Obstacle warning system for a rotary-wing aircraft

Abstract

Equipped with an obstacle warning system for a rotary-wing aircraft: - a rotor (101) with at least one light source (102) on at least one rotor blade RB (103) of the rotor (101); - a system (104) for detecting obstacles HIN n (105) in a rotary-wing environment, wherein the system (104) is configured and designed to detect obstacles HIN n (105) - whose positions POS(HIN n ) relative to the rotary-wing aircraft and / or - Azimuth angle α(TO) n ), among which the obstacles HIN n (105) are arranged as seen from the rotary-wing aircraft and / or - Azimuth angle ranges αB(HIN) n ), which overcome the respective obstacles. n (105) each occupy as seen from the rotary-wing aircraft, and - Distances DIS(TO) n ) between rotary-wing aircraft and the respective obstacles TOWARDS n (105) and / or time derivatives of the distances DIS(HINn ) and / or a respective obstacle TOWARDS n (105) concerning risk assessment RISK(HIN n ) to determine, with n = 1, 2, ..., N and N ≥ 0; - a rotation angle detection unit (106) for detecting a current rotation angle Ψ R of rotor blade RB (103); and - a control unit (107) for controlling the at least one light source (102) on the rotor blade RB (103), wherein the control of the light source (102) depends on at least one of the following three points: ◯ Positions POS(HIN) n ) ◯ Azimuth angles α(HIN) n ) ◯ Azimuth angle ranges αB(HIN) n ), and depending on distances DIS(HIN n ) and / or their temporal derivatives and / or a risk assessment RISK(HIN n ) of the respective obstacle TOWARDS n (105) and depending on the angle of rotation Ψ R of the rotor blade RB (103).

Description

[0001] The invention relates to an obstacle warning system for a rotary-wing aircraft, in particular for a helicopter. Background of the invention

[0002] From 1982 to 2006, 166 aircraft accidents involving rotating propellers and rotors occurred. Of these, 29 accidents were linked to helicopters. The average number of annual accidents peaked at 25.6 in the 1970s [1]. This translates to an average of 1.2 personal injuries per year caused by helicopter rotors during this period. Personal injuries resulting from collisions between helicopters and objects are not included in this figure.

[0003] The accident analysis of the years 2005-2008 by the European Helicopter Safety Team (EHST) [2] leads to the following conclusions: The main cause of fatal helicopter accidents in commercial air transport can be attributed to pilot error due to situational misjudgments and incorrect actions. In operational areas such as Emergency Medical Services (EMS) and Search and Rescue (SAR), poor visibility and approaches to obstacles and terrain are often part of a mission [3]. Even in the years 2017 to 2021, approximately a quarter of helicopter accidents were still related to human factors (HF) and human performance (HP), as shown in the EASA accident report of 2022 [4]. A further breakdown of these accidents reveals that 44% can be attributed to a lack of situational awareness and insufficient situational perception on the part of the pilot.

[0004] For these reasons, improving the visibility of rotating rotor blades seems sensible in order to improve situational awareness and thus the decision-making and actions of helicopter pilots.

[0005] Color patterns applied to rotor blades were an initial approach to reducing the danger posed by rotating rotors and propellers and did indeed have a positive effect on their perception. However, such patterns can also impair the pilot's vision due to potential flickering [1]. Similar to color patterns, the increasingly common availability of illuminated rotor blade tips (RSB) can provide a visual indication of a rotating rotor blade for both bystanders and the crew. This is particularly true in poor visibility or darkness.

[0006] Currently known general collision avoidance systems for rotary-wing aircraft include the following: - Honeywell's HTAWS (“Helicopter Terrain and Warning System”), - Sandel Avionics HeliTAWS® with the WireWatch® display for high-voltage power lines, - Rockwell Collins HELISURT, - Garmin's WireAware™.

[0007] Document [5] provides a good market overview of commercial systems. Most of the systems mentioned use a head-down display (HDD) as the primary output for obstacle information, often supplemented by audible signals. In principle, the information from such systems can also be displayed in the pilot's field of vision using head-up displays (HUDs) or helmet-mounted displays (HMDs). Reference [3] describes the development of the Obstacle Proximity Lidar System (OPLST) by AugustaWestland. This system was developed for hovering flight, particularly for EMS and SAR operations in alpine regions, and serves to prevent collisions between obstacles and the rotors. Similar to the previously presented rotor blade tip illumination (RSB) for obstacle warning, this system aims to improve pilots' situational awareness and reduce workload by simplifying obstacle approach procedures.A rotor blade tip light (RSB) can provide pilots with greater awareness of the rotor diameter, particularly at night, thus enabling them to better judge distances to potential obstacles. In addition to improving safety during, for example, formation flying at night and in adverse weather conditions, an RSB can also contribute to improved safety on the ground. In 2021, the Bavarian Ministry of the Interior ordered eight H145-D3 helicopters equipped with a simplified version of the RSB [6]. This represents one of the first civilian applications of a rotor blade tip light (RSB) in Germany. The system consists of two lights that illuminate the rotor blades and a fluorescent material at the blade tip. The afterglow of the illuminated material at the blade tips thus illuminates the entire rotor circle in a constant color.The rotor tip lights (RSBs) used primarily in military applications to date often comprise more complex systems with active light sources mounted at the rotor blade tips. Slip rings on the rotor mast can be used for power supply and control. The use of piezoelectric elements or a permanent magnet generator to power the lights is also known. Both are attached directly to the rotor and are powered by its rotation (magnetic coils on the mast for power generation) or the movement of the rotor blades (piezoelectric elements in the rotor blade) [7]. One such active system is offered, for example, by the manufacturer COBHAM. The system consists of identical light sources (“Rotor Tip Lights, RTL”) and a control unit (“Rotor Tip Light Unit, RTLU”). The light sources emit green light at an angle of 120° from the blade tip.The light is compatible with night vision devices and its intensity can be adjusted via a rotary knob [8]. In the case of the NH90, a green electroluminescent light source is mounted on the underside of each of the four main rotor blades. Similar to what has been described previously, these are controlled / adjusted by a control unit and a rotary potentiometer [9]. A system from Luminator Aerospace includes, in addition to LEDs that emit white light, the capability to emit infrared radiation

