Vehicle load monitoring method for monitoring engine operation audio signal

Abstract

The invention discloses a vehicle load monitoring method for monitoring an engine operation audio signal. The method comprises the following steps: acquiring engine audio data through audio acquisition equipment; the audio signal of the engine is analyzed, information about the rotating speed of the engine is extracted, and then the rotating speed of the engine is calculated; obtaining the output power of the engine at different rotating speeds according to the engine working condition diagram; the running speed, obtained by the gyroscope, of the automobile is obtained, and wheel driving force is calculated according to a power formula; calculating the longitudinal traction force applied to the vehicle in the moving process; the vehicle acceleration is obtained from the gyroscope, the vehicle load is calculated based on the Newton second law, and whether the vehicle is overloaded or not can be known by comparing the vehicle load with the specified load. The vehicle can be weighed at any time without being limited by the position, and the management efficiency of related departments and vehicle managers is improved.

Description

Technical Field

[0001] The invention relates to the field of vehicle control, and in particular to a vehicle load monitoring method by monitoring an engine operation audio signal. Background Art

[0002] With the rapid development of the transportation industry, accurate measurement of vehicle load is of vital importance to ensure road safety, reduce transportation costs and improve transportation efficiency. In the existing technical field, the main methods for measuring vehicle load are static weighing technology, dynamic weighing technology and on-board weighing technology.

[0003] Static weighing technology: mainly uses an electronic floor scale installed on the ground to weigh passing vehicles [1].

[0004] Dynamic weighing technology: There are two main types of axle weight detection and bridge strain detection. Axle weight detection mainly uses dynamic weighing sensors buried on the road surface to measure the pressure signal of the tires of moving vehicles on the ground, thereby obtaining rich vehicle information such as vehicle speed, wheelbase, axle weight, and total weight. Bridge strain detection uses sensors installed at the bottom of the bridge to obtain the bridge response generated when the vehicle under test passes through the bridge, and uses the established algorithm to reversely calculate the speed, number of axles, wheelbase, axle weight and other information of the vehicle under test.

[0005] On-board weighing technology: mainly through the installation of sensors on the load-bearing parts of the vehicle, collect the data on the load-bearing parts that change with the load, and achieve weighing by establishing a corresponding relationship between the collected data and the load. Common installation locations include the surface of leaf springs, the bottom of the frame beam, the surface of the axle, etc.

[0006] Static weighing technology requires measurement after the vehicle has come to a complete stop, so its measurement efficiency is low and is not conducive to large-scale application.

[0007] Although dynamic weighing technology can measure the load of a moving vehicle, the weighing equipment is separated from the vehicle, making it impossible to achieve real-time monitoring of the vehicle status, and it is difficult to carry out overload control in areas where underground weighing equipment cannot be laid.

[0008] On-board weighing sensors are usually installed at the bottom of the car and are easily affected by the surrounding environment, such as high temperature, low temperature, humidity, dust, etc. These factors may cause damage to the sensor or increase the error, increasing maintenance costs and workload. At the same time, under harsh road conditions, the sensor is easily disturbed by vehicle vibration and impact, and the accuracy may decrease. In addition, the R&D and production costs of overload detection sensors are high. Summary of the invention

[0009] The purpose of the present invention is to provide a vehicle load monitoring method by monitoring the audio signal of the engine operation, which solves the problems that other load detection methods cannot be dynamically monitored and the monitoring cost is high, including the steps of using the engine operating condition diagram to calculate the vehicle power and so on to achieve the purpose of low-cost dynamic real-time monitoring of vehicle load.

