Coupling method, related system and apparatus for redundant servo devices in an actuator control system

Abstract

The present invention relates to a system (30) for controlling actuators (TS) comprising a plurality of redundant servo units (FC-1, FC-2, FC-3) generating values ​​of the same magnitude (Δ1, Δ2, Δ3) from the same setpoint (Gsp) and the same measurement data (Gs1, Gs2, Gs3), the redundant servo units (FC-1, FC-2, FC-3) further communicating with each other (B) so that each redundant servo unit (FC-1, FC-2, FC-3) has access by reading the most recent values ​​of the variables (Δ1, Δ2, Δ3) generated by the redundant servo unit and implements a method for correcting each generated value by combining them. Thus, the present invention prevents discrepancies between these variables (Δ1, Δ2, Δ3). Such a system (30) may be equipped in a vehicle having a driver, passengers, and / or a load consisting of goods or cargo, and having one or more actuators controlled in this manner.

Description

[Technical Field]

[0001] This invention relates to the field of servo systems for actuators. “Servo system” means any system designed to reach a setpoint as quickly as possible and maintain it as much as possible regardless of disturbances caused by the system environment. This invention particularly relates to the field of such servo systems when the servo system is referred to as “redundant” or “multi-redundant” and is used, for example, on land, water, or air transport. This invention is primarily described in the context of aircraft flight control, whether the pilot is present inside the aircraft or, as may be the case with a drone, far from it, but this does not limit the invention in any way or in any way. Such aircraft generally take the form of a propulsion system, preferably but not limited to a vertical propulsion system, which is adapted or designed to ensure the lifting and movement of the load, whether the load consists of a pilot, one or more human or animal passengers, and / or one or more solid or liquid articles that the propulsion system ensures transport. [Background technology]

[0002] The principle of servo-controlling a variable or its characteristics generally consists of measuring the variable generated by the system and comparing it to a setpoint. To ensure the generated variable reaches and maintains a target value defined by the setpoint as quickly as possible, the setpoint is corrected considering the difference between the value generated by the system and the setpoint. A particular servo-control system acts on one or more characteristics of the servo-controlled variable, such as position, velocity, or acceleration. For this reason, such systems are sometimes described as "negative feedback," "degenerate feedback," or "closed-loop" control systems. Furthermore, it is possible to servo-control various variables and / or the characteristics of these variables, ultimately generating commands to the actuator. The concepts of stability and accuracy often conflict with the concept of speed. To improve the performance of a servo system, it is generally necessary to include compensators in the servo loop. Various types of compensators exist, and their operation can be integral, differential, and / or proportional to the measured difference between the servo-controlled variable and the setpoint. Hence the term "PID compensator," an acronym for "proportional, integral, and differential." Such adjusters are set by gain or coefficient to weight corrective actions that are proportional to the difference, its integral, and its derivative, respectively. Actions that can be described as "proportional" directly contribute to the responsiveness and stability of the servo control. "Integral" actions allow for the elimination of residuals, bringing precision to the system, while "derivative" actions allow for limiting oscillations near the setpoint of the servo-controlled variable.

[0003] Furthermore, depending on the reliability required to constitute a system used in land, sea, air, and / or space transportation, such a servo system may be a multiple redundant system and require multiple devices for mediating such multiple redundancies.

[0004] In engineering, the concept of "redundancy" consists of duplicating important elements or functions of a system for the purpose of increasing the reliability of the system. When the safety of anticipated passengers is at risk, as may occur during aircraft flight, certain parts of an aircraft's control system may be duplicated or tripled, hence the term "dual or triple redundant system" is used. Thus, for example, an error occurring in an element related to element failure or performance drift can be offset or compensated for by one of the other redundant elements or by the use of other redundant elements. Multiple redundant systems are also known as "majority / logic systems" or "voting logic systems" and use the generation of multiple identical variables for purposes such as controlling an actuator.

