KR20010047234A - Road State Estimation Apparatus - Google Patents

Abstract

PURPOSE: A road surface sensing device improves a running safety by sensing a road surface condition with a radar sensor to notify the condition to a driver. CONSTITUTION: A sensing device comprises a signal generator, a radar sensor(1), an alarm unit(7) and a main unit(8). The signal generator generates a millimeter wave. The radar sensor(1) computes a reflection coefficient by radiating the millimeter wave generated from the signal generator to a road surface and receiving the millimeter wave reflected by the road surface. The alarm unit(7) outputs a road surface condition alarm signal. The main unit(8) controls the alarm unit(7) by basing on an information, the kind and the thickness of a medium computed with the reflection coefficient computed from the radar sensor(1). Therefore, the sensing device senses the road surface condition more accurately and notifies the condition information to the driver.

Description

Road detection device {Road State Estimation Apparatus}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road surface detection device of a vehicle. In particular, unlike a conventional road surface detection device using a speed sensor of a vehicle and a speed sensor of a wheel, a radar sensor is used to provide a driver for driving safety speed, safety distance, and safe driving. The present invention relates to a road surface detection device that warns in advance to increase safety.

Nowadays, electronic control technology using various sensors is introduced so that the occupants of a vehicle that operates at high speed are safe. In particular, the driver can perform safe driving by automatically detecting the condition of the road surface and informing the driver. Various techniques are implemented.

As an example, the driving force control apparatus (notice No. 1991-004600) of a vehicle engine patented and registered at Mitsubishi Doshisha High School in Japan in 1988 includes a driving wheel speed detecting means for detecting a driving wheel speed of a vehicle and a vehicle body speed. On the basis of slip determination means for determining the slip of the driving wheel from the vehicle speed detection means, the output signal of the drive wheel detection means and the output signal of the vehicle speed detection means, and the slip start signal output from the slip determination means so as to reduce slips quickly Traction control means having an output rate calculating means for generating a second command for controlling the engine to produce an output corresponding to the friction coefficient between tires when the first command for controlling the output of the engine is generated and the slip is reduced to a predetermined value. And an engine output control number controlling an engine output based on the first and second commands and a driving state of the vehicle. The driving force control apparatus for a vehicle engine comprising a disclosure is described.

As another example, a road friction coefficient measuring device and method (published No. 1995-014859) filed in 1993 in the form of a brake switch, vehicle speed sensor, front wheel speed sensor, front wheel speed sensor, All-wheel solenoids and all-wheel solenoids are formed at the output, and a technology is disclosed in which a monitor is connected to a microcomputer in which data is input.

In general, the road surface detection device detects the wheel speed by installing a speed sensor for detecting the speed of the vehicle on the vehicle body and installing a wheel speed sensor on each wheel. The absolute speed of the vehicle is taken from the speed sensor, and the degree of slip of the wheel is calculated from each wheel speed taken from each wheel speed sensor, thereby detecting the road surface condition.

However, as described above, the conventional road surface sensing device detects a road surface state by directly contacting wheels on the road surface, and thus has a disadvantage in that sensors are installed on all four wheels of the vehicle.

Accordingly, the present invention has been made in order to solve the above-described problems, unlike the conventional road surface detection device using a speed sensor of the vehicle and the speed sensor of the wheel, by using the radar sensor to launch and receive a predetermined millimeter wave on the road surface It is an object of the present invention to provide a road surface detection device that can increase driving safety by detecting road conditions based on a signal and informing a driver of road conditions in advance.

1 is a conceptual diagram of a vehicle to which the road surface sensing apparatus according to the first embodiment of the present invention is applied.

FIG. 2 is a diagram illustrating installation of the road surface sensing antenna of FIG. 1. FIG.

3 is an electrical diagram of the road surface sensing apparatus of FIG. 1.

4 is a conceptual diagram in which the radar sensor and the road surface sensing antenna of FIG. 1 are connected by a waveguide.

