from the start position P0 to the cargo loading and unloading position P.

[0089] The guidance control unit 34 controls the travel drive unit 24 to guide the forklift 1 to the cargo loading and unloading position P along the travel route D generated by the route generation unit 33 based on the own position of the forklift 1 estimated by the own position estimation unit 32 .

[0090] The guidance control unit 34 cooperates with the self-position estimation unit 32 and the path generation unit 33 to form an approach control unit, which controls the forklift 1 to approach the cargo loading and unloading position P corresponding to the position of the object pallet 11A to be picked up based on the position of the object pallet 11A to be picked up relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 is at the starting position P0.

[0091] The approach determination unit 35 determines whether the forklift 1 has successfully approached the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 arrives at the cargo loading and unloading position P.

[0092] When the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P, the path regeneration unit 36 ​​regenerates a travel path to the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 at the cargo loading and unloading position P and the self-position of the forklift 1 estimated by the self-position estimation unit 32. The path regeneration unit 36 ​​generates a travel path such that the forklift 1 temporarily retreats relative to the cargo loading and unloading position P and then advances toward the cargo loading and unloading position P (see Figure 6 ).

[0093] The redirection control unit 37 controls the travel drive unit 24 to guide the forklift 1 to the cargo loading and unloading position P again according to the travel route generated by the route regeneration unit 36 ​​based on the own position of the forklift 1 estimated by the own position estimation unit 32 .

[0094] The redirection control unit 37 cooperates with the self-position estimation unit 32 and the path regeneration unit 36 ​​to form a re-approach control unit. When the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P, the re-approach control unit controls the forklift 1 to approach the cargo loading and unloading position P again based on the position of the pickup object pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31.

[0095] When it is determined that the forklift 1 has failed to approach the cargo loading and unloading position P, the re-approach control unit controls the forklift 1 to temporarily retreat from the cargo loading and unloading position P and then approach the cargo loading and unloading position P again based on the position of the pickup object pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 is at the cargo loading and unloading position P.

[0096] The re-approach determination unit 38 determines whether the forklift 1 has successfully re-approached the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 reaches the cargo loading and unloading position P again.

[0097] The cargo handling control unit 39 controls the lifting drive unit 25, the forward extension drive unit 26, and the side shift drive unit 27 to pick up the cargo from the pickup target pallet 11A when the approach determination unit 35 determines that the forklift 1 has successfully approached the cargo handling position P. In addition, when the re-approach determination unit 38 determines that the forklift 1 has successfully re-approached the cargo handling position P, the cargo handling control unit 39 controls the lifting drive unit 25, the forward extension drive unit 26, and the side shift drive unit 27 to pick up the cargo from the pickup target pallet 11A.

[0098] The alarm control unit 40 outputs an abnormality notification signal to the alarm device 28 to issue an alarm when the re-approach determination unit 38 determines that the forklift 1 has failed to re-approach the cargo loading and unloading position P. The alarm control unit 40 constitutes a notification unit that issues an abnormality notification when the re-approach determination unit 38 determines that the forklift 1 has failed to re-approach the cargo loading and unloading position P.

[0099] Figure 4 is a flow chart showing the steps of the pickup control process executed by the controller 30. Figure 3 As shown in (a) of FIG. 1 , this process is executed when the forklift 1 reaches the start position P0 . When the forklift 1 reaches the start position P0 , it faces forward with respect to the pickup target pallet 11A, and the camera 21 can recognize the pickup target pallet 11A.

[0100] exist Figure 4 In the process, the controller 30 first obtains image data from the camera 21 (step S101). Then, the controller 30 calculates the position and posture of the pickup target pallet 11A relative to the forklift 1 based on the image data from the camera 21 (step S102).

[0101] Next, the controller 30 estimates the position of the forklift 1 based on the detection data of the laser sensor 22 and the map data stored in the map storage unit 23 (step S103). Figure 3 As shown in (a), the controller 30 generates a travel path D from the start position P0, which is the current position of the forklift 1, to the cargo loading and unloading position P (step S104). Next, the controller 30 controls the travel drive unit 24 so that the forklift 1 approaches the cargo loading and unloading position P along the travel path D (step S105).

[0102] Next, the controller 30 estimates the position of the forklift 1 based on the detection data of the laser sensor 22 and the map data (step S106). Then, the controller 30 determines whether the forklift 1 has reached the cargo loading and unloading position P based on the position of the forklift 1 (step S107). When the controller 30 determines that the forklift 1 has not reached the cargo loading and unloading position P, the controller 30 executes the above-mentioned step S105 again.

[0103] like Figure 3 As shown in (b), when the controller 30 determines that the forklift 1 has reached the cargo loading and unloading position P, it controls the driving unit 24 to stop the forklift 1 (step S108). Next, the controller 30 obtains the image data of the camera 21 (step S109). Then, the controller 30 calculates the position and posture of the pickup target pallet 11A relative to the forklift 1 based on the image data of the camera 21 (step S110).

[0104] Next, the controller 30 determines whether the forklift 1 has successfully approached the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 (step S111 ).

[0105] Figure 5 is a flowchart showing the details of step S111. Figure 5 In step S151 , the controller 30 determines whether the lateral deviation amount of the forklift 1 relative to the pickup target pallet 11A is less than or equal to a predetermined amount based on the position of the pickup target pallet 11A relative to the forklift 1 (step S151 ).

[0106] The lateral offset of the forklift 1 is the offset in the lateral direction (left-right direction) of the forklift 1. The predetermined amount is a value set so that the fork 12 can be inserted into the fork hole 11a of the pickup target pallet 11A by moving the fork 12 in the lateral direction by the side shift cylinder 15. The predetermined amount is, for example, the maximum lateral displacement of the fork 12 from the center position in the left-right direction of the forklift 1.

[0107] When the controller 30 determines that the lateral offset of the forklift 1 relative to the pickup object pallet 11A is less than a specified amount, the controller 30 determines whether the offset angle of the forklift 1 relative to the pickup object pallet 11A is less than a predetermined specified angle based on the posture of the pickup object pallet 11A (step S152).

[0108] The offset angle of the forklift 1 is an offset amount of the yaw angle of the forklift 1. The predetermined angle is set so that the fork 12 can be inserted into the fork hole 11a of the pickup target pallet 11A by moving the fork 12 laterally by the side shift cylinder 15.

[0109] When the controller 30 determines that the deviation angle of the forklift 1 with respect to the pickup target pallet 11A is equal to or smaller than a predetermined angle, it determines that the forklift 1 has successfully approached the cargo loading and unloading position P (step S153).

[0110] When the controller 30 determines in step S151 that the lateral offset of the forklift 1 relative to the object pallet 11A for picking up cargo is not less than a specified amount, or when it determines in step S152 that the offset angle of the forklift 1 relative to the object pallet 11A for picking up cargo is not less than a specified angle, it determines that the forklift 1 has failed to approach the cargo loading and unloading position P (step S154).

[0111] Return to Figure 4 When the controller 30 determines in step S111 that the forklift 1 has successfully approached the cargo loading and unloading position P, it controls the lifting drive unit 25 and the side shift drive unit 27 to align the fork 12 with the fork hole 11a of the cargo pallet 11A to be picked up (step S112). Figure 3As shown in (c), the controller 30 controls the extension drive unit 26 and the lift drive unit 25 to insert the fork 12 into the fork hole 11a of the pickup target pallet 11A to pick up the goods from the pickup target pallet 11A (step S113).

[0112] When the controller 30 determines in step S111 that the forklift 1 has failed to approach the cargo loading and unloading position P, it estimates the own position of the forklift 1 based on the detection data of the laser sensor 22 and the map data stored in the map storage unit 23 (step S114).

[0113] Then, if Figure 6 As shown, the controller 30 generates a travel path from the current position of the forklift 1 to the cargo loading and unloading position P again (step S115). At this time, the controller 30 generates a travel path such that the forklift 1 moves forward after retreating a predetermined amount relative to the current position. Next, the controller 30 controls the driving unit 24 so that the forklift 1 approaches the cargo loading and unloading position P again according to the travel path (step S116).

[0114] Next, the controller 30 estimates the position of the forklift 1 based on the detection data of the laser sensor 22 and the map data (step S117). Then, the controller 30 determines whether the forklift 1 has reached the cargo loading and unloading position P based on the position of the forklift 1 (step S118). When the controller 30 determines that the forklift 1 has not reached the cargo loading and unloading position P, the controller 30 executes the above-mentioned step S116 again.

