Automobile noise monitoring system

Abstract

The invention discloses an automobile noise monitoring system, and relates to the field of vehicles. Comprising a detection part arranged on the outer side of a vehicle and a processing display part arranged in the vehicle, and the detection part comprises a first shell fixed outside a vehicle body and a sensor module fixed to the outer wall of the first shell and used for wind speed detection; the processing display part comprises a second shell fixed in the vehicle through a fixing base, the outer side of the second shell is provided with a double-color lamp display type logo display area, a noise size display area and a loudspeaker box, a central processing main board is arranged in the second shell, and a back plate is fixed to the back of the second shell. The vehicle speed information and the noise information of the vehicle are collected in real time based on the sensor module, and then the abnormal information of the vehicle can be reported to the traffic administration bureau in time through the communication unit when the vehicle is abnormal by adopting a mode based on threshold control, so that full-coverage real-time supervision of the vehicle is realized.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and in particular to an automobile noise monitoring system. Background Art

[0002] With the development of the automobile industry and the improvement of people's economic ability, the quality, production speed, and functionality of vehicles have been greatly improved, which has greatly increased the number of vehicles in use, which has also greatly increased road pressure and vehicle management pressure.

[0003] In vehicle management, speeding and illegal modification, which are key monitoring items for vehicles, are very harmful. The noise caused by speeding and illegal modification also disturbs the public.

[0004] Traditional vehicle noise monitoring relies on fixed road noise monitoring stations, which suffer from limited coverage and poor real-time performance. Furthermore, the use of fixed-point radar speed measurement for speeding also results in limited coverage, and inaccurate speed measurement within certain intervals, which can be easily exploited by drivers. Furthermore, existing on-board systems lack targeted identification and reporting mechanisms, making real-time monitoring impossible.

[0005] To this end, the present invention provides a vehicle noise monitoring system. Summary of the Invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an automobile noise monitoring system.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: An automobile noise monitoring system includes a detection part arranged on the outside of the vehicle and a processing and display part arranged on the inside of the vehicle, wherein: The detection part includes a shell 1 fixed to the outside of the vehicle body, and a sensor module fixed to the outer wall of the shell 1 and used for wind speed detection; The processing and display portion includes a second housing fixed to the interior of the vehicle via a fixed base, the outer side of the second housing being respectively provided with a two-color light display logo display area, a noise level display area, and a speaker, the interior of the second housing being provided with a central processing motherboard, and a back plate being fixed to the back of the second housing, and the central processing motherboard being electrically connected to the two-color light display logo display area, the noise level display area, and the speaker; The signal output end of the sensor module is connected to the signal receiving end of the central processing mainboard through a data connection line. The data connection line is arranged along the vehicle body and passes through the back plate.

[0008] Preferably, the sensor module is composed of a noise sensor and a laser wind speed sensor, and the central processing mainboard is equipped with a communication unit, a positioning unit and a weather forecast unit.

[0009] Preferably, the working logic of the automobile noise monitoring system includes the following steps: S1: The sensor module acquires environmental data and transmits it to the central processing board. The central processing board determines the vehicle's current speed and its own noise based on the acquired data. S2: The central processing board determines whether the vehicle is speeding based on the current speed of the vehicle and the speed limit information of the area where the vehicle is located by the positioning unit. If speeding occurs, the dual-color light logo display area will display a red light, and the speaker will issue a speeding warning. In addition, the central processing board uploads the speeding information to the traffic management bureau through the communication unit. Otherwise, the dual-color light logo display area will display a green light, and the speaker will not work. S3: The central processing motherboard determines the vehicle noise situation based on the vehicle's own noise and combined with a threshold control algorithm. If it is determined to be an illegal modification, the two-color light logo display area will display a red light, and the speaker will issue an illegal modification warning. In addition, the central processing motherboard uploads the noise information to the traffic management bureau through the communication unit. Otherwise, the two-color light logo display area will display a green light and the speaker will not work.

