Device for measuring rotational speed of propeller of aircraft

Abstract

Device (210) for measuring the rotational speed of a propeller (211) of an aircraft, comprising:-an optical speed sensor (220); -an optical fiber (230) connected to the optical speed sensor and intended to be connected to an aircraft control unit; and-at least one target (251, 252) configured to follow rotation of the propeller, the optical speed sensor configured to detect these targets.

Description

Technical Field

[0001] The present invention relates to the general field of phase synchronization between aircraft propellers and, more particularly, to measuring the rotational speed of these propellers to allow such synchronization. Background Art

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. In fact, states have, are or will adopt various carbon emission restrictions. Specifically, an ambitious standard is being applied to both new aircraft and those currently in circulation, requiring the implementation of technical solutions to bring them into compliance with the current regulations. For several years now, civil aviation has been mobilizing to contribute to the fight against climate change.

[0003] Technological research has significantly improved the performance of environmentally friendly aircraft. Applicants are considering factors that influence all stages of design and development in order to obtain aeronautical artifacts and products that consume less energy, are more respectful of the environment, and have a moderate impact on the environment when integrated and used in civil aviation, thus improving the energy efficiency of aircraft.

[0004] The Applicant is therefore working to reduce its climate impact by adopting ethical development and manufacturing methods and processes that minimize greenhouse gas emissions in order to reduce the environmental footprint of its activities.

[0005] This ongoing research and development work focuses on: new generation aircraft engines; lightweighting of equipment, in particular through the materials used and lighter onboard equipment; the development of electric power technologies to ensure propulsion; and aviation biofuels as an important complement to technological progress.

[0006] In order to increase the market acceptance of new aircraft, in particular electric turboprop aircraft, it is planned to phase-synchronize the aircraft's propellers ("sync-phase") in order to reduce the noise inside the aircraft. The aim is to ensure that the noise signature of these new electric turboprop aircraft does not exceed that of currently existing aircraft. In practice, this generally means using phase synchronization between the propellers to achieve a noise reduction relative to current hot turboprop aircraft of approximately 25 dB for noise levels typically experienced inside an aircraft, which can range from 85 dB to 100 dB.

[0007] It is known that phase synchronization between propellers involves measuring the rotational speed of the aircraft propellers, which is then used to synchronize the speed and rotation angle of these propellers. This measurement is usually performed using inductive or Hall effect sensors. However, in the case of propellers driven by medium and high power electric thrusters, the electromagnetic interference related to the electric power of the thrusters exacerbates this limitation in an environment where the sensors are already limited, especially in terms of vibration and temperature. The electromagnetic sensitivity of the sensors usually used is too low, reducing the accuracy of their measurements.

[0008] Therefore, a reactive and accurate measurement of the propeller rotation speed with low sensitivity to electromagnetic interference is preferred. Summary of the invention

[0009] In this respect, the present invention is the result of technical research focused on significantly improving the performance of aircraft and, in this sense, contributes to reducing the impact of aircraft on the environment. To this end, the present invention relates to a device for measuring the rotation speed of an aircraft propeller, comprising:

[0010] -Optical speed sensor;

[0011] - an optical fiber connected to the optical speed sensor and intended to be connected to a control unit of the aircraft; and

[0012] - at least one target object, which is configured to follow the rotation of the propeller,

[0013] The optical speed sensor is configured to detect a target object.

[0014] Optical fibers are completely immune to electromagnetic interference, and so are optical speed sensors. This creates a measurement device for the propeller's rotational speed that is completely insensitive to its electromagnetic environment, and in particular to interference associated with cables or converters using power electronics. Thanks to this speed measurement of the propeller, the aircraft's control system will be able to accurately and constantly verify that the propeller has the same speed as the other propellers.

[0015] According to a particular feature of the invention, the optical speed sensor is fastened to a fixed part of the engine driving the propeller.

[0016] For example, it is fastened to the fixed structure that supports the engine, ensuring that the optical speed sensor is not susceptible to propeller and engine vibrations.

[0017] According to another particular feature of the invention, the optical fiber is placed along the wing of the aircraft comprising said propeller.

[0018] For example, it may extend along the leading edge of the wing. This advantageously reduces the required length of optical fiber, since it enables the optical speed sensor and the control unit of the aircraft to be connected via the shortest path. Furthermore, this also facilitates the feed-through facilities of existing cables or wire harnesses, connecting the power supply (converter) to the electric propeller engine, guiding the optical fiber to the control unit of the aircraft. Advantageously, a thermal protection sheath will be provided for the optical fiber, which will protect the optical fiber from the effects of high temperatures, in particular those generated by the high voltage electrical cables when the optical fiber runs along the leading edge of the wing. This thermal protection is made of a polymer, such as polytetrafluoroethylene (PTFE).

