A method for simulating a radiation noise signal of a motion state quad-rotor unmanned aerial vehicle

Abstract

The application provides a method for simulating a radiation noise signal of a four-rotor unmanned aerial vehicle in a motion state, which comprises the following steps: setting a motion state and basic parameters of a multi-rotor unmanned aerial vehicle to be simulated; setting signal simulation parameters of the four-rotor unmanned aerial vehicle to be simulated; generating a rotation frequency sequence of each rotor propeller in a hovering state and an intensity sequence of each harmonic signal according to the motion state, the basic parameters and the signal simulation parameters of the four-rotor unmanned aerial vehicle; correcting the rotation frequency sequence of each rotor propeller according to the motion state and the basic parameters of the four-rotor unmanned aerial vehicle; generating a radiation signal waveform of each rotor propeller in a maneuvering state according to the signal simulation parameters, the rotation frequency sequence of each rotor propeller and the intensity sequence of each harmonic signal; and superimposing the radiation signal waveforms of each rotor propeller in the maneuvering state to obtain a radiation noise signal of the four-rotor unmanned aerial vehicle.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of unmanned aerial vehicle acoustic characteristic simulation and signal processing, and particularly relates to a kind of motion state four rotor unmanned aerial vehicle radiation noise signal simulation method. BACKGROUND

[0002] Multi-rotor unmanned aerial vehicles produce unique acoustic characteristic signals during flight. These noises mainly come from the aerodynamic noise of the rotors, the high-frequency electromagnetic noise of the motors, and the mechanical vibration noise of the airframe. They are important basis for acoustic detection equipment to identify and track unmanned aerial vehicle targets. Due to the differences in the number of unmanned aerial vehicle rotors and environmental interference, the radiation noise characteristics are different. It is difficult to obtain noise signals with good diversity and controllable parameters directly through real unmanned aerial vehicle flight tests.

[0003] Currently, acoustic simulation technology based on signal modeling has been gradually applied in the field of unmanned aerial vehicle target detection. By analyzing the correlation between rotor rotation frequency and harmonic distribution, and the broadband characteristics of motor noise, researchers can construct a parameterized unmanned aerial vehicle noise model. Such simulated signals have been used in acoustic fingerprint database construction, target classification algorithm training, and detection equipment performance evaluation, and have shown important value in the fields of smart security and military defense.

[0004] Existing unmanned aerial vehicle noise simulation methods still have obvious limitations. For example, the existing unmanned aerial vehicle simulation method does not simulate the differences in the frequencies of the rotors in the propeller well enough, making it difficult to produce realistic signals. In the existing motion unmanned aerial vehicle audio synthesis method, the frequency change curve of each rotor of the unmanned aerial vehicle is considered to be the same, without considering the frequency differences between the rotors. Therefore, it is urgent to develop an unmanned aerial vehicle noise simulation system that supports multi-rotor asynchronous frequency coupling modeling, dynamic harmonic superposition, and high-precision propagation and attenuation simulation. SUMMARY

[0005] To overcome the defects of existing four-rotor unmanned aerial vehicle noise simulation technology in comprehensiveness and authenticity, the present application proposes a motion state four-rotor unmanned aerial vehicle radiation noise signal simulation method.

[0006] TECHNICAL SOLUTION To solve the above technical problems and achieve the above application purposes, the present application provides a motion state four-rotor unmanned aerial vehicle radiation noise signal simulation method, which specifically includes the following steps:

[0007] Step 1: Set the motion state and basic parameters of the four-rotor unmanned aerial vehicle to be simulated;

[0008] Step 2: Set the signal simulation parameters of the four-rotor unmanned aerial vehicle to be simulated;

[0009] Step 3: Based on the maneuvering state, basic parameters, and signal simulation parameters of the quadcopter UAV, generate the rotation frequency sequence of each rotor propeller in the hovering state and the intensity sequence of each harmonic signal in sequence.

[0010] Step 4: Adjust the rotation frequency sequence of each rotor propeller according to the maneuvering state and basic parameters of the quadcopter UAV. If the UAV is in a hovering state, skip step 4.

[0011] Step 5: Based on the signal simulation parameters, the rotation frequency sequence of each rotor propeller, and the intensity sequence of each harmonic signal, generate the radiation signal waveform of the quadcopter propeller in the maneuvering state in sequence.

[0012] Step 6: Superimpose the radiation signal waveforms of each rotor propeller in the maneuvering state generated in Step 5 to obtain the radiated noise signal of the quadcopter UAV.

[0013] Furthermore, the motion states of the quadcopter UAV include hovering, vertical ascent, vertical descent, pitch, horizontal movement, and yaw motion, as well as the start time of the motion. End time of exercise and state transition time ,satisfy .

[0014] Furthermore, the basic parameters of the quadcopter drone include the average rotation frequency of the rotor propellers in hovering state. Rotor frequency fluctuation value .

