method for piloting an aircraft having a plurality of dissimilar navigation sensors and an aircraft

Abstract

The present invention relates to a method for piloting an aircraft (1) having a suite (30) of sensors comprising a plurality of dissimilar navigation sensors (31). This method comprises the following steps: (i) determining (STP1) at least one flight condition parameter varying according to weather conditions or the position of the aircraft (1), (ii) selecting (STP2) a set of sensors (50) according to each flight condition parameter based on a selection model carried in said aircraft (1), said set of sensors (50) comprising at least one navigation sensor from said suite (30) and generating at least one piloting information, (iii) generating (STP3) with a control controller (20) at least one control signal for piloting the aircraft (1) based on at least each piloting information. (Shorthand figure: Figure 1)

Description

Title of the invention: Method for piloting an aircraft having a plurality of dissimilar navigation sensors and an aircraft

[0001] The present invention relates to a method for piloting an aircraft having a plurality of dissimilar navigation sensors, and an aircraft. In particular, such an aircraft may be a rotorcraft and / or an unmanned aerial vehicle commonly referred to as a drone.

[0002] An aircraft may have an autonomous piloting system equipped with at least one flight controller that controls actuators in order to guide the trajectory followed by that aircraft. The term "actuator" is to be interpreted broadly, this term being able to designate in particular any component capable of causing the movement or deformation of another component and may, for example, include cylinders, servo controls, motors...

[0003] This navigation system may include multiple sensors used to assess the aircraft's position relative to the external environment and flight conditions. These sensors may be very different. For convenience, each of these sensors is referred to as a "navigation sensor" because of its use during aircraft piloting. For example, an aircraft may include at least one airspeed sensor, at least two onboard ultrasonic sensors of an ultrasonic positioning system, and / or at least one monoscopic or stereoscopic camera operating in the visible or infrared frequency range, and / or at least one obstacle detection remote sensing system.Such an obstacle remote sensing system may include an obstacle detector known by the acronym LIDAR for "Light Detection And Ranging" or by the acronym LEDDAR for "LED Detection And Ranging" or even a RADAR detector for "Radio Detection And Ranging".

[0004] An aircraft can thus be piloted by an autonomous piloting system to take off, land or follow a trajectory with regard to the environment, in particular according to the signals emitted by the various navigation sensors of the aircraft.

[0005] However, an aircraft is inevitably required to fly in varying flight and environmental conditions that can impact the effectiveness of navigation sensors. For example, some sensors may be inaccurate in the presence of fog or bright sunlight.

[0006] Document US20170364095 describes a drone method comprising the following steps: determining quality information conveying the quality of images taken by a plurality of imaging systems, selecting at least one system imaging from among said plurality of imaging systems based on said quality information, generation of status information from said at least one selected imaging system, generation of a navigation signal to control the vehicle based on the status information. The quality information is based on a number of characteristic points of the captured images.

[0007] Document WO201863500 is unrelated to the problem of the invention and describes a method for adjusting the flight path of a drone based on meteorological data. An example of such a device will, in particular, pilot a drone along a flight path via a processor; intercept meteorological data identified by a meteorological source within a defined perimeter around the flight path via the drone's processor; and, when the meteorological data corresponds to undesirable weather conditions, adjust the flight path via the drone's processor to avoid an area corresponding to the meteorological source.

[0008] The present invention then aims to propose an innovative method for piloting an aircraft according to the environment and flight conditions.

[0009] In particular, the invention relates to a method of piloting an aircraft having a suite of sensors comprising a plurality of dissimilar navigation sensors.

[0010] The process may include a pilot phase comprising the following steps:

[0011] - determination of at least one flight condition parameter varying as a function of weather conditions or aircraft position, said at least one flight condition parameter being distinct from information relating to image quality,

[0012] - selection of a sensor set based on each flight condition parameter said at least one flight condition parameter according to a selection model onboard said aircraft, said sensor set comprising at least one navigation sensor from said sensor suite, said sensor set generating at least one piloting information,

[0013] - generation with a control controller of at least one control signal to pilot the aircraft, said at least one control signal being based at least on each piloting information of said at least one piloting information.

