JP2000111393A - Sensor-output correction device, load-offset-degree calculation device and loading-weight-value calculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor-output correction device by which the output of a weight sensor can be corrected with good accuracy on the basis of a nonlinear characteristic which contains the hysteresis or the like of the weight sensor as well as to provide a load-offset-degree calculation device and a loading-weight-value calculation device in which a load offset degree and a loading weight value are calculated on the basis of the output of every weight sensor after the load offset degree and the loading weight value are corrected by a sensor-output correction device. SOLUTION: A sensor-output correction device is provided with a weight sensor which is attached to a vehicle. Then, a correction-function holding means 35A by which a nonlinear characteristic containing the hysteresis of the weight sensor is approximated and which holds output-characteristic hysteresis correction functions to be divided into a plurality of linear characteristics to be used as a hysteresis loop is provided. In addition, an output-characteristic correction means 33A which corrects the output of the weight sensor by the output-characteristic correction functions selected from those held by the hysteresis correction-function holding means 35A on the basis of an increase or a decrease in the output of the weight sensor is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor output correction device provided with a weight sensor attached to a vehicle such as a truck, for correcting a signal output from the weight sensor.
The present invention relates to a loaded weight calculation device that calculates a loaded weight applied to a vehicle based on an output of a weight sensor corrected by the sensor output correction device, and a load deviation calculation device that calculates a deviation of a load in a vehicle width direction.

[0002]

2. Description of the Related Art For example, in the case of Japan, the measurement of the load weight of a vehicle mainly targets a large vehicle such as a truck.
For example, it is performed for the purpose of preventing traffic accidents such as rollover due to overloading and promotion of vehicle deterioration.

Conventionally, the measurement of the loaded weight of a vehicle is performed by mounting the vehicle to be measured on a platform scale. However, since the facility is large and requires a large installation space, the number of platform scales that can be installed is limited. In addition to being unable to measure the number of vehicles, installation costs have increased. Therefore, in recent years, a loading weight calculation device that is mounted on a vehicle itself and calculates a loading weight has been provided.

[0004] In a conventional loading weight calculation device mounted on a vehicle, for example, front, rear, left and right portions of a loading frame, a front,
Attach a sensing element for weight measurement such as a strain gauge sensor to an arc-shaped leaf spring interposed between the left and right ends of both rear axles (axle),
The load weight is calculated based on the sum of the outputs of the sensing elements in proportion to the load applied to the front, rear, left and right sensing elements.

[0005]

The sensing element such as the sensor in the prior art generally has a characteristic change when the load applied to the sensor increases and a characteristic change when the load decreases. Includes hysteresis where the output increases when the increase increases compared to when it decreases.
It has non-linear characteristics.

Therefore, when loading or unloading, for example, if the bias of the load is simply calculated from the output of each sensing element, the above-described influence of the hysteresis remains in the determined bias or the weight of the load. Therefore, for example, while the load applied to the vehicle is decreasing, the output of the sensing element becomes a value corresponding to a negative load value, and if the output value is used as a basis, an accurate bias or a weight to be loaded is calculated. You will not be able to do it.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to accurately correct the output of a weight sensor based on the non-linear characteristics including hysteresis of the weight sensor. An object of the present invention is to provide a sensor output correction device capable of performing the above.

A second object of the present invention is to accurately calculate the deviation in the vehicle width direction of the load applied to the vehicle based on the output of each weight sensor corrected by the sensor output correction device. The present invention is to provide a load deviation calculating device capable of performing the following.

Further, a third object of the present invention is to provide a load weight calculating device capable of calculating the load weight of a vehicle with high accuracy based on the output of each weight sensor corrected by the sensor output correcting device. It is in.

[0010]

According to a first aspect of the present invention, there is provided a sensor output correcting apparatus for correcting a signal output from a weight sensor mounted on a vehicle. A device, which approximates the non-linear characteristic including the hysteresis of the weight sensor, and a hysteresis correction function holding means for holding an output characteristic hysteresis correction function for dividing the hysteresis loop into a plurality of linear characteristics, Output characteristic correcting means for correcting the output of the weight sensor based on the output characteristic hysteresis correction function selected from those stored in the hiss correction function storing means based on an increase or decrease in the output of the weight sensor. It is characterized by:

In the above arrangement, the output characteristic correcting means changes the output of the weight sensor based on the increase or decrease of the output of the weight sensor.
By correcting with the output characteristic hysteresis correction function selected from the output characteristic hysteresis correction function held in the hiss correction function holding means, the output of the weight sensor after the correction is increased when the load of the vehicle increases and when the load of the vehicle decreases. The accuracy is higher than the output of the weight sensor which originally exhibits nonlinear characteristics including hysteresis. Accordingly, it is possible to provide a sensor output correction device capable of accurately correcting the output of the weight sensor based on the non-linear characteristics including the hysteresis of the weight sensor.

According to a second aspect of the present invention, there is provided a sensor output correcting apparatus according to the first aspect,
The hysteresis correction function holding means stores an output characteristic hysteresis function in which the hysteresis loop forms a parallelogram.

In the above configuration, the hysteresis correction function holding means in the sensor output correction device according to the first aspect holds the output characteristic hysteresis correction function in which the hysteresis loop forms a parallelogram. When the load of the vehicle increases and decreases, the output of the weight sensor after the correction is more accurate than the output of the weight sensor that originally exhibits nonlinear characteristics including hysteresis. Further, the output characteristic hiss correction function held by the hiss correction function holding means can be suppressed as small as possible.

