Scraper vehicle and towing vehicle

Abstract

Provided is a scraper vehicle which can move. In order to detect deformation of the scraper vehicle arising due to excavation, the scraper vehicle comprises: a scraper that excavates the ground when moving; and a detection device that is provided to the scraper vehicle and that detects changes in deformation caused by excavation with the scraper.　

Description

Scraper and towing vehicles

[0001] The present invention relates to a scraper vehicle and a towing vehicle with a digging scraper.

[0002] Scraper vehicles equipped with scrapers for excavating the ground have been used at civil engineering sites. These scraper vehicles have rear wheels that can be assisted by an electric motor. The scraper vehicle is towed by a tractor with an internal combustion engine, and is usually driven by the tractor's traction force, with the rear wheels assisted by the electric motor as needed.

[0003] U.S. Patent Application Publication No. 2017 / 0306589

[0004] However, Patent Document 1 does not disclose anything about distortion of the scraper vehicle caused by excavation, nor does Patent Document 1 disclose anything about control by a tractor caused by distortion of the scraper vehicle caused by excavation.

[0005] Therefore, an object of the present invention is to provide a scraper vehicle that can detect distortion of the scraper vehicle caused by excavation, and a towing vehicle that can control the scraper vehicle due to the distortion of the scraper vehicle.

[0006] The scraper vehicle of the present invention is a mobile scraper vehicle that includes a scraper that excavates the ground as it moves, and a detection device that is provided on the scraper vehicle and detects changes in distortion due to excavation by the scraper.The towing vehicle of the present invention is a towing vehicle that tows a scraper vehicle that has a scraper that excavates the ground as it moves, and includes a receiving device that is provided on the scraper vehicle and receives the detection results of the detection device that detects changes in distortion due to excavation by the scraper.

[0007] According to the scraper vehicle of the present invention, the detection device detects changes in distortion due to excavation by the scraper, thereby realizing a scraper vehicle that can detect distortion of the scraper vehicle caused by excavation. According to the towing vehicle of the present invention, the receiving device receives the detection results of the detection device that detects changes in distortion due to excavation by the scraper, thereby realizing a towing vehicle that can control the scraper vehicle due to distortion of the scraper vehicle.

[0008] Fig. 1 is a schematic diagram showing a towing vehicle and a scraper vehicle of a first embodiment; Fig. 2 is a block diagram of a main part of the scraper vehicle of the first embodiment; Fig. 3 is a diagram showing a load cell provided below the axle of the first embodiment; Fig. 4 is a flowchart executed by a control device of the scraper vehicle; Fig. 5 is a flowchart executed by a control device of the towing vehicle; Fig. 6 is a schematic diagram showing a towing vehicle and a scraper vehicle of a second embodiment;

[0009] A first embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiment described below.

[0010] (First Embodiment) Fig. 1 is a schematic diagram showing a towing vehicle 1 and a scraper vehicle 20, which are drive vehicles of this first embodiment. Fig. 2 is a block diagram of the main parts of the towing vehicle 1 and the scraper vehicle 20 of this first embodiment. The scraper vehicle 20 performs one cycle of an excavation process, a transport process, a discharge process, and a forwarding process. As shown in Fig. 1, the towing vehicle 1 tows the scraper vehicle 20 and is connected (coupled) to the scraper vehicle 20 by a hitch 21, which is a coupling device. The hitch 21 is detachable from the towing vehicle 1 and has a flexible ball joint 22 provided at one end on the towing vehicle 1 side.

[0011] (Towing Vehicle) As is clear from FIG. 1, the towing vehicle 1 of this embodiment is an autonomous type vehicle with no driver's seat. In this embodiment, the towing vehicle 1 is driven (propelled) using a fuel cell 2 instead of an internal combustion engine, and in-wheel motors 3 (see FIG. 2) provided on each of the two front wheels and four rear wheels. The in-wheel motors 3 may be provided coaxially connected to the hubs of the front and rear wheels. The towing vehicle 1 may be remotely controlled, may have a driver's seat, may use an internal combustion engine, or may be an engine powered by ammonia or hydrogen as fuel.

[0012] The towing vehicle 1 of this embodiment also has a hydrogen tank 4 that supplies hydrogen to the fuel cell 2, a storage battery 5, a GNSS 6 (Global Navigation Satellite System), a speedometer 7, a communication device 8, a memory 9, and a control device 10.