[0115] When the controller 30 determines that the forklift 1 has reached the cargo loading and unloading position P, it controls the driving unit 24 to stop the forklift 1 (step S119). Next, the controller 30 obtains the image data of the camera 21 (step S120). Then, the controller 30 calculates the position and posture of the pickup target pallet 11A relative to the forklift 1 based on the image data of the camera 21 (step S121).

[0116] Next, the controller 30 determines whether the forklift 1 has successfully approached the cargo loading and unloading position P again based on the position and posture of the pickup target pallet 11A relative to the forklift 1 (step S122). The details of step S122 are the same as those of step S111 described above.

[0117] When the controller 30 determines that the forklift 1 has successfully re-approached the cargo loading and unloading position P, the controller 30 executes the above-mentioned step S112. When the controller 30 determines that the forklift 1 has failed to re-approach the cargo loading and unloading position P, the controller 30 outputs an abnormality notification signal to the alarm 28 (step S123).

[0118] Here, the pallet position calculation unit 31 executes steps S101, S102, S109, S110, S120, and S121. The own position estimation unit 32 executes steps S103, S106, S114, and S117. The route generation unit 33 executes step S104. The guidance control unit 34 executes steps S105, S107, and S108. The approach determination unit 35 executes step S111. The route regeneration unit 36 ​​executes step S115. The re-guidance control unit 37 executes steps S116, S118, and S119. The re-approach determination unit 38 executes step S122. The cargo handling control unit 39 executes steps S112 and S113. The alarm control unit 40 executes step S123.

[0119] In the cargo handling control device 20 as described above, Figure 3 As shown in (a), the forklift 1 for picking up goods travels toward the truck 17 with the pallet 11 loaded on the cargo platform 18, and temporarily stops at a starting position P0 at a certain distance from the side of the truck 17, facing the front of the pallet 11A to be picked up.

[0120] In this state, the pickup target pallet 11A is photographed by the camera 21. Then, based on the image data of the camera 21, the position and posture of the pickup target pallet 11A relative to the forklift 1 are calculated, and a travel path D to the cargo loading and unloading position P in front of the pickup target pallet 11A is generated. Then, the forklift 1 approaches the cargo loading and unloading position P along the travel path D.

[0121] like Figure 3 As shown in (b), when the forklift 1 arrives at the cargo loading and unloading position P, the camera 21 captures the pickup target pallet 11A. Then, based on the image data of the camera 21, the position and posture of the pickup target pallet 11A relative to the forklift 1 are calculated, and the calculation result is used to determine whether the forklift 1 has successfully approached the cargo loading and unloading position P.

[0122] When the forklift 1 successfully approaches the cargo loading and unloading position P, Figure 3 Specifically, the fork 12 of the forklift 1 is inserted into the fork hole 11a of the pickup object pallet 11A, and the fork 12 is raised in this state, so that the pickup object pallet 11A is held by the fork 12. Then, the forklift 1 transports the pickup object pallet 11A to a designated place.

[0123] On the other hand, Figure 6 As shown in (a), when the forklift 1 deviates from the pickup target pallet 11A and the forklift 1 fails to approach the cargo loading and unloading position P, a travel path to the cargo loading and unloading position P is generated again. Figure 6 As shown in (b) and (c), the forklift 1 approaches the cargo loading and unloading position P again along the new driving path.

[0124] When the forklift 1 successfully approaches the cargo loading and unloading position P again, the forklift 1 picks up the cargo from the pickup target pallet 11A. When the forklift 1 also fails to approach the cargo loading and unloading position P again, the alarm 28 sounds an alarm.

[0125] As described above, in the present embodiment, first, the camera 21 detects the pickup target pallet 11A at the start position P0, and the position of the pickup target pallet 11A relative to the forklift 1 is calculated. Then, based on the position of the pickup target pallet 11A relative to the forklift 1, the forklift 1 is controlled to approach the cargo loading and unloading position P corresponding to the position of the pickup target pallet 11A. When the forklift 1 reaches the cargo loading and unloading position P, the camera 21 detects the pickup target pallet 11A, and the position of the pickup target pallet 11A relative to the forklift 1 is calculated. Then, based on the position of the pickup target pallet 11A relative to the forklift 1, it is determined whether the forklift 1 has successfully approached the cargo loading and unloading position P. In the case where it is determined that the forklift 1 has failed to approach the cargo loading and unloading position P, the forklift 1 is controlled to approach the cargo loading and unloading position P again based on the position of the pickup target pallet 11A relative to the forklift 1. Thus, when the forklift 1 fails to approach the cargo loading and unloading position P, the forklift 1 is retried to approach the cargo loading and unloading position P, and the probability of reaching the appropriate cargo loading and unloading position P corresponding to the position of the pickup target pallet 11A is increased. As a result, the success rate of cargo pickup by the forklift 1 is improved.

[0126] In addition, in the present embodiment, when it is determined that the forklift 1 has successfully approached the cargo loading and unloading position P, cargo is loaded and unloaded on the pickup target pallet 11A. Therefore, only when the forklift 1 fails to approach the cargo loading and unloading position P, the travel distance of the forklift 1 becomes longer. Therefore, the travel time of the forklift 1 can be reduced.

[0127] In addition, in the present embodiment, when the forklift 1 fails to approach the cargo loading and unloading position P, the camera 21 detects the pickup target pallet 11A at the cargo loading and unloading position P, and calculates the position of the pickup target pallet 11A relative to the forklift 1. Then, based on the position of the pickup target pallet 11A relative to the forklift 1, the forklift 1 is controlled to temporarily retreat from the cargo loading and unloading position P and then approach the cargo loading and unloading position P again. Therefore, the forklift 1 is retried to approach the cargo loading and unloading position P while fully ensuring the position accuracy of the pickup target pallet 11A relative to the forklift 1. Therefore, the probability that the forklift 1 reaches the appropriate cargo loading and unloading position P corresponding to the position of the pickup target pallet 11A becomes higher.

[0128] In addition, in the present embodiment, when the lateral deviation amount of the forklift 1 relative to the pickup target pallet 11A is less than a predetermined amount, it is considered that the fork 12 can be adjusted to an appropriate position relative to the pickup target pallet 11A by moving the fork 12 in the left-right direction using the side shift cylinder 15, and it is determined that the forklift 1 has successfully approached the cargo loading and unloading position P. Therefore, there is no need to retry the approach of the forklift 1 to the cargo loading and unloading position P, and the processing of the controller 30 can be simplified.

[0129] In the present embodiment, when the forklift 1 fails to approach the cargo loading and unloading position P again, an abnormality notification is performed to notify the surroundings that the pickup is stopped because the forklift 1 has failed to approach the cargo loading and unloading position P twice in succession.

[0130] In addition, in the present embodiment, when the forklift 1 is at any of the starting position P0 and the cargo loading and unloading position P, the forklift 1 is facing forward with respect to the cargo pallet 11A to be picked up, and the camera 21 detects the cargo pallet 11A to be picked up. Therefore, the number of cameras 21 used is suppressed to the necessary minimum, and cost reduction can be achieved.

[0131] Figure 7 2 is a block diagram showing the structure of a cargo handling control device according to a second embodiment of the present invention. Figure 7 In the embodiment, a cargo handling control device 20A of the present embodiment includes a controller 30A instead of the controller 30 of the first embodiment.

[0132] The controller 30A includes a pallet position calculation unit 31 , a self-position estimation unit 32 , a path generation unit 33 , a guidance control unit 34 , an approach determination unit 35 , an evacuation control unit 41 , a path regeneration unit 36A, a redirection control unit 37A, a re-approach determination unit 38 , a cargo loading and unloading control unit 39 , and an alarm control unit 40 .

[0133] When the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P, the retreat control unit 41 controls the travel drive unit 24 to temporarily retreat the forklift 1 relative to the cargo loading and unloading position P. The retreat control unit 41 controls the travel drive unit 24 to temporarily retreat the forklift 1 relative to the cargo loading and unloading position P to the start position P0.

[0134] When the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P, the route regeneration unit 36A regenerates a travel route to the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 at the start position P0 and the own position of the forklift 1 estimated by the own position estimation unit 32. The route regeneration unit 36A generates a travel route such that the forklift 1 moves toward the cargo loading and unloading position P in the same manner as the route generation unit 33.

[0135] The redirection control unit 37A controls the travel drive unit 24 to guide the forklift 1 to the cargo loading and unloading position P again according to the travel route generated by the route regeneration unit 36A based on the own position of the forklift 1 estimated by the own position estimation unit 32 .

