Mechanical flight control system of an aircraft for measuring forces in the mechanical flight control system

Abstract

The invention relates to a mechanical flight control system of an aircraft for measuring forces in the mechanical flight control system. The mechanical flight control system (2) is provided with actuators (30) comprising at least one electric motor and one duplex calculator per electric motor, each duplex calculator comprising a control channel, a monitoring channel and two input interfaces, and with a force measuring device (40) comprising a plurality of measuring channels, each measuring channel comprising a sensor, an electronic module and an output interface connected to one of the input interfaces. The electronic module is connected to the sensor so as to generate an analog measurement signal and is configured to digitize the analog measurement signal and then convert it into a digital transmission signal carrying a transmission value representative of a force in the mechanical flight control system (2), at least one of the measuring channels applying a delta-sigma modulation.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of FR2413153, filed on November 28, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention belongs to the field of aircraft flight control systems.

[0004] This invention relates to a mechanical flight control system for an aircraft, including a force measuring device, and to an aircraft equipped with the mechanical flight control system. The invention also relates to a method for measuring the values ​​of forces representing the forces in the mechanical flight control system of an aircraft.

[0005] An aircraft may include movable aerodynamic control surfaces controlled by a mechanical flight control system to steer the aircraft. Such aerodynamic control surfaces may include, for example, rotor blades, propeller blades, ailerons, or rudders.

[0006] A mechanical flight control system may include several connecting links that form a link between control elements (such as levers, joysticks, or rudder sticks) and aerodynamic control surfaces that are optionally moved via servo control. The mechanical flight control system may also include one or more actuators.

[0007] For example, a tandem actuator can be inserted between two connecting rods of a mechanical flight control system. The extension or retraction of the tandem actuator causes a change in the sequence of transmissions to the servo control without affecting the position of the control components.

[0008] In another example, a parallel actuator (also known as a "trimming actuator") can connect a control element or a connecting rod of a mechanical flight control system to a fixed point on the aircraft structure. Such a parallel actuator can, for example, cause a simultaneous change in the sequence of transmissions to servo control and the position of the control element. The parallel actuator can also enable the control element to be anchored in a defined position. Such a parallel actuator can also act as a gentle or direct stop to specifically indicate to the pilot that flight limits have been reached and / or exceeded, or even to indicate a tactile return.

[0009] Furthermore, to achieve the required level of safety, these actuators may include two motors, each controlled by a separate or even different duplex calculator. Such a duplex calculator therefore includes a first calculation channel dedicated to controlling the movement of the actuators and a second calculation channel dedicated to monitoring the first calculation channel, which enables the first calculation channel to be disabled if an anomaly or malfunction is detected.

[0010] Regardless of their type, these actuators can be servo-controlled based on force. For this purpose, and in order to adjust the actuator control setpoint, force measurement is required in mechanical flight control systems, and particularly on connecting rods. Background Technology

[0011] One or more analog force measuring devices can be incorporated, for example, into a mechanical flight control system as described in document EP 3301019. Such force measuring devices may be particularly sensitive to confined environments. Furthermore, due to the numerous electrical connections of these force measuring devices, they may induce non-negligible friction on control components.

[0012] Furthermore, the signals provided by the force measurement devices arranged on the mechanical flight control system can be processed and / or filtered to, for example, improve their resolution or limit their noise. Analog signals can also be converted into digital signals, for example, as described in document US2014 / 0266259.

[0013] To meet the high safety requirements of the mechanical flight control system attached to the aircraft, the force measurement device installed on the mechanical flight control system can be of the duplex type, i.e., including two independent measurement channels, or even quad-multiplex type, i.e., including four independent measurement channels. In particular, using a quad-multiplex force measurement device allows for a loss of less than or equal to 10 in cases of loss of one or more measurement channels. -6 The failure rate per flight hour, and for undetected erroneous signals emitted on one or more measurement channels and mechanical failures leading to the loss of control components, can be less than or equal to 10. -10 Failure rate per flight hour.

[0014] Additionally, documents US2019 / 0233087, US2019 / 0300169, EP0606469, and US2022 / 0380023, as well as Holger... The publications “Aviation Electronics and Aircraft Control Technology: Communication, Navigation, and Surveillance” (2013-02-06) and XP055488213 are also known. Summary of the Invention

[0015] Therefore, one object of the present invention is an innovative method for measuring forces in a mechanical flight control system of an aircraft. Another object of the present invention includes a mechanical flight control system with a force sensor capable of applying this method, and an aircraft including such a mechanical flight control system.

