Posture control device

Abstract

The present application provides a kind of posture control device.Rotor control device (50) has vertical rotor control part (72), horizontal rotor control part (74) and distribution instruction value calculation part (66), wherein, the vertical rotor control part (72) according to the 1st distribution instruction value controls each VTOL rotor (18);The horizontal rotor control part (74) according to the 2nd distribution instruction value controls each cruise rotor (22);The distribution instruction value calculation part (66) sets the 1st distribution instruction value as the difference of the instruction value of yaw moment and the 2nd distribution instruction value, sets the size of the 2nd distribution instruction value as 0 in the case where the instruction value of yaw moment is less than threshold value, sets the size of the 2nd distribution instruction value as greater than 0 in the case where the instruction value of yaw moment is above threshold value.Accordingly, the posture of fuselage can be stabilized.

Description

TECHNICAL FIELD

[0001] The present application relates to a posture control device. BACKGROUND

[0002] A VTOL aircraft is disclosed in the specification of U.S. Patent Application Publication No. 2021 / 0245873. The VTOL aircraft rotates in a yaw direction by making a difference between a rotation speed of a vertical rotor rotating in a first direction and a rotation speed of a vertical rotor rotating in a second direction. SUMMARY

[0003] In the technology disclosed in the specification of U.S. Patent Application Publication No. 2021 / 0245873, there is a technical problem that a yaw moment of a required size cannot be generated by the vertical rotors in a case where the required yaw moment is excessively large, thereby failing to stabilize the posture of the fuselage.

[0004] An object of the present application is to solve the above-described technical problem.

[0005] A posture control device according to an embodiment of the present application is a posture control device that performs posture control of a fuselage of an aircraft having a plurality of vertical rotors that generate thrust in a vertical direction and a plurality of horizontal rotors that generate thrust in a horizontal direction, the posture control device including a yaw moment command value calculation section that calculates a command value of a yaw moment acting on the fuselage, a distribution command value calculation section that calculates a first distribution command value and a second distribution command value in accordance with the command value of the yaw moment, a vertical rotor control section that controls each of the vertical rotors in accordance with the first distribution command value, and a horizontal rotor control section that controls each of the horizontal rotors in accordance with the second distribution command value, wherein the distribution command value calculation section sets the first distribution command value as a difference between the command value of the yaw moment and the second distribution command value, and in a case where the command value of the yaw moment is smaller than a threshold value, the distribution command value calculation section sets a magnitude of the second distribution command value to 0, and in a case where the command value of the yaw moment is equal to or larger than the threshold value, the distribution command value calculation section sets the magnitude of the second distribution command value to be larger than 0.

[0006] According to the present application, it is possible to stabilize the posture of the fuselage.

[0007] The above objects, features, and advantages will be easily understood by the following description of the embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a schematic view of an aircraft.

[0009] Figure 2 is a diagram showing the structure of the power supply system.

[0010] Figure 3 is a diagram showing the structure of the power supply system.

[0011] Figure 4 is a control block diagram of the rotor control device.

[0012] Figure 5 is a graph showing an example of the time variation of the yaw moment command value, the moving average of the yaw moment command value, and the 2nd distribution command value.

[0013] Figure 6 is a flowchart showing the processing flow of the rotor control performed in the rotor control device. DETAILED DESCRIPTION

[0014] [1st Embodiment]

[0015] [Structure of Airplane]

[0016] Figure 1 is a schematic view of the airplane 10. The airplane 10 of the present embodiment is an electric vertical takeoff and landing airplane (eVTOL airplane). The airplane 10 of the present embodiment drives the rotors by electric motors. The airplane 10 of the present embodiment generates vertical thrust and horizontal thrust by the rotors. In addition, the airplane 10 of the present embodiment is a hybrid airplane. The airplane 10 of the present embodiment has an electric generator and a battery as a power source of the electric motor.

[0017] The airplane 10 has a fuselage 12. A cockpit, a cabin, and the like are provided in the fuselage 12. A pilot is seated in the cockpit, and the airplane 10 is manipulated. A passenger or the like is seated in the cabin. The airplane 10 can also be automatically manipulated without a pilot.

[0018] The airplane 10 has a front wing 14 and a rear wing 16. The front wing 14 is installed at a position further forward than the center of gravity G of the fuselage 12. The rear wing 16 is installed at a position further rearward than the center of gravity G of the fuselage 12. When the airplane 10 moves forward, the front wing 14 and the rear wing 16 each generate lift.

[0019] The airplane 10 has eight VTOL rotors 18. The eight VTOL rotors 18 are rotors 18Fla, 18FLb, 18RLa, 18RLb, 18Fra, 18FRb, 18RRa, and 18RRb. The VTOL rotors 18 each correspond to the vertical rotor of the present application.

