Load-receiving base lifting device, specially-equipped vehicle, and object detection system of load-receiving base lifting device

Abstract

To appropriately detect an object on a load-receiving base and an object around the load-receiving base, even if a work situation is changed.SOLUTION: A load-receiving base lifting device includes a load-receiving base, a lifting mechanism for lifting the load-receiving base, an imaging device 65 for imaging the load-receiving base and the periphery of the load-receiving base, and an image processing device 70 for performing image processing on a photographic image obtained by photographing by the imaging device 65. The image processing device 70 includes a region setting part 71 for setting a specific region in the photographic image as a detection region, on the basis of the position or the attitude of the load-receiving base, and a detection part 72 for executing prescribed image processing on the detection region, and detecting an object projected on the detection region other than the load-receiving base.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a loading platform lifting device, a specially equipped vehicle, and an object detection system for a loading platform lifting device. [Background technology]

[0002] For example, as disclosed in Patent Document 1, a specially equipped vehicle equipped with a loading platform lifting device having a loading platform and a lifting mechanism for raising and lowering the loading platform has been known. By placing cargo on the loading platform and raising and lowering the loading platform using the lifting mechanism, the workload of loading and unloading work can be reduced. Furthermore, the loading platform lifting device disclosed in Patent Document 1 is equipped with an imaging device for capturing images of the area behind the vehicle in order to improve safety and work efficiency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6601930 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have studied ways to further improve safety and work efficiency by using an imaging device to capture images of the loading platform and its surroundings to detect objects on or around the loading platform, and as a result, have discovered the following problems.

[0005] The receiving platform moves up and down using a lifting mechanism, changing its height. In some cases, as in Patent Document 1, the receiving platform can change its position between an upright position and a horizontal position. The position and orientation of the receiving platform change depending on the work situation during the loading and unloading operation. When the position or orientation of the receiving platform changes, the positional relationship between the object to be detected and the receiving platform may also change. Furthermore, the position of the object to be detected may also change as the position or orientation of the receiving platform changes. Therefore, depending on the work situation, the position, size, shape, etc. of the object to be detected in the captured image may change, or the positional relationship between the object to be detected and the receiving platform in the captured image may change. Based on this, the inventor of the present application discovered that, depending on the work situation, it may be impossible to properly detect objects on or around the receiving platform.

[0006] The present invention has been made in consideration of the above points, and its purpose is to be able to properly detect objects on a loading platform or around the loading platform even when the work situation changes. [Means for solving the problem]

[0007] The loading platform lifting device according to the present invention is a loading platform lifting device provided at the rear of a cargo box of a specially equipped vehicle. The loading platform lifting device includes a loading platform, a lifting mechanism for raising and lowering the loading platform, an imaging device for capturing images of the loading platform and the area around the loading platform, and an image processing device for performing image processing on the captured image captured by the imaging device. The image processing device includes an area setting unit that sets a specific area in the captured image as a detection area based on the position or orientation of the loading platform, and a detection unit that performs predetermined image processing on the detection area in the captured image to detect objects other than the loading platform that appear in the detection area.

[0008] The position and posture of the receiving platform change depending on the work situation. When the position and posture of the receiving platform change, the positions of objects on or around the receiving platform may move, or the positional relationship between the objects and the receiving platform may change. The area setting unit of the image processing device provided in the receiving platform lifting device of the present invention sets a specific area in the captured image as a detection area based on the position or posture of the receiving platform. The detection unit detects objects captured in the detection area. This makes it possible to properly detect objects on or around the receiving platform even when the work situation changes.

[0009] According to a preferred embodiment, the area setting unit changes the detection area in accordance with the position or posture of the receiving platform relative to the imaging device.

[0010] When the position or posture of the receiving platform changes, the way the platform appears in the captured image also changes. With this configuration, the detection area can be changed in conjunction with the movement of the receiving platform, so the detection area can be changed according to changes in the way the platform appears in the captured image. This makes it possible to properly detect objects on or around the receiving platform even when the work situation changes.

[0011] According to a preferred embodiment, the area setting unit changes the position of the detection area in accordance with the position or attitude of the receiving platform relative to the imaging device.

[0012] When the position or posture of the receiving platform changes, the relative positional relationship between the imaging device and the receiving platform changes, which may cause the position of the receiving platform in the captured image to change. With this configuration, the position of the detection area can be changed in accordance with the change in the position of the receiving platform in the captured image, so objects on or around the receiving platform can be properly detected even if the work situation changes.

[0013] According to a preferred embodiment, the area setting unit changes the area of ​​the detection area in accordance with the position or attitude of the receiving platform relative to the imaging device.

[0014] When the position or posture of the receiving platform changes, the distance between the imaging device and the receiving platform changes, which may cause the size of the receiving platform in the captured image to change. With this configuration, the area of ​​the detection region can be changed in accordance with changes in the size of the receiving platform in the captured image, so objects on or around the receiving platform can be properly detected even if the work situation changes.

[0015] According to a preferred embodiment, the area setting unit changes the shape of the detection area in accordance with the position or orientation of the receiving platform relative to the imaging device.

[0016] When the position or posture of the receiving platform changes, the shape of the receiving platform in the captured image may change. With this configuration, the shape of the detection area can be changed in accordance with the change in the shape of the receiving platform in the captured image, so objects on or around the receiving platform can be detected appropriately even if the work situation changes.

[0017] According to a preferred embodiment, the platform lifting device includes a height sensor that measures the height of the platform, and the area setting unit changes the detection area based on the measurement value of the height sensor.

[0018] When the height of the receiving platform changes, the way the receiving platform is captured in the captured image may change. With this configuration, the detection area can be changed in conjunction with the lifting and lowering of the receiving platform, so objects on or around the receiving platform can be properly detected even when the receiving platform is being lifted or lowered.

[0019] According to a preferred embodiment, the platform is rotatable between an upright position and a horizontal position. The platform lifting device includes an inclination sensor that detects an inclination angle of the platform relative to a horizontal plane. The area setting unit changes the detection area based on the measurement value of the inclination sensor.

[0020] A platform lifting device capable of raising and lowering a platform to an upright position has been known. The above configuration allows the detection area to be changed according to the inclination angle of the platform relative to the horizontal plane. This allows for proper detection of objects on or around the platform, even while the platform is being rotated between a horizontal position and an upright position.

[0021] According to a preferred embodiment, the receiving platform is provided so as to be retractable below the cargo box. The receiving platform lifting device includes a storage sensor that detects whether the receiving platform is retracted below the cargo box. The area setting unit changes the detection area based on the detection result of the storage sensor.

[0022] A loading platform lifting device capable of storing a loading platform under a cargo box has been known. According to the above configuration, the detection area can be changed depending on whether the loading platform is stored under the cargo box. This allows for proper detection of objects on or around the loading platform even during the operation of moving the loading platform from its stored state under the cargo box.

[0023] According to a preferred embodiment, the loading platform lifting device includes a control device that controls the lifting mechanism. The area setting unit further sets a specific area within the detection area as a danger area where an object may come into contact with the loading platform. The image processing device includes an area discrimination unit that determines whether an object detected by the detection unit is located within the danger area, and an object discrimination unit that determines whether the object detected by the detection unit is a person or an obstacle based on predetermined conditions. When the area discrimination unit determines that the object detected by the detection unit is present in the danger area and the object discrimination unit determines that the object detected by the detection unit is a person or an obstacle, the control device prohibits operation of the loading platform.

[0024] With this configuration, when a person or an obstacle is in a location where there is a risk of contact with the loading platform, the loading platform does not rise or fall, so that the person or obstacle does not come into contact with the loading platform while it is in operation. Also, when a person or an obstacle enters a location where there is a risk of contact with the loading platform while the loading platform is being raised or lowered, the lifting or lowering of the loading platform stops, so that the person or obstacle does not come into contact with the loading platform while it is in operation.

[0025] According to a preferred aspect, the area setting unit further sets a specific area within the detection area as a danger area where an object may come into contact with the loading platform. The image processing device includes an area determination unit that determines whether an object detected by the detection unit is located within the danger area, and an object determination unit that determines whether the object detected by the detection unit is a person or an obstacle based on predetermined conditions. The loading platform lifting device includes an alarm device that issues an alarm when the area determination unit determines that the object detected by the detection unit is in the danger area and the object determination unit determines that the object detected by the detection unit is a person or an obstacle.