[0013] The fuel cell 2 is a power generation device that generates electricity through an electrochemical reaction between hydrogen and oxygen. The hydrogen tank 4 stores hydrogen compressed to several tens of MPa and supplies hydrogen to the fuel cell 2 via a hydrogen supply flow path (not shown). The storage battery 5 is a secondary battery that stores the electric power generated by the fuel cell 2. The storage battery 5 can supply the stored electric power to the motor 3, a storage battery 33 provided on the scraper vehicle 20, and the like. To supply electric power from the storage battery 5 to the scraper vehicle 20, the towing vehicle 1 is provided with a first connector 11 (e.g., a female connector) connected to the storage battery 5, and the scraper vehicle 20 is provided with a second connector 35 (e.g., a male connector) that engages with the first connector 11.

[0014] As shown in Figure 1, the fuel cell 2 and hydrogen tank 4 are located at the front of the towing vehicle 1. Conventionally, the internal combustion engine and driver's seat have been located at the front of the towing vehicle 1. In this embodiment, the internal combustion engine and driver's seat are omitted, allowing a large space to be provided in front of the towing vehicle 1, making it possible to place many hydrogen tanks 4 and ensuring flexibility in the placement of the fuel cell 2 and other components. Note that although the storage battery 5 is shown near the center of the towing vehicle 1 in Figure 1, it may also be located at the front of the towing vehicle 1.

[0015] The GNSS 6 uses artificial satellites to determine the position of the towing vehicle 1. The speedometer 7 detects the speed of the towing vehicle 1, and various sensors can be used, such as a vehicle speed sensor that detects the number of rotations of a shaft connected to the drive wheels, or a sensor that uses the output of the GNSS 6.

[0016] The communication device 8 is a wireless communication unit that accesses the communication device 40 described below, which is provided on the scraper vehicle 20 side, or a wide area network such as the Internet, and in this embodiment, it transmits the detection results of the speedometer 7 and various driving and control information by the control device 10 to the communication device 40.

[0017] In addition, the communication device 8 receives data resulting from calibration of the scraper vehicle 20, which will be described later, from the communication device 40.

[0018] The memory 9 is a non-volatile memory (for example, a flash memory) that stores map information of the civil engineering site, a program for automatically driving the towing vehicle 1, a program for controlling the scraper 25 (described later) and a hydraulic cylinder (not shown) (described later), etc. The memory 9 also stores data resulting from calibration of the scraper vehicle 20 received by the communication device 8.

[0019] The control device 10 is equipped with a CPU and controls the towing vehicle 1 and the scraper vehicle 20. In this embodiment, the control device 10 controls the automatic operation of the towing vehicle 1 at the civil engineering site, and controls the drive of a scraper 25 (described later) and a hydraulic cylinder (not shown) provided on the scraper vehicle 20.

[0020] The control device 10 also controls the driving and stopping of a motor 34 (described later) provided on the scraper vehicle 20. The control by the control device 10 will be described later with reference to the flowchart of FIG.

[0021] (Scraper Vehicle) In addition to the hitch 21 and ball joint 22 described above, the scraper vehicle 20 has a frame 23, a bowl 24, a scraper 25, an axle 26, wheels 27, a strain gauge 28, an accelerometer 29 (see FIG. 2), a load cell 30 (see FIG. 3), and an inclinometer 48. The scraper vehicle 20 also has an imaging device 31, a solar panel 32 which is a power generation device, a storage battery 33 which is a secondary battery, a motor 34 (see FIG. 2), a second connector 35, a third connector 36, a blade 37, and a speedometer 38 (see FIG. 2).

[0022] As shown in FIG. 2, the scraper vehicle 20 has a memory 39 that stores various data, a communication device 40, and a control device 41 that controls the entire scraper vehicle 20.

[0023] The frame 23 is a tapered metal part, and has an imaging device 31 attached to its inner surface facing the bowl 24, and a plurality of solar panels 32 attached to its outer surface. The bowl 24 has an open top and is used to store excavated material such as soil and sand excavated by the scraper 25.

[0024] The scraper 25 is a blade- or spatula-shaped member for scraping away soil and sand from a travel surface such as the ground, and in this embodiment, is provided integrally with the bottom of the bowl 24. Because the bowl 24 and the scraper 25 are provided integrally, the scraper 25 can dig into the ground and excavate soil and sand by tilting the bowl 24 toward the ground using a hydraulic cylinder (not shown). The bowl 24 is also provided with an opening (not shown), and when the bowl 24 is tilted toward the ground, the material excavated by the scraper 25 is received into the bowl 24 through the opening (not shown).

[0025] When excavation by the scraper 25 is completed, the bowl 24 is tilted toward the ground by a hydraulic cylinder (not shown), so that the scraper 25 is lifted off the ground. When the scraper 25 is lifted off the ground, the load of the excavated material stored in the bowl 24 acts on the ball joint 22 and the pillow block 42 (see FIG. 3 ), which will be described later and which bears the load of the axle 26.

