EVTOL vertical takeoff and landing site selection decision method based on noise propagation mechanism

Abstract

The invention discloses an EVTOL vertical takeoff and landing site selection decision-making method based on a noise propagation mechanism. The method comprises the following steps: S1, determining an environment noise limit value of a building surface corresponding to each building in an urban area; s2, constructing a noise limit value contour surface spatial distribution model of the single building; s3, calculating to obtain a noise limit value contour surface spatial distribution model of various buildings in the urban area; s4, determining whether the candidate point positions meet noise requirements on the ground plane or not; s6, determining an EVTOL aircraft running track xi; and S7, checking whether the candidate point positions meet the noise requirement of the space operation process or not, and finally determining the site selection of the vertical take-off and landing field.

Description

Technical Field

[0001] The present invention belongs to the field of vertical takeoff and landing airport site selection decision-making, and particularly relates to a method for selecting a site for an EVTOL vertical takeoff and landing field based on a noise propagation mechanism. Background Art

[0002] Aviation noise has been proven to potentially cause many negative impacts on human health, including annoyance, sleep disorders, hearing loss, cardiovascular problems, and impaired cognitive function. In addition to the health effects, aviation noise also has a negative impact on property values and quality of life. Therefore, the noise factor is an important consideration when selecting an airport site.

[0003] As an important part of the emerging urban air mobility (UAM) ecosystem, the vertical takeoff and landing airport provides necessary facilities such as takeoff, landing, and touchdown points for electrically driven vertical takeoff and landing (EVTOL) aircraft. The vertical takeoff and landing airport is expected to serve more in cities and their suburbs, which means that the vertical takeoff and landing airport will be close to residential, commercial, and other crowded spaces in the city. Although the noise generated by EVTOL aircraft during takeoff, landing, and flight is significantly lower than that of conventional civilian aircraft and is expected to achieve a quieter operating environment, it may still have an adverse impact on the daily lives of nearby community residents. In addition, currently, both at home and abroad, the site selection methods for vertical takeoff and landing fields mostly draw on those for general airports, and the influencing factors mainly focus on aspects such as meteorological land conditions, meteorological conditions, and clearance conditions, lacking research on the site selection of vertical takeoff and landing fields from the perspective of noise impact.

[0004] Therefore, in order to reduce the impact of the noise generated by EVTOL vertical takeoff and landing fields on urban residents, achieve the harmonious coexistence of eVTOL aircraft and urban residents, and improve the site selection decision-making method for EVTOL vertical takeoff and landing fields, it is necessary to study the site selection strategy for EVTOL vertical takeoff and landing fields based on the noise propagation mechanism. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for selecting a site for an EVTOL vertical takeoff and landing field based on a noise propagation mechanism, and to determine the site selection decision-making method for an EVTOL vertical takeoff and landing field in urban space by analyzing the noise tolerance of various types of land uses and the noise propagation characteristics of EVTOL aircraft.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] A method for selecting a site for an EVTOL vertical takeoff and landing field based on a noise propagation mechanism, comprising the following steps:

[0008] S1. Determine the environmental noise limit values of the building surfaces corresponding to each building in the urban area based on the acoustic environment functional zoning corresponding to different land use types

[0009] S2. Based on the outdoor noise propagation attenuation mechanism, construct a spatial distribution model of the noise limit contour surface for a single building;

[0010] S3. Calculate and obtain the spatial distribution models of the noise limit contour surfaces for various buildings in the urban area, take the union of the intersecting contour surfaces with the same noise limit values for each building, and construct the overall building noise limit contour surface Ω of the urban area;

[0011] S4. Determine the candidate vertical takeoff and landing site points P according to the spatial distribution of the overall building noise limit contour surface Ω and the land use type distribution in the urban area m , m = 1, 2, 3…,;

[0012] S5. By comparing the noise value L when the noise of the EVTOL aircraft in the waiting - to - fly state propagates to a certain noise limit surface Ω at the candidate point m with the noise limit value evtol corresponding to the noise limit surface Ω m to determine whether the candidate point meets the noise requirements on the ground plane;

[0013] S6. Comprehensively consider the hovering height, approach / take - off climb surface slope, and different approach / take - off climb surface angle parameter requirements during the vertical takeoff and landing stage and the approach / take - off climb stage of the EVTOL aircraft to determine its flight path ξ;

[0014] S7. By comparing the noise value L when the noise of the EVTOL aircraft during its flight along the flight path ξ propagates to a certain noise limit surface Ω k with the noise limit value evtol corresponding to this noise limit surface Ω k to check whether the candidate point meets the noise requirements during the spatial operation process, and finally determine the vertical takeoff and landing site location.

[0015] Further, step S1 includes the following steps:

[0016] S101. Determine the corresponding acoustic environment functional zoning based on the land use type of building j, obtain the corresponding equivalent continuous A - weighted sound level limit value therefrom, and use this as the environmental noise limit value of the surface of building j where n is the number of buildings in the urban area.

[0017] Further, step S2 includes the following steps:

[0018] S201. Based on the scope of the urban area under study, select a coordinate origin on the geoid, use the due north direction as the Y-axis, the due east direction as the X-axis, and the upward direction perpendicular to the geoid as the Z-axis to establish a coordinate system;

[0019] S202. Perform grid processing on the outer surface of building j to obtain the three-dimensional spatial coordinates p i (x, y, z), where i = 1, 2, 3…;

[0020] S203. Based on the outdoor noise propagation attenuation mechanism, construct the noise limit value of the point q i (x, y, z) at a vertical distance of r from the grid point p i (x, y, z) on the outer surface of the building; The calculation formula;

[0021] S204. Perform three-dimensional surface fitting on the spatial points q limit with the same noise limit value L i (r), where i = 1, 2, 3…, to obtain the noise limit surface corresponding to building j under this noise limit value. The noise limit surfaces together constitute the spatial distribution model of the noise limit contour surface of a single building j.