[0020] The rotor 18Fla, the rotor 18FLb, the rotor 18RLa, and the rotor 18RLb are mounted to the boom 20L. The boom 20L extends in the front-rear direction. The boom 20L is mounted to the front wing 14 and the rear wing 16. The boom 20L is disposed to the left side of the center of gravity G. That is, the rotor 18Fla, the rotor 18FLb, the rotor 18RLa, and the rotor 18RLb are configured to the left side of the center of gravity G.

[0021] The rotor 18Fra, the rotor 18FRb, the rotor 18RRa, and the rotor 18RRb are mounted to the boom 20R. The boom 20R extends in the front-rear direction. The boom 20R is mounted to the front wing 14 and the rear wing 16. The boom 20R is disposed to the right side of the center of gravity G. That is, the rotor 18Fra, the rotor 18FRb, the rotor 18RRa, and the rotor 18RRb are configured to the right side of the center of gravity G.

[0022] In a state where the aircraft 10 is observed from above, the rotor 18Fla, the rotor 18RLa, the rotor 18FRb, and the rotor 18RRb rotate to the left, respectively. In a state where the aircraft 10 is observed from above, the rotor 18Fra, the rotor 18RRa, the rotor 18FLb, and the rotor 18RLb rotate to the right, respectively.

[0023] Each rotation axis (not shown) of the VTOL rotor 18 extends in the up-down direction. The VTOL rotor 18 controls the thrust by adjusting the rotation speed and the pitch angle of the blade, respectively. The VTOL rotor 18 is used at the time of vertical takeoff, at the time of transition from vertical takeoff to cruising, at the time of transition from cruising to vertical landing, at the time of vertical landing, at the time of hovering in the air, and the like, respectively. In addition, the VTOL rotor 18 is used at the time of attitude control, respectively. Each rotation axis of the VTOL rotor 18 can also have an angle (tilt) of several degrees with respect to the up-down direction.

[0024] The lift-up thrust is generated by controlling the thrust of each of the eight VTOL rotors 18. The lift-up thrust indicates the thrust in the vertical direction. The magnitude of the lift-up thrust is determined from the sum of the thrusts of the eight VTOL rotors 18.

[0025] The roll moment is exerted on the fuselage 12 by controlling the thrust of each of the eight VTOL rotors 18. The magnitude of the roll moment is determined from the difference between the sum of the thrusts of the four VTOL rotors 18 configured to the left side of the center of gravity G and the sum of the thrusts of the four VTOL rotors 18 configured to the right side of the center of gravity G.

[0026] The four VTOL rotors 18 disposed on the left side of the center of gravity G with respect thereto are referred to as the rotors 18Fla, 18FLb, 18RLa, and 18RLb. The four VTOL rotors 18 disposed on the right side of the center of gravity G with respect thereto are referred to as the rotors 18Fra, 18FRb, 18RRa, and 18RRb.

[0027] A pitch moment is exerted on the fuselage 12 by controlling the respective thrusts of the eight VTOL rotors 18. The magnitude of the pitch moment is determined from the difference between the sum of the respective thrusts of the four VTOL rotors 18 disposed on the front side of the center of gravity G with respect thereto and the sum of the respective thrusts of the four VTOL rotors 18 disposed on the rear side of the center of gravity G with respect thereto.

[0028] The four VTOL rotors 18 disposed on the front side of the center of gravity G with respect thereto are referred to as the rotors 18Fla, 18FLb, 18Fra, and 18FRb. The four VTOL rotors 18 disposed on the rear side of the center of gravity G with respect thereto are referred to as the rotors 18RLa, 18RLb, 18RRa, and 18RRb.

[0029] A yaw moment is exerted on the fuselage 12 by controlling the respective counter torques of the eight VTOL rotors 18. The magnitude of the yaw moment is determined from the difference between the sum of the respective counter torques of the four VTOL rotors 18 rotating to the left and the sum of the respective counter torques of the four VTOL rotors 18 rotating to the right.

[0030] In the case where the respective rotation axes of the VTOL rotors 18 have an angle (tilt) of several degrees with respect to the up-down direction, a thrust is generated in the lateral direction of the fuselage 12 by the VTOL rotors 18. In this case, in addition to the difference between the sum of the counter torques described above, the magnitude of the yaw moment is determined from the difference between the moment generated by the thrust generated to the left rotation direction of the fuselage 12 and the moment generated by the thrust generated to the right rotation direction of the fuselage 12.

[0031] The four VTOL rotors 18 rotating to the left are referred to as the rotors 18Fla, 18RLa, 18FRb, and 18RRb. The four VTOL rotors 18 rotating to the right are referred to as the rotors 18Fra, 18RRa, 18FLb, and 18RLb.

[0032] The aircraft 10 has two cruise rotors 22. The two cruise rotors 22 are referred to as the rotors 22L and 22R. The cruise rotors 22 respectively correspond to the horizontal rotors of the present application.

[0033] The rotor 22L is disposed on the left side of the center line A of the fuselage 12. The rotor 22R is disposed on the right side of the center line A of the fuselage 12.

