JP2019048634A - Electric aircraft - Google Patents

Abstract

To reduce a weight of an electric aircraft.SOLUTION: An electric aircraft includes a plurality of rotary wings, motors for rotating the rotary wings respectively, support shafts for supporting the rotary wings and the motors respectively, motor control parts for controlling rotation of the motors, a plurality of power supply lines for supplying power to each pair of motors, and a plurality of battery modules provided at positions lower than positions of the support shafts, which are connected to each power supply line. When a length from the center of the support shaft to a central position of the rotary wing is represented by (a), a difference between the position of the support shaft and the position of the battery module is set to be in a range of (a/4) to (a/2).SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a rotary wing aircraft (multicopter) having two or more rotary wings, and in particular to a motorized aircraft.

  An unmanned aerial vehicle, which is one of the electric powered aircrafts of this type, is called a drone or the like, and rotates a motor by a battery module including a secondary battery and a battery control circuit, and rotates a rotor by a motor. The For example, Patent Document 1 describes an unmanned aerial vehicle having rotary wings. Conventional unmanned aerial vehicles have been relatively light such as toys. In recent years, the demand for carrying heavy luggage and the like has been increasing.

Unexamined-Japanese-Patent No. 2010-120641

  When carrying heavy loads, power shortages and in-flight balance have been a problem. The lack of power limits the flight time and the weight of cargo carried, and there is a problem that commercial unmanned aerial vehicles are not popularized. In order to compensate for the power shortage, a battery module having a large output is used. For example, a large number of cylindrical lithium ion secondary batteries such as 100 or more are used to achieve high power. Furthermore, it is very difficult to maintain the balance in the air, and the fact that the balance is broken and dropped due to the influence of wind and the like is also a reason for the widespread use of unmanned aerial vehicles for carrying luggage.

  The heavier the load, the larger and heavier the drive motor and propeller. And the battery module side corresponding to it is also necessary to set it as the electric configuration for large currents. Furthermore, there is a problem that the weight becomes heavy in order to configure an airframe corresponding to dropping, vibration and the like.

  Therefore, an object of the present disclosure is to provide a motorized aircraft that is easy to maintain balance in flight and that is easy to control the airframe.

The present disclosure provides a plurality of rotors,
A motor for rotating the rotary wings respectively;
A support shaft supporting the rotor and the motor respectively;
A motor control unit that controls the rotation of the motor;
A plurality of power supply lines for supplying power to each pair of motors;
And a plurality of battery modules attached below the position of the support shaft and connected to each of the power supply lines,
When the length from the center of the support shaft to the center position of the rotor is a, the difference between the position of the support shaft and the position of the battery module is set in the range of (a / 4) to (a / 2) Electric powered aircraft.

  According to at least one embodiment, it is possible to obtain a restoring force by the mass of the battery unit by the above-described positional relationship. That is, gravity is applied to the mass of the battery unit, so that a force is applied in a direction to keep the support shaft horizontal about the fulcrum. At the same time, it is possible to prevent the required motor output in the case of control to tilt the machine from becoming too large. In addition, the effect described here is not necessarily limited, and may be any effect described in the present invention. Further, the contents of the present invention are not interpreted as being limited by the effects illustrated in the following description.

FIG. 1 is a plan view showing the configuration of an unmanned aerial vehicle according to a first embodiment of the present disclosure. It is a front view which shows the structure of an unmanned aerial vehicle. It is a basic diagram used for explanation of an example of composition of a battery part, and other examples. It is a graph for explaining the present disclosure. FIG. 1 is a block diagram of a first embodiment of the present disclosure. It is a block diagram showing a modification of a 1st embodiment of this indication. It is a block diagram of 2nd Embodiment of this indication. It is a block diagram showing a modification of a 2nd embodiment of this indication. It is a block diagram of a reference example.