[0022] Furthermore, the calculation formula based on the outdoor noise propagation attenuation mechanism in step S203 is specifically as follows:

[0023]

[0024] In the formula: is the environmental noise limit value on the surface of building j; A div is the attenuation caused by geometric divergence; A atm is the attenuation caused by atmospheric absorption; A gr is the attenuation caused by ground effect; A misc is the attenuation caused by other multi-faceted effects;

[0025] The calculation formulas for each noise propagation attenuation term are as follows:

[0026] A div = 20lg(r0 / (r0 - r)) (14)

[0027] In the formula: A div is the attenuation caused by geometric divergence, dB; r0 is the distance from the point (x, y, z) on the building surface to the sound source, m; r is the vertical distance, m;

[0028]

[0029] In the formula: A atmA is the attenuation caused by atmospheric absorption, in dB; α is the atmospheric absorption attenuation coefficient related to temperature, humidity and acoustic wave frequency;

[0030]

[0031] In the formula: A gr is the attenuation caused by ground effect, in dB; h m is the average height from the ground of the propagation path, in m; r0 is the distance from the point (x, y, z) on the building surface to the sound source, in m;

[0032] The attenuation A caused by other various effects misc includes the attenuation A caused by greening forest belts fol and the noise attenuation A of the building complex hous ; among them, A fol is considered according to the vegetation type and forest belt length factors in the actual environment; A hous The specific calculation formula is as follows:

[0033] A hous = 0.1Bd0 - 10lg(1 - p) (17)

[0034] In the formula: B is the density of the buildings along the sound propagation route; d0 is the length of the sound propagation route passing through the building complex, in m; p is the total length of the fronts of the buildings longitudinally distributed along the sound source divided by the corresponding length of the sound source.

[0035] Furthermore, step S3 includes the following steps:

[0036] S301. Based on the spatial distribution model of the noise limit contour surface of a single building, calculate the noise limit contour surface Ω corresponding to building j in the urban area respectively j , j = 1, 2,..., n;

[0037] S302. In each building noise limit contour surface, the noise limit surfaces corresponding to the same noise limit together form the overall building noise limit surface of the urban area under this noise limit If the noise limit surfaces of each building under the same noise limit intersect, take the union as the overall building noise limit surface;

[0038] S303. Each noise limit surface together constitutes the overall building noise limit contour surface Ω of the urban area.

[0039] Furthermore, step S4 includes the following steps:

[0040] S401. Denote the ground plane of the research area as a horizontal plane β, and the intersection of plane β and the building noise limit contour surface Ω obtains the distribution of the building noise limit horizontal contour lines of the overall urban area;

[0041] S402. Select the area outside a certain noise limit contour line in the contour line distribution of the building noise limit horizontal plane as the candidate area for the EVTOL vertical takeoff and landing site;

[0042] S403. Determine the candidate point P of the vertical takeoff and landing site in combination with the distribution of different land use types in the candidate area m , m = 1, 2, 3….

[0043] Further, step S5 includes the following steps:

[0044] S501. Based on the operating characteristics of the EVTOL aircraft in the pre-flight state, determine that the aircraft pre-flight state noise value is

[0045] S502. Select a certain candidate point P m , at P m , calculate the aircraft noise propagating to a certain noise limit surface Ω m when the noise value L evtol , and judge the size relationship between the aircraft noise value L evtol and the noise limit corresponding to this noise limit surface Ω m ; between;

[0046] Among them, the aircraft noise propagating to a certain noise limit surface Ω m when the noise value L evtol is calculated as follows:

[0047]

[0048] In the formula: A div is the attenuation caused by geometric divergence; A atm is the attenuation caused by atmospheric absorption; A gr is the attenuation caused by ground effect; A misc is the attenuation caused by other various effects; the calculation formula of the attenuation term is the same as that in step S204;

[0049] The calculation formulas of each noise propagation attenuation term are as follows:

[0050]

[0051] In the formula: A div is the attenuation caused by geometric divergence, dB; d is the distance between the aircraft and the noise limit surface;

[0052]

[0053] In the formula: A atmA is the attenuation caused by atmospheric absorption, in dB; α is the atmospheric absorption attenuation coefficient related to temperature, humidity and acoustic wave frequency; d is the distance between the aircraft and the noise limit surface;

[0054]

[0055] In the formula: A gr is the attenuation caused by ground effect, in dB; h m is the average height above the ground of the propagation path; d is the distance between the aircraft and the noise limit surface;

[0056] The attenuation A caused by other multi-faceted effects misc includes the attenuation A caused by greening forest belts fol and the noise attenuation A of building clusters hous ; among them, A fol needs to be considered according to the vegetation type and forest belt length factors in the actual environment; A hous The specific calculation formula is as follows:

[0057] A hous = 0.1Bd0 - 10lg(1 - p) (22)

[0058] In the formula: B is the density of buildings along the sound propagation route; d0 is the length of the sound propagation route passing through the building cluster; p is the total length of the fronts of buildings longitudinally distributed along the sound source divided by the corresponding sound source length;

[0059] S503. If indicates that the candidate point P m does not meet the building noise limit requirements in the waiting flight state of the EVTOL aircraft, this candidate point is excluded; a new candidate point is selected and go back to step S5, and verify in turn whether the aircraft meets the building noise limit requirements when operating at the candidate point; if indicates that the candidate point P m meets the building noise limit requirements in the waiting flight state of the EVTOL aircraft, further execute step S6 to verify whether it meets the building noise limit requirements during the operation of the aircraft.