[0005] There are several modes of operation for multiple redundant servo systems for actuators. Let us take the example of a system for controlling an actuator using three similar servo systems, called "twin systems" or "redundant systems," each generating, i.e., in parallel with each other, variables that must represent exactly the same setpoints. Commands to the actuator are ultimately generated based on one or more variables generated by the redundant systems. According to a first known mode of operation, commands to such an actuator are generated based on variables generated by one of the three servo systems, sometimes referred to as the "primary." Only when it is observed that the primary has failed does the control system or the operator of the control system select a new primary from among these redundant servo systems to replace the previous primary. Such a failure can be detected by a large difference between the variable provided by the primary and the average value of the variables provided by its twins. This solution may not be optimal if the values ​​of the servo control variables generated by each of the redundant servo systems differ. If the three redundant servo systems represent variables with very different values, reassigning the primary system becomes difficult. This is because, if the consensus is not clear among the other redundant systems, it is no longer possible to assess the possible failure or drift of the current primary. Another technique consists of calculating the average of the variables generated by each of the redundant servo systems and generating commands for the actuators based on the average. This second embodiment is problematic at times, particularly when one of the systems provides a variable that takes a very different value from the value generated by its twin. In fact, the resulting average is negatively affected by the strong drift of the faulty system and itself will be very different from a reasonable value for ultimately generating appropriate actuator commands. [Overview of the project]

[0006] The present invention can overcome the drawbacks previously described. Among the many advantages brought about by the implementation of the present invention, the following can be mentioned: namely, - Automatic correction of values ​​generated from servo devices against values ​​generated from twin servo devices in a multiple redundant control system prevents the risk of discrepancies in generated values ​​and enhances their validity. - The distribution within the system to control the arbitration and / or correction of redundant generated values ​​improves reliability without complicating it or hindering the responsiveness of actuator command generation. - Accurate and adaptive correction of redundant generated values ​​regarding the characteristics of the generated signals or data improves the accuracy and validity of the generated commands without burdening responsiveness or increasing the cost and complexity of the system implementing the invention. - The recommendation of a median value that takes into account the generated values ​​from at least three redundant servo devices, and the delays caused by information sharing between the redundant servo devices, provides a reasonable compromise, especially when generating outliers or deviation values.

[0007] To this end, the present invention provides a method implemented by a processing unit of one of several redundant servo devices in a system for controlling an actuator, each redundant servo device generating identical values ​​of a variable based on identical setpoints and identical measurement data, the generated values ​​being used by the system to control the actuator, and the redundant servo devices communicating with each other so that each redundant servo device can access the latest values ​​of the variable generated by the redundant servo device by readout.

[0008] In order to prevent any drift in the generation of each variable value, the method described above, - A step of generating the current variable value based on the set value and measurement data, - A step of reading the latest known value of a variable generated by the redundant servo device of the control system and constructing a set of current values ​​for the variable, - A step of determining the reference value of the variable taken from the set, - A step of calculating the difference between the current value of the generated variable and the reference value, - Iteratively includes the step of correcting the current value and generating a corrected current value of the variable, which consists of subtracting from the current value a correction value resulting from a calculation that multiplies the difference by a correction coefficient for the current value.

[0009] To enhance the validity of the generated variable values, if the control system includes at least three redundant servo devices capable of generating such values ​​for the variable, the step of determining a reference value advantageously comprises selecting the median of the set of current values ​​for the variable.

[0010] In a modified example, if the control system includes only two redundant servo devices capable of generating such values ​​for the variable, the step of determining the reference value may consist of selecting one of the values ​​in the set of current values ​​for the variable.

[0011] The value of the correction coefficient can be predetermined in order to determine the combination of values ​​generated from redundant servo devices.

[0012] In modified examples, such coupling may be dynamic. For this purpose, the method according to the present invention may include the step of recording the current or corrected values ​​of the generated variables in the data memory of the servo device to construct a log of a predetermined number of values. Thus, such a method includes, prior to the correction step, the step of generating a value of a correction coefficient that depends on the variability of the values ​​taken from the log and the repetition frequency of the step of reading the most recent known values ​​of the variables generated by the redundant servo device.

[0013] Furthermore, in order to prevent any sudden corrections, or even to facilitate the process of correcting the generation of variable values, the calculation of the correction value is adjusted so that the absolute value of the correction value does not exceed a predetermined limit.

[0014] According to a preferred embodiment in which the redundant servo device includes a PID corrector that provides three elements of output signals representing proportional operation, integral operation, and derivative operation, respectively, the variable can be composed of the element representing the integral operation of the PID corrector.

[0015] To enhance the reliability of a system for controlling an actuator, it may include a redundant source provided to jointly provide a plurality of set values. The method according to the present invention advantageously provides that the set values are - When the control system includes only two redundant sources, one of the plurality of values is - When the control system includes at least three redundant sources, it may include the step of generating a set value so as to take the median value of the plurality of values as the value.