[0136] The redirection control unit 37A cooperates with the self-position estimation unit 32, the retreat control unit 41 and the path regeneration unit 36A to form a re-approach control unit. When the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P, the re-approach control unit controls the forklift 1 to approach the cargo loading and unloading position P again based on the position of the pickup object pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31.

[0137] When it is determined that the forklift 1 has failed to approach the cargo loading and unloading position P, the re-approach control unit controls the forklift 1 to temporarily retreat to the starting position P0 relative to the cargo loading and unloading position P, and then controls the forklift 1 to approach the cargo loading and unloading position P again based on the position of the pickup object pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 is at the starting position P0.

[0138] Figure 8 is a flowchart showing the steps of the pickup control process executed by the controller 30A, and Figure 4 Corresponding. Figure 8 In the process, the controller 30A executes steps S101 to S111 in the same manner as in the above-mentioned first embodiment.

[0139] When the controller 30A determines in step S111 that the forklift 1 has failed to approach the cargo loading and unloading position P, Fig. 9 As shown in (a) and (b) of FIG. 1 , the travel drive unit 24 is controlled to return the forklift 1 to the start position P0 (step S125 ).

[0140] Next, the controller 30A obtains the image data from the camera 21 (step S126). Then, the controller 30A calculates the position and posture of the pickup target pallet 11A relative to the forklift 1 based on the image data from the camera 21 (step S127). Next, the controller 30A executes step S114 in the same manner as in the first embodiment described above.

[0141] Next, the controller 30A generates a travel path from the start position P0, which is the current position of the forklift 1, to the cargo loading and unloading position P again (step S115A). Next, the controller 30A controls the travel drive unit 24 so that the forklift 1 approaches the cargo loading and unloading position P again according to the travel path (step S116A). Then, the controller 30A executes the steps after step S117 in the same manner as in the first embodiment described above.

[0142] Here, the pallet position calculation unit 31 executes steps S101, S102, S109, S110, S126, S127, S120, and S121. The own position estimation unit 32 executes steps S103, S106, S114, and S117. The route generation unit 33 executes step S104. The guidance control unit 34 executes steps S105, S107, and S108. The approach determination unit 35 executes step S111. The retreat control unit 41 executes step S125. The route regeneration unit 36A executes step S115A. The re-guidance control unit 37A executes steps S116A, S118, and S119. The re-approach determination unit 38 executes step S122. The cargo handling control unit 39 executes steps S112 and S113. The alarm control unit 40 executes step S123.

[0143] In such a cargo handling control device 20A, if Fig. 9 As shown in (a) of FIG. 1 , when the forklift 1 reaches the cargo loading and unloading position P, the camera 21 captures the pickup target pallet 11A, and determines whether the forklift 1 has successfully approached the cargo loading and unloading position P, similarly to the first embodiment described above.

[0144] When the forklift 1 deviates from the pickup target pallet 11A and the forklift 1 fails to approach the cargo loading and unloading position P, as shown in FIG. Fig. 9 As shown in (b), the forklift 1 returns to the starting position P0.

[0145] Then, at the starting position P0, the camera 21 captures the pickup target pallet 11A, calculates the position and posture of the pickup target pallet 11A relative to the forklift 1, and generates a travel path to the cargo loading and unloading position P again. Fig. 9 As shown in (c), the forklift 1 approaches the cargo loading and unloading position P again along the travel path. The subsequent operation is the same as that of the first embodiment described above.

[0146] As described above, in the present embodiment, when the forklift 1 fails to approach the cargo loading and unloading position P, the forklift 1 is first controlled to temporarily retreat relative to the cargo loading and unloading position P. Then, based on the position and posture of the pickup target pallet 11A relative to the forklift 1, the forklift 1 is controlled to approach the cargo loading and unloading position P again. Therefore, the travel distance of the forklift 1 after setting the travel path for retrying the forklift 1 to approach the cargo loading and unloading position P becomes shorter. Therefore, the probability of the forklift 1 reaching the appropriate cargo loading and unloading position P corresponding to the position of the pickup target pallet 11A becomes higher.

[0147] In addition, in the present embodiment, when the forklift 1 fails to approach the cargo loading and unloading position P, the forklift 1 is temporarily retreated to the start position P0 known in advance as position information, thereby simplifying the processing of the controller 30A.

[0148] Fig.10 : is a block diagram showing the structure of a cargo handling control device according to a third embodiment of the present invention. Fig.10 In the embodiment, the cargo handling control device 20B of the present embodiment includes a controller 30B instead of the controller 30 of the first embodiment.

[0149] The controller 30B has a pallet position calculation unit 31, a self-position estimation unit 32, a path generation unit 33, a guidance control unit 34, an approach determination unit 35, a detection possibility determination unit 42, an evacuation control unit 41, a path regeneration unit 36B, a redirection control unit 37B, a re-approach determination unit 38, a cargo loading and unloading control unit 39 and an alarm control unit 40.

[0150] The detection possibility determination unit 42 determines whether the camera 21 can detect the pickup target pallet 11A at the cargo loading and unloading position P when the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P.

[0151] When the detection possibility determination unit 42 determines that the camera 21 cannot detect the pickup target pallet 11A at the cargo loading and unloading position P, the retreat control unit 41 controls the travel drive unit 24 to temporarily retreat the forklift 1 relative to the cargo loading and unloading position P. The retreat control unit 41 controls the travel drive unit 24 to temporarily retreat the forklift 1 relative to the cargo loading and unloading position P to the starting position P0.

[0152] When the detection possibility determination unit 42 determines that the camera 21 can detect the pickup target pallet 11A at the cargo loading and unloading position P, the path regeneration unit 36B regenerates a travel path to the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 at the cargo loading and unloading position P and the self-position of the forklift 1 estimated by the self-position estimation unit 32. At this time, the path regeneration unit 36B generates a travel path such that the forklift 1 temporarily retreats relative to the cargo loading and unloading position P and then advances toward the cargo loading and unloading position P (see Figure 6 ).

[0153] When the detection possibility determination unit 42 determines that the camera 21 cannot detect the pickup target pallet 11A at the cargo loading and unloading position P, the path regeneration unit 36B regenerates a travel path to the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 at the start position P0 and the self-position of the forklift 1 estimated by the self-position estimation unit 32. At this time, the path regeneration unit 36B generates a travel path such that the forklift 1 moves toward the cargo loading and unloading position P (see Fig.12 ).

[0154] The redirection control unit 37B controls the travel drive unit 24 to guide the forklift 1 to the cargo loading and unloading position P again according to the travel route generated by the route regeneration unit 36B based on the own position of the forklift 1 estimated by the own position estimation unit 32 .

[0155] The redirection control unit 37B cooperates with the self-position estimation unit 32, the retreat control unit 41 and the path regeneration unit 36B to form a re-approach control unit. When the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P, the re-approach control unit controls the forklift 1 to approach the cargo loading and unloading position P again based on the position of the pickup object pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31.

[0156] When the detection feasibility determination unit 42 determines that the camera 21 can detect the object pallet 11A for pickup at the cargo loading and unloading position P, the re-approach control unit controls the forklift 1 to temporarily retreat relative to the cargo loading and unloading position P and then approach the cargo loading and unloading position P again based on the position of the object pallet 11A for pickup relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 is at the cargo loading and unloading position P.

[0157] When the detection feasibility determination unit 42 determines that the camera 21 cannot detect the object pallet 11A for pickup at the cargo loading and unloading position P, the approach control unit controls the forklift 1 to temporarily retreat to the starting position P0 relative to the cargo loading and unloading position P, and then based on the position of the object pallet 11A for pickup relative to the forklift 1 calculated by the pallet position calculation unit 31, controls the forklift 1 to approach the cargo loading and unloading position P again.

[0158] Fig.11 is a flowchart showing the steps of the pickup control process executed by the controller 30B, and Figure 4 and Figure 8 Corresponding. Fig.11 In the process, the controller 30B executes steps S101 to S111 in the same manner as in the first and second embodiments described above.

[0159] When the controller 30B determines in step S111 that the forklift 1 has failed to approach the cargo loading and unloading position P, it determines whether the camera 21 can detect the object pallet 11A at the cargo loading and unloading position P based on the position and posture of the object pallet 11A relative to the forklift 1 calculated in step S110 (step S129).

[0160] At this time, when the pickup target pallet 11A enters the angle of view θ of the camera 21 (see Fig. 9 (a)), the camera 21 can detect the pickup target pallet 11A. When the pickup target pallet 11A is outside the viewing angle θ of the camera 21 (refer to Fig.12In (a)), the camera 21 cannot detect the pickup target pallet 11A.

