Patent Description:
Generally, an amount of power required by various VTOL aircraft is reduced when hovering in a headwind condition. The power reduction may be affected by various factors including wind line. Inability to determine wind line (e.g., wind magnitude and direction) can impair aircraft landing attempts. <CIT> discloses a method for estimating airspeed of an aircraft which includes receiving values indicative of operating conditions of the aircraft along an axis; estimating a tip path plane (TPP) angle along the axis from at least one of the operating conditions to create an estimated TPP angle; and determining an estimated airspeed as a function of the estimated TPP angle, the determining including referencing a look-up table that indexes the estimated TPP angle with the airspeed. <CIT> discloses a method and apparatus for estimating an airspeed of a rotorcraft by analyzing its rotor. The method makes it possible to determine said airspeed of the rotorcraft in a frame of reference united with the tip-path plane by solving a model of the rotor that puts a pitch angle of at least one blade relative to the tip-path plane into relation with the airspeed of the rotorcraft and with an auxiliary speed. The auxiliary speed may be an induced velocity of the air flowing through the rotor or else an axial airspeed at the upstream infinity of the rotorcraft. The present invention relates to a system and method according to the appended claims.

One aspect of the present disclosure relates to a wind estimation system for an aircraft. The wind estimation system includes, inter alia, a first sensor configured to sense a first position associated with an aircraft control component in a wind condition, a second sensor configured to sense a first configuration associated with a rotor system of the aircraft in the wind condition, at least one controller in communication with each of the first sensor or the second sensor. The at least one controller is configured to determine a tip-path-plane angle of the aircraft based on the first position and the first configuration, and determine at least one of a current wind speed or a current wind direction based on the tip-path-plane angle.

In various embodiments, the aircraft control component is selected from the list consisting of: a pitch control, a throttle control, an antitorque control, and a cyclic pitch control. In some embodiments, the wind estimation system further includes a third sensor configured to sense a global position of the aircraft in the wind condition, and wherein determining the tip-path-plane angle of the aircraft is further based on the global position. In other embodiments, at least of the second sensor or the third sensor is a spatial sensor. In yet other embodiments, one of the second sensor or the third sensor is a camera. In some embodiments, at least one of the second sensor or the third sensor respectively determine the first configuration or the global position using light detection and ranging (LIDAR).

In various embodiments, the first configuration comprises at least one of an angle of attack or a blade pitch. In some embodiments, determining the current wind speed includes comparing at least one of the first position or the first configuration respectively with a second position or a second configuration and estimating at least one of the current wind speed or current wind direction based on at least one of a reference wind speed or reference wind direction. The second position or second configuration is associated with at least one of the reference wind speed or the reference wind direction. In other embodiments, the wind estimation system further includes a database communicably coupled to the at least one controller, wherein at least one of the second position, second configuration, or reference wind speed are determined from the database. In yet other embodiments, the database includes a reference table.

Another aspect of the present disclosure relates to a method for calculating a wind speed. The method includes, inter alia, sensing, by a first sensor, a first position associated with an aircraft control component in a wind condition, sensing, by a second sensor, a first configuration associated with a rotor system of an aircraft in the wind condition, and sensing, by a third sensor, a global position of the aircraft. The method further includes determining, by a controller in communication with each of the first sensor, second sensor, and third sensor, a tip-path-plane angle of the aircraft based on the first position, the first configuration, and the global position, and determining, by the controller, a current wind speed based on the tip-path-plane angle.

In various embodiments, the method further includes sensing, by the first sensor, a reference position associated with the aircraft control component in the wind condition, sensing, by the second sensor, a reference configuration associated with the rotor system in the wind condition, sensing, by the third sensor, a reference position of the aircraft, and determining, by the controller, a reference tip-path-plane angle. In some embodiments, determining the current wind speed includes comparing at least one of the first position or the first configuration respectively with the reference position or the reference configuration, the reference position or reference configuration being associated with a reference wind speed, and estimating the current wind speed based on the reference wind speed.

In various embodiments, the method further includes storing, by a memory in communication with the controller, each of the reference position, the reference configuration, and the reference position in a database communicably coupled to the controller. In some embodiments, the database includes a look up table. In other embodiments, each of the reference wind speed is approximately <NUM> knots or less. In yet other embodiments, determining the tip-path-plane angle includes implementing a random sample consensus (RANSAC) algorithm.

