Road machinery

Abstract

To provide an asphalt finisher capable of more appropriately controlling an expansion and contraction amount of a screed.SOLUTION: An asphalt finisher 100 includes a tractor 1, a hopper 2 installed on the front side of the tractor 1 for receiving a pavement material PV, a conveyor CV for conveying the pavement material PV in the hopper 2 to the rear side of the tractor 1, a screw SC for spreading on the rear side of the tractor 1 the pavement material PV conveyed by the conveyor CV, a screed 3 for evenly leveling the pavement material PV spread by the screw SC on the rear side of the screw SC, and a controller 50 which calculates, on the basis of information related to a planimetric feature defining a boundary line of a road of a construction object positioned ahead of the screed 3, a coordinate on the boundary line in a prescribed coordinate system.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to road machinery. [Background technology]

[0002] Conventionally, an asphalt finisher is known that uses a semiconductor laser projector and a CCD camera attached to the end of the screed to detect the boundary line of the road to be paved, and then extends or retracts the screed to match that boundary line (see Patent Document 1).

[0003] This asphalt finisher is configured to extend and retract the screed so that the distance between the end of the screed and the boundary line in the vehicle width direction becomes smaller. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-294105 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned asphalt finisher recognizes that there is a gap between the end of the screed and the boundary line in the vehicle width direction, and then extends or retracts the screed to reduce the gap. Therefore, the above-mentioned asphalt finisher may not be able to quickly respond to changes in the direction of the boundary line.

[0006] Therefore, it is desirable to provide road machinery such as an asphalt finisher that can more appropriately control the amount of expansion and contraction of the screed by recognizing changes in the direction of the boundary line before the screed reaches areas where the direction of the boundary line changes, such as areas where the road (construction width) is widened. [Means for solving the problem]

[0007] A road machinery according to an embodiment of the present disclosure is a road machinery comprising: a tractor; a hopper installed in front of the tractor to receive paving material; a conveyor that feeds the paving material in the hopper to the rear of the tractor; a screw that spreads the paving material fed by the conveyor behind the tractor; a screed that evens out the paving material spread by the screw behind the screw; an object detection device that acquires information about features that define the boundary line of a construction area located in front of the screed; and a control device that calculates coordinates on the boundary line in a predetermined coordinate system based on the information acquired by the object detection device, wherein the object detection device: It is attached to a part other than the screed in the road machine, or to a moving body other than the road machine, The screed is disposed forward and includes at least one of a left object detection device that monitors the ground on the left side of the road machine and a right object detection device that monitors the ground on the right side of the road machine, and the range monitored by the object detection device is: The construction target area located forward of the screed The left-right width of the range that includes the boundary line and is monitored by the object detection device is smaller than the left-right width of the construction target range. [Effects of the Invention]

[0008] The road machine described above can use coordinates on the boundary line located ahead of the screed, allowing better control of the amount of extension and contraction of the screed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a side view of the asphalt finisher. [Figure 2] FIG. 2 is a top view of the asphalt finisher. [Figure 3] FIG. 1 is a diagram illustrating an example of the configuration of an operation support system. [Figure 4] FIG. 2 is a schematic perspective view of a paving formwork. [Figure 5] 10 is a flowchart showing an example of the flow of a goal setting process. DETAILED DESCRIPTION OF THE INVENTION

[0010] Fig. 1 is a side view of an asphalt finisher 100, which is an example of a road machine according to an embodiment of the present disclosure. Fig. 2 is a top view of the asphalt finisher 100. In the illustrated example, the asphalt finisher 100 is a wheel-type asphalt finisher, and is mainly composed of a tractor 1, a hopper 2, and a screed 3. In the following, the direction of the hopper 2 as seen from the tractor 1 (+X direction) is defined as the front, and the direction of the screed 3 as seen from the tractor 1 (-X direction) is defined as the rear.

[0011] The tractor 1 is a mechanism for moving the asphalt finisher 100. In the illustrated example, the tractor 1 rotates the rear wheels 5 using a rear-wheel drive hydraulic motor and rotates the front wheels 6 using a front-wheel drive hydraulic motor to move the asphalt finisher 100. The rear-wheel drive hydraulic motor and the front-wheel drive hydraulic motor are rotated by receiving a supply of hydraulic oil from a hydraulic pump. However, the front wheels 6 may be driven wheels.

[0012] The asphalt paver 100 may be a crawler type asphalt paver. In this case, the combination of the rear wheels 5 and the front wheels 6 is replaced with a combination of a left crawler and a right crawler.

[0013] The hopper 2 is a mechanism for receiving the paving material PV. In the illustrated example, the hopper 2 is installed in front of the tractor 1 and is configured to be able to open and close in the vehicle width direction (Y-axis direction) using a hopper cylinder. The asphalt finisher 100 typically receives the paving material PV (e.g., asphalt mixture) from the bed of a dump truck when the hopper 2 is fully open. A dump truck is an example of a transport vehicle that transports the paving material PV. Figures 1 and 2 show the hopper 2 in its fully open state. As the paving material PV in the hopper 2 decreases during construction, the operator of the asphalt finisher 100 closes the hopper 2 to collect the paving material PV near the inner wall of the hopper 2 in the center of the hopper 2. This is so that the conveyor CV located in the center of the hopper 2 can feed the paving material PV to the rear of the tractor 1. The paving material PV fed to the rear of the tractor 1 by the conveyor CV is spread in the vehicle width direction by the screw SC behind the tractor 1 and in front of the screed 3. In the illustrated example, the screw SC is connected to the left extension screw SCL and the right extension screw SCR. For clarity, the paving material PV in the hopper 2 is not shown in Figures 1 and 2, and the paving material PV spread by the screw SC is shown with a coarse dot pattern, while the new pavement NP laid and leveled by the screed 3 is shown with a fine dot pattern.