[0016] To enhance the reliability of a system for controlling an actuator, it may include a redundant source provided to jointly provide a plurality of measured data values. The method according to the present invention advantageously provides that the measured data are - When the control system includes only two redundant sources, one of the plurality of values is - When the control system includes at least three redundant sources, it may include the step of generating measured data so as to take the median value of the plurality of values as the value.

[0017] According to a second aspect, the present invention relates to one of several redundant servo devices of a system for controlling an actuator, wherein the redundant servo devices generate values of exactly the same variables based on exactly the same set values and exactly the same measured data, and the redundant servo devices further communicate with each other such that each servo device accesses the latest value of the variable generated by the redundant servo device by reading. The servo device is provided to implement the method according to the present invention.

[0018] According to the third subject, the present invention relates to a system for controlling an actuator including several redundant servo devices, wherein the actuator command is generated based on multiple values ​​of a variable jointly generated by the redundant servo devices.

[0019] According to an advantageous embodiment, the control system is configured such that the command is -If the plurality of values ​​include only two values, one of the plurality of values ​​of the variable generated by the redundant servo device will be: -If the plurality of values ​​include at least three values, the generated variable may be provided to be generated based on the median of the plurality of values.

[0020] According to the fourth subject matter, the present invention relates to a means of transport having a pilot, passengers, and / or cargo consisting of articles or goods, wherein the means of transport includes one or more actuators in the form of at least one thrust unit for moving the means of transport, and commands to the actuators are generated by a control system according to the present invention.

[0021] In a preferred application, such a means of transport could be an aircraft.

[0022] Furthermore, according to the fifth subject, the present invention relates to a computer program comprising one or more program instructions that can be interpreted by a processing unit of one of a plurality of redundant servo devices in a system for controlling an actuator according to the present invention. For this purpose, the program instructions may be placed in the non-volatile memory of the servo device and designed so that the method according to the present invention is carried out by their execution by the processing unit.

[0023] According to the sixth subject, the present invention relates to a storage medium that can be read by such a processing unit, which includes instructions for such a computer program.

[0024] Other features and advantages can be better understood by reading the following explanation and examining the attached diagram. [Brief explanation of the drawing]

[0025] [Figure 1] Figure 1 shows a first known propulsion system configured to provide substantially vertical takeoff and landing capability. [Figure 2] Figure 2 shows the configuration of a thrust system for a known propulsion device, as shown in Figures 1 and 1A. [Figure 3] Figure 3 shows the configuration of a setting unit that includes a human-machine input interface for translating human commands to pilot an aircraft, as described with reference to the previous figure. [Figure 4] Figure 4 shows an example of a functional architecture for a flight control system intended to be mounted on a drone. [Figure 5] Figure 5 shows an example of a functional architecture of a system according to the present invention for controlling actuators such as aircraft thrust units, which may, in some cases, include multiple redundant flight control devices that may be similar to the flight control devices shown in the previous figure. [Figure 6] Figure 6 shows a functional description of an example of a method for correcting data generated by a servo device in a system for controlling an actuator, as described in Figure 5. [Figure 7] Figure 7 shows the first significant contribution obtained by the implementation of the present invention regarding the generation of pitch actuator commands by the control system according to Figure 5. [Figure 7A] Figure 7A shows a second contribution obtained by the embodiment of the present invention with respect to such pitch actuator commands generated by a control system according to Figure 5. [Figure 8] Figure 8 shows a significant contribution obtained by the implementation of the present invention with respect to roll actuator commands generated by a control system similarly according to Figure 5. [Modes for carrying out the invention]

[0026] The present invention will be described through examples of its application in the field of flight control of aircraft or heavy aircraft, configured in a preferred but non-limiting manner to provide substantially vertical takeoff and landing capability. In non-limiting examples, such propulsion systems may consist of drones, quadcopters, or octocopters. Document EP3495262A1 describes an example of such a propulsion system. However, the present invention is not limited to these applications and may instead be used in relation to any type of device for propelling cargo, pilots, or passengers.

[0027] According to the present invention, such a vertical takeoff and landing aircraft is operated by multiple thrust units. This differs from that taken from document EP3495262A1 in that the operating commands for each of the thrust units are generated by a multiple redundant control system.

