Aircraft moving surface monitoring system

Abstract

One aspect of the invention relates to a monitoring system comprising a movable surface of an aircraft. The monitoring system according to the invention also includes an actuation system for the movable surface of an aircraft comprising actuators. The monitoring system according to the invention comprises at least two position sensors, a first position sensor of the at least two position sensors being adapted to measure the position of a first actuator among the actuators, and a second position sensor of the at least two position sensors being adapted to measure the position of a second actuator among the actuators.The monitoring system includes at least two force sensors. One of these two force sensors is adapted to measure forces acting on the first actuator, and the other is adapted to measure forces acting on the second actuator. The monitoring system also includes a computer configured to detect misalignment of the moving surface and excessive force acting on the first and / or second actuator, based on the position obtained from the two position sensors and the force measured by the two force sensors.

Description

Title of the invention: System for monitoring a moving surface of an aircraft TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of systems for monitoring the moving surfaces of an aircraft.

[0002] The present invention relates to a system for monitoring a moving surface of an aircraft and a method for monitoring a moving surface of an aircraft. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] The moving surfaces of an aircraft are mechanical parts whose inclination and position relative to another reference part of the aircraft can vary. [Fig. 1] schematically shows a system 100 comprising a moving surface 101 and a reference mechanical part 102. [Fig. 2] schematically shows the same moving surface 101 with an inclination value relative to the reference mechanical part 102 different from the inclination value relative to the reference mechanical part 102 shown in [Fig. 1]. For the sake of simplicity, we will now use the term "surface inclination" to describe the inclination of a moving surface relative to a reference part of the aircraft.

[0004] The inclination of a surface is modified by an actuation system comprising one or more actuators. Thus, as shown in Figures 1 and 2, an actuator 103 allows a modification of the inclination of the surface 201 by performing a movement. The actuator 103 is fixed to the reference mechanical part 102 by a fixing 106 and to the movable surface 101 by a fixing 107. The movable surface 101 is fixed to the reference mechanical part 102 by a fixing 105. The inclination of the surface is also commonly called the position of the surface. Indeed, the position of the edge of the surface located opposite the edge of the surface fixed to the aircraft is modified when the inclination of the movable surface changes. It should be noted that the position is relative to a reference part of the aircraft. For example, in Figures 1 and 2, the position of the edge 104 of the surface 101 has been modified relative to the reference mechanical part 102.For the sake of simplicity, we will now use the term "surface position" to describe the position of the moving surface relative to another reference part of the aircraft.

[0005] The moving surfaces are for example the flaps of an aircraft wing, the leading edge slats or the spoilers of an aircraft wing.

[0006] When a surface is movable using at least two actuators, there is a risk of skew of the movable surface. Skew of a movable surface can also consist of warping of the movable surface. This skew, if too great, can damage the structure of the aircraft, in particular the actuation system of the movable surface, and thus compromise its mission. It is therefore important to be able to monitor movable surfaces in order, in particular, to detect skew of a movable surface.

[0007] Current monitoring systems for moving surfaces are based on measurements of the position of said surface. It should be noted that such monitoring systems must be capable of measuring the inclination of the surface relative to a reference mechanical part of the aircraft, such as, for example, the frame of an aircraft wing when monitoring an aircraft wing flap. Indeed, measuring the inclination of the surface relative to a reference part allows the detection of a crosswise movement of the surface. Monitoring only the position of the actuator is not sufficient because it would not be possible, for example, to detect a possible crosswise movement of the tilting surface following a mechanical breakage between the actuator and the tilting surface.

[0008] Monitoring systems are currently implemented via “wire” sensor-based systems or by articulated mechanical systems.

[0009] When a system based on "wire" sensors is used, the metal cable of each sensor connects the moving surface to the reference mechanical part. Thus, when the moving surface is tilted, the cables are unwound (or wound) and thus each drive a rotating axis. A rotating cable sensor can then be used to deduce the tilt of the moving surface.

[0010] In the case of an articulated mechanical system, the sensor is no longer driven via a cable but via a connecting rod or crank system connected to the moving surface.

[0011] A crossing of a moving surface is therefore detected by such systems when a difference in position is measured between the different sensors of said surface.

