A multi-mode air data system for an electric vertical takeoff and landing aircraft and method of operation

Abstract

The application relates to the field of avionics, and is a multi-mode atmospheric data system and working method for an electric vertical take-off and landing aircraft, specifically comprising: a triple-redundancy atmospheric data system, a flight control computer and a display control system. The flight control computer generates a mode criterion according to a motor tilting angle or a working state, determines a rotor mode, a transition mode and a cruising mode through a hysteresis threshold and a holding time, and issues a mode state word and parameter enabling information. Each atmospheric data computer performs differential analysis according to the current mode, and outputs corresponding atmospheric parameters and validity state words. The flight control computer performs consistency checking, voting fusion and degradation management on the current enabled parameters, and sends the voted parameters, three sets of original parameters and redundancy states to the display control system. The application reduces the control risk of misleading atmospheric data in the full envelope operation of the eVTOL aircraft, and improves the system safety.

Description

Technical Field

[0001] This invention relates to the field of avionics technology, and is a multi-mode atmospheric data system and its operating method for electric vertical takeoff and landing aircraft. Background Technology

[0002] Electric vertical takeoff and landing (eVTOL) aircraft are a new type of aircraft that combines the vertical takeoff and landing capabilities of helicopters with the high-speed cruise capabilities of fixed-wing aircraft. Their typical flight missions include not only rotor mode and cruise mode, but also transitional modes with rapidly changing aerodynamic environments, low dynamic pressure, and downwash.

[0003] Traditional air data systems are primarily designed for fixed-wing aircraft or helicopters operating in a single flight mode. For eVTOL aircraft, if a complete set of atmospheric parameters (such as airspeed, angle of attack, and sideslip angle) is continuously output throughout the entire flight, significant problems arise in rotor mode and transition mode: First, at low speeds or while hovering, the airspeed signal itself is very small, and the definition and physical meaning of parameters such as angle of attack and sideslip angle change, leading to a sharp decline in sensor measurement accuracy and reliability, resulting in high noise and low reliability of the output values. Second, in transition mode, downwash, changes in airframe attitude, and complex flow fields can cause short-term parameter jumps. Without hysteresis switching, validity status, and degradation management, misleading air data can be easily provided to the flight control and display systems.

[0004] Therefore, an atmospheric data system is needed that can intelligently identify rotor, transition, and cruise phases and dynamically adjust parameter output content, validity status, and voting strategies to meet the stringent requirements of eVTOL aircraft for data reliability, security, and system efficiency during full envelope flight. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] To address the problems existing in the prior art as pointed out in the background section, the present invention provides a multi-mode atmospheric data system for electric vertical takeoff and landing aircraft, comprising: The triple-redundant atmospheric data system includes a first atmospheric data computer, a second atmospheric data computer, and a third atmospheric data computer. Each atmospheric data computer is connected to a corresponding sensor to receive the mode status word and execute the differential calculation strategy according to the current flight phase, and output the corresponding set of atmospheric parameters and its validity status word. The flight control computer communicates with each atmospheric data computer to generate and send mode criteria. Based on the mode criteria, it determines the current flight phase through hysteresis threshold and hold-up time conditions and generates mode status words and parameter enable information. Based on the parameter enable information, it performs consistency checks and voting fusion on the triple redundancy measurements from the three atmospheric data computers to generate the voted atmospheric parameters and their final validity status. The display control system is communicatively connected to the flight control computer and is used to receive and display the atmospheric parameters after voting and their final validity status. It also receives and displays the original atmospheric parameters output by each atmospheric data computer, the validity status words corresponding to the original atmospheric parameters, and the parameter differences between pairs of redundancies.

[0007] In addition, the present invention provides a method for operating a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft, comprising: The flight control computer generates motor control commands based on the flight plan and the real-time status of the aircraft, extracts the motor tilt angle or motor operating status from the motor control commands as mode criteria, and sends the mode criteria to the first atmospheric data computer, the second atmospheric data computer and the third atmospheric data computer; The flight control computer determines the mode based on the mode criteria, using a preset hysteresis threshold and hold-up time condition, generates the mode status word and parameter enable information corresponding to the current flight phase, and sends the mode status word and parameter enable information to each atmospheric data computer. Each atmospheric data computer executes a differential resolution strategy that matches the current flight phase based on the received mode status word, outputs the corresponding set of atmospheric parameters, and adds a validity status word to each output atmospheric parameter. The flight control computer, based on the parameter enable information, filters the atmospheric parameters enabled in the current flight phase, performs consistency checks and voting fusion on the triple redundancy measurement values ​​from the three atmospheric data computers, and generates the voted atmospheric parameters and their corresponding final validity status. The flight control computer sends the voted atmospheric parameters to the display control system, and at the same time sends the original atmospheric parameters output by each atmospheric data computer, the validity status words corresponding to the original atmospheric parameters, and the parameter differences between each pair of redundancies to the display control system for comprehensive display and fault diagnosis.

