Flapping wing device

Abstract

The invention provides a flapping-wing flying robot which is small and can fly with high maneuverability. A flapping wing device (1) is provided with blades (2, 2) and a drive unit (3). The drive unit (3) is provided with a drive source (30), a driven unit (10) that rotates about a first rotational axis by the drive source (30), a first biasing member (40) that applies a biasing force to the driven unit (10) in the direction opposite the rotational direction of the driven unit (10), and a control unit (60). The blade (2) is provided with: a first blade shaft (20) which extends in a predetermined axial direction, is connected to the driven part (10) on one end side, and is connected so as to be able to rotate in a direction about a second rotational axis intersecting the first rotational axis; a second blade shaft (21) which extends in a direction intersecting the first blade shaft (20), is directly or indirectly connected to the driven part (10) on one end side, and is connected so as to be rotatable in a direction about the first rotational axis; and a blade body (22) provided across the first blade shaft (20) and the second blade shaft (21).

Description

Technical Field

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

[0002] Conventionally, flapping wing devices have been used for surveillance, photography, 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 flapping wings (equivalent to blades) by a DC motor (for example, Patent Document 1).

[0003] However, in recent years, with the diversification of uses, flapping wing devices have also been used for toys, etc. In addition, in investigations, repairs, or photography, etc. in narrow spaces, a flapping wing device that is small and capable of flying in a variety of flight modes is required. Here, since the lift applied to the blades depends on the blade length × flapping frequency, in order to obtain sufficient lift, it is essential to increase the flapping frequency of a small flapping wing flying robot. However, in the structure of Patent Document 1 above, the flapping frequency approaches the natural frequency (2*π*√(K / I)) (where K is the spring constant of the torsion spring and I is the rotational inertia of the entire system). Therefore, in Patent Document 1, emphasis is placed on minimizing I as much as possible, and an inner rotor type brushless DC motor or a brushed DC motor is used. On the other hand, these motors have the disadvantages of a low power-to-weight ratio, and the former is expensive and the latter has a short lifespan. Therefore, since I becomes large, it is necessary to combine it with a large K, that is, a heavier torsion spring, but in order to reduce costs, it is necessary to implement a structure that uses an outer rotor type brushless DC motor with a lower price and a higher power-to-weight ratio. In addition, a large I also has the following advantage: since the influence of aerodynamic load fluctuations on the flapping wing motion becomes relatively small, the flapping wing motion is stable, and thus attitude control can be stably performed. Therefore, research is being conducted on using an outer rotor type brushless DC motor in a small flapping wing robot.

[0004] Prior Art Documents

[0005] Patent Documents

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

[0007] However, when using an external rotor type motor without reducing the flapping frequency, since K increases with the large inertia of the motor, the torsion spring also becomes large-sized and the mass increases. Therefore, when using an external rotor type motor, since it is necessary to resist the restoring force of the large torsion spring, it is necessary to increase the offset voltage. Therefore, it may be necessary to use a larger motor power when applying the offset. In this way, although an external rotor type motor can be configured at low cost and the power-to-weight ratio can be improved, it may be necessary to use motor power when applying the offset. Therefore, there is a need for a flapping wing device that is inexpensive, can improve the power-to-weight ratio, and has a small structure.

[0008] Therefore, an object of the present invention is to provide a flapping wing device that can be configured at low cost, can improve the power-to-weight ratio, and has a small structure. In addition, an object of the present invention is to provide a flapping wing device that can also be used for toys and the like and can be realized at low cost.

[0009] (1) The flapping wing device of the present invention provided to solve the above problems is characterized by having: a pair of blades; and a drive unit provided corresponding to each of the pair of blades, the drive unit including: a drive source; a driven unit that rotates around a first rotation axis by receiving power output from the drive source; a first biasing member that applies a force in a direction opposite to the rotation direction of the driven unit as the driven unit rotates; and a control unit that controls the output of the driving force of the drive source, the blade having: a first blade shaft that extends in a predetermined axis direction, and is connected to the driven unit at one end side and is connected so as to be able to rotate in a direction around a second rotation axis, the second rotation axis intersecting the first rotation axis; a second blade shaft that extends in a direction intersecting the first blade shaft, and is directly or indirectly connected to the driven unit at one end side and is connected so as to be able to rotate in a direction around the first rotation axis; and a blade body that is provided across the first blade shaft and the second blade shaft.

[0010] The above flapping wing device can vibrate the first blade shaft in a direction around the first rotation axis by the biasing force of the first 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. Therefore, a strong lift force can be obtained. In addition, the first biasing member can preferably use a member such as a torsion spring that can apply a torque in the torsion direction.

[0011] In addition, the above flapping wing device can independently control the driving of the pair of drive sources, and thus can fly in all directions. Here, various motors and the like can be used as the drive source, but a brushless DC motor that is easy to reverse and has a high power-to-weight ratio can be preferably used. As a result, battery driving becomes easier and control can also be easily performed.

[0012] Here, when increasing the flapping frequency, for example, it is possible to consider increasing the spring constant of a torsion spring or the like used for the first biasing member. However, when the spring constant of the first biasing member (e.g., a torsion spring) is increased, the restoring force also becomes stronger. Therefore, there is a problem that a larger motor power is required to shift the center of the flapping amplitude.

[0013] That is, in order to apply a posture control torque in the pitching (nose up / down) direction to the flapping wing device, it is necessary to shift the center of the amplitude of the first biasing member to one side or the other side in the direction around the first rotation axis (hereinafter also referred to as the front-rear direction). However, when shifting the center of the amplitude of the first biasing member in the direction around the first rotation axis, that is, in the front-rear direction, there is a problem that the shift becomes difficult due to the restoring force of the first biasing member. In addition, when the spring constant of the first biasing member is increased, the restoring force becomes even stronger. Therefore, 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 reduce the power during control of the drive unit.

[0014] (2) Therefore, the flapping wing device of the present invention provided to solve the above problems is characterized by including: a pair of blades; and a drive unit provided corresponding to each of the pair of blades, the drive unit including: a drive source; a driven unit that rotates around a first rotation axis by receiving power output from the drive source; a first biasing member that applies a force in a direction opposite to the rotation direction of the driven unit as the driven unit rotates; and a control unit that controls the output of the driving force of the drive source, the blade having: a first blade shaft that extends along a specified axis direction, and is connected to the driven unit at one end side and is connected in a manner capable of rotating around a second rotation axis, the second rotation axis intersecting the first rotation axis; a second blade shaft that extends in a direction intersecting the first blade shaft, and is directly or indirectly connected to the driven unit at one end side and is connected in a manner capable of rotating around the first rotation axis; and a blade body that is provided across the first blade shaft and the second blade shaft, the first biasing member being connected to the driven unit at one end side and directly or indirectly connected to the first blade shaft at the other end side.

[0015] In the above flapping wing device, one end side of the first biasing member is connected to the driven unit, and the other end side is directly or indirectly connected to the first blade shaft. That is, one end side of the first biasing member is not fixed to the fuselage constituting the flapping wing device, but is fixed to the driven unit. In other words, one end side of the first biasing member becomes a free end.

[0016] In the above flapping wing device, one end side of the first biasing member becomes a free end. Therefore, it is possible to apply an offset to the flapping amplitude center without resisting the restoring force of the first biasing member. Thus, according to the above flapping wing device, even if the spring constant of the first biasing member is increased, it is possible to apply an offset to the flapping amplitude center without being affected by it. Therefore, it is possible to simultaneously increase the flapping frequency and suppress the required power during control.

[0017] In addition, in the above flapping wing device, since the second blade shaft can rotate about the first rotation axis, the stroke angle of the blade that is driven by the driving source and is affected by the wind is passively defined as the angle of attack of the blade. Thus, the above flapping wing device can flexibly capture the wind through the blade body, and thus can efficiently obtain lift. The driving 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. Thus, battery driving becomes easier and control can also be easily performed.

[0018] Here, in the case of using an inner rotor motor as the driving source, since the inertia generated by the rotor of the motor is small, the influence of the change in the inertia of the blade applied to the blade shaft due to the change in the posture (angle of attack) of the blade becomes relatively large. Along with this, the resonance frequency also changes significantly, and furthermore, the resonance coefficient (amplification rate of the blade amplitude) also changes significantly. Therefore, the control of the blade needs to consider the change in the blade amplitude, and there is a problem that the control becomes complicated. Thus, the inventors et al. further studied in depth and obtained the following insight: Compared with an inner rotor motor, in the case of using an outer rotor motor with a large inertia generated by the rotor, the change amount of the inertia of the first blade shaft due to the change in the posture of the blade is relatively small compared to the large inertia of the rotor of the outer rotor motor. Therefore, the change in the resonance frequency of the resonance system and the change in the blade amplitude also become smaller, and the control becomes easier.

