Work vehicle

Abstract

This work vehicle comprises a visual recognition unit having an imaging function and a distance detection function, and a control unit that controls a crane device. The control unit calculates the estimated weight of a suspended load on the basis of information relating to an image of the suspended load that has been captured by the visual recognition unit and the distance to the suspended load that has been detected by the visual recognition unit.

Description

Work vehicles

[0001] The present invention relates to a work vehicle.

[0002] There has been active development of technologies for providing operational support to operators of work vehicles used on construction sites and for automating the operation. Patent Document 1 discloses technology related to a construction machinery control system that provides operational support to operators. This construction machinery control system has a camera that captures images of a load being carried by a work vehicle (specifically, a crane truck). The construction machinery control system then recognizes the size of the load based on the image of the load captured by the camera and data accumulated in a learning device.

[0003] Japanese Patent Application Laid-Open No. 2020-37475

[0004] In the above-mentioned work vehicle, it is desirable to be able to estimate the weight of the suspended load with high accuracy.

[0005] An object of the present invention is to provide a work vehicle that can accurately estimate the weight of a suspended load.

[0006] One aspect of the work vehicle of the present invention comprises a viewing unit having a photographing function and a distance detection function, and a control unit that controls the crane device, and the control unit calculates an estimated weight of the suspended load based on the image of the suspended load photographed by the viewing unit and information regarding the distance to the suspended load detected by the viewing unit.

[0007] According to the present invention, a work vehicle can be provided that can accurately estimate the weight of a suspended load.

[0008] Fig. 1 is a control flow diagram of a work vehicle according to an embodiment of the present invention. Fig. 2 is a side view of a work vehicle according to an embodiment of the present invention. Fig. 3 is a hydraulic circuit diagram of the work vehicle of Fig. 2. Fig. 4 is a control circuit diagram of the work vehicle of Fig. 2. Fig. 5 is an example of an image of the ground photographed by a visual confirmation device of the work vehicle of Fig. 2.

[0009] Next, embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to the following. Furthermore, the size or positional relationship of components shown in each drawing may be exaggerated for clarity of explanation.

[0010] <Embodiment> (Mobile Crane) Figure 2 is a side view of a mobile crane 10, which is one of the work vehicles according to this embodiment. The mobile crane 10 has a traveling vehicle body 11 equipped with a prime mover and multiple wheels 12 for travel. The mobile crane 10 also has outriggers 13 for ensuring stability during crane operation. A swivel base 14 is mounted on the upper surface of the traveling vehicle body 11. The swivel base 14 can rotate 360° in a horizontal plane using a swivel motor. The swivel base 14 is also provided with a cab 17 for the operator of the mobile crane 10. In the following description of the mobile crane 10, unless otherwise specified, the term "forward / backward direction" refers to the forward / backward direction when the mobile crane 10 is in a travelable state. Unless otherwise specified, the term "left / right direction" refers to the left / right direction when the mobile crane 10 is viewed from behind the mobile crane 10. Furthermore, the term "up / down direction" refers to the up / down direction when the mobile crane 10 is in a travelable state.

[0011] A slip ring and a swivel joint are provided between the traveling body 11 and the swivel base 14. The slip ring connects the electrical system between the traveling body 11 and the swivel base 4. The swivel joint connects the air system and hydraulic system between the traveling body 11 and the swivel base 4. In this specification, the mobile crane 10 is divided into the traveling body 11 and the crane apparatus mounted on the traveling body 11, separated by the slip ring and swivel joint. In other words, the crane apparatus includes the swivel base 14, the boom 15, etc.

[0012] A boom 15 is attached to the swivel base 14 so that it can be raised and lowered. The boom 15 is made up of multiple components. These components include a main boom 15a at the base end and multiple secondary boom stages that are telescopically inserted into the main boom 15a. In this embodiment, the secondary boom includes a first secondary boom 15b located at the base end and a second secondary boom 15c located at the tip end. In the illustrated example, there are two secondary booms, but the number may be one or less, or three or more. The extension and retraction of each secondary boom 15b, 15c is performed by a cylinder provided within the boom 15. In this embodiment, the boom component located at the tip end is the second secondary boom 15c.

[0013] The base end of the boom 15 is pivotally supported by the swivel base 14. A boom hoist actuator 46c is attached between the boom 15 and the swivel base 14. When the boom hoist actuator 46c extends, the boom 15 is raised. When the boom hoist actuator 46c retracts, the boom 15 is lowered.

