Automated guided vehicle

Abstract

To provide an unmanned conveyance vehicle capable of controlling a tilting angle of a mast by simple processing.SOLUTION: An unmanned conveyance vehicle includes a cargo handling device having a mast, a fork mounted on the mast, and a tilt cylinder 15 for tilting the mast and a control unit 30 for controlling the posture of the mast. The control device 30 includes a detection unit 34 for detecting the weight of a load held at a fixed position of the fork, an estimation unit 35 for referring to data showing a relationship between the weight of the load at the fixed position and an estimated value of a deflection angle of the fork based on the weight of the load detected by the detection unit 34 to estimate the deflection angle of the fork, a calculation unit 37 for calculating a correction amount of a tilting angle of the mast so as to make the fork horizontal based on the estimated value, and a control unit 38 for controlling the tilting angle of the mast by the tilt cylinder 15 based on the correction amount.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to automated guided vehicles. [Background technology]

[0002] An example of a conventional automated guided vehicle is the automated guided vehicle described in Patent Document 1. This conventional automated guided vehicle is equipped with a loading device having a mast and forks attached to the mast. This conventional automated guided vehicle calculates the center of gravity of the load, calculates the moment acting on the forks from the calculated center of gravity of the load, and calculates the deflection angle of the forks from the moment. Furthermore, this conventional automated guided vehicle uses the calculated deflection angle of the forks to control the tilt angle of the mast so that the forks are horizontal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-189410 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method described in Patent Document 1, the center of gravity of the load and the moment acting on the fork by the load must be calculated in order to control the tilting angle of the mast, which may complicate the processing.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide an unmanned guided vehicle that can control the tilt angle of the mast with a simple process. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, an automated guided vehicle includes a loading device having a mast, forks attached to the mast, and a tilt cylinder for tilting the mast, and a control device for controlling the attitude of the mast. The control device includes a detection unit that detects the weight of a load held in a fixed position of the forks, an estimation unit that estimates the deflection angle of the forks by referencing data indicating a relationship between the weight of the load at the fixed position and an estimated value of the deflection angle of the forks based on the weight of the load detected by the detection unit, a calculation unit that calculates a correction amount for the tilt angle of the mast to level the forks based on the estimated value, and a control unit that controls the tilt angle of the mast using the tilt cylinder based on the correction amount.

[0007] In this automated guided vehicle, taking into account the tendency for the forks to hold a load in a fixed position, the fork deflection angle is estimated by referencing data showing the relationship between the weight of the load at the fixed fork position and the estimated value of the fork deflection angle.The mast tilt angle is then controlled based on a correction amount calculated based on the estimated value of the fork deflection angle.In this automated guided vehicle, estimating the fork deflection angle based on the weight of the load at the fixed fork position eliminates the need to calculate the center of gravity of the load and the moment acting on the fork by the load, allowing the mast tilt angle to be controlled with simple processing.

[0008] The control device may further include an acquisition unit that acquires images of the luggage and a discrimination unit that discriminates the category of the luggage based on the images. The data may include a plurality of categorized data corresponding to the luggage categories. The estimation unit may select categorized data to be used for estimating the bending angle of the forks from the plurality of categorized data based on the luggage category discriminated by the discrimination unit. In this case, an estimated value of the bending angle of the forks relative to the weight of the luggage can be calculated for each luggage category. Therefore, the bending angle of the forks can be estimated with high accuracy.

[0009] The control device may further include a confirmation unit that confirms whether the load is being held in the fixed position of the forks, thereby preventing a discrepancy between the estimated value of the fork deflection angle obtained from the data and the actual fork deflection angle due to the weight of the load.