[10] . In a project that received funding from the US Small Business Innovation Research (SBIR) program in 2011, the RSB was also intended to be used as a supplement to the position lights. Compared to the usual mounting on the helicopter fuselage, the improved visibility provided by an RSB was justified by the greater distance between the position lights (main rotor diameter).Wireless communication between the individual light sources (usually LEDs) and an operating / control unit in the helicopter cockpit was intended to enable a rapid, angle-dependent change of the respective colors, thus fulfilling the requirements for the position lights. Information on the continuation of this project is not yet available

[11] .

[0008] As can be seen from the state of the art, systems and approaches already exist that warn helicopter pilots of potential collisions by displaying an obstacle on a hard disk drive (HDD), providing acoustic cues, or offering haptic feedback – also in various combinations. Particularly when using acoustic and haptic cues, misinterpretations can occur with an increased probability, as described, for example, in study

[12] . Furthermore, to actually increase situational awareness, visual information should ideally be displayed within the pilot's field of vision. This way, the pilot does not have to look unnecessarily at the instrument panel in critical situations when monitoring the surroundings is required.

[0009] Due to the limited area of ​​view of a HUD, which provides supplementary information, only a slight increase in situational awareness, comparable to that of a HDD, can be expected. A similar display within the pilot's field of vision would also be possible with a HMD. In military applications, this would additionally allow for undetectable use. However, warnings to ground personnel, for example, would not be possible. Furthermore, overloading the field of vision with excessive symbols during critical phases of flight must be strictly avoided, and the operation of HMDs in aviation is often associated with high costs.

[0010] Neither the HDD, HUD, nor HMD provides additional warnings to other crew members or ground personnel. However, a simple RSB (e.g., by illuminating and fluorescing the rotor blades) can improve the crew's and ground personnel's perception of the main rotor dimensions. Active obstacle warning is not possible with this method. [1] CE Rash, “Walking into Trouble,” Aviation Safety World, pp. 28-34, August 2006. [2] European Helicopter Safety Team (EHEST), “EHEST Analysis of 2000 - 2005 European Helicopter Accidents”, European Aviation Safety Agency (EASA), Cologne, 2010. [3] M. Brunetti, “The Guardian Project: Reasons, Concept and Advantages of a Novel Obstacle Proximity LIDAR System,” European Rotorcraft Forum, Southampton, 2014. [4] Safety Intelligence Department, “Annual Safety Review 2022,” European Aviation Safety Agency (EASA), Cologne, 2022. [5] M. Godfroy-Cooper, JD Miller, Z. Szoboslay and G. Hartnett, “Multimodal Pilot Cueing for 360° Situation Awareness”, European Rotorcraft Forum, Warsaw, Poland, 2019. [6] VK Thomalla, “The Bavarian police receive H145 helicopters with rotor tip lighting”, Aerobuzz.de. Accessed: January 8, 2024. [Online]. Available at: https: / / aerobuzz.de / helikopter / die-bayerischepolizei-erhaelt-h145-mitrotorspitzen-beleuchtung / [7] M. Landry, “Rotor blade visual lights,” US 7,854,590 B2. [8] COBHAM, “LED Rotor Tip Light System: Product Features” 2015. [9] FMV, Swedish Defence Materiel Administration, “Technical Description HKP14 BSWx”, Stockholm, 2012.

[10] Luminator Aerospace, “Blade Tip Lights”, Plano, Texas, USA.

[11] EMTEQ, “SBIR STTR America's Seed Fund,” October 18, 2010, https: / / www.sbir.gov / sbirsearch / detail / 381943.

[12] M. Müllhäuser, “Tactile cueing with active cyclic stick for helicopter obstacle avoidance: development and pilot acceptance”, CEAS Aeronaut J, Vol. 9, No. 1, pp. 27-37, Jan. 2018, doi: 10.1007 / s13272-017- 0271-2.

[0011] Further state of the art can be found in the following patent documents: - US Patent US 10,875,664 B1; and - Japanese publication of patent application JP 2014-58195 A.

[0012] The object of the invention is to provide an improved obstacle warning system for a rotary-wing aircraft that overcomes the aforementioned disadvantages.

[0013] The invention is defined by the features of the independent claims. Advantageous further developments and embodiments are the subject of the dependent claims. Further features, applications, and advantages of the invention will become apparent from the following description and the explanation of exemplary embodiments of the invention illustrated in the figures.

[0014] A first aspect of the invention relates to an obstacle warning system for a rotary-wing aircraft, comprising: - a rotor with at least one light source on at least one rotor blade RB of the rotor, in particular the main rotor; - a system for detecting a number N of obstacles HIN n in a rotary-wing environment, the system being configured and designed to detect obstacles HIN n , whose positions POS(HIN n ) relative to the rotorcraft and / or azimuth angle α(HIN) n), under which the respective obstacles HIN n are arranged as seen from the rotary-wing aircraft and / or azimuth angle ranges αB(HIN) n ), which overcome the respective obstacles. n As seen from the rotary-wing aircraft, each position is occupied, and distances DIS(HIN) n ) between rotary-wing aircraft and the respective obstacles TOWARDS n and / or time derivatives (e.g. ∂DIS(HINn)∂t, ∂2DIS(HINn)∂t2,...) the distances DIS(HIN n ) and / or a respective obstacle TOWARDS n relevant risk assessment RISK(HIN) n ) to determine, with n = 1, 2, ..., N and N ≥ 0; - a rotation angle detection unit for detecting a current rotation angle Ψ R of the rotor blade RB; and - a control unit for controlling the at least one light source on the rotor blade RB, wherein the control of the at least one light source depends on at least one from the following list: ◯ Positions POS(HIN) n ) ◯ Azimuth angles α(HIN) n ) ◯ Azimuth angle ranges αB(HIN) n ), and depending on distances DIS(HIN n ) and / or their temporal derivatives (e.g. ∂DIS(HINn)∂t, ∂2DIS(HINn)∂t2,...) and / or a risk assessment RISK(HIN n ) of the respective obstacle TOWARDS n and depending on the angle of rotation Ψ R of the rotor blade RB.

