Airspace resource optimization allocation method and system for urban low-altitude flight

Abstract

The present application relates to the field of aircraft flight control technology, in particular to an airspace resource optimization allocation method and system for urban low-altitude flight. The method comprises: obtaining wind resistance coefficients and voltage drop correction ratios based on actual flight data of sampling aircraft in each grid unit and aircraft aerodynamic parameters in a historical period, and then constructing a historical database; obtaining a predicted load voltage according to the working condition data of the grid unit passed by the planned route of the planning aircraft and the similar working condition data in the corresponding historical database, and then determining the voltage limited maximum speed; calculating the whole passage delay time length of the planning aircraft according to the voltage limited maximum speed; adjusting the actual take-off time slot of the planning aircraft by using the whole passage delay time length, and issuing the voltage limited maximum speed as a speed limit instruction to the planning aircraft. The present application realizes the individualized safety control of different aircraft and the dynamic optimization and safety allocation of airspace resources, and improves the passage efficiency of the airspace.

Description

Technical Field

[0001] This invention relates to the field of aircraft flight control technology, specifically to a method and system for optimizing the allocation of airspace resources for low-altitude urban flight. Background Technology

[0002] With the development of urban air traffic, electric vertical takeoff and landing (EVTOL) aircraft are increasingly routinely flying along routes through densely built-up urban areas. Unlike open airspace, urban canyon environments have complex and uneven airflow fields, with strong turbulence or gusts frequently occurring in localized areas. In actual operation, to maintain attitude stability and track consistency in turbulent conditions, the aircraft's motor system requires high-frequency power adjustments, resulting in severe pulse-like fluctuations in battery output power. For existing electric aircraft, the terminal voltage of their power batteries is not only affected by average load but is also extremely sensitive to such high-frequency pulse loads. Especially when the battery is aging (increased internal resistance) or low in charge, severe power fluctuations can easily cause the battery terminal voltage to drop instantaneously to the low-voltage protection threshold of the flight control system.

[0003] Existing airspace resource allocation or flow control methods typically rely solely on static scheduling based on the aircraft's nominal cruise speed or simple range estimation based on remaining battery power. These methods ignore the nonlinear coupling between the turbulence characteristics of a specific geographical environment and the aircraft's battery health. In actual flight, if this voltage drop risk is not anticipated, the aircraft may be forced to decelerate or even hover due to triggering low-voltage protection when flying over turbulent areas. This unintended in-flight deceleration can instantly disrupt the previously tight queue spacing, leading to a chain reaction of congestion or avoidance risks for subsequent aircraft, severely reducing airspace efficiency and safety. Summary of the Invention

[0004] To address the issue that existing airspace resource allocation methods for urban low-altitude flights fail to consider the dynamic impact of complex urban low-altitude airflow environments on the battery voltage of electric aircraft, leading to flight safety problems due to unexpected voltage drops, this invention aims to provide an optimized airspace resource allocation method and system for urban low-altitude flights. The specific technical solution adopted is as follows:

[0005] In a first aspect, the present invention provides a method for optimizing the allocation of airspace resources for low-altitude urban flight, the method comprising the following steps:

[0006] Acquire actual flight data, electrical bus data, and aerodynamic parameters of the sampling aircraft during the level flight cruise phase;

[0007] Based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during historical periods, the drag coefficient and voltage sag correction ratio of the sampled aircraft when passing through each grid cell are obtained; and a historical database of each grid cell is constructed using the drag coefficient, voltage sag correction ratio and electrical bus data during historical periods.

[0008] Based on the operating condition data of the grid cells traversed by the planned flight path of the planned aircraft and the similar operating condition data in the corresponding historical database, the predicted load voltage of the planned aircraft in the corresponding grid cell is obtained; based on the predicted load voltage, the voltage-limited maximum speed corresponding to the grid cell is determined.

[0009] The total travel delay time of the planned aircraft is calculated based on the voltage-limited maximum speed; the actual takeoff time slot of the planned aircraft is adjusted using the total travel delay time, and the voltage-limited maximum speed is issued to the planned aircraft as a speed limit command.

[0010] Preferably, the acquisition of the drag coefficient and voltage drop correction ratio of the sampling aircraft as it passes through each grid cell includes:

[0011] The electrical bus data includes battery open-circuit voltage, battery internal resistance, measured bus voltage, and measured bus current.

[0012] Based on the actual flight data of the sampling aircraft during its flight in the candidate unit, the power component of the sampling aircraft's work against gravity is determined; based on the law of conservation of energy, the actual mechanical thrust is determined using the power component and the mass of the sampling aircraft; based on the aerodynamic parameters of the sampling aircraft and the actual flight data, the theoretical reference thrust is obtained.

[0013] The ratio of the actual mechanical thrust to the theoretical reference thrust is determined as the drag coefficient of the sampling aircraft when it passes through the candidate unit;

[0014] Based on Ohm's law, and using the battery's internal resistance and the measured bus current, the linear resistive voltage drop is obtained.

[0015] By combining the linear resistive voltage drop and the total voltage drop from the battery open-circuit voltage to the measured bus voltage, the voltage drop correction ratio when the sampling aircraft passes through the candidate unit is obtained;

[0016] The candidate cell can be any grid cell.

[0017] Preferably, the step of constructing a historical database for each grid cell using drag coefficients, voltage sag correction ratios, and electrical bus data over historical periods includes:

[0018] By utilizing the drag coefficient, measured bus current, battery internal resistance, and voltage drop correction ratio of each sampled aircraft when passing through the candidate unit during historical periods, historical feature records of the candidate unit are generated; all the historical feature records of the candidate unit constitute the historical database of the candidate unit.

[0019] Preferably, the step of obtaining the predicted load voltage of the planned aircraft in the corresponding grid cell based on the operating condition data of the grid cells traversed by the planned flight path of the planned aircraft and similar operating condition data in the corresponding historical database includes:

[0020] For candidate units:

[0021] Based on the effective mechanical power of the battery corresponding to the planned aircraft and the propulsion power required to overcome air resistance, a power balance equation is constructed; the reference theoretical load current is solved using the power balance equation; the effective mechanical power is determined based on the overall efficiency of the power system, the battery open-circuit voltage, the battery internal resistance, and the reference theoretical load current; the propulsion power required to overcome air resistance is determined based on the drag coefficient, standard atmospheric density, air resistance coefficient, effective frontal reference area, and preset cruise speed of the planned aircraft when passing through the candidate unit;

[0022] Calculate the linear resistive voltage drop of the planned aircraft under the baseline theoretical load current;

[0023] A query feature vector is constructed using the current drag coefficient of the candidate unit, the baseline theoretical load current of the planned aircraft, and its battery internal resistance; the current drag coefficient of the candidate unit is the average of all drag coefficients of the aircraft when it passes the candidate unit in the historical database;

[0024] In the historical database of the candidate unit, the statistical distance between the query feature vector and the corresponding feature vector in each historical feature record is calculated; a preset number of historical feature records with the smallest statistical distance are selected as similar working condition samples.

