CN109774917B - Miniature double-rotor aircraft - Google Patents
Miniature double-rotor aircraft Download PDFInfo
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- CN109774917B CN109774917B CN201910093517.2A CN201910093517A CN109774917B CN 109774917 B CN109774917 B CN 109774917B CN 201910093517 A CN201910093517 A CN 201910093517A CN 109774917 B CN109774917 B CN 109774917B
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- 239000000919 ceramic Substances 0.000 claims description 7
- 239000011159 matrix material Substances 0.000 claims description 4
- 230000009977 dual effect Effects 0.000 claims description 2
- 238000006073 displacement reaction Methods 0.000 description 4
- 230000007246 mechanism Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000010146 3D printing Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
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- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Abstract
The invention discloses a miniature double-rotor aircraft, which belongs to the field of piezoelectric actuators and utilizes a piezoelectric bimorph as a posture adjustment driving device to realize further miniaturization and light weight of the miniature aircraft in posture adjustment. According to the invention, lift force is provided by a pair of reversely installed propellers and a hollow cup motor, reverse torque is overcome, three bimorphs are simply supported and installed on a lower base through a rotating shaft, pre-pressure is applied to the bimorphs through an elastic element, the bimorphs are buckled and installed in the middle of the bimorphs, the bimorphs are connected with an upper base through three push pull rings, and the upper base is connected with the lower base through a ball bearing structure. The invention utilizes the maximum deflection (middle deflection) of the axially precompressed simply supported bimorph to push and pull the upper base, thereby driving the upper rotor wing and the lower rotor wing to generate an included angle to realize the adjustment of any gesture.
Description
Technical Field
The invention belongs to the field of piezoelectric actuators, and particularly relates to a miniature double-rotor aircraft.
Background
The small double-rotor aircraft has the capabilities of vertical take-off and landing, hovering in the air, flying back and forth and left and right, can realize fixed-point landing, does not need a special airport, can be applied to various tasks, and has wide application in military and civil aspects such as deep forest fire prevention, traffic monitoring, farmland protection, aerial photography and aerial survey. The coaxial double-rotor unmanned aerial vehicle without tail rotor developed by Beijing aviation aerospace university on the basis of seagull has a control mechanism which is as same as a helicopter and has a spherical engine body, the control mechanism of the coaxial double-rotor unmanned aerial vehicle is complex, and the spherical engine body reduces the flexibility of the aerial vehicle (Chen Ming, hu Jizhong.M22, the design characteristics of a small unmanned helicopter [ J ] aircraft design, 2005, (01): 71-74.). Compared with other types of aircrafts, the existing small-sized double-rotor aircraft has the defects of fewer types, relatively low maturity, insufficient maturity of structural design and attitude control technology and narrow application range.
Disclosure of Invention
The invention provides a miniature double-rotor aircraft, which uses a piezoelectric bimorph as a gesture adjustment driving device, so that the miniature aircraft is further miniaturized and light in gesture adjustment.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a miniature dual rotor aircraft comprising: a base portion, a flight portion, and an attitude adjustment portion; the base part comprises a lower base 6 and an upper base 7, the lower base 6 and the upper base 7 are connected through corresponding ball bearings 61 and 72 on the two bases, the lower base 6 comprises a lower base ball bearing 61, three lower base flexible beams 62 and six lower base support frames 64, the lower base ball bearing 61 is positioned at the top center of the lower base 6, the three lower base flexible beams 62 are respectively positioned on the side surfaces of the lower base 6 and form equal angles, the middle part of the lower base flexible beams 62 is branched to the tail end, grooves 65 are respectively arranged at the branching position of the tail end of the lower base flexible beams 62, the six lower base support frames 64 are respectively positioned at the branching position of the middle part of the lower base flexible beams 62 in pairs, and two sides of each lower base support frame 64 are respectively provided with a rotating shaft mounting hole 63; the upper base 7 comprises three upper base bosses 71 and an upper base ball bearing 72, the upper base ball bearing 72 is positioned at the bottom center of the upper base 7, and the three upper base bosses 71 are respectively positioned on the side surfaces of the upper base 7 and form the same angle between every two upper base bosses;
