Calibration method and calibration system

Abstract

To provide a calibration method and a calibration system capable of simplifying calibration of a vehicle-mounted type load detection device (so-called dead weight meter).SOLUTION: The method includes a step of acquiring the gains 1n to a4 of the respective sensor units 10 from a mathematical optimizing solver by inputting, to the mathematical optimizing solver, a plurality of equations representing a relationship between a sum of products of the load signals ε a1 to ε a4 and the gains to a4 of the respective sensor units 10 and the actual weight M of the heavy object, the plurality of equations being obtained by loading the heavy object on the car 1 a plurality of times, and a step of calibrating the automatic load meter 20 using the gains a1 to acquired from the mathematical optimizing solver. 4n a1.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a calibration method and a calibration system. [Background technology]

[0002] Generally, when a vehicle used to transport goods is operated with a load exceeding the permitted weight (i.e., overloaded), it not only leads to traffic accidents such as rollovers and poor braking performance, but also contributes to the deterioration of the vehicle and damage to the road surface. For this reason, the load weight on the loading platform is legally limited and mandated by vehicle operation regulations.

[0003] Traditionally, the load weight of a cargo vehicle has been measured by placing the vehicle on a platform scale known as a kankan (weight scale). However, this method requires high equipment costs and a large installation space. For this reason, in recent years, load weight measurement devices (so-called weight scales) that are mounted on the vehicle itself to measure the load weight have been developed. This type of weight scale has weight measurement sensors, such as strain gauge sensors, attached to both the left and right ends of the front and rear axles, and measures the load weight by summing the outputs of these sensors, which are proportional to the loads acting on each of the front, rear, and left tires. Such on-board weight scales require regular inspection and calibration to maintain accuracy.

[0004] Patent Document 1 discloses a weight meter that is mounted on a vehicle and measures the load weight based on weight data from a sensor that changes depending on the amount of strain on the axle when a load is placed on the vehicle. In the weight meter of Patent Document 1, during calibration, the vehicle is placed on a mat scale that measures the vehicle weight, and the vehicle is jacked up with a jack to reduce the vehicle weight on the mat scale to a desired reduction amount, and the weight data output from the sensor when the desired reduction amount is reached is compared with reference weight data to display calibration information, and the weight meter is calibrated based on the calibration information. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-198176 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the calibration method disclosed in Patent Document 1 requires the placement of a mat scale when performing calibration, which requires a large installation space. Furthermore, the vehicle must be jacked up while measuring the amount of vehicle weight loss on the mat scale, which places a burden on the worker and takes a long time to complete the work.

[0007] Furthermore, in the calibration method disclosed in Patent Document 1, the vehicle is jacked up by supporting it at one point at the center of the axle, so the moment applied to the sensor changes depending on the sensor's installation position. In particular, the closer the sensor is installed to the center of the axle, the more different the distortion will be from that during normal loading and unloading, making it impossible to obtain accurate calibration results.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a calibration method and a calibration system that can simplify the calibration of a vehicle-mounted load detection device (so-called weight meter). [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, a calibration method according to the present invention comprises: A calibration method for calibrating a weight meter that measures the loaded weight of a vehicle based on load signals output from a plurality of sensors in response to strain of an axle caused by a load applied to the vehicle being transmitted to the axle, comprising: a step of inputting a plurality of equations representing the relationship between the sum of the products of the load signals and gains for each of the sensors, which are obtained by loading a heavy object of a predetermined weight onto the vehicle a plurality of times, into a mathematical optimization solver to calculate the gains of each of the plurality of sensors, and acquiring the gains of each of the plurality of sensors from the mathematical optimization solver; calibrating the weight scale using the gains of the plurality of sensors obtained from the mathematical optimization solver; It is a calibration method.

[0010] In order to achieve the above-mentioned object, a calibration method according to the present invention includes: A calibration method for calibrating a weight meter that measures the loaded weight of a vehicle based on load signals output from a plurality of sensors in response to strain of an axle caused by a load applied to the vehicle being transmitted to the axle, comprising: a step of loading a predetermined weight of heavy objects at a plurality of locations on the vehicle and recording the load signals output by the plurality of sensors; creating an equation representing the relationship between the sum of the products of the load signals and gains for each of the sensors and the predetermined weight for each of the heavy object loading positions; and inputting the created equation into a mathematical optimization solver to calculate the gains of the plurality of sensors, and calibrating the weight meter using the gains of the plurality of sensors obtained from the mathematical optimization solver. It is a calibration method.

