JP7512242B2 - Multicopter - Google Patents

Description

The technology disclosed in this specification relates to a multicopter that has an engine-driven generator and a rechargeable battery, and flies by supplying power to a motor to rotate multiple rotors.

A conventional example of this type of technology is the multicopter described in Patent Document 1 below. In addition to multiple rotors, a motor, and a battery, this multicopter also includes an engine generator unit that generates power, and a control unit that controls the multicopter. The engine generator unit includes an engine and a generator driven by the engine. The generator generates power to be supplied to the motor or to charge the battery. The control unit controls the engine to control power generation by the generator, controls the supply of power from the generator to the motor and the charging of power from the generator to the battery, controls the discharge of power from the battery to the motor, and controls the flight of the multicopter.

JP 2020-138594 A

In a multicopter equipped with an engine-driven generator and a rechargeable battery, even if the power generated by the generator is supplied to the motor during takeoff flight, the power generated by the generator may not be sufficient to meet the flight power required for takeoff, and most of the flight power may have to be supplemented with battery power discharged from the battery. This requires a large-capacity battery, which results in a larger and heavier battery. On the other hand, during landing flight, the power generated by the generator is supplied to the motor, but the flight power required for landing may be less than the generated power, and the surplus generated power must be charged into the battery. This also requires a large-capacity battery, which results in a larger and heavier battery. As a result, the weight of the multicopter increases, the amount of fuel that can be carried by the engine decreases, and the multicopter's cruising range and payload performance decrease.

This disclosed technology has been made in consideration of the above circumstances, and its first objective is to provide a multicopter equipped with an engine-driven generator and a chargeable/dischargeable battery, in which the battery power can be reduced by reducing the battery power of the generator's power that satisfies the flight power required for takeoff and the battery power of the battery. The second objective of this disclosed technology is to provide a multicopter that, in addition to the first objective, can also provide a multicopter in which the battery can be reduced in size and weight by reducing the surplus of power that is charged into the battery among the power generated by the generator that satisfies the flight power required for landing of the multicopter.

In order to achieve the above object, the technology described in claim 1 includes a plurality of rotors, a motor for rotating and driving each rotor, a battery configured to be able to charge and discharge the power supplied to the motor, a generator for generating power supplied to the motor and power charged to the battery, an engine for driving the generator, and a control means for controlling the operation of the engine, the supply of power from the generator to the motor, the charging of the battery from the generator, and the discharging of the battery from the motor. The technology further includes an acquisition means for acquiring a flight response speed required for the multicopter in a multicopter that flies by supplying power to the motor to rotate each rotor, and the control means is configured to supply generated power from the generator to the motor in order to satisfy the flight power required for the takeoff of the multicopter, and to discharge battery power from the battery to the motor in order to make up for the power that is insufficient with the generated power alone. The control means controls the engine to change the output response speed of the generator in accordance with the flight response speed acquired by the acquisition means when the multicopter takes off, and controls the generated current flowing from the generator to the motor.

According to the configuration of the above technology, the multicopter flies by supplying power to the motor to rotate each rotor. Here, the control means controls the operation of the engine, the supply of power from the generator to the motor, charging from the generator to the battery, and discharging from the battery to the motor. The control means supplies generated power from the generator to the motor in order to satisfy the flight power required for takeoff of the multicopter, and discharges battery power from the battery to the motor in order to make up for the power that is insufficient with the generated power alone. The control means also controls the engine to change the output response speed of the generator in accordance with the flight response speed acquired by the acquisition means when the multicopter takes off, and controls the generated current flowing from the generator to the motor. Therefore, in the multicopter, in order to satisfy the flight power required for takeoff, the output response speed of the generator is changed in accordance with the acquired flight response speed, and the generated current flowing from the generator to the motor is controlled, so that the battery power borne by the battery to make up for the power that is insufficient with the generated power alone of the generator is reduced.

In order to achieve the above object, the technology described in claim 2 is the technology described in claim 1, in which the control means is configured to supply generated power from the generator to the motor and charge the battery with the surplus generated power in order to satisfy the flight power required for the landing of the multicopter, and the control means controls the engine to change the output response speed of the generator in accordance with the flight response speed acquired by the acquisition means when the multicopter lands, and controls the generated current flowing from the generator to the motor.

According to the configuration of the above technology, in addition to the action of the technology described in claim 1, the control means supplies generated power from the generator to the motor and charges the battery with the surplus generated power in order to satisfy the flight power required for landing of the multicopter. The control means also controls the engine to change the output response speed of the generator in accordance with the flight response speed acquired by the acquisition means when the multicopter lands, and controls the generated current flowing from the generator to the motor. Therefore, in the multicopter, in order to satisfy the flight power required for landing, the output response speed of the generator changes in accordance with the acquired flight response speed, and the generated current flowing from the generator to the motor is controlled, so that the surplus power of the generator that is not supplied to the motor is reduced, and the surplus power to be charged to the battery is reduced.

To achieve the above object, the technology described in claim 3 is the technology described in claim 1 or 2, further comprising an output adjustment means for adjusting the output of the engine, and the control means controls the output adjustment means to adjust the output of the engine in accordance with the acquired flight response speed, thereby changing the output response speed of the generator.

According to the configuration of the above technology, the control means controls the output adjustment means as described above, thereby achieving the same effect as the technology described in claim 1 or 2.

To achieve the above object, the technology described in claim 4 is the technology described in claim 3, in which the control means controls the output adjustment means so that the faster the acquired flight response speed is, the faster the output response speed of the generator becomes, and the slower the acquired flight response speed is, the slower the output response speed of the generator becomes.

According to the configuration of the above technology, the control means controls the output adjustment means as described above, thereby achieving the same effect as the technology described in claim 3.