[0019] (3) Therefore, the flapping wing device of the present invention is characterized in that the driving source is composed of an outer rotor motor in a DC motor.

[0020] By using an outer rotor motor that is cheaper than an inner rotor motor, the above flapping wing device can reduce the cost of the driving source. Thus, by replacing the two driving sources of a pair of driving sources with an outer rotor motor, the above flapping wing device can be expected to further reduce the cost. In addition, by using an outer rotor motor, the above flapping wing device can reduce the change in the resonance frequency of the resonance system and the change in the blade amplitude, and thus can be expected to further stabilize the control.

[0021] Here, after in-depth research, the inventors and the like obtained the following insights: In the above flapping wing device, when the reciprocating motion of the blade makes a U-turn (switching between the forward motion and the backward motion), the electrical and mechanical conversion efficiency of the drive unit (such as a motor) tends to decrease. In addition, in the above flapping wing device, due to the restoring force of the first biasing member, the reciprocating motion of the blade makes a U-turn autonomously at the U-turn end of the reciprocating motion of the blade. Therefore, it is considered that if the motor is stopped only at the U-turn end of the reciprocating motion of the blade and excitation is performed only in the region where the angular velocity of the blade near the center of flapping is large, the efficiency of the motor will be improved.

[0022] (4) Therefore, the above flapping wing device is characterized in that: the control unit performs the following control: before a predetermined time when the rotational speed of the drive source becomes zero during the forward or reverse rotation switching of the drive source, the drive source is stopped from outputting the driving force, and the following control is performed: after a predetermined time when the forward or reverse motion of the blade is switched by the restoring force of the first biasing member, the drive source is restarted to output the driving force.

[0023] The above flapping wing device performs the following control: before a predetermined time when the rotational speed of the drive source becomes zero during the forward or reverse rotation switching of the drive source, the drive source is stopped from driving. Thereby, it is possible to stop driving by the drive source at the part where the efficiency of the drive source decreases, and therefore, it is possible to reduce the waste of the output of the drive source, and it is possible to expect to improve the power consumption rate of the drive battery. In this way, the above flapping wing device can efficiently reciprocate the blade. In addition, the above flapping wing device performs the following control: after a predetermined time when the forward or reverse motion of a pair of blades is switched by the restoring force of the first biasing member, the drive source is restarted to drive. Thereby, the above flapping wing device can perform excitation of the blade in the region where the angular velocity of the blade near the center of flapping is large. In addition, the above flapping wing device can efficiently perform the flapping wing motion without increasing the capacity of the drive source. Therefore, it is possible to expect miniaturization of the above flapping wing device.

[0024] (5) The above flapping wing device of the present invention is characterized in that: the control unit can execute an offset control, the offset control offsets the amplitude center of the first biasing member by a predetermined amount to one side or the other side around the first rotation axis, and the offset control is executed by applying a predetermined amount of offset to the drive voltage waveform of the drive source.

[0025] The above flapping wing device can easily execute the offset control by applying a predetermined amount of offset to the drive voltage waveform of the drive source. Therefore, according to the above flapping wing device, both high-precision control can be performed and the control can be expected to be stabilized.

[0026] Here, in the above flapping wing device, when the blade flaps, it is preferable that the blade is inclined so that the vertical component of the normal vector toward the traveling direction of the blade faces downward in order to efficiently generate lift.

[0027] (6) Accordingly, the flapping device of the present invention described above is characterized in that it has a rotation limiter, and the rotation limiter is used to maintain the inclination of the blade at a specified angle due to the resistance brought by the wind pressure, so that the vertical component of the normal vector of the blade surface facing the traveling direction is downward, and the wind pressure is generated by the relative velocity difference between the movement of the blade and the surrounding fluid.

[0028] By adopting this configuration, the above flapping device can efficiently generate lift.

[0029] Here, in the above-mentioned offset control, when one end side of the first biasing member is a free end, there is a concern that the amplitude center of the biasing member after offset deviates from the predetermined amplitude center (also referred to as the reference position) as the biasing member vibrates. That is, when one end side of the first biasing member is a free end, since the amplitude center is not fixed to the housing, there is a problem that it cannot be mechanically determined. Therefore, it is necessary to implement feedback control for returning the amplitude center to the reference position.

[0030] (7) Accordingly, the flapping device of the present invention described above is characterized in that it has: a fuselage that supports the driving part; and a second biasing member that applies a force in a direction opposite to the rotation direction of the driven part as the driven part rotates, and the second biasing member is connected to the fuselage at one end side and directly or indirectly connected to the first blade shaft at the other end side, and the second biasing member is formed to be able to exert a force smaller than the force of the first biasing member and be able to exert a force that can return the amplitude center of the first biasing member to the reference position.

[0031] By adopting this configuration, the above flapping device can return the amplitude center of the first biasing member to the reference position (predetermined amplitude center) even when one end side of the first biasing member becomes a free end. That is, in the above flapping device, the first biasing member is configured as a free end, so that the amplitude center can be mechanically determined. Therefore, according to the above flapping device, it is possible to expect further improvement in control accuracy and stability.

[0032] Here, when an external rotor motor is used as the drive source, due to the rotation of the rotor in the outer peripheral part, there is a concern that the rotor interferes with each part.

[0033] (8) Accordingly, the flapping device of the present invention described above is characterized in that it has a fuselage that supports the driving part, the fuselage has a pair of support parts arranged at intervals, the drive source is arranged outside the pair of support parts, and the first biasing member and the driven part are arranged between the pair of support parts.

[0034] With the above-described configuration of the flapping-wing device, interference does not occur between the pair of drive sources, the first biasing member, and the follower portion. Therefore, for example, when an external rotor motor is used as the drive source, the flapping-wing device can suppress interference between the rotor of the external rotor motor and the first biasing member and the follower portion. Thus, even when the rotor is exposed as in the case of an external rotor motor, the flapping-wing device can suppress an increase in the size of the device.

[0035] Here, in the flapping-wing device of the present invention, when the blade is configured to tilt by a predetermined angle under the action of the wind pressure generated by the relative velocity difference between the movement of the blade and the surrounding fluid so that the vertical component of the normal vector of the blade surface facing the traveling direction faces downward, it is necessary to drive the first blade shaft while tilting the blade according to the resistance caused by the wind. For this purpose, it is necessary to enable the second blade shaft to follow the first blade shaft and rotate about the first rotation axis, and to tilt the second blade shaft relative to the first blade shaft.

[0036] (9) Therefore, the flapping-wing device of the present invention is characterized in that: an extension portion is formed at one end side of the first rotation axis so as to extend in the direction of the first rotation axis, and the second blade shaft has a suspension portion formed at one end side so as to extend toward the extension portion. The suspension portion is connected to the extension portion at one end side and can rotate integrally with the extension portion in the direction around the first rotation axis.

[0037] With the above-described configuration of the flapping-wing device, even when the second blade shaft is tilted relative to the first blade shaft (for example, when the blade is formed in a fan shape), the second blade shaft can be supported so as to be rotatable around the first rotation axis according to the tilting direction. As a result, when the blade of the flapping-wing device is subjected to the resistance caused by the wind, the blade can maintain a tilt at a predetermined angle so that the vertical component of the normal vector of the blade surface facing the traveling direction faces downward. In addition, an improvement in the design freedom and aerodynamic characteristics of the blade can be expected.

[0038] However, a torsion spring used in a flapping-wing device, for example, has a property that its natural angle gradually increases due to reasons such as uneven initial stress. Therefore, in the flapping-wing device, as the natural angle of the torsion spring increases, the flapping center of the blade shifts forward or backward, resulting in a problem that the torque in the pitching direction loses balance.

[0039] In addition, in the above-described flapping-wing device, as the torsion spring unfolds, the diameter of the torsion spring increases, and correspondingly, the spring constant decreases, which may cause a decrease in the resonance frequency during the flapping motion. As a result, there are problems such as a decrease in the lift of the flapping-wing device and difficulty in the ascent of the flapping-wing device.

[0040] In addition, since the torsion spring has the property that the spring constants are different in the rotational directions of the tightening direction and the relaxation direction, there is a problem that the above-mentioned problem occurs even when there is no initial unevenness.

[0041] (10) Therefore, the flapping wing device of the present invention is characterized in that: the first biasing member has at least a pair of torsion springs, the pair of torsion springs respectively have the same spring constant, and are connected in parallel in a manner that their torsional directions are opposite to each other.

[0042] By adopting this configuration, the flapping wing device can make the relaxation directions of the pair of torsion springs opposite to each other, so that the initial stress unevenness can be alleviated. Thus, even when the natural angles of the respective torsion springs increase, the increasing degrees of each other counteract each other, and the change in the natural angle of the torsion springs in the combined state can be suppressed.

