JP2005119658A - Ornithopter and flapping flight method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve propelling efficiency of an ornithopter including a micro aerial vehicle. <P>SOLUTION: This ornithopter is provided so as to increase amplitude of a feather ring of a flapping wing continuously formed on a flapping of the flapping wing toward an wing end of the flapping wing from a wing root of the flapping wing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flapping airplane and a flapping flight method, and is suitable for human-powered flapping airplane and flapping flight by human power. The present invention is also suitable for a flapping airplane with a motor and a small flying vehicle (MicroAerialVehicle).

  The flapping motion in a flapping airplane is the main motion (hereinafter referred to as “flapping”) for raising and lowering the flapping wing, and the secondary motion (hereinafter referred to as “feathering”) for appropriately changing the pitch angle of the flapping wing. To obtain thrust and lift. In the flapping wing down shown in FIG. 8 (a), feathering is coupled so that the pitch angle α of the flapping wing passes from 0 degree to −45 degrees and becomes 0 degree again, and the flapping flapping shown in FIG. 8 (b) is performed. In the wing launch, feathering is coupled so that the flapping wing pitch angle α goes from 0 degree to 45 degrees and then becomes 0 degree again. At this time, unsteady thrust and lift force are generated when the flapping wing is lowered, and unsteady thrust force and downforce are generated when the flapping wing is launched, according to the fluctuation of the pitch angle α of the flapping wing. The flapping airplane can fly by obtaining a time-averaged thrust of the unsteady thrust generated by the flapping motion and a time-averaged lift of the unsteady lift and downforce.

As a mechanism for realizing such flapping motion, an inclined grooved wheel is fixed to a rotation output shaft, a vibration starting ring that is rotatably fitted to the inclined grooved wheel is further provided, and a flapping blade is integrally formed with the vibration starting ring. Has been invented (see Patent Document 1). In the flapping motion realized by this mechanism, flapping of the flapping wing is coupled with feathering that makes the pitch angle of the flapping wing uniform over the entire width of the flapping wing.
Japanese Patent Publication No.46-12385

  Among the flapping planes, the flapping movement is performed only by the passenger's human power, and the realization of the human flapping plane that uses only the thrust and lift obtained by the flapping movement is an attempt by Leonardo da Vinci. Since then, it has been positioned as a longing for all humankind. However, in spite of numerous attempts to realize a human-powered airplane, flapping by human power has not been realized until the filing date of the present invention.

In order to perform a flapping flight with limited human power, it is necessary to optimize the flapping motion so as to obtain a flapping motion that can efficiently obtain the thrust and lift necessary for the flapping flight. For a conventional flapping airplane having standard performance specifications shown in Table 1, the optimization objective function is the propulsion efficiency η _P shown in Equation 1, and the flapping amplitude φ ₀ shown in FIG. 5 is shown in FIG. The amplitude θ _{0 of} the feathering, the arrangement position a of the feathering shaft made dimensionless by the semi-root code b in the route code c shown in FIG. 6, the phase difference λ between flapping and feathering shown in FIG. It is possible to obtain the aerodynamic analysis performance by the improved unsteady lifting surface theory code optimized by the COMPLEX method so that the suction generated at the leading edge of the flapping wing is taken into consideration with the dimensionless frequency k shown in Fig. 2 as design variables. The optimal flapping motion is disclosed in Table 3.

In the optimal flapping motion in the conventional human-powered flapping airplane shown in Table 3, the propulsion efficiency η _P remains as low as 0.658. According to this propulsion efficiency, for example, in order to fly a human-powered airplane horizontally at 5 m / s, an output of at least 6.7 W is required per 1 kg body weight of the passenger. In addition, in real gas, the propulsion efficiency is further reduced by the influence of viscosity, so the flapping wing pitch angle is uniform over the entire width of the flapping wing in the conventional flapping motion, that is, flapping of the flapping wing. It can be inferred that it is difficult to realize flapping flight by human power because the flapping motion coupled with fluctuating feathering cannot provide the human force with the thrust necessary for the flight of the flapping airplane.

