Control device for flying object

Abstract

The present invention provides a control device for an aircraft that can suppress battery degradation while maintaining a flight state. The control device (1) for the aircraft includes a generator (11), a drive source (12), a battery (13), an electric motor (3), a rotor (4), a battery state detection unit (5), a variable pitch mechanism (6), and a pitch change control unit (7). The electric motor (3) is driven by electric power supplied from at least one of the generator (11) and the battery (13). The rotor (4) is driven by the electric motor (3). The battery state detection unit (5) detects the charge state of the battery (13). The variable pitch mechanism (6) changes the pitch of the rotor (4). The pitch change control unit (7) determines whether to change the pitch of the rotor (4) based on the battery charge rate detected by the battery state detection unit (5).

Description

Technical Field

[0001] The present invention relates to a control device for a flying object. Background Art

[0002] Conventionally, there are known flying vehicles that include a driving source such as a gas turbine engine and a battery for storing electric power generated by the driving source. Various technologies have been proposed for suppressing degradation of the battery due to overcharging or the like in these flying vehicles.

[0003] For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-32906) discloses a power supply device comprising a fuel cell and a battery that stores excess power from the fuel cell and discharges it to the outside when the fuel cell output is insufficient. The power supply device also includes a power consumption mechanism that consumes power. When the power generated by the fuel cell is greater than the load power and the battery is fully charged, the power consumption mechanism consumes the excess power.

[0004] According to the technology described in Patent Document 1, overcharging of the battery can be suppressed by operating a portion of the mechanisms (power consumption mechanisms) in the entire system to consume excess power. Summary of the Invention

[0005] Problems to be solved by the invention

[0006] However, there are known aircraft that include a generator driven by a drive source, a battery that stores excess power from the generator, and a propeller (rotating wing) driven by the power from the generator or battery, with propellers driving the propellers to generate propulsion. These aircraft require the consumption of excess power during flight. Therefore, for example, it is necessary to maintain the aircraft's flight while operating some mechanisms within the overall system.

[0007] Therefore, an object of the present invention is to provide a control device for an aerial vehicle that can suppress degradation of a battery while maintaining the aerial vehicle.

[0008] Solutions to Problems

[0009] In order to solve the above-mentioned problems, the control device for an aircraft according to the present invention adopts the following structure.

[0010] (1) A control device for an aircraft according to one embodiment of the present invention comprises: a power unit including a generator, a driving source for driving the generator, and a battery for storing electric power generated by the generator; an electric motor driven by electric power supplied from at least one of the generator and the battery; a rotor driven by the electric motor; a battery state detection unit for detecting a charge state of the battery; a variable pitch mechanism for changing the pitch of the rotor; and a pitch change control unit for determining whether to change the pitch of the rotor based on a charge rate of the battery detected by the battery state detection unit.

[0011] (2) In the control device for an aircraft according to the above-mentioned aspect (1), the pitch change control unit may calculate a rate of change of the pitch of the rotor based on an amount of electric power supplied from the power unit.

[0012] (3) In the control device for the flying object according to the above-mentioned scheme (1) or (2), the pitch change control unit may change the pitch when a request for a reduction in the required output is made from the flight controller of the flying object to the power unit.

[0013] Effects of the Invention

[0014] According to the scheme (1), for example, when the charge rate of the battery detected by the battery state detection unit becomes greater than a predetermined value, the pitch of the rotor is changed by the pitch change control unit. Specifically, the pitch change control unit changes the pitch of the rotor in a manner that increases the load on the electric motor that rotates the rotor. As a result, the efficiency of the rotor is reduced, and the power consumption of the rotor can be increased while maintaining the flight state. Therefore, the consumption of the power of the battery or the power generated by the generator can be increased, and the excess power can be consumed efficiently. As a result, the deterioration of the battery caused by overcharging can be suppressed.

[0015] Therefore, it is possible to provide a control device for an aerial vehicle that can suppress degradation of a battery while maintaining a flying state.

[0016] Furthermore, for example, if the battery charge rate is low, the rotor pitch is varied to reduce the load on the electric motor. This allows the power generated by the generator during operation of the drive source to be allocated to charge the battery. This reduces the load on the drive source and minimizes degradation in fuel consumption.

[0017] According to the embodiment (2), the rate of change of the rotor's pitch is determined based on the amount of power supplied from the power unit, so the rate of change of the pitch can be set according to the amount of power to be consumed. This can prevent excessive loads on the rotor and the variable pitch mechanism.