[0015] The "rotor" is preferably the main rotor of the rotary-wing aircraft. If the rotary-wing aircraft has two main rotors, a corresponding obstacle warning system is preferably provided for each of the main rotors.

[0016] Advantageously, the control unit is designed and configured in such a way that it can determine the light intensity emitted by the light source and / or a light color and / or light pulse frequency depending on the determined relative positions POS(HIN). n) and / or azimuth angles α(HIN) n ) and / or azimuth angle ranges αB(HIN) n ), and distances DIS(TO n ) and / or their temporal derivatives (e.g. ∂DIS(HINn)∂t, ∂2DIS(HINn)∂t2,...) and / or a risk assessment RISK(HIN n ) and from the angle of rotation Ψ R the rotor blade RB is controlled according to predefined settings / functions.

[0017] The environment of the rotorcraft can advantageously be divided into several, e.g., three distance spheres (e.g., sphere 1: DIS(HIN)). n ) = 0 to 10m radius, sphere2: DIS(IN) n ) = 10 to 15m radius and sphere3: DIS(HIN n The zones are divided into areas with a radius of 15 to 20 meters, with each zone having specific and different settings / functions for controlling the light source. These settings can relate to the light intensity, color, and / or pulse frequency of the emitted light.

[0018] Advantageously, the obstacle warning system includes a control unit that allows, for example, a pilot of the rotary-wing aircraft to configure / change these predefined settings / functions. The control unit is advantageously designed and configured to output and / or display the currently valid or stored settings / functions for controlling at least one light source via the control unit.

[0019] Advantageously, at least one light source comprises one or more light-emitting diodes (LEDs). Advantageously, at least one light source is an infrared light source. Advantageously, at least one multi-colored LED is used as the light source. In the case of several light sources arranged on the rotor blade, at least one of these is advantageously an infrared light source. Advantageously, the LEDs emit at least two different colors of light. Advantageously, at least one light source is arranged in the distal end region of the rotor blade RB. Advantageously, at least one light source is arranged on the rotor blade RB in such a way that it does not (directly) dazzle a pilot of the rotary-wing aircraft during operation.

[0020] The HIN obstacle detection system is advantageous. n A radar system, a LiDAR system, or a combination of both. The HIN obstacle detection system ntransmits the data he has determined regarding POS positions (HIN) n ) and / or azimuth angles α(HIN) n ) and / or azimuth angle ranges αB(HIN) n ) and distances DIS(TO) n ) and / or their temporal derivatives (e.g. ∂DIS(HINn)∂t, ∂2DIS(HINn)∂t2,...) and / or the risk assessment RISK(HIN n ) to the control unit.

[0021] The HIN obstacle detection system n Advantageously includes an acquisition unit for acquiring sensor data on obstacles present in the vicinity of the rotary-wing aircraft. n , an evaluation unit for determining obstacles HIN n in the sensor data with their respective relative positions POS(HIN) n ) and / or azimuth angles α(HIN) n ) and / or azimuth angle ranges αB(HIN) n ) and distances DIS(TO) n ) and / or their temporal derivatives (e.g. ∂DIS(HINn)∂t, ∂2DIS(HINn)∂t2,...) and / or for the respective risk assessment RISK(HIN n ) of the identified obstacles TO n .

[0022] The HIN obstacle detection system n Advantageously, it includes a database containing information about obstacles, such as their positions (2D or 3D positions), obstacle type, geometry, material, etc. This information is advantageously used for comparison with sensor data and / or to supplement it for defining obstacles. n used.

[0023] The value of the risk assessment RISK(HIN) n ) represents a collision risk of the rotorcraft, in particular the rotor blades RB of the rotor with a respective identified obstacle HIN n A high value for RISK(HIN) is advantageous. n ) a high, a lower value for RISK(HIN) n ) a lower risk of collision.

[0024] The value of the risk assessment RISK(HIN) n ) of an obstacle TOWARDS n depends advantageously on its distance DIS(HIN) n ) and / or its temporal derivative(s) (e.g. ∂DIS(HINn)∂t, ∂2DIS(HINn)∂t2,...) and / or its azimuth angle α(HIN) n ) and / or azimuth angle range αB(HIN) n ) and / or a determined outline geometry of the obstacle HIN n and / or an identified material from which the obstacle HIN n exists, from. This list is not exhaustive and may change depending on the available data on the respective obstacles. n to be supplemented accordingly.

[0025] The relative distance DIS(HIN) n ) of an obstacle TOWARDS n Advantageously refers to a geometric fixed point of the respective rotary-wing aircraft. Advantageously, the fixed point lies on an axis of rotation of the main rotor of the rotary-wing aircraft.

[0026] The HIN obstacle detection system is advantageous. n The HIN obstacle detection system is located on board the rotary-wing aircraft. n It can also use drone sensors, aircraft sensors, and satellite sensors located at least partially outside the rotorcraft to detect obstacles (HIN). n in an environment of the rotary-wing aircraft. Data obtained from these rotary-wing external devices are advantageous in determining POS(HIN). n ), and / or α(HIN n ) and / or αB(HIN n ) and DIS(HIN n ), whose temporal derivatives (e.g. ∂DIS(HINn)∂t, ∂2DIS(HINn)∂t2,...) and / or for the respective risk assessment RISK(HIN n ) of the identified obstacles TO n This is taken into account and also transmitted to the control unit.

