KR20010056696A - Device and method for measuring distance using ultrasonic waves - Google Patents

Abstract

PURPOSE: An improved supersonic wave distance measuring apparatus and a method thereof are provided to reduce the unnecessary alarm by controlling amplification rate of an amplifier and a reference signal of a comparator according to the change of the height and noise of a vehicle. CONSTITUTION: An improved supersonic wave distance measuring apparatus includes a CPU(10) controlling the whole system elements of the supersonic wave measuring apparatus and operating the distance, a supersonic wave driving circuit(20) driving a transmission signal outputted from the CPU, a height sensor(30) attached to a bumper for measuring the height of a vehicle, a supersonic wave transmitting sensor part(40) emitting supersonic waves by the driving of the supersonic wave driving circuit, a supersonic wave receiving sensor part(50) receiving supersonic wave signal emitted from the supersonic transmitting sensor part and reflected, a band pass filter(60) passing only driving pulse frequency in the received supersonic waves, a variable amplifying circuit(70) variably adjusting the amplification rate of the band-passed supersonic signal by the control of the CPU, a detection circuit(80) detecting the signal amplified by the variable amplification circuit, a comparator(90) comparing the output signal of the detection circuit with a linear reference signal stored in the comparator for converting the comparison result to the digital signal, and a distance display and alarm device(100) receiving distance and alarm signal operated in the CPU for displaying the distance and generating alarm.

Description

DEVICE AND METHOD FOR MEASURING DISTANCE USING ULTRASONIC WAVES}

The present invention relates to an improved ultrasonic distance measuring apparatus and method, and more particularly, to amplify a sensor according to a change in height of a vehicle by using a garage sensor to reduce the occurrence of false alarms due to noise and the like which a conventional distance measuring apparatus has. And an improved ultrasonic distance measuring apparatus and method for reducing the occurrence of false alarms by controlling a reference signal value.

In the conventional distance measuring apparatus using an ultrasonic sensor, when the transmitting sensor unit emits ultrasonic waves by receiving the transmission signal from the central processing unit, the ultrasonic receiving sensor unit receives the received ultrasonic waves by reflecting the reflected ultrasonic signals to a predetermined object and receiving the received ultrasonic waves. It passes the desired frequency band in the signal and amplifies it. After the detection, the CPU receives the comparison result compared with the reference signal, calculates the distance, and operates the display device. However, this distance measuring device has a problem in that the sensitivity is significantly reduced since the temperature and frequency characteristics of the sensor are not considered. To this end, a sensor has been developed to improve the temperature and frequency characteristics of the ultrasonic sensor. Although there is no need to alarm when passing through such severe climbing roads, false alarms are often issued by echo signals and noise signals.

Accordingly, the present invention was developed under the above-described background, and provides an improved ultrasonic distance measuring apparatus and method for reducing the occurrence of false alarms by controlling the amplification rate and the reference signal value of the sensor according to the height change of the vehicle using the height sensor. The purpose.

1 is a block diagram of an improved ultrasonic measuring apparatus of the present invention,

2 is a flowchart showing an improved ultrasonic measuring method of the present invention;

3a, b and c show signal waveforms reflected by gravel, a large wall and a general target, respectively;

<Explanation of symbols for the main parts of the drawings>

10: central processing unit 20: ultrasonic drive circuit

30: garage sensor 40: ultrasonic transmission sensor unit

50: ultrasonic receiving sensor 60: band filter

70: variable amplifier circuit 80: detection circuit

90: comparator 100: distance indicator and alarm

The improved ultrasonic distance measuring apparatus of the present invention for achieving the above object, controls the whole system element of the ultrasonic distance measuring device, and performs a calculation of the distance, driving the transmission signal output from the central processing device Ultrasonic drive circuit to the ultrasonic wave, Ultrasonic transmission sensor unit for radiating the ultrasonic wave by the drive of the ultrasonic drive circuit, Garage sensor for measuring the height of the vehicle, Ultrasonic signal reflected by the ultrasonic wave emitted from the ultrasonic transmission sensor unit to a predetermined object reflected Ultrasonic receiving sensor unit for receiving a band filter for passing only the driving pulse frequency in the ultrasonic wave received by the ultrasonic receiving sensor unit, Variable amplification to adjust the amplification rate under the control of the centralized processing unit for the band-passed ultrasonic signal A detection circuit for detecting a signal amplified by the circuit and the variable amplifier circuit, the detection circuit The comparator compares the circuit output signal with a linear reference signal of its own storage and converts the result of the comparison into a digital value. The comparator outputs the distance and the alarm signal calculated by the central processing unit. It is characterized by comprising a distance display and an alarm device.