[0011] In order to achieve the above-mentioned object, a calibration system according to the present invention comprises: A calibration system for calibrating a weight meter that measures the load weight of a vehicle based on load signals output from a plurality of sensors in response to strain on an axle caused by a load applied to the vehicle being transmitted to the axle, an acquisition unit for acquiring the load signals for each of the sensors obtained by loading a heavy object of a predetermined weight onto the vehicle multiple times; a control means for inputting a plurality of equations representing the relationship between the sum of the products of the load signals and gains for each of the sensors and the predetermined weight into a mathematical optimization solver to calculate the gains of the plurality of sensors, and acquiring the gains of the plurality of sensors from the mathematical optimization solver; the control means calibrates the weight meter using the gains of the plurality of sensors obtained from the mathematical optimization solver. It is a calibration system. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a calibration method and a calibration system that can simplify the calibration of a vehicle-mounted load detection device (a so-called weight meter).

[0013] The present invention has been briefly described above. The details of the present invention will become clearer by reading the following detailed description of the invention (hereinafter referred to as "embodiments") with reference to the accompanying drawings. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a calibration system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of the sensor unit. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of a weight meter. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of a calibration support device. [Figure 5] FIG. 5 is a flowchart illustrating an example calibration method according to one embodiment of the present invention. [Figure 6] FIG. 6 is a schematic diagram showing an example of loading a heavy object onto a vehicle. [Figure 7] FIG. 7 is a diagram showing an equation representing the relationship between the sum of the products of the load signals and gains for each sensor unit for each loading position of the heavy object, and the actual weight of the heavy object. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a calibration method and a calibration system for a vehicle load weight measuring device (so-called weight meter) according to one embodiment of the present invention will be described with reference to the drawings.

[0016] The present invention is not limited to the embodiments described below, and can be appropriately modified, improved, etc. In addition, the material, shape, size, number, location, etc. of each component in the embodiments described below are arbitrary and not limited as long as they can achieve the present invention.

[0017] <Calibration System 100> First, an example of a calibration system 100 will be described. As shown in Fig. 1, the calibration system 100 is configured to include a plurality of sensor units 10 provided near both left and right tires 3, 3 on both front and rear axles 2 of a vehicle 1, a weight meter 20 mounted on the vehicle 1 to measure and display the loaded weight of the vehicle 1 based on weight signals from the plurality of sensor units 10 (and a correction value, which will be described later), and a calibration support device 30 that supports the calibration of the weight meter 20.

[0018] In this example, the vehicle is assumed to have four wheels, so the calibration system 100 is made up of four sensor units 10, but if the vehicle has six wheels, the optimal form can be adopted, such as six sensor units 10.

[0019] In the calibration system 100, springs (e.g., leaf springs, not shown) are interposed between the left and right ends of both the front and rear axles 2 of the vehicle 1 and the front, rear, left and right locations of the vehicle frame (e.g., a cargo bed frame, not shown), and each of the sensor units 10 provided on the front and rear axles 2 outputs a load signal corresponding to the amount of strain on the axle 2 caused when the load applied to the vehicle 1 is transmitted to the axle 2 via the spring.

[0020] The vehicle 1 is a cargo transport vehicle such as a compactor truck or a truck, and when the vehicle 1 stops at a predetermined location, workers load and unload cargo onto the loading platform or the like (not shown) of the vehicle 1.

[0021] [Sensor unit 10] The sensor unit 10 is, for example, a known one, and outputs a load signal according to the amount of strain on the axle 2 as described above. As shown in Fig. 2, the sensor unit 10 is configured to include a sensor 11, an adjustment unit 12, a voltage / frequency conversion unit 13 (hereinafter also referred to as "V / F conversion unit 13"), a weight meter connector 14, and a setting connector 15. In the sensor unit 10, an ASIC is used for the adjustment unit 12.

[0022] The sensor 11 is a strain-type sensor that outputs a load signal according to the amount of strain on the axle 2. The adjustment unit 12 has the function of amplifying and correcting the load signal output by the sensor 11. The adjustment unit 12 is configured to have, for example, an A / D conversion unit that converts the load signal input from the sensor 11 into a digital load signal, a correction unit that corrects the digital load signal, an amplification unit that amplifies the digital load signal, and a D / A conversion unit that converts the digital load signal into an analog load signal. In this example, the adjustment unit 12 is realized by an ASIC, but the present invention is not limited to this and various other embodiments such as a DSP or a CPU can be used.

[0023] The V / F conversion unit 13 has a function of converting the load signal (voltage) adjusted by the adjustment unit 12 into a frequency. The weight meter connector 14 is connected to the weight meter 20 and has a function of transmitting the load signal converted into a frequency by the V / F conversion unit 13 to the weight meter 20. The setting connector 15 enables connection to a setting device (not shown) and is connected to the setting device when setting the sensor unit 10.