[0043] In addition, by adopting this configuration, the restoring forces of the torsion springs counteract each other, and the change in the natural angle can be reduced. Thus, the flapping wing device can reduce the change in the diameter of each torsion spring in the combined state, and can suppress the decrease in the overall spring constant. In addition, in the above flapping wing device, since the torsion springs generate mutually reverse deformations regardless of the direction of deformation, the change in the spring constant can be eliminated.

[0044] (11) The flapping wing device of the present invention is characterized in that: it includes a fuselage that supports the driving part, the first biasing member has at least a pair of torsion springs, the pair of torsion springs respectively have the same spring constant, and are connected in parallel in a manner that their torsional directions are opposite to each other, one end side of each of the pair of torsion springs is connected to the driven part in a manner that their torsional directions are opposite to each other, and the other end side of each of them is directly or indirectly connected to the fuselage in a manner that their torsional directions are opposite to each other.

[0045] By adopting this configuration, the flapping wing device can make the relaxation directions of the pair of torsion springs opposite to each other, so that the initial stress unevenness can be alleviated. Thus, even when the natural angles of the respective torsion springs increase, the increasing degrees of each other counteract each other, and the change in the natural angle of the torsion springs in the combined state can be suppressed.

[0046] In addition, by adopting this configuration, the restoring forces of the torsion springs counteract each other, and the change in the natural angle can be reduced. Thus, the flapping wing device can reduce the change in the diameter of each torsion spring in the combined state, and can suppress the decrease in the overall spring constant. In addition, in the above flapping wing device, since the torsion springs generate mutually reverse deformations regardless of the direction of deformation, the change in the spring constant can be eliminated.

[0047] (12) The flapping wing device of the present invention is characterized in that: the first force applying member has at least a pair of torsion springs, the pair of torsion springs respectively have the same spring constant, and are connected in series in such a manner that their torsional directions are the same as each other.

[0048] By adopting this configuration in the above flapping wing device, the pair of torsion springs can cancel out the reaction forces with each other. Therefore, since the above flapping wing device can cancel out the pair of torsion springs in the relaxation direction, it can alleviate the initial stress unevenness. Thus, even when the natural angles of the respective torsion springs increase, the increasing degrees thereof counteract each other, and the change in the natural angle of the torsion springs in the combined state can be suppressed.

[0049] (13) The flapping wing device of the present invention is characterized in that: it includes a fuselage that supports the driving part, the first force applying member has at least a pair of torsion springs, the pair of torsion springs respectively have the same spring constant, and are connected in series in such a manner that their torsional directions are the same as each other, one end side of the first force applying member is connected to the driven part, and the other end side is directly or indirectly connected to the fuselage.

[0050] By adopting this configuration in the above flapping wing device, the pair of torsion springs can cancel out the reaction forces with each other. Therefore, since the above flapping wing device can cancel out the pair of torsion springs in the relaxation direction, it can alleviate the initial stress unevenness. Thus, even when the natural angles of the respective torsion springs increase, the increasing degrees thereof counteract each other, and the change in the natural angle of the torsion springs in the combined state can be suppressed.

[0051] (Advantages of the Invention)

[0052] According to the present invention, a flapping wing device that can be configured at low cost, can improve the power-to-weight ratio, and has a small structure can be provided. In addition, according to the present invention, a flapping wing device that can also be used in toys, etc. and can be realized at low cost can be provided. Description of the Drawings

[0053] Figure 1 is an overall perspective view of the flapping wing device according to the first embodiment of the present invention.

[0054] Figure 2 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.

[0055] Figure 3 is a schematic sectional view of a part of the flapping wing device according to the first embodiment of the present invention.

[0056] Figure 4 is an explanatory view of driving the blades constituting the flapping wing device according to the first embodiment of the present invention.

[0057] Figure 5 It is an explanatory diagram of the output characteristics and output region of the motor used in the flapping wing device related to the present invention.

[0058] Figure 6 Among them, (a) is an explanatory diagram of the case where the center of amplitude is offset, and (b) is an explanatory diagram of the offset control in the flapping wing device related to the first embodiment of the present invention.

[0059] Figure 7 It is an overall perspective view of the flapping wing device related to the second embodiment of the present invention.

[0060] Figure 8 It is a perspective view of the flapping wing device related to the second embodiment of the present invention observed from the obliquely rear side.

[0061] Figure 9 It is a schematic cross-sectional view of the partial structure of the flapping wing device related to the second embodiment of the present invention.

[0062] Figure 10 It is an explanatory diagram of the offset control in the flapping wing device related to the second embodiment of the present invention.

[0063] Figure 11 It is a schematic cross-sectional view of the partial structure of the flapping wing device related to the third embodiment of the present invention.

[0064] Figure 12 Among them, (a) is a perspective view of the flapping wing device related to the fourth embodiment of the present invention observed from the obliquely front side, and (b) is a perspective view of the flapping wing device in (a) observed from another direction.

[0065] Figure 13 It is a partially enlarged perspective view of the main part of the flapping wing device related to the fourth embodiment of the present invention with some parts omitted.

[0066] Figure 14 Among them, (a) is a partially enlarged perspective view of the main part of the flapping wing device related to the fifth embodiment of the present invention with some parts omitted, and (b) is a partially enlarged perspective view of the flapping wing device in (a) observed from another direction with some parts omitted.

[0067] Figure 15 It is a perspective view of an example of a highly maneuverable flapping wing device showing the structure of the flapping wing device related to the fourth and fifth embodiments of the present invention that can be applied.

[0068] (Reference Signs)

[0069] 1: Flapping wing device

[0070] 2: Blade

[0071] 3: Driving part

[0072] 7: Body

[0073] 10: Driven part

[0074] 11: First rotating shaft

[0075] 11A: Extension part

[0076] 20: First blade shaft

[0077] 21: Second blade shaft

[0078] 21A: Suspension part

[0079] 22: Blade main body

[0080] 23: Rotation limiter

[0081] 30: Drive source

[0082] 40: First biasing member

[0083] 41: Second biasing member

[0084] 42L: Torsion spring

[0085] 42R: Torsion spring

[0086] 43L: Torsion spring

[0087] 43R: Torsion spring

[0088] 60: Control unit

[0089] 70U: Support part

[0090] 70D: Support part

[0091] 100: Flapping wing device

[0092] 200: Flapping wing device

[0093] 300: Flapping wing device

[0094] 400: Flapping wing device Detailed implementation mode

[0095] Hereinafter, the flapping wing device 1 according to the first embodiment of the present invention will be described in detail with reference to the drawings. In addition, these drawings are schematic views and do not necessarily show the sizes at the correct ratio. In addition, it should be noted that the same reference numerals are given to the same constituent parts in the drawings. In addition, as Figure 1 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.

[0096] 《First Embodiment》

[0097] As shown in Figures 1 to 3 , the flapping wing device 1 has a pair of blades 2, 2 and drive units 3, 3 respectively provided with respect to the pair of blades 2, 2. The drive units 3, 3 are respectively supported by the fuselage 7. The flapping wing device 1 in the present embodiment reciprocally drives the pair of blades 2, 2 in the horizontal direction (the front - rear direction of the drawing plane) to obtain lift force toward the upper side. In addition, since the pair of blades 2, 2 and the pair of drive units 3, 3 are arranged symmetrically about the left - right direction, in the following description, without special distinction, the description will be made for the left - right side (right side), and the description of the other side (left side) will be omitted. In addition, it should be noted that in Figures 1 to 3 , the upper side in the drawing is sometimes set as the upper side (U - side), and the lower side in the drawing is set as the lower side (D - side) for description.

[0098] The fuselage 7 has a pair of support portions 70U, 70D arranged at intervals in the vertical direction. In the present embodiment, the support portions 70U, 70D are respectively formed of plate - like members.

[0099] The drive unit 3 includes a drive source 30, a driven unit 10, a first biasing member 40, etc. In addition, the drive unit 3 is connected to a control unit 60 that controls the drive of the drive source 30. In the present embodiment, the drive source 30 is composed of an outer - rotor motor in a DC motor. In addition, the illustration and description of the power supply (battery) for driving the drive source 30 are omitted.

[0100] The drive source 30 is supported via a base 31 on the outer side of the support portion 70U located on the upper side. In the present embodiment, the pair of drive sources 30, 30 are arranged symmetrically with respect to the center line C (refer to Figure 3 ).

[0101] As shown in Figure 3 , the drive shaft 32 of the drive source 30 is rotatably supported by the support portion 70U via appropriate bearings (not shown). In addition, the front - end side of the drive shaft 32 is rotatably supported by the support portion 70D via appropriate bearings (not shown). In addition, a drive gear 15 as a pinion is externally fitted to the middle portion of the drive shaft 32.