[0014] The screed 3 is a mechanism for spreading and leveling the paving material PV. In the illustrated example, the screed 3 includes a front screed 30 and a rear screed 31. The front screed 30 includes a left front screed 30L and a right front screed 30R. The rear screed 31 is a screed that is extendable and retractable in the vehicle width direction and includes a left rear screed 31L and a right rear screed 31R. Specifically, the rear screed 31 is extended and retracted by a screed telescopic cylinder 7 installed within the screed 3. More specifically, the screed telescopic cylinder 7 includes a left screed telescopic cylinder 7L and a right screed telescopic cylinder 7R. The left rear screed 31L is extended and retracted by the left screed telescopic cylinder 7L, and the right rear screed 31R is extended and retracted by the right screed telescopic cylinder 7R.

[0015] The screed 3 is a floating screed towed by the tractor 1 and is connected to the tractor 1 via a leveling arm 3A. The leveling arm 3A includes a left leveling arm 3AL disposed on the left side of the tractor 1 and a right leveling arm 3AR disposed on the right side of the tractor 1. An end leveling device may be disposed at the end of the rear screed 31.

[0016] A side plate 41 is attached to the distal end of the rear screed 31. In the illustrated example, a left side plate 41L is attached to the left end of the left rear screed 31L, and a right side plate 41R is attached to the right end of the right rear screed 31R.

[0017] A tread 32 is attached to the rear of the screed 3. Specifically, the tread 32 is attached to the rear of the screed 3 so that workers can move back and forth in the vehicle width direction behind the screed 3 without stepping on the new pavement NP. In the illustrated example, the treads 32 include a central tread 32C attached to the rear of the front screed 30, a left tread 32L attached to the rear of the left rear screed 31L, and a right tread 32R attached to the rear of the right rear screed 31R.

[0018] A moldboard 42 is attached to the front of the screed 3. The moldboard 42 is configured to adjust the amount of paving material PV that accumulates in front of the screed 3. The paving material PV passes through the gap between the lower end of the moldboard 42 and the roadbed BS and reaches underneath the screed 3. In the illustrated example, the moldboard 42 includes a left moldboard 42L that is positioned in front of the left rear screed 31L, and a right moldboard 42R that is positioned in front of the right rear screed 31R.

[0019] The screw SC is disposed in front of the moldboard 42, and the retaining plate 43 is disposed in front of the screw SC. Specifically, the retaining plate 43 includes a left retaining plate 43L disposed in front of the left extension screw SCL, and a right retaining plate 43R disposed in front of the right extension screw SCR. Note that the retaining plate 43 may be omitted.

[0020] The tractor 1 is equipped with a traveling speed sensor S1, a controller 50, an object detection device 51, an on-board display device 52, a steering device 53, and a screed extension / retraction device 54.

[0021] The traveling speed sensor S1 is configured to detect the traveling speed of the asphalt finisher 100. In the illustrated example, the traveling speed sensor S1 is a wheel speed sensor, and is configured to detect the rotational angular velocity and rotation angle of the rear wheels 5, and therefore the traveling speed and traveling distance of the asphalt finisher 100.

[0022] The controller 50 is a control device that controls the asphalt finisher 100. In the illustrated example, the controller 50 is configured with a microcomputer including a CPU, a volatile storage device, a non-volatile storage device, etc. Each function of the controller 50 is realized by the CPU executing a program stored in the non-volatile storage device. However, each function of the controller 50 may be realized not only by software, but also by hardware, or may be realized by a combination of hardware and software.

[0023] The object detection device 51 is configured to acquire information about features within a predetermined range of the road to be constructed, and output the acquired information to the controller 50. In other words, the object detection device 51 is configured to monitor a predetermined range of the road to be constructed. The predetermined range on the road is, for example, an area located forward of the screed 3 and including the road boundary line. In the illustrated example, the predetermined range on the road is an area having a front-to-back width and left-to-right width that are greater than the width of the paving formwork, for example, an area of ​​2 meters square.

[0024] The range located forward of the screed 3 is, for example, a range located forward of the hopper 2, a range located forward of the axle of the front wheels 6, a range located forward of the axle of the rear wheels 5, a range located forward of the screw SC, etc.

[0025] The features within the specified range include, for example, the roadbed BS and an object AP located outside the roadbed BS. The object AP is a feature used to determine the position of the widthwise edge of the pavement to be laid. In the example shown in Figures 1 and 2, the object AP is a paving formwork having a specified thickness (height), and includes a left object APL located on the left side of the asphalt finisher 100 and a right object APR located on the right side of the asphalt finisher 100. Specifically, the left object APL includes a first left object APL1 and a second left object APL2, and the right object APR includes a first right object APR1 and a second right object APR2. The object AP may be an L-shaped gutter block, a curb block, or a cut-out step of an existing pavement. The cut-out step of an existing pavement refers to a step between the surface of the cut portion and the surface of the uncut portion formed when cutting the old pavement to lay a new pavement. The object AP may be a feature with almost no thickness, such as a line drawn on the ground, tape stuck to the ground, or string stretched along the ground. Information about the feature includes, for example, the height of the feature, the color of the surface of the feature, or the reflectance of the surface of the feature. Note that the left object APL is not shown in FIG. 1 for clarity.

[0026] In the illustrated example, the object detection device 51 is a stereo camera configured to be able to monitor a predetermined range. Note that the object detection device 51 may also be a monocular camera configured to be able to monitor a predetermined range, a LIDAR, a millimeter wave radar, a laser radar, a laser scanner, a distance imaging camera, a laser range finder, an ultrasonic sensor, or a combination thereof.

[0027] Furthermore, the stereo camera serving as object detection device 51 is preferably configured to have an automatic exposure adjustment function. With this configuration, object detection device 51 can acquire information about features within a predetermined range regardless of day or night, i.e., without the need for special lighting or the like.

