JP3044813B2 - Ultrasonic sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic sensor for detecting an object located in front of an ultrasonic transducer.

[0002]

2. Description of the Related Art A conventional ultrasonic sensor is provided at, for example, a corner of an automobile and detects the presence or absence of an obstacle near the corner while sitting in a driver's seat, and will be described with reference to FIGS. This ultrasonic sensor is an ultrasonic transducer
1, transmit amplifier 2, receive amplifier 3, and detector
4; a microcomputer 7;

[0003] Ultrasonic transducers 1, transmission and reception have what is a by vibrator unit 1a and the horn portion 1b of the integrated ultrasound receiving transmit signals A ₁ from the amplified microcomputer 7 It transmits a pulse signal and receives a reflected wave from an object.

The transmission amplifier 2 amplifies the transmission signal A ₁ from the microcomputer 7. The receiving amplifier circuit 3 is composed of the ultrasonic vibrator 1
Amplifies the signal of the reflected wave from the received object.

[0005] The detection circuit 4 extracts a signal having a predetermined level or more from the reception signal amplified by the reception amplification circuit 3.

The microcomputer 7 is connected to an external power supply D, outputs a transmission signal A ₁ for intermittently oscillating the ultrasonic vibrator 1 via a transmission amplification circuit 2, and receives a signal from the detection circuit 4. The signal is processed to detect the presence of an object within the detection range, and to measure the length of reverberation immediately after transmission and the peak value of the transmission waveform to determine abnormalities in the ultrasonic transducer 1 and its surroundings. Then, a display or audio signal is output to drive a notifying means described later.

The notification means 6 is a display or a speaker for display, and is driven by the microcomputer 7.

[0008]

In the ultrasonic sensor as described above, as shown in FIGS. 4 and 5, an ultrasonic vibrator opens a horn portion in front of the ultrasonic transducer to the outside, and an ultrasonic sensor is used. Since it is provided so as to be exposed at the corner, foreign matter easily adheres to the concave portion formed by the vibrating surface of the ultrasonic vibrator and the horn portion and around the concave portion. If this foreign substance absorbs ultrasonic waves such as snow, the ultrasonic transducer 1 and its surroundings are detected by measuring the length of reverberation immediately after transmission and the peak value of the transmission waveform. Therefore, the presence of the foreign matter cannot be detected, so that an erroneous detection that there is no object despite the presence of an obstacle in front of the ultrasonic vibrator is performed. For this reason, the reliability of use in snowy regions is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to detect the attachment of a foreign substance such as snow which absorbs ultrasonic waves to an ultrasonic transducer. An object of the present invention is to provide an ultrasonic sensor capable of notifying an abnormality.

[0010]

In order to achieve the above-mentioned object, an ultrasonic sensor according to the present invention intermittently transmits an ultrasonic pulse signal by an ultrasonic vibrator and simultaneously transmits an ultrasonic pulse signal to a next transmission. In the ultrasonic sensor that receives the reflected wave from the object between the waves and detects the presence of the object within the predetermined detection range and the abnormality around the ultrasonic transducer, the received signal level is amplified from the predetermined at an appropriate timing. Control means for causing the control means to detect a reflected wave of an object (monitor object) which is amplified from a predetermined position and which is at a predetermined position with respect to the ultrasonic transducer and whose presence is not normally detected, and And a determination unit for determining the presence or absence.

[0011]

According to this structure, the control means amplifies the received signal level at a proper timing from a predetermined level, so that the object which is not normally detected at a predetermined position with respect to the ultrasonic vibrator. The signal level of the reflected wave of the (monitor object) is amplified above the detection level so that it can be detected, and by detecting the presence or absence of the reflected wave, an abnormality around the ultrasonic transducer is detected.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. Members that are substantially the same as those of the above-described conventional example will be described with the same reference numerals.

[0013] 1 in the ultrasonic transducer, transmission and reception be of integral has a vibrator unit and the horn portion, receiving ultrasonic a transmitting signal A ₁ from the amplified described later microcomputer It transmits a pulse signal and receives a reflected wave from an object.