[0102] As shown in Figure 1 and Figure 2As shown, the driven part 10 is formed by a spur gear (spur gear) with a part cut off. The cut-off part of the driven part 10 is formed to prevent interference with the blade 2 or the like. The driven part 10 is supported so as to be able to rotate around the axis of the first rotation shaft 11 with respect to the support part 70U. Specifically, in the present embodiment, the first rotation shaft 11 is supported so as to be able to rotate with respect to the support part 70U and the support part 70D, and the driven part 10 is fixed to the first rotation shaft 11 by press-fitting or the like. In addition, in the present embodiment, the driven part 10 is arranged closer to the support part 70D side. The driven part 10 meshes with the drive gear 15 and can receive the power output from the drive source 30 and rotate around the axis of the first rotation shaft 11 (refer to Figure 5 ).) in the direction (also referred to as the direction around the first rotation axis).

[0103] The first rotation shaft 11 is rotatably supported by the support part 70U and the support part 70D, and an extension part 11A is formed at one end side so as to extend in the first rotation axis direction. Specifically, the extension part 11A is formed by passing one end side of the first rotation shaft 11 through the support part 70D and extending it outward. One end side (rear end side) of the extension part 11A is connected to a suspension part 21A described later.

[0104] A blade shaft holding part 50 for holding a first blade shaft 20 described later is supported on the driven part 10. The blade shaft holding part 50 rotates integrally with the driven part 10 in the direction around the first rotation axis.

[0105] In addition, a bearing 51 is supported on the blade shaft holding part 50 so as to face the radially outer side of the driven part 10. In other words, the bearing 51 is supported on the driven part 10 in a direction intersecting the first rotation shaft 11 (in the present embodiment, the orthogonal direction, hereinafter also referred to as the direction around the second axis). The first blade shaft 20 described later is supported by the bearing 51 so as to be able to rotate in the direction around the second axis.

[0106] As Figures 1 to 3 shown, the first biasing member 40 is formed by a torsion spring and is arranged between the support part 70U and the driven part 10. In addition, the first biasing member 40 is arranged around the axis of the first rotation shaft 11. The first biasing member 40 applies a force to the driven part 10 in a direction opposite to the rotation direction of the driven part 10 as the driven part 10 rotates. Specifically, one end side (front end side) of the first biasing member 40 is connected to the support part 70U, and the other end side (rear side) is connected to the driven part 10. Therefore, the first biasing member 40 can apply a force in a direction opposite to the rotation direction of the driven part 10 as the driven part 10 rotates.

[0107] The blade 2 includes a first blade shaft 20, a second blade shaft 21, a blade body 22, and the like.

[0108] The first blade shaft 20 is formed to extend along a specified axis direction (in the present embodiment, it is the radial direction of the first rotation axis 11). The first blade shaft 20 is connected to the driven part 10 at one end side and is connected in such a way that it can rotate in a direction around a second rotation axis intersecting the axis of the first rotation axis 11. Specifically, the first blade shaft 20 is rotatably supported by a bearing 51 of a blade shaft holding part 50 at one end side. Therefore, the first blade shaft 20 can rotate in a direction around the first rotation axis and in a direction around the second rotation axis. In addition, as the driven part 10 rotates, the first blade shaft 20 is applied with a force in a direction opposite to the rotation direction by the first biasing member 40. Thus, the first blade shaft 20 is excited in the rotation direction (the direction around the first rotation axis) of the driven part 10.

[0109] The second blade shaft 21 is formed to extend along a specified axis direction (in the present embodiment, it is a direction inclined at a specified inclination angle with respect to the first blade shaft 20). The second blade shaft 21 has a suspension part 21A formed at one end side so as to extend toward the extension part 11A.

[0110] The suspension part 21A is formed of, for example, a resin having a certain flexibility as a raw material. One end side of the suspension part 21A is connected to the second blade shaft 21, and the other end side is connected to the lower end side of the extension part 11A while being bent. That is, the suspension part 21A can rotate in a direction around the first rotation axis integrally with the extension part 11A. Therefore, the second blade shaft 21 can rotate in a direction around the first rotation axis integrally with the suspension part 21A. In addition, the suspension part 21A also has a function as a rotation limiter 23 described later, and this rotation limiter 23 is used to maintain the second blade shaft 21 so that it does not tilt by an angle of more than a specified angle.

[0111] Thus, 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 above-mentioned flapping device 1 can support the second blade shaft 21 in such a way that it can rotate around the first rotation axis according to the inclination direction. Thus, when the blade 2 is subjected to a resistance caused by a wind pressure generated by a relative speed difference between the movement of the blade 2 and the surrounding fluid, the above-mentioned flapping device 1 can tilt the blade 2 by a specified angle so that the vertical component of the normal vector of the blade surface facing the traveling direction faces downward. In addition, it is possible to expect an improvement in the design freedom and aerodynamic characteristics of the blade 2.

[0112] In addition, as the driven part 10 rotates, the second blade shaft 21 is applied with a force in a direction opposite to the rotation direction together with the first blade shaft 20 by the first biasing member 40. Thus, the second blade shaft 21 is excited in the rotation direction (the direction around the first rotation axis) of the driven part 10.

[0113] The blade body 22 is disposed across the first blade shaft 20 and the second blade shaft 21. In the present embodiment, the blade body 22 is formed in a substantially fan shape. The blade body 22 can swing back and forth under the drive of the drive source 30, thereby generating lift.

[0114] The control unit 60 controls the output of the driving force of the drive source 30. That is, a reciprocating motion is applied to the blade 2 by controlling the output of the driving force of the drive source 30.

[0115] Figure 4 It is an explanatory diagram showing the operation of the blade 2 when the drive source 30 is driven by the control unit 60 with a specified output. Figure 4 The examples in [figure] schematically depict the changes in the inclination state of the blade 2 when the blade 2 flaps in the forward (lower side) direction (upper part of the illustration) and when the blade 2 flaps in the backward (upper side) direction (lower part of the illustration). In addition, in the illustration, the circular mark represents the first blade shaft 20, and the triangular mark represents the rotation limiter 23 that limits the movement of the blade 2 (equivalent to the suspension part 21A in the present embodiment). In addition, various components such as a component that limits the rotation of the first rotation axis 11 can be used as the rotation limiter 23.

[0116] The blade 2 is inclined in such a way that when flapping in the forward or backward direction, an angle of attack is formed passively under the action of the resistance (wind force) received by the blade body 22. Specifically, when the blade 2 receives the resistance caused by the wind pressure generated by the relative speed difference between the movement of the blade 2 and the surrounding fluid, it is inclined by a specified angle (for example, 30 degrees) in such a way that the vertical component of the normal vector of the blade surface facing the traveling direction faces downward. In addition, the rotation limiter 23 keeps the blade 2 inclined at a specified angle. Thereby, the above-mentioned flapping wing device 1 can efficiently generate lift. In addition, the inclination angle of the blade 2 can be appropriately changed by changing the setting of the rotation limiter 23 or the like according to the flight mode.

[0117] Here, the control unit 60 can, for example, increase or decrease the lift by controlling the output of the drive source 30 in such a way 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 on the left and right by controlling the outputs of the drive sources 30, 30 in such a way that there is a difference in the amplitudes of the pair of blades 2, 2.

[0118] In addition, the control unit 60 can perform an offset control that offsets the amplitude center of the first biasing member 40 by a specified amount to one side or the other side around the first rotation axis.

[0119] Figure 6 (a) in [figure] is an explanatory diagram of the case where the amplitude center of the first biasing member 40 is offset. In addition, it should be noted that inFigure 6 In (a) of FIG. [reference number not provided], the angle that offsets the amplitude center of the first biasing member 40 is exaggeratedly depicted for ease of understanding. The offset control is a control that offsets the amplitude center of the first biasing member 40 in the front-rear direction (the solid line position on the front side in this embodiment). That is, the offset control is a control that offsets the center of lift in the front-rear direction (the front side in this embodiment).

[0120] Specifically, as Figure 6 shown in (b) of FIG. [reference number not provided], the 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 the drive source 30. 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. In addition, in the PWM control that is actually widely used in motor control, it is only necessary to replace it with setting a difference in the motor drive duty ratio in the forward path and the return path. That is, the amplitude center of the first biasing member 40 is offset (refer to Figure 6 (a) of FIG. [reference number not provided]). Thereby, the control unit 60 can generate a torque in the pitching direction. Here, the angle that offsets the amplitude center of the first biasing member 40 can be, for example, 5 to 10 degrees. In addition, in the flapping-wing device 1 of the first embodiment, when generating the above offset, it is necessary to overcome the first biasing member 40 and increase the output of the drive source 30. Additionally, according to the flight mode of the flapping-wing device 1, the offset amounts of the pair of drive sources 30, 30 can be the same, or can also be different from each other.

[0121] 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 way 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 way that the direction of the speed difference between the left and right blades 2, 2 is opposite.