[0010] The technical solution adopted by the present invention is:

[0011] A vehicle load monitoring method for monitoring an engine running audio signal comprises the following steps:

[0012] Step S1, collecting engine audio data through an audio collection device;

[0013] Step S2, analyzing the audio signal of the engine and extracting information about the engine speed, and then calculating the engine speed;

[0014] Step S3, obtaining the output power of the engine at different speeds according to the engine operating condition diagram;

[0015] Step S4: Obtain the speed of the car obtained by the gyroscope, and use the power formula P = F 1 V calculates the wheel driving force F 1 , where P is the output power at the current speed obtained from the operating diagram, and V is the vehicle speed obtained by the gyroscope;

[0016] Step S5: Calculate the longitudinal traction force F exerted on the vehicle during the motion process 11 , the specific calculation formula is:

[0017] F 11 ＝ F 1 -f 1 -f 2 -f 3 ,

[0018] Among them, F 1 is the wheel driving force, f 1 is the road friction resistance of the car, f 2 is the wind resistance of the car, f 3 It is the resistance that the car experiences on the slope due to gravity;

[0019] Step S6: Obtain the acceleration a obtained by the vehicle gyroscope from the gyroscope 1 , based on Newton's second law F 11 =ma 1 The gross vehicle mass m is calculated, and then the vehicle load is obtained by subtracting the vehicle weight from the gross vehicle mass; the vehicle load is compared with the specified load to determine whether the vehicle is overloaded.

[0020] Furthermore, the step S2 is further specifically as follows:

[0021] Step S21, converting the collected engine audio data, i.e., the original analog signal, into a digital signal, and preprocessing the signal using audio processing software to improve the clarity and accuracy of the signal;

[0022] Step S22, performing spectrum analysis on the pre-processed audio signal to find the fundamental frequency in the signal; the fundamental frequency refers to the frequency point corresponding to the peak value in the low frequency area;

[0023] Specifically, in addition to the cylinder movement, other vibrations when the engine is running will produce a series of harmonics, among which the fundamental frequency (lowest frequency) is directly related to the engine speed.

[0024] Step S23: According to the formula n=60×(c / 2)×f base / i, the engine speed is obtained, where n represents the engine speed, c represents the number of engine strokes, and f base represents the fundamental frequency, and i represents the number of cylinders of the engine.

[0025] Furthermore, the audio processing software in step S21 includes Audacity and MATLAB.

[0026] Furthermore, the preprocessing in step S21 includes noise reduction, filtering, etc.

[0027] Furthermore, the step S5 is further specifically as follows:

[0028] Step S51: According to Coulomb's friction law formula f 1 =u 1 Ncosθ is calculated to get f 1 , where N represents the positive pressure, according to the formula N = G + m 1 g; where G is the gravity of the vehicle, which is a known value obtained from the vehicle data manual before departure; m 1 is the weight of the cargo, represents the unknown value to be obtained; g represents the acceleration of gravity, θ is the road slope angle obtained by the gyroscope, and u 1 is the dynamic friction coefficient, and the rotation speed at two moments in adjacent time periods is taken.

[0029] Step S52: According to formula f 1 =ρV 2 u 2 A / 2 calculates f 2 , where ρ is the air density which can be estimated based on the region and temperature, V 2 is the square of the vehicle speed, which can be obtained from the gyroscope; u 2is the drag coefficient of the car, which can be obtained from the official product manual; A is the frontal area of ​​the car, which can be estimated based on the size and shape of the car;

[0030] Step S53: According to formula f 3 =NsinθCalculate f 3 , where N represents the positive pressure, according to the formula N = G + m 1 g is obtained, where G is the gravity of the vehicle, m 1 is the weight of the cargo, g represents the acceleration of gravity, and θ is the road slope angle which can be obtained based on the gyroscope.

