JP5678877B2 - Vehicle approach notification device - Google Patents

Description

  The present invention relates to a vehicle approach notification device that notifies the surroundings that a vehicle is approaching by generating sound from the vehicle.

  In recent years, electric vehicles (EV cars), hybrid cars (HV cars), etc. have structurally low noise, and it is difficult for pedestrians to notice the approach of these vehicles. A vehicle approach notification device that generates a simulated running sound is being mounted to increase the degree of recognition that the vehicle is nearby (see, for example, Patent Document 1). In this vehicle approach notification device, as a sound generation method, data such as PCM (Pulse Code Modulation) stored in the memory of a microcomputer, that is, a voice code converted into a data code, is encoded for each sampling period. A method is used in which sound is generated by being set in a / A converter or PWM output device. Moreover, in the vehicle approach notification device, a pseudo running sound is generated at low speed traveling with low road noise. However, when the vehicle is in an accelerated state, the approaching of the vehicle becomes faster and the risk to pedestrians increases. In addition, the “fluctuation” effect of the sound is added by increasing the pitch (sounding pitch) according to the increase in the vehicle speed or by changing the sound pressure according to the accelerator operation state of the driver. This makes it easier for the pedestrian to notice the approach of the vehicle, and also makes the running state of the vehicle recall.

JP 2009-35195 A

  However, when the sound pressure is controlled in accordance with the accelerator opening for the purpose of recalling the acceleration state of the vehicle, the sound pressure will rapidly increase when the driver depresses the accelerator pedal suddenly. Become. For this reason, there has been a contradiction that pedestrians are surprised more than necessary or that ambient noise increases.

  In view of the above-mentioned points, the present invention accelerates a vehicle in the surroundings without surprised a pedestrian more than necessary or increasing ambient noise when changing the sound pressure according to the accelerator opening. An object of the present invention is to provide a vehicle approach notification device capable of notifying a state.

  In order to achieve the above object, according to the first aspect of the present invention, the sound output data is read from the memory means storing the sound output data, and the sound output generator (21b) for generating the sound output of the sound output data, and the sound output generation A voltage control unit (22) for changing the voltage value of the output waveform of the sound output of the sound output data output by the unit (21b), and a sound generator mounted on the vehicle with a current corresponding to the output of the voltage control unit (22) 3) In the vehicle approach notification device that includes an amplifier (24) that causes the sounding body to generate a vehicle approach notification sound by flowing to 3), and that reports the approach of the vehicle by sounding the vehicle approach notification sound. An accelerator operation amount acquisition means for acquiring an operation amount; a change amount calculation means for calculating a temporal change amount of the accelerator operation amount from the accelerator operation amount acquired by the accelerator operation amount acquisition means; A sounding output generating unit (21b) is generated by the sounding control means for setting the envelope frequency of the vehicle approach notification sound based on the time change amount of the accelerator operation amount calculated by the conversion amount calculating means, and the voltage control unit (22). It is characterized by having change control means for changing the voltage level of the output waveform of the sound output of the sound output data to be output according to the envelope frequency.

  In this way, by setting the envelope frequency of the vehicle approach notification sound according to the time change speed of the accelerator operation amount, and changing the voltage value of the output waveform of the sound output accordingly, the sound output according to the envelope frequency The voltage level of the output waveform is changed. For this reason, the acceleration state of the vehicle by the driver can be recalled relatively by the change of the envelope frequency. The voltage level at this time is not increased in proportion to the accelerator opening, but is changed in accordance with the change in the envelope frequency, and the change in the envelope level is represented by the change in the voltage level. For this reason, the acceleration state of the vehicle can be notified to the surroundings without surprised the pedestrian more than necessary or without increasing the ambient noise.