[0028] In the illustrated example, the object detection device 51 includes a left object detection device 51L installed on the left side of the asphalt finisher 100 and a right object detection device 51R installed on the right side of the asphalt finisher 100.

[0029] The left object detection device 51L is configured to be able to monitor the ground on the left side of the asphalt finisher 100. In the illustrated example, the left object detection device 51L is a stereo camera that monitors a left monitoring range ZL (the range surrounded by a dashed line in FIG. 2) on the ground on the left side of the asphalt finisher 100.

[0030] The right object detection device 51R is configured to be able to monitor the ground to the right of the asphalt finisher 100. In the illustrated example, the right object detection device 51R is a stereo camera that monitors a right monitoring range ZR (the range surrounded by a dashed line in FIG. 2) on the ground to the right of the asphalt finisher 100.

[0031] The object detection device 51 may be attached to the asphalt finisher 100 via an attachment member 60. The attachment member 60 is a member used to attach the object detection device 51 to the asphalt finisher 100. In the illustrated example, the attachment member 60 includes a left attachment member 60L and a right attachment member 60R. In the example shown in FIG. 2, the left object detection device 51L is attached to the left front end of the tractor 1 via the left attachment member 60L, and the right object detection device 51R is attached to the right front end of the tractor 1 via the right attachment member 60R. Note that the left object detection device 51L may be attached to another portion of the asphalt finisher 100, such as the left front end of the hopper 2, via the left attachment member 60L. Similarly, the right object detection device 51R may be attached to another portion of the asphalt finisher 100, such as the right front end of the hopper 2, via the right attachment member 60R.

[0032] The object detection device 51 may also be configured to be able to monitor the extension / retraction state of the rear screed 31. For example, the object detection device 51 may additionally include a stereo camera configured to be able to monitor the end of the left rear screed 31L and a stereo camera configured to be able to monitor the end of the right rear screed 31R. In this case, the object detection device 51 may be arranged on the screed 3. For example, the object detection device 51 may be arranged on the rear screed 31. Furthermore, if an end paving / leveling device is arranged at the end of the rear screed 31, the object detection device 51 may also be arranged on the end paving / leveling device.

[0033] In the example shown in FIG. 2, the object detection device 51 is attached to the attachment member 60 so as to face vertically downward, but it may also be attached to the attachment member 60 so as to face in another direction, such as diagonally downward.

[0034] In the example shown in Fig. 2, the left attachment member 60L is composed of an expandable member TA that is expandable in the width direction and a pivoting member SB that is pivotally connected to the distal end of the expandable member TA. The pivoting member SBa, represented by a dashed line in Fig. 2, indicates the state when the pivoting member SB is rotated. The same applies to the right attachment member 60R.

[0035] In this way, the mounting member 60 is configured so that the monitoring range of the object detection device 51 can be moved by the extendable member TA and the pivoting member SB. This is to allow for changes in pavement width, etc. In this case, the controller 50 may be configured to control the extension and contraction of the extendable member TA so that the object detection device 51 follows the object AP. This allows the controller 50 to ensure that the object AP is continuously included in the monitoring range of the object detection device 51 even if the position of the object AP changes in the vehicle width direction.

[0036] The attachment member 60 may include at least one of a sensor that detects the amount of expansion and contraction of the expandable member TA and a sensor that detects the amount of rotation (rotation angle) of the rotating member SB.

[0037] At least one of the telescopic member TA and the rotating member SB may be omitted. For example, the mounting member 60 may be configured to be non-telescopic and non-rotatable. That is, the mounting member 60 may be a rod-shaped member that is non-telescopic and non-rotatable.

[0038] Furthermore, the object detection device 51 may be attached directly to the asphalt finisher 100 without using the attachment member 60.

[0039] Furthermore, the object detection device 51 may be configured as a single device that can simultaneously monitor the ground on the left side of the asphalt finisher 100 and the ground on the right side of the asphalt finisher 100. Specifically, the object detection device 51 may be configured as a single device that can simultaneously monitor the left object APL and the right object APR. In this case, the object detection device 51 may be attached to the center of the front end of the top surface of the tractor 1.

[0040] In addition, the asphalt finisher 100 may be equipped with a steering angle sensor configured to detect the steering angle of the asphalt finisher 100, and a screed expansion / contraction amount sensor configured to detect the expansion / contraction amount of the rear screed 31.

[0041] The on-board display device 52 is configured to be able to display information related to the asphalt finisher 100. In the illustrated example, the on-board display device 52 is a liquid crystal display installed in front of the driver's seat 1S. However, the on-board display device 52 may also include a display device installed on at least one of the left end and right end of the screed 3.

[0042] The steering device 53 is configured to steer the asphalt paving machine 100. In the illustrated example, the steering device 53 is configured to extend and retract a front wheel steering cylinder installed near the front axle. Specifically, the steering device 53 includes a steering electromagnetic control valve that controls the flow rate of hydraulic oil flowing from a hydraulic pump to the front wheel steering cylinder and the flow rate of hydraulic oil discharged from the front wheel steering cylinder. The steering electromagnetic control valve is configured to control the flow of hydraulic oil in and out of the front wheel steering cylinder in response to the rotation of a steering wheel SH (handle) serving as an operating device. Note that the steering electromagnetic control valve may be configured to control the flow of hydraulic oil in and out of the front wheel steering cylinder in response to the operation of an input switch, which is an operating device separate from the steering wheel SH, regardless of the movement of the steering wheel SH. Furthermore, the steering electromagnetic control valve may be configured to control the flow of hydraulic oil in and out of the front wheel steering cylinder in response to a steering command from the controller 50, regardless of the rotation of the steering wheel SH. That is, the controller 50 may be configured to automatically steer the asphalt finisher 100 regardless of whether or not the driver operates the steering wheel SH.