[0026] According to this configuration, when a person or an obstacle is in a location where there is a risk of contact with the loading platform, an alarm is issued by the alarm device. This allows the worker to become aware that a person or an obstacle is in an area where there is a risk of contact with the loading platform. Furthermore, if a person enters an area where there is a risk of contact with the loading platform, an alarm can be issued to the person, encouraging them to leave the area where there is a risk of contact with the loading platform 20.

[0027] According to a preferred embodiment, the loading platform lifting device includes a control device that controls the lifting mechanism so that at least one of the position and the attitude of the loading platform changes over time from the start of operation, and a timer that measures the time that the control device operates the lifting mechanism. The area setting unit changes the detection area in accordance with the value measured by the timer.

[0028] With this configuration, there is no need to install a separate sensor to detect the position and posture of the receiving platform, so objects on or around the receiving platform can be detected appropriately with a relatively simple configuration regardless of the work situation.

[0029] A specially equipped vehicle according to the present invention is equipped with any one of the above-described loading platform lifting devices.

[0030] The object detection system for a loading platform lifting device according to the present invention is an object detection system for a loading platform lifting device that includes a loading platform and a lifting mechanism for raising and lowering the loading platform. The object detection system for the loading platform lifting device includes an imaging device that captures images of the loading platform and its surroundings, and an image processing device that performs image processing on the captured image captured by the imaging device. The image processing device includes an area setting unit that sets a specific area in the captured image as a detection area based on the position or orientation of the loading platform, and a detection unit that performs predetermined image processing on the detection area in the captured image to detect objects other than the loading platform that appear in the detection area.

[0031] According to a preferred embodiment, the object detection system of the loading platform lifting device is configured to display the captured image on a display device and to display the detection area superimposed on the captured image.

[0032] This configuration allows the detection area to be visually confirmed. [Effects of the Invention]

[0033] According to the present invention, objects on the loading platform and objects around the loading platform can be detected appropriately even when the work situation changes. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a side view of a specially equipped vehicle according to a first embodiment. [Figure 2] FIG. 2 is a rear view of the specially equipped vehicle according to the first embodiment. [Figure 3]1 is a side view of the loading platform lifting device according to the first embodiment when the loading platform is in a horizontal position and at the upper end position. FIG. [Figure 4] 1 is a side view of the loading platform lifting device according to the first embodiment when the loading platform is in an upright position. [Figure 5] 1 is a side view of the loading platform lifting device according to the first embodiment when the loading platform is in a horizontal position and at its lowest end position. FIG. [Figure 6] 1 is a side view of the loading platform lifting device according to the first embodiment when the loading platform is in a ground contact position. FIG. [Figure 7] 1 is a block diagram of a receiving platform lifting and lowering device according to a first embodiment. [Figure 8] 1 is a block diagram of an object detection system according to a first embodiment. [Figure 9] 3 is an enlarged view of the base end side of the receiving platform according to the first embodiment when the receiving platform is in a horizontal position and at the upper end position. FIG. [Figure 10] 3 is an enlarged view of the base end side of the receiving platform according to the first embodiment when the receiving platform is in an upright position. FIG. [Figure 11] 2 is a diagram showing an example of a captured image captured by the imaging device according to the first embodiment. FIG. [Figure 12] FIG. 10 is a side view of the loading platform lifting and lowering device according to the second embodiment. [Figure 13] FIG. 10 is a block diagram of an object detection system according to a third embodiment. [Figure 14] FIG. 10 is a side view of the loading platform lifting device according to the fourth embodiment when the loading platform is at an intermediate height and at a rear end position. [Figure 15] FIG. 10 is a block diagram of a receiving platform lifting and lowering device according to a fourth embodiment. [Figure 16] FIG. 10 is a side view of the loading platform lifting and lowering device according to the fourth embodiment when the loading platform is folded. [Figure 17] FIG. 10 is a side view of the loading platform lifting device according to the fourth embodiment when the loading platform is in a stored state. [Figure 18] FIG. 10 is a block diagram of an object detection system according to a fourth embodiment. [Figure 19]FIG. 4 is a block diagram illustrating a modified example of the object detection system according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0035] First Embodiment A first embodiment of the present invention will now be described with reference to the drawings. Fig. 1 is a side view of a specially equipped vehicle 10 according to this embodiment. Fig. 2 is a rear view of the specially equipped vehicle 10 according to this embodiment. As shown in Fig. 1, the specially equipped vehicle 10 includes a cab 11, a chassis 12, a cargo box 15, and a cargo platform lifting device 16. A driver's seat (not shown) is provided inside the cab 11. The chassis 12 supports the cab 11 and the cargo box 15. The cargo box 15 is located behind the cab 11. The cargo box 15 is formed in a box shape. The cargo platform lifting device 16 is located behind the cargo box 15.

[0036] FIG. 3 is an enlarged view of the vicinity of the receiving platform lifting device 16. The receiving platform lifting device 16 is a device used when performing cargo handling operations such as loading and unloading cargo stored in a cargo box 15. The receiving platform lifting device 16 in this embodiment is a so-called upright storage type receiving platform lifting device. A support member 18 extending in the left-right direction is fixed to the rear end of the chassis 12. A connecting member 19 extending rearward is fixed to the support member 18. A bracket 17 is fixed to the connecting member 19. The receiving platform lifting device 16 is connected to the chassis 12 via the bracket 17, the support member 18, and the connecting member 19. The receiving platform lifting device 16 includes a receiving platform 20 and a lifting mechanism 30 that raises and lowers the receiving platform 20.

[0037] The receiving platform 20 is disposed behind the cargo box 15. The receiving platform 20 includes a receiving platform main body 21, a reinforcing member 22, and a connecting bracket 23. The receiving platform 20 is rotatable between a horizontal position and an upright position by a gate cylinder 36 (described later). Here, the horizontal position refers to a state in which the receiving platform main body 21 is parallel to a horizontal plane, as shown in FIG. 3. When the receiving platform 20 is in the horizontal position, the receiving platform main body 21 extends in the front-to-rear and left-to-right directions. Furthermore, the upright position refers to a state in which the receiving platform main body 21 and the cargo box 15 face each other, as shown in FIG. 4. When the receiving platform 20 is in the upright position, the receiving platform main body 21 extends in the up-down and left-to-right directions. In this specification, when the positional relationship between the receiving platform 20 and the receiving platform main body 21 is specified, unless otherwise specified, this refers to the positional relationship when the receiving platform 20 is in the horizontal position as shown in FIG. 3. For example, "disposed above the receiving platform 20" means being disposed above the receiving platform 20 in a horizontal position. The front side of the receiving platform 20 when it is in a horizontal position is the base end of the rotation of the receiving platform 20.

[0038] The receiving platform 20 is raised and lowered in a horizontal position by the lifting mechanism 30. In this embodiment, the upper end position of the lifting range of the receiving platform 20 is a position where the receiving platform main body 21 is flush with the floor surface of the interior of the cargo box 15, as shown in Fig. 3. The lower end position of the lifting range of the receiving platform 20 is a position where a link arm 34 of the lifting mechanism 30, which will be described later, contacts the floor surface, as shown in Fig. 5.

[0039] The receiving platform main body 21 is a member that serves as a platform on which cargo is placed during cargo handling operations. As shown in FIG. 2, the receiving platform main body 21 is formed in a rectangular shape. As shown in FIG. 3, the reinforcing body 22 is provided at the bottom of the receiving platform main body 21. As shown in FIG. 2, two reinforcing bodies 22 are provided side by side in the left-right direction. The reinforcing bodies 22 are hollow reinforcing members. As shown in FIG. 3, the connecting bracket 23 is provided on the base end side of the reinforcing body 22. The connecting bracket 23 is connected to a link arm 34 of the lifting mechanism 30, which will be described later, by a pin P5.

[0040] As shown in Fig. 3, the lifting mechanism 30 is configured by a link mechanism including a tilt link 31, a lift arm 32, a compression arm 33, a link arm 34, a lift cylinder 35, and a gate cylinder 36 (see Fig. 2). As shown in Fig. 2, two lifting mechanisms 30 are provided side by side in the left-right direction, but here, the left-side lifting mechanism 30 of the two lifting mechanisms 30 will be described. The left-side positional relationship of the components 31 to 36 of the right-side lifting mechanism 30 is reversed from that described below.