[0031] Furthermore, the calculation steps of the dynamic friction coefficient in step S51 are as follows:

[0032] Step S51-1, obtaining the wheel driving force F of the previous time period of the adjacent time period 1 , the corresponding formula is: ①F 1 -u 1 Ncosθ-f 2 -f 3 =ma 1 , f 2 is the wind resistance of the car, f 3 is the resistance of the car on the slope due to gravity; 1 is the acceleration of the previous time period obtained by the gyroscope;

[0033] Step S51-2, obtaining the wheel driving force F of the next time period of the adjacent time period 2 , corresponding to formula F 2 -u 1 Ncosθ-f 2 -f 3 =ma 2 , f 2 is the wind resistance of the car, f 3 is the resistance of the car on the slope due to gravity; 2 is the acceleration of the previous time period obtained by the gyroscope;

[0034] Step S51-3, combine and calculate these two formulas to obtain the dynamic friction coefficient u 1 .

[0035] Furthermore, the value of the air density ρ in step S52 is generally around 1.2 kg / m3.

[0036] The present invention adopts the above technical solution to manage vehicles from the source, and the vehicles can be weighed at any time without location restrictions. Compared with common vehicle-mounted weighing sensors, this device has a better installation environment, lower cost, and more convenient maintenance. The implementation of this technical solution helps to improve road safety, ensure the service life of vehicles, improve the management efficiency of relevant departments and vehicle managers, solve the problem that traffic regulatory departments cannot monitor whether vehicles on ordinary roads are overloaded, maintain the market order of transportation companies, and protect the environment and resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments;

[0038] Figure 1 A flow chart of a vehicle load monitoring method for monitoring an engine operation audio signal according to the present invention;

[0039] Figure 2 is the engine operating diagram;

[0040] Figure 3 This is a diagram of the mechanical model of a car in motion. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0042] like Figures 1 to 3 As shown in one, the present invention discloses a vehicle load monitoring method for monitoring an engine operation audio signal, comprising the following steps:

[0043] Step S1, collecting engine audio data through an audio collection device;

[0044] Step S2, analyzing the audio signal of the engine and extracting information about the engine speed, and then calculating the engine speed;

[0045] Step S3, obtaining the output power of the engine at different speeds according to the engine operating condition diagram;

[0046] Step S4: Obtain the speed of the car obtained by the gyroscope, and use the power formula P = F 1 V calculates the wheel driving force F 1 , where P is the output power at the current speed obtained from the operating diagram, and V is the vehicle speed obtained by the gyroscope;

[0047] Step S5: Calculate the longitudinal traction force F exerted on the vehicle during the motion process 11 , the specific calculation formula is:

[0048] F11 ＝ F 1 -f 1 -f 2 -f 3 ,

[0049] Among them, F 1 is the wheel driving force, f 1 is the road friction resistance of the car, f 2 is the wind resistance of the car, f 3 It is the resistance that the car experiences on the slope due to gravity;

[0050] Step S6: Obtain the acceleration a obtained by the vehicle gyroscope from the gyroscope 1 , based on Newton's second law F 11 =ma 1 The gross vehicle mass m is calculated, and then the vehicle load is obtained by subtracting the vehicle weight from the gross vehicle mass; the vehicle load is compared with the specified load to determine whether the vehicle is overloaded.

[0051] Furthermore, the step S2 is further specifically as follows:

[0052] Step S21, converting the collected engine audio data, i.e., the original analog signal, into a digital signal, and preprocessing the signal using audio processing software to improve the clarity and accuracy of the signal;

[0053] Step S22, performing spectrum analysis on the pre-processed audio signal to find the fundamental frequency in the signal; the fundamental frequency refers to the frequency point corresponding to the peak value in the low frequency area;

[0054] Specifically, in addition to the cylinder movement, other vibrations when the engine is running will produce a series of harmonics, among which the fundamental frequency (lowest frequency) is directly related to the engine speed.

[0055] Step S23: According to the formula n=60×(c / 2)×f base / i, the engine speed is obtained, where n represents the engine speed, c represents the number of engine strokes, and f base represents the fundamental frequency, and i represents the number of cylinders of the engine.

[0056] Furthermore, the audio processing software in step S21 includes Audacity and MATLAB.

[0057] Furthermore, the preprocessing in step S21 includes noise reduction, filtering, etc.