[0043] If the asphalt finisher 100 is a crawler-type asphalt finisher, the steering device 53 is configured to be able to separately control the pair of left and right crawlers. Note that instead of a steering wheel SH, a crawler-type asphalt finisher has a left operating lever, which is an operating device for operating the left crawler, and a right operating lever, which is an operating device for operating the right crawler.

[0044] Specifically, the steering device 53 includes a left steering electromagnetic control valve that controls the flow rate of hydraulic oil flowing from the hydraulic pump to a left traveling hydraulic motor for rotating the left crawler, and a right steering electromagnetic control valve that controls the flow rate of hydraulic oil flowing from the hydraulic pump to a right traveling hydraulic motor for rotating the right crawler. The left steering electromagnetic control valve is configured to control the inflow and outflow of hydraulic oil to the left traveling hydraulic motor in accordance with the operation amount (tilt angle) of the left operating lever. Similarly, the right steering electromagnetic control valve is configured to control the inflow and outflow of hydraulic oil to the right traveling hydraulic motor in accordance with the operation amount (tilt angle) of the right operating lever. Note that the left steering electromagnetic control valve may be configured to control the inflow and outflow of hydraulic oil to the left traveling hydraulic motor in accordance with a steering command from the controller 50, regardless of whether the left operating lever is operated by the driver. Similarly, the right steering electromagnetic control valve may be configured to control the flow of hydraulic oil in and out of the right traveling hydraulic motor in response to a steering command from the controller 50, regardless of whether the driver operates the right operating lever.

[0045] The screed extension / retraction device 54 is configured to extend and retract the rear screed 31 in the vehicle width direction (Y-axis direction). In the illustrated example, the screed extension / retraction device 54 is configured to extend and retract the screed telescopic cylinder 7 installed inside the screed 3. Specifically, the screed extension / retraction device 54 includes a screed extension / retraction electromagnetic control valve that controls the flow rate of hydraulic oil flowing from the hydraulic pump to the screed telescopic cylinder 7 and the flow rate of hydraulic oil discharged from the screed telescopic cylinder 7. The screed extension / retraction electromagnetic control valve is configured to control the flow of hydraulic oil in and out of the screed telescopic cylinder 7 in response to operation of a telescopic button set (not shown) serving as an operating device provided near the on-board display device 52. The telescopic button set typically includes a left telescopic button set for extending and retracting the left rear screed 31L and a right telescopic button set for extending and retracting the right rear screed 31R. The screed extension / retraction electromagnetic control valve may be configured to control the flow of hydraulic oil in and out of the screed telescopic cylinder 7 in response to an extension / retraction command from the controller 50, regardless of operation of the telescopic button set. That is, the controller 50 may be configured to automatically extend and retract the rear screed 31 regardless of whether or not the operator operates the extension / retraction button set.

[0046] Specifically, the screed extension / retraction device 54 includes a left telescopic electromagnetic control valve that controls the flow rate of hydraulic oil from the hydraulic pump to the left screed telescopic cylinder 7L for extending and retracting the left rear screed 31L, and a right telescopic electromagnetic control valve that controls the flow rate of hydraulic oil from the hydraulic pump to the right screed telescopic cylinder 7R for extending and retracting the right rear screed 31R. The left telescopic electromagnetic control valve is configured to control the flow of hydraulic oil in and out of the left screed telescopic cylinder 7L in response to the operation of the left telescopic button set. Similarly, the right telescopic electromagnetic control valve is configured to control the flow of hydraulic oil in and out of the right screed telescopic cylinder 7R in response to the operation of the right telescopic button set. Note that the left telescopic electromagnetic control valve may be configured to control the flow of hydraulic oil in and out of the left screed telescopic cylinder 7L in response to an extension / retraction command from the controller 50, regardless of whether the operator operates the left telescopic button set. Similarly, the right telescopic electromagnetic control valve may be configured to control the flow of hydraulic oil in and out of the right screed telescopic cylinder 7R in response to a telescopic command from the controller 50, regardless of whether the operator operates the right telescopic button set.

[0047] Next, an example of the configuration of the operation support system DS mounted on the asphalt finisher 100 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the configuration of the operation support system DS.

[0048] The operation support system DS is mainly composed of a controller 50, a left object detection device 51L, a right object detection device 51R, a traveling speed sensor S1, an in-vehicle display device 52, a steering device 53, and a screed extension / retraction device 54.

[0049] In the example shown in FIG. 3, the controller 50 includes a coordinate calculation unit 50a, a steering control unit 50b, and a screed extension / retraction control unit 50c.

[0050] The coordinate calculation unit 50a is configured to calculate coordinates on the boundary line of the construction area based on information about the features acquired by the object detection device 51. The guide line GD shown by the thick dashed line in FIG. 2 is an example of the boundary line of the road to be constructed and is a virtual line representing a guide surface. The guide surface is a virtual surface recognized as a surface with which the widthwise end face of the pavement to be laid should be aligned. In the example shown in FIG. 2, the guide line GD includes a left guide line GDL representing the left guide surface with which the left end face of the new pavement NP should be aligned, and a right guide line GDR representing the right guide surface with which the right end face of the new pavement NP should be aligned.

[0051] Specifically, the coordinate calculation unit 50a calculates coordinates on the guide line GD based on information about the object AP acquired by the object detection device 51. More specifically, the coordinate calculation unit 50a calculates the coordinates of a point VL constituting the left guide line GDL based on information about the left object APL acquired by the left object detection device 51L, and calculates the coordinates of a point VR constituting the right guide line GDR based on information about the right object APR acquired by the right object detection device 51R.