[0010] Preferably, in step S1, the method for determining the current speed of the vehicle includes the following steps: A1: Establish a speed correlation model, which is: ,in is the velocity vector of the vehicle relative to the particles in the air detected by the laser wind speed sensor, is the wind speed vector relative to the ground stationary environment obtained from the weather forecast unit, is the velocity vector of the particles vibrating in the ambient noise air in the area where the vehicle is currently located; A2: Determine the particle fluctuation value in the air caused by environmental noise based on the speed fluctuation value detected by the wind speed sensor, and determine the value based on the fluctuation curve. The value of the wind speed vector relative to the ground stationary environment obtained by the weather forecast unit as well as get ; A3: According to the obtained , determine the final vehicle speed .

[0011] Preferably, in step S1, the method for determining the vehicle's own noise includes the following steps: B1: Establish a noise correlation model, ,in is the total noise detected by the noise sensor, Wind noise is caused by the relative movement between the vehicle and the air. is the noise in the vehicle's environment, Noise generated by the vehicle itself; B2: Establish a wind noise-vehicle speed coupling model, collect dynamic air pressure data, and combine it with a fluid mechanics model to establish a wind noise-vehicle speed coupling model , where wind noise is the noise generated by the relative motion between the vehicle and the air, so in this model , here; B3: Establishing a model of sound waves and particle vibrations Where d and f are the size and frequency of the sound wave, which is the noise of the environment itself, respectively, and V is the movement of particles in the air. The movement of d is determined by ; B4: Based on what is obtained in B2 , obtained in B3 and the total noise detected by the noise sensor , combined with the noise correlation model in B1 to obtain the vehicle's own noise .

[0012] Preferably, in step B2, the wind noise-vehicle speed coupling model is: ,in: ρ is the air density, ρ=1.225kg / m³; v is the vehicle speed, v= ; is the vehicle drag coefficient, which is matched through the vehicle model database; A is the vehicle's frontal area, which is determined based on the vehicle's shape data and the direction of the vehicle's movement relative to the air; is the reference sound pressure, =20μPa.

[0013] Preferably: in step B3, the sound wave and particle vibration model is: ,in: The magnitude of the boost in ambient self-noise at time t is p; ρ is the air density, ρ=1.225kg / m³; c is the speed of sound, c=343m / S; V(t) represents the particle velocity V at time t. , which is obtained in step A2, x is the displacement distance of the particle; A is the amplitude, which represents the maximum displacement distance of the particle; f is the frequency of the environment's own noise, which can be directly extracted from the particle vibration displacement signal x(t).

[0014] Preferably: in the step B3, ,in: ; is the reference sound pressure, =20μPa.

[0015] Preferably, in step S3, the threshold control algorithm determines the vehicle noise logic as follows: S31: Acquire the noise generated by the vehicle itself , and use wavelet packet transform to decompose the noise signal, extract the energy proportion of a-bkHz frequency band as the feature quantity; S32: Set the percentage threshold and time thresholds , , ; S33: When the measured energy ratio of the ab kHz band is greater than the threshold And the duration exceeds the time threshold Later, it was determined to be an illegally modified roaring car.

[0016] Preferably, in the step S31, the energy proportion of the ab kHz frequency band is calculated as follows: ,in: is the signal component after wavelet packet transformation, corresponding to the time domain waveform of frequency f; is the energy integral of the wavelet packet signal component corresponding to frequency f in the time domain; a, b, c, and d are constants determined based on actual noise.

[0017] The beneficial effects of the present invention are: The present invention collects vehicle speed and noise information in real time based on a sensor module, and then uses a threshold-based control method to report vehicle abnormality information to the traffic management bureau through a communication unit in a timely manner when the vehicle is abnormal, thereby achieving real-time supervision with full coverage of vehicles.

[0018] The present invention monitors the vehicle speed and noise by utilizing a laser wind speed sensor and a noise sensor, and combining a speed correlation model, a noise correlation model, a wind noise-vehicle speed coupling model, and a sound wave and particle vibration model. This can eliminate the environmental noise itself and the wind noise generated by the vehicle movement during noise monitoring, thereby ensuring the accuracy of monitoring the noise generated by the vehicle itself.

