KR20190043689A - Apparatus and method for monitoring condition of vehicle tires - Google Patents

Abstract

The present invention provides a system for monitoring a condition of a tire, which comprises: a piezoelectric sensor unit for transmitting a signal value output from a piezoelectric element which is attached to an inner surface of a sidewall of a tire in the same or different form to a control unit; and the control unit for comparing the signal value received from the piezoelectric sensor unit via wireless communication with a predetermined deformation value and controlling an alarm signal to be displayed when the signal value is larger than the deformation value. According to the present invention, a driver can be protected by precisely determining whether tire vibration is caused by a defect of a road surface or a standing wave to warn the driver and prevent damage to the tire while driving a vehicle in advance.

Description

TECHNICAL FIELD [0001] The present invention relates to a tire condition monitoring system and method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire condition monitoring system and method, and more particularly, to a tire condition monitoring system and method capable of monitoring deformation of a tire using a piezoelectric sensor and a distance sensor.

In order to provide driver safety and convenience, the vehicle is equipped with a vehicle radar, a tire pressure monitoring system (TPMS), a remote start device, and a geographic information system. Tires are parts that come in direct contact with the road so that the power of the vehicle is transmitted to the road surface. The condition of the tire is directly related to the safety of the driver. An important factor in monitoring the condition of the tire is air pressure, and the air pressure sensor (TPMS) senses the air pressure and temperature in the tire in real time and informs the driver through the instrument panel.

The air pressure sensing device is divided into a direct mode and an indirect mode. The direct mode is a TPMS type in which a sensor is attached to an air injection valve of a tire, and is composed of a microcontroller (MCU), a pressure sensor, a temperature sensor, an RF transmitter and a battery. The indirect method can monitor the air pressure state of the tire based on information on the number of revolutions of the wheel obtained from the anti-look break system (ABS). Recently, a direct TPMS has been mounted on the vehicle have.

On the other hand, when the tire is tilted at a constant speed (for example, 150 Km / s or more) at a high speed under low air pressure, the centrifugal force of the tread of the tire and the air pressure inside the tire cause the tire to become convex immediately after falling from the ground, A standing wave phenomenon may be generated. The tires can not withstand the centrifugal force at the time of traveling while standing waves are generated and are damaged, causing a serious accident while driving.

In the prior art related to the present invention, Korean Patent Laid-Open Publication No. 10-2014-0067431, entitled " Tire defect warning device ", discloses a tire defect warning device in which a piezoelectric sensor is mounted on a tire, And informs the driver of the repair or replacement of the tire. However, in the prior art, only the change of tire wear and tensile force is judged based on the signal value outputted from the piezoelectric sensor, and only the repair and replacement of the tire are described before driving. There is not disclosed a technique for detecting a standing wave phenomenon of a tire and informing the driver of the standing wave phenomenon so as to prevent an accident caused by a standing wave in actual driving.

Therefore, it is possible to detect the deformation of the tire according to the standing wave during driving and to inform the driver of the deformation of the tire in advance, and to prevent accidents in advance. Also, by monitoring the wheel alignment state and the wheel balancing state, Systems, and methods.

Korean Patent Laid-Open Publication No. 10-2014-0067431 (June 4, 2014)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a steering system capable of detecting a deformation of a tire according to a standing wave during driving, The present invention is to provide a tire condition monitoring system and a tire condition monitoring method that can prevent the abnormal wear of a tire from occurring.

According to an aspect of the present invention, there is provided a tire condition monitoring system including a tire condition monitoring system for detecting a tire condition, the tire condition monitoring system comprising: And a control unit for comparing the signal value received from the piezoelectric sensor unit via the sensor unit and the wireless communication with a predetermined deformation value and controlling the display unit to display an alarm signal when the signal value is greater than the deformation value.

The piezoelectric element according to an embodiment of the present invention is a band-shaped flexible piezoelectric element having a predetermined width, and includes a piezoelectric layer for generating electricity according to vibration, a piezoelectric layer formed on the piezoelectric layer, And an isolation layer formed on the adhesive layer and separated to expose the adhesive layer to the outside.

