Patent Publication Number: US-2020278701-A1

Title: Method and computer program for controlling tilt angle of main rotor on basis of vertical attitude control signal low-speed flight state, and vertical take-off and landing aircraft

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT Application No. PCT/KR2018/011531, filed Sep. 28, 2018, which claims priority to Korean Patent Application No. 10-2017-0177493, filed Dec. 21, 2017 and Korean Patent Application No. 10-2018-0020738, filed Feb. 21, 2018, the disclosures of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a method of controlling a tilt angle of a main rotor based on a vertical posture control signal during low-speed flight, a computer program therefor, and a vertical take-off/landing aircraft. 
     BACKGROUND 
     Commonly used speedometers for aircrafts are capable of accurately measuring speed only at high speeds above a certain critical speed (e.g., 60 km/h). To measure speeds therebelow, helicopters generally use GPS-based inertial speedometers, and a fixed-wing aircraft often does not have a separate inertial speedometer. 
     An inertial speedometer may measure speed at a high speed as well as a low speed such as hovering. However, because the inertial speedometer measures speed based on positions, when there is wind, an actual air speed cannot be measured, and thus, the inertial speedometer may not be used for determining flight characteristics. On the other hand, as mentioned above, although the minimum speed that may be measured by an air speed speedometer is limited as described above, it may be used to grasp flight characteristics, because it may directly measure the dynamic pressure that affects flight characteristics, such as stall speed. 
     A tilt-rotor or tilt-duct vertical take-off/landing unmanned aircraft that may change the direction of a main rotor that generates thrust according to the speed is designed to change the direction of the thrust by controlling the direction of the main rotor according to the air speed. 
     However, in a low-speed section near the stop speed, where it is difficult to measure the air speed, it is inevitable to use a GPS-based inertial speed for the above-mentioned reason, and a very large difference occurs between the actual air speed and an inertial speed depending on the wind strength. 
     Therefore, when the wind blows, the air speed changes, and thus, the main rotor of an aircraft needs to be properly tilted. However, since an inertial speed does not reflect the speed of the wind, the main rotor may not be tilted according to the inertial speed. Therefore, in an inertial speed-based system operating in a windy environment, a method of automatically controlling the tilt angle of a main rotor is needed. 
     SUMMARY 
     Provided is a vertical take-off/landing aircraft that may stably fly at a low speed by controlling tilting of a main rotor in conjunction with a vertical posture control signal, and more specifically, an instruction for changing a pitch posture angle in a direction of lowering the nose of the vertical take-off/landing aircraft. 
     More specifically, provided is a vertical take-off/landing aircraft that may stably hover in an environment in which strong wind blows or the strength of the wind changes over time. 
     Provided is to change the tilt angle of the main rotor actively compensated for according to changes of the air speed due to wind by automatically generating instructions for tilting a main rotor, based on a vertical posture control signal under a low-speed flight condition where it is difficult to directly measure a wind speed. 
     According to an aspect of the present disclosure, a vertical take-off/landing aircraft controlling a tilt angle of a main rotor based on a vertical posture control signal during low-speed flight includes at least one main rotor configured to change its tilt angle based on a tilt angle control signal generated by a flight controller and generate thrust of the vertical take-off/landing aircraft; an auxiliary rotor configured to change a pitch posture angle of the vertical take-off/landing aircraft based on a pitch posture angle control signal; and the flight controller configured to generate the tilt angle control signal and the pitch posture angle control signal based on an aircraft steering signal of the vertical take-off/landing aircraft. 
     When an aircraft steering signal including a vertical posture control signal for changing the pitch posture angle of the vertical take-off/landing aircraft by a first pitch posture angle is obtained, the flight controller may determine a tilt angle of the main rotor with reference to the first pitch posture angle and generates a tilt angle control signal for the main rotor based on the determined tilt angle. 
     The flight controller may generate the tilt angle control signal for the main rotor in correspondence to the vertical posture control signal for changing the pitch posture angle by the first pitch posture angle only when the speed of the vertical take-off/landing aircraft is less than or equal to a predetermined critical speed. 
     A heading direction of the vertical take-off/landing aircraft and a traveling direction of head wind against the vertical take-off/landing aircraft may be opposite to each other. The greater the strength of the head wind is, the larger the pitch posture angle, which changes in the direction in which the nose of the vertical take-off/landing aircraft descends, may become. 
     The flight controller may generate a control signal for tilting the main rotor, such that a rotation axis of the main rotor becomes more parallel to the ground as the pitch posture angle changing in the direction in which the nose of the vertical take-off/landing aircraft descends increases. 
     The pitch posture angle changing in the direction in which the nose of the vertical take-off/landing aircraft descends and the tilt angle of the main rotor may be in a linear relationship or a non-linear relationship. 
     The flight controller may generate a correcting signal comprising a tilt angle correcting angle for the main rotor based on pre-set aircraft speed-main rotor tilt angle mapping data. 
     When an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft in a direction of lowering the nose of the vertical take-off/landing aircraft by a first pitch posture angle is obtained, the flight controller may update the aircraft speed-main rotor tilt angle mapping data, such that the tilt angle correcting angle, which is corrected according to a tilt angle correcting signal, decreases based on a current speed of the vertical take-off/landing aircraft and a current tilt angle of the main rotor. 
     The flight controller may control the tilt angle of the main rotor based on the tilt angle of the main rotor, which is determined with reference to the first pitch posture angle, and the correcting angle. 
     The pitch posture angle control signal may include at least one of a signal for controlling the number of rotations of the auxiliary rotor and a signal for controlling the collective pitch angle of the auxiliary rotor. 
     The pitch posture angle control signal may include a signal for controlling the cyclic pitch angle of the main rotor. 
     The pitch posture angle control signal may include a signal for controlling an angle of a vane control plane of the main rotor. 
     According to another aspect of the present disclosure, a method of controlling a vertical take-off/landing aircraft controlling a tilt angle of a main rotor, based on a vertical posture control signal during low-speed flight, includes obtaining an aircraft steering signal including a vertical posture control signal for changing the pitch posture angle of the vertical take-off/landing aircraft by a first pitch posture angle; generating a pitch posture angle control signal for changing a pitch posture angle of the vertical take-off/landing aircraft based on the vertical posture control signal; and determining a tilt angle of the main rotor with reference to the first pitch posture angle and generating a tilt angle control signal for the main rotor based on the determined tilt angle. 
