Flapping wing device

Abstract

The invention provides a flapping wing device which is small in size and high in maneuverability. A flapping wing device (1) is provided with blades (2, 2) and a pair of drive units (3, 3) provided corresponding to the blades (2, 2). A drive unit (3) is provided with: a first drive source (30U); a second drive source (30D); a first driven unit (10U) that rotates about a first rotational axis by means of the first drive source (30U); a second driven unit (10D) that rotates about a second rotational axis by means of the second drive source (30D); a first urging member (40U) that urges the second driven part (10D); a second urging member (40D) that urges the second driven part (10D) in a direction opposite to the rotation direction of the second driven part (10D); and a control unit (60). The blade (2) has a first blade shaft (20) connected to the first driven part (10U) and capable of rotating about a third rotation axis intersecting the first rotation axis, a second blade shaft (21) connected to the second driven part (10D) and capable of rotating about a fourth rotation axis intersecting the second rotation axis, and a blade body (22).

Description

Technical Field

[0001] The present invention relates to a flapping-wing device that obtains lift by swinging blades. Background Art

[0002] Conventionally, a flapping-wing device has been used for surveillance, photographing, various inspections, etc. from above. As the above flapping-wing device, there is known a flapping-wing ultra-small aircraft system (hereinafter, simply referred to as a flapping-wing device) that directly drives a flapping wing (equivalent to a blade) by a DC motor. Since it is difficult to generate a high torque in the design of a DC motor as it is miniaturized, and the electro-mechanical energy conversion efficiency (hereinafter, simply referred to as efficiency) reaches a peak in the high-speed rotation (about 70 to 85% of the substantially no-load rotation speed) region, a flapping mechanism is mostly used. This flapping mechanism uses a link mechanism to convert a unidirectional rotational motion into a reciprocating rotational motion to flap the blade. On the other hand, in recent years, it has been found that a flapping stroke amplification mechanism using a resonance phenomenon is used in the flapping of organisms such as insects. Based on this insight, by constructing a resonance system using a torsion spring, it is possible to realize an airframe that can independently ascend even in a configuration using a small DC motor with a small torque (for example, Patent Document 1).

[0003] The flapping-wing device described in the above Patent Document 1 directly drives the blade by driving a DC motor connected to a torsion spring. In addition, the flapping-wing device described in the above Patent Document 1 considers exciting a spring-mass system composed of the restoring force of the torsion spring and the inertial force of the entire system (blade, driving force transmission system, rotor of the above DC motor) by reciprocating the rotational motion of the DC motor. It is shown in the above Patent Document 1 that when the excitation frequency of the DC motor is equal to the natural frequency of the above spring-mass system (2*π*√(K / I), where K is the spring constant of the torsion spring and I is the rotational inertia of the entire system), the driving efficiency of the motor reaches the maximum, and the flapping amplitude and lift also reach the maximum. That is, in this configuration, setting the flapping frequency to around the natural frequency of the above spring-mass system is beneficial for ascending. Therefore, in the case where the mass of the blade is large or the rotational inertia of the rotor of the motor is large, a torsion spring with a high spring constant is naturally used.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: US Patent Application Publication No. 2016 / 159477 Summary of the Invention

[0007] However, in recent years, with the diversification of the utilization of flapping devices, a small and highly maneuverable flapping device has been required. However, in the flapping device described in the above Patent Document 1, the drive of the blades is configured with a single degree of freedom. For example, the angle of attack of the blades cannot be changed independently of the stroke, and it is difficult to drive the blades with high precision. In addition, in the flapping device described in the above Patent Document 1, for example, when increasing the movement difference between the left and right blades (when generating a large posture control torque), it is necessary to increase the output of the motor.

[0008] In addition, when improving the maneuverability of the flapping device, it is possible to consider increasing the capacity of the motor, but there is a concern about the enlargement of the flapping device and the increase in cost. In addition, it is possible to consider increasing the spring constant of the torsion spring instead of increasing the capacity of the motor, thereby increasing the frequency involved in flapping. However, in the flapping device described in the above Patent Document 1, when increasing the spring constant of the torsion spring, there are concerns about affecting the movement in the yaw direction and about ensuring the stroke of the blades.

[0009] Therefore, an object of the present invention is to provide a small and highly maneuverable flapping device.

[0010] (1) The flapping device of the present invention provided to solve the above problems is characterized by having: a pair of blades; and a pair of drive units provided corresponding to the pair of blades respectively. The drive unit includes: a first drive source; a second drive source; a first driven part that rotates around a first rotation axis by receiving the power output from the first drive source; a second driven part that rotates around a second rotation axis by receiving the power output from the second drive source; a first biasing member that applies a force in a direction opposite to the rotation direction of the first driven part as the first driven part rotates; a second biasing member that applies a force in a direction opposite to the rotation direction of the second driven part as the second driven part rotates; and a control unit that controls the output of the driving forces of the first drive source and the second drive source. The blade has: a first blade shaft that extends in a predetermined axial direction, is connected to the first driven part at one end side, and is connected in a manner capable of rotating in a direction around a third rotation axis that intersects the first rotation axis; a second blade shaft that extends in a direction intersecting the first blade shaft, is connected to the second driven part at one end side, and is connected in a manner capable of rotating in a direction around a fourth rotation axis that intersects the second rotation axis; and a blade body that is provided across the first blade shaft and the second blade shaft.

[0011] The first blade shaft of the above flapping wing device is driven by a first drive source, and the second blade shaft is driven by a second drive source. That is, the blade is driven by both the first drive source and the second drive source. The stroke angle of the blade is defined by the rotation angle of the first drive source, and the angle of attack of the blade is defined by the difference between the rotation angles of the first drive source and the second drive source. Thus, the above flapping wing device can independently control the stroke and the angle of attack, and can achieve a more maneuverable flight such as moving horizontally while maintaining the posture.

[0012] Here, the first drive source and the second drive source (also collectively referred to as the drive source) can use various motors and the like, but it is preferable to use a brushless DC motor that is easy to reverse and has a high power-to-weight ratio. Thus, battery driving becomes easier, and control can also be easily performed.

[0013] In addition, the above flapping wing device can vibrate the first blade shaft and the second blade shaft in the direction around the first rotation axis and the direction around the second rotation axis by the biasing force of the first biasing member and the second biasing member (also collectively referred to as the biasing member). Therefore, the above flapping wing device can increase the flapping frequency of the pair of blades by vibration, and thus can drive the pair of blades at high speed. In addition, the biasing member is preferably a member such as a torsion spring that can apply a torque in the torsional direction.

[0014] Here, the inventors of the present invention and the like have conducted in-depth research and obtained the following insights: As long as the flapping frequency of the flapping wing device is increased, the influence of external disturbances can be reduced, and control also becomes easier. Based on the above insights, when increasing the flapping frequency, for example, it is possible to consider increasing the spring constant of the torsion spring or the like used for the biasing member. However, when the spring constant of the biasing member (for example, a torsion spring) is increased, the restoring force also becomes stronger, so the load becomes larger, and there is a concern that it is difficult to flap the blade shaft. As a result, there is a concern that the lift force is reduced.

[0015] In addition, for example, in order to move the flapping wing device in the pitching direction, it is necessary to shift the amplitude center of the first biasing member and the second biasing member to one side or the other side (hereinafter also referred to as the front-rear direction) in the direction around the first rotation axis and the direction around the second rotation axis. However, when shifting the flapping wing device in the front-rear direction, there is a problem that the restoring force of the biasing member makes the shift difficult. In addition, when the spring constant of the biasing member is increased, the restoring force becomes even stronger, so there is a problem that the shift becomes even more difficult. Therefore, there is a need for a flapping wing device that can increase the flapping frequency and make the control of the drive unit more stable.