[0016] Therefore, the present invention relates to a mechanical flight control system for an aircraft, comprising at least one connecting rod and an actuator, the actuator including at least one electric motor and a duplex calculator for each electric motor, each duplex calculator including a control channel, a monitoring channel, and two input interfaces respectively connected to the control channel and the monitoring channel. The mechanical flight control system also includes a force measuring device arranged on the connecting rod and configured to control the actuator. The control channel and the monitoring channel of each duplex calculator constitute the calculation channel of the duplex calculator.

[0017] The force measuring device includes at least two measuring channels, each connected to two input interfaces of the at least one duplex calculator, and each measuring channel includes a sensor, an electronic module, and an output interface. The output interface is connected to one input interface of the at least one duplex calculator. The electronic module is connected to the sensor to generate an analog measurement signal. The electronic module is configured to perform digitization of the analog measurement signal to convert it into a digital measurement signal. The electronic module is also configured to perform conversion of the digital measurement signal into a digital transmission signal carrying a force transmission value representing a force in the mechanical flight control system. At least one measuring channel applies Δ-Σ modulation to digitize the analog measurement signal and applies Manchester encoding and low-voltage differential signaling to convert the digital measurement signal into a digital transmission signal. The mechanical flight control system includes a clock for each measuring channel designed to time the Δ-Σ modulation.

[0018] A mechanical flight control system may be connected at one end to a control element, such as a joystick, lever, or rudder stick, and at the other end optionally to the aerodynamic control surfaces of the aircraft, such as one or more blades of a rotor or one or more flaps, via servo control.

[0019] The electronic module may include printed circuitry that carries electronic components such as integrated circuits and / or microswitches. In this case, the electronic module does not employ programs stored in memory to execute method steps.

[0020] Alternatively, the electronic module may include a calculator (e.g., a microcontroller) and memory storing a program applied by the calculator to perform the method steps.

[0021] The analog measurement signal carries the value measured by the sensor, which is a function of the force experienced or transmitted by the mechanical flight control system and, in particular, the connecting rod of the mechanical flight control system.

[0022] Δ-Σ modulation allows measurements acquired in analog form to be converted into digitized values ​​carried by a digital measurement signal. This digital measurement signal is encoded on one or more bits through oversampling, where the rate of change between 0 and 1 is a function of the amplitude of the analog measurement signal. This Δ-Σ modulation is timed by a clock associated with the relevant measurement channel. The use of the timing signal transmitted by this clock and the frequency of this timing signal affect the resolution and accuracy of the digital measurement and transmission signals. The digitized value carried by the digital measurement signal is a function of the measured value, and therefore also a function of the force experienced or transmitted by the mechanical flight control system.

[0023] Then, Manchester encoding and Low Voltage Differential Signaling (LVDS) enable the digitized value carried by the digital measurement signal to be converted into the transmitted value carried by the digital transmission signal. Manchester encoding is a synchronous encoding that has the advantage of transmitting the transmitted value and the time signal provided by the clock through a single digital transmission signal. In each clock cycle, a bit is encoded in the middle of the cycle by a transition from 0 to 1 or from 1 to 0 (depending on whether the bit to be encoded is "1" or "0"), thus allowing the clock to be reconstructed by the receiver of the digital transmission signal.

[0024] Furthermore, compared to the transistor-to-transistor logic (TTL) physical layer, low-voltage differential signals have advantages such as being less affected by electrical noise, supporting higher frequency signals, and traveling longer distances. Low-voltage differential signals also require the use of twisted wires and smaller surge protection devices.

[0025] Therefore, the transmitted value carried by the digital transmission signal is a function of the digitized value, and thus also a function of the force experienced or transmitted by the mechanical flight control system.

[0026] Therefore, this mechanical flight control system advantageously enables the transmission of precise values ​​to the actuator for optimal control through continuous processing operations applied to both analog and digital measurement signals. These transmitted values ​​are particularly insensitive to electromagnetic interference and represent forces within the mechanical flight control system.

[0027] For example, the actuator can be a series actuator connecting two links of a mechanical flight control system. The actuator can also be a parallel actuator connecting the control components or links of the mechanical flight control system to fixed points on the aircraft structure. The actuator can be hydraulic, pneumatic, or electric. Therefore, the flight control system enables control of the movement of aerodynamic control surfaces, such as controlling the blade pitch or flap orientation via optional servo control.