According to a third aspect of the present invention, there is provided a load deviation calculating apparatus including the sensor output correcting apparatus according to the first or second aspect, wherein the weight characteristic of the weight sensor after being corrected by the output characteristic correcting means. The method is characterized in that a bias in the vehicle width direction of the load applied to the vehicle is calculated based on the output.

[0015] In the above configuration, the load deviation calculating device includes:
Since the sensor output correcting device according to claim 1 or 2 is provided, the output of the weight sensor after being corrected by the output characteristic correcting means of the sensor output correcting device is naturally of high accuracy. Since the deviation of the load applied to the vehicle in the vehicle width direction is calculated based on the corrected output of the sensor, an accurate load deviation calculating device is obtained.

According to a fourth aspect of the present invention, there is provided a loading weight calculating apparatus including the sensor output correcting apparatus according to the first or second aspect, wherein the output of the weight sensor after being corrected by the output characteristic correcting means. Based on the above, the load weight applied to the vehicle is calculated.

[0017] In the above configuration, the loaded weight calculating device includes:
Since the sensor output correcting device according to claim 1 or 2 is provided, the output of each weight sensor after being corrected by the output characteristic correcting means of the sensor output correcting device is of high accuracy as a matter of course. Since the load weight applied to the vehicle is calculated based on the output of the sensor after the correction, an accurate load weight calculating device can be obtained.

[0018]

An embodiment of the present invention will be described below with reference to the drawings.

First, a schematic configuration of a sensor output correction device according to the present invention will be described with reference to a basic configuration diagram of FIG.

A sensor output correcting apparatus according to the present invention is a sensor output correcting apparatus for correcting a signal output from a weight sensor mounted on a vehicle, wherein the sensor output correcting apparatus approximates a nonlinear characteristic including hysteresis of the weight sensor. Hysteresis correction function holding means 3 for holding an output characteristic hysteresis function for dividing into a plurality of linearity characteristics forming a hysteresis loop
5A and an output characteristic correcting means for correcting the output of the weight sensor by the output characteristic hysteresis correction function selected from among those stored in the hiss correction function storing means 35A based on the increase and decrease of the output of the weight sensor. 33A.

According to the sensor output correction device having such a configuration, the output characteristic correction means 33A outputs the output of the weight sensor based on the increase or decrease of the output of the weight sensor to the output characteristic hysteresis held in the hiss correction function holding means 35A. The output characteristics of the weight sensor, which is corrected by the output characteristic hysteresis correction function selected from the correction functions, when the load of the vehicle increases and decreases, originally exhibits a non-linear characteristic including hysteresis. Is more accurate than the output of

Further, the hysteresis correction function holding means 35A of the sensor output correction device of the present invention holds an output characteristic hysteresis correction function in which the hysteresis loop forms a parallelogram. As described above, when the load of the vehicle increases and decreases, the output of the weight sensor after the correction is higher in accuracy than the output of the weight sensor that originally exhibits nonlinear characteristics including hysteresis. Further, the output characteristic hiss correction function held by the hiss correction function holding means 35A can be suppressed as small as possible.

The specific configuration of the sensor output correcting device according to the present invention, which has been schematically described above, will be described in detail in the load deviation calculating device of the present invention described with reference to FIGS. To

The load deviation calculating device approximates the non-linear characteristic including the hysteresis of the weight sensor 21 and divides it into a plurality of linear characteristics as a hysteresis loop as shown in the basic configuration diagram of FIG. Correction function holding means 35A for holding an output characteristic hiss correction function for output, and the output characteristic hiss selected from those held in the hiss correction function holding means 35A based on an increase or decrease in the output of the weight sensor 21. Output characteristic correction means 33A for correcting the output of the weight sensor 21 by a correction function, based on the output of the weight sensor 21 corrected by the output characteristic correction means 33A of the sensor output correction device. In addition, the degree of deviation of the load applied to the vehicle 1 in the vehicle width direction is calculated.

The load deviation calculating device further includes a deviation display means 40 for displaying the deviation of the load applied to the vehicle 1 in the vehicle width direction. This is because not only the calculated deviation displayed on the deviation display means 40 is taken into account when calculating the loaded weight of the vehicle 1, but also the inclination of the load applied to the vehicle 1 by the displayed deviation. This makes it possible to recognize the state more accurately than judging by looking at the cargo.

Further, in the load deviation calculating device, the weight sensors 21 are provided at both end portions of each axle 9 of the vehicle 1 in the vehicle width direction, and are corrected by the output characteristic correcting means 33A. Later each of the weight sensors 2
1, the axle deviation values δ1 to δ1 indicating the direction and magnitude of the deviation in the vehicle width direction of the load applied to each of the axles 9
axle deviation value calculating means 33B for calculating δ3 for each axle 9; and weighting coefficients Q1 to Q unique to each axle 9 according to the arrangement of each axle 9 in the front-rear direction of the vehicle 1.
3 and a weighting coefficient holding means 35B for storing the axle deviation values δ1 to δ3 for each axle 9 calculated by the axle deviation value calculating means 33B.
Weighting coefficient Q1 corresponding to each axle 9 held in
To Q3.

The deviation in the vehicle width direction of the load applied to the vehicle 1 is determined by the axle deviation values δ1 × Q1 to δ for each axle 9 after weighting by the weighting factors Q1 to Q3.
The vehicle deviation value δ is calculated by adding 3 × Q3, and the deviation display means 40 has a vehicle deviation value display section 40d for displaying the vehicle deviation value δ.

