JP2007304095A - Ultrasonic vehicle backing system and method for automatically correcting sensor scanning range - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for automatically correcting the sensor scanning range of a vehicle parking radar. <P>SOLUTION: The ultrasonic vehicle parking radar system automatically corrects the sensor scanning range and the method. The vehicle parking radar system comprises a central processing unit, which presets a compensation and a critical distance. When the vehicle parking radar is started, the surroundings status is recorded as an initial value. The initial value is compared with the following sensing distance as backing a vehicle. When the following distance is more than the total of the initial value and the compensation, the real distance between the blockade and ultrasonic sensors on the rear of the vehicle is compared with the critical distance. If the former is larger than the latter, the compensation is increased. When the blockade is more close the supersonic sensors, the sensitivity of ultrasonic sensors on both rear sides of the vehicle is reduced to avoid malfunction by the parking sensor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic vehicle retraction system and method, and more particularly to an ultrasonic vehicle retraction system and method for automatically correcting its sensor scan range.

  For safer and more convenient parking for the driver, a vehicle reverse radar is often attached to the vehicle to avoid accidents caused by rear obstacles. A general vehicle reverse radar uses an ultrasonic sensor that determines the presence or absence of an obstacle by transmitting an ultrasonic wave and detecting a reflected wave. When the ultrasonic wave encounters an obstacle, the ultrasonic wave is reflected and received by the ultrasonic sensor. At that time, the actual distance between the obstacle and the sensor is calculated using the velocity (340 m / s) information of the sound wave.

  Referring to FIG. 4, the normal ultrasonic sensor 32 transmits ultrasonic waves in a fan shape instead of a hemispherical shape. Therefore, the blind spot area 320 exists in the scanning area of the ultrasonic sensor 32. In order to minimize the blind area 32, the ultrasound emitted from the ultrasonic sensor 32 should be as hemispherical as possible, as shown in FIG. However, in that case, the scanning area may be too wide and other obstacles that are not immediately after the vehicle may be detected. At that time, the driver misunderstands and probably makes a wrong decision.

  In order to solve the aforementioned problems, some manufacturers have designed new ultrasonic sensors with a smaller outward scan area than before. Such sensors are arranged on the edges on both sides of the rear of the vehicle so as not to detect obstacles on both sides of the vehicle. In this case, it is necessary to install two different types of sensors in the vehicle. This method not only makes installation and maintenance difficult, but also increases the product price.

  Accordingly, it is an object of the present invention to provide a method for automatically correcting the sensor scan range of a vehicle reverse radar. The present invention adjusts the sensitivity of the sensors on both sides at the rear of the vehicle to solve the problem of malfunction of the prior art.

  In order to achieve the above object, main technical means apply the method to a central processing unit (CPU) of a vehicle reverse radar. The method includes the following steps, pre-determining correction values and one threshold threshold distance for several ultrasonic sensors, to detect obstacles when vehicle reverse radar is activated, Some ultrasonic sensors send out ultrasonic waves and obtain some initial sensing results, store initial sensing results as initial sensing values, ultrasonic sensors fail to obtain subsequent sensing results When the object is continuously detected, the subsequent sensing result is stored as a subsequent sensing value, and the subsequent sensing value of any of the ultrasonic sensors is greater than the corresponding “initial sensing value + correction value”, the obstacle is And detecting the actual distance between the obstacle and the ultrasonic sensor, and the actual distance between the ultrasonic sensor and the obstacle on both sides of the rear of the vehicle is a threshold distance (eg 60c ) When larger, comprising, to increase the correction value.

  The technical means described above can determine whether any obstacle is present within the threshold distance. By increasing the correction value, the situation for determining the presence of an obstacle increases, and thus the sensitivity of the ultrasonic sensor decreases. This achieves the goal of dynamically adjusting the sensitivity of the sensors on both sides of the rear of the vehicle. A malfunction of the vehicle reverse radar that detects an obstacle not immediately after the vehicle due to the excessively wide scanning range is prevented.

