KR100653737B1 - Method and apparatus for measuring the load weight of the vehicle - Google Patents

Abstract

A method and an apparatus for measuring a load of vehicle are provided to correct an axle value of the vehicle, computed by measuring a pressure of air spring, by using an error correction value previously formed by measuring a sensor value of related environment. In a sensor, one side of a cylinder unit is connected to an air spring(21) of a vehicle. A moving unit made of magnetic substance moves along the cylinder unit by a pressure of air from the air spring. A position measurement unit measures a position of the moving unit by using a variation of magnetic field emitted from the moving unit. A pressure measurement unit mounted on one end of the cylinder unit measures an air pressure of space with the moving unit.

Description

Method and apparatus for measuring load of a vehicle {Method and apparatus for measuring the load weight of the vehicle}

1A is a diagram illustrating a method of measuring a load of a vehicle using a pressure sensor according to the prior art, and FIG. 1B is a graph illustrating a measurement error according to the prior art.

2 is a view for explaining a vehicle load measuring method according to a preferred embodiment of the present invention.

3A and 3B are views illustrating a configuration of the sensor unit of FIG. 2.

4A and 4B are views for explaining a position measuring method of a sensor unit.

5A and 5B are diagrams illustrating a position measuring method according to a change in a magnetic field, and FIG. 5C is a graph showing a relationship between a distance change and a magnetic flux change.

6 is a block diagram showing the structure of a vehicle load measuring apparatus according to preferred embodiments of the present invention.

7 is a flowchart illustrating a vehicle load measuring method according to a preferred embodiment of the present invention.

8 is a diagram illustrating a suspension device of a vehicle configured with an air spring.

FIG. 9 shows the results of measuring the load applied directly to the air spring itself when loading or loading the same load, and the strain according to the pressure of the air spring that may occur through the fixing pins and the shaft of the frame over time. It is a graph.

The present invention relates to a method and apparatus for measuring a load on a vehicle, and in particular, the present invention relates to a method and apparatus for measuring a load on a vehicle capable of minimizing a measurement error caused by an external environment.

The operation of overload vehicles can cause damage to roads and bridge structures, which can shorten the service life of the roads, increase maintenance costs and reduce the ability to control and brake due to heavy weights, which can cause large traffic accidents.

In addition, overload vehicles deteriorate the performance of the road, and thus reduce the capacity of the road, causing noise and vibration during operation, and also act as environmental pollution factors around the road due to exhaust gas emissions.

In order to prevent the damage of overloading, various methods of crackdown and measuring have been introduced. Most of these methods introduce a fixed load-bearing system that measures the weight of the vehicle by installing sensors on the floor of the roadway, and introduces private weighbridges in construction sites, logistics warehouses, and import and export ports where freight is frequent. .

However, due to the problems of budget and equipment operation, it is not spread all over the country, and most of the overload measurement methods currently introduced are performed at the weighing station far from the loading point.

The structural problem of the current weighing of the vehicle not only causes the damage of roads and structures due to overload during the movement of the freight vehicle, but also reloads the load after reloading the load measured from a remote weighing platform to the loading site. I have a problem that needs to be done.

Such structural problems occur frequently in ports and airports that are mainly for export, resulting in an increase in logistics costs, causing problems in violation of law in the intentional state of truckers, and damage to roads and structures.

As a device capable of measuring the weight of the vehicle according to the prior art, a system applied to a leaf spring type vehicle that measures the weight of the vehicle by attaching a strain gauge to the leaf spring and measuring the amount of deformation thereof, and the air pressure of the air spring It can be divided into a pressure system for measuring the weight of the vehicle by using, and a load cell system for measuring the weight of the vehicle by applying a load cell, and a hydraulic gauge system for measuring the weight of the loading box of the vehicle.

Most of the above-described methods for measuring the weight of the vehicle show a lot of difference in its principle and configuration, and are commonly used as separate systems. In particular, measurement systems using one sensor method currently apply air springs. Failure to properly measure the stock load and weight of a widespread cargo vehicle occurs.

Systems for measuring the pressure of the air spring according to the prior art as a method of measuring the weight of the vehicle using a pressure sensor of the pressure sensor is changed by the air pressure by installing a pressure sensor in the air inlet of the air spring.

1 is a view for explaining a method of measuring the load of a vehicle using a pressure sensor according to the prior art. 1, reference numeral 1 denotes an air spring, 2 denotes an axle, 3 denotes a compressed air inlet, 4 denotes a T-type connector, 5 denotes a pressure sensor, and 6 denotes a signal line.

As shown in FIG. 1, in the conventional load measuring method, air is introduced into the T-type connector 4 from the air spring when the vehicle is loaded, and the pressure sensor part 5 connected to the T-type connector 4 is introduced. Measures the air pressure in the pressure sensor part changed due to the supplied air and transmits a signal to the external controller through the sensor cable 6, and the controller uses a method of calculating the load of the vehicle in proportion to the measured value of the pressure sensor. have.

However, this air spring method is very sensitive to the characteristics of the suspension, so the reaction rate is slow, and errors due to seasonal temperature change occur, and the method of changing the set value in the program is adopted to compensate for this. .

For example, when the temperature difference outside the sensor unit is significant, such as summer and winter, this causes a change in volume of the air spring and the air inside the sensor unit, and this volume difference causes a pressure measurement error. The measurement error according to the prior art is shown in Figure 1b.