[0161] When the controller 30B determines that the camera 21 can detect the pickup target pallet 11A at the cargo loading and unloading position P, the controller 30B executes step S114 in the same manner as in the first embodiment described above.

[0162] When the controller 30B determines that the camera 21 cannot detect the pickup target pallet 11A at the cargo loading and unloading position P, the controller 30B executes steps S125 to S127 and S114 in the same manner as in the second embodiment described above.

[0163] After executing step S114, the controller 30B generates a travel path from the current position of the forklift 1 to the cargo loading and unloading position P again (step S115B). Then, the controller 30B controls the travel drive unit 24 so that the forklift 1 approaches the cargo loading and unloading position P again according to the travel path (step S116B). Then, the controller 30B executes the steps after step S117 in the same manner as in the first and second embodiments described above.

[0164] Here, the pallet position calculation unit 31 executes steps S101, S102, S109, S110, S126, S127, S120, and S121. The own position estimation unit 32 executes steps S103, S106, S114, and S117. The route generation unit 33 executes step S104. The guidance control unit 34 executes steps S105, S107, and S108. The approach determination unit 35 executes step S111. The detection possibility determination unit 42 executes step S129. The retreat control unit 41 executes step S125. The route regeneration unit 36B executes step S115B. The re-guidance control unit 37B executes steps S116B to S119. The re-approach determination unit 38 executes step S122. The cargo handling control unit 39 executes steps S112 and S113. The alarm control unit 40 executes step S123.

[0165] In such a cargo handling control device 20B, Fig.12 As shown in (a), when the forklift 1 reaches the cargo loading and unloading position P, it is determined whether the forklift 1 successfully approaches the cargo loading and unloading position P. Then, when the forklift 1 fails to approach the cargo loading and unloading position P, it is determined whether the camera 21 can detect the pickup target pallet 11A.

[0166] When the pickup target pallet 11A can be detected by the camera 21, similarly to the first embodiment described above, a travel path to the cargo loading and unloading position P is generated again based on the position and posture of the pickup target pallet 11A at the cargo loading and unloading position P relative to the forklift 1. Then, the forklift 1 approaches the cargo loading and unloading position P again along the travel path.

[0167] When the pickup target pallet 11A cannot be detected by the camera 21, similarly to the second embodiment described above, Fig.12 As shown in (b), the forklift 1 returns to the starting position P0.

[0168] Then, at the starting position P0, the camera 21 captures the pickup target pallet 11A, detects the position and posture of the pickup target pallet 11A relative to the forklift 1, and generates a travel path to the cargo loading and unloading position P again. Fig.12 As shown in (c), the forklift 1 approaches the cargo handling position P again along the travel path. The subsequent operation is the same as that of the second embodiment described above.

[0169] As described above, in the present embodiment, when the camera 21 can detect the pickup target pallet 11A at the cargo loading and unloading position P, the forklift 1 is controlled to temporarily retreat from the cargo loading and unloading position P based on the position of the pickup target pallet 11A at the cargo loading and unloading position P relative to the forklift 1, and then approach the cargo loading and unloading position P again. When the camera 21 cannot detect the pickup target pallet 11A at the cargo loading and unloading position P, the forklift 1 is controlled to temporarily retreat from the cargo loading and unloading position P, and then the forklift 1 is controlled to approach the cargo loading and unloading position P again based on the position of the pickup target pallet 11A relative to the forklift 1. In this way, by switching the retry method of the forklift 1 approaching the cargo loading and unloading position P according to whether the camera 21 can detect the pickup target pallet 11A at the cargo loading and unloading position P, the retry of the forklift 1 approaching the cargo loading and unloading position P can be appropriately performed according to the use environment.

[0170] In addition, in the present embodiment, when it is determined that the camera 21 cannot detect the pickup target pallet 11A, the forklift 1 is temporarily retreated to the start position P0 known in advance as position information, thereby simplifying the processing of the controller 30B.

[0171] Fig.13 4 is a block diagram showing the structure of a cargo handling control device according to a fourth embodiment of the present invention. Fig.13 In the embodiment, a cargo handling control device 20C of the present embodiment includes a side camera 51 and a front camera 52 instead of the camera 21 of the third embodiment.

[0172] The side camera 51 and the front camera 52 are image sensors that capture images of the pallet 11 loaded on the cargo bed 18 of the truck 17. The side camera 51 and the front camera 52 constitute an object detection unit that detects the pickup target pallet 11A.

[0173] The side cameras 51 capture images in a predetermined angle range including the sides of the forklift 1 and output image data. The side cameras 51 are disposed on both left and right sides of the forklift 1. The side cameras 51 are first detection units that detect the pickup target pallet 11A when the forklift 1 is facing sideways relative to the pickup target pallet 11A.

[0174] The front camera 52 captures a predetermined angle range including the front of the forklift 1 and outputs image data similarly to the camera 21. The front camera 52 is a second detection unit that detects the pickup target pallet 11A when the forklift 1 faces forward relative to the pickup target pallet 11A.

[0175] In addition, the cargo handling control device 20C includes a controller 30C instead of the controller 30B of the third embodiment. The controller 30C includes a pallet position calculation unit 31C, an own position estimation unit 32, a path generation unit 33, a guidance control unit 34, an approach determination unit 35, a detection possibility determination unit 42C, an evacuation control unit 41, a path regeneration unit 36B, a re-guidance control unit 37B, a re-approach determination unit 38, a cargo handling control unit 39, and an alarm control unit 40.

[0176] The pallet position calculation unit 31C calculates the position and posture of the pickup target pallet 11A at the start position P0 relative to the forklift 1 based on the image data of the side camera 51. The pallet position calculation unit 31C calculates the position and posture of the pickup target pallet 11A at the cargo loading and unloading position P relative to the forklift 1 based on the image data of the front camera 52.

[0177] The pallet position calculation unit 31C constitutes a position detection unit, which calculates the position of the pickup object pallet 11A relative to the forklift 1 based on the detection data of the side camera 51 when the forklift 1 is at the starting position P0, and calculates the position of the pickup object pallet 11A relative to the forklift 1 based on the detection data of the front camera 52 when the forklift 1 is at the cargo loading and unloading position P.

[0178] The detection possibility determination unit 42C determines whether the front camera 52 can detect the pickup target pallet 11A at the cargo loading and unloading position P when the approach determination unit 35 determines that the forklift 1 has failed to approach the cargo loading and unloading position P.

[0179] Fig.14 is a flowchart showing the steps of the pickup control process executed by the controller 30C, and Fig.11 Corresponding. Fig.15 As shown in (a), this process is executed when the forklift 1 reaches the starting position P0. When the forklift 1 reaches the starting position P0, it faces the side (lateral) direction relative to the pickup object pallet 11A, and the side camera 51 can recognize the pickup object pallet 11A.

[0180] exist Fig.14 In the embodiment, the controller 30C first obtains the image data of the side camera 51 (step S101C). Then, the controller 30C calculates the position and posture of the pickup target pallet 11A based on the image data of the side camera 51 (step S102C). Then, the controller 30C executes steps S103 to S108 in the same manner as in the third embodiment described above.

[0181] After executing step S108, the controller 30C obtains the image data of the front camera 52 (step S109C). Then, the controller 30C calculates the position and posture of the pickup target pallet 11A based on the image data of the front camera 52 (step S110C). Then, the controller 30C executes step S111 in the same manner as in the third embodiment described above.

[0182] When the controller 30C determines in step S111 that the forklift 1 has failed to approach the cargo loading and unloading position P, it determines whether the front camera 52 at the cargo loading and unloading position P can detect the cargo pallet 11A to be picked up based on the position and posture of the cargo pallet 11A to be picked up relative to the forklift 1 calculated in step S110C (step S129C).

[0183] When the controller 30C determines that the front camera 52 can detect the pickup target pallet 11A at the cargo loading and unloading position P, the controller 30C executes steps S114 to S119 in the same manner as in the third embodiment described above.

[0184] When the controller 30C determines that the front camera 52 cannot detect the pickup target pallet 11A at the cargo loading and unloading position P, after executing step S125, the controller 30C obtains the image data of the side camera 51 (step S126C). Then, the controller 30C calculates the position and posture of the pickup target pallet 11A based on the image data of the side camera 51 (step S127C). Then, the controller 30C executes steps S114 to S119 in the same manner as in the third embodiment described above.