  The present invention has been made in view of the above circumstances, and an object thereof is to realize and provide a human-powered airplane and a human-powered airplane by improving the propulsion efficiency of the human-powered airplane. .

  In addition, the present invention aims to improve the propulsion efficiency of a flapping airplane widely, and intends to improve the performance of a flapping airplane with a motor, particularly a small flying vehicle (MicroAerialVehicle) expected to be used industrially. In flapping airplanes, flapping is used to apply the aerodynamic force and inertial force to the flapping wings and passively elastically deform the flapping wings so that the so-called membrane-type flapping movement is widely used. However, in recent years, it is presumed that there is an increasing tendency to emphasize the cruising distance and flight performance of a flapping airplane, in addition to the ease of realizing the flapping mechanism. Another object of the present invention is to provide an excellent flapping flight method and flapping airplane that realize high propulsion efficiency in a flapping airplane and a small flying vehicle (MicroAerial Vehicle) by pursuing optimization of flapping motion.

  The present invention has the following configuration in order to solve the above problems. That is, the flapping flight method according to the present invention is provided so that the amplitude of feathering of the flapping wing coupled to flapping of the flapping wing increases from the blade root of the flapping wing toward the tip of the flapping wing. It is characterized by that.

  The flapping wing feathering amplitude is set to linearly increase from the flapping wing root toward the flapping wing tip, and the linear increase differential coefficient is 0.085 to 0.115. The position of the feathering axis on the route code of the flapping wing is within the range of 0.3 to 0.7 times the semi-route code length with the midpoint of the route code as a base point. The flapping amplitude is set in the range of 31 to 45 degrees, the phase difference of the feathering with respect to the flapping is set in the range of the advance angle of 76 degrees to the advance angle of 95 degrees, The dimensional frequency is set in the range of 0.2 to 0.28.

  Further, the flapping and the feathering are performed only by human power output from a flapping airplane passenger, and the flapping flight is performed using only the thrust and lift obtained by the flapping and the feathering. Features.

  Further, the flapping airplane according to the present invention is provided such that the amplitude of feathering of the flapping wing coupled to flapping of the flapping wing increases from the blade root of the flapping wing toward the tip of the flapping wing. It is characterized by that.

  The flapping wing feathering amplitude is set to linearly increase from the flapping wing root toward the flapping wing tip, and the linear increase differential coefficient is 0.085 to 0.115. The position of the feathering axis on the route code of the flapping wing is within the range of 0.3 to 0.7 times the semi-route code length with the midpoint of the route code as a base point. The flapping amplitude is set in the range of 31 to 45 degrees, the phase difference of the feathering with respect to the flapping is set in the range of the advance angle of 76 degrees to the advance angle of 95 degrees, The dimensional frequency is set in the range of 0.2 to 0.28.

  In addition, a cylindrical main wing girder having the feathering shaft as a central axis is provided, and a plurality of ribs that slide around an outer peripheral surface of the cylindrical main wing girder and rotate about the feathering shaft are provided. A feathering drive shaft centered on the feathering shaft is fixed to a rib located at the outermost blade edge among a number of ribs, and is provided through the inside of the cylindrical main wing girder, and the feathering drive shaft is twisted Thus, it is provided to perform the feathering.

  Further, the flapping and the feathering are performed only by a human power output by a passenger of the flapping plane, and the flapping flight is performed using only the thrust and the lift obtained by the flapping and the feathering. It is characterized by.

  According to the flapping flight method of the present invention, an excellent flapping flight with a propulsion efficiency of 0.85 or more can be realized. Further, flapping flight by human power can be realized by improving the propulsion efficiency of flapping flight according to the present invention.

  Similarly, according to the present invention, it is possible to realize an excellent flapping airplane having a high propulsion efficiency of 0.85 or higher. Accordingly, it is possible to improve the propulsion efficiency of a flapping aircraft with a motor, particularly a small flying vehicle (MicroAerialVehicle) expected to be used industrially, and it is possible to realize a human-powered flapping aircraft that has not yet been successful.