[0024] [Weight scale 20] The weight meter 20 measures and displays the load weight of the vehicle 1 based on preset gains a1 to a4 of the sensor unit 10 and the load signal from the sensor unit 10. As shown in FIG. 3 , the weight meter 20 includes a control unit 21, a display unit 22, an input unit 23, a communication unit 24, and a storage unit 25.

[0025] The control unit 21 has the function of measuring the load weight of the vehicle 1 based on the preset gains a1 to a4 of the sensor unit 10 and the load signal output by the sensor unit 10 in accordance with the amount of strain on the axle 2 caused when the load applied to the vehicle 1 is transmitted to the axle 2.

[0026] The display unit 22 has a function of displaying the load weight of the vehicle 1 measured by the control unit 21. The input unit 23 has a measurement start button (not shown), a measurement end button (not shown), etc., and can perform input related to the operation and operation control of the weight meter 20. The communication unit 24 is realized by, for example, an NIC, and is connected to a network by wire or wirelessly, so that information can be sent and received between the calibration support device 30, etc. via the network. The memory unit 25 stores gains a1 to a4, etc. of each sensor unit 10 used to measure the load weight of the vehicle 1.

[0027] [Calibration support device 30] The calibration support device 30 calculates gains a1 to a4 of each sensor unit 10 and calibrates the weight scale 20 using the calculated gains a1 to a4. As shown in Fig. 4, the calibration support device 30 is configured to include a measurement unit 31, a control unit 32, a display unit 33, an input unit 34, a communication unit 35, and a storage unit 36. Note that the calibration support device 30 can be configured, for example, from a measuring instrument and a terminal such as a PC (Personal Computer) or a tablet by dividing each function described below into separate units.

[0028] When a predetermined weight of heavy objects is loaded at each of a plurality of locations on the vehicle 1 during calibration of the weight meter 20 as described later, the measurement unit 31 measures the load signals ε output from the sensor units 10 in response to the strain of the axle 2 caused by the load applied to the vehicle 1 being transmitted to the axle 2. 1n ~ε 4n It has functions such as acquiring and recording data.

[0029] The control unit 32 receives the load signal ε 1n ~ε 4n The following equation 1 is created, which expresses the relationship between the sum of the products of (n is the number of loadings) and the gains a1 to a4, and the actual weight of the heavy object (corresponding to the "predetermined weight" of the present invention). Note that the following equation 1 is an example in which the vehicle 1 has two axles and four sensor units 10 (four variables).

[0030]

number

[0031] Furthermore, the control unit 32 has a function of inputting the created Equation 1 into a mathematical optimization solver and causing the mathematical optimization solver to calculate the gains a1 to a4 of each sensor unit 10. Here, the mathematical optimization solver is a general solver, such as a program executed by the control unit 32. In this example, the control unit 32 causes the mathematical optimization solver to calculate the gains a1 to a4 so that the measured weight M' when a heavy object is loaded on the vehicle 1 approaches the actual weight M. Note that the calculation of the gains a1 to a4 is preferably performed so that the measured weight M' coincides with the actual weight M, but may also be performed so that they correspond to predetermined values ​​desired by the owner of the vehicle 1.

[0032] Therefore, the control unit 32 calibrates the weight meter 20 using the gains a1 to a4 calculated by the mathematical optimization solver in this manner.

[0033] The display unit 33 has a function of displaying various information under the control of the control unit 32. The input unit 34 has a function of inputting various information through operation by an operator or the like. The communication unit 35 has a function of transmitting and receiving various information to and from the weight meter 20, for example, via a network. The memory unit 36 ​​stores various desired information.

[0034] <Calibration method> Next, an example of a calibration method will be described with reference to Fig. 5. This calibration method calculates gains a1 to a4 of the sensor unit 10 and uses the calculated gains a1 to a4 to calibrate the weight meter 20. In this calibration method, for example, a worker in charge of calibrating the weight meter 20 loads heavy objects onto the vehicle 1 multiple times while changing the loading position of the heavy objects (i.e., heavy objects are loaded at multiple locations on the vehicle 1), and calculates the gains a1 to a4 of each sensor unit 10 based on measurement results obtained as shown in Fig. 6.