[0028] The mechanical flight control system according to the invention may also include one or more of the following features, either individually or in combination.

[0029] In one possibility, the sensor may include at least one strain gauge, a piezoelectric sensor, or a linear displacement sensor known as a "linear variable differential transformer" (LVDT). The sensor can then measure the displacement or deformation of the connecting rod, which is a function of the force experienced or transmitted by the connecting rod in the flight control system between the control member and the servo control of the aerodynamic control surface.

[0030] Each measurement channel may include the same type of sensor. Alternatively, at least two measurement channels may each include different types of sensors to distinguish these at least two measurement channels.

[0031] According to one possibility compatible with the foregoing, the force measuring device may include a clock. In particular, the electronic module of each measuring channel may include a clock, thereby ensuring the independence of each measuring channel.

[0032] Alternatively, the actuator may include a clock. Specifically, the actuator's duplex calculator may include such a clock on each of the control and monitoring channels. The time signal of each clock is then transmitted via input and output interfaces to the measurement channel of the force measuring device. As a result, the force measuring device can be simplified, lighter, and cheaper without such a clock.

[0033] According to one possibility compatible with the foregoing possibilities, for at least one measurement channel, the electronic module may include an analog-to-digital converter for digitizing analog signals, and the output interface includes a digital bus.

[0034] One or more measurement channels, including such an analog-to-digital converter, are one or more measurement channels that do not apply Δ-Σ modulation.

[0035] Therefore, advantageously, the processing of the analog measurement signal is performed differently by at least two measurement channels, at least one measurement channel applying Δ-Σ modulation, and at least one measurement channel applying analog-to-digital conversion.

[0036] In this way, at least the two measurement channels are different, at least in terms of the digitization methods used. Additionally, the electronic modules for this or these measurement channels can be different, thus also providing different techniques.

[0037] For example, the digital bus can be a known type selected from the following: TIA / EIA-485, TIA / EIA-422, ARINC 429, CAN bus, I2C, AFDX, time-triggered Ethernet, FlexRay, LIN, or MIL-STD-1553.

[0038] According to one possibility compatible with the foregoing possibilities, at least one measurement channel may include a memory in which at least one calibration law is stored, and the at least one duplex calculator is configured to apply calibration to the transmitted value carried by the digital transmission signal of each measurement channel using the at least one calibration law.

[0039] More specifically, it is known that the values ​​measured by a sensor can be modified or drifted before they are transmitted by the force measuring device. For example, such drift may be related to various factors, such as the voltage, temperature, and / or aging of each measuring channel. Errors may also be introduced by drift of the electronic components used on the measuring channel, or even by the sensor itself.

[0040] In this way, the value measured by the sensor and carried by the analog measurement signal can be different from the value carried by the digital transmission signal.

[0041] Therefore, calibration can improve the accuracy of the force transmission values ​​in the mechanical flight control system represented by each measurement channel.

[0042] The modifications or deviations to be corrected can be determined through calculation, testing, or simulation, and implemented in one or more calibration laws. Depending on the complexity of the correction to be performed, calibration laws may include a single calibration formula, a table containing several calibration formulas, or a calibration table.

[0043] A single calibration formula provides a corrected value for the representing force as a function of the transmitted value. The calibration formula table contains multiple formulas applied to obtain a corrected value for the representing force, defined as a function of the transmitted value. The calibration table includes a correspondence between the transmitted and corrected values.

[0044] Furthermore, calibration laws can be universal and the same for all measurement channels. Alternatively, calibration laws can be specific to each measurement channel (especially when these measurement channels are different), and therefore differ between one measurement channel and another.

[0045] Therefore, the at least one duplex calculator of the actuator can apply calibration to each control and monitoring channel to correct the transmitted values ​​carried by the digital transmission signals received from each measurement channel, the at least one measurement channel including a memory that transmits the at least one calibration law to the duplex calculator.

[0046] Alternatively, the calibration can be performed by the force measuring device and by each measuring channel before the digital transmission signal is transmitted.

[0047] Alternatively, the actuator may include at least one memory in which one or more calibration laws are stored, and the at least one duplex calculator is configured to apply calibration to the transmitted values ​​carried by the digital transmission signals of each measurement channel using the at least one calibration law.

[0048] In this case, one or more calibration laws may be stored in at least one memory of the at least one duplex calculator of the actuator, while the measurement channel does not store any calibration laws.