[0012] An example of a system comprising moving surfaces, a system for actuating the moving surfaces and a system for monitoring the moving surfaces is presented in [Fig. 3]: a power generator 3 generates a torque via an electric or hydraulic motor, controlled by a computer. The torque is then transmitted to the actuators 4a and 4b of the moving surfaces 10 and 11, represented here by ball screws, by mechanical transmission elements 5. The position of the moving surfaces 10 and 11 is measured by the position sensors 1. The two ball screws 4 then transform the torque into translation and transmit this translation to the two moving surfaces 10 and 11

[0013] The four position sensors 1 of the monitoring system therefore make it possible to monitor the position of the surfaces 10 and 11.

[0014] The crossing of a moving surface can occur in two cases: • Damage to a mechanical transmission element; or • Damage to an actuator or the actuator's attachment to the moving surface.

[0015] [Fig.4] illustrates the damage 20 of a mechanical transmission element 5 and [Fig.5] the damage 21 of an actuator 4b or of the fixing of an actuator 4b with the mobile surface 10. These two damages will cause the mobile surface 10 to be placed across. This positioning will be detected since a difference in position will be measured using the two sensors 1 of the mobile surface 10.

[0016] When a crossing of a moving surface is detected, a stop of the actuation system is carried out. This stop may consist of an immobilization of the actuators or a modification of the position of the surface making it possible to reduce the force transmitted by the actuators of said surface.

[0017] Current systems including a monitoring system implemented via “wire” sensor-based systems or by articulated mechanical systems, however, present several problems.

[0018] A first problem with such systems is the difficulty of ensuring accurate detection of the crossing of a moving surface of an aircraft regardless of the operating temperature of the system. Indeed, monitoring systems, which are based on measuring the position of the moving surface to detect a crossing of the moving surface, do not allow for ensuring accuracy in measuring the position of the surface regardless of the operating temperature of the system. Indeed, once the moving surface is deployed, thermal expansions and / or contractions can cause parasitic rotations of the sensors and thus degrade the accuracy of the measurement. In addition, when the distances to be measured between the reference part and the moving surface are significant, the accuracy of the measurement varies further depending on the operating temperatures of said system.

[0019] A second problem with current monitoring systems is their sensitivity to environmental pollution. Indeed, the sensors of such systems are exposed to the flow of outside air, in particular during an extension of the monitored mobile surface. An example of such an extension of a tilting surface 201 is presented in [Fig.2].

[0020] In the case of connecting rod or crank type monitoring systems, two other problems arise. First of all, these systems are bulky and can therefore lead to strong integration constraints given the generally very limited space under the moving surface, for example between the wing frame and the flap. In addition, these systems are heavy and include a significant number of mechanical elements to be considered in the transmission chain

[0021] Furthermore, it is important to ensure the integrity of the actuation system, and in particular of the actuators, by limiting the force transmitted through said actuators. Currently, it is common to use a mechanical torque limiter such as a ball limiter to limit the force transmitted through said actuators. [Fig. 3] schematically shows ball limiters 2a and 2b. Thus, the element 3 generates a torque. This torque is transmitted to the mechanical transmission elements 5 and to the torque limiters 2a. The torque is then transmitted to the first actuators 4a. Finally, the torque is subsequently transmitted via the mechanical transmission elements 5 to the second torque limiters 2b and to the external actuators 4b.

[0022] These mechanical torque limiters, in particular ball limiters, have several disadvantages such as their sensitivity to vibration conditions, the risk of untimely triggering or the difficulty of guaranteeing constant precision over the entire operating temperature range of such a system. In addition, these torque limiters risk integrating dormant failures into the actuation system. A dormant failure is a failure that is not detected when it occurs and which has no impact on the operation of the aircraft if it occurs alone. For example, in the case of torque limiters 2a and 2b of [Fig. 3], a failure of a torque limiter can only be detected if there is a need to limit the torque, possibly well after the occurrence of the failure at the torque limiter and therefore the absence of limitation by the torque limiter.

[0023] The following documents are known from the state of the art: • US 9108724 B2 entitled “Adjustment System of an airplane with an adjustable flap”, • FR 2983456 Al entitled “System for actuating an aircraft control surface, and associated method”, and • US 8583293 B2 entitled “Flight control surface actuation force fight mitigation System and method”.