[0034] The rotating shafts (not shown) of the respective VTOL rotors 18 extend in the vertical direction. The VTOL rotors 18 are used at the time of takeoff and landing, and the like. The VTOL rotors 18 are also used at the time of attitude control. The rotating shafts of the respective VTOL rotors 18 can also be inclined at several degrees with respect to the vertical direction.

[0035] The VTOL thrust is generated by controlling the respective VTOL rotors 18. The VTOL thrust is the thrust in the vertical direction. The magnitude of the VTOL thrust is determined in accordance with the sum of the respective VTOL thrusts of the two VTOL rotors 18.

[0036] The yawing moment is exerted on the fuselage 12 by controlling the respective VTOL rotors 18. The magnitude of the yawing moment is determined in accordance with the difference between the magnitude of the VTOL thrust of the rotor 18L and the magnitude of the VTOL thrust of the rotor 18R.

[0037] [Structure of the electric power supply system]

[0038] Figure 2 is a diagram showing the structure of the electric power supply system 24. Figure 2 The connection relationship of the four batteries 30 and the twelve electric motors 32 is mainly shown. Figure 3 is a diagram showing the structure of the electric power supply system 24.

[0039] One set of the drive units 26 is provided for each VTOL rotor 18. The drive unit 26FLa is provided for the rotor 18FLa. The drive unit 26FLb is provided for the rotor 18FLb. The drive unit 26RLa is provided for the rotor 18RLa. The drive unit 26RLb is provided for the rotor 18RLb. The drive unit 26FRa is provided for the rotor 18FRa. The drive unit 26FRb is provided for the rotor 18FRb. The drive unit 26RRa is provided for the rotor 18RRa. The drive unit 26RRb is provided for the rotor 18RRb.

[0040] Two sets of the drive units 26 are provided for each cruise rotor 22. The drive unit 26La and the drive unit 26Lb are provided for the rotor 22L. The drive unit 26Ra and the drive unit 26Rb are provided for the rotor 22R.

[0041] One battery 30 is connected to each of the three drive units 26. Battery 30a is connected to drive units 26Fra, 26RLa, and 26Ra. Battery 30b is connected to drive units 26Fla, 26RRa, and 26La. Battery 30c is connected to drive units 26FRb, 26RLb, and 26Rb. Battery 30d is connected to drive units 26FLb, 26RRb, and 26Lb.

[0042] Each drive unit 26 has an electric motor 32 and an inverter 34. The electric motor 32 is a three-phase electric motor. The output shaft of the electric motor 32 (not shown) is connected to the rotation shaft of each VTOL rotor 18 or the rotation shaft of the cruise rotor 22. The inverter 34 converts the input DC power into three-phase AC power and outputs it to the electric motor 32.

[0043] like Figure 3 As shown, drive module 36 is composed of three sets of drive units 26 and one battery 30. Drive module 36a is composed of drive unit 26Fra, drive unit 26RLa, drive unit 26Ra and battery 30a. Drive module 36b is composed of drive unit 26Fla, drive unit 26RRa, drive unit 26La and battery 30b. Drive module 36c is composed of drive unit 26FRb, drive unit 26RLb, drive unit 26Rb and battery 30c. Drive module 36d is composed of drive unit 26FLb, drive unit 26RRb, drive unit 26Lb and battery 30d.

[0044] Each drive module 36 is connected to the power generation module 38. The power generation module 38 has an engine 40, an electric generator 42, and a power control unit (hereinafter referred to as PCU) 44.

[0045] Engine 40 is a gas turbine engine. Engine 40 can also be a reciprocating engine. Electric generator 42 functions as a three-phase electric motor and also as a three-phase generator. The rotating shaft (not shown) of electric generator 42 is connected to the output shaft (not shown) of engine 40.

[0046] PCU44 is an inverter and converter. PCU44 converts the three-phase AC power input from the electric generator 42 into DC power and outputs it. In addition, PCU44 converts the DC power input from each battery 30 into three-phase AC power and outputs it to the electric generator 42.

[0047] like Figure 3As shown, each drive module 36 has a switch 48. Each switch 48 has a switching element such as an IGBT and a diode. Each switch 48 always allows the supply of electric power from the power generation module 38 to the drive module 36. Each switch 48 allows the supply of electric power from the drive module 36 to the power generation module 38 in the case where it is in an on state.

[0048] In the case where each switch 48 is in an on state, electric power is supplied from each battery 30 to the motor generator 42. By virtue of this, the motor generator 42 operates, and the engine 40 is started. In the case where the engine 40 is operating, electric power generated by the motor generator 42 is supplied to each battery 30 and each electric motor 32. By virtue of this, each battery 30 is charged. In addition, each electric motor 32 operates.

[0049] In addition, in Figure 2 and Figure 3 , a general outline of the electric power supply system 24 is shown. Figure 2 and Figure 3 The electric power supply system 24 shown in

[0050] [Structure of Rotor Control Device]

[0051] Figure 4 is a control block diagram of the rotor control device 50. The rotor control device 50 performs control of the thrust of each VTOL rotor 18 and control of the thrust of each cruise rotor 22. The rotor control device 50 corresponds to the attitude control device of the present application. The rotor control device 50 has an arithmetic unit 52 and a storage unit 54.

