Aircraft comprising a retractable arm equipped with an obstacle detector

The invention relates to an aircraft (5) comprising: a structure (6); a landing gear (1) mounted on the structure (6) of the aircraft; and at least one obstacle detector (2). The aircraft (5) is characterized in that the obstacle detector (2) is secured to an arm (3), said arm (3) being mounted on the structure (6) such that it can move between a rest position in which the arm (3) is retracted and a detection position in which the arm (3) is deployed such that the obstacle detector (2) extends close to a lower portion of the landing gear (1) at a distance from the structure (6) of the aircraft (5).

FIELD OF THE INVENTION

The invention relates to the general field of detection of obstacles around an aircraft.

TECHNICAL BACKGROUND

These days, the main cause of accidents in an airport on traffic lanes and at boarding gates takes place during ground operations of aircraft. These accidents are generally due to collisions of the aircraft with obstacles present around it during its manoeuvres, in particular during backing manoeuvres. In fact, pilots have no visibility in areas located below and behind their aircraft.

The presence of such obstacles is dangerous for ground personnel, for the aircraft as well as for the passengers. Moreover, accidents resulting from the collision of an aircraft with obstacles have the consequence of reducing the operability of the airport, causing delays in flights and strongly perturbing the activities of airline companies.

In order to avoid collisions between an aircraft and obstacles present on the ground, it is known to escort the aircraft during its entire ground operation phase (towing, taxiing, etc.) with dedicated personnel. This personnel, especially trained for this type of assignment, guides the aircraft on the ground while anticipating the presence of obstacles. This guidance, however, the anticipation and the ability to identify possibly interfering obstacles on the runway, are limited by the fact that the personnel is human and can consequently make errors, be momentarily distracted or even have reduced visibility due to meteorological conditions. Moreover, a human being cannot physically view a field of view of 360° around the airplane. Finally, the personnel who assist in parking aircraft and in guiding pilots is required to satisfy radio communication procedures as well as maintain communication by signs with the runway personnel.

In addition, this escorting work is dangerous, tiring and stressing for the ground personnel who, in addition to obstacles present on the ground, must anticipate the movement of vehicles and of other aircraft present on the ground.

Already known, particularly from US2002/0081110, are aircraft conforming to the preamble of claim1.

SUMMARY OF THE INVENTION

One objective of the invention is to propose a new means allowing detection of obstacles during ground operations of aircraft and to respond to the need for visibility rearward and below the aircraft, particularly during backing manoeuvres, which are more effective than conventional techniques, no matter the visibility conditions on the ground, and which in addition are automatic and independent of human reflexes.

To this end, the invention proposes an aircraft comprising:a structure,a landing gear, mounted on the structure of the aircraft, andat least one obstacle detector,
wherein the obstacle detector is attached to an arm, said arm being mounted on the structure so as to be movable between a rest position, in which the arm is collapsed, and a detection position, in which the arm is deployed.

The landing gear is retractable and has a retracted configuration, in which the landing gear is accommodated in a box formed in the structure, and an extended configuration, in which the landing gear is deployed, the arm being mounted in the box of the landing gear, the obstacle detector being located in proximity to a lower portion of the landing gear, distant from the structure of the aircraft, when the arm is deployed.

With such a configuration, the detector is located in immediate proximity to the landing gear. This is particularly advantageous in that the landing gear is the part most exposed to obstacle encounter, (vehicles on the ground in particular) and in that obstacles capable of striking the landing gear are not visible to the crew.

The fact of placing the detection system near the landing gear makes it possible to see what is in the direction of movement of the landing gear, avoids any parallax problems and thus allows detection of obstacles and the possibility of classifying them simply as critical or non-critical (binary test of the “is the obstacle in the movement axis of the airplane at the undercarriage level or not?” type).

Any other positioning in the fuselage or on the wings (outside the vicinity of the undercarriage) imposes a more complex evaluation (evaluation of the reciprocal positioning between the obstacle and the landing gear), which cannot be carried out with a single sensor (determination of both a direction and a distance to the landing gear for any potential obstacle is necessary).