The embodiments described below are preferred embodiments of the present disclosure, and have various technically preferable limitations. However, the scope of the present disclosure is not limited to these embodiments unless specifically described in the following description to the effect that the present disclosure is limited.
The description of the present disclosure will be made in the following order.
<1. First embodiment>
<2. Second embodiment>
<3. Modified example>

<1. First embodiment>
FIG. 1 is a plan view of the unmanned aerial vehicle according to the first embodiment, and FIG. 2 is a front view of the unmanned aerial vehicle according to the first embodiment. An airframe is constituted by a cylindrical or rectangular cylindrical body portion 1 as a central portion, and support shafts 2a to 2f fixed to an upper portion of the body portion 1. As an example, the body portion 1 has a hexagonal cylindrical shape, and six support shafts 2a to 2f radially extend from the center of the body portion 1 at equal angular intervals. The body portion 1 and the support shafts 2a to 2f are made of a lightweight and strong material.

  Furthermore, the shape, arrangement, and the like of each component are designed such that the center of gravity of the airframe including the body portion 1 and the support shafts 2a to 2f is on a vertical line passing through the centers of the support shafts 2a to 2f. Furthermore, the circuit unit 5 and the battery unit 6 are attached such that the center of gravity is on the vertical line.

  In the first embodiment, the number of rotors and motors is six. However, the configuration may have four rotors and a motor, or may have eight or more rotors and a motor.

  Motors 3a to 3f as drive sources for the rotary wings are attached to tip ends of the support shafts 2a to 2f, respectively. The rotary wings 4a to 4f are attached to the rotation shafts of the motors 3a to 3f. A circuit unit 5 including a motor control circuit for controlling each motor is attached to a central portion where the support shafts 2a to 2f intersect.

  Furthermore, a battery unit 6 as a power source is disposed at a lower position of the body unit 1. The battery unit 6 has three battery modules so as to supply power to a motor and rotor pair having an opposing distance of 180 degrees, as described later. Each battery module has, for example, a lithium ion secondary battery and a battery control circuit that controls charging and discharging. That is, the motor 3a and the rotary wing 4a, and the motor 3d and the rotary wing 4d constitute a pair. Similarly, (Motor 3b, Rotor 4b) and (Motor 3e, Rotor 4e) form a pair, and (Motor 3c, Rotor 4c) and (Motor 3f, Rotor 4f) form a pair . The pairs are equal in number to the battery modules.

  The battery unit 6 can be detachably attached to, for example, the inside of the body unit 1. As shown in FIG. 3, the battery unit 6 has a symmetrical shape with respect to the center which is the center of gravity of the airframe, and has an arrangement and an outer shape so as to have the central opening 7. FIG. 3A is an example in which a hollow case 8 having a regular hexagonal shape is provided around the central opening 7 and the battery module is housed in the case 8. As shown in FIG. 3B, the battery module may be housed in separate cases 8a and 8b.

  By matching the center of gravity of the battery unit 6 with the center of gravity of the vehicle, the stability of the center of gravity is increased. Furthermore, since the central opening 7 is provided, the wind can pass through the central opening 7 at the time of flight, thereby reducing the influence of the wind and the like. As a result, attitude control becomes easy, flight time can be lengthened, and further, temperature rise of the battery can be suppressed.

  The battery unit 6 is disposed at a position lower than the horizontal position of the support shafts 2a to 2f, as shown in FIG. The position of the battery unit 6 is lowered by a distance of a / 4 to a / 2 with respect to the horizontal position. Here, a is the distance from the center position b of the airframe (the intersection of the support shafts 2a to 2f) to the rotation center of the rotary wings 4a to 4f. With such a positional relationship, the restoring force can be obtained by the mass of the battery unit 6. That is, the gravity applied to the mass of the battery unit 6 applies a force in a direction in which the support shaft is horizontal with the fulcrum b as a center. At the same time, it is possible to prevent the required motor output in the case of control to tilt the machine from becoming too large.

  FIG. 4 shows the restoring force and the motor output (vertical axis) required for forward inclination when the position of the battery unit 6 is taken as the horizontal axis. In order to make the graph easy to see, the restoring force is indicated by a linear axis, and the motor output for tilting is indicated by a logarithmic axis. For example, in the case where the battery unit 6 is installed at the a / 4 position as compared with the case where the battery unit 6 is installed at the a / 8 position, a restoring force of 2 times can be obtained by the lever principle, so the posture is stable. In order to secure the property, it is preferable that the battery pack be separated from the fulcrum b.