[0019] The optical fiber can also travel along the trailing edge of the wing. This means that the optical fiber is routed in a non-cluttered area of the wing. In addition, by passing through the trailing edge, the optical fiber is kept at a sufficient distance from the power cables that may experience significant self-heating, and the thermal protection layer can be dispensed with.

[0020] According to one embodiment of the present invention, the target is placed on the engine shaft driving the propeller or on the shaft carrying the propeller, and the optical speed sensor is placed on a radial axis perpendicular to the axis of rotation of the engine shaft or the shaft carrying the propeller.

[0021] By placing the target on the engine shaft or the propeller shaft, radial measurements can be made to determine the rotational speed of the propeller. This arrangement integrates the optical sensor as closely as possible onto the mobile component carrying the measurement target. This proximity ensures a minimum mechanical clearance between the fixed component carrying the sensor and the mobile component carrying the target. In other words, this ensures a minimum relative displacement between the mobile component and the sensor performing the measurement due to vibration phenomena. This improves the measurement accuracy and its invariance with respect to vibration conditions.

[0022] According to another embodiment of the present invention, the target is placed on a flange fastened to the engine shaft driving the propeller or the shaft carrying the propeller, and the optical speed sensor is opposite the flange in a direction parallel to the engine shaft or the shaft carrying the propeller.

[0023] By placing the target on a workpiece rotating with the propeller, axial measurements of the rotational speed of the propeller can be made.

[0024] According to a specific feature of the present invention, the target is a shape and / or color contrast and / or hole.

[0025] For example, the target can be a specific shape present on the engine shaft, the shaft carrying the propeller, or a flange fastened to one of these two shafts. For example, the shaft or the flange can be toothed, and the target can be formed by a tooth or the hollow part between two teeth, or can be formed by a hole present on the shaft or the flange.

[0026] In addition, the target can also be a patch of color or in contrast to the background color present on the shaft or the flange. For example, this patch of color can be formed by white paint and / or reflective paint.

[0027] The target can also be formed by a colored mark or shape to improve the detection of the optical sensor. For example, it can be formed by teeth painted white present on the engine shaft, or by the shaft carrying the propeller or even the flange, where the shaft and the flange are dark in color in this case.

[0028] According to a particular feature of the invention, the device comprises a plurality of targets and the optical speed sensor is configured to detect the plurality of targets.

[0029] Having several targets can improve the accuracy of the speed measurement. In addition, all targets can be the same, or different targets can be selected. According to another aspect, the targets can be equidistant from each other or unequally spaced. In addition to measuring the rotation speed, having different targets and / or unequally spaced targets can help detect the rotation direction of the propeller.

[0030] According to another particular feature of the invention, the distance between the one or more targets and the optical speed sensor is between 1 mm and 10 mm.

[0031] Another object of the invention is an aircraft comprising a plurality of propellers, each of which comprises a measuring device according to the invention.

[0032] Thus, in this aircraft, each propeller of the aircraft comprises a measuring device according to the invention. In addition, all devices may be identical or different. For example, it may be chosen to route the optical fiber along the leading edge of a propeller present on one wing and along the trailing edge of a propeller present on another wing. For some propellers, the optical speed sensor may also be axially oppositely placed to a flange fastened to the engine shaft or to the shaft carrying these propellers, and for other propellers, the optical speed sensor may be placed on an axis radial to the axis of rotation of the engine shaft and the shaft carrying these other propellers. The number of targets between different propellers, and / or the type of targets, and / or the distances between targets of the same propeller, etc. may still vary. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other characteristics and advantages of the invention will emerge from the following description, made with reference to the accompanying drawings, which show an embodiment without any limiting character.

[0034] [ Figure 1A ] Figure 1A An aircraft wing comprising three propellers according to an embodiment of the invention is schematically and partially shown, the rotation speed of the propellers being measured by a measuring device.

[0035] [ Figure 1B ] Figure 1B A close-up of an aircraft wing is shown schematically and partially, in particular the attachment to Figure 1A One of the propellers of one of the turbopropellers is on a wing of the aircraft.

[0036] [ Figure 2A ] Figure 2A A device for measuring the rotation speed of a propeller according to another embodiment of the present invention is schematically and partially shown.

[0037] [ Figure 2B ] Figure 2B Schematically and partially shown Figure 2A The target of the measuring device.

[0038] [ Figure 3 ] Figure 3 A device for measuring the rotation speed of a propeller according to another embodiment of the present invention is schematically and partially shown. DETAILED DESCRIPTION

[0039] The invention will be described below in the specific context of an aircraft comprising an electric propeller.An electric propeller refers to an assembly comprising a propeller and an electric motor driving the propeller.