Certain preferred but not limiting features of the aircraft are the following:the obstacle detector can be attached in an area at the back of the box;the landing gear comprises a casing, having a main direction extending along a longitudinal axis, said casing comprising a first end configured to be mounted on the aircraft, and a second end opposite to the first end, and a rod, slidably mounted on the second end of the casing, said rod being movable in translation with respect to the casing along the longitudinal axis, and, in the rest position, the obstacle detector extends in an area adjacent to the second end of the casing,the arm comprises a first end, mounted on the structure, and a second end, opposite to the first end, the obstacle detector being attached in an area adjacent to the second end of the arm,the obstacle detector is attached so as to be oriented toward a rear area of the landing gear,the arm passes from the rest position to the detection position only when the landing gear is in the extended configuration,the arm passes into the rest position when a movement speed of the aircraft is lower than a predetermined threshold speed,the arm is telescoping,the aircraft comprises at least two obstacle detectors,the obstacle detectors are attached together so as to form a single part,the obstacle detector comprises at least one, preferably at least two obstacle detectors selected from the following group: infrared proximity detector, microwave proximity detector, ultrasonic proximity detector, one or more infrared or visible cameras, an ultrasonic range finder, a radar range finder or a laser range finder,the aircraft further comprises an actuator configured for rotating the obstacle detector around the arm,the actuator is configured for rotating the arm the obstacle detector around the arm by rotating the arm,the obstacle detector comprises a detection field having an aperture and a depth configured to cover a lower area of the aircraft and a rear area of the aircraft,the aperture of the detection field has a horizontal viewing angle comprised between 0° and 270°, and a depth comprised between approximately 0 meter and approximately 250 meters,the aircraft comprises at least two obstacle detectors, each obstacle detector being attached to a respective arm mounted on the structure so as to be movable between a rest position and a detection position.

DETAILED DESCRIPTION OF ONE EMBODIMENT

In order to allow optimized obstacle detection and reduce the risks of collision of an aircraft5during operations on the ground, the invention proposes to equip the aircraft5with one or more obstacle detectors2on its undercarriage1(or landing gear). The obstacles thus detected by the detector(s) can then be used as input values for dedicated processing units (or if appropriate directly to the pilot of the aircraft), configured to analyze these input values and to deduce from them a safe and optimized trajectory during movement on the ground of the aircraft. For example, the processing units can prepare a map of the obstacles present around the aircraft so as to help the pilot of the aircraft to direct the aircraft. In appropriate, the processing units are also configured to process information obtained by the obstacle detectors and to optimize them (for example, when the detector2comprises a video camera, the images obtained need to be processed in order to take into account the differences in lighting between shadow areas and areas exposed to light).

The landing gear1can also comprise a main landing gear (for example located under the wings) or even an auxiliary landing gear (such as a nose landing gear, located at the nose of the aircraft5). In the example illustrated in the figures, this is a main landing gear.

A landing gear1can be fixed or retractable into a dedicated landing gear1box7formed in the structure6(fuselage or wings) of the aircraft5.

Hereafter, the invention will be described more particularly in the case of a retractable landing gear1, i.e. a landing gear1configured to be retracted between the takeoff phase and the landing phase into a landing gear1box7of an aircraft5, and extended during the landing phases and ground operations.

The landing gear1generally comprises, in a manner known per se, a casing10, having a main direction extending along a longitudinal axis X, which constitutes the main body of the landing gear1and allows transmission of the main forces to the structure6of the aircraft5. The casing10comprises, to this end, a first end10a, mounted on the structure6of the aircraft5, and a second end10b, comprising a cavity that is not visible in which is pivotally mounted a lower portion consisting of a base12and a sliding rod14.

The sliding rod14is movable in translation with respect to the casing10along the longitudinal axis X and forms, with the base12, a damper adapted to absorb the energy of impact in landing and support the ground manoeuvres of the aircraft5. The base12can be mounted in the cavity of the second end10bof the casing10so that the sliding rod14can pivot substantially around the longitudinal axis X of the casing10.

The end14bof the sliding rod14, which is farther from the second end10bof the casing10, supports displacement means16, such as for example a wheel consisting of a rim.

