JP2019152580A - Road surface state detector - Google Patents

Abstract

To provide a road surface state detector with which it is possible to determine whether there is occurrence of a cloud of dust due to the running of the host device.SOLUTION: Provided is a road surface state detector mounted in a work vehicle 1a, comprising a front sensor 21F for detecting a road surface state ahead of the wheel grounding point of a drive wheel and a rear sensor 21R for detecting a road surface state behind the wheel grounding point. The road surface state detector is constituted by including a controller connected to each of the front and the rear sensors, the controller acquiring front output outputted from the front sensor and rear output outputted from the rear sensor, calculating a difference in output value between the front output and the rear output, comparing the calculated difference in output value with a dust determination threshold for determining whether there is occurrence of a cloud of dust, and determining that the road surface state is such that a cloud of dust tends to occur when the difference in output value is greater than or equal to the dust determination threshold.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a road surface condition detection device, and more particularly to a technique for determining whether or not a road surface on which a work vehicle such as a dump truck operating in a mine travels is likely to generate dust.

  In a mine, when a work vehicle such as a dump truck travels, the road surface is shaved with wheels and dust is generated. The dust blocks the field of view of an operator who operates the work vehicle, or deteriorates the recognition performance of an external sensor mounted on the work vehicle for detecting other vehicles, vehicle stops, and the like.

  Therefore, as a technique for reducing the influence of dust on the external sensor, Patent Document 1 states that “a pixel having a luminance value higher than a luminance value for identifying dust among pixels of image data is a high luminance pixel. Detects one pixel of the image data as a central pixel, and detects the central pixel as a non-edge pixel whose luminance value difference with surrounding pixels is lower than the luminance value difference detected as a ground edge In addition, an overlapping pixel where a high-luminance pixel and a non-edge pixel overlap is detected, an area formed by the overlapping pixel is defined as an overlapping pixel area, and the overlapping pixel area is larger than an area for identifying dust. A configuration is disclosed in which an overlapping pixel region is sometimes generated as a dust region, and a screen is drawn so as to identify the dust region for image data (summary extract).

  Further, Patent Document 2 discloses that “a stereo camera device and a two-dimensional camera acquired image acquired by each camera are compared, and an image information that specifies a region without parallax between these two camera acquired images as a parallax-free region”. An acquisition unit, and a vehicle presence region detection unit that identifies a non-parallax region as a vehicle possibility region where there is a high possibility that another vehicle exists when the number of pixels in the parallax-free region in the parallax image is greater than a predetermined value. (Summary Extract) "is disclosed.

International Publication No. 2013/153863 JP 2016-24685 A

  When a work vehicle traveling in the mine raises dust, it affects the following vehicles. Here, if it is possible to detect whether the road surface on which the vehicle is traveling is in a state in which dust is likely to be generated, it is possible to take measures such as spraying water on the road surface to suppress a large amount of dust before the large amount of dust is generated. it can. However, although Patent Documents 1 and 2 can reduce the influence of dust generated in the forward direction of the host vehicle, it is not possible to confirm whether the host vehicle is winding up dust.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to determine whether dust is generated by traveling of the host vehicle.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, a drive wheel, a vehicle body frame mounted on the drive wheel, a vehicle body frame installed on the vehicle body frame, and the drive wheel is a road surface. Mounted on a work vehicle equipped with a front sensor for detecting a road surface state before a wheel ground point that contacts the vehicle and a rear sensor that is installed on the vehicle body frame and detects a road surface state behind the wheel ground point. The road surface state detection device is configured by a controller connected to each of the front sensor and the rear sensor, and the controller includes a front output output from the front sensor and The rear output output from the rear sensor is acquired, the difference between the output values of the front output and the rear output is calculated, and whether the difference between the output values and dust are generated. Comparing the dust determination threshold value for the constant, it determines the difference of the output value is the road surface state dust is likely to occur when a said dust determination threshold above, characterized in that.

  ADVANTAGE OF THE INVENTION According to this invention, it can be determined whether the dust has generate | occur | produced by driving | running | working of the own vehicle. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

External view of dump truck according to the first embodiment The figure which shows the state where the dump truck is traveling while winding up dust Hardware configuration diagram of a dump truck according to the first embodiment Functional block diagram of a road surface state detection device and a road surface state monitoring device according to the first embodiment Flow chart showing the flow of dust detection processing Diagram showing laser incident angle αi The figure which shows the calculation method of laser incident angle (alpha) i about the case where the angle which a scan surface and a road surface make is perpendicular | vertical. The figure which shows the relationship between the front left measurement point, the rear left measurement point, the vehicle speed, and the scan distance Ti. The figure which shows the relationship between the front left measurement point, the rear left measurement point, the vehicle speed, and the scan distance Ti. The figure which shows the laser incident angle in the state where the body frame is pitching External view of dump truck according to second embodiment Hardware configuration diagram of dump truck according to the second embodiment Functional block diagram of a road surface state detection device and a road surface state monitoring device according to the second embodiment Hardware configuration diagram of dump truck according to the third embodiment Functional block diagram of a road surface state detection device and a road surface state monitoring device according to the third embodiment Figure showing an example of rider mounting position

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various modifications by those skilled in the art are within the scope of the technical idea disclosed in this specification. Changes and modifications are possible. In all the drawings for explaining the present invention, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

  In the following description, the dump truck 1 traveling in the mine is described as an example of the work vehicle. However, the work vehicle is not limited to the dump truck 1 and may be a grader or a wheel loader.

