JP5659989B2 - 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 during low-speed running with low road noise. However, a pitch (sounding pitch) or sound that is pronounced according to the running state of the vehicle such as the vehicle speed or the accelerator operation state of the driver By changing the pressure, the “fluctuation” effect of the sound is added. 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, since the pitch and sound pressure do not change while the vehicle speed or accelerator operation is in a constant state, there is a problem that it is not possible to exert the sound “fluctuation” effect that makes it easy for pedestrians to notice the approach of the vehicle there were.

  In view of the above points, the present invention makes it possible for a pedestrian to approach a vehicle more effectively by exerting a sound “fluctuation” effect even when the vehicle running state such as a vehicle speed or an accelerator operation state is constant. It is an object of the present invention to provide a vehicle approach notification device that makes it easier to notice.

  In order to achieve the above object, according to the first aspect of the present invention, the driving state detection signal corresponding to the driving state of the vehicle is input from the driving state acquisition means (1a, 1b) to detect the driving state of the vehicle, Sound generation control means for setting the sound pressure level and pitch of sound generated according to the running state of the vehicle, determination means for determining whether the running state of the vehicle is constant, and the running state of the vehicle are constant If it is determined, the change control means for changing the sound pressure level centered on the sound pressure level set by the sound generation control means and / or changing the sound pitch centered on the pitch set by the sound generation control means It is characterized by having.

  According to such a configuration, when the running state of the vehicle is constant, the sound pressure level can be changed around the set sound pressure level, or the pitch can be changed around the set pitch. . As a result, the “fluctuation” effect of the sound can be exhibited even when the vehicle is in a constant driving state, and the pedestrian can be more easily aware of the approach of the vehicle.

Further, in the first aspect of the present invention, there is provided a change amount calculating means for calculating a change amount of the vehicle speed and / or the accelerator opening with the traveling state as the vehicle speed and / or the accelerator opening, And the sound pressure level is set based on the accelerator opening, and the determination means determines that the vehicle speed and / or the accelerator opening is a constant value based on the amount of change calculated by the change amount calculating means. The change control means changes the sound pressure level and / or the pitch with a predetermined amplitude when the determination means determines that the vehicle speed and / or the accelerator opening is a constant value. It is said.

Thus, for example, the sound pressure level and / or the pitch is set when the sound pressure level is set based on the accelerator opening, the sound pressure level is set based on the accelerator opening, and the vehicle speed and / or the accelerator opening is a constant value. Can be changed with a predetermined amplitude .

The invention according to claim 2 is characterized in that the predetermined amplitude is 1% or more of the sound pressure level and / or the pitch set by the sound generation control means.

  In this way, by changing the pitch and sound pressure level of the generated sound with an amplitude of 1% or more, it becomes possible for a person to reliably detect it.

According to a third aspect of the present invention, there is provided acceleration determination means for determining that the traveling state has been switched to the acceleration state, and the change control means has been determined by the acceleration determination means that the traveling state has been switched to the acceleration state. In addition, the sound pressure level is changed around the sound pressure level set by the sound generation control means, and / or the pitch is changed around the sound set by the sound generation control means.

  Thus, when it is determined that the acceleration state has been switched, the pitch and the sound pressure level are changed. Thereby, it becomes possible to make the pedestrian easily notice the start of acceleration.

In the invention according to claim 4 , the change control means sets the running state to the acceleration state rather than the amplitude that changes the sound pressure level and / or the pitch when the vehicle speed and / or the accelerator opening is determined to be a constant value. When it is determined that the sound has been switched, the sound pressure level and / or the amplitude for changing the pitch is increased.

  As a result, there is a difference between the amplitude when the vehicle speed and the accelerator opening are constant values and the amplitude at the start of acceleration, so that the pedestrian can be noticed accurately.

  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 according to a first embodiment of the present invention. It is the timing chart which showed the relationship between the change of the vehicle speed which showed the action | operation of the vehicle approach notification system concerning 1st Embodiment of this invention, and a pitch (sounding pitch). It is the timing chart which showed the relationship between the change of the vehicle speed which showed the action | operation of the vehicle approach notification system concerning 2nd Embodiment of this invention, and a pitch (sounding pitch).

