JPH06331742A - On-board ultrasonic sensor unit - Google Patents

Abstract

PURPOSE:To provide an on-board ultrasonic sensor unit which can detect and indicate the abnormal state of the sensor unit itself. CONSTITUTION:A microcomputor 6 normally delivers transmission signals to five ultrasonic oscillators 5 through an amplifier circuit 7a thus driving them. At the time of abnormality deciding operation, the transmission signals are delivered through an amplifier circuit 7b to three ultrasonic sensors 5, i.e., the central sensor and the sensors at the opposite ends, thus driving the three sensors. In other words, the pitch of arrangement is doubled as compared with normal detecting operation to decrease the number of sensors thus forming a main beam and a grating beam. Although a pavement is present in a set detection area at the time of abnormality deciding operation, the pavement can not be detected if the operational sensitivity is lowered at an ultrasonic detecting section 1 or the detecting section 1 is disabled. In such a case, the microcomputor 6 drives an abnormality indication LEDa through a driver 9a to notify the abnormal state to an operator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle ultrasonic sensor device for detecting obstacles and human bodies using ultrasonic waves.

[0002]

2. Description of the Related Art An ultrasonic sensor device uses ultrasonic waves for sensing, and ultrasonic wave pulse signals are intermittently transmitted from an ultrasonic wave oscillator to prevent obstacles and human bodies existing in the vicinity from being transmitted. By receiving the reflected wave of, the obstacle and the human body are detected.

[0003]

By the way, conventionally, the ultrasonic sensor device has a feature that the detection range can be limited and the distance can be measured, and has been used for an on-vehicle obstacle detector, a human body detector and the like. However, when used outdoors, snow or mud may adhere to the ultrasonic vibrator, or the ultrasonic vibrator may freeze.In these cases, the operating sensitivity decreases and obstacles and the human body are in the detection range. There is a problem that a detection operation is unreliable due to an inoperative state in which it cannot be detected even if it exists inside.

The present invention has been made in view of the above problems, and an object thereof is to provide a vehicle-mounted ultrasonic sensor device capable of detecting and displaying an abnormal state of the device itself.

[0005]

In order to achieve the above object, according to the invention of claim 1, an ultrasonic pulse signal is transmitted, and a reflected wave from an object by the transmitted ultrasonic pulse signal is received. In an on-vehicle ultrasonic sensor device that oscillates to detect an object, a plurality of ultrasonic transducers are arranged on the same plane, and only the main lobe is formed during normal detection operation. Of the ultrasonic transducers is selected to transmit and receive waves by selecting any of the ultrasonic transducers in the above ultrasonic transducers so that a grating lobe for road surface detection or vehicle body detection is formed during an abnormality determination operation. A means for transmitting and receiving waves, determining that it is normal when there is a reflected wave from the road surface or vehicle body, and determining that it is abnormal when there is no received reflected wave from the road surface or vehicle body, and displaying an anomaly With That.

According to a second aspect of the invention, in the first aspect of the invention, the abnormality determining operation is performed within a predetermined time after the power is turned on, and the normal detecting operation is performed outside the predetermined time. According to a third aspect of the present invention, in the first or second aspect of the invention, at the time of the abnormality determination operation, the reflected wave from the road surface or the vehicle body is received to calculate the distance from the ultrasonic transducer to the road surface or the vehicle body, and the calculation is performed. The receiving gain of the receiving circuit is controlled according to the distance.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the distance from the ultrasonic transducer to the road surface or the vehicle body is calculated by receiving a reflected wave from the road surface or the vehicle body during the abnormality determining operation. Then, the phases of the transmitted waves of the plurality of ultrasonic transducers arranged on the same plane are sequentially shifted according to the calculated distance to drive the ultrasonic transducers to control the beam direction of the main lobe.

[0008]

According to the invention of claim 1, an abnormality determining operation for detecting an abnormality of the apparatus itself can be performed, and when it is determined to be abnormal, the driver can be warned by the display, and the driver can be alerted. It can provide safe driving. According to the second aspect of the present invention, the abnormality determination can be performed immediately after the start of operation, so that it is possible to prevent the occurrence of trouble during traveling due to an inoperative state.