[0025] The voltage drop correction ratio of the similar operating condition samples is weighted using the statistical distance to obtain the predicted voltage correction ratio of the planned aircraft in the candidate unit.

[0026] The linear resistive voltage drop is corrected using the predicted voltage correction ratio. The corrected linear resistive voltage drop is then combined with the open-circuit voltage of the planned aircraft's battery to obtain the predicted load voltage of the planned aircraft in the candidate unit.

[0027] Preferably, the step of correcting the linear resistive voltage drop using the predicted voltage correction ratio, and combining the corrected linear resistive voltage drop with the open-circuit voltage of the planned aircraft's battery to obtain the predicted load voltage of the planned aircraft in the candidate cell, includes:

[0028] The product of the predicted voltage correction ratio and the linear resistive voltage drop is taken as the corrected linear resistive voltage drop.

[0029] The difference between the battery open-circuit voltage of the planned aircraft and the corrected linear resistive voltage drop is used as the predicted load voltage of the planned aircraft in the candidate cell.

[0030] Preferably, determining the voltage-constrained maximum speed corresponding to the grid cell based on the predicted load voltage includes:

[0031] Calculate the sum of the low-voltage protection threshold and the preset safety voltage margin;

[0032] If the predicted load voltage is greater than the sum of the values, then the preset cruising speed will be used as the maximum speed limited by the voltage.

[0033] If the predicted load voltage is less than or equal to the sum of the values, the maximum safe current is calculated based on the predicted voltage correction ratio, the battery internal resistance, and the maximum allowable safe voltage drop; the voltage-limited maximum speed is solved by the power balance equation based on the maximum safe current and the current drag coefficient of the candidate cell.

[0034] Preferably, the step of calculating the total travel delay time of the planned aircraft based on the voltage-limited maximum speed includes:

[0035] For each grid cell on the planned route, the local delay time caused by speed limitation in each grid cell is calculated based on the geometric path length, preset cruise speed, and the voltage-limited maximum speed of each grid cell.

[0036] The total travel delay time is obtained by summing the local delay times of all grid cells on the planned route.

[0037] Preferably, before adjusting the actual takeoff time slot of the planned aircraft, a circuit breaker determination step is also included:

[0038] If the total travel delay exceeds the preset maximum allowable delay threshold, or if the voltage limit of any grid cell is zero, then the current flight plan of the aircraft will be rejected.

[0039] Preferably, adjusting the actual takeoff time slot of the planned aircraft using the total travel delay time includes:

[0040] The total adjustment time is obtained by adding the total delay time to the preset buffer time;

[0041] The original planned base departure time slot of the planned aircraft is postponed by the total adjustment time to obtain the adjusted actual takeoff time slot.

[0042] Secondly, the present invention provides an airspace resource optimization and allocation system for urban low-altitude flight, the system being used to implement the method of the first aspect, the system comprising:

[0043] The data acquisition module is used to acquire actual flight data, electrical bus data, and aerodynamic parameters of the sampling aircraft during the level flight cruise phase of flight.

[0044] The historical database construction module is used to obtain the drag coefficient and voltage sag correction ratio of the sampled aircraft when passing through each grid cell based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during the historical period; and to construct the historical database of each grid cell using the drag coefficient, voltage sag correction ratio and electrical bus data during the historical period.

[0045] The maximum speed determination module is used to obtain the predicted load voltage of the planned aircraft in the corresponding grid cell based on the operating condition data of the grid cell through which the planned flight path passes and the similar operating condition data in the corresponding historical database; and to determine the voltage-limited maximum speed corresponding to the grid cell based on the predicted load voltage.

[0046] The adjustment module is used to calculate the total travel delay time of the planned aircraft based on the voltage-limited maximum speed; adjust the actual takeoff time slot of the planned aircraft using the total travel delay time; and issue the voltage-limited maximum speed as a speed limit command to the planned aircraft.

[0047] The present invention has at least the following beneficial effects:

[0048] This invention, by collecting actual flight data, electrical bus data, and aerodynamic parameters of a sampled aircraft during the level flight cruise phase, can extract the drag coefficient and voltage drop correction ratio reflecting the influence of airflow in specific grid cells. This enables the quantification of the complex aerodynamic environment and battery electrical response characteristics in urban low-altitude areas, providing a reliable environmental and electrical coupling data foundation for subsequent predictions. Based on the drag coefficient, voltage drop correction ratio, and electrical data in the historical database, combined with the operating conditions of the grid cells traversed by the currently planned aircraft route, the load voltage in each grid cell can be predicted. This predicted value is then used to further determine the maximum voltage-limited speed in each grid cell, enabling early identification and quantitative assessment of the risk of battery voltage drop caused by environmental turbulence during flight. This improves the voltage safety prediction capability of the aircraft flying in complex airflow environments. Based on the maximum voltage-limited speed, the total travel delay time caused by speed limitation of the planned aircraft is derived, and its actual takeoff time slot is adjusted accordingly. At the same time, a speed limit command is issued to the aircraft. This method can adapt to the dynamic changes in the urban low-altitude environment, realize personalized safety management and control of different aircraft, and dynamically optimize and safely allocate airspace resources, avoid safety problems caused by abnormal deceleration in the air due to voltage drops, and improve the efficiency of airspace passage. Attached Figure Description

[0049] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 A flowchart illustrating an airspace resource optimization allocation method for urban low-altitude flight provided in an embodiment of the present invention;

[0051] Figure 2 This is a structural block diagram of an airspace resource optimization and allocation system for urban low-altitude flight provided in an embodiment of the present invention. Detailed Implementation

[0052] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description of the airspace resource optimization allocation method and system for urban low-altitude flight proposed according to the present invention is provided in conjunction with the accompanying drawings and preferred embodiments.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0054] The following description, in conjunction with the accompanying drawings, details the specific scheme of the airspace resource optimization allocation method and system for urban low-altitude flight provided by this invention.