[0058] Furthermore, the step S5 is further specifically as follows:

[0059] Step S51: According to Coulomb's friction law formula f 1 =u1 Ncosθ is calculated to get f 1 , where N represents the positive pressure, according to the formula N = G + m 1 g; where G is the gravity of the vehicle, which is a known value obtained from the vehicle data manual before departure; m 1 is the weight of the cargo, represents the unknown value to be calculated; g represents the acceleration due to gravity, θ is the road slope angle obtained from the gyroscope, u 1 is the dynamic friction coefficient, and the rotation speed at two moments in adjacent time periods is taken.

[0060] Step S52: According to formula f 1 =ρV 2 u 2 A / 2 calculates f 2 , where ρ is the air density which can be estimated based on the region and temperature, V 2 is the square of the vehicle speed, which can be obtained from the gyroscope; u 2 is the drag coefficient of the car, which can be obtained from the official product manual; A is the frontal area of ​​the car, which can be estimated based on the size and shape of the car;

[0061] Step S53: According to formula f 3 =NsinθCalculate f 3 , where N represents the positive pressure, according to the formula N = G + m 1 g is obtained, where G is the gravity of the vehicle, m 1 is the weight of the cargo, g is the acceleration due to gravity, θ The road slope angle can be obtained based on the gyroscope.

[0062] Furthermore, the calculation steps of the dynamic friction coefficient in step S51 are as follows:

[0063] Step S51-1, obtaining the wheel driving force F of the previous time period of the adjacent time period 1 , the corresponding formula is: ①F 1 -u 1 Ncosθ-f 2 -f 3 =ma 1 , f 2 is the wind resistance of the car, f 3 is the resistance of the car on the slope due to gravity; 1 is the acceleration of the previous time period obtained by the gyroscope;

[0064] Step S51-2, obtaining the wheel driving force F of the next time period of the adjacent time period 2 , corresponding to formula F 2 -u 1 Ncosθ-f2 -f 3 =ma 2 , f 2 is the wind resistance of the car, f 3 is the resistance of the car on the slope due to gravity; 2 is the acceleration of the previous time period obtained by the gyroscope;

[0065] Step S51-3, combine and calculate these two formulas to obtain the dynamic friction coefficient u 1 .

[0066] Furthermore, the value of the air density ρ in step S52 is generally around 1.2 kg / m3.

[0067] The present invention adopts the above technical solution to manage vehicles from the source, and the vehicles can be weighed at any time without location restrictions. Compared with common vehicle-mounted weighing sensors, this device has a better installation environment, lower cost, and more convenient maintenance. The implementation of this technical solution helps to improve road safety, ensure the service life of vehicles, improve the management efficiency of relevant departments and vehicle managers, solve the problem that traffic regulatory departments cannot monitor whether vehicles on ordinary roads are overloaded, maintain the market order of transportation companies, and protect the environment and resources.

[0068] Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians of the art without making creative work are within the scope of protection of the present application.

Claims

1. A vehicle load monitoring method by monitoring the audio signal of engine operation, characterized in that: It includes the following steps: Step S1, collecting engine audio data through an audio collection device; Step S2, analyzing the audio signal of the engine and extracting information about the engine speed, and then calculating the engine speed; Step S3, obtaining the output power of the engine at different speeds according to the engine operating condition diagram; Step S4, obtaining the driving speed of the car obtained by the gyroscope, and calculating the wheel driving force F1 according to the power formula P=F1V, wherein P is the output power at the current speed obtained from the working condition diagram, and V is the driving speed of the car obtained by the gyroscope; Step S5: Calculate the longitudinal traction F exerted on the vehicle during the motion process 11 , the specific calculation formula is: <h2 style=";text-align:left;direction:ltr">F<h2 style=";text-align:left;direction:ltr"> 11 <h2 style=";text-align:left;direction:ltr"> (F1-f1-f2-f3) Among them, F1 is the wheel driving force, f1 is the road friction resistance of the car, f2 is the wind resistance of the car, and f3 is the resistance of the car on the slope due to gravity; Step S6: Obtain the acceleration a1 obtained by the vehicle gyroscope from the gyroscope, based on Newton's second law F 11 =ma1 to calculate the total vehicle mass m, and then subtract the vehicle weight from the total vehicle mass to get the vehicle load; compare the vehicle load with the specified load to determine whether the vehicle is overloaded.