[0026] The axle 26 rotates due to the tractive force of the towing vehicle 1, and the wheels 27 are connected to both ends of the axle 26 and are a pair of driven wheels that rotate as the axle rotates. The wheels 27 may be provided at the front and rear of the scraper vehicle 20 as front and rear wheels.

[0027] The strain gauge 28 is a metal resistor, and is attached, for example, via an electrical insulator, to the lower side of the hitch 21, which is the object to be measured. The strain gauge 28 measures strain by changing the resistance value as the metal expands and contracts in proportion to the force applied to the hitch 21. The strain detected by the strain gauge 28 includes strain caused by the material excavated by the scraper 25 being placed in the bowl 24, and strain caused when the scraper 25 digs into the ground and excavates.

[0028] When the material excavated by the scraper 25 is placed in the bowl 24, the load of the excavated material is applied to the bowl 24. The load of the bowl 24 is applied separately to the flexible ball joint 22 and the wheels 27. Because part of the load of the bowl 24 is supported by the flexible ball joint 22, a tensile stress acts below the hitch 21. The strain gauge 28 measures the change in resistance value caused by the tensile stress of the hitch 21, and the control device 41 can measure the weight of the material excavated in the bowl 24 from the resistance value detected by the strain gauge 28.

[0029] When detecting only the strain caused by the material excavated by the scraper 25 being placed in the bowl 24, it is preferable to keep the scraper 25 away from the ground. For this reason, it is preferable to perform calibration by changing the loading state of the bowl 24 with the scraper 25 away from the ground and performing measurements using the strain gauges 28. In this case, calibration may be performed in a stationary state where the scraper vehicle 20 is stationary, or in a moving state where the scraper vehicle 20 is towed by the towing vehicle 1, or in both a stationary and moving state.

[0030] It is preferable that calibration during movement be corrected according to the attitude of the scraper vehicle 20. This is because compressive stress acts on the hitch 21 when the ground is downwardly inclined, whereas tensile stress acts on the hitch 21 when the ground is upwardly inclined. The inclination of the scraper vehicle 20 relative to the ground can be detected by an inclinometer 48 provided on the underside of the frame 23. The inclinometer 48 may also be provided on the upper surface of the frame 23.

[0031] On the other hand, the strain caused by the digging force when the scraper 25 digs into the ground can be calibrated from the difference between the measurement of the strain gauge 28 when the scraper 25 is digging into the ground a predetermined amount while in a moving state and the measurement of the strain gauge 28 when the scraper 25 is away from the ground.

[0032] It is desirable to calibrate the distortion caused by the scraper 25 digging into the ground while changing the amount of penetration of the scraper 25 into the ground. For example, the amount of penetration of the scraper 25 into the ground can be set in a program for automatically driving the towing vehicle 1. For example, the number of stages, such as one or two, can be set, or the drive amount of the scraper 25 can be set to 10 mm, 20 mm, or 30 mm. Furthermore, the calibration of the distortion caused by the scraper 25 digging into the ground can be performed under different loading conditions by varying the loading state of the bowl 24. It is preferable to correct the calibration of the distortion caused by the scraper 25 digging into the ground according to the attitude of the scraper vehicle 20.

[0033] In the first embodiment, it is detected in advance how the load W applied to bowl 24 is divided between ball joint 22 and pillow block 42. As an example, assume that 40% of the load W acts on ball joint 22 and 60% of the load W acts on pillow block 42. In this case, control device 41 can calculate the load W applied to bowl 24 by converting the resistance value measured by strain gauge 28, which is 40% of the load W, to 100%.

[0034] In this embodiment, the resistance values ​​of the strain gauges 28 may be measured when the bowl 24 is empty or when a load of 100 kg is applied to the bowl 24, and may be stored as a table in the memory 39. When the bowl 24 is empty, only the load of the scraper vehicle 20 acts on the bowl 24, and the amount of change from this state represents the weight of the excavated material contained in the bowl 24.

[0035] The table stored in the memory 39 may also store resistance values ​​of the strain gauges 28 when multiple loads (e.g., 200 kg, 300 kg) are applied to the bowl 24. Although one strain gauge 28 is shown in FIG. 1, multiple strain gauges may be used, and the number is not limited. Since the amount of strain is greatest at the center of the hitch 21 in the X direction, which is the left-right direction, it is preferable to provide the strain gauge 28 at the center of the hitch 21 in the left-right direction and below the hitch 21 in the Z direction, which is the up-down direction.