[0041] As shown in Figure 3, tilt link 31 extends in the vertical direction. An upper portion of tilt link 31 is rotatably connected to an upper portion of bracket 17 via pin P1. Tilt link 31 is provided so as to rotate between a state in which the lower portion of tilt link 31 contacts support member 18 and a state in which the lower portion of tilt link 31 is separated rearward from support member 18 (see Figure 6).

[0042] 3, the lift arm 32 extends in the front-rear direction. One end of the lift arm 32 is rotatably connected to the tilt link 31 via pin P2 below pin P1. The other end of the lift arm 32 is rotatably connected to the link arm 34 by pin P5.

[0043] The compression arm 33 is disposed below the lift arm 32. The compression arm 33 extends in the front-to-rear direction. One end of the compression arm 33 is rotatably connected via a pin P3. The other end of the compression arm 33 is rotatably connected to a link arm 34 via a pin P6.

[0044] The link arm 34 is disposed behind the cargo box 15. The link arm 34 is connected to the compression arm 33 by a pin P6. The link arm 34 is connected to a gate cylinder 36. The link arm 34 is connected to the connecting bracket 23 via a pin P5.

[0045] The lift cylinder 35 is disposed below the lift arm 32. The lift cylinder 35 is a cylinder that extends in the front-rear direction. In this embodiment, the lift cylinder 35 is a hydraulic cylinder. As shown in FIG. 3, one end of the lift cylinder 35 is rotatably connected to the tilt link 31 via pin P4. The other end of the lift cylinder 35 is rotatably connected to approximately the middle of the lift arm 32 via pin P7. When the lift cylinder 35 extends, the loading platform 20 rises. When the lift cylinder 35 contracts, the loading platform 20 descends. As shown in FIG. 5, when the lift cylinder 35 is further contracted when the loading platform 20 is in the lower end position, the loading platform 20 rotates clockwise around pin P5 as a fulcrum. As a result, as shown in FIG. 6, the loading platform 20 assumes a grounding position, and the tip 21b of the loading platform main body 21 contacts the floor surface.

[0046] As shown in FIG. 2, in this embodiment, the gate cylinder 36 is connected to the reinforcement body 22. The gate cylinder 36 is a cylinder that contracts and extends in the vertical direction. In this embodiment, the gate cylinder 36 is a hydraulic cylinder. As shown in FIG. 4, the gate cylinder 36 is connected to the link arm 34. The gate cylinder 36 is provided to change the position of the receiving platform 20 between a horizontal position and an upright position. When the receiving platform 20 is in the horizontal position (see FIG. 3), the gate cylinder 36 is contracted. When the gate cylinder 36 is extended, the receiving platform 20 rotates upward (counterclockwise in FIG. 3) around the front side of the receiving platform 20. This causes the receiving platform 20 to assume an upright position (see FIG. 4). When the receiving platform 20 is in the upright position, the gate cylinder 36 is extended. When the receiving platform 20 is in the upright position, if the gate cylinder 36 is contracted, the receiving platform 20 rotates downward (clockwise in FIG. 4) to assume a horizontal position.

[0047] 7 is a block diagram of the loading platform lifting device 16 according to this embodiment. As shown in FIG. 7, the loading platform lifting device 16 includes a hydraulic circuit 38, a control device 40, an operation device 42, a switch unit 46, a wireless device 50, a notification device 78, a display device 80, and an object detection system 100.

[0048] As shown in Figure 7, the gate cylinder 36 and the lift cylinder 35 are connected to a hydraulic circuit 38. Hydraulic oil is supplied from the hydraulic circuit 38 to the gate cylinder 36 and the lift cylinder 35, causing the gate cylinder 36 and the lift cylinder 35 to contract or extend. As shown in Figure 1, the hydraulic circuit 38 is disposed below the cargo box 15. The hydraulic circuit 38 is covered by a case. A hydraulic pump, a solenoid valve, etc. are provided inside the case. The configuration of the hydraulic circuit 38 is not particularly limited.

[0049] The control device 40 is a device that controls the operation of the loading platform lifting device 16. The control device 40 is, for example, a microcomputer. As shown in FIG. 7, the control device 40 is connected to the hydraulic circuit 38 so as to be able to communicate with it. The control device 40 controls the hydraulic circuit 38, thereby controlling the operation of the gate cylinder 36 and the lift cylinder 35.

[0050] The operation device 42 is a device used by an operator to operate the loading platform lifting device 16. The operation device 42 includes an operation unit 43 and a receiver 44. The operation unit 43 is electrically connected to the control device 40. Although detailed illustration is omitted, the operation unit 43 includes, for example, a button. While the operator presses the button on the operation unit 43, the control device 40 operates the gate cylinder 36 or the lift cylinder 35. As shown in FIG. 1, the operation unit 43 is disposed on the side of the chassis 12. Here, the operation unit 43 is disposed on the left side of the chassis 12, but it may also be disposed on the right side. The receiver 44 is capable of wireless communication. As shown in FIG. 7, the receiver 44 is wirelessly connected to the switch unit 46.

[0051] The switch unit 46 is a unit that switches ON and OFF operations by the operating device 42 and the wireless device 50. When the switch unit 46 is turned ON, the worker can operate the receiving platform lifting device 16 by the operating device 42 and the wireless device 50. On the other hand, when the switch unit 46 is turned OFF, the worker cannot operate the receiving platform lifting device 16 by the operating device 42 and the wireless device 50.

[0052] The main switch 47 is a switch that can be operated to switch between ON and OFF the operations by the operating device 42 and the wireless device 50. Although not shown in the drawings, the main switch 47 is provided with, for example, a switch button. Each time the worker presses the switch button, the operator can switch between ON and OFF the operations by the operating device 42 and the wireless device 50. The transmitter 48 is capable of wireless communication. As shown in FIG. 7 , the transmitter 48 is wirelessly connected to the receiver 44 of the operating device 42 and a receiving unit 54 of the wireless device 50, which will be described later. The transmitter 48 transmits the switching state of the main switch 47 to the receiver 44 and the receiving unit 54.

[0053] The wireless device 50 includes a power button 51, an up button 52, a down button 53, and a receiver 54. The receiver 54 is provided inside the wireless device 50. The power button 51 is a button for switching the power of the wireless device 50 on and off. The up button 52 and the down button 53 are buttons for raising and lowering the loading platform 20. While the worker presses the up button 52 or the down button 53, the control device 40 operates the gate cylinder 36 or the lift cylinder 35. The receiver 54 is wirelessly connected to the transmitter 48 of the switch unit 46. When the receiver 54 is not receiving a signal from the transmitter 48, the wireless device 50 is configured not to transmit a signal to the control device 40 even when the up button 52 or the down button 53 is pressed. In this embodiment, the wireless device 50 is a portable device that can be held and operated by the worker.

[0054] 8 is a block diagram of the object detection system 100. The object detection system 100 is a system that detects objects on the loading platform 20 and objects around the loading platform 20. The object detection system 100 includes a height sensor 55, a deployment sensor 57, a tilt sensor 61, an imaging device 65, and an image processing device 70. Note that the object detection system 100 may include sensors other than the height sensor 55, the deployment sensor 57, and the tilt sensor 61.

[0055] The height sensor 55 is a sensor that measures the height of the loading platform 20. As shown in FIG. 3, the height sensor 55 is attached to the lift arm 32. In this embodiment, the height sensor 55 is a sensor that measures the inclination angle of the lift arm 32. Here, the inclination angle of the lift arm 32 refers to the angle of the lift arm 32 with respect to the horizontal plane. As shown in FIGS. 3 and 5, when the height of the loading platform 20 changes, the inclination angle of the lift arm 32 also changes. The height sensor 55 measures the height of the loading platform 20 based on the inclination angle of the lift arm 32.

[0056] The deployment sensor 57 is a sensor that detects whether the receiving platform 20 is in an upright position. As shown in FIG. 9 , in this embodiment, the deployment sensor 57 is composed of a proximity switch 58 and a detection piece 59. The proximity switch 58 is attached to pin P6. The detection piece 59 is attached to link arm 34. When the proximity switch 58 detects the detection piece 59, it enters a detection state and transmits a signal to the control device 40. When the receiving platform 20 rotates between an upright position and a horizontal position, the positional relationship between the proximity switch 58 and the detection piece 59 changes. As shown in FIG. 10 , the deployment sensor 57 is configured so that the proximity switch 58 and the detection piece 59 are closest to each other when the receiving platform 20 is in an upright position. Therefore, when the receiving platform 20 is in an upright position, the deployment sensor 57 enters a detection state and transmits a signal to the control device 40. On the other hand, as shown in FIG. 9 , the deployment sensor 57 is configured so that the proximity switch 58 and the detection piece 59 are separated from each other when the receiving platform 20 is in a horizontal position. Therefore, when the loading platform 20 is in a horizontal position, the deployment sensor 57 is in a non-detecting state and does not transmit a signal to the control device 40.

