Weight measuring device, weight measuring method, and program

Abstract

It has a simple configuration and effectively measures the weight of the vehicle. [Solution] A weight measuring device 50 for a vehicle 1 that runs on the power of a hydraulic motor MT, comprising: acceleration acquisition means 71,100 for acquiring the acceleration A of the vehicle 1; pressure difference acquisition means 74,75,76,110 for acquiring the pressure difference ΔP between the hydraulic pressure supplied to the hydraulic motor MT and the hydraulic pressure discharged from the hydraulic motor MT; driving force calculation means 120 for calculating the driving force F of the vehicle 1 based on the pressure difference ΔP acquired by the pressure difference acquisition means 74,75,76,110; and weight calculation means 140 for calculating the weights m1 and m2 of the vehicle 1 based on the acceleration A acquired by the acceleration acquisition means 71,100 and the driving force F calculated by the driving force calculation means 120.

Description

[Technical Field]

[0001] This disclosure relates to a weight measuring device, a weight measuring method, and a program, and more particularly to a technology suitable for measuring the weight of loads placed on the cargo bed of a transport vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a technology in which multiple load cells are placed under the cargo bed of a transport vehicle, and the weight of the cargo loaded on the cargo bed is measured based on the detection results of the load cells. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-53824 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The technology described in Patent Document 1 requires the retrofitting of multiple load cells to the underside of the cargo bed. This presents challenges such as the time-consuming installation of the device and the increased cost due to the installation of multiple load cells. Furthermore, if there is an uneven distribution of the cargo loaded on the cargo bed, variations may occur in the detection results of each load cell, potentially making it impossible to fully guarantee measurement accuracy. In such cases, ensuring measurement accuracy requires calibration to correct for variations and errors in the detection results of each load cell, which presents challenges in terms of complex calculation processing.

[0005] By using existing sensors already present in the vehicle, without having to retrofit new sensors such as load cells, installation time and costs can be reduced. One example of such a method is to measure weight based on the hydraulic pressure of a hydraulic cylinder that tilts the cargo bed. However, with this method, the hydraulic pressure of the cylinder must be activated and the cargo bed tilted each time weight is measured. In other words, this increases unnecessary movements in the transport operation, leading to a decrease in work efficiency.

[0006] The technology disclosed herein has been developed in view of the above circumstances and aims to provide a technology that can effectively measure the weight of a vehicle with a simple configuration. [Means for solving the problem]

[0007] The weight measuring device disclosed herein is A weight measuring device (50) for a vehicle (1) that is driven by a hydraulic motor (MT), An acceleration acquisition means (71,100) for acquiring the acceleration (A) of the vehicle (1), A pressure difference acquisition means (74, 75, 76, 110) acquires the pressure difference (ΔP) between the hydraulic pressure supplied to the hydraulic motor (MT) and the hydraulic pressure discharged from the hydraulic motor (MT), A driving force calculation means (120) calculates the driving force (F) of the vehicle (1) based on the pressure difference (ΔP) obtained by the pressure difference acquisition means (74, 75, 76, 110), The system is characterized by comprising: a weight calculation means (140) that calculates the weight (m1, m2) of the vehicle (1) based on the acceleration (A) acquired by the acceleration acquisition means (71, 100) and the driving force (F) calculated by the driving force calculation means (120).

[0008] In another embodiment of the weight measuring device (50) of this disclosure, The aforementioned vehicle (1) is a transport vehicle equipped with a cargo bed (7), The driving force calculation means (120) calculates a first driving force (F1), which is the driving force of the vehicle (1) in an unloaded state, based on the pressure difference (ΔP) acquired by the pressure difference acquisition means (74, 75, 76, 110) when a first specific condition is met in which the vehicle (1) accelerates or decelerates in an unloaded state with no cargo loaded on the cargo bed (7), and calculates a second driving force (F2), which is the driving force of the vehicle (1) in a loaded state, based on the pressure difference (ΔP) acquired by the pressure difference acquisition means (74, 75, 76, 110) when a second specific condition is met in which the vehicle (1) accelerates or decelerates in a loaded state with cargo loaded on the cargo bed (7). It is desirable that the weight calculation means (140) calculates the weight (m2) of the load loaded on the loading platform (7) based on a first acceleration (A1), which is the acceleration in an unloaded state acquired by the acceleration acquisition means (71,100) when the first specific condition is met, a second acceleration (A2), which is the acceleration in a loaded state acquired by the acceleration acquisition means (71,100) when the second specific condition is met, the first driving force (F1), and the second driving force (F2).

[0009] In another embodiment of the weight measuring device (50) of this disclosure, The weight calculation means (140) calculates a first weight (m1), which is the weight of the unloaded vehicle (1), based on the first acceleration (A1) and the first driving force (F1). The system further includes a storage means (135) for storing the first acceleration (A1), the first driving force (F1), and the first weight (m1), When the second specific condition is met, if the difference between the second driving force (F2) calculated by the driving force calculation means (120) and the first driving force (F1) stored in the storage means (135) is less than or equal to a predetermined value, the weight calculation means (140) preferably calculates the weight (m2) of the load by multiplying the first weight (m1) by the difference between the first acceleration (A1) and the second acceleration (A2) and dividing the result by the second acceleration (A2).

[0010] In a weighing device (50) according to another aspect of the present disclosure, the first specific condition is satisfied when the vehicle (1) starts to accelerate after stopping and unloading the load from the loading platform (7), and it is desirable that the second specific condition is satisfied when the vehicle (1) starts to accelerate after stopping and loading the load onto the loading platform (7).

[0011] In a weighing device (50) according to another aspect of the present disclosure, the first specific condition is satisfied when the vehicle (1) accelerates or decelerates on the path moving from a predetermined loading location to a predetermined unloading location, and it is desirable that the second specific condition is satisfied when the vehicle (1) accelerates or decelerates on the path moving from a predetermined unloading location to a predetermined loading location.

[0012] The weighing method of the present disclosure is a method for weighing a vehicle (1) driven by the power of a hydraulic motor (MT), acquiring an acceleration (A) of the vehicle (1), acquiring a pressure difference (ΔP) between the hydraulic pressure supplied to the hydraulic motor (MT) and the hydraulic pressure discharged from the hydraulic motor (MT), calculating a driving force (F) of the vehicle (1) based on the acquired pressure difference (ΔP), and calculating a weight (m1, m2) related to the vehicle (1) based on the acquired acceleration (A) and the calculated driving force (F).