[0019] The present invention judges noise anomalies based on precise monitoring of noise levels, adopts a threshold control algorithm to judge anomalies, and uses the frequency band energy ratio as the basis for anomaly judgment, so that different vehicle parts and abnormal modification situations can be monitored according to the settings of different constants in the calculation formula. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall decomposition structure of an automobile noise monitoring system proposed by the present invention; Figure 2 This is a schematic diagram of the decomposition structure of the processing and display part of the automobile noise monitoring system proposed by the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be further described in detail below in conjunction with specific implementation methods.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "disposed" should be understood in a broad sense. For example, they may refer to fixed connection or disposition, detachable connection or disposition, or integral connection or disposition. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0023] Example 1: An automobile noise monitoring system includes a detection portion disposed on the outside of the vehicle and a processing and display portion disposed on the inside of the vehicle, wherein: The detection part includes a housing 2 fixed to the outside of the vehicle body, and a sensor module 1 fixed to the outer wall of the housing 2 and used for wind speed detection; The processing and display part includes a second housing 8 fixed to the interior of the vehicle via a fixed base 7. The outer side of the second housing 8 is respectively provided with a two-color light display logo display area 4, a noise level display area 5 and a speaker 6. The interior of the second housing 8 is provided with a central processing motherboard 10, and a back plate 9 is fixed to the back of the second housing 8. The central processing motherboard 10 is electrically connected to the two-color light display logo display area 4, the noise level display area 5 and the speaker 6. The signal output end of the sensor module 1 is connected to the signal receiving end of the central processing motherboard 10 through a data connection line 3 . The data connection line 3 is arranged along the vehicle body and passes through the back plate 9 .

[0024] The sensor module 1 is composed of a noise sensor and a laser wind speed sensor, and the central processing motherboard 10 is built with a communication unit, a positioning unit and a weather forecast unit.

[0025] The working logic of the automobile noise monitoring system includes the following steps: S1: The sensor module 1 acquires environmental data and transmits it to the central processing board 10. The central processing board 10 determines the current speed of the vehicle and the vehicle's own noise based on the acquired data; S2: The central processing motherboard 10 determines whether the vehicle is speeding based on the current speed of the vehicle and the speed limit information of the area where the vehicle is located by the positioning unit. If speeding occurs, the two-color light display logo display area 4 will display a red light, and the speaker 6 will issue a speeding warning. In addition, the central processing motherboard 10 uploads the speeding information to the traffic control bureau through the communication unit. Otherwise, the two-color light display logo display area 4 will display a green light, and the speaker 6 will not work; S3: The central processing motherboard 10 judges the vehicle noise condition based on the vehicle's own noise and in combination with a threshold control algorithm. If it is determined to be an illegal modification, the two-color light logo display area 4 will display a red light, and the speaker 6 will issue an illegal modification warning. In addition, the central processing motherboard 10 uploads the noise information to the traffic management bureau through the communication unit. Otherwise, the two-color light logo display area 4 will display a green light, and the speaker 6 will not work.

[0026] Example 2: An automobile noise monitoring system includes a detection portion disposed on the outside of the vehicle and a processing and display portion disposed on the inside of the vehicle, wherein: The detection part includes a housing 2 fixed to the outside of the vehicle body, and a sensor module 1 fixed to the outer wall of the housing 2 and used for wind speed detection; The processing and display part includes a second housing 8 fixed to the interior of the vehicle via a fixed base 7. The outer side of the second housing 8 is respectively provided with a two-color light display logo display area 4, a noise level display area 5 and a speaker 6. The interior of the second housing 8 is provided with a central processing motherboard 10, and a back plate 9 is fixed to the back of the second housing 8. The central processing motherboard 10 is electrically connected to the two-color light display logo display area 4, the noise level display area 5 and the speaker 6. The signal output end of the sensor module 1 is connected to the signal receiving end of the central processing motherboard 10 through a data connection line 3 . The data connection line 3 is arranged along the vehicle body and passes through the back plate 9 .

[0027] The sensor module 1 is composed of a noise sensor and a laser wind speed sensor, and the central processing motherboard 10 is built with a communication unit, a positioning unit and a weather forecast unit.