According to the invention of claim 3 and the invention of claim 4, even when the distance from the ultrasonic transducer to the road surface or the vehicle body is shorter than a predetermined value, the gain of the receiving circuit can be reduced during normal detection operation. By making the beam of the main lobe upward, it is possible to prevent erroneous detection of the road surface or the vehicle body.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) In a vehicle-mounted ultrasonic sensor device, as shown in FIGS. 2 and 3, an ultrasonic detecting unit 1 is attached to a bumper or the like of a vehicle body 2, and ultrasonic pulse signals are intermittently supplied from the ultrasonic detecting unit 1. By transmitting a wave and receiving a reflected wave from an obstacle existing in the periphery of the vehicle body 2 or a human body, the obstacle and the human body are detected, and this detection is displayed to the driver. The main body 3 for controlling the operation of the ultrasonic wave detecting unit 1 is mounted inside the vehicle compartment or the trunk, and the display unit 4 for displaying an alarm is mounted near the driver's seat.

As shown in FIG. 1, the main body 3 has a plurality of ultrasonic transducers 5 constituting the ultrasonic detector 1 connected by signal lines, and a microcomputer 6 provided in the main body 3.
The ultrasonic wave signal is generated by the ultrasonic wave detecting unit 1 from the ultrasonic wave detecting unit 1 by driving the ultrasonic wave wave generator 5a or 7b to all the ultrasonic wave oscillators 5 or a predetermined ultrasonic wave oscillator 5 to drive them. The waves are transmitted intermittently. Further, the reflected wave from the obstacle or the human body is received by the ultrasonic transducer 5 and converted into an electric signal, and the received signal is amplified by the amplifier circuit 8a or 8b constituting the wave receiving circuit and then taken in by the microcomputer 6. The microcomputer 6 counts the time from the transmission of the transmitted wave to the reception of the reflected wave to calculate the distance from the ultrasonic detecting section 1 to the reflecting object. The power supply of the main body 3 is obtained from the power supply 10 that converts the power supply voltage of the battery 11 into a predetermined voltage.
The clock generator 12 supplies a reference clock to the microcomputer 6.

As shown in FIG. 4, the ultrasonic detector 1 is a unit for arranging a plurality of ultrasonic vibrators 5 on the same plane at a predetermined pitch d to form directivity. The micro computer 6 selects 5 to change the directivity depending on the arrangement pitch and the number thereof.
Here, for example, when five ultrasonic transducers 5 are arranged at an arrangement pitch of 0.5λ, a main lobe as shown in FIG. 5A is formed, and five ultrasonic transducers 5 are arranged at an arrangement pitch of 1.0λ. When the ultrasonic transducers 5 are arranged, a main lobe and a grating globe as shown in FIG. 5C are formed. The array of the ultrasonic transducers 1 is not limited to the above condition. For example, when 10 arrays are arranged at an array pitch of 0.5λ, main lobes are formed as shown in FIG. When 10 pieces are arranged at a pitch of 1.0λ, a main lobe and a grating lobe can be formed as shown in FIG.

Therefore, in the circuit of FIG. 1 of the present embodiment, during normal detection operation, the microcomputer 6 applies a transmission signal to all five ultrasonic transducers 5 through the amplifier circuit 7a to drive them, and at the time of abnormality determination operation. A microcomputer 6 applies a transmission signal to three ultrasonic transducers 5 at both ends and the center through an amplifier circuit 7b to drive them. That is, the main lobe is formed during the normal operation, the array pitch is doubled during the abnormality determination operation, and the main lobe and the grating lobe are formed by reducing the number.

Thus, in this embodiment, when the power is turned on as shown in the flow chart of FIG. 6, the microcomputer 6 first enters an abnormality determining operation during a predetermined period T1.
The ultrasonic wave transducers 5 at both ends and in the center are supplied with a transmission signal through the amplifier circuit 7b and driven, that is, the array pitch is doubled at the time of the normal detection operation, and the number is reduced to form the main lobe and the grating lobe. Then, the detection areas X _{1 to} X ₃ in FIG. 7B are set.