[0052] For example, as shown in FIG. 4, the coordinate calculation unit 50a uses image recognition technology to generate a right guide line GDR so that the virtual line representing the angle (edge) between the left end face LE and the upper end face UE of the right object APR within the right monitoring range ZR of the right object detection device 51R becomes the right guide line GDR. The coordinate calculation unit 50a then calculates the coordinates of the intersection of the generated right guide line GDR and the transverse line TL as the coordinates of point VR. In the example shown in FIG. 4, the transverse line TL is a straight line that is parallel to the vehicle width direction (Y-axis direction) and intersects with the center line (optical axis OA) of the right object detection device 51R. Note that FIG. 4 is a schematic perspective view of a paving formwork serving as the right object APR as seen from behind the asphalt finisher 100, and schematically illustrates the positional relationship between the right object detection device 51R and the right object APR.

[0053] For example, the coordinate calculation unit 50a uses a distance image of the right monitoring range ZR generated based on the output of a stereo camera serving as the right object detection device 51R to calculate the coordinates of a pixel including the intersection of the right guide line GDR and the transverse line TL as the coordinates of a point VR. The distance image is a data set in which each pixel value of a two-dimensional array of pixels is represented by the distance from the right object detection device 51R.

[0054] The coordinates of point VR are one coordinate in a predetermined coordinate system. The predetermined coordinate system is, for example, the World Geodetic System. The World Geodetic System is a three-dimensional Cartesian XYZ coordinate system with its origin at the center of gravity of the Earth, its X axis pointing in the direction of the intersection of the Greenwich Meridian and the equator, its Y axis pointing in the direction of 90 degrees east longitude, and its Z axis pointing in the direction of the North Pole. However, the predetermined coordinate system may also be a local coordinate system whose origin is a predetermined point on the asphalt finisher 100. In other words, the predetermined coordinate system may be a local coordinate system whose origin moves as the asphalt finisher 100 moves. Specifically, the predetermined coordinate system may be, for example, a three-dimensional Cartesian coordinate system whose origin is the center point of the asphalt finisher 100. In this case, the center point of the asphalt finisher 100 may be, for example, the center point of the tractor 1 or the intersection of the axle of the rear wheels 5 and the front-rear axis AX (see FIG. 2). The predetermined coordinate system may also be a local coordinate system whose origin does not move even when the asphalt finisher 100 moves. In this case, the local coordinate system may be a coordinate system whose origin is the center point of the asphalt finisher 100 at the start of construction. The predetermined coordinate system may also be a plane rectangular coordinate system such as a surveying plane coordinate system used in a total station or the like.

[0055] The coordinate calculation unit 50a may be configured to extract pixels that make up the distance image and whose difference from the pixel value of the pixel to the left is equal to or greater than a predetermined threshold, and derive a single line as the guide line GD from the arrangement of the extracted pixels. The single line may be a straight line, a curved line, or a combination thereof. Any image recognition technology, such as a Hough transform, may be used to derive the single line.

[0056] The coordinate calculation unit 50a may eliminate the influence of variations in the positions of the extracted pixels by performing an averaging process. Specifically, such variations may occur in image portions corresponding to the contact points between two paving forms or irregularities in the cutting steps.

[0057] In this example, the predetermined threshold value is a threshold value TH related to the height of the paving formwork. In this case, the coordinate calculation unit 50a can generate, as the right guide line GDR, a virtual line representing the upper left edge of the right object APR, which is a paving formwork having a height H1 equal to or greater than the threshold value TH, as shown in FIG.

[0058] The threshold value TH may be configured to be set in advance to match the height of the paving formwork that will actually be used. Using a threshold value TH set to match the height of the paving formwork that will actually be used enables the generation of guide lines based on the edges of thin paving formwork. Furthermore, using a threshold value TH set to match the height of the paving formwork that will actually be used prevents the coordinate calculation unit 50a from erroneously generating guide lines based on the shape (edge) of features other than the paving formwork.

[0059] Thereafter, the coordinate calculation unit 50a calculates the coordinates of the intersection point between the generated right guide line GDR and the transverse line TL as the coordinates of the point VR, as shown in FIG.

[0060] Note that the above explanation relates to the process of calculating the coordinates of point VR on the right guide line GDR from the distance image related to the right monitoring range ZR, but it also applies to the process of calculating the coordinates of point VL on the left guide line GDL from the distance image related to the left monitoring range ZL.

[0061] Furthermore, if the object detection device 51 is a monocular camera, the "distance image" in the above description can be read as "image." In this case, the "pixel value" is represented by color information or the like, rather than distance. The color information may be brightness.

[0062] In this way, the coordinate calculation unit 50a continuously calculates and stores the coordinates of each of the points VL and VR. In the illustrated example, the coordinate calculation unit 50a is configured to calculate and store the coordinates of each of the points VL and VR every time the asphalt finisher 100 moves forward a predetermined distance (for example, 15 cm). Note that the coordinate calculation unit 50a may also be configured to calculate and store the coordinates of each of the points VL and VR every time a predetermined time has elapsed.

[0063] FIG. 1 shows how the coordinate calculation unit 50a continuously calculates and stores the coordinates of point VL. In FIG. 1, point VL0 corresponds to point VL derived by the coordinate calculation unit 50a based on the output of left object detection device 51L at the current time. Point VL1 corresponds to point VL derived by the coordinate calculation unit 50a based on the output of left object detection device 51L at a point in the past. The same applies to points VL2 to VL4. Point VL11 corresponds to point VL derived by the coordinate calculation unit 50a based on the output of left object detection device 51L at a point in the future. The same applies to points VL12 to VL14. That is, at the current time, the coordinate calculation unit 50a has already calculated and stored the coordinate values ​​of point VL0 and points VL1 to VL4.

