Load capacity estimation system for special-purpose vehicles, load capacity estimation method for special-purpose vehicles, and computer program

Abstract

To provide a system and a method for estimating the load of a specially-equipped vehicle and a computer program.SOLUTION: A specially-equipped vehicle having a hydraulic actuator for lifting a cargo box includes: a first acquisition unit for acquiring first data on the magnitude of a hydraulic pressure on the basis of output from a pressure meter for measuring the magnitude of a hydraulic pressure that acts on the hydraulic actuator; a second acquisition unit for acquiring second data regarding an inclined angle on the basis of output from an inclination meter for measuring the inclination angle of the specifically-equipped vehicle; a storage unit for storing the relation among the first data, the second data, and data including the weight of the load in the cargo box; and an estimation unit for estimating the weight of the load in the cargo box with reference to the relation among the data stored in the storage unit if the first data and the second data are acquired.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a loading weight estimation system for a special vehicle, a method for estimating the loading weight of a special vehicle, and a computer program.

Background Art

[0002] In recent years, in large vehicles such as trucks, those equipped with a loading weight meter for measuring the weight of the loaded goods (loading weight) are known.

[0003] Conventional loading weight meters use load sensors attached to both ends of the front and rear axles to measure the loads applied to each tire in the front, rear, left, and right directions, and obtain the loading weight from the sum of the outputs of each load sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in conventional loading weight meters, since the method of converting the sum of the outputs of each load sensor into the loading weight is adopted, when the vehicle is on a sloping ground or when the balance of the loaded goods on the loading platform is not even, it may not be possible to measure the correct loading weight.

[0006] An object of the present invention is to provide a loading weight estimation system for a special vehicle, a method for estimating the loading weight of a special vehicle, and a computer program that can accurately estimate the loading weight even when the vehicle is on a sloping ground.

Means for Solving the Problems

[0007] A load weight estimation system for a special-purpose vehicle according to one aspect of the present invention includes: a first acquisition unit that acquires first data relating to the magnitude of hydraulic pressure based on the output from a pressure gauge that measures the magnitude of hydraulic pressure acting on a hydraulic actuator for raising and lowering a cargo box in a special-purpose vehicle equipped with a hydraulic actuator; a second acquisition unit that acquires second data relating to the inclination angle based on the output from an inclinometer that measures the inclination angle of the special-purpose vehicle; a storage unit that stores the relationship between the first data, the second data, and data including the load weight in the cargo box; and an estimation unit that, when the first data and the second data have been acquired, estimates the load weight in the cargo box by referring to the relationship between the data stored in the storage unit.

[0008] A method for estimating the load weight of a special-purpose vehicle according to one aspect of the present invention involves a special-purpose vehicle equipped with a hydraulic actuator for raising and lowering a cargo box. The method involves acquiring first data relating to the magnitude of the hydraulic pressure acting on the hydraulic actuator based on the output of a pressure gauge that measures the magnitude of the hydraulic pressure acting on the hydraulic actuator, acquiring second data relating to the inclination angle based on the output of an inclinometer that measures the inclination angle of the special-purpose vehicle, and then using a computer to perform a process of estimating the load weight in the cargo box by referring to the relationship between the first data, the second data, and data including the load weight in the cargo box.

[0009] A computer program according to one aspect of the present invention causes a computer to acquire first data relating to the magnitude of hydraulic pressure acting on a hydraulic actuator in a special-purpose vehicle equipped with a hydraulic actuator for raising and lowering a cargo box, based on the output of a pressure gauge that measures the magnitude of hydraulic pressure acting on the hydraulic actuator, acquire second data relating to the inclination angle based on the output of an inclinometer that measures the inclination angle of the special-purpose vehicle, and execute a process to estimate the load weight in the cargo box by referring to the relationship between the first data, the second data, and data including the load weight in the cargo box. [Effects of the Invention]

[0010] According to this invention, the load weight can be estimated with high accuracy even when the vehicle is located on an inclined surface. [Brief explanation of the drawing]

[0011] [Figure 1] This is a side view showing the overall configuration of a special-purpose vehicle according to Embodiment 1. [Figure 2] This is a plan view showing the overall configuration of the special-purpose vehicle according to Embodiment 1. [Figure 3] This is a side view of the cargo box in an upright position. [Figure 4] This is a block diagram illustrating the configuration of the load weight estimation system. [Figure 5] This is a conceptual diagram showing an example of the configuration of the relational table in Embodiment 1. [Figure 6] This is an explanatory diagram illustrating how to calculate the load weight given input values. [Figure 7] This flowchart explains the procedure for estimating load weight using a relationship table. [Figure 8] This is a schematic diagram showing an example of how load weight is displayed. [Figure 9] This is a conceptual diagram showing an example of the configuration of the relationship table in Embodiment 2. [Figure 10] This is a block diagram illustrating the configuration of the load weight estimation system in Embodiment 3. [Figure 11] This is a flowchart illustrating the procedure for estimating the load weight in Embodiment 3. [Figure 12] This is a block diagram illustrating the configuration of the load weight estimation system in Embodiment 4. [Figure 13] This is a flowchart illustrating the procedure for estimating the load weight in Embodiment 4. [Figure 14] This is a block diagram illustrating the configuration of the load weight estimation system in Embodiment 5. [Figure 15] This is a flowchart illustrating the procedure for estimating the load weight in Embodiment 5. [Figure 16] This is a flowchart illustrating the procedure for estimating the load weight in Embodiment 6. [Figure 17]It is a block diagram for explaining the configuration of the server device in Embodiment 7. [Figure 18] It is a schematic diagram for explaining a configuration example of a learning model. [Figure 19] It is a conceptual diagram of training data. [Figure 20] It is a flowchart for explaining the first generation method of a learning model. [Figure 21] It is a flowchart for explaining the second generation method of a learning model.

Mode for Carrying Out the Invention

[0012] Hereinafter, the present invention will be specifically described based on the drawings showing its embodiments. (Embodiment 1) FIG. 1 is a side view showing the overall configuration of the special vehicle 1 according to Embodiment 1, FIG. 2 is a plan view thereof, and FIG. 3 is a side view in a state where the cargo box is erected. The special vehicle 1 illustrated in FIGS. 1 to 3 is a dump truck including a truck chassis 2 as a traveling part and a dump device 3 which is an example of a mounting device mounted on the traveling part. In the following description, the front-rear, left-right, and up-down directions represent the front-rear, left-right, and up-down directions as seen from the driver sitting in the driver's seat of the truck chassis 2. Note that in FIG. 2, for the sake of explanation, a state where the dump device 3 is removed is shown.

[0013] The truck chassis 2 comprises a cab 20 in which a driver's seat is provided, and a chassis frame 21 that supports the cab 20. The chassis frame 21 is composed of a pair of left and right main frames (longitudinal joists) 21A, 21A extending in the longitudinal direction, and a plurality of cross members (transverse joists) 21B, ..., 21B connecting the pair of left and right main frames 21A, 21A (see Figure 2). The front wheels 22F and rear wheels 22R, 22R of the truck chassis 2 are rotatably mounted to the main frames 21A, 21A via a suspension system not shown. The truck chassis 2 comprises an engine 70 (prime mover) and a transmission connected to the engine 70 via a clutch, and is configured to run by transmitting the driving force of the engine 70 to the drive system of the drive wheels (e.g., the front wheels 22F) via the transmission.

[0014] The dumping device 3 comprises a subframe 30 fixed to the chassis frame 21, and a cargo box 4 supported by the subframe 30, on which cargo such as soil and sand is loaded. The cargo box 4 is rotatably supported around a hinge shaft 31 extending in the left-right direction at the rear end of the subframe 30. The cargo box 4 is an open-topped box and comprises a front panel 41, a pair of left and right side panels 42, and a rear panel (rear tailgate) 43 arranged to surround a rectangular bottom 40. The rear panel 43 is configured to be openable and closable.

[0015] The dumping device 3 is equipped with a hoist mechanism 5 for tilting the cargo box 4. The hoist mechanism 5 includes, for example, a lift arm 51, a hydraulic cylinder 52, and a tension link 53. When the hydraulic cylinder 52 of the hoist mechanism 5 is extended, the front of the cargo box 4 is lifted and rotates in a direction that increases the tilt angle. In this embodiment, the rotation of the cargo box 4 in a direction that increases the tilt angle is also called the raising of the cargo box 4. On the other hand, when the hydraulic cylinder 52 of the hoist mechanism 5 is shortened, the front of the cargo box 4 is lowered and rotates in a direction that decreases the tilt angle. In this embodiment, the rotation of the cargo box 4 in a direction that decreases the tilt angle is also called the lowering of the cargo box 4.