At the time of this abnormality determination operation, the road surface Y always exists in the detection area X ₁ , and the ultrasonic wave detection unit 1
Snow on the sensing surface of the ultrasonic transducer 5 of
The road surface Y will always be detected if there is no reduction in motion and inactivity due to adhesion of mud, etc., but if snow or dirt, mud, etc. adheres to the detection surface, or if it freezes. Becomes unable to detect the road surface Y due to a decrease in operation sensitivity and a non-operation state. Therefore, the make-ro computer 6 determines that the ultrasonic wave detection unit 1 is operating normally if there is a received wave input R1 of the reflected wave from the road surface Y at the time of the abnormality determination operation. 9a
Through the light emitting diode LEDa for displaying an abnormality of the display unit 4.
To inform the driver that there is an abnormal condition.

When it is judged to be normal, the microcomputer 6 carries out a normal detection operation, and sends a transmission signal to all of the five ultrasonic transducers 5 through the amplifier circuit 7a to drive them, and FIG. The detection area X shown in is set. During this normal detection operation, if there is a wave receiving input R2 of a reflected wave from an obstacle or a human body, the microcomputer 6
Calculates the distance to the obstacle or the human body by counting the time from the transmission to the reception input, and drives the detection display light emitting diode LEDb of the display unit 4 through the driver 9b if the distance is within a predetermined range. Informing the driver that obstacles and the human body are near the vehicle body.

Although the grade lobe is formed during the abnormality determination operation to detect the road surface Y, the abnormality determination may be performed by detecting the vehicle body surface or the protruding portion of the vehicle body. In addition to the arrangement of the ultrasonic detecting elements 5 of the ultrasonic detecting unit 1 in a line as in the above embodiment,
Various arrangements are conceivable as shown in FIGS. 8 (a) and 8 (b).

(Embodiment 2) In the present embodiment, as shown in FIG. 9, the amplifier circuit 8a of the wave receiving circuit used during the normal detection operation has a gain whose gain can be controlled by the microcomputer 6. Therefore, when the reflected wave from the road surface Y (or the vehicle body) is received during the abnormality determination operation, the ultrasonic detector 1
If the distance from the vehicle to the road surface Y (or the vehicle body) is shorter than the predetermined distance (the mounting height from the road surface Y is low),
The gain of the amplifier circuit 8a is reduced by the signal from the microcomputer 6 so that the road surface Y (or the vehicle body) is not erroneously detected by the main lobe during the normal detection operation.

(Embodiment 3) This embodiment is an ultrasonic detector 1
In the abnormality detection operation used during the normal detection operation, when the reflected pulse from the road surface Y (or the vehicle body) is used, the distance from the ultrasonic detection unit to the road surface Y (or the vehicle body) is shorter than a predetermined distance ( In the case where the mounting height from the road surface Y is low), during normal detection operation, the phases of the transmission waves of the plurality of ultrasonic transducers 5 arranged on the same plane are sequentially shifted to drive the beam of the main lobe. To control the direction to be upward. A phase shifter 12 which can be controlled by a signal from the microcomputer 6 is provided.

[0020]

In order to achieve the above-mentioned object, claim 1
In the invention, a plurality of ultrasonic transducers are arranged on the same plane, and any ultrasonic element in the ultrasonic transducer is selected and transmitted / received so that only the main lobe is formed during normal detection operation. Waves are transmitted and received by selecting any ultrasonic transducer among the above ultrasonic transducers so that a grating lobe for road surface or vehicle body detection is formed during abnormality determination operation, and then reflected from the road surface or vehicle body. When there is a received wave, it is judged to be normal, and when there is no reflected wave from the road surface or the vehicle body, it is judged to be abnormal and means for displaying an anomaly are provided. There is an effect that an abnormality determination operation for detection can be performed, and when it is determined that the abnormality is detected, the driver can be warned by the display, and as a result, safe driving can be provided to the driver.