[0028] The working logic of the automobile noise monitoring system includes the following steps: S1: The sensor module 1 acquires environmental data and transmits it to the central processing board 10. The central processing board 10 determines the current speed of the vehicle and the vehicle's own noise based on the acquired data; S2: The central processing motherboard 10 determines whether the vehicle is speeding based on the current speed of the vehicle and the speed limit information of the area where the vehicle is located by the positioning unit. If speeding occurs, the two-color light display logo display area 4 will display a red light, and the speaker 6 will issue a speeding warning. In addition, the central processing motherboard 10 uploads the speeding information to the traffic control bureau through the communication unit. Otherwise, the two-color light display logo display area 4 will display a green light, and the speaker 6 will not work; S3: The central processing motherboard 10 judges the vehicle noise condition based on the vehicle's own noise and in combination with a threshold control algorithm. If it is determined to be an illegal modification, the two-color light logo display area 4 will display a red light, and the speaker 6 will issue an illegal modification warning. In addition, the central processing motherboard 10 uploads the noise information to the traffic management bureau through the communication unit. Otherwise, the two-color light logo display area 4 will display a green light, and the speaker 6 will not work.

[0029] In step S1, the method for determining the current speed of the vehicle includes the following steps: A1: Establish a speed correlation model, which is: ,in is the velocity vector of the vehicle relative to the particles in the air detected by the laser wind speed sensor, is the wind speed vector relative to the ground stationary environment obtained from the weather forecast unit, is the velocity vector of the particles vibrating in the ambient noise air in the area where the vehicle is currently located; A2: When environmental noise is transmitted, air is used as the transmission medium, and the particles in the air will also vibrate. However, in a short period of time, it can be assumed that the wind speed and vehicle speed are fixed values. The fluctuation value is The fluctuation value of the sound wave is a sine or cosine function, so the particle vibration caused by it is also a simple harmonic vibration. At the same time, the propagation of sound waves is achieved by the vibration of the object to stimulate the vibration of the particles in the surrounding medium. The vibration direction of these particles is consistent with the propagation direction of the sound wave, forming a longitudinal wave. The propagation mode of sound waves is the propagation of energy, not the movement of matter. The particles do not diffuse forward with the sound wave, but vibrate near their equilibrium position. Based on this, the particle fluctuation value in the air caused by environmental noise is determined according to the speed fluctuation value detected by the wind speed sensor, and the fluctuation curve is determined. The value of the wind speed vector relative to the ground stationary environment obtained by the weather forecast unit as well as get ; A3: According to the obtained , determine the final vehicle speed .

[0030] Example 3: An automobile noise monitoring system includes a detection portion disposed on the outside of the vehicle and a processing and display portion disposed on the inside of the vehicle, wherein: The detection part includes a housing 2 fixed to the outside of the vehicle body, and a sensor module 1 fixed to the outer wall of the housing 2 and used for wind speed detection; The processing and display part includes a second housing 8 fixed to the interior of the vehicle via a fixed base 7. The outer side of the second housing 8 is respectively provided with a two-color light display logo display area 4, a noise level display area 5 and a speaker 6. The interior of the second housing 8 is provided with a central processing motherboard 10, and a back plate 9 is fixed to the back of the second housing 8. The central processing motherboard 10 is electrically connected to the two-color light display logo display area 4, the noise level display area 5 and the speaker 6. The signal output end of the sensor module 1 is connected to the signal receiving end of the central processing motherboard 10 through a data connection line 3 . The data connection line 3 is arranged along the vehicle body and passes through the back plate 9 .

[0031] The sensor module 1 is composed of a noise sensor and a laser wind speed sensor, and the central processing motherboard 10 is built with a communication unit, a positioning unit and a weather forecast unit.

[0032] The working logic of the automobile noise monitoring system includes the following steps: S1: The sensor module 1 acquires environmental data and transmits it to the central processing board 10. The central processing board 10 determines the current speed of the vehicle and the vehicle's own noise based on the acquired data; S2: The central processing motherboard 10 determines whether the vehicle is speeding based on the current speed of the vehicle and the speed limit information of the area where the vehicle is located by the positioning unit. If speeding occurs, the two-color light display logo display area 4 will display a red light, and the speaker 6 will issue a speeding warning. In addition, the central processing motherboard 10 uploads the speeding information to the traffic control bureau through the communication unit. Otherwise, the two-color light display logo display area 4 will display a green light, and the speaker 6 will not work; S3: The central processing motherboard 10 judges the vehicle noise condition based on the vehicle's own noise and in combination with a threshold control algorithm. If it is determined to be an illegal modification, the two-color light logo display area 4 will display a red light, and the speaker 6 will issue an illegal modification warning. In addition, the central processing motherboard 10 uploads the noise information to the traffic management bureau through the communication unit. Otherwise, the two-color light logo display area 4 will display a green light, and the speaker 6 will not work.

