CN110539708A - Wheel and parameter measurement method for wheel - Google Patents

Abstract

The invention discloses a wheel, which includes a rim and a tire installed on the rim, a range finder is installed on the outer surface of the rim, and the outer surface of the rim and the tire are measured in real time by the range finder The radial distance of the inner surface. During the movement of the vehicle, the rangefinder rolls along with the rim, and measures the distance between the outer surface of the rim and the inner surface of the tire at a certain frequency in real time, and transmits the distance value to the vehicle controller in real time, which is the vehicle dynamics control. Provides tire rolling radius parameters. On this basis, a parameter measurement method for the wheel and the vehicle are also provided.

Description

Wheel and parameter measurement method for wheel

technical field

The invention relates to a wheel and a parameter measuring method for the wheel.

Background technique

The existing technology can only measure the rotational speed of the wheel, but cannot measure the rolling radius of the tire, so the linear velocity of the tire at the contact point cannot be accurately calculated.

The reasons for these shortcomings and problems are as follows:

When the vehicle is in motion, the tire deforms under the load of the vehicle, causing the rolling radius of the tire to be different from its inflated radius in the free state. Therefore, using the inflated radius in the free state to replace the rolling radius has a large error.

At this stage, due to the inability to timely grasp the ground contact status and stress of the tires during the driving process of the car, the control accuracy of the car's maneuverability is not high, and many dangerous working conditions cannot be warned in advance. Especially in the dangerous working condition of the wheels slipping, the car cannot give early warning and can only deal with it passively.

Contents of the invention

The object of the present invention is to provide a wheel to solve the above-mentioned technical problems in the prior art.

The wheel provided by the present invention includes a rim and a tire installed on the rim, a range finder is installed on the outer surface of the rim, and the outer surface of the rim and the inner surface of the tire are measured in real time by the range finder radial distance.

Further, the rim, the tire and the distance meter rotate coaxially.

Further, the range finder is a range sensor.

Further, the range finder is mounted on the outer surface of the rim by bonding.

Further, the rangefinder is installed on the outer surface of the rim in a mechanical connection.

Further, the range finder is installed on the outer surface of the rim by using a connecting piece.

Further, the connecting member is a bolt or a pin.

Further, the distance meter is installed at the center of the outer surface of the rim.

The wheel provided by the invention has the following advantages:

During the movement of the vehicle, the rangefinder rolls along with the rim, and measures the distance between the outer surface of the rim and the inner surface of the tire at a certain frequency in real time, and transmits the distance value to the vehicle controller in real time, which is the vehicle dynamics control. Provides tire rolling radius parameters.

Moreover, the tire will be periodically deformed during the rolling process, so the value of the distance between the outer surface of the rim and the inner surface of the tire measured by the rangefinder will change periodically during the process of one revolution. The rotation period, from which the rotational speed of the wheel can be calculated.

In addition, the present application also provides a parameter measurement method for the above wheel, comprising the following steps:

Measure the radial distance between the outer surface of the rim and the inner surface of the tire within one rotation cycle of the wheel to obtain multiple distance parameters and corresponding tire rotation angles;

Obtaining a radial distance function of the outer surface of the rim and the inner surface of the tire as a function of time from the function of the tire rotation angle as a function of time and the plurality of distance parameters and the corresponding tire rotation angle;

According to the fixed radius of the rim and the function, the function of the rolling radius of the tire with respect to time can be obtained, thereby obtaining the real-time rolling radius of the tire.

Further, according to the difference between the free radius of the tire and the rolling radius of the tire, the sinking amount of the tire under the current load is obtained;

The free radius of the tire is the contour radius of the tire under a standard inflation pressure under zero load.

Further, according to the free radius of the tire and the rolling radius of the tire, the length of the tire contact patch is calculated.