[0064] Like FIG. 1, FIG. 2 also shows how the coordinate calculation unit 50a intermittently calculates and stores the coordinates of points VL and VR. In FIG. 2, point VR0 corresponds to point VR derived by the coordinate calculation unit 50a based on the output of right object detection device 51R at the current time. The same applies to point VL0. Point VR1 corresponds to point VR derived by the coordinate calculation unit 50a based on the output of right object detection device 51R at a point in the past. The same applies to points VR2 to VR4. Point VL1 corresponds to point VL derived by the coordinate calculation unit 50a based on the output of left object detection device 51L at a point in the past. The same applies to points VL2 to VL4. Point VR11 corresponds to point VR derived by the coordinate calculation unit 50a based on the output of right object detection device 51R at a point in the future. The same applies to points VR12 to VR14. Furthermore, point VL11 corresponds to point VL that coordinate calculation section 50a derives based on the output of left object detection device 51L at a point in the future. The same applies to points VL11 to VL14.

[0065] The steering control unit 50b is configured to be able to automatically steer the asphalt finisher 100 regardless of the operation of an operating device such as a travel speed dial. Note that the steering control unit 50b may be configured to be able to control the travel speed of the asphalt finisher 100 when automatically steering the asphalt finisher 100. Also, the steering control unit 50b may be omitted.

[0066] The screed extension / retraction control unit 50c is configured to automatically extend and retract the left and right extendable rear screed 31 regardless of the operation of an operating device such as an extension / retraction button set. The screed extension / retraction control unit 50c may also be configured to automatically extend and retract the rear screed 31 in accordance with the traveling speed and steering angle of the asphalt finisher 100 when the asphalt finisher 100 is automatically steered.

[0067] In the illustrated example, the screed extension / retraction control unit 50c generates an extension / retraction command for the screed extension / retraction cylinder 7 based on the coordinates on the boundary line calculated and stored by the coordinate calculation unit 50a. The extension / retraction command may be, for example, a command regarding the extension / retraction speed, a command regarding the extension / retraction amount, or a combination thereof.

[0068] Specifically, the screed extension / retraction control unit 50c executes feedforward control of the extension / retraction amount of the rear screed 31. More specifically, the screed extension / retraction control unit 50c extends and retracts the left screed telescopic cylinder 7L so that the coordinates of a predetermined portion of the left rear screed 31L (e.g., the left front end point) coincide with the left target coordinates. The left target coordinates are an example of target coordinates, and are, for example, the coordinates of point VL located closest to and in front of the predetermined portion of the left rear screed 31L (e.g., the left front end point). The screed extension / retraction control unit 50c extends and retracts the right screed telescopic cylinder 7R so that the coordinates of a predetermined portion of the right rear screed 31R (e.g., the right front end point) coincide with the right target coordinates. The right target coordinates are another example of target coordinates, and are, for example, the coordinates of point VR located closest to and in front of the predetermined portion of the right rear screed 31R (e.g., the right front end point). The screed extension / contraction control unit 50c may also be configured to determine the extension / contraction speed in accordance with the travel speed of the asphalt finisher 100 detected by the travel speed sensor S1.

[0069] The coordinates of predetermined portions of the rear screed 31, such as the coordinates of the left front end point of the left rear screed 31L and the coordinates of the right front end point of the right rear screed 31R, can be calculated by the coordinate calculation unit 50a, similar to the coordinates of points VL and VR. Specifically, the coordinate calculation unit 50a can calculate the relative position of the object detection device 51 with respect to the position of a reference point, such as the center point of the tractor 1, based on the amount of extension and contraction of the extension member TA, which positions the object detection device 51. Similarly, the coordinate calculation unit 50a can calculate the relative positions of the left front end point of the left rear screed 31L and the right front end point of the right rear screed 31R with respect to the position of the reference point, based on the amount of extension and contraction of the rear screed 31. Furthermore, the coordinate calculation unit 50a can calculate the relative positions of the reference points at a second time point with respect to the positions of the reference points at a first time point, based on the outputs of the travel speed sensor S1, the steering angle sensor, etc. Therefore, the coordinate calculation unit 50a can calculate the relative positions of point VL, point VR, the left front end point of the left rear screed 31L, and the right front end point of the right rear screed 31R at other times relative to the position of the reference point at a first time point.

[0070] Next, a process (hereinafter referred to as "target setting process") in which the controller 50 sets a target when extending or retracting the rear screed 31 will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the flow of the target setting process. The controller 50 repeatedly executes this target setting process at a predetermined control cycle.

[0071] First, the controller 50 acquires the vehicle body coordinates (step ST1). The vehicle body coordinates refer to the coordinates of predetermined parts of the asphalt finisher 100, and include the coordinates of predetermined parts of the rear screed 31, such as the coordinates of the left front end point of the left rear screed 31L and the coordinates of the right front end point of the right rear screed 31R.

[0072] Specifically, the controller 50 stores the center point of the asphalt finisher 100 at a first point in time, such as the start of construction, as a reference point.

[0073] During construction, the controller 50 can derive the relative position of the center point of the asphalt finisher 100 and the orientation of the asphalt finisher 100 at any point in time, such as the current time, based on the outputs of the traveling speed sensor S1 and the steering angle sensor. Note that the relative position of the center point means the relative position of the center point with respect to a reference point. The same applies to the following explanation.

[0074] In the illustrated example, the controller 50 can derive the coordinates of the turning center based on the output of the steering angle sensor. The controller 50 can then derive the relative position of the center point of the asphalt finisher 100 and the orientation of the asphalt finisher 100 at any time, such as the current time, based on the coordinates of the turning center and the output of the traveling speed sensor S1. The controller 50 may also be configured to derive the travel distance or change in attitude based on the output of an IMU (Inertial Measurement Unit), GNSS (Global Navigation Satellite System), or surveying equipment (not shown) mounted on the asphalt finisher 100. Furthermore, the controller 50 can derive the relative position of a predetermined portion of the asphalt finisher 100 at any time based on the relative position of the center point of the asphalt finisher 100 and the orientation of the asphalt finisher 100 at any time and the known dimensions of each component constituting the asphalt finisher 100. The relative positions of the predetermined portions of the asphalt finisher 100 include the relative position of the left object detection device 51L and the relative position of the right object detection device 51R.