[0035] After the vehicle 1 equipped with the weight meter 20 moves and stops at a predetermined position, the weight meter 20 and the calibration support device 30 are connected via the communication units 24, 35 when the vehicle 1 detects that it has stopped or when a predetermined operation is performed. Also, for example, each sensor unit 10 and the calibration support device 30 are connected via the setting connector 15 and the measurement unit 31. Then, for example, when an operator operates the input unit 34, the control unit 32 detects measurement start information (Sp1).

[0036] Then, a worker loads a heavy object onto the vehicle 1 by manual or mechanical work. Then, the measurement unit 31 receives a load signal ε 1n ~ε 4n and obtain the load signal ε 1n ~ε 4n Record (Sp2).

[0037] After Sp2, when the worker changes the loading position of the heavy object as shown in FIG. 6, the control unit 32 receives the load signal ε 1n ~ε 4nThe change in the loading position of the heavy object is detected from the change in the load signal ε 1n ~ε 4n Then, the measurement unit 31 receives a load signal ε from each sensor unit 10. 1n ~ε 4n and obtain the load signal ε 1n ~ε 4n Record (Sp3).

[0038] The control unit 32 determines whether the number of times heavy objects have been loaded has reached the required number (Sp4). If the number of times heavy objects have been loaded has reached the required number (Yes in Sp4), the control unit 32 proceeds to Sp5. On the other hand, if the number of times heavy objects have been loaded has not reached the required number (No in Sp4), the control unit 32 proceeds to Sp3. This required number may be set to correspond to the number of sensor units 10 (i.e., variables). When the required number is set to correspond to the number of sensor units 10 (i.e., variables), a two-axle vehicle is provided with four sensor units 10, so the required number is four, and a three-axle vehicle is provided with six sensor units 10, so the required number is six. Furthermore, since the accuracy of the calculated gains a1 to a4 improves as the number of equations input to the mathematical optimization solver increases, a desired number may be set as the required number.

[0039] The control unit 32 executes the mathematical optimization solver (Sp6). More specifically, the control unit 32 creates the above-mentioned Equation 1 for each loading position of the heavy object (see FIG. 7), inputs the created Equation 1 to the mathematical optimization solver, causes the mathematical optimization solver to calculate the gains a1 to a4 of each sensor unit 10, and acquires the calculated gains a1 to a4 from the mathematical optimization solver.

[0040] The control unit 32 sets the gains a1 to a4 acquired in Sp5 to the weight meter 20 (Sp6). As described above, the weight meter 20 sets the gains a1 to a4 of the sensor unit 10 that have been set in advance and the load signal ε 1n ~ε 4nBased on the above, the loaded weight of the vehicle 1 is measured. That is, the calculated gains a1 to a4 are set in the weight meter 20, and the calibration of the weight meter 20 is completed.

[0041] <Actions and Effects> As described above, according to this embodiment, the above equation (1) is input into a mathematical optimization solver, the gains a1 to a4 of each sensor unit 10 are obtained from the mathematical optimization solver, and the obtained gains a1 to a4 are used to calibrate the weight scale 20. This eliminates the need for special equipment such as a mat scale or adding weights during calibration, as was conventionally required, and also eliminates the need for a large work space. In other words, this configuration simplifies the calibration of the weight scale 20.

[0042] Furthermore, according to this embodiment, when accuracy is not a priority, the weight meter 20 can be calibrated in a short time by setting the required number of times to a small number.

[0043] Furthermore, according to this embodiment, by increasing the number of loading times, that is, by increasing the number of equations input to the mathematical optimization solver, the accuracy of the calculated gains a1 to a4 can be improved.

[0044] Furthermore, according to this embodiment, by loading a heavy load at a location where a load can actually be loaded when the vehicle 1 is in operation, highly accurate calibration results can be obtained.

[0045] <Additional Notes> Here, the features of the embodiments of the calibration method and calibration system according to the present invention described above will be briefly summarized and listed below in [1] to [3].

[0046] [1] A calibration method for calibrating a weight meter (e.g., 20) that measures the load weight of a vehicle (e.g., 1) based on load signals output from multiple sensors (e.g., 10, 11) in response to strain on an axle (e.g., 2) caused by a load applied to the vehicle (e.g., 1), the method comprising: The load signal (for example, ε 1n ~ε 4n a step of inputting a plurality of equations that express the relationship between the sum of products of the weights (e.g., a1 to a4) and gains (e.g., a1 to a4) and the predetermined weight (e.g., M) into a mathematical optimization solver to calculate the gains of the plurality of sensors, and acquiring the gains of the plurality of sensors from the mathematical optimization solver; calibrating the weight scale using the gains of the plurality of sensors obtained from the mathematical optimization solver; Calibration method.