Further, within one rotation of the tire, the frequency of measuring the radial distance between the outer surface of the rim and the inner surface of the tire is _f0 , and the time interval between two consecutive measurements is calculated according to the frequency _f0 ;

According to the length of the contact footprint and the time interval, the rolling speed of the tire is calculated. The parameter measuring method for above-mentioned wheel provided by the present invention has following advantages:

Through a simple sensor integration system, the calculation of tire rolling radius, tire sinkage, tire contact footprint, tire rolling speed and tire vertical load in automobile control can be realized, especially the real-time and accurate measurement of tire rolling radius , greatly improving the vehicle dynamics control accuracy.

In addition, the present application also provides an automobile, including the above wheel.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the specific embodiments or prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic structural diagram of a wheel provided by an embodiment of the present invention.

Fig. 2 is a schematic diagram of the parameter geometric relationship of the parameter measurement method for the wheel provided by the embodiment of the present invention.

FIG. 3 is a theoretical output signal diagram of a range finder for a parameter measurement method for a wheel provided by an embodiment of the present invention.

Reference numerals: 1-ground; 2-tyre; 3-rim; 4-distance meter; 5-connector.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, or in a specific orientation. construction and operation, therefore, should not be construed as limiting the invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Embodiment one:

Fig. 1 is a schematic structural view of a wheel provided by an embodiment of the present invention; as shown in Fig. 1 , the wheel provided by Embodiment 1 of the present invention includes a rim 3 and a tire 2 mounted on the rim 3, and the outer surface of the rim 3 A range finder 4 is installed on the surface, and the radial distance between the outer surface of the rim 3 and the inner surface of the tire 2 is measured in real time by the range finder 4 .

Specifically, the rim 3, the tire 2 and the rangefinder 4 rotate coaxially.

Specifically, the distance measuring instrument 4 is a distance measuring sensor.

Specifically, the range finder 4 is installed on the outer surface of the rim 3 by means of bonding or mechanical connection.

Preferably, the rangefinder 4 is mounted on the outer surface of the rim 3 by using a connecting piece 5 .

Specifically, the connecting member 5 is a bolt or a pin.

It should be noted that the bolts or pins for the connecting member 5 are only used for illustration, and other connecting members can also be used, which will not be exemplified here.

Specifically, the distance meter 4 is installed at the center of the outer surface of the rim 3 .

The wheel provided by this embodiment has the following advantages:

During the movement of the vehicle, the range finder 4 rolls along with the rim 3, and measures the distance between the outer surface of the rim 3 and the inner surface of the tire 2 in real time at a certain frequency, and transmits the distance value to the controller of the vehicle in real time, for The vehicle dynamics control provides the tire rolling radius parameter, which provides the real-time rolling radius of the wheel.

Moreover, the radius of the tire 2 will be deformed periodically during the rolling process, so the distance between the outer surface of the rim 3 and the inner surface of the tire 2 will change periodically when the rangefinder 4 rotates for one week. This period is the rotation period of the tire 2, and the rotational speed of the wheel can be calculated accordingly.

In addition, according to the rotational speed and the real-time rolling radius of the wheel, the real-time linear velocity of the wheel can be obtained. It is also possible to obtain the inflation pressure state of the tire through calculation according to the change of the radius of the tire.

Embodiment two:

Fig. 2 is a schematic diagram of the parameter geometric relationship of the parameter measurement method for the wheel provided by the embodiment of the present invention; Fig. 3 is a range finder output signal diagram of the parameter measurement method for the wheel provided by the embodiment of the present invention; as shown in Fig. 2- As shown in Fig. 3, the parameter measurement method for the wheel provided by the second embodiment includes the following steps:

Measure the radial distance between the outer surface of the rim and the inner surface of the tire within one rotation cycle of the wheel to obtain multiple distance parameters and corresponding tire rotation angles;

Obtaining a radial distance function of the outer surface of the rim and the inner surface of the tire as a function of time from the function of the tire rotation angle as a function of time and the plurality of distance parameters and the corresponding tire rotation angle;

According to the fixed radius of the rim and the function, the function of the rolling radius of the tire with respect to time can be obtained, thereby obtaining the real-time rolling radius of the tire.

