Specially equipped vehicle load weight estimation system, specially equipped vehicle load weight estimation method, 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: an acquisition unit for acquiring 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 correction unit for correcting data acquired by the acquisition unit; and an estimation unit for estimating the weight of the load in the cargo box on the basis of the corrected data.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a system for estimating the load weight of a specially equipped vehicle, a method for estimating the load weight of a specially equipped vehicle, and a computer program. [Background technology]

[0002] Specially equipped vehicles such as trucks are equipped with a hydraulic mechanism for tilting the loading platform. Patent Document 1 discloses a system that acquires measurement data including the cylinder pressure of a hydraulic cylinder provided in the hydraulic mechanism and estimates the load weight on the loading platform based on the acquired measurement data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-103138 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the zero point of the load weight fluctuates due to aging, temperature changes, or the like, it is not possible to accurately estimate the load weight.

[0005] The present invention aims to provide a special purpose vehicle load weight estimation system, a special purpose vehicle load weight estimation method, and a computer program that can accurately estimate the load weight by calibrating acquired data. [Means for solving the problem]

[0006] A special purpose vehicle load weight estimation system according to one embodiment of the present invention includes an acquisition unit that acquires data regarding 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 a special purpose vehicle equipped with a hydraulic actuator for raising and lowering a cargo box, a calibration unit that calibrates the data acquired by the acquisition unit, and an estimation unit that estimates the load weight of the cargo box based on the calibrated data.

[0007] A method for estimating the load weight of a special purpose vehicle according to one aspect of the present invention involves acquiring data on 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, calibrating the acquired data, and using a computer to estimate the load weight of the cargo box based on the calibrated data.

[0008] A computer program according to one aspect of the present invention is a computer program for causing a computer to acquire data regarding the magnitude of hydraulic pressure acting on a hydraulic actuator for a special purpose vehicle equipped with the hydraulic actuator for raising and lowering a cargo box based on the output from the pressure gauge that measures the magnitude of the hydraulic pressure acting on the hydraulic actuator, calibrate the acquired data, and execute a process of estimating the load weight of the cargo box based on the calibrated data. [Effects of the Invention]

[0009] According to the present invention, the loaded weight can be accurately estimated by calibrating the acquired data. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view showing the overall configuration of a specially equipped vehicle according to a first embodiment. [Figure 2] 1 is a plan view showing the overall configuration of a specially equipped vehicle according to a first embodiment. [Figure 3] FIG. 10 is a side view of the packing box in an upright position. [Figure 4]FIG. 1 is a block diagram illustrating a configuration of a loaded weight estimation system. [Figure 5] 4 is a flowchart illustrating a procedure for estimating a loaded weight in the first embodiment. [Figure 6] FIG. 10 is a schematic diagram showing an example of a load weight display. [Figure 7] FIG. 2 is a conceptual diagram showing an example of the structure of a relationship table in the first embodiment. [Figure 8] FIG. 10 is an explanatory diagram illustrating a method for calculating a load weight when an input value is given. [Figure 9] FIG. 10 is a block diagram illustrating the configuration of a loaded weight estimation system according to a second embodiment. [Figure 10] 10 is a flowchart illustrating a procedure for estimating a loaded weight in the second embodiment. [Figure 11] FIG. 10 is a block diagram illustrating the configuration of a loaded weight estimation system according to a third embodiment. [Figure 12] 11 is a flowchart illustrating a procedure for estimating a loaded weight in the third embodiment. [Figure 13] FIG. 10 is a block diagram illustrating the configuration of a loaded weight estimation system according to a fourth embodiment. [Figure 14] 13 is a flowchart illustrating a procedure for estimating a loaded weight in the fourth embodiment. [Figure 15] 13 is a flowchart illustrating a procedure for estimating a loaded weight in the fifth embodiment. [Figure 16] FIG. 20 is a block diagram illustrating the configuration of a server device according to a sixth embodiment. [Figure 17] FIG. 1 is a schematic diagram illustrating an example of the configuration of a learning model. [Figure 18] FIG. 1 is a conceptual diagram of training data. [Figure 19] 10 is a flowchart illustrating a first method for generating a learning model. [Figure 20] 10 is a flowchart illustrating a second method for generating a learning model. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will now be described in detail with reference to the drawings showing embodiments thereof. (Embodiment 1) Fig. 1 is a side view showing the overall configuration of a specially equipped vehicle 1 according to a first embodiment, Fig. 2 is a plan view thereof, and Fig. 3 is a side view in a state where a cargo box is upright. The specially equipped vehicle 1 illustrated in Figs. 1 to 3 is a dump truck equipped with a truck chassis 2 which is a traveling section, and a dump device 3 which is an example of a mounting device mounted on the traveling section. In the following description, the front-rear, left-right, and up-down directions refer to the front-rear, left-right, and up-down directions as seen from a driver sitting in the driver's seat of the truck chassis 2. For the sake of explanation, Fig. 2 shows a state in which the dump device 3 has been removed.

[0012] The truck chassis 2 includes 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 (vertical joists) 21A, 21A extending in the front-to-rear direction, and a plurality of cross members (horizontal joists) 21B, ..., 21B that connect the pair of left and right main frames 21A, 21A (see FIG. 2). Front wheels 22F and rear wheels 22R, 22R of the truck chassis 2 are rotatably attached to the main frames 21A, 21A via suspension devices (not shown). The truck chassis 2 includes an engine 70 (prime mover) and a transmission connected to the engine 70 via a clutch, and is configured to travel by transmitting driving force from the engine 70 to a drive system of drive wheels (e.g., front wheels 22F) via the transmission.

[0013] The dumping apparatus 3 comprises a subframe 30 fixed onto the chassis frame 21, and a cargo box 4 supported by the subframe 30 and in which loads such as earth and sand are loaded. The cargo box 4 is supported rotatably around a hinge shaft 31 extending in the left-right direction at the rear end of the subframe 30. The cargo box 4 is a box body with an open top, and comprises a front panel 41 arranged to surround a rectangular bottom 40, a pair of left and right side panels 42, and a rear panel (rear flap) 43. The rear panel 43 is configured to be openable and closable.

[0014] The dump 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 the cargo box 4 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 referred to as the cargo box 4 rising. On the other hand, when the hydraulic cylinder 52 of the hoist mechanism 5 is contracted, the front of the cargo box 4 is lowered and the cargo box 4 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 referred to as the cargo box 4 falling.

[0015] The hydraulic mechanism that extends and retracts the hydraulic cylinder 52 includes a hydraulic pump 61, a hydraulic oil tank 62, and a control valve 63. The hydraulic pump 61, which is a hydraulic supply source, is driven by power from an engine 70 transmitted via a PTO (Power Take-Off) 71, thereby pumping up hydraulic oil in the hydraulic oil tank 62 through hydraulic piping 64 and supplying the hydraulic oil (pressurized oil) to the hydraulic cylinder 52 through a main pipe 65 connected to a discharge port. Note that a PTO switch 72 provided in the cab 20 switches between connecting and disconnecting the power transmission of the engine 70.

[0016] The supply direction of hydraulic oil discharged from the hydraulic pump 61 is switched by a control valve 63 operated by a manual operation lever 67. For example, when the control valve 63 is in the neutral position by operation of the operation lever 67, hydraulic oil is not supplied from the hydraulic pump 61 to the hydraulic cylinder 52, and the cargo box 4 is not tilted. When the operation lever 67 is operated to the up position, the control valve 63 is switched, and hydraulic oil (pressurized oil) is supplied from the hydraulic pump 61 to the hydraulic cylinder 52. The hydraulic cylinder 52 extends as the hydraulic oil is supplied, lifting the cargo box 4. On the other hand, when the operation lever 67 is operated to the down position, the control valve 63 is switched, and the hydraulic oil supplied to the hydraulic cylinder 52 flows back to the hydraulic oil tank 62. Accordingly, the hydraulic cylinder 52 contracts, lowering the cargo box 4.

[0017] The hydraulic mechanism is provided with a pressure gauge 81 for measuring the magnitude of the hydraulic pressure acting on the hydraulic cylinder 52. The specially equipped vehicle 1 is also provided 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.

[0018] 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 longitudinal and lateral directions). The inclinometer 82 measures the longitudinal tilt (pitch) and lateral tilt (roll) of the truck chassis 2 relative to the direction of gravity (vertical direction) over time and outputs measurement data related to the measured tilt. The inclinometer 83 is attached to an appropriate location on the cargo box 4 and measures the longitudinal tilt (pitch) and lateral tilt (roll) of the cargo box 4 relative to the direction of gravity (vertical direction) over time and outputs measurement data related to the measured tilt. The dump angle of the cargo box 4 relative to the truck chassis 2 is calculated by taking the difference between the measurement values ​​of the inclinometer 83 and the inclinometer 82.

