CN102252691A - Measuring method of automobile tyre correction coefficient - Google Patents

Abstract

The invention discloses a measuring method of an automobile tyre correction coefficient. The method performs high-precision range finding mainly by forming an ultrasonic ranging mode by using an auxiliary target which is composed of two ultrasonic receivers with different mounting heights and fixed distances; performs accurate measurement of a driving stroke by the auxiliary target which is composed of the two ultrasonic receivers; performs continuous rotational angle measurement by forming a dip measuring mode by using a triaxial tilt sensor which does not require installation on a rotation shaft; performs accurate dip measurement by verticality correction, and realizes the accurate measurement of the tyre correction coefficient. The invention increases the measurement accuracy, and has simpler operation. As a measuring method of an automobile tyre correction coefficient, the invention is widely used in verification of taximeters.

Description

A kind of measuring method of doughnut correction factor

Technical field

The present invention relates to a kind of metering method, the method that particularly relates to the method for ultrasonic ranging and obliquity sensor angle measurement is in conjunction with the measuring method that constitutes tire correction factor in the taximeter calibrating.

Background technology

Substantially all be to adopt simulated roadway at present, carry out the have the records of distance by the log calibrating of error of taximeter with the mode of cylinder, be specially: adopt the fee register of forming by cylinder, control system, the frame error calibrating installation of having the records of distance by the log, cylinder uses stainless steel, wear-resistant, the girth of cylinder generally is designed to 1 meter.During calibrating, the driving wheel carrier of taxi is on cylinder, rotating drive taxi wheel by the control system head roll rotates synchronously, reach the effect that simulating hires a car travels, the number of turns of measuring the cylinder rotation just can accurately obtain the mileage that cylinder rotates, contrast the measured value of having the records of distance by the log of fee register with this, realize the have the records of distance by the log calibrating of error of fee register.

Use the mode of cylinder to examine and determine fee register, floor area is little, handled easily, but adopt curved surfaces (circumferential surface of cylinder) to replace the road surface, plane of actual travel during owing to calibrating, the deformation difference of automotive wheel on these two kinds of geometric configuration objects, cause very big influence, promptly had the tire correction factor.The tire correction factor is meant that wheel rotates the pairing distance travelled of a fixing turn fee register in the plane, rotates the ratio of the pairing distance travelled of same number of turns fee register with wheel on curved surfaces.By a large amount of experiments, the tire correction factor can reach more than 2%, if do not revise then have a strong impact on the confidence level of fee register calibrating, so the accuracy of tire correction factor is the key factor of fee register calibrating control.

Do not have special-purpose tire correction factor measurement mechanism at present, generally adopt general survey instrument such as steel tape to measure, labour intensity is big, and personal error is big, and accuracy is not high.

The physical quantity that the tire correction factor is measured has two: stroke (distance) and corner.

Ultrasonic ranging is a kind of non-contact distance-measurement mode commonly used, and its measuring principle is that to utilize the aerial velocity of propagation C of ultrasound wave be known, measures the time T that ultrasound wave is propagated in testing distance L, presses physical equation L=C * T computed range.As the ultrasonic ranging accuracy, key is the accuracy of time T accuracy of measuring and the velocity of sound C that is obtained.Wherein for velocity of sound C, generally be to use, but in fact, the velocity of sound is relevant with the characteristic of the medium of propagating by physical constant, such as the composition of medium, temperature of medium or the like, when in air, propagating, just relevant with the temperature of air, air pressure etc.At present the ultrasonic range finder research field all research how accurately the characterisitic parameter (as temperature) of measuring media improve the accuracy of ultrasonic ranging so that velocity of sound C is revised.But this correcting mode, one is subjected to the accuracy limitations of the parameter of surveying, and two the mathematical model that the velocity of sound influences is limited by this characterisitic parameter, and three are subjected to the restriction of velocity of sound Study on influencing factors.

Simultaneously, ultrasonic ranging is to measure between fixed two measurement points, and the stroke measurment point of tire correction factor needs just can determine two measurement points behind running car, if will realize measuring automatically the problem that needs to consider to measure abbe ' s principle.