[0075] After acquiring the vehicle body coordinates, the controller 50 acquires feature coordinates (step ST2). The feature coordinates refer to the coordinates of features such as the object AP, and include the coordinates on the left boundary line of the road to be constructed, the coordinates on the right boundary line of the road to be constructed, and the like.

[0076] Specifically, the controller 50 can calculate the coordinates of point VL, which is the coordinate on the left boundary line of the road to be worked on, and the coordinates of point VR0, which is the coordinate on the right boundary line of the road to be worked on, based on the relative position of the center point of the asphalt finisher 100 and the orientation of the asphalt finisher 100 at any time and the output of the object detection device 51 at any time.

[0077] After acquiring the vehicle body coordinates and the feature coordinates, the controller 50 sets a target (step ST3). In the illustrated example, the controller 50 calculates a target value for the expansion / contraction amount of the rear screed 31.

[0078] Specifically, the controller 50 derives the distance (hereinafter referred to as the "first distance") between the point VL located closest to and in front of a predetermined portion of the left rear screed 31L (e.g., the left front end point) and the longitudinal axis AX serving as the central axis of the asphalt finisher 100, based on the relative position of the center point of the asphalt finisher 100 at the current time and the orientation of the asphalt finisher 100. The controller 50 also derives the distance (hereinafter referred to as the "second distance") between a predetermined portion of the left rear screed 31L (e.g., the left front end point) and the longitudinal axis AX of the asphalt finisher 100, based on the relative position of the center point of the asphalt finisher 100 at the current time and the orientation of the asphalt finisher 100. The controller 50 then sets the difference between the first distance and the second distance as the target extension amount. Specifically, if the first distance is greater than the second distance, the controller 50 sets the difference between the first distance and the second distance as the target expansion amount, and if the first distance is smaller than the second distance, the controller 50 sets the difference between the first distance and the second distance as the target contraction amount.

[0079] The controller 50 also determines the extension / contraction speed based on the distance in the travel direction between a predetermined portion of the left rear screed 31L (for example, the left front end point) and the point VL located closest to the position in front of it (hereinafter referred to as the "third distance"). Specifically, if the target extension / contraction amount is the same, the controller 50 sets the extension / contraction speed to be higher as the third distance is larger.

[0080] Alternatively, the controller 50 may predict the position of a predetermined portion (e.g., the left front end point) of the left rear screed 31L after a predetermined time (e.g., one second), and derive a line segment connecting the closest point VL in front of the position of the predetermined portion after the predetermined time and the closest point VL behind it. The controller 50 may then determine the distance between an interpolation point (a point that interpolates two points VL) on that line segment and the longitudinal axis AX as the first distance.

[0081] With this configuration, the controller 50 can grasp the position of the boundary line ahead of the screed 3, and can extend and retract the rear screed 31 just right at the appropriate timing. Therefore, the controller 50 can suppress or prevent delays in extension and retraction of the rear screed 31 when the construction width changes, thereby improving construction accuracy.

[0082] With the above-described configuration, the screed extension / contraction control unit 50c can extend or contract the left rear screed 31L so that the coordinates of the left front end point of the left rear screed 31L coincide with the coordinates on the guide line GD when the asphalt finisher 100 has advanced a predetermined distance. In other words, the screed extension / contraction control unit 50c can control the amount of extension / contraction of the left rear screed 31L so that when the distance in the traveling direction between point VL and the left front end point of the left rear screed 31L at any point in time becomes zero, the distance in the vehicle width direction between point VL and the left front end point of the left rear screed 31L also becomes zero.

[0083] Similarly, the screed extension / contraction control unit 50c can extend or contract the right rear screed 31R so that the coordinates of the right front end point of the right rear screed 31R match the coordinates of the nearest point VR located ahead of it when the asphalt finisher 100 has advanced a predetermined distance. In other words, the screed extension / contraction control unit 50c can control the amount of extension / contraction of the right rear screed 31R so that when the distance in the traveling direction between point VR and the right front end point of the right rear screed 31R at any point in time becomes zero, the distance in the vehicle width direction between point VR and the right front end point of the right rear screed 31R also becomes zero.

[0084] As described above, an asphalt finisher 100, which is an example of a road machine according to an embodiment of the present disclosure, comprises, as shown in Figures 1 and 2, a tractor 1, a hopper 2 installed in front of the tractor 1 to receive paving material PV, a conveyor CV that feeds the paving material PV in the hopper 2 to the rear of the tractor 1, a screw SC that spreads the paving material PV fed by the conveyor CV behind the tractor 1, a screed 3 that spreads the paving material PV spread by the screw SC behind the screw SC, and a control device (controller 50) that calculates the coordinates of the boundary line (guide line GD) in a predetermined coordinate system based on information about a feature (object AP) that defines the boundary line (guide line GD) of the construction area located ahead of the screed 3.

[0085] Furthermore, in the asphalt finisher 100, the screed 3 is configured to be extendable and retractable in the vehicle width direction. Therefore, the controller 50 can extend and retract the screed 3 so that the coordinates on the boundary line (guide line GD) and the coordinates of the end of the screed 3 coincide with each other.

[0086] With this configuration, the controller 50 can recognize a change in the direction of the boundary line (guide line GD) before the screed 3 reaches the part where the direction of the boundary line (guide line GD) changes. Therefore, the controller 50 can appropriately control the amount of extension and contraction of the screed 3 compared to when the controller 50 recognizes that a gap exists between the end of the screed 3 and the boundary line (guide line GD) and then extends or contracts the screed to reduce the gap. In other words, the controller 50 can prevent a gap from occurring between the end of the screed 3 and the boundary line (guide line GD).