  Another object of the present invention is to provide a vehicle reverse radar that automatically corrects the sensor scan range. The vehicle reverse radar includes a CPU, a storage device, an ultrasonic transmission / reception module, a signal amplification module, and a warning module. The storage device is connected to the CPU. The ultrasonic transmission / reception module emits and receives ultrasonic waves. The ultrasonic transmission / reception module includes a plurality of sensor drivers and a plurality of ultrasonic sensors. The ultrasonic sensor is coupled to the CPU via the sensor driver. The CPU controls and drives the ultrasonic sensor to emit ultrasonic waves. The signal amplification module is connected between the CPU and the ultrasonic transmission / reception module to amplify the signal received by the ultrasonic sensor before sending it to the CPU. The warning module is connected to the CPU to notify the driver of any obstacles.

  A preferred embodiment of the present invention is illustrated in FIGS. The vehicle reverse radar disclosed herein includes a CPU 10, a storage device 20, an ultrasonic transmission / reception module 30, a signal amplification module 40, and a warning module 50.

  The CPU 10 is the central processing unit of the present invention. In this example, an ATMega8 microprocessor having a 1 kb memory was used.

  The storage device 20 is connected to the CPU 10 for storing digital data. In this embodiment, the storage device 20 is an internal memory of the ATMega8 microprocessor.

  The ultrasonic transmission / reception module 30 is used for radiation and reception of ultrasonic waves. As shown in FIG. 2A, the ultrasonic transmission / reception module 30 includes four sensor drivers 31, four ultrasonic sensors 321, 322, 323, and 324 and a multiplexer 33.

  Each sensor driver 31 includes transistors Q1 to Q4 and transformers T1 to T4. The bases of the transistors Q1-Q4 are connected to pins 13, 14, 16, 15 of the ATMega8 microprocessor, respectively. The pulse signal output from the CPU 10 is amplified by the transistors Q1 to Q4 and the transformers T1 to T4.

  The ultrasonic sensors 321, 322, 323, and 324 are connected to the CPU 10 via the sensor driver 31. In addition to using the pulse signals amplified by transistors Q1-Q4 and transformers T1-T4 to control and drive ultrasonic sensors 321, 322, 323, 324 to output ultrasonic waves, ultrasonic sensor 321 322, 323, 324 also receive ultrasound reflected by an obstacle that produces a reflected signal.

  The multiplexer 33 is connected to the pins 9 and 10 of the ATMega8 microprocessor and the sensor driver 31.

  The signal amplification module 40 is connected to the pin 24 of the ATMega8 microprocessor and the multiplexer 33 of the ultrasonic transmission / reception module 30. The reflected signals received by the ultrasonic sensors 321, 322, 323, and 324 are sent to the signal amplification module 40 for amplification through the switch of the multiplexer 33 before being sent to the CPU 10. In the present embodiment, as shown in FIG. 2C, the signal amplification module 40 mainly includes three operational amplifiers (op-amps) U1C, U1D, and U1A. The amplifier U1C amplifies the reflected signals received by the ultrasonic sensors 321, 322, 323, and 324, and sends them to a bandpass filter for noise removal, which includes the amplifier U1D, a resistor R5, and a capacitor C8. . The reflected signal is further amplified by the amplifier U1A, rectified by the diode D3, and finally sent to the CPU 10.

  The warning module 50 is connected to the CPU 10 to notify the driver of any obstacles. As shown in FIGS. 1 and 2, the warning module 50 of this embodiment includes a display device 511 and an acoustic warning device. The display device 511 is connected to the pins 30 and 31 of the ATMega8 microprocessor via the drive circuit 521. The acoustic warning device is a buzzer connected to pins 1 and 12 of the ATMega8 microprocessor via an acoustic drive circuit 521.

  The method of automatically correcting the sensor scanning range of the vehicle backward radar disclosed here is applied to the CPU 10 described above. Its operating principle is based on the fact that the ultrasonic energy reflected by the obstacle is proportional to the size of the obstacle. The larger the obstacle, the more it reflects more ultrasonic energy. With reference to FIGS. 3A and 3B, the method includes the following steps.

  First, four correction values and threshold distances are predetermined (step 100). Each correction value corresponds to one of the ultrasonic sensors 321, 322, 323, and 324. The threshold distance is set to 60 cm according to a preferred embodiment of the present invention.

  After the vehicle reverse radar is activated, each ultrasonic sensor 321, 322, 323, 324 immediately transmits an ultrasonic wave for detecting an obstacle (step 101).