<First Embodiment>
In the first embodiment, a single LIDAR (Light Detection and Ranging) is used to extract a set of measurement data that can be considered to have the same laser incident angle from the measurement results obtained in one scan cycle, and the reflected light intensity It is an embodiment for determining whether dust is generated based on the difference. The LIDAR is a sensor that irradiates a laser beam toward an object, receives reflected light of the irradiated laser, and outputs the reflected light intensity of the reflected light. Hereinafter, a first embodiment will be described with reference to the drawings.

  FIG. 1 is an external view of a dump truck 1 according to the first embodiment. FIG. 2 is a diagram illustrating a state where the dump truck 1 is traveling while winding up the dust C. FIG.

  As shown in FIG. 1, the dump truck 1 includes a left front wheel 5FL, a right front wheel 5FR, a left rear wheel 6RL, and a right rear wheel, and a vehicle frame 2 through a suspension on these wheels, A vessel 3 is mounted on the vehicle body frame 2 so as to be undulated. Further, a driver's cab 4 is provided above the front side of the vehicle body frame 2. In addition, a GPS antenna 7 is provided on the deck at the upper front of the body frame 2. The dump truck 1 is a rear wheel drive vehicle, the left front wheel 5FL and the right front wheel 5FR are driven wheels, the left rear wheel 6RL and the right rear wheel are drive wheels.

  Further, the dump truck 1 has the left LIDAR 10L at a position in the vicinity of the left rear wheel 6RL on the left side surface of the body frame 2 and including the road surface A from the front to the rear of the wheel contact point of the left rear wheel 6RL within the scan range. Prepare. Further, a right LIDAR 10R is provided at a position in the vicinity of the right rear wheel on the right side surface of the vehicle body frame 2 where the road surface A from the front to the rear of the wheel contact point of the right rear wheel is included in the scan range.

  The left LIDAR 10L and the right LIDAR 10R are sensors provided for the dump truck 1 to measure road shoulders and surrounding obstacles. In the present embodiment, the LIDAR 10R will be described, but a camera or a distance image sensor may be used. In the present embodiment, the left LIDAR 10L and the right LIDAR 10R are provided in the dump truck 1. For the purpose of detecting whether the road surface A is likely to generate dust C, either the left LIDAR 10L or the right LIDAR 10R is used. Or just one. Therefore, in the following description, the process of detecting the road surface state using only the output of the left LIDAR 10L will be described, but the road surface state may be detected using only the output of the right LIDAR 10R. Hereinafter, the left LIDAR 10L will be mainly described as an example, but the same effect can be obtained even if the left LIDAR 10R is replaced.

  As shown in FIG. 2, when the road surface A is dry soil, the dust C is picked up by the rotation of the left rear wheel 6RL between the left LIDAR 10L and the road surface. The dust C is also wound up by the rotation of the left front wheel 5FL which is a driven wheel, but more dust C is wound up by the left rear wheel 6RL and the right rear wheel which are driving wheels. That is, more dust C is rolled up behind the wheel contact point of the drive wheel, that is, the left rear wheel contact point C_RL. Therefore, in the present embodiment, generation of dust C is determined based on the output difference of the left LIDAR 10L before and after the left rear wheel ground contact point C_RL.

  The left LIDAR 10L is more dumped than the left rear wheel contact point C_RL where the front end of the left road straight line XL formed by the intersection of the scan surface 11L formed by the laser irradiation surface of the left LIDAR 10L and the road surface A is in contact with the road surface A. It is attached to the vehicle body frame 2 so that it is in the forward direction of the truck 1 and the rear end is behind the left rear wheel ground contact point C_RL in the forward direction of the dump truck 1. The front left measurement point 11L_i in front of the left rear wheel ground contact point C_RL corresponds to the front measurement point, and the rear left measurement point 11L_i + m behind the left rear wheel ground contact point C_RL corresponds to the rear measurement point. That is, in the first embodiment, the left LIDAR 10L outputs both the front output and the rear output, and realizes the functions of both the front sensor and the rear sensor.

  As a result, a single left LIDAR 10L measures a road surface A that has less or no influence of dirt C in front of the left rear wheel ground contact point C_RL, and rolls up after traveling behind the left rear wheel ground contact point C_RL. The road surface A can also be measured through the dirt C.