In addition, when the air pressure of the air spring of the vehicle is changed due to the vibration and external influence of the vehicle, a problem arises that the initial value of the system needs to be reset, which makes it difficult to calculate the exact weight of the vehicle and reduces the reliability of the system. Results.

The technical problem to be achieved by the present invention is to provide a method and apparatus for measuring a load of a vehicle capable of generating an accurate vehicle load value by correcting an error caused by a change in a conventional external environment.

In addition, the technical problem to be achieved by the present invention is to enable the driver of the freight vehicle or the load of the vehicle to know the load weight of the vehicle directly on the site, vehicle load measuring method that can improve the above-mentioned problems caused by overload And to provide an apparatus.

Sensor for use in the vehicle load measuring method and apparatus of the present invention for achieving the above technical problem, one side is a cylinder portion connected to the air spring of the vehicle; A moving part embodied as a magnetic material and moving along the cylinder part by the pressure of air introduced from the air spring; A position measuring unit measuring a position of the moving unit using a change in the magnetic field radiated from the moving unit; And a pressure measuring part installed at one end of the cylinder part and measuring air pressure between the moving part.

In addition, the above-described pressure measuring unit is sealed with the cylinder to block the air flow in the cylinder and the outside of the cylinder, the moving portion is in close contact with the inner surface of the cylinder portion is the air flow between the moving portion and the pressure measuring unit through the moving portion The position measuring unit described above may be installed on the side of the cylinder to measure the position of the moving unit moving along the cylinder according to the density of magnetic flux radiated from the moving unit and applied to the position measuring unit.

In addition, the above-described sensor may further include an elastic body between the moving unit and the pressure measuring unit for reducing the moving unit to a predetermined reference position as the pressure decreases.

On the other hand, the vehicle load measuring method of the present invention for achieving the above technical problem, one side is implemented by a cylinder portion, a magnetic body connected to the air spring of the vehicle, the movement along the cylinder portion by the pressure of the air flowing from the air spring A sensor including a position measuring unit for measuring the position of the moving unit by using a change in the magnetic field radiated from the moving unit, and a pressure measuring unit installed at one end of the cylinder unit and measuring air pressure between the moving unit. A method of measuring a load of a vehicle, the method comprising: (a) setting a reference value using measured values of an axial weight and a sensor at a time of tolerance and fullness of the vehicle; (b) measuring the position of the moving unit to generate an error correction value for a measurement error due to a change in environment outside the vehicle; (c) generating a pressure measurement by measuring a pressure of air between the moving part and the pressure measuring part due to the air flowing into the sensor from the air spring of the vehicle when the vehicle is loaded; (d) calculating the aberration value of the sensored axle using the pressure measurement; And (e) correcting the congratulations value using the error correction value.

In addition, the above-described step (a) is performed according to the pressure measurement value by using the difference between the axial weight at the time of full vehicle and the axial weight at the time of tolerance of the vehicle, the sensor value at the time of full vehicle parking and the sensor value at the time of full vehicle tolerance. A proportionality constant for determining the aberration value of the vehicle may be determined, and in the step (d), the aberration value may be calculated by multiplying the proportional constant by the pressure measurement value.

In addition, the above-described step (a) sets the position of the moving part at the time of tolerance of the vehicle as the reference position of the moving part, and (b) the positive error correction value or negative error according to the relative position of the moving part with respect to the reference position. A correction value can be generated.

In addition, in the step (b) described above, the position of the moving unit may be measured at a predetermined time period to generate a plurality of position measurement values, and an error correction value may be generated using the average value of the plurality of position measurement values.

In addition, in the above-described step (d), the load holding value may be calculated using the ratio of the impact energy and the friction release impact energy when the vehicle is loaded, and the static strain of the pressure due to the load in the stationary state. In addition, step (d) described above multiplies the load conversion factor by the result of multiplying the ratio and the static strain, and the step (a) described above refers to the axial weight and the shaft at the time of tolerance of the vehicle. The load conversion coefficient can be determined using the difference in weight, the difference between the pressure measurement value at full load and the pressure measurement value at tolerance.

In addition, the above-described step (a) is the air spring of the vehicle when applying a load while applying a shock to the vehicle in a state where the friction between the axle of the vehicle in which the sensor is installed and the fixing pin connecting the axle to the vehicle is released. From the dynamic strain of pressure, the frictional impact energy can be measured.

In addition, the step (d) described above is the air spring of the vehicle when the load is applied while impacting the vehicle in a state where friction exists between the axle of the vehicle in which the sensor is installed and the fixing pin connecting the axle to the vehicle. The impact energy at loading can be measured from the dynamic pressure strain of.

In addition, the above-described impact energy may be calculated by multiplying the difference between the maximum dynamic strain and the minimum dynamic strain of the pressure applied to the air spring by the load and the time from the load application time to the minimum dynamic strain, and the pressure measuring unit described above. Dynamic strain can be measured by generating pressure measurements at 20 to 200 time periods per second.

On the other hand, another vehicle load measuring method of the present invention for achieving the above-described technical problem, the load is applied while applying a shock to the vehicle in a state where the friction between the axle of the vehicle and the fixing pin connecting the axle to the vehicle is released. Measuring frictional impact energy from the dynamic pressure strain of the air spring of the vehicle; Measuring the static pressure strain of the air spring when applying a load, without impacting the vehicle in the presence of friction; Measuring impact energy upon loading from the dynamic pressure strain of the air spring when applying a load while impacting the vehicle in the presence of friction; Correcting the static pressure strain by using a ratio of impact energy and friction release impact energy at the time of loading; And calculating a thrust value of the vehicle by correcting the corrected static pressure strain by using an error correction value for a measurement error caused by an external environment change.