[0008] Preferably, the mode determination specifically includes: The flight control computer pre-sets a first threshold and a second threshold, wherein the first threshold is greater than the second threshold, and sets a holding time. When the duration for which the motor tilt angle is less than or equal to the first threshold reaches the holding time, the current mode switches from rotor mode to transition mode; When the duration for which the motor tilt angle is greater than or equal to the first threshold reaches the holding time, the current mode is switched from the transition mode to the rotor mode; When the duration for which the motor tilt angle is less than or equal to the second threshold reaches the holding time, the current mode is switched from the transition mode to the cruise mode; When the duration for which the motor tilt angle is greater than or equal to the second threshold reaches the holding time, the current mode switches from the cruise mode to the transition mode; When the motor tilt angle is between the second threshold and the first threshold, the current mode remains the transition mode.

[0009] Preferably, the differential resolution strategy includes: In the rotor mode, each atmospheric data computer outputs static pressure, total temperature, and pressure altitude, and marks the validity status words of vacuum speed, angle of attack, and sideslip angle as failed; In the transition mode, each air data computer outputs at least static pressure, total temperature, and pressure altitude. When the dynamic pressure is greater than a preset dynamic pressure threshold and the airspeed difference between two air data computers is less than a preset consistency threshold, the validity status word of the airspeed parameter is marked as valid; otherwise, it is marked as downgraded or invalid. In the cruise mode, each atmospheric data computer outputs static pressure, dynamic pressure, total temperature, barometric altitude, vacuum velocity, angle of attack, and sideslip angle, and marks the validity status of all parameters as valid.

[0010] Preferably, the consistency check and voting fusion specifically includes: The flight control computer calculates the pairwise differences between three measured values ​​of the same parameter output by the three air data computers and compares each difference with a preset threshold. When all differences are less than the threshold, the median of the three measurements is taken as the voting result. When only one set of differences is less than the threshold, the third redundancy is isolated, and the average of the two measurements that pass the consistency check is taken as the voting result. When all three differences are not less than the threshold, a weighted fusion algorithm is used to calculate the voting result, and the voting result is marked as downgraded.

[0011] Preferably, in the weighted fusion algorithm, the initial weight values ​​of each redundancy are all set to be equal; When a certain redundancy is marked as degraded, the weight of that redundancy decays exponentially. When a certain redundancy passes the consistency check consecutively and the state is restored to validity, the weight of that redundancy is gradually restored to its initial value; Each weight change is recorded in non-volatile memory.

[0012] Preferably, after generating the atmospheric parameters after voting and their corresponding final validity status, the process also includes: degradation and failure management, as detailed below: When the signal source of an atmospheric parameter is in transition mode, partially redundant, or the triple redundancy measurements are inconsistent, the flight control computer marks the final validity state of the parameter as downgraded and reduces the influence weight of the parameter in the flight control law. When all redundancies are marked as invalid or communication is completely interrupted, the flight control computer marks the final validity state of the parameter as invalid and reconstructs the flight state based on the inertial navigation parameters.

[0013] Preferably, when the mode criterion is abnormal, the communication between the flight control computer and the air data computer is interrupted, or the quality index of the air parameters is lower than a preset threshold, the flight control computer will switch the corresponding parameters to a degraded or failed state, and maintain the basic air parameters output of static pressure, total temperature, and air pressure altitude.

[0014] Preferably, the display control system displays the atmospheric parameters after the vote and their final validity status on the main flight display page, and displays the original atmospheric parameters output by the three atmospheric data computers, the validity status words corresponding to each original atmospheric parameter, and the parameter differences between each pair of redundancies on the system status display page.

[0015] Preferably, the flight control computer starts a communication monitoring timer while sending the mode criteria to each atmospheric data computer; If no response confirmation signal is received from any of the air data computers within multiple consecutive transmission cycles, the communication link is determined to be abnormal, and the flight control computer immediately sends the mode status word to the backup enable port of each air data computer via the backup discrete signal line.

[0016] Compared with the prior art, the technical effects of the present invention are as follows: 1. This invention uses the motor tilt angle or motor operating state as the mode criterion. This criterion is directly derived from the motor control command generated by the flight control computer and does not rely on easily disturbed atmospheric parameters such as airspeed and dynamic pressure. This avoids the problem of mode misjudgment caused by atmospheric data measurement deviation in traditional solutions, and ensures the reliability of the mode switching trigger source and the accuracy of mode determination.