[0010] The control unit may control the tilt angle of the mast using the tilt cylinder so that the mast is vertical before the detection unit detects the weight of the load. By aligning the mast to be vertical when detecting the weight of the load, it is possible to more reliably prevent a discrepancy between the estimated value of the fork deflection angle obtained from the data and the actual fork deflection angle due to the weight of the load. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide an automated guided vehicle that can control the tilt angle of the mast with a simple process. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a side view illustrating an example of an automated guided vehicle according to the present disclosure. [Figure 2] 10A and 10B are diagrams illustrating the configuration of a load and forks when an automatic guided vehicle holds the load. [Figure 3] FIG. 2 is a block diagram showing the functional configuration of a control device. [Figure 4] FIG. 10 is a diagram showing an example of data showing the relationship between the weight of a load in a fixed position and an estimated value of the deflection angle of the fork. [Figure 5] 10A and 10B are diagrams illustrating the configuration of the luggage and forks after the control device has controlled the attitude of the mast. [Figure 6] 4 is a flowchart showing an example of the operation of the control device. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, preferred embodiments of an automated guided vehicle according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0014] Fig. 1 is a side view showing an example of an automated guided vehicle 1 according to the present disclosure. The automated guided vehicle 1 is configured as an autonomous forklift that receives a load W at a loading position set at any position, for example, indoors or outdoors, and transports the received load W. As shown in Fig. 1, the automated guided vehicle 1 includes a traveling device 2, a loading device 3 arranged in front of the traveling device 2, and a control device 30 (see Fig. 3) that controls the attitude of a mast 11.

[0015] The traveling device 2 has a vehicle body 4, a pair of front wheels 5 which are drive wheels located at the front of the vehicle body 4, and a pair of rear wheels 6 which are steered wheels located at the rear of the vehicle body 4. The vehicle body 4 is provided with a driver's cab 7 which is formed by a frame including a head guard. Inside the driver's cab 7, there are arranged a lift operation lever used to operate the lift cylinder 14, a tilt operation lever used to operate the tilt cylinder 15, a steering wheel for steering the automated guided vehicle 1, and the like. In addition, the traveling device 2 has a traveling motor which rotates the front wheels 5, and a steering motor which turns the rear wheels 6 by rotating the steering shaft of the automated guided vehicle 1. In the automated guided vehicle 1, the traveling motor rotates the front wheels 5, and the steering motor steers the rear wheels 6, thereby achieving automatic traveling by the traveling device 2.

[0016] The cargo handling device 3 has a mast 11 attached to the front of the vehicle body 4, a pair of forks 13 attached to the mast 11 via lift brackets 12 and holding cargo W, a lift cylinder 14 that raises and lowers the forks 13, a tilt cylinder 15 that tilts the mast 11, and a spacer 16 that defines a fixed position P for the forks 13 when holding cargo W. The forks 13 are attached so as to protrude forward from the lift brackets 12. When not holding cargo W, the forks 13 are attached to the lift brackets 12 so as to be perpendicular to the mast 11 (horizontal to the ground), as shown in FIG. 1 .

[0017] In this embodiment, the spacer 16 is, for example, box-shaped, and the back surface of the spacer 16 contacts the base end of the fork 13. The installation position of the spacer 16 is not limited to the above-mentioned position, as long as the loading area of ​​the fork 13 is sufficiently secured for the cargo W. For example, the back surface of the spacer 16 may be spaced apart from the base end of the fork 13. The spacer 16 is formed, for example, from a metal material. This provides the spacer 16 with sufficient strength to prevent deformation due to the cargo W being pushed into it. Examples of metal materials that can be used to form the spacer 16 include aluminum and reinforced plastic.

[0018] As described above, the automated guided vehicle 1 is configured as, for example, an automatically operated forklift, and is operated on the premise that the load W is held at the fixed position P of the forks 13. As described above, the fixed position P when the forks 13 hold the load W is determined by the spacer 16. In this embodiment, the fixed position P is a position on the base end side of the forks 13 and in contact with the front surface of the spacer 16.

[0019] The deflection angle θ1 of the forks 13 when the automated guided vehicle 1 holds a load W will be described with reference to Figure 2. Figure 2 is a diagram showing the configuration of the load W and the forks 13 when the automated guided vehicle 1 holds a load W. As described above, the automated guided vehicle 1 is operated on the premise that the load W is held at a fixed position P of the forks 13, and the load W is held by the forks 13 so that it contacts the front surface of the spacer 16 at the fixed position P.

