Asphalt rolling machine

Abstract

The invention provides an asphalt roll-leveling machine which can perform automatic operation on a traction machine more appropriately. An asphalt rolling machine (100) is provided with: a tractor (1); the hopper (2) is arranged on the front side of the tractor (1) and is used for receiving paving materials; a conveyor (CV) for supplying the paving material in the hopper (2) to the rear side of the tractor (1); a screw (SC) that spreads the paving material supplied by the conveyor (CV) on the rear side of the tractor (1); a leveling machine (3) for uniformly spreading the paving material spread by the screw (SC) on the rear side of the screw (SC); an object detection device (51) that acquires information relating to an object (AP) provided on the ground of the construction object; and a controller (50) that generates a guide line on the basis of a change in the object (AP), and manipulates the tractor (1) on the basis of the guide line and a reference line indicating the vehicle length direction of the tractor (1).

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2022-064595 filed on April 8, 2022. The entire contents of the Japanese Patent Application are incorporated herein by reference.

[0002] The invention relates to an asphalt roller. Background Art

[0003] In the past, there is known an asphalt roller, which includes: a tractor; a hopper, which is arranged on the front side of the tractor and receives paving materials; a conveyor, which supplies the paving materials in the hopper to the rear side of the tractor; a screw, which spreads the paving materials supplied by the conveyor on the rear side of the tractor; and a leveler, which evenly spreads the paving materials spread by the screw on the rear side of the screw.

[0004] Also, there is known an asphalt roller that automatically operates a tractor so that the end surface of the pavement to be laid in the width direction extends along a travel reference line drawn on the ground surface of the construction object (see Patent Documents 1 and 2).

[0005] The asphalt rollers disclosed in Patent Documents 1 and 2 include a rod-shaped member mounted on a hopper so as to protrude in the vehicle width direction and a plurality of light sensors mounted on the front end of the rod-shaped member and outputting light toward the ground. The plurality of light sensors are arranged in a row in the vehicle width direction and are capable of detecting a travel reference line by receiving light reflected from the travel reference line.

[0006] According to this structure, the asphalt roller disclosed in Patent Document 1 and Patent Document 2 can detect whether the tractor is traveling along the travel reference line, approaching the travel reference line, or moving away from the travel reference line. Furthermore, when the asphalt roller detects that the tractor is approaching the travel reference line, the tractor is operated to move away from the travel reference line, and when the tractor is detected to move away from the travel reference line, the tractor is operated to move closer to the travel reference line.

[0007] Patent Document 1: Japanese Patent Publication No. 3-40163

[0008] Patent Document 2: Japanese Patent Publication No. 4-32883

[0009] However, the asphalt rollers disclosed in Patent Documents 1 and 2 can operate the tractor only after detecting that the tractor approaches or moves away from the travel reference line. Summary of the invention

[0010] In view of the above circumstances, it is desirable to provide an asphalt roller capable of automatically operating a tractor more appropriately.

[0011] The asphalt roller involved in the embodiment of the present invention includes: a tractor; a hopper, which is provided at the front side of the tractor and receives paving materials; a conveyor, which supplies the paving materials in the hopper to the rear side of the tractor; a screw, which spreads the paving materials supplied by the conveyor at the rear side of the tractor; a leveler, which evenly spreads the paving materials spread by the screw at the rear side of the screw; an object detection device, which acquires information related to ground objects existing within a specified range on the ground of a construction object; and a control device, which generates a guide line according to changes in the ground object, and controls the tractor according to the guide line and a reference line indicating the vehicle length direction of the tractor.

[0012] Effects of the Invention

[0013] By means of the above, an asphalt roller capable of automatically manipulating the tractor more appropriately is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a side view of the asphalt roller according to the embodiment of the present invention.

[0015] Figure 2 yes Figure 1 Top view of an asphalt roller.

[0016] Figure 3 It is a diagram showing a configuration example of an automatic control system.

[0017] Figure 4 This is a schematic three-dimensional diagram of a paving formwork.

[0018] Figure 5 A diagram showing an example of a distance image generated based on the output of the object detection device.

[0019] Figure 6 A diagram showing an example of a distance image generated based on the output of the object detection device.

[0020] Figure 7 This is a diagram showing another example of a distance image generated based on the output of the object detection device.

[0021] Figure 8 A top view of an asphalt roller being automatically operated.

[0022] Fig. 9 This is a top view of the paving site.

[0023] In the figure: 1-tractor, 1S-driver's seat, 2-hopper, 3-leveler, 3A-leveling arm, 3AL-left leveling arm, 3AR-right leveling arm, 5-rear wheel, 6-front wheel, 30-front leveler, 30L-left front leveler, 30R-right front leveler, 31-rear leveler, 31L-left rear leveler, 31R-right rear leveler, 43-moldboard, 50-controller, 50a-guide line generating unit, 50b-operating control unit, 50c-leveler telescopic control unit, 51-object detection device, 51L-left object detection device, 51R-right object detection device, 52-vehicle display device, 53-operating device, 60-installation component, 60L-left installation component, 60R-right installation component, 100-asphalt roller Machine, AP-object, APL-left object, APR-right object, APR1, APR2-paving frame, BS-roadbed, CL-center line, CV-conveyor, DM, DMa, DMb, DM0~DM3-distance image, DS-automatic control system, GD-guide line, GDL-left guide line, GDR-right guide line, L1, L2-center line, NP-new pavement, PV-paving material, S1-travel speed sensor, SB, SBa-rotating part, SC-screw, SH-steering wheel, TA-telescopic part, TR-track, WD-widening part, WD1-first widening part, WD2-second widening part, WD3-third widening part, ZL-left monitoring range, ZR, ZR1, ZR3-right monitoring range. DETAILED DESCRIPTION

[0024] Figure 1 It is a side view of the asphalt roller 100 according to the embodiment of the present invention. Figure 2 1 is a top view of the asphalt roller 100. In the present embodiment, the asphalt roller 100 is a wheeled asphalt roller, and is mainly composed of a tractor 1, a hopper 2, and a screed machine 3. Hereinafter, the direction of the hopper 2 observed from the tractor 1 (+X direction) is set as the front, and the direction of the screed machine 3 observed from the tractor 1 (-X direction) is set as the rear.

[0025] The tractor 1 is a mechanism for moving the asphalt roller 100. In the present embodiment, the tractor 1 rotates the rear wheels 5 using a rear wheel travel hydraulic motor and rotates the front wheels 6 using a front wheel travel hydraulic motor to move the asphalt roller 100. The rear wheel travel hydraulic motor and the front wheel travel hydraulic motor receive the supply of hydraulic oil from a hydraulic pump to rotate. However, the front wheel 6 may be a driven wheel.

[0026] Asphalt roller 100 can be a crawler type asphalt roller. At this moment, the combination of rear wheel 5 and front wheel 6 can be replaced with the combination of left crawler and right crawler.