[0015] Furthermore, the signal simulation parameters include harmonic orders. Sampling rate Total duration ,in, .

[0016] Furthermore, the specific steps for step 3 are as follows:

[0017] Generate the first The propeller at the sampling time Rotation frequency sequence ,in, are integers and satisfy The generation method is as follows:

[0018] make When there is When the absolute value generated is less than random variable ϵ;

[0019]

[0020] in, ;

[0021] Setting the first harmonic signal strength sequence , wherein is a non-negative real number, .

[0022] Further, the specific method in step 4 is as follows:

[0023] Calculate the sampling time Correct the frequency :

[0024]

[0025] According to the set unmanned aerial vehicle motion state, the rotation frequency is corrected according to the following rules:

[0026] When the unmanned aerial vehicle is vertically ascending:

[0027]

[0028] When the unmanned aerial vehicle is vertically descending:

[0029]

[0030] When the unmanned aerial vehicle is pitching:

[0031]

[0032] When the unmanned aerial vehicle is horizontally moving:

[0033]

[0034] When the unmanned aerial vehicle is yawing:

[0035]

[0036] .

[0037] Further, the specific method of step 5 is as follows:

[0038] Calculate the time first harmonic signal , the specific method is as follows:

[0039]

[0040]

[0041] Generate time first Subharmonic signals The calculation formula is as follows:

[0042]

[0043] All harmonic signals are linearly superimposed to generate a single propeller signal. as follows:

[0044]

[0045] in, Indicates the first propeller Synthesized signal at time, based on signal The radiation signal waveforms of each rotor propeller under a given state are generated sequentially.

[0046] Furthermore, the specific method for step 6 is as follows:

[0047]

[0048] in, express Synthesized signal at time.

[0049] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0050] (1) When simulating the radiated noise of a quadcopter drone in motion, the environmental noise in the complex environment often changes. This invention can not only simulate the subtle differences in the rotation frequency between rotors, but also adjust the environmental noise spectrum level to correspond to the environmental noise, so that the complex environmental noise simulated in the radiated noise simulation of a quadcopter drone in motion is more comprehensive.

[0051] (2) The present invention fully considers the dynamic characteristics of the target. Through parametric modeling and signal superposition technology, the simulated UAV noise basically conforms to the noise signal radiated by the actual target when it moves.

[0052] (3) This invention realizes a method for simulating the noise signal of a quadcopter UAV in motion with high fidelity, providing high fidelity data for the study and testing of the acoustic characteristics of UAVs. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments are briefly described below.

[0054] Figure 1 This is a flowchart of a method for simulating radiated noise signals of a quadcopter drone in motion, according to the present invention.

[0055] Figure 2 It is the frequency curve of the noise simulation signal of a quadcopter drone in a vertical upward motion state.

[0056] Figure 3 It is the radiation waveform signal of the noise simulation signal of a quadcopter drone in the vertical upward motion state. Detailed Implementation

[0057] To more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0058] like Figure 1 As shown, this invention proposes a method for simulating radiated noise signals of a quadcopter unmanned aerial vehicle in motion. The method includes the following steps:

[0059] Step 1. Set the maneuvering states and basic parameters of the quadcopter drone to be simulated. The quadcopter drone's motion states include hovering, vertical ascent, vertical descent, pitch, horizontal movement, and yaw, as well as the start time of each motion. End time of exercise and state transition time ,satisfy The basic parameters of a quadcopter drone include the average rotational frequency of the rotor propellers in hovering state. Rotor frequency fluctuation value .

[0060] Step 2. Set the signal simulation parameters for the quadcopter drone to be simulated; whereby the signal simulation parameters include harmonic orders. Sampling rate Total duration ,in, The initial values ​​of the parameters are set according to the requirements of the radiated noise signal to be simulated and the environmental characteristics. The change of the initial values ​​of the parameters indicates the change of the noise of the UAV to be simulated.

[0061] Step 3. Based on the maneuvering state, basic parameters, and signal simulation parameters of the quadcopter UAV, generate the rotation frequency sequence of each rotor propeller in the hovering state and the intensity sequence of each harmonic signal in sequence.

[0062] Generate the first The propeller at the sampling time Rotation frequency sequence ,in, is an integer and satisfies , the generating method is as follows:

[0063] Let When there is , generate a random variable with an absolute value less than

[0064]

[0065] wherein ;

[0066] Set the strength sequence of the first harmonic signal , wherein is a non-negative real number, . This example is:

[0067]

[0068] is the average rotational frequency amplitude, and here .