According to the technology described in claim 1, in a multicopter equipped with an engine-driven generator and a chargeable and dischargeable battery, the battery power can be reduced, between the generator's generated power that satisfies the flight power required for takeoff and the battery's battery power, thereby making the battery smaller and lighter.

According to the technology described in claim 2, in addition to the effect of the technology described in claim 1, it is possible to reduce the surplus of the generated power of the generator that satisfies the flight power required for the landing of the multicopter and is charged into the battery, thereby making it possible to reduce the size and weight of the battery.

The technique described in claim 3 can achieve the same effect as the technique described in claim 1 or 2.

The technique described in claim 4 can achieve the same effect as the technique described in claim 3.

FIG. 1 is a perspective view showing an external appearance of a multicopter in a first embodiment. FIG. 2 is a block diagram showing the configuration of a multicopter in the first embodiment. 1 is a schematic configuration diagram showing a generator engine system and some of its associated devices in a first embodiment; 10 is a graph showing the relationship between the engine speed and power generation current at the time of takeoff of the multicopter in the first embodiment, and an equal fuel consumption rate line, an equal output line, an engine full-throttle performance line, an equal voltage line, and an operating line. 5 is a flowchart showing the contents of takeoff output control in the first embodiment. 4 is a response time map that is referred to in order to determine a response time according to a takeoff response speed in the first embodiment. 5 is a graph showing only the relationship between the engine speed and the operating line of the generated current in FIG. 4 according to the first embodiment; 5 is a time chart showing the behavior of various parameters related to takeoff output control in a case where the multicopter takes off rapidly in the first embodiment. 5 is a time chart showing the behavior of various parameters related to takeoff output control in the case where the multicopter takes off slowly in the first embodiment. 10 is a time chart showing the behavior of various parameters when the generator has a slow response, as a comparative example. 5 is a graph similar to FIG. 4 showing the relationship between the engine speed and power generation current when the multicopter lands, the iso-fuel consumption rate line, the iso-output line, the engine full-throttle performance line, the iso-voltage line, and the operating line in the second embodiment. 10 is a flowchart showing the details of landing output control in the second embodiment. 12 is a graph showing only the relationship between the engine speed and the operating line of the generated current in FIG. 11 according to the second embodiment; 13 is a time chart showing the behavior of various parameters related to landing output control in a case where the multicopter rapidly lands in the second embodiment. 13 is a time chart showing the behavior of various parameters related to landing output control in a case where the multicopter lands slowly in the second embodiment. FIG. 11 is a time chart showing the behavior of various parameters when the generator has a slow response during landing, as a comparative example.

The following describes an embodiment of a multicopter that embodies this disclosed technology.

First Embodiment
First, the first embodiment will be described in detail with reference to the drawings.

[About the multicopter configuration]
Fig. 1 is a perspective view showing the appearance of a multicopter 1 according to this embodiment. Fig. 2 is a block diagram showing the configuration of the multicopter 1. The configuration of the multicopter 1 will be described in detail below with reference to Figs. 1 and 2.

A multicopter is a type of helicopter, a rotary wing aircraft equipped with three or more rotors. The multicopter 1 of this embodiment includes an airframe 11 and an engine generator unit 12. The airframe 11 includes a plurality of arms 21 (four in this embodiment) with bifurcated tips, an arm base 22 that radially supports the plurality of arms 21 in a cantilevered manner, an airframe base 23 that supports the arm base 22, a plurality of motors 24 (eight in this embodiment) provided at the tip of each arm 21, and a plurality of rotors 25 (eight in this embodiment) that are rotated by each motor 24. This multicopter 1 flies by simultaneously rotating the plurality of rotors 25 by the corresponding motors 24.

The arm base 22 is provided on the aircraft base 23. Inside the arm base 22, a battery 31, a fuel tank 32, a main controller 33, a flight controller 34, a power control unit 35, an electric speed controller 36, etc. are provided. The arm base 22 also has an imaging unit 37 that captures or records images of the outside world. The imaging unit 37 includes a camera, a recording memory, etc.

The engine generator unit 12 is suspended below the aircraft base 23. The engine generator unit 12 includes a power generation engine system 15 (including an engine 41) described below, and a generator 42 that is driven by the engine 41 to generate electricity.

Each motor 24 is electrically connected to the generator 42 via an electric speed controller 36 (including an inverter (not shown)) and a power control unit 35. This connection allows the power generated by the generator 42 to be supplied to the motor 24 via the power control unit 35 and the electric speed controller 36.

The battery 31 is composed of a secondary battery capable of charging and discharging power. The battery 31 is electrically connected to the generator 42 via the power control unit 35, and is configured to charge the battery 31 with power generated by the generator 42. The battery 31 is electrically connected to each motor 24 via the power control unit 35 and the electric speed controller 36, and is configured to supply the power discharged from the battery 31 to each motor 24. The battery 31 is provided with sensors (not shown) that respectively detect the current and voltage of the battery 31, and these sensors are configured to send electrical signals related to the detection results to the main controller 33.

The fuel tank 32 stores fuel (e.g., gasoline). This fuel is used to drive the engine 41. A level sensor (not shown) provided in the fuel tank 32 sends an electrical signal regarding the remaining amount of fuel to the main controller 33.

The main controller 33 is configured as a small computer and controls all operations related to the multicopter 1. The main controller 33 includes a wind direction acquisition unit 45, a rotation control unit 46, a wind power acquisition unit 47, a machine control unit 48, and an engine control unit 50. Here, for example, the engine control unit 50 controls the operation of the engine 41 in order to control power generation in the generator 42. The main controller 33 controls the operation of the engine 41, the supply of power from the generator 42 to each motor 24, charging the battery 31 from the generator 42, and discharging from the battery 31 to each motor 24. The main controller 33 corresponds to an example of a control means in this disclosed technology.