  Embodiments of the flapping flight method and flapping airplane according to the present invention will be described in detail below. FIG. 1 is an explanatory diagram showing the skeleton of the flapping wing of the flapping airplane according to the present embodiment. In the figure, reference numeral 1 denotes a cylindrical main wing girder provided on a feathering axis of a flapping wing. The main wing girder 1 is fixed to a bearing portion of a main wing girder mounting joint 2, and the main wing girder mounting joint 2 is pivotally supported by a main wing girder mounting pin 4 embedded and fixed to a main wing girder mounting plate 3. As a result, the main wing girder 1 and the main wing girder mounting joint 2 can rotate with the main wing girder mounting pin 4 as a support shaft, and can be flapped.

  Flapping of the flapping wing according to the present embodiment using the main wing girder 1 and the main wing girder attachment joint 2 as its main drive skeleton is performed by a launch wire 15 moored on a wire mooring bush 14 fixed to the center of the wing girder 1 The down wire 16 can be discharged or housed in equal amounts from the up wire guide 17 and the down wire guide 18. In this embodiment, for the purpose of reducing the weight of the drive mechanism, flapping is performed by a wire link mechanism, but of course, as a priority is given to the miniaturization of flapping airplanes, rigid link mechanisms such as cams and cranks are used. The flapping wing may be driven to flapping by using.

  The main wing girder 1, the main wing girder mounting joint 2, the main wing girder mounting plate 3, the main wing girder mounting pin 4, and the wire anchoring bush 14 are preferably formed of a carbon fiber reinforced resin material in order to reduce weight and secure necessary strength. Further, it is desirable that the launch wire 15 and the down wire 16 are formed of Kepler (registered trademark) fibers that are not elastically deformed by a load and do not lose the driving force. Further, in the present embodiment, for the purpose of downsizing the flapping mechanism, the main wing girder mounting pin 2 and the main wing girder mounting pin 4 are provided by setting the shaft diameter of the main wing girder mounting pin 4 to the minimum shaft diameter ensuring the necessary strength. If the sliding resistance needs to be further reduced, a ball bearing is provided on the sliding surface between the main wing girder mounting joint 2 and the main wing girder mounting pin 4. It is desirable.

  Among the ribs provided on the flapping wings 10, 11, and 12 shown in FIG. 1, the rib 12 located at the root of the wing has a fixed mounting angle with respect to the axis of the flapping airplane. It is adhesively fixed on the outer peripheral surface of the main wing girder 1 in a state of being provided. Therefore, in the present embodiment, the rib 12 positioned at the outermost blade root is fixed to the main wing girder 1 and is not driven by feathering. Here, the mounting angle is for giving a predetermined angle of attack to the flapping wing. In the present embodiment, the mounting angle is provided with a mounting angle of +5 degrees. The mounting angle can be arbitrarily set within the range of a normal airplane design method.

  On the other hand, a large number of ribs 10 excluding the ribs 12 located at the outermost blade root and the ribs 11 located at the outermost blade tip are provided in a cylindrical shape in the present embodiment around the feathering axis at every predetermined position. It is provided with a degree of freedom so that it can slide and rotate on the outer peripheral surface of the main wing girder 1 and can feather each. Of course, a ball bearing or other bearing mechanism is interposed between the main wing girder and the rib, so that a large number of ribs 10 and the rib 11 located at the end of the blade can be similarly feathered. Is also possible. If this configuration is applied, the cross-sectional shape of the main wing girder can be any cross-sectional shape. For example, by making the cross-sectional shape of the main wing girder a square shape or an elliptical shape, the main wing accompanying flapping It is also possible to provide a girder so that bending of the girder can be suppressed.

  A plurality of ribs 10, 11, 12 provided on the flapping wings communicate with each other, and a pair of motion guides 13 are arranged with the main wing girder 1 interposed therebetween. The motion guide 13 is a member that imparts torsional rigidity around the feathering axis to the flapping wing. The motion guide 13 penetrates all of the many ribs 10, and both ends thereof are located at the rib 11 located at the end of the wing and the root of the wing. It is fixed to the rib 12 to be provided.