Specifically, in the first aspect of the invention, the sound generation control means increases the envelope frequency when the temporal change amount of the accelerator operation amount indicates that the accelerator operation is performed on the vehicle acceleration side, when set to a minimum value envelope frequency to represent that the accelerator operation is performed on the side of the accelerator operation amount for decelerating the 0 or vehicle. Thereby, the envelope frequency of the vehicle approach notification sound can be set according to the temporal change speed of the accelerator operation amount, and the voltage level of the output waveform of the sound output can be changed accordingly.

In the invention according to claim 2 , the acquisition means also acquires the vehicle speed, and the sound generation control means sets a reproduction speed of the sound output based on the vehicle speed acquired by the acquisition means, and for each sampling period corresponding to the reproduction speed. The sound output data is read by the sound output generator.

  In this way, since the playback speed of the approach notification sound is changed according to the vehicle speed, the higher the speed at which the vehicle approaches the pedestrian or the like, the higher the pitch, and the pedestrian due to the change in the pitch. The speed at which the vehicle approaches can be recalled relatively.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

1 is a block diagram of a vehicle approach notification system including a vehicle approach notification device according to a first embodiment of the present invention. It is the timing chart which showed the waveform of the sound sounded as the change of a vehicle speed and the change of an accelerator opening degree. It is the timing chart which showed the waveform of the sound sounded as the change of the vehicle speed in the case of controlling sound pressure according to the accelerator opening, and the change of accelerator opening.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
FIG. 1 is a block diagram of a vehicle approach notification system including a vehicle approach notification device according to the present embodiment. With reference to this figure, the vehicle approach notification system including the vehicle approach notification apparatus according to the present embodiment will be described.

  As shown in FIG. 1, the vehicle approach notification system includes various sensors 1 a and 1 b, a vehicle approach notification device 2, and a speaker 3. In the vehicle approach notification system, the vehicle approach notification device 2 reports vehicle approach such as simulated traveling sound from the speaker 3 which is a sounding body during low-speed traveling with low road noise based on the traveling state detection signals transmitted from the various sensors 1a and 1b. By sounding, it notifies the nearby pedestrians of the approach of the vehicle. Here, the vehicle approach notification device 2 is separated from the speaker 3, but the speaker 3 may be integrated with the vehicle approach notification device 2.

  The various sensors 1a and 1b detect the traveling state of the vehicle. As various sensors 1a and 1b, a vehicle speed sensor 1a and an accelerator opening sensor 1b are provided. The vehicle speed sensor 1a outputs a vehicle speed detection signal of the vehicle, and the accelerator opening sensor 1b outputs an accelerator opening detection signal indicating the accelerator opening as an accelerator operation amount indicating the acceleration state of the vehicle. The vehicle approach notification device 2 inputs detection signals indicating the vehicle speed and the accelerator opening, and controls sound generation according to the traveling state of the vehicle such as the vehicle speed and the accelerator opening.

  The vehicle approach notification device 2 includes a microcomputer 21, a voltage control unit 22, a low-pass filter (hereinafter referred to as LPF) 23, and a power amplifier (hereinafter referred to as AMP) 24.

  The microcomputer 21 includes a memory corresponding to memory means (not shown) and an arithmetic device corresponding to control means, and a digital analog converter (hereinafter referred to as DAC) 21a and a PWM output device 21b. . In the memory, sound generation data such as a sound generation control program and PCM data, an envelope frequency (for example, about 0.125 to 5 Hz) associated with the running state of the vehicle indicated by various detection signals, a playback speed of the sound waveform, that is, a pitch A table of levels (for example, 100 to 150%) is stored. Using the stored contents, the microcomputer 21 uses a calculation device to calculate the reproduction speed (sound level) corresponding to the vehicle speed indicated by the vehicle speed detection signal and the envelope frequency corresponding to the accelerator opening indicated by the accelerator opening detection signal. A sound output is generated from the PWM output device 21b at the calculated reproduction speed, and an output for setting the calculated envelope frequency is generated from the DAC 21a.