[0016] The hydraulic mechanism for extending and retracting the hydraulic cylinder 52 includes a hydraulic pump 61, a hydraulic oil tank 62, a control valve 63, and the like. The hydraulic pump 61, which is the hydraulic power source, is driven by the power of the engine 70 transmitted via a PTO 71 (Power Take-Off), which pumps hydraulic oil from the hydraulic oil tank 62 through the hydraulic piping 64 and supplies hydraulic oil (pressurized oil) to the hydraulic cylinder 52 through the main pipe 65 connected to the discharge port. The connection and disconnection of the power transmission from the engine 70 is switched by a PTO switch 72 located inside the cab 20.

[0017] The direction of supply of hydraulic fluid discharged from the hydraulic pump 61 is switched by a control valve 63 operated by a manual operating lever 67. For example, when the control valve 63 is in the neutral position by operating the operating lever 67, no hydraulic fluid is supplied from the hydraulic pump 61 to the hydraulic cylinder 52, and the cargo box 4 does not tilt. When the operating lever 67 is operated to the raised position, the control valve 63 is switched, and hydraulic fluid (pressurized oil) is supplied from the hydraulic pump 61 to the hydraulic cylinder 52. The hydraulic cylinder 52 extends as hydraulic fluid is supplied, raising the cargo box 4. On the other hand, when the operating lever 67 is operated to the lowered position, the control valve 63 is switched, and the hydraulic fluid supplied to the hydraulic cylinder 52 is returned to the hydraulic fluid tank 62. Consequently, the hydraulic cylinder 52 shortens, lowering the cargo box 4.

[0018] The hydraulic mechanism is equipped with a pressure gauge 81 for measuring the magnitude of the hydraulic pressure acting on the hydraulic cylinder 52. The special vehicle 1 is also equipped with an inclinometer 82 for measuring the inclination (pitch and roll) of the truck chassis 2 and an inclinometer 83 for measuring the inclination (pitch and roll) of the cargo box 4.

[0019] The pressure gauge 81 measures the cylinder pressure (hydraulic pressure) of the hydraulic cylinder 52 over time and outputs measurement data related to the measured cylinder pressure. The inclinometer 82 is attached to an appropriate location on the chassis frame 21 (for example, near the center in the front-rear and left-right directions). The inclinometer 82 measures the front-rear inclination (pitch) and left-right inclination (roll) of the truck chassis 2 over time with respect to gravity (vertical direction) and outputs measurement data related to the measured inclination. The inclinometer 83 is attached to an appropriate location on the cargo box 4 and measures the front-rear inclination (pitch) and left-right inclination (roll) of the cargo box 4 over time with respect to gravity (vertical direction) and outputs measurement data related to the measured inclination. The dump angle of the cargo box 4 relative to the truck chassis 2 is calculated by taking the difference between the measured value of the inclinometer 83 and the measured value of the inclinometer 82.

[0020] The special-purpose vehicle 1 is equipped with an estimation device 100 that estimates the weight of the cargo (loaded weight) based on data obtained from a pressure gauge 81 and an inclinometer 82. In this embodiment, the loaded weight represents the weight of the cargo loaded in the cargo box 4, and does not include the weight of the occupants riding in the special-purpose vehicle 1, the fuel loaded in the special-purpose vehicle 1, or the weight of the running gear and bodywork that constitute the special-purpose vehicle 1. The weight of the running gear and bodywork when the vehicle is not loaded is assumed to be known. The internal configuration of the estimation device 100 and the content of the processing performed by the estimation device 100 will be described in detail later, but in this embodiment, the loaded weight of the special-purpose vehicle 1 is estimated by utilizing the relationship between data including data on the magnitude of hydraulic pressure obtained from the pressure gauge 81 (first data), data on the inclinometer angle obtained from the inclinometer 82 (second data), and the loaded weight. The estimation device 100 is installed, for example, inside the cab 20. Alternatively, the estimation device 100 may be attached to the chassis frame 21.

[0021] In this embodiment, a dump truck equipped with a dumping device 3 is described as an example of a special-purpose vehicle 1. However, the special-purpose vehicle 1 is not limited to a dump truck, but may be any special-purpose vehicle equipped with a dumping device having a hydraulic cylinder, such as a dump-discharge type suction vehicle or a dump-discharge type refuse collection vehicle.

[0022] The configuration of the load weight estimation system according to this embodiment will be described below. Figure 4 is a block diagram illustrating the configuration of the load weight estimation system. The load weight display system includes an estimation device 100 that estimates the load weight of the special vehicle 1 based on data on the magnitude of hydraulic pressure obtained from a pressure gauge 81 and data on the inclination angle obtained from an inclinometer 82, and a display device 120 for notifying information regarding the load weight estimated by the estimation device 100.

[0023] The estimation device 100 is a dedicated or general-purpose computer and comprises a control unit 101, a storage unit 102, an operation unit 103, an input unit 104, an output unit 105, and a communication unit 106.

[0024] The control unit 101 includes, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The ROM in the control unit 101 stores control programs that control the operation of each hardware component of the estimation device 100. The CPU in the control unit 101 executes the control programs stored in the ROM and various computer programs stored in the memory unit 102 (described later), thereby controlling the operation of each hardware component and realizing the function of the estimation device 100 in this embodiment. The RAM in the control unit 101 temporarily stores data used during the execution of calculations.

[0025] The control unit 101 may also be equipped with functions such as a clock for outputting date and time information, a timer for measuring the elapsed time from the time a measurement start instruction is given until a measurement end instruction is given, and a counter for counting numbers.

[0026] The storage unit 102 is equipped with a storage device such as a hard disk or flash memory. The storage unit 102 stores computer programs executed by the control unit 101, various data acquired from external sources, and various data generated inside the estimation device 100.

[0027] The computer programs stored in the memory unit 102 include an estimation program PG1 for estimating the load weight of the special-purpose vehicle 1 by referring to the relationships between data including first data, second data, and load weight.

[0028] The computer programs stored in the storage unit 102 are provided, for example, by a non-temporary recording medium RM1 on which the computer programs are recorded in a readable format. The recording medium RM1 is, for example, a portable memory such as a CD-ROM, USB memory, or SD (Secure Digital) card. The control unit 101 reads various programs from the recording medium RM1 using a reading device (not shown in the figure) and stores the read programs in the storage unit 102. Alternatively, the computer programs stored in the storage unit 102 may be provided via communication. In this case, the control unit 101 downloads the necessary computer programs from a predetermined server and stores the downloaded computer programs in the storage unit 102.

[0029] Furthermore, the memory unit 102 includes a relationship table TB1 that defines the relationships between data including data on the magnitude of hydraulic pressure obtained from the pressure gauge 81 (first data), data on the inclination angle of the truck chassis 2 obtained from the inclinometer 82 (second data), and the load weight. The data on the inclination angle of the truck chassis 2 obtained from the inclinometer 82 (second data) can be considered as data on the inclination angle of the entire vehicle, i.e., the special-purpose vehicle 1. The configuration of the relationship table TB1 will be described in detail later. Note that the first data defined in the relationship table TB1 may be hydraulic pressure value data, or it may be converted weight data obtained by converting the hydraulic pressure value to load weight according to a predetermined relationship formula. The relationship formula used for conversion should be prepared according to the type of special-purpose vehicle 1 and hydraulic cylinder 52.

[0030] The operation unit 103 is composed of switches, buttons, etc., and accepts various operations. The control unit 101 performs appropriate processing based on the operations received through the operation unit 103. In this embodiment, the estimation device 100 is configured to include an operation unit 103, but the operation unit 103 is not essential, and operations may be accepted via externally connected equipment or a communication unit 106.

[0031] The input unit 104 is equipped with an interface for connecting various sensors, and sensors such as a pressure gauge 81 and inclinometers 82 and 83 are connected to it. These sensors may be connected to the input unit 104 by wire or by wireless connection. Measurement data related to the cylinder pressure of the hydraulic cylinder 52 output from the pressure gauge 81, measurement data related to the inclination of the special vehicle 1 output from the inclinometer 82, measurement data related to the inclination of the cargo box 4 output from the inclinometer 83, etc. are input to the input unit 104 as appropriate.

[0032] The output unit 105 is equipped with an output interface for connecting a display device 120, such as an LCD monitor. The display device 120 is installed, for example, near the driver's seat of the cab 20. Alternatively, the display device 120 may be installed on the rear side of the front panel 41. The output interface provided by the output unit 105 may be an output interface that outputs analog video signals, or it may be an output interface that outputs digital video signals such as DVI (Digital Visual Interface) or HDMI (High-Definition Multimedia Interface, registered trademark). For example, the output unit 105 outputs display data to the display device 120 in order to display the estimated load weight result on the display device 120.