[0052] The arithmetic unit 52 has, for example, a processor such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and the like. The arithmetic unit 52 has a lift thrust command value calculation unit 56, a roll moment command value calculation unit 58, a pitch moment command value calculation unit 60, a yaw moment command value calculation unit 62, a cruise thrust command value calculation unit 64, a distribution command value calculation unit 66, a VTOL rotor thrust command value generation unit 68, a cruise rotor thrust command value generation unit 70, a VTOL rotor control unit 72, and a cruise rotor control unit 74.

[0053] The lift thrust command value calculation section 56, the roll moment command value calculation section 58, the pitch moment command value calculation section 60, the yaw moment command value calculation section 62, the cruise thrust command value calculation section 64, the distribution command value calculation section 66, the VTOL rotor thrust command value generation section 68, the cruise rotor thrust command value generation section 70, the VTOL rotor control section 72, and the cruise rotor control section 74 are realized by the arithmetic section 52 executing a program stored in the storage section 54.

[0054] At least a part of the lift thrust command value calculation section 56, the roll moment command value calculation section 58, the pitch moment command value calculation section 60, the yaw moment command value calculation section 62, the cruise thrust command value calculation section 64, the distribution command value calculation section 66, the VTOL rotor thrust command value generation section 68, the cruise rotor thrust command value generation section 70, the VTOL rotor control section 72, and the cruise rotor control section 74 can also be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0055] At least a part of the lift thrust command value calculation section 56, the roll moment command value calculation section 58, the pitch moment command value calculation section 60, the yaw moment command value calculation section 62, the cruise thrust command value calculation section 64, the distribution command value calculation section 66, the VTOL rotor thrust command value generation section 68, the cruise rotor thrust command value generation section 70, the VTOL rotor control section 72, and the cruise rotor control section 74 can also be realized by an electronic circuit including discrete devices.

[0056] The storage section 54 is constituted by a not-illustrated volatile memory and a not-illustrated non-volatile memory as a computer-readable storage medium. The volatile memory is, for example, a RAM (Random Access Memory) or the like. The non-volatile memory is, for example, a ROM (Read Only Memory), a flash memory, or the like. Data and the like are stored in the volatile memory, for example. Programs, tables, maps, and the like are stored in the non-volatile memory, for example. At least a part of the storage section 54 can also be provided to the above-described processor, integrated circuit, or the like.

[0057] The ascending thrust command value calculation section 56 calculates an ascending thrust command value. The ascending thrust command value is determined, for example, in accordance with an operation amount of an operation input section by the pilot. The operation input section is, for example, a stick, a pedal, a lever member, or the like. The operation amount of the operation input section and the ascending thrust command value can not be one-to-one correspondence. The ascending thrust command value can be made variable with respect to the operation amount of the operation input section, for example, in accordance with an operation range of the operation input section, an operation speed of the operation input section, a height of the fuselage 12, or the like. The height of the fuselage 12 is estimated, for example, in accordance with a distance between the ground and the fuselage 12 detected by a ground distance meter (not shown). The height of the fuselage 12 is estimated, for example, in accordance with a signal received from a GNSS (Global Navigation Satellite System).

[0058] In a case where the pilot does not input an operation to the operation input section, the ascending thrust command value can be determined automatically regardless of the operation amount of the operation input section, and hovering can be performed. In a case where the aircraft 10 is automatically controlled, the ascending thrust command value can be determined automatically regardless of the operation amount of the operation input section in accordance with a flight path set in advance.

[0059] The roll moment command value calculation section 58 calculates a roll moment command value. The roll moment command value is determined in accordance with an operation amount of an operation input section by the pilot. The operation amount of the operation input section and the roll moment command value can not be one-to-one correspondence. The roll moment command value can be made variable with respect to the operation amount of the operation input section, for example, in accordance with an operation range of the operation input section, an operation speed of the operation input section, an angular velocity of the fuselage 12, or the like. The angular velocity of the fuselage 12 is detected, for example, by a gyro sensor (not shown).

[0060] In a case where the pilot does not input an operation to the operation input section, the roll moment command value can be determined automatically regardless of the operation amount of the operation input section, and hovering can be performed. In a case where the aircraft 10 is automatically controlled, the roll moment command value can be determined automatically regardless of the operation amount of the operation input section in accordance with a flight path set in advance.

[0061] The pitch moment command value calculation section 60 calculates a pitch moment command value. The pitch moment command value is determined, for example, in accordance with an operation amount of an operation input section by the pilot. The operation amount of the operation input section and the pitch moment command value can not be one-to-one correspondence. The pitch moment command value can be made variable with respect to the operation amount of the operation input section, for example, in accordance with an operation range of the operation input section, an operation speed of the operation input section, an angular velocity of the fuselage 12, or the like.