In addition, the above-described impact energy can be calculated by multiplying the difference between the maximum dynamic strain and the minimum dynamic strain of the pressure applied to the air spring by the load, and the time from the time of applying the load to the minimum dynamic strain.

In addition, the pressure strain is a cylinder portion one side is connected to the air spring; A moving part embodied as a magnetic material and moving along the cylinder part by the pressure of air introduced from the air spring; A position measuring unit measuring a position of the moving unit using a change in the magnetic field radiated from the moving unit; And a pressure measurement value measured from a sensor installed at one end of the cylinder part and including a pressure measuring part measuring an air pressure between the moving part, and an error correction value is changed in the position of the moving part due to a change in external environment. It can be determined according to.

On the other hand, the vehicle load measuring apparatus of the present invention for achieving the above-described technical problem is implemented by a cylinder portion, a magnetic body, one side is connected to the air spring of the vehicle, the moving portion moving along the cylinder portion by the pressure of the air flowing from the air spring A sensor unit including a position measuring unit measuring a position of the moving unit using a change in the magnetic field radiated from the moving unit, and a pressure measuring unit installed at one end of the cylinder unit and measuring air pressure between the moving unit; And generating an error correction value using the position measurement value input from the position measuring unit, calculating a weight value using the pressure measurement value input from the pressure measuring unit, and using the error correction value. The controller basically includes a controller for correcting an error of the busy value to generate a busy value of the vehicle.

In addition, the above-described vehicle load measuring apparatus may further include a signal amplifier for amplifying the position measurement value and the pressure measurement value, or may further include an A / D converter for converting the position measurement value and the pressure measurement value, which are analog signals, into a digital signal. Can be.

The position measuring unit may further include a high speed calculating unit which generates a plurality of position measuring values at predetermined time periods, calculates and outputs an average value of the plurality of position measuring values, and the controller generates an error correction value using the average value. Can be.

In addition, the controller multiplies the pressure measured value by a proportional constant to calculate the axial value of the vehicle. And the ratio between the differences of the pressure measured values at the time of tolerance.

In addition, the error correction value may be a positive or negative value depending on the relative position of the moving part with respect to the reference position, based on the position of the moving part at the time of tolerance of the vehicle.

In addition, the control unit may calculate the load value using the ratio of the impact energy and friction release impact energy at the time of loading the vehicle and the static strain of the pressure due to the loading load in the stationary state, and the controller multiplies the ratio by the static strain The resultant weight is multiplied by the load conversion factor to calculate the axial load value, and the load conversion factor is the difference between the axial weight at full load and the axial weight at tolerance, the pressure measured value at full load and the pressure at tolerance. It can be determined according to the ratio between the differences of the measured values.

In addition, the friction release impact energy is the maximum of the air spring of the vehicle when the load is applied while impacting the vehicle while the friction between the axle of the vehicle in which the sensor unit is installed and the fixing pin connecting the axle to the vehicle is released. It can be calculated by multiplying the difference between the dynamic pressure strain and the minimum dynamic pressure strain and the time to the minimum dynamic strain, and the impact energy is the friction between the axle of the vehicle with the sensor unit and the fixing pin connecting the axle to the vehicle. In the present state, when the load is applied while impacting the vehicle, it is calculated by multiplying the difference between the maximum dynamic pressure strain and the minimum dynamic pressure strain of the air spring of the vehicle and the time from the time of applying the load to the minimum dynamic strain. The pressure measuring unit may measure the dynamic strain by generating a pressure measurement at a time interval of 20 to 200 times per second.

Hereinafter, a sensor unit and a measuring process of the sensor unit used in preferred embodiments of the present invention will be described with reference to the accompanying drawings, and a method and apparatus for measuring a load of a vehicle using the measured values of the sensor unit will be described.

2 is a view for explaining a vehicle load measuring method according to a preferred embodiment of the present invention.

The present invention implements a sensor unit including a position sensor as well as a pressure sensor in order to correct a measurement error due to a change in the external environment, and uses a pressure measurement measured by the sensor unit and a position measurement value indicating a change in the external environment. Measure the load.

2, reference numeral 21 denotes an air spring, 22 denotes an axle, 23 denotes a compressed air inlet (for a left air spring and a right air spring), 24 a T-type connector, 25 a sensor part, and 26 a sensor. Signal lines connected to the negative pressure measuring unit and transmitting pressure measurement values to the control unit, and 27 represent signal lines connected to the position measuring unit of the sensor unit and transmitting the position measuring values to the control unit which will be described later.

3A and 3B are views illustrating a configuration of the sensor unit of FIG. 2.

3A is a diagram illustrating a configuration of a sensor unit in a measurement initial state. Referring to FIG. 3A, a sensor unit is formed of a cylinder part 25-1 and a magnetic material to move inside the cylinder part 25-1. (25-2), a position measuring unit (25-3) installed on one side of the cylinder portion 25-1 to detect the position of the moving portion 25-2, and one end of the cylinder portion 25-1 It is configured to include a pressure measuring section (25-4) installed in the to measure the air pressure between the moving portion (25-2).