[0018] According to the scheme of (3), the pitch is changed when a reduction in the required output is requested. Here, there are many cases where the drive source cannot respond to the request from the flight controller in a short time. That is, there is a case where power is supplied (charged) to the battery during the period from when the flight controller requests a reduction in the output to when the output of the drive source is actually reduced. Therefore, especially when a reduction in the required output is requested and the battery is fully charged, the condition for consuming excess power becomes stricter than when an increase in the required output is requested. According to the control device for the flying object of the present invention, the pitch is changed when a reduction in the required output is requested, so that the excess power can be consumed more efficiently by the power consumed by the pitch change and the increase in the load on the electric motor caused by the increase in the resistance of the rotor accompanying the pitch change. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a circuit configuration diagram of a control device for an aircraft according to an embodiment.

[0020] Figure 2 This is a graph showing the relationship between the circumferential velocity of the rotor and the lift due to the difference in pitch angle.

[0021] Figure 3 This is a graph showing the relationship between pitch and the output of the power unit.

[0022] Figure 4 This is a flowchart showing the flow of control performed by the control device according to the embodiment.

[0023] Description of Reference Numerals

[0024] 1. Control device of flying object

[0025] 2 Power Unit

[0026] 3 Electric motors

[0027] 4 Rotary Wings

[0028] 5. Battery status detection unit

[0029] 6 Variable pitch mechanism

[0030] 7 Pitch change control unit

[0031] 11 Generator

[0032] 12 Gas turbine engine (drive source)

[0033] 13. Battery

[0034] 20 flight controllers. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] (Control device for flying object)

[0037] Figure 1 It is a circuit configuration diagram of a control device 1 for an aircraft according to an embodiment (hereinafter, sometimes simply referred to as a control device 1 ).

[0038] The control device 1 is mounted on a body of a flying object (not shown), such as an aircraft, for example. The control device 1 constitutes a hybrid propulsion system that propels the flying object using a plurality of electric motors 3 driven by electric power generated by a generator 11 (described in detail later).

[0039] The control device 1 includes a power unit 2 , an electric motor 3 , a rotor 4 , a battery state detection unit 5 , a variable pitch mechanism 6 , and a pitch change control unit 7 .

[0040] (Power Unit)

[0041] The power unit 2 includes a driving source 12, a generator 11, and a battery 13. The power unit 2 controls the driving of the driving source 12, the generator 11, and the battery 13 based on a signal from a flight controller 20, for example.

[0042] The drive source 12 is, for example, a gas turbine engine. The gas turbine engine 12 includes a compressor and a turbine. The compressor compresses intake air drawn in through ventilation holes (not shown) provided in the aircraft's fuselage. The turbine is connected to the compressor via a rotating shaft and rotates integrally with the compressor. It should be noted that while the gas turbine engine 12 is described as an example of a drive source in this embodiment, the invention is not limited thereto. The drive source 12 may be a power device for operating the generator 11 to generate electricity, and may also be, for example, a fuel cell.

[0043] The generator 11 is connected to a gas turbine engine 12. A transmission mechanism or the like may be provided between the generator 11 and the gas turbine engine 12. The generator 11 generates electricity (AC power) by driving the turbine. The AC power generated by the generator 11 is converted into DC power by a converter in a power drive unit (PDU) and stored in a battery 13.

[0044] The battery 13 stores the amount of electricity generated by the generator 11 driven by the gas turbine engine 12 that is not consumed by the electric motor 3. The electricity stored in the battery 13 can be used to drive the electric motor 3. Specifically, when the power generated by the converter exceeds the power consumed by the inverter, the battery 13 absorbs the power generated by the generator 11 and charges. On the other hand, when the power generated by the converter falls below the power consumed by the inverter, the battery 13 discharges to compensate for the power shortfall.

[0045] (Electric Motor)

[0046] The electric motor 3 is, for example, a brushless DC motor. It should be noted that the electric motor 3 may also include an auxiliary motor for posture maintenance or horizontal propulsion, which is not shown in the figure. The electric motor 3 is connected to the generator 11 and the battery 13 of the power unit 2, respectively. At least one of the discharged power from the battery 13 and the power from the generator 11 is supplied to the electric motor 3. That is, the supply of power from the generator 11 to the electric motor 3 and the supply of power from the battery 13 to the electric motor 3 are appropriately switched. Specifically, the generator 11, the battery 13 and the electric motor 3 are controlled in a manner such that at least any one of the following states (i) and (iii) is achieved.