Yet another aspect of the present disclosure relates to an aircraft. The aircraft includes a rotor system, at least one control component in communication with the rotor system, a first sensor configured to sense a first position associated with the at least one control component a wind condition, a second sensor configured to sense a first configuration associated with the rotor system in the wind condition, a global position determination system comprising a third sensor configured to sense a global position of the aircraft in the wind condition, and at least one controller in communication with each of the first sensor, the second sensor, and the third sensor. The at least one controller is configured to determine a tip-path-plane angle of the aircraft based on the first position, the first configuration, and the global position, and determine a current wind speed based on the tip-path-plane angle.

In various embodiments, the aircraft is at least one of a semiautonomous or autonomous vertical take-off and landing aircraft. In some embodiments, at least one of the second sensor or the third sensor is mounted to an airframe portion of the aircraft.

This summary is illustrative only and should not be regarded as limiting.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, as long as these fall within the scope of the appended claims.

Estimation of wind direction and magnitude can be performed in flight using a global position system (GPS) and/or an inertial measurement unit (IMU), and airspeed measurement equipment via pitot tubes. Pitot tubes measure pressure differences to calculate the airspeed of the aircraft. Although pitot tubes are sufficient in many circumstances (e.g., for fixed-wing aircraft), pitot tubes cannot provide accurate information in all circumstances-such as in use with helicopters, since helicopters may hover or operate at low airspeed regimes. The insufficiency of pitot tubes in determining wind speed and direction in the case of helicopters is because when helicopters move slowly or hover, the downwash from the rotor interferes with pitot tubes measurements. In hover and low speed operations, a helicopter pilot is then forced to use visual cues to estimate the direction and magnitude of the wind in their local operating environment using alternative methods (e.g., wind socks, flags, trees, etc.), which are not very accurate and are not always feasible to use. Knowing the direction and magnitude of wind is very important, and hovering into wind is a generally accepted safety practice. For example, in the event of an engine failure, a standard technique is to land the aircraft with minimal drift or yawing motion. This landing approach requires rapid but smooth application of aircraft controls, and performance of this maneuver is greatly improved when performed into the wind. Accordingly, for autonomous and semi-autonomous VTOL applications, knowledge of the accurate wind line (e.g., speed and direction) at low speed is important.

The approach in the present disclosure is directed to and intended for applications involving low airspeeds where aircraft pitot tubes (or similar mechanisms) cannot provide accurate information. However, even at higher airspeeds, the approach disclosed herein can be utilized as a secondary option (i.e., an alternative to pitot tubes or other similar mechanisms) to obtain wind magnitude and direction during flight.

Referring to <FIG> and <FIG>, schematic representations of perspective and front views of an aircraft <NUM> are shown. The aircraft <NUM> has a global position within a three dimensional space generally defined by a first axis <NUM>, a second axis <NUM>, and a third axis <NUM>, wherein each of the first, second, and third axes <NUM>, <NUM>, <NUM> are mutually perpendicular. The aircraft <NUM>, which is configured for vertical take-off and landing (VTOL), includes an airframe <NUM> having a main blade rotor system <NUM> and a tail rotor system <NUM> to facilitate flight in one or more wind conditions <NUM>. In various embodiments, the aircraft <NUM> may be autonomous or semiautonomous. The one or more wind conditions <NUM> ("wind line") includes or is defined by at least one of a wind magnitude or a wind direction.

As shown, the main rotor system <NUM> includes blades <NUM>, and the tail rotor system <NUM> includes blades <NUM>. In various embodiments, the main rotor system <NUM> includes a main rotor hub assembly <NUM>, which is configured to drive rotation of each of the blades <NUM>. The main rotor hub assembly may include a drive shaft, a main bearing, a plurality of pitch links and pitch bearings corresponding to each of the blades <NUM>. The aircraft <NUM> also includes one or more sensors <NUM> coupled to an exterior portion of the airframe <NUM>. As shown, the one or more sensors <NUM> may be mounted on opposing sides of the airframe <NUM>. In various embodiments, the one or more sensors <NUM> are adapted to sense a configuration of one or more structural components of the aircraft <NUM> during flight. In various embodiments, the one or more sensors <NUM> may be sensors configured for light detection and ranging (LIDAR). In some embodiments, the one or more sensors <NUM> may be or include a camera.