[0060] Furthermore, step S6 includes the following steps:

[0061] S601. According to the differences in the operating characteristics of the EVTOL aircraft during the vertical takeoff and landing phase and the approach / takeoff climb phase during operation, determine the hover height at the transition of the two phases, denoted as h0; determine the approach / takeoff climb angle, denoted as α, then the slope of the approach / takeoff climb surface is expressed as tan(α);

[0062] S602. The flight trajectory ξ of the EVTOL aircraft consists of the vertical takeoff and landing center line in the vertical takeoff and landing stage and the approach / takeoff climb surface center line in the approach / takeoff climb stage; let the coordinates during the operation of the EVTOL aircraft be (x evtol , y evtol , z evtol ), and the candidate point P of the vertical takeoff and landing site m has coordinates Then its flight trajectory ξ is specifically expressed as:

[0063] Vertical takeoff and landing process:

[0064]

[0065] In the formula, h0 is the hover height at the transition between the two stages of the EVTOL aircraft's operation;

[0066] Approach / takeoff climb stage:

[0067]

[0068] In the formula, ΔD is a certain length of the EVTOL aircraft flying along the approach / takeoff climb surface center line; α is the approach / takeoff climb angle of the aircraft; β is the angle between the projection of the approach / takeoff climb surface center line on the ground plane and the x-axis; if there are two or more approach / takeoff climb surfaces in the vertical takeoff and landing site, the trajectory of the EVTOL aircraft running along a certain approach / takeoff climb surface can be calculated by formula (7).

[0069] Furthermore, step S7 includes the following steps:

[0070] S701. Based on the noise characteristics of the EVTOL aircraft's flight state, determine that the aircraft flight state noise value is

[0071] S702. Calculate the noise value L k when the noise of the aircraft propagates to a certain noise limit surface Ω evtol during its operation along the trajectory ξ, and judge the magnitude relationship between the aircraft noise value L evtol and the corresponding noise limit k of this noise limit surface Ω ;

[0072] S703. If it indicates that this candidate point P m does not meet the building noise limit requirements during the flight of the EVTOL aircraft, exclude this candidate point; select a new candidate point and go back to step S5 to verify in turn whether the aircraft meets the building noise limit requirements when operating at the candidate point; if it indicates that this candidate point P mMeet the building noise limit requirements during the pre-flight state and flight process of the EVTOL aircraft, and can be used as a site selection point for vertical takeoff and landing fields in urban areas based on building noise limit conditions; select a new candidate point and return to step S5 to verify whether the aircraft meets the building noise limit requirements when operating at the candidate point in turn.

[0073] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the EVTOL vertical takeoff and landing field site selection decision method based on the noise propagation mechanism are implemented.

[0074] Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

[0075] 1. Precise noise prediction and control: By setting building noise limits according to the acoustic environment functional zoning of different land use types, a more accurate basis is provided for the calculation of the building noise limit surface. This method can not only better control the noise source, but also accurately predict the impact of noise on various buildings in the city, thereby effectively reducing noise interference.

[0076] 2. Visual noise impact analysis: By constructing a spatial distribution model of the noise limit contour surface of a single building and combining the noise limits of multiple buildings in the urban area, the overall building noise limit contour surface is formed by the surface fitting method, providing a new visual and quantitative analysis tool to help intuitively evaluate the impact of noise on different buildings.

[0077] 3. Optimized site selection decision: This method compares the noise propagation of the EVTOL aircraft at different candidate points, and scientifically selects the vertical takeoff and landing field points that meet the noise requirements based on the relationship between noise propagation and the noise limit surface. This not only ensures that the site selection meets the technical and noise requirements of the EVTOL aircraft, but also avoids potential problems of setting up vertical takeoff and landing fields in noise-sensitive areas.

[0078] 4. Comprehensive consideration of the noise during the flight of the aircraft: This method not only considers the noise propagation of the EVTOL aircraft in the pre-flight state, but also considers the noise characteristics during its vertical takeoff and landing phase and approach / takeoff climb phase, comprehensively evaluating the noise impact of its entire flight process on the surrounding building environment, so as to avoid site selection mistakes caused by only considering the noise in some flight phases during actual site selection.

[0079] 5. More in line with the requirements of urban noise management: This site selection method can ensure that the selected vertical takeoff and landing site not only meets the operating requirements of EVTOL technology but also satisfies the requirements for limiting the noise of the urban regional building environment. This makes the layout of vertical takeoff and landing sites in urban areas more reasonable, avoiding the negative impact on the quality of residents' lives caused by excessive noise, and promoting the harmonious coexistence of EVTOL aircraft and urban residents.

[0080] In summary, the site selection decision-making method of the present invention has high efficiency, accuracy, can effectively control the noise impact, meets the requirements of modern urban noise management, and provides scientific and feasible decision-making support for the site selection of EVTOL vertical takeoff and landing sites. Brief Description of the Drawings

[0081] Figure 1 It is a flow chart of the site selection of EVTOL vertical takeoff and landing sites based on the noise propagation mechanism of the present invention.

[0082] Figure 2 It is a schematic diagram of the spatial distribution model of the equal-height surface of the noise limit of a single building of the present invention.

[0083] Figure 3 It is a schematic diagram of the site selection of vertical takeoff and landing sites based on the noise of the EVTOL aircraft in the waiting-to-take-off state of the present invention.