The landing gear1further comprises a brace-strut18, comprising a first end configured to be mounted on the aircraft5and a second end configured to be connected to the casing10, in proximity to the second end10bof said casing10. The brace-strut18is configured to transmit to the structure6of the aircraft5the axial loads coming from the displacement means16.

The applicant became aware that it was technically difficult to accommodate sensors such as obstacle detectors2on the landing gear1, in that the detection field F of these obstacle detectors2must cover at least the area extending below the aircraft5and the area extending to the rear of the aircraft5(in the direction of the tailplane and beyond). Optionally, it can also be useful for the obstacle detectors2to be capable of covering the forward area (toward the nose) of the aircraft5.

Moreover, the performance of the obstacle detectors2must not be impaired due to hitting an object when the aircraft is rolling at high speed on the runway, or due to meteorological conditions (snowflakes, raindrops, hail, etc.) or particles present in the environment (dust, smoke, pollution, etc.).

It will also be noted that the position, the orientation and the selection of the obstacle detectors2must take into account the extent of the area that it is desired to monitor, the intrinsic detection field of the selected obstacle detector (aperture and depth of field), as well as the sensitivity of each detector (to lighting in particular, which is generally lower below the aircraft than around it, which can cause problems for some types of detectors).

These difficulties are further increased due to the retractable nature of the landing gear1. In fact, in the extended configuration of the landing gear1, the obstacle detectors2must be oriented in the direction for detecting obstacles. In addition, in the retracted configuration, the obstacle detectors2must be able to be accommodated in the structure6of the aircraft5, the available volume whereof is sharply limited.

So as to meet all the requirements cited above, the obstacle detector2is attached to an arm3, mounted on the structure6of the aircraft, which is movable between a rest position in which it is collapsed, and a detection position, in which it is deployed so as to position the obstacle detector2in the lower portion of the landing gear1, at a distance from the structure6of the aircraft5and from the ground. In the detection position, the obstacle detector2then extends into an area adjacent to the second end10bof the casing10, which makes it possible to obtain a large detection field F. In fact, by positioning the obstacle detector2in this manner, the detection field F of the detector2is not hindered by the structure6(fuselage or wing, depending on the position of the detector2) of the aircraft5. In addition, the obstacle detector2being at a distance from the ground, its detection field F is not limited by the presence of the ground and the risk that it may enter into collision with objects present on the ground or projected during movement of the aircraft5are strongly reduced.

The obstacle detector2can be started so as to detect the presence of possible obstacles around the aircraft5when the arm3is in the detection position, and shut down when the arm3is in the rest position.

The arm3has a main body30, extending in a main direction defining a longitudinal axis Y of the arm3and comprising a first end30a, configured to be mounted on the structure6of the aircraft, and a second end30b, opposite to the first end30a.

In the detection position, the body of the arm3can extend substantially vertically, i.e. in the direction of the ground and substantially parallel to the longitudinal axis X of the casing10. The obstacle detector2can then be attached at the second end30bof the arm3, so as to extend below the body30of the arm3when it is in its detection position.

The arm3can be telescoping, so that the distance between the first30aand the second30bend of the body30of the arm3is variable. In this embodiment, the rest position of the telescoping arm3then corresponds to a retracted position, while its detection position corresponds to a deployed position. The distance between the first30aand the second30bend is therefore shorter in the rest position than in the collapsed position of the telescoping arm3.

As a variant, the arm3can be pivoting and be rotatably mounted at its first end30aon the structure6of the aircraft5using a pivoting type attachment. In this alternative embodiment, the distance between the first30aand the second30bend of the arm3is therefore fixed. Moreover, in the rest position of the pivoting arm3, the arm3can be in a substantially horizontal position, then move to a substantially vertical position in the detection position by rotation around the pivot link.

According to yet another variant, the arm3can be both telescoping and pivoting.

The arm3can be mounted on the aircraft5, in the box7of the landing gear1.

The arm3can then be collapsed into the box7of the landing gear1when it is in the rest position and deploy when the landing gear1is in its extended configuration so as to come into the detection position.

The box7of the landing gear1then makes it possible to protect the arm3and the obstacle detector2, in particular during flight phases. This configuration further makes it possible to not affect the aerodynamic properties of the aircraft5when the arm is in its rest position.