     The tilt angle control signal for the main rotor may be generated in correspondence to the vertical posture control signal for changing the pitch posture angle by the first pitch posture angle only when the speed of the vertical take-off/landing aircraft is less than or equal to a predetermined critical speed. 
     A heading direction of the vertical take-off/landing aircraft and a traveling direction of head wind against the vertical take-off/landing aircraft may be opposite to each other. The greater the strength of the head wind is, the larger the pitch posture angle, which changes in the direction in which the nose of the vertical take-off/landing aircraft descends, may become. 
     A control signal for tilting the main rotor may be generated, such that a rotation axis of the main rotor becomes more parallel to the ground as the pitch posture angle changing in the direction in which the nose of the vertical take-off/landing aircraft descends increases. 
     The pitch posture angle changing in the direction in which the nose of the vertical take-off/landing aircraft descends and the tilt angle of the main rotor may be in a linear relationship or a non-linear relationship. 
     The method may further include, after the generating of the tilt angle control signal of the main rotor, generating a correcting signal including a tilt angle correcting angle for the main rotor based on pre-set aircraft speed-main rotor tilt angle mapping data. 
     The generating of the correcting signal may include, when an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft in a direction of lowering the nose of the vertical take-off/landing aircraft by a first pitch posture angle is obtained, updating the pre-set aircraft speed-main rotor tilt angle mapping data, such that the tilt angle correcting angle, which is corrected according to a tilt angle correcting signal, decreases based on a current speed of the vertical take-off/landing aircraft and a current tilt angle of the main rotor. 
     In the generating of the correcting signal, the tilt angle of the main rotor may be controlled based on the tilt angle of the main rotor, which is determined with reference to the first pitch posture angle, and the correcting angle. 
     The pitch posture angle control signal may include at least one of a signal for controlling the number of rotations of the auxiliary rotor  300  and a signal for controlling the collective pitch angle of the auxiliary rotor. 
     The pitch posture angle control signal may include a signal for controlling the cyclic pitch angle of the main rotor. 
     The pitch posture angle control signal may include a signal for controlling an angle of a vane control plane of the main rotor. 
     According to embodiments of the present disclosure, a vertical take-off/landing aircraft may stably hover and fly at a low speed by controlling tilting of a main rotor in conjunction with a vertical posture control signal, and more specifically, an instruction for changing a pitch posture angle in a direction of lowering the nose of the vertical take-off/landing aircraft. 
     Also, the vertical take-off/landing aircraft may stably hover in an environment in which strong wind blows or the strength of the wind changes over time. 
     Accordingly, by automatically generating an instruction for tilting a main rotor, based on a vertical posture control signal under a low-speed flight condition where it is difficult to directly measure a wind speed, the tilt angle of the main rotor may be actively compensated for according to changes of the air speed due to wind. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view of a vertical take-off/landing aircraft according to an embodiment of the present disclosure. 
         FIG. 2  is a schematic diagram showing a configuration of a flight controller according to an embodiment of the present disclosure. 
         FIG. 3  is a diagram showing an example of an environment in which a vertical take-off/landing aircraft hovers according to an embodiment of the present disclosure. 
         FIGS. 4A and 4B  are diagrams for describing a method, performed by a flight controller, of tilting a main rotor in various environments, according to an embodiment of the present disclosure. 
         FIG. 5A  is a diagram showing an example of aircraft speed-main rotor tilt angle mapping data according to an embodiment of the present disclosure. 
         FIG. 5B  is a diagram showing an example of aircraft speed-main rotor tilt angle mapping data updated by a flight controller according to an embodiment of the present disclosure. 
         FIG. 6  is a diagram for describing a method of controlling a vertical take-off/landing aircraft, wherein the method is performed by a flight controller, according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     According to an aspect of the present disclosure, a vertical take-off/landing aircraft controlling a tilt angle of a main rotor, based on a vertical posture control signal during low-speed flight, includes at least one main rotor configured to change its tilt angle based on a tilt angle control signal generated by a flight controller and generate thrust of the vertical take-off/landing aircraft; an auxiliary rotor configured to change a pitch posture angle of the vertical take-off/landing aircraft based on a pitch posture angle control signal; and the flight controller configured to generate the tilt angle control signal and the pitch posture angle control signal based on an aircraft steering signal of the vertical take-off/landing aircraft, wherein, when an aircraft steering signal including a vertical posture control signal for changing the pitch posture angle of the vertical take-off/landing aircraft by a first pitch posture angle is obtained, the flight controller may determine a tilt angle of the main rotor with reference to the first pitch posture angle and generate a tilt angle control signal for the main rotor based on the determined tilt angle. 
     The present disclosure may include various embodiments and modifications, and embodiments thereof will be illustrated in the drawings and will be described herein in detail. The effects and features of the present disclosure and the accompanying methods thereof will become apparent from the following description of the embodiments, taken in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments described below, and may be embodied in various modes. 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and a repeated explanation thereof will not be given. 
     It will be understood that although the terms “first”, “second”, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These elements are only used to distinguish one element from another. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components. Sizes of elements in the drawings may be exaggerated for convenience of explanation. In other words, since sizes and thicknesses of components in the drawings are arbitrarily illustrated for convenience of explanation, the following embodiments are not limited thereto. 
       FIG. 1  is a schematic view of a vertical take-off/landing aircraft  10  according to an embodiment of the present disclosure. 
     In the present disclosure, the ‘vertical take-off/landing aircraft’  10  may refer to various types of aircrafts capable of taking off and/or landing in a direction perpendicular to the ground. For example, the vertical take-off/landing aircraft  10  may be an aircraft similar to an aircraft shown in  FIG. 1 , which includes two main rotors  200 R and  200 L, an auxiliary rotor  300 , and a flight controller  100  controlling them. 
     A tilt angle of the main rotors  200 R and  200 L according to an embodiment of the present disclosure may be changed based on a tilt angle control signal generated by the flight controller  100 . At this time, the tilt angle of the main rotors  200 R and  200 L may be defined in a direction parallel to a rotation axis vector  410  of the main rotors  200 R and  200 L. 