[0017] 2. This invention employs a heterogeneous triple-redundant atmospheric data sensing architecture consisting of a first five-hole probe, a second five-hole probe, a total hydrostatic pitot tube, and an angle sensor. Combined with central-level voting and degradation management of the flight control computer, it performs pairwise consistency checks and multi-level voting fusion on the triple-redundant atmospheric data. Degradation and failure management are implemented based on the validity status words of each redundancy, effectively avoiding the risk of simultaneous failure of multiple redundancies due to common cause failures. This ensures that reliable atmospheric data can still be output for use by the flight control system under single-redundancy or multi-redundancy failure conditions.

[0018] 3. This invention formulates differentiated parameter calculation and output strategies for rotor mode, transition mode and cruise mode respectively. In rotor mode, it actively suppresses the output of low-reliability parameters such as airspeed, angle of attack and sideslip angle and marks them as failures. In transition mode, it conditionally outputs airspeed parameters only when the dynamic pressure and consistency check conditions are met. In cruise mode, it outputs a complete set of atmospheric parameters. This cuts off the propagation path of misleading data into the flight control main link from the source and significantly reduces the control risk caused by misleading atmospheric data in the full envelope operation of eVTOL aircraft. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments 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. Wherein: Figure 1 This is a schematic diagram of the hardware architecture and data flow of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to the present invention. Figure 2 This is a flowchart illustrating the working method of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to the present invention. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "example" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The appearance of an embodiment in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that mutually excludes other embodiments.

[0023] Example 1: like Figure 1 As shown, an embodiment of the present invention provides a multi-mode atmospheric data system for an electric vertical takeoff and landing (eVTOL) aircraft. The system mainly includes: a heterogeneous triple redundancy atmospheric data sensor and computer assembly, a flight control computer, and a display control system 400.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "communication connection" and "electrical connection" should be interpreted broadly. For example, they can refer to aviation data bus connections such as ARINC429, CAN bus, RS-485, and avionics Ethernet, or wireless communication connections. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Furthermore, the ordinal numbers such as first and second mentioned in subsequent embodiments are only used to distinguish different components or signals and should not be construed as limiting their importance, priority, or physical location.

[0026] In a more specific embodiment, such as Figure 1 As shown, the heterogeneous triple-redundant atmospheric data sensor and computer assembly specifically include: The first atmospheric data redundancy consists of the first five-hole probe 101 and the first atmospheric data computer 201 connected to it via the gas path.

[0027] The first five-hole probe 101 is preferably installed on one side of the aircraft nose, and its five pressure holes are used to sense the total pressure, static pressure and pressure difference in the vertical and horizontal directions of the incoming flow.

[0028] The second atmospheric data redundancy consists of the second five-hole probe 102 and the second atmospheric data computer 202 connected to it via the gas path.

[0029] The second five-hole probe 102 is preferably installed symmetrically with the first five-hole probe 101 on the other side of the aircraft nose, forming symmetrical redundancy.

[0030] The third atmospheric data redundancy consists of sensor 103 and third atmospheric data computer 203, wherein sensor 103 includes: total static airspeed tube and angle sensor; The total static pressure pitot tube is used to sense the total pressure and static pressure of the incoming flow. The angle sensor is preferably an embedded wind vane sensor or a MEMS-based thermal angle sensing chip, which is used to directly sense the local angle of attack and local sideslip angle of the incoming flow relative to the aircraft body, and convert them into analog or digital electrical signals, which are then sent to the third atmospheric data computer 203 for acquisition.

[0031] This heterogeneous design avoids common-cause failures and improves system robustness.

[0032] Each of the atmospheric data computers 201, 202, and 203 contains at least one processor, memory, pressure sensor interface, temperature sensor interface, and data bus interface.

[0033] The Flight Control Computer 300 is a highly complete, multi-core flight control core processing unit that internally runs flight control laws, atmospheric data voting and management modules, and mode management logic.

[0034] The flight control computer 300 is cross-connected with three air data computers 201, 202, and 203 and the display control system 400 through one or more redundant aviation data buses to ensure high reliability of the communication link.

[0035] Example 2: like Figure 2 As shown below, in conjunction with Figure 2 The flowchart shown provides a detailed explanation of the multi-mode atmospheric data working method of this invention. S1: The flight control computer 300 generates motor tilt angle commands based on the flight plan and aircraft status as mode criteria, and periodically sends them to three air data computers via the aviation data bus, as follows: As the core of the aircraft's overall flight management, the flight control computer 300 is responsible for generating mode criteria. Specifically, based on the preset flight management plan and the real-time aircraft status, the flight control computer 300 calculates and generates motor control commands for controlling the eVTOL aircraft's power units (such as tilt rotors, lift fans, etc.).

