Work machine

Abstract

The present invention comprises: a front work machine that is provided at the front of a vehicle body; an operation cabin that is provided on a lateral side of the front work machine, which is at the front of the vehicle body; a front image capturing device that is provided in an upper portion of the operation cabin; a lateral image capturing device that is provided at a position on the vehicle body which is on the opposite side of the front work machine of the vehicle body from the position at which the front image capturing device is provided; a control device that generates a composite bird's-eye-view image on the basis of captured images; and a display device that is provided in the operation cabin and that displays the composite bird's-eye-view image, which is generated by the control device. The plurality of image capturing devices are disposed such that the image capturing ranges of adjacent image capturing devices overlap each other. The control device changes the position of the boundary between the image captured by the front image capturing device and the image captured by another image capturing device in the composite bird's-eye-view image, in accordance with the angle of rotation of the front work machine in the image captured by the front image capturing device. Thus, it is possible to generate a composite bird's-eye-view image on which the posture of the front work machine has little effect and which provides a wider field of view.

Description

Work machine

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

[0002] Work machines such as dump trucks and hydraulic excavators have a large vehicle body itself and are composed of many structures. For an operator boarding the cab, although the forward visibility is ensured, blind spots occur in the rear and left and right sides, creating areas that are difficult for the operator to visually observe. Therefore, for the purpose of assisting the visibility of areas that cannot be directly visually observed, a camera is installed on the work machine so that the surrounding of the vehicle body can be monitored, and the image is displayed on a monitor provided in the cab, developing a technology that indirectly allows the operator to recognize the situation around the vehicle body.

[0003] For example, Patent Document 1 discloses a display device for a self-propelled industrial machine, which includes a plurality of cameras with an optical axis obliquely downward for photographing the periphery of the self-propelled industrial machine, a viewpoint conversion unit for generating an aerial view image obtained by converting the viewpoint of each camera image taken by each camera to an overhead viewpoint, an image synthesis unit for synthesizing the aerial view image around a symbol image symbolizing the self-propelled industrial machine to generate a synthesized aerial view image, a direction overlapping unit for overlapping a front display unit indicating the direction in front of the symbol image on the symbol image, and a display device provided in the cab of the self-propelled industrial machine for displaying the synthesized aerial view image with the front display unit overlapped in an arbitrary direction.

[0004] Japanese Patent Application Laid-Open No. 2013-253426

[0005] By the way, a hydraulic excavator, which is an example of a work machine, has a lower traveling body having crawler-type or wheel-type traveling means and an upper revolving body that can revolve with respect to the lower revolving body. On the upper revolving body, a driver's seat and a front work implement for performing work are mounted. Generally, the cab is provided on the front left side of the upper revolving body, and the front work implement is provided in the front central part. Also, the front work implement is composed of a multi-articulated structure of a boom, an arm, and a bucket.

[0006] To generate a composite overhead view image, images looking down on the vehicle's surroundings are used. Therefore, cameras used for monitoring the vehicle's surroundings on a hydraulic excavator need to be mounted in relatively high locations. For example, the rear camera is mounted on the counterweight, the left and right cameras are mounted on the sides of the upper slewing body, and the front camera is mounted on the driver's cab or on rails fixed to the driver's cab. On the other hand, the front work implement is operated by the operator, and depending on the posture of the front work implement, it may protrude significantly forward from the upper slewing body, creating an area where the operator's view is obstructed. For example, with the front work implement lowered, the front right of the upper slewing body becomes a blind spot for the operator. The composite overhead view image, which is supposed to compensate for this blind spot, is largely obscured by the front work implement because the front camera is mounted above the driver's cab, leaving the blind spot and preventing it from adequately fulfilling its role as a visual aid.

[0007] The present invention has been made in view of the above, and aims to provide a work machine that can generate a composite overhead image that is less affected by the posture of the front work machine and provides a wider field of view.

[0008] The present invention includes several means for solving the above problems, but to give one example, a work machine comprising a vehicle body, a front work machine provided in front of the vehicle body, a driver's cab provided in front of the vehicle body and to the side of the front work machine, a plurality of imaging devices including a front imaging device provided above the driver's cab, a side imaging device provided on the vehicle body on the opposite side of the vehicle body from the position where the front imaging device is provided, a control device that generates a composite overhead image based on images taken by each of the plurality of imaging devices, and a display device provided in the driver's cab that displays the composite overhead image generated by the control device, wherein the plurality of imaging devices are arranged so that the shooting ranges of adjacent imaging devices overlap, and the control device changes the position of the boundary between the image taken by the front imaging device and the image taken by the other imaging devices in the composite overhead image according to the rotation angle of the front work machine in the image taken by the front imaging device.

