JP3101106B2 - Automotive ultrasonic detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-vehicle ultrasonic detector which detects an obstacle or a human body by using ultrasonic waves and provides a safe driving to a driver.

[0002]

2. Description of the Related Art An in-vehicle ultrasonic detector using ultrasonic waves performs sensing using ultrasonic waves, intermittently transmits ultrasonic pulse signals, and detects obstacles or human bodies existing in the vicinity. By receiving a reflected wave from the vehicle, an obstacle or a human body is detected, the driver is informed of danger, and safe driving is provided.

[0003] The configuration of a conventional on-vehicle ultrasonic detector is shown in FIG.
As shown in, by arranging a plurality of ultrasonic detectors 1 (1 ₁ to 1 ₄₎ to the body of the bumper portion of the corner portion in the vicinity of the vehicle, to monitor the surrounding obstacles, the operation A main body circuit 2 to be controlled is mounted in a vehicle room or a trunk room, and a display unit 3 is mounted near a driver in the vehicle room.

FIG. 6 shows a detection area of the ultrasonic detector 1, and FIG. 6A shows a detection area on a horizontal plane.
(B) shows the detection area on the vertical plane. FIG. 7 shows a conventional circuit configuration, and FIG.
The waveform of each part at point d is shown. 7, main body circuit 2 each of the ultrasonic detectors 1 ₁ to 1 ₄ comparator 4 corresponds to each channel to have a detection circuit 5, the output of the detection circuit 5 is input R ₁ of the CPU 7 ~ is input to the R _4.

Further, a signal is sent to the display unit 3 at the output of the CPU 7, to display at the LED display unit 8 by the light emitting diode corresponding to the ultrasonic detector ₁ 1 to 1 _4, also broadcast by the buzzer 9 It is supposed to do. Further, a power supply circuit 6 for supplying power to each unit is provided. Next, the operation of the conventional configuration will be described with reference to FIGS. A plurality of vehicles provided at corners around the vehicle, in this example four
Numbers of ultrasonic detectors 1 ₁ to 1 ₄ are controlled by the main body circuit 2, transmitting signals from CPU7 of the body circuit 2 (FIG. 8
(See (a))).

After receiving and amplifying a reflected wave from an obstacle or a human body (see FIG. 8B), the comparator 4 shapes the waveform into a pulse waveform (see FIG. 8C). (See FIG. 8 (d)), and then the CPU
7 is input. As shown in the processing flowchart of FIG. 9, the CPU 7 counts the time T ₁ (see FIG. 8D) from the output of the ultrasonic pulse to the input of the reflected wave pulse. Then, it calculates the distance from the count value T ₁ to the obstacle, the display unit 3 when the distance is within a predetermined range
To perform display output.

[0007] The distance L to the obstacle, when the speed of sound is c, obtained with _{L = c · T 1/2} (m). Display unit 3 is connected to the main body circuit 2, in which the alarm display by a plurality of ultrasonic detectors 1 ₁ to 1 emitting diode and a buzzer sound of the buzzer 9 of the LED display unit 8 corresponding to the site of ₄ .

Here, the main body circuit 2 is supplied with power from a vehicle via a power supply circuit 6, and is connected to a vehicle speed signal input and a back signal input to control the entire operation. The display output is performed when the vehicle speed becomes equal to or lower than a predetermined speed by an input, and the display output is controlled to be prohibited when the vehicle speed becomes equal to or higher than the predetermined speed.

Further, so as to control the operation of the ultrasonic disposed rearwardly detector 1 _3, 1 ₄ by back signal input.

[0010]

However, in such a conventional example, it is necessary to connect a vehicle speed signal and a back signal, and there is a problem that a moving direction and a moving distance cannot be calculated. The present invention is provided in view of the above points, does not require connection of a vehicle speed signal or a back signal, and performs operation control of an ultrasonic detector according to a traveling state of a vehicle, and also includes a moving distance The present invention provides a vehicle-mounted ultrasonic detector for calculating a moving direction and displaying a moving distance and a moving direction.