The piezoelectric element according to an embodiment of the present invention includes a first piezoelectric element attached to one side of a sidewall of one tire along a circumference in a single integrated first attachment form and a second piezoelectric element attached to the other side of the sidewall with a predetermined length And a second piezoelectric element attached in a second attaching manner independent of each other.

The control unit compares the signal value received from the first piezoelectric element with a predetermined deformation value and determines whether the signal value is greater than the deformation value and the signal values received from the second piezoelectric element And displays a warning to decelerate the vehicle when there is a difference or periodic change.

The controller may further include a distance sensor attached to the rim of the tire according to an embodiment of the present invention to transmit a signal value corresponding to the deformation of the tire to the controller, And calculating a flatness ratio and a deformation ratio of the tire, comparing the calculated flatness ratio and deformation ratio with a predetermined flatness ratio and a deformation ratio, and judging the wheel alignment state and the wheel balancing state.

According to the present invention as described above, it is possible to precisely determine whether the tire vibration is caused by a failure of the road surface during running or a tire vibration by the standing wave, and warns the driver, thereby preventing the tire from being damaged during traveling, . Also, it is possible to prolong the life of the tire by judging the wheel alignment state, the tire deformation and the wheel deformation through the piezoelectric sensor and the distance sensor to prevent abnormal wear of the tire in advance.

1 is a block diagram of a configuration of a tire condition monitoring system according to an embodiment of the present invention.
2A and 2B are views showing the attachment of a piezoelectric sensor to a tire according to an embodiment of the present invention.
3 is a view showing a configuration of a piezoelectric sensor according to an embodiment of the present invention.
4 is a view showing the attachment of a distance sensor to a tire according to an embodiment of the present invention.
5A and 5B are flowcharts for explaining the operation of the tire condition monitoring system according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention and methods of achieving them will be apparent with reference to the embodiments described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below, but may be implemented in various forms. In the following embodiments, the terms first, second, and the like are used for the purpose of distinguishing one element from another element, not the limitative meaning. Also, the singular expressions include plural expressions unless the context clearly dictates otherwise. Also, the terms include, including, etc. mean that there is a feature, or element, recited in the specification and does not preclude the possibility that one or more other features or components may be added. Also, in the drawings, for convenience of explanation, the components may be exaggerated or reduced in size. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or corresponding components throughout the drawings, and a duplicate description thereof will be omitted .

1 is a block diagram of a configuration of a tire condition monitoring system according to an embodiment of the present invention.

As shown in FIG. 1, the tire condition monitoring system 1000 includes a tire sensor unit 100 that acquires signal values according to air pressure, temperature, vibration, and deformation of a tire from a plurality of sensors mounted on the tire, And a control unit 200 for comparing the signal value received from the tire sensor unit with a preset signal value to determine the state of the tire.

The tire sensor unit 100 may include a sensor capable of sensing air pressure, temperature, vibration, and deformation (tire condition) of the tire, and a sensor controller capable of processing signal values measured from the sensor. The sensor control unit includes a microcontroller (MCU) for receiving the sensor signal values according to the state of the tire to be measured and converting the sensor signal values into a digital signal, and an RF transmitter And a battery for supplying power. The wireless communication unit 150 may transmit the signal value measured by the tire sensor unit 100 to the wireless communication unit 260 of the control unit 200 through short-range wireless communication such as Bluetooth, infrared rays or ZigBee. The wireless communication unit 150 may be included in each sensor unit.