[0019] The specially equipped vehicle 1 is equipped with an estimation device 100 that estimates the weight of a load (load weight) based on data obtained from a pressure gauge 81 and an inclinometer 82. In this embodiment, the load weight represents the weight of the load loaded in the cargo box 4 and does not include the weight of the occupants aboard the specially equipped vehicle 1, the fuel loaded in the specially equipped vehicle 1, the running parts and mounting devices that constitute the specially equipped vehicle 1, etc. It is assumed that the weights of the running parts and mounting devices when the specially equipped vehicle 1 is unloaded are known. The internal configuration of the estimation device 100 and the processing executed by the estimation device 100 will be described in detail later. In this embodiment, the load weight of the specially equipped vehicle 1 is estimated using the relationship between data including data on the magnitude of hydraulic pressure obtained from the pressure gauge 81 (first data), data on the tilt angle obtained from the inclinometer 82 (second data), and the load weight. The estimation device 100 is provided, for example, inside the cab 20. Alternatively, the estimation device 100 may be attached to the chassis frame 21.

[0020] In this embodiment, a dump truck equipped with a dump device 3 will be described as an example of a specially equipped vehicle 1, but the specially equipped vehicle 1 is not limited to a dump truck and may be any specially equipped vehicle equipped with a dump device having a hydraulic cylinder, such as a dump discharge suction vehicle or a dump discharge garbage collection vehicle.

[0021] The configuration of the loaded weight estimation system according to this embodiment will be described below. 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 specially equipped vehicle 1 based on hydraulic pressure data that has been corrected for hydraulic pressure decline over time, and a display device 120 that notifies information related to the load weight estimated by the estimation device 100.

[0022] The estimation device 100 is a dedicated or general-purpose computer, and includes 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.

[0023] The control unit 101 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The ROM included in the control unit 101 stores a control program that controls the operation of each hardware unit included in the estimating device 100. The CPU in the control unit 101 executes the control program stored in the ROM and various computer programs stored in a storage unit 102 (described later) to control the operation of each hardware unit, thereby realizing the functions of the estimating device 100 in this embodiment. The RAM included in the control unit 101 temporarily stores data used during execution of calculations, etc.

[0024] The control unit 101 may be equipped with functions such as a clock that outputs date and time information, a timer that measures the elapsed time from when an instruction to start measurement is given until when an instruction to end measurement is given, and a counter that counts numbers.

[0025] The storage unit 102 includes a storage device using a hard disk, a flash memory, etc. The storage unit 102 stores computer programs executed by the control unit 101, various data acquired from the outside, various data generated inside the estimating device 100, etc.

[0026] The computer programs stored in the storage unit 102 include an estimation program PG1 for calibrating data relating to the magnitude of the hydraulic pressure obtained from the pressure gauge 81 and estimating the load weight of the specially equipped vehicle 1 based on the calibrated data.

[0027] The computer programs stored in the storage unit 102 are provided, for example, by a non-transitory storage medium RM1 on which the computer programs are readably recorded. The storage medium RM1 is, for example, a portable memory such as a CD-ROM, a USB memory, or an SD (Secure Digital) card. The control unit 101 reads various programs from the storage medium RM1 using a reading device (not shown) and stores the read programs in the storage unit 102. The computer programs stored in the storage unit 102 may also 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.

[0028] The storage unit 102 also stores calibration data CD1 used to calibrate the magnitude of the oil pressure obtained from the pressure gauge 81. Specifically, the calibration data CD1 is an offset value for the magnitude of the oil pressure. In this embodiment, the offset value is subtracted from the magnitude of the oil pressure obtained from the pressure gauge 81 to perform zero point adjustment of the load weight.

[0029] The memory unit 102 also has a relationship table TB1 that defines the relationship between data related to the magnitude of the hydraulic pressure after calibration (first data), data related to the tilt angle of the truck chassis 2 obtained from the inclinometer 82 (second data), and data including the load weight. The data related to the tilt angle of the truck chassis 2 obtained from the inclinometer 82 (second data) can be considered as data on the tilt angle of the entire vehicle, i.e., the specially equipped vehicle 1. The configuration of the relationship table TB1 will be described in detail later. The first data defined in the relationship table TB1 may be data on the hydraulic pressure value, or may be data on a converted weight obtained by converting the hydraulic pressure value into a loaded weight according to a predetermined relational expression. The relational expression used for the conversion may be prepared according to the type of the specially equipped vehicle 1 and the hydraulic cylinder 52.

[0030] The operation unit 103 is configured with switches, buttons, etc., and accepts various operations. The control unit 101 executes appropriate processing based on the operations accepted through the operation unit 103. Note that, in this embodiment, the estimation device 100 is configured to include the operation unit 103, but the operation unit 103 is not essential, and the operation may be accepted via an externally connected device or the communication unit 106.

[0031] The input unit 104 has an interface for connecting various sensors, and is connected to sensors such as a pressure gauge 81 and inclinometers 82 and 83. These sensors may be connected to the input unit 104 by wire or wirelessly. Measurement data relating to the cylinder pressure of the hydraulic cylinder 52 output from the pressure gauge 81, measurement data relating to the inclination of the specially equipped vehicle 1 output from the inclinometer 82, measurement data relating 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 includes an output interface for connecting a display device 120 such as a liquid crystal monitor. The display device 120 is provided, for example, near the driver's seat of the cab 20. Alternatively, the display device 120 may be provided on the rear side of the front panel 41. The output interface provided in the output unit 105 may be an output interface that outputs an analog video signal, or an output interface that outputs a digital video signal such as DVI (Digital Visual Interface) or HDMI (High-Definition Multimedia Interface, registered trademark). The output unit 105 outputs display data to the display device 120 so that the estimated load weight is displayed on the display device 120, for example.

[0033] In this embodiment, the display device 120 is connected to the outside of the estimation device 100, but the estimation device 100 may include the display device 120 mounted thereon.

[0034] The communication unit 106 includes a communication interface for transmitting and receiving various data to and from external devices. Examples of devices with which the estimating device 100 communicates via the communication unit 106 include various ECUs (Electronic Controller Units) and PLCs (Programmable Logic Controllers) mounted on the specially equipped vehicle 1. In this case, the communication unit 106 may include, for example, a communication port conforming to RS-485, or a communication interface conforming to 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 specially equipped vehicle 1. Other examples of devices with which the estimating device 100 communicates via the communication unit 106 include a server device installed outside the specially equipped vehicle 1 and a mobile terminal carried by the user. In this case, the communication unit 106 may include a communication interface conforming to a wireless communication standard such as WiFi (registered trademark), 3G, 4G, 5G, or LTE (Long Term Evolution), in order to communicate with an external server device or the like.

[0035] While the loading work into the cargo box 4 is being carried out, the estimation device 100 constantly acquires data on the magnitude of the oil pressure from the pressure gauge 81 and estimates the load weight in real time based on the acquired data. However, if the zero point of the load weight fluctuates due to aging, temperature changes, etc., it is not possible to obtain an accurate load weight.

[0036] Therefore, the estimation device 100 according to this embodiment automatically performs zero-point adjustment of the loaded weight when estimating the loaded weight. Fig. 5 is a flowchart illustrating the procedure for estimating the loaded weight according to the first embodiment. The control unit 101 of the estimation device 100 reads out and executes the estimation program PG1 from the storage unit 102, thereby performing the following processing.

[0037] The control unit 101 determines whether the current mode is the weighing mode (step S101). For example, the control unit 101 determines whether the weighing switch 89 is on, and if it determines that the weighing switch 89 is on, it determines that the current mode is the weighing mode. If it determines that the current mode is not the weighing mode (S101: NO), the control unit 101 waits until the current mode is the weighing mode.

[0038] If it is determined that the current mode is the weighing mode (S101: YES), the control unit 101 acquires data on the magnitude of oil pressure output in chronological order from the pressure gauge 81, and data on the tilt angle of the special vehicle 1 output in chronological order from the inclinometer 82, etc., through the input unit 104 (step S102).

[0039] Next, the control unit 101 determines whether the specially equipped vehicle 1 is in a stable stopped state based on the acquired data (step S103). The control unit 101 can determine whether the specially equipped vehicle 1 is in a stable stopped state based on the magnitude of temporal fluctuations in the pitch angle, roll angle, dump angle, and hydraulic pressure of the specially equipped vehicle 1. For example, when the pitch angle of the specially equipped vehicle 1 is θp, the roll angle of the specially equipped vehicle 1 is θr, the dump angle is θd, and the hydraulic pressure of the hydraulic cylinder 52 measured by the pressure gauge 81 is P1, if |Δθp|, |Δθr|, and |Δθd| are each less than 0.1 degrees and |ΔP1| is less than 0.05 MPa, the specially equipped vehicle 1 can be determined to be in a stable stopped state. Here, Δθp, Δθr, Δθd, and ΔP1 represent changes in the pitch angle, roll angle, dump angle, and hydraulic pressure within a set period. The dump angle θd is an angle calculated by subtracting the tilt angle of the truck chassis 2 (the value measured in the pitch direction by the inclinometer 82) from the tilt angle of the cargo box 4 (the value measured in the pitch direction by the inclinometer 83). The threshold values ​​for the angle used for judgment and the time fluctuation of the hydraulic value are set appropriately depending on the vehicle type, etc.