  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 generates a simulated traveling sound from the speaker 3 that is a sound generator during low-speed traveling with low road noise based on the traveling state detection signals transmitted from the various sensors 1a and 1b. Report the approach of the vehicle to the surrounding pedestrians. 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 constitute vehicle running state acquisition means. As the 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 detection signal indicating the vehicle speed as a vehicle traveling state detection signal, and the accelerator opening sensor 1b outputs a detection signal indicating the accelerator opening as a vehicle traveling state detection signal. For this reason, the vehicle approach notification device 2 inputs a detection signal indicating the vehicle speed and the accelerator opening as a traveling state detection signal, 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 has an arithmetic device corresponding to a memory and control means (not shown), and has a digital analog converter (hereinafter referred to as DAC) 21a and a PWM output device 21b. The memory stores a sound generation control program, sound generation data such as PCM data, a pitch increase amount and a sound pressure level table associated with the vehicle running state indicated by the running state detection signal, and the like. Using this stored content, the microcomputer 21 uses the arithmetic device to calculate the amount of pitch increase corresponding to the vehicle speed indicated by the traveling state detection signal and the sound pressure level corresponding to the accelerator opening, and the calculated amount of pitch increase and Output for setting the sound pressure level is output from the DAC 21a and the PWM output device 21b.

  Specifically, the arithmetic unit provided in the microcomputer 21 includes sound generation control means for calculating a pitch (pitch level) and a sound pressure level corresponding to the vehicle speed and the accelerator opening, and a vehicle speed change amount and an accelerator opening. A change amount calculation means for calculating the change amount, a determination means for determining whether or not the vehicle speed and the accelerator opening are constant values, and a change control means for changing the pitch and the sound pressure level are provided.

  The sound generation control means acquires the vehicle speed and the accelerator opening as physical quantities indicating the running state of the vehicle, and sets the sound pressure level and the pitch based on these. Specifically, the vehicle speed and the accelerator opening are calculated based on detection signals from the vehicle speed sensor 1a and the accelerator opening sensor 1b, and the sound pressure of the sound to be generated is calculated based on the vehicle speed, the accelerator opening and the stored contents of the memory. The pitch is set by setting the level and calculating the pitch up amount and adding it to the reference pitch. Basically, the sound volume increase amount is set so as to increase as the vehicle speed increases, and the sound pressure level is set so as to increase as the accelerator opening increases. In other words, the faster the vehicle approaches the pedestrian, etc., the greater the pitch-up amount, and the greater the driver's operation amount, the higher the sound pressure level, the closer the vehicle approaches the pedestrian. It makes it easy to detect.

  The change amount calculation means calculates the change amount of the physical quantity indicating the running state of the vehicle. Specifically, the change amount calculation means detects the change amount of the vehicle speed or the accelerator detected based on the detection signal from the vehicle speed sensor 1a or the accelerator opening sensor 1b. Calculate the amount of change in opening. For example, since the vehicle speed and the accelerator opening are updated by inputting a detection signal every 20 ms, the amount of change in the vehicle speed and the accelerator opening per unit time (for example, 1 second) is, for example, an average value or maximum value in 1 second. Calculate from the difference between the value and the minimum value.

  The determination means determines whether the calculated vehicle speed change or accelerator opening change is within a predetermined range where the vehicle speed or accelerator opening is assumed to be a constant value, thereby determining the vehicle speed or accelerator opening. It is determined whether or not is a constant value.

  The change control means changes the pitch and sound pressure level of the sound set by the sound generation control means when the determination means determines that the vehicle speed and the accelerator opening are constant values. That is, the pitch is changed when it is determined that the amount of change in the vehicle speed is within the predetermined range, and the sound pressure level is changed when it is determined that the accelerator opening is within the predetermined range.

  With such a configuration, when the vehicle speed and the accelerator opening change, the sound and the sound pressure level corresponding to the vehicle speed and the accelerator opening are set so that the sound “fluctuation” is generated. In addition, sound fluctuations are generated by intentionally changing the sound pressure and the pitch even when the vehicle speed and the accelerator opening are constant values. As the degree of “fluctuation” of the sound generated when the vehicle speed or the accelerator opening is a constant value, for example, the pitch or sound pressure level of the generated sound can be set to an amplitude of 1% or more, and a predetermined cycle. The pitch and sound pressure level are raised and lowered by the amplitude. It has been confirmed that if the pitch or sound pressure level of the generated sound is changed with an amplitude of 1% or more, humans can reliably detect it. For this reason, it is made to change with the amplitude of 1% or more centering on the pitch and sound pressure level set by the sound generation control means.

  When the sound pressure level corresponding to the pitch and the accelerator opening is set in consideration of the pitch increase amount corresponding to the vehicle speed in this way, the PWM output of the set pitch is output from the PWM output device 21b and set. A control signal for setting the sound pressure level is output from the DAC 21a. Specifically, the sampling period corresponding to the set pitch is calculated, the PCM data is read for each sampling period, and the PWM output corresponding to the PCM data is generated, so that the set pitch is obtained. The corresponding PWM output is generated. Further, the voltage generated by the voltage control unit 22 is controlled by outputting a control signal corresponding to the sound pressure level calculated as described above. Specifically, the control signal output from the DAC 21a is changed according to the sound pressure level calculated as described above, and is generated by the voltage control unit 22 when the sound pressure level to be generated increases. The control signal is changed so that the voltage level generated by the voltage control unit 22 decreases as the voltage level increases and the sound pressure level to be generated decreases.