[0013] The program of the present disclosure is for a computer of a weighing device (50) of a vehicle (1) driven by the power of a hydraulic motor (MT), a process of acquiring an acceleration (A) of the vehicle (1), a process of acquiring a pressure difference (ΔP) between the hydraulic pressure supplied to the hydraulic motor (MT) and the hydraulic pressure discharged from the hydraulic motor (MT), A process to calculate the driving force (F) of the vehicle (1) based on the acquired pressure difference (ΔP), The system is characterized by performing a process to calculate the weight (m1, m2) of the vehicle (1) based on the acquired acceleration (A) and the calculated driving force (F).

[0014] In the above description, for the purpose of aiding understanding of this disclosure, the reference numerals used in the embodiments are indicated in parentheses for the constituent elements corresponding to the embodiments; however, each constituent element is not limited to the embodiments defined by the aforementioned reference numerals. [Effects of the Invention]

[0015] According to the technology disclosed herein, the weight of a vehicle can be effectively measured with a simple configuration. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram illustrating an overall overview of an example of a vehicle to which the weight measuring device according to this embodiment is applied. [Figure 2] This is a skeleton diagram illustrating an example of the drive system of a vehicle to which the weight measuring device according to this embodiment is applied. [Figure 3] This is a skeleton diagram illustrating an example of the drive system of a vehicle to which the weight measuring device according to this embodiment is applied. [Figure 4] This is a skeleton diagram illustrating an example of the drive system of a vehicle to which the weight measuring device according to this embodiment is applied. [Figure 5] This is a schematic block diagram showing the weight measuring device according to this embodiment. [Figure 6] This is a schematic diagram showing the software configuration of the weight measuring device according to this embodiment. [Figure 7] This flowchart illustrates the routine for calculating the unloaded weight according to this embodiment. [Figure 8] This is a flowchart illustrating the routine for calculating the weight of the load according to this embodiment. [Modes for carrying out the invention]

[0017] The weight measuring device, weight measuring method, and program according to this embodiment will be described below based on the attached drawings.

[0018] [Overall vehicle overview] First, before describing the details of this embodiment, we will begin by describing an overview of an example of a vehicle to which this embodiment is applied.

[0019] Figure 1 is a schematic diagram of a carrier dump truck, an example of a vehicle (transport vehicle) 1, viewed from the side. A carrier dump truck is sometimes also called a crawler carrier or crawler dump truck. A carrier dump truck comprises a crawler-type lower traveling body 2 and an upper rotating body 6 provided on top of the lower traveling body 2.

[0020] The lower running body 2 includes drive wheels 3, idler wheels 4, and endless crawler tracks 5 wrapped around the drive wheels 3 and idler wheels 4. Rotational power is transmitted to the drive wheels 3 from the drive system (see Figures 2-4), which will be described later. When rotational power is transmitted to the drive wheels 3, the crawler tracks 5 rotate, causing the carrier dump truck to move.

[0021] The upper rotating body 6 is rotatably mounted on the lower traveling body 2. The upper rotating body 6 is equipped with a vessel (cargo bed) 7 for loading excavated soil generated in construction and civil engineering works, or concrete to be poured into designated locations, a cabin 8 for the operator, and the like. The vessel 7 is tiltably mounted on the upper rotating body 6 via a hydraulic cylinder (not shown) or the like. When discharging the load on the vessel 7, the vessel 7 is tilted.

[0022] Furthermore, the vehicles to which this disclosure can be applied are not limited to the carrier dump shown in Figure 1, but may also be other transport vehicles equipped with a loading platform, such as rigid dump trucks, articulated dump trucks, and scrapers. The vehicles may also be equipped with buckets, such as hydraulic excavators and wheel loaders. Additionally, the vehicle's running gear is not limited to crawler type, but may be wheel type.

[0023] [Overview of the drive system] Next, an overview of the drive system of a vehicle to which the weight measuring device according to this embodiment is applied will be described based on Figures 2 to 4. Note that the configuration shown in Figures 2 to 4 is just one example of a drive system, and other configurations are also possible.

[0024] The drive system 10 shown in Figure 2 comprises an engine E, a hydraulic pump P driven by the power of the engine E, and a hydraulic motor M that is rotationally driven by the hydraulic pressure supplied from the hydraulic pump P. A reduction mechanism RG is also provided on the output side of the hydraulic motor M. The reduction mechanism RG comprises, in order from the upstream side in the power transmission direction, a parallel shaft gear reduction mechanism 11, a bevel gear mechanism 12, and a pair of left and right planetary gear mechanisms 13L and 13R.

[0025] The parallel-shaft gear reduction mechanism 11 includes an input shaft 11A directly connected to the rotation shaft of the hydraulic motor M, an output shaft 11B arranged parallel to the input shaft 11A, a low-speed gear train 11L, and a high-speed gear train 11H. The low-speed gear train 11L and the high-speed gear train 11H are provided so as to be rotatable relative to either the input shaft 11A or the output shaft 11B. In the example shown in Figure 2, the low-speed gear train 11L and the high-speed gear train 11H are provided so as to be rotatable relative to the output shaft 11B. For this reason, the output shaft 11B is provided with a clutch 11C that selectively couples the low-speed gear train 11L or the high-speed gear train 11H so as to be rotatable integrally with the output shaft 11B. The operation of the clutch 11C is switched by the operator operating a shift operation unit (not shown) provided in the cabin 8 (see Figure 1).

[0026] The output shaft 11B of the parallel-axis gear reduction mechanism 11 is connected to the bevel gear mechanism 12. The bevel gear mechanism 12 includes a first bevel gear 12A provided at the output end of the output shaft 11B and a second bevel gear 12B that is always meshed with the first bevel gear 12A. The rotational power input from the output shaft 11B is distributed to the left and right planetary gear mechanisms 13L and 13R via the bevel gear mechanism 12.

[0027] The left and right pair of planetary gear mechanisms 13L, 13R each include sun gears 14L, 14R that are integrally rotatable to the second bevel gear 12B, a plurality of planetary gears 17L, 17R that are rotatably supported by carriers 15L, 15R and mesh with the sun gears 14L, 14R, and ring gears 18L, 18R with internal teeth that mesh with the planetary gears 17L, 17R. The left and right carriers 15L, 15R are integrally rotatable to the drive wheels 3 via shafts 19L, 19R.