As a result, the output M1 to M6 of each weight sensor 21 after the influence of the non-linear characteristic including hysteresis and the like is eliminated by the correction using the output characteristic hysteresis correction function.
The axle deviation values δ1 to δ3 for each axle 9 of the vehicle on which the respective weight sensors 21 are arranged are calculated by the axle deviation value calculating means 33B.
, The direction and magnitude of the bias of the load for each axle 9 can be accurately calculated.

Each axle 9 in the front-rear direction of the vehicle 1
Weighting coefficient holding means 35 determined according to the arrangement of
The axle deviation values δ1 to δ3 of the corresponding axles 9 are weighted by the weighting means 33C according to the weighting factors Q1 to Q3 unique to each axle 9 held by B, and the axle deviation values δ1 for each axle 9 after weighting. By calculating a vehicle deviation value δ indicating the deviation of the load applied to the vehicle 1 in the vehicle width direction on the basis of ~ δ3, the distribution of the load applied to each axle 9 in the front-rear direction of the vehicle 1 was further considered. A highly accurate vehicle deviation value δ is calculated.

Therefore, by displaying the vehicle deviation value δ on the vehicle deviation value display section 40d of the deviation display means 40, it is possible to determine in which direction of the vehicle width the load is generally deviated in the vehicle width direction.
Recognition can be made easily and easily under a certain standard.

Further, since the deviation display means 40 has the deviation direction display sections 40a to 40c for displaying the direction of the deviation in the vehicle width direction of the calculated load applied to the vehicle 1, the deviation is displayed. The direction of the degree of deviation displayed on the direction display units 40a to 40c makes it possible to visually indicate in which direction the load is generally deviated in the vehicle width so that it can be visually recognized and easily recognized. Becomes

FIGS. 3A and 3B are explanatory views showing a vehicle location where a sensing element of the load deviation calculating device according to a preferred embodiment of the present invention is provided, wherein FIG. 3A is a side view, and FIG. FIG. 4 is an exploded perspective view of a structure for supporting the leaf spring of FIG. 3 on a carrier frame of a vehicle, and FIG. 5 is a sectional view showing a sensing element provided in the shackle pin of FIG.

In FIGS. 3A and 3B, reference numeral 1
Denotes a vehicle, and the vehicle 1 has wheels 3, a carrier frame 5, and a carrier 7.

The above-mentioned wheels 3 are provided on the front, middle, rear and left and right six wheels. At both ends.

The carrier 7 is supported on the carrier frame 5. The left and right front and rear spaces of the carrier frame 5 are separated by leaf springs 11 from the front, middle and rear axles 9. It is supported by the left and right ends, respectively.

As shown in FIG. 4, the leaf spring 11 is formed in a substantially arcuate shape convex on the ground side by laminating strip-shaped spring plates, and both ends in the longitudinal direction thereof are connected to the carrier frame 5. Are supported by two brackets 13 attached at locations spaced apart in front and behind. In particular, the rear end of the vehicle 1 with the leaf spring 11 is swingably supported by the bracket 13 by a shackle 15 provided between the bracket 13 and the leaf spring 11.

In the figure, reference numeral 17 denotes a bracket 13
5 shows a shackle pin that swingably connects the shackle 15 and the shackle 15.

In the vehicle 1 having such a configuration, the load deviation calculating device includes the sensing element 21 and the weighing scale 31 (FIG. 7) to which the sensing element 21 is connected, and calculates the deviation applied to the vehicle 1. The sensing element 21 (corresponding to a weight sensor) used for calculating the weight of the vehicle 1 is also used. The sensing element 21 is disposed in each of the shackle pins 17 for connecting the shackle 15 and the six brackets 13 on the left, right, front and rear.

In the present embodiment, each of the sensing elements 21 is formed of a magnetostrictive gauge sensor (not limited to this). As shown in FIG. 5, the sensing element 21 extends from one end of the shackle pin 17 in the axial direction. It is attached to the web 19a of the holding member 19 housed in the bore 17a. When the sensing element 21 is of a magnetostrictive type, it is fitted into a receiving hole (not shown) formed in the web 19a.

As shown in the block diagram of FIG. 6, each of the six front, middle, rear, left and right sensing elements 21 disposed in the six front, middle, rear, left and right shackle pins 17 is provided with a sensor 23 and a voltage sensor. / Frequency converter (hereinafter abbreviated as V / F converter) 25.

The sensor 23 includes a magnetostrictive element 23a and a transformer 23b having the magnetostrictive element 23a as a magnetic path. The V / F converter 25 includes an oscillator 25a connected to a primary winding of the transformer 23b, and a detector 25b connected to a secondary winding of the transformer 23b.
A V / F conversion circuit 25c connected to the detector 25b.

The sensing element 21 includes an oscillator 25a
A current is caused to flow through the primary winding of the transformer 23b by the output signal from the transformer 23b, thereby inducing an AC voltage in the secondary winding of the transformer 23b. The AC voltage is converted by the detector 25b into a DC voltage. The / F conversion circuit 25c is configured to convert the DC voltage into a pulse signal having a frequency proportional to the voltage value and output the pulse signal to the outside.

A high-resistance resistor 25d is connected between the oscillator 25a and the primary winding of the transformer 23b, and is induced in the primary winding of the transformer 23b by the resistor 25d. The voltage value of the AC voltage
There is no change even if the output signal of a slightly fluctuates. The conversion of the AC voltage induced in the secondary winding of the transformer 23b into the DC voltage by the detector 25b is performed by multiplying the AC voltage by the voltage generated at both ends of the resistor 25d. , The noise component contained in the AC voltage is reduced.

