JP2012073052A - Obstacle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an obstacle detector capable of informing persons behind a vehicle about backing when the vehicle is backing at low cost.SOLUTION: Multiple ultrasonic transmission parts 31 and 32 mounted on the rear part of a vehicle 2 transmit ultrasonic waves when the vehicle 2 is backing. An ultrasonic reception section 4 receives the ultrasonic waves which were transmitted from the ultrasonic transmission parts 31 and 32, reflected by an obstacle 7 and are returning towards the vehicle. A control circuit 5 detects the obstacle 7 behind the vehicle based on the ultrasonic waves received by the ultrasonic reception section 4. When the vehicle is backing, the multiple ultrasonic transmission parts 31 and 32 transmit ultrasonic waves at frequencies which are different from each other and between which difference generates an audible sound.

Description

  The present invention relates to an obstacle detection device, and in particular, a plurality of ultrasonic transmission units that are installed at the rear or front of a vehicle and transmit ultrasonic waves when the vehicle is moving backward or forward, and transmitted from the ultrasonic transmission unit. Ultrasonic wave receiving means for receiving ultrasonic waves reflected back from the obstacle, and obstacle detection means for detecting obstacles behind or in front of the vehicle based on the ultrasonic waves received by the ultrasonic wave receiving means And an obstacle detection device comprising:

  Conventionally, as shown in FIGS. 4 and 5, there are known obstacle detection devices that detect an obstacle when a vehicle is moving backward using an ultrasonic transducer and notify the driver in the vehicle to that effect ( Patent Documents 1 and 2). As shown in FIG. 4, the obstacle detection apparatus 1 includes an ultrasonic transmission unit 31 and an ultrasonic reception unit 4 installed behind the vehicle 2, for example, in a bumper.

  As shown in FIG. 5, the ultrasonic transmission unit 31 includes an ultrasonic transducer 33 and a transmission circuit 35 that vibrates the ultrasonic transducer 33 and emits ultrasonic waves of about 40 kHz toward the rear of the vehicle 2. And have. The ultrasonic receiving unit 4 receives an ultrasonic transducer 41 and ultrasonic waves transmitted from the ultrasonic transmitting unit 31 and reflected back from the obstacle by detecting the vibration of the ultrasonic transducer 41. Receiving circuit 42.

  The ultrasonic transmitter 31 and the ultrasonic receiver 42 are controlled by a control circuit 5 including a CPU and the like. The control circuit 5 controls the ultrasonic transmission unit 31 when the vehicle 2 moves backward to radiate ultrasonic waves toward the rear of the vehicle 2. Then, the control circuit 5 measures the time difference between the ultrasonic wave transmitted by the ultrasonic wave transmission unit 31 and the ultrasonic wave received by the ultrasonic wave reception unit 4, calculates the distance to the obstacle 7, and within a certain distance When the obstacle 7 is detected, the in-vehicle speaker 6 is controlled to notify the driver in the vehicle.

  However, although the obstacle detection apparatus 1 described above can notify the driver in the vehicle 2 that the obstacle 7 has been detected, the person behind the vehicle 2 (obstacle) is informed of the vehicle. I can't tell you that 2 is moving backwards. Since the ultrasonic wave transmitted from the ultrasonic wave transmission unit 31 is not audible sound, it cannot be heard by a person behind the vehicle 2. For this reason, pedestrians behind the vehicle 2 cannot be informed of the backward movement of the vehicle 2 and cannot be quickly evacuated.

  Therefore, there is also known a vehicle retraction warning device that transmits a retreat of the vehicle 2 to a person behind the vehicle 2 using a speaker installed behind the vehicle 2 (Patent Document 3). However, the vehicle reverse alarm device has a problem in terms of cost because it is necessary to install a speaker behind the vehicle 2 only to inform the person outside the vehicle of the reverse of the vehicle 2.

Japanese Patent Laid-Open No. 2003-130952 JP 2008-273251 A Japanese Patent Laid-Open No. 7-117560

  Then, this invention makes it a subject to provide the obstruction detection apparatus which can tell that to the person who exists in the back of a vehicle at the time of a vehicle reverse at low cost.

  The invention according to claim 1 for solving the above-described problem is an ultrasonic transmission unit that transmits ultrasonic waves when the vehicle is moving backward or forward, and is transmitted from the ultrasonic transmission unit. Ultrasonic wave receiving means for receiving the ultrasonic wave reflected and returned, obstacle detection means for detecting the obstacle behind the vehicle based on the ultrasonic wave received by the ultrasonic wave receiving means, In the obstacle detection apparatus, the ultrasonic transmission means is provided in a plurality, and the plurality of ultrasonic transmission means have different frequencies when the vehicle is moving backward or forward, and the difference between the different frequencies is audible sound. It exists in the obstruction detector characterized by being provided so that the ultrasonic wave of the frequency which becomes may be transmitted.

