Flying object

Abstract

The flying object (1) having a main body portion (2) and a plurality of propellers (11-18) radially arranged symmetrically about the main body portion (2) on the left and right includes: a plurality of motors (21-28) that rotate the plurality of propellers (11-18) respectively; a plurality of storage batteries (51-58) that supply current to the plurality of motors (21-28) respectively; and a reserve storage battery (59) that is connected to the plurality of storage batteries (51-58) through power wirings (H11-H18) respectively. The same number of motors (21-28) are provided on the left and right respectively, and the same number of storage batteries (51-58) are provided on the left and right respectively. The reserve storage battery (59) is provided on the center line of the left and right of the main body portion (2).

Description

Technical Field

[0001] The present invention relates to a flying object equipped with multiple motors. Background Art

[0002] In a flying object having multiple motors, such as a drone, when multiple battery packs are mounted (for example, refer to Patent Document 1) and a method of establishing a one-to-one correspondence and connection between the multiple motors and the multiple battery packs is adopted, due to the deviation of the loads among the multiple motors, a deviation occurs in the remaining capacity (SOC: State Of Charge) among the multiple battery packs. In this case, at the moment when the SOC of one battery pack is 0%, even if the SOC of other battery packs is not 0%, flight cannot continue. That is, the energy of other battery packs cannot be effectively utilized. This means that the actual flight distance is shorter than the flyable distance that could originally be achieved with the total energy of the multiple battery packs.

[0003] In addition, due to the deviation of the loads among the multiple motors, a deviation also occurs in the charge and discharge rates and the depth of discharge among the multiple battery packs, and a deviation also occurs in the degree of progress of the deterioration state (SOH: State Of Health). The full charge capacity (FCC) of the battery pack with a reduced SOH is less than that of other battery packs, so the reduction in the flyable distance is further accelerated.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-222031 Summary of the Invention

[0007] -Problems to be Solved by the Invention-

[0008] In view of this situation, the present disclosure is made, and an object thereof is to provide a technique for suppressing the influence on the body balance and effectively utilizing the capacity of multiple power storage groups mounted on a flying object.

[0009] -Means for Solving the Problems-

[0010] To solve the above problems, a flying object according to a certain aspect of the present disclosure is a flying object including a main body portion and a plurality of propellers symmetrically arranged radially from the main body portion on the left and right. The flying object includes: a plurality of motors that rotate the plurality of propellers respectively; a plurality of power storage groups that supply current to the plurality of motors respectively; and a reserve power storage group that is connected to the plurality of power storage groups respectively through power wirings. The same number of the plurality of motors is provided on each of the left and right sides, the same number of the plurality of power storage groups is provided on each of the left and right sides, and the reserve power storage group is provided on the center line of the left and right sides of the main body portion.

[0011] -Advantages of the Invention-

[0012] According to the present disclosure, it is possible to suppress the influence on the body balance and effectively utilize the capacities of a plurality of power storage units mounted on the flying object. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic view of the flying object according to the embodiment as viewed from above.

[0014] Figure 2 It is a schematic view of the flying object according to the embodiment as viewed from the front.

[0015] Figure 3 It is a schematic view of the flying object according to the modified example of the embodiment as viewed from above.

[0016] Figure 4 It is a functional block diagram of the flying object equipped with the power supply system according to the embodiment.

[0017] Figure 5 It is a diagram showing an example of the internal structure of the power storage unit mounted on the flying object.

[0018] Figure 6 It is a diagram showing the connection state during charging of eight power storage units mounted on the flying object.

[0019] Figure 7 It is a diagram showing an example of the state of the power supply system during the flight of the flying object.

[0020] Figure 8 It is a diagram (Part 1) for explaining an example of the equalization process of the capacities between the first power storage unit and the eighth power storage unit while the flying object is stopped.

[0021] Figure 9 It is a diagram (Part 2) for explaining an example of the equalization process of the capacities between the first power storage unit and the eighth power storage unit while the flying object is stopped.

[0022] Figure 10 It is a diagram (Part 3) for explaining an example of the equalization process of the capacities between the first power storage unit and the eighth power storage unit while the flying object is stopped. DETAILED DESCRIPTION OF THE INVENTION

[0023] Figure 1 It is a schematic view of the flying object 1 according to the embodiment as viewed from above. Figure 2This is a schematic view of the flying object 1 according to the embodiment as observed from the front. The flying object 1 according to the embodiment is a multi-rotor helicopter known as a flying car or a manned drone. The flying object 1 according to the embodiment includes eight propellers 11-18. Four arms are provided diagonally on the main body 2, and two propellers are provided respectively above and below in the vertical direction at the front end of each arm. Thus, the flying object 1 has a structure in which the eight propellers 11-18 are radially arranged symmetrically left and right from the main body 2.

[0024] In the first support shaft X1 that supports the first propeller 11 and the second propeller 12, a first motor 21 for rotating the first propeller 11 and a second motor 22 for rotating the second propeller 12 are respectively provided. Similarly, in the second support shaft X2 that supports the third propeller 13 and the fourth propeller 14, a third motor 23 and a fourth motor 24 are provided, in the third support shaft X3 that supports the fifth propeller 15 and the sixth propeller 16, a fifth motor 25 and a sixth motor 26 are provided, and in the fourth support shaft X4 that supports the seventh propeller 17 and the eighth propeller 18, a seventh motor 27 and an eighth motor 28 are provided.