Obliquity sensor can accurately be measured the inclination angle under static state, but the outer corner measurement of tire correction factor is to carry out under dynamically, needs to solve the problem of successive dynamic measuring.Simultaneously, the actual state during owing to measurement can not guarantee vertical measurement face, needs to adopt three axial rake sensors to solve the problem that influences of verticality.

Summary of the invention

In order to solve above-mentioned technical matters, the objective of the invention is to solve artificialization of doughnut correction factor measuring process, adopt ultrasound wave comparative measurement method measuring distance, and stroke is measured in the correction that realizes the measurement abbe ' s principle, the influence of adopting the dynamic rotational angle of three axial rake sensor measurements simultaneously and solving verticality, provide a kind of doughnut correction factor automatically, accurate measuring method.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of measuring method of doughnut correction factor, this method comprises the steps:

A. the emission element of supersonic range finder is positioned on automobile headstock position, auxiliary target is placed on about 15m place, the place ahead, two setting height(from bottom) differences are arranged but the ultrasonic receiver of fixed distance on the auxiliary target, be called the target receiver and compare receiver, after auxiliary target and emission element are aimed at, measure distance L 1 and the ultrasonic velocity C of emission element to auxiliary target target receiver;

B. with the angle measurement parts of three axial rake sensors be positioned on the automotive wheel center near, and make the X-direction level, obtain zero starting point inclination angle;

C. start the taxi low speed driving, the angle measurement parts detect the rotation number of turns n of wheel, travel behind 5 circles, stop and stop automobile, and distance member is measured to distance L 2, the r of auxiliary target target receiver and comparison receiver, and the angle measurement parts are measured the terminal point inclination alpha;

D. remove distance measuring equipment, another angle measurement parts are installed near the rotating shaft of fee register use error calibrating installation cylinder, taxi drives wheel carrier on cylinder, and makes two angle measurement parts X-direction levels, obtains zero starting point inclination angle;

E. start the taxi low speed driving, detect rotation number of turns n1, the n2 of wheel and cylinder, travel behind 5 circles, stop and stop automobile, measure terminal point angle of inclination beta and γ;

F. according to the above-mentioned data computation tire correction factor S that surveys, formula is

Wherein

α _r=α+n * 360 °, β _r=β+n1 * 360 °, γ _r=γ+n2 * 360 °.

Be further used as preferred embodiment, in the step A, the ultrasonic receiver that two setting height(from bottom) differences and fixed distance are arranged on the described auxiliary target, setting height(from bottom) difference 2d is that 20mm to 40mm and target receiver position are low, two receivers are 0.5m to 1.0m at a distance of Lr, and these data need accurately to demarcate.

Be further used as preferred embodiment, in the step A, described aligning is that a parallel laser indication device is installed in the middle of the setting height(from bottom) of two receivers, the height of adjusting auxiliary target with this laser indication device is in the transmitter of distance measuring equipment and realizes on the laser guidance light aiming at, and what realize that two receivers depart from index line (being slotted line) is 10mm to 20mm apart from d.

Be further used as preferred embodiment, in the step A, the mode of described measuring distance L1 is after the measurement ultrasound wave is transmitted to the time T 11 of target receiver and extremely compares the time T 12 of receiver from transmitter, to press

Calculate.

Be further used as preferred embodiment, in the step B, described angle measurement parts be positioned on the automotive wheel center near, and need not be installed on the rotation axis of wheel.

Be further used as preferred embodiment, in described B, D step, described angle measurement parts X-axis need be carried out horizontal adjustment, and measures the output valve Y (V0) of angle measurement parts Y-axis under this state.

Be further used as preferred embodiment, in the step C, described distance member measure to receiver relatively apart from r, press

Calculate.