[0028] With the drive system 10 configured as described above, during low-speed driving, the clutch 11C connects the low-speed gear train 11L to the output shaft 11B. That is, the rotational power of the hydraulic motor M is input from the low-speed gear train 11L of the parallel-axis gear reduction mechanism 11, via the output shaft 11B to the bevel gear mechanism 12, and transmitted to the drive wheels 3 via the left and right planetary gear mechanisms 13L and 13R. On the other hand, during high-speed driving, the clutch 11C connects the high-speed gear train 11H to the output shaft 11B. That is, the rotational power of the hydraulic motor M is input from the high-speed gear train 11H of the parallel-axis gear reduction mechanism 11, via the output shaft 11B to the bevel gear mechanism 12, and transmitted to the drive wheels 3 via the left and right planetary gear mechanisms 13L and 13R.

[0029] The drive system 20 shown in Figure 3 comprises an engine E, a hydraulic pump P driven by the power of the engine E, a pair of left and right hydraulic motors ML and MR that are rotationally driven by the hydraulic pressure supplied from the hydraulic pump P, and a reduction mechanism RG. The reduction mechanism RG includes a pair of left and right planetary gear mechanisms 21L and 21R. The symbol H in the figure indicates the housing. Since the left hydraulic motor ML and left planetary gear mechanism 21L that constitute the left power transmission path and the right hydraulic motor MR and right planetary gear mechanism 21R that constitute the right power transmission path are configured similarly, only the configuration of the left side will be described below. In the following, the left hydraulic motor ML will be simply referred to as the hydraulic motor, and the left planetary gear mechanism 21L will be simply referred to as the planetary gear mechanism.

[0030] A sun gear 22 of a planetary gear mechanism 21L is rotatably mounted on the motor output shaft MS of the hydraulic motor ML. Multiple planetary gears 23 mesh with the sun gear 22. The multiple planetary gears 23 mesh with the internal teeth of a ring gear 24. An output shaft 26 is fixed to a carrier 25 that rotatably supports the planetary gears 23. A drive wheel 3 is rotatably connected to the output end of the output shaft 26.

[0031] A high-speed clutch 27 is provided between the carrier 25 and the motor output shaft MS to selectively connect the carrier 25 and the motor output shaft MS. A low-speed clutch 28 is provided between the ring gear 24 and the housing H to selectively connect the ring gear 24 and the housing H. The operation of the high-speed clutch 27 and the low-speed clutch 28 can be switched by the operator operating a shift control unit (not shown) located in the cabin 8 (see Figure 1).

[0032] With the drive system 20 configured as described above, during low-speed driving, the low-speed clutch 28 connects the ring gear 24 to the housing H, and the high-speed clutch 27 is released. That is, the rotational power of the hydraulic motor ML is input from the motor output shaft MS to the sun gear 22. At this time, since the ring gear 24 is fixed, the rotational power input to the sun gear 22 is transmitted from the planetary gear 23, through the carrier 25, and from the output shaft 26 to the drive wheels 3. On the other hand, during high-speed driving, the high-speed clutch 27 connects the carrier 25 to the motor output shaft MS, and the low-speed clutch 28 is released, thereby directly connecting the motor output shaft MS and the carrier 25. That is, the rotational power of the hydraulic motor ML is transmitted from the motor output shaft MS, through the carrier 25, and from the output shaft 26 to the drive wheels 3.

[0033] The drive system 30 shown in Figure 4 comprises an engine E, a hydraulic pump P driven by the power of the engine E, a pair of left and right variable displacement hydraulic motors MVL and MVR that are rotationally driven by the hydraulic pressure supplied from the hydraulic pump P, and a reduction mechanism RG. The reduction mechanism RG includes a pair of left and right planetary gear mechanisms 31L and 31R. Since the left variable displacement hydraulic motor MVL and left planetary gear mechanism 31L that constitute the left power transmission path and the right variable displacement hydraulic motor MVR and right planetary gear mechanism 31R that constitute the right power transmission path are configured similarly, only the configuration of the left side will be described below. Furthermore, below, the left variable displacement hydraulic motor MVL will be simply referred to as a variable displacement hydraulic motor, and the left planetary gear mechanism 31L will be simply referred to as a planetary gear mechanism.

[0034] The variable displacement hydraulic motor MVL is, for example, a swash plate type variable displacement motor. A sun gear 34 of a planetary gear mechanism 31L is rotatably mounted on the motor output shaft MS of the variable displacement hydraulic motor MVL. The sun gear 34 meshes with a plurality of planetary gears 33. The plurality of planetary gears 33 mesh with the internal teeth of a ring gear 32 fixed to the housing H. A drive wheel 3 is rotatably connected to a carrier 35 that rotatably supports the planetary gears 33 via an output shaft 36. That is, the rotational power of the variable displacement hydraulic motor MVL is reduced by a predetermined reduction ratio by the planetary gear mechanism 31L and transmitted to the drive wheel 3. With the drive system 30 configured as described above, the vehicle's travel speed can be switched between low speed and high speed by increasing or decreasing the tilt angle of the swash plate of the variable displacement hydraulic motor MVL.

[0035] In the following explanation, the hydraulic motor M shown in Figure 2, the hydraulic motors ML and MR shown in Figure 3, and the variable displacement hydraulic motors MVL and MVR shown in Figure 4 will be referred to simply as "hydraulic motor MT" for convenience.

[0036] [Weight measuring device] Figure 5 is a schematic block diagram showing a weight measuring device 50 according to this embodiment. As shown in Figure 5, the weight measuring device 50 has an information processing device 60. The information processing device 60 is a so-called microcomputer equipped with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and an interface IF, etc. ROM is a non-volatile memory that stores data necessary for the CPU to execute various programs. RAM is a volatile memory that provides a work area that is expanded when various programs are executed by the CPU. The interface IF is a communication device for communicating with external devices.

[0037] The information processing device 60 is the central device for performing calculations related to weight measurement. For this reason, the information processing device 60 is connected to the vehicle status acquisition device 70, the external communication device 80, the location information acquisition device 85, the HMI (Human Machine Interface) 90, and other devices in a communication manner.