[0016] (2) Therefore, the flapping wing device of the present invention provided to solve the above problems is characterized by having: a pair of blades; and a pair of drive units provided corresponding to the pair of blades respectively. The drive unit includes: a first drive source; a second drive source; a first driven part that rotates around a first rotation axis by receiving the power output from the first drive source; a second driven part that rotates around a second rotation axis by receiving the power output from the second drive source; a first biasing member that applies a force in a direction opposite to the rotation direction of the first driven part as the first driven part rotates; a second biasing member that applies a force in a direction opposite to the rotation direction of the second driven part as the second driven part rotates; and a control unit that controls the output of the driving forces of the first drive source and the second drive source. The blade has: a first blade shaft extending in a specified axis direction, connected to the first driven part at one end side, and connected in a manner capable of rotating in a direction around a third rotation axis, the third rotation axis intersecting the first rotation axis; a second blade shaft extending in a direction intersecting the first blade shaft, connected to the second driven part at one end side, and connected in a manner capable of rotating in a direction around a fourth rotation axis, the fourth rotation axis intersecting the second rotation axis; and a blade body provided across the first blade shaft and the second blade shaft. The first biasing member is connected to the first driven part at one end side and directly or indirectly connected to the first blade shaft at the other end side. The second biasing member is connected to the second driven part at one end side and directly or indirectly connected to the second blade shaft at the other end side.

[0017] In the above flapping wing device, one end side of the first biasing member is connected to the first driven part, and the other end side is directly or indirectly connected to the first blade shaft. In addition, in the above flapping wing device, one end side of the second biasing member is connected to the second driven part, and the other end side is connected to the second blade shaft. That is, one end sides of the first biasing member and the second biasing member (also collectively referred to as the biasing members) are not fixed to the fuselage constituting the flapping wing device, but are fixed to the first driven part and the second driven part. In other words, one end sides of the biasing members become free ends. Therefore, even when a torque (force) is applied to the biasing members, the above flapping wing device can vibrate the first blade shaft and the second blade shaft without being affected by the restoring force of the biasing members. That is, the above flapping wing device can directly apply a torque to the first blade shaft and the second blade shaft. Thereby, it is possible to expect the output control of the drive source to become stable. In addition, the above biasing members are preferably members such as torsion springs that can apply a torque in the torsion direction.

[0018] In addition, in the above flapping wing device, one end side of the biasing member is a free end. Therefore, even if the spring constant of the biasing member is increased, it is not easily affected by the restoring force of the biasing member. Thus, according to the above flapping wing device, the spring constant of the biasing member can be increased, thereby increasing the flapping frequency. Therefore, it is possible to expect the output control of the drive source to become stable. In addition, as the spring constant of the biasing member increases, the weight of the biasing member can be increased. Therefore, it is possible to expect a further reduction in the influence of external disturbances.

[0019] In addition, the first blade shaft of the above flapping wing device is driven by a first drive source, and the second blade shaft is driven by a second drive source. That is, the blade is driven by both the first drive source and the second drive source. The stroke angle of the blade is defined by the rotation angle of the first drive source, and the angle of attack of the blade is defined by the difference in the rotation angles of the first drive source and the second drive source. Thus, the above flapping wing device can independently control the stroke and the angle of attack, and can achieve more maneuverable flight such as moving horizontally while maintaining the posture.

[0020] Here, the first drive source and the second drive source (both are also collectively referred to as the drive source) can use various motors, etc., but it is preferable to use a brushless DC motor that is easy to reverse and has a high power-to-weight ratio. Thereby, battery driving becomes easier, and control can also be easily performed.

[0021] Here, for example, when the blade is formed in a fan shape, the second blade shaft is arranged in the direction of a fourth rotation axis that is inclined with respect to the third rotation axis of the first blade shaft. Therefore, the second blade shaft must be supported in such a way that it can rotate around the fourth rotation axis that intersects the first blade shaft. Therefore, the support portion of the second blade shaft is preferably inclined corresponding to the fourth rotation axis.

[0022] (3) Therefore, the flapping wing device of the present invention described above is characterized in that: it has a link member, and one end side of the link member is connected to the second driven part in such a way that it can rotate around a fifth axis, the fifth axis intersects the second rotation axis, the link member is formed such that the other end side extends toward the second blade shaft, and is connected to the second blade shaft in such a way that it can rotate around the fourth rotation axis.

[0023] By adopting this configuration in the above flapping wing device, even when the second blade shaft is inclined with respect to the first blade shaft (for example, when the blade is formed in a fan shape), the second blade shaft can be reliably supported in a rotatable manner according to the inclination direction (the direction of the fourth rotation axis). Thereby, it is possible to expect an increase in the design freedom and aerodynamic characteristics of the blade.

[0024] Here, when an inner rotor motor is used as a driving source, since the inertia generated by the rotor of the motor is small, the effect of the change in the inertia of the blades applied to the first blade shaft and the second blade shaft as the posture (angle of attack) of the blades changes becomes relatively large. Along with this, the resonant frequency also changes significantly, and then the resonance coefficient (amplification factor of the blade amplitude) also changes significantly. Therefore, the control of the blades needs to consider the change in the blade amplitude, and there is a problem of complicated control. Therefore, after further in-depth research, the inventors and others obtained the following insights: Compared with the inner rotor motor, when using an outer rotor motor with a large inertia generated by the rotor, the change in the inertia of the first blade shaft and the second blade shaft generated as the posture of the blades changes is relatively small compared to the large inertia of the rotor of the outer rotor motor. Therefore, the change in the resonant frequency of the resonance system and the change in the blade amplitude also become smaller, and control becomes easier.

[0025] (4) Therefore, the flapping-wing device of the present invention described above is characterized in that the first driving source and the second driving source are constituted by outer rotor motors among DC motors.

[0026] The flapping-wing device can reduce the cost of the first drive source and the second drive source by using an outer rotor motor that is cheaper than an inner rotor motor. Therefore, the flapping-wing device can be expected to further reduce costs by replacing four drive sources, namely, a pair of first drive sources and a pair of second drive sources, with outer rotor motors. In addition, the flapping-wing device can reduce changes in the resonant frequency of the resonant system and changes in the blade amplitude by using an outer rotor motor, and thus can be expected to further stabilize the control.

[0027] Here, the inventors and others have conducted in-depth research and obtained the following insights: In the above-mentioned flapping-wing device, the electrical and mechanical conversion efficiency of the driving part (such as a motor) tends to decrease when the reciprocating motion of the blade turns back (switching between reciprocating motion and reciprocating motion). In addition, in the above-mentioned flapping-wing device, the reciprocating motion of the blade is turned back autonomously at the turning end of the reciprocating motion of the blade by the restoring force of the first force applying member and the second force applying member. Therefore, it is believed that as long as the motor is stopped at the turning end of the reciprocating motion of the blade, the vibration is only performed in the area where the angular velocity of the blade is large near the center of the flapping motion, and the efficiency of the motor will be improved.

[0028] (5) Therefore, the above-mentioned flapping-wing device is characterized in that: the control unit performs the following control: the first drive source and the second drive source stop outputting driving force before a specified time when the rotation speeds of the first drive source and the second drive source become zero during the switching of the forward rotation or reverse rotation of the first drive source and the second drive source, and performs the following control: at the moment when the forward movement or reciprocating movement of the blade is switched by the restoring force of the first force applying component and the second force applying component, the first drive source and the second drive source resume outputting driving force.