[0014] A wire rope equipped with a hook 16 hangs from a boom head provided at the tip of the boom 15. The wire rope is guided along the boom 15 to the base of the boom 15 and wound onto a winch. A winch hydraulic motor 46b (see Figure 3) is provided on the winch. When the winch hydraulic motor 46b is driven to rotate the winch, the wire rope is wound or unwound. As a result, the hook 16 rises or falls. In this way, by combining the extension and retraction and elevation of the boom 15 and the raising and lowering of the hook 16, the mobile crane 1 lifts and lowers loads within a three-dimensional space.

[0015] In this embodiment, a visualization device 19 is provided on the tip side of the second sub-boom 15c. The visualization device 19 is an example of a visualization section, and has an imaging function for capturing an image of a suspended load placed on the ground or the like, and a distance detection function for detecting the distance to the suspended load.

[0016] Since the visualization device 19 is provided on the boom component located at the tip end, the load can be visualized by rotating the boom above the position where the load is placed. In other words, the visualization device 19 can recognize the load placed below the visualization device 19. In this way, it becomes easier to have the control device 33 recognize the load.

[0017] In this embodiment, the visualization device 19 is configured to include two devices. The first of the two devices is an imaging device that has the function of capturing an image of the suspended load. The second device is a distance measurement device that detects the distance to the suspended load. The distance measurement device is, for example, a LIDAR (Laser Imaging Detection and Ranging) device.

[0018] In the case of this embodiment, the visual confirmation device 19 can be configured by combining a distance measuring device with an imaging device that has been conventionally adopted in many models, thereby reducing the cost of the visual confirmation device 19. Furthermore, since the imaging device and the distance measuring device can be selected separately, the range of equipment choices can be expanded.

[0019] The visual confirmation device 19 is not limited to the above configuration. For example, the visual confirmation device 19 may be a stereo camera having a function of capturing an image of the suspended load and a function of measuring the distance to the suspended load.

[0020] If the visual confirmation device 19 is a stereo camera that has two functions, it becomes easy to secure space for the visual confirmation device 19 .

[0021] (Hydraulic Circuit 40) Figure 3 shows a hydraulic circuit diagram of the mobile crane 10 according to this embodiment. As shown in Figure 3, the hydraulic circuit 40 of the crane apparatus includes a hydraulic valve unit 41, a hydraulic pump 43, a main oil line 44, a return oil line 45, and a plurality of crane apparatus actuators 46a to 46d.

[0022] The hydraulic pump 43 supplies hydraulic oil in the tank 42 to the hydraulic valve unit 41. A main oil line 44 connects the hydraulic pump 43 and the hydraulic valve unit 41. A return oil line 45 connects the hydraulic valve unit 41 and the tank 42. The multiple crane apparatus actuators 46a to 46d perform operations such as extending and retracting the boom 15, hoisting the winch, lowering the winch, raising and lowering the boom 15, and swinging the boom 15. The crane apparatus actuators 46a to 46d are connected to the hydraulic valve unit 41.

[0023] The hydraulic pump 43 is connected to the engine 36 of the traveling vehicle body 11 via a PTO (power take-off) device. The hydraulic pump 43 is driven by the engine 36.

[0024] The hydraulic valve unit 41 has a boom extension / retraction control valve 47a, a winch control valve 47b, a boom hoist control valve 47c, and a boom rotation control valve 47d. The boom extension / retraction control valve 47a is connected to the boom extension / retraction actuator 46a. The winch control valve 47b is connected to the winch hydraulic motor 46b. The boom hoist control valve 47c is connected to the boom hoist actuator 46c. The boom rotation control valve 47d is connected to the boom rotation actuator 46d.

[0025] These switching control valves are each fitted with a lever, and an operator manually operates the lever to switch the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 43.

[0026] The control device 33 is also connected to an ECU (engine control unit) of the engine 36. The control device 33 controls at least the rotation speed of the engine 36. The control device 33 controls the rotation speed of the engine 36, thereby controlling the rotation speed of the hydraulic pump 43. In this way, the control device 33 adjusts the discharge amount of the hydraulic pump 43.