[0028] As shown in Figure 1, the aircraft 10 is configured to lift loads transported by the aircraft 10 in accordance with technical instruction taken from document EP3495262A1, and comprises a quadcopter including thruster support means 14, the support means 14 taking the form of four arms forming an "X" on a substantially planar platform 11. Each arm supports thrust systems TSa, TSb, TSc, TSd, each including thrust units 12a, 12b, 12c, 12d, respectively, which consist of turbojet-shaped thermal thrusters. To lift loads transported by the platform 11, not shown in Figure 2, the four thrust units 12a, 12b, 12c, 12d provide thrust vectors AL12a, AL12b, AL12c, AL12d, respectively, substantially perpendicular to the platform 11. To land without damaging the turbojet nozzles or fluid outlets of the thrust units 12a-12d, the arms of the support means 14 for the thrust systems TSa, TSb, TSc, and TSd cooperate advantageously with retractable projection means or legs 17 at their respective end portions. The control system 30, in the form of an electronic processing means, provides thrust commands to the thrust systems TSa, TSb, TSc, and TSd in the form of, for example, PPM (pulse position modulation) signals following modulation techniques known as transmission by "point-to-point" connections, multiple bits of code in a single coded pulse of symbols for 2M possible temporal transitions, or any other suitable format. The fluid outlets of the thrusters of the thrust systems are positioned above or below the height of the center of gravity CG 10 of the device 10, substantially at that height, depending on the configuration and arrangement of the support means 14. To change and stabilize the attitude of platform 11, each thrust system TSa to TSd includes means 19a, 19b, 19c, and 19d for correcting the thrust vectors AL12a, AL12b, AL12c, and AL12d, respectively, provided by the turbojet thrust units 12a to 12d.

[0029] Figure 2 shows the configuration of a means for correcting the thrust vector 19a of the thrust unit 12a of the thrust system TSa according to Figure 1. The means 19a for correcting the thrust vector includes a pair of deflector guides 19a-1 and 19a-5, which are movable and more specifically attached by their respective pivot links 19a-2 and 19a-6. The deflector guides 19a-1 and 19a-5 are positioned to deflect all or part of the thrust vector AL12a in a region close to the fluid outlet 12a-o of the turbojet 12a-e of the thrust unit 12a. Thus, the deflector assembly composed of the deflector guides 19a-1 and 19a-5 can "pinch" the thrust vector AL12a. The deflector guides 19a-1 and 19a-5 are advantageously actuated by a pair of cam actuators or servo motors, respectively. Only actuator 19a-3 of these can be seen in Figure 1. Accordingly, actuator 19a-3 cooperates with deflector guide 19a-1 by control rod 19a-4. The operation of the cam of actuator 19a-3 causes rotational motion r of deflector guide 19a-1 around shaft 19a-2, which is positioned above the fluid discharge area of ​​turbojet 12a. This limits the torque required of actuator 19a-3 to overcome and withstand the suction or discharge generated by the thrust vector AL12a provided by the turbojet 12a-e of thrust unit 12a while the deflector guide 19a-1 is opening and closing. If cam actuators, such as actuator 19a-3, associated with deflector guides 19a-1 and 19a-5 respectively, result in the pinching of the thrust vector AL12a by these deflector guides 19a-1 and 19a-5, the thrust vector AL12a is subdivided downstream of the deflector guide into two or three components AL12a, AL12a', and AL12a'', depending on whether a particular deflector guide 19a-1 or 19a-5 enters the flow discharged at the fluid outlet 12a-o of the turbojet 12a-e. The force of the thrust vector AL12a is maximized in an "open" configuration where the deflector guides 19a-1 and 19a-5 are substantially outside the trajectory of the thrust vector AL12a.Conversely, if one (or both) of the two deflector guides 19a-1 and 19a-5 "sandwich" the thrust vector, the thrust resulting from the thrust vector AL12a is reduced downstream of the deflector guides 19a-1 and 19a-5 until it is canceled out during the "total sandwiching" of the flow from the turbojet injection nozzle outlet 12a-o by the deflector guides 19a-1 and 19a-5. Depending on the design of the deflector guides 19a-1 and 19a-5, in a "closed" arrangement of the two guides 19a-1 and 19a-5, a reverse thrust may be generated, i.e., a thrust vector in the opposite direction to the thrust vector AL12a at the fluid outlet 12a-o. These deflector guides 19a-1 and 19a-5 are analogous in Figure 3 to two substantially curved scoops or semicircular surfaces facing each other. For example, such reverse thrust of about 10 to 30 percent may be possible thanks to the shape of the guide. In fact, these guides may be configured to guide the fluid flow resulting at the exit (end portion) of the guide, respectively, of secondary thrust vectors AL12a' and AL12a'' which are directed substantially opposite in direction to the original thrust vector AL12a at the fluid outlet 12a-o of the turbojet 12a-e.