[0084] Figure 4 It is a schematic diagram of the flight trajectory of the EVTOL aircraft of the present invention.

[0085] Figure 5 It is a schematic diagram of the site selection of vertical takeoff and landing sites based on the noise of the EVTOL aircraft in the operating state of the present invention.

[0086] Figure 6 It is a schematic diagram of the relationship between the candidate site points and the final selected site area of the vertical takeoff and landing site of the present invention. Detailed Embodiment

[0087] The following further describes the present invention in detail with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0088] The rise of the low-altitude economy concept has promoted the rapid development of urban low-altitude transportation. The site selection of vertical takeoff and landing sites serving vertical takeoff and landing aircraft has become particularly important. At the same time, the restrictions on noise in urban land use and the requirements of urban residents for the noise of the living environment have put forward new requirements for the site selection of vertical takeoff and landing sites.

[0089] See Figure 1 , this embodiment provides a site selection decision-making method for vertical takeoff and landing aircraft (EVTOL) vertical takeoff and landing sites based on the noise propagation mechanism, specifically including the following steps:

[0090] S1. Determine the environmental noise limit values of the building surfaces corresponding to each building in the urban area based on the acoustic environmental function zoning corresponding to different land use types

[0091] S101. Determine the corresponding acoustic environmental function zoning based on the land use type of building j (j = 1, 2, …, n), obtain the corresponding equivalent continuous A-weighted sound pressure level limit value therefrom, and take this as the environmental noise limit value of the surface of building j (j = 1, 2, …, n) Where n is the number of buildings in the urban area.

[0092] Referring to the "Technical Specification for Acoustic Environmental Function Zoning" (GBT15190-2014), according to the usage function characteristics and environmental quality requirements of the area, the acoustic environmental function zones can be divided into the following five types:

[0093] (1) Class 0 acoustic environmental function zone: Refers to special quiet areas such as rehabilitation and convalescence areas.

[0094] (2) Class 1 acoustic environmental function zone: Refers to areas mainly with functions of residential houses, medical and health care, culture and education, scientific research and design, and administrative offices, which need to maintain quietness.

[0095] (3) Class 2 acoustic environmental function zone: Refers to areas mainly with functions of commercial finance and market trade, or areas where residence, commerce, and industry are mixed, and which need to maintain the quietness of residences.

[0096] (4) Class 3 acoustic environmental function zone: Refers to areas mainly with functions of industrial production and warehousing and logistics, which need to prevent industrial noise from having a serious impact on the surrounding environment.

[0097] (5) Class 4 acoustic environmental function zone: Refers to areas within a certain distance on both sides of traffic arteries, which need to prevent traffic noise from having a serious impact on the surrounding environment. It includes two types: 4a and 4b. Type 4a is the area on both sides of expressways, first-class highways, second-class highways, urban expressways, urban arterial roads, urban sub-arterial roads, urban rail transit (ground section), and inland waterways; Type 4b is the area on both sides of railway main lines.

[0098] The "Acoustic Environment Quality Standard" (GB3096-2008) gives the corresponding equivalent continuous A-weighted sound pressure level limit values for various acoustic environmental function zones as shown in the following table. Take the equivalent continuous A-weighted sound pressure level limit values of the acoustic environmental function zones to which various buildings in the research area belong as the environmental noise limit values of their surfaces. For example, schools belong to Class 1 acoustic environmental function zones, and the environmental noise limit values of their building surfaces are taken as 55 dB(A) during the day and 45 dB(A) at night.

[0099] Table 1 Environmental Noise Limit Values

[0100]

[0101] S2. Based on the outdoor noise propagation attenuation mechanism, construct the spatial distribution model of the noise limit contour surface for a single building as shown in Figure 2 , and the specific steps are as follows;

[0102] S201. Based on the scope of the research area, select a coordinate origin on the geoid, use the due north direction as the Y-axis, the due east direction as the X-axis, and the upward direction perpendicular to the geoid as the Z-axis to establish a coordinate system.

[0103] S202. Perform grid processing on the outer surface of building j to obtain the three-dimensional spatial coordinates p i (x, y, z) (i = 1, 2, 3…);

[0104] S203. Based on the outdoor noise propagation attenuation mechanism, construct the noise limit at a point q i (x, y, z) with a vertical distance of r from a certain grid point p on the outer surface of the building i (x, y, z), and the calculation formula is as follows: Specifically as follows:

[0105]

[0106] In the formula: is the noise limit on the surface of building j; x div is the attenuation caused by geometric divergence; A atm is the attenuation caused by atmospheric absorption; A gr is the attenuation caused by ground effect; A misc is the attenuation caused by other various effects;

[0107] A div = 20lg(r0 / (r0 - r)) (26)

[0108] In the formula: r div is the attenuation caused by geometric divergence, dB; r0 is the distance from the point (x, y, z) on the building surface to the sound source, m.

[0109]

[0110] In the formula: A atm is the attenuation caused by atmospheric absorption, dB; α is the atmospheric absorption attenuation coefficient related to temperature, humidity, and sound wave frequency.

[0111]

[0112] In the formula: A gr is the attenuation caused by ground effect, dB; h m is the average height above the ground of the propagation path, m; r0 is the distance from the point (x, y, z) on the building surface to the sound source, m.

[0113] Attenuation A caused by other multi-faceted effects misc mainly includes the attenuation A caused by greening forest belts fol and the noise attenuation A of building complexes hous . Among them, A fol needs to be considered according to factors such as the vegetation type and the length of the forest belt in the actual environment; A hous The specific calculation formula is as follows:

[0114] A hous = 0.1Bd0 - 10lg(1 - p) (29)

[0115] In the formula: B is the density of buildings along the sound propagation route; d0 is the length of the sound propagation route through the building complex, m; p is the total length of the fronts of the buildings longitudinally distributed along the sound source divided by the corresponding length of the sound source.