  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. At this time, if the voltage control unit 22 does not adjust the voltage level, the current flowing through the AMP 24 is changed only by the pulse width of the PWM output of the PWM output device 21b. The pulse width becomes too small. However, since the voltage level of the PWM output is made variable by the voltage control unit 22, even when the current flowing through the AMP 24 is small, the pulse width of the PWM output does not need to be extremely reduced.

  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 the relationship between the change in vehicle speed and the pitch (sounding pitch). Although the relationship between the change in vehicle speed and the pitch is shown here, the same timing chart is obtained by changing the accelerator opening.

  The vehicle approach notification system generates a simulated running sound from the speaker 3 which is a sounding body during low speed running with low road noise. First, at time T1, when the vehicle is started from a state where the vehicle on which the vehicle approach notification system is mounted is stopped, road noise is low, so the vehicle approach notification system generates sound. At the start of travel, for example, sound generation is performed from a state in which the pitch is reduced to 50%, and then at time T2, the sound generation pitch is increased to a value that takes into account the pitch increase amount according to the vehicle speed. As the vehicle speed increases, the pitch increases when the vehicle speed increases, and the pitch decreases when the vehicle speed decreases.

  At this time, when the vehicle speed does not change at time T3 and the change amount of the vehicle speed per unit time is within a predetermined range that is assumed to be a constant value, the pitch set at that time is amplified by 1% or more. As a result, even when the vehicle speed is a constant value, it is possible to exhibit the “fluctuation” effect of the sound, and it becomes possible for the pedestrian to become more aware of the approach of the vehicle.

  Thereafter, when the vehicle speed starts to change at time T4, a pitch increase amount corresponding to the vehicle speed is set again, and the pitch is set with the pitch increase amount taken into account. When the vehicle speed reaches a predetermined vehicle speed (for example, 20 km / h) at time T5, it is assumed that the vehicle speed is such that a certain amount of road noise is generated. . Further, when the vehicle speed starts to decrease at time T6 and falls below the predetermined vehicle speed, the pseudo approaching sound is started again by the vehicle approach notification system, and the same operation as described above is performed until the vehicle stops.

  As described above, in the vehicle approach notification system according to the present embodiment, the sound pressure level and the pitch of the sound generated according to the running state of the vehicle are set, and when the running state of the vehicle is constant, the set sound The sound pressure level is changed around the pressure level, or the pitch is changed around the set pitch. Specifically, when the vehicle speed is changing, in addition to setting the pitch increase amount corresponding to the change, the pitch increase amount is also changed by changing the pitch increase amount even when the vehicle speed is not changing. Level). In other words, the pitch is raised or lowered with a predetermined amplitude to generate “fluctuation” of the sound. As a result, even when the vehicle speed is a constant value, it is possible to exhibit the “fluctuation” effect of the sound, and it becomes possible for the pedestrian to become more aware of the approach of the vehicle.

  Similarly, in addition to setting the sound pressure level in response to a change in the accelerator opening, the sound pressure level is also changed when the accelerator opening is not changing. That is, the sound pressure level is raised and lowered with a predetermined amplitude to generate sound “fluctuation”. Thereby, even when the accelerator opening is a constant value, it is possible to exert a “fluctuation” effect of sound, and it becomes possible for a pedestrian to become more aware of the approach of the vehicle.

(Second Embodiment)
A second embodiment of the present invention will be described. In this embodiment, the “fluctuation” effect of the sound is further exhibited with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Only explained.

  In the present embodiment, the microcomputer 21 determines that the vehicle has been switched from the stop state to the acceleration state, and that the vehicle speed and the accelerator opening are determined to be constant values, and then has switched to the acceleration state again. When it is determined that the sound has been switched, the pitch and sound pressure level are changed. This makes it easier for the pedestrian to notice the start of acceleration.

  Specifically, the arithmetic unit provided in the microcomputer 21 is provided with an acceleration determination means for determining that the operation state has been switched to the acceleration state, and the vehicle speed and the accelerator opening are set to constant values. After it is determined that there is, it is determined that the vehicle has switched to the acceleration state again, that is, it has been determined that the vehicle speed and accelerator opening per unit time have increased from a certain value. When it is determined by the acceleration determining means that the acceleration state has been switched, the vehicle speed and the accelerator opening are larger than the amplitude when the vehicle speed and the accelerator opening are constant values centering on the sound pressure level and the pitch set by the sound generation control means. The pitch and the sound pressure level are changed at a predetermined cycle by the amplitude. As a result, there is a difference between the amplitude when the vehicle speed and the accelerator opening are constant values and the amplitude at the start of acceleration, so that the pedestrian can be noticed accurately.