  Specifically, the calculation device provided in the microcomputer 21 includes an acquisition means for acquiring the vehicle speed and the accelerator opening, a change amount calculating means for calculating a temporal change amount (slope) of the accelerator opening, a vehicle speed and an accelerator opening. A sound generation control means for calculating a reproduction speed and an envelope frequency corresponding to the degree, and a change control means for changing the pitch and sound pressure level of the sound to be generated based on the calculated reproduction speed and the envelope frequency are provided.

  The acquisition means inputs a vehicle speed detection signal from the vehicle speed sensor 1a and an accelerator opening detection signal from the accelerator opening sensor 1b, and acquires the vehicle speed and the accelerator opening based on these signals. The change amount calculation means calculates the accelerator opening change amount (tilt) by differentiating the accelerator opening obtained by the acquisition means with respect to time. For example, since the accelerator opening is obtained from the accelerator opening detection signal at each sampling period, the time differential value of the accelerator opening is obtained by calculating the difference between the previous accelerator opening and the current accelerator opening. be able to.

  In the sound generation control means, it is determined whether or not to sound based on the vehicle speed and change amount calculation means acquired by the acquisition means or the time variation of the accelerator opening, and the playback speed and envelope frequency during sound generation are set. I do. Specifically, when the vehicle speed is less than a predetermined speed (for example, 20 km / h), the sound to be generated is reproduced based on the calculated vehicle speed, the time variation of the accelerator opening, and the stored contents of the memory in order to produce sound. Calculate velocity and envelope frequency. For example, if the memory stores a table in which the vehicle speed and the reproduction speed are associated with each other, or a table in which the amount of change in the accelerator opening with time and the envelope frequency are associated with each other, the vehicle speed and the accelerator are used. The playback speed and envelope frequency corresponding to the amount of change in the opening over time are selected. An arithmetic expression can be stored in place of the table, and in that case, the temporal change in the vehicle speed and the accelerator opening can be calculated by substituting the temporal change in the vehicle speed and the accelerator opening into the arithmetic expression. Calculate the corresponding playback speed and envelope frequency.

  Basically, the playback speed is set so that the playback speed increases, that is, the pitch level increases as the vehicle speed increases. As for the envelope frequency, when the time variation (slope) of the accelerator opening is positive, the envelope frequency increases as the time variation increases, and when the time variation is 0 or a negative value. Is set so that the envelope frequency becomes a minimum value (for example, 0.125 Hz).

  The change control means reads the sound generation data stored in the memory at every sampling period corresponding to the playback speed calculated by the sound generation control means, and sets the sound pressure level of the sound to be generated based on the calculated envelope frequency To do. That is, by reading out the sound generation data at each sampling period corresponding to the calculated reproduction speed, it is possible to obtain a pitch according to the reproduction speed, and the output waveform of the sound output based on the calculated envelope frequency. By setting the voltage level, the sound pressure level can be adjusted according to the envelope frequency. As a result, “fluctuation” of the sound is generated.

  When the sound generation data is read at the reproduction speed corresponding to the vehicle speed in this way, the PWM output corresponding to the read sound generation data is output from the PWM output device 21b and the envelope frequency corresponding to the temporal change amount of the accelerator opening. The DAC 21a outputs a control signal for setting the voltage level of the output waveform of the sound output set based on the above. Specifically, the control signal output from the DAC 21a is changed according to the voltage level calculated as described above. When the voltage level of the output waveform of the sound output increases, the voltage control unit 22 The control signal is changed so that the voltage level generated by the voltage control unit 22 decreases as the voltage level (voltage value) to be generated increases and the voltage level of the output waveform of the sound output decreases. Thereby, the voltage generated by the voltage control unit 22 is controlled.

  The voltage control unit 22 changes the voltage level of the PWM output based on the control signal transmitted from the DAC 21a, and changes the voltage level of the PWM output to the voltage level indicated by the control signal. Therefore, for example, the lower the sound pressure level that is generated, the lower the voltage level of the PWM output, and the voltage control unit 22 outputs the voltage level.