[0020] When the forks 13 hold a load W at their fixed positions P, the weight of the load W may cause the forks 13 to bend. If the forks 13 bend due to the weight of the load W, as shown in FIG. 2, even if the mast 11 is positioned perpendicular to the ground, the tip ends of the forks 13 may become lower than the base ends, and the forks 13 may tilt at a bending angle θ1 relative to the horizontal. In response to this, the automated guided vehicle 1 is equipped with a control device 30 that controls the attitude of the mast 11 by estimating the bending angle θ1 in order to maintain the load W holding performance against bending of the forks 13. The components for realizing this function will be described in detail below.

[0021] FIG. 3 is a block diagram showing the functional configuration of the control device 30. The control device 30 controls the posture of the mast 11 in consideration of the deflection angle θ1 of the forks 13 due to the weight of the load W described above. The control device 30 is an electronic control unit having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The control device 30 realizes various functions by, for example, loading a program stored in the ROM into the RAM and executing the program loaded into the RAM with the CPU. The control device 30 has, as functional elements, an acquisition unit 31, a determination unit 32, a confirmation unit 33, a detection unit 34, an estimation unit 35, a storage unit 36, a calculation unit 37, and a control unit 38.

[0022] The acquisition unit 31 is a part that acquires an image of the luggage W. In this embodiment, the acquisition unit 31 is connected to the imaging device 20 so as to be able to communicate information. The acquisition unit 31 acquires an image of the luggage W from the imaging device 20 and outputs the acquired image of the luggage W to the discrimination unit 32. The imaging device 20 is a device that captures an image of the luggage W held by the forks 13. In this embodiment, the automatic guided vehicle 1 is equipped with the imaging device 20. In the example shown in FIG. 1, the imaging device 20 is attached to the top of the mast 11. The imaging device 20 may also be attached to the top of the lift bracket 12, for example. The imaging device 20 is configured to include an imaging element such as a CCD camera. The imaging device 20 may be a device that acquires color images or a device that acquires monochrome images.

[0023] The imaging device 20 captures an image of the package W, for example, when the package W is held at the fixed position P of the forks 13, and outputs the image of the package W to the acquisition unit 31. In this case, a confirmation unit 33 (described later) may output information indicating that the package W is being held at the fixed position P of the forks 13 to the imaging device 20, which may serve as a trigger for capturing an image of the package W. The imaging device 20 may capture an image of the package W before the package W is held at the fixed position P of the forks 13. In this case, the approach of the package W to the automatic guided vehicle 1 may be detected by, for example, an optical sensor, and the detection may serve as a trigger for capturing an image of the package W.

[0024] The discrimination unit 32 is a part that discriminates the category of the luggage W. The discrimination unit 32 discriminates the category of the luggage W based on the image of the luggage W received from the acquisition unit 31. The category of the luggage W refers to a classification based on the height position or front-to-back position of the center of gravity of the luggage W, rather than a classification based on the contents of the luggage W. The discrimination unit 32 does not perform a calculation to estimate the center of gravity position of the luggage W, but rather the center of gravity position of the luggage W is roughly categorized in advance based on the size of the luggage (the size of the container or box). In this embodiment, the categories of the luggage W are divided into three categories depending on the size of the luggage W. The discrimination unit 32 analyzes the image of the luggage W received from the acquisition unit 31 and discriminates the category of the luggage W based on the size of the luggage W. The discrimination unit 32 outputs information indicating the discrimination result of the category of the luggage W to the confirmation unit 33.

[0025] The confirmation unit 33 is a part that confirms whether the luggage W is being held at the fixed position P of the forks 13. When the confirmation unit 33 receives information indicating the result of the classification of the category of the luggage W from the classification unit 32, it waits for detection information from the limit switch 17. As shown in FIG. 1 , the limit switch 17 is provided on the front surface of the spacer 16. In this embodiment, the limit switch 17 is a contact-type limit switch and is a component of the cargo handling device 3. When the forks 13 are not holding the luggage W at the fixed position P, the limit switch 17 protrudes forward from the front surface of the spacer 16.