[0047] (i) A state in which electric power is supplied from the generator 11 to the electric motor 3 and the supply of electric power from the battery 13 to the electric motor 3 is stopped.

[0048] (ii) A state in which the supply of electric power from the generator 11 to the electric motor 3 is stopped and electric power is supplied from the battery 13 to the electric motor 3 .

[0049] (iii) A state where electric power is supplied to the electric motor 3 from both the generator 11 and the battery 13. In this case, the ratio of the amount of electric power supplied from the generator 11 or the battery 13 can be changed as needed.

[0050] (rotary wing)

[0051] The rotor blades 4 are connected to the electric motor 3. A propeller shaft (not shown) is provided between the electric motor 3 and the rotor blades 4 to mechanically connect the electric motor 3 and the rotor blades 4. The electric motor 3 rotates in response to a control signal, thereby rotating the rotor blades 4. The control signal is a signal used to control the aircraft based on the pilot's operation or instructions during automatic control. The pitch of the rotor blades 4 is configured to be variable. In other words, the aircraft of this embodiment is a variable pitch aircraft.

[0052] As described above, the aircraft is configured such that the electric motor 3 is driven primarily by the electric power generated by the generator 11 driven by the gas turbine engine 12, and thrust is generated by the rotor blades 4 rotated by the electric motor 3. The electric power generated by the generator 11 can be stored in the battery 13, and the electric power from the battery 13 can be used as the electric power for driving the electric motor 3 as needed.

[0053] (Battery status detection unit)

[0054] The battery state detection unit 5 detects the state of charge of the battery 13. For example, the battery state detection unit 5 detects the battery charge rate (SOC), which indicates the current charge level of the battery 13 relative to the total capacity of the battery 13, as the state of charge of the battery 13. Furthermore, the battery state detection unit 5 may also detect, for example, the charging rate during charging and the discharging rate during discharging.

[0055] (Variable pitch mechanism)

[0056] The variable pitch mechanism 6 changes the pitch of the rotor blade 4. The variable pitch mechanism 6 is mounted, for example, near the central axis of the rotor blade 4. Based on a signal from a pitch change control unit 7 (described in detail later), the variable pitch mechanism 6 changes the pitch of the rotor blade 4 to a predetermined pitch angle. In this embodiment, the variable pitch mechanism 6 can change the pitch of the rotor blade 4 between 0% (rotor blade 4 parallel to the ground) and 90% (rotor blade 4 perpendicular to the ground).

[0057] (Pitch change control unit)

[0058] Pitch change control unit 7 determines whether to change the pitch of rotor 4 based on the battery SOC detected by battery state detection unit 5. When changing the pitch, pitch change control unit 7 calculates the rate of change of pitch based on the amount of power supplied by power unit 2 and outputs the calculated result to variable pitch mechanism 6. This controls the pitch of rotor 4 to a desired pitch angle.

[0059] In this embodiment, the pitch change control unit 7 causes the variable pitch mechanism 6 to change its pitch when a request for a reduction in required output is made from the flight controller 20 of the aircraft to the power unit 2 and when predetermined conditions are met. Specifically, the pitch change control unit 7 changes the pitch when a request for a reduction in required output is made, the output reduction in the gas turbine engine 12 is insufficient, and the battery SOC is above a predetermined value. On the other hand, the pitch change control unit 7 does not change the pitch when a request for a reduction in required output is made but the output reduction in the gas turbine engine 12 is sufficient (allowable solely by the response of the gas turbine engine 12), or when a request for a reduction in required output is made but the battery SOC is below a predetermined value.

[0060] In this embodiment, when a pitch change is requested to reduce the required output, the pitch change control unit 7 first calculates excess power. The excess power is the value obtained by subtracting the total power of the rotor 4 drive power and the power of the battery 13 from the power generated by the generator 11. The pitch change control unit 7 then changes the pitch of the rotor 4 so that the target pitch angle is smaller than the current pitch angle.

[0061] Figure 2 Graph 1 is a graph showing the relationship between the circumferential velocity Vr of the rotor 4 and the lift Lf due to the difference in pitch angle. Figure 2 Graph G1 shows a pitch angle of 0% (rotor 4 is parallel to the ground). Graph G2 shows a pitch angle of 20%. Graph G3 shows a pitch angle of 40%. Graph G4 shows a pitch angle of 60%. The horizontal axis of the graph represents the circumferential velocity Vr of rotor 4. The vertical axis of the graph represents the lift force Lf of the aircraft. Graph G5 represents the target lift force of the aircraft.