[0025] Near the root of the first arm A1 on the main body 2 side that connects the main body 2 and the first support shaft X1, a first battery pack 51 for supplying current to the first motor 21 and a second battery pack 52 for supplying current to the second motor 22 are provided. Similarly, a third battery pack 53 and a fourth battery pack 54 are provided near the root of the second arm A2 on the main body 2 side, a fifth battery pack 55 and a sixth battery pack 56 are provided near the root of the third arm A3 on the main body 2 side, and a seventh battery pack 57 and an eighth battery pack 58 are provided near the root of the fourth arm A4 on the main body 2 side.

[0026] In the first arm A1, a first wire harness H1 that connects between the first motor 21 and the first battery pack 51 and a second wire harness H2 that connects between the second motor 22 and the second battery pack 52 are passed through. Similarly, in the second arm A2, a third wire harness H3 and a fourth wire harness H4 are passed through, in the third arm A3, a fifth wire harness H5 and a sixth wire harness H6 are passed through, and in the fourth arm A4, a seventh wire harness H7 and an eighth wire harness H8 are passed through.

[0027] In order to suppress the deviation of the voltage drop caused by the resistance of the first wire harnesses H1-H8, it is desirable to make the wiring resistances of the first wire harnesses H1-H8 consistent. Specifically, it is desirable to connect between the first propeller 11 - the eighth propeller 18 and the first battery pack 51 - the eighth battery pack 58 respectively through the first wire harnesses H1-H8 having the same length and thickness.

[0028] In the present embodiment, in addition to the first battery storage groups 51 to 8th battery storage groups 58, a reserve battery storage group 59 is additionally provided. The function of the reserve battery storage group 59 will be described later. The first battery storage groups 51 to 8th battery storage groups 58 and the reserve battery storage group 59 are respectively connected through the 11th wiring harness H11 to 18th wiring harnesses H18.

[0029] Figure 1 The flying object 1 shown is designed such that the center of gravity position of the flying object 1 can be located at the center position in the front, rear, left, and right of the flying object 1. In unmanned multi-rotor helicopters used for aerial photography, pesticide spraying, etc., it is often designed to be symmetric left and right and symmetric front and rear. In this case, the center of gravity position of the airframe coincides with the center position. In the case of a manned multi-rotor helicopter in which people ride, since seats are required, it is difficult to design the airframe to be symmetric front and rear.

[0030] In Figure 1 In the example shown, it is designed to adjust the positions of the seats and other loaded objects so that the center of gravity position is at the intersection point (the center point of the flying object 1) of the left-right center line L1 and the front-rear center line L2 of the flying object 1 (main body part 2). The reserve battery storage group 59 is provided at this center of gravity part. The setting position of the reserve battery storage group 59 in the up-down direction (vertical direction) is not particularly limited, but it is preferably set at a position lower than the passengers. For example, it is preferably set below the seat or below the main body part 2.

[0031] In order to suppress the deviation of the voltage drop caused by the resistance of the 11th wiring harness H11 to 18th wiring harnesses H18, it is desirable to make the wiring resistances of the 11th wiring harness H11 to 18th wiring harnesses H18 the same.

[0032] As Figure 1 shown, when the reserve battery storage group 59 is provided at the central part of the airframe (main body part 2), the distances from the reserve battery storage group 59 to the first battery storage groups 51 to 8th battery storage groups 58 are equal, and naturally the wiring lengths are equal. That is to say, if the reserve battery storage group 59 and the first battery storage groups 51 to 8th battery storage groups 58 are respectively connected through the same wiring harnesses, the wiring resistances can be made the same.

[0033] Figure 3 is a schematic view of the flying object 1 according to a modified example of the embodiment as viewed from above. The flying object 1 according to the modified example is designed such that the front and rear center of gravity positions are located at positions shifted more forward than the front-rear center line L2. In the case of a manned multi-rotor helicopter, since the orientation of the front as the traveling direction is determined, it is often designed such that the center of gravity position is located at a position more forward than the center position of the lifting force. In this case, the moment for the nose to drop acts, and it is easy to accelerate in the traveling direction. In addition, the stability of the nose rising and falling is improved.

[0034] In Figure 3In the example shown, the center of gravity is designed to be at the intersection of the left - right center line L1 of the flying object 1 and the line L3 that slides forward from the front - rear center line L2. The reserve battery pack 59 is provided at this center - of - gravity portion.

[0035] In Figure 3 the example shown, the distances from the reserve battery pack 59 to the first battery pack 51 - the eighth battery pack 58 are not equal. Even in such a state, it is desirable to connect the reserve battery pack 59 and the first battery pack 51 - the eighth battery pack 58 respectively through the eleventh wire harness H11 - the eighteenth wire harness H18 so that the respective wiring resistances between the reserve battery pack 59 and the first battery pack 51 - the eighth battery pack 58 are equal. When using the same wire harness, the eleventh wire harness H11 - the fourteenth wire harness H14 connected to the first battery pack 51 - the fourth battery pack 54 close to the reserve battery pack 59 are arranged with play.

[0036] In addition, different types of wire harnesses can also be used in the eleventh wire harness H11 - the fourteenth wire harness H14 connected to the first battery pack 51 - the fourth battery pack 54 close to the reserve battery pack 59 and the fifteenth wire harness H15 - the eighteenth wire harness H18 connected to the fifth battery pack 55 - the eighth battery pack 58 far from the reserve battery pack 59. For example, by using wire harnesses with different thicknesses, the respective wiring resistances between the reserve battery pack 59 and the first battery pack 51 - the eighth battery pack 58 can be made substantially equal.