[0030] In a modified example, the thrust systems TSa to TSd of the aircraft 10 each consist of propellers rotated by an electric engine and / or a thermal engine, and can provide thrust equivalent to that described by a turbojet-based thrust system, as described with reference to Figures 1 and 1A. Regardless of the embodiment of the thrust system of the propulsion device, the electronic control system 30 controls the respective outputs of the thrust systems TSa to TSd based on measurements provided by an inertial navigation system 40 advantageously located near the center of gravity CG10 of the aircraft 10, and flight control setpoints provided by a setpoint unit 20 that communicates with the control system 30 via wired or wireless communication CL. Thus, the control system 30, via the setpoint unit 20, translates pilot instructions into commands to actuators (thrusters, deflectors) to adjust the thrust provided by the thrust systems TSa to TSd, respectively, which result in a trajectory of the aircraft 10 as requested by the pilot, relative to the attitude and position of the aircraft estimated by the measurement unit 40.

[0031] Figure 1A shows such an aircraft 10 considering a reference frame determined by three axes x, y, and z, which are marked in the plane of the platform 11 with respect to the x and y axes, and perpendicular to the x and y axes with respect to the z axis. The three axes x, y, and z intersect at the center of gravity CG10 of the aircraft 10. The x axis extends from the tail to the nose of the aircraft, and the y axis extends from the starboard side to the port side. The z axis represents a vertical line from a distance to the ground when the platform is horizontal. Such an aircraft 10 can move in the air according to rotations R, P, and Y induced around the x, y, and z axes, respectively, by the control system 30 systematically adjusting the respective thrusts provided by the thrust units TSa to TSd. Thus, vertical ascent of the aircraft 10 is induced by a joint and identical increase in the thrusts provided by the four thrust units TSa to TSd, an increase sufficient to produce a lifting force greater than the weight of the aircraft 10. Conversely, the vertical displacement of the aircraft from top to bottom is achieved by the synchronized and identical reduction of thrust provided by four thrust units TSa to TSd, which generate a lifting force less than the weight of the aircraft 10.

[0032] To induce a forward (nose) or rearward (tail) displacement of the aircraft 10, the control system 30 induces a thrust difference between pairs of thrust units, one formed by thrust units TSa and TSd on the one hand, and the other by thrust units TSb and TSc on the other hand. Thus, a rotation P around the y-axis, also known as "pitch," is induced. The relative and combined lift of the pair {TSa, TSd} relative to the pair {TSb, TSC} induced by the positive thrust difference induces a forward displacement of the aircraft. The reverse induces a rearward displacement of the aircraft 10.

[0033] To induce a displacement to port or starboard, the control system 30 induces a thrust difference between pairs of thrust units, one formed by thrust units TSa and TSc on the one hand, and the other by thrust units TSd and TSb on the other hand. Thus, a rotation R around the x-axis, also known as "roll," is induced. The relative and combined lift of the pair {TSa, TSc} relative to the pair {TSb, TSd} induced by the positive thrust difference induces a displacement of the aircraft 10 to port. The opposite induces a displacement of the aircraft 10 to starboard.

[0034] The control system 30 can further induce a Y rotation of the aircraft around the z-axis, also known as "yaw." To this end, the control system 30 induces an asymmetric pinching of the deflector guides of each thrust unit TSa~TSd of at least one pair of thrust units {TSa, TSb} or {TSc, TSd}. Referring to Figure 2, such asymmetric pinching of the deflector guides 19a1, 19a-5 of thrust unit TSa generates three components of thrust produced by the thrust unit. It is oblique to the platform under the combined effect of one of the components AL12a, which is not strictly parallel to the direction of fluid discharge from the turbojet 12a-e, and thus perpendicular to the platform, but remains parallel to the direction of fluid discharge by the turbojet 12a-e, and the dominant component of the components AL12a' or AL12a'', which is substantially perpendicular to it. Depending on whether component AL12a' is greater than or less than component AL12a'', the Y rotation around the y-axis is induced in either a clockwise or counterclockwise direction.