[0057] The inclination sensor 61 is a sensor that measures the inclination angle of the receiving platform 20. Here, the inclination angle of the receiving platform 20 is the angle of the receiving platform main body 21 when the horizontal plane is used as the reference. As shown in Figure 9, the inclination sensor 61 is attached to the side of the receiving platform main body 21. When the receiving platform 20 rotates between an upright position and a horizontal position, the measurement value of the inclination sensor 61 changes.

[0058] The imaging device 65 is a device that captures images of the top of the receiving platform 20 or the surroundings of the receiving platform 20. The imaging device 65 is, for example, a camera. In this embodiment, as shown in FIG. 1, the imaging device 65 is provided at the top end of the cargo box 15. Therefore, the imaging device 65 captures images of the receiving platform 20 and the surroundings of the receiving platform 20 from above. However, the location of the imaging device 65 is not limited to this.

[0059] The image processing device 70 is a device that performs image processing on the image captured by the imaging device 65. As shown in Fig. 8, the image processing device 70 includes an area setting unit 71, a detection unit 72, an area discrimination unit 73, and an object discrimination unit 74. The image processing device 70 is connected to the control device 40 so as to be able to communicate with the control device 40, and is configured to transmit a signal to the control device 40 based on the result of image processing.

[0060] The area setting unit 71 sets a specific area in the captured image as the detection area C based on the position or posture of the receiving tray 20. In this embodiment, the area setting unit 71 sets an area including at least a portion of the receiving tray 20 shown in the captured image as the detection area C. In this embodiment, the area in the captured image that corresponds to the receiving tray 20 in real space and an area within 1 m around it is set as the detection area C. Note that the area setting unit 71 may also set an area in the captured image that does not include the receiving tray 20 as the detection area C.

[0061] Furthermore, the area setting unit 71 sets a specific area within the detection area C in the captured image as a danger area D. Here, the danger area D is set as an area where a person, an obstacle, or the like may come into contact with the receiving tray 20. In this embodiment, the receiving tray 20 in real space and an area within 30 cm of that area are considered to be an area where a person, an obstacle, or the like may come into contact with the receiving tray 20, and an area in the captured image corresponding to that area in real space is set as the danger area D. FIG. 11 shows an example of the detection area C and danger area D set by the area setting unit 71. In FIG. 11, the boundary of the detection area C is indicated by a two-dot chain line, and the boundary of the danger area D is indicated by a one-dot chain line. FIG. 11 shows the detection area C and danger area D when the receiving tray 20 is in a horizontal position and at the upper end position. Note that the method of setting the detection area C and danger area D is not limited to this. For example, the area in the captured image corresponding to the receiving platform 20 in real space and an area within 2 m around it may be set as the detection area C, and the area in the captured image corresponding to the receiving platform 20 in real space and an area within 1.5 m around it may be set as the danger area D. Also, the danger area D may be an area that is exactly the same as the position, size, and shape of the receiving platform 20 in the captured image. Also, the area setting unit 71 may set an area that is exactly the same as the detection area C as the danger area D.

[0062] The detection unit 72 performs image processing on the detection area C in the captured image captured by the imaging device 65 to detect an object captured in the detection area C. Because the detection unit 72 performs image processing only on the detection area C in the captured image, the amount of image processing can be reduced compared to when image processing is performed on the entire captured image. This reduces the time required for image processing and improves the object detection speed of the object detection system 100. Note that the method of object detection by the detection unit 72 is not particularly limited. The detection unit 72 may be configured to detect objects using known image recognition technology. Note that objects detected by the detection unit 72 are objects other than the loading platform 20. Objects detected by the detection unit 72 include people, obstacles, luggage, automated guided vehicles (AGVs), autonomous guided robots (AMRs), etc. Here, "people" includes not only workers performing loading and unloading work, but also people other than workers. Furthermore, "obstacles" refers to objects that interfere with loading and unloading work using the loading and unloading platform lifting device 16.

[0063] The area discrimination unit 73 determines whether an object detected by the detection unit 72 is located within the danger area D. The object discrimination unit 74 determines whether the object detected by the detection unit 72 is a person or an obstacle. If the area discrimination unit 73 determines that an object is located within the danger area D and the object discrimination unit 74 determines that the object is a person or an obstacle, the image processing device 70 transmits a signal to the control device 40, and the control device 40 prohibits the lifting / lowering or change of the posture of the receiving platform 20. Here, if at least a portion of the object detected by the detection unit 72 is located within the danger area D, the area discrimination unit 73 determines that the object is located within the danger area D. Note that the method by which the object discrimination unit 74 determines whether the object detected by the detection unit 72 is a person or an obstacle is not particularly limited. The object discrimination unit 74 may discriminate objects using known image recognition technology. For example, the object discrimination unit 74 may be configured to determine that an object detected by the detection unit 72 is a person if features of a human head are detected from the object. In addition, the object discrimination unit 74 may be configured to discriminate an object as an obstacle when it is determined that the object detected by the detection unit 72 is different from an object (such as a receiving platform 20 or luggage) pre-stored in the image processing device 70.

[0064] The alarm device 78 is a device that issues an alert when the image processing device 70 determines that a person or an obstacle is present in the danger area D. As shown in FIG. 7 , the alarm device 78 is communicably connected to the object detection system 100 via the control device 40. In this embodiment, the alarm device 78 issues an alert by sounding an alarm. Note that the configuration of the alarm device 78 is not limited to this, and for example, the alarm may be issued by using a lamp to irradiate light to the rear or side of the receiving platform 20.

[0065] The display device 80 is a device that displays the captured image captured by the imaging device 65. The display device 80 displays the captured image and also displays the detection area C and the danger area D superimposed on the captured image. The method of displaying the detection area C and the danger area D is not particularly limited. For example, the detection area C and the danger area D may be displayed by adding to the captured image the boundary lines between the detection area C, the danger area D, and other areas (lines corresponding to the two-dot chain line and the one-dot chain line in FIG. 11 ). Although not shown, in this embodiment, the display device 80 is provided inside the cab 11. The display device 80 may also show the area in the captured image occupied by the object detected by the detection unit 72. For example, the outline of the object appearing in the captured image may be added to the captured image to display it.

[0066] However, when the work situation of the cargo handling operation changes and the receiving platform 20 rises or falls or changes its position, the appearance of the receiving platform 20 in the captured image changes. Here, "the appearance of the receiving platform 20 changes in the captured image" refers to changes in the position, size, shape, etc. of the receiving platform 20 in the captured image. Even if the appearance of the receiving platform 20 in the captured image changes, if the detection area C remains fixed, it may not be possible to properly detect an object. Therefore, to properly detect an object regardless of the work situation, it is preferable to change the detection area C in accordance with the movement of the receiving platform 20. Therefore, the area setting unit 71 of the image processing device 70 according to this embodiment is configured to appropriately change the detection area C in accordance with the detection results of the height sensor 55, the deployment sensor 57, and the tilt sensor 61. Here, "changing the detection area C" means changing at least one of the position, area, and shape of the detection area C. Below, we will explain how the area setting unit 71 of this embodiment changes the detection area C.

[0067] The area setting unit 71 pre-sets a detection area C and a danger area D when the receiving platform 20 is in a specific position and posture, and stores the detection area C and danger area D in association with the detection results of the height sensor 55, the deployment sensor 57, and the tilt sensor 61. In this embodiment, the area setting unit 71 pre-stores the cases when the receiving platform 20 is in a horizontal posture and at the uppermost position (see FIG. 3), when the receiving platform 20 is in a horizontal posture and at the lowermost position (see FIG. 5), and when the receiving platform 20 is in an upright posture (see FIG. 4). The area setting unit 71 changes the pre-stored detection area C based on changes from the pre-stored detection results of the height sensor 55, the deployment sensor 57, and the tilt sensor 61. Note that the area setting unit 71 may change the danger area D instead of the detection area C. Alternatively, the area setting unit 71 may change the detection area C and the danger area D simultaneously.