[0009] According to the present invention, it is possible to generate a composite overhead image that is less affected by the posture of the front work equipment and provides a wider field of view.

[0010] This is a schematic side view showing the appearance of a hydraulic excavator, an example of a work machine. This is a schematic top view showing the appearance of a hydraulic excavator, an example of a work vehicle. This is a diagram showing the overall configuration of the surrounding monitoring system. This is a diagram showing the installation status of the imaging device. This is a diagram showing an example of a composite overhead image generated by the surrounding monitoring system and displayed on the display device. This is a diagram showing an example of objects being present around the vehicle body. This is a diagram showing an example of a composite overhead image in the positional relationship shown in Figure 6. This is a diagram showing an example of a composite overhead image when the boundary line is adjusted and changed. This is a diagram showing an example of a composite overhead image. This is a diagram showing an example of a composite overhead image.

[0011] Embodiments of the present invention will be described below with reference to the drawings.

[0012] In this embodiment, a hydraulic excavator is used as an example of a work machine, but the present invention can also be applied to other work machines that have a front work machine. In the following description, when there are multiple identical components, an alphabet letter may be added to the end of the reference numeral, but the alphabet letter may be omitted and the multiple components may be referred to collectively. That is, for example, when there are four imaging devices (front imaging device 17-F, right-side imaging device 17-R, left-side imaging device 17-L, and rear imaging device 17-B), these may be referred to collectively as imaging device 17. Also, for simplicity, the illustration may be omitted for signal lines and the like where the connection relationship is clear from the description.

[0013] <First Embodiment> A first embodiment of the present invention will be described with reference to Figures 1 to 8.

[0014] Figures 1 and 2 schematically show the external appearance of a hydraulic excavator, which is an example of a work machine according to this embodiment. Figure 1 is a side view, and Figure 2 is a top view.

[0015] In Figures 1 and 2, the hydraulic excavator 100 (working machine) comprises a vehicle body consisting of a lower traveling body 3 and an upper rotating body 4, and a multi-jointed front working machine 5 provided in front of the upper rotating body 4 that constitutes the vehicle body.

[0016] The lower vehicle 3 comprises a frame 31, tracks 32 wrapped around the frame 31 in the front-rear direction, and a hydraulic motor 6 that drives the tracks 32. The lower vehicle 3 is driven by the hydraulic motor 6, which is a hydraulic actuator.

[0017] The upper rotating body 4 is provided to be rotatable relative to the lower traveling body 3 and is driven to rotate by a rotating hydraulic motor 7, which is a hydraulic actuator.

[0018] The front work implement 5 is constructed by connecting a plurality of driven members (boom 8, arm 10, bucket 12 (work tool)) that rotate vertically. The base end of the boom 8 of the front work implement 5 is supported so as to be able to rotate vertically at the front of the upper slewing body 4, one end of the arm 10 is supported so as to be able to rotate vertically at an end (tip) different from the base end of the boom 8, and the bucket 12 is supported so as to be able to rotate vertically at the other end of the arm 10. The boom 8, arm 10, and bucket 12 are driven by hydraulic actuators, the boom cylinder 9, arm cylinder 11, and bucket cylinder 13, respectively.

[0019] In front of the upper rotating body 4 and to the side of the front work implement 5 (for example, to the left side), is the cab 18 (operator's cabin) where the operator of the hydraulic excavator 100 sits. In addition to the controller 19 (control device) that controls the overall operation of the hydraulic excavator 100, the upper rotating body 4 is also equipped with the prime mover, the engine 1, and the main pump 2 which is driven by the engine 1 to discharge hydraulic fluid.

