KR20220088964A - Vehicle speed estimation system and estimation method thereof - Google Patents

Abstract

The present invention relates to a vehicle speed estimation system and a method for estimating the same, and more particularly, to a vehicle speed estimation system for more accurately estimating a vehicle speed and a method for estimating the same. In order to achieve the above object, the present invention includes: a sensor module mounted on a tire and measuring a radial acceleration signal according to the rotation of the rotating tire; a receiver module for receiving the radial acceleration signal measured by the sensor module; a filtering module for filtering the radial acceleration for estimating the traveling speed of the vehicle from the radial acceleration signal received by the receiver module; and an analysis module configured to estimate the traveling speed of the vehicle using the radial acceleration filtered by the filtering module and the radius of the tire.

Description

VEHICLE SPEED ESTIMATION SYSTEM AND ESTIMATION METHOD THEREOF

The present invention relates to a vehicle speed estimation system and a method for estimating the same, and more particularly, to a vehicle speed estimation system for more accurately estimating a vehicle speed and a method for estimating the same.

The vehicle stability control device (Electronic Stability Program, ESP) and vehicle motion control device using sensing in the vehicle is a 2-DOF inertial sensor (lateral acceleration, yaw rate) or 3-DOF inertial sensor (longitudinal acceleration, lateral acceleration, yaw rate). ) to estimate the vehicle's speed.

Although this estimation process is effective when driving on flat ground, it is difficult to accurately estimate the speed in the non-linear tire friction section where there is a lateral inclination angle or large longitudinal/lateral sliding.

In addition, the vehicle speed estimation technique using the conventional inertial sensor has a possibility of divergence of the estimated value.

To improve this, a technology for estimating the speed of a vehicle using a steering angle sensor and a wheel speed sensor such as Korean Patent Registration No. 10-1543156 has been developed.

However, these technologies have a problem in that they require additional equipment in addition to the sensor.

In addition, in the case of a technology for estimating the driving speed of a vehicle using GPS, there is a problem in that it does not work when passing through a tunnel or an underpass.

Korean Patent Registration No. 10-1543156

SUMMARY OF THE INVENTION An object of the present invention to solve the above problems is to provide a vehicle speed estimation system for more accurately estimating the vehicle speed and a method for estimating the same.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. There will be.

In order to achieve the above object, the present invention includes: a sensor module mounted on a tire and measuring a radial acceleration signal according to the rotation of the rotating tire; a receiver module for receiving the radial acceleration signal measured by the sensor module; a filtering module for filtering the radial acceleration for estimating the traveling speed of the vehicle from the radial acceleration signal received by the receiver module; and an analysis module configured to estimate the traveling speed of the vehicle using the radial acceleration filtered by the filtering module and the radius of the tire.

In an embodiment of the present invention, the sensor module may be formed on an inner liner of the tire.

In an embodiment of the present invention, the filtering module may be configured to represent the measured radial acceleration signal as an acceleration waveform graph over time, and to extract a ground area of the tire from the acceleration waveform graph.

In an embodiment of the present invention, the ground area may be provided to extract a difference between a minimum value and a maximum value of a differential value in the acceleration waveform graph as a ground area.

In an embodiment of the present invention, the filtering module may be provided to filter the radial acceleration when the sensor module is located opposite to the center of the extracted ground area.

In an embodiment of the present invention, the analysis module calculates the square root of a value obtained by multiplying the radius of the tire by the radial acceleration when the sensor module is located on the opposite side of the center of the extracted ground area as the driving speed of the vehicle. It may be characterized in that it is provided to estimate.

According to an aspect of the present invention, there is provided a vehicle speed estimation method of a vehicle speed estimation system, comprising: a) measuring a radial acceleration signal according to the rotation of a tire; b) receiving the measured radial acceleration signal; c) filtering the radial acceleration signal for estimating the driving speed of the vehicle from the radial acceleration signal received by the receiver module; and d) estimating the driving speed of the vehicle using the filtered radial acceleration and the radius of the tire.