[0027] (Control Circuit) Figure 4 is a diagram showing a control circuit diagram of the mobile crane 10 according to this embodiment. The input side of the control device 33 is electrically connected to a boom length detector 39a, a boom rotation angle detector 39b, a boom hoist angle detector 39c, and a hoisting support force detector 39d. The output side of the control device 33 is electrically connected to an alarm 34, a boom extension / retraction control valve 47a, a winch control valve 47b, a boom hoist control valve 47c, and a boom rotation control valve 47d. The control device 33 is also electrically connected to an input / output device 20 equipped with a work screen 21.

[0028] The boom length detector 39a detects the length of the boom 15. The boom length detector 39a is, for example, a cord payout length detector. The cord payout length detector detects the amount of rotational displacement of the cord winder to detect the payout length of the length measurement cord.

[0029] The boom rotation angle detector 39b detects the rotation angle of the boom 15. The boom rotation angle detector 39b is disposed on the base side of the rotating base 14. For example, the boom rotation angle detector 39b is a potentiometer. A rotary encoder may be used as the boom rotation angle detector 39b instead of a potentiometer.

[0030] The boom hoist angle detector 39c detects the hoist angle of the boom 15. The boom hoist angle detector 39c is located on the base side of the boom 15. For example, the boom hoist angle detector 39c is a potentiometer. A rotary encoder may be used as the boom hoist angle detector 39c instead of a potentiometer.

[0031] The boom hoisting support force detector 39d detects the load suspended from the hook 16. In this embodiment, the boom hoisting support force detector 39d is a differential pressure gauge provided on the boom hoisting cylinder. The boom hoisting support force detector 39d sends the detected differential pressure to the control device 33.

[0032] When a predetermined situation occurs, the alarm 34 notifies the operator of the mobile crane 10 of that situation (in other words, the operating situation). An example of a predetermined situation is when the lifted load exceeds the rated load. As a result, the operator can recognize that the mobile crane 10 has reached the predetermined situation. In this embodiment, the alarm 34 is provided outside the operator's cab 17.

[0033] (Control Flow) FIG. 1 shows a control flow diagram for the work vehicle according to this embodiment. This control flow diagram is a control flow diagram when the operator of the mobile crane 10 enters the cab 17 and performs a load lifting operation. Before performing this operation, the control device 33 uses its learning function to learn about multiple load components. For example, the control device 33 repeatedly learns by importing CAD data of the load or physical data such as the material (density) of the components, and then renders and creates three-dimensional data of the load. From this three-dimensional data, the control device 33 then creates multiple two-dimensional images that can serve as plan views of the load. The control device 33 uses its learning function to store two-dimensional images of the load components, their names, material (density), and other information in a load database (not shown). The load database stores the two-dimensional images, material (density), and material (density) of the load components in association with the three-dimensional data of the load.

[0034] In step S1 of the control flow, the control device 33 photographs the suspended load using the viewing device 19 and detects information regarding the distance from the viewing device 19 to the suspended load (hereinafter simply referred to as "information regarding the distance of the suspended load"). The control device 33 corresponds to an example of a control unit. At this time, the suspended load is placed, for example, on the ground below the viewing device 19. The viewing device 19 has the function of photographing the suspended load and the function of detecting information regarding the distance of the suspended load, and therefore, in response to instructions from the control device 33, photographs the suspended load and detects information regarding the distance of the suspended load. The viewing device 19 sends the detected image of the suspended load and information regarding the distance of the suspended load to the control device 33. The control device 33 acquires information regarding the shape of the suspended load based on the image of the suspended load acquired from the viewing device 19. Furthermore, the control device 33 acquires information regarding the size of the suspended load by detecting the distances to multiple points on the surface of the suspended load based on the information regarding the distance of the suspended load acquired from the viewing device 19. The information regarding the size of the suspended load may be, for example, information indicating the scale (dimensions) of the suspended load.

[0035] 1, the control device 33 refers to the suspended load database and compares the two-dimensional image stored in the suspended load database with the image of the suspended load included in the image captured by the visualization device 19 (hereinafter simply referred to as the "suspended load image"). Then, the control device 33 acquires a two-dimensional image corresponding to the suspended load image from the suspended load database.

[0036] 1, the control device 33 acquires from the load database three-dimensional data of the suspended load (in other words, information about the shape of the suspended load) corresponding to the two-dimensional image acquired in step S2. Furthermore, the control device 33 uses a function for detecting the distance to the suspended load to confirm that the exact size of the suspended load matches this three-dimensional data.