In various embodiments, the configuration of the one or more structural components may include, but are not limited to, a configuration of at least one of the main blade rotor system <NUM> or the tail rotor system <NUM>. The configuration may include or be characterized by at least one of an angle of attack, blade pitch (i.e., pitch of the blades <NUM>, <NUM>), or a rotor disk position (i.e., position of the rotor disk formed by at main rotor system <NUM> and/or tail rotor system <NUM>). Determination of the configuration of the main blade rotor system <NUM> and/or the tail rotor system <NUM> can be subsequently used to determine a tip-path-plane angle <NUM> of the main rotor system <NUM>.

The aircraft <NUM> also includes a wind estimation system <NUM>, a schematic representation of which is shown in <FIG>. The wind estimation system <NUM> is configured to determine the wind condition <NUM> acting on the aircraft <NUM>. As shown, the wind estimation system <NUM> includes an estimation unit <NUM>, which includes at least one controller <NUM> configured to receive input from the one or more sensors <NUM> ("aircraft structure sensors"), one or more sensors <NUM> ("aircraft control sensors"), a global positioning system <NUM> ("global positioning system <NUM>"), and a database <NUM>. The at least one controller <NUM> of the estimation unit <NUM> may be a non-transitory computer readable medium or processor, having computer-readable instructions stored thereon that, when executed, cause the at least one controller to carry out operations called for by the instructions. The at least one controller <NUM> of the estimation unit <NUM> may be provided with a power source, a memory, a communications interface, and a processor. In various embodiments, the at least one controller <NUM> of the estimation unit <NUM> may be a computing device. In other embodiments, the at least one controller <NUM> may be configured as part of a data cloud computing system configured to receive commands from a user control device and/or a remote computing device. In other embodiments, the at least one controller <NUM> of the estimation unit <NUM> may include fewer, additional and/or different components.

The one or more sensors <NUM> are configured to sense a position and/or setting of one or more aircraft controls disposed within the airframe <NUM> (e.g., within the cockpit). Such aircraft controls may include, but are not limited to a collective pitch control, a throttle control, an antitorque control, and a cyclic pitch control. For example, the one or more sensors <NUM> may be configured to sense a particular position or configuration of one or more pedals, levers, knobs, or other components associated with the aircraft controls. In various embodiments, the global positioning system may include one or more sensors configured to determine a spatial position of the aircraft <NUM> relative to a ground surface. In various embodiments, the one or more sensors <NUM> may be communicatively coupled to or included within a health and usage monitoring system (HUMS) contained within the aircraft <NUM>.

In various embodiments, the global position system <NUM> may include one or more sensors or receivers for detecting a position of the aircraft <NUM> during flight. The one or more sensors within the global position system <NUM> may include, but are not limited to, one or more Doppler velocity sensors, global positioning (GPS) receivers configured to receiver one or more signals from one or more navigation satellites, or any other sensors known in the art to facilitate position detection and determination in an aircraft. In various embodiments, the one or more sensors or receivers of the global position system <NUM> may be mounted to an exterior portion of the aircraft <NUM>, such as, for example, mounted to the airframe <NUM>.

During operation of the aircraft <NUM>, the estimation unit <NUM> is configured to receive outputs from each of the one or more sensors <NUM>, the one or more sensors <NUM>, and the global position system <NUM>. Outputs from the one or more sensors <NUM> include, but are not limited to, one or more configurations of one or more structural components of the aircraft, which are associated with at least one of the angle of attack, blade pitch (i.e., pitch of the blades <NUM>, <NUM>), or the rotor disk position (i.e., position of the rotor disk formed by at main rotor system <NUM> and/or tail rotor system <NUM>). Outputs from the one or more sensors <NUM> may further include the tip-path-plane angle <NUM> of the main rotor system <NUM>. Outputs from the one or more sensors <NUM> include, but are not limited to, a position and/or setting of one or more aircraft controls, which may be associated with at least one of the collective pitch control, the throttle control, the antitorque control, or the cyclic pitch control.

Upon receiving outputs from each of the one or more sensors <NUM>, <NUM>, the estimation unit <NUM> is configured to store said outputs within the database <NUM>, which is communicatively coupled to the estimation unit <NUM>. The database <NUM> is further configured to store global position information from the global position system <NUM>. In various embodiments, the database <NUM> may be located on the aircraft <NUM>, remotely located and wirelessly in communication, or as part of a data cloud computing system. In various embodiments, the database <NUM> may be a look-up or reference table.