[0027] The hopper 2 is a mechanism for receiving paving materials. In the present embodiment, the hopper 2 is provided at the front side of the tractor 1, and is configured to be openable and closable in the vehicle width direction (Y-axis direction) by a hopper cylinder. Generally, the asphalt roller 100 receives paving materials (e.g., asphalt mixture) from the cargo box of a dump truck when the hopper 2 is in a fully open state. The dump truck is an example of a transport vehicle for transporting paving materials. Figure 1 and Figure 2 Indicates that the hopper 2 is in a fully open state. If the paving material in the hopper 2 decreases, the hopper 2 is closed, and the paving material present near the inner wall of the hopper 2 is concentrated in the center of the hopper 2. This is to enable the conveyor CV present in the center of the hopper 2 to supply paving materials to the rear side of the tractor 1. The paving material supplied to the rear side of the tractor 1 by the conveyor CV is spread in the vehicle width direction at the rear side of the tractor 1 and in front of the leveler 3 by the screw SC. In this embodiment, the screw SC is in a state where the extension screw is connected to the left and right. Figure 1 and Figure 2 In the figure, for the sake of clarity, the paving material in the hopper 2 is omitted, the paving material PV spread by the screw SC is represented by a thick dot pattern, and the newly installed pavement NP evenly spread by the leveling machine 3 is represented by a thin dot pattern.

[0028] The screed 3 is a mechanism for evenly spreading the paving material PV. In the present embodiment, 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 can be extended and retracted in the vehicle width direction, and includes a left rear screed 31L and a right rear screed 31R. However, the rear screed 31 may be a fixed width screed connected to the left and right of the front screed 30. In the case of a fixed width screed, the left rear screed 31L and the right rear screed 31R may be installed at the same position in the front-to-back direction. Furthermore, 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. In addition, an end leveling device may be disposed at the end of the rear leveling machine 31 .

[0029] A moldboard 43 is attached to the front of the screed machine 3. The moldboard 43 is configured to be able to adjust the amount of the paving material PV accumulated in front of the screed machine 3. The paving material PV reaches below the screed machine 3 through a gap between the lower end of the moldboard 43 and the roadbed BS.

[0030] The tractor 1 is equipped with a travel speed sensor S1 , a controller 50 , an object detection device 51 , an on-board display device 52 , and an operating device 53 .

[0031] The travel speed sensor S1 is configured to detect the travel speed of the asphalt roller 100. In the present embodiment, the travel speed sensor S1 is a wheel speed sensor, and is configured to detect the rotational angular velocity and rotation angle of the rear wheel 5 and the travel speed and travel distance of the asphalt roller 100.

[0032] The controller 50 is a control device for controlling the asphalt roller 100. In the present embodiment, the controller 50 is composed of a microcomputer including a CPU, a volatile storage device, a non-volatile storage device, etc. The CPU executes the program stored in the non-volatile storage device, thereby realizing various functions of the controller 50. However, various functions of the controller 50 can be realized not only by software, but also by hardware, or by a combination of hardware and software.

[0033] The object detection device 51 is configured to obtain information related to ground objects existing within a specified range of the ground of the construction object, and output the obtained information to the controller 50. That is, the object detection device 51 is configured to set the specified range of the ground of the construction object as the monitoring object. The specified range on the ground is a range having a front-to-back width and a left-to-right width greater than the width of the paving formwork, for example, a 2-meter square range.

[0034] The ground features existing within the predetermined range include, for example, the roadbed BS and the object AP existing outside the roadbed BS. Specifically, the object AP is a ground feature used to determine the position of the end surface of the laid pavement in the width direction. Figure 1 and Figure 2 In the example shown, the object AP is a paving formwork having a specified thickness (height), including a left object APL existing on the left side of the asphalt roller 100 and a right object APR existing on the right side of the asphalt roller 100. The object AP may be an L-shaped side channel block, a curbstone, or a cut step portion of an existing paving body. The cut step portion of an existing paving body refers to a step portion between the surface of the cut portion and the surface of the uncut portion formed when the old paving body is cut and a new paving body is laid. The object AP may be a ground object with almost no thickness, such as a line drawn on the ground, a tape attached to the ground, or a rope extending along the ground. Information related to the ground object includes, for example, the height of the ground object, the color of the surface of the ground object, or the reflectivity of the surface of the ground object. In addition, in Figure 1 In the figure, the illustration of the left object APL is omitted for clarity.

[0035] In this embodiment, the object detection device 51 is a stereo camera configured to monitor a specified range. In addition, the object detection device 51 can be a monocular camera, LIDAR, millimeter wave radar, laser radar, laser scanner, distance image camera, laser rangefinder or ultrasonic sensor configured to monitor a specified range.

[0036] Furthermore, the stereo camera as the object detection device 51 is preferably configured to have an automatic exposure adjustment function. With this configuration, the object detection device 51 can acquire information on floor features existing within a predetermined range regardless of day or night, that is, without requiring special lighting or the like.

[0037] In the present embodiment, the object detection device 51 includes a left object detection device 51L provided on the left side of the asphalt roller 100 and a right object detection device 51R provided on the right side of the asphalt roller 100 .

[0038] The left object detection device 51L is configured to monitor the ground on the left side of the asphalt roller 100. In the present embodiment, the left object detection device 51L is configured to monitor the left monitoring range ZL ( Figure 2 A stereo camera in the range surrounded by a single dotted line.

[0039] The right object detection device 51R is configured to monitor the ground on the right side of the asphalt roller 100. In the present embodiment, the right object detection device 51R is configured to monitor the right monitoring range ZR ( Figure 2 A stereo camera in the range surrounded by a single dotted line.

[0040] The object detection device 51 can be mounted on the asphalt roller 100 via the mounting member 60. The mounting member 60 is a member used to mount the object detection device 51 on the asphalt roller 100. In this embodiment, the mounting member 60 includes a left mounting member 60L and a right mounting member 60R. Figure 2 In the example shown, the left object detection device 51L is mounted on the left front end of the tractor 1 via the left mounting member 60L, and the right object detection device 51R is mounted on the right front end of the tractor 1 via the right mounting member 60R. In addition, the left object detection device 51L can be mounted on other parts of the asphalt roller 100 such as the left front end of the hopper 2 via the left mounting member 60L. Similarly, the right object detection device 51R can be mounted on other parts of the asphalt roller 100 such as the right front end of the hopper 2 via the right mounting member 60R.

[0041] Furthermore, the object detection device 51 may be configured to monitor the telescopic state of the rear leveler 31. For example, the object detection device 51 may additionally include a stereo camera configured to monitor the end of the left rear leveler 31L and a stereo camera configured to monitor the end of the right rear leveler 31R. In this case, the object detection device 51 may be configured on the leveler 3. For example, the object detection device 51 may be configured on the rear leveler 31. Furthermore, when an end leveler is configured on the end of the rear leveler 31, the object detection device 51 may be configured on the end leveler.

[0042] And, in Figure 2 In the illustrated example, the object detection device 51 is mounted on the mounting member 60 so as to face vertically downward, but may be mounted on the mounting member 60 so as to face other directions such as obliquely downward.

[0043] And, in Figure 2 In the example shown, the left mounting member 60L is composed of a telescopic member TA that can be telescoped in the width direction and a rotating member SB that is rotatably connected to the distal end of the telescopic member TA. Figure 2 The rotating member SBa indicated by the dotted line in the figure shows the state when the rotating member SB is rotating. The same is true for the right mounting member 60R.

[0044] In this way, the mounting member 60 is configured to be movable within the monitoring range of the object detection device 51 through the telescopic member TA and the rotating member SB. This is to enable the object detection device 51 to follow the object AP even if the configuration position of the object AP changes to the left or right in the traveling direction. The controller 50 can keep the object AP within the monitoring range of the object detection device 51.

[0045] The attachment member 60 may include at least one of a sensor for detecting the expansion and contraction amount of the telescopic member TA and a sensor for detecting the rotation amount (rotation angle) of the rotating member SB.

[0046] In addition, 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.