[0014] The term "dissimilar" means that the plurality of navigation sensors comprises sensors measuring the same parameter but using different techniques, and not simply identical redundant sensors. For example, the plurality of navigation sensors comprises at least one camera, at least one radar, and at least one lidar or LEDdar, each of these sensors being capable of detecting an object in the environment. As another example, the plurality of navigation sensors comprises a pitot tube sensor and a satellite navigation sensor for evaluating the aircraft's speed.

[0015] The expression "depending on each flight condition parameter of said at least one flight condition parameter" means that, in the presence of a single flight condition parameter, the model takes into account, in particular, a single flight condition parameter, and that in the presence of several flight condition parameters, the model takes them all into consideration. The term "each" can thus refer to a single parameter where appropriate.

[0016] The same applies to expressions used subsequently.

[0017] In particular, the expression "each control information of said at least one control information" means that in the presence of a single control information the control controller takes into account a single control information, and that in the presence of several control information the control controller takes them all into consideration.

[0018] Furthermore, the selected sensor set may include one or more sensors. Optionally, a sensor set may include so-called "same type" sensors measuring the same navigation parameter. The data emitted by these same type sensors are then merged, for example by applying a Kalman filter, to obtain a more robust value for this navigation parameter. As an illustration, two dissimilar sensors in the same sensor set each evaluate the aircraft's speed; a Kalman filter merges the two evaluated speeds to deduce a robust speed value.

[0019] An aircraft can be equipped with numerous sensors to perceive its near and far environment and its position. However, each sensor has its own optimal operating range. Depending on the situation, and particularly the environmental conditions, the accuracy of a sensor can vary. Since sensor processing times also differ, a sensor's effectiveness can vary depending on the aircraft's speed.

[0020] The method thus includes, at each iteration, a first step to evaluate the current flight conditions. These flight conditions may include meteorological conditions, such as, for example, strong sunlight, twilight conditions, the presence of rain, the presence of fog, etc. These flight conditions may also include positioning conditions, such as the orientation, position, or speed of the aircraft.

[0021] Flight condition parameters do not include image quality, evaluated for example with a number of characteristic points, unlike document US20170364095. The first step of the method then aims to evaluate the aircraft's situation with respect to the environment.

[0022] During a second step, the process involves selecting the sensor set the The most appropriate sensor set, for example, is selected from several stored sensor sets, taking into account the flight conditions and a predetermined model. The aircraft is then piloted using the most effective sensor set for the current situation, or even other fixed sensors. For example, the model stores sensor sets to be used for various flight situations.

[0023] For example, obstacles surrounding an aircraft can be detected using a camera or radar. A camera operating in the visible frequency range has the advantage of being able to detect multiple objects but is less effective in bright sunlight, while radar has more difficulty identifying close objects. Thus, according to this example, the method can allow the use of a sensor array including radar in bright sunlight, and a sensor array including a camera in low sunlight.

[0024] This method can therefore make it possible to understand, qualify, and quantify the flight environment at a given moment in order to choose the sensor(s) best suited at that given moment to pilot the aircraft.

[0025] The method may also include one or more of the following features.

[0026] According to one possibility, said determination of at least one flight condition parameter may include at least one of the following steps: measurement of a luminance of an environment of the aircraft, measurement of a luminous illuminance of said environment, evaluation of a luminous intensity of said environment, determination of a contrast of an object of an environment of the aircraft with respect to a background, measurement of a distance between the aircraft and an object of said environment.

[0027] Contrast can indeed make it possible to identify the presence of fog, for example. Optionally, a camera can take a series of images, with the control unit analyzing the images to determine said contrast using known techniques.

[0028] Luminance or illuminance can be used to determine the possible presence of strong sunlight. The distance between the aircraft and an object may, where appropriate, determine the use of a specific obstacle detection system, and for example, a sensor with a fast processing time when the aircraft is traveling at high speed.

[0029] According to a possibility compatible with the preceding one, said determination of at least one flight condition parameter may include the following steps: measurement of a light illumination of an environment of the aircraft, determination of a contrast of said environment with respect to a background, and measurement of a distance between the aircraft and an object of said environment.