  As described above, according to the first aspect of the present invention, when ultrasonic waves are transmitted by a plurality of ultrasonic transmission means in order to detect an obstacle when the vehicle is moving backward or when the vehicle is moving forward, a plurality of ultrasonic transmission means are used. The frequency difference between the transmitted ultrasonic waves becomes an audible sound that can be heard by a person behind or ahead of the vehicle. Therefore, since the ultrasonic transmission means for detecting the obstacle can be used as a speaker for transmitting the vehicle backward or the vehicle forward to a person behind or ahead of the vehicle, the vehicle can be inexpensively moved backward or forward. This can be communicated to a person behind or in front of the vehicle. Moreover, since the characteristics of ultrasonic waves are utilized to realize a speaker with a narrow beam width and high palatability, the sound cannot be heard by people who are not behind or in front of the vehicle. There is no.

It is the schematic for showing one Embodiment of the obstruction detection apparatus of this invention. It is a detailed electric circuit diagram of the obstacle detection apparatus shown in FIG. It is a flowchart which shows the process sequence in the obstacle detection process of CPU which comprises the obstacle detection apparatus shown in FIG. It is the schematic for showing an example of the conventional obstacle detection apparatus. It is a detailed electrical circuit diagram of the obstacle detection apparatus shown in FIG.

  Hereinafter, the obstacle detection device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of the obstacle detection apparatus of the present invention. FIG. 2 is a detailed electric circuit diagram of the obstacle detection apparatus shown in FIG.

  As shown in the figure, the obstacle detection apparatus 1 includes an ultrasonic transmission unit 31 and 32 as a plurality of ultrasonic transmission units installed behind a vehicle 2, for example, a bumper, and an ultrasonic reception unit as an ultrasonic reception unit. Unit 4, ultrasonic transmission units 31 and 32, control circuit 5 as an obstacle detection unit for controlling ultrasonic reception unit 4, and in-vehicle speaker 6.

  As shown in FIG. 2, the ultrasonic transmitters 31 and 32 respectively radiate ultrasonic waves toward the rear of the vehicle 2 by vibrating the ultrasonic vibrators 33 and 34 and the ultrasonic vibrators 33 and 34. Transmission circuits 35 and 36 to be transmitted. The transmission circuits 35 and 36 include oscillators 35A and 36A that oscillate pulse signals, and amplifiers 35B and 36B that amplify the pulse signals output by the oscillators 35A and 36A.

  The oscillators 35A and 36A oscillate at frequencies that are different from each other and at which a difference between the different frequencies becomes an audible sound. The oscillators 35 </ b> A and 36 </ b> A are connected to the control circuit 5, and the oscillation is controlled by the control circuit 5.

  The amplifiers 35B and 36B amplify the pulse signals output from the oscillators 35A and 36A and output the amplified pulse signals to the ultrasonic transducers 33 and 34. The ultrasonic transducers 33 and 34 oscillate at the frequency of the pulse signal supplied from the amplifiers 35 </ b> B and 36 </ b> B and radiate ultrasonic waves to the rear of the vehicle 2.

  The ultrasonic receiver 4 detects the vibration of the ultrasonic transducer 41 and the ultrasonic transducer 41 and transmits the ultrasonic wave transmitted from the ultrasonic transmitters 31 and 32 to reflect the obstacle 5 and returns. And a receiving circuit 42 for receiving sound waves.

  The ultrasonic transducer 41 vibrates when receiving ultrasonic waves transmitted from the ultrasonic transmission units 31 and 32 and reflected back from the obstacle 5, and converts the vibrations into pulse signals to receive circuits. Output to 42. The receiving circuit 42 amplifies the pulse signal output from the ultrasonic transducer 41 or shapes the waveform and outputs it to the control circuit 5.

  The control circuit 5 is composed of, for example, a CPU and the like. When the gear of the vehicle 2 becomes a back gear and the backward movement of the vehicle 2 is detected, the control circuit 5 controls the ultrasonic transmission units 31 and 32 and the ultrasonic reception unit 4 described above. Obstacle detection processing for detecting an obstacle behind the vehicle 2 is performed.

  The in-vehicle speaker 6 is installed in a vehicle such as an instrument panel of the vehicle 2 and, as a result of the obstacle detection processing performed by the control circuit 5, when an obstacle is detected behind the vehicle 2, a message to that effect is given to the driver. Outputs voice guidance to communicate.

  The detailed operation of the obstacle detection apparatus 1 described in the above outline will be described below with reference to FIG. First, the control circuit 5 starts an obstacle detection process when the gear of the vehicle 2 becomes a back gear. First, the control circuit 5 controls the oscillators 35A and 36A of the transmission circuits 35 and 36 to cause the oscillators 35A and 36A to oscillate simultaneously (step S1). As a result, the oscillators 35A and 36 output pulse signals having frequencies different from each other and a frequency at which the difference between the different frequencies becomes an audible sound.

  The pulse signals output from the oscillators 35A and 36A are amplified by the amplifiers 35B and 36B, and then output to the ultrasonic transducers 33 and 34, respectively. As a result, the ultrasonic transducers 33 and 34 vibrate and ultrasonic waves are radiated to the rear of the vehicle 2. That is, ultrasonic waves having different frequencies from each other and radiating from the ultrasonic transducers 33 and 34 are audible sound.