  Further, when the left LIDAR 10L is installed at the lower portion of the dump truck 1, the detection surface of the left LIDAR 10L may be soiled. However, by attaching the dump truck 1 to the upper left side of the dump truck 1, particularly the upper left rear wheel 6RL on the left side, it is possible to suppress the frequency with which the dust C soared adheres to the detection window of the left LIDAR 10L.

  Similarly, in the right LIDAR 10R, the right road surface straight line XR is the right rear behind the direction in which the dump truck 1 travels from the right wheel contact point from the right front contact point 11R_i before the right wheel contact point where the right front wheel 5FR contacts the road surface A. It is attached to the vehicle body frame 2 so as to have a position and a scan angle including the measurement point 11R_i + m.

  FIG. 3 is a hardware configuration diagram of the dump truck 1. The dump truck 1 travels on a conveyance path provided in the mine. A control center 200 is installed in the mine, and performs traffic control of work vehicles traveling in the mine including the dump truck 1.

  The dump truck 1 communicates with the left LIDAR 10L, the right LIDAR 10R, the vehicle speed sensor 20, the road surface state detection device 100, the self-position calculation device 120 that measures the position / posture of the dump truck 1, and the control center 200. A communication device 130 is installed.

  The road surface state detection apparatus 100 includes a CPU 101, a ROM 102, a RAM 103, an HDD 104, an input interface (I / F) 105, and an output I / F 106, which are configured using a controller (computer) connected to each other via a bus 107. Is done. The control center 200 includes the same configuration as described above. Furthermore, in this embodiment, the clock 108 is included as a hardware configuration of the road surface state detection device 100. The clock 108 only needs to be able to measure the irradiation time of the laser. For example, the clock 108 may be configured using RTC (Real-Time Clock), and may use coordinated universal time as time data.

  The left LIDAR 10L and the right LIDAR 10R, the vehicle speed sensor 20, and the self-position calculation device 120 are connected to the input I / F 105 of the road surface state detection device 100.

  The in-vehicle communication device 130 is connected to the output I / F 106 of the road surface state detection device 100.

  The self-position calculation device 120 may be configured by any one of a GPS (Global Positioning System) 121 and an IMU (Inertial Measurement Device) 122, or a combination thereof. In this embodiment, the GPS 121 and the IMU 122 are mounted, and a position corrector 123 that further corrects the absolute coordinates (or referred to as external coordinates) output from the GPS 121 using the output of the IMU 122 is further included. Since the vehicle body frame 2 is mounted on the wheels via the suspension, the vehicle body posture shifts with respect to the road surface A due to the expansion and contraction of the suspension. Therefore, the output of the IMU 122 includes vehicle body posture data defined by the pitch angle, yaw angle, and roll angle of the vehicle body frame 2 with respect to the road surface A, and the vehicle body posture data is output to the input I / F 105.

  The control center 200 includes a center-side communication device 230 for receiving dust generation data from the in-vehicle communication device 130, and a road surface state monitoring device 210 that monitors the road surface state based on the dust generation data.

  FIG. 4 is a functional block diagram of the road surface state detection device 100 and the road surface state monitoring device 210. The left LIDAR 10L, the right LIDAR 10R, the vehicle speed sensor 20, and the self-position calculation device 120 are connected to the input I / F 105. The road surface condition detection apparatus 100 includes an input I / F 105, a clock 108, a sensor output acquisition unit 111, a laser incident angle calculation unit 112, an output difference calculation unit 113, a dust generation determination unit 114, an output I / F 106, and an identical point output specification. Part 117.

  Further, the road surface state detection device 100 includes a road surface state data storage unit 115, a dust determination threshold storage unit 116, and an inter-sensor distance storage unit 142. These may be configured in a partial area of the RAM 103 or the HDD 104.

  The road surface state monitoring device 210 includes an input I / F 211, a road surface state map creating unit 212, and a road surface state map storage unit 213.

  The function of each part of the road surface state detection device 100 and the road surface state monitoring device 210 will be described later with reference to the processing flow of FIG. Each unit is configured by cooperation of software realizing each function and hardware shown in FIG.

  As another configuration example, the road surface state detection device 100 and the road surface state monitoring device 210 may be configured by using one or a plurality of microcomputer devices that realize the functions shown in FIG.

  Hereinafter, with reference to FIG. 5, a description will be given of a process for detecting the road surface condition, in particular, the ease with which the dust C is generated while the dump truck 1 travels. FIG. 5 is a flowchart showing the flow of the dust detection process.

  While the dump truck 1 is traveling, the left LIDAR 10L gradually changes the laser irradiation angle θi at a predetermined angle, for example, every 0.25 degrees, so that the left rear wheel ground contact point C_RL is directed from the front to the rear. A fan-shaped scan range is formed by sequentially and sequentially irradiating a laser, and reflected light from a measurement point on the road surface A is received.