[0036] In this embodiment, the accelerometer 29 detects acceleration acting on the scraper vehicle 20, and any type of accelerometer can be used, such as mechanical, optical, or semiconductor. In this embodiment, the accelerometer 29 detects acceleration in the Z-axis direction near the strain gauge 28, but this is not limited to this, and the accelerometer 29 may also detect acceleration in the X-axis direction or the Y-axis direction. Furthermore, the number of accelerometers 29 may be one, or at least one accelerometer may be provided at each of multiple locations on the scraper vehicle 20. In this case, the accelerometer 29 may be provided near the load cell 30, or may be provided on the towing vehicle 1. If the accelerometer 29 is provided on the towing vehicle 1, it is preferable to provide it near the ball joint 22.

[0037] In this embodiment, the control device 41 calculates the amount of excavated material, such as soil and sand, stored in the bowl 24 based on the strain detected by the strain gauges 28 when the output of the accelerometer 29 is smaller than the threshold value. Alternatively, the control device 41 may calculate the amount of excavated material, such as soil and sand, stored in the bowl 24 from the outputs of N strain gauges 28 (N is a natural number) that have the smallest output from the accelerometer 29, or may perform a calculation to weight the output of the strain gauges 28 when the output of the accelerometer 29 is small. In this first embodiment, if a correction value for the output of the strain gauges 28 corresponding to the output of the accelerometer 29 is stored in the memory 39, the control device 41 can correct the output of the strain gauges 28 using the correction value stored in the memory 39. In this way, the control device 41 processes or selects the detection results of the strain gauges 28 using the output of the accelerometer 29.

[0038] FIG. 3 is a diagram showing the load cell 30 provided below the axle 26 of this embodiment. As shown in FIG. 3, the axle 26 is rotatably supported by a bearing 43, which is held by a pillow block 42 that serves as a bearing stand. The load cell 30 is provided below the pillow block 42 so as to detect the load of the material excavated in the bowl 24 acting on the wheel 27. Various types of load cells 30, such as a piezoelectric load cell or a strain load cell, can be used. Although two load cells 30 are shown in FIG. 3, the number of load cells 30 may be one, or three or more.

[0039] In this embodiment, as described above, the measurement values ​​of the load cell 30 when the bowl 24 is empty and when a load of 100 kg is applied to the bowl 24 may be stored as a table in the memory 39. In this case, it is desirable to store the resistance values ​​of the load cell 30 at multiple loads (e.g., 200 kg, 300 kg). By performing calibration by measuring with the strain gauges 28 and the load cell 30 while changing the load state of the bowl 24, the ratio of the load applied to the ball joint 22 to the load applied to the pillow block 42 can be calculated, and this ratio is stored in the memory 39. Note that this calibration is preferably performed while the towing vehicle 1 and the scraper vehicle 20 are stationary, but it may also be performed while the scraper vehicle 20 is being towed by the towing vehicle 1, or while stationary and towed.

[0040] Calibration may be performed only once or periodically, or may be performed when the wheels 27 are replaced or after the air pressure of the wheels 27 is adjusted. Calibration may also be performed when the wheels of the towing vehicle 1 are replaced or after the air pressure of the wheels is adjusted. The second and subsequent calibrations may be performed only when the bowl 24 is empty, or may be performed with a load of 100 kg, with fewer measurement items or fewer measurements than the first calibration.

[0041] In addition to being used during the aforementioned calibration, load measurement by the load cell 30 may also be performed when the material excavated by the scraper 25 is placed in the bowl 24. In this case, too, the amount of excavated material, such as soil and sand, placed in the bowl 24 is calculated based on the load detected by the load cell 30 when the output of the accelerometer 29 is smaller than the threshold value. Alternatively, the control device 41 may calculate the amount of excavated material, such as soil and sand, placed in the bowl 24 from the outputs of N load cells 30 with small accelerometer 29 outputs (N is a natural number), or may perform a calculation to weight the outputs of the load cells 30 when the output of the accelerometer 29 is small. In this way, the control device 41 processes or selects the detection results of the load cells 30 using the outputs of the accelerometer 29.

[0042] The imaging device 31 is a digital camera that has a lens, an imaging element, an image processing engine, etc., and captures moving and still images. In this embodiment, the imaging device 31 is used to capture an image of the excavated material stored in the bowl 24 and detect whether the bowl 24 is full. Note that instead of the imaging device 31, a non-contact range finder such as an ultrasonic range finder or a laser range finder may be provided on the frame 23 to detect whether the bowl 24 is full. The control device 41 may start measurement using the strain gauge 28, the accelerometer 29, etc., when the bowl 24 is full.

