Patent Application
20130063258
The present invention relates to an electric moving body alarm sound control device that is equipped with an alarm sound generation mechanism for telling its approaching to nearby pedestrians etc., in electric moving bodies, such as hybrid vehicles and electric vehicles, excellent in quietness.
Following the practical development of electric bicycles and carts in recent years, transportation means serving as various kinds of moving bodies, such as electric motorcycles and electric vehicles, have been powered by electricity. Specifically, as the replacement of motor vehicles powered by internal combustion engines, there have been developed one after another vehicles such as hybrid vehicles powered by both gasoline engines and electric motors, electric vehicles powered by electric motors driven by onboard batteries that are recharged by power sources for household use and battery chargers installed at gas stations, power supply stations, etc., and fuel cell vehicles that run while generating electricity by fuel cells using hydrogen and the like as the fuel. Some of those hybrid vehicles and electric vehicles have already been put into practical use and begun becoming widespread.
Since gasoline vehicles, diesel vehicles, etc. powered by the conventional internal combustion engines generate not only engine exhaust sound their power sources emit but also road noise and the like in running, pedestrians going around town streets, cyclists, etc. can recognize those vehicles approaching by their engine and exhaust sound and the like. However, when running at low speed, the hybrid vehicles do not run powered by the combustion engines, but go into a running mode powered by the electric motors; therefore, engine and exhaust sound and the like are not generated, and furthermore, as to the electric vehicles and fuel cell vehicles, they even run driven by the electric motors over the whole operation range, which has made both vehicles particularly quiet electric moving bodies. However, pedestrians, cyclists, etc. who are in the vicinity of such quiet electric moving bodies as above cannot recognize by sound the approaching of the electric moving bodies, such as hybrid vehicles, electric vehicles and fuel cell vehicles, running driven by the electric motors that generate little sound and excel in quietness, which therefore might cause occurrence of accidental contact of the pedestrians etc. with those electric moving bodies excellent in quietness.
Therefore, in order to aim at solving the foregoing problem in that quietness, which should be the advantage inherent to the hybrid vehicles, electric vehicles and fuel cell vehicles, sometimes become harmful, there have been proposed various systems, other than klaxons mounted on conventional vehicles and operating following drivers' intention, that operate independently of the drivers' intention and give an alarm about the presence of the vehicles' own.
For example, a technology has been disclosed in Patent Document 1, in which a vehicle includes a running ambience determination means that determines a running ambience surrounding the vehicle, and determines, as the running ambience, a running area, running time of the day, brightness around the running area, and the volume of sound outside the vehicle when running, whereby the vehicle chooses an alarming means by sound depending on the running ambience, or when determining that an alarm means by sound is ineffective, the vehicle does not choose the alarming means by sound, but chooses an alarming means by light, for example, to give an alarm about the presence of its own.
Moreover, an alarm system has been disclosed in Patent Document 2, which includes a determination means that determines timing at which a vehicle gives an alarm about the presence of the vehicle's own to the vicinity of the vehicle, and an output means that emits outside the vehicle (particularly forward of the vehicle) a predetermined acoustic signal on which predetermined noise is superimposed (vehicle-approach-telling sound for telling vehicle's approaching) so as to cause a stochastic resonance phenomenon, when the determination means determines that it is the timing of giving the alarm about the presence of its own to the vicinity thereof.
In addition, a technology and others have been disclosed in Patent Document 3, in which an alarm system includes an object detection unit and vehicle speed detection unit, and when an object is detected, varies an angular range of sound emitted from an alarm unit that emits sound forward depending on the detected vehicle speed, and in which sound by a musical box is utilized as the alarm sound.
Furthermore, in Patent Document 4 are disclosed a technology in which an alarm system includes an object sensor that detects an object in the vicinity of a vehicle, and when an object is detected, takes control of an electric drive system of the vehicle so that sound generated by a drive source constituting the electric drive system becomes alarm sound, and another technology in which an alarm system, for the purpose of controlling the volume of generation sound, takes controls of such as increasing torque ripple of the motor, setting audible range of the frequency of a PWM carrier signal, continuously varying the frequency of the PWM carrier signal, and increasing rotation speed of a pump for discharging coolant to cool heat-generating parts, whereby pedestrians etc. in the vicinity are enabled to easily recognize the alarm sound.