[0040] If it is determined in step S103 that the vehicle is in a stable stopped state (S103: YES), the control unit 101 determines whether the cargo box 4 has been manually or automatically adjusted to within a predetermined angle range (step S104). For example, it determines whether the dump angle θd is greater than 0.5 degrees and less than 1.5 degrees. If the dump angle θd is greater than 0.5 degrees and less than 1.5 degrees, the cargo box 4 has been tilted from the traveling state (lying state) to a dump angle suitable for weighing. If it is determined that the dump angle is within the predetermined angle range (S104: YES), the process proceeds to step S105.

[0041] Next, the control unit 101 determines whether the specially equipped vehicle 1 is within the update range based on whether the pitch angle, roll angle, and hydraulic pressure value are within the set range (step S105). For example, if |θp| is less than 0.8 degrees, |θr| is less than 2 degrees, and |P1-P0| is less than 0.5 MPa, it can be determined that the specially equipped vehicle 1 is within the update range. Here, P0 is an offset value for the hydraulic pressure value P1 and represents the calibration data CD1 stored in the memory unit 102. The threshold values ​​for the angle and hydraulic pressure used for the determination are values ​​beyond which it can be determined that the posture of the specially equipped vehicle 1 is unsuitable for updating the offset value P0 or that a load has already been loaded, making it unsuitable for updating the offset value P0, and are set appropriately depending on the vehicle model, etc. If the posture is within the update range, the posture of the specially equipped vehicle 1 remains approximately horizontal, and no load is loaded in the cargo box 4.

[0042] If it is determined in step S105 that the offset value P0 is within the update range (S105: YES), the control unit 101 updates the offset value P0 (step S106). The control unit 101 calculates the offset value P0' to be applied at the current timing based on the magnitude (actual measured value) P1 of the hydraulic pressure when the cargo box 4 is at a predetermined dump angle and no cargo is loaded in the cargo box 4, and the offset value P0 calculated at the previous timing. For example, the control unit 101 calculates the offset value P0' to be applied at the current timing by calculating f1 × P0 + f2 × P1. Here, f1 and f2 are weighting coefficients, and are set so that the sum of these coefficients equals 1, for example, f1 = 0.995 and f2 = 0.005. These weighting coefficients f1 and f2 are set to reduce the influence of sudden, extreme changes in the hydraulic pressure value due to noise. The control unit 101 updates the offset value by rewriting the calibration data CD1 (offset value P0 calculated at the previous timing) stored in the storage unit 102 with the newly calculated offset value P0'. Once the offset value has been updated in step S106, the process proceeds to step S107.

[0043] Once the offset value is updated in step S106, the control unit 101 calibrates the measured oil pressure by referring to the calibration data CD1 stored in the memory unit 102 (step S107). Specifically, the control unit 101 calculates the calibrated oil pressure P2' by subtracting the offset value P0' stored as the calibration data CD1 from the oil pressure P1 acquired in step S102 and falling within the update range of step S105. In other words, P2' = P1 - P0'. Rather than directly using the oil pressure value P1 of the pressure gauge 81 to estimate the load weight, the calibrated oil pressure value P2', which is the difference between P1 and P0', is used to estimate the load weight, thereby reducing the influence of changes in temperature, etc.

[0044] On the other hand, if it is determined in step S103 that the specially equipped vehicle 1 is not in a stable stopped state (S103: NO), if it is determined in step S104 that the dump angle θd is not within the predetermined angle range (S104: NO), or if it is determined in step S105 that the dump angle θd is not within the update range (S105: NO), the offset value is not updated, and processing from step S107 onwards is executed. The calibration data CD1 stored in the memory unit 102 remains the offset value P0 calculated at the previous timing. In this case, the control unit 101 calculates the magnitude P2 of the calibrated hydraulic pressure by subtracting the offset value P0 calculated at the previous timing from the magnitude P1 of the hydraulic pressure acquired in step S102. In other words, P2 = P1 - P0. In other words, the offset value is automatically updated only when the specially equipped vehicle 1 is in a state suitable for updating.

[0045] Next, the control unit 101 estimates the load weight in the container 4 based on the magnitude of the calibrated hydraulic pressure (step S108). The method of estimating the load weight will be described in detail later.

[0046] The control unit 101 notifies the user of the estimated load weight (step S109). At this time, the control unit 101 outputs information about the estimated load weight from the output unit 105 and displays it on the display device 120. FIG. 6 is a schematic diagram showing an example of a display of the load weight. FIG. 6 shows an example in which the estimated value of the load weight, the load ratio, and information about the estimated date and time are displayed as text information on the display device 120. Here, the estimated value of the load weight is the value of the load weight estimated by referring to the relationship table TB1. The load ratio is a value calculated as the ratio of the load weight (estimated value) to the upper limit value. 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 display screen data based on the estimated load weight estimated by referring to the relationship table TB1, the loading rate calculated as a percentage of the upper limit, and the date and time information obtained from the built-in clock, and outputs the generated display screen data to the display device 120, thereby causing the display device 120 to display a screen such as that shown in Figure 6.

[0047] Next, the control unit 101 determines whether the loading operation has been completed (step S110). For example, the control unit 101 determines whether the weighing switch 89 has been turned off, and if it determines that the weighing switch 89 has been turned off, it determines that the loading operation has been completed (S110: YES). On the other hand, if the control unit 101 determines that the loading operation has not been completed (S110: NO), it returns the process to step S102. The processes from step S102 to step S110 are repeated until it is determined that the loading operation has been completed.

[0048] Next, a method for estimating the load weight will be described. The estimation device 100 according to this embodiment estimates the load weight in the cargo box 4 based on the calibrated hydraulic pressure value. Any estimation method that uses data related to the magnitude of hydraulic pressure can be adopted. As an example, a method of estimating the load weight using a relationship table TB1 that stores the relationship between data including data related to the magnitude of hydraulic pressure (hereinafter referred to as first data), data related to the tilt angle of the specially equipped vehicle 1 (hereinafter referred to as second data), and the load weight in the cargo box 4 will be described below.

[0049] FIG. 7 is a conceptual diagram showing an example of the configuration of the relationship table TB1 in the first embodiment. The relationship table TB1 stores the converted weight (i_weight) obtained from the hydraulic pressure value, the tilt angle (pitch, roll) of the specially equipped vehicle 1, and the loaded weight (a_weight) in association with each other. Here, the converted weight and tilt angle are input values, and represent first data (data related to the magnitude of hydraulic pressure) and second data (data related to the tilt angle), respectively. On the other hand, the loaded weight is an output value when an input value is given, and represents an estimated value of the loaded weight in the shipping box 4. Note that the first data shown in the relationship table TB1 in FIG. 7 is converted weight data obtained by converting the calibrated hydraulic pressure value into the loaded weight according to a predetermined relational expression, but it may also be data of the calibrated hydraulic pressure value itself. The relational expression used for the conversion may be prepared according to the type of the specially equipped vehicle 1 and the hydraulic cylinder 52.

[0050] In the first embodiment, the relationship table TB1 stores values ​​in the range of 3.0 to 12.9 tons in increments of 0.1 tons as the converted weight (i_weight), values ​​in the range of -8 to 8 degrees in increments of 1 degree as the pitch angle (Pitch), and values ​​in the range of 0 to 4 degrees in increments of 1 degree as the roll angle (Roll). Note that, since the roll angle has a nearly symmetrical characteristic, absolute values ​​can be used. However, there are cases where the characteristic is not symmetrical, and in such cases, values ​​of the pitch angle and converted weight may be set for each of the left and right roll angle values.

[0051] The above-mentioned input values ​​and output values ​​(estimated values) are converted into an address map and stored inside 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 relationship table TB1. The control unit 101 estimates the load weight of the shipping box 4 based on the value read from the relationship table TB1.

[0052] Fig. 8 is an explanatory diagram for explaining how to calculate the loaded weight when input values ​​are given. Taking as an example the case where the input values ​​are converted weight: 8.55 tons, pitch angle: 5.5 degrees, and roll angle: 2.5 degrees, the method for calculating the loaded weight will be explained. Assuming a three-dimensional space with the converted weight, pitch angle, and roll angle as the coordinate axes, the point determined when the converted weight (i_weight) and tilt angle (Pitch, Roll) stored in relational table TB1 are specified (when an address is specified) represents a lattice point in the three-dimensional space.

[0053] The points representing the input values ​​(points indicated by stars in the figure) do not coincide with any lattice points and are contained within a rectangular parallelepiped having eight lattice points LP1 to LP8 as vertices, as shown in FIG. 8. In this case, the control unit 101 specifies the eight lattice points LP1 to LP8 (addresses) surrounding the points representing the input values, and reads out the values ​​of the load weight (a_weight) stored in association with each of the lattice points LP1 to LP8 (addresses) from the relationship table TB1. For example, when the address corresponding to the lattice point LP1 (equivalent weight: 8.5 tons, pitch angle: 5 degrees, roll angle: 2 degrees) is specified, a value of 8.9 tons can be read out as the load weight (a_weight). The same applies when addresses corresponding to the other lattice points LP2 to LP8 are specified.

[0054] The control unit 101 first calculates the interval value in the i_weight direction based on the values ​​read from the lattice points LP1 to LP8. For example, the control unit 101 calculates (9.0-8.9) x (8.55-8.5) / 0.1+8.9=8.95 as the interval value for LP1-LP2, and (9.1-9.0) x (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.