[0185] After executing step S119, the controller 30C obtains the image data of the front camera 52 (step S120C). Then, the controller 30C calculates the position and posture of the pickup target pallet 11A based on the image data of the front camera 52 (step S121C). Then, the controller 30C executes the steps after step S122 in the same manner as in the third embodiment described above.

[0186] Here, the pallet position calculation unit 31C executes steps S101C, S102C, S109C, S110C, S126C, S127C, S120C, and S121C. The own position estimation unit 32 executes steps S103, S106, S114, and S117. The route generation unit 33 executes step S104. The guidance control unit 34 executes steps S105, S107, and S108. The approach determination unit 35 executes step S111. The detection possibility determination unit 42C executes step S129C. The retreat control unit 41 executes step S125. The route regeneration unit 36B executes step S115B. The re-guidance control unit 37B executes steps S116B, S118, and S119. The re-approach determination unit 38 executes step S122. The cargo handling control unit 39 executes steps S112 and S113. The alarm control unit 40 executes step S123.

[0187] In such a cargo handling control device 20C, as Fig.15 As shown in (a), the forklift 1 travels straight along the front-rear direction of the truck 17 on one side (here, the right side) of the truck 17. Then, when the forklift 1 reaches the start position P0 facing the sideways direction relative to the pickup target pallet 11A, the travel of the forklift 1 is temporarily stopped.

[0188] In this state, the side camera 51 captures the pickup target pallet 11A. Then, based on the image data from the side camera 51, the position and posture of the pickup target pallet 11A relative to the forklift 1 are calculated, and a travel path D to the cargo loading and unloading position P corresponding to the position of the pickup target pallet 11A is generated. Fig.15 As shown in (b) of FIG. 1 , a travel path D is generated such that the forklift 1 moves forward while turning right toward the cargo loading and unloading position P after straightly retreating a certain distance. Then, the forklift 1 approaches the cargo loading and unloading position P along the travel path D.

[0189] like Fig.15 As shown in (c), when the forklift 1 reaches the cargo loading and unloading position P, the front camera 52 captures the pickup target pallet 11A. Then, based on the image data of the front camera 52, the position and posture of the pickup target pallet 11A relative to the forklift 1 are calculated to determine whether the forklift 1 has successfully approached the cargo loading and unloading position P.

[0190] In the case where the forklift 1 fails to approach the cargo loading and unloading position P, Fig.16 As shown in (a), when the pickup target pallet 11A can be detected by the front camera 52, the travel path to the cargo loading and unloading position P is generated again. Fig.16 As shown in (b) of FIG. 1 , a driving path is generated in which the forklift 1 temporarily turns right and moves backward relative to the cargo loading and unloading position P, and then turns right again and moves forward toward the cargo loading and unloading position P. Then, as shown in FIG. Fig.16 As shown in (c), the forklift 1 approaches the cargo loading and unloading position P again along the travel path.

[0191] In the case where the forklift 1 fails to approach the cargo loading and unloading position P, Fig.17 As shown in (a), when the front camera 52 cannot detect the pickup target pallet 11A, the forklift 1 returns to the starting position P0. Fig.17 As shown in (b) of FIG. 1 , the forklift 1 moves forward while turning right and moving backward relative to the cargo loading and unloading position P, thereby reaching the starting position P0.

[0192] Then, the side camera 51 takes another picture of the pickup target pallet 11A. Then, based on the image data from the side camera 51, the position and posture of the pickup target pallet 11A relative to the forklift 1 are calculated, and the travel path to the cargo loading and unloading position P is generated again. Fig.17 As shown in (c), the forklift 1 approaches the cargo loading and unloading position P again along the travel path.

[0193] As described above, in the present embodiment, when the forklift 1 is at the starting position P0, the forklift 1 is directed to the side with respect to the pickup target pallet 11A, and the side camera 51 detects the pickup target pallet 11A. Then, the forklift 1 is controlled to approach the cargo loading and unloading position P. Therefore, even if the space in front of the pickup target pallet 11A is narrow, the forklift 1 can be driven to the cargo loading and unloading position P corresponding to the position of the pickup target pallet 11A to load and unload cargo.

[0194] In the present embodiment, the process corresponding to the controller 30B of the third embodiment described above is executed, but the process corresponding to the controller 30 of the first embodiment described above or the controller 30A of the second embodiment described above may be executed.

[0195] Fig.18 Detailed description of the invention Figure 5 is a block diagram showing the structure of a cargo handling control device according to a fifth embodiment of the present invention. Fig.18 In the embodiment, the cargo handling control device 20D of the present embodiment includes a controller 30D instead of the controller 30 of the first embodiment.

[0196] The controller 30D has a pallet position calculation unit 31, a self-position estimation unit 32, a path generation unit 33, a guidance control unit 34, an approach determination unit 35D, a pickup possibility determination unit 45, a path regeneration unit 36D, a re-guidance control unit 37D, a re-approach determination unit 38D, a re-approach number determination unit 46, a cargo loading and unloading control unit 39D, an abnormal stop control unit 47 and an alarm control unit 40.

[0197] The approach determination unit 35D determines whether the forklift 1 has successfully approached the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 arrives at the cargo loading and unloading position P.

[0198] The approach determination unit 35D determines whether a first condition is satisfied that the roll angle of the forklift 1 relative to the object pallet 11A is less than a predetermined first specified angle, a second condition is satisfied that the pitch angle of the forklift 1 relative to the object pallet 11A is less than a predetermined second specified angle, a third condition is satisfied that the lateral offset amount of the forklift 1 relative to the object pallet 11A is less than a predetermined specified amount, and a fourth condition is satisfied that the yaw angle of the forklift 1 relative to the object pallet 11A is less than a predetermined third specified angle.

[0199] When all of the first condition, the second condition, the third condition, and the fourth condition are satisfied, the approach determination unit 35D determines that the forklift 1 has successfully approached the cargo loading and unloading position P. When any one of the first condition, the second condition, the third condition, and the fourth condition is not satisfied, the approach determination unit 35D determines that the forklift 1 has failed to approach the cargo loading and unloading position P.

[0200] When the approach determination unit 35D determines that the forklift 1 has failed to approach the cargo loading and unloading position P, the pickup feasibility determination unit 45 determines whether it is possible to successfully pick up the cargo object pallet 11A by the forklift 1 approaching the cargo loading and unloading position P again, based on the position and posture of the pickup object pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 arrives at the cargo loading and unloading position P.

[0201] The pickup determination unit 45 determines that the pickup of the target pallet 11A is likely to succeed when the forklift 1 approaches the cargo loading and unloading position P again when the first and second conditions described above are satisfied. The pickup determination unit 45 determines that the pickup of the target pallet 11A is unlikely to succeed even if the forklift 1 approaches the cargo loading and unloading position P again when any one of the first and second conditions described above is not satisfied.

[0202] When the pickup feasibility determination unit 45 determines that there is a possibility that the forklift 1 will approach the cargo loading and unloading position P again and that the pickup of the target pallet 11A is likely to be successful, the path regeneration unit 36D regenerates the travel path to the cargo loading and unloading position P based on the position and posture of the target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 at the cargo loading and unloading position P and the forklift 1's own position estimated by the own position estimation unit 32.

[0203] The redirection control unit 37D controls the travel drive unit 24 to guide the forklift 1 to the cargo loading and unloading position P again according to the travel route regenerated by the route regenerating unit 36D based on the own position of the forklift 1 estimated by the own position estimating unit 32 .

[0204] The redirection control unit 37D cooperates with the self-position estimation unit 32 and the path regeneration unit 36D to form a re-approach control unit. When the pickup feasibility determination unit 45 determines that the forklift 1 is likely to successfully pick up the object pallet 11A by approaching the cargo loading and unloading position P again, the re-approach control unit controls the forklift 1 to approach the cargo loading and unloading position P again based on the position of the object pallet 11A relative to the forklift 1 calculated by the position calculation unit.

[0205] When the re-approach determination unit 38D described later determines that the forklift 1 has failed to re-approach the cargo loading and unloading position P, the re-approach control unit controls the forklift 1 to approach the cargo loading and unloading position P again based on the position of the pickup target pallet 11A relative to the forklift 1 calculated by the position calculation unit.

[0206] The re-approach determination unit 38D determines whether the forklift 1 successfully re-approached the cargo loading and unloading position P based on the position and posture of the pickup target pallet 11A relative to the forklift 1 calculated by the pallet position calculation unit 31 when the forklift 1 reaches the cargo loading and unloading position P again.