[0122] Figure 5 FIG. [reference number not provided] is an explanatory diagram of the output characteristics in the drive source 30 and the output region utilized in the flapping-wing device 1 of the present invention. As shown in the figure, when the drive source 30 uses a motor (an outer-rotor motor in this embodiment), at the reversal (the switching between the forward stroke and the return stroke) 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, due to the restoring force of the first biasing member 40, the reciprocating motion is autonomously reversed at the reversal end of the reciprocating motion of the blade 2.

[0123] Therefore, in the present embodiment, the control unit 60 performs the following control: before a predetermined time when the rotational speed of the drive source 30 becomes zero during the forward or reverse rotation switching of the drive source 30, the drive source 30 is stopped from outputting the driving force. Here, the predetermined time can be arbitrarily set according to the characteristics of the drive source 30 used (for example, the output efficiency). In addition, the control unit 60 performs the following control together with the above control: after a predetermined time when the forward or reverse movement of the blade 2 is switched by the restoring force of the first biasing member 40, the drive source 30 restarts outputting the driving force.

[0124] Thereby, it is possible to stop driving by the drive source 30 in the part 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 flapping wing device 1 can efficiently reciprocate the blade 2. In addition, the above flapping wing device 1 performs the following control: at the moment when the forward or reverse movement of the pair of blades 2, 2 is switched by the restoring force of the first biasing member 40, the drive source 30 restarts driving. Thereby, the above flapping wing device 1 can vibrate the blade 2 in the region where the angular velocity of the blade 2 near the flapping center is large. In addition, the above flapping wing device 1 can efficiently perform the flapping wing motion without increasing the capacity of the drive source 30. Therefore, it is possible to expect miniaturization of the above flapping wing device 1.

[0125] The above is the configuration of the flapping wing device 1 according to the first embodiment of the present invention. In addition, in the above, the configurations of the symmetrically arranged parts are the same, so the description is omitted. Next, the operation and effect of the flapping wing device 1 according to an embodiment of the present invention will be described below.

[0126] The above flapping wing device 1 can vibrate the first blade shaft 20 in the direction around the first rotation axis by the biasing force of the first biasing member 40. Therefore, the above flapping wing 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. Therefore, a strong lift force can be obtained. In addition, the first biasing member 40 can preferably use a member such as a torsion spring that can apply a torque in the torsional direction.

[0127] In addition, the above flapping wing device 1 can independently control the driving of the pair of drive sources 30, 30, and thus can fly in all directions. Here, the drive source 30 can use various motors, etc., but a brushless DC motor that is easy to reverse and has a high power-to-weight ratio can be preferably used. Thereby, battery driving becomes easy and control can also be easily performed.

[0128] In addition, in the present embodiment, the drive source 30 of the flapping device 1 is constituted by an outer-rotor motor in a DC motor. Therefore, the flapping device 1 can increase the inertia generated by the rotor constituting the motor. As a result, the 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 flapping device 1 can reduce the influence of external disturbances (such as air flow) on the flapping device 1, and it is possible to expect further stabilization of the control.

[0129] In addition, by using an outer-rotor motor that is less expensive than an inner-rotor motor, the flapping device 1 can reduce the cost of the drive source 30. Therefore, by replacing the pair of left and right drive sources 30, 30 with outer-rotor motors, the flapping device 1 can expect to further reduce the cost.

[0130] In addition, the flapping device 1 has a fuselage 7 that supports the drive source 30, and the fuselage 7 has a pair of support portions 70U, 70D arranged at intervals. In addition, the drive source 30 is arranged outside the pair of support portions 70U, 70D, and the first biasing member 40 and the driven portion 10 are arranged between the pair of support portions 70U, 70D.

[0131] As a result, in the flapping device 1, the drive source 30 does not interfere with the first biasing member 40 and the driven portion 10. Therefore, in the flapping device 1, for example, when an outer-rotor motor is used as the drive source 30, it is possible to suppress interference between the rotor of the outer-rotor motor and the first biasing member 40 and the driven portion 10. In this way, even when the rotor is exposed like an outer-rotor motor, the flapping device 1 can suppress the enlargement of the device.

[0132] The above is the configuration and effects of the flapping device 1 according to the first embodiment of the present invention. Next, the flapping device 100 according to the second embodiment of the present invention will be described in detail. In addition, compared with the above flapping device 1, the flapping device 100 according to the second embodiment has the same configuration except that the connection method of the first biasing member 40 and the arrangement of each component are partially different. Therefore, 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 device 1. In addition, since the flapping 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.

[0133] However, in the flapping-wing device 1 according to the above-described first embodiment, one side of the first biasing member 40 is connected to the support portion 70U, and the other side is connected to the driven portion 10. 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 K of a torsion spring or the like used for the first biasing member 40. However, when the spring constant K of the first biasing member 40 is increased, the restoring force also becomes stronger, so the load becomes larger, and there is a concern that it becomes difficult to flap the first blade shaft 20 and the second blade shaft 21. As a result, there is a concern that the lift is reduced. Therefore, an object of the second embodiment is to provide a flapping-wing device 100 that can further increase the lift and stabilize the control by suppressing the concerns in the first embodiment.

[0134] 《Second Embodiment》

[0135] As Figures 7 to 9 shown, the flapping-wing device 100 according to the second embodiment includes a pair of blades 2, 2 and drive units 3, 3 provided corresponding to the pair of blades 2, 2, respectively. In addition, the drive unit 3 includes a drive source 30, a driven portion 10, a first biasing member 40, and the like. Further, the drive unit 3 is connected to a control unit 60 that controls the drive of the drive source 30.

[0136] One end side of the first biasing member 40 in the flapping-wing device 100 is connected to the driven portion 10, 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 40 is connected to the driven portion 10, and the other end side is connected to the blade shaft holding portion 50. That is, one end side of the first biasing member 40 is not fixed to the fuselage 7 constituting the flapping-wing device 100, but is fixed to the driven portion 10. In other words, one end side of the first biasing member 40 becomes a free end. Further, in the second embodiment, the driven portion 10 is supported so as to be rotatable relative to the first rotation shaft 11.

[0137] The above is the configuration of the flapping-wing device 100 according to the second embodiment of the present invention, but the flapping-wing device 100 can shift the amplitude center of the first biasing member 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 shift control.

[0138] As Figure 10 shown, the shift control can be performed by applying an offset of a specified amount T to the drive voltage waveform (output waveform) of the drive source 30. In addition, the offset amount of the drive source 30 can be appropriately changed according to the flight mode of the flapping-wing device 100.

[0139] Thus, the above flapping device 100 can easily perform offset control by applying an offset of a prescribed amount T to the drive voltage waveform of the drive source 30. Therefore, according to the above flapping device 100, both high-precision control and stable control can be expected. In addition, since one end side of the first biasing member 40 becomes a free end in the flapping device 100 according to the second embodiment, an offset can be easily applied to the flapping amplitude center without resisting the restoring force of the first biasing member 40. That is, even in a structure where the spring constant K of the first biasing member 40 is larger and the restoring force is larger, a large motor power is not required to apply an offset to the flapping amplitude center. Therefore, a high flapping frequency and a reduction in motor power during control can be achieved simultaneously.

[0140] The above is the configuration of the flapping device 100 according to the second embodiment of the present invention. Next, the operation and effects of the flapping device 100 will be described in detail.

[0141] As described above, even when a torque (acting force) is applied to the first biasing member 40, the flapping device 100 can vibrate the first blade shaft 20 without being affected by the restoring force of the first biasing member 40. That is, the above flapping device 100 can directly apply a torque to the first blade shaft 20. Thereby, stable output control of the drive source 30 can be expected. In addition, the first biasing member 40 can preferably be a member such as a torsion spring that can apply a torque in the torsional direction.

[0142] In addition, in the above flapping device 100, since the second blade shaft 21 can rotate about the first rotation axis, the stroke angle of the blade 2 that is driven by driving the first blade shaft 20 by the drive source 30 and is affected by the wind is passively defined as the angle of attack of the blade 2. Thus, the above flapping device 100 can flexibly capture the wind through the blade main body 22, and thereby can efficiently obtain lift. The drive source 30 can use various motors, etc., but a brushless DC motor that is easy to reverse and has a high power-to-weight ratio can be preferably used. Thereby, battery driving becomes easy and control can also be easily performed.

[0143] Here, in the above offset control, one end side of the first biasing member 40 becomes a free end. Therefore, there is a concern that the amplitude center of the first biasing member 40 after the offset may deviate from the predetermined amplitude center (also referred to as the reference position) as the first biasing member 40 vibrates. Therefore, as Figure 11As shown, the flapping wing device 200 according to the third embodiment is further provided with a second biasing member 41 to return the amplitude center of the deflected first biasing member 40 to the reference position. Hereinafter, the flapping wing device 200 according to the third embodiment will be described in detail. In addition, since the flapping wing device 200 according to the third embodiment is provided with the second biasing member 41 with respect to the flapping wing device 100 according to the second embodiment, the description of the parts identical to those of the flapping wing device 100 according to the second embodiment will be omitted. In addition, since the flapping wing device 200 according to the third embodiment is configured symmetrically about the left and right, one side will be described and the description of the other side will be omitted.