The pressure sensor unit 130 and the temperature sensor unit 140 for detecting the air pressure or the temperature of the tire may be composed of an air pressure sensing device (TPMS). The piezoelectric sensor unit 110 includes piezoelectric materials for generating electric charges by vibrations generated from the tire in accordance with the running of the tire, a microcontroller for processing signals generated from the piezoelectric devices and transmitting the processed signals to the control unit 200, And a wireless communication unit. The piezoelectric sensor unit 110 can store the voltage output from the piezoelectric element in the battery through the power management circuit, and the energy stored in the battery can be used as a driving power source for the piezoelectric sensor unit. The piezoelectric sensor can be attached to the tire to detect the deformation of the tire when traveling, and the shape of the piezoelectric sensor, the position of attachment of the tire, the attachment form, and the like will be described in detail with reference to FIGS. The distance sensor unit 110 can measure the width of the tire and the distance to the height of the tire according to changes in load, speed, air pressure, etc. during stopping. The distance sensor unit 110 may include a light emitting sensor and a light receiving sensor, and the attachment position and distance detection of the distance sensor unit 110 will be described in detail with reference to FIG.

The control unit 200 includes an output unit 240 for monitoring the state of the tire in real time using the signal value received from each sensor unit through the wireless communication unit 260 and displaying the monitored tire state information on an alarm or an instrument panel, To the driver. The control unit 200 includes a vehicle control state unit 210, a tire state determination unit 220, a vehicle control unit 230, an output unit 240, and a control unit 240. The vehicle control unit 210 manages information on current driving conditions such as vehicle speed and steering position. Memory 250 may be included. The tire state determination unit 220 can determine the state of the tire by comparing the signal value received from each sensor unit with a lookup table stored in advance in the memory 250. [ The vehicle control unit 230 may receive the control command according to the currently determined tire condition and may control the vehicle to decelerate the vehicle speed. For example, when the tire state determination unit 220 determines that the tire deformation value exceeds a preset deformation value (i.e., it is determined that a standing wave phenomenon will occur during driving), the vehicle control unit 230 controls the acceleration device The speed can be controlled to be automatically reduced. The memory 250 may store a look-up table preset according to the air pressure, the temperature, the tire deformation value, the tire flatness ratio, etc. with respect to the steady state of the tire according to the current vehicle specification. The lookup table may be information on a range of allowable tire deformation or tire flatness ratio according to the tire pressure, which is a tire state element, and information on the flatness ratio of the tire according to the steering condition of the tire. The description of the standing wave judgment and the tire flatness ratio and the deformation ratio using the piezoelectric element of the tire condition determination unit 220 of the control unit will be described in detail with reference to FIGS. 5A and 5B.

When the vehicle is running at a constant speed (for example, 150 Km / s), when the tire air pressure is low, the tire is deformed by the air pressure of the tire. For example, when the tire air pressure is low, the driver may be warned by the tire air pressure sensor (TPMS). However, when the vehicle runs at a constant speed (for example, 150 Km / s) And it is inevitably exposed to the risk of being subjected to a major accident. Therefore, a tire condition monitoring system using a piezoelectric sensor capable of monitoring a state change of a tire during running in real time to inform the driver that a standing wave can occur will be described in detail with reference to FIGS. 2A to 3 and 5A.

FIGS. 2A and 2B are views showing the attachment of a piezoelectric sensor to a tire according to an embodiment of the present invention, and FIG. 5A is a flowchart for explaining the operation of the tire condition monitoring system according to an embodiment of the present invention.

2A, the piezoelectric element 111 can be attached to the inner rubber layer of the side wall of the tire. The piezoelectric elements 111 may be attached in the form of a single integrated first attachment along the circumference of the sidewall (see (a)), or may have a second preferred form (See (b)). That is, the piezoelectric element 111 can be attached to the side wall of the tire in which the most deformation occurs due to the standing wave phenomenon when traveling while the tire air pressure is low. Referring to FIG. 2B, the first piezoelectric element 111a may be attached to the inside of the left side wall of the tire, and the second piezoelectric element 111b may be attached to the right side of the opposite side wall. Here, the first piezoelectric element 111a and the second piezoelectric element 111b attached to one tire have the same attachment form or the first piezoelectric element 111a is attached to the one integrated first attachment form The second piezoelectric element 111b is attached in a different form to each of the independent second attachment forms, and the first signal value and the second signal value according to the respective attachment forms can be transmitted to the tire condition determination unit of the control unit have.