[0036] This instruction includes not only the motor speed, but also the target tilt angle of the motor. Or a discrete state word that represents its working state.

[0037] Flight control computer 300 directly this Alternatively, its corresponding status indicator signal can be extracted and used as a mode criterion. It should be noted that this criterion no longer relies on indirect or easily disturbed atmospheric parameters, thus fundamentally ensuring the reliability of the triggering source.

[0038] Subsequently, the flight control computer 300 packages the mode criterion into a standard data frame and periodically sends it to the first air data computer 201, the second air data computer 202, and the third air data computer 203 via the airborne data bus. The transmission period is preferably 10 milliseconds to 50 milliseconds to ensure the real-time nature of mode switching.

[0039] Simultaneously, during the transmission mode determination process, the flight control computer (300) activates a bus communication monitoring timer. If no acknowledgment signal is received from any of the three air data computers within three consecutive transmission cycles, the communication link is deemed abnormal.

[0040] At this time, the flight control computer (300) will immediately activate the internally preset safety mode (the default is to rotor mode) and immediately send the mode status word directly to the backup enable input port of each air data computer through an independent backup discrete signal line to ensure that the mode information is not lost due to bus failure.

[0041] S2: The flight control computer uses the built-in hysteresis threshold and hold-up time logic to determine anti-interference capabilities, generates the final mode status word and corresponding parameter enable information, and sends it to the three air data computers.

[0042] This step is the core of the invention's multi-mode stable switching, and it is executed entirely within the flight control computer 300. The flight control computer 300 receives the mode criterion it generates. Subsequently, it is not used directly, but is processed through a logic unit containing hysteresis thresholds and hold-time conditions to generate the final flight mode status word. And the corresponding parameter enable information.

[0043] Specifically, the determination process includes the following sub-steps: S201: Pre-store the thresholds and conditions required for mode switching in the non-volatile memory of the flight control computer, and define the angle. Set a first threshold and a second threshold for the angle between the motor axis and the vertical direction (Z-axis) of the aircraft, and define the holding time. It is used to filter out momentary jitter.

[0044] A set of thresholds and conditions are pre-stored in the non-volatile memory of the flight control computer 300. In a preferred embodiment, the angle is defined. The angle between the motor thrust axis and the aircraft's horizontal reference plane is defined as follows: In rotor mode (vertical takeoff and landing)... When approaching 90° (large tilt angle), in cruise mode (level flight) Approaching 0° (small tilt angle). Accordingly, the first threshold is defined as... The second threshold is ,and .For example, Setting it to 70° represents the boundary for transitioning from rotor mode to transition mode; Setting it to 20° represents the boundary between transition mode and cruise mode.

[0045] At the same time, define a hold time. The preferred value range is 0.5 seconds to 2 seconds. For example, it can be set to 1 second. It should be noted that this hold time setting is to filter out instantaneous angle jumps caused by command jitter, turbulence or sensor noise, so as to avoid mode switching.

[0046] The aforementioned , and All parameters are configurable and stored in a dedicated parameter table in the non-volatile memory of the flight control computer 300. Ground maintenance personnel can modify them online in ground condition (determined by landing gear compression signals or wheel signals) through the ground maintenance terminal. Once the aircraft enters the takeoff roll or takeoff flight phase, the system automatically locks the write access to the above parameters and prohibits any in-flight rewriting operations to prevent accidental operation from causing mode switching disorder.

[0047] S202: Within each calculation cycle, the flight control computer adjusts the current mode... and The time for continuously satisfying the conditions is determined as follows: The flight control computer 300 performs the following logical judgment in each calculation cycle, such as 10 milliseconds: If the current mode It is in rotor mode, and Continuously less than or equal to the first threshold Time reached Then the target pattern Set to transition mode; Otherwise, keep constant.

[0048] If the current mode Transition mode: like Continuously greater than or equal to the first threshold Time reached ,but Set to rotor mode.

[0049] like Continuously less than or equal to the second threshold Time reached ,but Set to cruise mode.

[0050] like Between and Between, Maintain in transition mode.

[0051] If the current mode It is in cruise mode, and Continuously greater than or equal to the second threshold Time reached ,but Set to transition mode; Otherwise, keep constant.

[0052] This logic introduces a return hysteresis, with the threshold for the tangential transition from the rotor being... The threshold for transitioning back to the rotor is also... This constitutes a hysteresis at a single threshold; more preferably, the threshold for the tangential transition from cruise is... The threshold for transitioning to tangential cruise is also... This symmetrical threshold setting, combined with the hold time, constitutes a complete anti-interference mechanism.

[0053] S203: Once Upon confirmation of the update, the flight control computer 300 generates a dedicated data packet containing the mode status word.