In an embodiment of the present invention, the step c) includes: c1) displaying the measured radial acceleration signal as an acceleration waveform graph over time; c2) extracting a ground area of the tire from the acceleration waveform graph; and c3) filtering the radial acceleration when the sensor module is located opposite to the center of the extracted ground area.

In an embodiment of the present invention, the step c2) may be characterized in that a difference between a minimum value and a maximum value of a differential value in the acceleration waveform graph is extracted as the ground region.

In the embodiment of the present invention, in step d), the square root of a value obtained by multiplying the radius of the tire by the radial acceleration when the sensor module is located on the opposite side of the center of the extracted ground area is calculated as the driving speed of the vehicle. It may be characterized in that it is provided to estimate .

According to the effect of the present invention according to the above configuration, the driving speed of the vehicle can be estimated only by the sensor attached to the tire.

Therefore, power consumption due to additional equipment for estimating driving speed can be reduced, and since sensing is performed inside the tire, which is most closely related to speed, accurate speed estimation is possible even in a section where GPS is not available.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a block diagram of a vehicle speed estimation system according to an embodiment of the present invention.
2 is a graph of an acceleration waveform according to an embodiment of the present invention.
FIG. 3 is an exemplary view showing the position of a sensor module that has measured each radial acceleration in the acceleration waveform graph of FIG. 2 .
4 is a flowchart of a vehicle speed estimation method of a vehicle speed estimation system according to an embodiment of the present invention.
5 is a flowchart of a step of filtering radial acceleration according to an embodiment of the present invention.
6 is a graph showing the radial acceleration for each speed of an 18-inch tire according to an embodiment of the present invention.
7 is a graph comparing the running speed estimated by the vehicle speed estimation method of the vehicle speed estimation system according to an embodiment of the present invention and the running speed of a tire set in the tester.
8 is a graph comparing the driving speed estimated by the vehicle speed estimation method of the vehicle speed estimation system according to an embodiment of the present invention and the vehicle speed recorded by GPS.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be “connected (connected, contacted, coupled)” with another part, it is not only “directly connected” but also “indirectly connected” with another member interposed therebetween. "Including cases where In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

The terminology used herein is used only to describe specific embodiments, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a vehicle speed estimation system according to an embodiment of the present invention.

As shown in FIG. 1 , the vehicle speed estimation system 100 includes a sensor module 110 , a receiver module 120 , a filtering module 130 , and an analysis module 140 .

The sensor module 110 may be mounted on the inner liner of the tire, and may be provided to measure a radial acceleration signal according to the rotation of the rotating tire.

At this time, the mounting position of the sensor module 110 is not limited to the inner liner.

In addition, the radial acceleration may refer to an acceleration in a radial direction of the tire.

The receiver module 120 may be provided to receive the radial acceleration signal measured by the sensor module 110 . In addition, the receiver module 120 may be provided to provide the received radial acceleration signal to the filtering module 130 .

In addition, the receiver module 120 may be provided to control the transmission and reception of information between the filtering module 130 and the analysis module 140 .

The filtering module 130 may be provided to filter the radial acceleration for estimating the driving speed of the vehicle from the radial acceleration signal received by the receiver module 120 .

FIG. 2 is an acceleration waveform graph according to an embodiment of the present invention, and FIG. 3 is an exemplary view showing the position of a sensor module measuring each radial acceleration in the acceleration waveform graph of FIG. 2 .

Specifically, referring to FIGS. 2 and 3 , the filtering module 130 may be provided to represent the measured radial acceleration signal as an acceleration waveform graph over time, and to extract a ground area of a tire from the acceleration waveform graph. have.

In this case, the ground region may be provided to extract a difference between a minimum value and a maximum value of a differential value in the acceleration waveform graph as a ground region.