  Next, the feathering drive mechanism in the present embodiment will be described in detail. 1 is a feathering drive shaft provided on the feathering shaft through the inside of the cylindrical main wing girder 1. A universal joint 6 is provided at the blade root portion of the feathering drive shaft 5, and the universal joints 6 of the left and right blades are fitted and held by the main wing girder mounting plate 3 while being coupled and fixed to each other. ing. Among them, the universal joint 6 on the right wing side is integrally provided with a feathering drive lever 8, and the feathering drive lever 8 is connected to a feathering drive link 9. As a result, the left and right feathering drive shafts 5 are completely synchronized with the feathering drive force provided by the same feathering drive link 9 while being folded and flapped by the universal joint 6 provided at the blade root. Then, it rotates around the feathering axis, and the feathering driving force can be transmitted to the left and right flapping wings.

  At the blade tip, the feathering drive shaft 5 is fixed to a rib 11 located at the outermost blade tip with a feathering drive shaft fixing plate 7 interposed. As a result, the rib 11 located at the outermost blade tip is feathered according to the input drive by the feathering drive link 9. Here, the pair of motion guides 13 in the present embodiment is made of an elastic material that allows torsional deformation around the feathering axis. Accordingly, the flapping wing has a rib 12 positioned at the outermost blade root fixed to the main wing girder 1 as a fixed end, and a rib 11 positioned at the outermost blade tip to which the feathering driving force is transmitted, as a rotating end. It is provided in a wing structure that can be elastically twisted and restored around the feathering axis.

  2 and 3 are explanatory views showing the flapping motion of the flapping airplane in the present embodiment. FIG. 2 shows the launching of the flapping wing, and FIG. 3 shows the downing of the flapping wing. As described above, in the launching of the flapping wing in the present embodiment shown in FIG. 2, flapping is performed by storing a fixed amount of the launch wire 15 from the launch wire guide 17 and dropping the equivalent amount of the down wire 16. This is done by discharging from the wire guide 18.

Further, the feathering coupled by the launching of the flapping wing is equivalent to the rib 11 located at the end of the flapping wing 19 and the flapping wing 20 by appropriately controlling the feathering drive link 9 in the direction of pulling down. This is done by giving a pitch angle α _tip of. As a result, in the launching of the flapping wing, feathering in a form in which the flapping wing is twisted up from the root of the flapping wing toward the tip of the wing is coupled.

  Similarly, in the flapping down of the flapping wing in the present embodiment shown in FIG. 3, flapping is performed by dropping the down wire 16 and storing a fixed amount from the wire guide 18, and launching an equal amount of the up wire 15. This is done by discharging from the wire guide 17.

Further, the feathering coupled by the downswing of the flapping wing is equivalent to the rib 11 located at the end of the flapping wing 19 and the flapping wing 20 by appropriately controlling the feathering drive link 9 in the pushing-up direction. This is done by giving a pitch angle of -α _tip . Thereby, in the downstroke of the flapping wing, the feathering in a form in which the flapping wing is twisted down from the root of the flapping wing toward the tip of the wing is coupled.

  Note that the feathering of the flapping wing in the present embodiment is performed against the torsional rigidity around the feathering axis of the motion guide 13 shown in FIG. 1 that is uniformly provided over the entire length thereof. The torsion angle of the flapping wing generated as it goes from the blade root to the blade tip by the feathering drive coincides with the torsion angle of the motion guide 13 around the feathering axis, and as it goes from the blade root to the blade tip. It will increase continuously at a constant rate.

  That is, the amplitude θ of the feathering in the present embodiment is provided so that its magnitude differs in the span direction of the flapping wing, and at a constant ratio from the blade root to the blade tip of the flapping wing. It is provided so that the value increases continuously. In other words, mathematically expressed, when the x-axis shown in FIGS. 2 and 3 is determined on the feathering axis of the flapping wing 19 and the flapping wing 20 in the direction from the blade root to the blade tip, respectively, the feathering Can be explained as being provided so as to increase linearly with a constant differential coefficient dθ / dx.