[0068] For example, when the receiving platform 20 moves up and down in a horizontal position, the distance between the imaging device 65 and the receiving platform 20 changes, and therefore the size of the receiving platform 20 in the captured image changes. Because the imaging device 65 is provided at the upper end of the cargo box 15, the receiving platform 20 appears large in the captured image when it is at the top of the lifting range, and the receiving platform 20 appears small in the captured image when it is at the bottom of the lifting range. Therefore, the area setting unit 71 changes the area of ​​the detection area C stored in advance in accordance with changes in the measurement value of the height sensor 55. Specifically, the area setting unit 71 increases the area of ​​the detection area C as the measurement value of the height sensor 55 increases, and decreases the area of ​​the detection area C as the measurement value of the height sensor 55 decreases. Here, the area setting unit 71 may change the area of ​​the detection area C in proportion to the measurement value of the height sensor 55, may change the area of ​​the detection area C based on a mathematical formula using the measurement value of the height sensor 55, or may change the area of ​​the detection area C in stages according to the measurement value of the height sensor 55.

[0069] Furthermore, when the receiving platform 20 rotates between the upright position and the horizontal position, the inclination angle of the receiving platform 20 with respect to the horizontal plane changes, and the way the receiving platform 20 appears in the captured image changes. The area setting unit 71 changes the detection area C stored in advance in accordance with changes in the measurement value of the inclination sensor 61.

[0070] Next, the operation of the receiving platform lifting / lowering device 16 will be described. To operate the receiving platform lifting / lowering device 16, the worker may operate the operation unit 43 or the wireless device 50. Here, the operation when raising the receiving platform 20 will be described. That is, the worker operates the operation unit 43 to raise the receiving platform 20, or presses the lift button 52 on the wireless device 50.

[0071] In the state shown in Figure 6, the loading platform 20 has descended to the lowest end of its lifting range, and the tip 21b of the loading platform main body 21 is in contact with the ground. At this time, the lift cylinder 35 and gate cylinder 36 are in their most contracted states. At this time, the tilt link 31 rotates in a direction away from the support member 18, i.e., so that the lower end of the tilt link 31 faces rearward. In this state, hydraulic oil is supplied to the lift cylinder 35 from the hydraulic circuit 38 (see Figure 7), causing the lift cylinder 35 to extend. When the lift cylinder 35 extends, the lower part of the tilt link 31 rotates in a direction contacting the support member 18, and the lift arm 32 moves forward. The loading platform 20 rotates upward around pin P6.

[0072] As shown in Figure 5, when the lift arm 32 moves forward until the tilt link 31 contacts the support member 18, the platform main body 21 faces upward and assumes a horizontal position. In this state, when hydraulic oil is further supplied from the hydraulic circuit 38 to the lift cylinder 35 and the lift cylinder 35 extends, the lift arm 32 rotates upward around pin P2, and the compression arm 33 rotates upward around pin P3. This causes the platform 20 to rise.

[0073] As shown in FIG. 3, when the receiving platform 20 rises to the upper end of the lifting range, the receiving platform 20 and the cargo box 15 become flush. Specifically, the top surface of the receiving platform main body 21 and the floor of the cargo box 15 become flush. Note that "flush" here means that the heights of the top surface of the receiving platform main body 21 and the floor of the cargo box 15 are substantially the same. "Substantially the same height" between the top surface of the receiving platform main body 21 and the floor of the cargo box 15 includes both a case where they are completely flush and a case where there is a slight difference in height between them. Note that it is preferable that there is substantially no gap between the top surface of the receiving platform main body 21 and the floor of the cargo box 15 when they are flush. "Substantially no gap" between the top surface of the receiving platform main body 21 and the floor of the cargo box 15 includes a case where there is no gap between them and a case where there is a slight gap (see FIG. 3).

[0074] When the top surface of the receiving platform main body 21 is flush with the floor of the interior of the packing box 15 (as shown in FIG. 3 ), a worker may carry a package out of or into the packing box 15. For example, when carrying a package out of the packing box, the package is first loaded onto the receiving platform 20 from the interior of the packing box. Since the top surface of the receiving platform main body 21 is flush with the floor of the interior of the packing box 15, the worker can easily load the package from the interior of the packing box onto the receiving platform 20. For example, in the case of a package with casters, the worker can easily move the package from the packing box 15 to the receiving platform 20 by simply pushing or pulling the package from the packing box 15 toward the receiving platform 20. Thereafter, the lift cylinder 35 is extended to lower the receiving platform 20, as shown in FIGS. 5 and 7 .

[0075] Meanwhile, in the state shown in FIG. 3, by further operating the operating unit 43 to raise the load or by pressing the lift button 52 on the wireless device 50, hydraulic oil is supplied from the hydraulic circuit 38 to the gate cylinder 36. When hydraulic oil is supplied to the gate cylinder 36, the gate cylinder 36 extends. When the gate cylinder 36 extends, the loading platform 20 rotates counterclockwise around the pin P6. As shown in FIG. 4, when the gate cylinder 36 extends, the loading platform main body 21 and the cargo box 15 face each other, and the loading platform 20 assumes an upright position. At this time, the gate cylinder 36 is in its most extended state.

[0076] For example, if the object detection system 100 detects a person or an obstacle in the danger zone D in the captured image while the platform lifting device 16 is operating as described above, the control device 40 controls the hydraulic circuit 38 to stop the operation of the platform 20, and the alarm device 78 issues an alert. This prevents a person or an obstacle from coming into contact with the platform 20 while it is in operation. Furthermore, if a person or an obstacle is detected in the danger zone D before the platform lifting device 16 is operated, the control device 40 prohibits the operation of the platform 20, and the alarm device 78 issues an alert. This prevents the platform 20 from moving if a person or an obstacle is present in an area where the platform 20 may come into contact with the platform 20 before the loading / unloading operation begins. Furthermore, the platform 20 does not move even if a person is standing on the platform 20. Furthermore, the alert from the alarm device 78 allows the worker to become aware that a person or an obstacle is present in an area where the platform 20 may come into contact with the platform 20. In addition, if a person enters an area where there is a possibility of contact with the receiving platform 20, an alarm can be sent to the person in question, and they can be urged to leave the area where there is a possibility of contact with the receiving platform 20.

[0077] In the above description, when the object detection system 100 detects a person or an obstacle in the danger area D, the operation of the receiving platform 20 is prohibited. However, in the present embodiment, it is also possible to permit operation when an object such as luggage is detected in the danger area D. For example, when the object detection system 100 detects that luggage is properly loaded on the receiving platform 20, the control device 40 may be configured to permit the lifting and lowering of the receiving platform 20. Here, the object detection system 100 may be configured to determine that luggage is properly loaded on the receiving platform 20 when, for example, luggage is placed evenly on the receiving platform 20. The object detection system 100 may set a separate area separate from the danger area D and determine whether luggage is in an appropriate position. This allows the receiving platform 20 to be lifted and lowered with luggage properly loaded on the receiving platform 20, making it easier to ensure safety during loading and unloading operations and reducing the burden on workers.

[0078] Furthermore, when the object detection system 100 detects that an automated guided vehicle (AGV) or an autonomous guided robot (AMR) is placed on the receiving platform 20, the control device 40 may be configured to permit the receiving platform 20 to be raised or lowered. Therefore, when an AGV or AMR carrying a load is placed on the receiving platform 20, the receiving platform 20 can be raised or lowered. This further reduces the burden of loading and unloading work on workers.

[0079] The receiving platform lifting device 16 according to this embodiment includes an imaging device 65 that captures images of the receiving platform 20 and its surroundings, and an image processing device 70 that performs image processing on the captured image captured by the imaging device 65. The image processing device 70 includes an area setting unit 71 and a detection unit 72. The area setting unit 71 sets a specific area in the captured image as a detection area C based on the position or posture of the receiving platform 20. The detection unit 72 performs predetermined image processing on the detection area C in the captured image, and detects objects other than the receiving platform 20 that appear in the detection area C.