[0047] Furthermore, the object detection device 51 may be directly mounted on the asphalt finisher 100 without using the mounting member 60 .

[0048] Furthermore, the asphalt roller 100 may be equipped with a steering angle sensor configured to detect the steering angle of the asphalt roller 100 and a screed expansion and contraction amount sensor configured to detect the expansion and contraction amount of the rear screed 31 .

[0049] The vehicle-mounted display device 52 is configured to display information related to the asphalt roller 100. In the present embodiment, the vehicle-mounted display device 52 is a liquid crystal display provided in front of the driver's seat 1S. However, the vehicle-mounted display device 52 may include a display device provided at at least one of the left end and the right end of the leveler 3.

[0050] The operating device 53 is configured to be able to operate the asphalt roller 100. In the present embodiment, the operating device 53 is configured to extend and retract the front wheel control cylinder provided near the front axle. Specifically, the operating device 53 includes an operating electromagnetic control valve that controls the flow rate of the working oil flowing from the hydraulic pump to the front wheel control cylinder and the flow rate of the working oil discharged from the front wheel control cylinder. The operating electromagnetic control valve is configured to be able to control the outflow / inflow of the working oil in the front wheel control cylinder according to the rotation of the steering wheel SH (steering wheel) as an operating device. Furthermore, the operating electromagnetic control valve is configured to be able to control the outflow / inflow of the working oil in the front wheel control cylinder according to the operating instruction from the controller 50, regardless of the rotation of the steering wheel SH. That is, the controller 50 can automatically operate the asphalt roller 100 regardless of whether the driver operates the steering wheel SH.

[0051] When the asphalt roller 100 is a crawler type asphalt roller, the control device 53 is configured to independently control a pair of left and right crawlers. In addition, the crawler type asphalt roller has a left operating lever for operating the left crawler and a right operating lever for operating the right crawler instead of the steering wheel SH.

[0052] Specifically, the operating device 53 includes a left electromagnetic control valve for controlling the flow of working oil from the hydraulic pump to the left travel hydraulic motor for rotating the left track, and a right electromagnetic control valve for controlling the flow of working oil from the hydraulic pump to the right travel hydraulic motor for rotating the right track. In addition, the left electromagnetic control valve is configured to control the outflow / inflow of working oil in the left travel hydraulic motor according to the operation amount (tilt angle) of the left operating lever. In addition, the left electromagnetic control valve is configured to control the outflow / inflow of working oil in the left travel hydraulic motor according to the operation instruction from the controller 50, regardless of whether the driver operates the left operating lever. Similarly, the right electromagnetic control valve is configured to control the outflow / inflow of working oil in the right travel hydraulic motor according to the operation amount (tilt angle) of the right operating lever. In addition, the right electromagnetic control valve is configured to control the outflow / inflow of working oil in the right travel hydraulic motor according to the operation instruction from the controller 50, regardless of whether the driver operates the right operating lever.

[0053] Next, refer to Figure 3 A configuration example of the automatic control system DS mounted on the asphalt roller 100 will be described. Figure 3It is a block diagram showing a configuration example of the automatic control system DS.

[0054] The automatic steering system DS is mainly composed of a controller 50 , a left object detection device 51L, a right object detection device 51R, a travel speed sensor S1 , an on-vehicle display device 52 , and a steering device 53 .

[0055] exist Figure 3 In the illustrated example, the controller 50 includes a guide line generating section 50 a , a steering control section 50 b , and a leveler extension and retraction control section 50 c as functional modules.

[0056] The guide line generation unit 50a is configured to generate a guide line GD based on information related to the ground object acquired by the object detection device 51. The guide line GD is an example of a target line and is an imaginary line representing a guide surface. The guide surface is an imaginary surface that is identified as a surface that should align the end surfaces of the paved body in the width direction. Figure 2 In the example shown, the guide lines GD include a left guide line GDL indicating a left guide surface with which the left end surface of the new pavement NP should be aligned, and a right guide line GDR indicating a right guide surface with which the right end surface of the new pavement NP should be aligned.

[0057] The guide line generation unit 50a generates a left guide line GDL based on information about the left object APL acquired by the left object detection device 51L, and generates a right guide line GDR based on information about the right object APR acquired by the right object detection device 51R.

[0058] For example, Figure 4 As shown, the guide line generation unit 50a generates the right guide line GDR so that the imaginary line representing the edge between the left end surface LE and the upper end surface UE of the right object APR existing in the right monitoring range ZR becomes the right guide line GDR. Figure 4 It is a schematic perspective view of a paving template as the right object APR as viewed from the rear of the asphalt roller 100 , and schematically shows the positional relationship between the right object detection device 51R and the right object APR.

[0059] For example, the guide line generator 50a generates the right guide line GDR using a distance image related to the right monitoring range ZR generated based on the output of the stereo camera as the right object detector 51R. The distance image is a data set that represents the pixel value of each pixel group arranged two-dimensionally as the distance from the right object detector 51R.

[0060] The guide line generator 50a extracts pixels whose difference with the left neighbor pixel value is equal to or greater than a predetermined threshold value from the pixels constituting the distance image, and derives a straight line based on the arrangement of the extracted pixels. The method of deriving a straight line can use any image recognition technology such as Hough transform.

[0061] The guide line generation unit 50a can eliminate these effects by averaging the extracted pixel positions where the positions are different. Specifically, such differences may occur in the image portion corresponding to the portion where two paving frames meet or the irregularity of the cut step portion.

[0062] In this example, the predetermined threshold is a threshold TH related to the height of the paving formwork. Figure 4 As shown, the guide line generation unit 50a can generate, as the right guide line GDR, a virtual line indicating the upper left edge of the pavement formwork, ie, the right object APR, which has a height H1 greater than or equal to the threshold value TH.

[0063] In addition, the threshold value TH can be configured to be set in advance according to the height of the paving frame actually used. The use of the threshold value TH set according to the height of the paving frame actually used enables the generation of a guide line based on the edge of the thin layer frame. Furthermore, the use of the threshold value TH set according to the height of the paving frame actually used can prevent the guide line generation unit 50a from erroneously generating a guide line based on the shape (edge) of a ground feature other than the paving frame.

[0064] The above description relates to the process of generating the right guide line GDR based on the distance image related to the right monitoring range ZR, but is also applicable to the process of generating the left guide line GDL based on the distance image related to the left monitoring range ZL.

[0065] Furthermore, when the object detection device 51 is a monocular camera, the “distance image” in the above description is replaced by “image.” In this case, the “pixel value” is represented by color information, etc., rather than by distance. The color information may be brightness.

[0066] The steering control unit 50b is configured to automatically control the asphalt roller 100 regardless of the operation of the operating device. In addition, the steering control unit 50b may be configured to control the travel speed of the asphalt roller 100 when the asphalt roller 100 is automatically controlled.

[0067] The screed extension control unit 50c is configured to automatically extend and retract the rear screed 31 which can be extended and retracted left and right independently of the operation of the operating device. In addition, the screed extension control unit 50c can be configured to automatically control the asphalt roller 100 according to the travel speed of the asphalt roller 100 when the asphalt roller 100 is automatically operated.