  On the other hand, in order for the unmanned aerial vehicle to move forward, the airframe needs to be in a forward-tilted position, so for example, when the battery unit 6 is installed at the position a, restoration is doubled compared to when installed at a / 2. It is necessary to have the force to lean forward against the force. For this reason, there is a problem that the output of the motor increases and the battery module for supplying power to the motor becomes large. From such a relationship, the installation position of the battery unit 6 is (a / 4 to a / 2) in order to improve the balance between the restoring force by the battery unit 6 and the motor output for turning the machine forward. It is.

  In an unmanned aerial vehicle generally called a drone, the motor control circuit controls the output of the motor to enable desired navigation. For example, in the hovering state where it is stationary in the air, the inclination is detected using a gyro device mounted on the airframe, and the motor output on the lower side of the airframe is increased and the motor output on the higher side is decreased. By doing so, the aircraft is kept horizontal. Further, at the time of forward movement, the motor output in the forward direction is reduced and the motor output in the reverse direction is increased, so that the forward lean posture is taken and propulsive force in the forward direction is generated. In such attitude control and propulsion control of an unmanned aerial vehicle, the installation position of the battery unit 6 as described above can balance the stability of the airframe and the ease of control.

  Furthermore, in these controls, in the pair of motor and rotor located at the opposing position of 180 degrees, there is a large relation that one rotation speed and the other rotation speed are controlled in opposite directions. In view of this point, the present disclosure provides a battery module that supplies power pair by pair.

  FIG. 5 shows a configuration example of a system according to the first embodiment of this disclosure. The battery unit 6 has three battery modules 11ad, 11be, 11cf. These battery modules 11ad, 11be, 11cf constitute a battery unit 6. As described above, the battery modules 11ad, 11be, 11cf are shaped to have the central opening 7.

  The output power of the battery module 11ad is supplied to the motor control circuit 12ad. Motors 3a and 3d are connected to motor control circuit 12ad. The motors 3a, 3d rotate the rotary wings 4a, 4d. The output power of the battery module 11be is supplied to the motor control circuit 12be. Motors 3b and 3e are connected to motor control circuit 12be. The motors 3b and 3e rotate the rotary wings 4b and 4e. The output power of the battery module 11cf is supplied to the motor control circuit 12cf. The motors 3c and 3f are connected to the motor control circuit 12cf. The motors 3c, 3f rotate the rotary wings 4c, 4f.

  Furthermore, although omitted in FIG. 5 and the following figures, an overall controller for controlling the entire unmanned aerial vehicle, an attitude sensor for detecting attitude, and the like are provided, and raising, lowering, advancing, retreating, etc. may be performed. It is made to be able.

  For example, in the unmanned aerial vehicle of FIG. 1, since there are three opposing sets of motors, three sets of components are provided, each consisting of a battery module, a motor control circuit, and an opposing motor. A reference example of such a system configuration different from the present disclosure is shown in FIG. For example, the output power of one battery module 15 is supplied to the motor control circuit 16, and the motor control circuit 16 distributes the power to the six motors 3a to 3f. Further, the motor control circuit 16 is configured to distribute power to the six motors 3a to 3f. There is also a case of a configuration of three battery modules in which the battery modules 15 are connected in parallel.

  In the configuration of the reference example shown in FIG. 9, power from the battery module 15 is supplied to six motors. Therefore, the current supplied from the battery module 15 to the motor control circuit 16 becomes a large value. Furthermore, the current flowing in the motor control circuit 16 becomes a large value. Cables, circuit parts and the like that can handle large currents are generally large and heavy, which increases the weight of the unmanned aerial vehicle.

  In the first embodiment of the present disclosure, the current supplied from each battery module to the motor control circuits 12ad, 12be, 12cf can be set to about 1⁄3 of the configuration of the reference example. As a result, the allowable current value can be set low for members and circuit components of the current path, and the weight of the system can be reduced. As a result, the weight of the unmanned aerial vehicle can be reduced.

  Furthermore, in an unmanned aerial vehicle, as described above, in the case of increasing the rotational speed of one of the pair of rotary blades facing each other at 180 degrees, the rotary blades (motors) in the opposite direction so as to decrease the rotational speed of the other. Are often controlled. Therefore, if power is supplied to the pair of motors from the common battery module, the reduction in capacity can be averaged among the battery modules corresponding to the plurality of pairs.