[0020] The cab 18 is equipped with operating levers (not shown) for operating each of the hydraulic actuators 7, 9, 11, and 13, a controller 19 for controlling the overall operation of the hydraulic excavator 100, and a display device 20 such as a monitor for presenting and notifying the operator of various information. Although not shown, each operating lever can be tilted forward, backward, left, and right, and includes a detection device (not shown) that electrically detects the amount of tilt of the lever, i.e., the lever operation amount, which is the operation signal, and outputs the detected lever operation amount to the controller 19 via electrical wiring. In other words, the operation of the hydraulic actuators 7, 9, 11, and 13 is assigned to the forward / backward or left / right direction of the operating lever, respectively. Although not shown, the cab 18 is also equipped with a travel operation lever (travel pedal) for operating the travel hydraulic motor 6, and outputs the electrically detected lever operation amount of the travel operation lever to the controller 19 via electrical wiring. Note that the method is not limited to electrically detecting the lever operation amount, and the lever operation amount may also be realized by a hydraulic pilot system.

[0021] The operation of the boom cylinder 9, arm cylinder 11, bucket cylinder 13, slewing hydraulic motor 7, and left and right travel hydraulic motors 6 is controlled by controlling the direction and flow rate of the hydraulic fluid supplied from a hydraulic pump system (main pump 2), which is driven by a prime mover such as an engine 1 (or electric motor), to each hydraulic actuator 6, 7, 9, 11, and 13 using control valves. The control valves are operated by a controller 19 based on operation signals from the operating levers and travel operation levers, thereby controlling the operation of each hydraulic actuator 6, 7, 9, 11, and 13.

[0022] Attitude sensors 14, 15, and 16 (attitude detection devices) are attached to the base of the boom 8, the connection between the boom 8 and the arm 10, and the connection between the arm 10 and the bucket 12 (including the bucket link, etc.), respectively. The attitude sensors 14, 15, and 16 are mechanical angle sensors or rotation angle sensors, such as potentiometers, and detect the relative angles of the upper slewing body 4, boom 8, arm 10, and bucket 12, and output the detection results as attitude information to the controller 19.

[0023] In this embodiment, the example described uses angle sensors and rotation angle sensors as attitude sensors 14, 15, and 16 to detect the relative angles of the upper slewing body 4, boom 8, arm 10, and bucket 12, but the invention is not limited to this. For example, an inertial measurement unit (IMU) may be used as the attitude sensors 14, 15, and 16. Alternatively, stroke sensors may be placed on the boom cylinder 9, arm cylinder 11, and bucket cylinder 13, respectively, and the relative angles at each connection point of the upper slewing body 4, boom 8, arm 10, and bucket 12 may be determined from the stroke change.

[0024] The upper rotating body 4 is equipped with multiple (for example, four) imaging devices 17, such as cameras, that photograph the area around the hydraulic excavator 100. The imaging devices 17 include a forward imaging device 17-F, which is located on top of the cab 18 and photographs the area in front of the upper rotating body 4; a right-side imaging device 17-R, which is located on the opposite side (right side) from the forward imaging device 17-F, with the front work implement 5 of the upper rotating body 4 in between, and photographs the right side of the upper rotating body 4; a left-side imaging device 17-L, which is located on the left side of the upper rotating body 4 and photographs the left side of the upper rotating body 4; and a rear imaging device 17-B, which is located behind the upper rotating body 4 and photographs the area behind the upper rotating body. The multiple imaging devices 17 are arranged so that the shooting ranges of adjacent imaging devices 17 overlap, in other words, so that the ranges of the captured images overlap.

[0025] Figure 3 is a schematic diagram showing the overall configuration of the surrounding monitoring system.

[0026] The surrounding monitoring system according to this embodiment assists the operator's vision by, for example, displaying video (images) of the hydraulic excavator 100 and its surroundings on the display device 20 and presenting it to the operator. Figure 3 shows a controller 19 that has some of the functions of the surrounding monitoring system, along with its related components.

[0027] In Figure 3, the surrounding monitoring system is generally composed of a plurality of imaging devices 17 (forward imaging device 17-F, right-side imaging device 17-R, left-side imaging device 17-L, rear-side imaging device 17-B), a controller 19 that generates images (videos) taken by each imaging device 17, images obtained by transforming the viewpoint so that these images appear as if they were taken from vertically above (i.e., to have an overhead viewpoint), or images obtained by synthesizing the images taken by each imaging device 17 to obtain an overhead view of the vehicle and its surroundings from above the vehicle (hereinafter referred to as a composite overhead image 20a), and a display device 20 that displays the images (videos) generated by the controller 19.

[0028] The controller 19 includes, as a functional unit of the surrounding monitoring system, an image correction unit 21, a viewpoint conversion unit 22, an image synthesis unit 23, a symbol image storage unit 24, a front work machine position calculation unit 25, and a boundary setting unit 26.