[0033] In this embodiment, the display device 120 is connected to the outside of the estimation device 100, but the estimation device 100 may also be equipped with the display device 120.

[0034] The communication unit 106 is equipped with a communication interface for sending and receiving various types of data with external devices. An example of a party with which the estimation device 100 communicates via the communication unit 106 is various ECUs (Electronic Controller Units) and PLCs (Programmable Logic Controllers) mounted on the special-purpose vehicle 1. In this case, the communication unit 106 may be equipped with a communication port compliant with RS-485, for example, or a communication interface compliant with a communication standard for in-vehicle communication such as CAN (Controller Area Network), in order to communicate with the various ECUs and PLCs mounted on the special-purpose vehicle 1. Other examples of parties with which the estimation device 100 communicates via the communication unit 106 are server devices installed outside the special-purpose vehicle 1 or mobile terminals carried by the user. In this case, the communication unit 106 may be equipped with a communication interface compliant with wireless communication standards such as WiFi (registered trademark), 3G, 4G, 5G, or LTE (Long Term Evolution) in order to communicate with external server devices, etc.

[0035] Figure 5 is a conceptual diagram showing an example of the configuration of the relationship table TB1 in Embodiment 1. The relationship table TB1 stores the converted weight (i_weight) obtained from the hydraulic pressure value, the inclination angle (Pitch, Roll) of the special vehicle 1, and the load weight (a_weight) in association with each other. Here, the converted weight and inclination angle are input values, representing the first data (data related to the magnitude of hydraulic pressure) and the second data (data related to the inclination angle), respectively. On the other hand, the load weight is an output value given an input value, and represents the estimated load weight in the cargo box 4.

[0036] In Embodiment 1, the relational table TB1 stores the equivalent weight (i_weight) value in the range of 3.0 to 12.9 tons in 0.1-ton increments, the pitch angle (Pitch) value in the range of -8 to 8 degrees in 1-degree increments, and the roll angle (Roll) value in the range of 0 to 4 degrees in 1-degree increments. Regarding the roll angle, since the characteristics are nearly symmetrical, the absolute value can be used. However, there may be cases where the characteristics are not symmetrical, in which case the pitch angle and equivalent weight values ​​may be set for the roll angles on each side.

[0037] The input and output values ​​(estimated values) described above are converted into an address map and stored in the actual memory. When the control unit 101 is given input values ​​(i_weight, Pitch, Roll), it specifies an address and reads the load weight value (a_weight) from the relation table TB1. Based on the value read from the relation table TB1, the control unit 101 estimates the load weight in the cargo box 4.

[0038] Figure 6 is an explanatory diagram illustrating the method for calculating the load weight when input values ​​are given. The calculation method is explained using the example where the input values ​​are a converted weight of 8.55 tons, a pitch angle of 5.5 degrees, and a roll angle of 2.5 degrees. Assuming a three-dimensional space with the converted weight, pitch angle, and roll angle as coordinate axes, the points determined when the converted weight (i_weight) and inclination angle (Pitch, Roll) stored in relational table TB1 are specified (when an address is specified) represent grid points in the above three-dimensional space.

[0039] The point representing the input value mentioned above (indicated by a star in the figure) does not coincide with any of the grid points and is contained within a rectangular prism whose vertices are the eight grid points LP1 to LP8 shown in Figure 6. In this case, the control unit 101 specifies the eight grid points LP1 to LP8 (addresses) surrounding the point representing the input value and reads the value of the load weight (a_weight) stored in association with each grid point LP1 to LP8 (address) from the relational table TB1. For example, if the address corresponding to grid point LP1 (converted weight: 8.5 tons, pitch angle: 5 degrees, roll angle: 2 degrees) is specified, the value of 8.9 tons can be read as the load weight (a_weight). The same applies when the addresses corresponding to the other grid points LP2 to LP8 are specified.

[0040] The control unit 101 first calculates interval values ​​in the i_weight direction based on the values ​​read from grid points LP1 to LP8. For example, the control unit 101 calculates (9.0-8.9)×(8.55-8.5) / 0.1+8.9=8.95 as the interval value for LP1-LP2, and (9.1-9.0)×(8.55-8.5) / 0.1+9.0=9.05 as the interval value for LP3-LP4. The control unit 101 can do the same for the interval values ​​for LP5-LP6 and LP7-LP8.

[0041] The control unit 101 then calculates interval values ​​in the Pitch direction based on the interval values ​​in the i_weight direction that it has calculated. For example, the control unit 101 calculates (9.05-8.95)×(5.5-5) / 1+8.95=9.00 as the interval value for LP1,LP2-LP3,LP4, and calculates (9.05-8.95)×(5.5-5) / 1+8.95=9.00 as the interval value for LP5,LP6-LP7,LP8.

[0042] Finally, the control unit 101 calculates the interval values ​​for the Roll direction based on the interval values ​​for the Pitch direction that it has calculated. For example, the control unit 101 calculates (9.00-8.00)×(2.5-2) / 1+9.00=9.00 as the interval values ​​for L1, L2, L3, L4-L5, L6, L7, and L8.

[0043] Based on the above calculations, the control unit 101 obtains an estimated value of 9.00 tons as the estimated load weight when the input values ​​are converted weight: 8.55 tons, pitch angle: 5.5 degrees, and roll angle: 2.5 degrees.

[0044] In this embodiment, the interval values ​​for the i_weight direction, Pitch direction, and Roll direction are calculated in this order. However, the order in which the interval values ​​are calculated is not limited to the above and can be set as appropriate.

[0045] The following describes the procedure for estimating the load weight. Figure 7 is a flowchart illustrating the procedure for estimating the load weight using the relational table TB1. The control unit 101 of the estimation device 100 reads the estimation program PG1 from the storage unit 102 and executes it when the cargo box 4 is set to a predetermined dump angle relative to the truck chassis 2, thereby performing the following processes.

[0046] The control unit 101 acquires first data regarding the magnitude of the hydraulic pressure based on the output from the pressure gauge 81 (step S101). Specifically, the control unit 101 acquires measurement data (hydraulic pressure value of the hydraulic cylinder 52) output from the pressure gauge 81 through the input unit 104, and acquires first data by converting it to converted weight according to a predetermined conversion formula.

[0047] The control unit 101 acquires second data regarding the inclination angle of the special vehicle 1 based on the output from the inclinometer 82 (step S102). Specifically, the control unit 101 acquires the second data by acquiring the measurement data (pitch angle and roll angle of the special vehicle 1) output from the inclinometer 82 through the input unit 104.

[0048] In this embodiment, for convenience, the procedure is to acquire the first data and then the second data. However, the procedure may also be to acquire the second data and then the first data, or the first and second data may be acquired simultaneously.

[0049] The control unit 101 estimates the load weight in the cargo box 4 by referring to the relation table TB1 using the acquired first and second data as input values ​​(step S103). The control unit 101 identifies eight grid points surrounding the above input values ​​and reads the load weight value (a_weight) set as an output value in the relation table TB1 by specifying the address for each grid point. Based on the value read from the relation table TB1, the control unit 101 calculates the estimated load weight by sequentially determining the interval values ​​in the i_weight direction, pitch direction, and roll direction.

[0050] The control unit 101 notifies the estimated load weight (step S104). At this time, the control unit 101 outputs the estimated load weight information from the output unit 105 and displays it on the display device 120. Figure 8 is a schematic diagram showing an example of load weight display. Figure 8 shows an example in which the estimated load weight, load rate, and estimated date and time information are displayed as text information on the display device 120. Here, the estimated load weight is the value of the load weight estimated by referring to the relational table TB1. The load rate is a value calculated as the ratio of the load weight (estimated value) to the upper limit. The estimated date and time is the date and time when the load weight was estimated, and is information obtained, for example, from the built-in clock of the control unit 101. The control unit 101 generates data for the display screen based on the estimated load weight estimated by referring to the relationship table TB1, the load rate calculated as a percentage of the upper limit, and the date and time information obtained from the built-in clock. By outputting the generated display screen data to the display device 120, the display device 120 can display a screen like the one shown in Figure 8.

[0051] As described above, in Embodiment 1, the relationship table TB1, which stores the relationship between the hydraulic pressure value of the hydraulic cylinder 52, data on the inclination of the special vehicle 1, and the load weight in the cargo box 4, is referenced. Therefore, regardless of whether the special vehicle 1 is inclined or not, the load weight can be estimated with high accuracy, and the estimated load weight can be reported.

[0052] (Embodiment 2) Embodiment 2 describes the configuration of a relational table in which the granularity of each data is set such that the number of data points near the maximum load capacity is relatively dense, and the number of data points outside the maximum load capacity is sparse.