  In the first embodiment, the left LIDAR 10L measures each of the front left measurement point 11L_i that is in front of the left rear wheel ground contact point C_RL and the rear left measurement point 11L_i + m that is behind the single left scanning cycle. Here, the time difference between the scan times of the front left measurement point 11L_i and the rear left measurement point 11L_i + m is determined by the self-position calculation device 120 and the vehicle body posture scan cycle (for example, approximately once / Therefore, the front left measurement point 11L_i and the rear left measurement point 11L_i + m will be described as being able to be measured almost simultaneously, that is, in the same step S1.

  More specifically, in step S1, a laser is irradiated toward the front left measurement point 11L_i, and the laser reflected light reflected at the front left measurement point 11L_i is received. The left LIDAR 10L is a laser irradiation direction when the laser is irradiated toward the front left measurement point 11L_i, a measurement distance D from the left LIDAR 10L calculated based on the received laser reflected light to the front left measurement point 11L_i, and a laser. The reflected light intensity is measured and output to the road surface condition detection apparatus 100. Similarly, the same applies to the rear left measurement point 11L_i + m (S1). The sensor output acquisition unit 111 acquires a front output obtained by measuring the front left measurement point 11L_i and a rear output obtained by measuring the rear left measurement point 11L_i + m.

  In step S2, the self-position computing device 120 calculates the self-position and outputs self-position data. The sensor output acquisition unit 111 acquires the self-position data and the vehicle body posture data measured by the IMU 122 (S2).

  In step S <b> 3, the sensor output acquisition unit 111 determines the position of the measurement point on the road surface A by the left LIDAR 10 </ b> L in the external coordinate system from the self-position data and the vehicle body posture data and the installation position and attachment angle of the left LIDAR 10 </ b> L with respect to the vehicle body frame 2. And the calculated position and the laser reflected light intensity (corresponding to the sensor output) included in the front output and the rear output are associated with each other and recorded in the road surface state data storage unit 115 (S3). The sensor output acquisition unit 111 acquires time data from the clock 108, associates the sensor output with the acquired time, and outputs it to the laser incident angle calculation unit 112. Therefore, time data is associated with the sensor output after this step. The sensor output acquisition unit 111 acquires the sensor output from the left LIDAR 10L and the right LIDAR 10R, the time when each of the left LIDAR 10L and the right LIDAR 10R irradiates the laser, and each of the left LIDAR 10L and the right LIDAR 10R outputs the sensor output. Although the time is strictly different, the time difference between these times is slightly different compared to the time when the behavior of the dump truck 1 changes. In considering the behavior of the dump truck 1, these times are regarded as the same time. May be. Therefore, in the present embodiment, the time data associated with the sensor output by the sensor output acquisition unit 111 is described as being the same as the time at which the left LIDAR 10L and the right LIDAR 10R each irradiate the laser and measure the road surface.

  In step S <b> 4, the laser incident angle calculation unit 112 obtains a left road surface line XL that is an intersection line between the scan surface 11 </ b> L of the left LIDAR 10 </ b> L and the road surface A from a measurement point group including a set of a plurality of measurement points. The laser incident angle calculation unit 112 calculates the laser incident angle αi from the angle formed by the left road surface line XL and the straight line from the sensor origin to each measurement point and the road surface A at the scan surface 11L and the front left measurement point 11L_i. Is added to the laser reflected light intensity in step S3, and the laser incident angle αi on the road surface at the measurement point by the left LIDAR 10L and the measurement distance D are recorded in the road surface state data storage unit 115 (S4).

  FIG. 6 shows a method for calculating the laser incident angle αi.

  As shown in FIG. 6, the laser incident angle αi is defined as the angle formed between the normal ε of the road surface A (assumed to be a plane) and the laser irradiated to the road surface A. The distance from the laser irradiation point of the left LIDAR 10L to the front left measurement point 11L_i and the rear left measurement point 11L_i + m is represented as a measurement distance D.

As shown in FIG. 7, when the left road surface line XL obtained from the measurement point group on the road surface A measured by the left LIDAR 10L is XL: y = ax + b, the road surface inclination β with respect to the X axis of the sensor coordinate system is expressed by the following formula ( It can be expressed by 1).

Therefore, the laser incident angle αi with respect to the road surface A at the front left measurement point 11L_i of the laser irradiation angle θi can be expressed by the following equation (2).

  In step S <b> 5, the same spot output specifying unit 117 acquires the vehicle speed V measured by the vehicle speed sensor 20 via the input I / F 105. And the same spot output specific | specification part 117 is the difference of the position of a measurement point, and the measurement distance D from the front left measurement point 11L_i and the back left measurement point 11L_i + m among the measurement points memorize | stored in the road surface state data storage part 115. , And a set of measurement points where the differences in the laser incident angles αi are all equal to or less than the threshold (S5).

  The same point output specifying unit 117 has a value obtained by multiplying the time from the first time when the front left measurement point 11L_i is measured to the second time when the rear left measurement point 11L_i + m is measured by the vehicle speed V, the same as or the same as the distance between sensors. A set of the front left measurement point 11L_i and the rear left measurement point 11L_i + m that are within the range that can be considered as follows.