[0055] Next, the control unit 101 calculates the section value in the Pitch direction based on the calculated section value in the i_weight direction. For example, the control unit 101 calculates (9.05-8.95) x (5.5-5) / 1 + 8.95 = 9.00 as the section value for LP1, LP2-LP3, and LP4, and (9.05-8.95) x (5.5-5) / 1 + 8.95 = 9.00 as the section value for LP5, LP6-LP7, and LP8.

[0056] Finally, the control unit 101 calculates the section value in the roll direction based on the calculated section value in the pitch direction. For example, the control unit 101 calculates (9.00-8.00) x (2.5-2) / 1 + 9.00 = 9.00 as the section value for L1, L2, L3, L4-L5, L6, L7, and L8.

[0057] Through the above calculations, the control unit 101 obtains an estimated value of 9.00 tons as the loaded weight when the input values ​​are converted weight: 8.55 tons, pitch angle: 5.5 degrees, and roll angle: 2.5 degrees.

[0058] In this embodiment, the procedure is to calculate the section values ​​in the i_weight direction, pitch direction, and roll direction in this order, but the order in which the section values ​​are calculated is not limited to the above and can be set as appropriate.

[0059] As described above, in this embodiment, the load weight is estimated based on data related to the hydraulic pressure after correcting for the decrease in hydraulic pressure that occurs over time, so that the load weight can be estimated more accurately even if time has passed due to loading work, etc.

[0060] In this embodiment, the load weight is estimated using a relationship table TB1 that defines the relationship between data on the magnitude of hydraulic pressure (data on converted weight), data on the tilt angle of the specially equipped vehicle 1, and the load weight, but the relationship table TB1 may define only the relationship between data on the magnitude of hydraulic pressure (data on hydraulic pressure value or converted weight) and the load weight. Also, instead of using the relationship table TB1 to estimate the load weight, the load weight may be estimated using a function or learning model that defines the relationship between data including the hydraulic pressure value and the load weight.

[0061] Furthermore, in the relationship table TB1 shown in Fig. 7, data is prepared in increments of 0.1 ton across the entire range of load weight (3 to 13 tons in the example of Fig. 7), but the granularity of the data may be set so that the data is dense near the maximum load weight of the specially equipped vehicle 1 and sparse in other ranges. For example, if the maximum load weight is 10 tons, the resolution may be 0.01 ton in the range of 9.00 to 10.99 tons, and 0.1 ton in other ranges.

[0062] As described above, in this embodiment, data regarding the magnitude of oil pressure is calibrated at a timing before the load weight is estimated, so that the load weight can be accurately estimated even if the zero point of the load weight fluctuates due to changes over time or temperature changes, etc.

[0063] (Embodiment 2) In the second embodiment, a configuration will be described in which the loaded weight is estimated by distinguishing between a state in which the container 4 is stopped after being raised and a state in which the container 4 is stopped after being lowered.

[0064] The inventors of the present application have investigated in detail the relationship between the pitch angle of the truck chassis 2 and the hydraulic pressure value, and have found that there is a difference between the hydraulic pressure value when the cargo box 4 is stopped after being raised and the hydraulic pressure value when the cargo box 4 is stopped after being lowered. Therefore, the load weight estimation system in the second embodiment distinguishes between the state when the cargo box 4 is stopped after being raised and the state when the cargo box 4 is stopped after being lowered, and estimates the load weight using different relationship tables for both states.

[0065] 9 is a block diagram illustrating the configuration of a loaded weight estimation system according to the second embodiment. The estimation device 100 includes 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 units is the same as that described in the first embodiment, and therefore a description thereof will be omitted.

[0066] The storage unit 102 includes a relationship table TB10 for stopping ascent and a relationship table TB20 for stopping descent. The relationship table TB10 for stopping ascent defines the relationship between the loaded weight and data on the converted weight (i_weight) and tilt angle (pitch, roll) acquired when the container 4 has stopped after ascending. The relationship table TB20 for stopping descent defines the relationship between the loaded weight and data on the converted weight (i_weight) and tilt angle (pitch, roll) acquired when the container 4 has stopped after descending. The relationship tables TB10 and TB20 may be tables with constant resolution over the entire range, or may be tables with improved resolution in a range near the maximum loaded weight.

[0067] 10 is a flowchart illustrating the procedure for estimating the load weight in embodiment 2. The control unit 101 of the estimation device 100 determines whether the metering switch 89 is turned on by monitoring a signal input through the input unit 104 (step S201). If the metering switch 89 is not turned on (S201: NO), the control unit 101 waits until the metering switch 89 is turned on.

[0068] When the weighing switch 89 is turned on (S201: YES), the control unit 101 starts the load weight estimation process. When the estimation process starts, 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 in the range of more than 0.5 degrees and less than 1.5 degrees. The control unit 101 may instruct the user by displaying text information on the display device 120, or by outputting audio from a speaker (not shown). In the second embodiment, the dump angle is manually adjusted using the operating lever 67.

[0069] The control unit 101 sequentially acquires measurement data of the tilt angle measured in time series by the inclinometers 82 and 83 via the input unit 104, and detects the current dump angle based on the acquired measurement data (step S202). The control unit 101 can obtain the dump angle by subtracting the tilt angle of the truck chassis 2 obtained as the measurement value of the inclinometer 82 from the tilt angle of the cargo box 4 obtained as the measurement value of the inclinometer 83. The control unit 101 stores the detected dump angles in time series in the memory unit 102.

[0070] The control unit 101 determines whether the dump angle detected in step S202 is greater than a minimum angle θ1 (step S203). The minimum angle θ1 is a value set as the minimum value of an angle range suitable for measuring the load weight of the cargo box 4. An example of the minimum angle θ1 is 0.5 degrees.

[0071] If it is determined that the current dump angle is equal to or less than the minimum angle θ1 (S203: NO), the control unit 101 instructs the user to raise the cargo box 4 (step S204). The control unit 101 instructs the user by displaying text information on the display device 120 that indicates that the cargo box 4 should be raised. Alternatively, the control unit 101 may instruct the user by outputting a voice message from a speaker (not shown) that indicates that the cargo box 4 should be raised. The user who receives the instruction operates the operating lever 67 to raise the cargo box 4 by an appropriate angle and then stop the operation. After instructing the user, the control unit 101 returns the process to step S202.

[0072] If it is determined that the current dump angle is greater than the minimum angle θ1 (S203: YES), the control unit 101 determines whether the current dump angle is less than the maximum angle θ2 (step S205). The maximum angle θ2 is a value 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.

[0073] If it is determined that the current dump angle is equal to or greater than the maximum angle θ2 (S205: NO), the control unit 101 instructs the user to lower the cargo box 4 (step S206). The control unit 101 instructs the user, for example, by displaying text information on the display device 120 instructing the user to lower the cargo box 4. Alternatively, the control unit 101 may instruct the user by outputting a voice message instructing the user to lower the cargo box 4 from a speaker (not shown). The user who receives the instruction operates the operating lever 67 to lower the cargo box 4 by an appropriate angle and stop it. After instructing the user, the control unit 101 returns the process to step S202.

[0074] If it is determined that the current dump angle is smaller than the maximum angle θ2 (S205: YES), the control unit 101 refers to the output of the built-in timer and determines whether a predetermined time has elapsed since the dump angle entered the set angle range (step S207). If the predetermined time has not elapsed (S207: NO), the control unit 101 waits until the predetermined time has elapsed.

[0075] If it is determined that the predetermined time has elapsed (S207: YES), the control unit 101 determines whether the cargo box 4 was in a stationary state until the predetermined time elapsed (step S208). The control unit 101 can determine whether the cargo box 4 was in a stationary state by determining whether there has been a change in the dump angle from the historical data stored in the memory unit 102. If the cargo box 4 was not in a stationary state (S208: NO), the control unit 101 returns the process to step S202.

[0076] If the container 4 remains stationary until the predetermined time has elapsed (S208: YES), the control unit 101 determines whether the container 4 has stopped after being lifted (step S209). The control unit 101 can determine whether the container 4 has stopped after being lifted from the dump angle history data stored in the memory unit 102.

[0077] When the control unit 101 determines that the container 4 has stopped after ascending (S209: YES), it selects the relationship table TB10 for ascending stop as a table to be referenced when estimating the load weight (step S210). On the other hand, when the control unit 101 determines that the container 4 has stopped after descending (S209: NO), it selects the relationship table TB20 for descending stop as a table to be referenced when estimating the load weight (step S211).

[0078] Next, the control unit 101 notifies the user that the load weight is ready to be measured (step S212). For example, the control unit 101 causes the display device 120 to display text information indicating that the load weight is ready to be measured. Alternatively, the control unit 101 may cause a speaker (not shown) to output a sound indicating that the load weight is ready to be measured.

[0079] After the weighing preparation is completed, the control unit 101 acquires data on the magnitude of oil pressure output in chronological order from the pressure gauge 81, and data on the inclination angle of the special vehicle 1 output in chronological order from the inclinometer 82, etc., through the input unit 104 (step S213).