[0040] Figure 1A and Figure 1B Schematically and partially shown is an aircraft wing 140 comprising three propellers 110, 112, 114, each connected to a respective electric motor 111, 113, 115 and the rotation speed of each propeller can advantageously be measured by a measuring device as described below.

[0041] The rotation speed measurement device of a propeller such as propellers 110, 112, 114 includes an optical speed sensor, an optical fiber 130 connected to the optical speed sensor and a control unit 160 of the aircraft, and at least one target configured to track the rotation of the propeller in question. The optical speed sensor is configured to detect one or more targets. The control unit 160 may include an optical signal to digital logic signal converter to interpret the measurement value of the optical speed sensor. Because the optical fiber is not subject to electromagnetic interference, the optical signal is transmitted from the optical speed sensor to the control unit 160 without interference. This helps to improve the accuracy of the propeller speed measurement in question.

[0042] refer to Figure 1B In this embodiment, the optical fiber 130 is placed along the leading edge BA of the wing 140, which includes the propeller in question, such as the propeller 110. This reduces the length of the optical fiber 130, because it is placed as close as possible to the speed sensor and travels through the shortest path between the speed sensor and the control unit 160. A protective thermal layer can surround the optical fiber 130 to protect it from the heat generated by the high-voltage electrical cables that are usually routed along the leading edge BA of the wing 140, which power the electric motor of the propeller 110. The thermal protector can be made of a polymer material, such as PTFE.

[0043] Alternatively, one may choose to route the optical fiber 130 along the trailing edge BF of the wing 140 if one wishes to reduce clutter of services running along the leading edge BA (such as high voltage electrical cables, feathering actuators for the propellers, servomotors, etc.), or if the objective is to thermally protect the optical fiber 130 .

[0044] The following will refer to Figure 2A , Figure 2B and Figure 3 The rotation speed measurement devices of propellers 110, 112, and 114, in particular the optical speed sensors and targets, are described in detail.

[0045] Figure 2A The propeller speed measuring device 210 according to an embodiment of the present invention is schematically and partially shown. Figure 2A As shown in the propeller 211, the advantage of this device in the aerodynamic plane is that it has no effect on the drag of the aircraft. Figure 2B Shows Figure 2A The three targets 251, 252 and 253 of the device 210.

[0046] As reference Figure 1A and Figure 1B As shown, the measuring device 210 includes an optical speed sensor 220, an optical fiber 230 connected to the optical speed sensor 220 and the aircraft control unit, and at least one target 251, 252, 253 configured to track the rotation of the propeller 211. In this example, the device 210 includes three targets 251, 252, 253 (the third target is at Figure 2A Not visible in , but in Figure 2B 251, 252, 253, they are equidistant relative to each other. Thus, the optical speed sensor 220 is configured to detect these three targets 251, 252, 253.

[0047] The targets 251, 252, 253 are placed on a flange 250, which is fastened to a shaft 270 carrying the propeller 211. In the present example, they are formed by a color contrast on the flange 250. If the flange 250 is dark, such as black or dark grey, the targets 251, 252, 253 are light, such as white. Or conversely, if the flange 250 is light, the targets 251, 252, 253 can be dark. The contrast between the targets to be detected and the background can be enhanced by using a reflective paint, or conversely, by using an absorptive paint for the targets.

[0048] The optical speed sensor 220 is fixed to a fixed part of the engine driving the propeller 211, in particular it is placed opposite the flange 250 according to a direction X' parallel to the axis of rotation X of the shaft 270 carrying the propeller 211. The axial mounting of the speed sensor 220 relative to the longitudinal axis of the engine (axis X) ensures that the resistance of the machine is not disturbed at the aerodynamic level, thanks to its integration and molding in the housing of the propeller engine of the propeller 211.

[0049] In the present example, the targets 251, 252, 253 are present on a flange 250 fastened to a shaft 270 carrying the propeller 211, but they could also be present on another flange or another workpiece, for example a flange of larger diameter, fixed to the shaft of the engine driving the propeller 211. If this is the case, the optical speed sensor 220 would be relative to this new flange or this new workpiece according to a direction parallel to the axis of rotation of the shaft of the engine.

[0050] Figure 3 A device 310 for measuring the rotation speed of a propeller according to another embodiment of the present invention is schematically and partially shown.

[0051] As in the first embodiment just described, the measuring device 310 comprises an optical speed sensor 320, an optical fiber ( Figure 3 ), and at least one target 351, 352, 361, 362, 371, 372 configured to track the rotation of the propeller.