[0014] 2 in the transmit amplifier, for amplifying a transmit signal A ₁ from the microcomputer to be described later. Numeral 3 denotes a reception amplification circuit which amplifies a signal of a reflected wave from an object received by the ultrasonic transducer 1. The adjustment of the amplification is controlled by a control unit of a microcomputer described later in at least a predetermined stage and two stages in which the amplification is performed more than the predetermined stage.

Reference numeral 4 denotes a detection circuit which extracts a signal having a predetermined level or more from the reception signal amplified by the reception amplification circuit 3.

[0016] 5 is a microcomputer, which is connected to an external power source D, a transmitting output unit 5a for outputting a transmit signal A ₁ for intermittently oscillate the ultrasonic vibrator 1 via the transmitting amplifier 2, Clocking means 5b for starting operation in synchronization with the transmission, and using the clocking means 5b, processes the signal received from the detection circuit 4 to detect the presence (presence and distance) of an object within the detection range. A signal processing means 5c for outputting a display or audio signal to drive a notifying means to be described later, a control means 5d for controlling the adjustment of the amplification of the receiving amplifier circuit 3 at an appropriate timing, and A determination means 5e for determining an abnormality when the signal is not detected even if the signal is further amplified, and when the reception amplification is further amplified than normal, the reflected wave of an object (monitor object) whose presence is not normally detected To be able to receive this reflection Determine the presence or absence of, and drives the informing means to be described later outputs a display or voice signal if no reflected waves.

The notification means 6 is a display or a speaker for display, and is driven by the microcomputer 5.

Next, the operation will be described with reference to the timing charts of FIGS. 2 (a) to 2 (d).

A ₀ is the waveform of the transmission signal A ₁ which is amplified and applied to the ultrasonic transducer 1. The transmission signal A ₁ is intermittent (T
Is output from the microcomputer 5 _per hour).

B ₁ is an amplified waveform of the received signal received by the ultrasonic transducer 1 when there is no object within the detection range, and the reverberation signal B ₁₁ immediately after transmission and a predetermined detection level or less. that object is outside the detection range (monitoring object), for example, the reflected signal B ₁₂ of the reflected wave of the T ₂ hours after from the ground, are included. This received signal is input to the detection circuit 4.

C ₁ is an extraction signal from the received signal input to the microcomputer 5 when no object is within the detection range. The extracted signal c ₁ is informed that there is no object within the detection range is the signal processing by the microcomputer 5.

B ₂ is the waveform of the received signal received by the amplified ultrasonic transducer 1 when there is an object within the detection range, and includes the reverberation signal B ₁₁ immediately after transmission and T ₂ from the ground. the reflected signal B ₁₂ of a predetermined detection level or less is a reflection wave of time after, the predetermined detection level or more of the reflected signal B ₁₃ is a reflected wave of T ₃ hours after from the object, are included. This received signal is
The signal is input to the detection circuit 4.

C ₂ is an extraction signal from the received signal input to the microcomputer 5 when an object is within the detection range. The extracted signal c ₂ is informed that there is an object within the detection range is the signal processing by the microcomputer 5.

[0024] b ₃ are placed if there is no object within the predetermined detection range, when the reception amplifying circuit 3 is further amplified than usual by the control unit 5d of the microcomputer 5, the ultrasonic transducer 1 is reception Reverberation signal immediately after transmission with the amplified waveform of the received signal
And B _11, and the reflected signal B ₁₂ amplified than normal at the reflection wave of the T ₂ hours after from the ground, are included. This received signal is input to the detection circuit 4.

C ₃ is a signal received by the microcomputer 5 when the receiving amplifier circuit 3 is amplified more than usual by the control means 5 d of the microcomputer 5 when there is no object within the predetermined detection range. This is an extracted signal from the signal. The extracted signal c ₃ does not occur is notified from the determination if it is the signal processing by the microcomputer 5 that there is a ground outside a predetermined detection range notification unit 6. If this notification is not given, it means that the transmitting and receiving of the ultrasonic transducer 1 is operating normally.

B ₄ is an amplified waveform of the received signal received by the ultrasonic transducer 1 when the receiving amplifier circuit 3 is further amplified by the control means 5 d of the microcomputer 5 than usual. There is only reverb signal B ₂₁ immediately after, reflected waves from an object or the ground has not been detected. This received signal is input to the detection circuit 4.