  The LPF 23 corresponds to filter means, and removes high frequency noise components and generates an output corresponding to the output of the PWM output device 21 b transmitted via the voltage control unit 22. For example, the LPF 23 stores a voltage corresponding to the output of the voltage control unit 22 in a built-in capacitor and outputs it to the AMP 24.

  The AMP 24 supplies a current corresponding to the output of the LPF 23 to the speaker 3 based on voltage application from a constant voltage source (not shown). The sound pressure generated by the speaker 3 is determined according to the magnitude (amplitude) of the current supplied from the AMP 24, and the magnitude of the current supplied from the AMP 24 is determined by the output waveform of the LPF 23 corresponding to the PWM output. For this reason, the current flowing through the AMP 24 can be changed based on the adjustment of the voltage level in the voltage control unit 22.

  With the configuration as described above, a vehicle approach notification system including the vehicle approach notification device according to the present embodiment is configured. The vehicle approach notification system configured as described above operates as follows. The operation of this vehicle approach notification system will be described with reference to FIG.

  FIG. 2 is a timing chart showing a sound waveform that sounds as a change in vehicle speed and a change in accelerator opening. FIG. 3 is a comparative example, and is a timing chart showing a sound waveform that is pronounced as a change in vehicle speed and a change in accelerator opening when the sound pressure is controlled in accordance with the accelerator opening.

  First, as shown in FIG. 2, since the playback speed is increased as the vehicle speed increases, the playback speed of the sound data increases, and the amplitude period of the sound waveform shown in the figure becomes shorter. The waveform is expressed in a dense state. That is, with the increase in the vehicle speed, the reproduction speed of the sound production data increases and the pitch is increased.

  In addition, as shown in FIG. 2, the envelope frequency is also increased during a period in which the time change rate of the accelerator opening is large, so that the envelope amplitude period is shortened (period indicated by the envelope frequency UP in the figure). . On the contrary, since the envelope frequency is set to the minimum value during the period when the time change rate of the accelerator opening is small, the amplitude period of the envelope becomes long (period indicated by the envelope frequency MIN in the figure).

  In this way, the playback speed of the vehicle approach notification sound is changed according to the vehicle speed, so that the higher the speed at which the vehicle approaches the pedestrian or the like, the higher the pitch, so that the walking by the change in the pitch. The speed at which the vehicle approaches the person can be recalled relatively. In addition, since the envelope frequency of the approach notification sound is set according to the time change rate of the accelerator opening, and the voltage level of the output waveform of the sound output is changed accordingly, the accelerator operation by the driver, that is, the vehicle The acceleration operation state can be recalled relatively by changing the envelope frequency.

  As explained above, in the vehicle approach notification device according to the present embodiment, the envelope frequency of the approach notification sound is set according to the temporal change speed of the accelerator opening, and the voltage level of the output waveform of the sound output is set accordingly. It is changing. For this reason, the acceleration state of the vehicle by the driver can be recalled relatively by the change of the envelope frequency.

  In this way, the envelope frequency of the approach notification sound is changed according to the temporal change speed of the accelerator opening, and the voltage level of the output waveform of the sound output is set according to the change of the envelope frequency. The voltage level at this time is not increased in proportion to the accelerator opening, but is changed within a predetermined range according to the change in the envelope frequency, and the change in the voltage level represents the change in the envelope frequency. It has become only. For this reason, the acceleration state of the vehicle can be notified to the surroundings without surprised the pedestrian more than necessary or without increasing the ambient noise.

  The envelope frequency is changed, for example, in the range of 0.125 to 5 Hz. By using such a frequency range, the envelope of the sound emitted by a person can be set to a slow frequency that is easy to recognize or image. It is possible to make the pedestrian recognize the change in the envelope frequency.