[0038] The vehicle status acquisition device 70 consists of sensors that acquire the status of vehicle 1. Specifically, the vehicle status acquisition device 70 includes a vehicle speed sensor (or wheel speed sensor) 71, an accelerator sensor 72, a brake sensor 73, a first supply hydraulic pressure sensor 74, a second supply hydraulic pressure sensor 75, a discharge hydraulic pressure sensor 76, a shift position sensor 77, and the like.

[0039] The vehicle speed sensor 71 detects the vehicle speed (hereinafter referred to as vehicle speed V) of the vehicle 1. The accelerator sensor 72 detects the depressing of the accelerator pedal (not shown) by the operator of the vehicle 1. The brake sensor 73 detects the depressing of the brake pedal (not shown) by the driver. The accelerator and brake may be operated by levers, etc. In that case as well, the accelerator sensor 72 and brake sensor 73 detect the amount of operation of the levers, etc. Furthermore, depending on the type of vehicle 1 (for example, a carrier dump truck), the vehicle may be configured such that when the travel lever is pushed forward, it moves forward; when pushed backward, it moves backward; and when returned to the neutral position, the accelerator opening becomes 0 (zero), causing it to decelerate and stop. In such a case, the brake sensor 73 is not present and is used in conjunction with the accelerator sensor 72. The first supply hydraulic pressure sensor 74 detects the hydraulic pressure (hereinafter referred to as forward supply hydraulic pressure Pf) supplied from the hydraulic pump P to the hydraulic motor MT (see Figures 2-4) when the vehicle 1 is moving forward. The second supply hydraulic pressure sensor 75 detects the hydraulic pressure supplied from the hydraulic pump P to the hydraulic motor MT (see Figures 2-4) when the vehicle 1 is moving in reverse (hereinafter referred to as the reverse supply hydraulic pressure Pb). The discharge hydraulic pressure sensor 76 detects the hydraulic pressure at the drain port of the hydraulic motor MT (see Figures 2-4) (hereinafter referred to as the discharge hydraulic pressure Pd). The shift position sensor 77 detects the operating position (low speed, high speed, etc.) of the shift operation unit (not shown) located in the cabin 8 (see Figure 1). The vehicle status acquisition device 70 repeatedly transmits the status of the vehicle 1 detected by each of the sensors 71-77 to the information processing device 60 at a predetermined interval.

[0040] The external communication device 80 is a communication device that communicates between the vehicle 1 and an external device (for example, an information processing device installed in a management office, a smartphone or tablet carried by a worker at the site, etc.). The external communication device 80 can, for example, provide information about the vehicle 1 to the external device via wireless communication, or receive commands from the external device.

[0041] The location information acquisition device 85 is, for example, a GPS (Global Positioning System), a GNSS (Global Navigation Satellite System), etc., and acquires the current location information of the vehicle 1. The location information acquisition device 85 repeatedly transmits the acquired current location information of the vehicle 1 to the information processing device 60 at a predetermined interval.

[0042] The HMI 90 is an interface for inputting and outputting information between the vehicle 1 and the operator, and includes an input device 91 and an output device 92 located within the cabin 8 (see Figure 1). Examples of the input device 91 include a touch panel, physical switches, and a sound-collecting microphone. Examples of the output device 92 include a display and a speaker.

[0043] [Software Configuration] Figure 6 is a schematic diagram showing the software configuration of the weight measuring device according to this embodiment.

[0044] As shown in Figure 6, the information processing device 60 includes as functional elements an acceleration calculation unit 100, a pressure difference calculation unit 110, a driving force calculation unit 120, an unloaded calculation processing unit 130, an unloaded calculation value storage unit 135, a loaded calculation processing unit 140, an alarm control unit 150, and the like. Each of these functional elements 100 to 150 is realized by the CPU of the information processing device 60 reading a program stored in ROM into RAM and executing it. Note that all or part of each of the functional elements 100 to 150 can also be provided in another information processing device separate from the information processing device 60 (for example, an information processing device of a management office that can communicate with the vehicle 1).

[0045] The acceleration calculation unit 100 calculates the acceleration A of the vehicle 1 at a predetermined period based on the detection result of the vehicle speed sensor 71. The acceleration calculation unit 100 calculates acceleration A by differentiating the vehicle speed V detected by the vehicle speed sensor 71, for example. In order to improve the accuracy of the acceleration calculation, the acceleration calculation unit 100 may, for example, calculate the average value of n consecutive accelerations A (where n is an integer of 2 or more) calculated at a predetermined period. If the vehicle 1 is equipped with an acceleration sensor capable of detecting acceleration in the longitudinal direction of the vehicle body, the acceleration calculation unit 100 may directly obtain acceleration A from the detection result of the acceleration sensor.

[0046] The pressure difference calculation unit 110 calculates a pressure difference ΔP, which is the difference between the hydraulic pressure supplied from the hydraulic pump P to the hydraulic motor MT on the supply port side (hereinafter referred to as forward supply hydraulic pressure Pf or reverse supply hydraulic pressure Pr) and the hydraulic pressure discharged from the hydraulic motor MT on the drain port side (hereinafter referred to as discharge hydraulic pressure Pd), based on the detection results of the first or second supply hydraulic pressure sensors 74, 75 and the detection results of the discharge hydraulic pressure sensor 76.

[0047] Specifically, the pressure difference calculation unit 110 determines whether the vehicle 1 is moving forward or in reverse based on the detection results of the vehicle speed sensor 71 and the shift position sensor 77. If the pressure difference calculation unit 110 determines that the vehicle 1 is moving forward, it calculates the pressure difference ΔP (= Pf - Pd) by subtracting the discharged oil pressure Pd detected by the discharged oil pressure sensor 76 from the forward-moving supply oil pressure Pf detected by the first supply oil pressure sensor 74. If the pressure difference calculation unit 110 determines that the vehicle 1 is moving in reverse, it calculates the pressure difference ΔP (= Pr - Pd) by subtracting the discharged oil pressure Pd detected by the discharged oil pressure sensor 76 from the reverse-moving supply oil pressure Pr detected by the second supply oil pressure sensor 75. The timing for calculating the pressure difference ΔP may be by repeatedly calculating it at a predetermined period, or by calculating it when the acceleration A (absolute value) calculated by the acceleration calculation unit 100 becomes equal to or greater than a predetermined value, or by calculating it when a command is received from the unloaded calculation processing unit 130 or the loaded calculation processing unit 140, which will be described later.