[0087] Furthermore, in the asphalt finisher 100, the controller 50 may be configured to calculate coordinates on the boundary line (guide line GD) each time the tractor 1 moves forward a predetermined distance. In the example shown in Fig. 2, the controller 50 is configured to continuously calculate and store the coordinates of points VL and VR on the boundary line (guide line GD).

[0088] This configuration has the effect of preventing the computation load for calculating coordinates from becoming greater than necessary.

[0089] In other words, the controller 50 is configured to extend or retract the screed 3 so that the coordinates on the boundary line (guide line GD) calculated at a first point in time become the target coordinates of the end of the screed 3 at a second point in time that is later than the first point in time.

[0090] This configuration allows the controller 50 to recognize a change in the direction of the boundary line (guide line GD) before the screed 3 reaches the part where the direction of the boundary line (guide line GD) changes. Therefore, this configuration has the effect of more appropriately controlling the extension and contraction amount of the screed 3.

[0091] The asphalt finisher 100 may also include an object detection device 51 that acquires information about a feature (object AP) that defines a boundary line (guide line GD) of the road to be worked on and is located ahead of the screed 3. The object detection device 51 may also be arranged ahead of the screed 3. In the example shown in FIG. 2, the object detection device 51 is arranged ahead of the tractor 1, which is located in front of the screed 3.

[0092] With this configuration, the object detection device 51 can obtain information about the portion where the orientation of the boundary line (guide line GD) changes (for example, the relative position with respect to the vehicle body (tractor 1), a distance image, or an image, etc.) before the screed 3 reaches the portion. Therefore, this configuration has the effect of enabling the controller 50 to recognize the change in the orientation of the boundary line (guide line GD) before the screed 3 reaches the portion where the orientation of the boundary line (guide line GD) changes.

[0093] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. Various modifications or substitutions may be applied to the above-described embodiments without departing from the scope of the present invention. Furthermore, the features described with reference to the above-described embodiments may be combined as appropriate unless technically inconsistent.

[0094] For example, in the above-described embodiment, the object detection device 51 is configured to acquire information about the feature (object AP) that defines the boundary line (guide line GD) of the construction area located ahead of the screed 3. However, the controller 50 may be configured to acquire information about the feature (object AP) from design data or the like that is pre-stored in a volatile storage device or a non-volatile storage device. In this case, acquisition of information about the feature (object AP) by the object detection device 51 may be omitted.

[0095] Furthermore, in the above-described embodiment, the object detection device 51 is attached to the asphalt finisher 100, but it may also be attached to a moving body other than the asphalt finisher 100, such as a vehicle or a multicopter. [Explanation of symbols]

[0096] 1 Tractor 1S Driver's seat 2 Hopper 3 Screed 3A Leveling arm 3AL Left leveling arm 3AR Right leveling arm 5 Rear wheel 6 Front wheel 7 Screed telescopic cylinder 7L Left screed telescopic cylinder 7R Right screed telescopic cylinder 30 Front screed 30L Left front screed 30R Right front screed 31 Rear screed 31L Left rear screed 31R Right rear screed 32 Step 32C Center step 32L Left step 32R Right step 41 Side plate 41L Left side plate 41R Right side plate 42 Moldboard 42L Left moldboard 42R Right moldboard 43 Retaining plate 43L Left retaining plate 43R Right retaining plate 50 Controller 50a Coordinate calculation unit 50b Steering control unit 50c Screed extension / retraction control unit 51 Object detection device 51L Left object detection device 51R Right object detection device 52 On-board display device 53 Steering device 54 Screed extension / retraction device 60 Mounting member 60L Left mounting member 60R Right mounting member 100 Asphalt finisher AP Object APL Left object APL1 First left object APL2 Second left object APR Right object APR1...First right object APR2...Second right object AX...Front and rear axle BS...Road base CL...Center line CV...Conveyor DS...Operation support system GD...Guide line GDL...Left guide line GDR...Right guide line NP...New pavement PV...Pavement material S1...Traveling speed sensor SB, SBa...Pivoting member SC...Screw SC...Screw SCL...Left extension screw SCR...Right extension screw SH...Steering wheel TA...Telescopic member ZL...Left monitoring area ZR...Right monitoring area

Claims

1. A tractor and a hopper installed in front of the tractor to receive paving material; a conveyor that feeds the paving material in the hopper to the rear of the tractor; a screw that spreads the paving material fed by the conveyor behind the tractor; a screed that spreads the paving material spread by the screw behind the screw; an object detection device for acquiring information about features that define the boundary of a construction area located forward of the screed; a control device that calculates coordinates on the boundary line in a predetermined coordinate system based on information acquired by the object detection device, The object detection device is attached to a part of the road machine other than the screed, or to a moving body other than the road machine, and is arranged forward of the screed, and includes at least one of a left object detection device that monitors the ground on the left side of the road machine and a right object detection device that monitors the ground on the right side of the road machine, The range monitored by the object detection device is a range including the boundary line of the construction target range located forward of the screed, The left and right width of the range monitored by the object detection device is smaller than the left and right width of the construction target range. Road machinery.

2. The screed is extendable and retractable in the vehicle width direction, The control device extends and retracts the screed so that the coordinates on the boundary line and the coordinates of the end of the screed coincide with each other.

2. A road machine according to claim 1.

3. the control device calculates coordinates on the boundary line each time the tractor moves forward a predetermined distance.

3. A road machine according to claim 1 or 2.

4. The control device extends and retracts the screed so that the coordinates on the boundary line calculated at a first point in time become target coordinates of the end of the screed at a second point in time after the first point in time, 3. A road machine according to claim 1 or 2.

5. the object detection device is attached to the road machine via an attachment member, The attachment member includes an elastic member that is elastic in the width direction and a rotating member that is rotatably connected to a distal end of the elastic member.

3. A road machine according to claim 1 or 2.

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