[0024] The invention therefore aims to provide a system ensuring the integrity of the actuation system which does not have the drawbacks mentioned above. Summary of the invention

[0025] The invention offers a solution to the problems mentioned above, by allowing reliable detection of a crossing of the moving surface and of an over-force passing through one or more of the actuators of the moving surface.

[0026] One aspect of the invention relates to a monitoring system comprising: • a moving surface of an aircraft; • an actuation system for the moving surface of the aircraft comprising actuators; • At least two position sensors per moving surface of the aircraft, a first position sensor among the at least two position sensors being adapted to measure a position of a first actuator among the actuators and a second position sensor among the at least two position sensors being adapted to measure a position of a second actuator among the actuators; • At least two force sensors per moving surface of the aircraft, a first force sensor among the at least two force sensors being adapted to measure forces passing through the first actuator among the actuators and a second force sensor among the at least two force sensors being adapted to measure forces passing through the second actuator among the actuators; and • A computer configured to detect a crossing of the moving surface and an excess force passing through the first and / or the second actuator from the position obtained by the at least two position sensors and the force measured by the at least two force sensors.

[0027] This monitoring system allows reliable detection of a crossing of the moving surface or of an over-force passing through one of the actuators of the moving surface. This monitoring system has the particular advantage of using position sensors measuring the position of an actuator and not the position of the moving surface. Thus, the position sensor has a simplified architecture because it has no direct link with the moving surface. The position sensors compatible with the invention only require a direct connection to an actuator or using a simple reducer to fix it to an actuator. In addition, the position sensor for measuring the position of the actuator can be placed so as to be less subject to environmental aggressions than a position sensor measuring the position of a moving surface.

[0028] The position sensors used in the monitoring system according to the invention measure the movements of the actuators and therefore make it possible to detect cases of a moving surface being placed across when one or more actuators of the actuation system exert a thrust unequal to the thrusts of the other actuators of the actuation system. They also make it possible to detect the positioning of a moving surface across in the event of a problem linked to the operation of the aircraft, such as example a mechanical transmission failure, as illustrated in [Fig.4] or a seizure at the level of a slide or a hinge or at the level of an actuator.

[0029] The monitoring system also includes force sensors measuring the forces passing through at least two actuators of the actuation system. These force sensors make it possible to manage the case of a moving surface being placed across due to damage to an actuator or a snagging of the moving surface. Indeed, these force sensors make it possible to detect the absence of force passing through one of the actuators of the actuation system and therefore to detect an abnormal case or an excessively large difference in force between the actuators of the same actuation system. The force sensors also offer the advantage of being modular. Indeed, the threshold is managed electronically and is therefore easily configurable. Thus, with the same force sensor, it is possible to protect several types of actuators. In addition, compared to mechanical limiters, the force sensors offer the possibility of being tested regularly.It is thus possible to check at any time that these force sensors do not present any anomalies. Finally, these sensors can be used in preventive maintenance logic. For example, it will be possible to monitor the evolution of the forces passing through the actuators during similar missions of the aircraft. If these forces vary significantly, it will be possible to anticipate maintenance operations to prevent seizure of the actuator and / or the moving surface for example.

[0030] In addition to the characteristics which have just been mentioned in the preceding paragraph, the monitoring system according to one aspect of the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations: • the moving surface is a flap of an aircraft wing or a leading edge slat of an aircraft or a lift spoiler. • the at least two position sensors are variable differential transducers or resolvers or potentiometers. • the at least two force sensors are strain gauges or deformation gauges or electromagnetic sensors. • the first and second actuators among the actuators of the actuation system are located at the ends of the moving surface.

[0031] A second aspect of the invention relates to a first monitoring method implemented by the monitoring system according to the invention, the first method comprising: • Measuring the position of a first actuator and a second actuator among the actuators of the actuation system by the at least two position sensors of the monitoring system; • Measure the forces passing through the first actuator and the second actuator among the actuators of the actuation system by the at least two force sensors of the monitoring system; • Receive, by the calculator, the positions measured by the at least two position sensors and the forces measured by the at least two force sensors; • Calculate, by the calculator, the absolute value of a maximum difference between the positions measured by the at least two position sensors; • Calculate, using the calculator, the absolute value of a maximum difference between the measured forces passing through the at least two force sensors; and • Detect a crossing of the moving surface if: • the absolute value of the maximum difference between the positions measured by the at least two position sensors is greater than a threshold distance value difference; or • the absolute value of the maximum difference between the measured forces passing through the at least two force sensors is greater than a threshold force difference value.