     For example, in  FIG. 1 , rotation planes of the main rotors  200 R and  200 L may be parallel to an X′-Y′ plane. Therefore, the rotation axis vector  410  may be in a +Z′ direction, and thus, the tilt angle of the main rotors  200 R and  200 L may correspond to 90 degrees. 
     Moreover, when the vertical take-off/landing aircraft  10  is flying at a high speed, the rotation planes of the main rotors  200 R and  200 L may be parallel to a Y′-Z ‘plane. Therefore, the rotation axis vector  410  may be in a +X’ direction, and thus, the tilt angle of the main rotors  200 R and  200 L may correspond to 0 degrees. 
     At this time, the X′, Y′, and Z′ coordinate system is a relative coordinate system and may be a coordinate system based on the vertical take-off/landing aircraft  10 . Defining the tilt angle of the main rotors  200 R and  200 L based on the rotation axis vector  410  as described above is merely an example, and the technical spirit of the present disclosure is not limited thereto. 
     The main rotors  200 R and  200 L according to an embodiment of the present disclosure may generate thrust of the vertical take-off/landing aircraft  10  in directions of the tilt angle according to a tilt angle control signal generated by the flight controller  100 . At this time, the ‘thrust’ refers to a force that pushes the vertical take-off/landing aircraft  10  in a direction in which the vertical take-off/landing aircraft  10  moves and may refer to a propulsion force generated by rotation of the main rotors  200 R and  200 L. 
     The main rotors  200 R and  200 L according to an embodiment of the present disclosure may include at least one of a cyclic pitch angle adjuster (not shown) and a vane control plane angle adjuster (not shown) instead of or together with the auxiliary rotor  300  described below. The cyclic pitch angle adjuster (not shown) and the vane control plane angle adjuster (not shown) may operate based on a pitch posture angle control signal described below. Detailed descriptions thereof will be given below. 
     The number of main rotors  200 R and  200 L may be one or more depending on the type of the vertical take-off/landing aircraft  10 . However, for convenience of explanation, descriptions will be given below under an assumption that there are two main rotors  200 R and  200 L as shown in  FIG. 1 . 
     The auxiliary rotor  300  according to an embodiment of the present disclosure may change a pitch posture angle of the vertical take-off/landing aircraft  10  based on a vertical posture control signal. 
     In the present disclosure, the ‘pitch posture angle of the vertical take-off/landing aircraft  10 ’ may refer to a degree to which the vertical take-off/landing aircraft  10  is inclined with respect to the ground. For example, when the pitch posture angle is 0 degrees, it may indicate a state in which the vertical take-off/landing aircraft  10  is parallel to the ground. Also, when the pitch posture angle is 10 degrees in a direction in which the nose of the vertical take-off/landing aircraft  10  descends, it may indicate that a front portion of the vertical take-off/landing aircraft  10  is lower than a rear portion. In the present disclosure, the ‘nose’ may refer to the front portion of an aircraft. 
     Moreover, when the auxiliary rotor  300  rotates rapidly, thrust generated by the auxiliary rotor  300  increases, and thus, the pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  descends may increase. 
     Also, when the auxiliary rotor  300  rotates relatively slow, thrust generated by the auxiliary rotor  300  decreases, and thus, the pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  descends may decrease. 
     Moreover, the auxiliary rotor  300  according to an embodiment of the present disclosure may further include a collective pitch angle adjuster (not shown) for adjusting a collective pitch angle of the auxiliary rotor  300 . The collective pitch angle adjuster (not shown) may adjust the collective pitch angle of the auxiliary rotor  300  according to the pitch posture angle control signal. When the collective pitch angle of the auxiliary rotor  300  increases, thrust generated by the auxiliary rotor  300  increases, and thus, the pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  descends may increase. 
     Also, when the collective pitch angle of the auxiliary rotor  300  relatively decreases, thrust generated by the auxiliary rotor  300  decreases, and thus, the pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  descends may decrease. 
     Moreover, the vertical take-off/landing aircraft  10  according to another embodiment of the present disclosure may include at least one of the cyclic pitch angle adjuster (not shown) of the main rotors  200 R and  200 L and the vane control plane angle adjuster (not shown) of the main rotors  200 R and  200 L instead of or together with the auxiliary rotor  300 . 
     The cyclic pitch angle adjuster (not shown) and the vane control plane angle adjuster (not shown) may adjust the pitch posture angle of the vertical take-off/landing aircraft  10  based on the pitch posture angle control signal instead of or together with the auxiliary rotor  300 . 
     However, for convenience of explanation, descriptions are given below under an assumption that the pitch posture angle of the vertical take-off/landing aircraft  10  is adjusted by the auxiliary rotor  300 . 
     The flight controller  100  according to an embodiment of the present disclosure may perform various operations for the flight of the vertical take-off/landing aircraft  10 . For example, the flight controller  100  may control the vertical take-off/landing aircraft  10  to fly according to a flight schedule by comparing a current position of the vertical take-off/landing aircraft  10  with a pre-set flight schedule. Also, the flight controller  100  may receive a steering signal of the vertical take-off/landing aircraft  10  from a user and control the vertical take-off/landing aircraft  10  based on the steering signal. Also, the flight controller  100  may control the main rotors  200 R and  200 L and the auxiliary rotor  300  described above in various situations. 
     Also, the flight controller  100  according to an embodiment of the present disclosure may control the vertical take-off/landing aircraft  10 , such that a heading direction of the vertical take-off/landing aircraft  10  is opposite to a traveling direction of head wind  500  against the vertical take-off/landing aircraft  10 . 
     However, for convenience of explanation, descriptions given below will focus on the technical configuration that the vertical take-off/landing aircraft  10  controls the main rotors  200 R and  200 L and/or the auxiliary rotor  300  during a low-speed flight. 
     Moreover, in the present disclosure, the ‘low speed flight’ may include both a case of hovering for take-off and/or landing and a case of being suspended in the air or moving at a low speed for a predetermined purpose. 
       FIG. 2  is a schematic diagram showing a configuration of a flight controller  100  according to an embodiment of the present disclosure. 
     The flight controller  100  according to an embodiment of the present disclosure may include a memory  110 , a processor  120 , a communication module  130 , and an input/output interface  140 , as shown in  FIG. 2 . 