[0043] The solar panel 32 is a power generation device and is mounted on the frame 23. The side surfaces of the frame 23 are tapered so that the side surfaces of the frame 23 can more easily receive sunlight. Incidentally, if a tilting mechanism is provided on the upper surface of the frame 23, the solar panel 32 mounted on the upper surface of the frame 23 can more easily receive sunlight. Incidentally, the solar panel 32 may be mounted on the towing vehicle 1, and the power generated by the solar panel 32 may be stored in the storage battery 5. Furthermore, the power generated by the solar panel 32 may be used as an auxiliary power source for driving the fuel cell 2.

[0044] The storage battery 33 stores the power generated by the fuel cell 2 via the second connector 35, and stores the power generated by the solar panel 32. The power stored in the storage battery 33 is used to drive the motor 34 that directly drives the wheels 27. The storage battery 33 is preferably provided in front of the scraper vehicle 20 (-X direction), and in this embodiment, it is provided in the hitch 21.

[0045] The motor 34 is an in-wheel motor that is installed inside the wheel 27 or is coaxially connected to the hub of the wheel 27. When the scraper 25 scrapes a large amount of ground surface, the scraper 25 gets stuck in the ground surface, increasing running resistance. In this case, the drive wheels of the towing vehicle 1 may spin, and the scraper vehicle 20 may not be able to be towed by the towing force of the towing vehicle 1 alone, requiring the use of a pusher.

[0046] Therefore, in this embodiment, when it is difficult to tow the scraper vehicle 20 using the towing vehicle 1 alone, the wheels 27 are driven by the motor 34. Driving the wheels 27 with the motor 34 eliminates the need for a pusher and the effort of connecting the pusher to the scraper vehicle 20, thereby shortening the construction period. In this way, the motor 34 functions as an auxiliary drive device. In this embodiment, the towing vehicle 1 and the motor 34 are driven by power generated by a fuel cell, which reduces emissions of greenhouse gases such as carbon dioxide. Note that power generated by solar panels 32 may be used instead of or in addition to the fuel cell.

[0047] The second connector 35 engages with the first connector 11 to supply the power stored in the storage battery 5 to the storage battery 33. The third connector 36 is a connector for supplying the power stored in the storage battery 33 to a second scraper car 20 when the second scraper car 20 is connected behind the scraper car 20.

[0048] The blade 37 is a metal mechanical part that discharges the excavated material stored in the bowl 24 at the discharge site during the discharge process. The blade 37 is positioned in the +X direction except during the discharge process, and is moved in the -X direction by a hydraulic cylinder (not shown) during the discharge process to discharge the excavated material. The forwarding process that follows the discharge process is a process in which the scraper vehicle 20 moves from the discharge site to the excavation site.

[0049] The speedometer 38 detects the speed of the scraper vehicle 20, and various sensors can be applied, such as a vehicle speed sensor that detects the number of rotations of the axle 26, or a sensor that uses the output of a GNSS (not shown) to determine the position of the scraper vehicle 20. The speedometer 38 may be omitted.

[0050] Any type of memory may be used for the memory 39, and in this embodiment, a non-volatile semiconductor memory (e.g., flash memory) is used. The memory 39 stores various programs for driving the scraper vehicle 20, measurement results obtained by the strain gauges 28, accelerometers 29, and load cells 30, and calculation results calculated by the control device 41. The memory 39 also stores various data obtained during the calibration described above.

[0051] The communication device 40 communicates with the communication device of the base station, the communication device provided at the dumping site during the discharge process, and the communication device 8 on the towing vehicle 1 side. The communication device 40 can use any communication method, but in this embodiment, it wirelessly communicates data related to the weight of the bowl 24 using a wireless LAN such as Wi-Fi (registered trademark). Note that if an accelerometer is provided on the towing vehicle 1, the communication device 8 on the towing vehicle 1 side may communicate the acceleration detected by the accelerometer to the communication device 40.

[0052] The control device 41 is equipped with a CPU (Central Processing Unit) and controls the entire scraper vehicle 20. In this embodiment, it controls the weight measurement of the excavated material contained in the bowl 24 and the auxiliary drive by the motor 34.

[0053] The control of the towing vehicle 1 and scraper vehicle 20 configured as described above will be explained using the flowcharts of Figures 4 and 5. Figure 4 is a flowchart executed by the control device 41 of the scraper vehicle 20, and Figure 5 is a flowchart executed by the control device 10 of the towing vehicle 1.

[0054] (Explanation of Flowchart) The control device 41 performs strain measurement while the scraper vehicle 20 is stationary (step S1). The control device 41 stores in the memory 39 the resistance values ​​of the strain gauges 28 when the scraper 25 is separated from the ground and a plurality of known loads (e.g., 200 kg, 300 kg) are applied to the bowl 24.