Upon receipt of outputs from each of the one or more sensors, <NUM>, <NUM>, and from the global position system <NUM>, the estimation unit <NUM> determines the tip-path-plane angle <NUM>. Using the tip-path-plane angle <NUM>, along with the outputs from the one or more sensors <NUM>, the estimation unit <NUM> will determine the wind condition <NUM>, which may include the wind magnitude and direction. In various embodiments, the estimation unit <NUM> will subsequently store the determined wind condition <NUM> and the outputs associated with the wind condition <NUM> (i.e., the outputs from the one or more sensors <NUM>, <NUM> and/or the outputs from the global position system <NUM>) in the database <NUM>. The estimation unit <NUM> may then output the determined wind condition <NUM> to a user interface <NUM>, which is communicatively coupled to the estimation unit <NUM>. The estimation unit <NUM> may additionally output the information sensed by the one or more sensors <NUM>, <NUM> to the user interface <NUM>. In various embodiments, the user interface <NUM> may be a graphical interface. In some embodiments, the user interface <NUM> may include one or more components configured to be responsive to user input such as, but not limited to, one or more touch-sensitive regions, buttons, microphones, levers, or knobs. In various embodiments, the estimation unit <NUM> may be configured to determine the wind condition <NUM> responsive to an input from the user interface <NUM>.

According to the invention, determination of the wind condition <NUM> is based on rotor flapping dynamics and tip-path-plane <NUM> dynamics. In various implementations, determination of variables specific to the aircraft <NUM> facilitate determination of wind directions, and thus, the wind condition <NUM>. Equations <NUM> and <NUM>, as provided below, illustrate the mathematical relationship between wind condition <NUM> components and the rotor flapping and tip-path-plane <NUM> dynamics. <MAT> <MAT>.

As shown above in Equations <NUM> and <NUM>, in various implementations, the first derivatives of the lateral and longitudinal flapping angles, b́<NUM> and á<NUM>, respectively, are mathematically related to the lateral and longitudinal body angular rates, p and q, respectively, in addition to the lateral and longitudinal flapping pilot cyclic inputs (e.g., as determined by aircraft control sensors <NUM>), δlat and δlon, respectively. In various embodiments, the pilot cyclic inputs, δlat and δlon, may include a control position (e.g., a position of a joystick, actuator, lever, button, throttle or pedal position, etc.). The first derivatives of the flapping angles, b́<NUM> and á<NUM>, (and thus the flapping angles b<NUM> and a<NUM>) are also affected by the radius, R, of the main rotor blades <NUM>, the nominal rotational speed, Ω, of the main rotor <NUM>, an effective main rotor <NUM> time constant, τe, and gains from cyclic inputs to the main rotor <NUM> (i.e., Alat, Blat). The first derivatives of the flapping angles, b́<NUM> and á<NUM>, (and the flapping angles b<NUM> and a<NUM>) are also related to the aircraft <NUM> velocity components in three perpendicular directions, u, v, w, and wind velocity components in three perpendicular directions, uw,vw,ww, along with an advance ratio and normalized inflow, which relate the wind velocity components to the rotational speed, Ω, and the blade <NUM> radius, R. The advance ratio is provided below as Equation <NUM> and the normalized inflow is provided as Equation <NUM>. The flapping angles b<NUM> and a<NUM>, are thus determined (via the first derivatives b́<NUM> and á<NUM>) as a function of the wind velocities, uw,vw,ww, and various control inputs, including the pilot cycling inputs, δlat and δlon. <MAT> <MAT>.

In equations <NUM>-<NUM>, the aircraft <NUM> velocity components, u, v, and w, (i.e., ground speed) may be measured by the global positioning system <NUM>. The control inputs, δlat and δlon, may be measured by the aircraft control sensors <NUM>. As described above, the aircraft <NUM> includes one or more sensors <NUM> configured to determine the tip-path-plane angles <NUM>, which include the flapping angles, b<NUM> and a<NUM>, using, for example, a detection technology including but not limited to LIDAR. The wind velocity components, uw,vw,ww, are defined in three perpendicular directions with respect to the aircraft <NUM>. However, to determine the wind velocity components relative to an inertial frame of reference, which is necessary to determine the wind condition <NUM>, Equations <NUM>-<NUM> can be first rearranged to solve for the wind velocity components, uw,vw,ww, relative to the aircraft <NUM>. Then, the wind velocity components relative to the aircraft <NUM> can be subsequently converted to wind velocity relative to the inertial frame of reference using aircraft pitch and/or roll (i.e., as determined by at least one of the aircraft global position system <NUM> or an inertial navigation system) to determine the wind condition <NUM>. Thus, by determining the tip-path-plane angles <NUM> and the flapping angles, b<NUM> and a<NUM>, using, e.g., LIDAR (i.e., via the one or more sensors <NUM>), along with the control inputs, δlat and δlon, the wind velocity components can be calculated to determine the wind condition <NUM>.