[0029] The above flapping device is controlled as follows: before a specified time when the rotational speed of the drive source becomes zero during the forward or reverse rotation switching of the first drive source and the second drive source (hereinafter also simply referred to as the drive source), the drive source is stopped from driving. Thus, it is possible to stop driving by the drive source in the part where the efficiency of the drive source decreases. Therefore, it is possible to reduce the waste of the output of the drive source, and it is possible to expect an improvement in the power consumption rate of the drive battery. In this way, the above flapping device can efficiently reciprocate the blades. In addition, the above flapping device is controlled as follows: when the reciprocating or returning movement of a pair of blades is switched by the restoring force of the first biasing member and the second biasing member, the drive source restarts driving. Thus, the above flapping device can excite the blades in the region where the angular velocity of the blades near the center of flapping is large. In addition, the above flapping device can efficiently perform flapping motion without increasing the capacity of the drive source. Therefore, it is possible to expect miniaturization of the above flapping device.

[0030] (6) The flapping device of the present invention is characterized in that: the control unit can execute first offset control and second offset control. The first offset control offsets the amplitude center of the first biasing member by a specified amount to one side or the other side around the first rotation axis, and the second offset control offsets the amplitude center of the second biasing member by a specified amount to one side or the other side around the second rotation axis. The first offset control and the second offset control are executed by applying a specified amount of offset to the drive voltage waveforms of the first drive source and the second drive source.

[0031] The above flapping device can easily execute the first offset control and the second offset control by applying a specified amount of offset to the drive voltage waveforms of the first drive source and the second drive source. Therefore, according to the above flapping device, both high-precision control and stable control can be expected.

[0032] Here, in the above first offset control and second offset control, when one end side of the first biasing member and the second biasing member (also collectively referred to as the biasing member) is a free end, there is a concern that the amplitude center of the offset biasing member deviates from the predetermined amplitude center (also referred to as the reference position) as the biasing member vibrates.

[0033] (7) Therefore, the flapping wing device of the present invention is characterized in that: the flapping wing device has a fuselage that supports the pair of drive parts, and the flapping wing device has: a third biasing member that applies a force in a direction opposite to the rotation direction of the first driven part to the first driven part as the first driven part rotates; and a fourth biasing member that applies a force in a direction opposite to the rotation direction of the second driven part to the second driven part as the second driven part rotates. One end side of the third biasing member is connected to the fuselage, and the other end side is directly or indirectly connected to the first blade shaft. One end side of the fourth biasing member is connected to the fuselage, and the other end side is directly or indirectly connected to the second blade shaft. The third biasing member and the fourth biasing member are configured to be able to exert a force smaller than the forces of the first biasing member and the second biasing member, and to be able to exert a force that can return the amplitude centers of the first biasing member and the second biasing member to the reference position.

[0034] By adopting this configuration, even if one end side of the first biasing member and the second biasing member becomes a free end, the amplitude centers of the first biasing member and the second biasing member can be returned to the reference position (predetermined amplitude center). Therefore, according to the above flapping wing device, it is possible to expect further improvement in control accuracy and stability.

[0035] (8) The flapping wing device of the present invention is characterized in that: the control unit performs the following control: setting a phase difference between the outputs of the first drive source and the second drive source so that the blades are inclined by a predetermined angle in a direction opposite to the traveling direction.

[0036] By adopting this configuration, the flapping wing device can efficiently generate lift.

[0037] Here, when the first drive source and the second drive source use outer rotor motors, due to the rotation of the rotor in the outer peripheral part, there is a concern that the rotor may interfere with each part.

[0038] (9) Therefore, the flapping wing device of the present invention is characterized in that: the flapping wing device has a fuselage that supports the pair of drive parts, the fuselage has a pair of support parts arranged at intervals, the first drive source and the second drive source are arranged outside the pair of support parts, and the first biasing member, the second biasing member, the first driven part, and the second driven part are arranged between the pair of support parts.

[0039] With the above-described configuration of the flapping-wing device, the first drive source and the second drive source (also collectively referred to as the drive source) do not interfere with the first biasing member, the second biasing member, the first follower portion, and the second follower portion. Therefore, for example, when an external rotor motor is used as the drive source in the above-described flapping-wing device, interference between the rotor of the external rotor motor and the first biasing member, the second biasing member, the first follower portion, and the second follower portion can be suppressed. Thus, even when the rotor is exposed like an external rotor motor, the above-described flapping-wing device can suppress an increase in the size of the device.

[0040] (Advantages of the Invention)

[0041] According to the present invention, a flapping-wing device that is small-sized and capable of achieving high maneuverability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is an overall perspective view of the flapping-wing device according to the first embodiment of the present invention.

[0043] Figure 2 is a top view of the flapping-wing device according to the first embodiment of the present invention.

[0044] Figure 3 is a perspective view of the flapping-wing device according to the first embodiment of the present invention as viewed from the obliquely rear side.

[0045] Figure 4 is a perspective view of the flapping-wing device according to the first embodiment of the present invention as viewed from the rear side.

[0046] Figure 5 is a schematic cross-sectional view of a part of the flapping-wing device according to the first embodiment of the present invention.

[0047] Figure 6 is an explanatory view of the drive of the blade constituting the flapping-wing device according to the first embodiment of the present invention.

[0048] Figure 7 is an explanatory view of the output characteristics of the motor and the output region of the motor used in the flapping-wing device according to the first embodiment of the present invention.

[0049] Figure 8 In (a), it is an explanatory view of the case where the center of amplitude is shifted, and in (b), it is an explanatory view of the shift control in the flapping-wing device according to the first embodiment of the present invention.

[0050] Figure 9 is a schematic cross-sectional view of a part of the flapping-wing device according to the second embodiment of the present invention.

[0051] Figure 10 is an explanatory view of the shift control in the flapping-wing device according to the second embodiment of the present invention.

[0052] Figure 11 This is a schematic cross-sectional view of a flapping wing device according to the third embodiment of the present invention.

[0053] (Reference Signs)

[0054] 1: Flapping wing device

[0055] 2: Blade

[0056] 3: Driving part

[0057] 7: Airframe

[0058] 10U: First driven part

[0059] 10D: Second driven part

[0060] 20: First blade shaft

[0061] 21: Second blade shaft

[0062] 22: Blade body

[0063] 30: Driving source

[0064] 30U: First driving source

[0065] 30D: Second driving source

[0066] 40: Biasing member

[0067] 40U: First biasing member

[0068] 40D: Second biasing member

[0069] 41U: Third biasing member

[0070] 41D: Fourth biasing member

[0071] 53: Link member

[0072] 60: Control part

[0073] 70U: Support part

[0074] 70D: Support part

[0075] 70M: Intermediate support part

[0076] 100: Flapping wing device

[0077] 200: Flapping wing device Detailed implementation manners

[0078] Hereinafter, the flapping wing device 1 according to the first embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, these drawings are schematic views and do not necessarily show the sizes in the correct ratio. Also, it should be noted that the same reference numerals are assigned to the same components in the drawings. Also, as Figure 2 shown, the vertical direction in the drawing is set as the Z direction, the left - right direction is set as the X direction, the depth direction in the drawing is set as the Y direction, the rotation around the Z - axis direction is called the yaw direction, the rotation around the X - axis direction is called the pitch direction, and the rotation around the Y - axis direction is called the roll direction.

[0079] 《First Embodiment》

[0080] As Figures 1 to 5 shown, the flapping wing device 1 has a pair of blades 2, 2 and a pair of drive units 3, 3 (a total of four drive units 3, 3, 3, 3) provided respectively with respect to the pair of blades 2, 2. The drive units 3, 3, 3, 3 are respectively supported by the fuselage 7. The flapping wing device 1 in the present embodiment obtains lift force toward the upper side by reciprocally driving the pair of blades 2, 2 in the horizontal direction (the front - rear direction of the drawing plane). In addition, since the pair of blades 2, 2 and the four drive units 3, 3, 3, 3 are arranged symmetrically left - and - right, in the following description, without special distinction, the right - hand side will be described, and the description of the left - hand side will be omitted. Also, it should be noted that in Figures 1 to 5 , the upper side in the drawing may be set as the upper side (U - side) and the lower side in the drawing may be set as the lower side (U - side) for description.

