JP2016014570A - Obstacle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an obstacle detection device in which a detection distance is maintained and false detection is reduced.SOLUTION: A sensor 1, attached to a vehicle, includes a transmission unit 11 for intermittently transmitting a signal wave to a space around the vehicle and a reception unit 12 for receiving a reflected wave, among the signal waves transmitted from the transmission unit 11, that is reflected by an obstacle. A detection unit 2 detects the presence of the obstacle on the basis of the reflected wave received by the reception unit 12. A storage unit 5 stores the waveform of the reflected wave received by the reception unit 12. The sensor 1 is arranged so that at least some of the signal waves transmitted from the transmission unit 11 are reflected by a road and received by the reception unit 12. The storage unit 5 stores the waveform of the reflected wave, among the signal waves transmitted from the transmission unit 11, that is reflected by the road. The arithmetic unit 3 generates a differential waveform between the waveform of the reflected wave received by the reception unit 12 and the waveform of the reflected wave stored by the storage unit 5. The detection unit 2 detects the presence of the obstacle on the basis of the differential waveform generated by the arithmetic unit 3.

Description

  The present invention generally relates to an obstacle detection device, and more particularly to an obstacle detection device that detects an obstacle using ultrasonic waves, electromagnetic waves, or the like.

  Conventionally, an obstacle detection device that detects an obstacle using ultrasonic waves has been provided (see, for example, Patent Document 1). The obstacle detection apparatus includes an ultrasonic sensor that transmits and receives ultrasonic waves and an electronic control unit (ECU) that performs various arithmetic processes for transmitting and receiving ultrasonic waves.

  In this obstacle detection device, the presence or absence of an obstacle is determined by comparing a reflected wave reflected by an obstacle or the like among ultrasonic waves transmitted from an ultrasonic sensor with a reference value.

JP 2003-107156 A

  In the obstacle detection device described in Patent Document 1 described above, there is a possibility that a road is erroneously detected as an obstacle by detecting a reflected wave reflected on the road. As a result, the detection distance was shortened.

  The present invention has been made in view of the above problems, and an object thereof is to provide an obstacle detection device that maintains a detection distance and reduces false detection.

  An obstacle detection device according to the present invention is attached to a vehicle and transmits a signal wave intermittently to a space around the vehicle, and a reflection reflected by an obstacle among the signal waves transmitted from the transmission unit. A sensor having a receiving unit for receiving a wave, a detecting unit for detecting the presence of the obstacle based on the reflected wave received by the receiving unit, and a waveform of the reflected wave received by the receiving unit. A storage unit, wherein the sensor is arranged such that at least a part of the signal wave transmitted from the transmission unit is reflected by a road and received by the reception unit, and the storage unit is Of the signal waves transmitted from the transmission unit, the waveform of the reflected wave reflected by the road is stored, the waveform of the reflected wave received by the reception unit and the waveform of the reflected wave stored in the storage unit, A calculation unit that generates a differential waveform of , The detection unit, and detecting the presence of the obstacle on the basis of the differential waveform generated by the arithmetic unit.

  In this obstacle detection apparatus, it is preferable that the storage unit stores in advance the waveform of the reflected wave reflected by the road as a reference waveform for comparison with the reflected wave received by the receiving unit.

  Further, in this obstacle detection device, as a reference waveform for comparison with the reflected wave received by the receiving unit, a control unit that stores the waveform of the reflected wave reflected by the road in the storage unit, When the amplitude of the differential waveform generated by the calculation unit is smaller than a reference value, the control unit adds a waveform obtained by adding an average value of the differential waveform to the waveform of the reflected wave reflected by the road as a new reference It is also preferable to store the waveform in the storage unit.

  According to the configuration of the present invention, the waveform of the reflected wave reflected on the road is stored in the storage unit, and the difference waveform between the waveform of the reflected wave received by the receiving unit and the waveform of the reflected wave stored in the storage unit is obtained. Since the presence of an obstacle is detected based on this, there is an effect that false detection can be reduced. In addition, unlike the conventional example, it is not necessary to attenuate the amplitude of the ultrasonic wave transmitted from the ultrasonic sensor, and the detection distance can be maintained.