[0080] The position and posture of the receiving platform 20 change depending on the work situation. When the position and posture of the receiving platform 20 change, the position, size, shape, etc. of an object in the captured image may change, and the positional relationship between the object and the receiving platform 20 in the captured image may also change. Therefore, if the detection area C is set uniformly regardless of the position and posture of the receiving platform 20, there is a possibility that objects on or around the receiving platform 20 may not be properly detected. However, according to the receiving platform lifting device 16 of this embodiment, the area setting unit 71 sets the detection area C based on the position or posture of the receiving platform 20. Therefore, regardless of the work situation, objects on or around the receiving platform 20 can be properly detected.

[0081] When the position or attitude of the receiving platform 20 changes, the way the receiving platform 20 appears in the captured image changes. According to this embodiment, the area setting unit 71 changes the detection area C according to the position or attitude of the receiving platform 20 relative to the imaging device 65. More specifically, the area setting unit 71 changes at least one of the position, area, and shape of the detection area C according to the position or attitude of the receiving platform 20 relative to the imaging device 65. This makes it possible to change the detection area C in conjunction with the operation of the receiving platform 20. Even while the receiving platform 20 is operating, objects on or around the receiving platform 20 can be properly detected.

[0082] According to this embodiment, the receiving platform lifting device 16 is equipped with a height sensor 55 that measures the height of the receiving platform 20. The area setting unit 71 changes the detection area C based on the measurement value of the height sensor 55. This allows the detection area C to be changed in conjunction with the lifting and lowering of the receiving platform 20. Even when the receiving platform 20 is in the middle of being lifted or lowered, objects on or around the receiving platform 20 can be properly detected.

[0083] According to this embodiment, the receiving platform 20 is rotatable between an upright position and a horizontal position. The receiving platform lifting device 16 is equipped with an inclination sensor 61 that detects the inclination angle of the receiving platform 20 with respect to the horizontal plane. The area setting unit 71 changes the detection area C based on the measurement value of the inclination sensor 61. This makes it possible to properly detect objects on or around the receiving platform 20 even during the operation of rotating the receiving platform 20 between the horizontal position and the upright position.

[0084] According to this embodiment, the receiving platform lifting device 16 includes a control device 40 that controls the lifting mechanism 30. An area setting unit 71 of the image processing device 70 further sets a specific area within the detection area C as a danger area D where an object may come into contact with the receiving platform 20. The image processing device 70 also includes an area discrimination unit 73 and an object discrimination unit 74. The area discrimination unit 73 determines whether an object detected by the detection unit 72 is located within the danger area D. The object discrimination unit 74 determines whether the object detected by the detection unit 72 is a person or an obstacle based on predetermined conditions. If the area discrimination unit 73 and the object discrimination unit 74 determine that a person or an obstacle is located within the danger area D, the control device 40 prohibits the operation of the receiving platform 20. As a result, when a person or an obstacle is present in a location where there is a risk of contact with the receiving platform 20, the receiving platform 20 does not rise or fall, preventing the person or obstacle from coming into contact with the receiving platform 20 during operation. Furthermore, when a person or an obstacle enters a location where there is a risk of contact with the loading platform 20 while the loading platform 20 is being raised or lowered, the lifting or lowering of the loading platform 20 is stopped, so that the person or obstacle will not come into contact with the loading platform 20 while it is in operation.

[0085] According to this embodiment, an alarm device 78 is provided that issues an alarm when the area discrimination unit 73 and the object discrimination unit 74 determine that a person or an obstacle is inside the danger area D. This allows the worker to notice that a person or an obstacle is present in an area where there is a possibility of contact with the receiving platform 20. Furthermore, if a person has entered an area where there is a possibility of contact with the receiving platform 20, an alarm can be issued to the person who has entered, and the person can be urged to leave the area where there is a possibility of contact with the receiving platform 20.

[0086] According to this embodiment, the loading platform lifting device 16 is equipped with a display device 80 that displays the captured image and also displays the detection area C and danger area D superimposed on the captured image. This allows the detection area C and danger area D to be visually confirmed. This makes it easy for workers, vehicle drivers, etc. to check whether there is a person or obstacle in an area that may come into contact with the loading platform 20.

[0087] Second Embodiment Next, a second embodiment of the present invention will be described. In the description of the second embodiment, components that perform the same functions as those in the first embodiment will be designated by the same reference numerals as those in the first embodiment, and duplicated descriptions will be omitted or simplified.

[0088] In this embodiment, as shown in Fig. 12, the imaging device 65 is attached to the rear of the chassis 12. The imaging device 65 captures images of the receiving platform 20 and its surroundings from the front. As in the first embodiment, the area setting unit 71 pre-stores the detection area C and the danger area D when the receiving platform 20 is in a horizontal position and at the uppermost position, when the receiving platform 20 is in a horizontal position and at the lowermost position, and when the receiving platform 20 is in an upright position, in association with the detection results of the height sensor 55, the deployment sensor 57, and the tilt sensor 61. However, because the arrangement of the imaging device 65 is different from that in the first embodiment, the position, area, shape, etc. of the detection area C and the danger area D in the pre-stored captured image are different from those in the first embodiment.

[0089] For example, when the receiving platform 20 moves up and down in a horizontal position, the position of the receiving platform 20 in the captured image changes. If the receiving platform 20 is at the bottom end position, the receiving platform 20 appears at a relatively low position in the captured image. If the receiving platform 20 is at the top end position, the receiving platform 20 appears at a relatively high position in the captured image. Therefore, the area setting unit 71 changes the position of the pre-stored detection area C in the vertical direction in the captured image in accordance with changes in the measurement value of the height sensor 55. In reality, the area and shape of the receiving platform 20 in the captured image also change as the receiving platform 20 moves up and down, so the area and shape of the detection area C may also be changed at the same time.

[0090] Third Embodiment Next, a third embodiment of the present invention will be described. In the description of the third embodiment, the same reference numerals as in the first embodiment will be used for components that perform the same functions as in the first embodiment, and duplicated descriptions will be omitted or simplified.

[0091] Fig. 13 is a block diagram of an object detection system 100 according to the third embodiment. As shown in Fig. 13, the object detection system 100 of this embodiment does not include the height sensor 55, the deployment sensor 57, or the tilt sensor 61, and instead includes a timer 63. The timer 63 measures the time that the control device 40 operates the lifting mechanism 30.

[0092] As in the first embodiment, the area setting unit 71 of the image processing device 70 according to this embodiment pre-stores the detection area C and danger area D for when the receiving platform 20 is in a horizontal position and at the upper end position, when the receiving platform 20 is in a horizontal position and at the lower end position, and when the receiving platform 20 is in an upright position. These detection area C and danger area D are stored in association with the position, area, shape, etc. of the receiving platform 20 in the captured image when the receiving platform 20 is in each position and posture. When the receiving platform 20 moves, the timer 63 starts measuring the operation time. The area setting unit 71 is configured to change at least one of the position, area, and shape of the pre-stored detection area C according to the measurement value of the timer 63 and the movement direction of the receiving platform 20. Here, information regarding the movement direction of the receiving platform 20 is obtained by the image processing device 70 receiving signals via the control device 40 from the operating device 42 or wireless device 50 when the worker operates the operating device 42 or wireless device 50.

[0093] For example, if the worker presses the lowering button 53 when the receiving platform 20 is in a horizontal position and at the upper end, the receiving platform 20 will descend. The timer 63 starts measuring time as soon as the receiving platform 20 starts to descend. If the imaging device 65 is attached to the upper end of the box 15, the receiving platform 20 will appear smaller in the captured image as it descends. Therefore, as the measurement value of the timer 63 increases, the receiving platform 20 will appear smaller in the captured image. In such a case, the area setting unit 71 of this embodiment reduces the area of ​​the detection area C as the measurement value of the timer 63 increases.

[0094] According to this embodiment, the receiving platform lifting device 16 includes a control device 40 that controls the lifting mechanism 30 so that at least one of the position and posture of the receiving platform 20 changes over time from the start of operation, and a timer 63 that measures the time that the control device 40 operates the lifting mechanism 30. The area setting unit 71 changes the detection area C according to the measurement value of the timer 63. With this configuration, there is no need to separately install a sensor that detects the position and posture of the receiving platform 20, and with a relatively simple configuration, objects on or around the receiving platform 20 can be appropriately detected regardless of the work situation.

[0095] <Fourth embodiment> Next, a fourth embodiment of the present invention will be described. In the description of the fourth embodiment, components that perform the same functions as those in the first embodiment will be designated by the same reference numerals as those in the first embodiment, and duplicated descriptions will be omitted or simplified.