[0048] The drive force calculation unit 120 calculates the drive force F transmitted from the hydraulic motor MT to the drive wheel 3. The specific procedure for calculating the drive force F will be described below.

[0049] Output torque T from the hydraulic motor MT IN This is shown by the following formula (1).

number

[0050] The transmission torque T is transmitted from the hydraulic motor MT to the drive wheel 3 via the reduction mechanism RG. OUT This is shown by the following formula (2).

number

[0051] From equations (1) and (2), the driving force F of vehicle 1 is expressed by the following equation (3).

number

[0052] The driving force calculation unit 120 calculates the driving force F of the vehicle 1 by substituting the pressure difference ΔP calculated by the pressure difference calculation unit 110 into formula (3). For the reduction ratio R, the high-speed and low-speed reduction ratios of the reduction mechanism RG can be calculated in advance from catalog values, etc., and stored in the storage unit (e.g., ROM) of the information processing device 60. Whether to substitute the high-speed or low-speed reduction ratio can be determined based on the detection result of the shift position sensor 77. The radius r of the drive wheel 3, the displacement volume q of the hydraulic motor MT, and the torque efficiency η are also considered. tRegarding the torque transmission efficiency η, catalog values ​​or the like can be stored in the memory of the information processing device 60 in advance as an intrinsic value corresponding to the specific specifications of the vehicle 1. Alternatively, these values ​​can be obtained in advance by conducting experiments or simulations and stored in the memory. The timing at which the driving force calculation unit 120 calculates the driving force F can be repeated at a predetermined period, or it can be calculated when it receives a command from the unloaded calculation processing unit 130 or the loaded calculation processing unit 140, which will be described later.

[0053] The unloaded calculation processing unit 130 calculates the weight of the vehicle 1 in an unloaded state (hereinafter referred to as the unloaded weight m1) based on the acceleration A calculated by the acceleration calculation unit 100 and the driving force F calculated by the driving force calculation unit 120 when the vehicle 1 is accelerating or decelerating in an unloaded state where no cargo is loaded onto the vessel 7. In this disclosure, the unloaded state includes not only the state in which there is no cargo loaded onto the vessel 7, but also the state in which a very small amount or a small amount of cargo remains on the vessel 7.

[0054] The unloaded calculation processing unit 130 determines whether a first specific condition is met for vehicle 1 to accelerate or decelerate while unloaded. The first specific condition is met, for example, when either condition (1) or condition (2) below is met. Condition (1) When vehicle 1 has stopped and unloaded its cargo from vessel 7, and then accelerates to start driving. Condition (2) When, on the route taken by vehicle 1 from the unloading area to the loading area, the driving state of vehicle 1 transitions from constant speed driving to accelerating driving or decelerating driving.

[0055] Whether vehicle 1 has unloaded its cargo from the vessel 7 can be recognized, for example, based on whether the vessel 7 can be tilted. Alternatively, whether the cargo has been unloaded can be recognized by receiving operation input from the operator of vehicle 1 to the HMI 90. Furthermore, whether vehicle 1 has accelerated or decelerated can be recognized, for example, when the absolute value of acceleration A calculated by the acceleration calculation unit 100 exceeds a predetermined value. Alternatively, acceleration or deceleration of vehicle 1 can be recognized based on the detection results of the accelerator sensor 72 and the brake sensor 73 (however, if the brake sensor 73 is also used as the accelerator sensor 72, only the accelerator sensor 72 can be used). Whether vehicle 1 is moving from the unloading location to the loading location can be recognized, for example, by receiving operation input from the operator of vehicle 1 to the HMI 90. Alternatively, if BIM / CIM data or a map database is provided, this can be recognized by referring to them based on the current position of vehicle 1 acquired by the position information acquisition device 85. In this case, BIM / CIM data and map databases may be stored in the memory unit of the information processing device 60, or they may be obtained from an external device (for example, an information processing device such as a management office that can communicate with the vehicle 1) via the external communication device 80.

[0056] Furthermore, the unloaded calculation processing unit 130 may determine that the first specific condition is met if the vehicle 1 is accelerating or decelerating when the operator of the vehicle 1 inputs a request for unloaded weight measurement from the HMI 90.

[0057] When the first specific condition is met, the unloaded calculation processing unit 130 calculates the unloaded weight m1 (=F1 / A1) by dividing the driving force calculated by the driving force calculation unit 120 when the first specific condition is met (hereinafter referred to as the unloaded driving force F1) by the acceleration calculated by the acceleration calculation unit 100 (hereinafter referred to as the unloaded acceleration A1). The unloaded driving force F1, unloaded acceleration A1, and unloaded weight m1 calculated by the unloaded calculation processing unit 130 are transmitted to the unloaded calculation value storage unit 135.

[0058] Here, when calculating the unloaded weight m1, if the slope of the road surface during the running of the vehicle 1 is large, it is desirable to consider the influence of the slope resistance. The unloaded calculation processing unit 130 may use the unloaded driving force F1 and the unloaded acceleration A1 calculated at time t1, and the unloaded driving force F1 and the unloaded acceleration A1 calculated at time t2 when a relatively short time has elapsed from time t1, so as to eliminate the influence of the slope resistance. Specifically, the unloaded calculation processing unit 130 sets the unloaded driving force calculated at time t1 as the first unloaded driving force F 1_1 , the unloaded acceleration as the first unloaded acceleration A 1_1 , sets the unloaded driving force calculated at time t2 as the second unloaded driving force F 1_2 , and the unloaded acceleration as the second unloaded acceleration A 1_2 . In this case, the difference between the second unloaded driving force F 1_2 and the first unloaded acceleration A 1_1 is divided by the difference between the second unloaded acceleration A 1_2 and the first unloaded acceleration A 1_1 to obtain the unloaded weight m1 (= (F 1_2 - F 1_1 ) / (A 1_2 - A 1_1 )).

[0059] In addition, when the vehicle 1 is equipped with a slope sensor, the slope of the road surface detected by the slope sensor, or when the vehicle 1 is equipped with an acceleration sensor, the slope of the road surface estimated based on the detection result of the acceleration sensor may be used to consider the influence of the slope resistance. Alternatively, the influence of the road surface slope may be eliminated by adding the condition that the vehicle 1 is running on a flat road to the above conditions (1) and (2), and performing the calculation of the unloaded weight m1 only on the flat road.