[0055] Example of an optimized allocation method for airspace resources for low-altitude urban flight:

[0056] The specific scenario addressed in this embodiment is as follows: In the process of optimizing the allocation of airspace resources for low-altitude urban aircraft, by collecting and analyzing data on the flight status of sampled aircraft during historical flight operations, the drag coefficient and voltage drop correction ratio are determined. The impact of environmental turbulence on the electrical system is characterized, and historical operating conditions similar to the current operating conditions are matched to correct the linear voltage prediction model. Ultimately, the implicit voltage drop risk is transformed into explicit takeoff delay time, thereby achieving safe allocation of airspace resources.

[0057] This embodiment proposes a method for optimizing the allocation of airspace resources for low-altitude urban flights, such as... Figure 1 As shown, a method for optimizing airspace resource allocation for low-altitude urban flight in this embodiment includes the following steps:

[0058] Step S1: Obtain the actual flight data, electrical bus data, and aerodynamic parameters of the sampling aircraft during the level flight cruise phase.

[0059] First, a data acquisition mechanism is established using navigation grid cells in geospatial space as index references. Each navigation grid cell can be divided into a cubic space with fixed length, width, and height. In this embodiment, the dimensions of the cubic space are... In specific applications, implementers can set it according to the specific situation, and the navigation grid unit will be referred to as the grid unit thereafter.

[0060] During the historical period, multiple sampling aircraft conducted flights, collecting actual flight data, electrical bus data, and aerodynamic parameters of the aircraft as it passed through each grid cell during the level flight cruise phase.

[0061] The actual flight data includes the horizontal velocity relative to the ground and the pitch angle of the fuselage. For any grid cell, the average value of all the horizontal velocities of the fuselage relative to the ground collected when the aircraft passes through the grid cell is obtained as the horizontal velocity of the aircraft relative to the ground when passing through the grid cell. The average value of all the pitch angles of the fuselage collected when the aircraft passes through the grid cell is obtained as the pitch angle of the aircraft when passing through the grid cell, which is used to characterize the average motion state of the aircraft when passing through the grid cell.

[0062] The electrical bus data includes battery open-circuit voltage, battery internal resistance, measured bus voltage, and measured bus current. The battery open-circuit voltage is the battery electromotive force estimated by the battery management system based on the current state of charge. The battery internal resistance is a dynamic internal resistance value obtained from a table based on the current battery temperature and aging level. For any grid cell, the lowest voltage value among all voltage values ​​collected during the aircraft's passage through that grid cell is taken as the measured bus voltage when the aircraft passes through that grid cell. This voltage value reflects the maximum voltage drop pressure the battery withstands under the corresponding environment. The peak current among all current values ​​collected during the aircraft's passage through that grid cell is taken as the measured bus current when the aircraft passes through that grid cell. This current value reflects the instantaneous maximum torque current required to resist maximum gust interference. Aircraft aerodynamic parameters include the aircraft's effective frontal reference area, drag coefficient, and overall power system efficiency. The effective frontal reference area is the nominal frontal cross-sectional area of ​​the aircraft in level flight cruise attitude.

[0063] The historical time period is a preset time period before the current flight process of the planned aircraft. The implementer can set the preset time period according to the specific situation. In this embodiment, the historical time period is 30 minutes. In specific applications, the implementer can set it according to the specific situation.

[0064] The above method enables the collection of actual flight data, electrical bus data, and aerodynamic parameters of each sampled aircraft during the level flight cruise phase.

[0065] Step S2: Based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during the historical period, obtain the drag coefficient and voltage drop correction ratio of the sampled aircraft when passing through each grid cell; and construct a historical database for each grid cell using the drag coefficient, voltage drop correction ratio and electrical bus data during the historical period.

[0066] Because directly measured voltage and current data incorporates multiple factors such as work done by gravity, aerodynamic drag, and battery internal resistance, they cannot be directly used for cross-aircraft prediction. Next, we will utilize physical conservation laws and the definition of ratios to extract standardized features, namely the grid environmental pressure fingerprint. The grid environmental pressure fingerprint includes the drag coefficient and voltage drop correction ratio.

[0067] Step S21: Based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during the historical period, obtain the drag coefficient of the sampled aircraft when passing through each grid cell.

[0068] This embodiment uses a single grid cell as an example for illustration. Other grid cells can be processed using the method provided in this embodiment.

[0069] Specifically, any grid cell is designated as a candidate cell. Based on the actual flight data of the sampling aircraft flying through the candidate cells, the power component of the work done by the sampling aircraft against gravity is determined; the power component of the work done by the sampling aircraft against gravity can be expressed as:

[0070]

[0071] in, This represents the power component of the work done by the i-th sampling spacecraft against gravity. This represents the mass of the i-th sampling aircraft. Represents gravitational acceleration. This represents the horizontal velocity of the i-th sampling vehicle relative to the ground as it passes through the candidate cell. This represents the pitch angle of the i-th sampling vehicle as it passes through the candidate cell. It represents the sine value.

[0072] Based on the law of conservation of energy, using the power components obtained above and the mass of the sampled aircraft, the gravitational power and motor losses are subtracted from the total electrical power output by the battery to calculate the actual mechanical thrust used to overcome air resistance. Based on the aerodynamic parameters of the aircraft and actual flight data, the theoretical reference thrust under standard atmospheric density and windless conditions is calculated using aerodynamic formulas. The actual mechanical thrust and the theoretical reference thrust can be expressed as follows:

[0073]

[0074]

[0075] in, Indicates actual mechanical thrust. This represents the measured bus voltage of the i-th sampling aircraft as it passes through the candidate cell. This represents the measured bus current when the i-th sampling aircraft passes through the candidate cell. This represents the overall efficiency of the propulsion system of the i-th sampling aircraft. Indicates the theoretical reference thrust. Indicates standard atmospheric density. This represents the air resistance coefficient corresponding to the i-th sampling aircraft. It represents the effective frontal reference area of ​​the i-th sampling vehicle when passing through the candidate cell.

[0076] Furthermore, the ratio of actual mechanical thrust to theoretical reference thrust is used as the drag coefficient of the candidate unit. The drag coefficient is used to quantify the degree of additional obstruction to the aircraft by the ambient airflow within the grid unit. A drag coefficient greater than 1 indicates that the grid unit has headwind or turbulent obstruction, and the larger the value, the stronger the drag. A drag coefficient less than 1 indicates that there is tailwind boost.

[0077] Step S22: Based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during the historical period, obtain the voltage drop correction ratio when the sampled aircraft passes through each grid cell.

[0078] This step evaluates the deviation of the actual voltage drop from the ideal linear resistive voltage drop and obtains the voltage drop correction ratio.