[0144] 《Third Embodiment》

[0145] As Figure 11 shown, the flapping wing device 200 according to the third embodiment, in addition to having the configuration of the flapping wing device 100 according to the second embodiment (refer to Figure 9 ), further has a second biasing member 41.

[0146] The second biasing member 41 uses, for example, a torsion spring. The second biasing member 41 applies a force in the direction opposite to the rotation direction of the driven part 10 as the driven part 10 rotates. Specifically, the second biasing member 41 is connected to the fuselage 7 (the support part 70D in this embodiment) on one end side and is connected to the driven part 10 on the other end side.

[0147] In addition, the second biasing member 41 can exert a force smaller than the force of the first biasing member 40 and can exert a force that can return the amplitude center of the first biasing member 40 to the reference position. For example, the second biasing member 41 uses a torsion spring having a spring constant smaller than that of the first biasing member 40. Therefore, the influence of the second biasing member 41 on the first biasing member 40 is limited.

[0148] Here, the spring constant of the second biasing member 41 can utilize various spring constants that can exert a force capable of returning the amplitude center of the first biasing member 40 to the reference position. In addition, the spring constant of the second biasing member 41 is preferably determined in consideration of the balance between the influence on the first biasing member 40 and the force for returning the amplitude center to the reference position.

[0149] In this way, the flapping wing device 200 according to the third embodiment can return the amplitude center of the first biasing member 40 to the reference position (predetermined amplitude center) even when one end side of the first biasing member 40 becomes a free end. Therefore, according to the above flapping wing device 200, it is possible to expect further improvement in control accuracy and stability.

[0150] However, the torsion springs used in the flapping wing devices 1, 100, 200 (also simply referred to as the flapping wing device 1, etc.) may, for example, cause the natural angle to gradually increase due to reasons such as uneven initial stress. Therefore, in the flapping wing device 1, etc., as the natural angle of the torsion spring increases, the flapping center of the blade 2 shifts forward or backward, which may disrupt the torque balance in the pitching direction. Therefore, for the flapping wing device 1, etc., in order to further optimize the torque balance generated by using the torsion spring, it is preferable to seek further optimization of the structure based on considering the characteristics of the torsion spring.

[0151] In addition, in addition to the above-mentioned single-degree-of-freedom flapping wing devices 1, etc., it is also possible to consider a more maneuverable flapping wing device with the degree of freedom of the blade 2 increased to two degrees of freedom. Specifically, it is possible to consider Figure 15 a flapping wing device such as the flapping wing device 1000 shown. The flapping wing device 1000 has blades 1002, 1002 and a pair of drive units 1003, 1003 provided corresponding to the blades 1002, 1002. The drive unit 1003 includes: a first drive source 1030U, a second drive source 1030D, a first driven unit 1010U that rotates around a first rotation axis by the first drive source 1030U, a second driven unit 1010D that rotates around a second rotation axis by the second drive source 1030D, a first biasing member 1040U that biases the first driven unit 1010U in a direction opposite to the rotation direction of the first driven unit 1010U, a second biasing member 1040D that biases the second driven unit 1010D in a direction opposite to the rotation direction of the second driven unit 1010D, and a control unit 1060. The blade 1002 has: a first blade shaft 1020 connected to the first driven unit 1010U and capable of rotating around a third rotation axis intersecting the first rotation axis, a second blade shaft 1021 connected to the second driven unit 1010D and capable of rotating around a fourth rotation axis intersecting the second rotation axis, and a blade body 1022. In a highly maneuverable flapping wing device such as Figure 15 the flapping wing device 1000 shown, either one or both of the first biasing member 1040U and the second biasing member 1040D (both the first biasing member 1040U and the second biasing member 1040D in the illustrated example) can also be constituted by a torsion spring.

[0152] In such a highly maneuverable flapping wing device (such as the flapping wing device 1000), in addition to the above-mentioned flapping wing device 1, etc., there are also flapping wing devices in which, for example, the center of the blade 2 shifts upward or downward. Therefore, in highly maneuverable flapping wing devices such as the flapping wing device 1000, the center position of the angle of attack of the blade 2 shifts, which may disrupt the balance of the propulsive force in the front-rear direction. Therefore, in the case of a highly maneuverable flapping wing device such as the flapping wing device 1000 that uses a torsion spring, it is possible to seek further optimization of the structure based on considering the characteristics of the torsion spring.

[0153] In addition, in the flapping device 1 or the highly maneuverable flapping device 1000 described above, when the torsion spring is unwound and the diameter of the torsion spring increases, the spring constant decreases accordingly, which may cause a decrease in the resonance frequency during the flapping motion. As a result, it is possible to reduce the lift of the flapping device 1 or the like and reduce the ascending stability of the flapping device 1 or the like. Therefore, in order to further improve the ascending stability determined by the characteristics of the torsion spring while using the torsion spring as in the flapping device 1 or the flapping device 1000 or the like, it is possible to further optimize the structure in consideration of the characteristics of the torsion spring.

[0154] In addition, the torsion spring has the property that the spring constant is different in the rotational direction of the tightening direction and the rotational direction of the relaxation direction. As a result, even when there is no initial unevenness, as described above, the torque in the pitching direction is unbalanced or the propulsive force is unbalanced. Therefore, in a flapping device that uses a torsion spring such as the flapping device 1 or a highly maneuverable flapping device (for example, the flapping device 1000), there is a problem that it may affect the motion stability determined by the unique characteristics of the torsion spring.

[0155] Therefore, in the flapping device 300 according to the fourth embodiment, as Figure 12 and Figure 13 ( Figure 12 the enlarged perspective view near the first biasing member 40 on the right side in

[0156] "Fourth Embodiment"

[0157] As Figure 12 in (a) of Figure 12 in (b) of Figure 13 and

[0158] shown, the first biasing member 40 is divided into a pair of torsion springs 42L and 42R. The pair of torsion springs 42L and 42R each have the same spring constant. The pair of torsion springs 42L and 42R are connected in parallel in a manner such that their twisting directions are opposite to each other (also referred to as reverse winding). Specifically, the pair of torsion springs 42L and 42R are arranged in the vertical direction around the first rotation axis 11 in a manner such that their twisting directions are opposite to each other.In addition, one end side of each of a pair of torsion springs 42L and 42R is connected to the driven part 10 in such a way that their torsional directions are opposite to each other, and the other end side of each is connected to the fuselage 7 in such a way that their torsional directions are opposite to each other. Therefore, the pair of torsion springs 42L and 42R can apply a force in a direction opposite to the rotational direction of the driven part 10 to the driven part 10 as the driven part 10 rotates. Here, the connection position of either one or both of the one end side and the other end side of the torsion springs 42L and 42R can be adjusted. Thereby, the torsion springs 42L and 42R can adjust their respective initial opening angles. In addition, the other end side of the torsion springs 42L and 42R can be connected not only directly to the fuselage 7 but also indirectly.

[0159] In addition, when the spring constant of the first biasing member 40 in the first embodiment is set to K, the spring constants of the torsion springs 42L and 42R in the fourth embodiment are each 1 / 2K, which is half of it. In other words, with respect to the spring constant K of the first biasing member 40 before division (also referred to as the original first biasing member 40), the torsion springs 42L and 42R each have a spring constant of 1 / 2K, which is half of it. Therefore, by connecting the torsion springs 42L and 42R in parallel in such a way that their torsional directions are opposite to each other, the torsion springs 42L and 42R have the same spring constant K as the original first biasing member 40 in the combined state. Thereby, the torsion springs 42L and 42R can apply the same force to the driven part 10 in a direction opposite to the rotational direction of the driven part 10 as the driven part 10 rotates as the original first biasing member 40 does.

[0160] In addition, in the flapping wing device 300 according to the fourth embodiment, the first biasing member 40 has a pair of torsion springs 42L and 42R, but it may be formed by an even number of torsion springs 42L and 42R, and may also be composed of two or more pairs of torsion springs 42L and 42R. In this case, the spring constant of each of the torsion springs 42L and 42R may be equally divided according to the number of torsion springs. In addition, the spring constant can be changed to various values according to the type of the flapping wing device 300. In addition, the configuration of the flapping wing device 300 according to the fourth embodiment can also be applied to the type of the flapping wing device 100 (free end specification) according to the second embodiment.

[0161] In addition, although not shown, a highly maneuverable flapping wing device 1000 (refer to Figure 15 ) may also be respectively composed of at least a pair of torsion springs 42L and 42R for the first biasing member 1040U and the second biasing member 1040D, and connected in parallel in such a way that their torsional directions are opposite to each other. In addition, according to the embodiment, at least a pair of torsion springs 42L and 42R may be used to form either one or both of the first biasing member 1040U and the second biasing member 1040D (components different from the second biasing member 41 in the third embodiment).