[0029] The image correction unit 21 receives the camera image (through image) captured by the imaging device 17 and performs various image corrections such as lens distortion correction, aberration correction, contrast correction, and color tone correction based on camera optical system parameters, etc. This improves the image quality of the image input from the imaging device 17. The camera image corrected by the image correction unit 21 is output to the viewpoint conversion unit 22.

[0030] The viewpoint transformation unit 22 performs viewpoint transformation processing on the camera image input from the image correction unit 21 to generate an overhead view image (virtual viewpoint image) that looks as if it were taken from above.

[0031] Figure 4 shows the installation status of the imaging device.

[0032] As shown in Figure 4, each imaging device 17 has its optical axis oriented diagonally downward, and this is converted into a virtual viewpoint from above. The optical axis of the imaging device 17 is directed diagonally downward. Specifically, the optical axis A of the objective lens of the imaging device 17 (forward imaging device 17-F, rear imaging device 17-B, right-side imaging device 17-R, left-side imaging device 17-L) has a predetermined angle θ with respect to the ground surface G. The viewpoint conversion unit 22 virtually sets a virtual camera 17-V at a height H such that its optical axis direction is vertical, and converts the coordinates to image data as if this virtual camera 17-V were looking down at the ground surface G. The image converted into a viewpoint from above in this way becomes a virtual planar image (overhead view image).

[0033] Figure 5 shows an example of a composite overhead image generated by the surrounding monitoring system and displayed on the display device.

[0034] In the viewpoint conversion unit 22, a forward overhead view image 27-F, described later, is generated from the camera image of the forward imaging device 17-F, a rear overhead view image 27-B is generated from the camera image of the rear imaging device 17-B, a right-side overhead view image 27-R is generated from the camera image of the right-side imaging device 17-R, and a left-side overhead view image 27-L is generated from the camera image of the left-side imaging device 17-L. In this embodiment, the case using four imaging devices 17 has been explained as an example, but the number of imaging devices 17 can be set arbitrarily, so the number of overhead view images 27 generated will also change according to the number of imaging devices.

[0035] The symbol image storage unit 24 holds a symbol image 100a used in generating the composite overhead view image 20a in the image synthesis unit 23. The symbol image 100a is, for example, an image in which the hydraulic excavator 100 is used as a symbol (character), and is an image that reproduces the shape of the hydraulic excavator 100 as seen from directly above.

[0036] The front work implement position calculation unit 25 calculates the area in which the front work implement 5 exists in the camera image captured by the forward imaging device 17-F, determines whether the front work implement 5 is within a predetermined area, and outputs the determination result to the boundary setting unit 26. The controller 19's storage area (not shown) stores information related to the installation position and direction of the forward imaging device 17-F, the shooting range, design information of the hydraulic excavator 100 including the front work implement 5, and information on the area used for determination. Based on this information and information from the attitude sensors 14, 15, and 16 (i.e., the rotation angles of the boom 8, arm 10, and bucket 12 of the front work implement 5), the front work implement position calculation unit 25 calculates the positional relationship between the attitude of the front work implement 5 and the shooting range of the forward imaging device (or camera image), and calculates the area in which the front work implement 5 exists in the camera image captured by the forward imaging device 17-F. Furthermore, the system determines whether the area where the front work device 5 is located is within a predetermined area and outputs the determination result to the boundary setting unit 26.

[0037] In this embodiment, the front work implement position calculation unit 25 is shown as an example in which it calculates the area where the front work implement 5 is located in the camera image using information from the attitude sensors 14, 15, and 16, but the embodiment is not limited to this. For example, the camera image of the forward imaging device 17-F may be acquired, and the area where the front work implement 5 is located in the camera image may be identified by image recognition processing.

[0038] The boundary setting unit 26 selects from multiple candidates multiple (for example, four) boundary lines 37 to be used in generating the composite overhead image 20a in the image synthesis unit 23, based on the determination result from the front work machine position calculation unit 25. The boundary line setting may be configured to be set steplessly. In this embodiment, an example is given in which four boundary lines 37 are set as boundary lines 37 that divide the area where each overhead image 27 of the composite overhead image 20a is displayed. The multiple candidates for the boundary lines 37 are stored in a storage area (not shown) of the controller 19.