[0049] For example, in the presence of a single duplex calculator, each control and monitoring channel of the duplex calculator may include a memory storing one or more calibration laws that the duplex calculator applies to the transmitted values ​​carried by digital transmission signals traveling in the control and monitoring channels of the duplex calculator.

[0050] According to one possibility compatible with the foregoing possibilities, the actuator may include two electric motors and two duplex calculators, and the force measuring device includes two first measuring channels connected to the control channels of the two duplex calculators and two second measuring channels connected to the monitoring channels of the two duplex calculators, wherein the first measuring channels are different from the second measuring channels.

[0051] Therefore, using two duplex calculators associated with the four measurement channels of the force measuring device makes it possible to obtain a four-way multiplexer capable of mitigating faults at both the measurement channel level of the force measuring device and the control or monitoring channel level of the duplex calculator. Furthermore, using different measurement channels, depending on whether they are control or monitoring channels connected to the duplex calculator, allows for limiting the sensitivity of the force measuring device to certain faults.

[0052] Therefore, the mechanical flight control system according to the invention can improve the fault tolerance of the force measuring device and / or actuator. Thus, in particular, the mechanical flight control system according to the invention can achieve a high level of safety, for example, corresponding to a level less than or equal to 10. -10 Failure rate per flight hour.

[0053] The present invention also relates to an aircraft having at least one movable aerodynamic control surface for turning the aircraft, and including at least one mechanical flight control system as described above for controlling the aerodynamic control surface.

[0054] Another object of the present invention is a method for measuring the value of forces in a mechanical flight control system of an aircraft using a force measuring device.

[0055] The force measuring device is provided with at least two measuring channels, each measuring channel including a sensor, an electronic module, and an output interface arranged on a connecting rod of the flight control system, and the method includes the following steps applied to each measuring channel of the force measuring device:

[0056] Use sensors to generate analog measurement signals;

[0057] Using electronic modules, analog measurement signals are digitized to form digital measurement signals;

[0058] The electronic module converts the digital measurement signal into a digital transmission signal, which carries the transmission value of the force in the mechanical flight control system.

[0059] Digital signals are transmitted via the output interface of the measurement channel through the electronic module; and

[0060] The transmitted value is calibrated by applying calibration laws, which include a single calibration formula, a table of calibration formulas, or a calibration table.

[0061] On at least one measurement channel, the digitization is performed by clock-timed Δ-Σ modulation, and the conversion is performed by Manchester encoding and low-voltage differential signaling.

[0062] Therefore, the method according to the invention processes an analog measurement signal that carries a measurement value as a function of force in a mechanical flight control system of an aircraft, digitizes it, and then modifies the obtained digital measurement signal to obtain a digital transmission signal carrying a transmission value, which is transmitted toward the device item and, for example, a series or parallel actuator of the mechanical flight control system.

[0063] As a result of these processes, the transmitted values ​​are less sensitive to, or even unaffected by, the electromagnetic environment, and are more accurate than current stress measurement schemes by preventing the accuracy loss associated with the transmission of purely analog signals and potential noise introduced due to interference. The use of Δ-Σ modulation also contributes to the good accuracy of representing force values.

[0064] This method can be specifically implemented by the aforementioned mechanical flight control system. Attached Figure Description

[0065] The invention and its advantages will become more apparent from the following description of examples given by way of illustration with reference to the accompanying drawings, in which:

[0066] · Figure 1 This is a view of the mechanical flight control system according to the present invention;

[0067] · Figure 2 It includes Figure 1A view of the aircraft's mechanical flight control system;

[0068] · Figure 3 yes Figure 1 A partial view of the mechanical flight control system; and

[0069] · Figure 4 yes Figure 1 A partial view of the mechanical flight control system. Detailed Implementation

[0070] Elements present in more than one figure are given the same reference numerals in each of those figures.

[0071] Figure 1 The mechanical flight control system 2 for aircraft 1 is shown.

[0072] This mechanical flight control system 2 may control the movement of one or more aerodynamic control surfaces 10 via servo control 28, enabling the aircraft 1 to be steered. Such aerodynamic control surfaces 10 may include the first blade 12 of the main rotor 11, the second blade 14 of the yaw motion control rotor 13, or even propeller blades, ailerons, or rudders.