<FIG> shows a method <NUM>, which is implemented to generate a look-up table to be used by the wind estimation system <NUM> in determining the wind condition <NUM>. In various embodiments, the aircraft <NUM> may be operated in a controlled environment (e.g., simulator) where control inputs, structural component configurations, and ground speed of the aircraft <NUM> can be measured and recorded, and where the wind condition <NUM> is known. In other embodiments, the aircraft <NUM> operation may be virtually simulated using one or more computer-simulated environments. Accordingly, each of the control inputs, component configurations (e.g., tip-path-plane angles <NUM>), and ground speed can be recorded at different, known wind conditions <NUM> to generate a look-up table, which can be saved in the database <NUM> and later used by the wind estimation unit <NUM> within the wind estimation system <NUM>.

In a first operation <NUM>, a position, setting, or configuration of one or more controls within the aircraft <NUM> is determined and recorded during a controlled simulation (e.g., a known wind condition). In various embodiments, the one or more controls may include at least one of a collective control, pitch control, a throttle control, an antitorque control, or a cyclic pitch control, which can then be used as the control inputs, δlat and δlon, in Equations <NUM> and <NUM>. In operation <NUM>, a configuration of one or more structural components of the aircraft <NUM> is determined and recorded, where the configuration of the one or more structural components are associated with at least one of the angle of attack, blade pitch, the rotor disk position, or the tip-path-plane angle <NUM>. The flapping angles, b<NUM> and a<NUM>, are recorded to determine the tip-path-plane angle <NUM>. Subsequently or concurrently, in an operation <NUM>, the velocity of the aircraft <NUM> (e.g., ground speed), u, v, and w, are determined and recorded. In a subsequent or concurrent operation <NUM>, the wind condition <NUM> is also determined and recorded. The wind condition <NUM> may include at least one of the wind magnitude or wind direction, and including the wind velocity components, uw,vw,ww. To determine the wind condition <NUM>, the wind velocity components may be converted from being defined relative to the aircraft <NUM> frame of reference to being defined relative to a global frame of reference. In various embodiments, each of the operations <NUM>-<NUM> may be carried out by the wind estimation system <NUM>, where each of the control inputs, component configurations, and aircraft <NUM> velocity are determined by the controller <NUM> (e.g., by the sensors <NUM>, <NUM>, <NUM>) and saved in the database <NUM>. In various embodiments, each of the control inputs, component configurations, aircraft <NUM> velocity, and/or wind condition <NUM> may be externally measured (e.g., by one or more sensors external to the aircraft <NUM>) and later saved to the database <NUM> in the lookup table, such as by communication with the controller <NUM> via the user interface <NUM>.

In various embodiments, the wind estimation unit <NUM> may be configured to determine the wind condition <NUM> from known control inputs, ground speed, and tip-path-plane angle <NUM> by solving for the wind velocity components, uw,vw,ww, (i.e., using Equations <NUM> and <NUM>), which may be stored in a lookup table (i.e., within the database <NUM>). Consequently, in subsequent iterations, the wind estimation unit <NUM> may determine the wind condition <NUM> by retrieving the stored wind velocity components (i.e., from the lookup table generated via the method <NUM> and stored in the database <NUM>).

<FIG> shows a method <NUM>, which is implemented by the wind estimation system <NUM> to determine an unknown wind condition <NUM> using a lookup table stored in the database <NUM>, where the lookup table is based on one or more previously determined and stored wind conditions (e.g., as determined from the method <NUM>). In an operation <NUM>, the wind estimation system <NUM> may sense (e.g., via the sensors <NUM>) a new control setting, which determine δlat and δlong. Alternatively, the control setting may be input or otherwise set using the user interface <NUM>. In a subsequent or concurrent operation <NUM>, the wind estimation system <NUM> determines the tip-path-plane angle <NUM> by sensing the flapping angles, a<NUM> and b<NUM>, of the rotor blades <NUM> using the sensors <NUM>. In various embodiments, the flapping angles, a<NUM> and b<NUM>, may be determined using LIDAR. In an operation <NUM>, the velocity of the aircraft <NUM> (e.g., ground speed), u, v, and w, may be measured by the global position system <NUM>.