[0037] Figure 4 is a functional block diagram of the flying object 1 equipped with the power supply system according to the embodiment. The flying object 1 includes: eight propellers 11 - 18, eight motors 21 - 28, eight motor drive units 31 - 38, a body control unit 40, a sensor 41, and a power supply system.

[0038] The eight motors 21 - 28 are respectively connected to the rotation shafts of the eight propellers 11 - 18. The eight motor drive units 31 - 38 respectively drive the eight motors 21 - 28. The eight motor drive units 31 - 38 respectively include inverters. Each inverter converts the direct - current supplied from each battery pack into an alternating - current corresponding to the command value specified from the body control unit 40 and supplies it to each motor. The eight motors 21 - 28 rotate the eight propellers 11 - 18 at speeds corresponding to the alternating - currents respectively supplied from the eight motor drive units 31 - 38.

[0039] The airframe control unit 40 can include a microcomputer and a non-volatile memory (e.g., EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory). The sensor 41 is a general term for various sensors mounted on the flying object 1. For example, as the sensor 41, a gyro sensor, an acceleration sensor, a barometric pressure sensor, an ultrasonic sensor, a magnetic azimuth sensor, and a GPS (Global Positioning System) sensor are mounted.

[0040] The gyro sensor detects the angular velocity of the flying object 1 and outputs it to the airframe control unit 40. The acceleration sensor detects the acceleration of the flying object 1 and outputs it to the airframe control unit 40. The airframe control unit 40 infers the attitude and speed of the flying object 1 based on the input angular velocity and acceleration. The barometric pressure sensor detects the barometric pressure at the location of the flying object 1 and outputs it to the airframe control unit 40. The ultrasonic sensor receives the reflected wave of the radiated ultrasonic wave and outputs it to the airframe control unit 40. The airframe control unit 40 infers the altitude of the flying object 1 based on the input barometric pressure and the reflected wave of the ultrasonic wave.

[0041] The magnetic azimuth sensor detects the azimuth based on the geomagnetism and outputs it to the airframe control unit 40. The airframe control unit 40 infers the traveling direction of the flying object 1 based on the input azimuth. The GPS sensor receives radio waves containing respective transmission times from multiple GPS satellites, detects the latitude and longitude of the receiving location based on the multiple transmission times respectively contained in the received multiple radio waves, and outputs it to the airframe control unit 40. The airframe control unit 40 infers the current position of the flying object 1 based on the input latitude and longitude.

[0042] The airframe control unit 40 determines the respective rotational speeds of the eight motors 21-28 based on a prescribed airframe control program, the detection information input from the sensor 41, and the operation information of the driver riding on the main body unit 2. In addition, in the case of a drone, instead of the operation information of the driver riding on the main body unit 2, at least one of remotely transmitted operation information and a prescribed automatic flight program is used.

[0043] The airframe control unit 40 generates command values respectively set for the eight motor drive units 31-38 based on the determined respective rotational speeds of the eight motors 21-28. The airframe control unit 40 is respectively connected to the eight motor drive units 31-38 through signal lines (not shown). The airframe control unit 40 provides the generated command values to the eight motor drive units 31-38 respectively via the respective signal lines. In addition, signal lines may not be provided, and the command values may be wirelessly transmitted from the airframe control unit 40 to the eight motor drive units 31-38 respectively.

[0044] When the airframe control unit 40 moves the flying object 1 in any direction, it reduces the rotational speed of the motor in the traveling direction and increases the rotational speed of the motor in the direction opposite to the traveling direction. Through this control, the flying object 1 assumes a forward-tilted posture, and the flying object 1 can move in the traveling direction.

[0045] In addition, the rotational directions of adjacent motors of the flying object 1 are opposite to each other. When the airframe control unit 40 rotates the flying object 1 in any direction, it increases the rotational speed of the motor rotating in the direction opposite to the direction in which it rotates, relative to the rotational speed of the motor rotating in the same direction as the direction in which it rotates. Through this control, a rotational force in the direction of rotating the flying object 1 is generated, and the flying object 1 rotates in the rotational direction.

[0046] The power supply system mounted on the flying object 1 includes: eight battery packs 51 - 58, a standby battery pack 59, eight first switches S11 - S18, eight second switches S21 - S28, a DC / DC converter 60, and a power supply control unit 70.

[0047] The eight battery packs 51 - 58 are power supply devices for respectively supplying current to the eight motor drive units 31 - 38. The standby battery pack 59 is an auxiliary power supply device that can supply current to, or absorb current from, the eight first current paths connecting the eight motor drive units 31 - 38 and the eight battery packs 51 - 58.

[0048] The eight first switches S11 - S18 are respectively inserted into eight second current paths connecting the eight first current paths and the standby battery pack 59. The standby battery pack 59 can be conducted to any current path of the eight first current paths via the eight first switches S11 - S18. The eight second switches S21 - S28 are respectively inserted between the eight connection points N1 - N8 connected to the eight second current paths and the eight battery packs 51 - 58 on the eight first current paths. The first switches S11 - S18 and the second switches S21 - S28 can be composed of relays or semiconductor switches.

[0049] The front ends of the eight second current paths on the standby battery pack 59 side are coupled into one. A DC / DC converter 60 is connected between the coupling point N9 and the standby battery pack 59. The DC / DC converter 60 is a bidirectional DC / DC converter that can control the charging voltage or charging current when charging the standby battery pack 59, and the discharging voltage or discharging current when discharging from the standby battery pack 59. At the coupling point N9, the charging path connected to the charging port P1 is also connected.