[0081] The fuselage 7 includes a pair of support portions 70U, 70D arranged at intervals in the vertical direction and an intermediate support portion 70M arranged between the support portions 70U, 70D. In the present embodiment, the support portions 70U, 70D and the intermediate support portion 70M are respectively formed of plate - like members.

[0082] The drive units 3, 3 include a first drive source 30U, a second drive source 30D, a first driven portion 10U, and a second driven portion 10D. In addition, the drive units 3, 3 include a first biasing member 40U, a second biasing member 40D, a control portion 60, etc. In the present embodiment, the first drive source 30U and the second drive source 30D are composed of external - rotor motors in DC motors. In addition, the illustration and description of the power supply (battery) for driving the first drive source 30U and the second drive source 30D are omitted.

[0083] The first drive source 30U is supported via a base 31 on the outer side of the support portion 70U located on the upper side. In addition, the second drive source 30D is supported via a base 31 on the outer side of the support portion 70D located on the lower side. In the present embodiment, the second drive source 30D and the first drive source 30U are arranged symmetrically up - and - down with the intermediate support portion 70M interposed therebetween.

[0084] As Figure 5 shown, the drive shaft 32U of the first drive source 30U is rotatably supported by a support portion 70U via appropriate bearings (not shown). Further, the front end side of the drive shaft 32U is rotatably supported by an intermediate support portion 70M via appropriate bearings (not shown). Further, a first drive gear 15U as a pinion is externally fitted to an intermediate portion of the drive shaft 32U.

[0085] The drive shaft 32D of the second drive source 30D is rotatably supported by a support portion 70D via appropriate bearings (not shown). Further, the front end side of the drive shaft 32D is rotatably supported by an intermediate support portion 70M via appropriate bearings (not shown). Further, a second drive gear 15D as a pinion is externally fitted to an intermediate portion of the drive shaft 32D.

[0086] As Figures 1 to 5 shown, the first driven portion 10U is formed of a spur gear (straight gear) with a part cut off. The cut-off portion of the first driven portion 10U is formed to suppress interference with the blade 2 or the like. The first driven portion 10U is supported so as to be able to rotate in a direction around the axis of the first rotation shaft 11U with respect to the support portion 70U and the intermediate support portion 70M. Specifically, in the present embodiment, the first rotation shaft 11U is supported so as to be able to rotate with respect to the support portion 70U and the intermediate support portion 70M, and the first driven portion 10U is fixed to the first rotation shaft 11U by press-fitting or the like. Further, in the present embodiment, the first driven portion 10U is disposed closer to the intermediate support portion 70M side. The first driven portion 10U meshes with the first drive gear 15U and can receive the power output from the first drive source 30U and rotate in a direction around the axis of the first rotation shaft 11U (see Figure 5 ).

[0087] Further, a first blade shaft holding portion 50U for holding a first blade shaft 20 described later is supported by the first driven portion 10U. The first blade shaft holding portion 50U rotates integrally with the first driven portion 10U in a direction around the first rotation axis.

[0088] Further, a bearing 51 is supported by the first blade shaft holding portion 50U so as to face the radially outer side of the first driven portion 10U. In other words, the bearing 51 is supported by the first driven portion 10U in a direction intersecting the first rotation shaft 11U (in the present embodiment, an orthogonal direction, hereinafter also referred to as a direction around the third axis). The first blade shaft 20 described later is supported by the bearing 51 so as to be able to rotate in a direction around the third axis.

[0089] The second driven part 10D is formed by a spur gear (spur gear) with a part removed. The removed part of the second driven part 10D is formed to suppress interference with the blade 2 or the like. The second driven part 10D is supported so as to be rotatable relative to the support part 70D and the intermediate support part 70M in a direction around the axis of the second rotation shaft 11D. Specifically, in the present embodiment, the second rotation shaft 11D is supported so as to be rotatable relative to the support part 70D and the intermediate support part 70M, and the second driven part 10D is fixed to the second rotation shaft 11D by press-fitting or the like. In addition, in the present embodiment, the second driven part 10D is disposed closer to the intermediate support part 70M side. The second driven part 10D meshes with the second drive gear 15D and can receive the power output from the second drive source 30D and rotate in a direction around the axis of the second rotation shaft 11D (also referred to as the direction around the second rotation axis). That is, the second driven part 10D and the first driven part 10U are disposed substantially symmetrically above and below with the intermediate support part 70M interposed therebetween.

[0090] In addition, a second blade shaft holding part 50D for holding a second blade shaft 21 described later is supported by the second driven part 10D. The second blade shaft holding part 50D rotates integrally with the second driven part 10D in a direction around the second rotation axis.

[0091] As Figure 3 and Figure 4 shown, a bearing 52 (see Figure 4 ) is supported by the second blade shaft holding part 50D so as to face the outside of the second driven part 10D. In other words, the bearing 52 is supported in a direction crossing the second rotation shaft 11D (in the radial direction of the second rotation shaft 11D in the present embodiment, hereinafter also referred to as the direction around the fifth axis). A link member 53 is supported by the bearing 52 so as to be rotatable in a direction around the fifth axis.

[0092] The link member 53 is formed such that the other end side extends toward the second blade shaft 21 described later. A bearing 54 is supported on the other end side of the link member 53 in the direction of the fourth axis. The second blade shaft 21 described later is supported by the bearing 54 so as to be rotatable in a direction around the fourth axis.

[0093] As Figures 1 to 5As shown, the first biasing member 40U is formed of a torsion spring and is disposed between the support portion 70U and the first driven portion 10U. In addition, the first biasing member 40U is disposed around the axis of the first rotation shaft 11U. The first biasing member 40U applies a force in a direction opposite to the rotation direction of the first driven portion 10U as the first driven portion 10U rotates. Specifically, one end side (front end side) of the first biasing member 40U is connected to the support portion 70U, and the other end side (rear side) is connected to the first driven portion 10U. Therefore, the first biasing member 40U can apply a force in a direction opposite to the rotation direction of the first driven portion 10U as the first driven portion 10U rotates.

[0094] The second biasing member 40D is also formed of a torsion spring like the first biasing member 40U and is disposed between the support portion 70D and the second driven portion 10D. In addition, the second biasing member 40D is disposed around the axis of the second rotation shaft 11D. The second biasing member 40D applies a force in a direction opposite to the rotation direction of the second driven portion 10D as the second driven portion 10D rotates. Specifically, one end side (rear end side) of the second biasing member 40D is connected to the support portion 70D, and the other end side (front end side) is connected to the second driven portion 10D. Therefore, the second biasing member 40D can apply a force in a direction opposite to the rotation direction of the first driven portion 10U as the second driven portion 10D rotates.

[0095] The blade 2 has a first blade shaft 20, a second blade shaft 21, a blade body 22, and the like.

[0096] The first blade shaft 20 is formed to extend in a predetermined axial direction (the radial direction of the first rotation shaft 11U in the present embodiment). The first blade shaft 20 is connected to the first driven portion 10U at one end side and is connected so as to be rotatable in a direction around a third rotation axis intersecting the axis of the first rotation shaft 11U. Specifically, the first blade shaft 20 is rotatably supported by a bearing 51 of the first blade shaft holding portion 50U at one end side. In addition, the first blade shaft 20 is applied with a force in a direction opposite to the rotation direction by the first biasing member 40U as the first driven portion 10U rotates. Thereby, the first blade shaft 20 is excited in the rotation direction (direction around the first rotation axis) of the first driven portion 10U.

[0097] The second blade shaft 21 is formed to extend along a specified axial direction (in this embodiment, a direction inclined at a specified inclination angle with respect to the first blade shaft 20). The second blade shaft 21 is connected to the second driven part 10D on one end side and is connected in a manner capable of rotating in a direction around a fourth rotation axis intersecting the axis of the second rotation shaft 11D. Specifically, the second blade shaft 21 is rotatably supported by a bearing 54 of a link member 53 on one end side. In other words, the second blade shaft 21 is connected to the second driven part 10D via the link member 53 on the second blade shaft holding part 50D in a manner capable of rotating in a direction around the fourth rotation axis.