[0068] In the present embodiment, the steering control unit 50b generates a steering instruction to the steering device 53 based on the guide line GD and the baseline BL generated by the guide line generating unit 50a. The steering instruction includes, for example, information related to the steering direction and information related to the steering amount. The information related to the steering direction is, for example, information related to whether to steer to the right or to the left. The information related to the steering amount is, for example, information related to the steering angle, typically information related to the change or size of the steering angle (target steering angle) from the start of automatic steering to the stop of automatic steering. The steering control unit 50b can determine the information related to the steering angle based on the size of the travel speed of the asphalt roller 100 detected by the travel speed sensor S1. In addition, the steering instruction may include, for example, information related to the steering angle velocity (the rate of increase or decrease of the steering angle per unit time).

[0069] The reference line BL is an imaginary straight line used when generating a steering command. In the present embodiment, the reference line BL is a line indicating the vehicle length direction (length direction) of the tractor 1. This means that the reference line BL is set in a direction perpendicular to the axis (axle) of the front wheel 6. In this example, the steering control unit 50b is configured to generate a steering command by comparing the guide line GD with the reference line BL.

[0070] Specifically, the steering control unit 50b identifies the deviation between the guide line GD and the reference line BL, and generates a steering instruction according to the magnitude of the identified deviation. Figure 5 As shown, the steering control unit 50b calculates the distance between the reference line BL and the guide line GD in the vehicle width direction as the deviation amount DF. Furthermore, the steering control unit 50b calculates the angle formed between the reference line BL and the guide line GD as the deviation angle θ. Furthermore, the steering control unit 50b generates a steering command that can make the deviation amount DF and the deviation angle θ close to zero, that is, a steering command that can make the reference line BL and the guide line GD coincide with each other.

[0071] in addition, Figure 5 An example of a distance image DM generated based on the output of a stereo camera serving as the right object detection device 51R is shown. Figure 5 The finer the dot pattern, the closer the distance. Figure 5 (A) shows an example of the distance image DMa acquired when a deviation occurs between the vehicle length direction of the asphalt roller 100 and the extending direction of the paving template as the right object APR. Figure 5 (B) shows an example of the distance image DMb acquired when the vehicle length direction of the asphalt roller 100 coincides with the extending direction of the paving template as the right object APR.

[0072] The manipulation control unit 50b is configured, for example, to obtain Figure 5 When the distance image DMa shown in (A) is obtained, an appropriate control instruction is generated, and the tractor 1 is automatically controlled to obtain Figure 5 The distance image DMa as shown in (B).

[0073] And, for example, when obtaining Figure 5 When the distance image DMa shown in (A) is obtained, the leveler extension and retraction control unit 50c generates an appropriate extension and retraction command for any one of the rear levelers 31 that can be extended and retracted to the left and right.

[0074] In addition, Figure 5 In FIG. 5 , the longitudinally extending center line indicated by the dotted line in the distance image DM corresponds to the reference line BL indicating the vehicle length direction of the asphalt roller 100 (tractor 1). Figure 5 In the distance image DM, the laterally extending center line indicated by the dotted line corresponds to the orthogonal line TL indicating the vehicle width direction of the asphalt roller 100 (tractor 1). Furthermore, the center point CP of the distance image DM, which is the intersection point of the reference line BL and the orthogonal line TL, corresponds to a point on the ground (surface of the roadbed BS) located directly below the center of the right object detection device 51R.

[0075] exist Figure 5 In the example shown in (A), the deviation DF between the baseline BL and the right guide line GDR is represented by the distance between the intersection of the orthogonal line TL and the right guide line GDR, that is, the point P1 and the center point CP, and becomes the value DFa. In addition, the deviation angle θ formed between the baseline BL and the right guide line GDR is the value θa. Figure 5 In (B), the deviation amount DF and the deviation angle θ are both zero.

[0076] In this example, when point P1 is located outside (on the right side) of the center point CP, the deviation DF becomes a positive value, and when point P1 is located inside (on the left side) of the center point CP, the deviation DF becomes a negative value. Figure 5 Regarding the reference line BL shown in (A), when the guide line GD is inclined outward (rightward), the deviation angle θ becomes a positive value, and when the guide line GD is inclined inward (leftward) about the reference line BL, the deviation angle θ becomes a negative value.

[0077] When the deviation DF is positive, the steering control unit 50b outputs a steering command to the steering device 53 to move the asphalt roller 100 rightward. Similarly, when the deviation DF is negative, the steering control unit 50b outputs a steering command to the steering device 53 to move the asphalt roller 100 leftward.

[0078] In this example, when the deviation angle θ is positive, the steering control unit 50b outputs a steering command to the steering device 53 to rotate the asphalt roller 100 to the right. Similarly, when the deviation angle θ is negative, the steering control unit 50b outputs a steering command to the steering device 53 to rotate the asphalt roller 100 to the left.

[0079] Furthermore, in this example, the steering control unit 50b generates a steering command that can turn the tractor 1 rightward so as to make the deviation amount DF and the deviation angle θ close to zero. In addition, in this example, the position of the right end of the right rear leveler 31R is adjusted so that the right end surface of the newly installed pavement NP is included in the vertical plane including the reference line BL. Therefore, the steering control unit 50b is configured to automatically steer the tractor 1 so that the deviation amount DF becomes zero.

[0080] Furthermore, the screed extension and retraction control unit 50c adjusts the position of the end of the retractable rear screed 31 according to the position of the object detection device 51. Specifically, the screed extension and retraction control unit 50c calculates the position of the object detection device 51 relative to the tractor 1 according to the extension amount of the retractable member TA on which the object detection device 51 is arranged. Similarly, the screed extension and retraction control unit 50c calculates the position of the end of the screed relative to the tractor 1 according to the extension amount of the rear screed 31. The screed extension and retraction control unit 50c calculates the position of the end of the rear screed relative to the object detection device 51 using the calculated position of the object detection device 51, the position of the end of the screed, and the length in the front-to-back direction between the retractable member TA and the rear screed 31. Furthermore, the screed extension and retraction control unit 50c calculates the time until the end of the rear screed 31 reaches the position detected by the object detection device 51 according to the detected travel speed. Then, the screed extension and retraction control unit 50c obtains the posture of the asphalt roller 100 at the time of reaching the position detected by the object detection device 51 based on the control angle, calculates the position of the end of the rear screed 31, and performs extension and retraction control on the rear screed 31. In this way, even if the configuration position of the object AP changes to the left or right in the traveling direction, the screed extension and retraction control unit 50c can make the end of the rear screed 31 follow the configuration position of the object AP.

[0081] Next, refer to Figure 6 Another method of generating a manipulation instruction will be described. Figure 6 is a diagram showing another example of the distance image DM generated based on the output of the stereo camera as the right object detection device 51R, and Figure 5 In addition, Figure 6In the figure, the right object APR is omitted for clarity. Also, the following description is related to the steering command generated based on the output of the right object detection device 51R, but the steering command generated based on the output of the left object detection device 51L is also applicable.

[0082] exist Figure 6 In FIG. 1 , the X axis corresponds to the vehicle length direction of the asphalt roller 100. The Y axis corresponds to the vehicle width direction of the asphalt roller 100. The front axle FX corresponds to the extension line of the wheel axle of the front wheel 6. Figure 6 In the example shown, the right object detection device 51R is arranged to be located further back than the front axle FX in the vehicle length direction (X-axis direction). Specifically, the right object detection device 51R is arranged to be located further back than the front axle FX by a distance Lc from the center point CP of the image DM. The deviation (deviation amount DF) is the distance between the center point CP and the guide line GD in the vehicle width direction (Y-axis direction).