[0073] according to Figure 2 In the example, aircraft 1 can be a helicopter, which includes a main rotor 11 and a yaw control rotor 13. The main rotor 11 is provided with a first blade 12 with variable pitch, and the yaw control rotor 13 is provided with a second blade 14 with variable pitch. In this case, aircraft 1 can include multiple mechanical flight control systems 2, which respectively control the total pitch change of the first blade 11 via a total pitch lever 25, control the periodic pitch change of the first blade 12 via a periodic pitch control stick 26, and control the total pitch change of the second blade 14 via a rudder stick 27.

[0074] Independent of the properties of the aerodynamic control surface 10, the mechanical flight control system 2 includes control elements 25, 26, 27 and multiple connecting rods 21, 21', 22, 22', 22", 23, 24, which are optionally hinged to each other via crank 29 or even via a combiner. The mechanical flight control system 2 also includes one or more actuators 30 and a force measuring device 40. Reference numeral "30" indicates any actuator of the mechanical flight control system 2, and reference numerals "301" and "302" indicate specific actuators as necessary.

[0075] according to Figure 1 As an example, the mechanical flight control system 2 may include at least one parallel actuator 301 and at least one series actuator 302.

[0076] According to the example shown, the parallel actuator 301 connects the connecting rod 21' of the mechanical flight control system 2 to the fixed point of the structure 15 via the connecting rod 303. The parallel actuator 301 may include, for example, a cylinder or an electric motor.

[0077] According to the example shown, two tandem actuators 302 can connect two of the connecting rods 22, 22', 22" of the mechanical flight control system 2 via one end of their respective ends. These tandem actuators 302 may, for example, each include an electric cylinder.

[0078] Independent of its type and as Figure 3 and Figure 4 As shown, the actuator 30 includes at least one electric motor 31, 32 and a duplex calculator 33, 34 for each electric motor 31, 32. Each duplex calculator 33, 34 is provided with two independent calculation channels, namely control channels 35, 36 and monitoring channels 37, 38, and an input interface 351, 361, 371, 381 for each calculation channel 35, 36, 37, 38.

[0079] Each computing channel 35, 36, 37, 38 includes processing units 352, 362, 372, 382, ​​which may include, for example, a processor, at least one integrated circuit, or at least one logic circuit. These examples do not limit the scope of the term "processing unit". The term "processor" may be used interchangeably with a central processing unit or CPU, a graphics processing unit or GPU, a digital signal processor or DSP, a microcontroller, etc.

[0080] Force measuring device 40 is arranged in the mechanical flight control system 2, and for example, on one of the connecting rods 21-24. In particular, the force measuring device 40 enables the direct or indirect measurement of the force experienced or transmitted by the connecting rod 21-24.

[0081] The force measuring device 40 includes at least two measuring channels 41, each measuring channel being provided with a sensor 42, an electronic module 43, and an output interface 44 arranged on connecting rods 21-24. If necessary, individual reference numerals "41", "42", "43", and "44" generally indicate a measuring channel or a component thereof, and the letters "A", "B", "C", or "D" are associated with these reference numerals to indicate a specific measuring channel or a component thereof.

[0082] Electronic module 43 may include, for example, various electronic components connected to each other via printed circuits or equivalents, such as integrated circuits, microswitches and / or passive electronic components.

[0083] The output interface 44 of each measurement channel 41 is electrically connected via electrical harness 20 to the individual input interfaces 351, 361, 371, and 381 of the calculation channels 35, 36, 37, and 38 of the actuator 30, and each input interface 351, 361, 371, and 381 is connected to the individual output interface 44.

[0084] For example, sensor 42 may include at least a strain gauge, a piezoelectric sensor, or a linear variable differential transformer (LVDT). In these examples, sensor 42 may measure the displacement or deformation of connecting rods 21-24, which is a function of or even proportional to the force experienced or transmitted by the connecting rods 21-24, and therefore a function of or even proportional to the force experienced or transmitted by the flight control system 2.

[0085] Measurement channels 41 may optionally include different types of sensors 42 in order to make these measurement channels 41 particularly different.

[0086] Exemplary embodiments of the force measuring device 40 and the actuator 30 are described in Figure 3 and Figure 4 As shown in the image.

[0087] according to Figure 3 In the first example shown, the force measuring device 40 includes two measuring channels 41A and 41b, and the actuator 30 includes a single duplex calculator 33. The two measuring channels 41A and 41B are connected to the control channel 35 and the monitoring channel 37 via output interfaces 44A and 44B and input interfaces 351 and 371, respectively.

[0088] The processing unit 352 of the control channel 35 of the duplex calculator 33 includes a clock 355 and a memory 356, and the processing unit 372 of the monitoring channel 37 of the duplex calculator 33 also includes a clock 355.