[0054] The data packet also implicitly or explicitly contains parameter enabling information, which clearly indicates which atmospheric data parameters are enabled, degraded, or inhibited in rotor mode, transition mode, and cruise mode.

[0055] The flight control computer 300 sends the data packet in parallel to three air data computers.

[0056] S3: Based on the received mode status words, the three air data computers execute differentiated calculation strategies for the rotor, transition, and cruise modes respectively, output the corresponding air data parameters, and attach validity status words indicating validity, degradation, and failure.

[0057] After receiving the mode status word from the flight control computer 300, the three air data computers, as the main implementers of this step, drive their respective connected sensors to execute the differential calculation strategy that matches the current mode.

[0058] Each atmospheric parameter output by an atmospheric data computer will be appended with a validity status word, which includes at least three states: valid, degraded, and invalid.

[0059] The behavior is defined in the specific mode as follows: S301: When the rotor mode command is received, the aircraft is in the vertical takeoff and landing, hovering, or low-speed flight phase. At this time, the incoming airflow direction is turbulent, the dynamic pressure is extremely low, the physical definitions of angle of attack and sideslip angle are ambiguous, and the measurement signal-to-noise ratio is extremely low.

[0060] Therefore, each atmospheric data computer enters the first calculation mode.

[0061] In this mode: Enabled and output parameters: static pressure Total temperature And the pressure altitude calculated from static pressure using the standard atmospheric model. .

[0062] The formula for calculating air pressure altitude can be the tropospheric formula from the International Standard Atmosphere (ISA) model: ; In the formula, The standard temperature at sea level Standard atmospheric pressure at sea level. This represents the vertical temperature lapse rate. The gas constant of air. This is the acceleration due to gravity.

[0063] Parameters that suppress or disable output: for vacuum speed Angle of attack Sideslip angle For these low-reliability parameters, the atmospheric data computer actively sets their output value to zero or retains the last valid value, and marks their validity status as invalid.

[0064] This move cuts off the transmission chain of misleading data at its source, preventing downstream systems from misusing it.

[0065] S302: When the transition mode command is received, the aircraft is in a dynamic transition phase between rotor and fixed-wing flight states. The flow field is complex, the downwash and incoming flow are coupled, and atmospheric parameters change drastically.

[0066] Each atmospheric data computer enters the second processing mode, adopting a gradual and conservative output strategy: Unconditionally enabled and output basic parameter: static pressure Total temperature and air pressure altitude .

[0067] These parameters are crucial for flight safety and are insensitive to the direction of incoming flow, thus maintaining a stable and effective output at all times.

[0068] Conditionally enabled and output airspeed parameters: For indicated airspeed Vacuum speed The atmospheric data will be continuously processed by the computer, but the assignment of its validity status word depends on the judgment of one or more threshold conditions. Specific conditions include: Dynamic pressure threshold: The total pressure measured in real time by the total pressure tube (or the center hole of the five-hole probe) is acquired by the atmospheric data computer. And calculate the dynamic pressure .when Greater than the preset dynamic pressure threshold (For example When the airspeed parameters were initially determined to be valid, it was determined that they had a basis for validity.

[0069] Consistency check threshold: When the airspeed difference calculated by the first atmospheric data computer 201 and the second atmospheric data computer 202... Less than the preset consistency threshold (For example, When this is done, the credibility of the data should be further confirmed.

[0070] The airspeed parameter's validity status word is set to valid only when all the above conditions are met; if some conditions are not met, it is marked as downgraded; if the dynamic pressure is lower than... If the cross comparison fails, it is marked as invalid.

[0071] In this mode, angle of attack and sideslip angle are usually marked as failed or downgraded due to low reliability and are not used as the main control basis.

[0072] S303: When a cruise mode command is received, the motor tilts to a small angle or a horizontal state, and the aircraft cruises at high speed in a fixed-wing configuration. At this time, the flow field is stable, and atmospheric data measurement enters the ideal working range.

[0073] It should be noted that this system adopts a heterogeneous sensor architecture: both the first atmospheric data computer 201 and the second atmospheric data computer 202 are connected to five-hole pressure probes to acquire multi-dimensional pressure field information; the third atmospheric data computer 203 is connected to a hydrostatic pitot tube, which integrates an angle sensor to measure local flow direction. Based on this hardware difference, the following differential analysis is performed in cruise mode, as follows: Each atmospheric data computer enters the third calculation mode, activating all its calculation functions and outputting a complete set of atmospheric parameters. The validity status words of all parameters are marked as valid based on sensor self-checks and internal rationality judgments.