[0050] The power control unit 70 can include a microcomputer and a non-volatile memory. The power control unit 70 is connected to eight battery packs 51 - 58 via a communication line 71. The power control unit 70 can control eight first switches S11 - S18 and eight second switches S21 - S28 to adjust the capacity balance among the eight battery packs 51 - 58.

[0051] Figure 5 It is a diagram showing an example of the internal structure of the battery pack 51 mounted on the flying object 1. The battery pack 51 includes a battery module 511 and a control board 512. The battery module 511 includes a plurality of cells E1 - En connected in series. Additionally, the battery module 511 can be formed by connecting multiple battery modules in series / series-parallel. Lithium-ion battery cells, nickel-metal hydride battery cells, lead battery cells, electric double layer capacitor cells, lithium-ion capacitor cells, etc. can be used for the cells. Hereinafter, in this specification, an example of using lithium-ion battery cells (nominal voltage: 3.6 - 3.7V) is assumed. The number of cells E1 - En connected in series is determined according to the driving voltage of the motor 21.

[0052] A shunt resistor Rs is connected in series with the plurality of cells E1 - En. The shunt resistor Rs functions as a current detection element. Additionally, a Hall element can be used instead of the shunt resistor Rs. In the battery module 511, a temperature sensor T1 (e.g., a thermistor) for detecting the temperature of the plurality of cells E1 - En is provided. Additionally, multiple temperature sensors T1 can be provided.

[0053] On the control board 512, a voltage measurement unit 513, a temperature measurement unit 514, a current measurement unit 515, and a management unit 516 are provided. The voltage measurement unit 513 is connected to each node of the plurality of cells E1 - En connected in series via a plurality of voltage measurement lines. The voltage measurement unit 513 measures the voltage of each cell E1 - En by measuring the voltage between adjacent two voltage measurement lines respectively. The voltage measurement unit 513 sends the measured voltage of each cell E1 - En to the management unit 516.

[0054] Since the voltage measurement unit 513 is at a high voltage relative to the management unit 516, the voltage measurement unit 513 and the management unit 516 are connected via a communication line in an insulated state. The voltage measurement unit 513 can include an ASIC (Application Specific Integrated Circuit) or a general-purpose analog front-end IC. The voltage measurement unit 513 includes a multiplexer and an A / D converter. The multiplexer sequentially outputs the voltage between adjacent two voltage measurement lines to the A / D converter from the top. The A / D converter converts the analog voltage input from the multiplexer into a digital value.

[0055] The temperature measurement unit 514 includes a voltage-dividing resistor and an A / D converter. The A / D converter converts the analog voltage divided by the temperature sensor T1 and the voltage-dividing resistor into a digital value and outputs it to the management unit 516. The management unit 516 infers the temperatures of the plurality of cells E1-En based on this digital value.

[0056] The current measurement unit 515 includes a differential amplifier and an A / D converter. The differential amplifier amplifies the voltage across both ends of the shunt resistor Rs and outputs it to the A / D converter. The A / D converter converts the analog voltage input from the differential amplifier into a digital value and outputs it to the management unit 516. The management unit 516 infers the current flowing through the plurality of cells E1-En based on this digital value.

[0057] In addition, when an A / D converter is installed in the management unit 516 and an analog input port is provided in the management unit 516, the temperature measurement unit 514 and the current measurement unit 515 can also output an analog voltage to the management unit 516 and convert it into a digital value through the A / D converter in the management unit 516.

[0058] The management unit 516 can include a microcomputer and a non-volatile memory. The management unit 516 manages the states of the plurality of cells E1-En based on the voltages, temperatures, and currents of the plurality of cells E1-En measured by the voltage measurement unit 513, the temperature measurement unit 514, and the current measurement unit 515.

[0059] The management unit 516 can infer the respective SOCs and SOHs of the plurality of cells E1-En. The management unit 516 can infer the SOC by the OCV (Open Circuit Voltage) method or the current integration method.

[0060] The SOH is defined by the ratio of the current FCC to the initial FCC, and the lower the value (the closer to 0%) indicates the more advanced the deterioration. The SOH can be obtained by measuring the capacity based on full charge and discharge, or by summing up the storage deterioration and the cycle deterioration. The storage deterioration can be inferred based on the SOC, temperature, and storage deterioration rate. The cycle deterioration can be inferred based on the SOC range used, temperature, current rate, and cycle deterioration rate. The storage deterioration rate and the cycle deterioration rate can be derived in advance through experiments and simulations. The SOC, temperature, SOC range, and current rate can be obtained through measurements.

[0061] In addition, the SOH can also be inferred based on the correlation with the internal resistance of the cell. The internal resistance can be inferred by dividing the voltage drop generated when a specified current flows through the cell for a specified time by the current value. The internal resistance has a relationship of decreasing as the temperature rises and increasing as the SOH decreases.

[0062] The battery pack 51 has, as external terminals: a positive terminal + connected to the positive electrode of the battery module 511, a negative terminal - connected to the negative electrode of the battery module 511, and a control terminal CNT connected to the control substrate 512. A communication line 71 is connected to the control terminal CNT. The management unit 516 transmits, via the communication line 71, the monitoring data of the plurality of cells E1 - En to the power control unit 70 at each specified period. As the monitoring data, the voltages, temperatures, and currents of the plurality of cells E1 - En are transmitted. Further, regarding the SOC and SOH, the management unit 516 may infer the SOC and SOH and transmit them to the power control unit 70, or may perform the inference based on the voltages, temperatures, and currents received by the power control unit 70.