  FIGS. 8 and 9 are diagrams illustrating the relationship between the front left measurement point 11L_i, the rear left measurement point 11L_i + m, the vehicle speed V [m / s], and the scan distance Ti. When the left LIDAR 10L is installed downward at the height H [m] position of the upper part of the left front wheel as shown in FIGS. 8 and 9, measurement in the laser irradiation angle θi direction of the dump truck 1 traveling on the plane at the vehicle speed V is performed. In the measurement in the laser irradiation angle −θi + m direction after 2 H tan θ / V, the position of the measurement point, the measurement distance D (see FIG. 6), and the laser incident angle αi (see FIG. 6) are all the same. The set is extracted in step S5.

  Next, in step S6, the output difference calculation unit 113 obtains a difference in laser reflected light intensity for each set of measurement points extracted in step S5. Here, the amount of dust is estimated based on the difference in reflected light intensity when the measurement point road surface A (the laser reflectivity thereof), the measurement distance D, and the laser incident angle αi are the same, the laser reflected light intensity is on the optical path. This is because the amount of light attenuation due to the dust C depends on the amount of light attenuation, and the amount of light attenuation increases as the amount of dust C increases. If this characteristic is used, the magnitude of the amount of dust can be determined based on the difference in laser reflected light intensity.

  In step S7, the dust generation determination unit 114 determines whether the difference in the laser reflected light intensity obtained in step S6 is equal to or greater than the dust generation threshold stored in advance in the dust determination threshold storage unit 116 (S7). The dust generation threshold may be determined based on, for example, the attenuation amount of the laser reflected light intensity when a dust amount that reduces the recognition performance of the external sensor is generated.

  If the difference in the intensity of the reflected laser light obtained in step S6 is greater than or equal to the dust generation threshold (S7 / Yes), the dust generation determination unit 114 is the front that is the basis for calculating the output value difference that is greater than or equal to the dust determination threshold. Self-position data associated with at least one of the left measurement point 11L_i or the rear left measurement point 11L_i + m is read. Then, data indicating that dust is generated, for example, a flag that is “1” when it is determined that dust is generated, and the position of the measurement point where the difference in laser reflected light intensity is equal to or greater than the dust threshold. Dust generation data including (corresponding to the read self-location data) is generated and output to the in-vehicle communication device 130. The dust generation data may include the laser incident angle αi, the measurement distance D, and the laser reflected light intensity. The in-vehicle communication device 130 transmits dust generation data to the control center 200.

  The center side communication device 230 of the control center 200 receives the dust generation data. In the road surface condition monitoring apparatus 210, the road surface state map creation unit 212 acquires the dust generation data via the input I / F 211, reads the position of the measurement point from the dust generation data, and maps the position of the measurement point to the road surface state map. create. Then, the road surface state map creation unit 212 writes the road surface state map into the road surface state map storage unit 213.

  As described above, in the left LIDAR 10L, the laser irradiation angle θi is gradually changed for each predetermined angle to scan the measurement point, the distance to the road surface A for each predetermined angle, and the laser reflection Measure the light intensity. Therefore, when the left LIDAR 10L is installed on the vehicle body frame 2 so that the scanning surface 11L of the left LIDAR 10L is parallel to the traveling direction of the dump truck 1, the measurement distance D of the measurement point and the laser incident angle αi are the same. There is a set of measurement points, which leads to improved reliability of dust detection.

  FIG. 10 is a diagram showing the laser incident angle αi when the body frame 2 is pitched. As shown in FIG. 10, even when the vehicle body frame 2 is pitched with an angle P with respect to the road surface A, the scanning surface 11 </ b> L of the left LIDAR 10 </ b> L is parallel to the traveling direction of the dump truck 1. When the left LIDAR 10L is installed on the vehicle body frame 2, there is a set of measurement points where the measurement distance D of the measurement points and the laser incident angle αi are the same.

  In the above, since the influence of the dust C on the laser reflected light intensity varies depending on the laser incident angle αi and the measurement distance D, it is preferable that the dust determination threshold value in S7 is changed depending on the laser incident angle αi and the measurement distance D.

  In step S7, it is determined that dust C has been generated if there is at least one pair in which the difference in laser reflected light intensity is equal to or greater than the dust generation threshold, but by comparing the average value or maximum value with the threshold, The generation of dust may be determined.

  According to the present embodiment, the road surface state is caused by the difference in the reflected light intensity of the radar from the measurement points on the road surface A before and the road surface A behind the wheel contact point of the driving wheel of the work vehicle, so that the road surface state is caused by the dust C. It can be determined whether or not the state is likely to occur. Then, by transmitting the determination result to the control center 200, a road surface state map is created. Thereby, it becomes possible for the operator to respond by distributing a watering vehicle with reference to the road surface state map or by restricting the traveling of the dust generation area.