[0030] This combination of measurements may be useful for determining the set of sensors based on the ambient light level and the distance between an obstacle and the aircraft.

[0031] According to a possibility compatible with the preceding ones, said determination of at least one flight condition parameter may include a step of determining at least one flight parameter of the aircraft, said selection of a set of sensors being carried out according to said at least one flight parameter.

[0032] In addition to weather conditions, flight parameters and images of aircraft behavior in space can influence the choice of sensor set.

[0033] For example, said at least one flight parameter may include a speed of movement of the aircraft.

[0034] For example, such a speed of movement is an airspeed.

[0035] By way of illustration, at high aircraft speeds, the method can enable the selection of a sensor array equipped with sensors that quickly provide the information required to optimize piloting and avoid an incident. At low aircraft speeds, the selected sensor array may include sensors requiring longer processing time, these sensors potentially being more precise in the typical scenario.

[0036] According to a possibility compatible with the preceding ones, the selection model can apply a selection step by fuzzy logic.

[0037] For example, each flight condition parameter may have values ​​belonging to several categories. The selection model can then store, for each flight condition parameter, laws providing for each category a level of membership, between 0% and 100%, depending on the value of the flight condition parameter.

[0038] Furthermore, the selection model stores a plurality of rules. Each rule designates a set of sensors based on at least one category of at least one flight condition parameter or even logical operators. A set of sensors includes at least one navigation sensor from said sensor suite.

[0039] According to a simple example, the aircraft's speed can be low, medium, or high depending on its value. One rule might indicate that a first set of sensors is required if the speed is low or medium, and another rule might indicate that a second set of sensors is required if the speed is high.

[0040] For example, said fuzzy logic selection step may include the following steps:

[0041] - determination, for each flight condition parameter of said at least one flight condition parameter, of at least one level of membership in a category associated with that flight condition parameter,

[0042] - determining a weighting level for a plurality of rules, each rule associating a set of sensors comprising at least one navigation sensor from said sensor suite and at least one level of membership in said category,

[0043] - determination of the sensor set, said sensor set being the set of sensors associated with the rule having the highest level of weighting.

[0044] The expression "of at least one level of membership in a category associated with this flight condition parameter" means that for each category of a flight condition parameter a level of membership is determined.

[0045] According to one possibility, a flight condition parameter can be measured by an immutable sensor, namely present in all possible sensor sets or not part of the sensor suite.

[0046] According to a possibility compatible with the preceding ones, said at least one flight condition parameter being able to be measured by a plurality of dissimilar sensors of said plurality of navigation sensors, said determination of at least one flight condition parameter is carried out by soliciting the set of sensors in force.

[0047] According to this possibility, at any given moment, the aircraft uses a set of sensors. This active set of sensors can be used to determine the value of at least one flight condition parameter.

[0048] According to another possibility, at startup, the aircraft can use a default set of sensors.

[0049] According to another possibility, at startup, the control controller analyzes the data transmitted by all the navigation sensors and determines the most accurate sensors, for example, with regard to interpretation thresholds. For example, a sensor providing a substantially constant value for a given time can be considered reliable and usable. The controller can also merge various measurements of the same parameter. The control controller then implements the method according to the invention.

[0050] The invention also relates to an aircraft equipped with a suite of sensors having a plurality of dissimilar navigation sensors.

[0051] This aircraft includes a control controller configured to apply the preceding method, said control controller being configured to:

[0052] - determine a current value of at least one flight condition parameter,

[0053] - select a sensor set including at least one navigation sensor said suite of navigation sensors, depending on each flight condition parameter of said at least one flight condition parameter according to a selection model onboard said aircraft, said set of sensors generating at least one piloting information,

[0054] - generate at least one control signal to pilot the aircraft based at least on each piece of piloting information of said at least one piece of piloting information.

[0055] For example, the command controller may include a centralized unit, such as part of a flight controller of a drone for example.

[0056] According to another example, the aircraft may include a remote and redundant system. For example, the flight controller may include a unit associated with each navigation sensor. Each unit receives information from all the sensors and implements the process. The unit associated with one of the sensors in the selected sensor set can then take control of the aircraft. This unit becomes a master unit and informs the other units. The master unit then generates the control signal(s).