[0032] In addition to the characteristics which have just been mentioned in the preceding paragraph, the first method according to one aspect of the invention may have an additional step of stopping the system for actuating the mobile surface when a crossing of the surface is detected.

[0033] A third aspect of the invention relates to a second monitoring method implemented by the monitoring system according to the invention, the second method comprising: • Measure the forces passing through the actuators by the at least two force sensors of the monitoring system; • Receive, by the calculator, the forces measured by the at least two force sensors; • Determine, by the calculator, the maximum absolute value of a force passing through an actuator among the forces measured by the at least two force sensors; and • Detect an excess force passing through the actuator among the actuators of the moving surface if the maximum absolute value of the force passing through the actuator among the forces measured by the at least two force sensors is greater than a threshold force value.

[0034] In addition to the characteristics which have just been mentioned in the preceding paragraph, the second method according to one aspect of the invention may have an additional step stopping the moving surface actuation system when an over-force passing through an actuator among the actuators of the moving surface is detected.

[0035] A fourth aspect of the invention relates to an aircraft comprising the surveillance system according to the invention.

[0036] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0037] The figures are presented for information purposes only and in no way limit the invention. • [Fig.l] and [Fig.2] show a schematic representation of a system 100 according to the prior art comprising a moving surface, an actuator and a reference mechanical part. • [Fig.3] shows a schematic representation of a system according to the prior art comprising moving surfaces, a system for actuating the moving surfaces and a system for monitoring the moving surfaces. • [Fig.4] and [Fig.5] show a schematic representation of a damage to a system according to the prior art comprising moving surfaces, a system for actuating the moving surfaces and a system for monitoring the moving surfaces. • [Fig.6], [Fig.7] and [Fig.8] show different schematic representations of a monitoring system 600 according to the invention. • [Fig.9] shows a schematic representation of a first monitoring method 800 according to the invention. • [Fig. 10] shows a schematic representation of a second monitoring method 900 according to the invention. DETAILED DESCRIPTION

[0038] The figures are presented for information purposes only and in no way limit the invention.

[0039] [Fig.6] shows a schematic representation of the monitoring system according to the invention.

[0040] The monitoring system 600 comprises a moving surface 10 or 11 of an aircraft, an actuation system comprising actuators 4, at least two position sensors 7 for each moving surface 10 and 11, at least two force sensors 6 for each moving surface 10 and 11 and a computer. It should be noted that [Fig. 6] also presents, for the sake of clarity, elements which are not included in the monitoring system 600 according to the invention. Thus, a power generator 3 and transmission elements 5 are presented in [Fig. 6] but are not included in the monitoring system 600 according to the invention. The computer(s) of the monitoring system are not shown in the various figures.

[0041] In a variant of the invention, the movable surface 10 or 11 is a tilting surface such as, for example, a flap of an aircraft wing or a leading edge slat of an aircraft or a lift destroyer.

[0042] The monitoring system according to the invention comprises at least two position sensors 7 for each moving surface 10 and 11. Each position sensor 7 makes it possible to measure the position of a separate actuator 4 among the actuators of the system for actuating the moving surface. The position of an actuator is measured in millimeters, centimeters or meters. It may, for example, correspond to the distance between the ends of the actuator. The value of the position of an actuator makes it possible to calculate the position and / or the inclination of the moving surface.

[0043] In a variant of the invention, compatible with the previous variant, the position sensors 7 are variable differential transducers or resolvers or potentiometers.

[0044] When the actuation system of a moving surface 10 or 11 comprises two actuators 4, each actuator 4 will have its position measured by a different position sensor 7. For example, in [Fig. 6], for the moving surface 10, the actuation system comprises two actuators 4. The monitoring system comprises two position sensors 7, each of the position sensors 7 being adapted to measure the position of a separate actuator 4.

[0045] When the system for actuating a mobile surface comprises more than two actuators, two variants of the monitoring system according to the invention, compatible with the previous variants, are possible.