[0079] First, based on Ohm's law, the linear resistive voltage drop is obtained from the battery's internal resistance and the measured bus current. Specifically, the product of the battery's internal resistance and the measured bus current when the sampling aircraft passes through the candidate cell is taken as the linear resistive voltage drop when the sampling aircraft passes through the candidate cell. The difference between the battery's open-circuit voltage and the measured bus voltage is taken as the total voltage drop between the battery's open-circuit voltage and the measured bus voltage.

[0080] After obtaining the total voltage drop between the battery open-circuit voltage and the measured bus voltage, it can be determined whether the total voltage drop is less than a preset voltage drop threshold. If the total voltage drop is less than the preset voltage drop threshold, the voltage drop correction ratio of the candidate unit is set to a preset reference value. In this embodiment, the preset reference value is 1.0. If the total voltage drop is greater than or equal to the preset voltage drop threshold, the voltage drop correction ratio of the candidate unit is obtained by combining the linear resistive voltage drop and the total voltage drop. That is, the ratio between the total voltage drop and the linear resistive voltage drop is used as the voltage drop correction ratio of the candidate unit. In a stable airflow, the value of the voltage drop correction ratio is close to 1. However, in a strong turbulent environment, due to the drastic fluctuation of current causing battery concentration polarization, the value of the voltage drop correction ratio is significantly greater than 1.

[0081] Considering the need to filter historical data similar to the planned flight path data of the planned aircraft in the current period, the parsed feature data is structured and stored in the historical database of the grid cells.

[0082] Specifically, by utilizing the drag coefficient, measured bus current, battery internal resistance, and voltage drop correction ratio of each aircraft passing through the candidate unit during historical periods, a historical characteristic record for the candidate unit is generated. This historical characteristic record can be represented as follows: ,in, This represents the b-th historical feature record corresponding to the candidate unit. This represents the drag coefficient when the i-th aircraft passes through the candidate cell within a historical time period. This represents the measured bus current when the i-th sampling aircraft passes through the candidate cell. This represents the internal resistance of the battery of the i-th sampling aircraft. This indicates the voltage sag correction ratio of the candidate cell. This indicates transpose; the first three items in the historical feature record constitute the feature vector in the historical feature record, that is: These three items represent external environmental pressure, peak task load, and battery health status, respectively; while the fourth item in the historical feature record, voltage drop correction ratio, characterizes the voltage response observed under the corresponding operating conditions. As a concrete example, all historical feature records of candidate units within a historical period constitute the candidate unit's historical database. Using the unique ID of the grid unit as the key, historical feature records are stored in the historical database of the corresponding candidate unit. As another concrete example, to ensure that the data reflects the latest microclimate conditions, the database can be maintained using a sliding time window mechanism. The system sets the effective time window length. The effective time window length can be set to 30 minutes, but implementers can adjust this setting according to specific circumstances. The system periodically checks the database, retaining only data generated before the current time. Historical feature records are stored within the database, and older records that are outside the specified time window are automatically deleted. This update mechanism ensures that the database always provides environmental and electrical coupling samples for the region at the current time, preventing outdated data from interfering with prediction accuracy.

[0083] The above methods can be used to obtain the historical database for each grid cell.

[0084] Step S3: Based on the operating condition data of the grid cells through which the planned flight path passes and the similar operating condition data in the corresponding historical database, obtain the predicted load voltage of the planned flight in the corresponding grid cell; determine the voltage-limited maximum speed corresponding to the grid cell based on the predicted load voltage.

[0085] In the above steps, a historical database for each grid cell was constructed. Next, operating condition data similar to the operating condition data of the grid cells through which the planned flight path of the planned aircraft passes during the current period will be selected to determine the voltage-limited maximum speed of the planned aircraft when it is navigating in the corresponding grid cell. Before prediction, the load level of different aircraft needs to be quantified under a unified physical framework. First, based on the energy balance equation, the baseline electrical parameters required for the planned aircraft to maintain the preset flight state under the standard linear model are calculated.

[0086] When the planning aircraft submits its flight plan, the system performs calculations for each grid cell along its planned flight path. During flight, the planning aircraft is in the level cruise phase, and the voltage response follows an ideal linear Ohm's law.

[0087] The following explanation will continue using the candidate cell as an example. The candidate cell is one of the grid cells on the planned flight path of the planned aircraft in the current time period. Other grid cells on the planned flight path can be processed using the method provided in this embodiment.

[0088] For candidate units:

[0089] First, the average drag coefficient of all candidate units in the historical database is used as the current drag coefficient of the candidate unit. Then, based on the overall efficiency of the planned aircraft's power system, battery open-circuit voltage, battery internal resistance, and reference theoretical load current, the effective mechanical power is determined. Based on the drag coefficient of the planned aircraft passing through the candidate unit, standard atmospheric density, air resistance coefficient, effective frontal reference area of ​​the planned aircraft passing through the candidate unit, and preset cruise speed, the propulsion power required to overcome air resistance is determined. Based on the battery's effective mechanical power and the propulsion power required to overcome air resistance, a power balance equation is constructed; the power balance equation can be expressed as:

[0090]

[0091] in, This indicates the overall efficiency of the planned aircraft's propulsion system. This indicates the open-circuit voltage of the planned aircraft's battery. Represents the reference theoretical load current. This indicates the internal resistance of the battery in the planned aircraft. This represents the current drag coefficient of the k-th unit. Indicates standard atmospheric density. This represents the air resistance coefficient corresponding to the planned aircraft. This represents the effective frontal reference area of ​​the planned aircraft when it passes through the k-th cell. This indicates the preset cruising speed.

[0092] Indicates effective mechanical power. This represents the propulsion power required to overcome air resistance. The baseline theoretical load current is calculated using the power balance equation; this current value represents the average supply current required if the battery exhibits only ideal linear resistive characteristics under the current wind resistance conditions.

[0093] Next, based on Ohm's law, the linear resistive voltage drop of the planned aircraft under the reference theoretical load current is calculated. Specifically, the product of the reference theoretical load current and the internal resistance of the battery of the planned aircraft is taken as the linear resistive voltage drop of the planned aircraft under the reference theoretical load current. The linear resistive voltage drop only reflects the static voltage loss caused by the internal resistance of the battery and does not include the nonlinear drop caused by environmental turbulence and polarization effects.

[0094] Considering that the current and internal resistance values ​​of different aircraft may differ by several orders of magnitude (e.g., current in the tens of amperes and internal resistance in the milliohms), directly comparing numerical differences cannot accurately measure the similarity of operating conditions. Furthermore, high loads are usually accompanied by high internal resistance and heat generation, and there is a strong statistical correlation between the variables. Therefore, this embodiment will introduce a Mahalanobis distance algorithm to screen historical samples from the historical database that have the most similar three-dimensional features of "environmental pressure-load base-battery health" to correct the prediction bias of the linear model.

