JP3129176B2 - Method and apparatus for instructing calibration of vehicle load measuring sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the weight of a vehicle and / or the weight of the vehicle.
Also, the present invention relates to a method for instructing calibration of a load detection sensor in a device for measuring the weight of a load mounted on a vehicle, and a device therefor.

[0002]

In a vehicle that carries a load such as a truck, a magnetostrictive sensing element, a strain gauge, or the like is mounted on a member that receives a load due to the weight of the load in order to measure the load and / or the vehicle's own weight. Sensor is installed to detect the load.

FIG. 3 is a cross-sectional view taken along a center line of a trunnion shaft near a mounting portion of a vehicle load detecting sensor in a rear-wheel biaxial track.

In FIG. 3, a horizontal shaft portion 3a of a trunnion shaft 3 is supported at the lower portion of a trunnion bracket 2 which is attached by being expanded in an eight-shape from the lower surface of a carrier frame 1, and the bracket 2 At the end of the horizontal shaft portion 3a of the trunnion shaft projecting more in the vehicle width direction, a center portion of a leaf spring 11 is mounted via a spring seat 4 and a U-shaped fixture 15.

In the horizontal shaft portion 3a on both sides of the trunnion shaft 3, a hole 6 having a small diameter is formed from the shaft end 3b along the axis thereof. Magnetostrictive sensing element for detection, sensor 7 such as strain gauge
Are fitted and mounted. Reference numeral 53 denotes an electric harness for transmitting a detection signal from the sensor 7, which is led out of the vehicle from the shaft end of the horizontal shaft portion 3 a after being inserted through the hole 6.
It is connected to a load measuring circuit including a calibration means (not shown).

As the load detecting sensor 7, a magnetostrictive sensing element or a strain gauge is used. In the state where a constant voltage is applied to any of these sensing elements, as shown in FIG. ) Is applied to the sensor, and a portion where the signal output (voltage output) caused by the magnetostriction change or the strain change changes substantially linearly proportionally, in other words, a portion where the external force and the signal output change linearly proportionally, is taken out of the sensor. It is the detection part.

However, when such a sensing element is incorporated in the above-described vehicle load measuring device, the empty vehicle weight is displayed as "0" (home position display), for example, when a load is measured. The vehicle weight is applied to the sensing element, so that the sensing element deteriorates due to fatigue due to long-term use. In other words, even when the same load is applied, the output voltage is reduced due to the fatigue and the like. May change and the “0” point position may shift. For this reason, in the apparatus, it is necessary to periodically correct the shift amount and perform a return operation to the “0” point position.

FIG. 4 is a flow chart showing an example of a conventional procedure for returning to the "0" point position. In FIG. 4, first, when the vehicle load is empty, that is, when the vehicle has no load and has only the vehicle's own weight (S1),
It is determined whether or not the load amount display of the load display device (not shown) is “0”, that is, whether or not the load amount display is not deviated from “0”.
(S2)

If the display is not "0" but is shifted, the display is reset to "0" by a reset switch (not shown). (S3) If there is no deviation, the reset is not performed. After confirming the "0" point, the load is measured.

However, the return operation merely returns the display unit to the "0" point position, and does not repair the deterioration of the sensing element itself but corresponds to the "0" point shown in FIG. It only shifts the output voltage position to the right or left, so
The “0” point position may be out of the detection accuracy allowable range “A ₁ -A ₂ ” of the sensor characteristic shown in FIG. 5A, and accurate detection may not be possible.

Therefore, in order to continuously perform high-precision detection, the sensing must be performed before the "0" point position deviates from the detection accuracy allowable range "A ₁ -A ₂ " of the sensor characteristic shown in FIG. Calibration of element と Calibration is a function formula of (output voltage / load display) (eg, Y = aΧ +
If b) is changed as shown in FIG. 5 (B), or if the change of the function is not enough, the replacement of the sensor element is also included. Although it is necessary to perform｝, the change with time of the element deterioration has a variation for each element, and in the case of a vehicle, it greatly differs depending on a load load and a vibration state at the time of traveling, so that the calibration cycle period cannot be set uniformly. . For this reason, it is necessary to set the calibration cycle period in anticipation of a considerable safety factor, but this is not practical because the frequency of the calibration cycle is unnecessarily increased, and the maintenance cost is increased.