[0046] The first possible variant consists of measuring the position of all the actuators. Thus there will be as many position sensors as there are actuators. [Fig.7] shows for example a monitoring system according to the invention comprising three actuators 4 and three position sensors 7 per moving surface 10 or 11.

[0047] The second possible variant consists of measuring the position of only certain actuators among all the actuators of the actuation system. Thus there will be fewer position sensors than actuators. When this second implementation is chosen, it is necessary for the position sensors to measure the position of the actuators located at the ends of the moving surface. Thus in [Fig.7], among the three actuators 4 of the actuation system of the moving surface 10 or 11, the position of the actuator 4 located between the other two actuators 4 would not be measured by a position sensor. For the sake of understanding, a zone 12 delimited by dotted lines has been added for each moving surface 10 and 11. The actuator in the central position whose position is not measured is the one included in this zone 12. Thus, in this second mode of implementation, one or more actuators of the actuation system do not have their position measured. This second implementation mode therefore requires fewer position sensors than actuators. It should be noted that this implementation mode does not exclude the measurement of the position of one or more actuators, located between the actuators located at the ends of a moving surface, being carried out by a position sensor.

[0048] This second variant ensures the protection of the actuation system of a moving surface when a mechanical transmission element 5 is damaged since the crossing of the moving surface will be detected using the position measurements of the at least two position sensors 7 which measure the positions of the actuators 4 located at the ends of the moving surface 10 or 11.

[0049] The monitoring system according to the invention comprises at least two force sensors 6 for each moving surface 10 and 11. Each force sensor 6 makes it possible to measure the forces passing through a separate actuator 4 among the actuators of the system for actuating the moving surface. In one example, the actuators 4 whose forces are measured are identical to the actuators 4 whose position is measured by the position sensors 7. Thus, in this example, for a monitoring system comprising N position sensors 7 measuring the position of N actuators 4, the monitoring system will also comprise N force sensors 6 which will measure the forces passing through these same N actuators 4. A monitoring system comprising more than two position sensors and more than two force sensors makes it possible to have redundancy at the measurement level.

[0050] In a variant of the invention, compatible with the previous variants, the force sensors 6 are strain gauges or deformation gauges or electromagnetic sensors.

[0051] The monitoring system finally comprises a computer. The computer is an electronic system performing calculations on command. The computer is configured to detect a crossing of the moving surface and an excess force passing through the first and / or the second actuator from the position obtained by the at least two position sensors and the force measured by the at least two force sensors. The computer of a monitoring system of a moving surface is therefore connected with the position sensors and the force sensors of said monitoring system in order to be able to receive the measurements made and optionally store them. The computer is also adapted to allow the stopping of the actuation system dedicated to said moving surface when a crossing of said moving surface and / or an excess force passing through the first and / or the second actuator has been detected.This shutdown of the actuation system ensures its integrity.

[0052] [Fig.8] is a schematic representation of the monitoring system 600 according to the invention when it is used on a so-called distributed architecture of a system without mechanical link between the two moving surfaces 10 and 11. The variants of the monitoring system 600 are also compatible with these so-called distributed architectures.

[0053] The invention also relates to a method 800 implemented by the monitoring system 600 according to the invention or by one of the variants of the monitoring system 600 according to the invention. [Fig.9] is a schematic representation of the method 800.

[0054] The method 800 comprises a first step 810 of measuring the position of a first actuator and a second actuator among the actuators of the actuation system by the at least two position sensors of the monitoring system. The position of an actuator is expressed in millimeters, centimeters or meters.

[0055] In a variant of the method 800, the position of more than two actuators of a moving surface are measured in step 810. In a first example, the position of all the actuators of a moving surface is measured in step 810. In a second example, only the position of certain actuators among all the actuators of a moving surface is measured in step 810. For this second example, it is necessary that at least the position of the actuators located at the ends of the moving surface be measured, the measurement of the position of the other actuators being optional.

[0056] The method 800 comprises a second step 820 of measuring the forces passing through the first actuator and the second actuator among the actuators of the actuation system by the at least two force sensors of the monitoring system. A force is expressed in Newtons. The force sensors are therefore adapted to measure the forces passing through the actuators whose position measurement is carried out. Thus, if the position of an actuator is measured, the forces passing through this same actuator are also measured.