  Each ultrasonic sensor 321, 322, 323, 324 receives the ultrasonic wave reflected by the obstacle to obtain an initial sensing result corresponding to the respective ultrasonic sensor 321, 322, 323, 324 (step 102). .

  The CPU 10 converts the initial sensing results into initial sensing values and stores them in the storage device 20 (step 103).

  Each of the ultrasonic sensors 321, 322, 323, and 324 continues to transmit an ultrasonic wave for detecting an obstacle and continuously receives an ultrasonic wave reflected from the obstacle. Accordingly, a plurality of subsequent sensing results of the ultrasonic sensors 321, 322, 323, and 324 are obtained (step 104).

  The CPU 10 converts the subsequent sensing results into subsequent sensing values and stores them in the storage device 20 (step 20).

  Thereafter, the subsequent sensed values of the ultrasonic sensors 321, 322, 323, 324 are “initial sensed value + correction” to determine which subsequent sensed value is greater than the sum of the initial sensed value and the corresponding correction value. Compared with "value". If not, the radar determines that there are no obstacles in range (step 107). If so, then the radar determines that an obstacle has been detected within range (step 108).

  Further, when an obstacle is detected, the actual distance between the obstacle and the ultrasonic sensors 321, 322, 323, 324 is calculated based on the speed of sound (340 m / sec), the transmission of ultrasonic waves and the reflected ultrasonic waves. It is calculated using the time interval between receptions (step 109).

  The calculated actual distance between the obstacle and the ultrasonic sensors on both sides of the rear of the vehicle is compared with the threshold distance (step 110). If the latter is larger than the former, then the CPU 10 drives the warning module 50 to issue a warning to the driver (step 111). Otherwise, the correction value is increased (step 112), so that the total value of “initial sense value + correction value” is increased. Therefore, in order to be larger than “initial sense value + correction value”, a larger subsequent sense value is required. That is, the size of the obstacle needs to be larger or it must be closer to the vehicle. Therefore, it can be considered that the sensitivity of the ultrasonic sensors 321, 322, 323, and 324 decreases.

  The operating principle of the individually disclosed vehicle reverse radar is explained as follows.

  Before the vehicle moves backwards, the vehicle will be at a great distance from any obstacle. Thus, less ultrasound is reflected by the obstacle, resulting in a smaller initial sense value.

  As the vehicle moves backwards, the distance to the obstacle will be less. As the solid angle to the rear of both vehicles determined by the obstacle increases, more ultrasonic waves are reflected. Thus, the subsequent sense value will be greater than the initial sense value recorded before the vehicle retreated. Possible errors are avoided by requiring that the subsequent sensed value be greater than the sum of the initial sensed value and the correction value.

  When the actual distance between the obstacle and the ultrasonic sensors on both sides is greater than the threshold distance, it means that the obstacle may be outside the rear of the vehicle. In this case, the sensitivity of the vehicle reverse radar can be decreased by increasing the correction value, and as a result, inaccurate operation can be prevented.

  In summary, the vehicle reverse radar disclosed herein records the initial ambient conditions before the vehicle reverses. Next, in order to determine whether or not an obstacle is present while the vehicle is moving backward, the initial ambient situation is compared with the ambient situation. If it is determined that there are no nearby obstacles on either side of the rear of the vehicle, the present invention automatically corrects the scanning range of the ultrasonic sensors on both sides of the rear of the vehicle to reduce sensitivity. This prevents the driver from making mistakes due to the malfunction of the vehicle reverse radar.

It is a block diagram of the vehicle backward radar which concerns on this invention. FIG. 3 is a circuit diagram (No. 1) of the vehicle reverse radar according to the present invention. FIG. 3 is a circuit diagram (No. 2) of the vehicle reverse radar according to the present invention. FIG. 4 is a circuit diagram (No. 3) of the vehicle reverse radar according to the present invention. FIG. 6 is a circuit diagram (No. 4) of the vehicle reverse radar according to the present invention. FIG. 6 is a circuit diagram (No. 5) of the vehicle reverse radar according to the present invention. It is a flowchart (the 1) of the method which concerns on this invention. It is a flowchart (the 2) of the method which concerns on this invention. It is the schematic of the scanning range (the 1) of the ultrasonic sensor of the conventional vehicle backward radar. It is the schematic of the scanning range (the 2) of the ultrasonic sensor of the conventional vehicle backward radar.