The flight controller 34 is a device that controls the flight of the multicopter 1. This flight controller 34 sends electrical signals to the main controller 33 and the electric speed controller 36 to instruct the thrust related to the flight of the multicopter 1, while receiving electrical signals related to the charge state of the battery 31 from the main controller 33. The flight controller 34 receives electrical signals related to the pilot's operation commands from the remote control 30, which will be described later, and electrical signals related to the detection results from the various sensors 28, which will be described later.

The power control unit 35 is a device that controls the power supplied to each motor 24. This power control unit 35 receives power generated by the generator 42, supplies and receives power to and from the battery 31, and supplies power to the electric speed controller 36. The power control unit 35 receives an electrical signal related to a charge/discharge switching command from the main controller 33. The power control unit 35 also sends an electrical signal related to the current of the battery 31 and an electrical signal related to the current of the generator 42 to the main controller 33.

The electric speed controller 36 is a device that controls the rotation speed of each motor 24. This electric speed controller 36 supplies the power supplied via the power control unit 35 to each motor 24 as drive power. The electric speed controller 36 receives an electrical signal related to a thrust command from the flight controller 34.

The engine generator unit 12 includes a part of the generator engine system 15, including the engine 41, and a generator 42. The engine 41 is the driving source for the generator 42, and in this embodiment, is configured as a small reciprocating gasoline engine. That is, the engine 41 drives the generator 42 so that the generator 42 generates electricity to be supplied to each motor 24 or the battery 31. In addition, various components 57, 60, and 62 that configure the generator engine system 15, which will be described later, receive electrical signals related to engine control commands for the purpose of generating electricity from the engine control unit 50 of the main controller 33.

In this embodiment, the multicopter 1 includes various sensors 28 and a remote control 30. The various sensors 28 include sensors for detecting the altitude, attitude, latitude, longitude, acceleration, and obstacles of the multicopter 1. The remote control 30 is an operating device held by the pilot of the multicopter 1, and includes devices such as a transceiver that transmits electrical signals related to operations from a joystick operated by the pilot to the multicopter 1 and receives electrical signals related to operations from the multicopter 1. The remote control 30 corresponds to an example of an acquisition means of the disclosed technology for acquiring the flight response speed required for the multicopter 1. Here, the flight response speed required for the multicopter 1 includes a takeoff response speed TRS and a landing response speed LRS, which will be described later.

In the multicopter 1 of this embodiment, each motor 24, the battery 31, and the engine 41 form a series hybrid system. That is, in this multicopter 1, the engine 41 is used only for generating electricity with the generator 42, each motor 24 is used to rotate and drive each rotor 25, and the battery 31 is used to charge and discharge the electricity generated by the generator 42. In this way, the multicopter 1 is designed to fly by operating the generator 42 with the power of the engine 41 to generate electricity, and operating each motor 24 with the generated electricity to rotate each rotor 25. In addition, in this multicopter 1, the excess electricity generated by the generator 42 with the power of the engine 41 after being supplied to each motor 24 is temporarily charged and stored in the battery 31, and is supplied from the battery 31 to each motor 24 as needed.

The multicopter 1 configured as described above is adapted to realize various flight modes by supplying power to each motor 24 and rotating each of the multiple rotors 25. That is, the multicopter 1 realizes hovering flight by balancing the lift generated by each rotor 25 with the gravity acting on the multicopter 1 by controlling the rotation speed of each rotor 25. The multicopter 1 realizes ascending flight by making the lift generated by each rotor 25 greater than the gravity acting on the multicopter 1, and realizes descending flight by making the lift generated by each rotor 25 smaller than the gravity acting on the multicopter 1. In addition, the multicopter 1 realizes forward, backward, and left/right movement flight by controlling the rotation speed of each rotor 25 and creating an imbalance in the lift generated by each rotor 25. Furthermore, the multicopter 1 realizes turning (rotational) flight by setting a difference in the rotation speed of each rotor 25 that rotates relative to each other.

The main controller 33 sends an electrical signal to the power control unit 35 regarding a power supply switching command, thereby controlling the supply of power generated by the generator 42 to each motor 24 and the charging of the battery 31, and also controlling the discharging of the power charged in the battery 31 to each motor 24.

[About the power generation engine system]
Next, a description will be given of the generator engine system 15. Fig. 3 is a schematic diagram showing the generator engine system 15 of this embodiment and some of its associated devices. The configuration of the generator engine system 15 will be described in detail below with reference to Fig. 3.

This generator engine system (hereinafter simply referred to as the "engine system") 15 includes an engine 41 consisting of a single cylinder. The engine 41 is a four-stroke reciprocating engine, and includes one cylinder 52 including a combustion chamber, a crankshaft 53, and other well-known components. The engine 41 is provided with an intake passage 54 through which intake air flows to the engine 41 to introduce intake air into the cylinder 52, and an exhaust passage 55 for leading exhaust air from the cylinder 52. An air cleaner 56 is provided at the entrance of the intake passage 54. A surge tank 54a is provided in the middle of the intake passage 54, and a throttle device 57 is provided upstream of the surge tank 54a. The throttle device 57 opens and closes to adjust the amount of intake air flowing through the intake passage 54. The throttle device 57 is composed of a poppet valve, and includes a valve body (not shown) that reciprocates relative to a valve seat, and a step motor 58 for driving the valve body to change the opening degree. The engine system 15 of this embodiment is not provided with a throttle sensor for detecting the opening of the valve body (throttle opening). The throttle device 57 adjusts the amount of intake air flowing through the intake passage 54 by opening and closing the flow path with the valve body. The throttle device 57 corresponds to an example of the output adjustment means of this disclosed technology for adjusting the output of the engine 41. Meanwhile, a catalyst 59 for purifying the exhaust is provided in the exhaust passage 55.