It is also possible to obtain the sinkage of the tire under the current load according to the difference between the free radius of the tire and the rolling radius of the tire;

The free radius of the tire is the contour radius of the tire under a standard inflation pressure under zero load.

Alternatively, the length of the tire contact patch can be calculated according to the free radius of the tire and the rolling radius of the tire.

Also, within one rotation of the tire, the frequency of measuring the radial distance between the outer surface of the rim and the inner surface of the tire is _f0 , and the time interval between two consecutive measurements is calculated according to the frequency _f0 ;

According to the length of the contact footprint and the time interval, the rolling speed of the tire is calculated.

Specifically, the measurement frequency of the range finder 4 is f ₀ , and since the tire 2 rolls periodically on the ground 1, the measured distance parameter is a set of discrete sampling data d(t), and the sampling frequency is f ₀ , the period is T;

The time interval Δt=1/f ₀ between two consecutive samples can be calculated by the sampling frequency;

The real-time radial distance between the tire 2 and the rim 3 is defined as the intersection point P of the line connecting the installation point center D of the rangefinder 4 on the rim 3 and the center point O of the rim 3 with the tire 2, and the distance of the line segment PD is defined as the The distance d(t) between the rim 3 and the tire 2 at any moment, this value changes continuously with the rolling deformation of the tire 2, which is the rotation angle of the tire 2 function, because So d(t) is a function of measurement time;

The necessary known design parameters of tire 2 and rim 3 in the calculation process are defined as follows:

The vertical stiffness parameter Cz of the tire 2, the vertical stiffness of the tire 2 is defined as the ratio of the vertical load Fz on the tire 2 to the sinking amount ds of the tire 2 under the standard inflation pressure, C _z =F _z /d _s .

The free radius R of the tire 2 is the contour radius of the tire 2 under the standard inflation pressure and the load is 0. At this time, the tire 2 is an approximately ideal circle, and the free radius R is equal everywhere;

The radius r of the rim 3 is the outer radius of the rim 3 used with the tire 2, and this parameter is equal everywhere;

The target calculation parameters are defined as follows:

The rolling radius Rd of the tire 2 is the vertical distance from the center point of the rim 3 to the ground 1 during the rolling process of the tire 2 under the standard air pressure Pr and a certain load Fz;

The rolling speed V of the tire 2 and the forward speed V of the center of the tire 2 are defined by the following formula: V=Rd*ω;

The sinkage ds of the tire 2 is the difference between the free radius R of the tire 2 and its rolling radius Rd under the standard air pressure and a certain load Fz working condition of the tire 2, that is, the distance ds that the center point of the tire 2 drops after bearing the load, which satisfies Equation: ds=R-Rd;

The length of the ground contact mark L, the maximum value of the mark formed by the ground contact of the tire 2 in the rolling direction of the tire 2;

Vertical load Fz of tire 2, the vertical load on tire 2, unit N, the load should be designed within a certain range under the condition of safe driving of tire 2, if the load is too large, it means that tire 2 is overloaded, and there are safety hazards such as tire blowout. If the load is too small or close to 0, it means that the tire 2 will leave the ground 1 at this time, and there is a potential safety hazard of rollover or loss of control;

Target parameter calculation method.

Theoretical curve derivation of range finder 4 distance measurement signal value d(t);

Assuming that the range finder 4 is located directly under the rim 3 at the initial moment, then:

The angles at the intersection point P of the extension line connecting the center line between the rangefinder 4 and the center of the rim 3 and the tire 2 leave the ground 1 and enter the ground 1 are respectively The time is t0, t1 respectively, and the theoretical equation of distance d(t) measured by rangefinder 4 during one rotation of tire 2 is as follows:

d(t)=Rr; t∈[t ₀ ,t ₁ ]

Calculation method description:

Figure 3 shows the theoretical output signal diagram of the rangefinder 4. In the actual test process, the signal output by the rangefinder 4 contains a large number of noise components. Therefore, before the calculation of subsequent parameters, the output distance signal must be d(t) performs filter processing to identify the ideal approximate signal curve shown in Figure 3, and then calculates subsequent parameters on this basis;