[0074] The first atmospheric data computer 201 and the second atmospheric data computer 202, based on the five-hole pressure data from their respective five-hole probes, use a pre-calibrated aerodynamic model or lookup table to calculate high-precision static pressure. Dynamic pressure Angle of attack and sideslip angle .

[0075] The third atmospheric data computer 203 calculates the static pressure based on the static pressure and angle sensor 1031 data from the total static pressure pitot tube 103. Dynamic pressure Angle of attack and sideslip angle .

[0076] All three computers utilize total temperature and static pressure Information such as vacuum velocity is used to calculate the vacuum velocity using the following formula. : ; in, It is the total temperature and coefficient of recovery Wait for the calculated static temperature, This is the specific heat ratio of air.

[0077] Among them, static temperature From total temperature coefficient of recovery and Mach number According to the formula Iteratively derived, Specific heat ratio of air, Mach number Based on the ratio of dynamic pressure to static pressure Preliminary estimates were obtained.

[0078] S4: The atmospheric data voting and management module inside the flight control computer filters parameters based on the enable information, performs pairwise consistency checks and voting fusion on the triple redundancy data, and outputs the final voting results and parameter validity status.

[0079] This step is performed by the atmospheric data voting and management module inside the flight control computer 300, and is a key step in achieving high-reliability data output in this solution.

[0080] S401: The atmospheric data voting and management module first reads the current... Based on the parameter enable information determined in step S2, the module identifies a list of parameters that are enabled (i.e., in a valid or degraded state) in the current operating mode. This module only performs subsequent voting and fusion operations on parameters within the list. Any parameter in a failed state will be directly excluded from the main control link.

[0081] S402: For each enabled parameter (such as barometric altitude in rotor mode) or vacuum speed in cruise mode The module will receive three independent measurements from three atmospheric data computers. .

[0082] For example, the voting logic employs a multi-level strategy: First layer: Pairwise threshold consistency check. Calculate the absolute value of the difference between each pair of the three values: , , If all differences are less than the preset threshold... If the three redundancy data are consistent, the system is considered healthy. If only one set of differences is less than... If so, the system will identify it as a 1-to-1 fault.

[0083] Second layer: Voting algorithm selection.

[0084] When the redundancy is consistent: the median value selection method can be used, that is, sort the three values ​​and take the median value. As a result of the vote, this method can effectively filter out burrs in single-redundancy systems.

[0085] When two redundancies are consistent, but the third redundancy drifts or fails: the system automatically isolates the faulty redundancy and uses the average value method or selects one of the consistent redundancy data as the master data. The formula for calculating the average value method is as follows: ,in and These are two values ​​that pass the consistency check.

[0086] When all three redundancies are inconsistent: trigger the highest-level alarm, and the system can use a weighted fusion algorithm. Weights Based on the historical quality scores of each channel, sensor self-test information, and mode status, the weighted fusion formula is dynamically adjusted as follows: Among them, weight The initial values ​​are all set to 1. During system operation, if a certain redundancy (such as the first...) is... The computer (in Taiwan) was marked as downgraded, and its corresponding weight was determined by... Exponential decay is applied; if the redundancy passes the consistency check three times consecutively and the state is restored to validity, its weight is adjusted accordingly. The system is gradually restored, and each weight change is recorded in the fault log in non-volatile memory for traceability during ground maintenance.

[0087] At this point, the fused parameters It will be marked as downgraded.

[0088] S403: For each voted parameter, this module integrates the status words of each input redundancy, the consistency check results, and the communication link status to generate the final validity state of the parameter. When the signal source of a parameter is in transition mode, some redundancy is failed, or the consistency check shows that all three redundancies are inconsistent, the flight control computer (300) marks the main state of the parameter as degraded. Data in a degraded state can still be used, but the flight control law will correspondingly reduce its influence weight on the control loop, or switch to a more conservative control gain. When all redundancies are marked as failed or communication is completely interrupted, the parameter is marked as failed, the flight control system will completely abandon the use of the parameter, and reconstruct the flight state based on other valid parameters (such as attitude and acceleration provided by inertial navigation).

[0089] S5: The flight control computer sends the atmospheric parameters and status words after the vote to the display control system. At the same time, it packages and sends the three sets of raw data, status words and pairwise differences before the vote for comprehensive display and fault diagnosis.

[0090] This step enables a transparent presentation of data, information, and decision-making processes.

[0091] The flight control computer (300) will generate the post-voting atmospheric parameters (such as...) in step S4. Together with its final validity status word, it is sent to the display control system 400 via the data bus.

[0092] Crucially, to improve the system's observability and ease of maintenance, the flight control computer 300 simultaneously transmits the three sets of raw atmospheric parameters received during the S3 step, prior to the voting. Their respective validity status words and the real-time differences between each pair. They will be packaged and sent together.