[0027] Advantageously, the azimuth angles α(HIN) are related n), the azimuth angle ranges αB(HIN n ) and the rotation angle Ψ R to a common reference direction. Advantageously, this common reference direction is the longitudinal direction of the rotary-wing aircraft, i.e., the direction in which the current longitudinal axis of the rotary-wing aircraft points.

[0028] In an advantageous first alternative further development, the control unit is designed and configured so that, provided there is no obstacle, HIN n detected in the environment, which has at least one light source at all current rotation angles Ψ R of the rotor blade RB is deactivated, i.e., it does not emit light.

[0029] Advantageously, the control unit is designed and configured according to the first alternative further development to activate at least one light source only when the current rotation angle Ψ R of the rotor blade RB an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n), in which an obstacle TOWARDS n is arranged, painted over.

[0030] Advantageously, the control unit is designed and configured according to the first alternative further development such that a rotational circle of the rotor blade RB is divided into a number M of stationary / fixed angular segments WA relative to the rotary-wing aircraft. m is subdivided, with m = 1, 2, ..., M and M > 1, where the control unit is designed so that at least one light source is only activated while the current rotation angle Ψ R of the rotor blade RB an angular section WA m sweeps out, in which an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n ) of an identified obstacle TOWARDS n lies.

[0031] Advantageously, the rotational circle of the rotor blade (the circle described by the tips of the rotor blades) is divided into 4, 8, 16 or 32 angular segments, i.e. M = 4 or M = 8 or M = 16 or M = 32.

[0032] The angular segments WA m are advantageous with respect to the current longitudinal direction of the rotary-wing aircraft, i.e., the current direction in which the longitudinal axis of the rotary-wing aircraft points, stationary or fixed.

[0033] Advantageously, the control unit is designed and configured according to the first alternative further development such that at least one light source is only activated while the current rotation angle Ψ R of the rotor blade RB, that angular section WA m sweeps out in which the azimuth angle α(HIN) n ) or the azimuth angle range αB(HIN) n ) of the obstacle TOWARDS n with the smallest distance DIS(HIN n) to the rotary-wing aircraft and / or the highest value of its time derivative(s) (e.g. ∂DIS(HINn)∂t,∂2DIS(HINn)∂t2,...) and / or the highest risk rating RISK(HIN) n ). For example, if the obstacle with the shortest distance to the rotary-wing aircraft lies in the angular segment WA. m=2 , with M = 8, the light source is only activated if the current rotation angle Ψ R of the rotor blade RB the entire angular section WA m=2 swept over. In all other angle sections WA m=1, 3, 4, 5, 6, 7, 8 , i.e., at the current rotation angle Ψ R those outside the angular segment WA m=2 The light source is not activated when lying down.

[0034] Advantageously, the control unit is designed and configured according to the first alternative further development in such a way that at least one light source is controlled in such a way that at least one of the following points applies when it is activated: - a constant light intensity is emitted over time, - a constant color of light is emitted over time, - Light pulses with a predetermined light pulse frequency F are emitted, - one of the respective distance DIS(HIN n The light intensity is emitted depending on the temperature. - one of the respective distance DIS(HIN n The light color is emitted depending on the conditions. - one of the respective distance DIS(HIN n ) dependent light pulse frequency F = F(DIS(HIN) n )) of light pulses is emitted, - one from a respective risk assessment RISK(HIN n The light intensity emitted depends on the user. - one from a respective risk assessment RISK(HIN n The light color is emitted depending on the conditions. - one from a respective risk assessment RISK(HIN n ) dependent light pulse frequency F = F(RISK(HIN) n)) of light pulses is emitted.

[0035] In an advantageous second alternative further development, the control unit is designed and configured so that, provided there is no obstacle, HIN n is / is detected in the environment, which at least one light source is controlled in such a way that it is visible at all current rotation angles Ψ R of the rotor blade RB is activated in such a way that the light source emits light with a constant light intensity and / or light color and / or light pulse frequency according to predefined initial settings.

[0036] While at least one light source in the further training according to the first alternative is used when no obstacle is detected HIN n If no light is emitted, then at least one light source in the further training according to the second alternative shines in the event of no detected obstacle. nLight with a predetermined constant light intensity and / or light color and / or light pulse frequency according to the first setting.

[0037] Advantageously, the control unit according to the second alternative development is designed and configured in such a way that it controls at least one light source in such a way that the light source changes its light intensity and / or light color and / or light pulse frequency F from the first settings to predetermined second settings only when the current rotation angle Ψ R of the rotor blade RB an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n ) overdraws, in which a recognized obstacle TOWARDS n lies.

[0038] As soon as the current rotation angle Ψ R of the rotor blade RB again sweeps out an azimuth angle α or an azimuth angle range αB in which there is no obstacle HIN nOnce determined, at least one light source will be controlled again according to the initial settings.

[0039] The second settings differ from the first settings in at least one of the following points: - the emitted light intensity and / or - the emitted light color and / or - the emitted light pulse frequency F.

[0040] The change from the first settings to the second settings is advantageous in such a way that it can be reliably perceived by the pilot even in his peripheral vision.

[0041] Advantageously, the control unit is designed and configured according to the second alternative further training so that the specified, aforementioned second settings are applied to the respective distances DIS(HIN). n ) and / or risk assessments RISK(HIN n ) depend, i.e., on the distances DIS(HIN n) and / or risk assessments RISK(HIN n ) may vary.