For example, at the point (b) of FIG. 3 , the differential value forms a minimum value as the radial acceleration rapidly decreases as shown in (b) of FIG. 2 . Conversely, at the point (d) of FIG. 3, the differential value forms a maximum value, as shown in (d) of FIG. 2 . As such, points (b) to (d) of FIG. 3 are in a state where the tire and the road surface are grounded, and the filtering module 130 may be provided to derive the grounding area using a differential value.

In addition, the filtering module 130 may be provided to filter the radial acceleration when the sensor module 110 is located on the opposite side of the center of the extracted ground area.

Specifically, the central portions of (b) and (d) constituting the ground region in FIG. 3 are (c). Therefore, points (a) and (e) located opposite to (c) from the center of the tire have the least influence from the ground, and the linear speed is the most similar to the vehicle speed.

Accordingly, the filtering module 130 performs filtering to derive the radial acceleration having the least influence from the ground and the linear speed most similar to the driving speed of the vehicle in the section in which the tire rotates in the same way as described above. can be provided.

The analysis module 140 may be provided to estimate the driving speed of the vehicle using the radial acceleration filtered by the filtering module 130 and the radius of the tire.

Specifically, the speed of the tire moving in a circle and the magnitude of the radial acceleration may be defined by Equation 1 below.

(a is the radial acceleration, r is the radius of the tire, ω is the angular velocity, v is the linear velocity)

Here, in the present invention, the radial acceleration is filtered by the filtering module 130 at a position where the linear speed is most similar to the driving speed of the vehicle. Therefore, in Equation 1 above, v can be said to be a linear speed and a vehicle traveling speed.

Based on this, the analysis module 140 estimates the square root of a value obtained by multiplying the radius of the tire by the radial acceleration when the sensor module is located on the opposite side of the center of the extracted grounding area as the driving speed of the vehicle. can be provided.

Hereinafter, a vehicle speed estimation method of the vehicle speed estimation system will be described in more detail with reference to FIG. 4 .

4 is a flowchart of a vehicle speed estimation method of a vehicle speed estimation system according to an embodiment of the present invention.

Referring to FIG. 4 , in the vehicle speed estimation method of the vehicle speed estimation system, first, a step S10 of measuring a radial acceleration signal according to rotation of a tire may be performed.

In the step (S10) of measuring the radial acceleration signal according to the rotation of the tire, the sensor module 110 may be provided to continuously measure the radial acceleration signal with respect to the radial direction of the tire when the tire rotates. .

After the step ( S10 ) of measuring the radial acceleration signal according to the rotation of the tire, the step of receiving the measured radial acceleration signal ( S20 ) may be performed.

In the step of receiving the measured radial acceleration signal ( S20 ), the receiver module 120 may be provided to receive the radial acceleration signal measured by the sensor module 110 .

After receiving the measured radial acceleration signal (S20), filtering the radial acceleration for estimating the driving speed of the vehicle from the radial acceleration signal received by the receiver module (S30) may be performed. .

5 is a flowchart of a step of filtering radial acceleration according to an embodiment of the present invention.

5 , the step of filtering the radial acceleration for estimating the driving speed of the vehicle in the radial acceleration signal received by the receiver module ( S30 ) is, first, the measured radial acceleration signal according to time Step S31 represented by an acceleration waveform graph may be performed.

In the step (S31) of displaying the measured radial acceleration signal as an acceleration waveform graph over time, the filtering module 130 converts the radial acceleration signal received by the receiver module 120 to the radial acceleration over time. It can be expressed as an acceleration waveform graph, which is a graph.

After the step (S31) of displaying the measured radial acceleration signal as an acceleration waveform graph over time, a step (S32) of extracting a ground area of the tire from the acceleration waveform graph may be performed.

In the step of extracting the ground area of the tire from the acceleration waveform graph ( S32 ), the filtering module 130 may be provided to extract the ground area of the tire from the acceleration waveform graph.