[0053] Figure 9 is a conceptual diagram showing an example of the configuration of relation table TB2 in Embodiment 2. Similar to relation table TB1 described in Embodiment 1, relation table TB2 stores the converted weight (i_weight) obtained from the hydraulic pressure value, the inclination angle (Pitch, Roll) of the special vehicle 1, and the load weight (a_weight) in association with each other.

[0054] In relational table TB2, the resolution for pitch angle and roll angle is 1 degree across the entire range, just like in relational table TB1. However, for equivalent weight (i_weight), the resolution is improved near the maximum load capacity of special-purpose vehicle 1. For example, if the maximum load capacity of special-purpose vehicle 1 is 10 tons, the resolution in the range of 9.00 to 10.99 tons should be 0.01 tons, and the resolution in the other ranges should be 0.1 tons. The range in which the resolution is improved and the resolution of each range can be set as appropriate, not limited to the above.

[0055] The input and output values ​​(estimated values) described above are converted into an address map and stored in the actual memory. When the control unit 101 is given input values ​​(i_weight, Pitch, Roll), it specifies an address and reads the load weight value (a_weight) from the relation table TB2. Based on the value read from the relation table TB2, the control unit 101 estimates the load weight in the cargo box 4.

[0056] The method for estimating the load weight is the same as in Embodiment 1. That is, the control unit 101 identifies eight grid points surrounding the input value and reads the value (a_weight) set as the output of the relation table TB2 by specifying the address for each grid point. Based on the value read from the relation table TB2, the control unit 101 can calculate an estimated load weight by sequentially determining interval values ​​in the i_weight direction, pitch direction, and roll direction.

[0057] As described above, in Embodiment 2, the granularity of the data in relational table TB2 is set, and the resolution is improved near the maximum load weight. Therefore, users attempting to load cargo up to near the maximum load weight can be informed of a more precise estimate of the load weight. Furthermore, in situations where the load rate is low and accurate weight measurement is not required for the user, the amount of data stored in the storage unit 102 can be reduced by making the number of data points in relational table TB2 sparser, thus eliminating the need for expensive equipment.

[0058] (Embodiment 3) Embodiment 3 describes a configuration for estimating the load weight by distinguishing between the state in which the cargo box 4 is raised and then stopped, and the state in which the cargo box 4 is lowered and then stopped.

[0059] The inventors of this invention investigated the relationship between the pitch angle of the truck chassis 2 and the hydraulic pressure in detail and found that there is a difference between the hydraulic pressure when the cargo box 4 is raised and then stopped, and the hydraulic pressure when the cargo box 4 is lowered and then stopped. Therefore, in the load weight estimation system of Embodiment 3, the state in which the cargo box 4 is raised and then stopped, and the state in which the cargo box 4 is lowered and then stopped are distinguished, and the load weight is estimated using different relationship tables for each.

[0060] Figure 10 is a block diagram illustrating the configuration of the load weight estimation system in Embodiment 3. The estimation device 100 comprises a control unit 101, a storage unit 102, an operation unit 103, an input unit 104, an output unit 105, and a communication unit 106. The configuration of each of these hardware parts is the same as that described in Embodiment 1, so their description is omitted.

[0061] The memory unit 102 includes a relational table TB10 for stopping upward movement and a relational table TB20 for stopping downward movement. The relational table TB10 for stopping upward movement is a table that defines the relationship between the converted weight (i_weight) and inclination angle (Pitch, Roll) data acquired when the cargo box 4 has stopped after rising, and the loaded weight. The relational table TB20 for stopping downward movement is a table that defines the relationship between the converted weight (i_weight) and inclination angle (Pitch, Roll) data acquired when the cargo box 4 has stopped after lowering, and the loaded weight. Relational tables TB10 and TB20 may be tables with constant resolution over the entire range, or they may be tables with improved resolution in the range near the maximum loaded weight.

[0062] Figure 11 is a flowchart illustrating the procedure for estimating the load weight in Embodiment 3. The control unit 101 of the estimation device 100 monitors the signal input through the input unit 104 to determine whether or not the weighing switch 89 is turned on (step S301). If it is not turned on (S301: NO), the control unit 101 waits until the weighing switch 89 is turned on.

[0063] When the weighing switch 89 is turned on (S301: YES), the control unit 101 starts the loading weight estimation process. When starting the estimation process, the control unit 101 may instruct the user to adjust the dump angle to a predetermined angle. The predetermined angle is, for example, an angle greater than 0.5 degrees and less than 1.5 degrees. The control unit 101 may give instructions by displaying text information on the display device 120, or by outputting sound from a speaker not shown in the figure. In Embodiment 3, the dump angle is adjusted manually using the operating lever 67.

[0064] The control unit 101 sequentially acquires measurement data of the inclination angle measured over time by the inclinometers 82 and 83 via the input unit 104, and detects the current dump angle based on the acquired measurement data (step S302). The control unit 101 can determine the dump angle by subtracting the inclination angle of the truck chassis 2, obtained as a measurement value from inclinometer 82, from the inclination angle of the cargo box 4, obtained as a measurement value from inclinometer 83. The control unit 101 stores the detected dump angle over time in the storage unit 102.

[0065] The control unit 101 determines whether the dump angle detected in step S302 is greater than the minimum angle θ1 (step S303). The minimum angle θ1 is a value set as the minimum value of the angle range suitable for measuring the load weight of the cargo box 4. An example of the minimum angle θ1 is 0.5 degrees.

[0066] If the control unit 101 determines that the current dump angle is less than or equal to the minimum angle θ1 (S303: NO), it instructs the user to raise the cargo box 4 (step S304). The control unit 101 instructs the user by displaying text information on the display device 120 indicating that the cargo box 4 should be raised. Alternatively, the control unit 101 may instruct the user by outputting an audio message from a speaker (not shown in the diagram) indicating that the cargo box 4 should be raised. Upon receiving the instruction, the user operates the operating lever 67 to raise the cargo box 4 to an appropriate angle and stop it. After giving instructions to the user, the control unit 101 returns to step S302.

[0067] If the control unit 101 determines that the current dump angle is greater than the minimum angle θ1 (S303: YES), it determines whether the current dump angle is less than the maximum angle θ2 (step S305). The maximum angle θ2 is set as the maximum value of the angle range suitable for measuring the load weight of the cargo box 4. An example of the maximum angle θ2 is 1.5 degrees.

[0068] If the control unit 101 determines that the current dump angle is greater than or equal to the maximum angle θ2 (S305: NO), it instructs the user to lower the cargo box 4 (step S306). The control unit 101 instructs the user, for example, by displaying text information on the display device 120 indicating that the cargo box 4 should be lowered. Alternatively, the control unit 101 may instruct the user by outputting an audio message from a speaker (not shown in the diagram) indicating that the cargo box 4 should be lowered. Upon receiving the instruction, the user operates the operating lever 67 to lower the cargo box 4 by an appropriate angle and stop it. After giving instructions to the user, the control unit 101 returns to step S302.

[0069] If the control unit 101 determines that the current dump angle is smaller than the maximum angle θ2 (S305: YES), it refers to the output of the built-in timer to determine whether a predetermined time has elapsed since the dump angle entered the set angle range (step S307). If the predetermined time has not elapsed (S307: NO), the control unit 101 waits until the predetermined time has elapsed.

[0070] If the control unit 101 determines that a predetermined time has elapsed (S307: YES), it determines whether the cargo box 4 was in a stationary state during the period up to the predetermined time (step S308). The control unit 101 can determine whether the cargo box 4 was in a stationary state by checking for any changes in the history data of the dump angle stored in the storage unit 102. If the cargo box 4 was not in a stationary state (S308: NO), the control unit 101 returns to step S302.

[0071] If the cargo box 4 remains stationary until a predetermined time has elapsed (S308: YES), the control unit 101 notifies the user that preparations for weighing the load are complete (step S309). The control unit 101 displays, for example, text information indicating that preparations for weighing the load are complete on the display device 120. Alternatively, the control unit 101 may output an audio message indicating that preparations for weighing the load are complete from a speaker not shown in the diagram.

[0072] Next, the control unit 101 determines whether the cargo box 4 stopped after rising (step S310). The control unit 101 can determine whether the cargo box 4 stopped after rising from the dump angle history data stored in the storage unit 102.

[0073] If the control unit 101 determines that the cargo box 4 has stopped after rising (S310: YES), it selects the relational table TB10 for stopping the upward movement as the table to refer to when estimating the load weight (step S311). On the other hand, if the control unit 101 determines that the cargo box 4 has stopped after descending (S310: NO), it selects the relational table TB20 for stopping the downward movement as the table to refer to when calculating the load weight (step S312).