[0033] In step S1, the method for determining the current speed of the vehicle includes the following steps: A1: Establish a speed correlation model, which is: ,in is the velocity vector of the vehicle relative to the particles in the air detected by the laser wind speed sensor, is the wind speed vector relative to the ground stationary environment obtained from the weather forecast unit, is the velocity vector of the particles vibrating in the ambient noise air in the area where the vehicle is currently located; A2: When environmental noise is transmitted, air is used as the transmission medium, and the particles in the air will also vibrate. However, in a short period of time, it can be assumed that the wind speed and vehicle speed are fixed values. The fluctuation value is The fluctuation value of the sound wave is a sine or cosine function, so the particle vibration caused by it is also a simple harmonic vibration. At the same time, the propagation of sound waves is achieved by the vibration of the object to stimulate the vibration of the particles in the surrounding medium. The vibration direction of these particles is consistent with the propagation direction of the sound wave, forming a longitudinal wave. The propagation mode of sound waves is the propagation of energy, not the movement of matter. The particles do not diffuse forward with the sound wave, but vibrate near their equilibrium position. Based on this, the particle fluctuation value in the air caused by environmental noise is determined according to the speed fluctuation value detected by the wind speed sensor, and the fluctuation curve is determined. The value of the wind speed vector relative to the ground stationary environment obtained by the weather forecast unit as well as get ; A3: According to the obtained , determine the final vehicle speed .

[0034] In step S1, the method for determining the vehicle's own noise includes the following steps: B1: Establish a noise correlation model, ,in is the total noise detected by the noise sensor, Wind noise is caused by the relative movement between the vehicle and the air. is the noise in the vehicle's environment, Noise generated by the vehicle itself; B2: Establish a wind noise-vehicle speed coupling model, collect dynamic air pressure data, and combine it with a fluid mechanics model to establish a wind noise-vehicle speed coupling model , where wind noise is the noise generated by the relative motion between the vehicle and the air, so in this model , here; B3: Establishing a model of sound waves and particle vibrations Where d and f are the size and frequency of the sound wave, which is the noise of the environment itself, respectively, and V is the movement of particles in the air. The movement of d is determined by ; B4: Based on what is obtained in B2 , obtained in B3 and the total noise detected by the noise sensor , combined with the noise correlation model in B1 to obtain the vehicle's own noise .

[0035] In step B2, the wind noise-vehicle speed coupling model is: ,in: ρ is the air density, ρ=1.225kg / m³; v is the vehicle speed, v= ; is the vehicle drag coefficient, which is matched through the vehicle model database; A is the vehicle's frontal area, which is determined based on the vehicle's shape data and the direction of the vehicle's movement relative to the air; is the reference sound pressure, =20μPa.

[0036] In step B3, the sound wave and particle vibration model is: ,in: The magnitude of the boost in ambient self-noise at time t is p; ρ is the air density, ρ=1.225kg / m³; c is the speed of sound, c=343m / S; V(t) represents the particle velocity V at time t. , which is obtained in step A2, x is the displacement distance of the particle; A is the amplitude, which represents the maximum displacement distance of the particle; f is the frequency of the environment's own noise, which can be directly extracted from the particle vibration displacement signal x(t).

[0037] In the step B3, ,in: ; is the reference sound pressure, =20μPa.

[0038] In step S3, the threshold control algorithm determines the vehicle noise logic as follows: S31: Acquire the noise generated by the vehicle itself , and use wavelet packet transform to decompose the noise signal, extract the energy proportion of a-bkHz frequency band as the feature quantity; S32: Set the percentage threshold and time thresholds , , ; S33: When the measured energy ratio of the ab kHz band is greater than the threshold And the duration exceeds the time threshold Later, it was determined to be an illegally modified roaring car.