[0162] The above is the configuration of the flapping wing device 300 according to the fourth embodiment of the present invention. Next, the effects achieved by the flapping wing device 300 according to the fourth embodiment will be described.

[0163] As described above, the flapping wing device 300 according to the fourth embodiment is characterized in that: the first biasing member 40 has at least a pair of torsion springs 42L and 42R, and the pair of torsion springs 42L and 42R have the same spring constant respectively, and are connected in parallel in a manner that their torsional directions are opposite to each other.

[0164] In addition, the flapping wing device 300 according to the fourth embodiment is characterized in that: it includes a fuselage 7 that supports the drive unit 3, the first biasing member 40 has at least a pair of torsion springs 42L and 42R, and the pair of torsion springs 42L and 42R have the same spring constant respectively, and are connected in parallel in a manner that their torsional directions are opposite to each other. One end side of each of the pair of torsion springs 42L and 42R is connected to the driven part 10 in a manner that their torsional directions are opposite to each other, and the other end side of each is directly or indirectly connected to the fuselage 7 in a manner that their torsional directions are opposite to each other.

[0165] By adopting the above configuration, the flapping wing device 300 according to the fourth embodiment can make the relaxation directions of the pair of torsion springs 42L and 42R opposite to each other, so that the initial stress unevenness can be alleviated. Thus, in the flapping wing device 300, even when the natural angles of the respective torsion springs 42L and 42R increase, the increasing degrees of each other counteract each other, so that the change in the natural angle of the torsion springs 42L and 42R in the combined state can be suppressed.

[0166] In addition, by adopting the above configuration, the restoring forces of the torsion springs 42L and 42R counteract each other, and the change in the natural angle can be reduced. Thus, the flapping wing device 300 can reduce the change in the diameter of each of the torsion springs 42L and 42R in the combined state, so that the reduction of the overall spring constant can be suppressed. In addition, since the torsion springs 42L and 42R generate deformations in opposite directions regardless of the direction of deformation, the flapping wing device 300 can eliminate the change in the spring constant.

[0167] In addition, in the highly maneuverable flapping wing device 1000, by configuring the first biasing member 1040U or the second biasing member 1040D with at least a pair of torsion springs 42L and 42R and connecting them in parallel as in the above fourth embodiment, the same effects as those of the fourth embodiment can also be obtained in the highly maneuverable flapping wing device 1000. Furthermore, since the highly maneuverable flapping wing device 1000 can suppress the deviation of the center position of the angle of attack of the blade 2, it can also suppress the imbalance of the propulsive force in the front-rear direction.

[0168] The above is the configuration and effects of the flapping wing device 300 according to the fourth embodiment. Next, a detailed description will be given of the flapping wing device 400 according to the fifth embodiment in which the torsion springs 43L and 43R are connected in series. In addition, the flapping wing device 400 according to the fifth embodiment has a structure in which the torsion springs 43L and 43R in the flapping wing device 1 according to the fourth embodiment are connected in series. Therefore, the description of the parts that are the same as those of the flapping wing devices 1 and 300 according to the first embodiment and the fourth embodiment is omitted. In addition, the flapping wing device 400 according to the fifth embodiment is configured symmetrically about the left and right. Therefore, only one side will be described, and the description of the other side will be omitted. In addition, Figure 14 in (a) and Figure 14 in (b), the drive unit 3, the blade 2, the first blade shaft 20, the second blade shaft 21, etc. are omitted and depicted, but these parts can be configured in the same manner as in the first to third embodiments.

[0169] 《Fifth Embodiment》

[0170] Figure 14 in (a) and Figure 14 in (b) are perspective views in which the periphery of the torsion springs 43L and 43R in the flapping wing device 400 is enlarged and a part is cut away. As shown in the figure, the first biasing member 40 is divided into a pair of torsion springs 43L and 43R. The pair of torsion springs 43L and 43R each have the same spring constant. The pair of torsion springs 43L and 43R are connected in series in such a manner that their torsional directions are the same. Specifically, the pair of torsion springs 43L and 43R are arranged in the vertical direction around the first rotation axis 11 in such a manner that their torsional directions are the same, and one ends of each other are connected to each other by, for example, welding.

[0171] In addition, one end side of the integrated torsion springs 43L and 43R is connected to the driven part 10, and the other end side is connected to the fuselage 7. Therefore, the pair of torsion springs 43L and 43R can apply a force in a direction opposite to the rotation direction of the driven part 10 as the driven part 10 rotates. Here, the connection position of either one or both of the one end side and the other end side of the torsion springs 43L and 43R can be adjusted. Thereby, the torsion springs 43L and 43R can adjust their respective initial opening angles. In addition, the other end side of the torsion springs 43L and 43R can be connected not only directly to the fuselage 7 but also indirectly.

[0172] In addition, when the spring constant of the first biasing member 40 in the first embodiment is set to K, the spring constants of the torsion springs 43L and 43R in the fifth embodiment are 2K, which is twice that value. In other words, relative to the spring constant K of the first biasing member 40 before division (also referred to as the original first biasing member 40), the torsion springs 43L and 43R each have a spring constant of 2K, which is twice that value. Therefore, by connecting the torsion springs 43L and 43R in series in the same torsional direction, the torsion springs 43L and 43R have the same spring constant K as the original first biasing member 40 in the combined state. Thus, the torsion springs 43L and 43R can apply the same acting force as the original first biasing member 40 to the driven part 10 in a direction opposite to the rotational direction of the driven part 10 as the driven part 10 rotates.

[0173] In addition, in the flapping-wing device 400 according to the fifth embodiment, the first biasing member 40 has a pair of torsion springs 43L and 43R, but it may be formed by an even number of torsion springs 43L and 43R, or may be composed of two or more pairs of torsion springs 43L and 43R. In this case, the spring constants of the torsion springs 43L and 43R are multiplied by the same multiple according to the number of springs. In addition, the spring constant can be changed to various values according to the type of the flapping-wing device 400. In addition, the configuration of the flapping-wing device 400 according to the fifth embodiment can also be applied to the type of the flapping-wing device 100 (free-end specification) according to the second embodiment.

[0174] In addition, although not shown, a highly maneuverable flapping-wing device 1000 (see Figure 15 ) may be configured such that the first biasing member 1040U and the second biasing member 1040D are each composed of at least one pair of torsion springs 43L and 43R, and are connected in series in the same torsional direction, similar to the flapping-wing device 300 according to the fifth embodiment. In addition, according to the embodiment, at least one pair of torsion springs 43L and 43R may be used to form either or both of the first biasing member 1040U and the second biasing member 1040D (components different from the second biasing member 41 in the third embodiment).

[0175] The above is the configuration of the flapping-wing device 400 according to the fifth embodiment of the present invention. Next, the effects achieved by the flapping-wing device 400 according to the fifth embodiment will be described.

[0176] As described above, the flapping-wing device 400 according to the fifth embodiment is characterized in that the first biasing member 40 has at least one pair of torsion springs 43L and 43R, the pair of torsion springs 43L and 43R each have the same spring constant, and are connected in series in the same torsional direction.

[0177] In addition, the flapping-wing device 400 according to the fifth embodiment is characterized in that: it includes a fuselage 7 that supports the drive unit 3, and the first biasing member 40 has at least a pair of torsion springs 43L and 43R. The pair of torsion springs 43L and 43R respectively have the same spring constant and are connected in series in such a way that their torsional directions are the same. One end side of the first biasing member 40 is connected to the driven part 10, and the other end side is directly or indirectly connected to the fuselage 7.

[0178] By adopting the above configuration in the flapping-wing device 400 according to the fifth embodiment, the pair of torsion springs 43L and 43R can cancel each other's reaction forces. Therefore, since the pair of torsion springs 43L and 43R can cancel each other in the relaxation direction, the initial stress unevenness can be alleviated. Thus, in the flapping-wing device 400, even when the natural angles of the respective torsion springs 43L and 43R increase, the degrees of increase of each other counteract each other, so that the change in the natural angle of the torsion springs 43L and 43R in the combined state can be suppressed.

[0179] In addition, in the highly maneuverable flapping-wing device 1000, by forming the first biasing member 1040U or the second biasing member 1040D with at least a pair of torsion springs 43L and 43R and connecting them in series as in the above fifth embodiment, the same effects as those of the fifth embodiment can also be obtained in the highly maneuverable flapping-wing device 1000. Furthermore, since the highly maneuverable flapping-wing device 1000 can suppress the deviation of the center position of the angle of attack of the blade 2, it can also suppress the imbalance of the propulsive force in the front-rear direction.

[0180] The above are the configurations and effects of the flapping-wing devices 1, 100, 200, 300, and 400 according to the first to fifth embodiments of the present invention. However, the flapping-wing devices 1, 100, 200, 300, and 400 of the present invention are not limited to the above embodiments and can be variously deformed.