  In the first embodiment, the position of the measurement point is obtained based on the position / posture of the dump truck 1, the road surface A at the same point is measured before and after the wheel passes, and the laser reflected light intensity is measured. The generation of dust C was determined based on the difference. However, when the road surface A is flat and the characteristics of the laser such as the reflectance are considered to be uniform at any point, there is no need to measure the same point, and a set of measurements in which the laser incident angle αi and the measurement distance D are substantially the same. On the other hand, the generation of dust C may be determined based on the difference in the intensity of the laser reflected light. This eliminates the need to record and use past measurement data such as the intensity of the reflected laser beam, and allows the occurrence of dust C to be detected in real time.

Second Embodiment
The second embodiment uses a plurality of LIDARs to determine whether dust C is generated based on the difference in laser reflected light intensity of measurement data obtained by scanning the same point twice at different times. It is an embodiment.

  FIG. 11 is an external view of a dump truck 1a according to the second embodiment. In the second embodiment, the front LIDAR 21F that measures the road surface A before the left rear wheel ground contact point C_RL (before the left front wheel ground contact point C_FL in this embodiment) and the rear rear wheel ground contact point C_RL. A plurality of LIDARs including a rear LIDAR 21R that measures the road surface A are provided. In the example of FIG. 11, the front LIDAR 21 </ b> F is installed on a deck installed in the front part of the vehicle body frame 2. The rear LIDAR 21R is installed on the side surface of the body frame 2 and behind the left rear wheel 6RL.

  FIG. 12 is a hardware configuration diagram of the dump truck 1a according to the second embodiment. FIG. 13 is a functional block diagram of the road surface state detection device 100 and the road surface state monitoring device 210 according to the second embodiment. In the second embodiment, each of the front LIDAR 21F and the rear LIDAR 21R is connected to the input I / F 105. The front LIDAR 21F and the rear LIDAR 21R may be sensors capable of measuring only one point on the road surface, that is, the laser irradiation direction.

  Then, based on the measurement data (front output and rear output) output by the front LIDAR 21F and the rear LIDAR 21R, the same spot output specifying unit 117 is different between the front LIDAR 21F and the rear LIDAR 21R, which are composed of different sensors, as in the first embodiment. A set of measurement data obtained by measuring the same point on the road surface A is specified from the measurement data output by each other. The output difference calculation unit 113 calculates the difference between the measurement data (front output and rear output) included in this set, and the dust generation determination unit 114 determines the generation of dust based on this difference. The road surface state detection device 100 according to the present embodiment may have the same configuration as the road surface state detection device 100 of the first embodiment, and the difference is extracted from the road surface state data storage unit 115 by the same point output specifying unit 117. In the first embodiment, the measurement data is a set of measurement data obtained by measuring the same point at different times by the same sensor, whereas in the second embodiment, different sensors measure the same point at different times. It is a point that is a set of measurement data obtained. However, the processing in the other road surface condition detection apparatus 100 is the same as that in the first embodiment, except that the sensors that output each set of measurement data are different.

  According to the present embodiment, generation of dust C is determined based on data obtained by measuring the same point on the road surface A at different times using a plurality of sensors whose laser irradiation directions are one direction as in the first embodiment. Can be done.

<Third Embodiment>
The third embodiment is an embodiment in which the same point as the point measured by the front LIDAR 21F is actively measured by the rear LIDAR 21R to determine whether dust C is generated. The LIDAR used in the first embodiment and the second embodiment has been described using a sensor that outputs data at a constant period. However, the LIDAR used in this embodiment has a signal (command) instructing laser irradiation. It is a sensor that receives and irradiates a laser.

  Since the appearance of the dump truck 1b according to the third embodiment is the same as that of the second embodiment, the description thereof is omitted.

  A third embodiment will be described with reference to FIGS. 14 and 15. FIG. 14 is a hardware configuration diagram of the dump truck 1b according to the third embodiment. FIG. 15 is a functional block diagram of the road surface state detection device 100b and the road surface state monitoring device 210 according to the third embodiment.

  As shown in FIG. 14, in this embodiment, a front LIDAR 21 </ b> F and a rear LIDAR 21 </ b> R are connected to the output I / F 106.

  As shown in FIG. 15, the road surface state detection device 100 b according to the present embodiment includes a timing calculation unit 141 and a laser irradiation signal generation unit 143.

  In the present embodiment, each of the front LIDAR 21F and the rear LIDAR 21R measures one point on the road surface A. The front measurement point 22F of the front LIDAR 21F and the rear measurement point 22R of the rear LIDAR 21R are arranged such that the straight line connecting the front measurement point 22F and the rear measurement point 22R is parallel to the traveling direction when the dump truck 1 is traveling straight. The front LIDAR 21F and the rear LIDAR 21R are attached to the vehicle body frame 2. The distance (inter-sensor distance) between the position where the front LIDAR 21F is attached to the vehicle body frame 2 and the position where the rear LIDAR 21R is attached to the vehicle body frame 2 is stored in the inter-sensor distance storage unit 142.