[0039] Example 4: An automobile noise monitoring system includes a detection portion disposed on the outside of the vehicle and a processing and display portion disposed on the inside of the vehicle, wherein: The detection part includes a housing 2 fixed to the outside of the vehicle body, and a sensor module 1 fixed to the outer wall of the housing 2 and used for wind speed detection; The processing and display part includes a second housing 8 fixed to the interior of the vehicle via a fixed base 7. The outer side of the second housing 8 is respectively provided with a two-color light display logo display area 4, a noise level display area 5 and a speaker 6. The interior of the second housing 8 is provided with a central processing motherboard 10, and a back plate 9 is fixed to the back of the second housing 8. The central processing motherboard 10 is electrically connected to the two-color light display logo display area 4, the noise level display area 5 and the speaker 6. The signal output end of the sensor module 1 is connected to the signal receiving end of the central processing motherboard 10 through a data connection line 3 . The data connection line 3 is arranged along the vehicle body and passes through the back plate 9 .

[0040] The sensor module 1 is composed of a noise sensor and a laser wind speed sensor, and the central processing motherboard 10 is built with a communication unit, a positioning unit and a weather forecast unit.

[0041] The working logic of the automobile noise monitoring system includes the following steps: S1: The sensor module 1 acquires environmental data and transmits it to the central processing board 10. The central processing board 10 determines the current speed of the vehicle and the vehicle's own noise based on the acquired data; S2: The central processing motherboard 10 determines whether the vehicle is speeding based on the current speed of the vehicle and the speed limit information of the area where the vehicle is located by the positioning unit. If speeding occurs, the two-color light display logo display area 4 will display a red light, and the speaker 6 will issue a speeding warning. In addition, the central processing motherboard 10 uploads the speeding information to the traffic control bureau through the communication unit. Otherwise, the two-color light display logo display area 4 will display a green light, and the speaker 6 will not work; S3: The central processing motherboard 10 judges the vehicle noise condition based on the vehicle's own noise and in combination with a threshold control algorithm. If it is determined to be an illegal modification, the two-color light logo display area 4 will display a red light, and the speaker 6 will issue an illegal modification warning. In addition, the central processing motherboard 10 uploads the noise information to the traffic management bureau through the communication unit. Otherwise, the two-color light logo display area 4 will display a green light, and the speaker 6 will not work.

[0042] In step S1, the method for determining the current speed of the vehicle includes the following steps: A1: Establish a speed correlation model, which is: ,in is the velocity vector of the vehicle relative to the particles in the air detected by the laser wind speed sensor, is the wind speed vector relative to the ground stationary environment obtained from the weather forecast unit, is the velocity vector of the particles vibrating in the ambient noise air in the area where the vehicle is currently located; A2: When environmental noise is transmitted, air is used as the transmission medium, and the particles in the air will also vibrate. However, in a short period of time, it can be assumed that the wind speed and vehicle speed are fixed values. The fluctuation value is The fluctuation value of the sound wave is a sine or cosine function, so the particle vibration caused by it is also a simple harmonic vibration. At the same time, the propagation of sound waves is achieved by the vibration of the object to stimulate the vibration of the particles in the surrounding medium. The vibration direction of these particles is consistent with the propagation direction of the sound wave, forming a longitudinal wave. The propagation mode of sound waves is the propagation of energy, not the movement of matter. The particles do not diffuse forward with the sound wave, but vibrate near their equilibrium position. Based on this, the particle fluctuation value in the air caused by environmental noise is determined according to the speed fluctuation value detected by the wind speed sensor, and the fluctuation curve is determined. The value of the wind speed vector relative to the ground stationary environment obtained by the weather forecast unit as well as get ; A3: According to the obtained , determine the final vehicle speed .

[0043] In step S1, the method for determining the vehicle's own noise includes the following steps: B1: Establish a noise correlation model, ,in is the total noise detected by the noise sensor, Wind noise is caused by the relative movement between the vehicle and the air. is the noise in the vehicle's environment, Noise generated by the vehicle itself; B2: Establish a wind noise-vehicle speed coupling model, collect dynamic air pressure data, and combine it with a fluid mechanics model to establish a wind noise-vehicle speed coupling model , where wind noise is the noise generated by the relative motion between the vehicle and the air, so in this model , here; B3: Establishing a model of sound waves and particle vibrations Where d and f are the size and frequency of the sound wave, which is the noise of the environment itself, respectively, and V is the movement of particles in the air. The movement of d is determined by ; B4: Based on what is obtained in B2 , obtained in B3 and the total noise detected by the noise sensor , combined with the noise correlation model in B1 to obtain the vehicle's own noise .