[0083] exist Figure 6 In the example shown, the steering control unit 50b generates a steering command (target steering angle δ) for the steering device 53 based on the guide line GD generated by the guide line generation unit 50a. Specifically, the steering control unit 50b calculates the distance Y' between the target position TP and the X axis based on the distance X' between the target position TP and the front axle FX.

[0084] The distance X' is a value set in advance and functions as a control sensitivity parameter. However, the distance X' can be dynamically set according to the travel speed of the asphalt roller 100. In this case, typically, the distance X' is set to be larger as the travel speed of the asphalt roller 100 increases.

[0085] Specifically, the steering control unit 50b calculates the distance Y' according to the following equation (1): More specifically, the steering control unit 50b calculates the distance Y' according to the deviation amount DF, the distance X', the distance Lc, and the deviation angle θ.

[0086] Y'=DF+(X'+Lc)×tanθ-(1)

[0087] On this basis, the steering control unit 50b calculates the target steering angle δ according to the following equation (2). The target steering angle δ corresponds to the angle formed by the line segment connecting the position ND and the target position TP with respect to the X axis. The position ND is the intersection of the X axis and the front axle FX.

[0088] [Formula 1]

[0089]

[0090] Moreover, the steering control unit 50b uses the calculated target steering angle δ to perform automatic steering. In addition, when the target steering angle δR is generated according to the output Lc of the right object detection device 51R, and the target steering angle δL is generated according to the output Lc of the left object detection device 51L, the steering control unit 50b can use the average value of the target steering angle δR and the target steering angle δL as the final target steering angle δ to perform automatic steering. That is, when only the target steering angle δR can be generated, the steering control unit 50b can use the target steering angle δR to perform automatic steering, and when only the target steering angle δL can be generated, the steering control unit 50b can use the target steering angle δL to perform automatic steering. Alternatively, even in the case where both the target steering angle δR and the target steering angle δL can be generated, the steering control unit 50b can use either the target steering angle δR or the target steering angle δL to perform automatic steering. And, when the target steering angle δR and the target steering angle δL cannot be generated for some reason, the steering control unit 50b can stop the automatic steering. Furthermore, when at least one of the target steering angle δR and the target steering angle δL is generated again after the automatic steering is stopped, the steering control unit 50b may restart the automatic steering.

[0091] Furthermore, the steering control unit 50b can calculate the average deviation, i.e., the average deviation, of the deviation amount DF of the left guide line GDL and the deviation amount DF of the right guide line GDR, and calculate the average deviation angle, i.e., the average deviation angle, of the deviation angle θ of the left guide line GDL and the deviation angle θ of the right guide line GDR, and derive the average guide line from the average deviation amount and the average deviation angle. The average guide line is equivalent to the imaginary center line of the construction width. On this basis, the steering control unit 50b can calculate the target steering angle δ from the average guide line.

[0092] Next, refer to Figure 7 and Figure 8 Another example of the process of generating the guide line GD by the guide line generating unit 50a will be described. Figure 7 1 shows an example of a distance image DM generated based on the output of a stereo camera as the right object detection device 51R. Specifically, Figure 7 (A) represents the distance image DM0 generated at time t0, Figure 7 (B) shows a distance image DM1 generated at time t1 after a predetermined time has passed from time t0. Figure 7 (C) represents a distance image DM2 generated at time t2 after a predetermined time has passed from time t1. Figure 7 (D) represents the distance image DM3 generated at time t3 after a predetermined time has passed from time t2. Figure 7 For clarity, the Figure 5 Illustration of the reference line BL and the orthogonal line TL shown in the figure.

[0093] Figure 8 : is a top view of an asphalt roller that is about to pave a road that curves to the right. Figure 8 The center line CL of the asphalt roller 100 is shown by a dotted line. Figure 8 This indicates that at the current time, that is, time t0, the center line CL of the asphalt roller 100 coincides with the center of the width of the new pavement NP.

[0094] and, Figure 8 In FIG. 1 , the right monitoring range ZR0 corresponding to the distance image DM0 generated at time t0 and the right monitoring range ZR3 corresponding to the distance image DM3 generated at time t3 are indicated by dotted lines. Figure 8 In the figure, the object detection device 51 and the mounting member 60 are omitted for clarity. In addition, the right monitoring range ZR1 (not shown) corresponding to the distance image DM1 generated at time t1 and the right monitoring range ZR2 (not shown) corresponding to the distance image DM2 generated at time t2 are actually located between the right monitoring range ZR0 and the right monitoring range ZR3, but Figure 8 For the sake of clarity, their illustration is omitted.

[0095] In addition, Figure 7 and Figure 8 In the illustrated example, for ease of explanation, the asphalt roller 100 continues to move straight until the distance image DM3 is generated, but in practice it may be automatically manipulated each time the distance image DM is generated.

[0096] At time t0, if Figure 7 As shown in (A), the guide line generation unit 50a generates a right guide line GDR corresponding to the upper left edge of the paving template APR1, one of the right objects APR, based on the distance image DM0. Then, the steering control unit 50b calculates the value DF0 of the deviation amount DF between the reference line BL and the right guide line GDR, and calculates the value of the deviation angle θ formed between the reference line BL and the right guide line GDR to be zero. Therefore, at time t0, the steering control unit 50b does not need to generate a steering command to turn the tractor 1 to the right or left direction, and the tractor 1 continues to move straight.

[0097] At time t1, if Figure 7As shown in (B), the guide line generation unit 50a generates a right provisional guide line PG1 corresponding to the upper left edge of the paving frame APR1 of one of the right objects APR, and generates a right provisional guide line PG2 corresponding to the upper left edge of the paving frame APR2 of the other right object APR based on the distance image DM1. The paving frame APR2 is a paving frame arranged adjacent to the paving frame APR1, and is arranged to be inclined relative to the paving frame APR1 corresponding to the road curving to the right. That is, Figure 7 and Figure 8 The right object APR shown is arranged to be bent at the junction between the paving formwork APR1 and the paving formwork APR2.

[0098] The right provisional guide line PG1 is an imaginary line corresponding to the upper left edge of the portion of the paving template APR1 that enters the right monitoring range ZR1 (not shown). Figure 7 Similarly, the right provisional guide line PG2 is an imaginary line corresponding to the upper left edge of the portion of the paving template APR2 that enters the right monitoring range ZR1 (not shown). Figure 7 In (B), it is indicated by a single-dot chain line.

[0099] When the right tentative guiding line PG1 is generated, the guiding line generating unit 50a calculates the midpoint BM1 of the right tentative guiding line PG1. Similarly, when the right tentative guiding line PG2 is generated, the guiding line generating unit 50a calculates the midpoint FM1 of the right tentative guiding line PG2.

[0100] On this basis, the guide line generation unit 50a generates an imaginary line passing through the midpoint BM1 and the midpoint FM1 as the right guide line GDR1. Then, the steering control unit 50b calculates the value DF1 (> value zero) of the deviation amount DF between the baseline BL and the right guide line GDR1, and calculates the value θ1 (> value zero) of the deviation angle θ formed between the baseline BL and the right guide line GDR1. At this moment, the steering control unit 50b can generate a steering instruction for aligning the right guide line GDR1 with the baseline BL based on the deviation amount DF and the deviation angle θ.

[0101] At time t2, if Figure 7 As shown in (C), the guide line generation unit 50a generates a right tentative guide line PG1 corresponding to the upper left edge of the paving frame APR1 and generates a right tentative guide line PG2 corresponding to the upper left edge of the paving frame APR2 based on the distance image DM2.