According to a second aspect of the invention, in the first aspect of the invention, the abnormality determining operation is performed within a predetermined time after the power is turned on, and the normal detecting operation is performed outside the predetermined time. Immediately after the start, it is possible to determine the abnormality, and therefore, it is possible to prevent the occurrence of trouble during traveling due to an inoperative state.

According to a third aspect of the present invention, during the abnormality determining operation, the reflected wave from the road surface or the vehicle body is received to calculate the distance from the ultrasonic transducer to the road surface or the vehicle body, and the received wave is received according to the calculated distance. Since the gain of the circuit is controlled, the invention of claim 4 receives the reflected wave from the road surface or the vehicle body at the time of the abnormality determining operation to receive the distance from the ultrasonic transducer to the road surface or the vehicle body. Is calculated and driven by sequentially shifting the phases of the plurality of ultrasonic transducers arranged on the same plane according to the calculated distance to control the beam direction of the main lobe. Even if the distance from the vibrator to the road surface or vehicle body is shorter than a predetermined value, it is possible to prevent false detection of the road surface or vehicle body by reducing the gain of the receiving circuit or raising the main lobe during normal detection operation. That there is an effect that it is.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a relationship between a vehicle body mounted on the above and a detection area.

FIG. 3 is a layout configuration diagram of each unit of the above.

FIG. 4 is an explanatory view of the arrangement of ultrasonic transducers of the ultrasonic detection unit of the above.

FIG. 5 is an array pitch and the number of ultrasonic transducers of the above,
It is a relationship explanatory view with a beam.

FIG. 6 is a flowchart for explaining the same operation as above.

FIG. 7 is an explanatory diagram of forming a detection area in the above.

FIG. 8A is a perspective view of another example of the ultrasonic wave detection unit of the above. FIG. 7B is a perspective view of another example of the ultrasonic wave detection unit of the above.

FIG. 9 is a circuit configuration diagram of a second embodiment of the present invention.

FIG. 10 is a circuit configuration diagram of a third embodiment of the present invention.

[Explanation of symbols]

 1 Ultrasonic Detector 3 Main Body 4 Display 5 Ultrasonic Transducer 6 Microcomputer 7a, 7b Amplifying Circuit 8a, 8b Amplifying Circuit 9a, 9b Driver 10 Power Supply LEDa Abnormality Display Light Emitting Diode LEDb Detection Display Light Emitting Diode

Claims (4)

[Claims] 1. An in-vehicle ultrasonic sensor device for detecting an object by transmitting an ultrasonic pulse signal and receiving a reflected wave from an object due to the transmitted ultrasonic pulse signal. The transducers are arranged on the same plane, and any ultrasonic element in the ultrasonic transducer is selected to transmit and receive waves so that only the main lobe is formed during normal detection operation. Or, when any ultrasonic transducer among the above ultrasonic transducers is selected to transmit / receive a wave so that a grating lobe for vehicle body detection is formed, it is normal when a reflected wave from the road surface or the vehicle body is received. A vehicle-mounted ultrasonic sensor device, comprising means for judging that there is an abnormality, and for displaying an abnormality when there is no reception of a reflected wave from a road surface or a vehicle body. 2. The on-vehicle ultrasonic sensor device according to claim 1, wherein the abnormality determination operation is performed within a predetermined time after the power is turned on, and the normal detection operation is performed outside the predetermined time. 3. The receiving gain of the receiving circuit according to the calculated distance by receiving the reflected wave from the road surface or the vehicle body during the abnormality determining operation to calculate the distance from the ultrasonic transducer to the road surface or the vehicle body. The in-vehicle ultrasonic sensor device according to claim 1, wherein the ultrasonic sensor device according to claim 1 is controlled. 4. The distance from the ultrasonic transducer to the road surface or the vehicle body is calculated by receiving the reflected wave from the road surface or the vehicle body during the abnormality determining operation, and the distance is arranged on the same plane according to the calculated distance. The vehicle-mounted ultrasonic sensor device according to claim 1 or 2, wherein the plurality of ultrasonic transducers are driven by sequentially shifting the phases of the transmitted waves to control the beam direction of the main lobe.