[0069]

[0070] Step 4. According to the maneuvering state and basic parameters of the quadcopter, correct the rotor propeller rotation frequency sequence. If the motion state of the unmanned aerial vehicle is hovering, skip, otherwise correct the rotor propeller rotation frequency sequence, the method is as follows:

[0071] Calculate the sampling time Correct the frequency , the formula is

[0072]

[0073] According to the set motion state of the unmanned aerial vehicle, correct the rotation frequency according to the following rules,

[0074] When the unmanned aerial vehicle is vertically ascending, ;

[0075] When the unmanned aerial vehicle is vertically descending, ;

[0076] When the unmanned aerial vehicle is in pitch motion, ;

[0077] When the unmanned aerial vehicle is in horizontal motion, ;

[0078] When the unmanned aerial vehicle is in yaw motion,

[0079] ;

[0080] The embodiment takes vertical rising as an example.

[0081] Step 5. According to the signal simulation parameters, the rotation frequency sequence of each rotor propeller and the sequence of the harmonic signal intensity, the radiation signal waveform of the quad-rotor propeller in a given state is generated in sequence; the specific method is as follows:

[0082] The first harmonic signal is calculated The phase of each time is calculated, and the formula is as follows:

[0083]

[0084] The first harmonic signal at time t is generated , and the calculation formula is as follows:

[0085]

[0086]

[0087] All harmonic signals are linearly superimposed to generate a single propeller signal , and all propeller signals are summed to obtain :

[0088]

[0089] Step 6. The radiation signal waveforms of each rotor propeller in a given motion state generated in step 5 are superimposed to obtain the radiation noise signal of the quad-rotor unmanned aerial vehicle, and the formula is as follows:

[0090]

[0091] As shown in Figure 2 , it shows the frequency curve of the quad-rotor unmanned aerial vehicle noise simulation signal in the vertical rising motion state, and as shown in Figure 3 , it shows the radiation waveform signal of the quad-rotor unmanned aerial vehicle noise simulation signal in the vertical rising motion state.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limited. Although the present application has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and they should be covered in the scope of the claims of the present application.​​​

Claims

1. A method for simulating a radiation noise signal of a motion state quadrotor unmanned aerial vehicle, characterized in that, The method specifically comprises: Step 1, setting the maneuvering state and basic parameters of the quad-rotor unmanned aerial vehicle to be simulated; Step 2, setting the signal simulation parameters of the quad-rotor unmanned aerial vehicle to be simulated; Step 3, generating the rotation frequency sequence of the hovering state of each rotor propeller and the intensity sequence of each harmonic signal according to the maneuvering state, basic parameters and signal simulation parameters of the quad-rotor unmanned aerial vehicle; Step 4, correcting the rotation frequency sequence of each rotor propeller according to the maneuvering state and basic parameters of the quad-rotor unmanned aerial vehicle, and if the motion state of the unmanned aerial vehicle is the hovering state, skipping step 4; Step 5, generating the radiation signal waveform of each rotor propeller in the maneuvering state according to the signal simulation parameters, the rotation frequency sequence of each rotor propeller and the intensity sequence of each harmonic signal; Step 6, superimposing the radiation signal waveforms of each rotor propeller in the maneuvering state generated in step 5 to obtain the radiation noise signal of the quad-rotor unmanned aerial vehicle; In step 1, the motion state of the quadrotor includes the motion type of hovering, vertical ascending, vertical descending, pitching, horizontal motion and yawing, and the motion start time , the motion end time and the state transition time , satisfying ; the basic parameters of the quadrotor include the average rotation frequency of the rotor propeller in the hovering state , and the rotor propeller rotation frequency fluctuation value ; In step 2, the signal simulation parameters include the harmonic number , the sampling rate , the total duration , wherein ; The specific method in step 3 is as follows: The first propeller is generated at the rotation frequency sequence of the propeller at the sampling time , wherein, is an integer and satisfies The generating method is as follows: Let When there is an absolute value less than a random variable ϵ; wherein ; Setting the first sequence of intensities of the second harmonic signal wherein, is a non-negative real number, ; The specific method in step 4 is as follows: Computing the sampling instants Correcting the frequency : According to the set unmanned aerial vehicle motion state, the rotation frequency is corrected according to the following rules Amendments: When the unmanned aerial vehicle is vertically ascending: When the unmanned aerial vehicle is vertically descending: When the unmanned aerial vehicle is pitching: When the unmanned aerial vehicle is horizontally moving: When the unmanned aerial vehicle is yawing: 。 2. The method of claim 1, wherein, The specific method in step 5 is as follows: Calculations Time instant Subharmonic signal The specific method is as follows: generated at a time subharmonic signal The calculation formula is as follows: All harmonic signals linearly superimposed to generate single propeller signal As follows: wherein, represents the th propeller synthesis signal at the moment, according to the signals radiation signal waveforms of each rotor propeller in a given state are generated in sequence.

3. The method of claim 2, wherein, The specific method in step 6 is as follows: wherein represents the composite signal at the moment in time.

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