[0095] For candidate units on the planned route, count the number of historical feature records in the historical database of the candidate units. ;like If the value is less than the preset statistical threshold, it indicates a lack of recent flight data in the area, and the sample size is insufficient to construct a reliable statistical distribution. In this case, the predicted voltage correction ratio is directly adjusted. Set to preset safety correction ratio The subsequent calculation of the predicted voltage correction ratio will no longer be performed. If If the value is greater than or equal to a preset statistical threshold, then the Mahalanobis distance matching calculation is performed. In this embodiment, the preset statistical threshold is 30; the preset safety correction ratio is 1.25, that is, a 25% non-linear drop safety margin is reserved.

[0096] when When the value is greater than or equal to a preset statistical threshold, a query feature vector is constructed using the current drag coefficient of the candidate unit, the baseline theoretical load current of the planned aircraft, and its battery internal resistance. The query feature vector can be represented as: ,in, This represents the query feature vector. This indicates the current drag coefficient of the candidate unit, used to reflect the aerodynamic pressure of the external environment; This represents the baseline theoretical load current of the planned aircraft, used to represent the load base required for the mission. This indicates the internal resistance of the battery in the planned aircraft, reflecting the battery's aging and health status. This indicates transpose.

[0097] A historical database is essentially a historical sample set. The covariance matrix of the historical sample set for candidate units is calculated. This matrix describes the correlation and dispersion among the various feature variables. To calculate the Mahalanobis distance, the inverse of the covariance matrix is ​​required. In practical engineering, if historical samples are highly similar, such as multiple aircraft of the same model flying in stable weather conditions, it may lead to... The determinant is close to zero, meaning the matrix is ​​singular and non-invertible. To prevent algorithm crashes, the system performs regularization before calculating the inverse matrix: [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Add a tiny preset positive number to the main diagonal elements. After regularization, the regularized covariance matrix is ​​calculated:

[0098]

[0099] in, This represents the regularized covariance matrix. Indicates a preset positive number. This represents the identity matrix. In this embodiment, In specific applications, implementers can configure it according to the specific circumstances.

[0100] After obtaining the regularized covariance matrix, calculate the regularized inverse matrix. This is used for subsequent distance calculations. The calculation of the inverse matrix is ​​a current technique and will not be elaborated on here.

[0101] In the historical database of candidate units, the statistical distance between the query feature vector and the corresponding feature vector in each historical feature record is calculated. The statistical distance can be expressed as:

[0102]

[0103] in, This represents the statistical distance between the query feature vector and the corresponding feature vector in the m-th historical feature record corresponding to the candidate unit. This represents the query feature vector. This represents the feature vector corresponding to the m-th historical feature record of the candidate unit. This represents the inverse matrix after regularization.

[0104] The smaller the statistical distance, the more similar the "environment-battery" coupled operating condition corresponding to the historical feature record is to the current planned operating condition. A preset number of historical feature records with the smallest statistical distance are selected as similar operating condition samples; in this embodiment, the preset number is 5, but in specific applications, the implementer can set it according to specific circumstances. The voltage drop correction ratio of the similar operating condition samples is weighted using the statistical distance to obtain the predicted voltage correction ratio of the planned aircraft in the candidate unit.

[0105] As a concrete example, the specific formula for calculating the predicted voltage correction ratio is given. The predicted voltage correction ratio of the planned aircraft in the candidate cell can be expressed as:

[0106]

[0107] in, This indicates the predicted voltage correction ratio of the planned aircraft in the candidate cells. This represents the statistical distance between the query feature vector and the feature vector corresponding to the m-th similar working condition sample. This indicates the number of samples with similar operating conditions. This represents the voltage drop correction ratio for the m-th similar operating condition sample.

[0108] When calculating the predicted voltage correction ratio using the above formula, if the denominator of the calculation formula is 0, then the predicted voltage correction ratio of the planned aircraft in the candidate unit is directly set to the preset safety correction ratio.

[0109] The predicted voltage correction ratio incorporates the nonlinear patterns under similar historical operating conditions, effectively compensating for the prediction errors of the linear model under the current complex coupling conditions.

[0110] The linear resistive voltage drop is corrected using the predicted voltage correction ratio. By combining the corrected linear resistive voltage drop with the open-circuit voltage of the planned aircraft's battery, the predicted load voltage of the planned aircraft in the candidate cell is obtained.

[0111] As a specific example, the predicted load voltage can be obtained as follows: calculate the product of the predicted voltage correction ratio and the linear resistive voltage drop, and use this product as the corrected linear resistive voltage drop; subtract the corrected linear resistive voltage drop from the battery open-circuit voltage of the planned aircraft as the predicted load voltage of the planned aircraft in the candidate cell. The predicted load voltage can be specifically expressed as:

[0112]

[0113] in, This indicates the predicted load voltage of the planned aircraft in the candidate cells. This indicates the open-circuit voltage of the planned aircraft's battery. This indicates the predicted voltage correction ratio of the planned aircraft in the candidate cells. This represents a linear resistive voltage drop.

[0114] This represents the corrected linear resistive voltage drop, which is an amplified correction of the ideal linear voltage drop using the predicted voltage correction ratio to reflect the additional voltage loss caused by environmental turbulence and battery polarization.

[0115] Obtain the low-voltage protection threshold of the flight control system and set a safety voltage margin. In this embodiment, the preset safety voltage margin is 0.5V. Calculate the sum of the low-voltage protection threshold and the preset safety voltage margin. If the predicted load voltage is greater than this sum, it indicates that the planned aircraft is safe to fly at the preset cruise speed. In this case, the preset cruise speed is used as the maximum voltage-limited speed. If the predicted load voltage is less than or equal to this sum, it indicates that there is a risk of low-voltage alarm when flying at the preset cruise speed. It is necessary to limit the flight speed of the planned aircraft to reduce the load current. In this case, the maximum allowable safe voltage drop of the battery can be calculated. If the maximum allowable safe voltage drop is less than or equal to 0, it indicates that the current open-circuit voltage of the battery is too low, and even without outputting current, it cannot meet the safety threshold, for example, the battery charge is extremely low. If the maximum allowable safe voltage drop is greater than 0, the maximum safe current is calculated based on the predicted voltage correction ratio, the battery internal resistance, and the maximum allowable safe voltage drop. The formulas for calculating the maximum allowable safe voltage drop of the battery and the maximum safe current at this time can be expressed as:

[0116]

[0117]

[0118] in, Indicates the maximum safe current. Indicates the maximum safe voltage drop allowed by the battery. This indicates the predicted voltage correction ratio of the planned aircraft in the candidate cells. This indicates the internal resistance of the battery in the planned aircraft. This indicates the open-circuit voltage of the planned aircraft's battery. Indicates the low-voltage protection threshold. This indicates the preset safety voltage margin.