In addition, the improved ultrasonic distance measuring method of the present invention includes a variable initialization step of initializing a system variable in an initial state, a sensor and a system diagnosis for checking an abnormality of a sensor and a system by measuring a ringing time of a received signal. Step, if it is confirmed that there is no abnormality of the sensor and the system in the sensor and system diagnostic step, the distance to transmit and receive the ultrasonic wave by the transmission and reception ultrasonic sensor to measure the distance to a predetermined object and the height of the vehicle by the garage sensor And a height measurement step, a variable amplification rate control and signal filtering step of controlling the amplification rate according to the state of the received signal and the height of the vehicle and performing software filtering, and calculating the difference between the transmission and reception time to convert the measured time data into the distance data. According to the distance calculation step and the distance data calculated in the distance calculation step D) a distance display and an alarm step of outputting a distance display and an alarm signal to the distance display and alarm device.

Hereinafter, with reference to the accompanying drawings, an improved ultrasonic distance measuring apparatus and method of the present invention will be described in detail.

1 is a block diagram of an improved ultrasonic measuring apparatus of the present invention.

Referring to the operation of each component in the figure, the central processing unit 10 controls the entire system element of the ultrasonic distance measuring device, and performs the calculation of the distance. The ultrasonic driving circuit 20 drives the transmission signal output from the central processing unit 10. The garage sensor 30 is attached to the bumper to measure the height of the vehicle. The ultrasonic transmission sensor unit 40 emits ultrasonic waves by the driving of the ultrasonic driving circuit 20. The ultrasonic reception sensor unit 50 receives the ultrasonic signal radiated from the ultrasonic transmission sensor unit 40 to fit a predetermined object and reflected. The band pass filter 60 passes only the driving pulse frequency in the ultrasonic wave received by the ultrasonic wave receiving sensor unit. The variable amplification circuit 70 is controlled by the central processing unit 10 receives the band pass ultrasonic signal to variably adjust its amplification rate. The detection circuit 80 detects the signal amplified by the variable amplification circuit 70, and the comparator 90 compares the output signal of the detection circuit 80 with a linear reference signal of its own storage and compares the result of the comparison. Convert to digital value and output. And the distance display and alarm device 100 receives the distance and the alarm signal calculated by the central processing unit by the output of the comparator 90 to display the distance and alarm.

According to the operation of the configuration, when the ultrasonic driving circuit 20 drives the ultrasonic waves in response to the transmission signal of the central processing unit 10, the ultrasonic transmission sensor unit 40 radiates the ultrasonic waves, which are the ultrasonic wave And reflected on the received by the ultrasonic receiving sensor unit 50. Then, the received ultrasonic signal passes only the driving pulse frequency through the band filter BPF. The ultrasonic signal passing through the band pass filter 60 is variably amplified by the variable amplification circuit 70. That is, under the control of the central processing unit 10, the variable amplification circuit 70 reduces the amplification rate in the noisy areas such as gravel roads, and restores the amplification rate in the noisy areas. In addition, by measuring the height of the vehicle from the height sensor 30 increases the amplification rate when the height of the vehicle is high, and decreases the amplification rate when the height of the vehicle is low. Normally, the height of the vehicle is determined by the road surface state or the total load of the vehicle. For example, if a vehicle has a large number of passengers, the height of the vehicle is lowered and vice versa. The variable amplified signal is detected by the detection circuit 80 and output to the comparator 90. In the comparator 90, the signal detected by the detection circuit 80 and its own linear reference signal are compared, and the comparison result is converted into a digital value and output. The output signal of the comparator calculates the distance by the central processing unit 10 and outputs it to the distance display and alarm device to generate the distance display and alarm.