  FIG. 6 shows a system configuration of a modification of the first embodiment of the present disclosure. Compared with FIG. 5, the point which has provided the capacity | capacitance equalizing circuit 13 with respect to battery module 11ad, 11be, 11cf is different. The capacity equalizing circuit 13 includes circuits for monitoring the voltages of the battery modules 11ad, 11be, 11cf, and switching elements for equalizing the capacities among the battery modules 11ad, 11be, 11cf based on the voltage relationship. Have. For example, even if the center of gravity of an unmanned aerial vehicle is designed at the center position of a plurality of rotary wings, if the center of gravity of the mounted object is not at the center position, the load on a specific motor increases for attitude control. The capacity of the battery module to be driven is extremely reduced. As a result, the flight time may be shorter than expected. Such a problem can be avoided by the capacitance correction by the capacitance equalizing circuit 13.

<2. Second embodiment>
A second embodiment of the present disclosure will be described with reference to FIG. The configuration of the unmanned aerial vehicle is, as shown in FIG. 1, provided with six rotary wings 4a to 4f. In the first embodiment, while the motor control circuit is separated for each pair, in the second embodiment, control is performed for each pair, but in terms of the configuration, one motor control circuit 12 is used. And For example, in the motor control circuit 12, a microcomputer for control is shared by a plurality of pairs. The power supply system in the motor control circuit 12 is separated in each pair, and power is supplied to the pair of motors from each battery module through each power supply system.

  In the second embodiment, as in the first embodiment, power is supplied to a pair of motors from a common battery module, so that the capacity between battery modules corresponding to a plurality of pairs is obtained. Can be averaged out.

  Furthermore, by matching the center of gravity of the battery unit 6 with the center of gravity of the airframe, the stability of the center of gravity is increased. Furthermore, since the battery unit 6 has the central opening 7, attitude control is facilitated and flight time can be lengthened. Furthermore, by setting the position of the battery unit 6 to a position lower than the horizontal position of the support shafts 2a to 2f (a distance from a / 4 to a / 2), the restoring force by the battery unit 6 and the vehicle can be inclined forward. The balance with the motor output can be improved.

  FIG. 8 is a modification of the second embodiment. As in the first embodiment, a capacity equalizing circuit 13 for preventing a decrease in capacity of a specific battery module is configured in the motor control circuit 12.

<3. Modified example>
As mentioned above, although embodiment of this indication was described concretely, it is not limited to each above-mentioned embodiment, and various modification based on the technical idea of this indication are possible. For example, the present disclosure is applicable not only to the transportation of luggage but also to an electric aircraft equipped with imaging equipment and an electric aircraft for applications such as spraying of pesticides.

  Furthermore, the configurations, methods, processes, shapes, materials, numerical values, and the like of the above-described embodiments can be combined with one another without departing from the spirit of the present disclosure.

DESCRIPTION OF SYMBOLS 1 ... Body part 2a-2f ... Support shaft 3a-3f ... Motor 4a-4f ... Rotor wing 5 ... Circuit unit 6 ... Battery part 7 ... Central opening 11a-11f ... Battery modules 12a to 12f ... Motor control circuit

Claims (5)

With multiple rotors,
A motor for rotating the rotors respectively;
A support shaft supporting the rotor and the motor respectively;
A motor control unit that controls the rotation of the motor;
A plurality of power supply lines for supplying power to each pair of motors;
And a plurality of battery modules attached below the position of the support shaft and connected to each of the power supply lines,
The difference between the position of the support shaft and the position of the battery module is (a / 4) to (a / 2), where a is the length from the center of the support shaft to the center position of the rotor blade. Motorized aircraft designed to be set in range. Having a plurality of opposing pairs of rotors,
The motorized aircraft according to claim 1, wherein the plurality of pairs of rotors and the plurality of battery modules are equal in number.   The motorized aircraft according to claim 2, wherein the pair of rotors comprises rotors facing at 180 degrees.   The electric type aircraft according to any one of claims 1 to 3, further comprising a capacity equalizing circuit for equalizing the capacities of the plurality of battery modules.   The motorized aircraft according to any one of claims 1 to 4, wherein the plurality of battery modules are arranged to create a central opening.

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