[0026] When the forks 13 are holding the luggage W at the fixed position P, the luggage W pushes the limit switch 17 toward the spacer 16, and detection information indicating that the luggage W is being held at the fixed position P is output from the limit switch 17 to the confirmation unit 33. Upon receiving the detection information, the confirmation unit 33 confirms that the luggage W is being held at the fixed position P and outputs the detection information to the detection unit 34. Note that if the confirmation unit 33 does not receive a detection signal from the limit switch 17 within a certain period of time after receiving information indicating the classification result of the luggage W from the classification unit 32, it may issue warning information indicating this to the outside. In this case, it is possible to prevent the luggage W from being held by the forks 13 in a state deviated from the fixed position P.

[0027] The detection unit 34 is a part that detects the weight of the luggage W. Upon receiving detection information from the confirmation unit 33, the detection unit 34 detects the weight of the luggage W. In this embodiment, the detection unit 34 holds data indicating the relationship between the pressure of the lift cylinder 14 and the weight of the luggage W, for example, when the mast 11 is perpendicular to the ground. The detection unit 34 acquires the pressure of the lift cylinder 14 upon receiving a detection signal from the confirmation unit 33, and detects the weight of the luggage W by referring to the data based on the acquired pressure. The detection unit 34 outputs information indicating the detection result of the weight of the luggage W to the estimation unit 35, together with information indicating the classification result of the category of the luggage W.

[0028] The estimation unit 35 is a part that estimates the bending angle θ1 of the forks 13. When the estimation unit 35 receives information indicating the detection result of the weight of the luggage W from the detection unit 34, the estimation unit 35 refers to data indicating the relationship between the weight of the luggage W at the home position P and the estimated value of the bending angle θ1 of the forks 13, and obtains the estimated value of the bending angle θ1 of the forks 13. The estimation unit 35 outputs information indicating the estimated result of the bending angle θ1 to the calculation unit 37.

[0029] 4 is a diagram showing an example of data d indicating the relationship between the weight of the luggage W at the fixed position P and the estimated value of the bending angle θ1 of the forks 13. In the example shown in FIG. 4, the data d indicating the relationship between the weight of the luggage W at the fixed position P and the estimated value of the bending angle θ1 of the forks 13 includes multiple categorized data corresponding to categories of luggage W. Here, the data d includes three categorized data d1, d2, and d3 corresponding to three categories of luggage W. In the example shown in FIG. 4, in all of the categorized data d1, d2, and d3, the relationship between the weight of the luggage W and the estimated value of the bending angle θ1 is linear, and the estimated value of the bending angle θ1 increases as the weight of the luggage W increases.

[0030] The estimation unit 35 identifies the category of the luggage W based on the information indicating the result of the classification of the category of the luggage W, and selects, from the category data d1, d2, and d3, category data to be used for estimating the bending angle θ1 of the forks 13. Next, the estimation unit 35 refers to the category data selected based on the information indicating the detection result of the weight of the luggage W, and obtains an estimated value of the bending angle θ1 of the forks 13.

[0031] In this embodiment, data d including multiple categorized data d1, d2, and d3 is stored in the storage unit 36. The data d is generated by actually measuring the amount of deflection of the fork 13 while changing the weight of the load under the conditions that the automated guided vehicle 1 holds the load at a fixed position P and the mast 11 is vertical, and is stored in advance in the storage unit 36.

[0032] The calculation unit 37 is a part that calculates the correction amount for the tilt angle θ2 of the mast 11. When the calculation unit 37 receives information indicating the estimated result of the deflection angle θ1 from the estimating unit 35, the calculation unit 37 calculates the correction amount for the tilt angle θ2 of the mast 11 (see FIG. 5) to make the fork 13 horizontal, based on the information. In this embodiment, the calculation unit 37 calculates the difference between the estimated value of the deflection angle θ1 of the fork 13 and the angle when the fork 13 is horizontal as the correction amount for the tilt angle θ2 of the mast 11. The calculation unit 37 may also calculate the difference between the estimated value of the deflection angle θ1 of the fork 13 and the angle when the fork 13 is horizontal by a predetermined coefficient as the correction amount for the tilt angle θ2 of the mast 11. The calculation unit 37 outputs the calculated correction amount to the control unit 38.