[0102] The right provisional guide line PG1 is an imaginary line corresponding to the upper left edge of the portion of the paving template APR1 that enters the right monitoring range ZR2 (not shown). Figure 7Similarly, the right provisional guide line PG2 is an imaginary line corresponding to the upper left edge of the portion of the paving template APR2 that enters the right monitoring range ZR2 (not shown). Figure 7 In (C), it is indicated by a single dotted line. Figure 7 (B) is shorter than that of the right provisional guide line PG2. Figure 7 (B) is longer than the time.

[0103] When the right tentative guiding line PG1 is generated, the guiding line generating unit 50a calculates the midpoint BM2 of the right tentative guiding line PG1. Similarly, when the right tentative guiding line PG2 is generated, the guiding line generating unit 50a calculates the midpoint FM2 of the right tentative guiding line PG2.

[0104] On this basis, the guide line generation unit 50a generates an imaginary line passing through the midpoint BM2 and the midpoint FM2 as the right guide line GDR2. Then, the steering control unit 50b calculates the value DF2 (> value DF1) of the deviation amount DF between the baseline BL and the right guide line GDR2, and calculates the value θ2 (> value θ1) of the deviation angle θ formed between the baseline BL and the right guide line GDR2. At this moment, the steering control unit 50b can generate a steering instruction for aligning the right guide line GDR2 with the baseline BL based on the deviation amount DF and the deviation angle θ.

[0105] At time t3, if Figure 7 As shown in (D), the guide line generation unit 50a generates a right tentative guide line PG1 corresponding to the upper left edge of the paving frame APR1 and generates a right tentative guide line PG2 corresponding to the upper left edge of the paving frame APR2 based on the distance image DM3.

[0106] The right provisional guide line PG1 is the right monitoring range ZR3 (reference Figure 8 . ) corresponds to the imaginary line on the upper left edge of the part inside Figure 7 Similarly, the right provisional guide line PG2 is in line with the right monitoring range ZR3 (reference Figure 8 . ) corresponds to the imaginary line on the upper left edge of the part inside Figure 7 In (D), it is indicated by a single dotted line. Figure 7 (C) is shorter than that of the right provisional guide line PG2. Figure 7 (C) is longer than the previous time.

[0107] When the right tentative guiding line PG1 is generated, the guiding line generating unit 50a calculates the midpoint BM3 of the right tentative guiding line PG1. Similarly, when the right tentative guiding line PG2 is generated, the guiding line generating unit 50a calculates the midpoint FM3 of the right tentative guiding line PG2.

[0108] On this basis, the guide line generation unit 50a generates an imaginary line passing through the midpoint BM3 and the midpoint FM3 as the right guide line GDR3. Then, the steering control unit 50b calculates the value DF3 (> value DF2) of the deviation amount DF between the baseline BL and the right guide line GDR3, and calculates the value θ3 (> value θ2) of the deviation angle θ formed between the baseline BL and the right guide line GDR3. At this moment, the steering control unit 50b can generate a steering instruction for aligning the right guide line GDR3 with the baseline BL based on the deviation amount DF and the deviation angle θ.

[0109] Thus, even when the object AP is bent, the guide line generation unit 50a can generate a guide line GD passing through each midpoint by generating two tentative guide lines. In addition, the guide line generation unit 50a can generate three or more tentative guide lines and generate a guide line GD based on the positions of the midpoints of the three or more tentative guide lines.

[0110] Furthermore, in the above example, the guide line GD is generated as a straight line, but may be generated as a curved line.

[0111] And, reference Figures 5 to 8 The above description is related to the processing performed by the control unit 50b when the width of the newly installed pavement NP does not change due to the advancement of the asphalt roller 100. In other words, the above description is related to the processing performed by the control unit 50b when the left guide line GDL and the right guide line GDR extend substantially in parallel. This is because, when the width of the newly installed pavement NP changes due to the advancement of the asphalt roller 100, if the control unit 50b automatically controls the tractor 1 in such a way that the deviation angle θ between the right guide line GDR and the reference line BL approaches the value of zero, the deviation angle θ between the left guide line GDL and the reference line BL cannot be approached to the value of zero.

[0112] Therefore, when the width of the newly installed pavement NP changes due to the advancement of the asphalt roller 100, the control control unit 50b can be configured to automatically control the tractor 1 while automatically extending and retracting the rear leveler 31. Fig. 9 As shown, when the road to be paved has a widened portion on the left side (widened portion WD indicated by a cross pattern), the steering control unit 50b may be configured to automatically steer the tractor 1 while automatically extending and retracting the rear leveler 31.

[0113] Fig. 9It is a top view of the paving site. Specifically, Fig. 9 In FIG. 1 , a center line L1 of the planned paving area excluding the width W1 of the widening portion WD is indicated by a single-dot chain line, and a center line L2 of the planned paving area including the width W2 of the widening portion WD is indicated by a double-dot chain line. Fig. 9 In FIG. 1 , a track TR that follows the center point of the asphalt roller 100 in order to properly pave the planned paving area is shown by a thick solid line. Fig. 9 The widening portion WD includes the first widening portion WD1 to the third widening portion WD3. The first widening portion WD1 is a portion where the pavement width is expanded, the second widening portion WD2 is a portion where the pavement width is maintained, and the third widening portion WD3 is a portion where the pavement width gradually narrows. Fig. 9 In the figure, for the sake of clarity, the object detection device 51 and the mounting component 60 are omitted.

[0114] Specifically, Fig. 9 The following situation is shown, that is, when the front end of the rear screed 31 reaches the position indicated by the block arrow AR10, the controller 50 extends the left rear screed 31L and the right rear screed 31R according to the positions of the left ground object (left object APL) and the right ground object (right object APR) detected by the object detection device 51, and moves the asphalt roller 100 to the left side (+Y side) in the vehicle width direction, thereby appropriately paving the first widened portion WD1. And, Fig. 9 The following situation is shown, that is, when the front end of the rear screed 31 reaches the position indicated by the block arrow AR11, the controller 50 stops the extension of the rear screed 31 and makes the asphalt roller 100 go straight, thereby appropriately paving the second widened portion WD2. At this time, the controller 50 can detect the ends of the left rear screed 31L and the right rear screed 31R based on the detection value of the object detection device 51. In addition, the asphalt roller 100 can be equipped with an object detection device different from the object detection device 51 in order to detect the ends of the left rear screed 31L and the right rear screed 31R.

[0115] and, Fig. 9 The following situation is shown, that is, when the front end of the rear side screed 31 reaches the position indicated by the block arrow AR12, the controller 50 retracts the left rear side screed 31L and the right rear side screed 31R according to the positions of the left side ground objects and the right side ground objects detected by the object detection device 51, and moves the asphalt roller 100 to the right side (-Y side) in the vehicle width direction, thereby properly paving the third widened portion WD3.

[0116] and, Fig. 9The following situation is shown, that is, when the front end of the rear side screed 31 reaches the position indicated by the block arrow AR13, the controller 50 stops the contraction of the rear side screed 31, and the asphalt roller 100 moves straight, thereby properly paving the predetermined paving area of ​​the width W1 excluding the widening portion WD.

[0117] In such Fig. 9 In the example shown, the guide line generator 50a generates the right guide line GDR based on the distance image generated based on the output of the right object detector 51R, and generates the left guide line GDL based on the distance image generated based on the output of the left object detector 51L.