The present invention has solved the above-mentioned problems,
When the “0” point position deviates from the range of the detection accuracy tolerance “A _{1 to} A ₂ ” of the sensor characteristic shown in FIG. 5A, the sensor replacement time can be detected promptly and automatically, and the sensor output It is an object of the present invention to improve the operation rate of a vehicle while maintaining the display at a high accuracy at all times and without unnecessarily increasing the frequency of the calibration cycle, thereby maintaining the load amount of the load at an appropriate amount.

[0013]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and detects one or a plurality of load sensors such as a magnetostrictive sensing element and a strain gauge at appropriate positions on a vehicle component to detect a load on the vehicle. In a vehicle load measuring device for measuring the vehicle's own weight, loaded weight, etc., a new
The state of empty cargo upon delivery of the vehicle or each time calibration of the sensor is completed
Storing the initial output data (alpha) of the sensor in the reference load time corresponding to the vehicle weight in advance, the repetition of
In order to return the display to the home position position when the display on the display unit deviates from a reference load display position (generally, a "0" display position, hereinafter referred to as a home position position) at the time of the reference load by the vehicle load measurement. The output data (x) of the sensor when the reset means is operated is detected, and the difference (E = x-α) between the two output data (α) and (x) is calculated. E) is compared with the calibration allowable range (b) of the load sensor, and when the deviation (E) is smaller than the calibration allowable range (b), the reset operation is permitted, and the deviation (E) is within the range (B). b) displaying the execution of calibration of the sensor without permitting the reset operation when it is larger.

[0014] The invention according to claim 2 relates to an apparatus for smoothly performing such a calibration instructing method, wherein an empty cargo is loaded when a new vehicle is delivered to the vehicle or every time calibration of a sensor is completed.
And means for storing the initial output data of the sensor in the reference load time corresponding to the vehicle weight in the state of (alpha) (initial data storage unit 23), the display of the display unit at the reference load, the repetition of the vehicle loading Reset means (reset switch 21) for returning the display to the home position when the load is deviated from the reference load display position (home position) by the load measurement, and the sensor 7 when the reset means is operated. Means (deviation calculator 24) for detecting output data (x) and calculating a deviation (E = x-α) between the two output data (α) and (x);
The deviation (E) is compared with the calibration allowable range (b), and when the deviation (E) is smaller than the calibration allowable range (b), the reset operation is allowed. b) A calibration necessity judging means (judgment unit 25) for displaying the execution of calibration of the sensor 7 without permitting the reset operation when the reset operation is larger.

For example, when displaying the load capacity, when the reference load for which the display on the display section is "0" (home position position) is the empty load amount of the vehicle, in this state, the sensor 7 when there is no load. Is stored in advance in the initial data storage means. Here, the initial output data means the initial stage of each calibration cycle, and does not mean only the initial initial output data (α) of the new vehicle.

In the device, the vehicle weight is always applied to the sensing element because the vehicle weight exists even when the apparatus is empty, and the sensing element is applied to the sensing element by vibration or the like during traveling. Deterioration such as fatigue occurs, so the output voltage changes due to the fatigue and the like,
The “0” point position may shift.

For this reason, every time the shift occurs, reset means such as a reset switch is operated to correct the shift amount and perform a return operation to the “0” point position. Is an unloaded state, in other words, the output voltage level (output data) changes to the initial output data (α) despite the same load applied to the sensing element when the initial output data (α) is detected. ) Is different.

Accordingly, the output (x) of the sensor 7 is detected at each reset operation, and the deviation calculation unit calculates the deviation E between x and α, that is, the deviation E = x−α of the sensor 7. And
The calibration necessity determining unit 25 compares the deviation E with an allowable value of the deviation requiring calibration of the sensor 7, that is, an allowable range (b).
When E ≧ b, it is determined that accurate measurement cannot be performed even if the reset operation has already been performed, and a display signal to calibrate the sensor display without resetting is sent to the display device 22.