[0074] The control unit 101 acquires first data (data relating to the magnitude of hydraulic pressure, including converted weight) based on the measurement results of the pressure gauge 81 and second data (data relating to the inclination of the special vehicle 1) based on the measurement results of the inclinometer 82, and estimates the load weight in the cargo box 4 by referring to the relational table TB10 for stopping the upward movement selected in step S311, or the relational table TB20 for stopping the downward movement selected in step S312 (step S313).

[0075] The method for estimating the load weight is the same as in Embodiment 1. That is, the control unit 101 identifies eight grid points surrounding the input value and specifies the address for each grid point, thereby reading the value (a_weight) set as the output of the relation table TB10 (or relation table TB20). Based on the value read from relation table TB10 (or relation table TB20), the control unit 101 can calculate an estimated load weight by sequentially determining the interval values ​​in the i_weight direction, Pitch direction, and Roll direction.

[0076] Next, the control unit 101 notifies the estimated load weight (step S314). At this time, the control unit 101 outputs the estimated load weight information from the output unit 105 and displays it on the display device 120. The control unit 101 may display the load weight information as text information on the display device 120, or it may use a schematic display method such as a graph display or a meter display. The control unit 101 may also be configured to output the estimated load weight information as sound from a speaker not shown in the diagram. After these processes are completed, the user operates the operation lever 67 to lower the cargo box 4 until the dump angle is 0 degrees. After that, the weighing is completed when the weighing switch 89 is turned off.

[0077] In Embodiment 3, the state in which the cargo box 4 is raised and then stopped, and the state in which the cargo box 4 is lowered and then stopped are distinguished, and different relationship tables are used to estimate the load weight for each state. Therefore, compared to the case in which a common table is used for both states, the decrease in estimation accuracy can be suppressed.

[0078] (Embodiment 4) Embodiment 4 describes a configuration in which the upward stopping operation is performed automatically.

[0079] Figure 12 is a block diagram illustrating the configuration of the load weight estimation system in Embodiment 4. The load weight estimation system according to Embodiment 4 comprises an estimation device 100 and a lifting control device 200 connected to the estimation device 100. The estimation device 100 is the same as that described in Embodiment 3 and comprises a control unit 101, a storage unit 102, an operation unit 103, an input unit 104, an output unit 105, and a communication unit 106. In Embodiment 4, only the relational table TB10 for stopping the lift is used, so the relational table TB20 for stopping the lowering does not need to be stored in the storage unit 102.

[0080] The lifting control device 200 comprises an input unit 201, a control unit 202, and an output unit 203, and controls the lifting and lowering of the cargo box 4 by controlling the operation of the hydraulic mechanism of the special-purpose vehicle 1. The input unit 201 is equipped with an input interface. The input unit 201 receives information output from the estimation device 100, operation information of the operating lever 67, operation information of the PTO switch 72, etc. The information input to the input unit 201 is output to the control unit 202.

[0081] The control unit 202 is configured, for example, by a PLC (Programmable Logic Controller). The control unit 202 generates control signals for raising and lowering the cargo box 4 based on information input through the input unit 201, according to the programmed logic. The control unit 202 outputs the generated control signals to the control valve 63 via the output unit 203. The output unit 203 is equipped with an output interface to which the control valve 63 and the estimation device 100 are connected. In this embodiment 4, the control valve 63 is configured as an electrically controllable electromagnetic control valve.

[0082] In this embodiment, the load weight estimation system is configured to include the estimation device 100 and the lifting control device 200 as separate components, but they may also be configured as an integrated unit.

[0083] Figure 13 is a flowchart illustrating the procedure for estimating the load weight in Embodiment 4. The control unit 101 of the estimation device 100 monitors the signal input through the input unit 104 to determine whether or not the weighing switch 89 is turned on (step S401). If it is not turned on (S401: NO), the control unit 101 waits until the weighing switch 89 is turned on.

[0084] If the metering switch 89 is turned on (S401: YES), the control unit 101 determines whether the PTO switch 72 is on or not (step S402). If the PTO switch 72 is not on (S402: NO), the control unit 101 instructs the user to turn on the PTO switch 72 (step S403) and switches the power transmission destination of the engine 70 to the hydraulic pump 61. The instruction to the user may be given by displaying text information on the display device 120, or by outputting it as sound from a speaker not shown in the figure.

[0085] If the PTO switch 72 is ON (S402: YES), the control unit 101 notifies the user that the dump angle will be adjusted (step S404). The control unit 101 displays, for example, text information indicating that the dump angle will be adjusted on the display device 120. Alternatively, the control unit 101 may output an audio message indicating that the dump angle will be adjusted from a speaker not shown in the diagram.

[0086] Next, the control unit 101 instructs the lifting control device 200 to raise the cargo box 4 (step S405). Specifically, the control unit 101 generates a control signal to instruct the lifting control device 200 to raise the cargo box 4, and outputs the generated control signal to the lifting control device 200 from the output unit 105, thereby giving instructions to the lifting control device 200. The control unit 202 of the lifting control device 200 raises the cargo box 4 by outputting a control signal to the control valve 63 in response to the instruction from the estimation device 100.

[0087] The control unit 101 sequentially acquires measurement data of the inclination angle measured over time by the inclinometers 82 and 83 via the input unit 104, and detects the current dump angle based on the acquired measurement data (step S406).

[0088] The control unit 101 determines whether the dump angle detected in step S406 is greater than the minimum angle θ1 (step S407). The minimum angle θ1 is a value set as the minimum value of the angle range suitable for measuring the load weight of the cargo box 4. An example of the minimum angle θ1 is 0.5 degrees.

[0089] If the control unit 101 determines that the current dump angle is less than or equal to the minimum angle θ1 (S407: NO), it returns the process to step S405 and continues the upward control of the cargo box 4.

[0090] If the control unit 101 determines that the current dump angle is greater than the minimum angle θ1 (S407: YES), it determines whether the current dump angle is less than the maximum angle θ2 (step S408). The maximum angle θ2 is set as the maximum value of the angle range suitable for measuring the load weight of the cargo box 4. An example of a maximum angle θ2 is 1.5 degrees.

[0091] If the control unit 101 determines that the current dump angle is greater than or equal to the maximum angle θ2 (S408: NO), it reports an error (step S409) because the tilt angle of the cargo box 4 is outside the angle range suitable for measuring the load weight, and terminates the process according to this flowchart. After reporting the error, the control unit 101 may instruct the lifting control device 200 to lower the cargo box 4.

[0092] If the control unit 101 determines that the current dump angle is less than the maximum angle θ2 (S408: YES), it instructs the lifting box 4 to stop after it has been raised (step S410). Specifically, the control unit 101 generates a control signal to instruct the lifting box 4 to stop, and outputs the generated control signal to the lifting control device 200 from the output unit 105, thereby giving instructions to the lifting control device 200. The control unit 202 of the lifting control device 200 stops the lifting box 4 by outputting a control signal to the control valve 63 in response to the instruction from the estimation device 100.

[0093] Next, the control unit 101 notifies the user that preparations for weighing the load are complete (step S411). For example, the control unit 101 displays text information indicating that preparations for weighing the load are complete on the display device 120. Alternatively, the control unit 101 may output audio information indicating that preparations for weighing the load are complete from a speaker not shown in the diagram.

[0094] Next, the control unit 101 sets the relationship table TB10 for stopping the lift as a table to be referenced when estimating the load weight (step S412). The control unit 101 acquires first data (data related to the magnitude of hydraulic pressure including converted weight) based on the measurement result of the pressure gauge 81 and second data (data related to the inclination of the special vehicle 1) based on the measurement result of the inclinometer 82, and estimates the load weight in the cargo box 4 by referring to the relationship table TB10 for stopping the lift selected in step S412 (step S413).

[0095] Next, the control unit 101 notifies the estimated load weight (step S414). At this time, the control unit 101 outputs the estimated load weight information from the output unit 105 and displays it on the display device 120. The control unit 101 may display the load weight information as text information on the display device 120, or it may use a schematic display method such as a graph display or a meter display. Alternatively, the control unit 101 may be configured to output the estimated load weight information as audio information from a speaker not shown in the diagram.

[0096] The control unit 101 may estimate the load weight and notify the user, and then instruct the lifting control device 200 to lower the cargo box 4. The control unit 202 of the lifting control device 200 will lower the cargo box 4 by outputting a control signal to the control valve 63 in response to the instruction from the estimation device 100.

[0097] When manually measuring the load weight, it is necessary to adjust the dump angle to a predetermined angle (for example, 1.0 degree), which can be cumbersome for the user. In contrast, in this embodiment, the load weight can be automatically measured by operating the weighing switch 89, thus reducing the inconvenience of operation.