[0039] The image synthesis unit 23 receives the overhead images 27 whose viewpoints have been transformed by the viewpoint transformation unit 22 and the symbol image 100a held by the symbol image storage unit 24, and performs synthesis by placing the symbol image 100a in the center and arranging the overhead images 27 around it. In this embodiment, the synthesized overhead image 20a is generated by arranging the symbol image 100a in the center, with the front overhead image 27-F on the front side, the rear overhead image 27-B on the rear side, the right-side overhead image 27-R on the right side, and the left-side overhead image 27-L on the left side, and then synthesizing them.

[0040] In the composite overhead image 20a, a rectangular area with its longitudinal direction oriented front to back is used as the symbol area for displaying the symbol image 100a, and four boundary lines 37 (37-FR, 37-FL, 37-BR, 37-BL) are formed from its four corners to demarcate the areas for displaying each overhead image 27. The four boundary lines 37 are formed radially from the symbol area. The boundary lines 37 and the symbol area demarcate the areas for displaying each overhead image 27. The image synthesis unit 23 generates the composite overhead image 20a by compositing each overhead image 27 into each of the four areas demarcated by the boundary lines 37 and the symbol area. In other words, the composite overhead view image 20a is an image in which the symbol image 100a is at the center, with the front overhead view image 27-F positioned in front, the rear overhead view image 27-B positioned behind, the right-side overhead view image 27-R positioned to the right, and the left-side overhead view image 27-L positioned to the left. The composite overhead view image 20a generated by the image synthesis unit 23 is output to the display device 20. The boundary line 37 is set to be within the overlapping range of each overhead view image 27, so there is no area in the boundary line 37 of the composite overhead view image 20a where there is no overhead view image 27. The symbol image 100a is not limited to being set as a rectangular area, but may be other shapes such as an ellipse or a square.

[0041] The specific operation of generating a composite overhead image in the surrounding monitoring system configured as described above will now be explained.

[0042] Figure 6 is a schematic diagram illustrating an example of the presence of objects around a vehicle. Figure 7 is a diagram illustrating an example of a composite overhead view image with the positional relationship shown in Figure 6.

[0043] As shown in FIG. 6, depending on the posture of the front working machine 5, the right front of the upper swing body 4 may be a blind spot as viewed from the operator on board the cab 18. In this case, an object 28 (for example, a worker) will be present in the blind spot that has occurred in the right front of the upper swing body 4. At this time, since the front working machine 5 is also positioned between the front imaging device 17-F disposed above the cab 18 and the object 28, in the setting of the boundary line 37-FR as shown in FIG. 7, the front working machine 5 also appears large in the front overhead image 27-F using the video of the front imaging device 17-F, and the object 28 cannot be visually recognized on the composite overhead image 20a.

[0044] Therefore, in the present embodiment, according to the area where the front working machine 5 exists in the video (image) captured by the front imaging device 17-F, the position of the boundary between the front overhead image 27-F using the image captured by the front imaging device 17-F in the composite overhead image 20a and the image captured by another imaging device (here, the right side imaging device 17-R provided at a position opposite to the front imaging device 17-F with the front working machine 5 interposed therebetween) is adjusted and changed, so as to reduce the range of the blind spot caused by the front working machine 5 in the composite overhead image 20a, and generate a composite overhead image 20a with less influence of the posture of the front working machine 5 and a wider field of view.

[0045] Specifically, in the front working machine position calculation unit 25, the area where the front working machine 5 exists in the camera image captured by the front imaging device 17-F is calculated, and it is determined whether the front working machine 5 exists within a predetermined area. When the front working machine 5 exists in a predetermined area in the image captured by the front imaging device 17-F, in the boundary setting unit 26, the boundary line 37-FR between the front overhead image 27-F using the image captured by the front imaging device 17-F in the composite overhead image 20a and the right side overhead image 27-R using the image captured by another imaging device (here, the right side imaging device 17-R) is adjusted and changed. Here, the predetermined area is, for example, an area where a blind spot is considered to occur in the right front of the upper swing body 4 due to the front working machine 5, and is obtained experimentally in advance.

[0046] FIG. 8 is a diagram showing an example of a composite bird's-eye view image when the boundary line is adjusted / changed.

