JPH06242237A - Obstacle detecting sensor - Google Patents

Abstract

PURPOSE:To eliminate the erroneous operation of an ultrasonic sensor even on not only a flat road surface but also a gravel road. CONSTITUTION:The obstacle detecting sensor comprises a gate signal forming circuit 2 for deciding a distance to be detected upon reception of a wave transmission signal from a wave transmission signal forming circuit 1 for forming an electric signal for driving a microphone M, an amplifying.detector 3 for amplifying.detecting an electric signal of a sound wave due to an obstacle, a changeover switch circuit 4 for switching an amplification factor of an amplifier of the detector 3 to that in a normal detecting area and that in an extended detecting area, a waveform converter 5 for converting a waveform of the detector 3 to a digital wave, a gate circuit 5 for inhibiting to receive a sound wave returned over a gate time and a display circuit 7 for outputting a detection output when a sound wave of a predetermined level or more is reflected within the gate time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detecting sensor for a vehicle, for example, for traveling safely while watching for an obstacle existing at a rear position of an automobile.

[0002]

2. Description of the Related Art Conventionally, when an ultrasonic sensor is installed on a vehicle bumper or the like, it is installed at a position where the ultrasonic sensor does not malfunction due to detection of the road surface. The state differs depending on, for example, a flat road surface or a gravel road (the gravel road is more reflective).

[0003]

Since the gravel road has a larger detection area, even if the ultrasonic sensor is installed at a position where the vehicle is parked on a flat road surface and does not detect the road surface, the gravel road will not be detected. There is a risk of malfunction. Also, depending on the vehicle model, the size of the sinking of the vehicle height may differ depending on the fixed volume (when the maximum weight is loaded) and when the vehicle is empty. When the product sinks a lot, the ultrasonic sensor may malfunction by picking up and detecting the road surface.

In view of the above problems, the present invention provides gravel on a flat road surface even if the vehicle is parked on a flat road surface and installed at a position where the ultrasonic sensor does not pick up and detect the road surface. The purpose is to prevent the ultrasonic sensor from malfunctioning even on the road.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 provides an expanded detection area outside a normal detection area and parks it on a flat road surface for ultrasonic waves. When determining the height to install the sensor, it is characterized by increasing the amplifier gain of the sensor circuit by changing the switch of the sensor circuit from the normal detection area side to the enlarged detection area side. According to the invention of claim 2, when a detection area which is enlarged outside the normal detection area is provided and the height of the ultrasonic sensor is determined by parking the vehicle on a flat road surface, The changeover switch is changed over in several stages on the side of the enlarged detection area.

[0006]

Next, the function of the present invention will be described. An enlarged detection area is provided outside the normal detection area, and when determining the height to install the ultrasonic sensor by parking on a flat road surface, change the switch of the sensor circuit from the normal detection area side. Switching to the enlarged detection area side, or switching the changeover switch of the sensor circuit in several steps on the enlarged detection area side.

[0007]

Embodiments of the present invention will be specifically described with reference to the drawings. (Invention of Claim 1) FIG. 1 is a circuit block diagram of an obstacle detection sensor according to the invention of Claim 1.
The figure will be described. Reference numeral 1 is a transmission signal generation circuit for generating an electric signal for driving the microphone M. Reference numeral 2 is for determining the time from the reception of the transmission signal until the return of the reflected sound wave. The gate signal generating circuit 3 for determining the distance causes the sound wave bounced by an obstacle such as the floor to vibrate the microphone M again and is converted into a weak electric signal, but amplifies this weak electric signal. An amplification / detection circuit composed of an amplification unit and a detection unit that further removes the natural vibration frequency of the microphone M and takes out only the envelope of the microphone M. Reference numeral 4 indicates the amplification factor of the amplification circuit of the amplification / detection circuit 3. Changeover switch circuit for switching between the detection area X and the enlarged detection area Y, 5
Is a waveform conversion circuit for converting the waveform of the detection circuit of the amplification / detection circuit 3 into a clean on / off (0, 1) digital wave, and 6 is for not accepting a sound wave returned after the gate time is exceeded. The gate circuit 7 is a display circuit that outputs a detection output when a sound wave of a predetermined level or higher is reflected within the gate time.

In such a circuit block diagram, when a sound wave of a predetermined level or higher is reflected within the gate time, this is detected to turn on the display circuit 7, and when the expanded detection area Y is amplified. -Increase the amplification factor of the detection circuit 3. 2A and 2B show operation signal waveform diagrams in such an operation state. FIG. 2A is a transmission signal, FIG. 2B is a normal reception signal, FIG. 2C is an expansion reception signal, and FIG. Is a gate circuit signal.