[0098] (Embodiment 5) Embodiment 5 describes a configuration in which the load weight is estimated using a common relationship table TB30, whether the cargo box 4 is raised and then stopped, or lowered and then stopped.

[0099] Figure 14 is a block diagram illustrating the configuration of the load weight estimation system in Embodiment 5. The estimation device 100 comprises a control unit 101, a storage unit 102, an operation unit 103, an input unit 104, an output unit 105, and a communication unit 106. The configuration of each of these hardware parts is the same as that described in Embodiment 1, so their description is omitted.

[0100] The memory unit 102 includes a common relationship table TB30 for both cases: when the cargo box 4 is raised and then stopped, and when the cargo box 4 is lowered and then stopped. The configuration of the relationship table TB30 is the same as that of the relationship table TB1 described in Embodiment 1, and defines the relationship between the converted weight (i_weight) and inclination angle (Pitch, Roll) data and the loaded weight. The relationship table TB30 may be a table with constant resolution over the entire range, or it may be a table with improved resolution in the range near the maximum loaded weight.

[0101] In Embodiment 5, the control unit 101, as a preprocessing step for estimating the load weight using the relational table TB30, converts the hydraulic pressure value to the converted weight using the relational expression for stopping the rise (first relational expression) when the cargo box 4 is raised and then stopped, and converts the hydraulic pressure value to the converted weight using the relational expression for stopping the lowering (second relational expression) when the cargo box 4 is lowered and then stopped. The functional forms of these relational expressions are predetermined such that, if the measurement conditions are the same, the converted weight converted from the hydraulic pressure value after stopping the rise and the converted weight converted from the hydraulic pressure value after stopping the lowering show the same value. Each relational expression is stored in the storage unit 102. When the control unit 101 obtains the hydraulic pressure value after stopping the rise, it reads the relational expression for stopping the rise from the storage unit 102 and converts the hydraulic pressure value to the converted weight, and when it obtains the hydraulic pressure value after stopping the lowering, it reads the relational expression for stopping the lowering from the storage unit 102 and converts the hydraulic pressure value to the converted weight. This makes it possible to uniquely calculate the converted weight regardless of whether the stop is from rising or lowering. The control unit 101 estimates the load weight by referring to the relationship table TB30 based on the converted weight.

[0102] Figure 15 is a flowchart illustrating the procedure for estimating the load weight in Embodiment 5. The control unit 101 of the estimation device 100 completes the weighing preparation in the same procedure as S301 to S309 in the flowchart shown in Figure 11, and notifies the user that the weighing preparation is complete (steps S501 to S509). After the weighing preparation is complete, the loading operation is performed. The control unit 101 acquires first data (oil pressure value) based on the measurement result of the pressure gauge 81 and second data (tilt angle of the special vehicle 1) based on the measurement result of the inclinometer 82 as needed.

[0103] After notifying the user that preparations for weighing the load are complete, the control unit 101 determines whether the cargo box 4 has stopped after rising (step S510). If the control unit 101 determines that the cargo box 4 has stopped after rising (S510: YES), it reads the relational expression for stopping the upward movement from the storage unit 102 and converts the hydraulic pressure values ​​measured during the loading operation into a converted weight (step S511). On the other hand, if the control unit 101 determines that the cargo box 4 has stopped after descending (S510: NO), it reads the relational expression for stopping the downward movement from the storage unit 102 and converts the hydraulic pressure values ​​measured during the loading operation into a converted weight (step S512).

[0104] The control unit 101 estimates the load weight in the cargo box 4 by referring to the relational table TB30 based on the converted weight converted in step S511 or step S512 (step S513). The method for estimating the load weight using the relational table TB30 is the same as in Embodiment 1.

[0105] Next, the control unit 101 notifies the estimated load weight (step S514). At this time, the control unit 101 outputs the estimated load weight information from the output unit 105 and displays it on the display device 120. The control unit 101 may display the load weight information as text information on the display device 120, or it may use a schematic display method such as a graph display or a meter display. The control unit 101 may also be configured to output the estimated load weight information as sound from a speaker not shown in the diagram. After these processes are completed, the user operates the operation lever 67 to lower the cargo box 4 until the dump angle is 0 degrees. After that, the weighing is completed when the weighing switch 89 is turned off.

[0106] As described above, in Embodiment 5, the relational formula for stopping the upward movement and the relational formula for stopping the downward movement are used in combination to calculate the converted weight, eliminating the difference between the hydraulic pressure value at the time of upward movement stopping and the hydraulic pressure value at the time of downward movement stopping. Therefore, it is not necessary to prepare two types of relational tables (a relational table for stopping the upward movement and a relational table for stopping the downward movement) in order to estimate the load weight from the converted weight, and the load weight can be estimated even with an estimation device 100 that has a relatively small storage capacity in the memory unit 102.

[0107] (Embodiment 6) Embodiment 6 describes a configuration in which the relationship (third relational equation) between the hydraulic pressure value measured after the upward movement stops and the hydraulic pressure value measured after the downward movement stops is understood, and either the hydraulic pressure value after the upward movement stops or the hydraulic pressure value after the downward movement stops is corrected using the third relational equation.

[0108] The configuration of the estimation device 100 in Embodiment 6 is the same as that described in Embodiment 5. That is, the estimation device 100 in Embodiment 6 includes a common relational table TB30 for both the state in which the cargo box 4 is raised and then stopped, and the state in which the cargo box 4 is lowered and then stopped.

[0109] In Embodiment 6, it is assumed that the relationship between the hydraulic pressure value measured after the cargo box 4 stops rising and the hydraulic pressure value measured after the cargo box 4 stops descending is known in advance. For example, assuming the same measurement conditions, it is assumed that there is a relationship between the hydraulic pressure value PV1 measured after the cargo box 4 stops rising and the hydraulic pressure value PV2 measured after the cargo box 4 stops descending, such that PV1 = PV2 + ΔPV. ΔPV is the differential pressure between PV1 and PV2, and is assumed to be known in Embodiment 6. The relational expression (third relational expression) showing this relationship is stored in the storage unit 102.

[0110] When the control unit 101 obtains the hydraulic pressure value PV1 measured after the ascent stops, it converts the obtained hydraulic pressure value PV1 into a converted weight according to a predetermined relational expression, and then estimates the load weight by referring to the relational table TB30 based on the converted weight. On the other hand, when the control unit 101 obtains the hydraulic pressure value PV2 measured after the descent stops, it corrects the hydraulic pressure value PV2 according to a third relational expression stored in the memory unit 102. That is, the control unit 101 corrects the obtained hydraulic pressure value PV2 by adding the difference ΔPV. After the corrected hydraulic pressure value (=PV2+ΔPV) is converted into a converted weight according to the predetermined relational expression mentioned above, the control unit 101 estimates the load weight by referring to the relational table TB30.

[0111] Figure 16 is a flowchart illustrating the procedure for estimating the load weight in Embodiment 6. The control unit 101 of the estimation device 100 completes the weighing preparation in the same procedure as S301 to S309 in the flowchart shown in Figure 11, and notifies the user that the weighing preparation is complete (steps S601 to S609). After the weighing preparation is complete, the loading operation is performed. The control unit 101 acquires first data (oil pressure value) based on the measurement result of the pressure gauge 81 and second data (tilt angle of the special vehicle 1) based on the measurement result of the inclinometer 82 as needed.

[0112] After notifying the user that preparations for weighing the load weight are complete, the control unit 101 determines whether the cargo box 4 has stopped after rising (step S610). If the control unit 101 determines that the cargo box 4 has stopped after rising (S610: YES), it converts the hydraulic pressure value P1 after the rise has stopped to the converted weight according to a predetermined relational expression (step S611). On the other hand, if the control unit 101 determines that the cargo box 4 has stopped after descending (S610: NO), it adds the differential pressure ΔPV to the hydraulic pressure value P2 after the descending has stopped (step S612). Then, the control unit 101 proceeds to step S611 and converts the hydraulic pressure value with the differential pressure added (=PV2+ΔPV) to the converted weight according to a predetermined relational expression (step S611).

[0113] The control unit 101 estimates the load weight in the cargo box 4 by referring to the relational table TB30 based on the converted weight converted in step S611 (step S613). The method for estimating the load weight using the relational table TB30 is the same as in Embodiment 1.

[0114] Next, the control unit 101 notifies the estimated load weight (step S614). At this time, the control unit 101 outputs the estimated load weight information from the output unit 105 and displays it on the display device 120. The control unit 101 may display the load weight information as text information on the display device 120, or it may use a schematic display method such as a graph display or a meter display. The control unit 101 may also be configured to output the estimated load weight information as sound from a speaker not shown in the diagram. After these processes are completed, the user operates the operation lever 67 to lower the cargo box 4 until the dump angle is 0 degrees. After that, the weighing is completed when the weighing switch 89 is turned off.