In an operation <NUM>, upon sensing the new information (i.e., the control inputs, component configuration, and ground speed) from the one or more sensors <NUM>, <NUM> and global position system <NUM> in the operations <NUM>-<NUM>, the estimation unit <NUM> may compare the new information from the one or more sensors <NUM>, <NUM> and the global positon system <NUM> to the lookup table stored in the database <NUM>. Specifically, the controller <NUM> within the wind estimation unit <NUM> may compare the new information obtained in operations <NUM>-<NUM> to corresponding reference information within the lookup table. The reference information includes at least one stored wind condition <NUM> ("reference wind condition" or "prior wind condition"), which is determined through the method <NUM>, and is associated with a corresponding stored control position or control inputs ("reference position"), stored aircraft component configuration ("reference configuration"), and aircraft <NUM> velocity (e.g., ground speed). Finally, in an operation <NUM>, the estimation unit <NUM> may then determine or estimate a new wind condition <NUM> (including at least one of a wind direction or a wind speed) based on the comparison of the new information sensed by the one or more sensors <NUM>, <NUM> to the reference wind condition (and reference wind speed and/or reference wind direction), the reference position, and/or the reference configuration. In various embodiments, the new wind condition <NUM> may align or correspond with a reference wind condition. In other embodiments, the new wind condition <NUM> may be estimated based on one or more reference wind conditions. Upon determining the new wind condition <NUM>, the wind estimation system <NUM> may then output the new wind condition <NUM> via the user interface <NUM>.

In various embodiments, the database <NUM> may additionally or alternatively include stored wind conditions based on experimental data, flight simulations, and/or predetermined wind conditions preprogrammed by a user, which may be included in the lookup table. In some embodiments, the wind estimation system <NUM> may additionally or alternatively may include or be in communication with one or more neural networks, wherein the wind estimation system <NUM> is configured to determine the wind condition <NUM> using the one or more neural networks.

In various embodiments, the wind estimation unit <NUM> may be configured to use random sample consensus (RANSAC). Because various sensing mechanisms including LIDAR (i.e., to determine configurations of the aircraft <NUM> components, along with ground speed and position) generate many data points, the wind estimation unit <NUM> may receive the data points (i.e., at the controller <NUM>) and implement one or more plane fitting algorithms (e.g., a random sample consensus (RANSAC) that performs iteration to construct a model from a dataset containing outliers) to remove outliers.

Notwithstanding the embodiments described above in reference to <FIG>, various modifications and inclusions to those embodiments are contemplated and considered within the scope of the present disclosure, as long as these fall within the scope of the appended claims.

As utilized herein with respect to numerical ranges, the terms "approximately," "about," "substantially," and similar terms generally mean +/- <NUM>% of the disclosed values, unless specified otherwise. As utilized herein with respect to structural features (e.g., to describe shape, size, orientation, direction, relative position, etc.), the terms "approximately," "about," "substantially," and similar terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

The term "coupled" and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable. Such coupling may be mechanical, electrical, or fluidic.

The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

In some embodiments, particular processes and methods may be performed by circuitry that is specific to a given function. The memory (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory may be or include volatile memory or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. According to an exemplary embodiment, the memory is communicably connected to the processor via a processing circuit and includes computer code for executing (e.g., by the processing circuit or the processor) the one or more processes described herein.

Claim 1:
A wind estimation system (<NUM>) for an aircraft (<NUM>), the system comprising:
a first sensor (<NUM>) configured to sense a first position associated with an aircraft control component in a wind condition;
a second sensor (<NUM>) configured to sense a first configuration associated with a rotor system (<NUM>) of the aircraft in the wind condition including sensing flapping angles (a<NUM>, b<NUM>) of rotor blades (<NUM>) of the aircraft; and
at least one controller (<NUM>, <NUM>) in communication with the first sensor (<NUM>) and the second sensor (<NUM>), the at least one controller (<NUM>) being configured to:
determine a tip-path-plane angle (<NUM>) of the aircraft based on the first position and the first configuration; and
determine at least one of a current wind speed or current wind direction associated with the wind condition based on the tip-path-plane angle (<NUM>).