[0118] Then, the controller 50 calculates the total width of the scheduled paving area based on the information related to the left guide line GDL and the right guide line GDR, respectively. The manipulation control unit 50b can determine whether the width of the scheduled paving area changes based on the change in the calculated total width. In addition, the controller 50 can generate a guide line GD based on the positions of the left and right ground objects detected by the object detection device 51, and extend or retract the leveler 3 based on the generated guide line GD. At this time, the controller 50 can extend or retract the rear leveler 31 without performing automatic manipulation. Alternatively, the controller 50 can extend or retract the rear leveler 31 based on the time series data of the deviation (deviation amount DF) and the predicted result of the walking trajectory of the tractor 1. In addition, the controller 50 can detect the positions of the ends of the left rear leveler 31L and the right rear leveler 31R based on the detection value of the object detection device 51, and can also detect the positions of the ends of the left rear leveler 31L and the right rear leveler 31R based on the detection value of the leveler extension and retraction amount sensor.

[0119] The controller 50 may be configured to calculate the total width of the planned paving area based on the output of the sensor that detects the amount of expansion and contraction of the retractable mounting member 60. At this time, the controller 50 may be configured, for example, to automatically expand and contract the mounting member 60 so that the center point CP of the distance image DM is located on the guide line GD. Furthermore, the controller 50 may calculate the distance between the tractor 1 and the center point of the object detection device 51 based on the output of the sensor that detects the amount of expansion and contraction of the mounting member 60. Furthermore, the controller 50 may calculate the total width of the planned paving area based on pre-stored information related to the total width of the tractor 1, information related to the distance between the left end of the tractor 1 and the center point of the left object detection device 51L, and information related to the distance between the right end of the tractor 1 and the center point of the right object detection device 51R.

[0120] Alternatively, when the object detection device 51 is directly mounted on the tractor 1, the controller 50 may calculate the total width of the scheduled paving area based on the distance between the object detection device 51 and the object AP (ground object) detected by the object detection device 51. Specifically, the controller 50 may calculate the total width of the scheduled paving area based on pre-stored information related to the total width of the tractor 1, information related to the distance between the left object detection device 51L and the left object APL (left ground object) detected by the left object detection device 51L, and information related to the distance between the right object detection device 51R and the right object APR (right ground object) detected by the right object detection device 51R.

[0121] Furthermore, when it is determined that the width of the scheduled paving area has changed, the control unit 50b automatically controls the tractor 1 so that the asphalt roller 100 is located at the center of the scheduled paving area. Specifically, the control unit 50b automatically controls the tractor 1 so that the center point of the asphalt roller 100 follows the track TR (reference Fig. 9 . ) The track TR is a line that depicts the midpoint of the width of the planned paving area.

[0122] Furthermore, the controller 50 can extend or retract the left rear leveler 31L so that the left end of the left rear leveler 31L is consistent with the left end of the planned paving area, and extend or retract the right rear leveler 31R so that the right end of the right rear leveler 31R is consistent with the right end of the planned paving area. At this time, the controller 50 can extend or retract the left rear leveler 31L and the right rear leveler 31R so that the extension amount (protrusion amount) of the left rear leveler 31L is equal to the extension amount (protrusion amount) of the right rear leveler 31R. This is because the density of the newly installed paving body NP becomes uniform throughout the entire width, thereby ensuring the flatness of the newly installed paving body NP.

[0123] Furthermore, the controller 50 may be configured to control the extension and contraction amount of the rear screed machine 31 by additionally considering at least one of the inner and outer wheel difference of the asphalt roller 100 calculated based on the steering angle and the distance between the object detection device 51 and the rear screed machine 31. According to this configuration, the controller 50 can adjust the width of the newly installed pavement NP with high accuracy, thereby improving the quality of the end of the newly installed pavement NP. Furthermore, according to this configuration, the controller 50 does not need to adjust the thickness of the end of the newly installed pavement NP, thereby reducing the number of workers involved in the paving work.

[0124] As described above, the asphalt roller 100 involved in the embodiment of the present invention includes: a tractor 1; a hopper 2, which is provided at the front side of the tractor 1 and receives paving materials; a conveyor CV, which supplies the paving materials PV in the hopper 2 to the rear side of the tractor 1; a screw SC, which spreads the paving materials PV supplied by the conveyor CV at the rear side of the tractor 1; a leveler 3, which evenly spreads the paving materials PV spread by the screw SC at the rear side of the screw SC; an object detection device 51, which obtains information related to ground objects existing within a specified range of the ground of the construction object; and a controller 50 as a control device, which generates a guide line GD as a target line according to changes in the ground objects, and operates the tractor 1 according to the guide line GD.

[0125] The controller 50 can generate a guide line GD as a target line according to changes in the ground features, and steer the tractor 1 according to the guide line GD and a reference line BL indicating the vehicle length direction of the tractor 1. The vehicle length direction of the tractor 1 is a direction perpendicular to the vehicle width direction of the tractor 1.

[0126] The predetermined range is a range having a predetermined front-rear width and a predetermined left-right width with the reference point as the center. The reference point is a point that serves as a reference for determining the content of the current operation command, and is, for example, the center point CP of the distance image DM.

[0127] The specified front-to-back width is set so that information related to the pavement width ahead in the vehicle length direction can be obtained in advance. The larger the front-to-back width (especially the front-to-back width of the range that exists in front of the reference point), the more the controller 50 can obtain in advance information related to the pavement width further ahead. In addition, the specified left-right width is also set so that information related to the pavement width ahead in the vehicle length direction can be obtained in advance. The larger the left-to-right width (especially the left-to-right width of the range that exists in front of the reference point), the more accurately the controller 50 can obtain information related to the pavement width ahead. This structure can achieve more appropriate automatic operation that takes into account changes in the pavement width ahead.

[0128] Ground objects include, for example, a roadbed BS and an object AP existing outside the roadbed BS. Object AP is, for example, a paving formwork, an L-shaped side channel block, a curbstone, or an existing paving body. Ground objects may be ground objects with almost no thickness, such as a line drawn on the ground, a tape attached to the ground, or a rope extending along the ground. Information related to ground objects may include, for example, the properties of the ground objects detected in a non-contact manner by the object detection device 51, such as the height of the ground object, the color of the ground object surface, or the reflectivity of the ground object surface. Changes in ground objects may include, for example, changes in the height of the ground object, changes in the color of the ground object surface, changes in the shape of the ground object, or changes in the reflectivity of the ground object surface. The shape of the ground object may be, for example, a continuous strip shape.

[0129] The controller 50 can, for example, generate a distance image based on the output of the object detection device 51, and derive a position where the height of the ground object changes (for example, a position where the edge of the paving form exists) in the distance image to generate a guide line GD. Furthermore, the controller 50 can, for example, automatically operate the tractor 1 so that the guide line GD in the distance image coincides with the reference line BL.

[0130] According to this structure, the controller 50 can automatically control the tractor 1 more appropriately. Therefore, this structure can reduce the number of workers involved in the paving work, thereby reducing the cost of the paving work. In addition, this structure can appropriately perform the paving work without being affected by the proficiency of the workers. In other words, this structure can achieve uniformity of construction quality, thereby improving construction quality and maintaining high construction quality.

[0131] The controller 50 may be configured, for example, to manipulate the tractor 1 so that the guide line GD coincides with the baseline BL based on at least one of a distance (deviation amount DF) between the guide line GD and the baseline BL in the vehicle width direction and an angle (deviation angle θ) formed between the guide line GD and the baseline BL.