Be further used as preferred embodiment, in described C, E step, described measurement terminal point inclination angle is output valve X (Vout), Y (Vout), the Z (Vout) that measures the angle measurement component triaxial under this state, when the Z axle sensor is in ± 45 ° the time, presses

Calculate inclination alpha, when the X-axis sensor is in ± 45 ° the time, presses

Calculate inclination alpha, wherein

Be further used as preferred embodiment, in the step D, another angle measurement parts be installed near the rotating shaft of described fee register use error calibrating installation cylinder.

The present invention adopts the self-correcting comparative measurement method to realize the correction of acoustic velocity value, and this measuring method is a comparative method for measuring, does not have velocity of sound C in the measurement, does not promptly need acoustic velocity value, does not more have the correction to the velocity of sound.Only need to guarantee to measure under same environment simultaneously, this is guaranteed by measuring flow process.

The invention has the beneficial effects as follows: the present invention has avoided the problem of acoustic velocity value by the mode of two ultrasonic receivers, need not carry out the measurement of acoustic velocity value correction, has reduced the physical quantity of measuring; As the constant of measuring, its accuracy has improved the accuracy of measuring than with the constant height of acoustic velocity value as measurement with the distance between ultrasound wave target receiver and comparison receiver (relatively distance); The mode that adopts ultrasonic transmitter to separate with receiver than having improved reliability in the echometric measurement mode, and has increased the measurement range more than a times under square one; Adopt ultrasound wave target receiver and compare the ultrasonic signal that receiver receives same transmitter, the signal discriminating conveniently, accurately; Adopt the target receiver and the dual receiver mode of receiver relatively, the correction of measuring Abbe error can be measured actual running car stroke, realizes automatic stroke measurment under the situation that the starting point and the terminal point that do not need stroke manually identify; Under the slow-speed of revolution, use 3-axis acceleration sensor, the installation site of sensor need not be contained on the axis of wheel rotation, realized non-coaxial mounting means measurement rotational angle, metering system is simple and reliable, has solved the operability difficult problem of the coaxial installing angle sensor of automotive wheel; Adopt the verticality correcting mode, made the installation site of sensor not have the requirement of verticality, only needed to adjust horizontal level, processing ease.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples.

Fig. 1 is a measurement scheme synoptic diagram of the present invention;

Fig. 2 is a relative method ultrasonic ranging schematic diagram;

Fig. 3 is relative method ultrasonic measurement geometric model figure;

Fig. 4 measures the Abbe error synoptic diagram;

Fig. 5 is a triangulation model of measuring stroke;

Fig. 6 is an angle measurement component installation state synoptic diagram.

Embodiment

A kind of measuring method of doughnut correction factor, this method comprises the steps:

A. the ultrasonic ranging emission element is positioned on automobile headstock position, auxiliary target is placed on about 15m place, the place ahead, the ultrasonic receiver (be called the target receiver and compare receiver) that two setting height(from bottom) differences and fixed distance are arranged on the auxiliary target, setting height(from bottom) difference 2d is that 20mm and target receiver position are low, and two receivers are 0.5m (these data need accurately to demarcate) at a distance of Lr.One parallel laser indication device is installed in the middle of the setting height(from bottom) of two receivers, and the height of adjusting auxiliary target with this laser indication device is in the transmitter of distance measuring equipment and realizes aligning on the laser guidance light.The range finding emission element sends ultrasonic signal to the ultrasonic ranging auxiliary target, and starts time set simultaneously; After two ultrasonic sensors of ultrasonic ranging auxiliary target receive ultrasonic signal, send infrared signal to the range finding emission element respectively; After the ultrasonic ranging parts receive two wireless signals that send of ultrasonic ranging auxiliary target respectively, the triggering timing device, measure ultrasound wave from transmitter be transmitted to the time T 11 of target receiver and ultrasound wave is transmitted to the comparison receiver from transmitter time T 12 backs by Calculate the distance L 1 of emission element, press to auxiliary target target receiver

Calculate real-time ultrasound wave sound speed C.

B. with the angle measurement parts of three axial rake sensors be positioned on the automotive wheel center near, adjust the installation site of three axial rake sensors, adopt the voltage measurement device to monitor and make that the inclination angle of X-axis is zero, obtain zero first primary dip, and measure and write down the output voltage values Y (V0) of Y-axis simultaneously, be used for the automatic correction of verticality.