  When ultrasonic waves having different frequencies are radiated simultaneously in the same direction as described above, many harmonics and coupled sounds are generated by a medium such as air. Among these frequency components, an audible sound that is the difference between the ultrasonic wave radiated from the ultrasonic transducer 33 and the ultrasonic wave radiated from the ultrasonic transducer 34 is heard by a person behind the vehicle 2. That is, the ultrasonic transducers 33 and 34 function as parametric speakers, and can generate an alarm sound for urging a person behind the vehicle 2 to retreat when the vehicle 2 moves backward.

  Next, the control circuit 5 takes in the ultrasonic wave received by the ultrasonic wave receiving unit 4 (step S2), and then transmits the ultrasonic wave from the ultrasonic wave transmitting units 31 and 32 and then reflects it to the obstacle 7. Then, a time difference until returning to the ultrasonic wave receiving unit 4 is calculated (step S3), and it is determined whether or not there is an obstacle 7 within a certain distance (step S4). If there is an obstacle 7 within a certain distance (Y in step S4), the control circuit 5 controls the in-vehicle speaker 6 to generate an alarm sound to that effect and informs the driver in the vehicle (step S5). ), It returns to step S1 again.

  On the other hand, if there is no obstacle 7 within a certain distance (N in step S4), the control circuit 5 stops the alarm sound from the in-vehicle speaker 6 (step S6), and then steps again. Return to S1. The obstacle detection process is repeatedly performed until the gear of the vehicle 2 is not a back gear.

  According to the obstacle detection device 1 described above, when the ultrasonic waves are transmitted by the two ultrasonic transmission units 31 and 32 in order to detect the obstacle 7 when the vehicle 2 moves backward, the two ultrasonic transmission units 31 and 32 are detected. The frequency difference between the ultrasonic waves transmitted by the above becomes an audible sound, which can be heard by a person behind the vehicle 2. Accordingly, since the ultrasonic transmitters 31 and 32 for detecting an obstacle can be used as a speaker for notifying a person behind the vehicle 2 of the backward movement of the vehicle 2, the fact that the vehicle 2 is backward is inexpensive. To the person behind the vehicle 2.

  Further, as shown in FIG. 3, the control circuit 5 only needs to detect the obstacle 7, and it is not necessary to incorporate a special process for notifying the backward movement of the vehicle 2. Sometimes an alarm sound can be generated for the rear. That is, only by setting the oscillation frequency of the oscillators 35A and 36A so that the difference between the frequencies transmitted from the ultrasonic transmitters 31 and 32 becomes an audible sound, an alarm sound for informing the backward movement of the vehicle 2 is generated. Therefore, the cost can be reduced.

  In addition, since the characteristics of the ultrasonic wave are utilized to realize a speaker with a narrow beam width and high palatability, the sound cannot be heard by people other than the back of the vehicle 2, and noise can be scattered around. Absent.

  In the above-described embodiment, the two ultrasonic transmission units 31 and 32 are installed, but the present invention is not limited to this. There may be a plurality of ultrasonic transmission units, and there may be three or more.

  In the above-described embodiment, the ultrasonic transmitters 31 and 32 are installed at the rear of the vehicle and transmit ultrasonic waves when the vehicle is moving backward, but the present invention is not limited to this. For example, EV cars and HEV cars travel very quietly because they are driven by an electric motor. For this reason, the pedestrian in front of the vehicle often does not notice the approach of the vehicle. Therefore, the ultrasonic transmitters 31 and 32 may be installed in front of the vehicle to transmit ultrasonic waves when the vehicle moves forward.

  In the above-described embodiment, the ultrasonic transmitters 31 and 32 always transmit ultrasonic waves having a constant magnitude, but the present invention is not limited to this. For example, the ultrasonic output may be increased in accordance with the throttle opening or the vehicle speed, that is, as the throttle opening or the vehicle speed increases, so that the alarm sound is increased.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

1 Obstacle Detection Device 4 Ultrasonic Receiver (Ultrasonic Receiver)
5 Control circuit (obstacle detection means)
31 Ultrasonic transmitter (ultrasonic transmitter)
32 Ultrasonic transmitter (ultrasonic transmitter)

Claims (1)

Ultrasound transmitting means for transmitting ultrasonic waves when the vehicle is moving backward or forward, installed behind or in front of the vehicle, and ultrasonic waves that are transmitted from the ultrasonic transmitting means and reflect the obstacles and return. In the obstacle detection apparatus comprising: a sound wave receiving unit; and an obstacle detection unit that detects an obstacle behind the vehicle based on the ultrasonic wave received by the ultrasonic wave reception unit.
A plurality of the ultrasonic transmission means are provided,
The plurality of ultrasonic wave transmitting means are provided so as to transmit ultrasonic waves having different frequencies and a frequency at which a difference between the different frequencies becomes an audible sound when the vehicle moves backward or forwards. Obstacle detection device characterized by the above.

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