The piezoelectric sensor unit 110 can transmit the first signal value and the second signal value generated according to the first and second attachment types to the tire state determination unit 220 of the control unit through wireless communication (S51 Reference). When the signal value is larger than the deformation value, the tire condition determining unit 220 compares the first signal value according to the first mounting type with a preset deformation value in the memory, and when the signal value is larger than the deformation value, . On the other hand, when it is determined that the first signal value received from the piezoelectric sensor unit 110 is larger than a preset deformation value, the tire state determination unit 220 may be uncertain whether the determination is based on an irregular road surface state or a standing wave . Accordingly, when the first signal value is greater than a preset deformation value, the tire state determination unit 220 continuously compares the second signal value (signal values measured from the respective independent piezoelectric elements) It is possible to determine that the second wave is a standing wave when the second wave is consecutive in the second wave and the second wave has a preset difference value. That is, referring to FIG. 2A, the standing wave generates a strong vibration on the circumference of the sidewall of the tire immediately after the tire is separated from the ground, so that the tire state determiner 220 determines the continuous part (a, b, c , d and e may have a signal value larger than the second signal values of other consecutive parts f, g, h, i, j, it can be determined as a standing wave. As a method of determining another standing wave, the tire state determination unit 220 measures the change of the second signal values inputted in a predetermined measurement time range, and when the measured signal value has a predetermined period and the size of the signal value is If it changes, it can be judged as a standing wave (refer to S53 in Fig. 5A). Accordingly, the tire state determination unit 220 determines that the first signal value input from the piezoelectric element having a different attachment form to one tire and the signal group continuous at a specific time point of the second signal value are different from the difference Or whether the second signal value changes with a predetermined period, and can accurately determine a standing wave that occurs due to a low air pressure that does not depend on the state of the road surface, and can display a warning to the driver (see S55 in FIG. 5A) . The vehicle control unit 230 can receive the control command according to the currently determined tire state and control the vehicle to decelerate the vehicle speed (refer to S57 in FIG. 5A).

Referring to FIG. 3, the piezoelectric element 111 may be formed of a band-shaped flexible piezoelectric element having a predetermined width. The piezoelectric element 111 can transmit electricity generated by the vibration to the microcontroller 112 of the piezoelectric sensor unit and the battery through the electric wire 20 connected to an electrode layer (not shown) connected to the piezoelectric layer. The piezoelectric sensor part may be mounted on a wheel of a tire in the form of a tire air pressure sensor (TPMS) or mounted on a printed circuit board of an air pressure sensor (TPMS). The length L of the piezoelectric element 111 may have a predetermined length depending on the first attachment form and the second attachment form. The flexible piezoelectric element 111 includes a piezoelectric layer 115 for generating electricity according to vibration using a piezoelectric composite material combining a piezoelectric polymer (EAP: Electroactive Polymer), a piezoelectric polymer and a ceramic material, and a nano wire, An adhesive layer 115 formed on the piezoelectric layer and made of epoxy, cement, glue or the like to urge the piezoelectric layer on the surface of the tire, and a separating layer 117 formed on the adhesive layer and separated from the adhesive layer to externally expose the adhesive layer ). Therefore, the piezoelectric element 111 can be easily attached to the rubber layer in the side wall of the tire after removing the separation layer because the adhesive layer is formed on the piezoelectric layer. It is possible to prevent the piezoelectric element from being separated from the tire surface by vibration by applying a sealing material made of silicone or rubber having flexibility to the piezoelectric element attached to the inside of the side wall, though not shown.

FIG. 4 is a diagram illustrating the attachment of a distance sensor to a tire according to an embodiment of the present invention, and FIG. 5B is a flowchart illustrating an operation of the tire condition monitoring system according to an embodiment of the present invention.