It is a schematic block diagram of the obstacle detection apparatus which concerns on embodiment of this invention. It is a flowchart explaining operation | movement of the obstruction detection apparatus which concerns on embodiment of this invention. 3A to 3C are explanatory diagrams for explaining the operation of the obstacle detection apparatus according to the embodiment of the present invention. 4A to 4C are signal waveform diagrams of the obstacle detection apparatus according to the embodiment of the present invention. 5A to 5C are explanatory diagrams for explaining another operation of the obstacle detection apparatus according to the embodiment of the present invention. 6A to 6C are other signal waveform diagrams of the obstacle detection apparatus according to the embodiment of the present invention. 7A to 7C are still other signal waveform diagrams of the obstacle detection device according to the embodiment of the present invention. 8A to 8C are still other signal waveform diagrams of the obstacle detection device according to the embodiment of the present invention. 9A to 9C are still other signal waveform diagrams of the obstacle detection apparatus according to the embodiment of the present invention.

  An obstacle detection apparatus according to an embodiment of the present invention will be specifically described with reference to FIGS. However, the configuration described below is merely an example of the present invention, and the present invention is not limited to the following embodiment, and the technical idea according to the present invention is not deviated from other embodiments. Within the range, various changes can be made according to the design and the like.

  FIG. 1 is a schematic block diagram of the obstacle detection apparatus of the present embodiment. The obstacle detection device includes a sensor 1, a detection unit 2, a calculation unit 3, a control unit 4, and a storage unit 5. In the present embodiment, the detection unit 2, the calculation unit 3, and the control unit 4 are realized by the microcomputer 10 and a program that operates the microcomputer 10. In the following description, the microcomputer 10 is abbreviated as the microcomputer 10.

  The sensor 1 is an ultrasonic sensor using ultrasonic waves, for example, and is attached to the front bumper of the vehicle 8 (see FIG. 3A). The sensor 1 includes a transmitter 11 that intermittently transmits ultrasonic waves (signal waves) to the space around the vehicle 8, and an obstacle 9 (see FIG. 3B) of the ultrasonic waves transmitted from the transmitter 11. And a receiving unit 12 for receiving the reflected wave. In the present embodiment, as shown in FIG. 3A, the detection area R1 is set so that the road 100 is included in the detection area R1 of the sensor 1.

  The transmission unit 11 includes an ultrasonic transducer (not shown) such as a piezoelectric element that expands and contracts when a voltage is applied, for example. Then, when a transmission signal is input from the detection unit 2, the transmission unit 11 vibrates the ultrasonic transducer for a predetermined pulse connection time and transmits pulsed ultrasonic waves. In the present embodiment, a drive circuit 6 is connected between the detection unit 2 and the transmission unit 11, and this drive circuit 6 converts the digital transmission signal output from the detection unit 2 into an analog transmission signal. The data is converted and output to the transmission unit 11.

  The receiving unit 12 includes an ultrasonic transducer (not shown) such as a piezoelectric element that generates a voltage when vibration is applied from the outside. And the receiving part 12 will convert the said reflected wave into an electrical signal, and will output an electrical signal toward the calculating part 3, if the reflected wave (ultrasonic wave) by the obstruction 9 is input. In the present embodiment, a detection circuit 7 is connected between the calculation unit 3 and the reception unit 12, and the detection circuit 7 amplifies the electric signal output from the reception unit 12 and shapes the waveform, It outputs to the calculating part 3 as a received signal.

  The storage unit 5 includes, for example, an EEPROM (electrically erasable and programmable read only memory). In this storage unit 5, a waveform of a reflected wave reflected by the road 100 is stored in advance as a reference waveform for generating a differential waveform.

  As described above, the calculation unit 3 is realized by the microcomputer 10 and the program, and the waveform of the reflected wave received by the receiving unit 12 of the sensor 1 and the waveform of the reflected wave (reference waveform) stored in the storage unit 5 are calculated. A differential waveform is generated, and the generated differential waveform is output to the detection unit 2. The procedure for generating the differential waveform will be described later.