[0093] Those skilled in the art should understand that the technical solutions disclosed in this invention allow for various modifications and equivalent substitutions to adapt to different eVTOL platforms and requirements.

[0094] Here are some examples of non-exhaustive enumeration: (1) In some fly-by-wire flight control systems, the motor tilt angle It may not be directly used as a communication variable. In this case, the mode criterion in step S1 can be equivalently replaced by the motor's operating status word.

[0095] For example, status word 0x01 represents vertical takeoff and landing (VTOL), 0x02 represents transitional state, and 0x03 represents cruise state. The flight control computer 300 directly parses this status word and uses it for mode determination in step S2. In this case, the decision logic in S2 can be simplified to a direct conversion of discrete status words, similarly applying hold-up time. This is to prevent interference from instantaneous status word transitions.

[0096] (2) In order to manage the risks of the transition phase more precisely, the transition model can be further divided into the pre-transition phase and the post-transition phase.

[0097] In the initial transition phase, corresponding to the motor tilt angle Just from In the initial stage of reduction, the dynamic pressure is still weak, and the system completely suppresses airspeed and angle parameters.

[0098] In the later stage of the transition, corresponding to near With the flight speed established, the dynamic pressure significantly increased and the flow field tending to stabilize, the system can first reduce the output vacuum speed and make an effective judgment on the angle of attack using boundary protection.

[0099] This refinement can be achieved by adding an intermediate threshold in S201. This allows for the creation of four working modes, further optimizing the balance between parameter availability and security.

[0100] (3) In step S402, the weights of the weighted fusion More complex adaptive mechanisms can be employed, where weights depend not only on historical quality but also on real-time dynamic pressure (PMP). This is related to the fact that the five-hole probe is more sensitive to angle calculation under low dynamic pressure, while the total static pressure measurement of the pneumatic tube is more robust under high dynamic pressure. The weights of the first / second redundancy and the third redundancy can be adjusted in real time according to the magnitude of the dynamic pressure.

[0101] For example, in the low-speed range of cruise mode, the first and second redundancies are given higher weights; in the high-speed range, the third redundancy or the average of the three is given higher weights. This adaptive weighting can further tap the performance potential of heterogeneous redundancy architecture.

[0102] In summary, this invention, through a system integration design concept, uses the aircraft's own physical state (motor tilt angle) as a starting point to drive the atmospheric data system to adaptively output data downwards, and provides a data stream with complete state information upwards to the flight control and display systems. This not only significantly reduces the control risks caused by atmospheric data misleading during the full envelope operation of eVTOL aircraft, but also greatly improves the overall safety, monitorability, and mission completion capability of the system.

Claims

1. A multi-mode atmospheric data system for electric vertical takeoff and landing aircraft, characterized in that, include: The triple-redundant atmospheric data system includes a first atmospheric data computer, a second atmospheric data computer, and a third atmospheric data computer. Each atmospheric data computer is connected to a corresponding sensor to receive the mode status word and execute the differential calculation strategy according to the current flight phase, and output the corresponding set of atmospheric parameters and its validity status word. The flight control computer communicates with each atmospheric data computer to generate and send mode criteria. Based on the mode criteria, it determines the current flight phase through hysteresis threshold and hold-up time conditions and generates mode status words and parameter enable information. Based on the parameter enable information, it performs consistency checks and voting fusion on the triple redundancy measurements from the three atmospheric data computers to generate the voted atmospheric parameters and their final validity status. The display control system is communicatively connected to the flight control computer and is used to receive and display the atmospheric parameters after voting and their final validity status. It also receives and displays the original atmospheric parameters output by each atmospheric data computer, the validity status words corresponding to the original atmospheric parameters, and the parameter differences between pairs of redundancies.

2. A method for operating a multi-mode atmospheric data system for an electric vertical takeoff and landing (EVTOL) aircraft, implemented based on the multi-mode atmospheric data system for an EVTOL aircraft as described in claim 1, characterized in that... include: The flight control computer generates motor control commands based on the flight plan and the real-time status of the aircraft, extracts the motor tilt angle or motor operating status from the motor control commands as mode criteria, and sends the mode criteria to the first atmospheric data computer, the second atmospheric data computer and the third atmospheric data computer; The flight control computer determines the mode based on the mode criteria, using a preset hysteresis threshold and hold-up time condition, generates the mode status word and parameter enable information corresponding to the current flight phase, and sends the mode status word and parameter enable information to each atmospheric data computer. Each atmospheric data computer executes a differential resolution strategy that matches the current flight phase based on the received mode status word, outputs the corresponding set of atmospheric parameters, and adds a validity status word to each output atmospheric parameter. The flight control computer, based on the parameter enable information, filters the atmospheric parameters enabled in the current flight phase, performs consistency checks and voting fusion on the triple redundancy measurement values ​​from the three atmospheric data computers, and generates the voted atmospheric parameters and their corresponding final validity status. The flight control computer sends the voted atmospheric parameters to the display control system, and at the same time sends the original atmospheric parameters output by each atmospheric data computer, the validity status words corresponding to the original atmospheric parameters, and the parameter differences between each pair of redundancies to the display control system for comprehensive display and fault diagnosis.