At this time, the pressure measuring unit 25-4 is sealed together with the cylinder portion 25-1 to block the air from flowing out to the outside or the air from flowing from the outside to the inside, and the moving unit 25-2. Also in close contact with the cylinder portion 25-1, outside air flows between the moving portion 25-2 and the pressure measuring portion 25-4, or the moving portion 25-2 and the pressure measuring portion 25-4. To prevent air from leaking outside. In addition, the position measuring unit 25-3 is implemented as a Hall sensor, and generates and outputs a voltage value corresponding to a change in magnetic flux density applied to the position measuring unit 25-3.

In addition, the sensor unit is located in a space between the moving unit 25-2 and the pressure measuring unit 25-4 so that the moving unit 25-2 moves easily to an initial position as the pressure of the air spring decreases. It may further include an elastic body 25-5.

Meanwhile, as described above, the position signal line 27 outputting the position measurement value measured by the position measurement unit 25-3, and the pressure signal line outputting the pressure measurement value measured by the pressure measurement unit 25-4 ( 26 is connected to the sensor unit 25.

As shown in FIG. 3A, at the beginning of the measurement in which no load is applied to the vehicle, the moving part 25-2 is positioned in the middle of the cylinder part 25-1 so that the interior space of the cylinder part 25-1 is upper and The lower part is divided into two parts, at which time the upper pressure is P1 and the lower pressure is Pi. After that, when a load is applied to the vehicle and the air pressure increases in the air spring, air flows into the cylinder portion 25-1 through the T-shaped connector, and the pressure in the upper portion of the cylinder portion 25-1 is caused by the introduced air. This increases, which causes the moving part 25-2 to move downward.

When the moving part 25-2 moves downward, the volume of the lower part of the cylinder part 25-1 decreases, and the pressure increases. This change satisfies Equation 1 below.

PV = RT

In Equation 1, P denotes a pressure, V denotes a volume, R denotes a constant, and T denotes a temperature. Since RT has a fixed value at room temperature, when the volume of the lower part of the sensor is reduced, it can be seen that the pressure increases according to Equation 1 described above.

3B shows the state of the sensor section after the moving section 25-2 is moved. Referring to FIG. 3B, after the load is applied to the vehicle, the pressure in the upper portion of the cylinder portion 25-1 is changed from P1 to P2, and the lower pressure is changed from Pi to Pf, respectively.

In addition, when the load is removed, the pressure in the upper portion of the cylinder portion 25-1 is changed from P2 to P1, and the moving portion 25-2 is affected by the pressure as the pressure in the upper portion decreases (sensor portion 25). Is included in the elastic body 25-5, the restoring force of the elastic body acts together) to move upwards, so that the pressure in the lower portion of the cylinder portion 25-1 is changed back from Pf to Pi.

The pressure measuring unit 25-4 measures the pressure in the lower portion of the cylinder unit 25-1 in real time and outputs the pressure measurement value to a controller which will be described later. The controller measures the load of the vehicle using the pressure measurement value. . Since the method of outputting the measured value by measuring the pressure in the pressure measuring unit 25-4 is similar to the prior art, a detailed description thereof will be omitted.

On the other hand, as described above with respect to the prior art, the measured value of the pressure measuring unit 25-4, even when the same load is applied, an error occurs in the measured value according to the external environmental factors such as the season or the inclination of the vehicle. Can be.

In order to correct this error, the position measuring unit 25-3 of the sensor unit 25 of the present invention measures the position of the moving unit 25-2 and outputs the position measurement value to a controller which will be described later. The position measurement value is used to generate an error correction value to remove weight measurement errors that may be caused by external environmental factors such as vehicle shaking, tilting, or external temperature change.

4A and 4B are views for explaining a position measuring method of a sensor unit. First, a method of measuring the position of the moving unit 25-2 with reference to FIGS. 4A and 4B will be described. When the vehicle measures the weight of the vehicle on the weighing bridge in the tolerance state, the moving unit 25-2 of the sensor unit is measured. ) Is located approximately at the center of the position measuring unit 25-3 provided on the side of the cylinder portion 25-1, and sets it as the reference point d0.

After that, when the position of the moving unit 25-2 implemented as a magnetic body is changed to d1 or d2 according to an external environment change, the position measuring unit 25-3 is moved from the moving unit 25-2 to the position measuring unit. The position of the moving part 25-2 is measured according to the change of the magnetic field input to (25-3).

5A and 5B are diagrams illustrating a position measuring method according to a change in a magnetic field, and FIG. 5C is a graph showing a relationship between a distance change and a magnetic flux change. When the position of the moving unit 25-2, which is a magnetic body, is changed by an external environment, as shown in FIG. 5C, the moving unit 25-2 is generated by the moving unit 25-2 and applied to the position measuring unit 25-3 in proportion to the distance. The magnetic field density is changed, and the position measuring unit 25-3 converts the change in flux density into a voltage value according to Equation 2 below to convert the position measurement value for the position of the moving unit 25-2. Create

In Equation 2, Vhall represents an electromotive force (emf) in volts, B represents an applied magnetic flux density, and sigma is a constant representing an induced electromotive force per unit magnetic flux density.

Hereinafter, a vehicle load measuring method and apparatus according to exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 9.