     The memory  110  is a computer-readable recording medium and may include random access memory (RAM), read only memory (ROM), and a permanent mass storage device like a disk drive. Also, an operating system and at least one program code may be stored in the memory  110 . 
     The processor  120  may be configured to process instructions of a computer program by performing basic arithmetic, logic, and input/output operations. Instructions may be provided to the processor  120  by the memory  110  or the communication module  130 . For example, the processor  120  may be configured to execute a received instruction according to program code stored in a recording device like the memory  110 . 
     The communication module  130  may provide a function for communicating with an external device, such as a user terminal (not shown). For example, the communication module  130  may receive a signal for controlling the vertical take-off/landing aircraft  10  from a user terminal (not shown) and transmit the signal to the processor  120 . 
     The input/output interface  140  may be a unit for interfacing with an input/output device. At this time, an input device may include various sensors for determining the flight status of the vertical take-off/landing aircraft  10 , for example. For example, the input device may include a GPS sensor, an altimeter, and a geomagnetic sensor to determine a flight position of the vertical take-off/landing aircraft  10 . 
     Moreover, the flight controller  100  according to an embodiment of the present disclosure may be connected to the main rotors  200 L and  200 R and the auxiliary rotor  300  to control the tilt angle of the main rotors  200 L and  200 R based on a vertical posture control signal. The flight controller  100  may generate control signals for respectively controlling the main rotors  200 L and  200 R and the auxiliary rotor  300  and transmit the signals to them. 
     Descriptions given below with reference to  FIGS. 3 to 6  will focus on a method of generating control signals for respectively controlling the main rotors  200 L and  200 R and the auxiliary rotor  300  based on a vertical posture control signal during a hovering state. 
       FIG. 3  is a diagram showing an example of an environment in which the vertical take-off/landing aircraft  10  hovers according to an embodiment of the present disclosure. 
     Descriptions will be given below with reference to  FIGS. 4A to 6  under an assumption that the vertical take-off/landing aircraft  10  is hovering for landing as shown in  FIG. 3  and the heading direction (+X direction) of the vertical take-off/landing aircraft  10  is opposite to the traveling direction (−X direction) of the head wind  500  against the vertical take-off/landing aircraft  10 . In other words, descriptions will be given below under an assumption that, on an X-Y plane, there is a 180 degrees difference between the heading direction (+X direction) of the vertical take-off/landing aircraft  10  and the traveling direction (−X direction) of the head wind  500 . 
     Moreover, the X, Y, and Z coordinate system shown in  FIGS. 3 to 4B  is an absolute coordinate system based on the ground and may be different from the X′, Y′, and Z′ coordinate system based on the vertical take-off/landing aircraft  10  (described above with reference to  FIG. 1 ). 
     Under the above-stated assumptions, when an aircraft steering signal including a vertical posture control signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  by a first pitch posture angle is received, the flight controller  100  according to an embodiment of the present disclosure may determine the tilt angle of the main rotors  200 R and  200 L with reference to the first pitch posture angle and generate tilt angle control signals for the main rotors  200 R and  200 L based on the determined tilt angle. 
     In the present disclosure, the ‘aircraft steering signal’ refers to a signal for steering the vertical take-off/landing aircraft  10 . The aircraft steering signal may be received from a user terminal (not shown) or may be generated by the flight controller  100  according to a pre-set flight schedule. 
     Such an aircraft steering signal may include a signal for controlling the posture of an aircraft in horizontal directions and a signal for controlling the posture of the aircraft in vertical directions. 
     For example, a signal for controlling the posture in the horizontal directions may include a signal for controlling speed in the horizontal directions, a signal for controlling a horizontal rotation direction, etc. Moreover, a signal for controlling the posture in the vertical directions may include a signal for controlling speed in the vertical directions, a signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10 , etc. However, these are merely examples, and an aircraft steering signal may further include various signals in addition to the above-described signals or may not include at least some of the above-described signals. 
     Moreover, an aircraft steering signal may include a vertical posture control signal for increasing the pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  descends as the head wind  500  becomes stronger. 
     In other words, to maintain a hovering state, a user or the flight controller  100  may control the nose of the vertical take-off/landing aircraft  10  to be lowered, that is, control the front portion of the vertical take-off/landing aircraft  10  to be lower than the rear portion of the vertical take-off/landing aircraft  10 , as the head wind  500  becomes stronger. 
     The flight controller  100  according to an embodiment of the present disclosure may generate control signals for the main rotors  200 R and  200 L to tilt the main rotors  200 R and  200 L, such that the rotation axes of the main rotors  200 R and  200 L become more parallel to the ground as the pitch posture angle changing in the direction in which the nose of the vertical take-off/landing aircraft  10  descends increases. At this time, the controller  100  may generate a control signal for tilting the main rotor  200 , such that the pitch posture angle changing in the direction in which the nose of the vertical take-off/landing aircraft  10  descends and the tilt angle of the main rotors  200 R and  200 L satisfy a linear relationship or a nonlinear relationship. 
       FIGS. 4A and 4B  are diagrams for describing a method, performed by which the flight controller  100 , of tilting a main rotor  200 R in various environments, according to an embodiment of the present disclosure. 
     For convenience of explanation, descriptions will be given below under an assumption that the vertical take-off/landing aircraft  10  is hovering for landing as shown in  FIG. 3  and the heading direction of the vertical take-off/landing aircraft  10  is opposite to traveling directions of head winds  500 A and  500 B against the vertical take-off/landing aircraft  10 . Also, it is assumed that head wind  500 B of  FIG. 4B  is stronger than head wind  500 A of  FIG. 4A . 
     Referring to  FIG. 4A  under the above-described assumption, the flight controller  100  according to an embodiment of the present disclosure may control the auxiliary rotor  300 , such that the nose of the vertical take-off/landing aircraft  10  descends to maintain a hovering state against the head wind  500 A. 
     At this time, the flight controller  100  may increase the number of rotations of the auxiliary rotor  300  or the collective pitch angle to increase thrust  310 A generated by the auxiliary rotor  300 , and thus, the vertical take-off/landing aircraft  10  may have a pitch posture angle  420 A. 
     Moreover, as described above, the flight controller  100  according to an embodiment of the present disclosure may tilt the main rotor  200 R, such that the rotation axis of the main rotor  200 R becomes more parallel to the ground as the pitch posture angle  420 A changing in the direction in which the nose of the vertical take-off/landing aircraft  10  descends increases. 