[0096] FIG. 14 is an enlarged view of the vicinity of the receiving platform lifting device 16B according to the fourth embodiment. FIG. 15 is a block diagram of the receiving platform lifting device 16B according to the fourth embodiment. The receiving platform lifting device 16B according to the fourth embodiment is a so-called underfloor storage type receiving platform lifting device. As shown in FIG. 14, the receiving platform lifting device 16B according to the fourth embodiment includes a receiving platform 20B, a lifting mechanism 30B, and a slide mechanism 80B. As shown in FIG. 16, the receiving platform 20B is configured to be foldable. As shown in FIG. 17, the receiving platform lifting device 16B is configured so that the receiving platform 20B can be stored below the cargo box 15 by the slide mechanism 80B. In this embodiment, the receiving platform 20B is folded manually.

[0097] The lifting mechanism 30B can use a link mechanism similar to that of the first embodiment. However, in this embodiment, since the receiving platform 20B can be stored below the cargo box 15 as described above, the lifting mechanism 30B does not need to be equipped with a gate cylinder 36 that rotates the receiving platform 20B between a horizontal position and an upright position. In this embodiment, the lifting mechanism 30B does not include a gate cylinder 36. As in the first embodiment, the lifting mechanism 30B raises and lowers the receiving platform 20B between an upper end position and a lower end position.

[0098] The slide mechanism 80B is a mechanism that moves the receiving platform 20B in the front-rear direction between a rear end position and a front end position. As shown in FIG. 14, the slide mechanism 80B is provided at the bottom of the chassis 12. The slide mechanism 80B moves the receiving platform 20B in the front-rear direction at a height between the upper end position and the lower end position (hereinafter referred to as the intermediate height). As shown in FIG. 16, when the receiving platform 20B is in the rear end position, the receiving platform 20B is located behind the cargo box 15 and is not overlapping with the cargo box 15 when viewed from above. As shown in FIG. 17, when the receiving platform 20B is in the front end position, the receiving platform 20B is overlapping with the cargo box 15 when viewed from above. When the receiving platform 20B is in the front end position, the receiving platform 20B is stored below the cargo box 15.

[0099] The slide mechanism 80B includes a guide rail 81B, a slider 82B, and a slide cylinder 84B. The guide rail 81B is provided at the bottom of the chassis 12. The guide rail 81B extends in the front-to-rear direction. The slider 82B is provided to slide on the guide rail 81B. Therefore, the slider 82B is movable in the front-to-rear direction along the guide rail 81B. The lifting mechanism 30B is connected to the slider 82B. The slide cylinder 84B is a drive device that moves the slider 82B in the front-to-rear direction. In this embodiment, the slide cylinder 84B is a hydraulic cylinder. The slide cylinder 84B is connected to the hydraulic circuit 38 (see Figure 15). When the slide cylinder 84B is driven, the receiving platform 20B and the lifting mechanism 30B move in the front-to-rear direction together with the slider 82B.

[0100] FIG. 18 is a block diagram of an object detection system 100B according to this embodiment. The object detection system 100B includes an imaging device 65, an image processing device 70, a height sensor 55, a folding sensor 86B, a rear end sensor 88B, and a storage sensor 90B. The imaging device 65 and the image processing device 70 have the same configurations as those in the first embodiment, and detailed description thereof will be omitted here. In this embodiment, the imaging device 65 is also disposed at the upper end of the cargo box 15. The height sensor 55, the folding sensor 86B, the rear end sensor 88B, and the storage sensor 90B are sensors that detect the state of the cargo receiving platform lifting / lowering device 16B. The height sensor 55 is a sensor that measures the height of the cargo receiving platform 20B, and is attached to the lift arm 32 as in the first embodiment.

[0101] The folding sensor 86B is a sensor that detects whether the receiving tray 20B is folded. As shown in Figure 16, the folding sensor 86B is attached to the receiving tray 20B. The folding sensor 86B is, for example, a limit switch. When the receiving tray 20B is in a folded state, the folding sensor 86B enters a detection state and transmits a signal to the control device 40.

[0102] The rear end sensor 88B is a sensor that detects the position of the slider 82B. Therefore, the rear end sensor 88B can detect the position of the receiving platform 20B in the front-to-rear direction. As shown in FIG. 16, the rear end sensor 88B is attached to the rear of the guide rail 81B. The rear end sensor 88B is, for example, a proximity switch. When the slider 82B approaches the rear end sensor 88B, the rear end sensor 88B enters a detection state and transmits a signal to the control device 40. Therefore, the rear end sensor 88B transmits a signal to the control device 40 when the receiving platform 20B is at the rear end position.

[0103] The storage sensor 90B is a sensor that detects the position of the slider 82B. Therefore, the storage sensor 90B can detect the position of the receiving platform 20B in the front-to-rear direction. As shown in FIG. 17, the storage sensor 90B is attached to the front of the guide rail 81B. The storage sensor 90B is, for example, a proximity switch. When the slider 82B approaches the storage sensor 90B, the storage sensor 90B enters a detection state and transmits a signal to the control device 40. Therefore, the storage sensor 90B transmits a signal to the control device 40 when the receiving platform 20B is at the front end position. This allows the storage sensor 90B to detect whether the receiving platform 20B is retracted or not.

[0104] Next, a description will be given of how the area setting unit 71 of the image processing device 70 according to this embodiment sets the detection area C and how the detection area C is changed. As in the first embodiment, the area setting unit 71 pre-sets the detection area C and danger area D when the receiving tray 20B is in a specific position and posture, and stores the detection area C and danger area D in association with the detection results of the height sensor 55, folding sensor 86B, rear end sensor 88B, and storage sensor 90B. In this embodiment, the case where the receiving tray 20B is at an intermediate height and in the rear end position (see FIG. 14) is pre-stored.

[0105] For example, when the receiving platform 20B moves up and down, the size of the receiving platform 20B changes in the captured image. When the receiving platform 20B moves down, the receiving platform 20B appears smaller in the captured image. When the receiving platform 20B moves up, the receiving platform 20B appears larger in the captured image. When the receiving platform 20B moves up and down, the area setting unit 71 changes the area of ​​the detection area C that is stored in advance in accordance with changes in the measurement value of the height sensor 55. In more detail, the area setting unit 71 increases the area of ​​the detection area C as the receiving platform 20B moves upward, and decreases the area of ​​the detection area C as the receiving platform 20B moves downward.

[0106] As the receiving platform 20B moves from the front end position to the rear end position, it no longer overlaps with the cargo box 15 when viewed from above and appears in the captured image as it moves rearward from the front end position. Therefore, as the receiving platform 20B moves rearward, the area of ​​the receiving platform 20B that appears in the captured image increases. Furthermore, because the receiving platform 20B is moving rearward, the position of the receiving platform 20B in the captured image also moves. In this way, as the receiving platform 20B moves in the forward / rearward direction, the way the receiving platform 20B appears in the captured image changes. The area setting unit 71 changes the position and area of ​​the detection area C that is stored in advance based on the detection results of the rear end sensor 88B and the storage sensor 90B. When the receiving platform 20B moves rearward from the front end position to the rear end position, the storage sensor 90B changes from a detection state to a non-detection state. When the storage sensor 90B changes from a detecting state to a non-detecting state, the area setting unit 71 moves the detection area C rearward and increases the area of ​​the detection area C. On the other hand, when the receiving tray 20B moves forward from the rear end position to the front end position, the rear end sensor 88B changes from a detecting state to a non-detecting state. When the rear end sensor 88B changes from a detecting state to a non-detecting state, the area setting unit 71 moves the detection area C forward and decreases the area of ​​the detection area C.

[0107] According to this embodiment, the receiving platform 20B is provided so as to be storable below the cargo box 15. The receiving platform lifting device 16B is equipped with a storage sensor 90B that detects whether the receiving platform 20B is stored below the cargo box 15. The area setting unit 71 changes the detection area C based on the detection result of the storage sensor 90B. This allows objects around the receiving platform 20B to be properly detected when the receiving platform 20B is moved backward from a state where it is stored below the cargo box 15.

[0108] <Other embodiments> Although the embodiments of the present invention have been described above, the first to fourth embodiments are merely examples, and various other embodiments are possible.