[0011]

According to the present invention, an obstacle is detected around a vehicle by arranging a plurality of ultrasonic detectors around the vehicle, transmitting an ultrasonic pulse signal and receiving a reflected signal from an object. Then, in an in-vehicle ultrasonic detector that displays a danger warning to the driver, a detection unit that detects a Doppler component of a reflected signal from an object or a road surface, and calculates a vehicle speed from the Doppler component detected by the detection unit Vehicle speed calculating means;
When the vehicle speed calculated by the vehicle speed calculation means is equal to or lower than a predetermined vehicle speed, an alarm is displayed to the driver, and when the vehicle speed is equal to or higher than the predetermined vehicle speed, the alarm display to the driver is stopped. Calculate the moving distance and moving direction of the car,
Control means for displaying a moving distance and a moving direction.

According to a second aspect of the present invention, there is provided a correcting means for calculating a moving distance and a moving direction based on a vehicle speed detected by a plurality of ultrasonic detectors arranged around the vehicle, and correcting position information of the vehicle. . Further, in claim 3, a display means is provided for displaying the forward and backward speeds based on the vehicle speed detected by a plurality of ultrasonic detectors arranged around the vehicle.

[0013]

According to the present invention, the connection of the vehicle speed signal and the back signal is unnecessary, the operation of the ultrasonic detector is controlled according to the running state of the vehicle, and the moving distance and the moving direction are calculated. The moving distance and moving direction can be displayed. Therefore, a safe sensor operation can always be obtained.

According to a second aspect of the present invention, there is provided a correcting means for calculating a moving distance and a moving direction on the basis of vehicle speeds detected by a plurality of ultrasonic detectors arranged around the vehicle and correcting positional information of the vehicle. Thus, a vehicle speed value superior in accuracy can be obtained as compared with a vehicle speed signal obtained from rotation of the axle.
Therefore, it is possible to control the operation of the ultrasonic detector according to the running state of the vehicle, and to always obtain a safe sensor operation. In addition, a plurality of ultrasonic detectors arranged around the vehicle can determine whether the vehicle is moving forward or backward, and can correct errors due to steering angle, vehicle slip, etc. High detection can be performed.

Further, according to the present invention, a display means for displaying the speed at the time of forward movement and the speed at the time of reverse movement based on the vehicle speed detected by a plurality of ultrasonic detectors arranged around the vehicle is provided. It is also possible to display the vehicle speed at the time of forward travel as well as at the time of reverse travel from the Doppler component, thereby contributing to the safe driving of the driver.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. With in the present invention by transmitting an ultrasonic pulse and receiving the reflected waves from the obstacle and the human body, from the time count value T ₁ of the up reflected wave pulse input, calculates the distance to the obstacle, the object And a Doppler component of the reflected signal from the road surface and the like, and a vehicle speed, a moving distance, and a moving direction are calculated from the detected Doppler component.

When the vehicle speed is lower than a predetermined vehicle speed, an alarm is displayed to the driver when an obstacle or an object approaches, and when the calculated vehicle speed is higher than the predetermined vehicle speed, the driver is warned. The display of the moving distance and the moving direction are displayed while the warning display is stopped. Here, assuming that the frequency of the transmitted ultrasonic pulse wave is f ₀ , the sound speed is sound speed c, and the vehicle speed is V, by the Doppler effect,
Since the frequency fr of the received reflected wave is fr = f ₀ · (c + V) / c, the sound velocity V is: V = c · (fr−f ₀ ) / f ₀ (km / h) The moving distance L is L = ∫Vdt (km).

[0018] In an embodiment of the present invention, instead of the frequency, which has to calculate the vehicle speed by measuring the wavelength of the reflected wave, wherein is calculated by 10 wavelengths of time T _2. That is, V = c · {(10 / T ₂ ) −f ₀ ) / f ₀ } (km
/ H).