[0207] When the re-approach determination unit 38D determines that the forklift 1 has failed to re-approach the cargo loading and unloading position P, the re-approach frequency determination unit 46 determines whether the number of times the forklift 1 has re-approached the cargo loading and unloading position P has reached a predetermined upper limit.

[0208] The cargo handling control unit 39D controls the lifting drive unit 25, the forward extension drive unit 26, and the side shift drive unit 27 to pick up the cargo pallet 11A to be picked up when the approach determination unit 35D determines that the forklift 1 has successfully approached the cargo handling position P. In addition, when the re-approach determination unit 38D determines that the forklift 1 has successfully approached the cargo handling position P, the cargo handling control unit 39D controls the lifting drive unit 25, the forward extension drive unit 26, and the side shift drive unit 27 to pick up the cargo pallet 11A to be picked up.

[0209] The abnormal stop control unit 47 controls the driving unit 24 to abnormally stop the driving of the forklift 1 when the pickup determination unit 45 determines that the forklift 1 cannot successfully pick up the target pallet 11A even if the forklift 1 approaches the cargo loading and unloading position P again. In addition, when the re-approaching number determination unit 46 determines that the number of re-approaches of the forklift 1 to the cargo loading and unloading position P has reached an upper limit, the abnormal stop control unit 47 controls the driving unit 24 to abnormally stop the driving of the forklift 1.

[0210] Fig.19 is a flowchart showing the steps of the pickup control process executed by the controller 30D, and Figure 4 correspond.

[0211] exist Fig.19 In the above-described first embodiment, the controller 30D executes steps S101 to S111. When the controller 30D determines in step S111 that the forklift 1 has successfully approached the cargo loading and unloading position P, steps S112 and S113 are executed.

[0212] When the controller 30D determines in step S111 that the forklift 1 has failed to approach the cargo loading and unloading position P, it determines whether it is possible to successfully pick up the cargo from the object pallet 11A by having the forklift 1 approach the cargo loading and unloading position P again, based on the position and posture of the object pallet 11A calculated relative to the forklift 1 in step S110 (step S131).

[0213] Here, as a case where the picking of the object pallet 11A fails, there are cases where the success rate of picking up the goods increases by re-approaching (retrying) the cargo loading and unloading position P by the forklift 1 and cases where the success rate of picking up the goods does not increase even if the forklift 1 re-approaches the cargo loading and unloading position P.

[0214] like Fig. 20 As shown in (a), the situation where the success rate of picking up the goods by the approach retry of the forklift 1 is increased is caused by the self-position estimation error and guidance error of the forklift 1 and the state where the forklift 1 is not in a position and posture to pick up the goods from the pickup target pallet 11A. As such a state, the state where the lateral offset (offset in the Y-axis direction) of the forklift 1 relative to the pickup target pallet 11A is large and the state where the yaw angle (tilt angle around the Z-axis) of the forklift 1 relative to the pickup target pallet 11A is large.

[0215] On the other hand, Fig. 20 As shown in (b), the situation where the success rate of picking up the goods does not increase even after the forklift 1 approaches and tries again is a state where the forklift 1 fails to pick up the goods on the picking up pallet 11A even if the forklift 1 moves along the ideal path and reaches the front of the picking up pallet 11A because the cargo platform 18 of the truck 17 or the picking up pallet 11A itself is tilted. As such a state, a state where the roll angle (tilt angle around the X-axis) of the forklift 1 relative to the picking up pallet 11A is large and a state where the pitch angle (tilt angle around the Y-axis) of the forklift 1 relative to the picking up pallet 11A is large.

[0216] The offset of the forklift 1 in the X-axis direction relative to the pallet 11A to be picked up can be dealt with by changing the front-to-back position of the fork 12 using the extension cylinder 14 or by changing the front-to-back position of the fork 12 by moving the forklift 1 forward and backward. The offset of the forklift 1 in the Z-axis direction relative to the pallet 11A to be picked up can be dealt with by changing the height position of the fork 12 using the lift cylinder 13.

[0217] Fig.21 It is shown Fig.19 A flowchart showing the detailed contents of steps S111 and S131 is shown.

[0218] exist Fig.21 In the process, the controller 30D first determines whether the tilt angle of the forklift 1 relative to the pickup object pallet 11A is less than a predetermined first specified angle θx based on the posture of the pickup object pallet 11A relative to the forklift 1 obtained in step S110 (step S161). In other words, the controller 30D determines whether the first condition that the tilt angle of the forklift 1 relative to the pickup object pallet 11A is less than a predetermined first specified angle θx is satisfied.

[0219] The first predetermined angle θx is an angle at which the fork 12 can be inserted into the fork hole 11a of the pickup target pallet 11A when the forklift 1 is tilted about the X-axis relative to the pickup target pallet 11A (see Fig. 22 (b)).

[0220] Specifically, if Fig.23 As shown, when the width of the fork 12 is set to Fw, the distance between the centers of the two forks 12 is set to Fd, the thickness of the fork 12 is set to Fh, and the height of the fork hole 11a of the object pallet 11A is set to Ph, when the inclination angle of the forklift 1 relative to the object pallet 11A is greater than the first specified angle θx as represented by the following formula, the fork 12 cannot be inserted into the fork hole 11a of the object pallet 11A.

[0221]

Mathematical formula 1

[0222]

[0223] When the controller 30D determines that the roll angle of the forklift 1 relative to the pickup object pallet 11A is less than the first predetermined angle θx, the controller 30D determines whether the pitch angle of the forklift 1 relative to the pickup object pallet 11A is less than the predetermined second predetermined angle θy based on the posture of the pickup object pallet 11A relative to the forklift 1 (step S162). In other words, the controller 30D determines whether the second condition that the pitch angle of the forklift 1 relative to the pickup object pallet 11A is less than the predetermined second predetermined angle θy is satisfied.

[0224] The second predetermined angle θy is an angle at which the fork 12 inserted into the fork hole 11a of the pickup target pallet 11A does not interfere with the inner wall surface of the pickup target pallet 11A when the forklift 1 is tilted about the Y axis relative to the pickup target pallet 11A (see Fig. 22 (c)).

[0225] Specifically, if Fig.23 As shown, when the thickness of the fork 12 is set to Fh, the height of the fork hole 11a of the object pallet 11A is set to Ph, and the depth length of the fork hole 11a is set to Pd, when the pitch angle of the forklift 1 relative to the object pallet 11A represented by the following formula is greater than the second specified angle θy, the fork 12 inserted into the fork hole 11a of the object pallet 11A interferes with the inner wall surface of the object pallet 11A.

[0226]

Mathematical formula 2

[0227]

[0228] When the controller 30D determines that the pitch angle of the forklift 1 relative to the pickup object pallet 11A is less than the second predetermined angle θy, the controller 30D determines whether the lateral offset amount of the fork 12 relative to the pickup object pallet 11A is less than a predetermined predetermined amount J based on the position of the pickup object pallet 11A relative to the forklift 1 (step S163). In other words, the controller 30D determines whether the third condition that the lateral offset amount of the forklift 1 relative to the pickup object pallet 11A is less than the predetermined predetermined amount J is satisfied.

[0229] The predetermined amount J is a value that does not exceed the maximum lateral displacement of the fork 12 by the side shift cylinder 15. When the center position of the pickup target pallet 11A exceeds the maximum lateral displacement of the fork 12 by the side shift cylinder 15, the lateral displacement of the fork 12 relative to the pickup target pallet 11A becomes greater than the predetermined amount J (see Fig. 22 (a)).

[0230] When the controller 30D determines that the lateral offset amount of the fork 12 relative to the pickup target pallet 11A is less than the specified amount J, the controller 30D determines whether the yaw angle of the fork 12 relative to the pickup target pallet 11A is less than a predetermined third specified angle θz based on the posture of the pickup target pallet 11A relative to the forklift 1 (step S164). In other words, the controller 30D determines whether the fourth condition that the yaw angle of the forklift 1 relative to the pickup target pallet 11A is less than the predetermined third specified angle θz is satisfied.

[0231] The third predetermined angle θz is an angle at which the fork 12 inserted into the fork hole 11a of the pickup target pallet 11A does not interfere with the inner wall surface of the pickup target pallet 11A when the forklift 1 is tilted about the Z axis relative to the pickup target pallet 11A (see Fig. 22 (d)).