[0055] The strain measurement in step S1 may be performed anywhere, such as a test field, a factory, or a warehouse, not limited to a civil engineering site. The strain measurement in step S1 may be performed on flat ground or on sloping ground. It is desirable to correct the strain acting on the strain gauge 28 due to the slope based on the output of the inclinometer 48 when performing the strain measurement in step S1 on sloping ground. For example, the control device 41 may correct the results of the strain measurement performed on sloping ground based on the results of the strain measurement performed on flat ground, and store the corrected results in the memory 39 together with the slope angle.

[0056] The control device 41 performs strain measurements while the scraper vehicle 20 is moving in a test field, a civil engineering site, etc. (Step S2). The control device 41 stores in the memory 39 the resistance values ​​of the strain gauges 28 when a plurality of known loads (e.g., 200 kg, 300 kg) are applied to the bowl 24 in both a state where the scraper 25 is off the ground and a state where the scraper 25 is digging into the ground.

[0057] It is desirable to measure the strain in step S2 while changing the amount of penetration of the scraper 25 into the ground. It is also desirable to correct the strain acting on the strain gauge 28 due to the tilt based on the output of the inclinometer 48 during the strain measurement in step S2.

[0058] Strain measurement while moving may cause changes in the measurement results of the strain gauges 28 depending on the soil properties at the test field or civil engineering site. For this reason, soil properties such as the soil moisture content and cone index may be measured, and the strain measurement results may be stored in memory 39 along with the soil properties. The moisture content may be detected using, for example, a near-infrared moisture meter, a microwave oven, or a weighing scale. The cone index may be detected using, for example, a cone penetrometer. Furthermore, the soil hardness may be classified into several levels (e.g., 3 to 5 levels) based on the measured soil properties, and the strain acting on the strain gauges 28 may be corrected based on the soil hardness.

[0059] The control device 41 determines whether strain measurement while the scraper vehicle 20 is moving, i.e., whether dynamic strain measurement, has been completed (step S3). If dynamic strain measurement has not been completed, the control device 41 repeats step S2, and if dynamic strain measurement has been completed, the control device 41 proceeds to step S4. Here, it is assumed that dynamic strain measurement has been completed, and the control device 41 proceeds to step S4.

[0060] The control device 41 calculates the strain associated with excavation from the difference between the measurement of the strain gauges 28 when the scraper 25 is digging into the ground a predetermined amount while the scraper 25 is moving and the measurement of the strain gauges 28 when the scraper 25 is released from the ground (step S4). The control device 41 may also calculate the strain from the difference in the average values ​​of the measurement results in each state. Furthermore, the control device 41 may calculate the difference in the average values ​​when the scraper vehicle 20 is moving uphill, when the scraper vehicle 20 is moving downhill, and when the scraper vehicle 20 is moving on flat ground, based on the measurement results of the inclinometer 48. These calculation results are stored in the memory 39.

[0061] In the flowchart of Fig. 4, the measurement of strain in a stationary state may be omitted if past data can be applied. Furthermore, the measurement of strain in a moving state may be performed prior to the measurement of strain in a stationary state.

[0062] Next, a description will be given of the flowchart of Fig. 5 executed by the control device 10 of the towing vehicle 1. In the first embodiment, the flowchart of Fig. 5 is started before the excavation process at the excavation site begins.

[0063] The control device 10 receives data stored in the memory 39 through communication between the communication device 8 and the communication device 40 of the scraper vehicle 20 (step S101). In the first embodiment, the control device 10 receives the data related to the calibration described in the flowchart of Fig. 4 and stores it in the memory 9. Note that if the data related to the calibration of the scraper vehicle 20 to be towed has already been stored in the memory 9, the control device 10 omits step S101.

[0064] The control device 10 starts moving the scraper vehicle 20 while towing it, and controls the hydraulic cylinder (not shown) to dig the scraper 25 into the ground and start excavation (step S102). Here, the control device 10 starts excavation based on a program for automatically driving the towing vehicle 1 and a program for controlling the hydraulic cylinder (not shown).

[0065] The control device 10 acquires various data during excavation and stores it in the memory 9 (step S103). The control device 10 acquires the detection results (measurement results) of the strain gauges 28, accelerometers 29, load cells 30, and speedometers 38 through communication between the communication device 8 and the communication device 40 of the scraper vehicle 20, and stores them in the memory 9. The control device 10 also receives image data from the imaging device 31 and stores it in the memory 9. Note that when the control device 10 uses the detection results of the speedometer 7, it may omit receiving the detection results of the speedometer 38. The control device 10 may also acquire the detection results of the inclinometer 48.