In the sensing element 21, the magnetic permeability of the magnetostrictive element 23a changes due to the load applied to the magnetostrictive element 23a, whereby the output signal from the oscillator 25a is induced in the secondary winding of the transformer 23b. When the AC voltage changes, the frequency of the pulse signal output from the V / F conversion circuit 25c increases or decreases.

By the way, the outputs of the six front, middle, rear, left and right sensing elements 21 disposed in the four front, middle, rear, right and left shackle pins 17 are corrected and the corrected outputs of the sensing elements 21 are corrected. The calculation of the bias of the vehicle 1 based on
As shown in the front view of FIG. 7, the loading weight meter 3 included in the vehicle 1 and constituting the load deviation calculating device of the present invention.
The microcomputer 33 (hereinafter, abbreviated as “microcomputer”) provided in 1 (see FIG. 8) performs the processing at a stage prior to the calculation of the load weight.

On the front surface 31a of the weighing scale 31, a deviation display area 40 (corresponding to a deviation display means) for displaying the deviation of the vehicle 1 calculated by the microcomputer 33 is provided. , A load weight display section 37 for displaying the calculated load weight of the vehicle 1, an overload display lamp 41 for displaying that the load weight exceeds a predetermined maximum load weight, and an alarm buzzer for informing the overload state. 43, an offset adjustment value setting key 45, an overload weight value setting key 47,
3, a reset key 54, a set key 55, and the like.

The deviation display area 40 has three states of left deviation, uniform deviation and right deviation displaying the state of the deviation of the load, that is, the direction of deviation of the loaded weight in the vehicle width direction as viewed from the entire vehicle 1. Deflection display lamps 40a to 40c (corresponding to the deviation direction display section)
And a deviation value display section 40d composed of, for example, a 7-segment light emitting diode group for displaying a vehicle deviation value δ in which the magnitude of the deviation described later and the direction of the vehicle width direction are quantified.

As shown in the block diagram of FIG. 8, the microcomputer 33 includes a CPU (Central Processing Unit) 33a and a RAM (Random Access Memory).
33b and a ROM (Read-Only Memory) 33c.

The CPU 33a has a non-volatile memory (NVM) that does not lose stored data even when power supply is cut off.
35 (corresponding to the hiss correction function holding means 35A and the weighting coefficient holding means 35B), the offset adjustment value setting key 45, and the overload weight setting key 47 used for calculating the overload and judging the overload based on the result. , Numeric keypad 5
3, a reset key 54 and a set key 55 are directly connected to each other, and each of the sensing elements 21 is connected to a travel sensor 57 that generates a travel pulse in accordance with the travel of the vehicle 1 via an input interface 33d. Have been.

Further, the load weight display section 37, the CPU 33a via the output interface 33e.
Left-sided, equal, right-sided load display lamps 40a-40c
And a bias value display section 40d, an overload display lamp 41, and an alarm buzzer 43, respectively, for calculating the load weight and outputting the result of the overload determination based on the calculated value.

The RAM 33b has a data area for storing various data and a work area used for various processing operations. Of these, the work area includes the correction of the output of each sensing element 21 and the load weight. Calculation and
Various register areas, various flag areas, and the like are provided for use in overload determination based on the calculated value.

The ROM 33c stores a control program for causing the CPU 33a to perform various processing operations.

Each sensing element 2 is provided in the NVM 35.
Tables of the offset adjustment value, output characteristic hysteresis correction function, and error correction value for the output pulse signal of No. 1 and a weighting coefficient specific to each axle 9 used when obtaining the vehicle deviation value δ (unit =%) From Q1 to Q3 and the vehicle deviation value δ, a deviation determination value for determining which one of the three deviation display lamps 40a to 40c of left deviation, equality, and right deviation to turn on, and Weight conversion formulas and the like are stored in advance.

The adjustment values in the offset adjustment value table are used to eliminate variations in the frequency of the pulse signals output by the six sensing elements 21 in the tare state of the vehicle 1. It is set for each sensing element 21 by the setting process in the tare state.

The adjustment value of each sensing element 21 is a difference value (unit: Hz) between the frequency of the output pulse signal in the tare state of each sensing element 21 and the reference frequency 200 Hz of the pulse signal when the loading weight = 0 ton. The specific range of the adjustment value is between +170 Hz and -500 Hz.

Accordingly, the sensing element 21 whose offset value can be adjusted by the adjustment value has a frequency value of the output pulse signal in the range of 30 Hz to 700 Hz in the tare state.

The output characteristic hiss correction function of the output characteristic hiss correction function table indicates that when the load applied to each sensing element 21 is increased, it is smaller than when the load applied to each sensing element 21 decreases.
In order to divide the characteristic into a plurality of linearity characteristics as a hysteresis loop as shown in FIG. The output characteristic hiss correction function is set for each sensing element 21 before the sensing element 21 is disposed in the shackle pin 17.

In FIG. 9, the non-linearity characteristic is approximated and divided into four continuous linearity characteristics forming a parallelogram hysteresis loop, and when the load increases up to W1, the first output characteristic is reduced. The hiss correction function K11, the second output characteristic hiss correction function K12 when the load increases in the range from W1 to W2, and the third output characteristic hiss correction function K21, W3 to W4 when the load decreases in the range from W2 to W3. In the range of load reduction, the fourth output characteristic hysteresis correction function K2
The characteristic is corrected using each output characteristic hiss correction function of No. 2.