The intake passage 54 is provided with one injector 60 for injecting fuel into the passage 54. The injector 60 is configured to inject fuel (gasoline) supplied from the fuel tank 32 described above. The engine 41 of this embodiment operates with an engine cycle including a series of intake strokes, compression strokes, explosion strokes, and exhaust strokes. In the intake passage 54, a combustible mixture is formed by the intake air introduced during the intake stroke of the engine cycle and the fuel injected into the intake passage 54 from the injector 60.

The engine 41 is provided with one spark plug 61 and one ignition coil 62 corresponding to each cylinder 52. The spark plug 61 sparks upon receiving an ignition signal output from the ignition coil 62. In the cylinder 52, the mixture explodes and burns due to the spark action of the spark plug 61 during the compression stroke of the engine cycle, and the explosion stroke progresses. The exhaust gas after combustion is discharged from the cylinder 52 to the exhaust passage 55 during the exhaust stroke. The exhaust gas flows through the catalyst 59, where it is purified, and is discharged to the outside. By periodically repeating this series of engine cycles with a crank angle of 720°CA, the crankshaft 53 of the engine 41 rotates, and the engine 41 obtains an output. In this embodiment, the crankshaft 53 of the engine 41 is directly connected to the drive shaft of the generator 42. Therefore, the rotation speed of the drive shaft of the generator 42 becomes the same as the rotation speed of the crankshaft 53.

The various sensors 71, 72, 73 provided in correspondence with the engine 41 constitute a means for detecting the operating state of the engine 41. The engine temperature sensor 71 provided in the engine 41 detects the temperature of the cylinder block of the engine 41 as the engine temperature THE, and outputs an electrical signal corresponding to the detected value. The rotation speed sensor 72 provided in the engine 41 detects the rotation speed of the crankshaft 53 as the engine rotation speed NE, and outputs an electrical signal corresponding to the detected value. The intake pressure sensor 73 provided in the surge tank 54a detects the intake pressure PM in the surge tank 54a (intake passage 54), and outputs an electrical signal corresponding to the detected value.

This engine system 15 includes the aforementioned engine control unit 50 for controlling the operation of the engine 41. Various sensors 71 to 73 are connected to the engine control unit 50. In addition, the step motor 58 of the throttle device 57, each injector 60, and an ignition coil 62 are also connected to the engine control unit 50. As is well known, the engine control unit 50 includes a central processing unit (CPU), various memories, external input circuits, external output circuits, etc.

In this embodiment, the engine control unit 50 controls the throttle device 57 (step motor 58), each injector 60, and ignition coil 62 based on electrical signals from various sensors 71 to 73 to operate the engine 41.

Here, FIG. 4 shows a graph of the relationship between the engine speed and the generator 42 current (generated current) during takeoff of the multicopter 1 and the equal fuel consumption rate line EFCL, the equal power line EOL, the engine full-throttle performance line WOT, the equal voltage line IL, and the operating line OL. In FIG. 4, the equal fuel consumption rate line EFCL is shown by a dashed line, the equal power line EOL is shown by a solid line, the engine full-throttle performance line WOT is shown by a thick two-dot dashed line, the equal voltage line IL is shown by a dashed line, and the operating line OL is shown by a thick solid line. The operating line OL is set so as to be perpendicular to the equal fuel consumption rate line EFCL. The multiple equal voltage lines IL have increasing voltage from the left side A1 to the right side A2 of the arrangement. The multiple equal power lines EOL have increasing output from the lower side B1 to the upper side B2 of the arrangement. The multiple constant fuel consumption rate lines EFCL have increasing fuel consumption rates from the center C1 to the outside C2 of the arrangement. In this embodiment, the output of the engine 41 is set to transition on the operating line OL so that the flight output at the time of takeoff of the multicopter 1 and the power generation output of the generator 42 are the same. When the multicopter 1 takes off, the power control unit 35 starts the operation of extracting power from the generator 42 at the operating point P1 on the operating line OL where the fuel consumption of the engine 41 is optimal, and changes the generated power along the operating line OL until the fuel consumption operating point P2 on the operating line OL.

In this embodiment of the multicopter 1, even if power is generated by the generator 42 during takeoff, most of the flight power required for takeoff must be compensated for by discharging the battery 31, which requires the battery 31 to be made larger and heavier. Therefore, in order to minimize the compensation of power by discharging the battery 31 during takeoff of the multicopter 1 and to reduce the size and weight of the battery 31, the main controller 33 executes the following takeoff output control.

Here, the main controller 33 is configured to supply the generated power PG (see Figures 8 to 10) from the generator 42 to each motor 24 in order to satisfy the flight power FP (see Figures 8 to 10) required for the takeoff of the multicopter 1 as a prerequisite for executing the takeoff output control, and to discharge the battery power BP (see Figures 8 to 10) from the battery 31 to each motor 24 in order to make up for the power shortage caused by the generated power PG alone.

[Power control during takeoff]
Next, a description will be given of the takeoff output control executed by the main controller 33. The contents of this takeoff output control are shown in a flowchart in FIG.

When processing transitions to this routine, the main controller 33 (including the engine control unit 50) waits in step 100 for a determination that the multicopter 1 has taken off, and then transitions to step 110. The main controller 33 determines whether or not a takeoff has been determined based on an electrical signal related to an operation command from the remote control 30.

Next, in step 110, the main controller 33 retrieves the takeoff response speed TRS of the multicopter 1, i.e., the response speed required to take off the multicopter 1. The main controller 33 can retrieve this takeoff response speed TRS based on an electrical signal related to an operation command from the remote control 30. The takeoff response speed TRS corresponds to an example of a flight response speed in this disclosed technology.