6 is a block diagram showing the structure of a vehicle load measuring apparatus according to preferred embodiments of the present invention. Referring to FIG. 6, the vehicle load measuring apparatus according to the exemplary embodiments of the present invention includes a sensor group unit 600, a channel selector 610, a signal amplifier 620, an A / D converter 630, The high speed calculator 640, a controller 650, and a user output unit 660 are included.

The sensor group unit 600 is composed of the plurality of sensor units 25 described above, and each sensor unit 25 is installed on each axis of the vehicle one by one, and the pressure measured value measured for the load applied to the corresponding axis. And outputs the position measurement value to the channel selector 610.

The channel selector 610 selects the sensor units 25 one by one according to the control signal input from the controller 650, and outputs the position measurement value and the pressure measurement value input from the selected sensor unit 25 to the signal amplifier 620. )

The signal amplifier 620 amplifies the position measurement value and the pressure measurement value input from the channel selector 610 and outputs them to the A / D converter 630.

The A / D converter 630 converts the position measurement value and the pressure measurement value, which are analog signals, into a digital signal, and outputs the position measurement value to the high speed calculator 640, and outputs the pressure measurement value to the controller 650.

The high speed calculator 640 is implemented in an FPGA, and stores the input position measurement value in each memory bank for each channel, and performs a high-speed operation over a predetermined number of times (100 times in the preferred embodiment of the present invention) to perform an average value of the position measurement values. Output to the control unit 650.

The control unit 650 calculates the convection value of the axle in which the corresponding sensor is installed by using the pressure measurement value input from the A / D converter 630 for each channel. In addition, an error correction value is generated using the position measurement value input from the high speed calculating unit 640, and the value during celebration is corrected using the error correction value. In addition, the control unit 650 calculates the axial value of each axis, calculates the load of the entire vehicle, and outputs it to the user output unit 600.

The user output unit 660 displays the celebration value and the load value of the entire vehicle input from the control unit 650 to the user.

7 is a flowchart illustrating a vehicle load measuring method according to a preferred embodiment of the present invention. Referring to FIG. 7, in order to measure the load of the vehicle, first, a reference value is set in a tolerance state and a full state (S700).

In order to set the reference value, first, during the tolerance state, the axle of the vehicle is measured on the weighbridge, and the pressure sensor value and the position measurement value of each sensor unit at this time are measured (S702). Thereafter, a load is applied to the vehicle, and the axial load of the vehicle is measured at the weighbridge again in a full state, and the pressure sensor value and position measurement value of each sensor unit at this time are measured (S704).

When the step S700 is performed, the reference position d0 of the moving unit 25-2 is set in each sensor unit, and the control unit 650 is used to calculate the load of the vehicle proportionally using the pressure measurement value. The slope value of the proportional expression is determined (S706).

For example, assuming that the pressure measurement value is proportionally increased in accordance with the load of the vehicle, the axial weight value Y of the axle in which the sensor unit is installed is linearly proportional to the pressure measurement value X, so that Y It can be expressed by an expression such as = AX, and the proportional constant A at this time can be obtained by the following equation (3).

Thereafter, when a load is applied to the vehicle at different times and locations, an error correction value is generated to correct an error of the measured load value due to the changed external environment (S710).

Specifically, the position measuring unit 25-3 of each sensor unit 25 may have a predetermined time period (for example, a time period for selecting the corresponding sensor unit in the channel selector 610) for the predetermined number of times. According to the change in the magnetic flux density applied from the moving unit 25-2 to the position measuring unit 25-3 to a voltage value to generate a position measurement value (S712), the position measurement value of each sensor unit is sequentially After being output to the signal amplifier 620 through the channel selector 610 and amplified, the A / D converter 630 converts the digital signal to the high speed calculator 640 (S714).

The high speed operation unit 640 sequentially stores the position measurement values of each sensor unit 25 in an internal memory bank, and then generates an average value of the position measurement values of each of the stored sensor units 25 and the control unit 650. Output (S716). After receiving the plurality of position measurement values from the same sensor unit as described above and outputting them by averaging, the error of the position measurement value can be minimized.

On the other hand, the control unit 650 generates an error correction value B by using the average value of the input position measurement value (S718). The error correction value can be obtained by multiplying the average value of the position measurement value expressed in voltage by the proportional constant obtained by the above expression (3). At this time, when the position of the moving part 25-2 is located above the reference point d0 (d1), the air pressure between the moving part 25-2 and the pressure measuring part 25-4 is lower than the reference value. 2) If the position of the moving part 25-2 is located below the reference point d0 (d2), the air pressure is higher than the reference.

Therefore, in the case of ①, since the pressure applied to the pressure measuring unit 25-4 is lower than the reference value set in step S700, the pressure measuring unit 25-4 generates a pressure measuring value having a weight lower than the actual weight. As such, the controller 650 generates a positive error correction value. In addition, in the case of ②, since the pressure applied to the pressure measuring unit 25-4 appears higher than the set reference value, the pressure measuring unit 25-4 generates a pressure measurement value of a weight higher than the actual weight, so that the control unit 650 generates a negative error correction value.

On the other hand, when the generation of the error correction value for each sensor unit 25 is completed, the load is applied to the vehicle, the pressure measurement value measured as the load is applied in real time channel selector 610, signal amplification It is input to the control unit 650 via the unit 620 and the A / D conversion unit 630 (S720).