3A, 3B, and 3C show signal waveforms reflected by gravel, a large wall, and a general target, respectively, and signals and noise caused by gravel shown in FIG. 3A have very irregular reception waveforms. Therefore, if the signal caused by the gravel noise is detected, software filtering reduces the occurrence of false alarms. That is, the ultrasonic transmission sensor unit 40 having 2-4 sensors emits a signal two or three times, and when the same signal comes in as many times as the number of radiation, it is determined to be a normal target.

In addition, as shown in FIG. 3B, when there is a large wall outside the measurement section, when a transmission / reception period is 24 msec, it is difficult to distinguish between a target of a close distance or a large wall outside the measurement section. By varying the transmission / reception period, that is, about 30 msec, it is possible to distinguish whether the target is a real target or an echo.

On the other hand, the reference signal of the comparator 90, the central processing unit 90 controls the reference signal value in time division according to the change of the distance of the target and the height of the vehicle to reduce the occurrence of unnecessary alarm.

FIG. 2 shows a flowchart illustrating an improved ultrasonic measurement method of the present invention, with reference to the figures and FIG. 1 to describe the method of the present invention.

First, the central processing unit 10 initializes the system variables in the initial state (S10), and measures the reverberation time (ringing time) of the received signal to check whether there is an abnormality of the sensor and the system (S20). The reverberation sound measurement is performed in the self-diagnosis mode. If there is reverberation, the system is normal. If there is no reverberation, the system is abnormal. When it is confirmed that there is no abnormality of the sensor and the system in the sensor and system diagnostic step, the ultrasonic wave is transmitted and received by the transmitting and receiving ultrasonic sensors 40 and 50 to measure a distance to a predetermined object, and to the garage sensor 30. The height of the vehicle is measured (S30). Subsequently, the CPU 10 controls the amplification factor according to the state of the received signal and the height of the vehicle and performs software filtering (S40). The distance between the transmission and reception time is calculated and distance data is calculated as distance data (S50), and the distance display and alarm signal are output to the distance display and alarm device 100 according to the calculated distance data (S60). ). This can reduce the occurrence of false alarms due to measurement errors caused by noise or the like.

According to the apparatus and method of the present invention as described above, in the distance measuring device using an ultrasonic sensor, by controlling the amplification ratio of the amplifier and the reference signal value of the comparator in the central processing unit according to the change of the height and noise of the vehicle, A significant effect of reducing the occurrence can be obtained.

Claims (2)

A central processing unit that controls all the system elements of the ultrasonic distance measuring device, performs a calculation of the distance, an ultrasonic driving circuit for driving the transmission signal output from the central processing unit, and the ultrasonic wave by the driving of the ultrasonic driving circuit An ultrasonic transmission sensor unit, a height sensor for measuring a height of a vehicle, an ultrasonic reception sensor unit for receiving ultrasonic signals reflected and reflected by ultrasonic waves emitted from the ultrasonic transmission sensor unit, and received by the ultrasonic reception sensor unit A band pass filter for passing only a driving pulse frequency in an ultrasonic wave, a variable amplification circuit for adjusting the amplification factor under the control of the central processing unit, and a detection circuit for detecting a signal amplified by the variable amplification circuit; The detection circuit output signal is compared with a linear reference signal of self storage And a distance display and an alarm for receiving a distance and an alarm signal calculated by the central processing unit by the output of the comparator and outputting the digital value to the digital value. Device. Variable initialization step of initializing the system variable in the initial state, sensor and system diagnostic step to check the abnormality of the sensor and system by measuring the ringing time (ringing time) of the received signal, sensor and system in the sensor and system diagnostic step If it is confirmed that there is no abnormality, the distance and height measurement step of measuring the distance to a predetermined object by transmitting and receiving the ultrasonic wave by the transmission and reception ultrasonic sensor and the height of the vehicle by the height sensor, the state of the received signal and the vehicle A variable amplification factor control and signal filtering step of controlling the amplification factor according to the height of the signal and performing software filtering, a distance calculation step of converting the measured time data into distance data by calculating the difference between the transmission and reception times, and the distance calculation step Distance display and alarm signal according to distance data and alarm Distance measurement method using the ultrasonic sensor comprising a distance display and alarm outputting a.