[0044] In step B2, the wind noise-vehicle speed coupling model is: ,in: ρ is the air density, ρ=1.225kg / m³; v is the vehicle speed, v= ; is the vehicle drag coefficient, which is matched through the vehicle model database; A is the vehicle's frontal area, which is determined based on the vehicle's shape data and the direction of the vehicle's movement relative to the air; is the reference sound pressure, =20μPa.

[0045] In step B3, the sound wave and particle vibration model is: ,in: The magnitude of the boost in ambient self-noise at time t is p; ρ is the air density, ρ=1.225kg / m³; c is the speed of sound, c=343m / S; V(t) represents the particle velocity V at time t. , which is obtained in step A2, x is the displacement distance of the particle; A is the amplitude, which represents the maximum displacement distance of the particle; f is the frequency of the environment's own noise, which can be directly extracted from the particle vibration displacement signal x(t).

[0046] In the step B3, ,in: ; is the reference sound pressure, =20μPa.

[0047] In step S3, the threshold control algorithm determines the vehicle noise logic as follows: S31: Acquire the noise generated by the vehicle itself , and use wavelet packet transform to decompose the noise signal, extract the energy proportion of a-bkHz frequency band as the feature quantity; S32: Set the percentage threshold and time thresholds , , ; S33: When the measured energy ratio of the ab kHz band is greater than the threshold And the duration exceeds the time threshold Later, it was determined to be an illegally modified roaring car.

[0048] In step S31, the energy ratio of the ab kHz band is calculated as follows: ,in: is the signal component after wavelet packet transformation, corresponding to the time domain waveform of frequency f; is the energy integral of the wavelet packet signal component corresponding to frequency f in the time domain; a, b, c, and d are constants determined based on actual noise. This embodiment does not impose any restrictions on them. They can be determined based on the noise frequency range of the specific vehicle monitoring location. For example, normal engine noise energy is mainly concentrated in low frequencies (<1 kHz), such as exhaust sounds and mechanical friction sounds. Abnormal noise (such as knock and turbine whine) often has a significant increase in energy in the 1-4 kHz frequency band. Therefore, a and b can be 1 and 4, respectively, which can cover the typical frequency bands of high-frequency abnormal noises of the engine (such as valve knock and bearing wear). c and d cover the entire audible range of the engine operating noise to avoid missing low-frequency interference. c and d can be set to 0.1 and 20, respectively.

[0049] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A car noise monitoring system, characterized in that: It includes a detection part arranged on the outside of the vehicle and a processing and display part arranged on the inside of the vehicle, wherein: The detection part includes a shell (2) fixed to the outside of the vehicle body, and a sensor module (1) fixed to the outer wall of the shell (2) and used for wind speed detection; The processing and display part includes a second shell (8) fixed to the interior of the vehicle via a fixed base (7), the outer side of the second shell (8) is respectively provided with a two-color light display logo display area (4), a noise level display area (5) and a speaker (6), the interior of the second shell (8) is provided with a central processing motherboard (10), and a back plate (9) is fixed to the back of the second shell (8), and the central processing motherboard (10) is electrically connected to the two-color light display logo display area (4), the noise level display area (5) and the speaker (6); The signal output end of the sensor module (1) is connected to the signal receiving end of the central processing mainboard (10) via a data connection line (3), and the data connection line (3) is arranged along the vehicle body and passes through the back plate (9).

2. The automobile noise monitoring system according to claim 1, characterized in that: The sensor module (1) is composed of a noise sensor and a laser wind speed sensor, and the central processing mainboard (10) is equipped with a communication unit, a positioning unit, and a weather forecast unit.

3. The automobile noise monitoring system according to claim 1 or 2, characterized in that: The working logic of the automobile noise monitoring system includes the following steps: S1: The sensor module (1) acquires environmental data and transmits it to the central processing board (10). The central processing board (10) determines the current speed of the vehicle and the vehicle's own noise based on the acquired data; S2: The central processing motherboard (10) determines whether the vehicle is speeding based on the current speed of the vehicle and the speed limit information of the area where the vehicle is located by the positioning unit. When speeding occurs, the two-color light display logo display area (4) will display a red light, and the speaker (6) will issue a speeding warning. In addition, the central processing motherboard (10) uploads the speeding information to the traffic management bureau through the communication unit. Otherwise, the two-color light display logo display area (4) will display a green light, and the speaker (6) will not work. S3: The central processing motherboard (10) judges the vehicle noise situation based on the vehicle's own noise and in combination with the threshold control algorithm. If it is determined to be an illegal modification, the two-color light display logo display area (4) will display a red light, and the speaker (6) will issue an illegal modification warning. In addition, the central processing motherboard (10) uploads the noise information to the traffic management bureau through the communication unit. Otherwise, the two-color light display logo display area (4) will display a green light, and the speaker (6) will not work.