[0116] S204. For the spatial points q limit (i = 1, 2, 3 …) with the same noise limit L i (r), perform three-dimensional surface fitting to obtain the noise limit surface corresponding to building j under this noise limit The noise limit surfaces together constitute the spatial distribution model of the noise limit contour surface of a single building j.

[0117] S3. Based on the spatial distribution model of the noise limit contour surface of various buildings in the urban area calculated in step S2, take the union of the intersecting contour surfaces with the same noise limit of each building to construct the overall building noise limit contour surface Ω of the urban area. The specific steps are as follows;

[0118] S301. Based on the spatial distribution model of the noise limit contour surface of a single building, calculate the noise limit contour surface Ω j corresponding to building j (j = 1, 2, …, n) in the urban area respectively.

[0119] S302. Among the noise limit contour surfaces of each building, the noise limit surfaces corresponding to the same noise limit together form the overall building noise limit surface of the urban area under this noise limit If there is an intersection between the noise limit surfaces of each building under the same noise limit, take the union as the overall building noise limit surface. For example, the overall building noise limit surface corresponding to the noise limit of L limit = kdB is Ω k ;

[0120] S303. The noise limit surfaces together constitute the overall building noise limit contour surface Ω of the urban area.

[0121] S4. Determine the candidate points P of the vertical takeoff and landing field according to the spatial distribution of the building noise limit contour surface Ω and the land use type distribution of the overall urban area m (m = 1, 2, 3…), and the specific steps are as follows;

[0122] S401. Denote the ground plane of the research area as a horizontal plane β, and the intersection of the plane β and the building noise limit contour surface Ω obtains the distribution of the building noise limit horizontal plane contour lines of the overall urban area;

[0123] S402. Given that the maximum noise generated by existing civil airliners is within 150 dB, and the noise generated by EVTOL aircraft is significantly lower than that of civil airliners, the 150 dB contour line is used as the basis for determining the boundary of the candidate area of the EVTOL vertical takeoff and landing field. Select the area outside the 150 dB contour line in the distribution of the building noise limit horizontal plane contour lines as the candidate area of the EVTOL vertical takeoff and landing field;

[0124] S403. Determine the candidate points P of the vertical takeoff and landing field in combination with the distribution of different land use types in the candidate area m (m = 1, 2, 3…);

[0125] S5. By comparing the noise value L when the noise of the EVTOL aircraft in the waiting-to-fly state propagates to a certain noise limit surface Ω at the candidate point k with the corresponding noise limit of the noise limit surface Ω evtol to determine whether the candidate point meets the noise requirements on the ground plane, see k the corresponding noise limit for the size relationship, and the specific steps are as follows; Figure 3

[0126] S501. Based on the operating characteristics of the EVTOL aircraft in the waiting-to-fly state, determine that the noise value of the aircraft in the waiting-to-fly state is

[0127]

[0127] S502. Select a certain candidate point P m , and calculate the noise of the aircraft m at P propagating to a certain noise limit surface Ω m to obtain the noise value L evtol , and judge the size relationship between the aircraft noise value L evtol and the corresponding noise limit of the noise limit surface Ω m ; between;

[0128] Among them, the noise of the aircraft propagating to a certain noise limit surface Ω k to obtain the noise value L evtol The calculation formula is as follows:

[0129]

[0130] Where: A div is the attenuation caused by geometric divergence; A atm is the attenuation caused by atmospheric absorption; A gr is the attenuation caused by ground effect; A misc is the attenuation caused by other multi-faceted effects.

[0131] The calculation formulas for each noise propagation attenuation term are as follows:

[0132]

[0133] Where: A div is the attenuation caused by geometric divergence, dB; d is the distance between the aircraft and the noise limit surface.

[0134]

[0135] Where: A atm is the attenuation caused by atmospheric absorption, dB; α is the atmospheric absorption attenuation coefficient related to temperature, humidity and sound wave frequency; d is the distance between the aircraft and the noise limit surface.

[0136]

[0137] Where: A gr is the attenuation caused by ground effect, dB; h m is the average height above the ground of the propagation path; d is the distance between the aircraft and the noise limit surface.

[0138] The attenuation A caused by other multi-faceted effects misc mainly includes the attenuation A fol caused by the greening forest belt and the noise attenuation A hous of the building complex. Among them, A fol needs to be considered according to factors such as the vegetation type and the length of the forest belt in the actual environment; A hous The calculation formula is specifically as follows:

[0139] A hous = 0.1Bd0 - 10lg(1 - p) (34)

[0140] Where: B is the density of the buildings along the sound propagation route; d0 is the length of the sound propagation route through the building complex; p is the total length of the fronts of the buildings longitudinally distributed along the sound source divided by the corresponding length of the sound source.

[0141] S503. If indicates the candidate point P mIt fails to meet the building noise limit requirements during the waiting - for - flight state of the EVTOL aircraft, so this candidate point is excluded. Select a new candidate point and go back to step S5 to verify in turn whether the aircraft meets the building noise limit requirements when operating at the candidate point; if Indicates that candidate point P m Meets the building noise limit requirements during the waiting - for - flight state of the EVTOL aircraft, and it is necessary to further execute step S6 to verify whether it meets the building noise limit requirements during the aircraft operation process;

[0142] S6. Considering comprehensively the parameters such as the hover height, the approach / take - off climb surface slope, and different approach / take - off climb surface angles during the vertical take - off and landing phase and the approach / take - off climb phase of the EVTOL aircraft, determine its operation trajectory ξ, as shown in Figure 4 , and the specific steps are as follows;

[0143] S601. According to the differences in the operation characteristics of the EVTOL aircraft during the vertical take - off and landing phase and the approach / take - off climb phase, determine the hover height at the transition between the two phases, denoted as h0; determine the approach / take - off climb angle, denoted as α, then the approach / take - off climb surface slope can be expressed as tan(α).