  FIG. 3 is a timing chart showing the relationship between the change in vehicle speed and the pitch (sounding pitch). Although the relationship between the change in vehicle speed and the pitch is shown here, the same timing chart is obtained by changing the accelerator opening.

  As shown in this figure, at time T1, when the vehicle is started from the state where the vehicle equipped with the vehicle approach notification system is stopped, road noise is low and the vehicle approach notification system generates sound. . At the start of travel, for example, sound generation is performed from a state in which the pitch is reduced to 50%, and then at time T2, the sound generation pitch is increased to a value that takes into account the pitch increase amount according to the vehicle speed. At this time, since the vehicle is switched from the stop to the acceleration state, the pitch is made to oscillate at a predetermined cycle centering on the pitch set at that time. As the vehicle speed increases, the pitch increases when the vehicle speed increases, and the pitch decreases when the vehicle speed decreases.

  At this time, when the vehicle speed does not change at time T3 and the change amount of the vehicle speed per unit time is within a predetermined range that is assumed to be a constant value, the pitch set at that time is amplified by 1% or more. As a result, even when the vehicle speed is a constant value, it is possible to exhibit the “fluctuation” effect of the sound, and it becomes possible for the pedestrian to become more aware of the approach of the vehicle.

  Thereafter, when the vehicle speed starts to change at time T4, since the vehicle is switched to the acceleration state, the pitch is made to oscillate at a predetermined cycle centering on the pitch set at that time. The amplitude at this time is made larger than the amplitude when the vehicle speed is a constant value. After that, a pitch increase amount corresponding to the vehicle speed is set again, and the pitch is set with the pitch increase amount taken into account.

  As described above, in the vehicle approach notification system of this embodiment, when it is determined that the vehicle is switched to the acceleration state, the pitch and the sound pressure level are changed at a predetermined cycle. Thereby, it becomes possible to make the pedestrian easily notice the start of acceleration.

(Other embodiments)
In the above-described embodiment, the sound pressure level is changed according to the accelerator opening, and the pitch is changed according to the vehicle speed. However, these are merely examples. For example, both the sound pressure and the sound generation pitch may be changed according to the vehicle speed or the accelerator opening. In this case, as the vehicle speed or accelerator opening increases, the sound pressure increase amount and the pitch increase amount can be increased.

  In the microcomputer 21, the DAC 21a is used to output the control signal, and the control of the voltage control unit 22 is performed by generating a control signal for changing the sound pressure from the DAC 21a. You may make it perform voltage control of the voltage control part 22 using a controller. When using the PWM controller and changing the sound pressure according to the vehicle speed or the accelerator opening, for example, changing the on / off duty ratio of the PWM output according to the vehicle speed or the accelerator opening, and changing the sampling period of the PWM output Change it.

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 (4)

In the vehicle approach notification device for reporting the approach of the vehicle by controlling the sound pressure level and / or pitch of the sound from the sound generator (3) mounted on the vehicle,
A sound pressure level of sound generated by detecting a traveling state of the vehicle by inputting a traveling state detection signal corresponding to the traveling state of the vehicle from the traveling state acquisition means (1a, 1b), and generating according to the traveling state of the vehicle. And sound generation control means for setting the pitch,
Determining means for determining whether or not the running state of the vehicle is constant;
If it is determined that the running state of the vehicle is constant, the sound pressure level is changed around the sound pressure level set by the sound generation control means, and / or the sound pressure control means sets the sound pressure level. Change control means for changing the pitch around the pitch , and
A change amount calculating means for calculating a change amount of the vehicle speed and / or the accelerator opening, with the traveling state as a vehicle speed and / or an accelerator opening;
The sound generation control means sets the sound pitch based on the vehicle speed and sets the sound pressure level based on the accelerator opening,
The determining means determines whether the vehicle speed and / or the accelerator opening is a constant value based on the change amount calculated by the change amount calculating means,
The change control means changes the sound pressure level and / or the pitch with a predetermined amplitude when the determination means determines that the vehicle speed and / or the accelerator opening is a constant value. Vehicle approach notification device. The vehicle approach notification device according to claim 1 , wherein the predetermined amplitude is 1% or more of the sound pressure level and / or the pitch set by the sound generation control means. Accelerating determination means for determining that the traveling state has been switched to an accelerating state;
The change control means changes the sound pressure level around the sound pressure level set by the sound generation control means even when the acceleration determination means determines that the running state is switched to the acceleration state. , and / or, the vehicle approach warning system according to claim 1 or 2, characterized in that varying the extent the sound around the pitch set by the sound generation control means. The change control means determines that the traveling state is switched to an acceleration state based on an amplitude that changes the sound pressure level and / or the pitch when the vehicle speed and / or the accelerator opening is determined to be a constant value. The vehicle approach notification device according to claim 3 , wherein an amplitude for changing the sound pressure level and / or the pitch when the sound pressure is applied is increased.

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