AERIAL VEHICLE

Abstract

The invention is directed to an aerial vehicle with a hybrid drive unit (10) and with a rotor unit (1, 1′) wherein the hybrid drive unit (10) comprises at least a combustion engine (11), a generator (12) and a first electric motor (7) and the rotor unit (1, 1′) comprises a first rotor (1), wherein the combustion engine (11) is configured to drive the generator (12) to produce electricity, the generator (12) is coupled to the first electric motor (7) in such a way that the first electric motor (7) is feedable with electricity from the generator (12). The rotor unit (1, 1′) comprises a second rotor (1) and the hybrid drive unit (10) comprises a second electric motor (7′), wherein the generator (12) is coupled to the second electric motor (7′) in such a way that the second electric motor (7′) is feedable with electricity from the generator (12), and wherein the first rotor (1) is driven by the first electric motor (7) and the second rotor (1′) is driven by the second electric motor (7′).

Claims

1. An aerial vehicle comprising: a hybrid drive unit; and a rotor unit, wherein the hybrid drive unit comprises a combustion engine, a generator a first electric motor, and a second electric motor, wherein the rotor unit comprises a first rotor, and a second rotor, wherein the combustion engine is configured to drive the generator to produce electricity, wherein the generator is coupled to the first electric motor such that the first electric motor is feedable with electricity from the generator, wherein the generator is coupled to the second electric motor such that the second electric motor is feedable with electricity from the generator, wherein the first electric motor is coupled to the first rotor to drive the first rotor, and wherein the second electric motor is coupled to the second rotor to drive the second rotor.

2. The aerial vehicle according to claim 1, wherein the hybrid drive unit further comprises at least one buffer battery which is coupled to the generator to be fed with electricity produced by the generator, and to the first electric motor and/or the second electric motor to feed the first electric motor and/or the second electric motor.

3. The aerial vehicle according to claim 1, wherein a shaft of the first rotor and a shaft of the second rotor are coupled to one another by means of a coupling unit.

4. The aerial vehicle according to claim 3, wherein the coupling unit is a gear unit comprising a first synchro gear wheel being coupled to the shaft of the first rotor and a second synchro gear wheel being coupled to the shaft of the second rotor.

5. The aerial vehicle according to claim 4, wherein the first synchro gear wheel and the second synchro gear wheel engage.

6. The aerial vehicle according to claim 1, wherein the first rotor and the second rotor are configured to rotate in opposite directions and to mesh in an interleaved manner.

7. The aerial vehicle according to claim 1, wherein the first rotor and the second rotor are configured to rotate at an angular offset of 90°.

8. The aerial vehicle according to claim 1, wherein the first rotor and the second rotor are inclined with regard to a horizontal axis of the rotor unit in opposite directions.

9. The aerial vehicle according to claim 8, wherein an inclination of the rotor blades with regard to the horizontal axis is between 5° and 20°, preferably between 10° and 15°.

10. The aerial vehicle according to claim 1, wherein at least at one of the two rotors a sensor is provided for measuring a rotor speed.

11. The aerial vehicle according to claim 1, wherein the rotor unit comprises upper, rotating swash plates and lower, non-rotating swash plates.

12. The aerial vehicle according to claim 11, wherein at least one servo drive is arranged at the lower, non-rotating swash-plate.

13. The aerial vehicle according to claim 1, wherein the hybrid drive unit is formed as serial hybrid drive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Additional advantageous configurations of the invention arise from the subsequent description of the embodiments of the invention with the aid of the schematic drawings. In particular, the fastening element according to the invention is subsequently described in detail with reference to the included drawings with the aid of the embodiments. It shows:

[0026] FIG. 1: a drive scheme for an aerial vehicle according to the prior art;

[0027] FIG. 2: a drive scheme for the inventive aerial vehicle;

[0028] FIG. 3: a schematic representation of the inventive serial hybrid drive unit; and

[0029] FIG. 4: a schematic representation of the inventive rotor unit with the two rotors being coupled to one another via a gear unit.