[0066] The control device 10 determines whether to change the excavation conditions based on the various data acquired in step S103 (step S104). The control device 10 determines whether to change the excavation conditions based on the amount of penetration of the scraper 25, the running resistance caused by the weight of the excavated material loaded in the bowl 24, the moving speed, the amount of excavation so far, etc. In this example, it is assumed that the actual amount of excavation is less than the planned amount of excavation, so the excavation conditions are changed and the process proceeds to step S105.

[0067] The control device 10 changes the excavation conditions to increase the excavation amount (step S105). Specifically, the control device 10 increases the amount of penetration of the scraper 25 into the ground. Note that, instead of or in addition to this, the control device 10 may reduce the travel speed of the towing vehicle 1.

[0068] The control device 10 determines whether auxiliary drive is necessary (step S106). Here, the control device 10 determines that auxiliary drive is necessary because the running resistance increases due to an increase in the amount of penetration of the scraper 25 or an increase in the weight of the excavated material loaded in the bowl 24, and proceeds to step S107. If the control device 10 determines that auxiliary drive is unnecessary, the control device 10 proceeds to step S108. In step S106, the control device 10 may also consider, as factors in its determination, whether the running resistance increases because the road along which the vehicle will travel is uphill, or whether the running resistance decreases because the road along which the vehicle will travel is downhill. The control device 10 may also consider, as factors in its determination, the running resistance caused by the hardness of the road along which the vehicle will travel.

[0069] The control device 10 instructs the control device 41 of the scraper vehicle 20 to perform auxiliary driving (step S107). The control device 41 applies driving force to the rear wheels using the motor 34, which is an auxiliary driving device. In this way, in the first embodiment, the control device 10 can prevent the towing vehicle 1 from stopping. Note that the control device 10 may make the determination in step S106 before step S104, or may make the determination in step S106 before or after step S104.

[0070] The control device 10 determines whether the excavation amount has reached a predetermined amount (for example, whether the bowl 24 is fully loaded) (step S108). The control device 10 determines whether the excavation amount has reached the predetermined amount based on at least one of the detection results of the strain gauges 28, the detection results of the load cells 30, and the image data captured by the imaging device 31.

[0071] If the excavation amount has not reached the predetermined amount, the control device 10 repeats step S103 and subsequent steps. If the excavation amount has reached the predetermined amount, the control device 10 ends this flowchart and performs a transport process to move the excavated material to a discharge position where it will be discharged. When the excavation amount has reached the predetermined amount, the control device 10 or 41 may calculate the load amount (e.g., how many tons) from the detection results of the strain gauge 28, for example, and store the calculated load amount in memory 9 or memory 39. Note that the control device 10 moves the scraper 25 to a position away from the ground when not in the excavation process. Here, the control device 10 ends this flowchart when the excavation amount has reached the predetermined amount.

[0072] 5 may be performed by a worker at a remote location or by a central control device located at a remote location. This central control device may acquire various data from the communication device 40, make various decisions, and transmit the results of these decisions to the control device 10 or the control device 41.

[0073] The central control device may be configured to control multiple towing vehicles 1, in which case it may acquire the excavation conditions of the master towing vehicle 1 and transmit the acquired excavation conditions and auxiliary drive conditions for the motor 34 to the other towing vehicles 1. Alternatively, the master towing vehicle 1 may transmit the excavation conditions to the other towing vehicles 1.

[0074] As described above, according to the first embodiment, the amount of drive of the scraper 25 into the ground, i.e., the amount of penetration, is controlled based on the detection results of the strain gauge 28, and the auxiliary drive by the motor 34 is controlled, thereby realizing an automated towing vehicle 1 and scraper vehicle 20.

[0075] Second Embodiment A second embodiment will be described below using Fig. 6. The same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted or simplified. The scraper car 20 according to the second embodiment is a train-type car in which a first scraper car 20a and a second scraper car 20b, which is the last car, are connected (coupled). The train-type scraper car 20 may include three or more cars.

[0076] In this second embodiment, the first scraper car 20a and the second scraper car 20b have the same configuration, so the configuration of the first car is given the symbol a and the configuration of the second car is given the symbol b.

[0077] When performing calibration related to the strain gauges 28b, it is desirable to couple the first scraper car 20a and the second scraper car 20b and load the bowl 24a of the first car with a full load of excavated material or with an object of equivalent weight. Note that calibration related to the strain gauges 28b may be performed with the bowl 24a empty or with any known heavy object loaded.

[0078] As described above, according to the second embodiment, the amount of drive of the scraper 25b into the ground, i.e., the amount of penetration, is controlled based on the detection results of the strain gauge 28b, and the auxiliary drive by the motor 34b is controlled, thereby realizing an automated towing vehicle 1 and scraper vehicle 20b.