As can be seen from FIG. 9, the first output characteristic hiss correction function K11 and the third output characteristic hiss correction function K2
1. The second output characteristic hiss correction function K12 and the fourth output characteristic hiss correction function K22 have the same slope.

The present invention is not limited to a parallelogram hysteresis loop (it can be divided into finer linearity characteristics), but if such a loop is formed,
It is possible to minimize the area of the output characteristic hiss correction table.

The error correction value in the error correction value table is:
This is for correcting the variation between the sensing elements 21 in the characteristic relating to the correlation between the load applied to each sensing element 21 and the output pulse signal, and the error correction value is:
Prior to disposing the sensing elements 21 in the shackle pin 17, the setting is made for each sensing element 21.

Further, the error correction value of each sensing element 21 is set so that the slope of the line indicating the correlation between the load applied to the sensing element 21 and the output pulse signal matches the slope of the line indicating the reference characteristic. This is a correction coefficient by which the frequency of the pulse signal output from the element 21 is multiplied.

As described in the description of the output characteristic hysteresis correction function, the sensing element 21 has a non-linear characteristic including hysteresis, and has a certain characteristic expression depending on the frequency band of the output pulse signal. , The characteristic equation of the pulse signal changes to another characteristic equation. Therefore, in practice, a single error correction value is not set for each sensing element 21, but in the frequency domain between adjacent change points. A plurality of error correction values to be applied are set for one sensing element 21.

The weighting factor Q1 unique to each axle 9
Q3 are the magnitude of the deviation in the left and right direction of the load applied to each axle 9, which is obtained from the frequency of the output pulse signal of each sensing element 21 after the offset adjustment, the correction using the output characteristic hysteresis correction function, and the error correction. This is for weighting the axle deviation values δ1 to δ3 (unit =%), which indicate the direction, according to the ratio of load distribution to each axle 9, and is an empirical value determined by the type and structure of the vehicle 1. is there.

In the present embodiment, the weighting factor Q1 of the front axle 9 is 0.1 and the weighting factor Q of the middle axle 9 is Q1.
2 = 0.3, weighting coefficient Q3 of rear axle 9 = 0.6
Is set to

When the vehicle deviation value δ exceeds this value (range), the load is biased to the left when the vehicle deviation value δ exceeds this value (range).
When the value falls below, the load is biased to the right, and at this value (within the range), it is a reference value for determining that the load is uniformly applied in the left-right direction. In the present embodiment, the bias determination value is- 5 ≦ δ ≦ 5 is set.

In the weight conversion formula, the total frequency before gain correction obtained by summing the frequencies of the output pulse signals of the respective sensing elements 21 before gain correction is corrected by the corresponding correction value data Z1 to Z6 on the gain correction value table. Subtract 200 Hz, which is the reference frequency of the pulse signal when the load weight is 0 ton, from the total frequency after the gain correction, and add 0.01 ton, which is the unit conversion weight per 1 Hz, to the frequency corresponding to the load weight after the subtraction. Is an expression that is multiplied by

Therefore, for example, six sensing elements 21
When the total frequency after gain correction obtained from the frequency of the output pulse signal is 700 Hz, the loaded weight = 5 tons is calculated by the weight conversion formula, and when the total frequency is 1200 Hz, the loaded weight = 10 tons. In addition, the second decimal place of the calculated loading weight is rounded off.

Next, the processing performed by the CPU 33a in accordance with the control program stored in the ROM 33c will be described with reference to the flowcharts of FIGS.

Accessory (ACC) not shown for the vehicle
When the key is turned on for the first time, the weighing scale 31 is turned on and the microcomputer 33 is started to start the program. The CPU 33a performs initial setting according to the main routine shown in the flowchart of FIG. 10 (step S).
1).

In this initial setting, detailed description is omitted in this embodiment. The values stored in the various register areas of the RAM 33b used for correcting the outputs of the six sensing elements 21 and calculating the loaded weight of the vehicle 1 are reset to zero. Or setting the flags of various flag areas to “0”.

Subsequently, it is confirmed whether or not there is a setting mode request by operating the offset adjustment value setting key 45 or the overload weight setting key 47 (step S3). If there is no request (N in step S3), The process proceeds to step S7 described later, and if there is a request (Y in step S3), step S5
Proceed to the setting process.

In the setting process, the request is confirmed in step S3 as shown in the flowchart of FIG.
It is confirmed whether or not the operation is performed by operating the offset adjustment value setting key 45 (step S5a). If the operation is performed by operating the offset adjustment value setting key 45 (Y in step S5a), the vehicle 1 is set to the tare state. Here, the frequency of the pulse signal input from each sensing element 21 via the input interface 33d is determined (Step S
5b).

Next, the calculation for subtracting 200 Hz, which is the reference frequency when the loading weight is 0 ton, from the frequency of the output pulse signal of each sensing element 21 determined in step S5b to calculate the loading weight frequency is performed by the RAM.
Performed in the calculation area 33b (step S5c),
After writing the calculated frequency values obtained by inverting the + and-signs of the six frequencies into the NVM 35 as offset adjustment values of the respective sensing elements 21 (step S5d), FIG.
It returns to step S3 of the main routine of 0.

On the other hand, if the request confirmed in step S3 is not due to the operation of the offset adjustment value setting key 45 (N in step S5a), an overload weight value setting process is performed (step S5e).

In the overload weight setting process, although the detailed description is omitted, the input value by the ten keys 53 is canceled by operating the reset key 54, and is confirmed by operating the set key 55, and the input value is input. A process of writing the value into the NVM 35 as a weight value to be used as a criterion of overloading is performed.