WAY(S) TO IMPLEMENT THE INVENTION

[0030] Certain expressions are used in the following description for practical reasons and are not to be understood as limiting. The words “right”, “left”, “below”, and “above” indicate directions in the drawing which is being referenced. The expressions “inwardly”, “outwardly”, “beneath”, “above”, “to the left of”, “to the right of”, or the like are used to describe the arrangement of designated parts relative to one another, the movement of designated parts relative to one another, and the directions toward or away from the geometric center of the invention and the listed parts of the same as shown in the figures. These relative spatial directions also comprise other positions and directions than those shown in the figures. For example, if a part shown in the figures is rotated, then elements or features that were described as “below” are then “above”. The terminology comprises the above, explicitly mentioned words, derivations of the same, and words of similar meaning.

[0031] In order to avoid repetitions in the figures and the associated description of the different aspects and embodiments, certain features are to be understood as common for different aspects and embodiments. The omission of one aspect in the description or in a figure does not allow for the conclusion that this aspect is lacking in the associated embodiment. Rather, such an omission may increase clarity and prevent repetitions. In this context, the following definition applies for the entire subsequent description: If reference numerals are contained in one figure for the purpose of graphic clarity; however, not mentioned in the directly associated textual description, then reference is made to the detailed explanation thereof in the preceding descriptions of the figures. If, in addition, reference numerals are mentioned in the textual description directly associated with a figure, which reference numerals are not included in the associated figure, then reference is made to the preceding and following figures. Similar reference numerals in two or more figures indicate similar or identical elements.

[0032] FIG. 1 schematically depicts a drive unit of a prior art UAV. Here, the turbine drives a gear unit which comprises eight gear wheels altogether and which may provide for a mechanical transmission from 100,000 rpm to 950 rpm. The turbine has an endurance of 2 hours with a consumption of about 15 l/h. Due to the relatively high mechanical complexity, the drive unit comprises several single points of failure.

[0033] Contrary to this, the inventive drive unit illustrated schematically in FIG. 2 only requires two synchro gear wheels which are just used in case one of the two electric motors fails and to keep the two rotors synchronized. The drive unit includes an electrical transmission from motor rpm to rotor rpm. The combustion engine which drives the generator may be a piston engine or a rotary engine. The drive unit further comprises a buffer battery which is charged with electricity from the generator. The buffer battery, which is also connected to the engine control unit (ECU), is designed such that in case of a motor failure a safe landing of the aerial vehicle is always guaranteed. More specifically, the remaining flight time should be approximately 15 to 20 minutes, i.e. sufficiently long to safely land the aerial vehicle even if the latter is further remote from the starting point and/or in a high risk environment. Due to the reduced mechanical complexity, the inventive drive unit comprises less single point of failures.

[0034] In FIG. 3 the power generation of the serial hybrid drive unit 10 in accordance with the present invention is shown. The combustion engine 11 operates with fuel and air and comprises an engine control unit (ECU). The combustion engine 11 drives a generator 12 which produces electricity and which is connected to a serial hybrid ECU. The serial hybrid ECU includes power electronics and control electronics. The power electronics controls the required electricity for the electric motors 7, 7′ at the rotor shafts as well as for the buffer battery. The power electronics is further connected to an auxiliary control power. The control electronics receives rpm sensor signals from the rotor shafts and flight control inputs and provides for a respective telemetry output.

[0035] FIG. 4 shows the inventive rotor unit which comprises first rotor 1 and second rotor 1′. Each rotor 1, 1′ comprises a rotor shaft 8, 8′ and a rotor head 2, 2′ to which two rotor blades 3, 3′ are coupled, respectively. Rotor blades 3, 3′ are connected to an upper, rotating swash plate 4, 4′. A lower, non-rotating swash plate 5, 5′ is connected to the upper, rotating swash plate 4, 4′. The two swash plates form a swash plate unit 4, 4′; 5, 5′. At the underside of the lower, non-rotating swash plate 5, 5′ four servo drives 6, 6′ are arranged which shall provide for a tilting of the swash plate unit 4, 4′; 5, 5′ in all directions and moving the swash plate unit up and down. Tilting the swash plate unit 4, 4′; 5, 5′ enables a cyclical change in the setting angle; raising and lowering the swash plate unit changes the angle of attack of all rotor blades 3, 3′ in the same way and thus leads to a collective change in the angle of attack.