     In other words, the flight controller  100  according to an embodiment of the present disclosure may control a tilt angle  411 A of the main rotor  200 R, such that a tilt angle  411 A decreases as the pitch posture angle  420 A increases. At this time, the tilt angle  411 A may refer to an angle defined in the direction of the rotation axis vector  410 A of the main rotor  200 R in the X′, Y′, and Z′ coordinate system as described above with reference to  FIG. 1 . 
     The main rotor  200 R may generate thrust  210 RA according to the changed tilt angle  411 A, such that the vertical take-off/landing aircraft  10  may stably hover. 
     On the other hand, referring to  FIG. 4B  in contrast to  FIG. 4A , the flight controller  100  according to an embodiment of the present disclosure may control the auxiliary rotor  300 , such that the nose of the vertical take-off/landing aircraft  10  is further lowered to maintain a hovering state against stronger head wind  500 B. 
     At this time, the flight controller  100  may increase the number of rotations of the auxiliary rotor  300  or the collective pitch angle to increase thrust  310 B generated by the auxiliary rotor  300  more than the thrust  310 A of  FIG. 4A , and thus, the vertical take-off/landing aircraft  10  may have a greater pitch posture angle  420 B. 
     Moreover, as described above, the flight controller  100  according to an embodiment of the present disclosure may tilt the main rotor  200 R, such that the rotation axis of the main rotor  200 R becomes more parallel to the ground as the pitch posture angle  420 B changing in the direction in which the nose of the vertical take-off/landing aircraft  10  descends increases. 
     In other words, the flight controller  100  according to an embodiment of the present disclosure may control a tilt angle  411 B of the main rotor  200 R, such that a tilt angle  411 B decreases as the pitch posture angle  420 B increases. At this time, the tilt angle  411 B may refer to an angle defined in the direction of the rotation axis vector  410 B of the main rotor  200 R in the X′, Y′, and Z′ coordinate system as described above with reference to  FIG. 1 . 
     The main rotor  200 R may generate thrust  210 RB according to the smaller tilt angle  411 B, such that the vertical take-off/landing aircraft  10  may stably hover against the strong head wind  500 B. 
     The flight controller  100  according to an embodiment of the present disclosure may perform the operations described with respect to  FIGS. 4A and 4B  only when the speed of the vertical take-off/landing aircraft  10  is less than or equal to a predetermined critical speed. In other words, when it is necessary for the vertical take-off/landing aircraft  10  to maintain a constant flight position for take-off or landing or to fly at a desired speed, the flight controller  100  according to an embodiment of the present disclosure may generate tilt angle control signals for main rotors in correspondence to a vertical posture control signal. 
     Also, the flight controller  100  according to an embodiment of the present disclosure may also perform the controls according to the descriptions given above with reference to  FIGS. 4A and 4B  with respect to a left main rotor  200 L. 
     The flight controller  100  according to an embodiment of the present disclosure may generate a correcting signal including a tilt angle correcting angle of the main rotor  200  based on pre-set aircraft speed-main rotor tilt angle mapping data. In the present disclosure, the ‘tilt angle correcting angle’ may refer to an angle for correcting a tilt angle calculated by the flight controller  100  through the above-described process. Also, the ‘aircraft speed-main rotor tilt angle mapping data’ may refer to data including a tilt angle of the main rotor  200  at each speed of an aircraft. 
       FIG. 5A  is a diagram showing an example of aircraft speed-main rotor tilt angle mapping data  610 A according to an embodiment of the present disclosure. 
     The flight controller  100  according to an embodiment of the present disclosure may check the speed of the vertical take-off/landing aircraft  10  and determine an appropriate tilt angle of the main rotors  200 R and  200 L at the corresponding speed with reference to the aircraft speed-main rotor tilt angle mapping data  610 A. For example, when the speed of the vertical take-off/landing aircraft  10  is 0 km/h, the flight controller  100  may determine 90 degrees as the appropriate tilt angle of the main rotors  200 R and  200 L. 
     Subsequently, the flight controller  100  according to an embodiment of the present disclosure may compare the tilt angle of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data  610 A with a current tilt angle of the main rotors  200 R and  200 L and calculate a difference angle therebetween. Also, the flight controller  100  may generate a correcting signal including a tilt angle correcting angle for the main rotors  200 R and  200 L based on the difference angle. 
     For example, as in the above-stated example, when the speed of the vertical take-off/landing aircraft  10  is 0 km/h, the flight controller  100  may determine 90 degrees as the appropriate tilt angle of the main rotors  200 R and  200 L. However, when the actual (current) tilt angle of the main rotors  200 R and  200 L is 80 degrees, the flight controller  100  may generate a correcting signal that utilizes 10 degrees, which is the difference between the both angles (the tilt angle according to the aircraft speed-main rotor tilt angle mapping data  610 A and the actual tilt angle, as a correcting angle. However, since tilt angles of the main rotors  200 R and  200 L according to the above-stated aircraft speed-main rotor tilt angle mapping data  610 A are mapping data corresponding to inertial speeds when there is no wind, the tilt angles of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data  610 A may not be appropriate when there is wind. 
     Therefore, when an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  by a second pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  is lowered is obtained, the flight controller  100  according to an embodiment of the present disclosure may update aircraft speed-main rotor tilt angle mapping data, such that a tilt angle correcting angle for the main rotors  200 R and  200 L, which is compensated for according to a correcting signal for the tilt angle, decreases based on a current speed of the vertical take-off/landing aircraft  10  and a current tilt angle of the main rotors  200 R and  200 L. 
       FIG. 5B  is a diagram showing an example of aircraft speed-main rotor tilt angle mapping data  610 B updated by the flight controller  100  according to an embodiment of the present disclosure. 
     As described above, the tilt angle of the main rotors  200 R and  200 L of the vertical take-off/landing aircraft  10  according to the aircraft speed-main rotor tilt angle mapping data  610 A corresponding to cases where there is no wind may, when there is wind, cause the vertical take-off/landing aircraft  10  to move in the traveling direction of the wind. 