Next, in step 120, the main controller 33 determines the response time RT of the generator 42 according to the takeoff response speed TRS. The main controller 33 can determine the response time RT according to the takeoff response speed TRS by, for example, referring to a response time map as shown in FIG. 6. In this map, the response time RT increases in a curved manner as the takeoff response speed TRS increases. In FIG. 6, when the takeoff response speed TRS is a predetermined speed S1 (e.g., 5 m/sec), the response time RT is a predetermined time T1 (e.g., 1 sec).

Next, in step 130, the main controller 33 updates the throttle opening command value TOCV for controlling the operation of the engine 41, and in turn the operation of the generator 42, and controls the throttle device 57 (step motor 58) based on the throttle opening command value TOCV. The main controller 33 can update the throttle opening command value TOCV by adding the update value UV to the previously calculated throttle opening command value (previous command value TOCVo) (Equation 1). The update value UV can be obtained by subtracting the transient start value ESV from the final arrival value FRV and dividing the result of the subtraction by the update step number NUS (Equation 2). The update step number NUS can be obtained by dividing the response time RT by the control period (for example, 16 [ms]) (Equation 3).
TOCV=TOCVo+UV (Equation 1)
UV = (FRV - ESV) ÷ NUS ... (Equation 2)
NUS = RT / 16 (Equation 3)

Now, FIG. 7 shows a graph of only the relationship of the operating line OL to the engine speed and the power generation current in FIG. 4. FIG. 7 shows intermediate operating points Q1, Q2, and Q3 between operating point P1 and fuel efficiency operating point P2 on the operating line OL. According to the processing of step 130, as shown in FIG. 7, there is a transition from intermediate operating point Q1 to intermediate operating point Q2. During this transition, the power generation current is kept constant, and the throttle opening command value TOCV is updated, thereby updating (increasing) the engine speed.

Next, in step 140, the main controller 33 updates the power generation current command value PGCV of the generator 42 and controls the power control unit 35 based on the power generation current command value PGCV. The main controller 33 can update the power generation current command value GCCV by adding the update value CUP to the previously calculated power generation current command value PGCV (previous command value PGCVo) (Equation 4). The update value CUP can be calculated by subtracting the transient start value CEV from the final attainment value CFV and dividing the result of the subtraction by the number of update steps NUS (Equation 5). The number of update steps NUS can be calculated by dividing the response time RT by the control period (e.g., 16 ms) (Equation 6).
PGCV=PGCVo+CUP (Equation 4)
CUP = (CFV - CEV) ÷ NUS ... (Equation 5)
NUS = RT / 16 (Equation 6)

According to the processing of step 140, as shown in FIG. 7, the intermediate operating point Q2 transitions to the intermediate operating point Q3. During this transition, the throttle opening command value TOCV is updated and the power generation current is updated. In this case, the intake volume of the engine 41 is kept constant and the load is increased, so the engine speed decreases.

Then, in step 150, the main controller 33 judges whether the throttle opening command value TOCV and the power generation current command value PGCCV have reached the final destination values FRV and CFV, respectively. That is, the main controller 33 judges whether both the throttle opening command value TOCV has reached the final destination value FRV and the power generation current command value PGCCV has reached the final destination value CFV have been reached. If the result of this judgment is positive, the main controller 33 ends the processing once, and if the result of this judgment is negative, the processing returns to step 130.

According to the above-mentioned takeoff output control, the main controller 33 controls the engine 41 to change the response speed (output response speed) of the generator 42 to output the generated power PG in accordance with the takeoff response speed TRS (flight response speed) acquired by the remote control 30 when the multicopter 1 takes off, and also controls the generated current PGC (see Figures 8 to 10) flowing from the generator 42 to each motor 24.

According to the above-mentioned takeoff output control, when the multicopter 1 takes off, the main controller 33 controls the throttle device 57 in accordance with the acquired takeoff response speed TRS (flight response speed) to adjust the output of the engine 41, thereby changing the response speed (output response speed) at which the generator 42 outputs the generated power PG. Specifically, the main controller 33 controls the throttle device 57 so that the response speed at which the generator 42 outputs the generated power PG becomes faster as the acquired takeoff response speed TRS becomes faster, and controls the throttle device 57 so that the response speed at which the generator 42 outputs the generated power PG becomes slower as the acquired takeoff response speed TRS becomes slower.

[Actions and Effects of Multicopters]
According to the configuration of the multicopter 1 of this embodiment described above, the multicopter 1 flies by supplying power to each motor 24 to rotate each rotor 25. Here, the main controller 33 (control means) controls the operation of the engine 41, the supply of power from the generator 42 to each motor 24, charging from the generator 42 to the battery 31, and discharging from the battery 31 to each motor 24. In order to satisfy the flight power FP required for the takeoff of the multicopter 1, the main controller 33 supplies the generated power PG from the generator 42 to each motor 24, and discharges the battery power BP from the battery 31 to each motor 24 to compensate for the power that is insufficient only with the generated power PG. In addition, the main controller 33 controls the engine 41 to change the response speed (output response speed) at which the generator 42 outputs the generated power PG in accordance with the takeoff response speed TRS (flight response speed) acquired by the remote control 30 (acquisition means) when the multicopter 1 takes off, and controls the generated current flowing from the generator 42 to each motor 24. Therefore, in the multicopter 1, in order to satisfy the flight power FP required for takeoff, the response speed at which the generator 42 outputs the power generation power PG is changed according to the acquired takeoff response speed TRS, and the power generation current flowing from the generator 42 to each motor 24 is controlled, so that the battery power BP borne by the battery 31 to make up for the power that is insufficient only with the power generation power PG of the generator 42 is reduced. Therefore, in the multicopter 1 equipped with the generator 42 driven by the engine 41 and the chargeable and dischargeable battery 31, the battery power BP of the power generation power PG of the generator 42 that satisfies the flight power FP required at takeoff and the battery 31 can be reduced, and the battery 31 can be made smaller and lighter. As a result, the weight increase of the multicopter 1 can be suppressed, thereby extending the cruising distance of the multicopter 1, and improving the payload performance of the multicopter 1.