2. A vehicle load monitoring method for monitoring engine operation audio signals according to claim 1, characterized in that: The step S2 is further specifically as follows: Step S21, converting the collected engine audio data, i.e., the original analog signal, into a digital signal, and preprocessing the signal using audio processing software to improve the clarity and accuracy of the signal; Step S22, performing spectrum analysis on the pre-processed audio signal to find the fundamental frequency in the signal; the fundamental frequency refers to the frequency point corresponding to the peak value in the low frequency area; Step S23: According to the formula n=60×(c / 2)×f base / i, the engine speed is obtained, where n represents the engine speed, c represents the number of engine strokes, and f base represents the fundamental frequency, and i represents the number of cylinders of the engine.

3. A vehicle load monitoring method for monitoring engine operation audio signals according to claim 2, characterized in that: The audio processing software in step S21 includes Audacity and MATLAB.

4. The vehicle load monitoring method of monitoring the engine operation audio signal according to claim 2, characterized in that: The preprocessing in step S21 includes noise reduction, filtering, etc.

5. The vehicle load monitoring method of monitoring the engine operation audio signal according to claim 1, characterized in that: The specific steps of step S5 are: Step S51, f1 is calculated according to the Coulomb friction law formula f1=u1Ncosθ, where N represents the positive pressure, which is obtained according to the formula N=G+m1g; where G is the gravity of the vehicle, which is a known value obtained from the vehicle data manual before departure; m1 is the weight of the cargo, which represents the unknown value to be obtained; g represents the acceleration of gravity, θ is the road slope angle obtained from the gyroscope, u1 is the dynamic friction coefficient, and the rotation speed at two moments in adjacent time periods is taken. Step S52: According to the formula f1=ρV 2 f2 is calculated from u2A / 2, where ρ is the air density which can be estimated based on the region and temperature, V 2 is the square of the vehicle speed, which can be obtained from the gyroscope; u2 is the vehicle drag coefficient, which can be obtained from the official product manual; A is the frontal area of ​​the vehicle, which can be estimated based on the size and shape of the vehicle; Step S53, f3 is calculated according to the formula f3=nsinθ, where N represents the positive pressure, and is obtained according to the formula N=G+m1g, where G is the gravity of the vehicle, m1 is the weight of the cargo, g represents the acceleration of gravity, and θ is the road slope angle which can be obtained according to the gyroscope.

6. The vehicle load monitoring method of monitoring the engine operation audio signal according to claim 5, characterized in that: The calculation steps of the dynamic friction coefficient in step S51 are as follows: Step S51-1, obtaining the wheel driving force F1 of the previous time period of the adjacent time period, the corresponding formula is: ① F1-u1Ncosθ-f2-f3=ma1, f2 is the wind resistance of the car, f3 is the resistance of the car on the slope due to gravity; a1 is the acceleration of the previous time period obtained by the gyroscope; Step S51-2, obtaining the wheel driving force F2 of the next time period of the adjacent time period, corresponding to the formula F2-u1Ncosθ-f2-f3=ma2, f2 is the wind resistance of the car, f3 is the resistance of the car on the slope due to gravity; a2 is the acceleration of the previous time period obtained by the gyroscope; Step S51 - 3 , the dynamic friction coefficient u1 can be obtained by combining and calculating these two formulas.

7. The vehicle load monitoring method of monitoring the engine operation audio signal according to claim 5, characterized in that: The value of the air density ρ in step S52 is generally around 1.2 kg / m3.

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