[0042] Advantageously, the control unit is designed and configured according to the second alternative further development such that a rotational circle of the rotor blade RB is divided into a number M of stationary / fixed angular segments WA relative to the rotary-wing aircraft. m is subdivided, with m = 1, 2, ..., M and M > 1, wherein the control unit is designed to control at least one light source in such a way that the light intensity and / or the light color and / or a light pulse frequency of the emitted light changes to predefined second settings, while the current rotation angle Ψ R of the rotor blade RB sweeps out an angular segment WA in which an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n ) of an obstacle TOWARDS n lies.

[0043] The angular segments WA mThese settings are advantageous with respect to the current longitudinal direction of the rotary-wing aircraft, i.e., the current direction in which the longitudinal axis of the rotary-wing aircraft points, which is stationary or fixed. Advantageously, the aforementioned second settings depend on the distance DIS(HIN). n ) and / or the risk assessment RISK(HIN n ) away.

[0044] The environment of the rotorcraft can thus be divided into, for example, three distance spheres (e.g., sphere 1: DIS(HIN)). n ) = 0 to 10m, Sphere2: DIS(IN) n ) = 10 to 15m and sphere3: DIS(TO) n ) = 15 to 20m) are divided, with each distance sphere having specific and different second settings of light intensity and / or light color and / or light pulse frequency of the emitted light.

[0045] Advantageously, the control unit is designed and configured according to the second alternative further development to change the light intensity and / or the light color and / or the light pulse frequency of the light emitted by the at least one light source from the first to the specified second settings only while the current rotation angle Ψ R of the rotor blade RB, that angular section WA m sweeps out in which the azimuth angle α(HIN) n ) or the azimuth angle range αB(HIN) n ) of the obstacle TOWARDS n with the smallest distance DIS(HIN n ) to the rotary-wing aircraft and / or the highest value of its time derivative(s) (e.g. ∂DIS(HINn)∂t,∂2DIS(HINn)∂t2,...) and / or the highest risk rating RISK(HIN) n ) lies.

[0046] Advantageously, the control unit is designed and configured according to the second alternative further development in such a way that at least one light source can be controlled in such a way that the specified second settings address one or more of the following points. - a predetermined light intensity - a predetermined light pulse frequency F of light pulses - one of the respective distance DIS(HIN n ) dependent light color - one of the respective distance DIS(HIN n ) dependent light intensity - one of the respective distance DIS(HIN n ) dependent light pulse frequency F = F(DIS(HIN) n ) of light pulses - one from a respective risk assessment RISK(HIN n ) dependent light color, - one from a respective risk assessment RISK(HIN n ) dependent light intensity, - one from a respective risk assessment RISK(HIN n) dependent light pulse frequency F = F(RISK(HIN) n )) of light pulses concerns / affect.

[0047] Advantageously, several light sources controlled by the control unit are arranged on the rotor blade RB.

[0048] Advantageously, the rotor has several rotor blades RB, each with at least one light source controlled by the control unit.

[0049] It is advantageous to arrange at least one light source at the distal end of a rotor blade RB so that the light source emits light in the peripheral field of vision of the rotorcraft pilot. It is also advantageous to arrange several light sources in the region of the distal end of a rotor blade RB.

[0050] A second aspect of the invention relates to a rotary-wing aircraft, in particular a helicopter, with an obstacle warning system as described above.

[0051] A third aspect of the invention relates to a method for operating an obstacle warning system for a rotary-wing aircraft, as described above, wherein the rotary-wing aircraft has a rotor with at least one light source on at least one rotor blade RB of the rotor, preferably the main rotor. The method comprises the following steps: - Obstacle detection n in a rotary-wing environment, - for detected obstacles TOWARDS n Determining - whose positions POS(HIN n ) relative to the rotary-wing aircraft and / or - Azimuth angles α(TO) n ), among which the obstacles HIN n are arranged in the surrounding area as seen from the rotary-wing aircraft and / or - Azimuth angle ranges αB(HIN) n ), which overcome the respective obstacles. n From the perspective of the rotary-wing aircraft, each area occupies a different space, and - relative distances DIS(HIN n) between rotary-wing aircraft and the respective obstacles TOWARDS n and / or temporal derivatives (e.g. ∂DIS(HINn)∂t,∂2DIS(HINn)∂t2,...) the distances DIS(HIN n ) and / or a risk assessment relating to a particular obstacle RISK(HIN) n ), with n = 1, 2, ..., N and N ≥ 0; - Capturing a current rotation angle Ψ R of the rotor blade RB; and - Control of at least one light source on the rotor blade RB by a control unit depending on at least one of the following three points: ◯ Positions POS(HIN) n ) ◯ Azimuth angles α(HIN) n ) ◯ Azimuth angle ranges αB(HIN) n ), and depending on distances DIS(HIN n ) and / or their temporal derivatives (e.g. ∂DIS(HINn)∂t,∂2DIS(HINn)∂t2,...) and / or a risk assessment RISK(HIN n ) of the respective obstacle TOWARDSn and depending on the angle of rotation Ψ R of the rotor blade RB.

[0052] Advantageously, the control unit controls a light intensity and / or a light color and / or light pulse frequency F emitted by at least one light source.

[0053] Advantageously, the azimuth angles α(HIN) are related n ), the azimuth angle ranges αB(HIN n ) and the rotation angle Ψ R to a common reference direction. Advantageously, this reference direction is the longitudinal direction of the rotary-wing aircraft, i.e., the direction in which the longitudinal axis of the rotary-wing aircraft points.

[0054] An advantageous first alternative further development of the procedure is characterized by the fact that, provided there is no obstacle, HIN n detected in the environment, which has at least one light source at all current rotation angles Ψ R The rotor blade RB is deactivated, so it does not emit any light.

[0055] An advantageous feature of a further development of the method according to the first alternative development is that at least one light source is only activated when the current rotation angle Ψ R of the rotor blade RB an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n ), in which a detected obstacle lies, sweeps over.