C ₄ is a receiving amplifier circuit for controlling the microcomputer 5
This is an extraction signal from the received signal input to the microcomputer 5 when the signal is amplified further than usual in 5d. The extracted signal c ₄ is determined that there is no reflected wave from the signal processed by the object or the ground by the microcomputer 5, alarm means 6 notifies an abnormality.

[0028] The ultrasonic sensor is transmitted at the start a ₀ of the waveform, when there is no object within the predetermined detection range
b ₁ , if there is an object within the predetermined detection range, receive the waveform of b ₂ (output of the receiving amplifier circuit), and if there is no object within the predetermined detection range, c ₁ , within the predetermined detection range If there is an object
c Perform signal processing of the waveform of ₂ to detect the presence or absence of an object. Then, by the control unit 5d further amplifies than normal amplification of the received at an appropriate timing, there is then to receive b ₃ of the reflected waves of the object is not detected (monitored object) in the normal, the reflected wave The presence or absence of the reflected wave is determined, and if there is no reflected wave, the notification means 6 displays the abnormality or outputs an audio signal to notify the user.

The timing for amplifying the reception more than usual may be set to a certain time after the start. Further, a fixed cycle may be repeated. Further, when the time T ₂ for returning from the ground is longer than the maximum time T ₃ for returning from the object, normal amplification is performed during the time T ₃ , and thereafter, the subsequent amplification is performed. May be provided in one transmission cycle so as to amplify more than usual.

[0030]

According to the ultrasonic sensor of the present invention, the control means amplifies the received signal level from a predetermined timing at an appropriate timing by the control means, so that the ultrasonic sensor is positioned at a predetermined position with respect to the ultrasonic transducer. Therefore, the signal level of the reflected wave of an object whose presence is not normally detected (monitor object) can be amplified above the detection level so that it can be detected. By determining the presence or absence of this reflected wave, abnormalities around the ultrasonic transducer can be detected. Since the detection is performed, it is possible to detect the adhesion of a foreign substance such as snow which absorbs the ultrasonic wave to the ultrasonic vibrator, and to notify the abnormality. As a result, the reliability of use in snowy regions can be improved.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, in which (a) is a circuit block diagram and (b) is a flowchart diagram.

FIG. 2 is also a timing chart,
(a) is when there is no object in the predetermined detection range and reception amplification is normal, (b) is when there is an object in the predetermined detection range and reception amplification is normal, and (c) is in the predetermined detection range (D) is the case where the reception amplification is further amplified than usual and the reflected wave is not received when there is an object outside and the reception amplification is further amplified than usual.

FIG. 3 shows a conventional example, in which (a) is a circuit block diagram,
(b) is a timing chart.

FIG. 4A is a schematic diagram of an ultrasonic vibrator, and FIG. 4B is a schematic diagram of an ultrasonic vibrator to which foreign matter is attached.

FIG. 5 is a perspective view similarly provided at a corner of an automobile.

[Explanation of symbols]

 1 Ultrasonic transducer 2 Transmitting and amplifying circuit 3 Receiving and amplifying circuit 4 Detection circuit 5 Microcomputer 5d Control means 5e Judgment means 6 Notification means

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI H04R 17/00 330 H04R 17/00 330Z (JP, A) JP-A 3-27381 (JP, U) JP-A 64-30465 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01V 1/00 G01B 17 / 00 G01R 19/165 G01S 15/04 H04R 3/00 330 H04R 17/00 330

Claims (1)

(57) [Claims] An ultrasonic transducer intermittently transmits an ultrasonic pulse signal, receives a reflected wave from an object between a transmitted wave and a next transmitted wave, and detects the presence of an object within a predetermined detection range. And an ultrasonic sensor for detecting an abnormality around the ultrasonic transducer. At an appropriate timing, a control means for amplifying a received signal level from a predetermined level, and a control means for amplifying the received signal level from a predetermined level to the ultrasonic vibrator. An ultrasonic sensor, comprising: a detecting means for detecting a reflected wave of an object (monitor object) which is not normally detected at a predetermined position and which determines the presence or absence of the reflected wave.