[0119] Then, based on the maximum safe current calculated using the above formula and the current drag coefficient of the candidate unit, substitute them into the power balance equation to solve for the voltage-limited maximum speed. The voltage-limited maximum speed can be expressed as:

[0120]

[0121] in, Indicates the maximum speed limited by voltage. This indicates the overall efficiency of the planned aircraft's propulsion system. This indicates the open-circuit voltage of the planned aircraft's battery. Indicates the maximum safe current. This indicates the internal resistance of the battery in the planned aircraft. This represents the current drag coefficient of the k-th unit. Indicates standard atmospheric density. This represents the air resistance coefficient corresponding to the planned aircraft. This represents the effective frontal reference area of ​​the planned aircraft when it passes through the k-th unit.

[0122] Specifically, when using the power balance equation to solve for the voltage-limited maximum speed, if A value less than or equal to 0 indicates extremely high battery internal resistance. or maximum safe current If the battery's internal resistance loss exceeds the total output power, the battery cannot provide effective propulsion power. In this case, the voltage-limited maximum speed is directly set to 0. If the current drag coefficient of the k-th unit is less than or equal to 0, the preset zero-prevention parameter is used to replace the voltage-limited maximum speed calculation formula. Then, the calculation is performed. The preset zero-prevention parameter can be 0.1.

[0123] Using the above methods, we can obtain the voltage-limited maximum speed corresponding to each grid cell on the planned flight path. The voltage-limited maximum speed is used to describe the physical speed bottleneck that the planned aircraft needs to comply with for each segment of the planned flight path due to voltage safety constraints.

[0124] Step S4: Calculate the total travel delay time of the planned aircraft based on the maximum voltage-limited speed; adjust the actual takeoff time slot of the planned aircraft using the total travel delay time, and issue the maximum voltage-limited speed as a speed limit command to the planned aircraft.

[0125] In step S3 of this embodiment, the maximum voltage-limited speed corresponding to each grid cell on the planned route is determined. Next, the implicit dynamic speed limit is transformed into an explicit time-dimensional cost. By calculating the total travel delay time, a quantitative basis is provided for subsequent time slot allocation.

[0126] To quantify the additional airspace occupancy time of the planned aircraft due to voltage limitations, the system uses the maximum voltage-limited speed corresponding to each grid cell on the planned route to evaluate the segmented time consumption of the entire route.

[0127] For the k-th grid cell on the planned flight path, obtain the geometric path length of the planned aircraft in the k-th grid cell. For the k-th grid cell on the planned flight path, if the voltage-limited maximum speed of the k-th grid cell is less than the preset cruise speed, it indicates that there is a voltage bottleneck in the grid cell, and the aircraft needs to reduce its speed. The actual speed of the planned aircraft when passing through the k-th grid cell is the voltage-limited maximum speed of the k-th grid cell. If the voltage-limited maximum speed of the k-th grid cell is greater than or equal to the preset cruise speed, it indicates that it is safe for the planned aircraft to pass through the grid cell at the preset cruise speed, and it can cruise as planned. The actual speed of the planned aircraft when passing through the k-th grid cell is the preset cruise speed.

[0128] Furthermore, based on the geometric path length of the kth grid cell on the planned route and the actual speed of the planned aircraft when passing through the kth grid cell, the actual travel time under restricted conditions is calculated; based on the geometric path length of the kth grid cell on the planned route and the preset cruise speed, the baseline travel time under the standard plan is calculated; based on the difference between the actual travel time under restricted conditions and the baseline travel time under the standard plan, the local delay time caused by speed restriction is determined.

[0129] As a concrete example, the specific formula for calculating local delay time is given. The local delay time caused by speed limitation in the k-th grid cell on the planned route can be expressed as:

[0130]

[0131] in, This represents the local delay time caused by speed limitation within the k-th grid cell on the planned flight path. This represents the geometric path length of the k-th grid cell on the planned route. This represents the velocity of the planned aircraft when it passes through the k-th grid cell. This indicates the preset cruising speed.

[0132] This indicates the actual travel time under restricted conditions. This indicates the baseline travel time under the standard plan.

[0133] The total travel delay time is obtained by summing the local delay times caused by speed limitations within all grid cells along the planned flight path. This total travel delay time reflects the rigid time cost that the planned aircraft needs to incur to maintain voltage safety throughout the entire flight. This time difference, the total travel delay time, is the core basis for subsequent adjustments to departure time slots, ensuring that slow-speed flights do not encroach on the time windows of subsequent aircraft.

[0134] To prevent planned aircraft from becoming a mobile bottleneck and obstructing traffic flow due to slow-speed flight, the system dynamically postpones the departure slot based on the duration of traffic delay, moving the aircraft from high-density airspace periods to time windows that can accommodate its low-speed operation.

[0135] If the total delay exceeds the preset maximum allowable delay threshold, or if the voltage limitation maximum speed of any grid cell is zero, it indicates that the current airspace environment is extremely harsh or the battery condition is too poor. Even if the departure is postponed, basic passage efficiency cannot be guaranteed, and there is a significant safety hazard. In this case, the system triggers the access circuit breaker mechanism, rejects the flight plan application, and sends an alarm to the operator, suggesting that the battery be replaced with a fully charged one or that the route be replanned to avoid the high impedance area. In this embodiment, the preset maximum allowable delay threshold is 10 minutes, which represents the airspace system's minimum tolerance for the efficiency of a single flight.

[0136] If the total delay is less than or equal to the preset maximum allowable delay threshold, it indicates that the delay is within a controllable range, and the subsequent time slot adjustment process continues. Specifically, the baseline departure time slot originally allocated to the planned aircraft is obtained. To ensure that the planned aircraft maintains a sufficient safe distance from subsequent aircraft while flying at a limited speed throughout the entire journey, the system postpones the baseline departure time slot. The postponement includes not only the rigid delay duration but also a preset safety buffer time. As a specific example, the total delay duration is added to the preset buffer time to obtain the total adjustment time. In this embodiment, the preset buffer time is 30 seconds, used to cover any additional errors that may occur during takeoff and landing. The original baseline departure time slot of the planned aircraft is postponed by the total adjustment time to obtain the adjusted actual takeoff time slot. This adjustment allows for a longer virtual pipeline to be reserved for the planned aircraft in terms of timing, ensuring that it will not encroach on the original time slot of subsequent aircraft when it decelerates due to voltage limitations in any grid.