[0232] Specifically, if Fig.23 As shown, when the width of the fork 12 is set to Fw, the width of the fork hole 11a of the object pallet 11A is set to Pw, and the depth length of the fork hole 11a is set to Pd, when the yaw angle of the forklift 1 relative to the object pallet 11A is greater than the third specified angle θz as represented by the following formula, the fork 12 inserted into the fork hole 11a of the object pallet 11A interferes with the inner wall surface of the object pallet 11A.

[0233]

Mathematical formula 3

[0234]

[0235] When the controller 30D determines that the yaw angle of the fork 12 relative to the pickup target pallet 11A is less than or equal to the third predetermined angle θz, it determines that the forklift 1 has successfully approached the cargo loading and unloading position P (step S165). Then, the controller 30D executes Fig.19 Step S112.

[0236] When the controller 30D determines in step S163 that the lateral offset of the fork 12 relative to the object pallet 11A for picking up the cargo is greater than the specified amount J, or when it determines in step S164 that the yaw angle of the fork 12 relative to the object pallet 11A for picking up the cargo is greater than the third specified angle θz, it determines that the forklift 1 has failed to approach the cargo loading and unloading position P (step S166).

[0237] Then, the controller 30D determines that the forklift 1 approaches the cargo loading and unloading position P again (retry) and the cargo pickup of the cargo pickup target pallet 11A is likely to succeed (step S167). Then, the controller 30D executes Fig.19 Step S114.

[0238] When the controller 30D determines in step S161 that the roll angle of the forklift 1 relative to the object pallet 11A for picking up cargo is greater than the first specified angle θx, or when it determines in step S162 that the pitch angle of the forklift 1 relative to the object pallet 11A for picking up cargo is greater than the second specified angle θy, it determines that the forklift 1 has failed to approach the cargo loading and unloading position P (step S168).

[0239] Then, the controller 30D determines that even if the forklift 1 approaches the cargo loading and unloading position P again (retry), it is impossible to successfully pick up the cargo from the target pallet 11A (step S169). Then, the controller 30D executes Fig.19 Step S132 (described later).

[0240] Here, Fig.19 Step S111 is equivalent to steps S161 to S166 and S168. Fig.19 Step S131 is equivalent to steps S161 to S164, S167, and S169.

[0241] Return to Fig.19 When the controller 30D determines in step S131 that the forklift 1 approaches the cargo loading and unloading position P again and the cargo to be picked up from the cargo pallet 11A is likely to be successfully picked up, steps S114 to S122 are executed. The details of step S122 are the same as those of step S111 described above.

[0242] When the controller 30D determines in step S131 that the forklift 1 cannot successfully pick up the target pallet 11A even if the forklift 1 approaches the cargo loading and unloading position P again, the controller 30D controls the travel drive unit 24 to stop the travel of the forklift 1 abnormally (step S132). Then, the controller 30D executes step S123.

[0243] When the controller 30D determines in step S122 that the forklift 1 has failed to re-approach the cargo loading and unloading position P, it determines whether the number of times the forklift 1 has re-approached the cargo loading and unloading position P (number of retries) has reached a predetermined upper limit (step S133). The upper limit may be 1 time, or may be multiple times, as in the first embodiment described above. When the controller 30D determines that the number of times the forklift 1 has re-approached the cargo loading and unloading position P has not reached the upper limit, it executes the above step S114 again.

[0244] When the controller 30D determines that the number of times the forklift 1 has approached the cargo loading and unloading position P has reached the upper limit, the controller 30D controls the travel drive unit 24 to stop the travel of the forklift 1 abnormally (step S132). Then, the controller 30D executes step S123.

[0245] Here, the pallet position calculation unit 31 executes steps S101, S102, S109, S110, S120, and S121. The own position estimation unit 32 executes steps S103, S106, S114, and S117. The route generation unit 33 executes step S104. The guidance control unit 34 executes steps S105, S107, and S108. The approach determination unit 35D executes step S111. The pickup availability determination unit 45 executes step S131. The route regeneration unit 36D executes step S115. The re-guidance control unit 37D executes steps S116, S118, and S119. The re-approach determination unit 38D executes step S122. The re-approach count determination unit 46 executes step S133. The cargo handling control unit 39D executes steps S112 and S113. The abnormal stop control unit 47 executes step S132. The alarm control unit 40 executes step S123.

[0246] Furthermore, when the success rate of picking up goods becomes higher, the number of abnormal handling times can be reduced and the cycle time of picking up goods can be shortened by retrying the forklift 1 to approach the cargo loading and unloading position P. However, when the forklift 1 is retried to approach the cargo loading and unloading position P despite the low success rate of picking up goods, the abnormal handling response will delay the time of retrying the approach of the forklift 1 compared to the case where the forklift 1 is stopped immediately due to the abnormal driving, and thus the cycle time of picking up goods is increased as a result.

[0247] Therefore, in the present embodiment, when it is determined that the forklift 1 has failed to approach the cargo loading and unloading position P, it is determined whether it is possible to successfully pick up the cargo pallet 11A by the forklift 1 approaching the cargo loading and unloading position P again. Furthermore, when it is determined that it is impossible to successfully pick up the cargo pallet 11A even if the forklift 1 approaches the cargo loading and unloading position P again, the forklift 1 is stopped due to abnormal driving, and there is no need to retry the approach of the forklift 1 in vain. Therefore, the total abnormality handling time and cargo loading and unloading time can be reduced.

[0248] In this embodiment, when the position or posture of the pickup target pallet 11A relative to the forklift 1 is offset by a certain amount or more, it is determined that the forklift 1 has failed to approach the cargo loading and unloading position P. Therefore, the success or failure of the forklift 1 approaching the cargo loading and unloading position P can be appropriately determined.

[0249] In addition, in the present embodiment, when, for example, the roll angle of the forklift 1 relative to the object pallet 11A exceeds the first specified angle θx due to the tilt of the object pallet 11A, or the pitch angle of the forklift 1 relative to the object pallet 11A exceeds the second specified angle θy, there is no need to perform a futile retry of the forklift 1 to approach.

[0250] In addition, in the present embodiment, when the forklift 1 fails to approach the cargo loading and unloading position P again, the forklift 1 is retried to approach the cargo loading and unloading position P, and the probability of the forklift 1 reaching the appropriate cargo loading and unloading position P corresponding to the position of the pickup target pallet 11A becomes higher. As a result, the success rate of picking up cargo by the forklift 1 is further improved.

[0251] In addition, in the present embodiment, when the number of retries of the forklift 1 approaching the cargo handling position P reaches the upper limit, the forklift 1 is stopped due to abnormal travel, so that the forklift 1 does not need to retry approaching more than necessary. Therefore, the total abnormality handling time and cargo handling time can be further reduced.

[0252] In the present embodiment, the process corresponding to the controller 30 of the first embodiment described above is executed, but the process corresponding to the controllers 30A to 30C of the second to fourth embodiments described above may be executed.

[0253] Several embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in the above second to fourth embodiments, when the forklift 1 fails to approach the cargo loading and unloading position P, the forklift 1 is temporarily retreated from the cargo loading and unloading position P to the starting position P0, but the present invention is not particularly limited to this method, and it is sufficient as long as the forklift 1 is temporarily retreated to a position away from the cargo loading and unloading position P.

[0254] In the above embodiment, the cargo pallet 11 loaded on the cargo bed 18 of the truck 17 is picked up, but the present invention is not limited to this method. For example, the cargo pallet 11 loaded on the truck berth or designated ground may be picked up.

[0255] In the above embodiment, the pallet 11 is picked up, but cargo loading and unloading is not limited to picking up cargo, and so-called cargo placement such as placing the pallet 11 held by the forks 12 of the forklift 1 on the cargo platform 18 of the truck 17 may be performed.

[0256] In addition, in the above-mentioned embodiment, the position and posture of the pickup object pallet 11A relative to the forklift 1 are calculated based on the shooting data of the camera 21 or the side camera 51 and the front camera 52, but it is not particularly limited to this method, and only the position of the pickup object pallet 11A relative to the forklift 1 can also be calculated.

[0257] In addition, in the above-mentioned embodiment, the pickup object pallet 11A is detected by the camera 21 or the side camera 51 and the front camera 52, but the object detection unit for detecting the object of cargo loading and unloading is not particularly limited to the camera, and laser sensors, ultrasonic sensors, optical sensors, etc. can also be used.

[0258] In the above embodiment, the forklift 1 is a reach forklift, but the forklift 1 may be a counter forklift. In this case, when picking up goods, the forklift 1 is driven forward to insert the fork 12 into the fork hole 11a of the pallet 11A to be picked up.