[0062] In the case where the pilot does not perform an input operation to the operation input section, the pitch moment command value can be automatically determined irrespective of the operation amount of the operation input section, and hovering can be performed. In the case where the aircraft 10 is automatically controlled, the pitch moment command value can be automatically determined irrespective of the operation amount of the operation input section in accordance with a flight path set in advance.

[0063] The yaw moment command value calculation section 62 calculates a yaw moment command value. The yaw moment command value is determined, for example, in accordance with the operation amount of the operation input section by the pilot. The operation amount of the operation input section and the yaw moment command value can not be one-to-one correspondence. The yaw moment command value can be made variable with respect to the operation amount of the operation input section in accordance with the operation range of the operation input section, the operation speed of the operation input section, the angular velocity of the fuselage 12, and the like.

[0064] In the case where the pilot does not perform an input operation to the operation input section, the yaw moment command value can be automatically determined irrespective of the operation amount of the operation input section, and hovering can be performed. In the case where the aircraft 10 is automatically controlled, the yaw moment command value can be automatically determined irrespective of the operation amount of the operation input section in accordance with a flight path set in advance.

[0065] The cruise thrust command value calculation section 64 calculates a cruise thrust command value. The cruise thrust command value is determined, for example, in accordance with the operation amount of the operation input section by the pilot. The operation amount of the operation input section and the cruise thrust command value can not be one-to-one correspondence. The cruise thrust command value can be made variable with respect to the operation amount of the operation input section in accordance with the operation range of the operation input section, the operation speed of the operation input section, the airspeed of the fuselage 12, and the like. The airspeed of the fuselage 12 is detected, for example, by an airspeed sensor (not shown).

[0066] In the case where the pilot does not perform an input operation to the operation input section, the cruise thrust command value can be automatically determined, and the aircraft 10 can fly at a certain speed. In the case where the aircraft 10 is automatically controlled, the cruise thrust command value can be automatically determined irrespective of the operation amount of the operation input section in accordance with a flight path set in advance.

[0067] The distribution command value calculation section 66 calculates a first distribution command value and a second distribution command value. The first distribution command value is a command value of the yaw moment command value that is generated by the eight VTOL rotors 18. The second distribution command value is a command value of the yaw moment command value that is generated by the two cruise rotors 22.

[0068] Figure 5 is a graph showing an example of the time variation of the yaw moment command value, the moving average of the yaw moment command value, and the second distribution command value.

[0069] The distribution command value calculating portion 66 sets the first distribution command value to the difference between the yaw moment command value and the second distribution command value. In the case where the moving average of the yaw moment command value is smaller than the threshold value, the distribution command value calculating portion 66 sets the magnitude of the second distribution command value to 0. In the case where the moving average of the yaw moment command value is equal to or larger than the threshold value, the distribution command value calculating portion 66 sets the magnitude of the second distribution command value to be larger than 0. Specifically, the distribution command value calculating portion 66 sets the second distribution command value to the difference between the moving average of the yaw moment command value and the threshold value.

[0070] Accordingly, the steady component in the yaw moment command value is set to the second distribution command value. The unsteady component in the yaw moment command value is set to the first distribution command value. That is, the component in the yaw moment command value that varies drastically is distributed as the command value for the VTOL rotor 18, and the component that varies gently is distributed as the command value for the cruise rotor 22.

[0071] The threshold value is a predetermined value. The distribution command value calculating portion 66 can also set the threshold value to be variable. For example, in the case where a part of the eight VTOL rotors 18 malfunctions, the distribution command value calculating portion 66 can also decrease the threshold value. The distribution command value calculating portion 66 can also set the threshold value in accordance with the number of the VTOL rotors 18 that malfunction among the eight VTOL rotors 18, for example. In addition, the distribution command value calculating portion 66 can also set the threshold value to be variable in accordance with the airspeed of the fuselage 12. For example, in the case where the airspeed is equal to or larger than a prescribed speed, the threshold value can also be decreased as the airspeed is larger.

[0072] The VTOL rotor thrust command value generating portion 68 generates the thrust command value for each VTOL rotor 18. The VTOL rotor thrust command value generating portion 68 generates the thrust command value in accordance with the lift thrust command value, the roll moment command value, the pitch moment command value, and the first distribution command value.

[0073] The cruise rotor thrust command value generating portion 70 generates the thrust command value for each cruise rotor 22. The cruise rotor thrust command value generating portion 70 generates the thrust command value in accordance with the cruise thrust command value and the second distribution command value.

[0074] The VTOL rotor control portion 72 controls the thrust of each VTOL rotor 18 in accordance with the thrust command value for each VTOL rotor 18. The VTOL rotor control portion 72 corresponds to the vertical rotor control portion of the present application.

[0075] The cruise rotor control portion 74 controls the thrust of each cruise rotor 22 in accordance with the thrust command value for each cruise rotor 22. The cruise rotor control portion 74 corresponds to the horizontal rotor control portion of the present application.