[0056] An advantageous feature of a further development of the method according to the first alternative development is that a rotational circle of the rotor blade RB is divided into a number M of angular segments WA that are stationary / fixed relative to the rotary-wing aircraft. m is subdivided, with m = 1, 2, ..., M and M > 1, where at least one light source is only activated while the current rotation angle Ψ R of the rotor blade RB an angular section WA m sweeps out, in which an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n) of an obstacle TOWARDS n lies.

[0057] An advantageous feature of a further development of the method according to the first alternative development is that at least one light source is only activated while the current rotation angle Ψ R of the rotor blade RB, that angular section WA m sweeps out in which the azimuth angle α(HIN) n ) or the azimuth angle range αB(HIN) n ) of the obstacle TOWARDS n with the smallest distance DIS(HIN n ) to the rotary-wing aircraft and / or with the highest values ​​of a time derivative of DIS(HIN n ) and / or with the highest risk rating RB(HIN) n ) lies.

[0058] The risk assessment RB(HIN) n ) of a detected obstacle TOWARDS n is advantageously determined based on one or more of the following points: - Distance DIST(TO) n ), - the azimuth angle range αB(TO)n ), - a determined outline geometry of the obstacle HIN n , - determined material properties of the obstacle HIN n , - a temporal derivative of the distance (∂DIS(HINn)∂t,∂2DIS(HINn)∂t2), - Type of obstacle TOWARDS n (Aircraft, building, person, etc.) - Obstacle's own speed (inwards) n , - etc..

[0059] An advantageous further development of the method according to the first alternative further development is characterized by the fact that at least one light source is controlled in such a way that at least one of the following points is true when it is activated: - a constant light intensity is emitted over time, - a constant color of light is emitted over time, - Light pulses with a predetermined light pulse frequency F are emitted, - one of the respective distance DIS(HIN n The light intensity emitted depends on the user. - one of the respective distance DIS(HIN n The light color is emitted depending on the conditions. - one of the respective distance DIS(HIN n ) dependent light pulse frequency F = F(DIS(HIN) n )) of light pulses is emitted, - one from a respective risk assessment RISK(HIN n The light intensity emitted depends on the user. - one from a respective risk assessment RISK(HIN n The light color is emitted depending on the conditions. - one from a respective risk assessment RISK(HIN n ) dependent light pulse frequency F = F(RISK(HIN) n )) of light pulses is emitted.

[0060] An advantageous second alternative development of the procedure is characterized by the fact that, provided there is no obstacle, HIN nis detected in the environment, which at least one light source is controlled in such a way that it is visible at all current rotation angles Ψ R of the rotor blade RB is activated in such a way that the light source emits light with a predetermined constant light intensity and / or light color and / or light pulse frequency F according to initial settings.

[0061] An advantageous feature of a further development of the method according to the second alternative development is that the light source is controlled in such a way that the light source changes its light intensity and / or light color and / or a light pulse frequency F to predetermined second settings when the current rotation angle Ψ R of the rotor blade RB an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n ), in which an obstacle TOWARDS n is arranged, painted over.

[0062] An advantageous feature of a further development of the procedure according to the second alternative further development is that the specified second settings for light intensity and / or light color and / or a light pulse frequency F each depend on the distance (HIN). n ) and / or the risk assessment RB(HIN n depend on each other.

[0063] An advantageous feature of a further development of the method according to the second alternative development is that a rotational circle of the rotor blade RB is divided into a number M of stationary / fixed angular segments WA relative to the rotary-wing aircraft. m is subdivided, with m = 1, 2, ..., M and M > 1, wherein at least one light source is controlled in such a way that it changes the light intensity and / or the light color and / or the light pulse frequency F of the emitted light to the specified second settings, while the current rotation angle Ψ Rof the rotor blade RB sweeps out an angular segment WA in which an azimuth angle α(HIN) n ) or an azimuth angle range αB(HIN) n ) of a detected obstacle TOWARDS n lies.

[0064] An advantageous feature of a further development of the procedure according to the second alternative further development is that the specified settings for light intensity and / or light color and / or a light pulse frequency F each depend on the distance (HIN). n ) and / or the risk assessment RB(HIN n depend on each other.

[0065] An advantageous feature of a further development of the method according to the second alternative development is that the light intensity and / or the light color and / or the light pulse frequency F of the at least one light source are only changed to the specified settings while the current rotation angle Ψ R of the rotor blade RB the angular section WA msweeps out in which the azimuth angle α(HIN) n ) or the azimuth angle range αB(HIN) n ) of the obstacle with the smallest distance DIS(HIN) n ) and / or the highest risk rating RB(HIN n ) lies.

[0066] An advantageous feature of the further development of the procedure according to the second alternative further development is that at least one light source is controlled in such a way that the specified second settings relate to at least one of the following points: - a predetermined light intensity, - a predetermined light pulse frequency F of light pulses, - one of the respective distance DIS(HIN n ) dependent light color, - one of the respective distance DIS(HIN n ) dependent light intensity, - one of the respective distance DIS(HIN n ) dependent light pulse frequency, F = F(DIS(HIN) n ) of light pulses, - one from a respective risk assessment RB(HIN n ) dependent light color, - one from a respective risk assessment RB(HIN n ) dependent light intensity, - one from a respective risk assessment RB(HIN n ) dependent light pulse frequency F = F(RB(HIN) n )) of light pulses.

[0067] The decisive advantage of the obstacle warning system proposed here is the indication of an approach by the rotary-wing aircraft, in particular by its main rotor, to obstacle objects. n for crew and ground personnel directly at the respective affected azimuth angle α(HIN) n ) or azimuth angle range αB(HIN) n ) or angle section WA m (Rotor circle segment) of the rotor circle.