[0057] The method 800 comprises a third step 830 of receiving by a suitable computer the positions measured by the at least two position sensors and the forces measured by the at least two force sensors. Thus, a computer is dedicated to a single moving surface. For example, in [Fig.6] or [Fig.7] or [Fig.8], each moving surface 10 and 11 has a dedicated computer.

[0058] The method 800 comprises a fourth step 840 of calculation by the calculator of the value of a maximum difference between the positions measured by the at least two position sensors. Thus, it is possible to calculate the difference between the position of the first actuator and the position of the second actuator. If the position of more than two actuators is measured, it is possible to identify in advance the maximum position value of an actuator among the set of measured position values ​​and the minimum position value of an actuator among the set of position values. measured. Then the difference is calculated between the maximum position value and the minimum position value previously identified.

[0059] The method 800 comprises a fifth step 850 of calculation by the calculator of the value of a maximum difference between the measured forces passing through the at least two force sensors. The calculation 850 may for example consist of calculating the difference between the forces passing through the first actuator and the forces passing through the second actuator. If the forces for more than two actuators are measured, it is possible to identify beforehand the maximum value of the forces passing through an actuator from among the set of measured force values ​​and the minimum value of the forces passing through an actuator from among the set of measured force values. Then the difference is calculated between the maximum force value and the minimum force value previously identified.

[0060] The method 800 comprises a sixth step 860 of detecting a crossing of the moving surface. The crossing is detected if one of the following two conditions is met: • the absolute value of the maximum difference between the positions measured by the at least two position sensors is greater than a threshold distance difference value. • the absolute value of the maximum difference between the measured forces passing through the at least two force sensors is greater than a threshold force difference value.

[0061] The threshold distance and threshold force difference values ​​are values ​​that have been previously provided to the computer. These values ​​can for example be determined by a user and depend among other things on the characteristics of the moving surface and the aircraft. The threshold distance value is expressed in millimeters, centimeters or meters. The threshold force value is expressed in Newtons. The calculations of this step 860 can be carried out by the computer having carried out the previous steps or by another computer, which will have received the results of the previous steps.

[0062] Optionally, the method 800 comprises a final step 870 of stopping the actuation system of the mobile surface when a cross-section of the surface is detected. This stopping, which can for example be decided by the computer of the monitoring system, thus makes it possible to protect the actuation system when there is a cross-section of the mobile surface. This stopping consists for example of an immobilization of the actuators or a modification of the position of the mobile surface in order to reduce the forces passing through the actuators of the actuation system.

[0063] The invention also relates to a method 900 implemented by the monitoring system 600 according to the invention or by one of the variants of the monitoring system 600 according to the invention. [Fig. 10] is a schematic representation of the method 900.

[0064] The method 900 comprises a first step 910 of measuring the forces passing through the first actuator and through the second actuator among the actuators of the actuation system by the at least two force sensors of the monitoring system. A force is expressed in Newtons. The force sensors are therefore adapted to measure the forces passing through the actuators.

[0065] The method 900 comprises a second step 920 of receiving, by a computer, the forces measured by the at least two force sensors. Thus, a computer is dedicated to a single moving surface. For example, in [Fig.6] or [Fig.7] or [Fig.8], each moving surface 10 and 11 has a dedicated computer.

[0066] The method 900 comprises a third step 930 of determination, by the computer, of the maximum absolute value of a force passing through an actuator among the forces measured by the at least two force sensors.

[0067] The method 900 comprises a fourth step 940 of detecting an over-force passing through an actuator among the actuators of the moving surface if the maximum absolute value of the force passing through the actuator among the forces measured by the at least two force sensors is greater than a threshold force value. Thus this step makes it possible to identify whether one or more actuators among the actuators of the actuation system are subjected to an over-force. The threshold force value is a value which has been previously provided to the computer. This value can be determined by a user and depends among other things on the characteristics of the moving surface and the aircraft. The threshold force value is expressed in Newtons. The calculations of this step can be carried out by the computer which carried out the preceding steps or by another computer, which will have received the results of the preceding steps.

[0068] Optionally, the method 900 comprises a final step 950 of stopping the actuation system of the mobile surface when an excess force passing through an actuator among the actuators of the mobile surface is detected. This stopping thus makes it possible to protect the actuation system. This stopping consists for example of immobilizing the actuators or of modifying the position of the actuators in order to reduce the forces passing through the actuators of the actuation system.