     Therefore, when an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  by a second pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  is lowered is obtained, the flight controller  100  according to an embodiment of the present disclosure may update aircraft speed-main rotor tilt angle mapping data, such that a tilt angle correcting angle for the main rotors  200 R and  200 L, which is compensated for according to a correcting signal for the tilt angle, decreases based on a current speed of the vertical take-off/landing aircraft  10  and a current tilt angle of the main rotors  200 R and  200 L, like the aircraft speed-main rotor tilt angle mapping data  610 B shown in  FIG. 5B . 
     For example, when the vertical take-off/landing aircraft  10  maintains its speed at 0 km/h in a windy environment, the flight controller  100  may determine 90 degrees as the appropriate tilt angle of the main rotors  200 R and  200 L with reference to the aircraft speed-main rotor tilt angle mapping data  610 A. 
     However, to maintain a hovering position against the wind, when an actual (current) tilt angle of the main rotors  200 R and  200 L is 80 degrees, the flight controller  100  may generate a correcting signal that utilizes 10 degrees, which is a difference angle between the tilt angle according to the aircraft speed-main rotor tilt angle mapping data  610 A and the actual tilt angle, as a correcting angle. Furthermore, the flight controller  100  may control the tilt angle of the main rotors  200 R and  200 L to be 80 degrees according to the correcting signal, and thus, the vertical take-off/landing aircraft  10  may hover against the wind. When no correcting signal is generated, because the ground speed is 0 km/h, the tilt angle is restored to 90 degrees by the aircraft speed-main rotor tilt angle mapping data  610 A and pushed by the wind. 
     In other words, tilt angles of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data  610 A are defined based on inertial speeds without taking air speeds due to wind into account. Therefore, when wind blows around the vertical take-off/landing aircraft  10 , the tilt angles of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data need to be suitably adjusted according to wind strength. 
     Therefore, when an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  by a second pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  is lowered is obtained, the flight controller  100  according to an embodiment of the present disclosure may update aircraft speed-main rotor tilt angle mapping data, such that a tilt angle correcting angle for the main rotors  200 R and  200 L, which is compensated for according to a correcting signal for the tilt angle, decreases (e.g., the tilt angle correcting angle becomes 0 degrees) based on a current speed of the vertical take-off/landing aircraft  10  and a current tilt angle of the main rotors  200 R and  200 L, like the aircraft speed-main rotor tilt angle mapping data  610 B. 
     For example, it may be seen that, when the speed of the vertical take-off/landing aircraft  10  is 15 km/h, a tilt angle according to first mapping data  610 A is approximately 90 degrees, whereas a tilt angle according to second mapping data  610 B is approximately 70 degrees. In other words, when wind is blowing around the vertical take-off/landing aircraft  10 , the tilt angle of the main rotors  200 R and  200 L may be less than the tilt angle of the main rotors  200 R and  200 L in a case where there is no wind. 
     Accordingly, according to the present disclosure, the vertical take-off/landing aircraft  10  may hover and fly at a low speed more stably by actively adopting to changes of the surrounding wind environment. 
       FIG. 6  is a diagram for describing a method of controlling the vertical take-off/landing aircraft  10 , wherein the method is performed by the flight controller  100 , according to an embodiment of the present disclosure. Hereinafter, descriptions identical to those already given above with reference to  FIGS. 1 to 5B  will be omitted, but descriptions will be given below with reference to  FIGS. 1 to 5B  together. 
     The flight controller  100  according to an embodiment of the present disclosure may obtain an aircraft steering signal including a vertical posture control signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  by the first pitch posture angle. 
     In the present disclosure, the ‘aircraft steering signal’ refers to a signal for steering the vertical take-off/landing aircraft  10 . The aircraft steering signal may be received from a user terminal (not shown) or may be generated by the flight controller  100  according to a pre-set flight schedule. 
     Such an aircraft steering signal may include a signal for controlling the posture of an aircraft in horizontal directions and a signal for controlling the posture of the aircraft in vertical directions. 
     For example, a signal for controlling the posture in the horizontal directions may include a signal for controlling speed in the horizontal directions, a signal for controlling a horizontal rolling direction, etc. Also, the signal for controlling the posture in the horizontal directions may include a signal for controlling the heading direction of the vertical take-off/landing aircraft  10  to the direction in which wind blows. Moreover, a signal for controlling the posture in the vertical directions may include a signal for controlling speed in the vertical directions, a signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10 , etc. However, these are merely examples, and an aircraft steering signal may further include various signals in addition to the above-described signals or may not include at least some of the above-described signals. 
     Moreover, an aircraft steering signal may include a vertical posture control signal for increasing the pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  descends as the head wind  500  becomes stronger. 
     Therefore, the flight controller  100  according to an embodiment of the present disclosure may generate a pitch posture angle control signal for lowering the nose of the vertical take-off/landing aircraft  10  to maintain the hovering state as the wind becomes stronger. 
     In other words, the flight controller  100  according to an embodiment of the present disclosure may generate a pitch posture angle control signal, such that the front portion of the vertical take-off/landing aircraft  10  becomes lower than the rear portion as the wind becomes stronger. 
     The pitch posture angle control signal generated by the flight controller may be transmitted to the auxiliary rotor  300  and used to adjust the pitch posture angle of the vertical take-off/landing aircraft  10 . At this time, the pitch posture angle control signal may include at least one of a signal for controlling the number of rotations of the auxiliary rotor  300  and a signal for controlling the collective pitch angle of the auxiliary rotor  300 . 
     In some embodiments, the pitch posture angle control signal generated by the flight controller may be transmitted to the main rotors  200 R and  200 L instead of the auxiliary rotor  300  and used for controlling the pitch posture angle of the vertical take-off/landing aircraft  10 . At this time, the pitch posture angle control signal may include at least one of a signal for controlling the cyclic pitch angle of the main rotors  200 R and  200 L and a signal for controlling the angle of the vane control surface of the main rotors  200 R and  200 L. 
     The flight controller  100  according to an embodiment of the present disclosure may determine the tilt angle of the main rotors  200 R and  200 L with reference to the above-stated first pitch posture angle and generate a tilt angle control signal for the main rotors  200 R and  200 L based on the determined tilt angle. Of course, the generated tilt angle control signal for the main rotor may be transmitted to the main rotors  200 R and  200 L and used for controlling the tilt angle of the main rotors  200 R and  200 L. More detailed descriptions thereof will be given below with reference to  FIGS. 4A and 4B  again. 