[0144] S602. The operation trajectory ξ of the EVTOL aircraft is composed of the vertical take - off and landing center line in the vertical take - off and landing phase and the approach / take - off climb surface center line in the approach / take - off climb phase. Let the coordinates of the EVTOL aircraft during operation be (x evtol , y evtol , z evtol ), and the coordinates of the candidate point P m of the vertical take - off and landing field are (x Pm , y Pm , 0), then its operation trajectory ξ can be specifically expressed as:

[0145] Vertical take - off and landing process:

[0146]

[0147] In the formula, h0 is the hover height at the transition between the two phases of the EVTOL aircraft operation.

[0148] Approach / take - off climb phase:

[0149]

[0150] In the formula, ΔD is a certain length of the EVTOL aircraft flying along the midline of the approach / takeoff climb surface; α is the approach / takeoff climb angle of the aircraft; β is the angle between the projection of the midline of the approach / takeoff climb surface on the ground plane and the x-axis. If there are two or more approach / takeoff climb surfaces set at the vertical takeoff and landing site, the trajectory of the EVTOL aircraft running along a certain approach / takeoff climb surface can be calculated by formula (7).

[0151] S7. By comparing the noise value L k when the noise of the EVTOL aircraft propagates to a certain noise limit surface Ω evtol during the operation along the trajectory ξ, with the corresponding noise limit k of this noise limit surface Ω to check whether the candidate point satisfies the noise requirements during the spatial operation process, and finally determine the location of the vertical takeoff and landing site, as shown in Figure 5 . The specific steps are as follows.

[0152] S701. Based on the noise characteristics of the EVTOL aircraft in flight state, determine that the noise value of the aircraft in flight state is The noise values of some existing EVTOL aircraft during operation are shown in the following table:

[0153] Table 2 Maximum A-weighted sound pressure level during the horizontal flight of the aircraft

[0154] Aircraft <![CDATA[Air speed / (m·s -1 )]]> Maximum A-weighted sound pressure level / dBA Joby S4 49 45 Joby S4 51 46 Cirrus SR22 51 59 Beechcraft Baron 55 51 63 Leonardo AW109 51 61 Bell 209 51 58 Robinson R44 51 57

[0155] S702. Calculate the noise value L k when the noise of the aircraft propagates to a certain noise limit surface Ω evtol during the operation along the trajectory ξ, and judge the magnitude relationship between the aircraft noise value L evtol and the corresponding noise limit k of the noise limit surface Ω ;

[0156] S703. If it indicates that this candidate point P m does not meet the building noise limit requirements during the flight of the EVTOL aircraft, and this candidate point is excluded. Select a new candidate point and go back to step S5 to verify whether the aircraft meets the building noise limit requirements when operating at the candidate point in turn; if it indicates that this candidate point P m meets the building noise limit requirements during the waiting flight state and flight process of the EVTOL aircraft, and it can be used as the location point of the urban area vertical takeoff and landing site based on the building noise limit conditions. Select a new candidate point and go back to step S5 to verify whether the aircraft meets the building noise limit requirements when operating at the candidate point in turn;

[0157] Finally, after the noise limit test of EVTOL aircraft at all candidate vertical takeoff and landing sites, the location range of the vertical takeoff and landing site is determined. The relationship between the candidate sites of the vertical takeoff and landing site and the final selected area is shown in Figure 6 .

[0158] Preferably, the embodiments of the present application also provide a specific implementation manner of an electronic device that can implement all steps in the above-mentioned EVTOL vertical takeoff and landing site selection decision method based on the noise propagation mechanism. The electronic device specifically includes the following:

[0159] A processor, a memory, a communication interface, and a bus;

[0160] Among them, the processor, the memory, and the communication interface communicate with each other through the bus; the communication interface is used to implement information transmission between related devices such as server-side devices, metering devices, and user-side devices.

[0161] The processor is used to call the computer program in the memory. When the processor executes the computer program, it implements all steps in the above-mentioned EVTOL vertical takeoff and landing site selection decision method based on the noise propagation mechanism.

[0162] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments. In particular, for the hardware + program type embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0163] The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain implementations, multitasking and parallel processing are also possible or may be advantageous.

[0164] Although the present application provides method operation steps such as in the embodiments or flowcharts, based on routine or non-creative labor, there can be more or fewer operation steps. The order of steps listed in the embodiments is only one way among many execution orders of steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order shown in the embodiments or the figures or in parallel (for example, in an environment of parallel processors or multithreaded processing).

[0165] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0166] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device, and the instruction device implements the functions specified in one Figure 1 process or multiple processes and / or Figure 1 boxes or multiple boxes.

[0167] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one Figure 1 process or multiple processes and / or Figure 1 boxes or multiple boxes.

[0168] The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be executed in a different order than in the embodiments and still achieve the desired result.

[0169] Although this application provides method operation steps such as in the embodiments or flowcharts, based on routine or non-creative labor, there can be more or fewer operation steps. The order of steps listed in the embodiments is only one way among many execution orders of steps and does not represent the only execution order.