the flying part comprises a motor 9 and a propeller 1, wherein the motor 9 is provided with two motor mounting holes 66 which are respectively arranged at the bottom of the lower base 6 and motor mounting holes 73 which are respectively arranged at the top of the upper base 7, and the propeller 1 is provided with two groups which are respectively arranged on output shafts 10 of the two motors 9 and are opposite in rotation direction;
the posture adjusting part comprises a rotating shaft 2, a buckle 3, a push-pull ring 4, a piezoelectric bimorph 5 and an elastic element 8; six rotating shafts 2 are respectively arranged on the lower base support frame 64 through rotating shaft mounting holes 63; the number of the piezoelectric bimorphs 5 is three, and two sides of each piezoelectric bimorph 5 are respectively arranged in the clamping grooves in the middle of the two rotating shafts 2; three buckles 3 are arranged, and each buckle 3 is respectively arranged in the middle of the piezoelectric bimorph 5; the number of the push-pull rings 4 is three, one end of each push-pull ring 4 is arranged in the mounting hole on the inner side of the buckle 3, and the other end is arranged in the mounting hole of the upper base boss 71; the number of the elastic elements 8 is three, and two ends of each elastic element 8 are respectively arranged in grooves 65 at the tail ends of the lower base flexible beams 62.
In the above-described structure, the piezoelectric bimorph 5 is composed of the piezoelectric ceramic layer 51 and the base layer 52, the piezoelectric ceramic layer 51 is two layers, and the base layer 52 is located in the middle of the two piezoelectric ceramic layers 51; the output shafts 10 of the two motors 9 rotate in opposite directions.
The invention has the beneficial effects that: the invention provides a miniature double-rotor aircraft, which uses piezoelectric bimorphs as actuating mechanisms for adjusting the posture of the miniature aircraft, so that the whole aircraft is smaller in size and lighter in weight, the bimorphs can be designed according to relevant parameters of the aircraft, the aircraft is further miniaturized, the whole aircraft can be manufactured by adopting a 3D printing process, and the whole aircraft quality can be controlled within 30 g; the piezoelectric material has the characteristic of quick response, and the bimorph made of the piezoelectric material is applied to the actuating mechanism for adjusting the posture of the micro aircraft, so that millisecond-level response can be realized, and the controllability of the whole aircraft in the flight process is enhanced; according to the invention, three bimorphs are adopted, the upper base is changed in any position through the three push-pull rings, and locking is realized after the upper base is in place under the synergistic effect of the three bimorphs, so that the attitude angle can be changed in any direction, namely, the flight track of the aircraft can be carried out in any direction at any time. The aircraft of the invention is insensitive to magnetic fields and does not generate magnetic fields; the speed and position control performance is good, and the precision is high; the control bandwidth is high; the power consumption is relatively small; the appearance can be designed arbitrarily according to the requirements of users; vibration, small noise and stable operation.
Drawings
Fig. 1 is a schematic view of a piezoelectric bimorph structure.
Figure 2 is a schematic diagram of the force and displacement output patterns of an axially precompressed simply supported bimorph.
Fig. 3 is a schematic structural view of the present invention.
Fig. 4 is a view showing the external structure of the lower base of the present invention.
Fig. 5 is a half cross-sectional view of the lower base of the present invention.
Fig. 6 is an external structural view of the upper base of the present invention.
Fig. 7 is a half cross-sectional view of the upper base of the present invention.
Fig. 8 is a schematic diagram of the manner in which the axially precompressed simple twin wafers of the present invention are precompressed.
In the figure, 1 is a propeller, 2 is a rotating shaft, 3 is a buckle, 4 is a push-pull ring, 5 is a piezoelectric bimorph, 6 is a lower base, 7 is an upper base, 8 is an elastic element, 9 is a motor, 10 is a motor output shaft, 51 is a piezoelectric ceramic layer, 52 is a matrix layer, 61 is a lower base ball bearing, 62 is a lower base flexible beam, 63 is a rotating shaft mounting hole, 64 is a lower base support frame, 65 is a lower base flexible beam groove, 66 is a lower base motor mounting hole, 71 is an upper base boss, 72 is an upper base ball bearing, and 73 is an upper base motor mounting hole.