  As shown in this embodiment, the propulsion efficiency of a flapping airplane can be improved by changing the feathering wing so that the amplitude θ of the feathering increases as it goes from the root to the tip of the wing. The relationship between the configuration and the effect is that the flapping motion is generally a circular motion that draws an arc at the tip of the blade root as a fulcrum, and the speed induced by the flapping motion is proportional to the radius of the flapping motion from the blade root to the tip of the blade. It can be said that it becomes larger as it goes to, and accordingly, the flapping motion can be optimized by increasing the feathering amplitude θ as it goes from the root of the flapping wing to the tip of the wing. Can be described qualitatively.

  In this embodiment, as a result of focusing on the induced speed due to the flapping motion that increases linearly as it goes from the root of the flapping wing to the wing tip, the feathering amplitude θ of the flapping wing It is designed to increase linearly as it goes from the root to the blade tip. Of course, in order to reflect the increase in the induced velocity due to the blade tip vortex, the amplitude of the feathering feathering is reflected. It is also possible to provide θ so that it increases in a higher-order nonlinear manner as it goes from the blade root to the blade tip. In this case, in this embodiment, the torsional rigidity around the feathering axis of the motion guide 13 shown in FIG. 1 that is uniformly provided over the entire length of the flapping wing is directed from the blade root to the blade tip. What is necessary is just to change a structure as what is provided so that it may become small in high-order nonlinearity.

Table 2 discloses the optimal flapping motion according to the present invention. The optimum flapping motion is the flapping amplitude φ ₀ shown in FIG. 5 for the human flapping airplane having the standard performance specifications shown in Table 1 and the optimization objective function is the propulsion efficiency η _P shown in Equation 1. , The differential coefficient dθ / dx of linear increase from the blade root toward the tip of the feathering blade with the amplitude θ of feathering, the arrangement position a of the feathering shaft on the route code shown in FIG. Aerodynamic analysis performance with improved unsteady lifting surface theory code that takes into account the suction generated at the leading edge of the flapping wing, using the phase difference λ between lapping and feathering and the dimensionless frequency k shown in Equation 2 as design variables. Is the optimal flapping motion that can be obtained by optimizing by the COMPLEX method. As shown in Table 2, according to the present invention, a high propulsion efficiency of 0.94 can be obtained in a flapping airplane.

  The flapping motion in the present embodiment is the flapping motion shown in Table 2 as the optimal motion, but in order to meet various specification requirements within the range of ensuring a high efficiency region of 0.85 or more as the propulsion efficiency, A linearly increasing differential coefficient is set in the range of 0.085 to 0.115 as the amplitude of the feathering increases from the blade root to the blade tip of the flapping wing, and the feathering axis on the flapping wing root code is provided. Is arranged at a position in front of the midpoint of the route code in the range of 0.3 to 0.7 times the semi-route code length with the midpoint of the route code as a base point, and the flapping amplitude is set to 31. The phase difference of the feathering with respect to the flapping is set in a range of 76 degrees to 95 degrees, and the dimensionless frequency is 0.2 to 0. It is also possible to carry out off-design as provided in the range of 28. The numerical limitation is based on the optimization numerical calculation described above.

  FIG. 4 is an explanatory view showing an outer skin structure of a flapping wing of a flapping airplane in the present embodiment. The figure shows a state where the flapping wing is twisted down by feathering when the flapping wing is lowered, as viewed from the front edge direction of the wing tip. In the figure, reference numeral 21 denotes a slide rail provided fixed to the outer periphery of the rib. The slide rail 21 is a member that holds the wing surface film 22 at both ends thereof, and the wing surface film 22 is inserted into a sliding groove having an appropriate width so that the wing surface film 22 can freely slide. Is gripped with pressure. For this reason, even when the flapping wing is twisted by feathering, the outer skin structure does not generate torsional rigidity around the feathering axis, so that the outer skin structure contributes to the torsional rigidity of the flapping wing and twists the flapping wing. The angle is not changed, and the feathering driving force of the flapping wing is not lost. The wing surface film 22 is formed of a resin film that can be deformed following the twist of the flapping wing, and when the flapping wing is twisted, the rib and the adjacent rib are interpolated by a curved surface. Thus, a continuous blade surface can be formed.