Alarm systems to enable pedestrians etc. to recognize the presence of an electric moving body are configured as described above, and there have been proposed a variety of technologies to take control of alarm sound and the like depending on the ambience surrounding the electric moving body or the status of its own; in particular, however, in taking control of the alarm sound, the alarm systems do not take control in such a way as to generate suitable alarm sound by detecting the noise level the electric moving body actually generates; therefore, the alarm sound has been likely to be emitted more than necessary, or less than necessary.
The present invention has been made to aim at solving the foregoing problem, and providing an electric moving body alarm sound control device in which the volume level of alarm sound is controlled depending on the noise level the electric moving body actually generates, so that the alarm sound is not likely to be generated more than necessary nor less than necessary.
An electric moving body alarm sound control device according to the present invention comprises an electric moving body noise detection unit that detects noise an electric moving body generates by itself; an electric moving body noise level comparison determination unit that determines the noise level the electric moving body generates, based on the detection signal detected by the electric moving body noise detection unit; and an alarm sound volume level control unit that takes control of the volume level of alarm sound a sound-emitting unit emits, based on the determination result by the electric moving body noise level comparison determination unit.
According to the present invention, an electric moving body alarm sound control device can be provided, in which noise the electric moving body generates by itself is detected, and the volume of alarm sound is controlled based on the detected noise level; therefore, the alarm sound is not likely to be generated more than necessary nor less than necessary.
The method of controlling is as follows: for example, when the electric moving body noise level comparison determination unit 2 determines that the noise level generated by the electric moving body itself is lower than a predetermined level, the gain of the alarm sound amplifier 5 is controlled in such a way that the noise level generated by the whole electric moving body, in which the alarm sound the sound-emitting unit 6 emits is added to the noise the electric moving body generates by itself, exceeds the predetermined level.
Next, a configurational example of the electric moving body noise detection unit 1 will be described. First of all, as shown in
The detection signal detected by the electric moving body lower portion noise detection unit 12 is for the most part noise the electric moving body generates by itself, and includes in part noise in the ambience surrounding the electric moving body. Moreover, the detection signal detected by the electric moving body upper portion noise detection unit 11 is for the most part the noise in the ambience surrounding the electric moving body, and includes in part the noise the electric moving body generates by itself. Thus as shown in
By configuring as described above, when the volume level of noise the electric moving body generates by itself is lower than the predetermined volume level, it is presumed that pedestrians etc. in the vicinity thereof are likely to miss the moving body; by adding the alarm sound, the overall sound volume the electric moving body generates is increased to greater than the predetermined volume, so that pedestrians etc. in the vicinity are enabled to recognize the presence of the electric moving body. Meanwhile, when the volume of noise the electric moving body generates by itself exceeds the predetermined volume, it is presumed the pedestrians etc. in the vicinity can recognize the presence of the electric moving body only by the noise the electric moving body generates by itself, and generation of the alarm sound is stopped, so that the alarm sound can be prevented from causing adverse effect on the ambient noise.
The configuration of the electric moving body noise detection unit 1 is, for example, the one shown in
By configuring as described above, when sound volume difference between the volume of noise the electric moving body generates and the volume of noise generated in the ambience surrounding the electric moving body is less than a first predetermined volume, it is presumed that pedestrians etc. in the vicinity thereof are likely to miss the presence of the electric moving body. By adding the alarm sound, the sound volume difference between the volume of noise the electric moving body generates as a whole and volume of noise generated in the ambience surrounding the electric moving body is increased to greater than the predetermined volume, thereby enabling pedestrians etc. in the vicinity to recognize the presence of the electric moving body.
Moreover, when the sound volume difference between the volume of noise the electric moving body generates and volume of noise generated in the ambience surrounding the electric moving body is greater than the first predetermined volume, it is presumed that pedestrians etc. in the vicinity can recognize the presence of the electric moving body, so generation of the alarm sound is stopped, so that the alarm sound is prevented from causing adverse effect on the ambient noise.