When the overload weight value setting process is completed, FIG.
It returns to step S3 of the main routine of 0.

In step S7, in which there is no setting mode request in step S3 (N), it is confirmed in step S7 whether or not a travel pulse from the travel sensor 57 has been input. If it has been input (Y), the flow proceeds to step S3. Returning, if not input (N), the frequency of the pulse signal input from each sensing element 21 is determined (step S9), and then the frequency of the output pulse signal of each sensing element 21 determined in step S9 Are all within the range of 30 Hz to 700 Hz at which the offset can be adjusted by the offset adjustment value (step S11).

If the frequency of the output pulse signal of any one of the sensing elements 21 is out of the range of 30 Hz to 700 Hz (N in step S11), for example, the alphabet "E" is displayed on the bias value display section 40d. .Lo "(step S13), and the process returns to step S3.
Output pulse signals all have a frequency of 30 Hz to 700 Hz
If it is within the range (Y in step S11), the process proceeds to step S15.

In step S15, the frequency of the pulse signal input from each sensing element 21 determined in step S9 is offset-adjusted by the offset adjustment value of NVM 35 in the calculation area, and the frequency from each sensing element 21 after the offset adjustment is adjusted. In the calculation area, the pulse signal frequency is subjected to a characteristic correction process described later using the output characteristic hysteresis correction function of the NVM 35 (step S17), and the pulse signal frequency from each sensing element 21 after the offset adjustment and the characteristic correction process is calculated. In the area, the error is corrected by the error correction value of the NVM 35 (step S19).

In the characteristic correction processing in step S17, the processing shown in FIG.
As shown in the flowchart of FIG.
7a, output W of sensing element 21 after offset adjustment
It is checked whether or not i is Wi> 0. If Wi> 0 (Y in step S17a), it is checked in step S17b whether the load is increasing.

If the load has increased (Y in step S17b), it is checked in step S17c whether the load is within the correction range of the first output characteristic hiss correction function K11. If it is within the correction range of the first output characteristic hiss correction function K11 (Y in step S17c), step S17 is performed.
At 17d, the output is corrected by the first output characteristic hiss correction function K11, and the correction value is set as the output Mi of the sensing element 21. Conversely, if it is within the correction range of the second output characteristic hiss correction function K12 (N in step S17c), step S17
The output is corrected by the second output characteristic hiss correction function K12 at e, and the correction value is set as the output Mi of the sensing element 21.

On the other hand, if the load is reduced (N in step S17b), it is checked in step S17f whether the load is within the correction range of the third output characteristic hiss correction function K21. If it is within the correction range of the third output characteristic hiss correction function K21 (Y in step S17f), the output is corrected by the third output characteristic hiss correction function K21 in step S17g, and the correction value is output from the sensing element 21. Mi
And

When the value does not fall within the correction range of the third output characteristic hiss correction function K21 in step S17f (step S17).
In N) at 17f, it is confirmed whether or not it is within the correction range of the fourth output characteristic hiss correction function K22 (step S17).
h). Then, if it is within the correction range of the fourth output characteristic hiss correction function K22 (Y in step S17h), the output is corrected by the fourth output characteristic hiss correction function K22 in step S17i, and the correction value is output from the sensing element 21. Mi. In step S17h, the fourth output characteristic hiss correction function K
22 is not within the correction range (step S17h
, N), the output is corrected by the first output characteristic hiss correction function K11, and the correction value is output to the output Mi of the sensing element 21.
(Step S17j).

Thereafter, the flow advances to step S17k to rewrite the pulse signal frequency of the sensing element 21 used for the next judgment of the increase or decrease of the load with the previous one, and returns to step S19 of the main routine in FIG.

If the output Wi of the sensing element 21 after the offset adjustment is Wi ≦ 0 in step S17a (N in step S17a), the flow advances to step S17m to output the output Mi of the sensing element after the characteristic correction to Mi = The value is set to 0, and the process proceeds to step S17k.

Also, i is the position number of the sensing element 21, and the sensing element 21 on the left side of the front axle 9 is i =
1, right sensing element 21 is i = 2, middle axle 9
Is i = 3, the right sensing element 21 is i = 4, the left sensing element 21 of the rear axle 9 is i = 5, and the right sensing element 21 is i = 6.
It is.

Based on the outputs M1 to M6 of the respective sensing elements 21 after the characteristic correction processing in step S17, step S
19, the outputs M′1 to M′6 of each sensing element 21 after the error correction (M′i = 0 in the case of Mi = 0) and the unique axle 9 of the NVM 35 Based on the weighting coefficients Q1 to Q3, the axle deviation values δ1 to δ3 for each axle 9 are calculated (step S21).

First, the calculation of the axle deviation value δ1 of the front axle 9 is performed after the characteristic correction processing of the two sensing elements 21 arranged on the left and right of the front axle 9 and the outputs M′1 and M ′ after error correction. Δ1 = (M′1−M′2)}
This is performed by the equation (M′1 + M′2).

Similarly, the calculation of the axle deviation values δ2, δ3 of the middle axle 9 and the rear axle 9 was performed after the characteristic correction processing of the two sensing elements 21 disposed on the left and right of the middle axle 9, and the error was corrected. The output M'3, M'4 after the error correction after the characteristic correction processing of the two outputs M'3, M'4 and the two sensing elements 21 arranged on the left and right of the rear axle 9 are used. , Δ2 = (M'3-M '
4) The formula of ′ (M′3 + M′4) and δ3 = (M′5−
M′6) ÷ (M′5 + M′6). However, the denominator of each equation, that is, (M'1 + M '
2), (M'3 + M'4) and (M'5 + M'6)
Are respectively “0”, the corresponding axle deviation value δ
The values of 1 to δ3 are δ1 to δ3 = 0.