The position of the arm3in the box7can in particular be selected according to the accuracy of detection and the detection field F of the obstacle detector2as well as the geometry of the landing gear1and of its landing box7(space available in the box7, kinematics of extension and retraction, etc.). It can in particular be advantageous to offset the arm3toward the back of the box7(i.e. as close as possible to the tailplane of the aircraft5) so as to optimize the detection field F of the detector2, in particular when it is desired to visualize, using the detector the underside and rear areas of the aircraft5, and to reduce the areas masked off (in particular by the presence of the landing gear1). In addition, the position of the arm3in the box7is selected so that the arm does not interfere during extension or retraction of the landing gear1into the box7. Thus, the first end of the arm3can for example be positioned in the area extending between the wheel and the brace-strut of the landing gear1when the landing gear is retracted into the box7.

The position of the obstacle detector2on the arm3can also be determined depending on the accuracy of detection and of the detection field F of the obstacle detector2, as well as the geometry of the landing gear1and the position of the arm3in the landing box7.

In one embodiment, the arm3moves from its rest position to its detection position only when the landing gear1is in its extended configuration. The arm3thus remains collapsed in the rest position and protects the obstacle detector2as long as the landing gear1is in the retracted configuration.

Optionally, the arm3can be controlled by the speed of movement of the aircraft5, to avoid the obstacle detector2being struck by an object, for example an object present on the runway, or meteorological conditions (rain, snow, etc) hampering the detection of obstacles by the detector2. In this alternative embodiment, the arm3can enter its detection position only when the following two cumulative conditions are satisfied:The landing gear1is in its extended configuration, andThe speed of the aircraft5is less than a predetermined threshold speed.

These cumulative conditions thus allow protecting the obstacle detector2and not prematurely deploying the arm3.

When appropriate, the obstacle detector2can also be protected from its environment (bad weather, wind, etc.) using a protective shield, for example by a protective cap or by the support3of the detector2.

The aircraft5can further comprise a control unit, adapted to control the arm3and the obstacle detector2. In particular, the control unit can be configured to cause the arm3to move from its rest position to its detection position when the corresponding condition(s) (extended configuration of the landing gear and, if appropriate, speed of the aircraft5less than the predetermined threshold speed) are satisfied. Moreover, the control unit can control starting (respectively extinction) of the obstacle detector2when the arm3is in its detection position (respective rest position).

The control unit can in particular be accommodated directly in the arm3, for example in the body30of the arm3. Moreover, the arm3can be equipped with the set of connection and power supply cables of the detector(s). In this manner, it is sufficient to attach the arm3to the structure6of the aircraft and to connect the cables of the detectors to the existing array of cables of the aircraft5to install the arm3and the obstacle detector2.

The control unit can further be configured to transmit information collected by the obstacle detector2to the dedicated processing units, so as to define a safe and optimized trajectory during ground movements of the aircraft5.

According to one embodiment, the landing gear1can comprise several obstacle detectors2, for example two obstacle detectors2, so as to improve the detection of obstacles, reduce the noise which can be caused by external conditions (particularly by meteorological conditions) and compensate for any possible malfunction of one of the obstacle detectors2. The two obstacle detectors2can then be identical (same detection technology and/or same detection accuracy) or different.

For example, the landing gear1can comprise at least one, preferably two obstacle detectors2selected from the following group: a proximity detector (infrared, microwave, ultrasound, etc.), one or more cameras (infrared or visible—single or stereo artificial vision, etc.), a range finder (ultrasonic, radar or laser range finder), etc.

In the case of an obstacle detector2comprising a camera, the images transmitted by the camera can further contribute to the collection of information which can help in guiding or piloting the aircraft5, with registering the position of the aircraft5with respect to marks on the ground or to panels placed on the edges of the traffic routes, etc.

The aircraft5can further comprise several arms3, each equipped with at least one obstacle detector2. For example, the aircraft5can comprise a first arm3mounted in proximity to a main landing gear1and to which are attached one or more obstacle detectors2, and a second arm3mounted in proximity to an auxiliary landing gear1and to which are attached one or more obstacle detectors2.