  The control unit 4 is realized by the microcomputer 10 and a program similarly to the calculation unit 3, and stores the waveform of the reflected wave reflected on the road 100 in the storage unit 5 as a reference waveform for generating a differential waveform. When the difference waveform generated by the calculation unit 3 is smaller than a predetermined reference value, the control unit 4 adds the difference waveform to the reference waveform (the waveform of the reflected wave reflected by the road 100) stored in the storage unit 5. The waveform to which the average value is added is stored in the storage unit 5 as a new reference waveform. The procedure for updating the reference waveform will be described later.

  The detection unit 2 is realized by the microcomputer 10 and a program similarly to the calculation unit 3, and detects the presence of the obstacle 9 based on the calculation result (difference waveform) of the calculation unit 3. More specifically, the detection unit 2 compares the amplitude (level) of the differential waveform received from the calculation unit 3 with a predetermined reference value, and there is an obstacle 9 when the amplitude of the differential waveform is greater than or equal to the reference value. Judge.

  Moreover, the detection part 2 measures the distance to the obstruction 9, when it is judged that there is the obstruction 9. Specifically, when the detection unit 2 outputs the transmission signal to the transmission unit 11 and receives the reception signal from the reception unit 12, the time from when the transmission signal is output until the reception signal is input. That is, the propagation time required for the ultrasonic wave to reciprocate between the sensor 1 and the obstacle 9 is obtained. And the detection part 2 calculates | requires the distance to the obstruction 9 in the detection area R1 of the sensor 1 based on the said propagation time and sound velocity.

  Furthermore, after obtaining the distance to the obstacle 9, the detection unit 2 determines whether or not the obstacle 9 is abnormally approached based on this distance. For example, when the distance to the obstacle 9 is shorter than a predetermined value, the detection unit 2 determines that the obstacle 9 is abnormally approaching and generates a signal for notifying the obstacle 9 of the abnormal approach. And the said signal produced | generated by the detection part 2 is input into a display apparatus (not shown), and a display apparatus detects that the obstruction 9 is approaching abnormally with the sound, light, etc. with respect to the passenger | crew of the vehicle 8. Inform.

  Next, the operation of the obstacle detection device will be specifically described with reference to the flowchart shown in FIG.

  The detection unit 2 outputs a transmission signal to the transmission unit 11 of the sensor 1 at a predetermined cycle. When a transmission signal is input from the detection unit 2, the transmission unit 11 transmits pulsed ultrasonic waves to the space around the vehicle 8. When an ultrasonic wave transmitted from the transmission unit 11 hits an obstacle 9 existing around the vehicle 8, the ultrasonic wave is reflected by the obstacle 9 and input to the sensor 1.

  When receiving an ultrasonic wave, the receiving unit 12 of the sensor 1 converts the ultrasonic wave into an electric signal and outputs the electric signal to the detection circuit 7. When the electric signal is input from the receiving unit 12, the detection circuit 7 amplifies the electric signal and outputs the received signal obtained by waveform shaping to the arithmetic unit 3 (step ST1).

  When the reception signal is input from the detection circuit 7, the arithmetic unit 3 calculates a difference on the time axis between the reflected wave waveform included in the received signal and the reflected wave waveform (reference waveform) stored in the storage unit 5. Then, a differential waveform is generated (step ST2). Then, the calculation unit 3 outputs the generated differential waveform to the detection unit 2.

  When the differential waveform is input from the calculation unit 3, the detection unit 2 compares the amplitude of the differential waveform with a predetermined reference value. If the amplitude of the differential waveform is greater than or equal to the reference value, the detection unit 2 enters the detection area R <b> 1. It is determined that there is an obstacle 9 (Yes in step ST3). If the amplitude of the differential waveform is smaller than the reference value, the detection unit 2 determines that there is no obstacle 9 in the detection area R1, and returns to the process of step ST2 (No in step ST3).