  The timing calculation unit 141 acquires the sensor output of the forward LIDAR 21F linked to the time data obtained from the clock 108 via the input I / F 105. At the same time, the vehicle speed V is also acquired.

  Next, the timing calculation unit 141 reads the inter-sensor distance from the inter-sensor distance storage unit 142. If the dump truck 1b travels on a horizontal plane, and the scan angle of the front LIDAR 21F and the rear LIDAR 21R is the same angle with respect to the horizontal plane or the vehicle body frame 2, the distance between the sensors is the front measurement point 22F on the horizontal plane and the rear It may be regarded as the same as the interval (scan distance) Ti of the measurement points 22R. Therefore, in the present embodiment, the distance between sensors will be described as the scan distance Ti.

  When the vehicle speed V of the dump truck 1 is assumed, the timing calculation unit 141 calculates a timing lag Δt by dividing the scan distance Ti by the vehicle speed V, and corresponds to the timing lag Δt from the first time when the front LIDAR 21F measures the front measurement point 22F. Is calculated as the laser irradiation timing of the rear LIDAR 21R, and the calculation result is output to the laser irradiation signal generation unit 143.

  The laser irradiation signal generation unit 143 outputs a signal for measuring the road surface A at the second time to the rear LIDAR 21R via the output I / F 106, that is, for irradiating the laser.

  The rear LIDAR 21R outputs the sensor output obtained by measuring the road surface A at the second time to the input I / F 105.

  The road surface state data storage unit 115 stores, as needed, measurement data obtained by measuring the same point on the rear LIDAR 21R with a delay of Δt from the measurement data measured on the road surface by the front LIDAR 21F at the first time. Therefore, the same spot output specifying unit 117 extracts a set of measurement data obtained by measuring the same spot at different times, and outputs it to the output difference calculating unit 113. The subsequent processing is the same as in the first and second embodiments. The laser irradiation signal generation unit 143 also outputs a signal for irradiating the front LIDAR 21F with the laser at the first time. The laser irradiation signal generation unit 143 may use any method for determining the first time, and the present embodiment is characterized in that the second time is determined based on the first time.

  According to the present embodiment, it is possible to improve the determination accuracy of dust generation by actively controlling the rear LIDAR 21R to measure the same point as the point measured by the front LIDAR 21F.

  The present invention is not limited to the embodiments described above, and includes various modifications. The above-described embodiments are for explaining the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to only having all the configurations described.

  For example, when the road surface state detection device 100 executes the dust detection process using both the left LIDAR 10L and the right LIDAR 10R, when it is determined that dust is generated in at least one of the left LIDAR 10L or the right LIDAR 10R, You may comprise so that dust generation data may be output.

  In the above description, the clock 108 is provided and the above processing is executed using the time data. However, the time data may be a time with an offset such as the activation time of the CPU 101. In addition to the clock of the CPU 101, a time stamp of data output from each LIDAR may be used. In this case, the time data is data from sensor activation.

  Further, in the above description, the vehicle speed sensor 20 is provided and the same point is specified using the vehicle speed V. However, when there is a self-position calculating device 120, the same point is specified based on the self-position calculated by the self-position calculating device 120. May be performed. In this case, the vehicle speed sensor is not essential.

  Further, in this embodiment, the front and rear of the wheel contact point of the driven wheel are measured using the characteristic that the dust C is more likely to be generated from the drive wheel than the driven wheel. May be detected.

  Also, a rider as a rear sensor, for example, the left rider 10L in the first embodiment is attached to the vehicle body frame 2 so as to be able to measure the front and rear of the left rear wheel ground contact point C_RL. For example, as shown in FIG. 16, the mounting position may be at the rear of the deck or on the side of the hydraulic oil tank. Moreover, the rear part of the vehicle body frame 2 may be used.

1: Dump truck 100: Road surface state detection device 120: Self-position calculating device 130: In-vehicle communication device 200: Control center 210: Road surface state monitoring device 230: Center side communication device A: Road surface

Claims (9)