[0259] Furthermore, in the above-described embodiment, the forklift 1 includes the side shift cylinder 15 , but the present invention can also be applied to a forklift that does not include the side shift cylinder 15 .

Claims

1. A cargo handling control device, which is a cargo handling control device for moving a forklift from a starting position toward a cargo handling object to load and unload cargo, characterized in that: have: an object detection unit, which detects the cargo loading and unloading object; a position calculating unit that calculates a position of the cargo handling object relative to the forklift based on the detection data of the object detecting unit; an approach control unit that controls the forklift to approach a cargo handling position corresponding to the cargo handling object based on the position of the cargo handling object relative to the forklift calculated by the position calculation unit when the forklift is at the starting position; an approach determination unit that determines whether the forklift has successfully approached the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift arrives at the cargo loading and unloading position; a cargo handling control unit that controls the forklift to load or unload cargo on the cargo handling object when the approach determination unit determines that the forklift has successfully approached the cargo handling position; as well as a re-approach control unit that controls the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the approach determination unit determines that the forklift has failed to approach the cargo loading and unloading position.

2. The cargo handling control device according to claim 1, wherein: When it is determined that the forklift has failed to approach the cargo loading and unloading position, the re-approach control unit controls the forklift to re-approach the cargo loading and unloading position after temporarily retreating from the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift was at the cargo loading and unloading position.

3. The cargo handling control device according to claim 1, wherein: When it is determined that the forklift has failed to approach the cargo loading and unloading position, the re-approach control unit controls the forklift to temporarily retreat relative to the cargo loading and unloading position, and then controls the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit.

4. The cargo handling control device according to claim 3, wherein: The re-approach control unit controls the forklift to temporarily retreat to the starting position relative to the cargo loading and unloading position, and then controls the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is at the starting position.

5. The cargo handling control device according to claim 1, wherein: The method further comprises a detection possibility determination unit for determining whether the object detection unit can detect the cargo loading and unloading object at the cargo loading and unloading position when the approach determination unit determines that the forklift fails to approach the cargo loading and unloading position. When the detection possibility determination unit determines that the object detection unit can detect the cargo loading and unloading object at the cargo loading and unloading position, the re-approach control unit controls the forklift to temporarily retreat from the cargo loading and unloading position and then approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is at the cargo loading and unloading position. When the detection possibility determination unit determines that the object detection unit cannot detect the cargo loading and unloading object at the cargo loading and unloading position, the re-approach control unit controls the forklift to temporarily retreat from the cargo loading and unloading position and then controls the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit.

6. The cargo handling control device according to claim 5, wherein: When it is determined that the object detection unit cannot detect the cargo loading and unloading object, the re-approach control unit controls the forklift to temporarily retreat to the starting position relative to the cargo loading and unloading position, and then controls the forklift to approach the cargo loading and unloading position again based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is at the starting position.

7. The cargo handling control device according to claim 1, wherein: The forklift has a side shift cylinder for moving the fork in the left-right direction of the forklift. The approach determination unit determines whether a lateral offset amount of the forklift relative to the cargo loading and unloading object is less than a predetermined amount based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift is at the cargo loading and unloading position, and determines that the forklift has successfully approached the cargo loading and unloading position when the lateral offset amount of the forklift relative to the cargo loading and unloading object is less than the predetermined amount, and determines that the forklift has failed to approach the cargo loading and unloading position when the lateral offset amount of the forklift relative to the cargo loading and unloading object is not less than the predetermined amount.

8. The cargo handling control device according to claim 1, wherein: Also available: a re-approach determination unit that determines whether the forklift has successfully re-approached the cargo loading and unloading position based on the position of the cargo loading and unloading object relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position again; as well as a notification unit configured to issue an abnormality notification when the re-approach determination unit determines that the forklift fails to re-approach the cargo loading and unloading position, The cargo handling control unit controls the forklift to load or unload cargo on the cargo handling target when the re-approach determination unit determines that the forklift has successfully re-approached the cargo handling position.

9. The cargo handling control device according to claim 1, wherein: The object detection unit detects the cargo handling object in a state where the forklift faces forward with respect to the cargo handling object.

10. The cargo handling control device according to claim 1, wherein: The object detection unit includes: a first detection unit that detects the cargo loading and unloading object when the forklift is facing sideways relative to the cargo loading and unloading object; and a second detection unit that detects the cargo loading and unloading object when the forklift is facing frontally relative to the cargo loading and unloading object. The position calculation unit calculates the position of the cargo loading and unloading object relative to the forklift based on the detection data of the first detection unit when the forklift is at the starting position, and calculates the position of the cargo loading and unloading object relative to the forklift based on the detection data of the second detection unit when the forklift is at the cargo loading and unloading position.

11. The cargo handling control device according to claim 1, wherein: The cargo loading and unloading object is a pallet having a pair of fork holes for inserting a pair of left and right forks of the forklift. The position calculation unit calculates the position and posture of the pallet relative to the forklift based on the detection data of the object detection unit. The approach control unit controls the forklift to approach a cargo loading and unloading position corresponding to the position of the pallet based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift is at the starting position, The approach determination unit determines whether the forklift has successfully approached the cargo loading and unloading position based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift arrives at the cargo loading and unloading position. The cargo handling control unit controls the forklift to pick up cargo from the pallet as the cargo handling when the approach determination unit determines that the forklift has successfully approached the cargo handling position. When the approach determination unit determines that the forklift has failed to approach the cargo loading and unloading position, the re-approach control unit controls the forklift to approach the cargo loading and unloading position again based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit.

12. The cargo handling control device according to claim 11, wherein: Also available: a cargo pickup determination unit for determining whether it is possible to successfully pick up the cargo pallet by the forklift approaching the cargo loading and unloading position again based on the position and posture of the cargo pallet relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position, when the approach determination unit determines that the forklift has failed to approach the cargo loading and unloading position; as well as an abnormal stop control unit for controlling the forklift to stop abnormally when the pickup determination unit determines that it is impossible to successfully pick up the cargo pallet even if the forklift approaches the cargo loading and unloading position again, When the pickup feasibility determination unit determines that there is a possibility that the forklift can successfully pick up the pallet by approaching the cargo loading and unloading position again, the re-approach control unit controls the forklift to approach the cargo loading and unloading position again based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit.

13. The cargo handling control device according to claim 12, wherein: The forklift includes a side shift cylinder for moving the fork in the left-right direction of the forklift. The approach determination unit determines whether a first condition that a roll angle of the forklift relative to the pallet is less than a predetermined first specified angle, a second condition that a pitch angle of the forklift relative to the pallet is less than a predetermined second specified angle, a third condition that a lateral offset amount of the forklift relative to the pallet is less than a predetermined specified amount, and a fourth condition that a yaw angle of the forklift relative to the pallet is less than a predetermined third specified angle are satisfied, and when all of the first condition, the second condition, the third condition, and the fourth condition are satisfied, it is determined that the forklift has successfully approached the cargo loading and unloading position, and when any one of the first condition, the second condition, the third condition, and the fourth condition is not satisfied, it is determined that the forklift has failed to approach the cargo loading and unloading position.

14. The cargo handling control device according to claim 13, wherein: The pickup feasibility determination unit determines that it is possible to successfully pick up the pallet by the forklift approaching the cargo loading and unloading position again when the first condition and the second condition are satisfied, and determines that it is impossible to successfully pick up the pallet even if the forklift approaches the cargo loading and unloading position again when either the first condition or the second condition is not satisfied.

15. The cargo handling control device according to claim 11, wherein: The method further comprises a re-approach determination unit for determining whether the forklift has successfully re-approached the cargo loading and unloading position based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the forklift reaches the cargo loading and unloading position again. The re-approach control unit controls the forklift to approach the cargo loading and unloading position again based on the position and posture of the pallet relative to the forklift calculated by the position calculation unit when the re-approach determination unit determines that the forklift has failed to re-approach the cargo loading and unloading position. The cargo loading and unloading control unit controls the forklift to pick up cargo from the pallet when the re-approach determination unit determines that the forklift has successfully re-approached the cargo loading and unloading position.

16. The cargo handling control device according to claim 15, wherein: Also available: a re-approach frequency determination unit for determining whether the number of re-approaches of the forklift to the cargo loading and unloading position has reached a predetermined upper limit value when the re-approach determination unit determines that the forklift has failed to re-approach the cargo loading and unloading position; as well as The abnormal stop control unit controls the forklift to stop abnormally when the re-approach frequency determination unit determines that the number of times the forklift has re-approached the cargo loading and unloading position has reached the upper limit value.

Images