C. start taxi low speed driving (speed is lower than 5km/h), in the process of moving, the X, the Z axle output signal that adopt counter, four to segment and debate to circuit measuring three axial rake sensors are carried out the measurement of wheel number of turns n; Travel behind 5 circles, stop and stop automobile, measure ultrasound wave by the mode of above-mentioned A step and be transmitted to the time T 21 of target receiver and, press to the time T 22 of receiver relatively from transmitter

With

Calculate emission element to the distance L 2 of auxiliary target target receiver and to receiver relatively apart from r.After adopting the voltage measurement device to measure three output voltage values X (Vout), the Y (Vout) of current location three axial rake sensors, Z (Vout), mode by coordinate system transformation, be projected to angle behind the vertical guide as inclination alpha with the X-axis sensor, computing formula is as follows;

$\cos \left(\mathrm{\α}\right)=\frac{Y\left(V0\right)-Y\left(\mathrm{offset}\right)}{Y\left(S\right)}\×\frac{Y\left(V_{\mathrm{out}}\right)-Y\left(\mathrm{offset}\right)}{Y\left(S\right)}+\frac{Z\left(V0\right)-Z\left(\mathrm{offset}\right)}{Z\left(S\right)}\×\frac{Z\left(V_{\mathrm{out}}\right)-Z\left(\mathrm{offset}\right)}{Z\left(S\right)}$ Formula (1)

Or:

$\cos \left(\mathrm{\α}\right)=\frac{Y\left(V0\right)-Y\left(\mathrm{offset}\right)}{Y\left(S\right)}\×\frac{Y\left(V_{\mathrm{out}}\right)-Y\left(\mathrm{offset}\right)}{Y\left(S\right)}+$

$\frac{Z\left(V0\right)-Z\left(\mathrm{offset}\right)}{Z\left(S\right)}\×\sqrt{1-{\left(\frac{X\left(V_{\mathrm{out}}\right)-X\left(\mathrm{offset}\right)}{X\left(S\right)}\right)}^2-{\left(\frac{Y\left(V_{\mathrm{out}}\right)-Y\left(\mathrm{offset}\right)}{Y\left(S\right)}\right)}^2}$

Formula (2)

Current location Z axle sensor is in ± and 45 ° the time, adopt formula (1) to calculate the inclination angle, current location X-axis sensor is in ± and 45 ° the time, adopt formula (2) to calculate the inclination angle;

In the above-mentioned formula:

X (offset), Y (offset), Z (offset): the zero output voltage value of three axial rake sensors X axles, Y-axis, Z axle is the eigenwert of sensor, demarcates in advance;

X (S), Y (S), Z (S): the output sensitivity of three axial rake sensors X axles, Y-axis, Z axle under the plumbness is the eigenwert of sensor, demarcates in advance;

D. remove distance measuring equipment, another angle measurement parts are installed near the rotating shaft of fee register use error calibrating installation cylinder, taxi drives wheel carrier on cylinder, adjust the installation site of two angle measurement parts, adopt the voltage measurement device to monitor and make that the inclination angle of X-axis is zero, obtain zero first primary dip, and measure and write down Y-axis output valve Y (V0) simultaneously, be used for the automatic correction of verticality.

E. start the taxi low speed driving, detect rotation number of turns n1, the n2 of wheel and cylinder, travel behind 5 circles, stop and stop automobile, measure terminal point angle of inclination beta and γ by the mode of above-mentioned C step by the mode of above-mentioned C step;

F, be calculated as follows tire correction factor S:

In the formula: 1: the have the records of distance by the log cylinder girth of error calibrating installation of fee register, need to demarcate in advance, be generally 1m.