[0063] The communication protocol between the eight battery packs 51 - 58 and the power control unit 70 can use, for example, RS - 485, TCP / IP, CAN (Controller Area Network), etc. Further, the eight battery packs 51 - 58 and the power control unit 70 can be connected by wireless communication or can be connected by power line communication.

[0064] Figure 6 It is a diagram showing the connection state during charging of the eight battery packs 51 - 58 mounted on the flying object 1. By inserting the charging cable 4a into the charging port P1, the eight battery packs 51 - 58 and the reserve battery pack 59 can be charged from the charger 4 provided outside. In the present embodiment, as the charger 4, a quick charger having a power conversion function of converting three - phase AC power supplied from the commercial power system 5 into DC power is assumed. The charger 4 performs full - wave rectification on the AC power supplied from the commercial power system 5 and generates DC power by smoothing using a filter.

[0065] Before starting the charging of the first battery pack 51 - the eighth battery pack 58, the power control unit 70 controls the DC / DC converter 60 to charge the reserve battery pack 59 in order to prevent inrush current. Then, the power control unit 70 closes the first switch S11 and the second switch S21 to charge the first battery pack 51 from the charger 4. At this time, the reserve battery pack 59 functions as a smoothing capacitance for the charging voltage.

[0066] When the charging of the first battery pack 51 is completed, the power control unit 70 opens the first switch S11 and the second switch S21, and then closes the first switch S12 and the second switch S22 to charge the second battery pack 52 from the charger 4. Similarly hereinafter, the charging is performed in sequence until the eighth battery pack 58.

[0067] In addition, the power control unit 70 can also control all of the first 1.1 switch S11 - the first 1.8 switch S18 and the second 2.1 switch S21 - the second 2.8 switch S28 to the on state, and charge the first battery pack 51 - the eighth battery pack 58 simultaneously. In addition, charging can be performed sequentially every two, or sequentially every four. At the same time, the number of rechargeable battery packs depends on the specifications of the components of the power supply system.

[0068] In addition, when the charger 4 is a normal charger, generally, charging is performed with single-phase 100 / 200V AC power. When charging with AC, an AC / DC converter (not shown) is inserted into the current path between the coupling point N9 and the charging port P1. The AC / DC converter converts the AC power input from the charger 4 into DC power and outputs it to the coupling point N9.

[0069] Figure 7 It is a diagram showing an example of the state of the power supply system during the flight of the flying object 1. As described above, when the flying object 1 moves forward, it is necessary to increase the rotational speeds of the fifth motor 25 - the eighth motor 28 more than the rotational speeds of the first motor 21 - the fourth motor 24. In addition, when the flying object 1 moves forward to the left front, it is necessary to increase the rotational speeds of the seventh motor 27 - the eighth motor 28 more than the rotational speeds of the first motor 21 - the sixth motor 26.

[0070] Figure 7 It shows an example of the state of the power supply system when the flying object 1 moves forward to the left front. When the flying object 1 moves forward to the left front, it is necessary to increase the rotational speeds of the seventh motor 27 - the eighth motor 28, so the power consumption of the seventh motor 27 - the eighth motor 28 is greater than the power consumption of the first motor 21 - the sixth motor 26. That is, the load of the seventh motor 27 - the eighth motor 28 is greater than the load of the first motor 21 - the sixth motor 26. In this case, the SOC of the seventh battery pack 57 - the eighth battery pack 58 decreases faster than the SOC of the first battery pack 51 - the sixth battery pack 56.

[0071] In Figure 7 In the example shown, the power control unit 70 controls the first 1.7 switch S17 - the first 1.8 switch S18 inserted in the second current path connected to the seventh motor 27 - the eighth motor 28 with a greater power consumption than the first motor 21 - the sixth motor 26 to the on state, and maintains the first 1.1 switch S11 - the first 1.6 switch S16 inserted in the second current path connected to the first motor 21 - the sixth motor 26 in the off state. Thereby, auxiliary current is supplied only to the seventh motor 27 - the eighth motor 28 from the reserve battery pack 59, and the decrease in the SOC of the seventh battery pack 57 - the eighth battery pack 58 is alleviated.

[0072] Next, the on / off control of the first switch inserted in the second current path connected to the motor with higher power consumption will be specifically described. Basically, the following processing is executed in a state where the deviation of the power consumption of the first battery pack 51 - the eighth battery pack 58 exceeds a specified value.

[0073] Based on the respective current values of the first battery pack 51 - the eighth battery pack 58 received from the first battery pack 51 - the eighth battery pack 58, the power supply control unit 70 determines at least one battery pack with a current value higher than others. The power supply control unit 70 calculates the over-current value of the determined battery pack. In Figure 7 the example shown, the power supply control unit 70 sums up the over-current values of the seventh battery pack 57 and the eighth battery pack 58 to calculate the overall over-current value. The power supply control unit 70 determines the current command value of the DC / DC converter 60 so that the output current value of the DC / DC converter 60 is this over-current value. The power supply control unit 70 sets the determined current command value to the DC / DC converter 60 to operate the DC / DC converter 60, and turns on the first 1.7 switch S17 - the first 1.8 switch S18. If the deviation of the respective current values of the first battery pack 51 - the eighth battery pack 58 converges within the specified value, the power supply control unit 70 stops the DC / DC converter 60 and turns off the first 1.7 switch S17 - the first 1.8 switch S18.