[0137] Considering that adjusting the departure time is not enough during the flight of an aircraft, it is also necessary to ensure that the aircraft strictly adheres to the calculated speed limit in the air in order to truly avoid low-pressure alarms.

[0138] Therefore, the voltage-limited maximum speed of each grid cell on the planned route calculated in step S3 is geographically mapped to the route trajectory points, and packaged into a waypoint speed limit instruction package. This instruction contains a series of "geofence-maximum speed" key-value pairs, which explicitly specify the maximum ground speed allowed for the aircraft when flying over each grid cell.

[0139] Before the planned aircraft receives takeoff clearance, the system uploads the instruction packet to its onboard flight management system via a ground-to-air data link. During actual flight, when the planned aircraft enters each grid cell, the onboard flight management system executes the following steps: Autopilot mode: The flight management system uses the voltage-limited maximum speed as the speed limit constraint for the current flight segment, automatically limiting the motor power output to ensure that the flight speed does not exceed this value. Manual piloting mode: The flight management system displays a maximum permissible speed warning box on the main flight display and triggers tactile or audible alarms when the speed approaches the voltage-limited maximum speed, prompting the pilot to stop accelerating. This feedforward mechanism enables the aircraft to actively limit power output when encountering strong headwinds or high-impedance environments, thereby avoiding the flight control system drawing large currents to maintain the planned high speed and effectively preventing the risk of in-flight emergency shutdown caused by the battery voltage dropping below the low-voltage protection threshold.

[0140] This embodiment collects actual flight data, electrical bus data, and aerodynamic parameters of the sampling aircraft during the level flight cruise phase. It can extract the drag coefficient and voltage drop correction ratio, which reflect the influence of airflow in specific grid cells. This enables the quantification of the complex aerodynamic environment and battery electrical response characteristics in urban low-altitude areas, providing a reliable environmental and electrical coupling data foundation for subsequent predictions. Based on the drag coefficient, voltage drop correction ratio, and electrical data in the historical database, combined with the operating conditions of the grid cells traversed by the currently planned aircraft route, it can predict the load voltage in each grid cell. This predicted value is then used to further determine the maximum voltage-limited speed of each cell. This enables the early identification and quantitative assessment of the risk of battery voltage drop caused by environmental turbulence during flight, improving the voltage safety prediction capability of the aircraft in complex airflow environments. Based on the maximum voltage-limited speed, the total travel delay time caused by the speed limitation of the planned aircraft is derived, and its actual takeoff time slot is adjusted accordingly. At the same time, a speed limit command is issued to the aircraft. This method can adapt to the dynamic changes in the urban low-altitude environment, realize personalized safety management and control of different aircraft, and dynamically optimize and safely allocate airspace resources, avoid safety problems caused by abnormal deceleration in the air due to voltage drops, and improve the efficiency of airspace passage.

[0141] Example of an airspace resource optimization and allocation system for low-altitude urban flight:

[0142] See Figure 2 The diagram illustrates a structural block diagram of an airspace resource optimization and allocation system for urban low-altitude flight according to an embodiment of the present invention. The system may include a data acquisition module, a historical database construction module, a maximum speed determination module, and an adjustment module.

[0143] The data acquisition module is used to acquire actual flight data, electrical bus data and aerodynamic parameters of the sampling aircraft during the level flight cruise phase.

[0144] The historical database construction module is used to obtain the drag coefficient and voltage sag correction ratio of the sampled aircraft when passing through each grid cell based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during the historical period; and to construct the historical database of each grid cell using the drag coefficient, voltage sag correction ratio and electrical bus data during the historical period.

[0145] The maximum speed determination module is used to obtain the predicted load voltage of the planned aircraft in the corresponding grid cell based on the operating condition data of the grid cell through which the planned flight path passes and the similar operating condition data in the corresponding historical database; and to determine the voltage-limited maximum speed corresponding to the grid cell based on the predicted load voltage.

[0146] The adjustment module is used to calculate the total travel delay time of the planned aircraft based on the voltage-limited maximum speed; adjust the actual takeoff time slot of the planned aircraft using the total travel delay time; and issue the voltage-limited maximum speed as a speed limit command to the planned aircraft.

[0147] It should be understood that Figure 2 The structural block diagram and modules of the airspace resource optimization and allocation system for low-altitude urban flight shown can be implemented in various ways. For example, in some embodiments, the system and its modules can be implemented by hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by appropriate instructions, such as a microprocessor or dedicated hardware. Those skilled in the art will understand that the above-described methods and apparatus can be implemented using computer-executable instructions and / or included in processor control code, for example, on a media such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The apparatus and modules described in this specification can be implemented not only by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., but also by software executed by various types of processors, or by a combination of the above-described hardware circuits and software (e.g., firmware).

[0148] For more details about the above modules, please refer to other parts of this manual; they will not be repeated here.

[0149] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing the allocation of airspace resources for low-altitude urban flight, characterized in that, The method includes the following steps: Acquire actual flight data, electrical bus data, and aerodynamic parameters of the sampling aircraft during the level flight cruise phase; Based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during historical periods, the drag coefficient and voltage sag correction ratio of the sampled aircraft when passing through each grid cell are obtained; and a historical database of each grid cell is constructed using the drag coefficient, voltage sag correction ratio and electrical bus data during historical periods. Based on the operating condition data of the grid cells traversed by the planned flight path of the planned aircraft and the similar operating condition data in the corresponding historical database, the predicted load voltage of the planned aircraft in the corresponding grid cell is obtained; based on the predicted load voltage, the voltage-limited maximum speed corresponding to the grid cell is determined. The total travel delay time of the planned aircraft is calculated based on the voltage-limited maximum speed; the actual takeoff time slot of the planned aircraft is adjusted using the total travel delay time, and the voltage-limited maximum speed is issued to the planned aircraft as a speed limit command.