FIG. 3 is an external perspective view of the obstacle detection sensor according to the first aspect of the present invention, in which a is a control circuit body and b is a control circuit body.
Is a changeover switch, c is a sensor section, d is an output circuit display section, e is a harness connecting the control circuit body a and the sensor section c, f is a harness for taking in a power circuit from the vehicle, g
Is a harness that connects the control circuit body a and the output circuit display section d.

(Invention of Claim 2) FIG. 4 is a circuit block diagram of the obstacle detection sensor in the invention of Claim 2. The configuration of each block diagram is the same as the configuration of the block diagram shown in FIG. 1, and therefore the description thereof will be omitted and only different points will be described. Reference numeral 4'denotes a changeover switch circuit. However, depending on the vehicle type, the size of the vehicle height sinks depending on the vehicle volume (when the maximum weight is fixed) and when the vehicle is empty. When the installation position of the vehicle is decided, a vehicle with a large vehicle height sinks a difference in the expanded detection area to prevent malfunctions due to picking up the road surface and detecting it during constant volume. The changeover switch circuit 4'changes to a plurality of stages so that the influence of the gravel road can be seen in consideration of the sinking amount. The operation signal waveform diagram of the operation state in this case is the same as that of FIG.

FIG. 5 is an external perspective view of the obstacle detection sensor according to the second aspect of the invention. In the figure, a is a control circuit body, b'is a changeover switch, c is a sensor section, d is an output circuit display section, e is a harness connecting the control circuit body a and the sensor section c, and f is a power supply circuit from the vehicle. The harness for taking-in g is a harness for connecting the control circuit main body a and the output circuit display portion d, but the changeover switch b ′ is a rotary switch that can be operated in several stages and can be changed over. The operation for switching to a plurality of stages is performed.

FIG. 6 is a front view showing a state in which the ultrasonic sensor S is installed in the bumper B of the vehicle K or the like, where X is a normal detection area, and the detection area Y enlarged outside thereof is shown. The state provided is shown. In this figure, G is the ground.

[0013]

As described above, according to the invention of claim 1, the height at which the ultrasonic sensor is installed by providing an enlarged detection area outside the normal detection area and parking the vehicle on a flat road surface. When deciding, select the switch of the sensor circuit,
The amplifier gain of the sensor circuit is increased by switching from the normal detection area side to the enlarged detection area side. Further, in the invention of claim 2, the sensor circuit changeover switch is provided on the enlarged detection area side. Even if the vehicle is parked on a flat road surface and installed at a position where the ultrasonic sensor does not pick up the road surface and detect it, it is possible to switch over several levels. It has the feature that it can prevent the sound wave sensor from malfunctioning.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an obstacle detection sensor according to the first aspect of the invention.

2A and 2B are operation signal waveform diagrams in the same operation state as above, in which FIG. 2A is a transmission signal, FIG. 2B is a normal reception signal, and FIG.
(C) is a received signal at the time of expansion, and (D) is a gate circuit signal.

FIG. 3 is an external perspective view of the above obstacle detection sensor.

FIG. 4 is a circuit block diagram of an obstacle detection sensor according to a second aspect of the invention.

FIG. 5 is an external perspective view of the above obstacle detection sensor.

FIG. 6 is a front view showing a state in which an ultrasonic sensor is installed on a bumper of a vehicle or the like.

[Explanation of symbols]

 1 Transmitted Signal Creating Circuit 2 Gate Signal Creating Circuit 3 Amplification / Detection Circuit 4 Changeover Switch Circuit 5 Waveform Shaping Circuit 6 Gate Circuit 7 Display Circuit M Microphone

Claims (2)

[Claims] 1. When an enlarged detection area is provided outside a normal detection area and the height at which an ultrasonic sensor is installed by parking on a flat road surface is determined, the changeover switch of the sensor circuit is normally set. The obstacle detection sensor is characterized by increasing the amplifier gain of the sensor circuit by switching from the detection area side to the enlarged detection area side. 2. An enlarged detection area is provided outside the normal detection area, and when changing the height at which the ultrasonic sensor is installed by parking on a flat road surface, the changeover switch of the sensor circuit is enlarged. Obstacle detection sensor characterized by switching in several steps on the detected area side.