[0098] Accordingly, even when the second blade shaft 21 is inclined with respect to the first blade shaft 20 (for example, when the blade 2 is formed in a fan shape), the flapping device 1 can reliably support the second blade shaft 21 in a rotatable manner according to the inclination direction (the fourth rotation axis direction). Thereby, it is possible to expect an improvement in the design freedom and aerodynamic characteristics of the blade 2.

[0099] In addition, as the second blade shaft 21 rotates with the second driven part 10D, a force in a direction opposite to the rotation direction is applied to the second blade shaft 21 by the second biasing member 40D. Accordingly, the second blade shaft 21 is excited in the rotation direction (the direction around the second rotation axis) of the second driven part 10D.

[0100] The blade main body 22 is provided across the first blade shaft 20 and the second blade shaft 21. In this embodiment, the blade main body 22 is formed in a substantially fan shape. The blade main body 22 can reciprocally swing by the drive of the first drive source 30U and the second drive source 30D, thereby generating lift.

[0101] The control unit 60 controls the output of the driving forces of the first drive source 30U and the second drive source 30D. That is, a reciprocating motion is applied to the blade 2 by controlling the output of the driving forces of the first drive source 30U and the second drive source 30D.

[0102] Figure 6 It is an explanatory diagram showing the operation of the blade 2 when the control unit 60 controls to set a specified difference between the output phases of the first drive source 30U and the second drive source 30D. Figure 6An example in [the above] is an example where the output phase of the first drive source 30U is shifted so as to lead the output phase of the second drive source 30D by 3%. In this way, by setting a phase difference between the first drive source 30U and the second drive source 30D (the two are also collectively referred to as drive sources 30, 30), the blade 2 is inclined by a specified angle (e.g., 30 degrees) in a direction opposite to the traveling direction. Specifically, as shown in the figure, for example, when the blade 2 flaps toward the front side, the blade 2 is inclined by a specified angle toward the rear side. In addition, for example, when the blade 2 flaps toward the rear side, the blade 2 is inclined by a specified angle toward the front side. That is, by setting a phase difference in the amplitudes of the first blade shaft 20 and the second blade shaft 21, the blade 2 is inclined by a specified angle in a direction opposite to the traveling direction. Thereby, the flapping wing device 1 described above can efficiently generate lift. In addition, the inclination angle of the blade 2 can be appropriately changed according to the flight mode.

[0103] Here, the control unit 60 can, for example, increase or decrease the lift by controlling the output of the drive source 30 so that the amplitudes of the pair of blades 2, 2 increase or decrease by the same amount. In addition, the control unit 60 can, for example, generate a torque (driving force) in the roll direction by the difference in lift between the left and right by controlling the outputs of the drive sources 30, 30 by setting a difference in the amplitudes of the pair of blades 2, 2.

[0104] In addition, the control unit 60 can perform a first offset control for offsetting the amplitude center of the first biasing member 40U by a specified amount to one side or the other side around the first rotation axis, and a second offset control for offsetting the amplitude center of the second biasing member 40D by a specified amount to one side or the other side around the second rotation axis.

[0105] Figure 8 (a) in [the figure] is an explanatory diagram of the case where the amplitude center of the biasing member 40 is offset. In addition, it should be noted that, in Figure 8 (a) of [the figure], the angle at which the amplitude center of the biasing member 40 is offset is exaggeratedly depicted for easy understanding. The first offset control and the second offset control are to offset the amplitude center of either one or both of the first biasing member 40U and the second biasing member 40D in the front-rear direction (the solid line position on the front side in the present embodiment). That is, the first offset control and the second offset control offset the center of lift in the front-rear direction (the front side in the present embodiment).

[0106] Specifically, as in Figure 8As shown in (b) thereof, the first offset control and the second offset control can be executed by applying an offset of a specified amount T to the drive voltage waveform (also referred to as the output waveform) of either or both of the first drive source 30U and the second drive source 30D. Applying an offset to the drive voltage waveform can be executed, for example, by setting a difference between the output of the drive voltage in the forward direction and the output of the drive voltage in the backward direction. That is, the amplitude center of the force applying member 40 is offset (refer to Figure 8 (a) thereof). Thereby, the control unit 60 can generate a torque in the pitching direction. Here, the angle by which the amplitude center of the force applying member 40 is offset can be, for example, 5 to 10 degrees. Further, in the flapping wing device 1 of the first embodiment, when generating the above offset, it is necessary to overcome the force applying members 40, 40 and increase the output of the drive sources 30, 30. In addition, according to the flight mode of the flapping wing device 1, the offset amounts of the first drive source 30U and the second drive source 30D can be the same or different from each other.

[0107] In addition, the control unit 60 can generate a torque in the yaw direction, for example, by controlling the output of the drive sources 30, 30 in such a manner as to set a difference in the speed in the front-rear direction during the reciprocating motion, and by controlling the output of the drive sources 30, 30 in such a manner that the direction of the speed difference between the left and right blades 2, 2 is opposite.

[0108] Figure 7 is an explanatory diagram of the output characteristics in the drive source 30 and the output region used in the flapping wing device 1 of the present invention. As shown in the figure, when the drive source 30 uses an electric motor (an outer rotor motor in this embodiment), at the time of the return (switching between the forward motion and the reverse motion) during the reciprocating motion of the blade 2, the electro-mechanical conversion efficiency in the drive source 30 tends to decrease. In addition, in the above flapping wing device 1, the reciprocating motion is autonomously returned at the return end of the reciprocating motion of the blade 2 by the restoring forces of the first force applying member 40U and the second force applying member 40D.

[0109] Therefore, in the present embodiment, the control unit 60 performs the following control: before a specified time when the rotational speeds of the first drive source 30U and the second drive source 30D become zero during the forward or reverse rotation switching of the first drive source 30U and the second drive source 30D, the first drive source 30U and the second drive source 30D are stopped from outputting the driving force. Here, the specified time can be arbitrarily set according to the characteristics (for example, the output efficiency) of the first drive source 30U and the second drive source 30D used. In addition, the control unit 60 performs the following control together with the above control: at the moment when the reciprocating motion of the blade 2 is switched by the restoring forces of the first force applying member 40U and the second force applying member 40D, the first drive source 30U and the second drive source 30D are restarted to output the driving force.

[0110] Accordingly, it is possible to stop driving by the drive source 30 at a portion where the efficiency of the drive source 30 is reduced. Therefore, it is possible to reduce the waste of the output of the drive source 30, and it is possible to expect an improvement in the power consumption rate of the drive battery. In this way, the above-described flapping device 1 can efficiently reciprocate the blades 2. In addition, the above-described flapping device 1 performs the following control: the drive source 30 restarts driving at the moment when the reciprocating or returning movement of the pair of blades 2, 2 is switched by the restoring forces of the first biasing member 40U and the second biasing member 40D. Accordingly, the above-described flapping device 1 can perform excitation of the blade 2 in a region where the angular velocity of the blade 2 near the center of flapping is large. In addition, the above-described flapping device 1 can efficiently perform flapping motion without increasing the capacity of the drive source 30. Therefore, it is possible to expect miniaturization of the above-described flapping device 1.

[0111] The above is the configuration of the flapping device 1 according to the first embodiment of the present invention. In addition, in the above, the configurations of the symmetrically arranged portions are the same, so the description thereof is omitted. Next, the operation and effect of the flapping device 1 according to an embodiment of the present invention will be described below.