4. The automobile noise monitoring system according to claim 3, characterized in that: In step S1, the method for determining the current speed of the vehicle includes the following steps: A1: Establish a speed correlation model, which is: ,in is the velocity vector of the vehicle relative to the particles in the air detected by the laser wind speed sensor, is the wind speed vector relative to the ground stationary environment obtained from the weather forecast unit, is the velocity vector of the particles vibrating in the ambient noise air in the area where the vehicle is currently located; A2: Determine the particle fluctuation value in the air caused by environmental noise based on the speed fluctuation value detected by the wind speed sensor, and determine the value based on the fluctuation curve. The value of the wind speed vector relative to the ground stationary environment obtained by the weather forecast unit as well as get ; A3: According to the obtained , determine the final vehicle speed .

5. The automobile noise monitoring system according to claim 4, characterized in that: In step S1, the method for determining the vehicle's own noise includes the following steps: B1: Establish a noise correlation model, ,in is the total noise detected by the noise sensor, Wind noise is caused by the relative movement between the vehicle and the air. is the noise in the vehicle's environment, Noise generated by the vehicle itself; B2: Establish a wind noise-vehicle speed coupling model, collect dynamic air pressure data, and combine it with a fluid mechanics model to establish a wind noise-vehicle speed coupling model , where wind noise is the noise generated by the relative motion between the vehicle and the air, so in this model , here; B3: Establishing a model of sound waves and particle vibrations Where d and f are the size and frequency of the sound wave, which is the noise of the environment itself, respectively, and V is the movement of particles in the air. The movement of d is determined by ; B4: Based on what is obtained in B2 , obtained in B3 and the total noise detected by the noise sensor , combined with the noise correlation model in B1 to obtain the vehicle's own noise .

6. The automobile noise monitoring system according to claim 5, characterized in that: In step B2, the wind noise-vehicle speed coupling model is: ,in: ρ is the air density, ρ=1.225kg / m³; v is the vehicle speed, v= ; is the vehicle drag coefficient, which is matched through the vehicle model database; A is the vehicle's frontal area, which is determined based on the vehicle's shape data and the direction of the vehicle's movement relative to the air; is the reference sound pressure, =20μPa.

7. The automobile noise monitoring system according to claim 5, characterized in that: In step B3, the sound wave and particle vibration model is: ,in: The magnitude of the boost in ambient self-noise at time t is p; ρ is the air density, ρ=1.225kg / m³; c is the speed of sound, c=343m / S; V(t) represents the particle velocity V at time t. , which is obtained in step A2, x is the displacement distance of the particle; A is the amplitude, which represents the maximum displacement distance of the particle; f is the frequency of the environment's own noise, which can be directly extracted from the particle vibration displacement signal x(t).

8. The automobile noise monitoring system according to claim 7, characterized in that: In the step B3, ,in: ； is the reference sound pressure, =20μPa.

9. The automobile noise monitoring system according to claim 3, characterized in that: In step S3, the threshold control algorithm determines the vehicle noise logic as follows: S31: Acquire the noise generated by the vehicle itself , and use wavelet packet transform to decompose the noise signal, extract the energy proportion of a-bkHz frequency band as the feature quantity; S32: Set the percentage threshold and time thresholds , , ; S33: When the measured energy ratio of the ab kHz band is greater than the threshold And the duration exceeds the time threshold Later, it was determined to be an illegally modified roaring car.

10. The automobile noise monitoring system according to claim 9, characterized in that: In step S31, the energy ratio of the a-bkHz frequency band is calculated as follows: ,in: is the signal component after wavelet packet transformation, corresponding to the time domain waveform of frequency f; is the energy integral of the wavelet packet signal component corresponding to frequency f in the time domain; a, b, c, and d are constants determined based on actual noise.

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