[0115] As described above, in Embodiment 6, the relationship between the hydraulic pressure value measured after the upward movement stops and the hydraulic pressure value measured after the downward movement stops is known. For example, the hydraulic pressure value measured after the downward movement stops can be corrected to be equivalent to the hydraulic pressure value measured after the upward movement stops under the same conditions. Therefore, it is no longer necessary to prepare two types of relationship tables (a relationship table for upward movement stops and a relationship table for downward movement stops) in order to estimate the load weight from the hydraulic pressure value (converted weight), and the load weight can be estimated even with an estimation device 100 that has a relatively small storage capacity in the memory unit 102.

[0116] In this embodiment, the differential pressure is added to the hydraulic pressure value obtained after the descent stops, but it may also be configured to subtract the differential pressure from the hydraulic pressure value obtained after the ascent stops. Furthermore, the hydraulic pressure value may be corrected using any relational expression, not limited to adding (or subtracting) the differential pressure.

[0117] (Embodiment 7) Embodiment 7 describes how to create the relational table TB1.

[0118] Embodiment 7 describes a configuration in which a relational table TB1 is created on an external server device 500. Figure 17 is a block diagram illustrating the configuration of the server device 500 in Embodiment 7. The server device 500 is a dedicated or general-purpose computer and comprises a control unit 501, a storage unit 502, a communication unit 503, an operation unit 504, and a display unit 505.

[0119] The control unit 501 includes, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The ROM in the control unit 501 stores control programs that control the operation of each hardware component of the server device 500. The CPU in the control unit 501 executes the control programs stored in the ROM and various computer programs stored in the memory unit 502 (described later), thereby controlling the operation of each hardware component and realizing the functions of the server device 500 in this embodiment. The RAM in the control unit 501 temporarily stores data used during calculation execution.

[0120] The control unit 501 is configured to include a CPU, ROM, and RAM, but alternatively, it may include one or more arithmetic circuits or control circuits that include a GPU (Graphics Processing Unit), FPGA (Field Programmable Gate Array), DSP (Digital Signal Processor), quantum processor, volatile or non-volatile memory, etc. Furthermore, the control unit 501 may include functions such as a clock for outputting date and time information, a timer for measuring the elapsed time from the start of measurement to the end of measurement, and a counter for counting numbers.

[0121] The storage unit 502 is equipped with a storage device such as a hard disk or flash memory. The storage unit 502 stores computer programs executed by the control unit 501, various data acquired from external sources, and various data generated inside the server device 500.

[0122] The computer program stored in the memory unit 502 includes a learning program PG2 for generating a learning model LM1. Here, the learning model LM1 is configured to output data on load weight when it receives first data (data on hydraulic pressure including converted weight) and second data (data on the inclination of the special vehicle 1). The configuration of the learning model LM1 will be described in detail later.

[0123] These computer programs may be provided on a non-temporary recording medium RM2 on which the computer programs are recorded in a readable format. The recording medium RM2 is, for example, a portable memory such as a CD-ROM, USB memory, or SD card. The control unit 501 reads various programs from the recording medium RM2 using a reading device (not shown in the figure) and stores the read programs in the storage unit 502. Alternatively, the computer programs may be provided by communication.

[0124] The communication unit 503 is equipped with a communication interface for connecting to a communication network such as the Internet. The interface provided by the communication unit 503 is a communication interface conforming to wireless communication standards such as WiFi (registered trademark), 3G, 4G, 5G, and LTE (Long Term Evolution). The communication unit 503 transmits various information to be notified externally and receives various information transmitted from external sources to itself.

[0125] The operation unit 504 is equipped with input devices such as a keyboard and mouse, and accepts input of various types of information. The control unit 501 performs appropriate control based on the information input from the operation unit 504, and stores the input information in the storage unit 502 as needed.

[0126] The display unit 505 is equipped with a display device such as a liquid crystal display panel or an organic EL display panel, and displays information that should be notified to an administrator or the like based on the control signal output from the control unit 501.

[0127] Figure 18 is a schematic diagram illustrating an example configuration of the learning model LM1. In this embodiment, the learning model LM1 is, for example, a support vector regression model and comprises an input layer into which various data are input, an intermediate layer including a kernel that performs predetermined calculations based on the data input to the input layer, and an output layer that combines the outputs from the intermediate layer and outputs the calculation results.

[0128] The input, hidden, and output layers of the LM1 learning model each contain one or more nodes, and the nodes in each layer are connected to the nodes in the preceding and succeeding layers by coupling weights in a unidirectional direction. In a nonlinearly extended support vector machine using the kernel trick, the coupling weights from the hidden layer to the output layer are adaptively determined through learning. On the other hand, the coupling weights from the input layer to the hidden layer are fixed and are mechanically determined from the training data.

[0129] The input layer of the learning model LM1 receives two sets of data: the first set of data (data related to the magnitude of hydraulic pressure, including converted weight) and the second set of data (data related to the inclination of special vehicle 1). The data input to the input layer is weighted by the coupling loads determined using the training data and output to the hidden layer. The hidden layer performs calculations using kernels based on the data input from the input layer. The data calculated in each kernel of the hidden layer is weighted by the coupling loads determined through learning and output to the output layer. The output layer combines the data input from the hidden layer to output the calculation result regarding the load weight.

[0130] Here, the calculation result output by the output layer may be an estimated value of the load weight, or it may be the probability that the load weight is a certain value. In the latter case, the output layer is composed of multiple nodes, and the first node should output the probability that the load weight is 1 ton, the second node the probability that the load weight is 2 tons, ..., and the Nth node (where N is an integer greater than or equal to 2) the probability that the load weight is N tons, and so on, outputting the probability that the load weight is a certain value.

[0131] The server device 500 prepares training data to generate the learning model LM1. Figure 19 is a conceptual diagram of the training data. The training data includes the hydraulic pressure of the hydraulic cylinder 52 measured with a fixed load, and the inclination angle (pitch angle and roll angle) of the special vehicle 1. In the example in Figure 19, the training data includes hydraulic pressure and inclination angle measured under various conditions with a 3-ton (measured) load in the cargo box 4 of the special vehicle 1, hydraulic pressure and inclination angle measured under various conditions with a 4-ton (measured) load in the cargo box 4 of the special vehicle 1, and hydraulic pressure and inclination angle measured under various conditions with a 5-ton (measured) load in the cargo box 4 of the special vehicle 1, etc.

[0132] Alternatively, the results of CAE (Computer-Aided Engineering) analysis may be used as training data instead of, or in conjunction with, the measured values ​​mentioned above.

[0133] Figure 20 is a flowchart illustrating the first method for generating the learning model LM1. The control unit 501 of the server device 500 reads the learning program PG2 from the storage unit 502 and executes it, thereby performing the following processes.

[0134] The control unit 501 selects a set of data from the training data (step S701). The training data includes a series of measurement data taken at the same time and the value of the load weight at the time these measurement data were obtained.

[0135] Next, the control unit 501 inputs the selected training data to the learning model LM1 (step S702) and performs calculations using the learning model LM1 (step S703). That is, the control unit 501 inputs measurement data such as converted weight and inclination angle to the nodes constituting the input layer of the learning model LM1, performs calculations using the kernel of the intermediate layer, and outputs the calculation results from the output layer. Initial values ​​are provided to the definition information describing the learning model LM1 in the initial stage before learning begins.

[0136] Next, the control unit 501 evaluates the calculation result obtained in step S703 (step S704) and determines whether or not learning is complete (step S705). Specifically, the control unit 501 can evaluate the calculation result using an error function (also called an objective function, loss function, or cost function) based on the calculation result obtained in step S703 and the training data. For example, the control unit 501 may determine that learning is complete if the error function becomes below (or above) a threshold during the process of optimizing (minimizing or maximizing) the error function using a gradient descent method such as the steepest descent method. In addition, to avoid the problem of overfitting, techniques such as cross-validation and early termination may be incorporated to terminate learning at an appropriate time.

[0137] If it is determined that learning is not complete (S705: NO), the control unit 501 updates the coupling loads between nodes of the learning model LM1 (step S706), returns to step S701, and continues learning using different training data. The control unit 501 can update the coupling loads between nodes using a backpropagation method, which sequentially updates the coupling loads between nodes from the output layer to the input layer of the learning model LM1.

[0138] If the control unit 501 determines that learning is complete (S705: YES), it stores the learned model LM1 in the storage unit 502 (step S707) and terminates the process according to this flowchart.

[0139] If training data obtained from CAE analysis and training data obtained from actual measurements are available, the learning model LM1 may be generated using this training data.