[0080] The control unit 101 executes a hydraulic pressure calibration process based on the acquired data (step S214). Specifically, the control unit 101 executes the processes from steps S103 to S107 in the flowchart shown in FIG. 5. That is, the control unit 101 sequentially updates the offset value while the specially equipped vehicle 1 is in a stable stopped state, the dump angle is within a predetermined angle range, and the acquired data is within the update range. When loading work is started, the hydraulic pressure value falls outside the update range, so the magnitude of the hydraulic pressure can be calibrated based on the offset value stored at that time.

[0081] Next, the control unit 101 estimates the load weight in the shipping box 4 by referring to the relationship table TB1 (step S215). The control unit 101 acquires converted weight data from the calibrated hydraulic pressure value, and uses the acquired converted weight data (first data) and the data on the tilt angle of the specially equipped vehicle 1 (second data) as input values, and reads out an output value from the relationship table TB1, thereby estimating the load weight.

[0082] The control unit 101 notifies the estimated loaded weight (step S216). At this time, the control unit 101 outputs information on the estimated loaded weight from the output unit 105 and causes the display device 120 to display it.

[0083] In the second embodiment, a distinction is made between a state in which the cargo box 4 is stopped after being raised and a state in which the cargo box 4 is stopped after being lowered, and different relationship tables are used to estimate the load weight for both states, thereby minimizing the decline in estimation accuracy compared to when a common table is used for estimation for both states.

[0084] (Embodiment 3) In the third embodiment, a configuration for automatically performing the lift stop operation will be described.

[0085] 11 is a block diagram illustrating the configuration of a loaded weight estimation system according to the third embodiment. The loaded weight estimation system according to the third embodiment includes an estimation device 100 and a lifting / lowering control device 200 connected to the estimation device 100. The estimation device 100 is similar to that described in the second embodiment, and includes 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. Note that in the third embodiment, only the relationship table TB10 for stopping ascent is used, and therefore the relationship table TB20 for stopping descent does not need to be stored in the storage unit 102.

[0086] The lifting control device 200 includes an input unit 201, a control unit 202, and an output unit 203, and controls the operation of the hydraulic mechanism included in the specially equipped vehicle 1 to control the lifting and lowering of the cargo box 4. The input unit 201 includes an input interface. Information output from the estimation device 100, operation information of the operating lever 67, operation information of the PTO switch 72, etc. are input to the input unit 201. The information input to the input unit 201 is output to the control unit 202.

[0087] The control unit 202 is configured by, for example, a PLC (Programmable Logic Controller). The control unit 202 generates a control signal for controlling the lifting and lowering of the container 4 based on information input through the input unit 201 in accordance with programmed logic. The control unit 202 outputs the generated control signal to the control valve 63 from the output unit 203. The output unit 203 has an output interface, and is connected to the control valve 63, the estimation device 100, and the like. Note that the control valve 63 in the third embodiment is configured as an electrically controllable electromagnetic control valve.

[0088] In this embodiment, the load weight estimation system is configured to include the estimation device 100 and the lifting control device 200 as separate entities, but the two may also be configured as an integrated unit.

[0089] 12 is a flowchart illustrating the procedure for estimating a load weight in embodiment 3. The control unit 101 of the estimation device 100 determines whether the metering switch 89 is turned on by monitoring a signal input through the input unit 104 (step S301). If the metering switch 89 is not turned on (S301: NO), the control unit 101 waits until the metering switch 89 is turned on.

[0090] If the metering switch 89 is turned on (S301: YES), the control unit 101 determines whether the PTO switch 72 is on or not (step S302). If the PTO switch 72 is not on (S302: NO), the control unit 101 instructs the user to turn on the PTO switch 72 (step S303) 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 may be given by outputting audio from a speaker (not shown).

[0091] If the PTO switch 72 is on (S302: YES), the control unit 101 notifies the user that the dump angle should be adjusted (step S304). For example, the control unit 101 causes the display device 120 to display text information indicating that the dump angle should be adjusted. Alternatively, the control unit 101 may cause a speaker (not shown) to output a sound indicating that the dump angle should be adjusted.

[0092] Next, the control unit 101 instructs the lifting / lowering control device 200 to lift the packing box 4 (step S305). Specifically, the control unit 101 generates a control signal instructing the lifting / lowering control device 200 to lift the packing box 4, and outputs the generated control signal to the lifting / lowering control device 200 from the output unit 105, thereby issuing an instruction to the lifting / lowering control device 200. In response to the instruction from the estimation device 100, the control unit 202 of the lifting / lowering control device 200 outputs a control signal for lifting the packing box 4 to the control valve 63, thereby lifting the packing box 4.

[0093] The control unit 101 sequentially acquires measurement data of the tilt angle measured in time series by the inclinometers 82 and 83 through the input unit 104, and detects the current dump angle based on the acquired measurement data (step S306).

[0094] The control unit 101 determines whether the dump angle detected in step S306 is greater than the minimum angle θ1 (step S307). 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.

[0095] When it is determined that the current dump angle is equal to or smaller than the minimum angle θ1 (S307: NO), the control unit 101 returns the process to step S305 and continues the control of raising the container 4.

[0096] If it is determined that the current dump angle is greater than the minimum angle θ1 (S307: YES), the control unit 101 determines whether the current dump angle is less than the maximum angle θ2 (step S308). The maximum angle θ2 is a value 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.

[0097] If it is determined that the current dump angle is equal to or greater than the maximum angle θ2 (S308: NO), the control unit 101 issues an error notification (step S309) because the tilt angle of the cargo box 4 is outside the angle range suitable for measuring the load weight, and ends the processing according to this flowchart. After notifying the error, the control unit 101 may instruct the lifting control device 200 to lower the cargo box 4.

[0098] If it is determined that the current dump angle is smaller than the maximum angle θ2 (S308: YES), the control unit 101 instructs the loading box 4 to be stopped after being lifted (step S310). Specifically, the control unit 101 generates a control signal instructing the loading box 4 to be stopped, and outputs the generated control signal to the lifting control device 200 from the output unit 105, thereby instructing the lifting control device 200. In response to the instruction from the estimation device 100, the control unit 202 of the lifting control device 200 outputs a control signal for stopping the loading box 4 to the control valve 63, thereby stopping the loading box 4.

[0099] Next, the control unit 101 sets the relational table TB10 for stopping lifting as a table to be referred to when estimating the load weight (step S311), and notifies the user that preparations for weighing the load weight are complete (step S312). The control unit 101, for example, causes the display device 120 to display text information indicating that preparations for weighing the load weight are complete. Alternatively, the control unit 101 may cause a speaker (not shown) to output audio information indicating that preparations for weighing the load weight are complete.

[0100] After the weighing preparation is completed, the control unit 101 acquires data on the magnitude of oil pressure output in chronological order from the pressure gauge 81, and data on the inclination angle of the special vehicle 1 output in chronological order from the inclinometer 82, etc., through the input unit 104 (step S313).

[0101] The control unit 101 executes a hydraulic pressure calibration process based on the acquired data (step S314). Specifically, the control unit 101 executes the processes from steps S103 to S107 in the flowchart shown in FIG. 5. That is, the control unit 101 sequentially updates the offset value while the specially equipped vehicle 1 is in a stable stopped state, the dump angle is within a predetermined angle range, and the acquired data is within the update range. When loading work begins, the hydraulic pressure value falls outside the update range, so the magnitude of the hydraulic pressure can be calibrated based on the offset value stored at that time.

[0102] Next, the control unit 101 estimates the load weight in the shipping box 4 by referring to the relationship table TB1 (step S315). The control unit 101 acquires converted weight data from the calibrated hydraulic pressure value, and uses the acquired converted weight data (first data) and the data on the tilt angle of the specially equipped vehicle 1 (second data) as input values, and reads out an output value from the relationship table TB1, thereby estimating the load weight.

[0103] The control unit 101 notifies the estimated loaded weight (step S316). At this time, the control unit 101 outputs information on the estimated loaded weight from the output unit 105 and causes the display device 120 to display it.

[0104] The control unit 101 may estimate the load weight, notify the user, and then instruct the lifting / lowering control device 200 to lower the container 4. In response to the instruction from the estimation device 100, the control unit 202 of the lifting / lowering control device 200 may lower the container 4 by outputting a control signal for lowering the container 4 to the control valve 63.

[0105] When measuring the load weight manually, the dump angle needs to be adjusted 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 measured automatically by operating the weighing switch 89, which reduces the cumbersomeness of the operation.

[0106] (Fourth embodiment) In the fourth embodiment, a configuration is described in which the load weight is estimated using a common relationship table TB30 when the cargo box 4 is raised and then stopped, and when the cargo box 4 is lowered and then stopped.

[0107] 13 is a block diagram illustrating the configuration of a loaded weight estimation system according to the fourth embodiment. The estimation device 100 includes 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 units is the same as that described in the first embodiment, and therefore a description thereof will be omitted.

[0108] The storage unit 102 has a relationship table TB30 that is common to both the case where the container 4 is raised and then stopped, and the case where the container 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 the first embodiment, and defines the relationship between the converted weight (i_weight) and tilt angle (pitch, roll) data and the load weight. The relationship table TB30 may be a table with constant resolution over the entire range, or may be a table with improved resolution in the range near the maximum load weight.