[0057] According to one possibility, said plurality of navigation sensors may include at least the following components: a camera operating in the visible frequency range, a camera operating in the infrared frequency range, a system for measuring the speed of the aircraft relative to the air, a remote sensing system for an obstacle, an ultrasonic positioning system, a light illumination sensor.

[0058] In particular, the aircraft may have one or more of the following obstacle remote sensing systems: a RADAR, a LIDDAR, an LEDDAR.

[0059] The aircraft may include a weather RADAR.

[0060] According to a possibility compatible with the preceding ones, said aircraft comprises at least one powered unit, said at least one powered unit comprising at least one motor rotating at least one rotor, said control controller transmits said at least one control signal to an electronic speed controller of said at least one motor.

[0061] The invention and its advantages will become apparent in more detail in the following description, with illustrative examples given by reference to the accompanying figures, which represent:

[0062] [Fig.1] the [Fig.1], an aircraft according to the invention,

[0063] [Fig.2] [Fig.2], a flowchart showing the steps of the process according to the invention,

[0064] [Fig.3] [Fig.3], a diagram illustrating the change in the selected sensor set in flight,

[0065] [Fig.4] the [Fig.4], a diagram showing a level of membership with respect to a distance,

[0066] [Fig.5] the [Fig.5], a diagram showing a level of membership with respect to a speed,

[0067] [Fig.6] the [Fig.6], a diagram showing a level of membership with respect to an illumination,

[0068] [Fig.7] the [Fig.7], a diagram showing a level of membership with respect to a contrast, and

[0069] [Fig.8] [Fig.8], an example of a decision table.

[0070] Elements present in several separate figures are assigned a single reference number, unless otherwise indicated.

[0071] Fig. 1 presents an aircraft 1 according to the invention capable of applying the method of the invention.

[0072] This aircraft 1 may include at least one powered unit 5 contributing to the movement of the aircraft 1 in space. For example, each powered unit is carried by a cell not shown to avoid complicating the figure.

[0073] Such a motorized unit 5 is, for example, equipped with a rotor 6 comprising a plurality of blades rotated by at least one motor 7, possibly via a power transmission chain. Alternatively, a motorized unit 5 may include a jet engine or equivalent, for example.

[0074] In particular, [Fig. 1] describes an aircraft comprising at least one power unit 5 including at least one engine 7 equipped with an electronic speed controller 8, this engine 7 rotating at least one rotor 6. According to another example, a power unit may, for example, comprise two engines driving two rotors respectively, one engine driving two rotors...

[0075] According to one possibility, a motor 7 may be an electric motor, the electronic speed controller 8 being powered by a power distribution system 10. Such a power distribution system 10 may include an electrical power source 11, for example, an electric battery or the like. For example, the electrical power source 11 supplies power to a distribution board 12 which is electrically connected to each electronic speed controller 8.

[0076] Furthermore, [Fig. 1] illustrates a quadcopter aircraft 1 equipped with four motorized groups 5, each with a rotor 6. This is just one example; aircraft 1 could be a rotorcraft of other shapes or even an aircraft of another type. For example, aircraft 1 could be a helicopter.

[0077] Similarly, the aircraft 1 illustrated is a drone but could also include an onboard human pilot and piloting means maneuverable by that human pilot.

[0078] The preceding examples are given for illustrative purposes only, the term "aircraft" being to be interpreted in a broad sense.

[0079] Regardless of the nature of the aircraft and the powered group(s), the aircraft 1 includes a system participating in the piloting of the aircraft 1. This system may be autonomous or may transmit control signals operated by a human pilot.

[0080] This system includes a controller referred to as the control controller 20 for convenience. This control controller 20 is configured to emit at least one control signal in order to participate in piloting the aircraft 1. For example, this control signal transmits piloting information to a human pilot. According to In the example of [Fig.1], the control controller 20 transmits control signals respectively to the electronic speed controllers 8 to control the rotational speed of each rotor 6. This control controller 20 can be autonomous and / or can receive instructions given remotely by an antenna 16 or by controls 15 operated by a human pilot.