Furthermore, when the sound volume difference between the volume of noise the electric moving body generates and volume of noise generated in the ambience surrounding the electric moving body is greater than a second predetermined volume, it is presumed that pedestrians etc. in the vicinity may feel the noise the electric moving body generates too noisy. Alarm sound in reversed phase is generated to cancel out the noise the electric moving body generates, so that the noise the electric moving body generates is prevented from causing adverse effect on the ambient noise.
When the alarm sound switching unit 40 is not provided, the alarm sound the sound-emitting unit 6 emits is mixed into both the electric moving body lower portion noise detection unit 12 and electric moving body upper portion noise detection unit 11; therefore, the noise the electric moving body generates by itself and the ambient noise need to be separated from the alarm sound and then computed. According to this Embodiment 3, since the alarm sound switching unit 40 is provided to control the generation of the alarm sound to stop only during the determination, the alarm sound is not mixed into signals detected by the electric moving body lower portion noise detection unit 12 and electric moving body upper portion noise detection unit 11, so that the signals can include only the noise the electric moving body generates by itself and ambient generation noise; therefore, the alarm sound does not need to be separated and then computed, whereby the configuration of the electric moving body noise level comparison determination unit 2 can be simplified.
By configuring as described above, the electric moving body generation noise level the electric moving body generates by itself can be computed more accurately.
By configuring as described above, the electric moving body generation noise level the electric moving body generates by itself and ambient generation noise level can be computed accurately, even when the vehicle interior noise level is high.
Moreover, still more noise detectors may be provided; noise the electric moving body generates by itself or noise generated in the ambience surrounding the electric moving body is computed by using detection signals detected by the plurality of noise detectors installed at different positions, whereby the noise the electric moving body generates by itself and noise generated in the ambience surrounding the electric moving body can be accurately detected with a simple configuration.
The input I includes the sound i and sound j with those mixed together; the sound i is dominant input and equation I=I+a*j. In addition, the input J includes the sound i and sound j with those mixed together; the sound j is dominant input and equation J=b*i+j is input, where a and b are predetermined constants in a fixed spatial field depending on microphone installation positions.
In order to derive only j from those two inputs, I and J
j=(J−b*I)/(1+a*b)
Therefore
j∝J−α*I
Then α is obtained, control takes place at a level control 104, and j is derived as an output 105.
Similarly, in order to derive only i
i=(I−a*J)/(1+a*b)
Therefore
i′I−β*J
Then β is obtained, control takes place at the level control 104, and i is derived as the output 105.
By configuring as described above, only the required sound can be derived from a mixture of multiple sorts of sound at the inputs. Using multiple stages of the above enables multiple inputs to be dealt with.
For example, as shown in Embodiment 5, when there are three inputs, I, J and K, as the input signals, that is, the detection signal detected by the electric moving body upper portion noise detection unit 11, the detection signal detected by electric moving body lower portion noise detection unit 12, and the detection signal detected by the vehicle interior noise detection unit 17, those are expressed by using predetermined constants of a to f in the fixed spatial field depending on the microphone installation positions as follows:
I=i+a*j+c*k
J=b*i+j+d*k
K=e*i+f*j+k
In order to derive only i from the three inputs, I, J and K
i=[(1−d*f)*I−(1−c*f)*J−−{c*(1−d*f)−d*(1−c*f)}*K]/{(1−c*e)−(1−c*f)(b−d*e)
Therefore
i∝I−α*J−γ*K
Then gains α and γ are obtained, and control takes place.
Next, in Tables 1 to 4 are shown comparison states at the electric moving body noise level comparison determination unit 2 and control states of the comparison results, when the alarm sound is controlled by using the noise the electric moving body generates by itself and ambient generation noise as derived above.