[0035] To ensure that no ascent or descent of altitude is caused during yaw, roll, or pitch, the control system 30 induces an increase equal to the decrease in the combined thrust provided by one or more pairs of thrust units involved by such asymmetric clamping of the deflector guide, so that the overall lifting force provided by all thrust units remains constant.

[0036] As shown in Figure 3, to translate pilot instructions, the setpoint unit 20 may consist of a human-machine input interface including a pair of input peripherals in the form of handles or levers 21 and 22, also known as joysticks. The present invention is not limited to this selection of input peripherals, which may also include, or as a variation, a plurality of buttons, tactile surfaces, or any other equivalent suitable means.

[0037] For example, according to Figures 3 and 3A (Figure 3A shows an overhead view of joysticks 21 and 22), the joystick 21 can detect four displacements D21-1, D21-2, D21-3, and D21-4 of the end portion 21d of the lever 21 relative to its support portion 21b. That is, -Displacement D21-1 may represent a set value from the pilot attempting to increase the aircraft's overall thrust and induce altitude gain. -In contrast to displacement D21-1, displacement D21-2 represents a pilot-set value that reduces the aircraft's overall thrust and can induce a decrease in altitude. -Displacement D21-3 may represent a set value from the pilot to rotate the aircraft 10 counterclockwise around the z-axis in Figure 1A. -In contrast to displacement D21-3, displacement D21-4 may represent a pilot's setting for rotating the aircraft 10 clockwise around the z-axis in Figure 1A.

[0038] Again, as an example, according to Figure 3A, the joystick 22 can detect four displacements D22-1, D22-2, D22-3, and D22-4 of the end portion 22d of the lever 22 relative to its support portion 22b. That is, -Displacement D22-1 may represent a set value from the pilot attempting to induce a forward displacement of the aircraft. -In contrast to displacement D22-1, displacement D22-2 may represent a set value from the pilot attempting to induce a rearward displacement of the aircraft. -Displacement D22-3 may represent a set value from the pilot attempting to induce a port-side displacement of the aircraft. -In contrast to displacement D22-3, displacement D22-4 may represent a setting by the pilot attempting to induce a starboard displacement of the aircraft.

[0039] The setpoint unit 20 also includes one or more electronic means 23, such as a microcontroller or microprocessor, to convert such displacements of the ends 21d and 22d of the levers 21 and 22 into electrical setpoint signals Gsp, which are intended to be transmitted to the control system 30 by a wireless or wired path CL. Such electronic means 23 may be redundant in several ways, and multiple setpoint signals Gsp → They can be jointly generated.

[0040] The setting unit 20 may also include other components, such as push buttons for translating commands to start the thrusters, notifying pilots of loss of capability to ensure aircraft control, or switching from manual control mode to assisted control mode. The electronic means 23 of the setting unit 20 are provided to further communicate the information provided by the components. Thus, the setting unit 20 may send signals Gsp, for example of a PPM type, carrying a vector of information, or, if the means 23 has redundancy, multiple signals Gsp → It can even send data. Within the information vector, examples include the position Xsp setting, the course / yaw ψsp setting, the thruster start or stop setting, and the control mode identifier.

[0041] Figure 4 shows, as far as it is concerned, a system 30 for controlling actuators TS, for example, the thrust units TSa to TSd of aircraft 10 according to Figure 1. The control system 30 integrates with or works with one or more inertial navigation systems 40 (accelerometer, gyroscope, magnetometer), inertial navigation units (INUs), and even inertial measuring units (IMUs). Such measuring units 40 are designed, in particular, to estimate the position X^ and linear velocity V^ or angular velocity Ω^ of aircraft 10. The linear velocity V^ and position X^ can be estimated with respect to a “NED (Northeast Down) coordinate” reference frame. This is determined by three orthogonal axes, with the first axis pointing in the direction of true north, the second axis pointing in the direction of the center of the Earth, and the third axis pointing in the direction of east. The attitude Ψ^ and quaternion q^ of the aircraft, as well as any angular velocity Ω^, are generally estimated with respect to a reference frame specific to aircraft 10, as shown by the x, y, and z axes in Figure 1A. The linear velocity and position may, in some cases, be corrected by a Kalman filter.