If the axle deviation values δ1 to δ3 for each axle 9 have been calculated in step S21, the respective axle deviation values δ1
Weighting coefficient Q1 unique to each axle 9 corresponding to.
To Q3, and axle deviation value δ for each axle 9
1 to δ3 are weighted, and the axle deviation values δ1 × Q1 to δ3 × Q3 for each axle 9 after the weighting are summed to calculate the vehicle deviation value δ (step S23).

Subsequently, the calculated vehicle deviation value δ is calculated according to the NVM
It is checked whether or not the value is within the range of the skewness determination value −5 ≦ δ ≦ 5 stored in 35 (step S25). If the value is not within the range (N in step S25), step S25 to be described later is performed.
If it is within the range (Y in step S25), the uniform load display lamp 40b is turned on and the other display lamps 40a and 40c are turned off (step S2).
7) The process proceeds to step S35 described below.

If the vehicle deviation value δ is not within the range of the deviation determination value −5 ≦ δ ≦ 5 in step S25, the process proceeds to step (N). In step S29, it is determined whether the vehicle deviation value δ is positive. If the value is positive (Y in step S29), the left eccentric load display lamp 40a is turned on and the other display lamps 40b and 40c are turned off (step S3).
1) The process proceeds to step S35, and if not positive (N in step S29), the right offset load display lamp 40c is turned on and the other display lamps 40a and 40b are turned off (step S33), and then the process proceeds to step S35. .

In step S35, the deviation value display section 40d
Is updated to the vehicle bias value δ calculated in step S23, and thereafter, the process returns to step S3.

As is clear from the above description, in the present embodiment, the output characteristic correcting means 33A of the sensor output correcting device described in the claims is executed by the characteristic correcting process in step S17 in the flowchart of FIG. It is configured. Incidentally, the axle deviation value calculating means 33B is constituted by step S21 in FIG.

Next, the operation (action) relating to the calculation of the vehicle bias value δ by the loading weight meter 31 of the present embodiment configured as described above will be described.

First, when the offset adjustment value setting key 45 is operated, a state of waiting for the input of the offset adjustment value is entered. Here, when a numerical value is input by operating the numeric keypad 53 and the set key 55, the value is set to the value of the sensing element 21. The offset adjustment value is written to the NVM 35.

Next, when the offset adjustment value setting key 45 is not operated and the running pulse from the running sensor 57 is not input, the signals are output from the sensing elements 21 at both ends of each axle 9. A pulse signal having a frequency corresponding to the load applied to both ends of each axle 9 is corrected by an offset adjustment value of the NVM 35 corresponding to the frequency. This eliminates variations in the output frequency among the sensing elements 21 in the tare state.

Subsequently, the output pulse signal of each sensing element 21 after the correction by the offset adjustment value is corrected by the output characteristic hysteresis correction function of the NVM 35 corresponding to the frequency. As a result, the output of each sensing element 21 changes from a non-linear characteristic to a linear characteristic, and the hysteresis that the frequency of the output pulse signal of the sensing element 21 increases when the load increases compared to when the load decreases. Is taken into account, and the accuracy is improved.

Further, the output pulse signal of each sensing element 21 corrected by the offset adjustment value and the output characteristic hysteresis correction function is corrected by the error correction value of the NVM 35 corresponding to the frequency. This eliminates variations in characteristics between the sensing elements 21 regarding the correlation between the load and the output pulse signal.

After the correction using the offset adjustment value, the output characteristic hysteresis correction function, and the error correction value, based on the output pulse signal of the sensing element 21 for each axle 9,
The axle deviation values δ1 to δ3 are calculated, and the vehicle deviation value δ, which is the load deviation of the entire vehicle 1, is calculated based on the axle deviation values δ1 to δ3 and the weighting factors Q1 to Q3 unique to each axle 9.

The calculated value of the vehicle deviation value δ is numerically displayed on the deviation value display section 40d, and the value of the vehicle deviation value δ is -5 ≦ δ ≦ 5 (equal), 5 <δ ( The corresponding one of the left-sided, equalized, and right-sided load indicating lamps 40a to 40c is turned on according to the range of leftward) or δ <−5 (rightward).

After that, for example, the frequencies of the output pulse signals of the respective sensing elements 21 are summed, and the sum frequency is used to correct the error between the unbalanced load and the uniform load. It is corrected by the gain correction value corresponding to δ, 200 Hz which is the reference frequency of the pulse signal when the loading weight is 0 ton is subtracted from the corrected total frequency, and the frequency corresponding to the loading weight after the subtraction is converted into a unit per 1 Hz. The load weight of the vehicle is calculated by multiplying the weight by 0.01 ton or the like, and the calculated value is displayed on the load weight display section 37 (constituting the load weight calculation device).

When the calculated load weight exceeds a predetermined overload weight value, the overload display lamp 41 is turned on or the alarm buzzer 43 is sounded to notify the overload state.