[0060] The unloaded calculation value storage unit 135 stores the unloaded driving force F1, unloaded acceleration A1, and unloaded weight m1 calculated by the unloaded calculation processing unit 130. In this case, the unloaded calculation value storage unit 135 stores the unloaded acceleration A1 and unloaded weight m1 in association with the unloaded driving force F1. Furthermore, if the unloaded calculation processing unit 130 calculates the unloaded weight m1 considering the effect of gradient resistance, the unloaded calculation value storage unit 135 also stores the road surface gradient (hereinafter referred to as the unloaded road surface gradient) in association with the unloaded driving force F1.

[0061] The loading calculation processing unit 140 calculates the weight of the load loaded onto the vessel 7 (hereinafter referred to as the load weight m1). Specifically, the loading calculation processing unit 140 determines whether the second specific condition is met, which is when the vehicle 1 loads the load onto the vessel 7 and accelerates or decelerates. The second specific condition is met, for example, when the following condition (3) or condition (4) is met. Condition (3) When vehicle 1 stops, loads cargo onto vessel 7, and then accelerates to start driving. Condition (4) When, on the path that Vehicle 1 is moving from the loading area to the unloading area, the driving state of Vehicle 1 transitions from constant speed driving to accelerating driving or decelerating driving.

[0062] Whether or not vehicle 1 has loaded cargo onto the vessel 7 can be determined, for example, by receiving operation input from the operator of vehicle 1 to the HMI 90. Alternatively, it can be determined by referring to BIM / CIM data or a map database based on the current position of vehicle 1 acquired by the position information acquisition device 85, and determining whether vehicle 1 is located at the loading location. Furthermore, whether vehicle 1 has accelerated or decelerated can be determined, for example, by determining if the absolute value of acceleration A calculated by the acceleration calculation unit 100 exceeds a predetermined value. Alternatively, the acceleration or deceleration of vehicle 1 can be determined based on the detection results of the accelerator sensor 72 or brake sensor 73 (however, if the brake sensor 73 is also used as the accelerator sensor 72, only the accelerator sensor 72 is used). Whether or not vehicle 1 is moving from the loading location to the unloading location can be determined, for example, by receiving operation input from the operator of vehicle 1 to the HMI 90. Alternatively, if BIM / CIM data or a map database is provided, it may be recognized by referencing them based on the current position of the vehicle 1 obtained by the position information acquisition device 85.

[0063] Furthermore, the loading calculation processing unit 140 may determine that the second specific condition is met if the vehicle 1 is accelerating or decelerating when the operator of the vehicle 1 inputs a request for weight measurement of the load to the HMI 90.

[0064] When the second specific condition is met, the loading calculation processing unit 140 obtains the driving force calculated by the driving force calculation unit 120 (hereinafter referred to as the loaded driving force F2) and the acceleration calculated by the acceleration calculation unit 100 (hereinafter referred to as the loaded acceleration A2) when the second specific condition is met. Furthermore, when the loading weight calculation unit 140 obtains the loaded driving force F2, it searches the unloaded driving force F1, which has the same value as the loaded driving force F2, from the unloaded calculation value storage unit 135. Here, the statement that the loaded driving force F2 and the unloaded driving force F1 have the same value is not limited to cases where these values ​​match, but also includes cases where the difference between them is small (when the difference is less than or equal to a predetermined value).

[0065] When the loading calculation processing unit 140 finds an empty load driving force F1 in the empty load calculation value storage unit 135 that has the same value as the loading driving force F2, it extracts and reads the empty load acceleration A1 and empty load m1 stored in association with the empty load driving force F1 from the empty load calculation value storage unit 135. Furthermore, once the loading calculation processing unit 140 has extracted the empty load acceleration A1 and empty load m1, it calculates the load weight m2 by substituting the loading acceleration A2, empty load acceleration A1, and empty load m1 into the following formula (4).

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[0066] In this embodiment, the weight m1 of the load can be measured without retrofitting any new sensors such as load cells by using the detection results of the existing sensors 71, 74, 75, and 76 installed on the vehicle 1. In other words, the effort and cost of installing sensors can be effectively reduced. Furthermore, even if there is an imbalance in the load on the cargo bed 7, the detection results of the vehicle speed sensor 71 and the hydraulic sensors 74, 75, and 76 are not affected, thus effectively ensuring measurement accuracy. In addition, there is no need to tilt the cargo bed 7 or position the vehicle 1 in a specific way to measure the weight m1 of the load, and the measurement can be performed as part of the series of operations during the transport operation, thus effectively preventing a decrease in work efficiency.

[0067] By the way, when calculating the weight of the load in m2, it is desirable to consider the effect of gradient resistance when the gradient of the road surface during travel is large. If the vehicle 1 is equipped with a gradient sensor or an acceleration sensor, the loading calculation processing unit 140 acquires the road surface gradient when the second specific condition is met (hereinafter referred to as the loading road surface gradient) based on the detection results of these gradient sensors or acceleration sensors. If there is an unloaded driving force F1 in the unloaded calculation value storage unit 135 that shows the same value as the loading driving force F2, the loading calculation processing unit 140 extracts the unloaded driving force F1 that shows the same value as the loading driving force F2 and is associated with an unloaded gradient resistance that shows approximately the same value as the loading road surface gradient. The loading calculation processing unit 140 extracts the unloaded driving force F1, then extracts the unloaded acceleration A1 and unloaded load m1 stored in association with the unloaded driving force F0, and substitutes them into the above formula (4) to calculate the load weight m2. This makes it possible to calculate the load weight m2 with high accuracy, taking into account gradient resistance.

[0068] Furthermore, conditions (3) and (4) above may be amended to include the case where vehicle 1 is traveling on a flat road, and the calculation of the load weight m1 may be performed only on a flat road to eliminate the effect of the road surface gradient.

[0069] The alarm control unit 150 determines that the weight of the load m2 calculated by the loading calculation processing unit 140 is equal to a predetermined upper limit threshold weight m Max If the load exceeds a certain limit, an alarm control is implemented to alert the operator of vehicle 1 to the overload. The alarm control can be performed, for example, by displaying a warning image on the HMI 90's display or by outputting an alarm sound from the speaker. The alarm control unit 150 may also transmit the detection result to an external device via the external communication device 80 when it detects overload. In addition, the alarm control unit 150 can also be configured to perform a stop control that forcibly stops vehicle 1 in addition to the alarm control when it detects overload.