Figure 8 shows the behavior of various parameters related to the takeoff output control in a time chart when the multicopter 1 takes off quickly in this embodiment. Figure 9 also shows the behavior of various parameters related to the takeoff output control in a time chart when the multicopter 1 takes off slowly in this embodiment. Figure 10 shows the behavior of various parameters in a time chart when the generator response is slow at takeoff in a comparative example different from this embodiment. In Figures 8 to 10, (A) shows the change in power, the thick solid line shows the flight power FP required for the flight of the multicopter 1, and the thick dashed line shows the generated power PG of the generator 42. In Figures 8 to 10, (B) shows the change in the throttle opening command value TOCV, and (C) shows the change in the generated current PGC. In FIG. 9, (A) shows the flight power FP1 shown by a solid line and the generated power PG1 shown by a dashed line, (B) shows the throttle opening command value TOCV1 shown by a solid line, and (C) shows the generated current PGC1 shown by a solid line, all of which are shown for comparison in the case of rapid takeoff.

8, when the multicopter 1 of this embodiment takes off rapidly, when the takeoff starts at time t1, the flight power FP increases rapidly as shown in (A), reaches a peak at time t2, and then decreases rapidly to a constant value. At this time, the power generation PG increases rapidly between time t1 and time t2 in accordance with the change in the flight power FP and becomes a constant value. Also, as shown in (B) and (C), the throttle opening command value TOCV and the power generation current PGC also increase rapidly between time t1 and time t2 in response to the change in the power generation PG and become a constant value. In other words, when the multicopter 1 takes off rapidly, the throttle device 57 responds by opening the valve immediately, the transient response of the generator 42 is accelerated, and the power generation PG increases rapidly with good response. Here, in (A), the part indicated by dots between the flight power FP and the power generation PG indicates the battery power BP that is supplemented by the discharge of the battery 31. The battery power BP that supplements this generated power PG is at its maximum when the flight power FP reaches its peak at time t2. If the battery power BP at this time is the maximum power of the battery 31, the weight of the battery 31 can be determined according to this maximum power.

9, when the multicopter 1 of this embodiment takes off slowly, when the takeoff starts at time t1, the flight power FP increases slowly as shown in (A), reaches a peak at time t3, and then decreases slowly to a constant value. At this time, the power generation PG increases slowly between time t1 and time t3 in accordance with the change in the flight power FP to a constant value. Also, as shown in (B) and (C), the throttle opening command value TOCV and the power generation current PGC also increase slowly between time t1 and time t3 in response to the change in the power generation PG to a constant value. That is, when the multicopter 1 takes off slowly, the throttle device 57 immediately responds by opening the valve slowly, the transient response of the generator 42 is accelerated, and the power generation PG increases slowly. Here, as shown in (A), the peak of the flight power FP at time t3 is smaller than when taking off rapidly, so the maximum value of the battery power BP that supplements the power generation PG at that time is also smaller.

On the other hand, as shown in FIG. 10, when the multicopter in the comparative example takes off rapidly, when the takeoff starts at time t1, the flight power FP increases rapidly as shown in (A), reaches a peak at time t2, and then decreases rapidly to a constant value. At this time, since the transient response of the generator is slow, the generated power PG increases rapidly between time t2 and time t4 with a delay to the change in the flight power FP and then becomes a constant value. Also, as shown in (B) and (C), the throttle opening command value TOCV and the generated current PGC also increase rapidly between time t2 and time t4 in response to the change in the generated power PG and become a constant value. That is, in this comparative example, even if the multicopter takes off rapidly, the opening response of the throttle device is delayed, the transient response of the generator is delayed, and the increase in the generated power PG is delayed. Therefore, in (A), when the flight power FP reaches its peak at time t2, the generated power PG becomes almost zero, so the battery power BP that supplements the generated power PG becomes almost the entire flight power FP. Therefore, if the battery power BP at this time is the maximum power of the battery, the weight of the battery will be determined according to this maximum power. As a result, the weight of the battery will be almost twice as much as in the case shown in FIG. 8, and a large battery will be required. In this embodiment, the capacity of the battery 31 can be reduced to almost half that of the comparative battery.

In addition, according to the configuration of the multicopter 1 of this embodiment, the engine 41 of the power generating engine system 15 drives the generator 42 to generate electricity, and the generated electricity is supplied to each motor 24 to fly the multicopter 1. The generated electricity is also charged to the battery 31 to replenish the charge. Therefore, even if the engine 41 stops and the generator 42 cannot be driven, the electricity charged in the battery 31 can be supplied to each motor 24, making it possible for the multicopter 1 to fly. Therefore, the range and flight time of the multicopter 1 can be extended by the amount that the electricity generated by the generator 42 can be charged to the battery 31.

<Second embodiment>

Next, the second embodiment will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment will be given the same reference numerals and will not be described again. The following description will focus on the differences.

This embodiment differs from the takeoff output control of the first embodiment in terms of the landing output control. In this embodiment, this landing output control is executed in addition to the takeoff output control of the first embodiment.