Explanation of symbols

10 CPU (Central Processing Unit)
DESCRIPTION OF SYMBOLS 20 Memory | storage device 30 Ultrasonic wave transmission / reception module 31 Sensor driver 32,321,322,323,324 Ultrasonic sensor 320 Blind spot area 33 Multiplexer 40 Signal amplification module 50 Warning module 511 Display apparatus 512 Display driver 521 Acoustic drive circuit 522 Acoustic warning apparatus

Claims (6)

Predetermining correction values and a threshold distance for a plurality of ultrasonic sensors;
When the vehicle reverse radar is activated, it sends out ultrasonic waves from the ultrasonic sensor to detect any obstacles, and obtains respective initial sensing results from the ultrasonic sensor;
Storing each of the initial sensing results as an initial sensing value;
Continuously detecting obstacles using the ultrasonic sensor to obtain multiple subsequent sensing results from the ultrasonic sensor;
Storing each subsequent sensing result as a subsequent sensing value;
When the subsequent sensing value of any of the ultrasonic sensors is greater than the corresponding “initial sensing value + correction value”, it is determined that an obstacle has been detected, and the actual distance between the obstacle and the ultrasonic sensor is determined. Calculating,
When the actual distance between one of the ultrasonic sensors mounted on both sides of the rear part of the vehicle as a corner ultrasonic sensor and the obstacle is larger than the threshold distance, the sensitivity of the corresponding corner ultrasonic sensor Automatically reducing the ultrasonic sensor scan range of the vehicle reverse radar, including increasing the correction value of the corresponding corner ultrasonic sensor that detects that the actual distance is greater than the threshold distance. How to fix. An ultrasonic vehicle retraction system using the method of claim 1 for automatically correcting a sensor scan range comprising:
CPU (10),
A storage device (20) connected to the CPU (10);
An ultrasonic transmission / reception module (30) used for emitting ultrasonic waves and receiving ultrasonic waves, comprising a plurality of sensor drivers (31) and ultrasonic sensors (321-324), the ultrasonic sensor An ultrasonic transmission / reception module (30), each of which is coupled to the CPU (10) via each sensor driver (31) and controlled to emit ultrasonic waves by the CPU (10). ,
Connected between the CPU (10) and the ultrasonic transceiver module (30) to amplify radio waves received by the ultrasonic sensors (321-324) and then send them to the CPU (10) A signal amplification module (40) to be operated;
A warning module (50) connected to the CPU (10) for notifying the driver of the obstacle;
The storage device (20) stores a correction value and one threshold distance for the ultrasonic sensor (321-324), and when the vehicle reverse radar is activated, the ultrasonic sensor (321-324). Transmits an ultrasonic wave in order to detect any obstacle and obtain an initial sensing result, and the storage device (20) stores each initial sensing result as an initial sensing value, and then The sonic sensor (321-324) continuously detects an obstacle to obtain a subsequent sensing result, and the storage device (20) stores each subsequent sensing result as a subsequent sensing value, and When the subsequent sensing value of the acoustic wave sensor (321-324) is larger than the corresponding “initial sensing value + correction value”, it means that an obstacle has been detected, and the CPU (10) When the actual distance between the ultrasonic sensor mounted on both sides at the rear of the vehicle is larger than the threshold distance, the actual distance is calculated as follows: An ultrasonic vehicle retraction system, wherein the correction value of a corresponding ultrasonic sensor mounted on one side at the rear of the vehicle that detects greater than the threshold distance is increased to reduce sensitivity.   The ultrasonic transmission / reception module (30) further includes a multiplexer (33) connected to the CPU (10), the sensor driver (31), and the signal amplification module (40). The multiplexer (33) is for amplification. The ultrasonic vehicle retraction system according to claim 3, wherein a signal is selected to be sent to the signal amplification module (40). The warning module (50) includes a display device (511) connected to the CPU (10) via a display driver (512),
The ultrasonic vehicle retraction system according to claim 3, comprising an acoustic warning device (522) which is a buzzer connected to the CPU (10) via an acoustic drive circuit (521).   The ultrasonic vehicle retraction system according to claim 3, 4 or 5, wherein the storage device (20) is incorporated in the CPU (10).   The ultrasonic vehicle retraction system according to claim 6, wherein the CPU (10) is an ATMega8 microprocessor.

Images