[0070] Next, based on the flowchart shown in Figure 7, the routine for calculating the unloaded weight executed by the CPU of the information processing device 60 will be described. This routine is started, for example, when vehicle 1 is driven.

[0071] In step S100, the CPU of the information processing device 60 determines whether the first specific condition is met. The first specific condition is met if either condition (1) the vehicle 1 starts moving after unloading the cargo from the vessel 7, or condition (2) the vehicle 1's driving state transitions from constant speed driving to accelerating driving or decelerating driving while moving along the path from the unloading place to the loading place. If the first specific condition is met (Yes), the CPU of the information processing device 60 proceeds to the process in step S110. On the other hand, if the first specific condition is not met (No), the CPU of the information processing device 60 returns this routine.

[0072] In step S110, the CPU of the information processing device 60 calculates the unloaded acceleration A1 by differentiating the vehicle speed V detected by the vehicle speed sensor 71. Next, in step S120, the CPU of the information processing device 60 calculates the pressure difference ΔP, which is the difference between the hydraulic pressure on the supply port side supplied from the hydraulic pump P to the hydraulic motor MT (hereinafter referred to as forward supply hydraulic pressure Pf or reverse supply hydraulic pressure Pr) and the hydraulic pressure on the drain port side discharged from the hydraulic motor MT (hereinafter referred to as discharge hydraulic pressure Pd), based on the detection results of the first or second supply hydraulic pressure sensors 74, 75 and the detection result of the discharge hydraulic pressure sensor 76.

[0073] Next, in step S130, the CPU of the information processing device 60 calculates the unloaded driving force F1 based on the pressure difference ΔP calculated in step S120 and the above-mentioned formula (3). Note that the processing in step S110 and the processing in steps S120 and S130 are not in any particular order, and the processing in step S110 may be performed after the processing in steps S120 and S130, or they may be performed simultaneously.

[0074] In step S140, the CPU of the information processing device 60 calculates the unloaded weight m1 (=F1 / A1) by dividing the unloaded driving force F1 calculated in step S130 by the unloaded acceleration A1 calculated in step S110.

[0075] In step S150, the CPU of the information processing device 60 stores the unloaded acceleration A1 calculated in step S110 and the unloaded weight m1 calculated in step S140, linked to the unloaded driving force F1 calculated in step S130, and returns this routine.

[0076] Next, the routine for calculating the load weight executed by the CPU of the information processing device 60 will be explained based on the flowchart shown in Figure 8. This routine is started, for example, when vehicle 1 is driven.

[0077] In step S200, the CPU of the information processing device 60 determines whether the second specific condition is met. The first specific condition is met if either condition (3) the vehicle 1 starts accelerating to begin driving after loading cargo onto the vessel 7, or condition (4) the vehicle 1's driving state transitions from constant speed driving to accelerating driving or decelerating driving on the path the vehicle 1 is traveling from the loading area to the unloading area. If the second specific condition is met (Yes), the CPU of the information processing device 60 proceeds to the process in step S210. On the other hand, if the second specific condition is not met (No), the CPU of the information processing device 60 returns this routine.

[0078] In step S210, the CPU of the information processing device 60 calculates the load acceleration A2 by differentiating the vehicle speed V detected by the vehicle speed sensor 71. Next, in step S220, the CPU of the information processing device 60 calculates the pressure difference ΔP, which is the difference between the hydraulic pressure on the supply port side supplied from the hydraulic pump P to the hydraulic motor MT (hereinafter referred to as forward supply hydraulic pressure Pf or reverse supply hydraulic pressure Pr) and the hydraulic pressure on the drain port side discharged from the hydraulic motor MT (hereinafter referred to as discharge hydraulic pressure Pd), based on the detection results of the first or second supply hydraulic pressure sensors 74, 75 and the detection results of the discharge hydraulic pressure sensor 76.

[0079] Next, in step S230, the CPU of the information processing device 60 calculates the load-bearing driving force F2 based on the pressure difference ΔP calculated in step S220 and the above-mentioned formula (3). Note that the processing in step S210 and the processing in steps S220 and S230 are not in any particular order, and the processing in step S210 may be performed after the processing in steps S220 and S230, or they may be performed simultaneously.

[0080] In step S240, the CPU of the information processing device 60 determines whether it has stored an unloaded driving force F1 that is the same as or approximately the same as the loaded driving force F2 calculated in step S230. If it has stored an unloaded driving force F1 that is the same as or approximately the same as the loaded driving force F2 (Yes), the CPU of the information processing device 60 proceeds to the process in step S250. On the other hand, if it does not have stored an unloaded driving force F1 that is the same as or approximately the same as the loaded driving force F2 (No), the CPU of the information processing device 60 returns this routine.

[0081] In step S250, the CPU of the information processing device 60 reads out the unloaded acceleration A1 and the unloaded weight m1, which are stored in association with the unloaded driving force F1. Next, in step S260, the CPU of the information processing device 60 calculates the loaded weight m2 by substituting the loaded acceleration A2 calculated in step S210, the unloaded acceleration A1 read out in step S250, and the unloaded weight m1 into the above formula (4).

[0082] In step S270, the CPU of the information processing device 60 outputs the load weight m2 calculated in step S260 to the output device 92 (for example, the display) of the HMI 90. Then, in step S280, the CPU of the information processing device 60 determines that the load weight m2 calculated in step S260 is the upper limit threshold weight m Max Determine whether it exceeds the upper limit threshold weight m Max If it exceeds (Yes), the CPU of the information processing device 60 proceeds to step S290. Meanwhile, the load weight m2 is the upper limit threshold weight mMax If the value is not exceeded (No), the CPU of the information processing unit 60 returns this routine.

[0083] In step S290, the CPU of the information processing device 60 implements an alarm control to alert the operator of vehicle 1 to overloading, and then returns to this routine.

[0084] Although the weight measuring device, weight measuring method, and program according to this embodiment have been described above, this disclosure is not limited to the above embodiments, and various modifications are possible without departing from the purpose of this disclosure.