[0170] The present invention is not limited to the above-described embodiments. The above description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the spirit of the present invention and the scope protected by the claims, those of ordinary skill in the art can make many specific transformations in various forms under the inspiration of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for site selection of EVTOL vertical take-off and landing site based on noise propagation mechanism, characterized in that: The following steps are involved: S1. Based on the acoustic environment functional zoning corresponding to different land use types, determine the environmental noise limit of the building surface corresponding to each building in the urban area S2. Based on the outdoor noise propagation attenuation mechanism, a single building noise limit contour spatial distribution model is constructed; S3. Calculate and obtain the spatial distribution model of the noise limit contour surface of various types of buildings in the urban area, take the union of the intersecting contour surfaces with the same noise limit of each building, and construct the overall building noise limit contour surface Ω of the urban area; S4. Determine the candidate location P of the vertical take-off and landing site based on the spatial distribution of the building noise limit contour surface Ω and the land use type distribution in the urban area as a whole. m , m=1,2,3…,; S5. By comparing the noise propagation of the EVTOL aircraft in the ready-to-fly state at the candidate point to a certain noise limit surface Ω m The noise value L evtol The noise limit value is Ω m Corresponding noise limit The size relationship is used to determine whether the candidate point meets the noise requirements on the ground plane; S6. Comprehensively consider the hovering altitude, approach / take-off climb surface slope, and different approach / take-off climb surface angle parameter requirements of the EVTOL aircraft during the vertical take-off and landing phase and the approach / take-off climb phase, and determine its operation trajectory ξ; S7. By comparing the noise propagation of the EVTOL aircraft along the operating trajectory ξ to a certain noise limit surface Ω k The noise value L evtol The noise limit value is Ω k Corresponding noise limit The size relationship is determined to verify whether the candidate points meet the noise requirements of the space operation process, and finally determine the site selection of the vertical take-off and landing field.

2. According to claim 1, a method for decision-making on site selection of EVTOL vertical take-off and landing site based on noise propagation mechanism, characterized in that: Step S1 includes the following steps: S101. Determine the corresponding acoustic environment functional zone based on the land use type of building j, obtain the corresponding noise equivalent sound level limit value based on it, and use this as the environmental noise limit value on the surface of building j Where n is the number of buildings in the urban area.

3. According to the method for site selection of EVTOL vertical take-off and landing site based on noise propagation mechanism of claim 1, it is characterized by: Step S2 includes the following steps: S201. Based on the scope of the urban area under study, a coordinate origin is selected on the geoid, and a coordinate system is established with due north as the Y axis, due east as the X axis, and the upward direction perpendicular to the geoid as the Z axis; S202. Grid the outer surface of building j to obtain the three-dimensional spatial coordinates p of each grid point i (x, y, z), i = 1, 2, 3, ...; S203. Based on the outdoor noise propagation attenuation mechanism, a grid point p on the outer surface of the building is constructed. i (x,y,z) is a point q at a vertical distance r i Noise limit for (x,y,z) The calculation formula of S204. For the same noise limit L limit (r) space point q i Perform three-dimensional surface fitting, i = 1, 2, 3..., to obtain the noise limit surface corresponding to building j under this noise limit. Each noise limit surface together constitutes the noise limit contour surface spatial distribution model of single building j.

4. According to claim 3, a method for decision-making on site selection of EVTOL vertical take-off and landing site based on noise propagation mechanism, characterized in that: The calculation formula based on the outdoor noise propagation attenuation mechanism in step S203 is as follows: Where: A is the environmental noise limit on the surface of building j; div is the attenuation caused by geometric divergence; A atm A is the attenuation caused by atmospheric absorption; gr A is the attenuation caused by ground effect; misc Attenuation caused by other multi-faceted effects; The calculation formulas for each noise propagation attenuation term are as follows: A div =20lg(r0 / (r0-r)) (2) Where: A div is the attenuation caused by geometric divergence, dB; r0 is the distance from the building surface point (x, y, z) to the sound source, m; r is the vertical distance, m; Where: A atm is the attenuation caused by atmospheric absorption, dB; α is the atmospheric absorption attenuation coefficient related to temperature, humidity and sound wave frequency; Where: A gr is the attenuation caused by ground effect, dB; h m is the average height of the propagation path from the ground, m; r0 is the distance from the building surface point (x, y, z) to the sound source, m; Attenuation caused by other multi-effects A misc Including the attenuation caused by green belts A fol and building noise attenuation A hous ; Among them, A fol Consider factors such as vegetation type and forest belt length in the actual environment; A hous The calculation formula is as follows: A hous =0.1Bd0-10lg(1-p) (5) Where: B is the density of buildings along the sound propagation route; d0 is the length of the sound propagation route through the building complex, m; p is the total length of the building frontage along the longitudinal distribution of the sound source divided by the corresponding sound source length.

5. According to the method for site selection of EVTOL vertical take-off and landing site based on noise propagation mechanism of claim 1, it is characterized by: Step S3 includes the following steps: S301. Based on the single building noise limit contour surface spatial distribution model, calculate the noise limit contour surface Ω corresponding to building j in the urban area j , j = 1, 2, ..., n; S302. In each building noise limit contour surface, the noise limit surfaces corresponding to the same noise limit value together constitute the overall building noise limit surface of the urban area under this noise limit value. If the noise limit surfaces of the same noise limit of each building intersect, the union is taken as the overall building noise limit surface; S303. Noise limit surfaces Together they constitute the building noise limit contour surface Ω for the entire urban area.