Detailed Description
The invention is described in detail below with reference to the attached drawings and the specific embodiments:
as shown in fig. 3, a miniature dual-rotor aircraft, comprising: a base portion, a flight portion, and an attitude adjustment portion; the base part comprises a lower base 6 and an upper base 7, the lower base 6 and the upper base 7 are connected through corresponding ball bearings 61 and 72 on the two bases, as shown in fig. 4 and 5, the lower base 6 comprises a lower base ball bearing 61, three lower base flexible beams 62 and six lower base support frames 64, the lower base ball bearing 61 is positioned at the top center position of the lower base 6, the three lower base flexible beams 62 are respectively positioned at the side surfaces of the lower base 6, the angles formed by the two lower base flexible beams 62 are equal, the middle part of the lower base flexible beams 62 is branched to the tail end, grooves 65 are respectively arranged at the branching position of the tail end of the lower base flexible beams 62, two groups of the six lower base support frames 64 are respectively positioned at the branching position of the middle part of the lower base flexible beams 62, and two sides of each lower base support frame 64 are respectively provided with a rotating shaft mounting hole 63; as shown in fig. 6 and 7, the upper base 7 includes three upper base bosses 71 and an upper base ball bearing 72, the upper base ball bearing 72 is located at the bottom center of the upper base 7, and the three upper base bosses 71 are located at the side surfaces of the upper base 7, respectively, and form the same angle between each two.
The flying part comprises a motor 9 and a propeller 1, wherein the motor 9 is provided with two motor mounting holes 66 which are respectively arranged at the bottom of the lower base 6 and motor mounting holes 73 which are arranged at the top of the upper base 7, the rotation directions of output shafts 10 of the two motors 9 are opposite to counteract the reverse torque born by the base, and a pair of reverse propellers 1 are respectively arranged on the output shafts of a pair of hollow cup motors 9 to provide upward lifting force together. The propellers 1 are two groups, are respectively arranged on output shafts 10 of the two motors 9 and are opposite in rotation direction, and the reverse propellers 1 and the motors 9 together provide upward lifting force.
The posture adjusting part comprises a rotating shaft 2, a buckle 3, a push-pull ring 4, a piezoelectric bimorph 5 and an elastic element 8; six rotating shafts 2 are respectively arranged on the lower base support frame 64 through rotating shaft mounting holes 63; the number of the piezoelectric bimorphs 5 is three, and two sides of each piezoelectric bimorph 5 are respectively arranged in clamping grooves in the middle of two rotating shafts 2; three buckles 3 are arranged, and each buckle 3 is respectively arranged in the middle of the piezoelectric bimorph 5; the number of the push-pull rings 4 is three, one end of each push-pull ring 4 is arranged in the mounting hole on the inner side of the buckle 3, and the other end is arranged in the mounting hole of the upper base boss 71; the number of the elastic elements 8 is three, and two ends of each elastic element 8 are respectively arranged in the grooves 65 at the tail ends of the lower base flexible beams 62; the three bimorphs 5 are simply supported and mounted on the lower base 6 through the rotating shaft 2, and pre-stress is applied to the bimorphs 5 through the elastic element 8, so that the force and displacement output capacity of the bimorphs are improved, as shown in fig. 1, the piezoelectric bimorphs 5 are composed of an upper layer of piezoceramics 51, a lower layer of piezoceramics 51 and a middle matrix layer 52, when one end of each piezoelectric bimorph 5 is hinged, the other end of each piezoelectric bimorph is supported in a sliding manner, and when axial pre-stress is applied to the sliding end, the deformation mode of the middle bulge shown in fig. 2 is generated, and the output displacement reaches the maximum in the middle, and due to the application of the pre-stress, the electromechanical conversion efficiency of the piezoelectric bimorphs 5 is improved, and therefore the output force and the output displacement can be further amplified.