[0132] According to this configuration, the controller 50 can more appropriately and automatically operate the tractor 1. This is because the deviation amount DF represents the deviation between the pavement and the pavement formwork at the current time, and the deviation angle θ represents the deviation between the pavement and the pavement formwork at the future time. That is, the controller 50 can automatically operate the tractor 1 not only to eliminate the deviation at the current time, but also to eliminate the deviation at the future time in advance.

[0133] Furthermore, when paving a straight road, the tractor 1 is automatically controlled based on the deviation amount DF and the deviation angle θ, which can improve the straightness of the tractor 1 compared to the case where the tractor 1 is automatically controlled based on the deviation amount DF alone. Alternatively, when paving a curved road, the tractor 1 is automatically controlled based on the deviation amount DF and the deviation angle θ, which can improve the following performance of the tractor 1 on the curved road compared to the case where the tractor 1 is automatically controlled based on the deviation amount DF alone. This is because the controller 50 can perform automatic control to prevent the occurrence of deviation in advance before the deviation occurs.

[0134] For example, the controller 50 may be configured to generate the guide line GD based on information related to the ground objects before and after the bend when the ground object bends. Figure 8 As shown in FIG. 1 , when the right object APR as a ground feature is bent at the junction between its constituent elements, namely, the paving frame APR1 and the paving frame APR2, as shown in FIG. Figure 7 As shown, the controller 50 can generate the guide line GD based on the information related to the paving form APR1 existing before the paving form APR2 existing after the paving form APR2 is bent. According to this structure, even if the ground feature that may become the basis of the guide line GD is bent or curved, the controller 50 can generate an appropriate guide line GD. Therefore, even if the paving scheduled area is curved in front, the controller 50 can automatically operate the tractor 1 appropriately.

[0135] The change of the above-mentioned ground feature may be, for example, a change in the height of the ground feature. In this case, the controller 50 may generate the guide line GD according to the shape of the ground feature having a height greater than the threshold value TH. Moreover, the threshold value TH may be set to be changeable. According to this structure, the controller 50 can prevent the guide line GD from being erroneously generated according to the shape of the ground feature having a height less than the threshold value TH.

[0136] The controller 50 may be configured to calculate the construction width based on the change of the ground feature existing on the right side of the tractor 1 and the change of the ground feature existing on the left side of the tractor 1. In addition, the construction width is, for example, the total width of the scheduled paving area. For example, the controller 50 may be configured to calculate the construction width based on the position of the portion where the height of the ground feature existing on the left side of the tractor 1 changes (the boundary between the roadbed BS and the left object APL) and the position of the portion where the height of the ground feature existing on the right side of the tractor 1 changes (the boundary between the roadbed BS and the right object APR). According to this structure, the controller 50 can accurately grasp the total width of the scheduled paving area.

[0137] Furthermore, the controller 50 may be configured to operate the tractor 1 so that the center of the tractor 1 is located at the center of the construction width. According to this configuration, the controller 50 can make the extension and retraction amount of the left rear screed 31L and the extension and retraction amount of the right rear screed 31R substantially the same. Therefore, the controller 50 can improve the walking performance (straightness) of the asphalt roller 100.

[0138] The controller 50 can be configured to generate a target line according to the change of the ground object, and to extend and retract the screed machine 3 according to the target line. According to this structure, the controller 50 can extend and retract the screed machine 3 more appropriately. Therefore, this structure can reduce the number of workers involved in the paving work, thereby reducing the cost of the paving work. In addition, this structure can perform the paving work appropriately without being affected by the proficiency of the workers. That is, this structure can achieve uniformity of construction quality, thereby improving the construction quality and maintaining high construction quality.

[0139] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. The above embodiments can be applied to various modifications or substitutions without departing from the scope of the present invention. Furthermore, the features described with reference to the above embodiments can be appropriately combined as long as they are not technically contradictory.

[0140] For example, in the above-mentioned embodiment, the steering device 53 is configured to extend and retract the front wheel steering cylinder provided near the front axle, but when a hydraulic steering motor is used instead of the front wheel steering cylinder, it can be configured to rotate the hydraulic steering motor. In this case, the steering device 53 includes a steering electromagnetic control valve that controls the flow rate of the working oil flowing from the hydraulic pump to the hydraulic steering motor. The steering electromagnetic control valve is configured to be able to control the outflow / inflow of the working oil in the hydraulic steering motor according to the rotation of the steering wheel SH (steering wheel) as the operating device. In addition, the steering electromagnetic control valve is configured to be able to control the outflow / inflow of the working oil in the hydraulic steering motor according to the steering instruction from the controller 50 regardless of the rotation of the steering wheel SH. Alternatively, the steering device 53 can be configured to control an electric motor that automatically rotates the steering wheel SH. In this case, the steering device automatically rotates the steering wheel SH according to the steering instruction from the controller 50, thereby enabling the asphalt roller 100 to be automatically operated.

Claims

1. An asphalt roller, comprising: Tractor; a hopper disposed at a front side of the tractor and receiving paving material; a conveyor for supplying the paving material in the hopper to the rear side of the tractor; a screw that spreads the paving material supplied by the conveyor at the rear side of the tractor; a leveler for evenly spreading the paving material spread by the screw on the rear side of the screw; an object detection device for acquiring information related to a ground object existing within a specified range on the ground of a construction object; and The control device generates a target line according to the change of the ground object, and controls the tractor according to the target line.

2. The asphalt roller according to claim 1, wherein: The control device generates the target line according to the change of the ground feature, and controls the tractor according to the target line and a reference line indicating the vehicle length direction of the tractor.

3. The asphalt roller according to claim 2, wherein: The control device controls the tractor so that the target line coincides with the reference line based on at least one of a distance between the target line and the reference line in a vehicle width direction and an angle formed between the target line and the reference line.

4. The asphalt roller according to claim 2 or 3, wherein: The reference line is set in a direction perpendicular to the axis of the front wheels of the tractor.

5. The asphalt roller according to any one of claims 1 to 4, wherein: When the feature is bent, the control device generates the target line based on information related to the feature before and after the bend.

6. The asphalt roller according to any one of claims 1 to 5, wherein: The change of the ground object is a change in any one of the height, color information, reflectivity or shape of the ground object. The control device generates the target line based on the shape of the feature having a height greater than a threshold value, The threshold value is set to be changeable.

7. The asphalt roller according to any one of claims 1 to 6, wherein: The control device calculates the construction width based on changes in the ground feature existing on the right side of the tractor and changes in the ground feature existing on the left side of the tractor.

8. The asphalt roller according to claim 7, wherein: The control device operates the tractor so that the center of the tractor is located at the center of the construction width.

9. An asphalt roller, comprising: Tractor; a hopper disposed at a front side of the tractor and receiving paving material; a conveyor for supplying the paving material in the hopper to the rear side of the tractor; a screw that spreads the paving material supplied by the conveyor at the rear side of the tractor; a leveler for evenly spreading the paving material spread by the screw on the rear side of the screw; an object detection device for acquiring information related to a ground object existing within a specified range on the ground of a construction object; and A control device is used to extend and retract the screed machine according to changes in the ground objects.

10. The asphalt roller according to claim 9, wherein: The control device extends or retracts the screed machine according to a steering angle of the tractor and a detected travel speed, and the steering angle of the tractor is calculated according to a change in the ground object.

11. The asphalt roller according to claim 9, wherein: The object detection device is configured on the leveling machine.

12. The asphalt roller according to claim 9, comprising: The end leveling device is arranged at the end of the leveling machine. The object detection device is configured on the end leveling device.

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