[0089] according to Figure 4 In the second embodiment shown, the force measuring device 40 includes four measuring channels 41A, 41B, 41C, and 41D, and the actuator 30 includes two duplex calculators 33 and 34. The four measuring channels 41A, 41B, 41C, and 41D are connected to control channels 35 and 36 and monitoring channels 37 and 38 respectively via output interfaces 44A, 44B, 44C, and 44D and input interfaces 351, 361, 371, and 381.

[0090] The electronic modules 43A, 43B, 43C, and 43D of the four measurement channels 41A, 41B, 41C, and 41D include clocks 435A, 435B, 435C, and 435D. The electronic module 43A of the first measurement channel 41A also includes a memory 436.

[0091] According to this second example, the two measurement channels 41A and 41C connected to the control channels 35 and 37 of the two duplex calculators 33 and 34 can be different from the two measurement channels 41B and 41D connected to the monitoring channels 36 and 38 of the two duplex calculators 33 and 34.

[0092] Independent of these two exemplary embodiments, each measurement channel 41 generates an analog measurement signal carrying a measured value, which is a function of the force experienced or transmitted in the mechanical flight control system 2, by means of a sensor 42. The electronic module 43 of each measurement channel 41 receives this analog measurement signal and can apply various processes to it to first digitize it to obtain a digital measurement signal carrying a digitized value, which is a function of the measured value and therefore a function of the force experienced or transmitted in the mechanical flight control system 2. Secondly, the electronic module 43 converts the digital measurement signal into a digital transmission signal carrying a transmission value, which is a function of the digitized value and therefore a function of the force experienced or transmitted in the mechanical flight control system 2.

[0093] Specifically, at least one measurement channel 41 or even the electronic module 43 of each measurement channel 41 applies Δ-Σ modulation to digitize the analog measurement signal, and then applies Manchester encoding and low-voltage differential signaling to obtain the digital transmission signal.

[0094] The transmitted values ​​obtained in this way are accurate and relatively unaffected by the electromagnetic environment.

[0095] The time signals of clocks 355 and 435 are specifically used by electronic module 43 to perform Δ-Σ modulation and apply Manchester encoding. In addition, when clock 355 is in duplex calculators 33 and 34, the time signals are transmitted to each measurement channel 41 via input interfaces 351, 361, 371, 381 and output interface 44.

[0096] In addition to at least one measurement channel 41A applying Δ-Σ modulation, and as Figure 4 As shown, the electronic module 43D of at least one other measurement channel 41D may include an analog-to-digital converter 48D for digitizing analog measurement signals, and the output interface 44D of the at least one other measurement channel 41D then includes a digital bus 49D to enable the conversion of digital measurement signals into digital transmission signals. In this case, the other measurement channel 41D does not apply Δ-Σ modulation or Manchester encoding. Therefore, the mechanical flight control system 2 according to the invention advantageously includes at least two different measurement channels 41A, 41D, thereby mitigating potential failures affecting measurement channel 41.

[0097] Furthermore, memories 356 and 436 can store one or more calibration laws. These calibration laws enable the correction of deviations between the transmitted value carried by the digital transmission signal and the value measured by sensor 42.

[0098] The initial correction provided by this or these calibration laws can be obtained by implementing a so-called "static" calibration, which is only a function of the transmitted value. This static calibration can specifically compensate for the inherent gain and / or offset errors of measurement channel 41.

[0099] A second correction can be achieved by implementing a so-called "dynamic" calibration, which is a function of the transmitted value and the temperature of the associated measurement channel 41. This dynamic calibration can correct for gain and offset errors related to the temperature of the measurement channel 41. To achieve this dynamic calibration, a temperature sensor 47 can be integrated into each measurement channel 41 of the force measuring device 40 to measure the temperature of each measurement channel 41.

[0100] Regardless of the calibration achieved, calibration laws may include a single calibration formula, a table containing several calibration formulas, or a calibration table. A single calibration formula gives a correction value representing the force, which is a function of the transmitted value and, where applicable, a function of the temperature of the measurement channel 41 for dynamic calibration.

[0101] The calibration formula table includes several formulas applied to obtain a correction value representing the force. This correction value is defined as a function of the transmitted value, and, where appropriate, as a function of the temperature of the measurement channel 41 for dynamic calibration. If the table does not provide a formula for the current transmitted value, at least one algorithm can be used to perform a search for a value close to the correction value, such as through a bisection method.