Here, FIG. 11 shows the relationship between the engine speed and the power generation current of the generator 42 when the multicopter 1 lands, and the constant fuel consumption rate line EFCL, constant power output line EOL, engine full throttle performance line WOT, constant voltage line IL, and operating line OL, in a graph similar to FIG. 4. In this embodiment, the output of the engine 41 is set to transition on the operating line OL so that the flight output and the power generation output of the generator 42 when the multicopter 1 lands are the same. In FIG. 11, when the multicopter 1 lands, the power is changed along the operating line OL from operating point P3 on the operating line OL where the fuel consumption of the engine 41 is optimal, to operating point P1 on the operating line OL.

In this embodiment of the multicopter 1, even when landing, the generated power of the generator 42 is supplied to each motor 24, but because the flight power required for landing is less than the generated power, the surplus generated power must be charged to the battery 31. This also necessitates an increase in the size and weight of the battery 31. Therefore, when the multicopter 1 lands, in order to minimize the charging of the generated power to the battery 31 and to reduce the size and weight of the battery 31, the main controller 33 executes the following output control during landing.

Here, the main controller 33 is configured to supply generated power PG (see Figures 14 to 16) from the generator 42 to each motor 24 in order to satisfy the flight power FP (see Figures 14 to 16) required for landing of the multicopter 1, as a prerequisite for executing output control during landing, and to charge the surplus of generated power PG to the battery 31.

[Power control during landing]
Next, a description will be given of the landing power control executed by the main controller 33. The landing power control is shown in a flowchart in Fig. 12. This flowchart differs from the flowchart in Fig. 5 in that steps 200 to 220 are provided instead of steps 100 to 120.

When processing transitions to this routine, the main controller 33 (including the engine control unit 50) waits in step 200 for a determination that the multicopter 1 has landed, and then transitions to step 210. The main controller 33 determines whether or not a landing determination has been made based on an electrical signal related to an operation command from the remote control 30.

Next, in step 210, the main controller 33 retrieves the landing response speed LRS of the multicopter 1, i.e., the response speed required to land the multicopter 1. The main controller 33 retrieves this landing response speed LRS based on an electrical signal related to an operation command from the remote control 30. The landing response speed LRS corresponds to an example of a flight response speed in this disclosed technology.

Next, in step 220, the main controller 33 determines the response time RT of the generator 42 according to the landing response speed LRS. The main controller 33 can determine the response time RT according to the landing response speed LRS, for example, by referring to a response time map similar to that shown in FIG. 6.

Then, the main controller 33 executes the processes of steps 130 to 150, similar to the takeoff output control.

Now, FIG. 13 shows a graph of only the relationship of the operating line OL to the engine speed and the generated current in FIG. 11. FIG. 13 shows intermediate operating points Q4, Q5, and Q6 between operating point P3 and operating point P1 on the operating line OL during landing. According to the processing of step 130 during landing, as shown in FIG. 13, there is a transition from intermediate operating point Q4 to intermediate operating point Q5. During this transition, the generated current is kept constant, and the throttle opening command value TOCV is updated, thereby updating (reducing) the engine speed.

Furthermore, according to the processing of step 140 during landing, as shown in FIG. 13, there is a transition from intermediate operating point Q5 to intermediate operating point Q6. During this transition, the throttle opening command value TOCV is updated and the power generation current is updated. In this case, the load is reduced while the intake volume of the engine 41 is kept constant, so the engine speed increases.

According to the landing output control described above, the main controller 33 controls the engine 41 to change the response speed (output response speed) at which the generator 42 outputs the generated power PG in accordance with the landing response speed LRS (flight response speed) acquired by the remote control 30 when the multicopter 1 lands, and also controls the generated current PGC (see Figures 14 to 16) flowing from the generator 42 to each motor 24.

[Actions and Effects of Multicopters]
According to the configuration of the multicopter 1 of this embodiment described above, in addition to the actions and effects of the first embodiment, the following actions and effects can be obtained. That is, in order to satisfy the flight power FP required for landing of the multicopter 1, the main controller 33 supplies the generated power PG from the generator 42 to each motor 24 and charges the remaining generated power PG to the battery 31. In addition, the main controller 33 controls the engine 41 to change the response speed (output response speed) at which the generator 42 outputs the generated power PG in accordance with the landing response speed LRS (flight response speed) acquired by the remote control 30 when the multicopter 1 lands, and controls the generated current PGC flowing from the generator 42 to each motor 24. Therefore, in the multicopter 1, in order to satisfy the flight power FP required for landing, the response speed at which the generator 42 outputs the generated power PG is changed according to the acquired landing response speed LRS, and the generated current PGC flowing from the generator 42 to each motor 24 is controlled, so that the surplus power of the generated power PG of the generator 42 that is not supplied to each motor 24 is reduced, and the surplus power to be charged to the battery 31 is reduced. Therefore, the surplus of the generated power PG that is charged to the battery 31 out of the generated power PG of the generator 42 that satisfies the flight power FP required when the multicopter 1 lands can be reduced, and the battery 31 can be made smaller and lighter. In this respect, the weight increase of the multicopter 1 can be suppressed, thereby extending the cruising distance of the multicopter 1 and improving the payload performance of the multicopter 1.

Figure 14 shows the behavior of various parameters related to the landing output control in a time chart when the multicopter 1 lands quickly in this embodiment. Figure 15 shows the behavior of various parameters related to the landing output control in a time chart when the multicopter 1 lands slowly in this embodiment. Figure 16 shows the behavior of various parameters in a time chart when the generator response is slow during landing in a comparative example different from this embodiment. In Figures 14 to 16, (A) to (C) are similar to Figures 8 to 10. In Figure 15, the flight power FP1 shown by a solid line in (A) and the generated power PG1 shown by a dashed line, the throttle opening command value TOCV1 shown by a solid line in (B), and the generated current PGC1 shown by a solid line in (C) are shown for comparison in the case of a rapid landing.