In this case, the ground region may be provided to extract a difference between a minimum value and a maximum value of a differential value in the acceleration waveform graph as a ground region.

For example, at the point (b) of FIG. 3 , the differential value forms a minimum value as the radial acceleration rapidly decreases as shown in (b) of FIG. 2 . Conversely, at the point (d) of FIG. 3, the differential value forms a maximum value, as shown in (d) of FIG. 2 . As such, points (b) to (d) of FIG. 3 are in a state where the tire and the road surface are grounded, and the filtering module 130 may be provided to derive the grounding area using a differential value.

After extracting the ground area of the tire from the acceleration waveform graph (S32), a step (S33) of filtering the radial acceleration when the sensor module is located opposite the center of the extracted ground area may be performed.

In the filtering step (S33) of the radial acceleration when the sensor module is located opposite to the center of the extracted grounding area, the filtering module 130 is configured to the opposite side of the center of the extracted grounding area to the sensor module 110 ) may be provided to filter the radial acceleration when located.

Specifically, the central portions of (b) and (d) constituting the ground region in FIG. 3 are (c). Therefore, points (a) and (e) located opposite to (c) from the center of the tire have the least influence from the ground, and the linear speed is the most similar to the vehicle speed.

In this way, in the step (S30) of filtering the radial acceleration for estimating the driving speed of the vehicle in the radial acceleration signal received by the receiver module, the filtering module 130 is It may be arranged to perform filtering for deriving a radial acceleration having the least influence and a linear speed most similar to the traveling speed of the vehicle.

After the filtering of the radial acceleration for estimating the driving speed of the vehicle from the radial acceleration signal received by the receiver module (S30), the driving speed of the vehicle is estimated using the filtered radial acceleration and the radius of the tire step S40 may be performed.

In the step of estimating the driving speed of the vehicle using the filtered radial acceleration and the radius of the tire (S40), the analysis module 140 detects when the sensor module is located on the opposite side of the center of the extracted grounding area. It may be provided to estimate the square root of a value obtained by multiplying the radial acceleration and the radius of the tire as the driving speed of the vehicle.

6 is a graph showing the radial acceleration for each speed of an 18-inch tire according to an embodiment of the present invention.

More specifically, FIG. 6 shows the measurement of radial acceleration in a flat-trac tester at 30, 40, and 60 kph of an 18-inch tire. It can be seen that the tire driving speed is generally proportional to the radial acceleration.

In this case, when the radial acceleration is calculated by considering the radius of the tire as in the present invention, the driving speed of the vehicle can be more accurately estimated.

7 is a graph comparing the running speed estimated by the vehicle speed estimation method of the vehicle speed estimation system according to an embodiment of the present invention and the running speed of a tire set in the tester.

7 shows the driving speed of the vehicle estimated according to the present invention, and the comparative example means the driving speed set in the tester.

As shown in FIG. 7 , it can be confirmed that the estimated value and the traveling speed are similar.

Set speed (kph) Estimated speed (m/s) error(%) 30 8.2 -1.56 45 12.57 0.62 60 17.14 2.9

Table 1 above shows the speed error of the Example and Comparative Example of FIG. 7 . As shown in Table 1, it can be confirmed that the error between the set speed and the estimated speed is only within 3%.

8 is a graph comparing the driving speed estimated by the vehicle speed estimation method of the vehicle speed estimation system according to an embodiment of the present invention and the vehicle speed recorded by GPS.

In FIG. 8, Example 1 is a traveling speed estimated by the vehicle speed estimation method of the vehicle speed estimation system according to an embodiment of the present invention, and Example 2 is a graph of Example 1 linearly shown.

Comparative Example 1 is a traveling speed measured by GPS, and Comparative Example 2 is a graph of Comparative Example 1 shown linearly.