[0069] The methods 800 and 900 can be carried out jointly by the same monitoring system 600. In this case, the steps 820 and 910 are merged to form only one step of measuring the forces passing through the actuators by the at least two force sensors of the monitoring system. In addition, the steps 830 and 920 are merged into a step of receiving, by the computer, the positions measured by the at least two position sensors and forces measured by the at least two force sensors. Finally, the optional steps 870 and 950 can be merged into a step of stopping the system for actuating the moving surface when a crossing of the surface is detected or when an over-force passing through an actuator among the actuators of the moving surface is detected.

[0070] Unless otherwise specified, the same element appearing in different figures has a single reference.

Claims

1. Claims Surveillance system including: - a moving surface of an aircraft; - an actuation system for the moving surface of an aircraft comprising a set of more than two actuators; and - At least two position sensors per moving surface of the aircraft measuring the position of each actuator of a subset of actuators among the set of more than two actuators, the subset of actuators comprising a lower number of actuators than the set of more than two actuators, a first position sensor among the at least two position sensors being adapted to measure a position of a first actuator among the subset of actuators and a second position sensor among the at least two position sensors being adapted to measure a position of a second actuator among the subset of actuators, the first and second actuators being located at the ends of the moving surface; - At least two force sensors per moving surface of the aircraft measuring the forces passing through each actuator of the subset of actuators, a first force sensor among the at least two force sensors being adapted to measure forces passing through the first actuator among the subset of actuators and a second force sensor among the at least two force sensors being adapted to measure forces passing through the second actuator among the subset of actuators; and - A computer configured to detect a crossing of the moving surface and an excess force passing through the first and / or the second actuator from the position obtained by the at least two position sensors and the force measured by the at least two force sensors.

2.

3.

4.

5. A surveillance system according to claim 1 wherein the movable surface is a flap of an aircraft wing or a leading edge slat of an aircraft or a lift spoiler. A monitoring system according to claim 1 or 2 wherein the at least two position sensors are variable differential transducers or resolvers or potentiometers. A monitoring system according to any preceding claim wherein the at least two force sensors are strain gauges or deformation gauges or electromagnetic sensors. A monitoring method (800) implemented by the monitoring system according to any one of the preceding claims, the method (800) comprising: Measuring (810) the position of a first actuator and a second actuator among the subset of actuators of the actuation system by the at least two position sensors of the monitoring system; Measuring (820) the forces passing through the first actuator and the second actuator among the subset of actuators of the actuation system by the at least two force sensors of the monitoring system; Receive (830), by the computer, the positions measured by the at least two position sensors and the forces measured by the at least two force sensors; Calculate (840), by the calculator, the absolute value of a maximum difference between the positions measured by the at least two position sensors; Calculate (850), by the calculator, the absolute value of a maximum difference between the measured forces passing through the at least two force sensors; and Detect (860) a crossing of the moving surface if: • the absolute value of the maximum difference between the positions measured by the at least two position sensors is greater than a threshold distance value difference; or • the absolute value of the maximum difference between the measured forces passing through the at least two force sensors is greater than a threshold force difference value.

6. Method (800) according to claim 5 further comprising: - Stopping (870) the actuating system of the movable surface when a crossing of the surface is detected.

7. Monitoring method (900) implemented by the monitoring system according to any one of claims 1 to 4, the method (900) comprising: - Measuring (910) the forces passing through each actuator of the subset of actuators by the at least two force sensors of the monitoring system; - Receiving (920), by the computer, the forces measured by the at least two force sensors; - Determining (930), by the computer, the maximum absolute value of a force passing through an actuator among the forces measured by the at least two force sensors; and - Detecting (940) an over-force passing through the actuator among the subset of actuators of the moving surface if the maximum absolute value of the force passing through the actuator among the forces measured by the at least two force sensors is greater than a threshold force value.

8. Method (900) for monitoring a moving surface of an aircraft according to claim 7 further comprising: - Stopping (950) the system for actuating the moving surface when an over-force passing through one of the actuators of the moving surface is detected.

9. An aircraft comprising the surveillance system according to any one of claims 1 to 4.

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