4, the distance sensor unit 120 may be attached to the outer surface of the rim 321 of the tire. The distance sensor unit 120 includes a light emitting sensor and a light receiving sensor. The height H of the tread of the tire contacting the road surface, The signal value obtained by measuring the width W of the month can be transmitted to the control unit through wireless communication. The distance sensor 120 is a distance sensor for measuring the distance of a specific point. The light sensor senses the light propagated from the light emitting sensor and can measure the distance using the used moving time. The ultrasonic sensor, A radar sensor, and a light sensor. The distance sensor unit 120 may transmit the measured signal value to the tire condition determiner of the controller through the wireless communication unit (see S61 in FIG. 5B). The tire state determination unit can calculate the deformation ratio by calculating the flatness ratio by dividing the tire height H by the cross-sectional width W of the tire using the received signal values (H, W) and comparing it with a preset flatness ratio. The tire condition determiner can continuously determine the wheel alignment state and the wheel balancing state by comparing the calculated flatness and deformation ratio with the preset flatness ratio and deformation ratio. If the tire condition determining unit does not match the preset flatness ratio and deformation ratio, it is determined that the wheel alignment state and the wheel balancing state are abnormal (refer to S63 in Fig. 5B), and an alarm notification or an instrument panel is displayed to notify the driver (See S65 of FIG. Meanwhile, the tire state determination unit can determine the abnormal state of the tire while driving by referring to the vehicle steering information acquired from the vehicle control state unit, and comparing the predetermined ratio of the flatness and the deformation ratio according to the steering information to the calculated flatness ratio and deformation ratio. That is, the tire condition sensing unit determines the wheel alignment and wheel balancing defects by using the tire flatness ratio and the deformation ratio measured through the distance sensor unit, and notifies the driver of the deficiency of the wheel alignment and wheel balancing, thereby preventing the abnormal wear of the tire in advance. . Also, it is possible to calculate the flatness ratio and the deformation ratio of the tire according to the load weight during stopping, and calculate the weight of the vehicle by comparing the flatness ratio and deformation ratio according to the preset load weight.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, I will understand.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the appended claims.

100: tire sensing unit 110: piezoelectric sensor unit
111, 111a, 111b: Piezoelectric element 112: Sensor processing part
115: piezoelectric layer 116: adhesive layer
117: separation layer
120: distance sensor unit 130: pressure sensor unit
140: temperature sensor unit 150: wireless communication unit
200:
210: vehicle control state unit 220: tire state judgment unit
230: vehicle control unit 240: output unit
250: memory 260:
311: tire tread 312: tire side wall
320: Wheel 321: Rim
1000: Tire condition monitoring system

Claims (5)

A piezoelectric sensor unit for transmitting a signal value output from a piezoelectric element which is attached to the inner surface of the sidewall of the tire in the same shape or in different forms to the control unit;
And a control unit for comparing the signal value received from the piezoelectric sensor unit via wireless communication with a predetermined deformation value and controlling the display unit to display an alarm signal when the signal value is larger than the deformation value.
The method according to claim 1,
The piezoelectric element is a band-shaped flexible piezoelectric element having a predetermined width,
A piezoelectric layer for generating electricity according to vibration,
An adhesive layer formed on the piezoelectric layer and for attaching the piezoelectric layer to the surface of the tire and
And a separation layer formed on the adhesive layer and separated to expose the adhesive layer to the outside.
3. The method of claim 2,
The piezoelectric element includes a first piezoelectric element attached to one side of a sidewall of a tire in a single integrated first attachment form along a circumference, and a second piezoelectric element having a predetermined length at the other side of the sidewall, And a second piezoelectric element attached to the first piezoelectric element.
The method of claim 3,
The control unit compares the signal value received from the first piezoelectric element with a predetermined deformation value and if the signal value is larger than the deformation value and there is a difference or a periodic change between the signal values received from the second piezoelectric element And displays a warning to decelerate the speed of the vehicle.
The method according to claim 1,
And a distance sensor unit attached to the rim of the tire to transmit a signal value corresponding to the deformation of the tire to the control unit,
The control unit calculates a flatness ratio and a deformation ratio of the tire by using the signal value received from the distance sensor through wireless communication, and compares the calculated flatness ratio and deformation ratio with a predetermined flatness ratio and deformation ratio to determine the wheel alignment state and the wheel balancing state Of the tire condition monitoring system.

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