[0068] The same applies conversely to an active approach to an obstacle object (TOWARDS). n(e.g., a person, vehicle, aircraft, surface-to-air missile, air-to-air missile, etc.) on the ground or in the air to the rotorcraft. The obstacle warning system can, in the event of, for example, an approaching person, vehicle, or aircraft, etc., on the ground to the rotorcraft, in particular a light color and / or light intensity and / or light pulse frequency emitted by the at least one light source for the respective azimuth angle α(HIN). n ) or azimuth angle range αB(HIN) n ) or angle section WA m This allows both the crew of the rotorcraft and, for example, ground personnel to be effectively warned of potential collision hazards during takeoff, landing, and loading / unloading operations.

[0069] The proposed obstacle warning system can be retrofitted to existing rotary-wing aircraft. The proposed obstacle warning system does not require any additional specific devices for displaying obstacle warnings, such as a HUD or HMD. The latter are often uneconomical for civil applications due to certification, operation, and the regular training required for pilots. One advantage of the proposed obstacle warning system over an HMD or HUD is its simple and easily understood warning symbols. This largely eliminates the risk of information overload for the pilot in critical situations. Furthermore, there is no possibility of the pilot's field of vision being obstructed or blocked by any kind of visual display, as the rotor disc (i.e., the circle described by the rotor blade tips) is typically...The obstacle warning system is located only in the pilot's peripheral field of vision, and after an initial familiarization period, the at least one light source only attracts the pilot's attention through a change in visual stimulus, i.e., a change in the light intensity and / or color and / or lift pulse frequency emitted by the at least one light source. The emitted light intensity and / or color and / or pulse frequency, or their predefined settings, are advantageously adjustable, particularly by the pilot. The at least one light source is advantageously positioned on the rotor blade in such a way that direct glare to the pilot is prevented. The proposed obstacle warning system provides the pilot with a warning of a potential collision obstacle (HIN) within their peripheral field of vision. nThis indicator function, unlike, for example, a hard disk drive (HDD), does not require the pilot to fix their gaze on the display for extended periods. In this way, the pilot can continuously monitor both the helicopter's movements and potential collision risks.

[0070] Further advantages, features, and details will become apparent from the following description, in which—possibly with reference to the drawings—at least one embodiment of the invention is described in detail. Identical, similar, and / or functionally equivalent parts are identified by the same reference numerals.

[0071] They show: Fig. 1. a highly schematic diagram of a proposed obstacle warning system for a helicopter, and Fig. 2. A top view of a rotor circle of the helicopter to illustrate an embodiment of the proposed obstacle warning system.

[0072] Fig. Figure 1 shows a highly schematic diagram of a proposed obstacle warning system for a helicopter. The obstacle warning system installed on the helicopter includes: a light source 102 arranged on a rotor blade RB 103 of the main rotor; a system 104 for detecting obstacles HIN n 105 in a helicopter environment, wherein the system 104 in this embodiment is configured and designed to detect obstacles HIN n 105 azimuth angle ranges αB(HIN) n ), which overcome the respective obstacles. n 105 each, as seen from the rotorcraft, and distances DIS(HIN) n ) between rotary-wing aircraft and the respective obstacles TOWARDS n to determine 105, with n = 1, 2 and N = 2.

[0073] The obstacle warning system also includes a rotation angle detection unit 106 for detecting a current rotation angle Ψ Rof the rotor blade RB 103 with respect to the longitudinal direction of the helicopter and a control unit 107 for controlling the one light source 102 on the rotor blade RB 103, wherein the control of the light source 102 depends on: the azimuth angle ranges αB(HIN n ) for each obstacle identified HIN n 105 and depending on distances DIS(HIN n ) between helicopter and the obstacles identified HIN n 105 and depending on the current rotation angle Ψ R of the rotor blade RB.

[0074] The control unit 107 is designed to ensure that, provided there is no obstacle, it n 105 is detected in the vicinity, which is a light source 102 at all current rotation angles Ψ R The rotor blade RB 103 is deactivated, so it does not emit any light.

[0075] Fig. Figure 2 shows a top view of a rotor circle of the helicopter to illustrate the present embodiment of the proposed obstacle warning system.

[0076] The rotation circle of the rotor blade RB 103 is divided into a number M = 16 of stationary / fixed angular segments WA relative to the helicopter. m subdivided, with m = 1, 2, ..., 16 and M = 16.

[0077] The control unit 107 is designed in this case to activate one light source 102 only while the current rotation angle Ψ R of the rotor blade RB 103 an angular section WA m sweeps out, in which an azimuth angle range αB(HIN) n ) for an obstacle TOWARDS n 105 were identified. Fig. These angular segments WA are 2 m Marked in thick black. This means that the light source 102 is only illuminated within the angular segment WA marked in thick black. mis continuously activated and otherwise inactive. "Activated" here means that the light source 102 is only active in the angular sections WA marked in thick black. m emits light with a predetermined light intensity and light color.

[0078] The angular segments WA m are only included for clarity Fig. 2 represented as dashed circular segments.

[0079] Although the invention has been further illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned as examples are truly only examples and are not to be understood in any way as limiting, for example, the scope of protection, the possible applications, or the configuration of the invention.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without leaving the scope of protection defined by the claims and their legal equivalents, such as a further explanation in the description. Reference symbol list 101 Rotor / Main rotor 102 light sources 103 Rotor blade RB 104 Obstacle Detection System HIN n (105) in a rotary-wing environment, 105 obstacles TOWARD n 106 Rotation angle detection unit for detecting a current rotation angle Ψ R of the rotor blade RB (103) 107 Control unit