[0033] The control unit 38 is a part that controls the tilt angle θ2 of the mast 11. In one example, the control unit 38 controls the tilt angle θ2 of the mast 11 using the tilt cylinder 15 based on the correction amount received from the calculation unit 37. In this embodiment, as shown in FIG. 5 , the control unit 38 tilts the mast 11 rearward based on the correction amount received from the calculation unit 37. As a result, the forks 13, which have been bent so that their tip ends are lower than their base ends due to the weight of the cargo W, rotate together with the mast 11, and the cargo W is held horizontally at the home position P of the forks 13.

[0034] An example of the operation of the control device 30 will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the operation of the control device 30.

[0035] In step S1, an image of the luggage W is acquired. In step S2, the discrimination unit 32 discriminates the category of the luggage W based on the image of the luggage W. In step S3, it is confirmed whether the luggage W is being held at the fixed position P of the forks 13. If the luggage W is not being held at the fixed position P, a warning to that effect may be issued. In step S4, the tilt angle θ2 of the mast 11 is controlled so that the mast 11 is vertical. In step S5, the detection unit 34 detects the weight of the luggage W when the mast 11 is vertical. Here, the weight of the luggage W is detected based on the pressure of the lift cylinder 14, for example.

[0036] In step S6, the bending angle θ1 of the forks 13 is estimated. Here, based on the category of the luggage W determined in step S2, category data to be used for estimating the bending angle θ1 of the forks 13 is selected from the multiple category data d1, d2, d3. Next, the bending angle θ1 of the forks 13 is estimated by referring to the category data selected based on the weight of the luggage W detected in step S5.

[0037] In step S7, the calculation unit 37 calculates the amount of correction for the tilt angle θ2 of the mast 11. Here, the difference between the estimated value of the deflection angle θ1 of the forks 13 estimated in step S6 and the angle when the forks 13 are horizontal is calculated as the amount of correction for the tilt angle θ2 of the mast 11. In step S8, the control unit 38 controls the tilt angle θ2 of the mast 11. Here, the tilt cylinder 15 controls the tilt angle θ2 of the mast 11 based on the amount of correction for the tilt angle θ2 of the mast 11 calculated in step S7. By tilting the mast 11 backward based on this tilt angle θ2, the load W is held horizontally at the home position P of the forks 13.

[0038] As described above, in the automated guided vehicle 1, in view of the tendency for the load W to be held at the home position P of the forks 13, the deflection angle θ1 of the forks 13 is estimated by referencing data d that indicates the relationship between the weight of the load W at the home position P of the forks 13 and the estimated value of the deflection angle θ1 of the forks 13. The tilt angle θ2 of the mast 11 is then controlled based on a correction amount calculated based on the estimated value of the deflection angle θ1 of the forks 13. In the automated guided vehicle 1, estimating the deflection angle θ1 of the forks 13 based on the weight of the load W at the home position P of the forks 13 eliminates the need to calculate the center of gravity of the load W and the moment acting on the forks 13 due to the load W, and therefore the tilt angle θ2 of the mast 11 can be controlled with simple processing.

[0039] In the automated guided vehicle 1, the control device 30 includes an acquisition unit 31 that acquires an image of the luggage W and a discrimination unit 32 that discriminates the category of the luggage W based on the image. The data d includes multiple category-specific data d1, d2, and d3 corresponding to the category of the luggage W. The estimation unit 35 selects category-specific data to be used for estimating the deflection angle θ1 of the forks 13 from the multiple category-specific data d1, d2, and d3 based on the category of the luggage W discriminated by the discrimination unit 32. In this case, an estimated value of the deflection angle θ1 of the forks 13 relative to the weight of the luggage W can be calculated for each category of luggage W. Therefore, the deflection angle θ1 of the forks 13 can be accurately estimated.

[0040] In the automated guided vehicle 1, the control device 30 has a confirmation unit 33 that confirms whether the load W is being held at the fixed position P of the forks 13. This makes it possible to prevent a discrepancy from occurring between the estimated value of the deflection angle θ1 of the forks 13 obtained from the data d and the actual deflection angle θ1 of the forks 13 due to the weight of the load W.