[0181] For example, the pair of blades 2, 2 can be formed into various shapes and sizes. In addition, 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. In this case, as long as a drive source 30 is additionally provided corresponding to the blade 2. In addition, 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.

[0182] In addition, in the present embodiment, the case where the drive sources 30, 30 use an external rotor motor in a DC motor is illustrated, but the drive sources 30, 30 can use various motors that can exert a driving force, etc. For example, the drive sources 30, 30 can also be composed of an internal rotor motor in a DC motor.

[0183] In addition, in the present embodiment, the driven part 10 uses spur gears (straight gears), and the drive gear 15 as a pinion drives these driven parts, but the present invention is not limited thereto. The driven part 10 can use various types of driven parts. For example, the driven part 10 can also be formed by a pulley or the like and driven by a transmission belt or the like. In addition, depending on the type of the driven part 10, the drive gear 15 can use not only gears but also various types.

[0184] In addition, in the present embodiment, torsion springs are used as the first biasing member 40 and the second biasing member 41, but the present invention is not limited thereto. The first biasing member 40 and the second biasing member 41 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 40 and the second biasing member 41, but different types of biasing members can also be used separately. In addition, the arrangement of the first biasing member 40 and the second biasing member 41 can be variously changed within the scope of the present invention. In addition, in the present embodiment, the control is unified by a single control unit 60, but the control unit 60 can also be composed of multiple units and control can be differentiated by function, etc.

[0185] In addition, in the present embodiment, the second blade shaft 21 is connected to the first rotating shaft 11 via the suspension part 21A and the extension part 11A, but the second blade shaft 21 can be connected not only via the suspension part 21A and the extension part 11A, but also in various ways that directly or indirectly connect to the first rotating shaft 11. In addition, the suspension part 21A and the extension part 11A can be formed into various shapes and sizes according to the formation direction of the second blade shaft 21.

[0186] In addition, in the present embodiment, control is performed to stop the drive source 30 from outputting driving force before a specified time when the rotational speed of the drive source 30 becomes 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: the drive source 30 restarts outputting driving force at the moment when the reciprocating or returning movement of the blade 2 is switched by the restoring force of the first biasing member 40, but the timing of restarting outputting driving force can also be appropriately changed according to the characteristics of the motor or the like used. In addition, for the offset amount in the offset control performed by the control unit 60, various offset amounts can be set according to the flight mode of the flapping wing devices 1, 100, and 200.

[0187] In addition, in the present embodiment, the control unit 60 tilts the blade 2 by a specified angle according to the resistance received by the blade surface (blade main body 22) of the blade 2 so that the vertical component of the normal vector of the blade surface facing the traveling direction points downward. However, the angle by which the blade 2 is tilted can be set to various angles by changing the setting of the rotation limiter 23 according to the flight mode, flight environment, etc. For example, the angle by which the blade 2 is tilted can be adjusted by changing the shape, size, or material of the suspension unit 21A. 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.

[0188] In addition, in the fourth and fifth embodiments, an example is shown in which the first biasing member 40 is constituted by torsion springs 42L and 42R (fourth embodiment) or torsion springs 43L and 43R (fifth embodiment) each having the same spring constant. However, as long as changes in the natural angles of the torsion springs 42L and 42R and the torsion springs 43L and 43R can be suppressed, the spring constants of the torsion springs 42L and 42R and the torsion springs 43L and 43R may be different from each other, or their shapes, sizes, etc. may be different. In addition, the spring constant in the state where the torsion springs 42L and 42R and the torsion springs 43L and 43R are combined can be set to various values according to the generated acting force. In addition, in the fourth and fifth embodiments, a pair of torsion springs 42L and 42R and torsion springs 43L and 43R are used, but the torsion springs 42L and 42R and the torsion springs 43L and 43R are not limited to a pair, and may be constituted by two or more pairs of even numbers. In addition, the same configuration as that of the fourth and fifth embodiments can also be adopted in the highly maneuverable flapping wing device 1000.

[0189] 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 without departing from the scope of protection according to its teachings and spirit, which is easily understood by those skilled in the art.

[0190] (Industrial Applicability)

[0191] 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, comprising: a pair of blades; and a driving unit provided corresponding to each of the pair of blades, wherein the driving unit includes: a driving source; a driven part that rotates about a first rotation axis by receiving power output from the driving source; a first biasing member that applies a force in a direction opposite to the rotation direction of the driven part as the driven part rotates; and a control unit that controls the output of the driving force of the driving source, wherein the blade has: a first blade shaft extending in a specified axis direction, connected to the driven part at one end side, and connected in a manner capable of rotating about a second rotation axis that intersects the first rotation axis; a second blade shaft extending in a direction intersecting the first blade shaft, directly or indirectly connected to the driven part at one end side, and connected in a manner capable of rotating about the first 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, comprising: a pair of blades; and a driving unit provided corresponding to each of the pair of blades, wherein the driving unit includes: a driving source; a driven part that rotates about a first rotation axis by receiving power output from the driving source; a first biasing member that applies a force in a direction opposite to the rotation direction of the driven part as the driven part rotates; and a control unit that controls the output of the driving force of the driving source, wherein the blade has: a first blade shaft extending in a specified axis direction, connected to the driven part at one end side, and connected in a manner capable of rotating about a second rotation axis that intersects the first rotation axis; a second blade shaft extending in a direction intersecting the first blade shaft, directly or indirectly connected to the driven part at one end side, and connected in a manner capable of rotating about the first 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 driven part at one end side and directly or indirectly connected to the first blade shaft at the other end side.

3. The flapping wing device according to claim 1 or 2, characterized in that, The driving source is constituted by an outer rotor motor in a DC motor.

4. The flapping wing device according to claim 1 or 2, characterized in that, The control unit performs the following control: before a specified time when the rotational speed of the driving source becomes zero during the forward or reverse rotation switching of the driving source, the driving source is stopped from outputting the driving force, and performs the following control: after a specified time when the reciprocating or returning movement of the blade is switched by the restoring force of the first biasing member, the driving source is restarted to output the driving force.

5. The flapping wing device according to claim 1 or 2, characterized in that, The control unit is capable of performing offset control that 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, and the offset control is performed by applying a specified amount of offset to the drive voltage waveform of the driving source.

6. The flapping wing device according to claim 1 or 2, characterized in that, The flapping device has a rotation limiter that is configured to maintain the blades at a prescribed angle of inclination due to the resistance caused by the wind pressure, such that the vertical component of the normal vector of the blade surface facing the traveling direction points downward. The wind pressure is generated by the relative velocity difference between the movement of the blades and the surrounding fluid.

7. The flapping wing device according to claim 2, wherein comprising: a fuselage that supports the drive unit; and a second biasing member that applies a force in a direction opposite to the rotational direction of the driven unit as the driven unit rotates. One end side of the second biasing member is connected to the fuselage, and the other end side is directly or indirectly connected to the first blade shaft. The second biasing member is configured to exert a force smaller than that of the first biasing member and to exert a force capable of returning the amplitude center of the first biasing member to the reference position.

8. The flapping wing device according to claim 1 or 2, wherein The flapping device has a fuselage that supports the drive unit. The fuselage has a pair of support portions arranged at an interval. The drive source is arranged outside the pair of support portions. The first biasing member and the driven unit are arranged between the pair of support portions.

9. The flapping wing device according to claim 1 or 2, wherein An extension portion is formed at one end side of the first rotation axis so as to extend in the direction of the first rotation axis. One end side of the second blade shaft has a suspension portion formed so as to extend toward the extension portion. One end side of the suspension portion is connected to the extension portion and is capable of rotating integrally with the extension portion in a direction around the first rotation axis.

10. The flapping wing device according to claim 1 or 2, wherein The first biasing member has at least a pair of torsion springs. The pair of torsion springs each have the same spring constant and are connected in parallel with their torsional directions opposite to each other.

11. The flapping wing device according to claim 1, wherein The flapping device includes a fuselage that supports the drive unit. The first biasing member has at least a pair of torsion springs. The pair of torsion springs each have the same spring constant and are connected in parallel with their torsional directions opposite to each other. One end side of each of the pair of torsion springs is connected to the driven unit with their torsional directions opposite to each other, and the other end side of each is directly or indirectly connected to the fuselage with their torsional directions opposite to each other.

12. The flapping wing device according to claim 1 or 2, wherein The first biasing member has at least a pair of torsion springs. The pair of torsion springs each have the same spring constant and are connected in series with their torsional directions the same.

13. The flapping wing device according to claim 1, wherein The flapping device includes a fuselage that supports the drive unit. The first biasing member has at least a pair of torsion springs. The pair of torsion springs each have the same spring constant and are connected in series with their torsional directions the same. One end side of the first biasing member is connected to the driven unit, and the other end side is directly or indirectly connected to the fuselage.

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