As shown in FIG. 8 , it can be confirmed that Examples 1 and 2 and Comparative Examples 1 and 2 are similar in the amount of change of the traveling speed with time.

time(s) Estimated speed (m/s) GPS speed (m/s) Error rate (%) 2 23.5524 24.9658 5.6613447 3 32.9373 34.3919 4.2294843 4 42.3222 43.818 3.4136656 5 51.7071 53.2441 2.8867048 6 61.092 62.6702 2.5182623 7 70.4769 72.0963 2.2461624 8 79.8618 81.5224 2.0369862

More specifically, referring to Table 2 above, it can be seen that the error rate between the estimated speed estimated by the method according to the present invention and the speed measured by GPS is close to within 6%. In particular, it can be seen that the error rate exceeds 5% at the initial stage of measurement, but the error rate decreases to less than 3% after the measurement time is 5 seconds.

Accordingly, according to the present invention prepared as described above, the traveling speed of the vehicle can be estimated only with the sensor attached to the tire. That is, it is possible to reduce the use of power due to additional equipment for estimating the driving speed.

In addition, since sensing is performed inside the tire, which is most closely related to speed, accurate speed estimation is possible even in tunnels or underpass sections where GPS cannot be used.

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

100: vehicle speed estimation system
110: sensor module
120: receiver module
130: filtering module
140: analysis module

Claims (10)

a sensor module mounted on the tire and measuring a radial acceleration signal according to the rotation of the rotating tire;
a receiver module for receiving the radial acceleration signal measured by the sensor module;
a filtering module for filtering the radial acceleration signal for estimating the driving speed of the vehicle from the radial acceleration signal received by the receiver module; and
and an analysis module configured to estimate the traveling speed of the vehicle using the radial acceleration filtered by the filtering module and the radius of the tire.
The method of claim 1,
The sensor module is
Vehicle speed estimation system, characterized in that formed on the inner liner of the tire.
The method of claim 1,
The filtering module,
representing the measured radial acceleration signal as an acceleration waveform graph over time,
The vehicle speed estimation system, characterized in that it is provided to extract a tire grounding area from the acceleration waveform graph.
4. The method of claim 3,
The ground area is
The vehicle speed estimation system according to claim 1, wherein a difference between a minimum value and a maximum value of a differential value in the acceleration waveform graph is extracted as a ground area.
4. The method of claim 3,
The filtering module,
Vehicle speed estimation system, characterized in that provided to filter the radial acceleration when the sensor module is located on the opposite side of the center of the extracted ground area.
6. The method of claim 5,
The analysis module is
The vehicle speed estimation system according to claim 1, wherein the square root of a value obtained by multiplying the radius of the tire by the radial acceleration when the sensor module is located on the opposite side of the center of the extracted grounding area is provided to estimate the running speed of the vehicle.
In the vehicle speed estimation method of the vehicle speed estimation system according to claim 1,
a) measuring a radial acceleration signal according to the rotation of the tire;
b) receiving the measured radial acceleration signal;
c) filtering the radial acceleration signal for estimating the traveling speed of the vehicle from the radial acceleration signal received by the receiver module; and
d) estimating the driving speed of the vehicle using the filtered radial acceleration and the radius of the tire.
8. The method of claim 7,
Step c) is,
c1) displaying the measured radial acceleration signal as an acceleration waveform graph over time;
c2) extracting a ground area of the tire from the acceleration waveform graph; and
c3) The method of estimating the vehicle speed of the vehicle speed estimation system comprising the step of filtering the radial acceleration when the sensor module is located opposite to the center of the extracted ground area.
9. The method of claim 8,
Step c2) is
and extracting a difference between a minimum value and a maximum value of a differential value in the acceleration waveform graph as the ground area.
9. The method of claim 8,
Step d) is,
The vehicle of the vehicle speed estimation system, characterized in that it is provided to estimate the square root of a value obtained by multiplying the radial acceleration and the radius of the tire when the sensor module is located on the opposite side of the center of the extracted grounding area as the running speed of the vehicle How to estimate speed.

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