[0041] In the automated guided vehicle 1, the control unit 38 controls the tilt angle θ2 of the mast 11 using the tilt cylinder 15 so that the mast 11 is vertical before the detection unit 34 detects the weight of the luggage W. By aligning the posture of the mast 11 to be vertical when detecting the weight of the luggage W, it is possible to more reliably prevent a discrepancy from occurring between the estimated value of the deflection angle θ1 of the forks 13 obtained from the data d and the actual deflection angle θ1 of the forks 13 due to the weight of the luggage W.

[0042] Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0043] For example, the automated guided vehicle 1 does not necessarily have to be equipped with the imaging device 20. In this case, for example, an image of the luggage W may be acquired from a fixed camera installed in the travel area of ​​the automated guided vehicle 1 and used to determine the category of the luggage W. Also, for example, the control device 30 does not necessarily have the holding unit 36. In this case, data d indicating the relationship between the weight of the luggage W at the home position P of the forks 13 and the estimated value of the deflection angle θ1 of the forks 13 may be stored in an external server different from the control device 30. By receiving the data d from the external server via a predetermined communication network, the estimation unit 35 can acquire the estimated value of the deflection angle θ1.

[0044] The gist of this disclosure is as follows [1] to [4]. [1] An unmanned transport vehicle comprising: a loading device having a mast, forks attached to the mast, and a tilt cylinder for tilting the mast; and a control device for controlling the attitude of the mast, wherein the control device comprises: a detection unit for detecting the weight of a load held at a fixed position of the forks; an estimation unit for estimating the deflection angle of the forks by referring to data showing the relationship between the weight of the load at the fixed position and an estimated value of the deflection angle of the forks based on the weight of the load detected by the detection unit; a calculation unit for calculating a correction amount for the tilt angle of the mast to level the forks based on the estimated value; and a control unit for controlling the tilt angle of the mast using the tilt cylinder based on the correction amount. [2] The control device further includes an acquisition unit that acquires an image of the luggage and a discrimination unit that discriminates the category of the luggage based on the image, the data includes a plurality of categorized data corresponding to the category of the luggage, and the estimation unit selects, from the plurality of categorized data, the categorized data to be used for estimating the deflection angle of the fork, based on the category of the luggage discriminated by the discrimination unit. [1] The unmanned guided vehicle described in [1]. [3] The unmanned transport vehicle according to [1] or [2], wherein the control device further has a confirmation unit that confirms whether the load is held at the fixed position of the fork. [4] An unmanned guided vehicle according to any one of [1] to [3], wherein the control unit controls the tilt angle of the mast using the tilt cylinder so that the mast is vertical before the detection unit detects the weight of the luggage. [Explanation of symbols]

[0045] 1...automated guided vehicle, 3...load handling device, 11...mast, 13...fork, 15...tilt cylinder, 30...control device, 31...acquisition unit, 32...discrimination unit, 33...confirmation unit, 34...detection unit, 35...estimation unit, 37...calculation unit, 38...control unit, d...data, d1, d2, d3...categorical data, P...fixed position, W...baggage, θ1...deflection angle, θ2...tilt angle.

Claims

1. a cargo handling device including a mast, a fork attached to the mast, and a tilt cylinder for tilting the mast; a control device for controlling the attitude of the mast, The control device a detection unit for detecting the weight of a load held at a fixed position on the forks; an estimation unit that estimates a bending angle of the forks by referring to data indicating a relationship between the weight of the luggage at the fixed position and an estimated value of the bending angle of the forks based on the weight of the luggage detected by the detection unit; a calculation unit that calculates a correction amount for the tilt angle of the mast to make the fork horizontal based on the estimated value; and a control unit that controls the tilt angle of the mast by the tilt cylinder based on the correction amount; an acquisition unit that acquires an image of the package; a discrimination unit that discriminates the category of the luggage based on the image, the data includes a plurality of category data corresponding to categories of the luggage; The estimation unit selects, from the plurality of categorized data, categorized data to be used for estimating the deflection angle of the fork, based on the category of the cargo determined by the determination unit.

2. 2. The automated guided vehicle according to claim 1, wherein the control device further comprises a confirmation unit that confirms whether the load is held at the fixed position on the forks.

3. 3. The automated guided vehicle according to claim 1, wherein the control unit controls the tilt angle of the mast by the tilt cylinder so that the mast is vertical before the detection unit detects the weight of the load.

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