The control unit 650 calculates the value of the celebration of the vehicle shaft on which the sensor unit is installed, using the pressure measurement values input from the respective sensor units 25 (S730). Specifically, the control unit 650 in step S700 described above. Multiply the pressure measurement value (X) input to the proportionality constant A obtained by the equation (3) to generate the current convection value (Y). That is, the control unit 650 substitutes the pressure measurement value into the equation of Y = AX to generate the value during celebration.

Thereafter, the controller 650 generates the final axle value of the axle by correcting the calculated error of the axle value using the error correction value of the sensor unit, generates a total load value of the vehicle, and outputs it to the user. (S740). At this time, the controller 650 may generate a final congratulation value by adding the error correction value B generated in operation S710 to the congratulation value calculated in step S730.

As a result, the control unit 650 substitutes the pressure sensor value X and the error correction value B into the following Equation 4, calculates the axial load value Y provided with the sensor unit, and adds them to the total load value of the vehicle. Calculate

So far, a method and apparatus for measuring a load on a vehicle according to an exemplary embodiment of the present invention have been described. It will be appreciated by those skilled in the art that the application of this embodiment can drastically improve the error of the prior art vehicle measurement method.

However, even when the load measuring method according to the above-described embodiment exists, there is a slight measurement error, because the strain generated in the air spring appears differently depending on the state when loading the vehicle in the vehicle. This difference in strain is due to the friction between suspensions composed of air springs.

8 is a diagram illustrating a suspension device of a vehicle configured with an air spring. Referring to FIG. 8, when a load is applied to the frame 800 of the upper plate, the applied load is transmitted to the fixing pin 810 for each axis, and the change value of the air spring 820 due to the load is changed by the lever principle. Is generated.

As shown in FIG. 8, when a load is applied to the frame upper plate 800, frictional force is generated between the fixing pin 810 and each axle 830, and thus the strain caused by each air spring 820 is a load. An error is generated unlike when directly applied to the air spring 820.

FIG. 9 shows the results of measuring the load applied directly to the air spring itself when loading or loading the same load, and the strain according to the pressure of the air spring that may occur through the fixing pins and the shaft of the frame over time. It is a graph.

 Referring to FIG. 9, the change in pressure in an ideal state refers to a case in which a strain is obtained by applying a load without applying an impact by assuming that the air spring itself is not used by a fixing pin.

  Dynamic change in pressure means measuring the sampling interval at least 20 times per second (> 20 Hz) and measuring in more detail the distribution of pressure that is changed by the effect of an air spring vibrating by impact when loading cargo. It is attenuated by the pin friction of the pin and ultimately converges to the pressure value in the ideal state without friction and impact.

The static pressure change refers to the change in the pressure of the air spring when the load is loaded without impact in the presence of pin friction of the fixing pin, and the maximum strain is reached immediately by the load because the dynamic effect of the impact is not reflected. It can be seen that the decrease in the strain due to friction is measured somewhat less than the strain in the ideal state.

Looking at the strain at the time of loading in the ideal state of Figure 9, it can be seen that the pressure increases over time and is maintained at a constant size. In practice, however, the static strain measurement, that is, the static pressure change after the cargo has been loaded with the vehicle stationary on a flat surface, shows that, over time, it does not reach the ideal value. This is because the weight of the cargo loaded by friction between the fixing pins of the air spring is not accurately transmitted as the pressure change.

Therefore, static strain measurement alone underestimates the load due to cargo loading, so accurate measurement of load is not possible immediately, and this underestimation may cause a difference up to 5% or more of the actual weight, which is a great burden on the vehicle driver. Can be.

On the other hand, when loading the vehicle in consideration of the temporal change of the strain rate according to the impact can reflect the effect of the friction of the fixed pin of the air spring during loading, it is possible to accurately obtain the actual load.

Therefore, another preferred embodiment of the present invention calculates the congratulations in consideration of the influence of the fixing pin friction of the above-described embodiment. The present embodiment obtains the impact energy by dynamically measuring the change in pressure due to the weight of the cargo applied to the air spring of the vehicle when loading the cargo, this is an ideal state, that is, in the state that the fixing pin friction of the air spring is released Compensation for the static strain is compared with the impact energy of.

The impact energy applied to the air spring when loading the vehicle in the vehicle is a product of the dynamic strain ε _v shown in FIG. 9 and the time ΔT, which is expressed by Equation 5 below.

In Equation 5, the dynamic strain ε _v represents the difference between the maximum dynamic strain and the minimum dynamic strain, and the time ΔT represents the time from the time of applying the load to the first minimum dynamic strain, respectively.

At this time, the dynamic strain, that is, the dynamic pressure change over time is preferably measured in the range of 20 to 200 times per second, more preferably about 50 to 100 times per second.

If the friction release impact energy in the ideal state without friction of the fixed pin is calculated in advance, and the ratio with the impact energy at actual loading, the error of the strain in the static state can be estimated. By correcting the static strain by 6, the actual weight can be converted at the time of loading.

Here, α is the conversion factor during the celebration, and represents the same value as A obtained in step S700 of the above-described embodiment, and ε _s represents the strain due to the loading load in the stationary state.

First, in the above-described step S700, in the state where the friction between the fixed pin and the axle with the air spring is released, the dynamic strain is obtained by measuring the pressure at the time of applying the load while applying the impact. Equation 5 is used to obtain the impact energy of frictional release from the dynamic strain and stored inside.

In operation S700, the static strain may be obtained and stored therein by applying a load without impact in the state where the friction exists.