FIG. 2 is a circuit diagram of the entire circuit, and FIGS. 3 and 4 show waveforms of respective parts. Note that the ultrasonic detector 1, the main body circuit 2, the display unit 3 and the like are the same as the conventional one, and in this embodiment, a counter 10 is newly added to the main body circuit 2,
The speed, distance, and the like calculated by the CPU 7 are displayed on the speed display unit 11 and the distance display unit 12. A detecting means for detecting a Doppler component of a reflected signal from an object or a road surface; a vehicle speed calculating means for calculating a vehicle speed from the Doppler component detected by the detecting means; and a vehicle speed calculated by the vehicle speed calculating means being equal to or less than a predetermined vehicle speed. When the vehicle speed is equal to or higher than a predetermined vehicle speed, the warning display to the driver is stopped, and the moving distance and the moving direction of the vehicle are calculated from the Doppler component. The control means for displaying the moving direction is constituted by the CPU 7.

Next, the operation will be described. FIG. 3 (a)
4 (e) show the waveforms at points a to e in FIG. 2, and FIG. 4 is an enlarged waveform diagram of the X portion in FIGS. 3 (c) to 3 (e). A plurality of ultrasonic detectors 1 ₁ to 1 ₄ provided on the corner portion of the peripheral vehicle is controlled by the main circuit 2, the ultrasonic pulse by transmitting a signal from the body circuit 2 (see FIG. 3 (a)) , And receives and amplifies reflected waves from obstacles and the human body (see FIG. 3B).

The output is shaped into a pulse waveform by the comparator 4 of the main circuit 2 (see FIG. 3 (c)).
While that is input to the input terminal R ₁ to R ₄ of U7, pulse waveform (FIG. 3 (c) refer) to after counting 10 wavelengths (Fig. 3
(See (e)), and are input to the input terminals C _{1 to} C ₄ of the CPU 7. In the CPU 7, as the processing flow chart shown in FIG. 1, after the output ultrasonic pulse, (see FIG. 3 (c)) after counting the time T ₁ of the up after reflection wave pulse input,
As shown in FIG. 4, counts the T ₂ 10 wavelengths of time.

If the vehicle speed V calculated from the count value T ₂ is equal to or less than 10 km / h, an alarm display such as an obstacle or a human body is displayed in accordance with the time count value T ₁ until the reflected wave pulse is input. If the speed is 10 km / h or more, the display output is forcibly turned off, and the moving distance, the moving direction, and the like are calculated and displayed from the vehicle speed.

[0023] Here, we describe the detection principle of one channel of the sensor cis, 5 and 6, a plurality of ultrasonic detectors 1 ₁ to 1 ₄ around the vehicle
By using the respective detection results, it is possible to correct an error due to a steering wheel turning angle, a vehicle slip, or the like, and to perform highly accurate detection.

Here, the calculated vehicle speed can be displayed, and the vehicle speed can be displayed not only at the time of forward running but also at the time of reverse running from the Doppler component.
The speed at the time of forward movement, at the time of reverse movement, etc. is displayed on the speed display section 11 composed of a light emitting diode or the like. The moving distance is displayed by a distance display unit 12 composed of a light emitting diode or the like.

[0025]

As described above, the present invention detects obstacles around a vehicle by arranging a plurality of ultrasonic detectors around a vehicle, transmitting an ultrasonic pulse signal and receiving a reflected signal from an object. Then, in an in-vehicle ultrasonic detector that displays a danger warning to the driver, a detection unit that detects a Doppler component of a reflected signal from an object or a road surface, and calculates a vehicle speed from the Doppler component detected by the detection unit A vehicle speed calculating means for displaying an alarm to the driver when the vehicle speed calculated by the vehicle speed calculating means is equal to or lower than a predetermined vehicle speed, and stopping an alarm display to the driver when the vehicle speed is equal to or higher than the predetermined vehicle speed; And a control means for calculating the moving distance and the moving direction of the vehicle from the Doppler component and displaying the moving distance and the moving direction. Therefore, connection of the vehicle speed signal and the back signal is unnecessary,
In addition to controlling the operation of the ultrasonic detector according to the running state of the vehicle, the moving distance and the moving direction can be calculated, and the moving distance and the moving direction can be displayed. Therefore, there is an effect that a safe sensor operation can always be obtained.