[0047] As shown in FIG. 8, when the front working machine 5 in the camera image captured by the front imaging device 17-F exists within a predetermined area, the section using the video of the front imaging device 17-F (front bird's-eye view image 27-F) is narrowed up to the extension line of the right side surface of the upper swing body 4 to reduce the display ratio of the front bird's-eye view image 27-F, and the section using the video of the right side imaging device 17-R (right side bird's-eye view image 27-R) is expanded up to the extension line of the right side surface of the upper swing body 4, and the boundary line 37-FR1 is selected and set. In this way, by changing the sections of the front bird's-eye view image 27-F by the front imaging device 17-F and the right side bird's-eye view image 27-R by the right side imaging device 17-R, the position of the object 28 can be displayed on the composite bird's-eye view image 20a without being in the blind spot of the front working machine 5. Since the front working machine 5 can be directly visually observed by the operator and does not need to be displayed on the composite bird's-eye view image 20a, even if the front working machine 5 is not displayed on the composite bird's-eye view image 20a or a partial image of the front working machine 5 is missing in the adjustment / change of the boundary line 37, no adverse effect occurs.

[0048] In addition, when the front working machine 5 in the camera image captured by the front imaging device 17-F exists within a predetermined area, that is, when it is assumed that no blind spot occurs in the right front of the upper swing body 4 by the front working machine 5, a standard boundary line 37-FR formed radially from the corner of the symbol area where the symbol image 100a is displayed is set (see FIG. 5).

[0049] The effects in the present embodiment configured as described above will be described.

[0050] The front work equipment is operated by the operator, and depending on its position, it may extend significantly forward from the upper slewing body, potentially obstructing the operator's view in certain areas. For example, with the front work equipment lowered, the area to the right front of the upper slewing body becomes a blind spot for the operator. The composite overhead view image, which is intended to compensate for this blind spot, is positioned with a forward camera above the driver's cab, so the front work equipment is prominently featured in the image, resulting in the blind spot persisting and potentially preventing the image from adequately assisting the operator's view.

[0051] Therefore, in this embodiment, the vehicle has a vehicle body having a lower traveling body 3 and an upper rotating body 4, a front work machine 5 provided in front of the upper rotating body 4, a cab 18 (driver's cabin) provided in front of the upper rotating body 4 and to the side of the front work machine 5, a plurality of imaging devices 17 including a forward imaging device 17-F provided on the upper part of the cab 18, and an imaging device (right-side imaging device 17-R) provided on the vehicle body on the opposite side of the position where the forward imaging device 17-F is provided, sandwiching the front work machine 5 of the upper rotating body 4, and a controller 19 (control device) that generates a composite overhead image 20a based on images taken by each of the plurality of imaging devices 17, and a controller provided in the cab 18 The system includes a display device 20 that displays the composite overhead image 20a generated by the imaging device 19, and the plurality of imaging devices 17 are arranged so that the shooting ranges of adjacent imaging devices 17 overlap. The controller 19 is configured to change the position of the boundary line 37 (boundary) between the front overhead image 27-F, which is made up of the image taken by the front imaging device 17-F, and the right-side overhead image 27-R, which is made up of the image taken by the right-side imaging device 17-R (another imaging device), in the composite overhead image 20a, according to the rotation angle of the front work equipment 5 in the image taken by the front imaging device 17-F. As a result, it is possible to generate a composite overhead image 20a that is less affected by the posture of the front work equipment 5 and provides a wider field of view.

[0052] In this embodiment, a cab 18 is provided in front of the upper rotating body 4 and to the left of the front work equipment 5. In the composite overhead view image 20a, the boundary line 37 between overhead view images 27-F and 27-R, which use the camera images of the forward imaging device 17-F provided on the top of the cab 18 and the right-side imaging device 17-R provided on the opposite side of the front imaging device 17-F with the front work equipment 5 in between, is adjusted and modified. However, the embodiment is not limited to this. For example, a cab may be provided in front of the upper rotating body 4 and to the right of the front work equipment 5. In the composite overhead view image, the boundary line between the overhead view images, which use the camera images of the forward imaging device provided on the top of the cab and the left-side imaging device provided on the opposite side of the front imaging device with the front work equipment in between, may be adjusted and modified.

[0053] <Modifications of the First Embodiment> Modifications of the first embodiment will be described with reference to Figures 9 and 10.