6. The method for site selection of an EVTOL vertical take-off and landing site based on noise propagation mechanism according to claim 1, characterized in that: Step S4 includes the following steps: S401. The ground plane of the study area is recorded as a horizontal plane β, and the plane β intersects with the building noise limit contour plane Ω to obtain the distribution of the building noise limit horizontal plane contour lines of the entire urban area; S402. Select an area outside a certain noise limit contour line in the horizontal plane contour line distribution of the building noise limit as a candidate area for the EVTOL vertical take-off and landing site; S403. Determine the candidate point P of the vertical take-off and landing site based on the distribution of different land use types in the candidate area m , m=1,2,3…。 7. The method for site selection of an EVTOL vertical take-off and landing site based on noise propagation mechanism according to claim 1, characterized in that: Step S5 includes the following steps: S501. Based on the operational characteristics of the EVTOL aircraft in the standby state, determine the noise value of the aircraft in the standby state. S502. Select a candidate point P m , in P m Calculate aircraft noise Propagate to a certain noise limit surface Ω m The noise value L evtol , and determine the aircraft noise value L evtol And the noise limit surface Ω m Corresponding noise limit The size relationship between them; Among them, aircraft noise Propagate to a certain noise limit surface Ω m The noise value L evtol The calculation formula is as follows: Where: A div is the attenuation caused by geometric divergence; A atm A is the attenuation caused by atmospheric absorption; gr A is the attenuation caused by ground effect; misc The attenuation is caused by other multi-effects; the attenuation term calculation formula is the same as step S204; The calculation formulas for each noise propagation attenuation term are as follows: Where: A div is the attenuation caused by geometric divergence, dB; d is the distance between the aircraft and the noise limit surface; Where: A atm is the attenuation caused by atmospheric absorption, dB; α is the atmospheric absorption attenuation coefficient related to temperature, humidity and sound wave frequency; d is the distance between the aircraft and the noise limit surface; Where: A gr is the attenuation caused by ground effect, dB; h m is the average ground height of the propagation path; d is the distance between the aircraft and the noise limit surface; Attenuation caused by other multi-effects A misc Including the attenuation caused by green belts A fol and building noise attenuation A hous Among them, A fol It needs to be considered based on the vegetation type and forest belt length in the actual environment; A hous The calculation formula is as follows: A hous =0.1Bd0-10lg(1-p) (10) Where: B is the density of buildings along the sound propagation route; d0 is the length of the sound propagation route through the building complex; p is the total length of the building frontage along the longitudinal distribution of the sound source divided by the corresponding sound source length; S503. If Indicates the candidate point P m If the building noise limit requirements for the EVTOL aircraft in the standby state cannot be met, this candidate point is excluded; a new candidate point is selected and the process returns to step S5 to verify whether the aircraft meets the building noise limit requirements when operating at the candidate point; if Indicates the candidate point P m If the building noise limit requirements for the EVTOL aircraft in the standby state are met, step S6 is further performed to verify whether the building noise limit requirements during the aircraft operation are met.

8. The method for site selection of an EVTOL vertical take-off and landing site based on noise propagation mechanism according to claim 1, characterized in that: Step S6 includes the following steps: S601. According to the difference in the operating characteristics of the EVTOL aircraft during the vertical take-off and landing phase and the approach / take-off climb phase, determine the hovering height at the transition between the two phases, denoted as h0; determine the approach / take-off climb angle, denoted as α, and the approach / take-off climb surface slope is expressed as tan(α); S602. The EVTOL aircraft operation trajectory ξ is composed of the vertical take-off and landing centerline of the vertical take-off and landing phase and the approach / take-off climb surface centerline of the approach / take-off climb phase; let the coordinates of the EVTOL aircraft during operation be (x evtol ,y evtol ,z evtol ), candidate point P of vertical take-off and landing field m The coordinates are Then its running trajectory ξ is specifically expressed as: Vertical take-off and landing process: Where h0 is the hovering height at the transition between the two stages of the EVTOL aircraft operation process; Approach / Takeoff Climb Phase: Wherein, ΔD is the length of a certain section of the EVTOL aircraft flying along the centerline of the approach / take-off climb surface; α is the aircraft approach / take-off climb angle; β is the angle between the projection of the centerline of the approach / take-off climb surface on the ground plane and the x-axis; if the vertical take-off and landing field is equipped with two or more approach / take-off climb surfaces, the trajectory of the EVTOL aircraft running along a certain approach / take-off climb surface can be calculated by formula (7).

9. The method for site selection of an EVTOL vertical take-off and landing site based on noise propagation mechanism according to claim 1, characterized in that: Step S7 includes the following steps: S701. Based on the noise characteristics of the EVTOL aircraft flight state, determine the aircraft flight state noise value S702. Calculate the noise propagation of the aircraft along the trajectory ξ to a certain noise limit surface Ω k The noise value L evtol , and determine the aircraft noise value L evtol And the noise limit surface Ω k Corresponding noise limit The size relationship between them; S703. If Indicates that this candidate point P m If the building noise limit requirements during the flight of the EVTOL aircraft cannot be met, this candidate point is excluded; a new candidate point is selected and the process returns to step S5 to verify whether the aircraft meets the building noise limit requirements when operating at the candidate point; if Indicates the secondary candidate point P m Meeting the building noise limit requirements for EVTOL aircraft in the standby state and during flight can be used as a site selection point for urban vertical take-off and landing fields based on building noise limit conditions; selecting a new candidate point and returning to step S5 to verify in turn whether the aircraft meets the building noise limit requirements when operating at the candidate point.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the EVTOL vertical take-off and landing site selection decision method based on the noise propagation mechanism as described in any one of claims 1 to 9 are implemented.

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