       FIGS. 4A and 4B  are diagrams for describing a method, performed by the flight controller  100 , of tilting a main rotor  200 R in various environments, according to an embodiment of the present disclosure. 
     For convenience of explanation, descriptions will be given below under an assumption that the vertical take-off/landing aircraft  10  is hovering for landing as shown in  FIG. 3  and the heading direction of the vertical take-off/landing aircraft  10  is opposite to traveling directions of head winds  500 A and  500 B against the vertical take-off/landing aircraft  10 . Also, it is assumed that head wind  500 B of  FIG. 4B  is stronger than head wind  500 A of  FIG. 4A . 
     Referring to  FIG. 4A  under the above-described assumption, the flight controller  100  according to an embodiment of the present disclosure may control the auxiliary rotor  300 , such that the nose of the vertical take-off/landing aircraft  10  descends to maintain a hovering state against the head wind  500 A. 
     At this time, the flight controller  100  may increase the number of rotations of the auxiliary rotor  300  or the collective pitch angle to increase thrust  310 A generated by the auxiliary rotor  300 , and thus, the vertical take-off/landing aircraft  10  may have a pitch posture angle  420 A. 
     Moreover, as described above, the flight controller  100  according to an embodiment of the present disclosure may tilt the main rotor  200 R, such that the rotation axis of the main rotor  200 R becomes more parallel to the ground as the pitch posture angle  420 A changing in the direction in which the nose of the vertical take-off/landing aircraft  10  descends increases. 
     In other words, the flight controller  100  according to an embodiment of the present disclosure may control (a tilt angle  411 A of the main rotor  200 R, such that a tilt angle  411 A decreases as the pitch posture angle  420 A increases. At this time, the tilt angle  411 A may refer to an angle defined in the direction of the rotation axis vector  410 A of the main rotor  200 R in the X′, Y′, and Z′ coordinate system as described above with reference to  FIG. 1 . 
     The main rotor  200 R may generate thrust  210 RA according to the changed tilt angle  411 A, such that the vertical take-off/landing aircraft  10  may stably hover. 
     On the other hand, referring to  FIG. 4B  in contrast to  FIG. 4A , the flight controller  100  according to an embodiment of the present disclosure may control the auxiliary rotor  300 , such that the nose of the vertical take-off/landing aircraft  10  is further lowered to maintain a hovering state against stronger head wind  500 B. 
     At this time, the flight controller  100  may increase the number of rotations of the auxiliary rotor  300  or the collective pitch angle to increase thrust  310 B generated by the auxiliary rotor  300  more than the thrust  310 A of  FIG. 4A , and thus, the vertical take-off/landing aircraft  10  may have a greater pitch posture angle  420 B. 
     Moreover, as described above, the flight controller  100  according to an embodiment of the present disclosure may tilt the main rotor  200 R, such that the rotation axis of the main rotor  200 R becomes more parallel to the ground as the pitch posture angle  420 A changing in the direction in which the nose of the vertical take-off/landing aircraft  10  descends increases. 
     In other words, the flight controller  100  according to an embodiment of the present disclosure may control a tilt angle  411 B of the main rotor  200 R, such that a tilt angle  411 B decreases as the pitch posture angle  420 B increases. At this time, the tilt angle  411 B may refer to an angle defined in the direction of the rotation axis vector  410 B of the main rotor  200 R in the X′, Y′, and Z′ coordinate system as described above with reference to  FIG. 1 . 
     The main rotor  200 R may generate thrust  210 RB according to the smaller tilt angle  411 B, such that the vertical take-off/landing aircraft  10  may stably hover against the strong head wind  500 B. 
     The flight controller  100  according to an embodiment of the present disclosure may perform the operations described with respect to  FIGS. 4A and 4B  only when the speed of the vertical take-off/landing aircraft  10  is less than or equal to a predetermined critical speed. In other words, when it is necessary for the vertical take-off/landing aircraft  10  to maintain a constant flight position for take-off or landing or to fly at a desired speed, the flight controller  100  according to an embodiment of the present disclosure may generate tilt angle control signals for main rotors in correspondence to a vertical posture control signal. 
     Also, the flight controller  100  according to an embodiment of the present disclosure may also perform the controls according to the descriptions given above with reference to  FIGS. 4A and 4B  with respect to a left main rotor  200 L. 
     On the other hand, according to the method of controlling the vertical take-off/landing aircraft  10 , wherein the method is performed by the flight controller  100  according to an embodiment of the present disclosure, after a tilt angle control signal for the main rotors  200 R and  200 L as described above is generated, a correcting signal including a tilt angle correcting angle for the main rotors  200 R and  200 L may be generated based on pre-set aircraft speed-main rotor tilt angle mapping data. 
     In the present disclosure, the ‘tilt angle correcting angle’ may refer to an angle for correcting a tilt angle calculated by the flight controller  100  through the above-described process. Also, the ‘aircraft speed-main rotor tilt angle mapping data’ may refer to data including a tilt angle of the main rotors  200 R and  200 L at each speed of an aircraft. More detailed descriptions thereof will be given below with reference to  FIGS. 5A and 5B  again. 
       FIG. 5A  is a diagram showing an example of aircraft speed-main rotor tilt angle mapping data  610 A according to an embodiment of the present disclosure. 
     The flight controller  100  according to an embodiment of the present disclosure may check the speed of the vertical take-off/landing aircraft  10  and determine a tilt angle of the main rotors  200 R and  200 L at the corresponding speed with reference to the aircraft speed-main rotor tilt angle mapping data  610 A. For example, when the speed of the vertical take-off/landing aircraft  10  is 0 km/h, the flight controller  100  may determine 90 degrees as the tilt angle of the main rotors  200 R and  200 L. 
     Subsequently, the flight controller  100  according to an embodiment of the present disclosure may compare the tilt angle of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data  610 A with a current tilt angle of the main rotors  200 R and  200 L and calculate a difference angle therebetween. Also, the flight controller  100  may generate a correcting signal including a tilt angle correcting angle for the main rotors  200 R and  200 L based on the difference angle. 