[0109] In the fourth embodiment, the control unit 101 performs preprocessing for estimating the load weight using the relational table TB30. When the container 4 is stopped after being raised, the control unit 101 converts the calibrated hydraulic pressure value into a converted weight using a relational expression for stopping the ascent (first relational expression). When the container 4 is stopped after being lowered, the control unit 101 converts the calibrated hydraulic pressure value into a converted weight using a relational expression for stopping the descent (second relational expression). These relational expressions have function forms that are determined in advance so that, under the same measurement conditions, the converted weight converted from the hydraulic pressure value (calibrated) after the ascent is stopped and the converted weight converted from the hydraulic pressure value (calibrated) after the descent is stopped are the same. Each relational expression is stored in the storage unit 102. When the control unit 101 acquires the hydraulic pressure value after the ascent is stopped, the control unit 101 performs a hydraulic pressure calibration process, then reads out the relational expression for stopping the ascent from the storage unit 102, and converts the hydraulic pressure value into a converted weight. When the control unit 101 acquires the hydraulic pressure value after the descent is stopped, the control unit 101 performs a hydraulic pressure calibration process, then reads out the relational expression for stopping the descent from the storage unit 102, and converts the hydraulic pressure value into a converted weight. This makes it possible to uniquely calculate the converted weight regardless of whether the lifting or lowering stops. The control unit 101 estimates the loaded weight by referring to the relationship table TB30 based on the converted weight.

[0110] Fig. 14 is a flowchart illustrating the procedure for estimating the load weight in the fourth embodiment. The control unit 101 of the estimation device 100 executes the same procedures as S201 to S208 in the flowchart shown in Fig. 10 (steps S401 to S408), and after completing the weighing preparation, notifies the user that the load weight weighing preparation is complete (step S409). After the weighing preparation is completed, the loading operation is carried out. The control unit 101 constantly acquires first data (oil pressure value) based on the measurement result of the pressure gauge 81 and second data (tilt angle of the specially equipped vehicle 1) based on the measurement result of the inclinometer 82 (step S410).

[0111] The control unit 101 executes a hydraulic pressure calibration process based on the acquired data (step S411). Specifically, the control unit 101 executes the processes from steps S103 to S107 in the flowchart shown in FIG. 5. That is, the control unit 101 sequentially updates the offset value while the specially equipped vehicle 1 is in a stable stopped state, the dump angle is within a predetermined angle range, and the acquired data is within the update range. When loading work is started, the hydraulic pressure value falls outside the update range, so the magnitude of the hydraulic pressure can be calibrated based on the offset value stored at that time.

[0112] After executing the hydraulic pressure calibration process, the control unit 101 determines whether the container 4 has stopped after rising between S401 and S408 (step S412). If the control unit 101 determines that the container 4 has stopped after rising (S412: YES), it reads out the relational equation for stopping the rise from the storage unit 102 and converts the calibrated hydraulic pressure value into a converted weight (step S413). On the other hand, if the control unit 101 determines that the container 4 has stopped after falling (S412: NO), it reads out the relational equation for stopping the descent from the storage unit 102 and converts the calibrated hydraulic pressure value into a converted weight (step S414).

[0113] The control unit 101 estimates the load weight in the shipping box 4 by referring to the relationship table TB30 based on the converted weight converted in step S413 or step S414 (step S415). The method of estimating the load weight using the relationship table TB30 is the same as in the first embodiment.

[0114] Next, the control unit 101 notifies the user of the estimated load weight (step S416). At this time, the control unit 101 outputs information about the estimated load weight 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 may use a schematic display method such as a graph or meter display. The control unit 101 may also be configured to output the estimated load weight information as audio from a speaker (not shown). After this series of processes is completed, the user operates the operating lever 67 to lower the cargo box 4 until the dump angle becomes 0 degrees. Thereafter, the weighing switch 89 is turned off, thereby completing the weighing.

[0115] As described above, in the fourth embodiment, the relational expression for stopping ascent and the relational expression for stopping descent are used together to calculate the converted weight by eliminating the difference between the hydraulic pressure value when ascent is stopped and the hydraulic pressure value when descent is stopped. This eliminates the need to prepare two types of relational tables (a relational table for stopping ascent and a relational table for stopping descent) to estimate the load weight from the converted weight, and makes it possible to estimate the load weight even in an estimation device 100 with a relatively small storage capacity of the memory unit 102.

[0116] (Embodiment 5) In the fifth embodiment, a configuration is described in which the relationship (third relational expression) between the oil pressure value measured and calibrated after the ascent has stopped and the oil pressure value measured and calibrated after the descent has stopped is grasped, and either the oil pressure value after the ascent has stopped or the oil pressure value after the descent has stopped is corrected using the third relational expression.

[0117] The configuration of the estimating device 100 in the fifth embodiment is the same as that described in the fifth embodiment. That is, the estimating device 100 in the fifth embodiment has a relationship table TB30 that is common to both a state in which the packing box 4 is stopped after being raised and a state in which the packing box 4 is stopped after being lowered.

[0118] In the fifth embodiment, it is assumed that the relationship between the hydraulic pressure value measured and calibrated after the ascent of the container 4 has stopped and the hydraulic pressure value measured and calibrated after the descent of the container 4 has stopped is known in advance. For example, if the measurement conditions are the same, it is assumed that there is a relationship of PV1 = PV2 + ΔPV between the hydraulic pressure value PV1 measured and calibrated after the ascent of the container 4 has stopped and the hydraulic pressure value PV2 measured and calibrated after the descent of the container 4 has stopped. ΔPV is the differential pressure between PV1 and PV2, and is assumed to be known in the fifth embodiment. A relational expression (third relational expression) showing this relationship is stored in the memory unit 102.

[0119] When the control unit 101 acquires the hydraulic pressure value PV1 measured and calibrated after the ascent has stopped, it converts the acquired hydraulic pressure value PV1 into an equivalent weight according to a predetermined relational expression, and estimates the load weight based on the converted converted weight by referring to the relational table TB30. On the other hand, when the control unit 101 acquires the hydraulic pressure value PV2 measured and calibrated after the descent has stopped, 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 performs a correction by adding the difference ΔPV to the acquired hydraulic pressure value PV2. The control unit 101 converts the corrected hydraulic pressure value (= PV2 + ΔPV) into an equivalent weight according to the predetermined relational expression, and then estimates the load weight by referring to the relational table TB30.

[0120] FIG. 15 is a flowchart illustrating the procedure for estimating the load weight in the fifth embodiment. The control unit 101 of the estimation device 100 executes the same procedures as S201 to S208 in the flowchart shown in FIG. 10 (steps S501 to S508), and after completing the weighing preparation, notifies the user that the load weight weighing preparation is complete (step S509). After the weighing preparation is completed, the loading operation is carried out. The control unit 101 constantly acquires first data (oil pressure value) based on the measurement result of the pressure gauge 81 and second data (tilt angle of the specially equipped vehicle 1) based on the measurement result of the inclinometer 82 (step S510).

[0121] The control unit 101 executes a hydraulic pressure calibration process based on the acquired data (step S511). Specifically, the control unit 101 executes the processes from steps S103 to S107 in the flowchart shown in FIG. 5. That is, the control unit 101 sequentially updates the offset value while the specially equipped vehicle 1 is in a stable stopped state, the dump angle is within a predetermined angle range, and the acquired data is within the update range. When loading work begins, the hydraulic pressure value falls outside the update range, so the magnitude of the hydraulic pressure can be calibrated based on the offset value stored at that time.

[0122] After executing the hydraulic pressure calibration process, the control unit 101 determines whether the container 4 stopped after rising between S501 and S508 (step S512). If the control unit 101 determines that the container 4 stopped after rising (S512: YES), it converts the hydraulic pressure value P1 after the container 4 stopped rising into a converted weight according to a predetermined relational expression (step S514). On the other hand, if the control unit 101 determines that the container 4 stopped after falling (S512: NO), it adds the differential pressure ΔPV to the hydraulic pressure value P2 after the container 4 stopped falling (step S513). Thereafter, the control unit 101 proceeds to step S514, where it converts the hydraulic pressure value to which the differential pressure has been added (= PV2 + ΔPV) into a converted weight according to a predetermined relational expression (step S514).

[0123] The control unit 101 estimates the load weight in the shipping box 4 by referring to the relationship table TB30 based on the converted weight converted in step S514 (step S515). The method of estimating the load weight using the relationship table TB30 is the same as in the first embodiment.

[0124] Next, the control unit 101 notifies the user of the estimated load weight (step S516). At this time, the control unit 101 outputs information about the estimated load weight 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 may use a schematic display method such as a graph or meter display. The control unit 101 may also be configured to output the estimated load weight information as audio from a speaker (not shown). After this series of processes is completed, the user operates the operating lever 67 to lower the cargo box 4 until the dump angle becomes 0 degrees. Thereafter, the weighing switch 89 is turned off, thereby completing the weighing.