[0081] The control controller 20 may include a centralized processing unit 25 as shown in [Fig. 1], or several processing units 25 that may communicate with each other. The processing unit(s) 25 are connected to each motorized group, and / or, where applicable, to each control element. Such an element may take the form of an electronic speed controller 8, an actuator controlling a flap or the blade pitch, for example, or other components, an indicator providing a parameter value or displaying at least one symbol to participate in control, such as a symbol representing an obstacle to be avoided on a screen...

[0082] The processing unit(s) 25 may include, for example, at least one processor 21 and at least one memory 22, at least one integrated circuit, at least one programmable system, at least one logic circuit, these examples not limiting the scope given to the expression "processing unit". The term processor may refer to a central processing unit known by the acronym CPU, a graphics processing unit GPU, a digital signal processing unit known by the acronym DSP, a microcontroller, etc.

[0083] To generate the control signal(s), the control controller 20 cooperates at least with a suite of sensors 30 having a plurality of navigation sensors 31. The control controller 20 cooperates with flight condition sensors, these sensors being able to be part of said suite of sensors 30 or not.

[0084] The term "sensor" is to be interpreted broadly as referring to a system that generates a digital or analog signal representing a parameter, for example, an electrical signal representing a voltage representing a temperature, or other parameters. A sensor may thus include at least one measuring element that generates a measurement signal, or even at least one processing element that generates a measurement signal. The control controller 20 can determine the value of a parameter by receiving a signal, for example, a digital signal, directly carrying that value, or by decoding an analog signal, for example.

[0085] According to the illustrated example, at least one processing unit 25 is connected to each navigation sensor 31. According to another example, the control controller 20 includes at least one remote processing unit 25, optionally associated with a navigation sensor 31. According to one example, each navigation sensor 31 includes a processing unit 25 from the control controller 20. Reference 31 is subsequently assigned to each navigation sensor, each navigation sensor also having its own reference.

[0086] For example, the plurality of navigation sensors includes one or more of the sensors described below.

[0087] Thus the plurality of navigation sensors may include a camera 32, stereoscopic or not, operating in the visible frequency range.

[0088] The plurality of navigation sensors may include a camera 33 operating in the infrared frequency range.

[0089] The plurality of navigation sensors may include a system 34, 35 for measuring the aircraft's airspeed. Such a system may, for example, include a Pitot tube sensor 34 and / or a satellite navigation sensor 35, and / or another type of conventional sensor.

[0090] The plurality of navigation sensors may include a remote sensing system 36, 37, 38 for an obstacle. Such a system may include, for example, a RADAR 36 and / or a LIDDAR 37 and / or an LEDDAR 38.

[0091] The plurality of navigation sensors may include an ultrasonic positioning system 39.

[0092] The plurality of navigation sensors may include a light illumination sensor 40. For example, such a sensor may include an optoelectronic transducer inserted in a photoelectric cell.

[0093] The plurality of navigation sensors may include a rain sensor, a frost sensor, a weather radar, an inertial navigation system...

[0094] Regardless of the aspects and examples described above, the flight controller 20 is configured to apply the method of the invention by participating in the piloting of the aircraft 1 using, at each instant of the applied method, the sensor(s) of a selected sensor set 50. The sensor set 50 selected at each instant is chosen from a list of stored sensor sets. Each sensor set comprises one or more navigation sensors 31. The selected sensor set 50 is then the stored sensor set deemed by the flight controller 20 to be the most relevant at the current flight point. Some sensors may be present in one, several, or even all of the possible sensor sets.

[0095] Figure 2 illustrates the process of the invention.

[0096] Each of the navigation sensors 31 emits a signal carrying information relating to weather conditions or the position of the aircraft 1, and for example relating to a saturation contrast (image of brightness),....

[0097] Each of these pieces of information is referenced in a corresponding membership diagram, as with the other criteria, in a so-called "fuzzification" or "blurring" phase. This is achieved using a model comprising, for example, a table or a matrix. or a tesseract of laws or other, the process allows you to choose the sensor or set of sensors to switch to as output.