As shown in FIG. 14, when the multicopter 1 of this embodiment lands rapidly, when the landing starts at time t1, the flight power FP decreases rapidly as shown in (A) and becomes almost zero at time t2. At this time, the generated power PG decreases rapidly between time t1 and time t2 in accordance with the change in the flight power FP and becomes almost zero. Also, as shown in (B) and (C), the throttle opening command value TOCV and the generated current PGC also decrease between time t1 and time t2 in response to the change in the generated power PG and become constant values. That is, when the multicopter 1 lands rapidly, the throttle device 57 immediately responds by closing the valve, the transient response of the generator 42 is accelerated, and the generated power PG decreases rapidly with good responsiveness. Here, in (A), the generated power PG is greater than the flight power FP, and the portion indicated by the dots between the generated power PG and the flight power FP is the surplus generated power PG not used for flight, and indicates the charging power CP to be charged to the battery 31. Therefore, the charging power CP becomes maximum at some time between time t1 and time t2 when the multicopter 1 starts and finishes landing. If this maximum charging power CP is set as the maximum power of the battery 31, the weight of the battery 31 can be determined according to this maximum power.

As shown in FIG. 15, when the multicopter 1 slowly lands, when the landing starts at time t1, the flight power FP slowly decreases as shown in (A) and becomes almost zero at time t3. At this time, the generated power PG slowly decreases between time t1 and time t3 in accordance with the change in the flight power FP and becomes almost zero. Also, as shown in (B) and (C), the throttle opening command value TOCV and the generated current PGC slowly decrease between time t1 and time t2 earlier than the change in the generated power PG and become constant values. In other words, when the multicopter 1 slowly lands, the throttle device 57 immediately and slowly responds to close the valve, the transient response of the generator 42 is accelerated, and the generated power PG gradually decreases. Here, as shown in (A), the maximum value of the charging power CP at a certain time between time t1 and time t3 is smaller than in the case of a rapid landing.

On the other hand, as shown in FIG. 16, when the multicopter in the comparative example lands rapidly, when the landing starts at time t1, the flight power FP decreases rapidly as shown in (A) and becomes almost zero at time t2. At this time, since the transient response of the generator is delayed, the generated power PG decreases between time t1 and time t4 with a delay from the change in the flight power FP and becomes almost zero. Also, as shown in (B) and (C), the throttle opening command value TOCV and the generated current PGC decrease and become constant between time t1 and time t2, which is earlier than the change in the generated power PG. That is, in this comparative example, even if the multicopter lands rapidly, the closing response of the throttle device is delayed, the transient response of the generator is delayed, and the decrease in the generated power PG is delayed. Therefore, in (A), even after the landing starts at time t1 and ends at time t2, the generator continues to generate power until time t4, and the charging power CP charged in the battery increases. Therefore, if the entire charging power CP at this time were to be charged to the battery, the battery capacity would be large and the weight would be several times (about four times) that of the case shown in FIG. 14, requiring a large battery. In this embodiment, the capacity of the battery 31 can be reduced to a fraction (about one-quarter) of the capacity of the comparative battery.

[About another embodiment]
It should be noted that the disclosed technology is not limited to the above-described embodiments, and parts of the configuration can be appropriately modified and implemented without departing from the spirit of the disclosed technology.

In each of the above embodiments, the appearance of the multicopter 1 shown in FIG. 1 is an example, and the shape of the aircraft 11, the number and arrangement of the motors 24 and rotors 25, etc. can be changed as appropriate.

This disclosed technology can be applied to a multicopter equipped with an engine-driven generator and a rechargeable battery.

1 Multicopter 24 Motor 25 Rotor 30 Remote control (acquisition means)
31 Battery 33 Main controller (control means)
41 Engine 42 Generator
57 Throttle device (output adjustment means)
TRS Takeoff response speed (flight response speed)
LRS Landing Response Speed (Flight Response Speed)
PGC: Generated current FP: Flight power PG: Generated power BP: Battery power CP: Charging power

Claims (4)

A plurality of rotors;
a motor for driving and rotating each of the rotors;
a battery configured to be capable of charging and discharging power supplied to the motor;
a generator for generating power supplied to the motor and power charged to the battery;
an engine for driving the generator;
A multicopter includes a control unit for controlling operation of the engine, supply of electric power from the generator to the motor, charging of the battery from the generator, and discharging of the battery to the motor, and the multicopter flies by supplying electric power to the motor to rotate each rotor,
Further comprising an acquisition means for acquiring a flight response speed required for the multicopter,
The control means is configured to supply generated power from the generator to the motor in order to satisfy the flight power required for takeoff of the multicopter, and to discharge battery power from the battery to the motor in order to compensate for power that is insufficient with only the generated power,
The control means controls the engine to change the output response speed of the generator to match the flight response speed acquired by the acquisition means when the multicopter takes off, and controls the generating current flowing from the generator to the motor. The multicopter according to claim 1,
The control means is configured to supply generated power from the generator to the motor in order to satisfy flight power required for landing of the multicopter, and to charge the battery with the surplus of the generated power,
The control means controls the engine to change the output response speed of the generator to match the flight response speed acquired by the acquisition means when the multicopter lands, and controls the generating current flowing from the generator to the motor. The multicopter according to claim 1 or 2,
The engine further includes an output adjusting means for adjusting the output of the engine,
The control means controls the output adjustment means to adjust the output of the engine in accordance with the acquired flight response speed, thereby changing the output response speed of the generator. The multicopter according to claim 3,
The control means controls the output adjustment means so that the output response speed of the generator becomes faster as the acquired flight response speed becomes faster, and controls the output adjustment means so that the output response speed of the generator becomes slower as the acquired flight response speed becomes slower.

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