$L=\sqrt{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1}^2+\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1\&CenterDot;\mathrm{Lr}-({{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}^2+r^2)\frac{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1}{\mathrm{Lr}}+{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}2}^2}$

α _r＝α+n×360°

β _r＝β+n1×360°

γ _r＝γ+n2×360°

In conjunction with the accompanying drawings key principle is elaborated:

Measurement scheme of the present invention is as shown in Figure 1: adopt three axial rake sensors (1), revise (2) and segmentation automatically and debate the accurate measurement (4) that realizes continuous rotational angle to circuit (3) based on verticality; Adopt ultrasonic wavelength-division to penetrate the auxiliary target (6) of device (5) and dual receiver, method is measured apart from (7) and triangulation model (8) and is realized stroke measurment (9) accurately based on the comparison, thereby realizes the accurate measurement (10) of tire correction factor in the taximeter calibrating.

Relative method ultrasonic ranging principle of the present invention is as follows:

Adjust the distance L1 and L2 (when establishing L2＞L1) and adopting ultrasound wave mode measuring distance, then:

L1=C1 * T1 formula (3)

L2=C2 * T2 formula (4)

C is the velocity of sound in the formula, and T1, T2 are the time that ultrasound wave self-emission device is transmitted to receiver;

If guarantee to measure under same environment simultaneously, then C1=C2 establishes L=L1, L2=L+Lr, and the conversion by to formula (3) and (4) obtains:

This measuring method is a comparative method for measuring, does not have velocity of sound C in the measurement, does not promptly need acoustic velocity value, does not more have the correction to the velocity of sound.Only need to guarantee to measure under same environment simultaneously, this is solved by measuring flow process.This measuring method is many measured value Lr, this is the difference Lr between measured target and comparison object distance, for distance difference Lr, adopt the mode of two ultrasonic receivers to be solved, two receivers are installed on the object that is called auxiliary target, the spacing Lr of two receivers (relatively distance) is known through measuring (demarcation), thereby realizes comparing and measuring.By the technical capability of distance demarcation at present, the demarcation accuracy of reference distance L r can reach more than 0.02%.

During specific implementation, as shown in Figure 2, ultrasonic transmitter is in A point position, and ultrasound wave target receiver is in B point position, and ultrasound wave comparison receiver is in Br point position, and AB is testing distance L, and BBr is comparison distance L r.A in theory, B, 3 of Br in line the time accuracy of measurement the highest, if but like this then before receiver B will block back receiver Br, make receiver Br can not directly receive ultrasound wave, therefore be designed to 3 not measurement geometric models of conllinear, as shown in Figure 3, A and B, the central point of Br constitutes the dimensional measurement model of slotted line in line, B, Br departs from slotted line and is recommended as 10mm apart from d, this slotted line is by being installed in sighting device on the auxiliary target (in the implementation case, with the high brightness laser pen as sighting device) position, boresight is exactly this slotted line, and the range finding computing formula of bringing thus is:

$L=\sqrt{{(\mathrm{Lr}\&CenterDot;\frac{T_1}{T_2-T_1})}^2-{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}$

Stroke measurment Abbe error correction principle of the present invention is as follows:

Range observation in the tire correction factor, it is the distance that measured automobiles is travelled, metering system is to adopt an object, distance L 1 before automobile starting between measured automobiles and object, the distance L 2 between measured automobiles and object once more after automobile stops to obtain the distance L of running car according to the difference of these two distances, as shown in Figure 4, be difficult to this three of control in practice in line, bring because the caused Abbe error of triangle relation, i.e. L ≠ L1-L2.

Owing to adopt the measurement scheme of dual receiver, can revise Abbe error exactly:

As shown in Figure 5, measure the distance L 1 of B between an A and impact point at the running car before measurement, the reference distance L r by known can obtain acoustic velocity value C accurately; Automobile even without the direction according to AB, stops at actual terminal point A ' to overtake, and can measure distance L 2 between terminal point A ' and impact point B this moment, and terminal point A ' and comparison receiver Br apart from r.Owing to the direction of running car does not form an angle ∠ Br in the direction of AB, so the distance of running car can not subtract L2 with L1, i.e. L ≠ L1-L2.But, can obtain distance L very accurately according to cosine formula:

Diabolo △ AA ' Br:

$\cos \mathrm{Br}=\frac{{(\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1+\mathrm{Lr})}^2+r^2-{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}}^2}{2(\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1+\mathrm{Lr})\&CenterDot;r}$

Diabolo △ BA ' Br

$\cos \mathrm{Br}=\frac{{\mathrm{<figure-callout\; id="2"\; label="Lr"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">Lr</figure-callout>}}^2+r^2-{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}2}^2}{2\mathrm{Lr}\&CenterDot;r}$

Through mathematical operation, can get:

$L=\sqrt{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1}^2+\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1\mathrm{Lr}-({{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}^2+r^2)\frac{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}1}{\mathrm{Lr}}+{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">L</figure-callout>}2}^2}$

In the formula:

$r=\sqrt{{(C\&times;T_{22})}^2-{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HSA00000474280000011.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}$

The principle of three axial rake sensor measurement rotational angles of the present invention is as follows:

The measurement model of obliquity sensor is:

$\mathrm{\&alpha;}=\arcsin \frac{V_{\mathrm{out}}-\mathrm{offset}}{S}$

In the formula: α: the angle of inclination of relative surface level, (°);

Vout: the output voltage values of obliquity sensor, (V);

Offset: the output voltage values of obliquity sensor when zero inclination angle, (V);

S: the output sensitivity of obliquity sensor, (V/g).

Because obliquity sensor only has higher accuracy of measurement in-45 °～+ 45 ° inclination angle scopes, therefore use the Z axle of diaxon obliquity sensor realize-90 °～-45 ° ,+the accurate measurement at 45 °～+ 90 ° of inclination angles, and realize 0 °～360 ° four-quadrant measurements simultaneously, because automobile is to travel in the plane, it is constant that X, Z axial rake sensor are projected to the inclination angle relation of vertical guide, therefore adopts X, Z axle sensor to realize that the four-quadrant measurement of angle is accurately.

Because obliquity sensor need be installed on the wheel, but the installation site is irregular, can not guarantee that obliquity sensor can be perpendicular to rotational plane, though can adopt adjusting mechanism realizes, but because three-dimensional adjuster complex structure is huge, therefore only adopt one dimension only to adjust horizontal level, but the same problem that exists perpendicular to rotational plane, as shown in Figure 6.Inclination has taken place in former two axle sensors (Ox and Oz) that should measure wheel vertical guide OABC rotational angle, because wheel rotates with axletree, axletree is parallel ground, wheel is made circumference and is rotated on vertical guide, but sensor then is that (hyperboloid Oxx ' and hyperboloid Ozz ') rotates on the dip plane, sensor inclination angle with respect to the horizontal plane then is not an angle of circumference, can not accurately measure the rotational angle of wheel.Adopt three axial rake sensors,, then can carry out verticality and revise automatically according to the principle of coordinate transform as long as guarantee when the X-axis horizontal level, to obtain the incident angle of other diaxon.During installation, the X-axis obliquity sensor points to the wheel working direction, and the Y-axis obliquity sensor points to axial direction, the top of Z axial rake sensor directed in orthogonal direction.

Under rotary state, thereby centrifugal acceleration will produce the measurement accuracy that radial acceleration influences the free acceleration of obliquity sensor, but, the applied rotary state of the present invention only needs X, Z axle output voltage curve because measuring, segment and debate the number of turns of rotating by four to circuit measuring, do not need under the rotary state inclination angle value accurately, as long as centrifugal acceleration is not destroyed the shape of output voltage curve.Owing to using down at low speed (being lower than 5km/h), centrifugal acceleration is not more than 0.2g, and therefore employing is taken back stagnant comparator circuit realization four segmentations and then eliminated centrifugal acceleration fully to rotating the influence that the number of turns is measured.

More than be that preferable enforcement of the present invention is specified, but the invention is not limited to described embodiment, those of ordinary skill in the art also can make all equivalent variations or replacement under the prerequisite of spirit of the present invention, modification that these are equal to or replacement all are included in the application's claim institute restricted portion.