[0062] like Figure 2 As shown in graph G1, when the pitch angle is 0%, the lift is zero regardless of the circumferential velocity Vr. As shown in graphs G2 to G4, when the pitch angle is 20%, 40%, and 60%, the lift Lf increases as the circumferential velocity Vr of the rotor 4 increases. When comparing graphs G2 to G4, the larger the pitch angle, the smaller the circumferential velocity Vr required to obtain the target lift G5. In other words, the larger the pitch angle, the less energy is required to obtain the required lift. On the other hand, if the pitch angle is reduced (for example, 40%: graph G3), more energy is consumed to obtain the same lift as when the pitch angle is larger (for example, 60%: graph G6).

[0063] Figure 3 This is a graph showing the relationship between pitch P and power unit 2 output (OPU). The horizontal axis of the graph represents the pitch P of rotor 4. The vertical axis of the graph represents power unit 2 output (OPU). Power unit 2 output (OPU) is the sum of the output from generator 11 and the output from battery 13. Graph G6 shows the target lift of the flying object.

[0064] like Figure 3 As shown, in normal operation (in this embodiment, before pitch change), the aircraft moves at point A1. At point A1, the pitch P of the rotor 4 is set to the first pitch P1, and the output OPU of the power unit 2 is set to the first output PWR1.

[0065] When the pitch change control unit 7 determines to change the pitch of the rotary wing 4, the pitch change control unit 7 changes the pitch P and the output OPU from the power unit 2 in such a manner that the flying object operates at point A2. At point A2, the pitch P of the rotary wing 4 is set to the second pitch P2, and the output OPU of the power unit 2 is set to the second output PWR2. The second pitch P2 is a pitch angle smaller than the first pitch P1 (P2 < P1). The second output PWR2 is larger than the first output PWR1 (PWR2 > PWR1).

[0066] By changing the pitch P of the rotary wing 4 from the first pitch P1 to the second pitch P2 in this way, the electric power OPU from the power unit 2 required to obtain the target lift increases by an amount corresponding to the electric power amount D. Therefore, when a reduction in the required output is demanded, the output reduction in the gas turbine engine 12 is insufficient, and the battery SOC is above the specified value, the pitch change control unit 7 changes from the first pitch P1 to the second pitch P2, so that an amount of excess power corresponding to the electric power amount D can be consumed compared to the normal time. Thus, overcharging of the battery 13 is suppressed.

[0067] (Flow of control of the control device of the flying object)

[0068] Figure 4 is a flowchart showing the flow of control performed by the control device 1 of the embodiment. Hereinafter, Figure 4 is used to explain the flow of control of the control device 1 in more detail. Regarding each reference numeral, refer to Figure 1 together.

[0069] First, the control device 1 determines whether the generator 11 is generating electricity (step S01) by obtaining information on the gas turbine engine 12 (drive source) and the generator 11. When the generator 11 is not generating electricity (No in step S01), the pitch change control unit 7 does not change the pitch of the rotary wing 4, and the process ends (step S07).

[0070] When it is determined that the generator 11 is generating electricity (Yes in step S01), the control device 1 determines whether the generated power can be charged into the battery 13 (step S03). In step S03, the control device 1 determines whether the battery 13 can be charged, for example, based on the determination result of whether the current battery SOC is above a preset specified value. For example, when the current battery SOC is above the specified value, the control device 1 determines that the battery 13 cannot be charged. On the other hand, for example, when the current battery SOC is less than the specified value, the control device 1 determines that the battery 13 can be charged.

[0071] If it is determined that the generated power can be charged into the battery 13 (YES in step S03 ), the control device 1 starts charging the battery 13 (step S05 ). The process then proceeds to step S07 and ends without changing the pitch.

[0072] On the other hand, if it is determined that the generated power cannot be charged into the battery 13 (No in step S03), the pitch change control unit 7 calculates the excess power based on the power generated by the generator 11, the drive power of the rotor 4, and the power obtained from the battery 13 (step S11). Next, the pitch change control unit 7 calculates the rate of change of the pitch based on the calculated excess power (step S13). The rate of change of the pitch is the rate of change from the current pitch to the target pitch. The target pitch is calculated, for example, by multiplying the reference pitch by a correction factor of 1 or less. The correction factor can also be a value that varies depending on the amount of excess power. For example, the correction factor can be set so that the value of the correction factor gradually decreases as the excess power increases. The target pitch thus calculated is the pitch required to consume the calculated excess power by increasing the load on the electric motor 3.