[0076] [Rotors Control]

[0077] Figure 6 Fig. 8 is a flowchart showing a processing flow of the rotor control performed in the rotor control device 50. The processing of the rotor control is repeatedly executed at a prescribed period during flight of the aircraft 10.

[0078] In step S1, the distribution command value calculation section 66 calculates the 1st distribution command value and the 2nd distribution command value. Thereafter, the processing is transferred to step S2.

[0079] In step S2, the VTOL rotor thrust command value generation section 68 generates a thrust command value for each VTOL rotor 18. The VTOL rotor thrust command value generation section 68 generates the thrust command value in accordance with the lift thrust command value, the roll moment command value, the pitch moment command value, and the 1st distribution command value. Thereafter, the processing is transferred to step S3.

[0080] In step S3, the cruise rotor thrust command value generation section 70 generates a thrust command value for each cruise rotor 22. The cruise rotor thrust command value generation section 70 generates the thrust command value in accordance with the cruise thrust. Thereafter, the processing is transferred to step S4.

[0081] In step S4, the VTOL rotor control section 72 controls the thrust of each VTOL rotor 18 in accordance with the thrust command value for each VTOL rotor 18. Thereafter, the processing is transferred to step S5.

[0082] In step S5, the cruise rotor control section 74 controls the thrust of each cruise rotor 22 in accordance with the thrust command value for each cruise rotor 22. Thereafter, the processing of the rotor control is ended.

[0083] [Effects]

[0084] In the aircraft 10 of the present embodiment, the rotor control device 50 acts the roll moment, the pitch moment, and the yaw moment on the fuselage 12 by causing the thrust of the eight VTOL rotors 18 to differ. Thereby, the rotor control device 50 performs the attitude control that stabilizes the attitude of the fuselage 12. Even in the case where the attitude control of the fuselage 12 is performed, it is necessary to secure the lift thrust of the eight VTOL rotors 18 in order to prevent a sharp descent of the aircraft 10. The proportion of the thrust generated in each VTOL rotor 18 in order to secure the lift thrust with respect to the upper limit of the thrust that can be generated in each VTOL rotor 18 is large. Therefore, it is sometimes not possible to cause the thrust of the plurality of VTOL rotors 18 to differ by a sufficient size while securing the lift thrust.

[0085] Therefore, the rotor control device 50 of the present embodiment generates the yaw moment by the 8 VTOL rotors 18 and generates the yaw moment by the 2 cruise rotors 22. According to this, the rotor control device 50 of the present embodiment can make the yaw moment generated by the 8 VTOL rotors 18 smaller than the yaw moment command value calculated in the yaw moment command value calculation section 62. Therefore, the thrust of each VTOL rotor 18 can be allocated more for the control of the roll moment and the pitch moment. As a result, the difference in the thrust of each VTOL rotor 18 can be increased. Therefore, in the roll direction and the pitch direction, the attitude of the fuselage 12 can be stabilized at an early stage. According to this, the rotor control device 50 of the present embodiment can stabilize the attitude of the fuselage 12 at an early stage in the roll direction and the pitch direction while also stabilizing the attitude of the fuselage 12 at an early stage in the yaw direction.

[0086] In the case where the magnitude of the cruise thrust command value is large, in order to generate the cruise thrust corresponding to the cruise thrust command value while generating the yaw moment, the thrust of the 2 cruise rotors 22 can be made to differ sufficiently. However, in the case where the magnitude of the cruise thrust command value is small, when the thrust of the 2 cruise rotors 22 is to be made to differ sufficiently, the cruise thrust becomes excessively large with respect to the cruise thrust command value.

[0087] In the case where the cruise thrust is excessively large with respect to the cruise thrust command value, there are the following 2 points of concern.

[0088] The 1st point of concern is the decrease in energy efficiency. In the case where the yaw moment is generated by the 8 VTOL rotors 18, the output power of each electric motor 32 driving each VTOL rotor 18 is used as energy for the fuselage 12 to act on the yaw moment and for the fuselage 12 to act on the lift thrust. For example, during hovering, the lift thrust needs to be constantly acted on the fuselage 12. Therefore, the output power of each electric motor 32 driving the VTOL rotors 18 is effectively consumed as energy for the fuselage 12 to act on the lift thrust.

[0089] On the other hand, in the case where the yaw moment is generated by the 2 cruise rotors 22, the output power of each electric motor 32 driving each cruise rotor 22 is used as energy for the fuselage 12 to act on the yaw moment and for the fuselage 12 to act on the cruise thrust. For example, as in the case where the fuselage 12 is hovering, the cruise thrust is hardly needed even in the flight state. Nevertheless, the output power of each electric motor 32 driving the cruise rotors 22 is wasted as energy for the fuselage 12 to act on the cruise thrust.