[0074] In addition, the power supply control unit 70 may execute the on / off control of the first switch as follows. The power supply control unit 70 obtains the respective rotational speeds of the first motor 21 - the eighth motor 28 from the body control unit 40. Based on the obtained respective rotational speeds, the power supply control unit 70 determines at least one battery pack with a rotational speed higher than others. The power supply control unit 70 calculates the over-current value corresponding to the over-rotational speed of the determined battery pack. In Figure 7 the example shown, the power supply control unit 70 sums up the over-current value of the seventh battery pack 57 and the over-current value of the eighth battery pack 58 to calculate the overall over-current value. Next, it is the same as the above processing.

[0075] In addition, the power control unit 70 can also perform on / off control of the first switch as described below. The power control unit 70 determines at least one battery pack with a voltage value smaller than others based on the voltage values received from the first to eighth battery packs 51-58. The power control unit 70 determines the voltage command value of the DC / DC converter 60 so that the output voltage value of the DC / DC converter 60 is higher than the voltage value of the determined battery pack. The power control unit 70 sets the determined voltage command value to the DC / DC converter 60 to operate the DC / DC converter 60, and turns on the first 1.7 switch S17 - the first 1.8 switch S18. If the deviation of the voltage values or SOC of the first to eighth battery packs 51-58 converges within a specified value, the power control unit 70 stops the DC / DC converter 60 and turns off the first 1.7 switch S17 - the first 1.8 switch S18.

[0076] Figures 8 - 10 FIG. is an example for explaining the equalization process of the capacities among the first to eighth battery packs 51-58 during the shutdown of the flying object 1. In this example, it is assumed that the flying object 1 is temporarily shut down at a place where the charger 4 does not exist. During the temporary shutdown of the flying object 1, the power control unit 70 equalizes the capacities among the first to eighth battery packs 51-58 by the active balancing method.

[0077] For example, the power control unit 70 calculates the average value of the voltages of the first to eighth battery packs 51-58 received from the first to eighth battery packs 51-58, and sets the calculated average value as the equalization target voltage (hereinafter, simply referred to as the target voltage).

[0078] The power control unit 70 causes energy to move from the battery pack with a voltage higher than the target voltage ( Figure 8 in this case, it is the first battery pack 51) to the battery pack with a voltage lower than the target voltage ( Figure 8 in this case, it is the third battery pack 53). First, as Figure 9 shown, the power control unit 70 controls the first 1.1 switch S11 and the second 1.1 switch S21 to the on state, and charges the reserve battery pack 59 from the first battery pack 51 until the voltage of the first battery pack 51 drops to the target voltage. When the voltage of the first battery pack 51 is lower than the voltage of the reserve battery pack 59, the power control unit 70 controls the DC / DC converter 60 to boost the voltage of the first battery pack 51.

[0079] Next, as Figure 10As shown, the power control unit 70 controls the first 1.3 switch S13 and the second 2.3 switch S23 to the on state, and charges the third battery pack 53 from the reserve battery pack 59 so that the voltage of the third battery pack 53 rises to the target voltage. When the voltage of the reserve battery pack 59 is lower than the voltage of the third battery pack 53, the power control unit 70 controls the DC / DC converter 60 to boost the voltage of the reserve battery pack 59.

[0080] The power control unit 70 repeatedly executes the above process until the voltages of the first battery pack 51 - the eighth battery pack 58 are all equalized. In the above description, an example of using voltage as the equalization target value is described, but instead of voltage, SOC, actual capacity, dischargeable capacity, or chargeable capacity can be used.

[0081] Even when there is no substantial capacity deviation among the first battery pack 51 - the eighth battery pack 58, when the SOC of the first battery pack 51 - the eighth battery pack 58 drops below the set value, the power control unit 70 can charge the first battery pack 51 - the eighth battery pack 58 from the reserve battery pack 59.

[0082] However, a malfunction may occur in at least one of the first battery pack 51 - the eighth battery pack 58. If the current supply to the corresponding motor from the battery pack with the malfunction stops, the attitude control of the flying object 1 becomes difficult. In response, the power control unit 70 controls the second switch inserted in the first current path connected to the battery pack with the malfunction to the off state, and controls the first switch inserted in the second current path connected to the battery pack to the on state. Thereby, the current supply from the reserve battery pack 59 to the motor can be continued. That is, the reserve battery pack 59 functions as a battery pack replacing the battery pack with the malfunction.

[0083] In the present embodiment, the rated output of the reserve battery pack 59 is designed to be a value corresponding to the rated outputs of the first battery pack 51 - the eighth battery pack 58. As described above, since the reserve battery pack 59 is sometimes used as a replacement for at least one of the first battery pack 51 - the eighth battery pack 58, it is necessary to have output performance equivalent to that of the first battery pack 51 - the eighth battery pack 58.

[0084] The capacity of the reserve battery pack 59 is designed to be smaller than that of the first to eighth battery packs 51-58. From the viewpoints of ensuring the reserve capacity and the buffer area, it is desirable for the capacity of the reserve battery pack 59 to be larger. However, if the capacity of the reserve battery pack 59 becomes large, the reserve battery pack 59 becomes heavy, which is an important factor reducing the power utilization rate of the flying object 1. In the present embodiment, giving priority to the power utilization rate of the flying object 1, the capacity of the reserve battery pack 59 is designed to be smaller than that of the first to eighth battery packs 51-58.