According to a second aspect of the present invention, there is provided a correcting means for calculating a moving distance and a moving direction based on vehicle speeds detected by a plurality of ultrasonic detectors arranged around the vehicle and correcting positional information of the vehicle. Thus, a vehicle speed value superior in accuracy can be obtained as compared with a vehicle speed signal obtained from rotation of the axle.
Therefore, it is possible to control the operation of the ultrasonic detector according to the running state of the vehicle, and to always obtain a safe sensor operation. In addition, a plurality of ultrasonic detectors arranged around the vehicle can determine whether the vehicle is moving forward or backward, and can correct errors due to steering angle, vehicle slip, etc. High detection can be performed.

Further, according to the present invention, a display means for displaying the speed at the time of forward movement and the speed at the time of reverse movement based on the vehicle speed detected by a plurality of ultrasonic detectors arranged around the vehicle is provided. It is also possible to display the vehicle speed at the time of forward travel as well as at the time of reverse travel from the Doppler component, thereby contributing to the safe driving of the driver.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a processing flowchart of a CPU according to an embodiment of the present invention.

FIG. 2 is an overall circuit configuration diagram of the vehicle mounted ultrasonic detector.

FIG. 3 is an operation waveform diagram of the main body circuit according to the first embodiment;

FIG. 4 is an enlarged waveform diagram of a main part of FIG. 3 of the above.

FIG. 5 is a diagram showing the arrangement of the above system.

FIG. 6 is a diagram showing a detection area according to the embodiment.

FIG. 7 is an overall circuit configuration diagram of a conventional on-vehicle ultrasonic detector.

FIG. 8 is an operation waveform diagram of a conventional example.

FIG. 9 is a diagram showing a processing flowchart of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic detector 2 Main body circuit 3 Display part 4 Comparator 5 Detection circuit 7 CPU 10 Counter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-172943 (JP, A) JP-A-1-101488 (JP, A) JP-A-63-207883 (JP, A) 148487 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S ⁷ /52-7/64 G01S 15/00-15/96

Claims (3)

(57) [Claims] 1. A plurality of ultrasonic detectors are arranged around a vehicle, an ultrasonic pulse signal is transmitted, and a reflected signal from an object is received to detect an obstacle around the vehicle, thereby alerting the driver of danger. In an on-vehicle ultrasonic detector for displaying, a detecting means for detecting a Doppler component of a reflected signal from an object or a road surface, a vehicle speed calculating means for calculating a vehicle speed from the Doppler component detected by the detecting means, When the vehicle speed calculated by the means is equal to or lower than a predetermined vehicle speed, an alarm is displayed to the driver, and when the vehicle speed is higher than the predetermined vehicle speed, the alarm display to the driver is stopped. A vehicle-mounted ultrasonic detector comprising: a control unit that calculates a distance and a moving direction and displays the moving distance and the moving direction. 2. A moving distance and a moving direction are calculated based on vehicle speeds detected by a plurality of ultrasonic detectors arranged around the vehicle.
The on-vehicle ultrasonic detector according to claim 1, further comprising a correction unit configured to correct the position information of the vehicle. 3. An in-vehicle vehicle according to claim 1, further comprising display means for displaying speeds when the vehicle is moving forward and when the vehicle is moving backward based on vehicle speeds detected by a plurality of ultrasonic detectors arranged around the vehicle. Sound wave detector.