[0098] This process thus comprises the following steps STP1, STP2, STP3 carried out iteratively.

[0099] Thus, the method includes a step STP1 of determining at least one flight condition parameter varying according to weather conditions or the position of aircraft 1. The flight condition parameter(s) are therefore not related to information relating to the quality of an image.

[0100] Flight condition sensors can be used for this purpose. The control controller 20 then determines the current value of each flight condition parameter by receiving a measurement signal carrying this value, or even by decoding this measurement signal.

[0101] Thus, navigation sensors 31 or other flight condition sensors can also be used for this purpose as a flight condition sensor.

[0102] In flight, the active sensor set can measure one or more flight condition parameters. At startup, if a flight condition parameter is measured by dissimilar sensors distributed across various stored sensor sets, the control controller 20 can request a default sensor set or can use the sensors it deems most suitable according to predetermined criteria.

[0103] Thus, during this STP1 determination step of at least one flight condition parameter, one or more sensors, and where appropriate those of a set of sensors 50 selected in force, each transmit a measurement signal to the control controller 20, this measurement signal carrying a value of the associated flight condition parameter.

[0104] The control controller 20 receives, or rather decodes, each measurement signal received in order to deduce the value of the associated flight condition parameter.

[0105] For example, the process may include at least one of the following measurement steps.

[0106] Therefore, the STP1 determination step of at least one flight condition parameter This may involve measuring the luminance of an aircraft environment. This luminance may be expressed in candelas per square meter or as radiant energy or luminance expressed in watts per square meter per steradian. The luminance may be measured using a luminance meter, for example, whether or not it is part of a sensor suite.

[0107] The STP1 determination step of at least one flight condition parameter may include measuring the light illumination of said environment, for example using the light illumination sensor 40.

[0108] The STP1 determination step of at least one flight condition parameter may include an evaluation of the light intensity of said environment according to a a known method and with known means.

[0109] The STP1 determination step of at least one flight condition parameter may include determining the contrast of an object in said environment against a background. For example, the camera 32 may take a series of images, the control controller 20 analyzing the images to determine said contrast using known techniques.

[0110] The STP1 determination step of at least one flight condition parameter may include measuring a distance between the aircraft 1 and, as shown in [Fig.3], an object 95 in said environment, for example using an obstacle remote sensing system 36, 37, 38.

[0111] According to a particular example, the following measurements are carried out: measurement of a luminous illuminance of an environment of the aircraft 1, determination of a contrast of said environment with respect to a background, and measurement of a distance between the aircraft 1 and an object 95 of said environment.

[0112] In addition, the determination of at least one flight condition parameter may include a step of determining at least one flight parameter of aircraft 1.

[0113] The STP1 determination step of at least one flight condition parameter may then include measuring the speed of movement of the aircraft 1 using a speed measurement system 34, 35.

[0114] The STP1 determination step of at least one flight condition parameter may include the measurement of a pitch angle, for example using an inertial measurement unit.

[0115] Regardless of the various possible combinations, the method includes a step STP2 of selecting a set of sensors 50 which can be described as the selected sensor set from among all the stored sensor sets.

[0116] The selected sensor set 50 is selected by the control controller 20 based at least on the current value of the flight condition parameter(s) according to an onboard selection model.

[0117] For example, the control controller 20 applies a fuzzy logic method during a fuzzy logic selection step.

[0118] This fuzzy logic model includes laws applied by the control controller and providing for each flight condition parameter a level of membership in a category according to the value of that flight condition parameter.

[0119] Figures 4 to 7 illustrate examples for various flight condition parameters through diagrams showing a level of membership on the ordinate and the value of the flight condition parameter on the abscissa.

[0120] In particular, according to [Fig. 4], a flight condition parameter can be a distance from an obstacle. Laws D1, D2, D3, D4 provide an NVD membership level based respectively on the following categories: very short distance, short distance, medium distance and long distance.

[0121] For illustrative purposes, if the measured distance is equal to 80 meters, the control controller determines the presence of a high distance 70% of the time according to law D4 and an average distance 30% of the time according to law D3.