[0042] The control system 30 includes one or more flight control devices FCs, whose purpose is to integrate measurements provided by one or more measurement units 40 and control setpoints provided by a setpoint unit 20 to provide commands Δ that can transmit to each thrust unit TSa~TSd (or more generally actuator TS) mainly elements relating to pitch δp, roll δr, yaw δy, and power / thrust δt, for example in the form of PPM signals or equivalents.

[0043] Figure 4 provides a more detailed schematic diagram of the architecture of a flight control system (FC) for an aircraft such as the drone 10 shown in Figure 1. In this example, the flight control system (FC) includes a plurality of control devices comprising two main stages labeled STA and STB in Figure 4. Stage STA is responsible for adjusting the aircraft's position in the NED coordinate system. In the example shown in Figure 4, as a whole, Stage STA generates a set acceleration Asp based on, on the one hand, measurements coming from the measurement unit 40, in this case, estimates of the aircraft's position X^ and linear velocity V^, and on the other hand, position setpoint Xsp provided by the setpoint unit 20 as described above with reference to Figures 3 and 3A.

[0044] The stage STB is responsible, to that extent, for the aircraft's position in a reference frame called the “object coordinate” reference frame, which is specific to the aircraft's platform, as shown by the x, y, and z axes in Figure 1A, and provides actuator command elements Δ for pitch δp, roll δr, and yaw δy based on, on the one hand, a value generated from the step STA (set acceleration Asp) and a course / yaw setpoint ψsp coming from the control unit, and on the other hand, measurements provided by the measurement unit 40 with respect to attitude Ψ^, quaternion q^, and angular velocity Ω^. For this purpose, the interface 33 ensures the substitution of the reference point so that the set acceleration Asp and course / yaw setpoint ψsp are converted into elements δt of the command Δ for the set quaternion qsp and power / thrust.

[0045] Each stage, STA and STB, can be "tuned" according to different periods or frequencies. The frequencies of the tuning performed by the two main stages, STA and STB, may be 50 Hz for stage STA and 250 Hz to 1000 Hz for stage STB.

[0046] According to the example shown in Figure 4, each of the stage STA and STB includes two control devices 31 and 32 with respect to the stage STA, and two control devices 34 and 35 with respect to the stage STB, respectively.

[0047] The device 31 for controlling the aircraft's position provides a set velocity Vsp based on the difference between the set position Xsp and the estimated position X^. The control device 32 then compares this set velocity Vsp with the linear velocity V^ estimated by the measurement unit 40 to generate the set acceleration Asp.

[0048] The device 34 for controlling the attitude of the stage STB provides a set angular velocity Ωsp by comparing a set quaternion qsp with estimates of the quaternion q^ and attitude Ψ^ provided by the measurement unit 40. The device 35 for controlling the angular velocity of the stage STB then compares this set angular velocity Ωsp with the aircraft's angular velocity Ω^ estimated by the measurement unit 40 to ultimately generate components of the control vector Δ with respect to pitch δp, roll δr, and yaw δy.

[0049] Advantageously, the position control device 31 and the attitude control device 34 each generate outputs proportional to the difference between their inputs. On the other hand, the linear velocity and angular velocity control devices 32 and 35 each generate outputs based on elements representing corrective actions proportional to the difference between their inputs, the integral and derivative of the difference, respectively, by using, for example, a PID control device. Each control device may advantageously include its own processing unit Ut (in the form of one or more microprocessors or microcontrollers working with data and / or program memory M) which samples measured values ​​and / or setpoints provided by the measurement unit 40 and / or setpoint unit 20, or more generally by a source that provides setpoints or measurement data, according to a predetermined frequency. Thus, such a source may be called a “setpoint source,” but may consist of the setpoint unit 20 as described above with reference to Figure 3. This is the case for the flight control device 30 if the flight control device 30 is considered as a whole, or for just one position control device 31 of such a flight control device FC. Such a setting source may further consist of a device 31 for controlling position, a device 34 for controlling attitude, and an interface device 33, with respect to the linear velocity control module 31 and the angular velocity control module 35.