[0102] The calibration table includes a correspondence between transmitted values ​​and correction values, where, if necessary, for dynamic calibration, the correction value is a function of the temperature of the measured channel 41. Similarly, if the table does not provide a correction value for the current transmitted value, at least one algorithm can be used to perform a search for a value close to the correction value, such as through binary search.

[0103] Therefore, one or more duplex calculators 33, 34 of actuator 30 can use one or more calibration laws to calibrate the transmitted value carried by the digital transmitted signal received from each measurement channel 41. Alternatively, this calibration can be performed by force measuring device 40, particularly by electronic module 43 for each measurement channel 41, before transmitting the digital transmitted signal.

[0104] according to Figure 3In the example, the first processing unit 352 of the duplex calculator 33 of the actuator 30 includes a memory 356 in which one or more calibration laws are stored. Therefore, the first processing unit 352 can directly apply calibration to the transmitted value carried by the digital transmission signal received by the first control channel 35. Additionally, a second processing unit 326 communicates with the first processing unit 352 to receive one or more calibration laws so as to apply calibration to the transmitted value carried by the digital transmission signal received by the first monitoring channel 36.

[0105] In the presence of multiple duplex calculators 33, 34, only one of these duplex calculators 33, 34 may include a memory 352, and transmit the calibration law or these calibration laws to one or more other duplex calculators 33, 34 via a wired or wireless link. In this way, a single memory 352 is sufficient for at least two duplex calculators 33, 34, simplifying at least one of these duplex calculators 33, 34 and also limiting their cost.

[0106] according to Figure 4 In the example, only the first electronic module 43A includes a memory 436 storing one or more calibration laws. The one or more calibration laws are then transmitted to at least one duplex calculator 33, 34 to generate calibration of the transmitted values ​​on each of the control channels 35, 37 and monitoring channels 36, 38.

[0107] In the presence of multiple duplex calculators 33, 34, one of these duplex calculators 33, 34 can receive one or more calibration laws via measurement channel 41, thereby storing the calibration laws. Then, the duplex calculator 33, 34 can transmit one or more calibration laws to one or more other duplex calculators 33, 34 via wired or wireless links.

[0108] Regardless of the calibration performed, the calibration law can be the same for all measurement channels 41. Alternatively, the calibration law can differ between one measurement channel 41 and another, especially when these measurement channels 41 are different.

[0109] Where the calibration law is specific to each measurement channel 41, a single measurement channel 41 may include a memory 436 to store all calibration laws. Alternatively, each measurement channel 41 may include a memory 436 storing calibration laws to be specifically applied to that measurement channel 41. Alternatively, each measurement channel may include a memory 436 storing all calibration laws associated with each measurement channel 41 in order to mitigate the potential failure of one of the memories of these measurement channels 41.

[0110] In addition, the mechanical flight control system 2 can implement a method for measuring the value of the force in the mechanical flight control system 2 using the force measuring device 40.

[0111] The method includes the following steps applied to each measuring channel 41 of the force measuring device 40:

[0112] First, an analog measurement signal is generated using the sensor 43 of each measurement channel 41, which carries the value measured by the sensor 43.

[0113] Then, the electronic module 43 of each measurement channel 41 is used to digitize the analog measurement signal to form a digital measurement signal carrying the digitized value.

[0114] The digital measurement signal is then converted into a digital transmission signal by the electronic module 43 of each measurement channel 41, which carries the transmission value of the force in the mechanical flight control system 2.

[0115] For at least one measurement channel 41, the digitization is performed by clock-timed Δ-Σ modulation, and the conversion is performed by Manchester encoding and low-voltage differential signaling.

[0116] The digital transmission signal is transmitted to the output interface of the measurement channel (e.g., to actuator 30) via these input interfaces 351, 361, 371, and 381.

[0117] Finally, calibration of the transmitted values ​​can be generated by applying calibration laws, which include a single calibration formula, a calibration formula table, or a calibration table.

[0118] This calibration can be performed equally well in one or more duplex calculators 33, 44 of the actuator 30 or even in the electronic module 43 of the measurement channel 41 of the force measuring device 40.

[0119] Naturally, the invention can undergo many variations in its implementation. Although several embodiments have been described above, it should be readily understood that it is not conceivable to exhaustively identify all possible embodiments. Of course, any of the described devices can be replaced with equivalent devices without departing from the scope of the invention and the claims.