Tables 1 and 2 show examples, in which, as explained in Embodiment 1, determination is made at the electric moving body noise level comparison determination unit 2, by using the noise that is generated by the electric moving body itself and detected by the electric moving body noise detection unit 1. As shown in Tables 1 and 2, by using the volume of noise the electric moving body generates by itself, X, an electric moving body generation specified volume, which is a preset specified value, RX, a preset alarm sound volume, S, and an attenuation adjusting factor, Adj1, in a space from the alarm sound generation speaker, which is the sound-emitting unit 6, to the vehicle lower portion microphone, which is the vehicle lower portion noise detector 120, when inequality X<(RX+Adj1*S), the alarm sound is generated. At this moment, the amplified volume of alarm sound, Sadj, is controlled to become equality Sadj=Adj_a*(RX−X), by using the attenuation adjusting factor, Adj_a, in the space at a specified distance from the alarm sound generation speaker as shown in Table 1. In Table 1, the alarm sound is not generated when inequality X≦(RX+Adj1*S). At this moment, the volume of alarm sound is equation Sadj=0.
In Table 2, when inequality X≦(RX+Adj1*S), by using as the alarm sound the noise the electric moving body generates by itself explained in Embodiment 6, alarm sound in the reversed phase of this noise is generated, and the noise the electric moving body generates is canceled out at the position at the specified distance from the electric moving body, so that the noise from the electric moving body at the position is controlled to become a volume equivalent to the volume the electric moving body generates, equation X=(RX+Adj1*S). At this moment, the volume of adjusted alarm sound is made equation Sadj=Adj_a*(X−RX), by using the attenuation adjusting factor Adj_a of the phase-reversed alarm sound in the space at the specified distance from the alarm sound generation speaker, which is the sound-emitting unit 6.
Tables 3 and 4 show examples when the electric moving body noise level comparison determination unit 2 makes determination, as described in Embodiment 2, using the noise that is generated by the electric moving body itself and detected by the electric moving body noise detection unit 1 and the ambient generation noise detected by the ambient noise detection unit 7. As shown in Tables 3 and 4, by using a volume difference Z between the noise the electric moving body generates by itself and ambient generation noise, a specified volume difference i between the noise the electric moving body generates by itself, which is a preset specific volume, and the ambient generation noise, the volume of preset alarm sound S, and the attenuation adjusting factor Adj1 in the space from the alarm sound generation speaker, which is the sound-emitting unit 6, to the vehicle lower portion microphone, which is the vehicle lower portion noise detector 120, and the vehicle (upper) portion microphone, which is the vehicle upper portion noise detector 110, the first predetermined volume described in Embodiment 2 is specified as RZ+Adj1*S. When inequality Z<(RZ+Adj1*S), the alarm sound is generated. The amplified volume of alarm sound Sadj at this moment is controlled to become equation Sadj=Adj_a*(RZ−Z) by using the attenuation adjusting factor Adj_a in the space at the specified distance from the alarm sound generation speaker as shown in Tables 3 and 4.
In Table 3, the alarm sound is not generated when inequality Z≦(RZ+Adj1*S). At this moment, the volume of alarm sound is equation Sadj=0. In Table 4, a volume of RZ2+Adj1*S, which is greater than the first predetermined volume, is specified as the second predetermined volume described in Embodiment 2. When inequality (RZ+Adj1*S)≦Z<(RZ2+Adj1*S), the alarm sound is not generated. Furthermore, when inequality Z≧(RZ2+Adj1*S), by using as the alarm sound the noise the electric moving body generates by itself described in Embodiment 6, alarm sound in the reversed phase of this noise is generated. By generating the alarm sound in the reversed phase, the noise the electric moving body generates is canceled out at the position at the specified distance from the electric moving body. The noise from the electric moving body at the position is controlled to have a volume equivalent to the volume the electric moving body generates, equation X=(RX+Adj1*S), the same as that described in Table 2, for example. At this moment, the volume of alarm sound is made equation Sadj=Adj_a*(X−RX), by using the attenuation adjusting factor Adj_a of the phase-reversed alarm sound in the space at the specified distance from the alarm sound generation speaker.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/063819 | 8/16/2010 | WO | 00 | 11/5/2012 |