[0085] As described above, according to the present embodiment, by designing the plurality of battery packs 51-58 and the reserve battery pack 59, even if any one of the battery packs malfunctions during flight, by switching the malfunctioning battery pack to the reserve battery pack 59, stable flight can be continued. Therefore, the safety during flight can be improved, which also contributes to the practical use of the manned unmanned aerial vehicle.

[0086] In addition, by disposing the reserve battery pack 59 at the center of gravity of the airframe, the weight of the airframe can be made uniform in the front-back, left-right directions. Thereby, it is possible to prevent the attitude of the airframe from becoming an unstable point. In addition, it is possible to prevent the load from being biased to a specific motor, and it is possible to prevent the SOH of a specific battery pack from decreasing faster than others.

[0087] In addition, as Figure 1 shown, when the reserve battery pack 59 is disposed at the center of the airframe, the power wirings connecting the reserve battery pack 59 to the first to eighth battery packs 51-58 can be made uniform and shortest. By making the power wirings uniform, the wiring resistances are equal, and the voltage drops caused by the wiring resistances become uniform among the first to eighth battery packs 51-58. Thereby, the accuracy of voltage measurement of the first to eighth battery packs 51-58 is improved, and the accuracy of equalization per unit time is also improved.

[0088] In addition, as Figure 3 shown, even when the reserve battery pack 59 is disposed at a position deviated from the center of the airframe, the reserve battery pack 59 can be connected to the first to eighth battery packs 51-58 so that the wiring resistances are equal, thereby obtaining the same effects as described above.

[0089] In addition, by disposing the substrate carrying the electrical components (relays, etc.) of the power supply system near the reserve battery pack 59, the wiring resistances between the reserve battery pack 59 and the first to eighth battery packs 51-58 can be made more strictly uniform. In addition, due to the weight of the substrate, the adverse effects on the balance of the airframe can be prevented.

[0090] In addition, by supplying auxiliary current from the reserve power storage unit 59 to the motor with a high rotational speed during flight, it is possible to suppress the deviation in the reduction of the SOC between the first power storage units 51 to the eighth power storage units 58. As a result, it is possible to equalize the number of charge-discharge cycles between the first power storage units 51 to the eighth power storage units 58, and it is possible to suppress the deviation in the reduction of the SOH between the first power storage units 51 to the eighth power storage units 58. Therefore, it is possible to make the replacement periods of the first power storage units 51 to the eighth power storage units 58 consistent, which also helps to reduce the operating cost of the power storage units.

[0091] In addition, during the temporary stop of the flying object 1, by equalizing the capacities between the first power storage units 51 to the eighth power storage units 58 by an active balancing method, it is possible to maximize the effective use of the capacities of the first power storage units 51 to the eighth power storage units 58. That is to say, it is possible to suppress the actual flight distance from being shorter than the flyable distance that could originally be flown by the total capacities of the first power storage units 51 to the eighth power storage units 58. In addition, by effectively using the reserve power storage unit 59 as a buffer, it is possible to effectively perform the equalization of the active balancing method. Since the remaining capacity in the equalization of the active balancing method can be charged to the reserve power storage unit 59, it is possible to effectively use it without discarding the remaining capacity as in the passive balancing method.

[0092] During the equalization process of the active balancing method, charging is performed from the power storage unit with a high SOC to the power storage unit with a low SOC via the DC / DC converter 60 and the reserve power storage unit 59. As a result, even if DC / DC converters are not separately connected to the first power storage units 51 to the eighth power storage units 58, it is possible to appropriately control the equalization current. During the equalization process of the active balancing method, it is also possible to suppress the inrush current from flowing from the power storage unit with a high SOC to the power storage unit with a low SOC. Therefore, safety can be ensured and costs can be reduced.

[0093] In addition, by coupling the first power storage units 51 to the eighth power storage units 58 to a plurality of busbars connecting the reserve power storage unit 59 respectively and externally charging the coupling points N9 of the plurality of busbars, it is possible to simplify the charging operation of the first power storage units 51 to the eighth power storage units 58. If the first power storage units 51 to the eighth power storage units 58 are externally charged separately, the operation of inserting the charging cable 4a occurs 8 times, but in this embodiment, one operation is sufficient. In addition, since the reserve power storage unit 59 can function as a smoothing capacity during charging, it is possible to suppress the inrush current at the start of charging.

[0094] As described above, the present disclosure has been described based on the embodiments. The embodiments are illustrative, and those skilled in the art can understand that various modifications can be made to the combination of each structural element and each processing step, and these modifications are also within the scope of the present disclosure.

[0095] For example, the first to eighth power storage units 51-58 may also be configured to be detachable from the airframe. In this case, the power storage unit can be removed from the airframe and charged. In addition, it is also possible to replace it with the same type of power storage unit that has finished charging. In this case, charging time can be saved.

[0096] In addition, in the above-described embodiment, an example in which the reserve power storage unit 59 is provided at the center of gravity of the flying object 1 has been described. In this regard, in order to adjust the position of the center of gravity in the front-rear direction on the left-right center line L1 of the flying object 1, the reserve power storage unit 59 can also be used. For example, in order to shift the center of gravity position in a state where the reserve power storage unit 59 is not provided forward, the reserve power storage unit 59 may be provided at a position more forward than the center of gravity position in a state where the reserve power storage unit 59 is not provided. Similarly, in order to shift the center of gravity position in a state where the reserve power storage unit 59 is not provided backward, the reserve power storage unit 59 may be provided at a position more backward than the center of gravity position in a state where the reserve power storage unit 59 is not provided.