The buckle 3 is arranged in the middle of the double-crystal plate 5 and is connected with the upper base 7 through three push-pull rings 4; the upper base 7 is connected with the lower base 6 through a ball bearing structure, and the upper base 7 is pushed and pulled by utilizing the maximum deflection (middle deflection) of the axial precompressed simply supported bimorph under the action of the three push-pull rings 4, so that an included angle between the upper rotor wing and the lower rotor wing is driven to realize the adjustment of the gesture, and the adjustment of any angle gesture of the aircraft is realized.
The foregoing is merely a preferred embodiment of the present invention and will assist those skilled in the art in further understanding the present invention, but is not intended to limit the present invention in any way. It should be noted that several variations and modifications could be made by those skilled in the art without departing from the spirit of the invention, which would fall within the scope of the invention.
Claims (1)
1. A miniature dual rotor aircraft, comprising: a base portion, a flight portion, and an attitude adjustment portion; the base part comprises a lower base (6) and an upper base (7), the lower base (6) and the upper base (7) are connected with an upper base ball bearing (72) through corresponding lower base ball bearings (61) on the two bases, the lower base (6) comprises a lower base ball bearing (61), three lower base flexible beams (62) and six lower base support frames (64), the lower base ball bearing (61) is positioned at the top center position of the lower base (6), the three lower base flexible beams (62) are respectively positioned at the side surfaces of the lower base (6) and have equal angles formed between every two of the lower base flexible beams, the middle part of the lower base flexible beams (62) is branched to the tail end, grooves (65) are respectively arranged at the branching positions of the tail ends of the lower base flexible beams (62), two groups of six lower base support frames (64) are respectively positioned at the branching positions of the middle parts of the lower base flexible beams (62), and two sides of each lower base support frame (64) are respectively provided with a rotating shaft mounting hole (63); the upper base (7) comprises three upper base bosses (71) and an upper base ball bearing (72), the upper base ball bearing (72) is positioned at the bottom center of the upper base (7), and the three upper base bosses (71) are respectively positioned on the side surfaces of the upper base (7) and form the same angle between every two upper base bosses;
the flying part comprises a motor (9) and a propeller (1), wherein the motor (9) is provided with two lower base motor mounting holes (66) which are respectively arranged at the bottom of the lower base (6) and an upper base motor mounting hole (73) which is arranged at the top of the upper base (7), and the propellers (1) are in two groups, are respectively arranged on output shafts (10) of the two motors (9) and are opposite in rotation direction; the rotation directions of the output shafts (10) of the two motors (9) are opposite;
the gesture adjusting part comprises a rotating shaft (2), a buckle (3), a push pull ring (4), a piezoelectric bimorph (5) and an elastic element (8); six rotating shafts (2) are respectively arranged on the lower base support frame (64) through rotating shaft mounting holes (63); the number of the piezoelectric bimorphs (5) is three, and two sides of each piezoelectric bimorph (5) are respectively arranged in clamping grooves in the middle of the two rotating shafts (2); three buckles (3) are arranged, and each buckle (3) is respectively arranged in the middle of the piezoelectric bimorph (5); the number of the push-pull rings (4) is three, one end of each push-pull ring (4) is arranged in the mounting hole at the inner side of the buckle (3), and the other end is arranged in the mounting hole of the boss (71) of the upper base; the number of the elastic elements (8) is three, and two ends of each elastic element (8) are respectively arranged in grooves (65) at the tail ends of the lower base flexible beams (62); the piezoelectric bimorph (5) is composed of a piezoelectric ceramic layer (51) and a matrix layer (52), wherein the piezoelectric ceramic layer (51) is two layers, and the matrix layer (52) is positioned in the middle of the two piezoelectric ceramic layers (51).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910093517.2A CN109774917B (en) | 2019-01-30 | 2019-01-30 | Miniature double-rotor aircraft |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910093517.2A CN109774917B (en) | 2019-01-30 | 2019-01-30 | Miniature double-rotor aircraft |