[0125] As described above, in the fifth embodiment, since the relationship between the hydraulic pressure value measured and calibrated after the ascent has stopped and the hydraulic pressure value measured and calibrated after the descent has stopped is understood, for example, the hydraulic pressure value measured and calibrated after the descent has stopped can be corrected to a hydraulic pressure value equivalent to the hydraulic pressure value measured and calibrated under the same conditions after the ascent has stopped. This eliminates the need to prepare two types of relationship tables (a relationship table for the ascent stop and a relationship table for the descent stop) to estimate the load weight from the hydraulic pressure value (converted weight), and makes it possible to estimate the load weight even in an estimation device 100 with a relatively small storage capacity in the memory unit 102.

[0126] In this embodiment, the differential pressure is added to the calibrated hydraulic pressure value obtained after the descent has stopped, but the differential pressure may be subtracted from the calibrated hydraulic pressure value obtained after the ascent has stopped. Furthermore, rather than being limited to adding (or subtracting) the differential pressure, any relational expression may be used to correct either one of the hydraulic pressure values.

[0127] (Embodiment 6) In the sixth embodiment, a method for creating the relationship table TB1 will be described.

[0128] In the sixth embodiment, a configuration for creating a relationship table TB1 in an external server device 500 will be described. Fig. 16 is a block diagram illustrating the configuration of the server device 500 in the sixth embodiment. The server device 500 is a dedicated or general-purpose computer, and includes a control unit 501, a storage unit 502, a communication unit 503, an operation unit 504, and a display unit 505.

[0129] The control unit 501 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The ROM included in the control unit 501 stores a control program that controls the operation of each hardware unit included in the server device 500. The CPU in the control unit 501 executes the control program stored in the ROM and various computer programs stored in a storage unit 502 (described later) to control the operation of each hardware unit, thereby realizing the functions of the server device 500 in this embodiment. The RAM included in the control unit 501 temporarily stores data used during execution of calculations, etc.

[0130] The control unit 501 is configured to include a CPU, a ROM, and a RAM, but may alternatively be one or more arithmetic circuits or control circuits including a GPU (Graphics Processing Unit), an FPGA (Field Programmable Gate Array), a DSP (Digital Signal Processor), a quantum processor, volatile or non-volatile memory, etc. The control unit 501 may also include functions such as a clock that outputs date and time information, a timer that measures the elapsed time from when an instruction to start measurement is given until when an instruction to end measurement is given, and a counter that counts numbers.

[0131] The storage unit 502 includes a storage device using a hard disk, a flash memory, etc. The storage unit 502 stores computer programs executed by the control unit 501, various data acquired from the outside, various data generated inside the server device 500, etc.

[0132] The computer programs stored in the storage unit 502 include a learning program PG2 for generating the learning model LM1. Here, the learning model LM1 is configured to output data related to the load weight when first data (data related to the magnitude of hydraulic pressure including converted weight) and second data (data related to the inclination of the specially equipped vehicle 1) are input. The configuration of the learning model LM1 will be described in detail later.

[0133] These computer programs may be provided by a non-transitory recording medium RM2 on which the computer programs are readably recorded. The recording medium RM2 is, for example, a portable memory such as a CD-ROM, a USB memory, or an SD card. The control unit 501 reads the various programs from the recording medium RM2 using a reading device (not shown) and stores the read programs in the storage unit 502. Alternatively, the computer programs may be provided by communication.

[0134] The communication unit 503 includes a communication interface for connecting to a communication network such as the Internet. The interface included in the communication unit 503 is a communication interface conforming to wireless communication standards such as WiFi (registered trademark), 3G, 4G, 5G, LTE (Long Term Evolution), etc. The communication unit 503 transmits various information to be notified to the outside and receives various information transmitted from the outside to its own device.

[0135] The operation unit 504 is equipped with input devices such as a keyboard and a mouse, and receives input of various 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 necessary.

[0136] The display unit 505 includes a display device such as a liquid crystal display panel or an organic EL display panel, and displays information to be notified to the administrator or the like based on a control signal output from the control unit 501.

[0137] 17 is a schematic diagram illustrating an example of the configuration of learning model LM1. Learning model LM1 in this embodiment is, for example, a support vector regression model, and includes an input layer to 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 outputs from the intermediate layer and outputs the calculation results.

[0138] The input, hidden, and output layers of the learning model LM1 each contain one or more nodes, and the nodes in each layer are connected to the nodes in the previous and next layers with unidirectional connection weights. In a support vector machine that has been nonlinearly extended using the kernel trick, the connection weights from the hidden layer to the output layer are adaptively determined through learning. On the other hand, the connection weights from the input layer to the hidden layer are fixed and are calculated mechanically from the training data.

[0139] The input layer of the learning model LM1 receives first data (data relating to the magnitude of hydraulic pressure including converted weight) and second data (data relating to the inclination of the specially equipped vehicle 1). The data input to the input layer is weighted by connection weights determined using training data and output to the middle layer. The middle layer performs calculations using kernels based on the data input from the input layer. The data calculated in each kernel in the middle layer is weighted by connection weights determined by learning and output to the output layer. The output layer outputs the calculation result relating to the load weight by combining the data input from the middle layer.

[0140] Here, the calculation result output by the output layer may be an estimated value of the load weight, or may be the probability of a certain load weight. In the latter case, the output layer is composed of multiple nodes, and the first node outputs the probability that the load weight is 1 ton, the second node outputs the probability that the load weight is 2 tons, ..., and the Nth node (N is an integer of 2 or more) outputs the probability that the load weight is N tons.

[0141] The server device 500 prepares training data to generate the learning model LM1. FIG. 18 is a conceptual diagram of the training data. The training data includes the tilt angle (pitch angle and roll angle) of the specially equipped vehicle 1 measured with a fixed load weight and a converted weight based on the measured hydraulic pressure value (cylinder pressure) of the hydraulic cylinder 52. In the example of FIG. 18, the training data includes the tilt angle measured under various conditions with a cargo of 3 tons (actual measurement value) loaded in the cargo box 4 of the specially equipped vehicle 1 and the converted weight based on the measured hydraulic pressure value, the tilt angle measured under various conditions with a cargo of 4 tons (actual measurement value) loaded in the cargo box 4 of the specially equipped vehicle 1 and the converted weight based on the measured hydraulic pressure value, and the tilt angle measured under various conditions with a cargo of 5 tons (actual measurement value) loaded in the cargo box 4 of the specially equipped vehicle 1 and the converted weight based on the measured hydraulic pressure value.

[0142] Instead of the above-mentioned actual measurement values, or in addition to the above-mentioned actual measurement values, analysis results of CAE (Computer-Aided Engineering) analysis may be used as training data.

[0143] 19 is a flowchart illustrating a first generation method of the learning model LM1. The control unit 501 of the server device 500 reads out the learning program PG2 from the storage unit 502 and executes it, thereby performing the following processing.

[0144] The control unit 501 selects a set of data from the training data (step S601). The training data includes a series of measurement data measured at the same time and the values ​​of the loaded weight when the measurement data were obtained.

[0145] Next, the control unit 501 inputs the selected training data into the learning model LM1 (step S602) and executes calculations using the learning model LM1 (step S603). That is, the control unit 501 inputs measurement data such as converted weight based on hydraulic pressure values ​​and tilt angle into the nodes that make up the input layer of the learning model LM1, executes calculations using kernels in the middle layer, and outputs the calculation results from the output layer. Note that in the initial stage before learning begins, initial values ​​are assigned to the definition information that describes the learning model LM1.

[0146] Next, the control unit 501 evaluates the calculation result obtained in step S603 (step S604) and determines whether learning is complete (step S605). Specifically, the control unit 501 can evaluate the calculation result using an error function (also referred to as an objective function, loss function, or cost function) based on the calculation result obtained in step S603 and training data. For example, the control unit 501 may determine that learning is complete when the error function becomes equal to or smaller than a threshold (or equal to or larger than a threshold) during the process of optimizing (minimizing or maximizing) the error function using a gradient descent method such as steepest descent. Note that to avoid the problem of overfitting, techniques such as cross-validation and early termination may be employed to terminate learning at an appropriate time.

[0147] If it is determined that learning is not complete (S605: NO), the control unit 501 updates the connection weights between the nodes of the learning model LM1 (step S606), returns the process to step S601, and continues learning using other training data. The control unit 501 can update the connection weights between the nodes using the backpropagation algorithm, which sequentially updates the connection weights between the nodes from the output layer to the input layer of the learning model LM1.

[0148] If it is determined that the learning is complete (S605: YES), the control unit 501 stores the learned learning model LM1 in the storage unit 502 (step S607), and ends the processing according to this flowchart.

[0149] When training data obtained by CAE analysis and training data obtained by actual measurements are available as training data, the learning model LM1 may be generated using these training data.

[0150] 20 is a flowchart illustrating a second generation method of the learning model LM1. It is assumed that the storage unit 502 of the server device 500 stores training data based on CAE analysis and training data based on actual measurements.

[0151] The control unit 501 acquires training data (CAE data) obtained by CAE analysis from the storage unit 502 (step S621) and performs learning using the CAE data (step S622). The learning procedure is similar to the procedure in the flowchart shown in Fig. 19, and involves selecting a set of data from the training data obtained by CAE analysis, inputting it into the model to be learned, performing a calculation, and evaluating the calculation result using an error function based on the calculation result and the training data, thereby progressing the learning. The control unit 501 generates an initial model by learning using the CAE data.