Claims

1. A mechanical flight control system (2) for an aircraft (1), comprising at least one connecting rod (21-24) and an actuator (30), said actuator (30) comprising at least one electric motor (31, 32) and a duplex calculator (33, 34) for each electric motor (31, 32), each duplex calculator (33, 34) comprising a control channel (35, 37), a monitoring channel (36, 38) and two input interfaces (351, 361, 371, 381) respectively connected to the control channel (35, 37) and the monitoring channel (36, 38), said mechanical flight control system (2) comprising a force measuring device (40) disposed on said connecting rod (21-24) and configured to control said actuator (30), The force measuring device (40) includes at least two measuring channels (41) respectively connected to the two input interfaces (351, 361, 371, 381) of the duplex calculator (33, 34), and each measuring channel (41) includes a sensor (42), an electronic module (43), and an output interface (44). The output interface (44) is connected to one of the input interfaces (351, 361, 371, 381) of the duplex calculator (33, 34). The electronic module (43) is connected to the sensor (42) to generate an analog measurement signal. The electronic module (43) is configured... To perform the digitization of the analog measurement signal in order to convert it into a digital measurement signal, the electronic module (43) is configured to perform the conversion of the digital measurement signal into a digital transmission signal carrying a force transmission value in the mechanical flight control system (2), at least one of the measurement channels (41) applies Δ-Σ modulation to digitize the analog measurement signal, and applies Manchester encoding and low-voltage differential signaling techniques to convert the digital measurement signal into the digital transmission signal, the mechanical flight control system (2) including a clock (355, 435) for each measurement channel designed to time the Δ-Σ modulation.

2. The mechanical flight control system (2) according to claim 1, in, The sensor (42) includes at least one strain gauge, piezoelectric sensor or linear displacement sensor.

3. The mechanical flight control system (2) according to claim 1, in, The force measuring device (40) or the actuator (30) includes the clock (355, 435).

4. The mechanical flight control system (2) according to claim 1, in, For at least one of the measurement channels (41), the electronic module (43) includes an analog-to-digital converter (48) and the output interface (44) includes a digital bus (49).

5. The mechanical flight control system (2) according to claim 1, in, At least one of the measurement channels (41) includes a memory (436) in which at least one calibration law is stored, and the duplex calculator (33, 34) is configured to apply calibration to the transmitted value carried by the digital transmission signal of each measurement channel (41) using the calibration law.

6. The mechanical flight control system (2) according to claim 1, in, The actuator (30) includes at least one memory (356) storing at least one calibration law, and the duplex calculator (33, 34) is configured to apply calibration to the transmitted value carried by the digital transmitted signal of each measurement channel (41) using the calibration law.

7. The mechanical flight control system (2) according to claim 1, in, The actuator (30) includes two electric motors (31, 32) and two duplex calculators (33, 34). The force measuring device (40) includes two first measuring channels (41A, 41C) connected to the control channels (35, 37) of the two duplex calculators (33, 34) and two second measuring channels (41B, 41D) connected to the monitoring channels (36, 38) of the two duplex calculators (33, 34). The first measuring channels (41A, 41C) are different from the second measuring channels (41B, 41D).

8. An aircraft (1) having at least one movable aerodynamic control surface (10) for moving the aircraft (1) and at least one mechanical flight control system (2) according to claim 1 for controlling the aerodynamic control surface (10).

9. A method for measuring the value of a force in a mechanical flight control system (2) representing an aircraft (1) using a force measuring device (40), in, The force measuring device (40) is provided with at least two measuring channels (41), each measuring channel including a sensor (42), an electronic module (43), and an output interface (44) arranged on the connecting rods (21-24) of the mechanical flight control system (2), and the method includes the following steps applied to each measuring channel (41) of the force measuring device (40): • Use the sensor (42) to generate an analog measurement signal; • The analog measurement signal is digitized using the electronic module (43) to form a digital measurement signal; • The electronic module (43) converts the digital measurement signal into a digital transmission signal, which carries a force transmission value representing the mechanical flight control system (2); as well as • The electronic module (43) transmits the digital transmission signal to the output interface (44) of the measurement channel (41); as well as • The transmitted value is calibrated by applying calibration laws, which include a single calibration formula, a calibration formula table, or a calibration table; • On at least one measurement channel, the digitization is performed by Δ-Σ modulation timed by a clock (355, 435), and the conversion is performed by Manchester encoding and low-voltage differential signaling techniques.

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