[0073] Next, pitch change control unit 7 outputs a signal to variable pitch mechanism 6 to achieve the calculated rate of change of pitch. Based on the signal from pitch change control unit 7, variable pitch mechanism 6 changes the pitch of rotor 4 to achieve the target pitch (step S15). When the pitch change is complete, the process ends. This concludes the process in this flowchart.

[0074] (Action, effect)

[0075] Next, the operation and effects of the above-mentioned flying object control device 1 will be described.

[0076] The aircraft control device 1 of this embodiment includes a variable pitch mechanism 6 that changes the pitch of the rotor 4, and a pitch change control unit 7 that determines whether to change the pitch of the rotor 4 based on the charge rate of the battery 13 detected by the battery state detection unit 5. Thus, for example, when the charge rate of the battery 13 detected by the battery state detection unit 5 exceeds a predetermined value, the pitch change control unit 7 changes the pitch of the rotor 4. Specifically, the pitch change control unit 7 changes the pitch of the rotor 4 to increase the load on the electric motor 3 that rotates the rotor 4. This reduces the efficiency of the rotor 4, thereby increasing the power consumption of the rotor 4 while maintaining flight. Consequently, the power consumption of the battery 13 or the power generated by the generator 11 can be increased, effectively dissipating excess power. As a result, deterioration of the battery 13 caused by overcharging can be suppressed. Therefore, a flight control device 1 can be provided that can maintain flight while suppressing deterioration of the battery 13.

[0077] Pitch change control unit 7 calculates the rate of change in the pitch of rotor blade 4 based on the amount of power supplied from power unit 2. This allows the rate of change in pitch to be set according to the desired amount of power consumed. This prevents excessive loads on rotor blade 4 and variable pitch mechanism 6.

[0078] The pitch change control unit 7 changes the pitch when a reduction in the required output is requested. Here, there are many cases where the gas turbine engine 12 (drive source) cannot respond to the request from the flight controller 20 in a short time. That is, there is a case where power is supplied (charged) to the battery 13 during the period from when the flight controller 20 requests a reduction in output to when the output of the gas turbine engine 12 is actually reduced. Therefore, especially when a reduction in the required output is requested and the battery 13 is fully charged, the condition for consuming excess power becomes stricter than when an increase in the required output is requested. According to the control device 1 of the flying object of the present invention, a pitch change is performed when a reduction in the required output is requested. Therefore, the excess power can be consumed more efficiently by the power consumed by the pitch change and the increase in the load on the electric motor 3 caused by the increase in the resistance of the rotor 4 accompanying the pitch change.

[0079] It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0080] For example, in the above-described embodiment, pitch changes are performed when a reduction in required output is requested and the battery SOC is above a predetermined value, but the present invention is not limited to this. For example, when the SOC of the battery 13 falls below a predetermined lower limit, the pitch of the rotor 4 may be changed (increased in pitch angle) to reduce the load on the electric motor 3. This allows the electric power generated by the generator 11 by the operation of the gas turbine engine 12 to be allocated as charging power for the battery 13. This reduces the load on the gas turbine engine 12 and suppresses degradation in fuel efficiency.

[0081] A plurality of gas turbine engines 12 and generators 11 may be provided.

[0082] Although the example using the gas turbine engine 12 as the driving source has been described, the present invention is not limited thereto. For example, a fuel cell or the like may be used as the driving source 12 .

[0083] In addition, within the scope not departing from the gist of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

Claims

1. A control device for a flying object, wherein: The control device of the flying object comprises: a power unit including a generator, a driving source for driving the generator, and a battery for storing electric power generated by the generator; an electric motor driven by electric power supplied from at least one of the generator and the battery; a rotary wing driven by the electric motor; a battery state detection unit configured to detect a charge state of the battery; a variable pitch mechanism for changing the pitch of the rotor; as well as A pitch change control unit determines whether to change the pitch of the rotor based on the charge rate of the battery detected by the battery state detection unit.

2. The control device for an aircraft according to claim 1, wherein: The pitch change control unit calculates a rate of change of the pitch of the rotor based on an amount of electric power supplied from the power unit.

3. The control device for an aircraft according to claim 1 or 2, wherein: The pitch change control unit changes the pitch when a request for a reduction in required output is made to the power unit from a flight controller of the flying object.

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