FIG. 5 is a conceptual diagram of a millimeter wave reflection according to the medium of FIG. 1; FIG.

6 is an electrical configuration of a road surface detection apparatus according to a second embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

1: radar sensor 2: waveguide

3: outgoing antenna 4: receiving antenna

7: warning unit 8: main unit

10: oscillator 11: transmitter

12: Splitter 13, 15, 20: Envelope Detector

14, 16, 21: log-amp 17: switching unit

18: operator 19: inverse log-amplifier

32, 42, 52, 62: circulator 33, 43, 53, 63: mixer

35, 45, 55, 65: A / D converter

According to an aspect of the present invention, there is provided a road detecting device including: a signal generating unit configured to generate a millimeter wave by detecting a state of a road surface and executing a predetermined warning to a driver in a vehicle in progress; A radar sensor which emits a millimeter wave output from the signal generator on a road surface and receives a millimeter wave reflected by the road surface to calculate a reflection coefficient; A warning unit for outputting a road surface warning signal; And a main unit for controlling the warning unit based on the information calculated by calculating the type and thickness of the medium based on the reflection coefficient calculated by the radar sensor.

The radar sensor is an antenna for emitting a millimeter wave output from the signal generator and collects the reflected signal; A signal generator for generating a millimeter wave and transmitting it to the antenna; A first envelope detector for detecting an envelope of the millimeter wave generated by the signal generator; A divider for separating and outputting the millimeter wave received through the antenna into P-polarized wave and S-polarized wave; A second envelope detector for detecting the envelope of the P-polarized wave distributed in the distributor; A third envelope detector for detecting an envelope of the S-polarized wave distributed in the distributor; A first log amplifier for log amplifying an output signal of the first envelope detector; A second log-amplifier for log amplifying an output signal of the second envelope detector; A third log amplifier for log amplifying the output signal of the third envelope detector; A switching unit for alternately outputting output signals of the second and third log-amps according to a predetermined control signal of the main unit; An operator for calculating an output signal output from the first log amplifier and two signals switched from the switching unit and outputting a corresponding output signal; And an inverse log-amplifier which inversely amplifies the output signal of the operator to output a millimeter wave reflection coefficient.

The signal generation unit controls the driving of the vehicle by acquiring the obstacle information around the vehicle based on the signal emitted by the millimeter wave to the outside of the vehicle and reflected, and is shared as a signal source of the vehicle control device that alerts the presence of the obstacle. desirable.

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

1 is a conceptual diagram of a vehicle applied to a road surface sensing apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, the road surface sensing apparatus according to the present invention includes a radar sensor 1, a radar sensor 1, and a waveguide that generate a millimeter wave composed of P-polarized wave and S-polarized wave. (2) connected to (2) to emit a millimeter wave transmitted from the radar sensor (1) at a predetermined angle to the road surface to receive a reflection signal emitted from the transmission antenna (3), reflected from a predetermined medium On the basis of the reception antenna (4), the warning unit (7) for warning the state of the road surface by a predetermined warning means, the driving safety speed and the safety distance for the road situation based on the ratio of the incident wave and the reflected wave, that is, the reflection coefficient or the road surface The main unit 8 is configured to control the warning unit 7 to warn the driver in the event of a dangerous situation.

Reference numeral 5 is a throttle actuator, and 6 is a brake actuator.

FIG. 2 is a diagram illustrating installation of the transmitting antenna 3 and the receiving antenna 4 in FIG. 1. As shown in FIG. 2, the transmitting antenna 3 and the receiving antenna 4 are arranged at a predetermined angle so that the millimeter wave emitted through the transmitting antenna 3 is received through the receiving antenna 4.

3 is an electrical configuration diagram of the road surface sensing apparatus of FIG. 1.