[0112] The first blade shaft 20 of the above-described flapping device 1 is driven by the first drive source 30U, and the second blade shaft 21 is driven by the second drive source 30D. That is, the blade 2 is driven by both the first drive source 30U and the second drive source 30D. The stroke angle of the blade 2 is defined by the rotation angle of the first drive source 30U, and the angle of attack of the blade 2 is defined by the difference in the rotation angles of the first drive source 30U and the second drive source 30D. Accordingly, the above-described flapping device 1 can independently control the stroke and the angle of attack, and can achieve a more maneuverable flight such as moving horizontally while maintaining the posture.

[0113] In addition, the above-described flapping device 1 can vibrate the first blade shaft 20 and the second blade shaft 21 in the direction around the first rotation axis and the direction around the second rotation axis by the biasing force of the first biasing member 40U and the second biasing member 40D (both are also referred to as the biasing member 40). Therefore, the above-described flapping device 1 can increase the flapping frequency of the pair of blades 2, 2 by vibration, and thus can drive the pair of blades 2, 2 at high speed.

[0114] In addition, in the present embodiment, the first drive source 30U and the second drive source 30D in the above-described flapping device 1 are composed of an outer rotor motor in a DC motor. Therefore, the above-described flapping device 1 can increase the inertia generated by the rotor constituting the motor. Accordingly, the above-described flapping device 1 can reduce the change in the resonance frequency of the resonance system and the change in the blade amplitude, and thus the control is stable. Therefore, the above-described flapping device 1 can reduce the influence of external disturbances (such as air flow) received by the flapping device 1, and it is possible to expect further stabilization of the control.

[0115] In addition, the above flapping-wing device 1 can reduce the costs of the first drive source 30U and the second drive source 30D by using an outer-rotor motor that is less expensive than an inner-rotor motor. Therefore, the above flapping-wing device 1 can expect to further reduce costs by replacing the four drive sources, namely the pair of left and right first drive sources 30U, 30U and the pair of left and right second drive sources 30D, 30D, with outer-rotor motors.

[0116] In addition, the above flapping-wing device 1 has a fuselage 7 that supports a pair of drive units 3, 3, and the fuselage 7 has a pair of support portions 70U, 70D that are arranged at intervals. In addition, the first drive source 30U and the second drive source 30D are arranged outside the pair of support portions 70U, 70D, and the first biasing member 40U, the second biasing member 40D, the first driven portion 10U, and the second driven portion 10D are arranged between the pair of support portions 70U, 70D.

[0117] Thereby, the drive source 30 of the above flapping-wing device 1 does not interfere with the first biasing member 40U, the second biasing member 40D, the first driven portion 10U, and the second driven portion 10D. Therefore, in the case where the outer-rotor motor is used as the drive source 30 in the above flapping-wing device 1, for example, interference between the rotor of the outer-rotor motor and the first biasing member 40U, the second biasing member 40D, the first driven portion 10U, and the second driven portion 10D can be suppressed. In this way, even when the rotor is exposed like an outer-rotor motor, the above flapping-wing device 1 can suppress the enlargement of the device.

[0118] The above is the configuration and effects of the flapping-wing device 1 according to the first embodiment of the present invention. Next, the flapping-wing device 100 according to the second embodiment of the present invention will be described in detail. In addition, compared with the above flapping-wing device 1, the flapping-wing device 100 according to the second embodiment has the same configuration except for the connection method of the first biasing member 40U and the second biasing member 40D and the partial arrangement of each component, so the description of the same parts will be omitted. In addition, it should be noted that the same reference numerals are used for the components that are the same as those of the above flapping-wing device 1. In addition, since the flapping-wing device 100 is configured symmetrically about the left and right, one side will be described and the description of the other side will be omitted.

[0119] However, in the flapping-wing device 1 according to the above-described first embodiment, one end sides of the biasing members 40, 40 are connected to the support portions 70U, 70D, and the other sides are connected to the first driven portion 10U or the second driven portion 10D. Here, when increasing the flapping frequency of the flapping-wing device 1 in order to reduce the influence of external disturbances, for example, it is possible to consider increasing the spring constant of the torsion springs or the like used for the biasing members 40, 40. However, when the spring constant of the biasing members 40, 40 is increased, the restoring force also becomes stronger, so the load becomes larger, and there is a concern that it may be difficult to flap the first blade shaft 20 and the second blade shaft 21. As a result, there is a concern that the lift force may decrease. Therefore, an object of the second embodiment is to provide a flapping-wing device 100 that can further increase the lift force and stabilize the control by suppressing the concerns in the first embodiment.

[0120] <<Second Embodiment>>

[0121] As Figure 9 shown, the flapping-wing device 100 according to the second embodiment includes a pair of blades 2, 2 and a pair of drive portions 3, 3 provided corresponding to the pair of blades 2, 2, respectively. In addition, the drive portion 3 includes a first drive source 30U, a second drive source 30D, a first driven portion 10U, and a second driven portion 10D. In addition, in addition to the above-described configuration, the drive portion 3 further includes a first biasing member 40U, a second biasing member 40D, and a control portion 60 that controls the output of the driving force of the first drive source 30U and the second drive source 30D, and the like.

[0122] One end side of the first biasing member 40U in the flapping-wing device 100 is connected to the first driven portion 10U, and the other end side is directly or indirectly connected to the first blade shaft 20. Specifically, one end side of the first biasing member 40U is connected to the first driven portion 10U, and the other end side is connected to the first blade shaft holding portion 50U.

[0123] In addition, one end side of the second biasing member 40D is connected to the second driven portion 10D, and the other end side is directly or indirectly connected to the second blade shaft 21. Specifically, one end side of the second biasing member 40D is connected to the second driven portion 10D, and the other end side is connected to the second blade shaft holding portion 50D. That is, one end sides of the first biasing member 40U and the second biasing member 40D (also collectively referred to as the biasing members 40, 40) are not fixed to the fuselage 7 constituting the flapping-wing device 100, but are fixed to the first driven portion 10U and the second driven portion 10D. In other words, one end sides of the biasing members 40, 40 become free ends. In addition, in the second embodiment, the first driven portion 10U is supported so as to be rotatable relative to the first rotation shaft 11U, and the second driven portion 10D is supported so as to be rotatable relative to the second rotation shaft 11D.

[0124] The above is the configuration of the flapping wing device 100 according to the second embodiment of the present invention. However, the flapping wing device 100 can shift the amplitude centers of the biasing members 40, 40 in the same manner as in the first embodiment. That is, the flapping wing device 100 according to the second embodiment can perform the above-described first shift control and second shift control.

[0125] As Figure 10 shown, the first shift control and the second shift control can be performed by applying an offset of a predetermined amount T to the drive voltage waveform (output waveform) of either one or both of the first drive source 30U and the second drive source 30D. In addition, depending on the flight mode of the flapping wing device 100, the offset amounts of the first drive source 30U and the second drive source 30D may be the same or different from each other.

[0126] In this way, the above flapping wing device 100 can easily perform the first shift control and the second shift control by applying an offset of a predetermined amount T to the drive voltage waveforms of the first drive source 30U and the second drive source 30D. Therefore, according to the above flapping wing device 100, both high-precision control and stable control can be expected. In addition, since one end sides of the biasing members 40, 40 of the flapping wing device 100 according to the second embodiment are free ends, as Figure 10 shown, it is possible to easily apply an offset to the drive voltage waveforms of the drive sources 30, 30. That is, it is possible to easily apply an offset to the drive voltage waveform (can be relatively offset) without depending on the restoring force of the biasing members 40, 40.

[0127] The above is the configuration of the flapping wing device 100 according to the second embodiment of the present invention. Next, the operation and effect of the flapping wing device 100 will be described in detail.