As described above, according to the load deviation calculating device of the present embodiment, the width of the vehicle 1 is determined based on the outputs of the sensing elements 21 disposed at both ends of the front, middle, and rear axles 9, respectively. Axle deviation values δ1 to δ3 indicating the deviation of the load for each axle 9 in the direction are calculated, and these axle deviation values δ1 to δ3 are further weighted by a weighting factor Q1 unique to each axle 9.
By calculating the vehicle deviation value δ, which is the deviation of the load for the entire vehicle 1,
The output of each sensing element 21 is configured to be corrected from a non-linear characteristic to a linear characteristic by an output characteristic hysteresis correction function.

Therefore, the hysteresis that the frequency of the output pulse signal of each sensing element 21 is higher when the load increases than when the load decreases is sufficiently considered, and the accuracy can be improved. it can. That is,
The accuracy of the axle deviation values δ1 to δ3 and the vehicle deviation value δ calculated based on the output of each sensing element 21 can be significantly improved. In addition, the accuracy can be remarkably improved in the case where the loaded weight calculating device is configured.

In addition, it goes without saying that the present invention can be variously modified without departing from the gist of the present invention. Further, the configurations of the load deviation calculating device and the loaded weight calculating device can be variously changed and implemented.

[0108]

As described above, according to the first aspect of the present invention, the output characteristic correcting means transfers the output of the weight sensor to the hiss correction function holding means based on the increase or decrease of the output of the weight sensor. By correcting with the output characteristic hysteresis correction function selected from the held output characteristic hysteresis correction functions,
When the load of the vehicle increases and decreases, the output of the weight sensor after the correction is more accurate than the output of the weight sensor that originally exhibits nonlinear characteristics including hysteresis. From this, it is possible to provide a sensor output correction device capable of accurately correcting the output of the weight sensor based on the non-linear characteristics including the hysteresis of the weight sensor.

According to the second aspect of the present invention, the hysteresis correction function holding means in the sensor output correction apparatus according to the first aspect holds an output characteristic hysteresis correction function in which a hysteresis loop forms a parallelogram. Therefore, as described above, when the load of the vehicle increases and decreases, the output of the weight sensor after the correction is more accurate than the output of the weight sensor that originally exhibits nonlinear characteristics including hysteresis. Become. Further, the output characteristic hiss correction function held by the hiss correction function holding means can be suppressed as small as possible.

According to the third aspect of the present invention, the load deviation calculating device includes the sensor output correcting device according to the first or second aspect. The output of the weight sensor after being corrected by the characteristic correction means is of high accuracy as a matter of course,
Since the deviation in the vehicle width direction of the load applied to the vehicle is calculated based on the output of the sensor after the correction, it is possible to provide an accurate load deviation calculating device.

According to the fourth aspect of the present invention, since the loaded weight calculating device includes the sensor output correcting device according to the first or second aspect, the output characteristic of the sensor output correcting device is improved. Naturally, the output of each weight sensor after being corrected by the correcting means has high accuracy, and the load weight applied to the vehicle is calculated based on the corrected output of the sensor. It is possible to provide a good load weight calculating device.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a sensor output correction device according to the present invention.

FIG. 2 is a basic configuration diagram of a load deviation calculating device according to the present invention.

FIG. 3A is a side view showing a vehicle location where a sensing element of the load deviation calculating device according to the present invention is disposed, and FIG.
FIG. 4 is a plan view showing a vehicle location where a sensing element of the load deviation calculating device according to the present invention is disposed.

FIG. 4 is an exploded perspective view of a structure for supporting the leaf spring of FIG. 3 on a carrier frame of a vehicle.

FIG. 5 is a cross-sectional view showing a sensing element provided in the shackle pin of FIG. 4;

FIG. 6 is a circuit diagram partially showing a configuration of a sensing element shown in FIG. 5;

FIG. 7 is a front view of a weighing scale constituting the load deviation calculating device according to the present invention.

8 is a block diagram showing a hardware configuration of the microcomputer shown in FIG.

FIG. 9 is an explanatory diagram of an output characteristic hysteresis correction function stored in the NVM shown in FIG. 7;

FIG. 10 is a flowchart showing a process performed by a CPU according to a control program stored in a ROM of the microcomputer shown in FIG. 7;

11 is a flowchart showing a subroutine of the setting process shown in FIG.

12 is a flowchart showing a subroutine of the characteristic correction processing shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle 9 Axle 21 Weight sensor 31 Loading scale 33 Microcomputer 33a CPU 33b RAM 33c ROM 33A Output characteristic correction means 33B Axle deviation value calculation means 33C Weighting means 35 NVM 35A His correction function holding means

Claims (4)

[Claims] 1. A sensor output correction device for correcting a signal output from a weight sensor attached to a vehicle, wherein the sensor output correction device approximates a nonlinear characteristic including a hysteresis of the weight sensor to form a hysteresis loop. A hiss correction function holding means for holding an output characteristic hiss correction function for dividing the linearity characteristic into a linear characteristic, and a hysteresis correction function holding means for selecting from among the hysteresis function holding means based on an increase or decrease in the output of the weight sensor. An output characteristic correction unit that corrects the output of the weight sensor using the output characteristic hiss correction function. 2. The sensor output correction apparatus according to claim 1, wherein said hysteresis correction function holding means holds an output characteristic hysteresis correction function in which said hysteresis loop forms a parallelogram. Correction device. 3. The sensor output correction device according to claim 1, wherein the output of each of the weight sensors corrected by the output characteristic correction means is used to calculate a load applied to the vehicle. A load deviation calculating device for calculating a deviation in a vehicle width direction. 4. A sensor output correction device according to claim 1 or 2, wherein a load weight applied to the vehicle is calculated based on an output of the weight sensor corrected by the output characteristic correction means. A load weight calculating device.