As shown in FIG. 3, the road surface sensing apparatus of the present invention transmits the millimeter wave generated by the oscillator 10 and the oscillator 10 generating the millimeter wave (P-polarized wave and S-polarized wave) to the transmitting antenna 3. The transmitter 11, the transmitting antenna 3 for firing the millimeter wave into a predetermined region, the first envelope detector 20 for detecting the envelope of the millimeter wave (strength of the signal waveform) transmitted from the transmitter 11, and the transmitting A receiving antenna 4 for collecting signals reflected from the front road surface by a signal emitted from the antenna 3, a splitter 12 for splitting and outputting P-polarized wave and S-polarized wave among the received millimeter waves, and a divider 12 ), A second envelope detector 13 for detecting the envelope of the P-polarized wave, which is distributed from To log amplify the output signal The first log amplifier 21, the second log amplifier 14 for log-amplifying the output signal of the second envelope detector 13, the third log amplifier for log-amplifying the output signal of the third envelope detector 15 The amplifier 16, the switching unit 17 for selectively outputting the output signals of the second and third log-amps 14 and 16 in accordance with a predetermined control signal, and the output output from the first log-amp 21 And an inverse log-amplifier 19 which inversely amplifies the output signal of the operator 18 and an operator 18 for calculating a signal and two signals output from the switching unit 17 and outputting a corresponding output signal. It is composed. The signals output from the inverse log amplifier 19 mean the reflection coefficients for the media of each polarization.

4 is a conceptual diagram in which the radar sensor 1 and the road sensing antennas 3 and 4 in FIG. 1 are connected by waveguides. As shown in FIG. 4, the radar sensor 1 and the transmitting antenna 3 are connected to the waveguide 2 so that a millimeter wave is transmitted from the radar sensor 1 to the transmitting antenna 3.

FIG. 5 is a conceptual diagram illustrating millimeter wave reflection according to a medium shown in FIG. 1.

As shown in FIG. 5, when the millimeter wave generated from the radar sensor 1 propagates toward the road surface by the road detection transmitting antenna 3, the road surface (medium 3, permittivity) from the air layer (medium 1, permittivity ε ₁ ) ε ₃ ) is incident on water, ice, or snow (medium 2, permittivity ε ₂ ), and the predetermined millimeter wave becomes a reflected wave and is collected by the road surface sensing receiving antenna 4.

In this case, the amount of reflection varies depending on the medium (ice, snow, or water) on the road surface, which is formed from Fresnel's Formula as follows.

(R _p : reflectance of P-polarized wave, R _12p : reflectance at interface between medium 1 and medium 2 of P-polarized wave, R _23p : reflectance at interface between medium 2 and medium 3 of P-polarized wave, R _s : S Reflectance of polarization, R _12s : reflectance at the interface between medium 1 and medium 2 of S-polarization, R _23s : reflectance at the interface between medium 2 and medium 3 of S-polarization, d: thickness of medium 2 on the road surface , λ: wavelength of the millimeter wave, ε ₂ : dielectric constant of medium 2, θ ₂ : refractive angle of medium 2, ε ₁ : dielectric constant of medium 1, θ ₁ : refractive angle of medium 1, ε ₃ : dielectric constant of medium 3, θ ₃ : Refraction angle of medium 3)

Therefore, by measuring the incident amount (envelope of the signal) and the reflection amount (envelope of the signal) of the P-polarized wave and the S-polarized wave, the reflection coefficients R _p and R _s which are output data of the inverse log-amplifier in Fig. 3 are obtained. The main unit 8 can obtain the β value and the permittivity ε ₂ of the medium 2 from this reflection coefficient. The thickness d of the medium 2 (ice, snow or water) can be seen.

From this, it is possible to know what thickness (ice, snow, or water) on the road surface is accumulated and to determine the road surface condition. The main unit 8 controls the warning unit 7 according to the type of the medium and the thickness of the medium to warn the driver of the road condition.