[0122] According to [Fig. 5], a flight condition parameter can be a forward speed. Laws VI, V2, V3 provide an NVV membership level based on the following categories respectively: low speed, medium speed, and high speed.

[0123] According to [Fig. 6], a flight condition parameter can be illumination. Laws E1, E2, E3 provide an NVE membership level based on the following categories respectively: low illumination, medium illumination, and high illumination.

[0124] According to [Fig.7], a flight condition parameter can be a contrast. Laws C1, C2, C3 provide an NVC membership level based on the following categories respectively: low contrast, medium contrast, and high contrast.

[0125] Obviously, other flight condition parameters and / or other categories can be used.

[0126] The fuzzy logic step then includes a step of determining a weighting level for each rule of a plurality of rules.

[0127] In the presence of two flight condition parameters, these rules can be established from a two-criterion decision table. Figure 8 illustrates a two-criterion decision table, crit1 and crit2, each associated with low (Faib), medium (Moy), and high (Elev) values, for selecting the sensor set to use (SI, S2, S3).

[0128] According to the example in [Fig. 8], a first rule may indicate the use of a first set of sensors SI if the first criterion critl is low and the second criterion crit2 is low, or if the first criterion critl is medium and the second criterion crit2 is low, or if the first criterion crit1 is low and the second criterion crit2 is medium. A second rule may indicate the use of a second set of sensors S2 if the first criterion critl is low and the second criterion crit2 is high, or if the first criterion critl is medium and the second criterion crit2 is medium, or if the first criterion critl is high and the second criterion crit2 is low.A third rule may indicate to use a third set of S3 sensors if the first criterion critl is medium and the second criterion crit2 is high, or if the first criterion critl is high and the second criterion crit2 is medium, or if the first criterion critl is high and the second criterion crit2 is high.

[0129] In the presence of three flight condition parameters, these rules can be established at starting from a three-criteria decision cube. Given four flight condition parameters, these rules can be established from a four-criteria decision tesseract...

[0130] According to an illustrative example, a first rule may indicate that a first set of sensors should be used if the forward speed is low, or if the distance is large and the illumination is low, or if the contrast is medium. A second rule may associate a second set of sensors with other combinations.

[0131] Therefore, during an interference step of the fuzzy logic process, the control controller associates each rule with a weighting level calculated from the logical operators and the membership levels.

[0132] During a so-called "defuzzification" step, the control controller 20 selects the set of sensors to be used for control, this set of sensors being the set of sensors associated with the rule having the highest level of weighting.

[0133] For example, a first rule assigns a weighting level of 80% to the first set of sensors, and a second rule assigns a weighting level of 20% to a second set of sensors. The first set of sensors then becomes the sensor set to be used.

[0134] Reference should be made to the literature to understand how to interpret the logical operators "and", "or", and others, and how to apply a fuzzy logic method. For example, an "and" operator may indicate taking the minimum between two values, and an "or" operator is equivalent to taking the maximum between two values.

[0135] With reference to [Fig.2], the selected sensor set emits at least one signal carrying at least one control information.

[0136] The method then includes an STP3 generation step with the control controller 20 of at least one control signal to pilot the aircraft 1, based at least on each piloting information of said at least one piloting information.

[0137] For example, a control signal is transmitted to at least one electronic speed controller 8. For this purpose, the control controller applies one or more control laws providing the control signal(s) based in particular on the control information.

[0138] Figure 3 presents an example intended to illustrate the invention.

[0139] An aircraft 1 is moving through the air to land on a landing area 85. The sky is clear and does not obscure the light emitted by the sun 90.

[0140] However, a building-type object 95 is located near landing area 85. Consequently, the airspace is divided into two zones, namely a lit area ZON1 and a shaded area ZON2 located in the shadow of building 95.

[0141] According to this example, the control controller 20 uses an obstacle remote sensing system 36, 37, 38 to avoid various obstacles according to memorized control laws.

[0142] According to a simple example given for didactic purposes; flight condition parameters include illumination only.

[0143] When aircraft 1 is at the first point PT1, for example, the illumination is in fact high. The flight controller 20 then uses a stored set of sensors having a light-sensitive obstacle detection system 36, 37, 38, such as a RADAR system.