[0047] [2] A calibration method for calibrating a weight meter (e.g., 20) that measures the load weight of a vehicle (e.g., 1) based on load signals output from multiple sensors (e.g., 10, 11) in response to strain on an axle (e.g., 2) caused by a load applied to the vehicle (e.g., 1), the method comprising: A predetermined weight of heavy objects is loaded at each of a plurality of positions on the vehicle, and the load signals (for example, ε 1n ~ε 4n ) and creating an equation (e.g., Equation 1) that expresses the relationship between the sum of the products of the load signals and gains (e.g., a1 to a4) for each of the sensors and the predetermined weight (e.g., M) for each of the heavy object loading positions; and inputting the created equation into a mathematical optimization solver to calculate the gains of the plurality of sensors, and calibrating the weight meter using the gains of the plurality of sensors obtained from the mathematical optimization solver. Calibration method.

[0048] [3] A calibration system (e.g., 100) for calibrating a weight meter (e.g., 20) that measures the load of a vehicle (e.g., 1) based on load signals output from a plurality of sensors (e.g., 10, 11) in response to strain on an axle (e.g., 2) caused by a load applied to the vehicle being transmitted to the axle, the calibration system comprising: The load signals (e.g., ε 1n ~ε 4n ) acquisition means (e.g., 31) for acquiring; a control means (e.g., 32) that inputs a plurality of equations that represent the relationship between the sum of the products of the load signals and gains for each of the sensors and the predetermined weight into a mathematical optimization solver to calculate the gains of the plurality of sensors, and acquires the gains of the plurality of sensors from the mathematical optimization solver; the control means calibrates the weight meter using the gains of the plurality of sensors obtained from the mathematical optimization solver. Calibration system.

[0049] According to the configurations [1] to [3] above, multiple equations representing the relationship between the sum of the products of the load signals and gains for each sensor, obtained by loading a heavy object of a predetermined weight onto a vehicle multiple times, and the predetermined weight, are input into a mathematical optimization solver, and the gains of each of the multiple sensors are obtained from the mathematical optimization solver, and the obtained gains are used to calibrate the weight scale. This eliminates the need for special equipment such as a mat scale or the need to add weights during calibration, as was previously required, and also eliminates the need for a large work space. In other words, this configuration simplifies the calibration of the weight scale. [Explanation of symbols]

[0050] 1 vehicle 2 axles 10 Sensor Unit 11 Sensors 20 Weight scale 30 Calibration support equipment 31 Measuring part 32 Control section 100 Calibration System a1~a4 gain M Actual weight ε 1n ~ε 4n Load Signal

Claims

1. A calibration method for calibrating a weight meter that measures the loaded weight of a vehicle based on load signals output from a plurality of sensors in response to strain of an axle caused by a load applied to the vehicle being transmitted to the axle, comprising: a step of inputting a plurality of equations representing the relationship between the sum of the products of the load signals and gains for each of the sensors, which are obtained by loading a heavy object of a predetermined weight onto the vehicle a plurality of times, into a mathematical optimization solver to calculate the gains of each of the plurality of sensors, and acquiring the gains of each of the plurality of sensors from the mathematical optimization solver; calibrating the weight scale using the gains of the plurality of sensors obtained from the mathematical optimization solver; Calibration method.

2. A calibration method for calibrating a weight meter that measures the loaded weight of a vehicle based on load signals output from a plurality of sensors in response to strain of an axle caused by a load applied to the vehicle being transmitted to the axle, comprising: a step of loading a predetermined weight of heavy objects at a plurality of locations on the vehicle and recording the load signals output by the plurality of sensors; creating an equation representing the relationship between the sum of the products of the load signals and gains for each of the sensors and the predetermined weight for each of the heavy object loading positions; and inputting the created equation into a mathematical optimization solver to calculate the gains of the plurality of sensors, and calibrating the weight meter using the gains of the plurality of sensors obtained from the mathematical optimization solver. Calibration method.

3. A calibration system for calibrating a weight meter that measures the load weight of a vehicle based on load signals output from a plurality of sensors in response to strain on an axle caused by a load applied to the vehicle being transmitted to the axle, an acquisition unit for acquiring the load signals for each of the sensors obtained by loading a heavy object of a predetermined weight onto the vehicle multiple times; a control means for inputting a plurality of equations representing the relationship between the sum of the products of the load signals and gains for each of the sensors and the predetermined weight into a mathematical optimization solver to calculate the gains of the plurality of sensors, and acquiring the gains of the plurality of sensors from the mathematical optimization solver; the control means calibrates the weight meter using the gains of the plurality of sensors obtained from the mathematical optimization solver. Calibration system.

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