     For example, as in the above-stated example, when there is no wind and the inertial speed of the vertical take-off/landing aircraft  10  is 0 km/h, the flight controller  100  may determine 90 degrees as the appropriate tilt angle of the main rotors  200 R and  200 L. However, when wind blows, a tilt instruction is generated by a pitch posture angle instruction to maintain a hovering position, and an actual (current) tilt angle of the main rotors  200 R and  200 L is 80 degrees, the flight controller  100  may generate a correcting signal that utilizes 10 degrees, which is a difference angle between the tilt angle according to the aircraft speed-main rotor tilt angle mapping data  610 A and the actual tilt angle, as a correcting angle. However, because tilt angles of the main rotors  200 R and  200 L according to the above-stated aircraft speed-main rotor tilt angle mapping data  610 A are only based on cases without wind, the tilt angles of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data  610 A may not be suitable for the vertical take-off/landing aircraft  10  when wind blows. 
     Therefore, when the flight controller  100  according to an embodiment of the present disclosure obtains an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  in the direction of lowering the nose of the vertical take-off/landing aircraft  10  by a second pitch posture angle to offset the influence caused by the wind, the flight controller  100  may update aircraft speed-main rotor tilt angle mapping data, such that a tilt correcting angle for the main rotors  200 R and  200 L, which is corrected according to a tilt angle correcting signal, decreases based on a current speed of the vertical take-off/landing aircraft  10  and a current tilt angle of the main rotors  200 R and  200 L. 
       FIG. 5B  is a diagram showing an example of aircraft speed-main rotor tilt angle mapping data  610 B updated by the flight controller  100  according to an embodiment of the present disclosure. 
     As described above, tilt angles of the main rotors  200 R and  200 L of the vertical take-off/landing aircraft  10  according to the aircraft speed-main rotor tilt angle mapping data  610 A are related to inertial speeds that do not take the influence of the wind into account. Therefore, when wind blows, the vertical take-off/landing aircraft  10  may be pushed in the direction in which the wind blows and its position may be changed. 
     Therefore, when an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  by a second pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  is lowered is obtained, the flight controller  100  according to an embodiment of the present disclosure may update aircraft speed-main rotor tilt angle mapping data, such that a tilt angle correcting angle for the main rotors  200 R and  200 L, which is compensated for according to a correcting signal for the tilt angle, decreases based on a current speed of the vertical take-off/landing aircraft  10  and a current tilt angle of the main rotors  200 R and  200 L, like the aircraft speed-main rotor tilt angle mapping data  610 B shown in  FIG. 5B . 
     For example, when the vertical take-off/landing aircraft  10  maintains a hovering position in a windy environment, the flight controller  100  may determine 90 degrees as the appropriate tilt angle of the main rotors  200 R and  200 L with reference to the aircraft speed-main rotor tilt angle mapping data  610 A. 
     However, when a pitch posture instruction is generated to maintain a current position against the wind, a tilt angle instruction is generated thereby, and the tilt angle of the main rotors  200 R and  200 L is 80 degrees, and the flight controller  100  may generate a correcting signal that utilizes 10 degrees, which is a difference angle between the tilt angle according to the aircraft speed-main rotor tilt angle mapping data  610 A and the actual tilt angle, as a correcting angle. Furthermore, the flight controller  100  may maintain the tilt angle of the main rotors  200 R and  200 L to be 80 degrees according to the correcting signal, and thus, the vertical take-off/landing aircraft  10  may maintains its position and hover even in a windy environment. 
     In other words, tilt angles of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data  610 A are defined without taking air speeds due to wind into account. Therefore, when wind blows around the vertical take-off/landing aircraft  10 , the tilt angles of the main rotors  200 R and  200 L according to the aircraft speed-main rotor tilt angle mapping data need to be suitably adjusted according to a correcting signal. 
     Therefore, when an aircraft steering signal for changing the pitch posture angle of the vertical take-off/landing aircraft  10  by a second pitch posture angle in the direction in which the nose of the vertical take-off/landing aircraft  10  is lowered is obtained, the flight controller  100  according to an embodiment of the present disclosure may update aircraft speed-main rotor tilt angle mapping data, such that a tilt angle correcting angle for the main rotors  200 R and  200 L, which is compensated for according to a correcting signal for the tilt angle, decreases (e.g., the tilt angle correcting angle becomes 0 degrees) based on a current speed of the vertical take-off/landing aircraft  10  and a current tilt angle of the main rotors  200 R and  200 L, like the aircraft speed-main rotor tilt angle mapping data  610 B. 
     For example, it may be seen that, when the speed of the vertical take-off/landing aircraft  10  is 15 km/h, a tilt angle according to first mapping data  610 A is approximately 90 degrees, whereas a tilt angle according to second mapping data  610 B is approximately 70 degrees. In other words, when wind is blowing around the vertical take-off/landing aircraft  10 , the tilt angle of the main rotors  200 R and  200 L may be less than the tilt angle of the main rotors  200 R and  200 L in a case where there is no wind. 
     Accordingly, according to the present disclosure, an instruction for tilting the main rotors  200 R and  200 L may be automatically generated based on a vertical posture control signal under a low-speed flight condition where it is difficult to directly measure a wind speed. Therefore, the tilt angle of the main rotors  200 R and  200 L may be actively compensated for according to changes of the air speed due to wind. 
     The embodiments according to the present disclosure described above may be implemented in the form of a computer program that may be executed through various components on a computer, and such a computer program may be recorded on a computer-readable recording medium. At this time, the medium may be to store a program executable by a computer. Examples of the medium include magnetic media, such as a hard disk, a floppy disk, and magnetic tape, optical recording media, such as CD-ROMs and DVDs, magneto-optical media such as a floptical disk, and ROM, RAM, and a flash memory, which are configured to store program instructions. 
     Moreover, the computer program may be specially designed and configured for the present disclosure or may be known and available to one of ordinary skill in the computer software field. Examples of computer programs may include machine language code such as code generated by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like. 
     Particular implementations described in the disclosure are merely embodiments and do not limit the scope of the disclosure in any way. For brevity of description, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of the systems may be omitted. Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. Also, unless specifically mentioned as “essential,” “important,” components may not be necessary components for the application of the present disclosure. 
     Therefore, the spirit of the disclosure should not be limited to the above-described embodiments, and the scope of the spirit of the disclosure is defined not only in the claims below, but also in the ranges equivalent to or equivalent to the claims.