Claims (9)

1. the measuring method of a doughnut correction factor, it is characterized in that: this method comprises the steps:

A. the emission element of supersonic range finder is positioned on automobile headstock position, auxiliary target is placed on about 15m place, the place ahead, two setting height(from bottom) differences are arranged but the ultrasonic receiver of fixed distance on the auxiliary target, be called the target receiver and compare receiver, after auxiliary target and emission element are aimed at, measure distance L 1 and the ultrasonic velocity C of emission element to auxiliary target target receiver;

B. with the angle measurement parts of three axial rake sensors be positioned on the automotive wheel center near, and make the X-direction level, obtain zero starting point inclination angle;

C. start the taxi low speed driving, the angle measurement parts detect the rotation number of turns n of wheel, travel behind 5 circles, stop and stop automobile, and distance member is measured to distance L 2, the r of auxiliary target target receiver and comparison receiver, and the angle measurement parts are measured the terminal point inclination alpha;

D. remove distance measuring equipment, another angle measurement parts are installed near the rotating shaft of fee register use error calibrating installation cylinder, taxi drives wheel carrier on cylinder, and makes two angle measurement parts X-direction levels, obtains zero starting point inclination angle;

E. start the taxi low speed driving, detect rotation number of turns n1, the n2 of wheel and cylinder, travel behind 5 circles, stop and stop automobile, measure terminal point angle of inclination beta and γ;

F. according to the above-mentioned data computation tire correction factor S that surveys, formula is

Wherein

α _r=α+n * 360 °, β _r=β+n1 * 360 °, γ _r=γ+n2 * 360 °.

2. the measuring method of a kind of doughnut correction factor according to claim 1, it is characterized in that: in the step A, the ultrasonic receiver that two setting height(from bottom) differences and fixed distance are arranged on the described auxiliary target, setting height(from bottom) difference 2d is that 20mm to 40mm and target receiver position are low, two receivers are 0.5m to 1.0m at a distance of Lr, and these data need accurately to demarcate.

3. the measuring method of a kind of doughnut correction factor according to claim 1, it is characterized in that: in the step A, described aligning is that a parallel laser indication device is installed in the middle of the setting height(from bottom) of two receivers, the height of adjusting auxiliary target with this laser indication device is in the transmitter of distance measuring equipment and realizes on the laser guidance light aiming at, and what realize that two receivers depart from index line (being slotted line) is 10mm to 20mm apart from d.

4. the measuring method of a kind of doughnut correction factor according to claim 1, it is characterized in that: in the step A, the mode of described measuring distance L1 is after the measurement ultrasound wave is transmitted to the time T 11 of target receiver and extremely compares the time T 12 of receiver from transmitter, to press

Calculate.

5. the measuring method of a kind of doughnut correction factor according to claim 1 is characterized in that: in the step B, described angle measurement parts be positioned on the automotive wheel center near, and need not be installed on the rotation axis of wheel.

6. the measuring method of a kind of doughnut correction factor according to claim 1 is characterized in that: in described B, D step, described angle measurement parts X-axis need be carried out horizontal adjustment, and measures the output valve Y (V0) of angle measurement parts Y-axis under this state.

7. the measuring method of a kind of doughnut correction factor according to claim 1 is characterized in that: in the step C, described distance member measure to receiver relatively apart from r, press

Calculate.

8. the measuring method of a kind of doughnut correction factor according to claim 1, it is characterized in that: in described C, E step, described measurement terminal point inclination angle is output valve X (Vout), Y (Vout), the Z (Vout) that measures the angle measurement component triaxial under this state, when the Z axle sensor is in ± 45 ° the time, presses

Calculate inclination alpha, when the X-axis sensor is in ± 45 ° the time, presses

Calculate inclination alpha, wherein

9. the measuring method of a kind of doughnut correction factor according to claim 1 is characterized in that: in the step D, another angle measurement parts are installed near the rotating shaft of described fee register use error calibrating installation cylinder.

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