A driving wheel; a vehicle body frame mounted on the driving wheel; a front sensor that is installed on the vehicle body frame and detects a road surface state before a wheel contact point where the driving wheel contacts the road surface; and the vehicle body frame A road surface state detection device mounted on a work vehicle, and a rear sensor that detects a road surface state behind the wheel contact point,
The road surface condition detection device is constituted by a controller connected to each of the front sensor and the rear sensor,
The controller is
Obtaining a front output outputted from the front sensor and a rear output outputted from the rear sensor;
Calculating a difference between output values of the front output and the rear output;
Compare the difference between the output values and the dust determination threshold for determining whether dust is generated,
When the difference between the output values is equal to or greater than the dust determination threshold, it is determined that the road surface state is likely to generate dust.
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 1,
The drive wheel is a rear wheel of the work vehicle;
The controller acquires a front output that detects a road surface state before the wheel grounding point of the rear wheel, and a rear output that detects a road surface state behind the wheel grounding point of the rear wheel,
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 1,
Each of the front sensor and the rear sensor is configured using a sensor that irradiates a laser toward the road surface, receives reflected light of the irradiated laser, and outputs the reflected light intensity of the reflected light,
The rear sensor is installed at the same height as the front sensor to the road surface,
The controller calculates a difference between the reflected light intensity indicated by the front output and the reflected light intensity indicated by the rear output as the difference between the output values.
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 3,
The front sensor is installed in front of the wheel contact point in the body frame,
The rear sensor is installed behind the wheel contact point in the body frame,
The controller includes the front output obtained by measuring the front measurement point on the road surface before the wheel contact point by the front sensor, and a first time when the front sensor measures the front measurement point. At the second time later, the rear sensor obtains the rear output obtained by measuring a rear measurement point on the road surface behind the wheel contact point.
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 4,
Each of the front sensor and the rear sensor is a sensor that periodically irradiates a laser,
The controller is further connected to a vehicle speed sensor that measures the vehicle speed of the work vehicle mounted on the work vehicle, and includes a clock that measures the irradiation time of a periodically irradiated laser,
Storing the inter-sensor distance from the position of the front sensor attached to the body frame to the position of the rear sensor attached to the body frame;
A value obtained by multiplying the time from the first time at which the front output is measured to the second time at which the rear output is measured by the vehicle speed acquired from the vehicle speed sensor is the same as the distance between the sensors. Identify a set of outputs and the output of the rear sensor;
Calculating a difference between the front output and the rear output included in the set;
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 4,
The work vehicle further includes a vehicle speed sensor that measures a vehicle speed of the work vehicle,
Each of the front sensor and the rear sensor is a sensor that performs measurement by irradiating the laser according to a signal for irradiating the laser,
The controller is further connected to the vehicle speed sensor, and includes a clock for measuring an irradiation time when the front sensor and the rear sensor irradiate a laser,
Dividing the distance between the position of the front sensor attached to the vehicle body frame and the position of the rear sensor attached to the vehicle body frame by the vehicle speed obtained from the vehicle speed sensor to calculate the timing lag,
The second time later than the first time measured by the front sensor is calculated as the timing at which the rear sensor irradiates the laser.
Generating an irradiation signal for irradiating the rear sensor with a laser at the second time, and outputting to the rear sensor;
The rear sensor receives the irradiation signal and irradiates a laser.
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 1,
Each of the front sensor and the rear sensor sequentially irradiates the road surface with laser from the front to the rear, and the vehicle body is oriented in a direction in which a scan surface formed by the laser irradiation surface is parallel to the traveling direction of the work vehicle. Consists of one rider installed on the frame,
The front end of the road surface straight line where the scan surface of the rider and the road surface intersect is ahead of the wheel contact point, and the rear end of the road surface line is behind the wheel contact point,
The controller includes a front output obtained by measuring a front measurement point before the wheel contact point during one scan of the rider, and a laser for measuring the front measurement point with respect to the road surface. Obtaining a rear output obtained by measuring a rear measurement point behind the wheel contact point at the same laser incident angle as the incident angle;
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 7,
The controller is further connected to a vehicle speed sensor that measures the vehicle speed of the work vehicle mounted on the work vehicle, and includes a clock that measures the irradiation time of a periodically irradiated laser,
The rider outputs the result of measuring the front measurement point at the first time as the front output, and the result of measurement at the second time after the driving wheel passes the front measurement point as the rear output. Output,
The controller is
Pre-stores the inter-sensor distance from the position of the front sensor attached to the body frame to the position of the rear sensor attached to the body frame;
A value obtained by multiplying the time from the first time at which the front output is measured to the second time at which the rear output is measured by the vehicle speed acquired from the vehicle speed sensor is the same as the distance between the sensors. Identify a set of outputs and the output of the rear sensor;
Calculating a difference between the front output and the rear output included in the set;
A road surface condition detection device characterized by the above. The road surface condition detection device according to claim 1,
The work vehicle has a self-position calculation device that calculates self-position and outputs self-position data;
An in-vehicle communication device that transmits to a road surface state monitoring device that monitors a road surface state on which the work vehicle travels, and
The controller is connected to each of the self-position calculation device and the in-vehicle communication device,
The controller is
Obtaining the self-position data of the work vehicle from the self-position computing device;
Record road surface state data that associates the front output, the rear output, and the self-position data,
When it is determined that the difference between the output values is equal to or greater than the dust determination threshold, the front output or the rear is used as a basis for calculating the difference between the output values that is equal to or greater than the dust determination threshold with reference to the road surface state data. Reading the self-location data associated with at least one of the outputs;
Generating dust generation data including data indicating that the difference between the output values is equal to or greater than the dust determination threshold and the read self-position data, and outputting the generated data to the in-vehicle communication device;
A road surface condition detection device characterized by the above.

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