  Here, in the present embodiment, since the flapping wing is tapered, the wing leading edge portion of the wing surface film 22 is large when the flapping wing is twisted only by using the structure described above. A habit will occur. This is due to the fact that the curvature of the blade surface film 22 is maximized at the blade leading edge, and that the shape of the adjacent ribs differs depending on the taper provided on the flapping wing. Therefore, in the present embodiment, the blade surface film 22 is eliminated at the blade leading edge portion, and instead of this, the leading edge block 23 is provided to constitute a flapping wing. Specifically, the blade surface film 22 provided separately on the upper and lower surfaces of the flapping wing is fixed to the leading edge block 23 to form the wing surface, and the side surface portion of the leading edge block 23 is formed in a hemispherical shape. By being formed, the leading edge block 23 and the rib that abuts against the front edge block 23 are provided so as to abut by point contact. With this configuration, even when twisting the flapping wing provided with the taper, the leading edge of the wing does not wrinkle, and the leading edge block 23 and the rib abutting against the leading edge block 23 are prevented. Since the contact state can be changed flexibly, the blade surface can be formed by suitably following the twist of the flapping wing.

  As mentioned above, although the individual specific form was shown and explained in detail about embodiment of the flapping flight method and flapping airplane concerning the present invention, exemplary embodiment presented here leads to suitable implementation about the present invention. Therefore, the technical scope of the embodiments of the present invention is not defined, and the embodiments according to the present invention cover all the embodiments based on the present invention. .

It is explanatory drawing which showed the skeleton of the flapping wing of the flapping airplane by this invention. It is explanatory drawing which showed the flapping movement of the flapping airplane by this invention. It is explanatory drawing which showed the flapping movement of the flapping airplane by this invention. It is explanatory drawing which showed the skin structure of the flapping wing of the flapping airplane by this invention. It is explanatory drawing which showed the flapping movement of the flapping airplane. It is explanatory drawing which showed the flapping movement of the flapping airplane. It is explanatory drawing which showed the flapping movement of the flapping airplane. It is explanatory drawing which showed the flapping movement of the flapping airplane.

Explanation of symbols

1 Main Wing Girder 2 Main Wing Girder Mounting Joint 3 Main Wing Girder Mounting Plate 4 Main Wing Girder Mounting Pin 5 Feathering Drive Shaft 6 Universal Joint 7 Feathering Drive Shaft Fixing Plate 8 Feathering Drive Lever 9 Feathering Drive Link 10 Rib 11 Positioned rib 12 Positioned rib at the root of the blade 13 Motion guide 14 Wire anchoring bush 15 Launch wire 16 Down wire 17 Launch wire guide 18 Down wire guide 19 Flapping wing (left)
20 Flapping wing (right)
21 Slide rail 22 Wing surface film 23 Leading edge block

Claims (4)

A flapping airplane characterized in that the flapping wing feathering amplitude coupled with flapping wing flapping increases from the flapping wing root toward the flapping wing tip. The flapping wing feathering amplitude is provided so as to increase linearly from the flapping wing root toward the flapping wing tip, and the differential coefficient of the linear increase is in the range of 0.085 to 0.115. The position of the feathering shaft on the flapping wing route code is within the range of 0.3 to 0.7 times the semi-root cord length from the midpoint of the route code as a base point, and from the midpoint of the route code Provided in a forward position, the flapping amplitude is set in a range of 31 to 45 degrees, the phase difference of the feathering with respect to the flapping is set in a range of an advance angle of 76 degrees to an advance angle of 95 degrees, and dimensionless vibration The flapping airplane according to claim 1, wherein the number is set in a range of 0.2 to 0.28. A cylindrical main wing girder having the feathering shaft as a central axis is provided, and a plurality of ribs that slide around the outer peripheral surface of the cylindrical main wing girder and rotate about the feathering shaft are provided. A feathering drive shaft with the feathering shaft as a central axis fixed to a rib located at the outermost blade end of the ribs is provided through the inside of the cylindrical main wing girder, and the feathering drive shaft is twisted. The flapping airplane according to claim 2, which is provided so as to perform the feathering. The flapping and the feathering are performed only by a human power output by a passenger of the flapping airplane, and the flapping flight is performed using only the thrust and the lift obtained by the flapping and the feathering. The flapping airplane according to any one of claims 1 to 3.

Images