[0037] Next, in step S4, the control device 33 identifies the material (density). Also, in step S4, the control device 33 may identify the component name of the suspended load. Specifically, the control device 33 acquires the material (density) associated with the three-dimensional data identified in step S3. The material (density) is an example of physical data. Also, the control device 33 may acquire the component name of the suspended load associated with the three-dimensional data identified in step S3.

[0038] In step S5, the control device 33 calculates an estimated weight of the suspended load based on the three-dimensional data identified in step S3 (in other words, information regarding the shape of the suspended load), the material (density) acquired in step S4, and information regarding the size of the suspended load acquired in step S1 (in other words, the scale of the suspended load).

[0039] In step S6, the control device 33 acquires attitude data of the crane apparatus from the boom length detector 39a, the boom rotation angle detector 39b, and the boom hoisting angle detector 39c.

[0040] In step S7, the control device 33 notifies the operator of the mobile crane 10 of the operating status of the crane device. For example, if the rating of the mobile crane 10 makes it impossible to lift the load, the control device 33 may issue a predetermined alarm sound from the alarm 34, display a message on the screen of the input / output device 20 such as a touch panel indicating that the rating has been exceeded, or display how close the traveling vehicle body 11 should be to the load.

[0041] In step S8, the control device 33 determines whether the crane can lift the load based on the estimated weight and the crane's attitude data, and notifies the operator of the result of the determination. FIG. 5 shows an example of a work screen 21 capturing a photograph of the ground taken by the viewing device 19 of the mobile crane 10 of this embodiment. The work screen 21 displays the tip of the second secondary boom 15c on the left side, along with a rectangular load 25. The load 25 is placed in a predetermined position. In other words, the load 25 is not being lifted by the mobile crane 10. For example, the control device 33 displays the estimated weight of the load 25 in the upper right corner of the work screen 21, acquires the crane's attitude data, and displays "Lifting Unavailable" as the crane's operating status. The work screen may also display a limit curve 22 indicating the crane's operating range. The operator of the mobile crane 10 estimates the distance between the limit curve 22 and the rectangular load 25. The operator then determines how close the traveling vehicle body 11 needs to be to the suspended load 25 in order to lift the suspended load 25. The control device 33 may also calculate the distance by which the traveling vehicle body 11 needs to approach the suspended load 25 in order to lift the suspended load 25, and display the calculated distance on the work screen 21. If the control device 33 determines in step S8 that lifting is possible, the control device 33 displays that lifting is possible. If the control device 33 determines in step S8 that lifting is impossible, the control device 33 notifies the operator to that effect. The control device 33 then returns the control process to step S1, and repeats this control flow.

[0042] By providing the visualization device 19 on the work vehicle, there is no need to provide a separate camera or other device outside of the work vehicle. This makes it easier for the control device 33 to recognize the suspended load. Furthermore, by linking physical parameters (specifically, the density of the suspended load) to the three-dimensional data corresponding to the suspended load, it is possible to calculate the estimated weight of the suspended load and to check the operating status of the crane apparatus before actually lifting the load. In other words, the control shown in FIG. 1 is performed before the crane apparatus lifts the suspended load.

[0043] Furthermore, in this embodiment, the crane determines whether or not it is possible to lift the load based on the estimated weight and the crane's attitude data. The operator is then notified of the determination result. This allows the operator to know whether or not the load can be lifted before starting the lifting operation. As a result, the operator can determine in advance whether the work location for the work vehicle is appropriate, thereby improving work efficiency.

[0044] (Other) In the above mobile crane 10, the configuration has been described in which the visualization device 19 is provided on the boom component located at the tip end of the boom 15, i.e., the second sub-boom 15c, but the present invention is not limited to this configuration. For example, the visualization device 19 could also be provided on the body of the mobile crane 10, such as on the swivel base 14. In this case, if the visualization device 19 is configured to include a photographing device and a distance measuring device, either one of them could be provided on the swivel base 14. In the claims, the phrase "equipped with a visualization device 19" means that the visualization device 19 is provided somewhere on the body of a work vehicle, such as the mobile crane 10.

[0045] It is also preferable that the distance measuring device constituting the visual recognition device 19 has a function of measuring the reflection intensity of the suspended load. In this case, the control device 33 can estimate the density of the suspended load based on the measured reflection intensity and use this estimated density as a physical parameter.