[0052] In this second embodiment, as will be described later, the sensor and the associated target are more closely integrated into the internal part of the motor, which is more conducive to ensuring minimum mechanical clearance, which minimizes the relative displacement between the fixed sensor and the moving member that rotates with the propeller and carries the target in a vibration environment. This improves the measurement accuracy and invariance to vibration conditions.

[0053] In more detail, the optical speed sensor 320 is fastened to a fixed part of the engine driving the propeller. More specifically, in this example, it is fastened to a fixed structure supporting or enclosing the engine and is placed on an axis XR radial to the axis of rotation X of the shaft and its flange 370. In order to measure the rotation speed of the propeller, the optical speed sensor 320 is also configured to detect at least one of the groups of targets (351, 352), (361, 362) and (371, 372).

[0054] The targets are placed on a part of the engine driving the propeller, which part can rotate with the propeller, in the example shown, the front flange 370 of the engine shaft, more precisely, on a part of this mobile part. These targets can be of several types: targets 351, 352 and 371, 372 are bumps or protrusions formed on a part of the mobile part, in particular targets 371, 372 also show a color contrast with targets 351 and 352; targets 361, 362 are holes, in particular hollow shapes formed on a part of the mobile part. If the sensor 320 is configured to detect several groups of these targets (351, 352), (361, 362) and (371, 372), it can also determine the direction of rotation of the propeller if, for example, the contrast of the target groups is different or the targets are not equidistantly placed.

[0055] In this example, the target 351, 352, 361, 362, 371, 372 is present on the front flange 370 of the shaft engine driving the propeller. In a variant, the target may be present on the engine shaft driving the propeller. If this is the case, the optical speed sensor 320 will be placed on a shaft radial to the axis of rotation of the engine shaft.

[0056] For reference Figure 2 and Figure 3 In both embodiments described, the optical fiber runs along the wing to the propeller, the rotational speed of the propeller is to be measured, either along the leading edge or the trailing edge.

[0057] If the wing, or more generally the aircraft, comprises several propellers, at least two propellers, the rotation speed of which is to be measured, as many devices according to the invention as there are propellers can be placed. The optical fiber of each of these devices can run along the leading edge or the trailing edge of the aircraft wing, or even be distributed between the edges of the two wings of the aircraft, in order to optimize the space requirements of the wing.

[0058] As for the objects present in these devices, their number may vary from device to device, and their shape or location may also vary.

[0059] Whatever the embodiment, if several targets are present in the measuring device, they can be equidistant from one another or placed at variable distances if the aim is also to determine the direction of rotation of the propeller.

[0060] Regardless of the embodiment, the distance between the target and the optical speed sensor is between 1 mm and 10 mm.

[0061] Regardless of the embodiment, the optical speed sensor is an optical sensor that exhibits an accuracy of less than one degree. For example, it is a slot or circular sensor.

Claims

1. A device (210, 310) for measuring the rotation speed of a propeller (110, 112, 114, 211) of an aircraft, include: - an optical speed sensor (220, 320); - an optical fiber (130, 230) connected to the optical speed sensor and intended to be connected to a control unit (160) of the aircraft; and - at least one target (251, 252, 253, 351, 352, 361, 362, 371, 372) configured to track the rotation of the propeller (110, 211), The optical speed sensor is configured to detect the target object.

2. The measuring device according to claim 1, It is characterized in that The optical speed sensor is fastened to a fixed part of an engine driving the propeller.

3. The measuring device according to claim 1 , It is characterized in that The optical fiber (130) is placed along a wing (140) of an aircraft including the propeller (110).

4. The measuring device according to any one of claims 1 to 3, It is characterized in that A thermal protection layer surrounds the optical fiber.

5. The measuring device (310) according to any one of claims 1 to 4, It is characterized in that The target (351, 352, 361, 362, 371, 372) is placed on the front flange (370) of the engine shaft driving the propeller, or on the shaft carrying the propeller, and the optical speed sensor is placed on a radial axis (XR) perpendicular to the rotation axis (X) of the engine shaft or the shaft carrying the propeller.

6. The measuring device (210) according to any one of claims 1 to 4, It is characterized in that The target (251, 252, 253) is placed on a flange (250), which is fastened to an engine shaft driving the propeller, or a shaft (270) carrying the propeller, and the optical speed sensor (220) is opposite to the flange according to a direction (X') parallel to the rotation axis (X) of the engine shaft or the shaft carrying the propeller.

7. The measuring device according to any one of claims 1 to 6, It is characterized in that The target objects are shape and / or color contrast objects and / or holes.

8. The measuring device according to any one of claims 1 to 7, It is characterized in that A plurality of targets are included, and the optical speed sensor is configured to detect the plurality of targets.

9. An aircraft comprising a plurality of propellers, in, Each propeller comprises a measuring device according to any one of claims 1 to 8.

Images