[0140] Figure 21 is a flowchart illustrating the second method for generating the learning model LM1. The storage unit 502 of the server device 500 is assumed to store training data obtained from CAE analysis and training data obtained from measured values.

[0141] The control unit 501 acquires training data (CAE data) from the memory unit 502 through CAE analysis (step S721) and performs learning using the CAE data (step S722). The learning procedure is the same as the procedure in the flowchart shown in Figure 20, where a set of data is selected from the training data through CAE analysis, input into the model to be learned and calculations are performed, and the calculation results are evaluated using an error function based on the calculation results and the training data to proceed with learning. The control unit 501 generates an initial model through learning using the CAE data.

[0142] Next, the control unit 501 acquires real data from the memory unit 502 (step S723) and performs additional learning using the real data (step S724). The control unit 501 can generate the learning model LM1 by performing additional learning on the initial model generated by the learning in step S722. The learning procedure is the same as the procedure in the flowchart shown in Figure 20, in which a set of data is selected from the training data consisting of measured values, input into the model to be learned (initial model) and calculations are performed, and the calculation results are evaluated using an error function based on the calculation results and the training data to proceed with learning.

[0143] As described above, the control unit 501 can generate a learning model LM1 that outputs data on load weight when it receives first data (data on hydraulic pressure including converted weight) and second data (data on the inclination of the special vehicle 1).

[0144] The control unit 501 can create a relation table TB1 using the generated learning model LM1. That is, the control unit 501 inputs the first data and the second data with a desired resolution into the learning model LM1 and performs calculations using the learning model LM1 to obtain the estimated load weight value. By storing the input first data and the second data, as well as the load weight value output from the learning model LM1, as a table, the relation table TB1 can be created. Furthermore, using a similar procedure, a relation table TB2 with improved resolution near the maximum load weight, a relation table TB10 for stopping ascent, and a relation table TB20 for stopping descent can be created.

[0145] The relational table TB1(TB2,TB10,TB20) created in the server device 500 is provided to the estimation device 100 of the special vehicle 1. The relational table TB1(TB2,TB10,TB20) provided to the estimation device 100 is stored in the memory unit 102 and referenced when estimating the load weight.

[0146] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not in the sense described above, and all modifications within the sense and scope equivalent to the claims are intended.

[0147] For example, in this embodiment, a dump truck was described as a special-purpose vehicle 1, which includes an estimation device 100 for estimating the load weight, a display device 120 for notifying information regarding the load weight estimated by the estimation device 100, and a dumping device 3. However, the present invention is not limited to dump trucks and can be applied to various special-purpose vehicles equipped with a dumping device having a hydraulic cylinder. For example, it can be applied to special-purpose vehicles such as dump-discharge type suction vehicles, dump-discharge type refuse collection vehicles, and container detachment vehicles equipped with a cargo handling arm. [Explanation of Symbols]

[0148] 1. Special-purpose vehicle 2 Truck Chassis 3. Dumping device 4 packing boxes 5. Hoist mechanism 20 Cab 21 Chassis Frame 22F front wheel 22R rear wheel 23F,23R Axle 30 Subframes 81 Pressure gauge 82 Inclinometer (Chassis) 83 Inclinometer (packing box) 100 Estimator 101 Control Unit 102 Storage section 103 Operation section 104 Input section 105 Output section 106 Communications Department PG1 Estimation Program TB1,TB2 Relationship Table

Claims

1. Regarding a special-purpose vehicle equipped with a hydraulic actuator for raising and lowering a cargo box, a first acquisition unit acquires first data regarding the magnitude of the hydraulic pressure based on the output from a pressure gauge that measures the magnitude of the hydraulic pressure acting on the hydraulic actuator, A second acquisition unit acquires second data relating to the inclination angle based on the output from an inclinometer that measures the inclination angle of the special-purpose vehicle, A storage unit that stores the relationship between the first data, the second data, and data including the load weight in the cargo box, When the first and second data are obtained, an estimation unit estimates the load weight in the cargo box by referring to the relationship between the data stored in the storage unit. Equipped with, The aforementioned relationship defines the relationship between the converted weight obtained by converting the magnitude of the hydraulic pressure into weight, the inclination angle, and the discrete values ​​of the load weight. The estimation unit, The load weight in the cargo box is estimated based on the interval value corresponding to the first data in an interval determined by the discrete values ​​of the converted weight, and the interval value corresponding to the second data in an interval determined by the discrete values ​​of the inclination angle. A system for estimating the load capacity of specially equipped vehicles.

2. The relationships between the aforementioned data are such that the number of data points near the maximum load capacity is relatively dense, and the number of data points outside the maximum load capacity is relatively sparse, by setting the granularity of each data point. The load weight estimation system according to claim 1.

3. The system further includes an information processing device that creates relationships between the data using a learning model configured to output data relating to the load weight in the cargo box in response to the input of the first data and the second data. A load weight estimation system according to claim 1 or claim 2.

4. The aforementioned information processing device is A first generation unit generates an initial model configured to output data related to the load weight in response to the input of the first data and the second data, using the analysis results of CAE (Computer-Aided Engineering) analysis as training data, A second generation unit generates the learning model by further learning the initial model using the first data obtained from the output of the pressure gauge, the second data obtained from the output of the inclinometer, and the measured value of the load weight as training data for additional learning. The load weight estimation system according to claim 3, comprising:

5. The storage unit stores a first relationship representing the relationship between the data to be referenced when the cargo box stops after rising, and a second relationship representing the relationship between the data to be referenced when the cargo box stops after lowering. The estimation unit estimates the load weight in the cargo box by referring to either the first relationship or the second relationship, depending on whether the cargo box stopped after rising or after lowering. A load weight estimation system according to any one of claims 1 to 4.

6. The storage unit stores a first relational expression for converting the first data acquired by the first acquisition unit after the upward movement of the cargo box stops into a converted weight, and a second relational expression for converting the first data acquired by the first acquisition unit after the downward movement of the cargo box stops into a converted weight. The aforementioned relationship defines the relationship between the converted weight converted by the first or second relational expression, the second data, and the data including the loaded weight in the cargo box. A load weight estimation system according to any one of claims 1 to 4.

7. The storage unit stores a third relational expression that represents the relationship between the first data acquired by the first acquisition unit after the upward movement of the cargo box stops and the first data acquired by the first acquisition unit after the downward movement of the cargo box stops. Correction unit corrects either the first data acquired after the upward movement of the cargo box stops, or the first data acquired after the downward movement of the cargo box stops, using the third relational expression. A load weight estimation system according to any one of claims 1 to 4, comprising:

8. Regarding a special-purpose vehicle equipped with a hydraulic actuator for raising and lowering a cargo box, first data regarding the magnitude of the hydraulic pressure acting on the hydraulic actuator is obtained based on the output from a pressure gauge that measures the magnitude of the hydraulic pressure acting on the hydraulic actuator. Based on the output from the inclinometer that measures the inclination angle of the special-purpose vehicle, a second data set relating to the inclination angle is obtained. The load weight in the cargo box is estimated by referring to the relationship between the first data, the second data, and the data including the load weight in the cargo box. A method for estimating the load weight of a specially equipped vehicle, which is performed by computer, The aforementioned relationship defines the relationship between the converted weight obtained by converting the magnitude of the hydraulic pressure into weight, the inclination angle, and the discrete values ​​of the load weight. The load weight in the cargo box is estimated based on the interval value corresponding to the first data in an interval determined by the discrete values ​​of the converted weight, and the interval value corresponding to the second data in an interval determined by the discrete values ​​of the inclination angle. A method for estimating the load weight of a specially equipped vehicle, wherein the processing is performed by the computer.

9. On the computer, Regarding a special-purpose vehicle equipped with a hydraulic actuator for raising and lowering a cargo box, first data regarding the magnitude of the hydraulic pressure acting on the hydraulic actuator is obtained based on the output from a pressure gauge that measures the magnitude of the hydraulic pressure acting on the hydraulic actuator. Based on the output from the inclinometer that measures the inclination angle of the special-purpose vehicle, a second data set relating to the inclination angle is obtained. The load weight in the cargo box is estimated by referring to the relationship between the first data, the second data, and the data including the load weight in the cargo box. A computer program for executing a process, The aforementioned relationship defines the relationship between the converted weight obtained by converting the magnitude of the hydraulic pressure into weight, the inclination angle, and the discrete values ​​of the load weight. The load weight in the cargo box is estimated based on the interval value corresponding to the first data in an interval determined by the discrete values ​​of the converted weight, and the interval value corresponding to the second data in an interval determined by the discrete values ​​of the inclination angle. A computer program that causes the computer to perform a process.

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