[0144] Consequently, the control controller 20 applies, for example, an algorithm to avoid obstacles based on measurements taken by the RADAR.

[0145] On the other hand, when the aircraft 1 reaches the second point PT2, the light sensor detects low light, the control controller 20 then switches to a set of sensors having a remote sensing system 36, 37, 38 for obstacles operating in the dark, for example a system using an infrared camera.

[0146] Naturally, the present invention is subject to numerous variations in its implementation. Although several embodiments have been described, it is understood that it is not conceivable to exhaustively identify all possible embodiments. It is, of course, conceivable to replace a described means with an equivalent means without departing from the scope of the present invention.

Claims

Demands

1. A method for piloting an aircraft (1) having a suite (30) of sensors comprising a plurality of dissimilar navigation sensors (31), characterized in that the method comprises a piloting phase comprising the following steps: - determination (STP1) of at least one flight condition parameter varying according to meteorological conditions, said at least one flight condition parameter being distinct from information relating to image quality, - selection (STP2) of a set of sensors (50) according to each flight condition parameter of said at least one flight condition parameter according to a selection model carried in said aircraft (1), said set of sensors (50) comprising at least one navigation sensor of said suite (30) of sensors, said set of sensors (50) generating at least one piloting information - generation (STP3) with a control controller (20) of at least one control signal to pilot the aircraft (1),based at least on each piece of pilot information of said at least one piece of pilot information.

2. A method according to claim 1, characterized in that said determination (STP1) of at least one flight condition parameter comprises at least one of the following steps: measurement of a luminance of an environment of the aircraft (1), measurement of a luminous illuminance of said environment, measurement of a luminous intensity of said environment, determination of a contrast of an object of said environment with respect to a background.

3. A method according to any one of claims 1 to 2, characterized in that said determination (STP1) of at least one flight condition parameter comprises the following steps: measurement of a light illumination of an environment of the aircraft (1), determination of a contrast of said environment with respect to a background, and measurement of a distance between the aircraft (1) and an object of said environment.

4. A method according to any one of claims 1 to 3, characterized in that said determination (STP1) of at least one flight condition parameter comprises a step of determining at least one flight parameter of the aircraft (1) or of the position of the aircraft (1), said selection of a set of sensors being made according to said at least one flight parameter or aircraft position (1).

5. Method according to claim 4, characterized in that said at least one flight parameter comprises a speed of movement of the aircraft (1).

6. A method according to any one of claims 1 to 5, characterized in that said selection model applies a fuzzy logic selection step.

7. Method according to claim 6, characterized in that said fuzzy logic selection step comprises the following steps: - determination, for each flight condition parameter of said at least one flight condition parameter, of at least one level of membership in a category associated with that flight condition parameter, - determination of a weighting level for each rule of a plurality of rules, each rule associating a set of sensors comprising at least one navigation sensor from said sensor suite and at least one level of membership in said category, - determination of the sensor set, said sensor set being the set of sensors associated with the rule having the highest weighting level.

8. A method according to any one of claims 1 to 7, characterized in that said at least one flight condition parameter is measured by a plurality of dissimilar sensors of said plurality of navigation sensors, said determination of at least one flight condition parameter is carried out by soliciting the set of sensors in force.

9. Aircraft (1) equipped with a suite of sensors having a plurality of dissimilar navigation sensors (31), characterized in that said aircraft (1) comprises a control controller (20) configured to apply the method according to any one of claims 1 to 8.

10. Aircraft according to claim 9, characterized in that said plurality of navigation sensors comprises at least one of the following: a camera (32) operating in the visible frequency range, a camera (33) operating in the infrared frequency range, a system (34, 35) for measuring the aircraft's airspeed, a system (36, 37, 38) for remote sensing of an obstacle, an ultrasonic positioning system (39), a light illumination sensor (40).

11. Aircraft according to any one of claims 9 to 10, characterized in that said aircraft (1) comprises at least one powered unit (5), said at least one powered unit (5) comprising at least one motor (7) rotating at least one rotor (6), said control controller (20) transmits said at least one control signal to an electronic speed controller (8) of said at least one motor (7).

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