Rolling radius Rd calculation method:

From the law of rotation of the tire 2, it can be seen that when the air pressure and load of the tire 2 remain unchanged, the data d(t) measured by the rangefinder 4 changes periodically. The distance d is the minimum value dmin of the ranging signal d(t), the rolling radius of the tire 2 is the sum of the radius of the rim 3 and the distance between the rim 3 and the tire 2, and the rolling radius Rd can be calculated by the following formula;

R _d =r+min(d(t)),t∈[0,T]

Calculation method of subsidence

After calculating the tire 2 rolling radius Rd, the tire 2 sinkage ds can be calculated from the definition of the tire 2 sinkage, and the sinkage parameter ds can be calculated by the following formula:

d _s =R-Rd

Where R is the free radius of tire 2, and Rd is the rolling radius of tire 2;

Calculation method of tire 2 ground contact footprint:

Calculation method of tire 2 rolling speed V:

The time interval between the fixed point P on the tire 2 entering the ground 1 and leaving the ground 1 is:

Δt=t0+T-t1

During this period of time, the moving distance of point P on tire 2 is equal to the length of the footprint, so the forward speed of tire 2 can be calculated as:

V=L/Δt

Calculation method of vertical load Fz of tire 2:

_{Fz = Czds} .

The parameter measuring method for above-mentioned wheel provided by the present invention has following advantages:

Realized the calculation of tire 2 rolling radius, tire 2 sinkage, tire 2 ground contact footprint, tire 2 rolling speed and tire 2 vertical load in automobile control, especially realized the real-time and accurate measurement of tire 2 rolling radius, which greatly improved The accuracy of vehicle dynamics control is improved.

Embodiment three:

The present application also provides an automobile, including the above-mentioned wheel.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (12)

1. a wheel is characterized by comprising a rim and a tire mounted on the rim, wherein a distance meter is mounted on the outer surface of the rim, and the radial distance between the outer surface of the rim and the inner surface of the tire is measured in real time through the distance meter.

2. a wheel according to claim 1, wherein said rim, said tyre and said distance meter rotate coaxially.

3. a wheel according to claim 1, wherein said distance meter is a distance measuring sensor.

4. A wheel according to claim 1, wherein the distance meter is adhesively mounted on the outer surface of the rim.

5. A wheel according to claim 1, wherein the distance meter is mounted on the outer surface of the rim by means of a mechanical connection.

6. a wheel according to claim 5, wherein the distance meter is mounted on the outer surface of the rim using a connector.

7. a wheel according to claim 6, wherein said connection is a bolt or a pin.

8. The wheel of claim 1, wherein the rangefinder is mounted centrally on the outer surface of the rim.

9. a parameter measuring method for a vehicle wheel according to any one of claims 1-8, comprising the steps of:

Measuring the radial distance between the outer surface of the rim and the inner surface of the tyre during one rotation cycle of the wheel to obtain a plurality of distance parameters and corresponding tyre rotation angles;

Obtaining a function of the radial distance of the outer rim surface and the inner tire surface with respect to time from the function of the tire rotation angle with respect to time and the plurality of distance parameters and the corresponding tire rotation angle;

from the fixed radius of the rim and the function, a function of the rolling radius of the tire with respect to time can be obtained, thus obtaining the real-time rolling radius of the tire.

10. The parameter measuring method for a wheel according to claim 9, wherein the amount of sinking of the tire under the current load is obtained from the difference between the free radius of the tire and the rolling radius of the tire;

the free radius of the tire is the profile radius of the tire under a condition of zero load at a standard inflation pressure.

11. The parameter measurement method for a wheel according to claim 9, wherein the tire footprint length is calculated from a free radius of the tire and a rolling radius of the tire.

12. a parameter measuring method for a wheel according to claim 11, wherein the radial distance between the outer surface of the rim and the inner surface of the tyre is measured during one revolution of the tyre at a frequency f0, and the time interval between two consecutive measurements is calculated from the frequency f 0;

and calculating the rolling speed of the tire according to the length of the footprint and the time interval.