[0036] Electric motors 7, 7′ are provided for driving the rotor shafts 8, 8′. In this embodiment, the right rotor 1′ is equipped with a sensor S for measuring the rotor speed. Sensor S generates a respective rpm sensor signal for the control electronics of the serial hybrid ECU (cf. also FIG. 3). The serial hybrid ECU controls the electricity required by electric motors 7, 7′ and the buffer battery 13. Each rotor shaft 8, 8′ is coupled at its lower end to a synchro gear wheel 9, 9′. The two synchro gear 9, 9′ wheels act together as a gear unit as coupling unit.

[0037] The first rotor 1 and the second rotor 1′ are inclined in opposite directions with regard to a horizontal axis X of the rotor unit. Specifically, the inclination I of the rotor blades 3, 3′ with regard to the horizontal axis X is between 5° and 20°, preferably between 10° and 15°. Further, the first rotor 1 and the second rotor 1′ are configured to rotate in opposite directions and to mesh (i.e. with their rotor blades 3, 3′) in an interleaved manner. Thereby, the first rotor 1 and the second rotor 2 are preferably operated with an angular offset of 90°. The inventive rotor unit 1, 1′ is a so-called Flettner-type double rotor unit.

[0038] It will be appreciated that the present invention advantageously combines a serial hybrid concept to a Flettner-type helicopter, manned or unmanned and independent of its size, since the benefits of the present invention apply for any size, if additional overall system reliability is desired. The invention adds redundancy to the entire drive train by reducing mechanical complexity at the same time.

[0039] Even though the invention is depicted and described in detail by means of the figures and the associated description, this depiction and this detailed description are to be understood as illustrative and exemplary, and not as limiting the invention. In order to not transfigure the invention, in certain cases, well-known structures and technologies may not be shown and described in detail. It is understood that persons skilled in the art may make changes and modifications without abandoning the scope of the following claims. In particular, the present invention covers additional embodiments having any combination of features that may deviate from the explicitly described combination of features.

[0040] The present disclosure also comprises embodiments with any combination of feature that are listed or shown previously or subsequently to the embodiments. It likewise comprises individual features in the figures, even if they are shown there in conjunction with other features and/or are not listed previously or subsequently. The alternatives described in the figures may be excluded from embodiments and the description and individual alternatives, whose features may be excluded from the subject matter of the invention or from the disclosed subject matter. The disclosure comprises embodiments that exclusively comprise the features described in the claims or in the embodiments, as well as those that comprise additional other features.

[0041] Furthermore, the expression “comprises” and deviations thereof do not exclude other elements or steps. Likewise, the indefinite article “a” or “an” and deviations thereof does not exclude a plurality. The functions of many features explained in the claims may be satisfied by a unit or a step. The terms “essentially”, “approximately”, “roughly”, “virtually” and the like, in combination with a property or a value, define in particular the property exactly or the value exactly. The terms “approximately” and “roughly” in conjunction with a given numeric value or range may relate to a value or range which is positioned within 20%, within 10%, within 5% or within 2% of the given value or range.

LIST OF REFERENCE NUMBERS

[0042] 1, 1′ rotors [0043] 2, 2′ rotor heads [0044] 3, 3′ rotor blades [0045] 4, 4′ upper swash plates [0046] 5, 5′ lower swash plates [0047] 6, 6′ servo drives [0048] 7, 7′ electric motors [0049] 8, 8′ rotor shafts [0050] 9, 9′ synchro gear wheels [0051] 10 hybrid drive unit [0052] 11 combustion engine [0053] 12 generator [0054] 13 buffer battery [0055] I inclination [0056] S sensor [0057] X horizontal axis