[0128] As described above, even when a torque (acting force) is applied to the biasing members 40, 40, the flapping wing device 100 can vibrate the first blade shaft 20 and the second blade shaft 21 without being affected by the restoring force of the biasing members 40, 40. That is, the above flapping wing device 100 can directly apply a torque to the first blade shaft 20 and the second blade shaft 21. Thereby, it is possible to expect stable output control of the drive sources 30, 30. In addition, the biasing members 40, 40 are preferably members that can apply a torque in the torsional direction, such as a torsion spring.

[0129] In addition, one end side of the force applying members 40, 40 of the flapping device 100 is a free end. Therefore, even if the spring constants of the force applying members 40, 40 are increased, it is not easily affected by the restoring forces of the force applying members 40, 40. Therefore, according to the flapping device 100 described above, the spring constants of the force applying members 40, 40 can be increased, thereby increasing the flapping frequency. Therefore, it is possible to expect the output control of the drive sources 30, 30 to become stable. In addition, as the spring constants of the force applying members 40, 40 increase, the weights of the force applying members 40, 40 can be increased. Therefore, it is possible to expect the influence of external disturbances to be further reduced.

[0130] In addition, the first blade shaft 20 of the flapping device 100 is driven by the first drive source 30U, and the second blade shaft 21 is driven by the second drive source 30D. The stroke angle of the blade 2 is defined by the rotation angle of the first drive source 30U, and the angle of attack of the blade 2 is defined by the difference in the rotation angles of the first drive source 30U and the second drive source 30D. Thus, the flapping device 100 can independently control the stroke and the angle of attack, and can achieve more maneuverable flight such as moving horizontally while maintaining the posture.

[0131] In addition, the flapping device 100 can independently control the driving of the first drive source 30U and the second drive source 30D respectively, and thus can fly in all directions. Here, the first drive source 30U and the second drive source 30D (also collectively referred to as the drive sources 30, 30) can use various motors and the like, but it is preferable to use a brushless DC motor that is easy to reverse and has a high power-to-weight ratio. Thereby, battery driving becomes easier and control can also be easily performed.

[0132] Here, in the above first offset control and second offset control, one end side of the force applying members 40, 40 is a free end. Therefore, there is a concern that the amplitude center of the force applying members 40, 40 after offset deviates from the predetermined amplitude center (also referred to as the reference position) as the force applying members 40, 40 vibrate. Therefore, as Figure 11 shown, the flapping device 200 according to the third embodiment is further provided with a third force applying member 41U and a fourth force applying member 41D to return the amplitude center of the offset force applying members 40, 40 to the reference position. Hereinafter, the flapping device 200 according to the third embodiment will be described in detail. In addition, since the flapping device 200 according to the third embodiment is provided with the third force applying member 41U and the fourth force applying member 41D with respect to the flapping device 100 according to the second embodiment, the description of the same parts as those of the flapping device 100 according to the second embodiment will be omitted. In addition, the flapping device 200 according to the third embodiment is configured symmetrically about the left and right, so one side will be described and the description of the other side will be omitted.

[0133] 《Third Embodiment》

[0134] As Figure 11 shown, in addition to the configuration of the flapping wing device 100 (refer to Figure 9 ) related to the second embodiment, the flapping wing device 200 related to the third embodiment further includes a third biasing member 41U and a fourth biasing member 41D.

[0135] The third biasing member 41U uses, for example, a torsion spring. As the first driven portion 10U rotates, the third biasing member 41U applies a force to the first driven portion 10U in a direction opposite to the rotation direction of the first driven portion 10U. Specifically, the third biasing member 41U is connected to the fuselage 7 (the intermediate support portion 70M in this embodiment) at one end side and is connected to the first driven portion 10U at the other end side.

[0136] In addition, the third biasing member 41U can exert a force smaller than that of the first biasing member 40U and can exert a force that can return the amplitude center of the first biasing member 40U to the reference position. For example, the third biasing member 41U uses a torsion spring having a spring constant smaller than that of the first biasing member 40U. Therefore, the influence of the third biasing member 41U on the first biasing member 40U is limited.

[0137] Here, the spring constant of the third biasing member 41U can utilize various coefficients that can exert a force capable of returning the amplitude center of the first biasing member 40U to the reference position. In addition, the spring constant of the third biasing member 41U is preferably determined in consideration of the balance between the influence on the first biasing member 40U and the force for returning the amplitude center to the reference position.

[0138] The fourth biasing member 41D uses, for example, a torsion spring. As the second driven portion 10D rotates, the fourth biasing member 41D applies a force to the second driven portion 10D in a direction opposite to the rotation direction of the second driven portion 10D. Specifically, the fourth biasing member 41D is connected to the fuselage 7 (the intermediate support portion 70M in this embodiment) at one end side and is connected to the second driven portion 10D at the other end side.

[0139] In addition, the fourth biasing member 41D can exert a force smaller than that of the second biasing member 40D and can exert a force that can return the amplitude center of the second biasing member 40D to the reference position. For example, the fourth biasing member 41D uses a torsion spring having a spring constant smaller than that of the second biasing member 40D. Therefore, the influence of the fourth biasing member 41D on the second biasing member 40D is limited.

[0140] Here, the spring constant of the fourth biasing member 41D can utilize various coefficients that can exert a force capable of returning the amplitude center of the second biasing member 40D to the reference position. Additionally, the spring constant of the fourth biasing member 41D is preferably determined in consideration of the balance between the influence on the second biasing member 40D and the force for returning the amplitude center to the reference position.

[0141] Thus, even when one end sides of the first biasing member 40U and the second biasing member 40D become free ends, the flapping device 200 according to the third embodiment can return the amplitude centers of the first biasing member 40U and the second biasing member 40D to the reference position (predetermined amplitude center). Therefore, according to the above flapping device 200, it is possible to expect further improvement in control accuracy and stability.

[0142] The above are the configurations and effects of the flapping devices 1, 100, and 200 according to the first to third embodiments of the present invention. However, the flapping devices 1, 100, and 200 of the present invention are not limited to the above embodiments and can be variously modified.

[0143] For example, the pair of blades 2, 2 can be formed into various shapes and sizes. Additionally, in the present embodiment, a pair of blades 2, 2 are provided, but the number of blades 2 provided can be appropriately changed to two pairs or the like, for example. Also, the first blade shaft 20, the second blade shaft 21, and the blade main body 22 can be formed into various shapes and sizes, and the forming directions can also be appropriately changed.

[0144] Furthermore, in the present embodiment, an example is shown where the drive sources 30, 30 utilize an outer rotor motor in a DC motor, but the drive sources 30, 30 can utilize various motors or the like that can exert a driving force. For example, the drive sources 30, 30 can also be constituted by an inner rotor motor in a DC motor. Additionally, in the present embodiment, the first drive source 30U and the second drive source 30D are constituted by the same outer rotor motor, but different types of drive sources can also be used separately.

[0145] Moreover, in the present embodiment, the first driven portions 10U and the second driven portions 10D use spur gears (straight gears) and are driven by the first drive gears 15U and the second drive gears 15D serving as pinions, but the present invention is not limited thereto. The first driven portions 10U and the second driven portions 10D can utilize various types of driven portions. For example, the first driven portions 10U and the second driven portions 10D can also be formed by pulleys or the like and be driven by a transmission belt or the like. Additionally, depending on the types of the first driven portions 10U and the second driven portions 10D, the first drive gears 15U and the second drive gears 15D can utilize not only gears but also various methods.

[0146] In addition, in the present embodiment, torsion springs are used as the first biasing member 40U, the second biasing member 40D, the third biasing member 41U, and the fourth biasing member 41D, but the present invention is not limited thereto. The first biasing member 40U, the second biasing member 40D, the third biasing member 41U, and the fourth biasing member 41D are not limited to torsion springs, and various components can be used. In addition, in the present embodiment, the same type of torsion springs are used as the first biasing member 40U, the second biasing member 40D, the third biasing member 41U, and the fourth biasing member 41D, but different types of biasing members can also be used respectively. In addition, the arrangements of the first biasing member 40U, the second biasing member 40D, the third biasing member 41U, and the fourth biasing member 41D can be variously changed within the scope of the present invention. In addition, in the present embodiment, the control is uniformly performed by a single control unit 60, but the control unit 60 can also be composed of multiple units and be controlled by function differentiation, etc.