[0079] The embodiment described above is merely an example for explaining the present invention, and various modifications can be made without departing from the scope of the present invention. For example, in the above embodiment, the towing vehicle 1 is used as the driving vehicle, but a push-type driving vehicle that pushes the scraper vehicle 20 from behind may also be used.

[0080] In the above embodiment, the strain gauge 28 is provided on the hitch 21, but the strain gauge 28 may be provided at a location where a tensile stress is generated by a load.

[0081] Furthermore, the scraper vehicle 20 may be provided with a gyro sensor that detects angular velocity from the Coriolis force, and when the angular velocity acting on the scraper vehicle 20 is small, measurements may be performed using the strain gauge 28, accelerometer 29, or load cell 30. Furthermore, a gyro sensor may be used instead of or in combination with the acceleration sensor.

[0082] In the above embodiment, the control device 10 on the towing vehicle 1 side controls the drive of the motor 34. Alternatively, the control device 41 on the scraper vehicle 20 side may control the drive of the motor 34. In this case, it is preferable that the control device 41 acquires data related to the movement state of the towing vehicle 1, such as the detection results of the speedometer 7 from the towing vehicle 1 and the state of a shift lever (not shown).

[0083] REFERENCE SIGNS LIST 1 towing vehicle 2 fuel cell 3 motor 4 hydrogen tank 7 speedometer 10 control device 20 scraper vehicle 21 hitch 22 ball joint 24 bowl 25 scraper 28 strain gauge 29 accelerometer 30 load cell 39 memory 40 communication device 41 control device 48 inclinometer

Claims

1. A movable scraper vehicle, comprising: a scraper for excavating the ground during movement; a detection device provided on the scraper vehicle for detecting a change in distortion occurring in the scraper vehicle in response to a change in the amount of penetration into the ground when excavating by the scraper; a first communication device for transmitting the change in distortion detected by the detection device; and a scraper vehicle equipped with the first communication device.

2. A bowl capable of accommodating the excavated material excavated by the scraper, wherein the detection device changes the load on the bowl to detect a change in the distortion caused by the excavation of the scraper. The scraper vehicle according to claim 1.

3. The scraper vehicle has a first scraper vehicle and a second scraper vehicle connected to the first scraper vehicle, wherein the detection device has a first detection device provided on the first scraper vehicle and a second detection device provided on the second scraper vehicle. The scraper vehicle according to claim 1.

4. A first control device for controlling the amount of penetration of the scraper into the ground according to an instruction transmitted from a towing vehicle that tows the scraper vehicle based on the change in distortion detected by the detection device. The scraper vehicle according to any one of claims 1 to 3.

5. A property detection device for detecting the property of the excavated material excavated by the scraper, wherein the first control device corrects the distortion acting on the detection device based on the property detected by the property detection device. The scraper vehicle according to claim 4.

6. The first communication device communicates the change in distortion detected by the detection device to the towing vehicle. The scraper vehicle according to claim 4.

7. An inclinometer for measuring the inclination of the scraper vehicle or the inclination of the ground, wherein the first control device corrects the distortion acting on the detection device based on the measurement result of the inclinometer, and the first communication device communicates the corrected distortion to the towing vehicle. The scraper vehicle according to claim 6.

8. The first control device receives the instruction transmitted from the towing vehicle via the first communication device and controls the scraper vehicle. The scraper vehicle according to claim 6.

9. The scraper vehicle according to claim 4, wherein the first control device controls the amount of penetration of the scraper into the ground based on the excavation conditions changed according to the instruction transmitted from the towing vehicle based on the change in the distortion detected by the detection device.

10. A towing vehicle that tows a scraper vehicle having a scraper that excavates the ground during movement, a receiving device that receives the detection result of a detection device provided in the scraper vehicle that detects a change in distortion generated in the scraper vehicle in response to a change in the amount of penetration into the ground when excavating by the scraper; a second communication device that transmits the amount of penetration of the scraper into the ground based on the change in the distortion included in the detection result received by the receiving device. The towing vehicle is provided.

11. The towing vehicle according to claim 10, further comprising a second control device that controls the amount of penetration of the scraper into the ground based on the change in the distortion included in the detection result received by the receiving device.

12. The towing vehicle according to claim 11, wherein the second control device changes the excavation conditions for controlling the amount of penetration of the scraper into the ground based on the change in the distortion included in the detection result received by the receiving device.

13. The scraper vehicle includes a driving device provided in the scraper vehicle and capable of driving the scraper vehicle, The towing vehicle according to claim 11 or claim 12, wherein the second control device controls the driving device based on the change in the distortion included in the detection result received by the receiving device.