6 is an electrical configuration of a road surface sensing apparatus according to a second embodiment of the present invention. In FIG. 6, parts that perform the same functions as those of FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 6, the road surface detection apparatus of the present invention is transmitted from an oscillator 10, a transmitter 11, an antenna 31 that emits a millimeter wave signal or collects a reflected signal. Circulator 32, a millimeter wave signal received from transmitter 11, and a circulator, which transmits a signal to the antenna 31 or sends a reflected millimeter wave signal received by the antenna 31 to the mixer 33. Receives and amplifies the intermediate frequency signal generated from the mixer 33 and the mixer 33 by mixing the reflected millimeter wave signal received from the radar 32 to generate an intermediate frequency signal such as a difference frequency or a sum frequency signal of the two signals. A / D converter 35 and A / D converter 35, which convert the signals amplified by the amplifying unit 34 and the amplifying unit 34 into digital signals, Street, adjacent In addition to the vehicle collision avoidance device configured to include a signal processor 36 for calculating a predetermined amount of adjacent vehicle information by arithmetic processing of the amount of speed and the like, the transmitting antenna 3 and the plurality of envelope detectors 13 described in FIG. 15, 20, receive antenna 4, splitter 12, multiple log-amps 14, 16, 21, switch 17, operator 18, inverse log-amp 19 It is made to include.

The bold signal lines in FIG. 6 represent millimeter wave transmission waveguides.

The main unit 2 displays the proximity vehicle information or accelerates or decelerates the warning unit 7, the throttle actuator 5, the brake actuator 6, etc. based on the received vehicle information, thereby preventing a vehicle collision. .

In addition, the main unit 8 calculates the type and thickness of the medium from the reflection coefficient of the medium, and controls the warning unit 7 from this information to inform the driver of the road surface condition.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea of the present invention.

According to the present invention as described above, compared to the conventional road surface detection device using the wheel speed sensor for each wheel, it is possible to determine the very accurate road surface state using millimeter wave, as well as to inform the road surface state information It works.

In addition, by sharing the existing oscillator and transmitter, economical efficiency, as well as the safety distance from the preceding vehicle, helps drivers to drive safely by warning the driver when road conditions are dangerous.

Claims (3)

In the road detection device for detecting a state of the road surface in the ongoing vehicle to issue a predetermined warning to the driver, A signal generator for generating millimeter waves; A radar sensor which emits a millimeter wave output from the signal generator on a road surface and receives a millimeter wave reflected by the road surface to calculate a reflection coefficient; A warning unit for outputting a road surface warning signal; And And a main unit for controlling the warning unit based on the information calculated by calculating the type and thickness of the medium based on the reflection coefficient calculated by the radar sensor. The method of claim 1, wherein the radar sensor An antenna for emitting a millimeter wave output from the signal generator and collecting a reflected signal; A signal generator for generating a millimeter wave and transmitting it to the antenna; A first envelope detector for detecting an envelope of the millimeter wave generated by the signal generator; A divider for separating and outputting the millimeter wave received through the antenna into P-polarized wave and S-polarized wave; A second envelope detector for detecting the envelope of the P-polarized wave distributed in the distributor; A third envelope detector for detecting an envelope of the S-polarized wave distributed in the distributor; A first log amplifier for log amplifying an output signal of the first envelope detector; A second log-amplifier for log amplifying an output signal of the second envelope detector; A third log amplifier for log amplifying the output signal of the third envelope detector; A switching unit for alternately outputting output signals of the second and third log-amps according to a predetermined control signal of the main unit; An operator for calculating an output signal output from the first log amplifier and two signals switched from the switching unit and outputting a corresponding output signal; And And an inverted log-amplifier for inverse log amplifying the output signal of the operator and outputting a reflection coefficient of the millimeter wave. The method of claim 1 or 2, wherein the signal generation unit A road surface characterized by firing a millimeter wave to the outside of the vehicle and acquiring obstacle information around the vehicle to control driving of the vehicle and sharing the signal as a signal source of the vehicle control device that alerts the presence of an obstacle. Sensing device.