  Furthermore, when the detection unit 2 determines that there is an obstacle 9 in the process of step ST3, the detection unit 2 measures the distance to the obstacle 9. When the distance to the obstacle 9 is shorter than the predetermined value, the detection unit 2 determines that the obstacle 9 is abnormally approaching, and generates a signal that notifies the obstacle 9 of the abnormal approach. When the signal is input, the display device notifies that the obstacle 9 is abnormally approaching by sound or light (step ST4).

  If the distance to the obstacle 9 is equal to or greater than the predetermined value, the detection unit 2 determines that the obstacle 9 is not abnormally approaching and does not generate the signal (step ST4). Here, in the present embodiment, the above-described processing in the detection unit 2 is a detection algorithm, and a series of operations is completed by executing this detection algorithm (step ST5).

  Next, the procedure in which the calculating part 3 produces | generates a difference waveform is demonstrated, referring FIG. 3A-FIG. 3C and FIG. 4A-FIG. 4C.

  In FIG. 3A, the obstacle 9 does not enter the detection area R <b> 1 of the sensor 1, and only the reflected wave reflected by the road 100 is input to the receiving unit 12. At this time, the waveform of the reflected wave input to the receiving unit 12 is as shown in FIG. 4A. In this embodiment, the reflected wave reflected by the road 100 is used as a reference waveform and stored in the storage unit 5.

  In FIG. 3B, the obstacle 9 is in the detection area R1 of the sensor 1, and the reflected wave reflected by the road 100 and the reflected wave reflected by the obstacle 9 are detected at the same time, and a combined wave of both reflected waves. Is input to the receiving unit 12. At this time, the waveform of the reflected wave input to the receiving unit 12 is as shown in FIG. 4B.

  And the calculating part 3 produces | generates the difference waveform shown to FIG. 4C based on the reference | standard waveform shown to FIG. 4A, and the synthetic | combination waveform shown to FIG. 4B, and outputs it to the detection part 2. FIG. When the amplitude of the differential waveform generated by the calculation unit 3 is greater than or equal to the reference value S1, the detection unit 2 determines that there is an obstacle 9 in the detection area R1 of the sensor 1, that is, in front of the vehicle 8. (See FIG. 3C).

  Next, the case where the reflected wave reflected by the road 100 and the reflected wave reflected by the obstacle 9 are detected at different times will be described with reference to FIGS. 5A to 5C and FIGS. 6A to 6C.

  In FIG. 5A, the obstacle 9 does not enter the detection area R <b> 1 of the sensor 1, and only the reflected wave reflected by the road 100 is input to the receiving unit 12. At this time, the waveform of the reflected wave input to the receiving unit 12 is as shown in FIG. 6A. In this embodiment, the reflected wave reflected by the road 100 is used as a reference waveform and stored in the storage unit 5.

  In FIG. 5B, the obstacle 9 is in the detection area R <b> 1 of the sensor 1, but the reflected wave reflected by the road 100 is detected before the reflected wave reflected by the obstacle 9. Therefore, the waveform of the reflected wave input to the receiving unit 12 is as shown in FIG. 6B.

  And the calculating part 3 produces | generates the difference waveform shown to FIG. 6C based on the reference | standard waveform shown to FIG. 6A, and the synthetic | combination waveform shown to FIG. 6B, and outputs it to the detection part 2. FIG. When the amplitude of the differential waveform generated by the calculation unit 3 is greater than or equal to the reference value S1, the detection unit 2 determines that there is an obstacle 9 in the detection area R1 of the sensor 1, that is, in front of the vehicle 8 (FIG. See 5C).

  As described above, according to the obstacle detection device of the present embodiment, the waveform of the reflected wave reflected by the road 100 is stored in the storage unit 5 as the reference waveform, and the waveform of the reflected wave received by the receiving unit 12 The presence of the obstacle 9 is detected based on the differential waveform of the reflected wave waveform stored in the storage unit 5. This can reduce erroneous detection of the road 100 as the obstacle 9.