3. The operating method of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 2, characterized in that, The pattern determination specifically includes: The flight control computer pre-sets a first threshold and a second threshold, wherein the first threshold is greater than the second threshold, and sets a holding time. When the duration for which the motor tilt angle is less than or equal to the first threshold reaches the holding time, the current mode switches from rotor mode to transition mode; When the duration for which the motor tilt angle is greater than or equal to the first threshold reaches the holding time, the current mode is switched from the transition mode to the rotor mode; When the duration for which the motor tilt angle is less than or equal to the second threshold reaches the holding time, the current mode switches from the transition mode to the cruise mode; When the duration for which the motor tilt angle is greater than or equal to the second threshold reaches the holding time, the current mode switches from the cruise mode to the transition mode; When the motor tilt angle is between the second threshold and the first threshold, the current mode remains the transition mode.

4. The operating method of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 2, characterized in that, The differential resolution strategy includes: In the rotor mode, each atmospheric data computer outputs static pressure, total temperature, and pressure altitude, and marks the validity status words of vacuum speed, angle of attack, and sideslip angle as failed; In the transition mode, each air data computer outputs at least static pressure, total temperature, and pressure altitude. When the dynamic pressure is greater than a preset dynamic pressure threshold and the airspeed difference between two air data computers is less than a preset consistency threshold, the validity status word of the airspeed parameter is marked as valid; otherwise, it is marked as downgraded or invalid. In the cruise mode, each atmospheric data computer outputs static pressure, dynamic pressure, total temperature, barometric altitude, vacuum velocity, angle of attack, and sideslip angle, and marks the validity status of all parameters as valid.

5. The operating method of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 2, characterized in that, The integration of consistency checks and voting specifically includes: The flight control computer calculates the pairwise differences between three measured values ​​of the same parameter output by the three air data computers and compares each difference with a preset threshold. When all differences are less than the threshold, the median of the three measurements is taken as the voting result. When only one set of differences is less than the threshold, the third redundancy is isolated, and the average of the two measurements that pass the consistency check is taken as the voting result. When all three differences are not less than the threshold, a weighted fusion algorithm is used to calculate the voting result, and the voting result is marked as downgraded.

6. The operating method of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 5, characterized in that, In the weighted fusion algorithm, the initial weight values ​​of each redundancy are all set to be equal; When a certain redundancy is marked as degraded, the weight of that redundancy decays exponentially. When a certain redundancy passes the consistency check consecutively and the state is restored to validity, the weight of that redundancy is gradually restored to its initial value; Each weight change is recorded in non-volatile memory.

7. The operating method of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 2, characterized in that, After generating the atmospheric parameters and their corresponding final validity status following the voting, the process also includes: degradation and failure management, as detailed below: When the signal source of an atmospheric parameter is in transition mode, partially redundant, or the triple redundancy measurements are inconsistent, the flight control computer marks the final validity state of the parameter as downgraded and reduces the influence weight of the parameter in the flight control law. When all redundancies are marked as invalid or communication is completely interrupted, the flight control computer marks the final validity state of the parameter as invalid and reconstructs the flight state based on the inertial navigation parameters.

8. The operating method of a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 2, characterized in that, When the mode criterion is abnormal, the communication between the flight control computer and the air data computer is interrupted, or the quality index of the air parameters is lower than the preset threshold, the flight control computer will switch the corresponding parameters to a degraded or failed state, and maintain the basic atmospheric parameter output of static pressure, total temperature and pressure altitude.

9. The method for operating a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 2, characterized in that, The display control system displays the atmospheric parameters after the vote and their final validity status on the main flight display page, and displays the original atmospheric parameters output by the three atmospheric data computers, the validity status words corresponding to each original atmospheric parameter, and the parameter differences between each pair of redundancies on the system status display page.

10. The method for operating a multi-mode atmospheric data system for an electric vertical takeoff and landing aircraft according to claim 2, characterized in that, While sending the mode criteria to each atmospheric data computer, the flight control computer starts a communication monitoring timer. If no response confirmation signal is received from any of the air data computers within multiple consecutive transmission cycles, the communication link is determined to be abnormal, and the flight control computer immediately sends the mode status word to the backup enable port of each air data computer via the backup discrete signal line.

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