Claims

Obstacle warning system for a rotorcraft comprising: - a rotor (101) with at least one light source (102) on at least one rotor blade RB (103) of the rotor (101); - a system (104) for detecting obstacles HINn(105) in the vicinity of the rotorcraft, wherein the system (104) is configured and designed to provide, for detected obstacles HINn(105): - their positions POS(HINn) relative to the rotorcraft and / or - azimuth angles α(HINn) at which the obstacles HINn(105) are arranged as seen from the rotorcraft and / or - azimuth angle ranges αB(HINn) that the respective obstacles HINn(105) occupy as seen from the rotorcraft, and - distances DIS(HINn) between the rotorcraft and the respective obstacles HINn(105) and / or time derivatives of the distances DIS(HINn) and / or a To determine the risk assessment RISK(HINn) for each obstacle HINn(105), with n = 1, 2, ..., N and N ≥ 0;- a rotation angle detection unit (106) for detecting a current rotation angle ΨR of the rotor blade RB (103); and- a control unit (107) for controlling the at least one light source (102) on the rotor blade RB (103), wherein the control of the light source (102) depends on at least one of the following three points:◯ positions POS(HINn)◯ azimuth angles α(HINn)◯ azimuth angle ranges αB(HINn), and depends on distances DIS(HINn) and / or their time derivatives and / or a risk assessment RISK(HINn) of the respective obstacle HINn(105) and depends on the rotation angle ΨR of the rotor blade RB (103). Obstacle warning system according to claim 1, wherein the control unit (107) is designed to control a light intensity emitted by the light source (102) and / or a light color and / or a light pulse frequency F. Obstacle warning system according to one of claims 1 or 2, wherein the control unit (107) is configured such that, if no obstacle HINn(105) is detected in the environment, at least one light source (102) is deactivated at all current rotation angles ΨR of the rotor blade RB (103), so that it does not emit light. Obstacle warning system according to claim 3, wherein a rotation circle of the rotor blade RB (103) is divided into a number M of stationary / fixed angular segments WAm relative to the rotor blade, with m = 1, 2, ..., M and M > 1, wherein the control unit (107) is configured such that the at least one light source (102) is only activated while the current rotation angle ΨR of the rotor blade RB (103) sweeps over an angular segment WAm in which an azimuth angle α(HINn) or an azimuth angle range αB(HINn) for an obstacle HINn(105) has been determined. Obstacle warning system according to claim 3, wherein the control unit (107) is configured such that the at least one light source (102) is only activated while the current rotation angle ΨR of the rotor blade RB (103) sweeps over the angular segment WAm in which the azimuth angle α(HINn) or the azimuth angle range αB(HINn) of the obstacle HINn(105) with the smallest distance DIS(HINn) and / or the highest value of a time derivative of DIS(HINn) and / or the highest risk assessment RISK(HINn) was determined. Obstacle warning system according to one of claims 1 or 2, wherein the control unit (107) is configured such that, if no obstacle HINn(105) is detected in the environment, the at least one light source (102) is controlled in such a way that it is activated at all current rotation angles ΨR of the rotor blade RB (103) such that the light source (102) emits light with a constant light intensity and / or light color and / or light pulse frequency F specified according to first settings. Obstacle warning system according to claim 6, wherein a rotation circle of the rotor blade RB (103) is divided into a number M of stationary / fixed angular segments WAm relative to the rotor blade, with m = 1, 2, ..., M and M > 1, wherein the control unit (107) is configured to control the at least one light source (102) such that it changes the light intensity and / or the light color and / or the light pulse frequency F of the emitted light from the first settings to predetermined second settings, only while the current rotation angle ΨR of the rotor blade RB (103) sweeps over an angular segment WAm in which an azimuth angle α(HINn) or an azimuth angle range αB(HINn) of a detected obstacle HINn(105) lies. Obstacle warning system according to claim 6, wherein a rotation circle of the rotor blade RB (103) is divided into a number M of stationary / fixed angular segments WAm relative to the rotor blade, with m = 1, 2, ..., M and M > 1, wherein the control unit (107) is configured to control the at least one light source (102) such that it changes the light intensity and / or the light color and / or the light pulse frequency F of the emitted light from the first settings to predetermined second settings, only while the current rotation angle ΨR of the rotor blade RB (103) sweeps over an angular segment WAm in which the azimuth angle α(HINn) or the azimuth angle range αB(HINn) of the obstacle HINn(105) with the smallest distance DIS(HINn) to the rotor blade and / or the highest risk assessment RISK(HINn) lies. Rotary-wing aircraft, in particular helicopters, with an obstacle warning system according to one of claims 1 to 8. Method for operating an obstacle warning system for a rotary-wing aircraft, wherein the rotary-wing aircraft has a rotor (101) with at least one light source (102) on at least one rotor blade RB (103) of the rotor (101), comprising the steps of: - detecting obstacles HINn(105) in a vicinity of the rotary-wing aircraft, - for detected obstacles HINn(105) determining - positions POS(HINn) of the obstacles HINn(105) relative to the rotary-wing aircraft and / or - azimuth angles α(HINn) at which the obstacles HINn(105) are arranged in the vicinity as seen from the rotary-wing aircraft and / or - azimuth angle ranges αB(HINn) that the respective obstacles HINn(105) occupy in the vicinity as seen from the rotary-wing aircraft, and - relative distances DIS(HINn) between the rotary-wing aircraft and the respective obstacles HINn(105) and / or time derivatives of the Risk assessments RISK(HINn) relating to distances DIS(HINn) and / or the respective obstacles HINn(105), with n = 1, 2, ..., N and N ≥ 0;- Detecting a current rotation angle ΨR of the rotor blade RB (103); and- Controlling the at least one light source (102) on the rotor blade RB (103) by a control unit (107) depending on at least one of the following three points:◯ Positions POS(HINn)◯ Azimuth angles α(HINn)◯ Azimuth angle ranges αB(HINn), and depending on distances DIS(HINn) and / or their time derivatives (e.g. ∂ DIS ( HIN n ) ∂ t , ∂ 2 DIS ( HIN n ) ∂ t 2 ,... ). and / or a risk assessment RISK(HIN n ) of the respective obstacle TOWARDS n (105) and depending on the angle of rotation Ψ R of the rotor blade RB (103).

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