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| CN109774917A CN109774917A (en) | 2019-05-21 |
| CN109774917B true CN109774917B (en) | 2024-04-16 |
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| CN201910093517.2A Active CN109774917B (en) | 2019-01-30 | 2019-01-30 | Miniature double-rotor aircraft |
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3637322A (en) * | 1969-02-26 | 1972-01-25 | Dornier Ag | Rotor head for a helicopter |
| RU2156208C1 (en) * | 1999-04-14 | 2000-09-20 | Любимов Александр Александрович | Helicopter column |
| CN201394364Y (en) * | 2009-04-14 | 2010-02-03 | 深圳市艾特航模股份有限公司 | Model and toy helicopter rotor control system |
| CN102390530A (en) * | 2011-09-19 | 2012-03-28 | 北京航空航天大学 | Micromechanical controllable flapping rotary wing aircraft and manufacturing method as well as control method thereof |
| CN105253300A (en) * | 2015-11-08 | 2016-01-20 | 北京航空航天大学 | Minitype co-shaft double-rotor wing unmanned aerial vehicle based on oscillation damping rotor wing |
| CN106915457A (en) * | 2017-02-22 | 2017-07-04 | 北京航空航天大学 | A kind of variable co-axial helicopter steerable system of upper and lower rotor inclinator depth of parallelism |
| CN107352026A (en) * | 2017-08-30 | 2017-11-17 | 威海星煜无人机科技有限公司 | A kind of coaxial unmanned plane for reversely rotating double-output transmission device and using the device |
| CN207759012U (en) * | 2018-01-17 | 2018-08-24 | 重庆大学 | DCB Specimen is taken photo by plane unmanned plane |
| CN108557070A (en) * | 2018-04-12 | 2018-09-21 | 北京理工大学 | A kind of small-sized coaxial dual-rotor helicopter |
| CN209814264U (en) * | 2019-01-30 | 2019-12-20 | 南京航空航天大学 | Miniature dual-rotor aircraft |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2397113C2 (en) * | 2005-10-05 | 2010-08-20 | Сикорски Эркрафт Корпорейшн | Mechanism of parrying swash plate torque |
| US8464978B2 (en) * | 2009-04-16 | 2013-06-18 | The Trustees Of The University Of Pennsylvania | Counter-rotational inertial control of rotorcraft |
-
2019
- 2019-01-30 CN CN201910093517.2A patent/CN109774917B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3637322A (en) * | 1969-02-26 | 1972-01-25 | Dornier Ag | Rotor head for a helicopter |
| RU2156208C1 (en) * | 1999-04-14 | 2000-09-20 | Любимов Александр Александрович | Helicopter column |
| CN201394364Y (en) * | 2009-04-14 | 2010-02-03 | 深圳市艾特航模股份有限公司 | Model and toy helicopter rotor control system |
| CN102390530A (en) * | 2011-09-19 | 2012-03-28 | 北京航空航天大学 | Micromechanical controllable flapping rotary wing aircraft and manufacturing method as well as control method thereof |
| CN105253300A (en) * | 2015-11-08 | 2016-01-20 | 北京航空航天大学 | Minitype co-shaft double-rotor wing unmanned aerial vehicle based on oscillation damping rotor wing |
| CN106915457A (en) * | 2017-02-22 | 2017-07-04 | 北京航空航天大学 | A kind of variable co-axial helicopter steerable system of upper and lower rotor inclinator depth of parallelism |
| CN107352026A (en) * | 2017-08-30 | 2017-11-17 | 威海星煜无人机科技有限公司 | A kind of coaxial unmanned plane for reversely rotating double-output transmission device and using the device |
| CN207759012U (en) * | 2018-01-17 | 2018-08-24 | 重庆大学 | DCB Specimen is taken photo by plane unmanned plane |
| CN108557070A (en) * | 2018-04-12 | 2018-09-21 | 北京理工大学 | A kind of small-sized coaxial dual-rotor helicopter |
| CN209814264U (en) * | 2019-01-30 | 2019-12-20 | 南京航空航天大学 | Miniature dual-rotor aircraft |
Non-Patent Citations (1)
| Title |
|---|
| 用于微型飞行器的高转速超声电机;王乐;王永杰;芦小龙;赵淳生;;振动.测试与诊断;20180215(第01期);170-175 * |
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| CN109774917A (en) | 2019-05-21 |
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