On the other hand, the conversion coefficient α during the celebration is obtained by the above equation (3).

Then, when the load is applied to the vehicle, in step S730 the pressure measuring unit 25-4 measures the pressure at least 20 times per second to output the dynamic strain of the vehicle at the time of loading, the control unit 650 described above Using the equation (4) to obtain the impact energy at the time of loading from the dynamic strain.

The controller 650 calculates the value of the celebration value according to Equation 6 described above, and corrects the error of the value of the celebration value by adding the error correction value to the calculated value of the celebration value in the same manner as in step S740 described above. The load values of the entire vehicle are generated by summing each of the sum values.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

As described so far, the vehicle load measuring method of the present invention sets a reference value in advance, and before generating a load on the vehicle at different times and locations, measures the sensor value of the environment and generates an error correction value in advance. By correcting the vehicle's center value calculated by measuring the pressure of the air spring using the error correction value, it is possible to accurately correct the error caused by the external environment change such as the change of temperature or the tilt of the vehicle. Therefore, the vehicle weight measuring method and apparatus of the present invention has an effect of higher accuracy, versatility, efficiency and reliability than the conventional vehicle load measuring system.

Claims (32)

A cylinder part of which one side is connected to the air spring of the vehicle; A moving part formed of a magnetic material and moving along the cylinder part by the pressure of air introduced from the air spring; A position measuring unit measuring a position of the moving unit by using a change in the magnetic field radiated from the moving unit; And And a pressure measuring part installed at one end of the cylinder part to measure air pressure between the moving part and the moving part. According to claim 1, wherein the pressure measuring unit The sensor is sealed with the cylinder portion, characterized in that for blocking the flow of air in the cylinder and the outside of the cylinder. The method of claim 1, wherein the moving unit The sensor is in close contact with the inner surface of the cylinder portion, characterized in that to block the flow of air between the moving portion and the pressure measuring unit through the moving portion. According to claim 1, wherein the position measuring unit And a sensor provided on the side of the cylinder and measuring the position of the moving portion moving along the cylinder according to the density of the magnetic flux radiated from the moving portion and applied to the position side government. The method of claim 1, And an elastic body for reducing the moving part to a predetermined reference position as the pressure decreases between the moving part and the pressure measuring part. One side is implemented by a cylinder portion, a magnetic body connected to the air spring of the vehicle, the moving portion moving along the cylinder portion by the pressure of the air flowing from the air spring, the movement using a change in the magnetic field radiated from the moving portion A method for measuring a load on a vehicle using a sensor provided at a position measuring unit for measuring a position of a negative portion, and a pressure measuring unit provided at one end of the cylinder portion and measuring air pressure between the moving portion, (a) setting a reference value by using the axial weight at the time of tolerance and fullness of the vehicle and measured values of the sensor; (b) measuring the position of the moving unit to generate an error correction value for a measurement error due to a change in environment outside the vehicle; (c) generating a pressure measurement by measuring a pressure of air between the moving part and the pressure measuring part due to the air flowing into the sensor from the air spring of the vehicle when the vehicle is loaded; (d) calculating the aberration value of the axle with the sensor using the pressure measurement value; And and (e) correcting the celebration value using the error correction value. The method of claim 6, wherein step (a) Determine the middle value of the vehicle according to the pressure measurement value by using the difference between the axial weight at the full load of the vehicle and the axial weight at the tolerance, and the difference between the sensor value at the full load and the sensor value at the full load Vehicle load measuring method, characterized in that for determining the proportional constant. Claim 8 was abandoned when the registration fee was paid. 8. The method of claim 7, wherein step (d) And multiplying the proportional constant by the pressure measurement value to calculate the aberration value. The method of claim 6, wherein step (a) And a position of the moving part at the time of tolerance of the vehicle as a reference position of the moving part. Claim 10 was abandoned upon payment of a setup registration fee. The method of claim 9, wherein step (b) The method of claim 6, wherein step (b) And measuring a position of the moving unit at a predetermined time period to generate a plurality of position measurement values, and generating the error correction value using an average value of the plurality of position measurement values. The method of claim 5, wherein step (d) And a load carrying capacity value is calculated by using a ratio of impact energy and friction release impact energy when the vehicle is loaded, and a static strain of pressure due to a load load in a stationary state. The method of claim 12, In step (d), multiplying the load conversion factor to a result of multiplying the ratio by the static strain, and calculating the loading load, In the step (a), the load conversion coefficient is calculated by using the difference between the axial weight at the full load and the axial weight at the tolerance, the pressure measured value at the full load and the pressure measured value at the full load of the vehicle. Vehicle load measuring method, characterized in that determined. The method of claim 12, wherein step (a) Dynamic strain of the air spring pressure of the vehicle when the load is applied while impacting the vehicle in a state where friction between the axle of the vehicle in which the sensor is installed and the fixing pin connecting the axle to the vehicle is released And measuring the frictional release impact energy from the vehicle load measurement method. The method of claim 12, wherein step (d) From the dynamic pressure strain of the air spring of the vehicle when the load is applied while impacting the vehicle in a state where there is friction between the axle of the vehicle where the sensor is installed and the fixing pin connecting the axle to the vehicle, Vehicle load measuring method characterized in that for measuring the impact energy at the time of loading. Claim 16 was abandoned upon payment of a setup registration fee. 16. The method