2. The airspace resource optimization allocation method for urban low-altitude flight according to claim 1, characterized in that, The acquisition of the drag coefficient and voltage drop correction ratio of the sampling aircraft as it passes through each grid cell includes: The electrical bus data includes battery open-circuit voltage, battery internal resistance, measured bus voltage, and measured bus current. Based on the actual flight data of the sampling aircraft during its flight in the candidate unit, the power component of the sampling aircraft's work against gravity is determined; based on the law of conservation of energy, the actual mechanical thrust is determined using the power component and the mass of the sampling aircraft; based on the aerodynamic parameters of the sampling aircraft and the actual flight data, the theoretical reference thrust is obtained. The ratio of the actual mechanical thrust to the theoretical reference thrust is determined as the drag coefficient of the sampling aircraft when it passes through the candidate unit; Based on Ohm's law, and using the battery's internal resistance and the measured bus current, the linear resistive voltage drop is obtained. By combining the linear resistive voltage drop and the total voltage drop from the battery open-circuit voltage to the measured bus voltage, the voltage drop correction ratio when the sampling aircraft passes through the candidate unit is obtained; The candidate cell can be any grid cell.

3. The airspace resource optimization allocation method for urban low-altitude flight according to claim 2, characterized in that, The historical database for each grid cell is constructed using drag coefficients, voltage sag correction ratios, and electrical bus data from historical time periods, including: By utilizing the drag coefficient, measured bus current, battery internal resistance, and voltage drop correction ratio of each sampled aircraft when passing through the candidate unit during historical periods, historical feature records of the candidate unit are generated; all the historical feature records of the candidate unit constitute the historical database of the candidate unit.

4. The airspace resource optimization allocation method for urban low-altitude flight according to claim 3, characterized in that, The step of obtaining the predicted load voltage of the planned aircraft in the corresponding grid cell based on the operating condition data of the grid cells traversed by the planned flight path and similar operating condition data in the corresponding historical database includes: For candidate units: Based on the effective mechanical power of the battery corresponding to the planned aircraft and the propulsion power required to overcome air resistance, a power balance equation is constructed; the reference theoretical load current is solved using the power balance equation; the effective mechanical power is determined based on the overall efficiency of the power system, the battery open-circuit voltage, the battery internal resistance, and the reference theoretical load current; the propulsion power required to overcome air resistance is determined based on the drag coefficient, standard atmospheric density, air resistance coefficient, effective frontal reference area, and preset cruise speed of the planned aircraft when passing through the candidate unit; Calculate the linear resistive voltage drop of the planned aircraft under the baseline theoretical load current; A query feature vector is constructed using the current drag coefficient of the candidate unit, the baseline theoretical load current of the planned aircraft, and its battery internal resistance; the current drag coefficient of the candidate unit is the average of all drag coefficients of the aircraft when it passes the candidate unit in the historical database; In the historical database of the candidate unit, the statistical distance between the query feature vector and the corresponding feature vector in each historical feature record is calculated; a preset number of historical feature records with the smallest statistical distance are selected as similar working condition samples. The voltage drop correction ratio of the similar operating condition samples is weighted using the statistical distance to obtain the predicted voltage correction ratio of the planned aircraft in the candidate unit. The linear resistive voltage drop is corrected using the predicted voltage correction ratio. The corrected linear resistive voltage drop is then combined with the open-circuit voltage of the planned aircraft's battery to obtain the predicted load voltage of the planned aircraft in the candidate unit.

5. The airspace resource optimization allocation method for urban low-altitude flight according to claim 4, characterized in that, The step of correcting the linear resistive voltage drop using the predicted voltage correction ratio, and combining the corrected linear resistive voltage drop with the open-circuit voltage of the planned aircraft's battery, to obtain the predicted load voltage of the planned aircraft in the candidate cell includes: The product of the predicted voltage correction ratio and the linear resistive voltage drop is taken as the corrected linear resistive voltage drop. The difference between the battery open-circuit voltage of the planned aircraft and the corrected linear resistive voltage drop is used as the predicted load voltage of the planned aircraft in the candidate cell.

6. The airspace resource optimization allocation method for urban low-altitude flight according to claim 5, characterized in that, The process of determining the voltage-constrained maximum speed corresponding to a grid cell based on the predicted load voltage includes: Calculate the sum of the low-voltage protection threshold and the preset safety voltage margin; If the predicted load voltage is greater than the sum of the values, then the preset cruising speed will be used as the maximum speed limited by the voltage. If the predicted load voltage is less than or equal to the sum of the values, the maximum safe current is calculated based on the predicted voltage correction ratio, the battery internal resistance, and the maximum allowable safe voltage drop; the voltage-limited maximum speed is solved by the power balance equation based on the maximum safe current and the current drag coefficient of the candidate cell.

7. The method for optimizing airspace resource allocation for urban low-altitude flight according to claim 1, characterized in that, The calculation of the planned flight delay time based on the voltage-limited maximum speed includes: For each grid cell on the planned route, the local delay time caused by speed limitation in each grid cell is calculated based on the geometric path length, preset cruise speed, and the voltage-limited maximum speed of each grid cell. The total travel delay time is obtained by summing the local delay times of all grid cells on the planned route.

8. The method for optimizing airspace resource allocation for urban low-altitude flight according to claim 1, characterized in that, Before adjusting the actual takeoff time slot of the planned aircraft, a circuit breaker determination step is also included: If the total travel delay exceeds the preset maximum allowable delay threshold, or if the voltage limit of any grid cell is zero, then the current flight plan of the aircraft will be rejected.

9. The method for optimizing airspace resource allocation for urban low-altitude flight according to claim 1, characterized in that, The method of adjusting the actual takeoff time slot of the planned aircraft using the total travel delay time includes: The total adjustment time is obtained by adding the total delay time to the preset buffer time; The original planned base departure time slot of the planned aircraft is postponed by the total adjustment time to obtain the adjusted actual takeoff time slot.

10. A system for optimizing and allocating airspace resources for low-altitude urban flight, the system being used to execute the method of claim 1, characterized in that, The system includes: The data acquisition module is used to acquire actual flight data, electrical bus data, and aerodynamic parameters of the sampling aircraft during the level flight cruise phase of flight. The historical database construction module is used to obtain the drag coefficient and voltage sag correction ratio of the sampled aircraft when passing through each grid cell based on the actual flight data and aerodynamic parameters of the sampled aircraft in each grid cell during the historical period; and to construct the historical database of each grid cell using the drag coefficient, voltage sag correction ratio and electrical bus data during the historical period. The maximum speed determination module is used to obtain the predicted load voltage of the planned aircraft in the corresponding grid cell based on the operating condition data of the grid cell through which the planned flight path passes and the similar operating condition data in the corresponding historical database; and to determine the voltage-limited maximum speed corresponding to the grid cell based on the predicted load voltage. The adjustment module is used to calculate the total travel delay time of the planned aircraft based on the voltage-limited maximum speed; adjust the actual takeoff time slot of the planned aircraft using the total travel delay time; and issue the voltage-limited maximum speed as a speed limit command to the planned aircraft.

Images