[0090] The 2nd point of concern is the destabilization of the attitude of the fuselage 12 in the pitch direction. In the case where the installation position of each cruise rotor 22 with respect to the fuselage 12 is located farther from the center of gravity G (Gz) than the installation position of each VTOL rotor 18 with respect to the fuselage 12 (Gz), the output power of each electric motor 32 driving each cruise rotor 22 is used as energy for the fuselage 12 to act on the pitch moment. Therefore, the output power of each electric motor 32 driving each cruise rotor 22 is consumed as energy for the fuselage 12 to act on the pitch moment. Figure 1) above or in a position lower than the position thereof, the fuselage 12 generates a pitch moment accompanying generation of the thrust by the respective cruise rotors 22. The larger the cruise thrust, the larger the pitch moment, and the more unstable the posture of the fuselage 12.

[0091] Therefore, in the rotor control device 50 of the present embodiment, the distribution command value calculation section 66 sets the magnitude of the second distribution command value to 0 in a case where the moving average of the yaw moment command value is smaller than the threshold value. The distribution command value calculation section 66 sets the first distribution command value to the yaw moment command value. In this case, the yaw moment is generated by the eight VTOL rotors 18. The two cruise rotors 22 are not used to generate the yaw moment.

[0092] In a case where the moving average of the yaw moment command value is smaller than the threshold value, the required yaw moment is relatively small. Therefore, even by the eight VTOL rotors 18, it is possible to generate a yaw moment of a sufficient magnitude while generating the roll moment and the pitch moment. The two cruise rotors 22 are not used to generate the yaw moment. Accordingly, the rotor control device 50 of the present embodiment can suppress the output power of each electric motor 32 that drives each cruise rotor 22 from becoming excessively large with respect to the cruise thrust command value calculated by the cruise thrust command value calculation section 64. As a result, it is possible to suppress deterioration of the energy efficiency of the aircraft 10. In addition, it is possible to suppress the fuselage 12 from becoming unstable.

[0093] In the rotor control device 50 of the present embodiment, the distribution command value calculation section 66 sets the magnitude of the second distribution command value to be larger than 0 in a case where the moving average of the yaw moment command value is equal to or larger than the threshold value. The distribution command value calculation section 66 sets the first distribution command value to the difference between the yaw moment command value and the second distribution command value. In this case, the yaw moment is generated by the eight VTOL rotors 18, and the yaw moment is generated by the two cruise rotors 22.

[0094] In a case where the moving average of the yaw moment command value is equal to or larger than the threshold value, the required yaw moment is relatively large. Therefore, at times, it is not possible to generate a yaw moment of a sufficient magnitude while generating the roll moment and the pitch moment by only the eight VTOL rotors 18. Therefore, the yaw moment is generated by the eight VTOL rotors 18, and the yaw moment is generated by the two cruise rotors 22. Accordingly, the rotor control device 50 of the present embodiment can act a yaw moment of a sufficient magnitude on the fuselage 12.

[0095] The response speed of a change in the yaw moment generated by the two cruise rotors 22 is lower than the response speed of a change in the yaw moment generated by the eight VTOL rotors 18. Therefore, at times, the yaw moment generated by the two cruise rotors 22 cannot follow a change in the yaw moment command value.

[0096] Therefore, in the rotor control device 50 of the present embodiment, the distribution command value calculation section 66 sets the second distribution command value to the difference between the moving average of the yaw moment command value and the threshold value in the case where the moving average of the yaw moment command value is above the threshold value. The distribution command value calculation section 66 sets the first distribution command value to the difference between the yaw moment command value and the second distribution command value. In this case, the steady component in the yaw moment command value is set to the second distribution command value. The non-steady component in the yaw moment command value is set to the first distribution command value. That is, the component in the yaw moment command value that varies drastically is distributed as the command value for the VTOL rotor 18, and the component that varies gently is distributed as the command value for the cruise rotor 22.

[0097] Accordingly, the yaw moment generated by the two cruise rotors 22 can follow the variation of the second distribution command value. The yaw moment generated by the eight VTOL rotors 18 follows the variation of the yaw moment command value. As a result, the rotor control device 50 of the present embodiment can ensure the magnitude of the yaw moment acting on the fuselage 12 while making the yaw moment acting on the fuselage 12 follow the variation of the yaw moment command value.

[0098] In addition, in the rotor control device 50 of the present embodiment, the distribution command value calculation section 66 reduces the threshold value in the case where a part of the eight VTOL rotors 18 malfunctions. Accordingly, the yaw moment can be generated by the cruise rotors 22 in advance. Therefore, even in the case where a part of the VTOL rotors 18 malfunctions, the rotor control device 50 of the present embodiment can stabilize the attitude of the fuselage 12 in the roll direction and the pitch direction at an early stage.

[0099] In addition, in the rotor control device 50 of the present embodiment, the distribution command value calculation section 66 can reduce the threshold value more as the airspeed of the fuselage 12 is greater. Accordingly, the yaw moment can be generated by the cruise rotors 22 in advance.

[0100] Furthermore, the present application is not limited to the above-described embodiments, and various structures can be employed within the scope of the present application without departing from the gist of the present application.