[0054] In the composite overhead view image 20a, if the boundary line 37 is aligned with the right side of the upper rotating body 4 (see Figure 8: boundary line 37-FR1), the right side of the upper rotating body 4 may be visible near the boundary line 37 between the right-side overhead view image 27-R from the right-side imaging device 17-R and the front-side overhead view image 27-F from the front-side imaging device 17-F. Therefore, to reduce this, for example, as shown in Figure 9, the boundary line 37-FR2 may be set in the composite overhead view image 20a at an angle to a certain amount outward from the extension of the right side of the upper rotating body 4, or, as shown in Figure 10, the boundary line 37-FR3 may be set by moving it parallel to the right side of the upper rotating body 4 by a certain amount (for example, width W) outward. In the case of Figure 10, the symbol image 100a is enlarged by the amount by which the boundary line 37 has been moved.

[0055] <Note> The present invention is not limited to the embodiments described above, and includes various modifications and combinations that do not depart from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and includes those in which some of the configurations have been omitted. In addition, some or all of the above configurations, functions, etc. may be realized by designing, for example, an integrated circuit. Furthermore, each of the above configurations, functions, etc. may be realized in software by having a processor interpret and execute a program that realizes each function.

[0056] 1...Engine, 2...Main pump, 3...Lower traveling body, 4...Upper slewing body, 5...Front work implement, 6...Travel hydraulic motor, 7...Slewing hydraulic motor, 8...Boom, 9...Boom cylinder, 10...Arm, 11...Arm cylinder, 12...Bucket, 13...Bucket cylinder, 14, 15, 16...Attitude sensors, 17-B...Rear imaging device, 17-F...Forward imaging device, 17-L...Left side imaging device, 17-R...Right side imaging device, 17-V...Virtual camera, 18...Cab, 19...Controller, 20...Display device, 20a...Composite overhead view image, 21...Image correction unit, 22...Viewpoint conversion unit, 23...Image synthesis unit, 24...Symbol image storage unit, 25...Front work machine position calculation unit, 26...Boundary setting unit, 27-B...Rear overhead view image, 27-F...Front overhead view image, 27-L...Left overhead view image, 27-R...Right overhead view image, 28...Object, 31...Frame, 32...Track, 37-BL, 37-BR, 37-FL, 37-FR, 37-FR1, 37-FR2, 37-FR3...Boundary line, 100...Hydraulic excavator, 100a...Symbol image

Claims

1. A work machine comprising: a vehicle body; a front work machine provided in front of the vehicle body; a driver's cab provided in front of the vehicle body and to the side of the front work machine; a plurality of imaging devices including a forward imaging device provided above the driver's cab and a side imaging device provided on the vehicle body on the opposite side of the vehicle body from where the forward imaging device is provided, sandwiching the front work machine; a control device that generates a composite overhead image based on images taken by each of the plurality of imaging devices; and a display device provided in the driver's cab that displays the composite overhead image generated by the control device, wherein the plurality of imaging devices are arranged such that the shooting ranges of adjacent imaging devices overlap, and the control device changes the position of the boundary between the image taken by the forward imaging device and the image taken by the other imaging devices in the composite overhead image according to the rotation angle of the front work machine.

2. The work machine according to claim 1, wherein the control device adjusts the position of the boundary between the image captured by the forward imaging device and the image captured by the other imaging device in the composite overhead view image such that the display area of ​​the image captured by the other imaging device expands towards the image captured by the forward imaging device, thereby reducing the display ratio of the image captured by the forward imaging device.

3. The work machine according to claim 1, characterized in that the change in the position of the boundary between the image captured by the forward imaging device and the image captured by the other imaging device in the composite overhead view image is performed within the overlapping range of the image captured by the forward imaging device and the image captured by the side imaging device.

4. The work machine according to claim 1, characterized in that the side imaging device is positioned on the right side of the vehicle body.

5. A work machine according to claim 2, comprising a posture detection device for detecting the posture of the front work machine, wherein the control device determines, based on the detection result of the posture detection device, whether or not the front work machine is present in a predetermined area in the image captured by the forward imaging device.

6. The work machine according to claim 2, wherein the control device determines whether or not the front work machine is present in a predetermined area by image recognition of an image captured by the forward imaging device.

7. The work machine according to claim 2, wherein the control device offsets the boundary line indicating the boundary between the image captured by the front imaging device and the image captured by the side imaging device in the composite overhead view image by a predetermined amount to the right, and enlarges the symbol image corresponding to the vehicle body displayed in the center of the composite overhead view image by the amount of the predetermined offset.

Images