[0109] In the first, second, and fourth embodiments described above, the height sensor 55 measures the height of the loading platform 20 by measuring the tilt angle of the lift arm 32. However, the height sensor 55 is not limited to this. For example, the height sensor 55 may be a rotation speed sensor attached to the hydraulic pump of the hydraulic circuit 38. Furthermore, the height sensor 55 may be a wire-type displacement sensor or the like.

[0110] The configuration of the receiving platform lifting device 16 is not limited to the above-described embodiment. For example, it may be a so-called vertical lifting type receiving platform lifting device that includes a pair of vertically extending support posts provided on the left and right sides of the rear of the cargo box 15 and a slider that moves up and down along the support posts together with the receiving platform.

[0111] In the above-described embodiment, the image processing device 70 is provided separately from the imaging device 65, but the image processing device 70 may be built into the imaging device 65. Furthermore, the imaging device 65 may be configured to be able to communicate with a server external to the specially equipped vehicle 10. In this case, the image processing device 70 may be provided in the external server.

[0112] The imaging device 65 may use a wide-angle lens. By using an imaging device 65 with a wide-angle lens, the imaging range can be widened. On the other hand, when imaging is performed using a wide-angle lens, the receiving tray 20 appears distorted in the captured image. When the receiving tray 20 moves and the position of the receiving tray 20 in the captured image changes, the degree of distortion of the receiving tray 20 in the captured image may also change. Therefore, the area setting unit 71 of the image processing device 70 may be configured to change the shape of the detection area C according to the distortion of the receiving tray 20 in the captured image.

[0113] In the fourth embodiment described above, two sensors, the rear end sensor 88B and the storage sensor 90B, were provided to detect the forward-backward position of the receiving tray 20B. However, the receiving tray 20B is more likely to come into contact with a person or an obstacle when it is at the rear end position than when it is at the front end position. Therefore, when the rear end sensor 88B changes from a detecting state to a non-detecting state, the area setting unit 71 does not necessarily need to move the detection area C forward and reduce the area of ​​the detection area C. Therefore, the sensor that detects the forward-backward position of the receiving tray 20B may be just the storage sensor 90B.

[0114] The number of sensors for detecting the front-rear position of the receiving platform 20B may be three or more. This allows the front-rear position of the receiving platform 20B to be detected at more positions, and allows the area setting unit 71 to change the detection area C more appropriately.

[0115] In the above-described fourth embodiment, the receiving tray 20B is folded manually. However, the receiving tray 20B may be folded automatically. When the receiving tray 20B is folded automatically, there is a risk that a person or an obstacle may come into contact with the receiving tray 20B during the folding operation. Therefore, the area setting unit 71 may be configured to change the detection area C based on the detection result of the folding sensor 86B. When the receiving tray 20B is folded, the area of ​​the receiving tray 20B that appears in the captured image becomes smaller. The area setting unit 71 may change the area of ​​the detection area C based on the detection result of the folding sensor 86B. When the folding sensor 86B changes from a non-detecting state to a detecting state, the area setting unit 71 may reduce the area of ​​the detection area C. On the other hand, when the folding sensor 86B changes from a detecting state to a non-detecting state, the area setting unit 71 may increase the area of ​​the detection area C.

[0116] In the above-described first to fourth embodiments, the area setting unit 71 changes the detection area C, but the area setting unit 71 may change the danger area D instead of the detection area C. Furthermore, the area setting unit 71 may change the detection area C and the danger area D at the same time.

[0117] In the first embodiment described above, the height sensor 55, the unfolding sensor 57, and the tilt sensor 61 are connected to the image processing device 70 so as to be able to communicate directly with the image processing device 70. However, as shown in Fig. 19, the height sensor 55, the unfolding sensor 57, and the tilt sensor 61 may be provided so as to be able to communicate indirectly with the image processing device 70 via the control device 40. Similarly, the folding sensor 86B, the rear end sensor 88B, and the retracting sensor 90B of the fourth embodiment may also be provided so as to be able to communicate indirectly with the image processing device 70 via the control device 40. [Explanation of symbols]

[0118] 10 Specially equipped vehicles 15 Packing box 16 Loading platform lifting device 20 Loading platform 30 Lifting mechanism 40 Control device 55 Height sensor 61 Inclination sensor 63 Timer 65 Imaging device 70 Image processing device 71 Area setting section 72 Detector 73 Area discrimination part 74 Object discrimination unit 78 Alarm device 80 Display device 90B Storage Sensor 100 Object Detection System

Claims

1. A loading platform lifting device provided at the rear of a loading box of a specially equipped vehicle, A loading platform and a lifting mechanism for lifting and lowering the loading platform; an imaging device that captures images of the receiving platform and the surrounding area of ​​the receiving platform; an image processing device that performs image processing on the captured image captured by the imaging device, The image processing device includes: an area setting unit that sets a specific area in the captured image as a detection area based on the position or posture of the receiving platform; A loading platform lifting device comprising: a detection unit that performs predetermined image processing on the detection area within the captured image and detects objects other than the loading platform that appear in the detection area.

2. The loading platform lifting device according to claim 1 , wherein the area setting unit changes the detection area depending on the position or posture of the loading platform relative to the imaging device.

3. The loading platform lifting device according to claim 2 , wherein the area setting unit changes the position of the detection area depending on the position or attitude of the loading platform relative to the imaging device.

4. The loading platform lifting device according to claim 2 , wherein the area setting unit changes the area of ​​the detection area depending on the position or posture of the loading platform relative to the imaging device.

5. The loading platform lifting device according to claim 2 , wherein the area setting unit changes the shape of the detection area depending on the position or posture of the loading platform relative to the imaging device.

6. a height sensor for measuring the height of the loading platform; The loading platform lifting device according to claim 2 , wherein the area setting unit changes the detection area based on a measurement value of the height sensor.

7. The loading platform is rotatable between an upright position and a horizontal position, a tilt sensor for detecting a tilt angle of the loading platform relative to a horizontal plane; The loading platform lifting device according to claim 2 , wherein the area setting unit changes the detection area based on a measurement value of the tilt sensor.

8. The cargo receiving platform is provided so as to be retractable below the cargo box, a storage sensor for detecting whether the loading platform is stored below the loading box; The loading platform lifting device according to claim 2 , wherein the area setting unit changes the detection area based on the detection result of the storage sensor.

9. a control device for controlling the lifting mechanism; the area setting unit further sets a specific area within the detection area as a danger area where an object may come into contact with the receiving tray; The image processing device includes: an area determination unit that determines whether or not the object detected by the detection unit is located inside the danger area; an object discrimination unit that discriminates whether an object detected by the detection unit is a person or an obstacle based on a predetermined condition, 2. The loading platform lifting device of claim 1, wherein when the area discrimination unit determines that an object detected by the detection unit is present in the danger area and the object discrimination unit determines that the object detected by the detection unit is a person or an obstacle, the control device prohibits operation of the loading platform.

10. the area setting unit further sets a specific area within the detection area as a danger area where an object may come into contact with the receiving tray; The image processing device includes: an area determination unit that determines whether or not the object detected by the detection unit is located inside the danger area; an object discrimination unit that discriminates whether an object detected by the detection unit is a person or an obstacle based on a predetermined condition, The loading platform lifting device of claim 1, further comprising an alarm device that issues an alarm when the area discrimination unit determines that an object detected by the detection unit is present in the danger area and the object discrimination unit determines that the object detected by the detection unit is a person or an obstacle.

11. a control device that controls the lifting mechanism so that at least one of the position and the attitude of the loading platform changes over time from the start of operation; a timer that measures the time during which the control device operates the lifting mechanism, The loading platform lifting device according to claim 2 , wherein the area setting unit changes the detection area in accordance with a measurement value of the timer.

12. A specially equipped vehicle equipped with the loading platform lifting device according to any one of claims 1 to 11.

13. An object detection system for a loading platform lifting device including a loading platform and a lifting mechanism for lifting the loading platform, an imaging device that captures images of the receiving platform and the surrounding area of ​​the receiving platform; an image processing device that performs image processing on the captured image captured by the imaging device, The image processing device includes: an area setting unit that sets a specific area in the captured image as a detection area based on the position or posture of the receiving platform; An object detection system for a loading platform lifting device, comprising: a detection unit that performs predetermined image processing on the detection area within the captured image and detects objects other than the loading platform that appear in the detection area.

14. 14. The object detection system for a loading platform lifting device according to claim 13, wherein the captured image is displayed on a display device, and the detection area is displayed superimposed on the captured image.

Images