[0101] In the rotor control device 50 of the first embodiment, the distribution command value calculation section 66 sets the second distribution command value to the difference between the moving average of the yaw moment command value and the threshold value in the case where the moving average of the yaw moment command value is above the threshold value.

[0102] In contrast, the distribution command value calculation section 66 can compare the low-frequency component of the yaw moment command value with the threshold value. In the case where the low-frequency component of the yaw moment command value is above the threshold value, the distribution command value calculation section 66 can set the second distribution command value to the difference between the low-frequency component of the yaw moment command value and the threshold value.

[0103] Further, the distribution command value calculating section 66 can also compare the yaw moment command value with the threshold value. In the case where the yaw moment command value is above the threshold value, the distribution command value calculating section 66 can also cause the second distribution command value to change in stages by a predetermined change amount, depending on the difference between the yaw moment command value and the threshold value. Further, in the case where the yaw moment command value is above the threshold value, the distribution command value calculating section 66 can also set the second distribution command value to the difference between the yaw moment command value and the threshold value.

[0104] 〔Invention obtainable according to the embodiment〕

[0105] The invention obtainable according to the above-described embodiment will be described below.

[0106] A posture control device (50) that performs posture control of a fuselage (12) of an aircraft (10) having a plurality of vertical rotors (18) that generate thrust in the vertical direction and a plurality of horizontal rotors (22) that generate thrust in the horizontal direction, the posture control device having a yaw moment command value calculating section (62) that calculates a command value of a yaw moment acting on the fuselage, a distribution command value calculating section (66) that calculates a first distribution command value and a second distribution command value depending on the command value of the yaw moment, a vertical rotor control section (72) that controls each of the vertical rotors depending on the first distribution command value, and a horizontal rotor control section (74) that controls each of the horizontal rotors depending on the second distribution command value, the distribution command value calculating section setting the first distribution command value to the difference between the command value of the yaw moment and the second distribution command value, the distribution command value calculating section setting the magnitude of the second distribution command value to 0 in the case where the command value of the yaw moment is less than a threshold value, and the distribution command value calculating section setting the magnitude of the second distribution command value to greater than 0 in the case where the command value of the yaw moment is above the threshold value. Thereby, it is possible to stabilize the posture of the fuselage in the yaw direction also at an early stage while suppressing the cruise thrust from becoming excessively large with respect to the cruise thrust command value.

[0107] In the attitude control device described above, the distribution command value calculation section can set the magnitude of the second distribution command value to 0 in the case where the yaw moment command value is smaller than the threshold value, and set the second distribution command value to a value corresponding to the low-frequency component of the yaw moment command value in the case where the yaw moment command value is equal to or greater than the threshold value. Thereby, it is possible to ensure the magnitude of the yaw moment acting on the fuselage while making the yaw moment acting on the fuselage follow the change in the command value.

[0108] In the attitude control device described above, the distribution command value calculation section can make the threshold value variable. Thereby, it is possible to stabilize the attitude of the fuselage early in the roll direction and the pitch direction.

[0109] In the attitude control device described above, the distribution command value calculation section can make the threshold value variable in accordance with the number of vertical rotors that have failed. Thereby, it is possible to stabilize the attitude of the fuselage early in the roll direction and the pitch direction.

Claims

1. A posture control device (50) that performs posture control of a fuselage (12) of an aircraft (10) having a plurality of vertical rotors (18) that generate thrust in a vertical direction and a plurality of horizontal rotors (22) that generate thrust in a horizontal direction, characterized by, having a yaw moment command value calculation section (62), an allocation command value calculation section (66), a vertical rotor control section (72), and a horizontal rotor control section (74), wherein, the yaw moment command value calculation section (62) calculates a command value of a yaw moment acting on the fuselage, the allocation command value calculation section (66) calculates a first allocation command value and a second allocation command value from the command value of the yaw moment, the vertical rotor control section (72) controls each of the vertical rotors from the first allocation command value, the horizontal rotor control section (74) controls each of the horizontal rotors from the second allocation command value, the allocation command value calculation section sets the first allocation command value as a difference between the command value of the yaw moment and the second allocation command value, in a case where the command value of the yaw moment is smaller than a threshold value, the allocation command value calculation section sets a magnitude of the second allocation command value as 0, in a case where the command value of the yaw moment is larger than the threshold value, the allocation command value calculation section sets the magnitude of the second allocation command value as larger than 0.

2. The posture control device according to claim 1, characterized in that, in a case where the command value of the yaw moment is smaller than the threshold value, the allocation command value calculation section sets the magnitude of the second allocation command value as 0, in a case where the command value of the yaw moment is larger than the threshold value, the allocation command value calculation section sets the second allocation command value as a value corresponding to a low frequency component of the command value of the yaw moment.

3. The posture control device according to claim 1 or 2, characterized in that, the allocation command value calculation section makes the threshold value variable.

4. The posture control device according to claim 3, characterized in that, the allocation command value calculation section makes the threshold value variable in accordance with a number of the vertical rotors that have failed. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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