[0097] In addition, in the above-described embodiment, the flying object 1 having eight propellers 11-18 has been described. In this regard, the number of propellers is not limited to eight. For example, the number of propellers can be four, six, or twelve.

[0098] In addition, the embodiment may also be determined by the following items.

[0099] [Item 1]

[0100] An aircraft (1) comprising a main body (2) and a plurality of propellers (11-18) radially arranged symmetrically left and right from the main body (2), characterized in that the aircraft (1) comprises:

[0101] A plurality of motors (21-28) for rotating the plurality of propellers (11-18) respectively;

[0102] A plurality of power storage units (51-58) for supplying current to the plurality of motors (21-28) respectively; and

[0103] A reserve power storage unit (59) connected to the plurality of power storage units (51-58) respectively through power wirings (H11-H18),

[0104] The plurality of motors (21-28) are provided in the same number on the left and right, and the plurality of power storage units (51-58) are provided in the same number on the left and right,

[0105] The reserve power storage unit (59) is provided on the left-right center line of the main body (2).

[0106] Accordingly, it is possible to suppress the influence on the body balance and effectively utilize the capacities of the plurality of storage batteries (51 - 58).

[0107] [Item 2]

[0108] In the flying object (1) described in Item 1, it is characterized in that the reserve storage battery (59) is provided at the center of gravity of the flying object (1).

[0109] Accordingly, it is possible to suppress the adverse influence on the body balance caused by the provision of the reserve storage battery (59).

[0110] [Item 3]

[0111] In the flying object (1) described in Item 1 or 2, it is characterized in that the reserve storage battery (59) and the plurality of storage batteries (51 - 58) are respectively connected by power wirings (H11 - H18) so that the respective wiring resistances between the reserve storage battery (59) and the plurality of storage batteries (51 - 58) are equal.

[0112] Accordingly, it is possible to improve the accuracy of voltage measurement of the plurality of storage batteries (51 - 58).

[0113] [Item 4]

[0114] In the flying object (1) described in any one of Items 1 to 3, it is characterized in that the plurality of storage batteries (51 - 58) are dispersedly arranged at equal distances from the center line on the left and right of the main body portion (2).

[0115] The power wirings (H11 - H18) respectively connecting the reserve storage battery (59) and the plurality of storage batteries (51 - 58) are set to be of equal length.

[0116] Accordingly, it is possible to suppress the influence on the body balance and make the wiring resistances of the power wirings (H11 - H18) consistent.

[0117] [Item 5]

[0118] In the flying object (1) described in any one of Items 1 to 4, it is characterized in that the capacity of the reserve storage battery (59) is less than the capacities of the plurality of storage batteries (51 - 58).

[0119] Accordingly, it is possible to suppress the increase in the weight of the flying object (1) and suppress the reduction in the power utilization rate of the flying object (1).

[0120] -Symbol Explanation-

[0121] 1 Flying object, 2 Main body, 11 - 18 Propellers, 21 - 28 Motors, A1 - A4 Arms, X1 - X4 Shafts, H1 - H8, H11 - H18 Wiring harnesses, 31 - 38 Motor drive units, 40 Airframe control unit, 41 Sensors, 51 - 58 Batteries, 59 Backup battery, 511 Battery module, E1 - En Units, Rs Shunt resistor, T1 Temperature sensor, 512 Control board, 513 Voltage measurement unit, 514 Temperature measurement unit, 515 Current measurement unit, 516 Management unit, 60 DC / DC converter, 70 Power control unit, 71 Communication line, S11 - S18 First switch, S21 - S28 Second switch, P1 Charging port, 4 Charger, 4a Charging cable, 5 Commercial power system.

Claims

1. A flying object, comprising: a main body and a plurality of propellers radially arranged symmetrically on the left and right of the main body, and the flying object comprises: A plurality of motors that rotate the plurality of propellers respectively; A plurality of storage batteries that supply current to the plurality of motors respectively; A standby storage battery that is connected to the plurality of storage batteries respectively through power wirings; A plurality of switches that are respectively arranged between the plurality of storage batteries and the standby storage battery; And A power control unit that controls the plurality of switches, The same number of the plurality of motors are arranged on the left and right respectively, and the same number of the plurality of storage batteries are arranged on the left and right respectively, The standby storage battery is arranged on the center line of the left and right of the main body, During the flight of the flying object, the power control unit performs the following operations: Determine at least one storage battery, where the at least one storage battery is a storage battery with a current value greater than other storage batteries, or a storage battery that supplies current to a motor with a rotation speed greater than other motors; Turn on at least one switch corresponding to the at least one storage battery among the plurality of switches to supply auxiliary current from the standby storage battery to the at least one storage battery.

2. The flying object according to claim 1, Wherein, The standby storage battery is arranged at the center of gravity of the flying object.

3. The flying object according to claim 1 or 2, Wherein, The standby storage battery and the plurality of storage batteries are respectively connected through power wirings so that the wiring resistances between the standby storage battery and the plurality of storage batteries are equal.

4. The flying object according to claim 1 or 2, Wherein, The plurality of storage batteries are dispersedly arranged at equal distances from the center line on the left and right of the main body, The power wirings respectively connecting the standby storage battery and the plurality of storage batteries are set to be of equal length.

5. The flying object according to claim 1 or 2, Wherein, The capacity of the standby storage battery is less than the capacity of the plurality of storage batteries.

Images