[0085] For example, in the above embodiment, the case where the effect of gradient resistance is considered was illustrated, but the effects of rolling resistance, air resistance, acceleration resistance, etc., which can be obtained from known mathematical formulas, may also be considered. Furthermore, in the above embodiment, the load weight m2 was explained as being calculated when the driving force F2 when loaded is the same as or approximately the same as the pre-stored unloaded driving force F1, but the average of multiple pre-calculated unloaded weights m1 is used as the unloaded weight m of the vehicle 1. 1_Ave Assuming that the driving force F2 under load is divided by the acceleration A2 under load (i.e., the total weight), then the unloaded weight m 1_Ave By subtracting this, the weight of the load in m2 (= F2 / A2-m 1_Ave ) may also be calculated. Furthermore, the calculation of the load weight m2 is not limited to driving scenes in which vehicle 1 accelerates or decelerates. For example, if vehicle 1 is a hydraulic excavator, it is also possible to configure the system to measure the weight of the excavated material by calculating the acceleration and driving force when the upper rotating body is rotated with the excavated material in the bucket.

[0086] Furthermore, although the above embodiment was described as being driven by an operator in the cabin 8, the technology of this disclosure can also be applied to vehicles that are driven by remote control or automatic control. In addition, the object of measurement is not limited to the weight of the load in m2, but may also be other weights related to the vehicle 1, such as the total weight or empty weight of the vehicle 1. Moreover, the technology of this disclosure is not limited to measuring the weight of construction machinery, but can be broadly applied to measuring the weight of other devices and machines driven by hydraulic motors. [Explanation of symbols]

[0087] 1...Vehicle, 2...Lower running body, 3...Drive wheels, 4...Idle wheels, 5...Crawler, 6...Upper rotating body, 7...Vessel (cargo bed), 8...Cabin, 10, 20, 30...Drive system, E...Engine, P...Hydraulic pump, MT...Hydraulic motor, RG...Reduction mechanism, 50...Weight measuring device, 60...Information processing device, 70...Vehicle status acquisition device, 71...Vehicle speed sensor (acceleration acquisition means), 72...Accelerator sensor, 73...Brake sensor, 74...First supply hydraulic sensor S (pressure difference acquisition means), 75... Second supply hydraulic pressure sensor (pressure difference acquisition means), 76... Discharge hydraulic pressure sensor (pressure difference acquisition means), 100... Acceleration calculation unit (acceleration acquisition means), 110... Pressure difference calculation unit (pressure difference acquisition means), 120... Drive force calculation unit (drive force calculation means), 130... Unloaded calculation processing unit (weight calculation means), 135... Unloaded calculated value storage unit (storage means), 140... Loaded calculation processing unit (weight calculation means), 150... Alarm control unit 150

Claims

1. A weight measuring device for a vehicle that is powered by a hydraulic motor, Acceleration acquisition means for acquiring the acceleration of the vehicle, A pressure difference acquisition means for acquiring the pressure difference between the hydraulic pressure supplied to the hydraulic motor and the hydraulic pressure discharged from the hydraulic motor, A driving force calculation means calculates the driving force of the vehicle based on the pressure difference obtained by the pressure difference acquisition means, The system includes a weight calculation means that calculates the weight of the vehicle based on the acceleration acquired by the acceleration acquisition means and the driving force calculated by the driving force calculation means. A weight measuring device characterized by the following features.

2. A weight measuring device according to claim 1, The aforementioned vehicle is a transport vehicle equipped with a cargo bed, The driving force calculation means calculates a first driving force, which is the driving force of the vehicle in an unloaded state, based on the pressure difference acquired by the pressure difference acquisition means when a first specific condition is met in which the vehicle accelerates or decelerates in an unloaded state with no cargo loaded on the cargo bed, and calculates a second driving force, which is the driving force of the vehicle in a loaded state, based on the pressure difference acquired by the pressure difference acquisition means when a second specific condition is met in which the vehicle accelerates or decelerates in a loaded state with cargo loaded on the cargo bed. The weight calculation means calculates the weight of the load loaded on the cargo bed based on a first acceleration, which is the acceleration in an unloaded state acquired by the acceleration acquisition means when the first specific condition is met; a second acceleration, which is the acceleration in a loaded state acquired by the acceleration acquisition means when the second specific condition is met; the first driving force; and the second driving force. A weight measuring device characterized by the following features.

3. A weight measuring device according to claim 2, The weight calculation means calculates a first weight, which is the weight of the vehicle in the unloaded state, based on the first acceleration and the first driving force. The system further comprises a storage means for storing the first acceleration, the first driving force, and the first weight, The weight calculation means calculates the weight of the load by dividing the value obtained by multiplying the first weight by the difference between the second driving force calculated by the driving force calculation means when the second specific condition is met and the first driving force stored in the storage means by a predetermined value or less. A weight measuring device characterized by the following features.

4. A weight measuring device according to claim 2, The first specific condition is met when the vehicle stops, unloads its cargo from the cargo bed, and then accelerates to start moving. The second specific condition is met when the vehicle stops, loads cargo onto the cargo bed, and then accelerates to start moving. A weight measuring device characterized by the following features.

5. A weight measuring device according to claim 2, The first specific condition is met when the vehicle accelerates or decelerates on a path moving from a designated loading area to a designated unloading area. The second specific condition is met when the vehicle accelerates or decelerates while moving along a path from a designated unloading location to a designated loading location. A weight measuring device characterized by the following features.

6. A method for measuring the weight of a vehicle that is driven by a hydraulic motor, The acceleration of the aforementioned vehicle is obtained, The pressure difference between the hydraulic pressure supplied to the hydraulic motor and the hydraulic pressure discharged from the hydraulic motor is obtained. Based on the acquired pressure difference, the driving force of the vehicle is calculated. Based on the acquired acceleration and the calculated driving force, the weight of the vehicle is calculated. A method for measuring weight characterized by the following features.

7. The computer in the weight measuring device of a vehicle that is powered by a hydraulic motor, The process of obtaining the acceleration of the aforementioned vehicle, A process for obtaining the pressure difference between the hydraulic pressure supplied to the hydraulic motor and the hydraulic pressure discharged from the hydraulic motor, A process to calculate the driving force of the vehicle based on the acquired pressure difference, The system executes a process to calculate the weight of the vehicle based on the acquired acceleration and the calculated driving force. A program characterized by the following features.

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