The implementation of several arms3for attaching obstacle detectors makes it possible to obtain several distinct viewpoints and thus to enlarge the obstacle detection field, to improve the accuracy of measurements carried out by the different obstacle detectors and to reduce possible blind spots as well as the impact of meteorological conditions on the measurements carried out.

For example, an example of positioning of an arm3equipped with obstacle detectors2is illustrated inFIG. 6, on an example of an aircraft5comprising two main landing gear1aattached at its wings and a nose landing gear1battached under the nose of the aircraft5. It will be understood that the invention is not limited to this type of aircraft, and can just as well apply to aircrafts5comprising a different number of landing gears1. The position and the orientation of the arms3and of the obstacle detectors2are then adapted depending on the type of aircraft5and the number of landing gears.

In this exemplary embodiment, the arms3are attached to a rear portion of the box7of the main landing gears1a, their respective detectors2being oriented toward the rear of the aircraft5. Here the aircraft5does not comprise an obstacle detector2at its nose landing gear1b. It will of course be understood that the aircraft could, as a variant, comprise a supplementary arm attached in the box7of the nose landing gear1b. Thanks to this position and to this orientation, not only can the obstacle detectors2be accommodated in a free space in the box7of their respective landing gear1awhile still observing the kinematics of the landing gear1aduring its extension or its retraction, but in addition the detection field F of the detectors2allows coverage of an important portion of the area extending below the aircraft5and behind it. Moreover, this position of the obstacle detectors2allows obtaining considerable coverage of their respective detection field F in the area subjacent to the aircraft5.

The obstacle detector2is preferably selected so as to have an optimum detection field F for a small dimension, so as to obtain good detection performance and to reduce the use of space of the arm3, in particular when the arm3is collapsed in the rest position. It is then unnecessary to modify the structure6of the aircraft5to receive the collapsed arm3, particularly when the arm3is accommodated in the box7of the landing gear1.

Preferably, the obstacle detector2is selected so as to have a detection field F capable of covering a lower area and a rear area of the aircraft5. For example, the aperture of the detection field can have an angle α comprised between 0° and 270°, and a depth comprised between approximately 0 meter and approximately 250 meters. Such a detector2is then capable of detecting with sufficient accuracy obstacles in the environment of an aircraft5. Moreover, current technology makes it possible to make obstacle detectors2having such performance with small size.

In one embodiment, the landing gear1can comprise and actuator4configured to rotate the obstacle detector2around the longitudinal axis Y of the arm3. The implementation of such an actuator4thus allows the detector2to enlarge the angle α of its detection field F by performing a sweep of the surrounding area. The detector2can thus detect obstacles over 360° around the longitudinal axis Y of the arm3, even if the initial range a of the detection field F of the obstacle detector2is less than 360°.

The actuator4thus allows a reduction in the dimensions of the obstacle detector2, and therefore its bulk, by reducing the detection field required for the detector2.

According to a first embodiment, the actuator4can be configured to rotate the obstacle detector2around the axis Y of the arm3, the arm3remaining fixed with respect to the structure6of the aircraft5.

As a variant, according to a second embodiment, the actuator4can rotate the arm3around its longitudinal axis Y, the obstacle detector2remaining fixed with respect to said arm3.

When the landing gear1comprises several obstacle detectors2, at least two obstacle detectors2can be attached together so as to form a single part. For example, all or part of the obstacle detectors2can be attached by means of a common support.

As a variant, the obstacle detectors2can be attached separately to the arm3. If appropriate, each obstacle detector2can be associated with a corresponding actuator4. The obstacle detectors2can then be set into motion independently from one another by means of their respective actuator4.

The attachment of the obstacle detectors2to a collapsible arm3makes it possible to guarantee the proper positioning of the obstacle detectors2, even if the landing gear1is retractable. The position of the obstacle detectors2is in fact independent of that of the landing gear1. Moreover, the optional presence of actuators4allow the obstacle detectors2to sweep a large detection field F, and to guarantee complete vision forward, rearward and to the sides of the aircraft5.

In addition, the addition of an arm3requires only minimal modifications of the structure6of known aircrafts5. The control unit and the connection and power supply cables of the detector(s) can in fact be accommodated in the arm3. It is therefore easy to upgrade existing aircrafts5so as to equip them with obstacle detectors2.