  Moreover, since the road 100 may be included in the detection area R1 of the sensor 1, it is not necessary to attenuate the amplitude of the ultrasonic wave transmitted from the ultrasonic sensor as in the conventional example, and the detection distance is maintained. You can also

  By the way, in the above-mentioned embodiment, although the reference waveform memorize | stored in the memory | storage part 5 was made into the fixed value, you may update a reference waveform sequentially as shown below.

  FIG. 7A is a waveform diagram of a reference waveform stored in advance in the storage unit 5, and this reference waveform is stored in the storage unit 5 when the vehicle 8 is shipped from a factory, for example. FIG. 7B is a waveform diagram of a reflected wave input to the receiving unit 12 when the engine of the vehicle 8 is started. 7C is a waveform diagram showing a differential waveform between the reference waveform shown in FIG. 7A and the reflected wave waveform shown in FIG. 7B.

  For example, when the vehicle 8 is placed in a flat parking lot, only the reflected wave reflected on the road is input to the receiving unit 12 when the engine is started, so that the difference from the reference waveform is substantially zero (see FIG. 7C). ). In this case, since the amplitude of the differential waveform generated by the calculation unit 3 is smaller than the reference value S2, the control unit 4 determines the reflected waveform obtained when the engine is started and the reference waveform stored in the storage unit 5. Is stored in the storage unit 5 as a new reference waveform. The above process is repeated every time the engine of the vehicle 8 is started.

  FIG. 8A is a waveform diagram showing the initial value of the reference waveform stored in the storage unit 5 when the vehicle 8 is shipped from the factory, for example. FIG. 8B is a waveform diagram of a reflected wave input to the receiving unit 12 when the engine is started, for example, in a home parking lot. 8C is a waveform diagram showing a differential waveform between the reference waveform shown in FIG. 8A and the reflected wave waveform shown in FIG. 8B.

  For example, when there is a road in front of the home parking lot and the curb provided on this road is included in the detection area R1 of the sensor 1, not only the reflected wave reflected on the road when the engine of the vehicle 8 is started, but also the curb. The reflected wave reflected at is also input to the receiver 12 (see FIG. 8B). Therefore, in this case, it is preferable to set the reference waveform so that the reflected wave reflected by the curb is included.

  The computing unit 3 generates a differential waveform shown in FIG. 8C based on the reference waveform shown in FIG. 8A and the synthesized waveform shown in FIG. 8B. And since the amplitude of the difference waveform which the calculating part 3 produced | generated is smaller than reference value S2, the control part 4 adds the said difference waveform to the reference waveform memorize | stored in the memory | storage part 5 at the time of factory shipment of the vehicle 8. Then, it is stored in the storage unit 5 as a new reference waveform. The control unit 4 also stores the differential waveform generated by the calculation unit 3 in the storage unit 5.

  At the time of the next engine start, a differential waveform is obtained through the same processing. However, the control unit 4 obtains the differential waveform obtained this time (see FIG. 9B) and the previous differential waveform stored in the storage unit 5 (see FIG. 9A). ) And an averaged waveform are generated. And the control part 4 adds the said average waveform to the reference waveform memorize | stored in the memory | storage part 5 at the time of factory shipment of the vehicle 8, produces | generates a new reference waveform, and memorize | stores it in the memory | storage part 5 (refer FIG. 9C). Hereinafter, similarly, the control unit 4 updates the reference waveform stored in the storage unit 5 every time the engine of the vehicle 8 is started.

  As described above, by updating the reference waveform every time the engine of the vehicle 8 is started, it is possible to set the reference waveform according to the usage environment, and as a result, perform obstacle detection according to the usage environment. Can do.

  In the present embodiment, the case where there is one sensor 1 has been described as an example, but the number of sensors 1 is not limited to one, and may be two or more. Further, the mounting position of the sensor 1 is not limited to the front bumper, but may be a rear bumper, a side bumper, or the like. Furthermore, in this embodiment, although the detection part 2, the calculating part 3, and the control part 4 were comprised by the one microcomputer 10, you may comprise separately.