As a result, the driver recognizes whether or not the calibration of the sensor 7 is necessary, and the driver is not reset.
A measurement device that needs to be calibrated is not used by mistake. When E <b, the reset operation may be performed as it is.

As a result, the driver can reset the switch 2
By simply operating the resetting means such as 1 and looking at the display on the display device 22, the necessity of calibration of each sensor 7 can be accurately recognized. That is, unlike the conventional method, the frequency of the calibration cycle is not unnecessarily increased, thereby not only improving the operation rate of the vehicle while maintaining the load amount of the load at an appropriate amount, but also accurately and quickly setting the timing of the sensor calibration. Erroneous display of the sensor 7 and a decrease in the operating rate of the vehicle due to unnecessary frequency calibration work in anticipation of the safety factor can be prevented.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. It should be noted that the constituent circuits, shapes, quantities, and the like described in the following embodiments are not intended to limit the scope of the present invention but are merely illustrative examples unless otherwise specified. FIG. 1 shows a control device 10 in which only a calibration indicating device portion according to an embodiment of the present invention is extracted.
In the block diagram of FIG. 0, for example, a sensing element 7 is disposed on each of left and right shaft portions of a rear wheel side trunnion shaft and a front wheel side shackle pin portion, and a signal (output) of the sensing element 7 is provided. Voltage) is A / D converted and input to a load measuring device (not shown) in the control device 100,
The predetermined vehicle load or load load is displayed on the display device 22. Such a technique is known and is irrelevant to the present invention, so that the description thereof is omitted.

The calibration instruction device portion of the control device 100 stores each sensor initial output data (initial output data) for each calibration cycle based on an instruction from the CPU 20 comprising the deviation calculating section 24 and the calibration necessity determining section 25 and the like. α ₁ α ₂・ ・ ・ α ₄ )
And an allowable range storage unit 28 for storing allowable range data (b) for each sensor 7. Each of the storage units 23 and 28 is configured by a rewritable RAM. ing.

The reset switch 21 is a switch 21 for returning to the "0" point when the display on the display device 22 is shifted from the "0" position when there is no load.
Is input to the deviation calculator 24 of the CPU 20. The deviation calculator 24 fetches the output data x ₁ , x ₂ ... X _{4 of} each sensor 7 and the initial output data (α ₁ α ₂ ... Α ₄ ) when the reset signal is input. , Deviation (output display deviation) E ₁ = x ₁ −α ₁ , E ₂ = x ₂ −α ₂ ... E ₄
= A x ₄ -α ₄ respectively calculated.

The calibration necessity judging section 25 compares the deviations E ₁ ... With the allowable range (b). If E ≧ b, accurate measurement cannot be performed even if the reset operation has already been performed. Judgment is made, and a calibration signal for calibrating the sensor display without resetting is sent to the display device 22 via the output device 26. When E <b, a reset signal is sent to the display device 22 via the output device 26.

The display device 22 incorporates a portion for digitally displaying the load, a reset switch 21, a calibration display lamp, and the like (all not shown).

FIG. 2 is a flowchart showing a calibration procedure of the calibration instruction device. The calibration procedure will be described with reference to FIG.

In FIG. 2, at the time of delivery of a new vehicle or every time calibration of the sensor 7 is completed (S1), output data α ₁ α ₂ ... Α ₄ of the respective sensors 7 corresponding to the vehicle weight in an unloaded state. The data is input to the empty cargo data storage unit 23 and stored therein. (S
2) Then, the normal loading load measurement is performed. However, the position of the “0” point of the display device 22 may be shifted due to the repeated load measurement. For this reason, each time the displacement occurs, the reset switch 21 is turned ON when the vehicle is in an empty state.
Then, a return operation to the “0” point position is performed. (S3) output data x ₁ of each sensor 7 receives the reset signal at the deviation computing unit, x ₂ ··· x ₄ and the initial output data (α ₁ α ₂ ··
· Α ₄ ) and (S4), deviation (output display deviation) E
₁ = x ₁ −α ₁ , E ₂ = x ₂ −α ₂ ... E ₄ = x ₄ −α ₄ are calculated. (S5)

Next, in the calibration necessity judging section 25, the deviation E _{1 is} calculated.
.. And the allowable range (b). When E ≧ b, it is determined that accurate measurement cannot be performed even if the reset operation has already been performed. The signal is sent to the display device 22 via the output device 26.