[0152] Next, the control unit 501 acquires actual data from the storage unit 502 (step S623) and performs additional learning using the actual data (step S624). The control unit 501 can generate a learning model LM1 by performing additional learning on the initial model generated by learning in step S622. The learning procedure is similar to the procedure in the flowchart shown in Fig. 19, and involves selecting a set of data from training data based on actual measurements, inputting it into the model to be learned (initial model), performing a calculation, and evaluating the calculation result using an error function based on the calculation result and the training data, thereby progressing the learning.

[0153] As a result of the above, the control unit 501 can generate a learning model LM1 configured to output data regarding the load weight when first data (data regarding the magnitude of hydraulic pressure including converted weight) and second data (data regarding the inclination of the special vehicle 1) are input.

[0154] The control unit 501 can create a relationship table TB1 using the generated learning model LM1. That is, the control unit 501 inputs the first data and the second data at a desired resolution into the learning model LM1 and executes calculations using the learning model LM1 to obtain an estimated load weight value. The relationship table TB1 can be created by storing the input first data and the second data and the load weight value output from the learning model LM1 as a table. Furthermore, a relationship table (not shown) with improved resolution near the maximum load weight, a relationship table TB10 for stopping ascent, and a relationship table TB20 for stopping descent can be created using a similar procedure.

[0155] The relationship table TB1 (TB10, TB20) created in the server device 500 is provided to the estimation device 100 of the specially equipped vehicle 1. The relationship table TB1 (TB10, TB20) provided to the estimation device 100 is stored in the memory unit 102 and is referred to when estimating the loaded weight.

[0156] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0157] For example, in the present embodiment, the specially equipped vehicle 1 is described as being a dump truck equipped with an estimation device 100 that estimates a load weight, a display device 120 that notifies information related to the load weight estimated by the estimation device 100, and a dump device 3. However, the present invention is not limited to dump trucks and can be applied to various specially equipped vehicles equipped with a dump device having a hydraulic cylinder. For example, the present invention can be applied to specially equipped vehicles such as a dump discharge suction vehicle, a dump discharge garbage collection vehicle, and a container detachable vehicle equipped with a loading arm. [Explanation of symbols]

[0158] 1 Specially equipped vehicles 2 Truck chassis 3 Dump 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 section 102 Storage section 103 Operation section 104 Input section 105 Output section 106 Communications Department PG1 Estimation Program CF1 Hydraulic compensation type TB1 Relationship Table

Claims

1. an acquisition unit that acquires data on the magnitude of hydraulic pressure based on an output from a pressure gauge that measures the magnitude of hydraulic pressure acting on a hydraulic actuator for a specially equipped vehicle that has the hydraulic actuator for raising and lowering a cargo box; a determination unit that determines whether it is time to update an offset value that should be applied to the magnitude of hydraulic pressure indicated by the data acquired by the acquisition unit; a calculation unit that calculates the offset value when the determination unit determines that it is time to update the offset value; a calibration unit that calibrates the data by subtracting the offset value calculated by the calculation unit from the magnitude of the hydraulic pressure indicated by the data acquired by the acquisition unit; an estimation unit that estimates the load weight of the packing box based on the calibrated data; Equipped with The determination unit determines that it is time to update the offset value when the time fluctuations of the tilt angle of the specially equipped vehicle, the tilt angle of the cargo box, and the magnitude of the hydraulic pressure are less than the respective set values, and the tilt angle of the specially equipped vehicle, the tilt angle of the cargo box, and the magnitude of the hydraulic pressure after calibration are within the respective set ranges. Specially equipped vehicle load weight estimation system.

2. The calculation unit calculates an offset value to be applied at the current timing based on the magnitude of the oil pressure when no cargo is loaded in the cargo box and the offset value calculated at the previous timing, The calibration unit calibrates the data by subtracting the offset value of the current timing calculated by the calculation unit from the magnitude of the hydraulic pressure indicated by the data acquired by the acquisition unit. The load weight estimation system according to claim 1 .

3. An acquisition unit that acquires data on 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 a specially equipped vehicle equipped with a hydraulic actuator for raising and lowering a cargo box; a calculation unit that calculates an offset value to be applied at a current timing based on the magnitude of the hydraulic pressure when no cargo is loaded in the shipping box and the offset value calculated at a previous timing; a calibration unit that calibrates the data by subtracting the offset value of the current timing calculated by the calculation unit from the magnitude of the hydraulic pressure indicated by the data acquired by the acquisition unit; an estimation unit that estimates the load weight of the packing box based on the calibrated data; A specially equipped vehicle load weight estimation system.

4. The calculation unit In order to reduce the impact of momentary fluctuations in the hydraulic pressure on the estimation accuracy, the offset value to be applied at the current timing is calculated by weighting the magnitude of the hydraulic pressure when no cargo is loaded in the cargo box and the offset calculated at the previous timing. The load weight estimation system according to claim 3 .

5. a storage unit for storing a relationship between data including data relating to the magnitude of hydraulic pressure and the load weight of the packing box; Equipped with The estimation unit estimates the load weight of the shipping box by referring to the relationship between the data stored in the storage unit.

5. The loaded weight estimation system according to claim 1.

6. and an information processing device that creates a relationship between the data by using a learning model configured to output data related to the load weight in the shipping box in response to input of data related to the magnitude of hydraulic pressure. The load weight estimation system according to claim 5 .

7. The information processing device includes: a first generation unit that generates an initial model using training data from a result of a CAE (Computer-Aided Engineering) analysis, the initial model being configured to output data related to the load weight in response to input of data related to the magnitude of the hydraulic pressure; a second generation unit that generates the learning model by additionally learning the initial model using the corrected hydraulic pressure magnitude data and the actual measured value of the load weight as training data for additional learning; The load weight estimation system according to claim 6, comprising:

8. the storage unit stores two relationships: a relationship between the data to be referenced when the packing box stops after ascending, and a relationship between the data to be referenced when the packing box stops after descending; The estimation unit estimates the load weight of the packing box by referring to one of the two relationships depending on whether the packing box has stopped after ascending or after descending. The load weight estimation system according to claim 5 .

9. The storage unit stores a first relational equation for converting first data acquired by the acquisition unit after the lifting of the container has stopped and calibrated by the calibration unit into a converted weight, and a second relational equation for converting second data acquired by the acquisition unit after the lifting of the container has stopped and calibrated by the calibration unit into a converted weight, The relationship defines a relationship between data including the converted weight converted by the first relational expression or the second relational expression and the loaded weight of the shipping box. The load weight estimation system according to claim 5 .

10. the storage unit stores a third relational expression that represents a relationship between first data acquired by the acquisition unit after the lifting of the container has stopped and calibrated by the calibration unit, and second data acquired by the acquisition unit after the lifting of the container has stopped and calibrated by the calibration unit, a correction unit that corrects either the calibrated first data or the calibrated second data using the third relational expression; The load weight estimation system according to claim 5 , comprising:

11. For a specially equipped vehicle equipped with a hydraulic actuator for raising and lowering a cargo box, data on the magnitude of the hydraulic pressure is acquired based on an output from a pressure gauge that measures the magnitude of the hydraulic pressure acting on the hydraulic actuator; Determine whether it is time to update the offset value that should be applied to the magnitude of hydraulic pressure indicated by the acquired data; When it is determined that it is time to update, the offset value is calculated, calibrating the data by subtracting the calculated offset value from the magnitude of the hydraulic pressure indicated by the acquired data; Based on the calibrated data, the load weight in the shipping box is estimated. A method for estimating the load weight of a specially equipped vehicle, which is executed by a computer, In determining whether it is time to update the offset value, if the time fluctuations of the tilt angle of the specially equipped vehicle, the tilt angle of the cargo box, and the magnitude of the hydraulic pressure are less than the respective set values, and if the tilt angle of the specially equipped vehicle, the tilt angle of the cargo box, and the magnitude of the hydraulic pressure after calibration are within the respective set ranges, it is determined that it is time to update the offset value. Method for estimating the load weight of specially equipped vehicles.

12. On the computer, For a specially equipped vehicle equipped with a hydraulic actuator for raising and lowering a cargo box, data on the magnitude of the hydraulic pressure is acquired based on an output from a pressure gauge that measures the magnitude of the hydraulic pressure acting on the hydraulic actuator; Determine whether it is time to update the offset value that should be applied to the magnitude of hydraulic pressure indicated by the acquired data; When it is determined that it is time to update, the offset value is calculated, calibrating the data by subtracting the calculated offset value from the magnitude of the hydraulic pressure indicated by the acquired data; Based on the calibrated data, the load weight in the shipping box is estimated. A computer program for executing a process, In determining whether it is time to update the offset value, if the time fluctuations of the tilt angle of the specially equipped vehicle, the tilt angle of the cargo box, and the magnitude of the hydraulic pressure are less than the respective set values, and if the tilt angle of the specially equipped vehicle, the tilt angle of the cargo box, and the magnitude of the hydraulic pressure after calibration are within the respective set ranges, it is determined that it is time to update the offset value. Computer program.

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