  In the present embodiment, an ultrasonic wave is used as a signal wave for detecting the obstacle 9, but the signal wave is not limited to an ultrasonic wave and may be an electromagnetic wave. Furthermore, in the present embodiment, the memory externally attached to the microcomputer 10 is the storage unit 5, but the memory built in the microcomputer 10 may be the storage unit 5.

  As described above, the obstacle detection device of the present embodiment includes the sensor 1, the detection unit 2, the storage unit 5, and the calculation unit 3. The sensor 1 is attached to the vehicle 8 and receives a reflected wave reflected by the obstacle 9 among the signal wave transmitted from the transmitter 11 and the transmitter 11 that intermittently transmits the signal wave to the space around the vehicle 8. Receiving section 12 is provided. The detection unit 2 detects the presence of the obstacle 9 based on the reflected wave received by the reception unit 12. The storage unit 5 stores the waveform of the reflected wave received by the receiving unit 12. The sensor 1 is arranged such that at least a part of the signal wave transmitted from the transmission unit 11 is reflected by the road 100 and received by the reception unit 12. The storage unit 5 stores the waveform of the reflected wave reflected from the road 100 among the signal waves transmitted from the transmission unit 11. The calculation unit 3 generates a differential waveform between the waveform of the reflected wave received by the receiving unit 12 and the waveform of the reflected wave stored in the storage unit 5. The detection unit 2 detects the presence of the obstacle 9 based on the differential waveform generated by the calculation unit 3.

  Further, like the obstacle detection device of the present embodiment, the storage unit 5 stores in advance the waveform of the reflected wave reflected by the road 100 as a reference waveform for comparison with the reflected wave received by the receiving unit 12. It is preferable.

  In addition, as in the obstacle detection device of the present embodiment, the control unit 4 stores the waveform of the reflected wave reflected on the road 100 in the storage unit 5 as a reference waveform for comparison with the reflected wave received by the receiving unit 12. It is also preferable to have. When the amplitude of the differential waveform generated by the calculation unit 3 is smaller than the reference value S2, the control unit 4 sets a waveform obtained by adding the average value of the differential waveform to the waveform of the reflected wave reflected by the road 100 as a new reference waveform. Store in the storage unit 5.

DESCRIPTION OF SYMBOLS 1 Sensor 2 Detection part 3 Calculation part 5 Storage part 8 Vehicle 9 Obstacle 11 Transmission part 12 Reception part 100 Road

Claims (3)

A transmission unit that is attached to a vehicle and that intermittently transmits a signal wave to a space around the vehicle, and a reception unit that receives a reflected wave reflected from an obstacle among the signal waves transmitted from the transmission unit. A sensor,
A detection unit that detects the presence of the obstacle based on the reflected wave received by the reception unit;
A storage unit for storing the waveform of the reflected wave received by the reception unit,
The sensor is arranged such that at least a part of the signal wave transmitted from the transmitter is reflected by a road and received by the receiver.
The storage unit stores a waveform of a reflected wave reflected on the road among the signal waves transmitted from the transmission unit,
A calculation unit that generates a differential waveform between the waveform of the reflected wave received by the receiving unit and the waveform of the reflected wave stored in the storage unit;
The said detection part detects the presence of the said obstacle based on the said difference waveform produced | generated by the said calculating part, The obstacle detection apparatus characterized by the above-mentioned.   The failure according to claim 1, wherein the storage unit stores in advance the waveform of the reflected wave reflected by the road as a reference waveform for comparison with the reflected wave received by the receiving unit. Object detection device. As a reference waveform for comparing with the reflected wave received by the receiving unit, comprising a control unit for storing the waveform of the reflected wave reflected by the road in the storage unit,
When the amplitude of the differential waveform generated by the arithmetic unit is smaller than a reference value, the control unit newly adds a waveform obtained by adding an average value of the differential waveform to the waveform of the reflected wave reflected by the road. The obstacle detection device according to claim 1, wherein the obstacle detection device stores the reference waveform as a reference waveform.

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