[0147] In addition, in the present embodiment, the second blade shaft 21 is connected to the link member 53 so as to be rotatable in a direction around the fourth rotation axis, but the second blade shaft 21 can be connected not only via the link member 53 but also directly or indirectly to the second driven part 10D. In addition, the link member 53 can be formed into various shapes and sizes according to the forming direction of the second blade shaft 21. In addition, multiple link members 53 can also be provided as needed. In addition, the fourth rotation axis direction and the fifth axis direction can be formed into various directions according to the forming direction of the second blade shaft 21.

[0148] In addition, in the present embodiment, control is performed to stop the first drive source 30U and the second drive source 30D from outputting driving force before a specified time when the rotational speeds of the first drive source 30U and the second drive source 30D become zero, but the timing of stopping the output can be appropriately changed according to the characteristics of the motor or the like used. In addition, in the present embodiment, the following control is performed: when the reciprocating or reciprocating motion of the blade 2 is switched by the restoring forces of the first biasing member 40U and the second biasing member 40D, the first drive source 30U and the second drive source 30D are restarted to output driving force, but the timing of restarting the output of the driving force can also be appropriately changed according to the characteristics of the motor or the like used.

[0149] In addition, regarding the offset amounts in the first offset control and the second offset control performed by the control unit 60, various offset amounts can be set according to the flight modes of the flapping wing devices 1, 100, and 200. In addition, the offset amounts in the first offset control and the second offset control can be the same respectively, or can be different according to the flight modes.

[0150] In addition, in the present embodiment, the control unit 60 performs the following control: the output phases of the first drive source 30U and the second drive source 30D are set to have a difference so that the blade 2 is inclined by a predetermined angle in a direction opposite to the traveling direction, but the angle by which the blade 2 is inclined can be set to various angles according to the flight mode, flight environment, etc. In addition, the control of the blade 2 is not limited to the above embodiment, and various controls can be performed according to the flight mode and the like.

[0151] The above are various embodiments and modification examples of the flapping wing device according to the present invention. However, the present invention is not limited to the contents illustrated in the above embodiments and modification examples, and other embodiments can be obtained within the scope of the protection without departing from the scope, which is easily understood by those skilled in the art according to its teachings and spirit.

[0152] (Industrial Applicability)

[0153] The flapping wing device of the present invention can be used for various surveys, repairs, photography, etc. in the air.

Claims

1. A flapping wing device, characterized in that, it has: a pair of blades; and a pair of drive units respectively provided corresponding to the pair of blades, wherein the drive unit includes: a first drive source; a second drive source; a first driven part that rotates around a first rotation axis by receiving power output from the first drive source; a second driven part that rotates around a second rotation axis by receiving power output from the second drive source; a first biasing member that applies a force in a direction opposite to the rotation direction of the first driven part as the first driven part rotates; a second biasing member that applies a force in a direction opposite to the rotation direction of the second driven part as the second driven part rotates; and a control unit that controls the output of the driving forces of the first drive source and the second drive source, wherein the blade has: a first blade shaft extending along a specified axis direction, connected to the first driven part at one end side and connected in a manner capable of rotating around a third rotation axis that intersects the first rotation axis; a second blade shaft extending in a direction intersecting the first blade shaft, connected to the second driven part at one end side and connected in a manner capable of rotating around a fourth rotation axis that intersects the second rotation axis; and a blade body provided across the first blade shaft and the second blade shaft.

2. A flapping wing device, characterized in that, it has: a pair of blades; and a pair of drive units respectively provided corresponding to the pair of blades, wherein the drive unit includes: a first drive source; a second drive source; a first driven part that rotates around a first rotation axis by receiving power output from the first drive source; a second driven part that rotates around a second rotation axis by receiving power output from the second drive source; a first biasing member that applies a force in a direction opposite to the rotation direction of the first driven part as the first driven part rotates; a second biasing member that applies a force in a direction opposite to the rotation direction of the second driven part as the second driven part rotates; and a control unit that controls the output of the driving forces of the first drive source and the second drive source, wherein the blade has: a first blade shaft extending along a specified axis direction, connected to the first driven part at one end side and connected in a manner capable of rotating around a third rotation axis that intersects the first rotation axis; a second blade shaft extending in a direction intersecting the first blade shaft, connected to the second driven part at one end side and connected in a manner capable of rotating around a fourth rotation axis that intersects the second rotation axis; and a blade body provided across the first blade shaft and the second blade shaft, wherein the first biasing member is connected to the first driven part at one end side and directly or indirectly connected to the first blade shaft at the other end side, The second biasing member is connected to the second follower portion on one end side, and is directly or indirectly connected to the second blade shaft on the other end side.

3. The flapping device according to claim 1 or 2, wherein, the flapping device has a link member, the link member is connected to the second follower portion on one end side in a manner capable of rotating about a fifth axis, the fifth axis intersects the second rotation axis, the link member is formed such that the other end side extends toward the second blade shaft, and is connected to the second blade shaft in a manner capable of rotating about the fourth rotation axis.

4. The flapping device according to claim 1 or 2, wherein, the first drive source and the second drive source are constituted by an outer rotor electric machine in a DC motor.

5. The flapping device according to claim 1 or 2, wherein, the control unit performs the following control: before a specified time when the rotational speeds of the first drive source and the second drive source become zero during the forward or reverse rotation switching of the first drive source and the second drive source, the first drive source and the second drive source are stopped from outputting driving force, and performs the following control: at the moment when the forward or reverse movement of the blade is switched by the restoring forces of the first biasing member and the second biasing member, the first drive source and the second drive source are restarted to output driving force.

6. The flapping device according to claim 1 or 2, wherein, the control unit is capable of executing a first offset control and a second offset control, the first offset control offsets the amplitude center of the first biasing member by a specified amount to one side or the other side about the first rotation axis, the second offset control offsets the amplitude center of the second biasing member by a specified amount to one side or the other side about the second rotation axis, the first offset control and the second offset control are executed by applying a specified amount of offset to the drive voltage waveforms of the first drive source and the second drive source.

7. The flapping device according to claim 2, wherein, the flapping device has a fuselage that supports the pair of drive portions, the flapping device has: a third biasing member that applies a force in a direction opposite to the rotation direction of the first follower portion to the first follower portion as the first follower portion rotates; and a fourth biasing member that applies a force in a direction opposite to the rotation direction of the second follower portion to the second follower portion as the second follower portion rotates, the third biasing member is connected to the fuselage on one end side, and is directly or indirectly connected to the first blade shaft on the other end side, the fourth biasing member is connected to the fuselage on one end side, and is directly or indirectly connected to the second blade shaft on the other end side, the third biasing member and the fourth biasing member are formed to be able to exert a force smaller than the forces of the first biasing member and the second biasing member, and are able to exert a force capable of returning the amplitude centers of the first biasing member and the second biasing member to the reference position.

8. The flapping wing device according to claim 1 or 2, characterized in that, the control unit performs the following control: setting a phase difference between the outputs of the first drive source and the second drive source in such a manner that the blades are inclined by a predetermined angle in a direction opposite to the traveling direction.

9. The flapping wing device according to claim 1 or 2, characterized in that, the flapping wing device has a fuselage that supports the pair of drive units, the fuselage has a pair of support portions arranged at intervals, the first drive source and the second drive source are arranged outside the pair of support portions, the first biasing member, the second biasing member, the first driven portion, and the second driven portion are arranged between the pair of support portions.

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