of claim 12, wherein the impact energy is The vehicle load measuring method is calculated by multiplying the difference between the maximum dynamic strain and the minimum dynamic strain of the pressure applied to the air spring by the load and the time from the load application time to the minimum dynamic strain. Claim 17 was abandoned upon payment of a registration fee. The method of claim 16, wherein the pressure measuring unit And measuring the dynamic strain by generating pressure measurements at time intervals of 20 to 200 times per second. The friction energy is released from the dynamic pressure strain of the air spring of the vehicle when the load is applied while impacting the vehicle while the friction between the vehicle axle and the fixing pin connecting the axle to the vehicle is released. Measuring; Measuring a static pressure strain of the air spring when applying a load without impacting the vehicle in the presence of friction; Measuring impact energy upon loading from the dynamic pressure strain of the air spring when applying a load while impacting the vehicle in the presence of friction; Correcting the static pressure strain by using a ratio of the impact energy at the time of loading and the frictional release impact energy; And Compensating the corrected static pressure strain using the error correction value for the measurement error due to a change in the external environment to calculate the thrust value of the vehicle. 19. The method of claim 18, wherein the impact energy is The vehicle load measuring method is calculated by multiplying the difference between the maximum dynamic strain and the minimum dynamic strain of the pressure applied to the air spring by the load, and the time from the time of applying the load to the minimum dynamic strain. Claim 20 was abandoned upon payment of a registration fee. A cylinder part of which one side is connected to the air spring; A moving part formed of a magnetic material and moving along the cylinder part by the pressure of air introduced from the air spring; A position measuring unit measuring a position of the moving unit by using a change in the magnetic field radiated from the moving unit; And Is installed at one end of the cylinder portion, and measured using a pressure measurement value measured from a sensor including a pressure measuring unit for measuring the air pressure between the moving unit, The error correction value is a vehicle load measuring method, characterized in that determined according to the change in the position of the moving unit due to a change in the external environment. One side is implemented by a cylinder portion, a magnetic body connected to the air spring of the vehicle, the moving portion moving along the cylinder portion by the pressure of the air flowing from the air spring, the movement using a change in the magnetic field radiated from the moving portion A sensor unit including a position measuring unit measuring a position of the unit, and a pressure measuring unit installed at one end of the cylinder unit to measure air pressure between the moving unit; And Generates an error correction value using the position measurement value input from the position measuring unit, calculates a value during celebration using the pressure measurement value input from the pressure measuring unit, and changes the external environment using the error correction value. And a controller for correcting the error of the busy value due to the controller to generate a busy value of the vehicle. Claim 22 was abandoned upon payment of a registration fee. The method of claim 21, And a signal amplifier configured to amplify the position measurement value and the pressure measurement value. Claim 23 was abandoned upon payment of a set-up fee. The method of claim 21, And an A / D converter for converting the position measurement value and the pressure measurement value, which are analog signals, into digital signals. The method of claim 21, The position measuring unit may further include a high speed calculating unit which generates a plurality of position measuring values at predetermined time periods, and calculates and outputs an average value of the plurality of position measuring values. The control unit is a vehicle load measuring apparatus, characterized in that for generating the error correction value using the average value. Claim 25 was abandoned upon payment of a registration fee. The method of claim 21, wherein the control unit Multiplying the proportional constant by the pressure measurement value to calculate the aberration value of the vehicle, 25. The method of claim 21, wherein the error correction value is And a positive or negative value depending on the relative position of the moving part with respect to the reference position when the position of the moving part is referenced based on the tolerance of the vehicle. Claim 27 was abandoned upon payment of a registration fee. The method of claim 21, wherein the control unit And the load value is calculated using a ratio of impact energy and friction release impact energy when the vehicle is loaded, and a static strain of pressure due to a loading load in a stationary state. Claim 28 was abandoned upon payment of a registration fee. The method of claim 27, The control unit calculates the celebration weight value by multiplying the load conversion factor by a result of multiplying the ratio by the static strain. The load conversion coefficient is determined according to the ratio between the difference between the axial weight at the full load and the axial weight at the tolerance, and the difference between the pressure measured value at the full load and the pressure measured value at the full load of the vehicle. Vehicle load measurement device. Claim 29 was abandoned upon payment of a set-up fee. 28. The method of claim 27, wherein the friction release impact energy is Maximum dynamic pressure strain of the air spring of the vehicle when the load is applied while impacting the vehicle in a state where friction between the axle of the vehicle in which the sensor unit is installed and the fixing pin connecting the axle to the vehicle is released And the difference between the minimum dynamic pressure strain and the time to the minimum dynamic strain is calculated by multiplying. Claim 30 was abandoned upon payment of a registration fee. The method of claim 29, wherein the pressure measuring unit And measuring the dynamic strain by generating pressure measurements at time intervals of 20 to 200 times per second. Claim 31 was abandoned upon payment of a registration fee. 28. The method of claim 27, wherein the impact energy at the time of loading Maximum dynamic pressure strain of the air spring of the vehicle when the load is applied while impacting the vehicle in a state where friction between the axle of the vehicle in which the sensor unit is installed and the fixing pin connecting the axle to the vehicle is present And the difference between the minimum dynamic pressure strain and the time from the time of applying the load to the minimum dynamic strain is calculated. Claim 32 was abandoned upon payment of a registration fee. The method of claim 31, wherein the pressure measuring unit

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