When E <b, a reset signal is sent to the display device 22 via the output device 26 to perform a reset operation.

Accordingly, when the output of the sensor 7 is deviated and calibration is required, that is, when it is time to calibrate the sensor 7, this is automatically displayed on the display device 22 by the above procedure. Thus, the driver can be made aware of this, and the calibration time can be accurately detected.

[0031]

As described above, according to the present invention, the necessity of calibration of each sensor can be detected only by operating the reset means, and the timing of sensor calibration can be accurately recognized. . This prevents a decrease in the operation rate of the vehicle due to the above-described calibration, and also allows the sensor to be accurately calibrated at a required time, thereby preventing an excessively large or small amount of load due to an erroneous display of the sensor. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram of a calibration instruction device for a sensor for measuring a vehicle load of a large vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart of a calibration operation of the sensor.

FIG. 3 is a sectional view showing the vicinity of a sensor mounting portion of a trunnion shaft of a rear-wheel two-shaft heavy vehicle.

FIG. 4 is a flowchart showing a calibration procedure of a conventional vehicle measurement sensor.

FIG. 5 is a diagram illustrating an example of output characteristics of a vehicle load measuring sensor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 carrier frame 2 trunnion bracket 3 trunnion shaft 7 sensor (sensing element) 21 reset switch 22 display device 23 empty cargo data storage unit 24 deviation calculation unit 25 calibration necessity determination unit 28 allowable range storage unit 100 controller

Continuation of the front page (56) References JP-A-1-172711 (JP, A) JP-A-57-151828 (JP, A) JP-A-56-67720 (JP, A) JP-A-59-54821 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01G 19/12 G01G 23/01 G01G 23/36-23/375

Claims (2)

(57) [Claims] At least one load sensor such as a magnetostrictive sensing element or a strain gauge is attached to an appropriate position of a component of a vehicle to detect a load on the vehicle and to measure a weight of the vehicle, a weight of the vehicle, and the like. In the load measuring device, when the new vehicle is delivered or when calibration of the sensor is completed,
The initial output data (α) of the sensor at the time of the reference load corresponding to the vehicle weight in the unloaded state is stored , and the display on the display unit is displayed at the time of the reference load by the repeated measurement of the vehicle load. , Reference load display position (generally “0”
The display data (x) when the reset means for returning the display to the home position is operated when the display deviates from the display position (hereinafter referred to as the home position) is detected, and the two outputs are output. A deviation (E = x−α) between the data (α) and (x) is calculated, and the deviation (E) is compared with a calibration allowable range (b) of the load sensor. When the range (b) is smaller, the reset operation is allowed. When the deviation (E) is larger than the range (b), the calibration operation of the sensor is displayed without allowing the reset operation. Method for instructing calibration of a vehicle load measurement sensor. 2. A load measuring device for a vehicle, wherein a load sensor such as a magnetostrictive sensing element or a strain gauge is attached to a constituent member of the vehicle to detect a load on the vehicle and measure a weight of the vehicle, a loaded weight, and the like. When a new car is delivered or when sensor calibration is completed
Time, means for storing the initial output data of the sensor in the reference load time corresponding to the vehicle weight in the state of unloaded (alpha), the display of the display unit at the reference load, repeated vehicles product of
Reset means for returning the display to the home position when the load is deviated from the reference load display position (home position) by the load measurement; and output data (x) of the sensor when the reset means is operated. Means for calculating a deviation (E = x−α) between the two output data (α) and (x), and comparing the deviation (E) with the calibration allowable range (b). When the deviation (E) is smaller than the calibration allowable range (b), the reset operation is permitted. When the deviation (E) is larger than the range (b), the reset operation is not permitted. A calibration instructing device for a vehicle load measuring sensor, comprising: a calibration necessity determining unit for displaying execution of calibration.