(Other embodiments)
In the above embodiment, the microcomputer 21 uses the DAC 21a to output a control signal, and generates a control signal for changing the sound pressure from the DAC 21a, thereby performing voltage control of the voltage control unit 22. However, the voltage control of the voltage control unit 22 may be performed using a PWM controller. When using the PWM controller, when changing the voltage level of the output waveform of the sound output in accordance with the amount of time change of the accelerator opening, for example, the duty ratio of on / off of the PWM output is changed according to the accelerator opening And the sampling period of the PWM output may be changed.

  In addition, the accelerator opening is detected as an accelerator operation amount indicating the acceleration state of the vehicle. However, a physical amount indicating another accelerator operation amount, for example, an accelerator pedal depression amount is detected, and the accelerator operation amount is detected by the vehicle. Increase the envelope frequency to indicate that the accelerator operation has been performed on the acceleration side, and set the envelope frequency to the lowest value to indicate that the operation amount is 0 or that the accelerator operation has been performed on the vehicle deceleration side good.

DESCRIPTION OF SYMBOLS 1a Vehicle speed sensor 1b Accelerator opening sensor 2 Vehicle approach notification apparatus 3 Speaker 21 Microcomputer 21a DAC
21b PWM output device 22 Voltage control unit 23 LPF
24 AMP

Claims (2)

A sound output generator (21b) that reads out the sound data from the memory means storing the sound data and generates a sound output of the sound data;
A voltage control unit (22) for changing a voltage value of an output waveform of the sound output of the sound output data output by the sound output generator;
An amplifier (24) for causing the sounding body to generate a vehicle approach notification sound by causing a current corresponding to the output of the voltage control section (22) to flow through the sounding body (3) mounted on the vehicle; In the vehicle approach notification device that reports the approach of the vehicle by sounding the vehicle approach notification sound,
An accelerator operation amount acquisition means for acquiring an accelerator operation amount;
A change amount calculating means for calculating a temporal change amount of the accelerator operation amount from the accelerator operation amount acquired by the accelerator operation amount acquiring means;
Sound generation control means for setting an envelope frequency of the vehicle approach notification sound based on a temporal change amount of the accelerator operation amount calculated by the change amount calculation means;
By the voltage control unit, it possesses a change control means for changing in accordance with the envelope frequency voltage value of the output waveform of the sound output of the sound data to which the sound output generating unit outputs,
The sound generation control means increases the envelope frequency when the time change amount of the accelerator operation amount indicates that the accelerator operation is performed on the side of accelerating the vehicle, and the accelerator operation amount is 0 or the side of decelerating the vehicle A vehicle approach notification device characterized in that the envelope frequency is set to a minimum value when it represents that an accelerator operation has been performed . A sound output generator (21b) that reads out the sound data from the memory means storing the sound data and generates a sound output of the sound data;
A voltage control unit (22) for changing a voltage value of an output waveform of the sound output of the sound output data output by the sound output generator;
An amplifier (24) for causing the sounding body to generate a vehicle approach notification sound by causing a current corresponding to the output of the voltage control section (22) to flow through the sounding body (3) mounted on the vehicle; In the vehicle approach notification device that reports the approach of the vehicle by sounding the vehicle approach notification sound,
An accelerator operation amount acquisition means for acquiring an accelerator operation amount;
A change amount calculating means for calculating a temporal change amount of the accelerator operation amount from the accelerator operation amount acquired by the accelerator operation amount acquiring means;
Sound generation control means for setting an envelope frequency of the vehicle approach notification sound based on a temporal change amount of the accelerator operation amount calculated by the change amount calculation means;
Change control means for changing the voltage value of the output waveform of the sound output of the sound output data output from the sound output generator by the voltage control unit according to an envelope frequency;
The acquisition means also acquires the vehicle speed,
The sound generation control unit sets the reproduction speed of the sound output based on the vehicle speed acquired by the acquisition unit, and reads out the sound generation data by the sound output generation unit at each sampling period corresponding to the reproduction speed. car both approach warning device characterized by causing.

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