[0046] By using the density of the suspended load estimated based on the reflection intensity of the suspended load as a physical parameter, the time and effort required to manually input the physical parameters can be eliminated, and the operator of the work vehicle can check whether the data matches the manually input data.

[0047] (Note) A work vehicle according to a first example of the reference example of the present invention comprises a visualizing device having the function of photographing a suspended load and the function of detecting the distance to the suspended load, a crane device for lifting the suspended load, and a control device for controlling the crane device, wherein the control device acquires three-dimensional data corresponding to the suspended load recognized by the visualizing device, calculates an estimated weight of the suspended load by linking physical parameters to the three-dimensional data, and notifies the status of the operation of the crane device based on the estimated weight.

[0048] A work vehicle according to a second example of the reference example of the present invention, which cites the first example of the reference example described above, may be configured so that the control device notifies whether the crane device is capable of lifting the load based on the estimated weight and attitude data of the crane device.

[0049] A work vehicle according to a third example of the present invention, which cites the first example of the above-mentioned reference example, may be configured so that the visual confirmation device is provided on the boom component member located at the tip end of the boom components that make up the boom of the crane apparatus.

[0050] A work vehicle according to a fourth example of the reference example of the present invention, which cites the first example of the reference example described above, may be configured such that the visual confirmation device includes an imaging device having the function of photographing the suspended load, and a distance measuring device that detects the distance to the suspended load.

[0051] In a work vehicle according to a fifth example of the present invention, which cites the first example of the above-mentioned reference example, the visual confirmation device may be configured with a stereo camera having the function of photographing the suspended load and the function of measuring the distance to the suspended load.

[0052] A work vehicle according to a sixth example of the present invention, which cites the first example of the above-mentioned reference example, may be configured such that the distance measuring device has the function of measuring the reflection intensity of the suspended load, and the control device estimates the density of the suspended load based on the reflection intensity and uses this estimated density as a physical parameter.

[0053] The disclosures of the specification, drawings, and abstract contained in Japanese Patent Application No. 2023-97430, filed on June 14, 2023, are incorporated herein by reference in their entirety.

[0054] The work vehicle according to the present invention may be any of various crane vehicles.

[0055] 10 Mobile crane (work vehicle) 15 Boom 19 Visual confirmation device 33 Control device

Claims

1. A work vehicle comprising: a visualization unit having an image capturing function and a distance detection function; and a control unit that controls a crane apparatus, wherein the control unit calculates an estimated weight of the suspended load based on an image of the suspended load captured by the visualization unit and information regarding the distance to the suspended load detected by the visualization unit.

2. The work vehicle described in claim 1, wherein the control unit acquires information regarding the shape of the suspended load and information regarding the material of the suspended load based on an image of the suspended load, acquires information regarding the size of the suspended load based on information regarding the distance, and calculates the estimated weight based on the information regarding the shape, the material, and the size.

3. The work vehicle described in claim 2, wherein the control unit has a load database in which three-dimensional data of various suspended loads is stored in correspondence with two-dimensional images of the loads and the materials of the loads, and obtains from the load database information regarding the shape of the load and information regarding the material of the load corresponding to the acquired two-dimensional image of the load based on the image of the load, and calculates the estimated weight based on the information regarding the shape and information regarding the material acquired from the load database and the size information acquired based on the information regarding the distance.

4. The work vehicle according to claim 1, wherein the control unit notifies an operating status of the crane apparatus based on the estimated weight.

5. A work vehicle as described in claim 1, wherein the visualization unit is provided on a boom of the crane apparatus, and the image of the suspended load is an image of a suspended load placed below the visualization unit.

6. A work vehicle as described in claim 4, wherein the image of the load is an image of a load placed below the viewing unit, and the control unit determines whether the crane equipment is able to lift the load based on the estimated weight and posture data of the crane equipment, and notifies the determination result as the operating status.

7. A work vehicle as described in claim 1, wherein the visual confirmation section comprises: an imaging device having the imaging function; and a distance measuring device having the distance detection function.

8. A work vehicle as described in claim 2, wherein the visual recognition unit has a function of measuring the reflection intensity of the suspended load, and the control unit estimates density as information relating to the material based on the reflection intensity.

9. The work vehicle according to claim 1, wherein the visual recognition unit is a stereo camera.

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