[0050] In a modified example, such a flight control system FC may include only one processing unit Ut responsible for implementing generation methods specific to different electronic elements (position control unit 31, attitude control unit 34, linear velocity control unit 32, or angular velocity control unit 35, or interface 33). Regardless of whether the processing unit Ut of the flight control system is centralized or distributed, i.e., whether all or some of the different electronic elements of the flight control system include its own processing unit Ut (Figure 4 shows such a situation for control modules 34 and 35), the operation of the processing unit Ut may be advantageously determined by a suitable computer program, the program instructions of which are placed in one or more data and / or program memories M that cooperate with the processing unit.

[0051] Figure 5 shows an embodiment of such a system 30 for controlling actuator TS according to the present invention, where the measurement, communication, and / or data processing elements are redundant for reliability. In this example, the three flight control devices FC-1, FC-2, and FC-3 are similar to the control devices FC described above with reference to Figure 4, but are located within the control system 30 and perform similar processing based on measurement data coming from the measurement unit 40 and setpoint data provided from the setpoint unit 20. Thus, the three flight control devices FC-1 to FC-3 are each responsible for generating commands Δ1, Δ2, or Δ3 for actuator TS, such as the thrust units TSa to TSd of the aircraft 10 already described with reference to Figure 1. Thus, the commands Δ1, Δ2, or Δ3 collectively control the commands Δ of the control system 30. → It forms.

[0052] Unlike known control systems that have multiple redundancies, i.e., include several flight control devices that independently generate commands Δ1, Δ2, or Δ3 based on measurement data GS and a common setpoint Gsp, the control system 30 according to the present invention is configured such that the commands Δ1, Δ2, and Δ3 are jointly generated by redundant flight control devices. To this end, the three flight control devices FC-1, FC-2, and FC-3 are configured to communicate with each other via a communication bus B so that each flight control device knows the values ​​generated by its twin. More specifically, each control device that produces these values ​​and ensures adjustment of position, attitude, and linear and angular velocity (such as devices 31, 32, 34, and 35 shown in Figure 4) can itself know the data generated by its twin within the different flight control devices FC-1 to FC-3. According to an advantageous embodiment, such a communication bus B may consist of a CAN (Controller Area Network) data bus, which is advantageously redundant, i.e., duplicated for reliability. Such a technical choice is advantageous for transmitting a large amount of data through just one cable and separating it among the different electronic elements of the control system 30.

[0053] Therefore, the outputs or commands Δ1, Δ2, and Δ3 provided by the flight control devices FC-1, FC-2, and FC-3, respectively, can also be generated by these flight control devices not independently of each other, but jointly, i.e., taking into account the values ​​generated from redundant flight control devices. Thus, the commands Δ1, Δ2, and Δ3 can be jointly generated as multiple redundant commands Δ → The commands are formed and transmitted to the actuator TS, more specifically to its electronic control unit, and the control unit of the actuator TS itself may be multiple and redundant. Such a control unit is incorporated into the concept of the actuator for simplicity in Figure 5. Such a control unit and / or actuator TS performs processing for selection and / or arbitration between different commands Δ1, Δ2, and Δ3 to realize its function. As an advantageous example, such a control unit may have multiple commands Δ provided by the control system 30. → Based on this, the "single" command Δ is given, the command Δ is, - If only two of the redundant flight control devices FC-1, FC-2, and FC-3 possess the capability to generate such commands (this situation may occur if one of the three flight control devices fails), then one of the commands Δ1, Δ2, and Δ3 jointly generated by the redundant flight control devices FC-1, FC-2, and FC-3, respectively, -The multiple commands Δ1, Δ2, and Δ3 that are jointly generated by redundant flight control devices → It can be generated such that it is composed of the median of .

[0054] In a modified example, such a control system according to the present invention comprises a plurality of commands Δ1, Δ2, and Δ3 jointly generated by three flight control devices FC-1, FC-2, and FC-3, respectively. → Based on this, the system is configured to directly generate "just one" command Δ, thereby freeing the actuator TS from such arbitration tasks. In this case, such a control system 30 may include arbitration means (not shown in Figure 5 for simplicity) to produce such command Δ in a manner similar to the previously disclosed art for arbitration that the actuator may perform.

[0055] As shown in the example in Figure 5, the measurement unit 40 can be further increased in the form of three redundant measurement units 40-1, 40-2, and 40-3, each providing its measurements to three flight control units FC-1, FC-2, and FC-3. These flight control units FC-1, FC-2, and FC-3 can transmit measurement data provided to their twins via communication bus B by the measurement unit dedicated to each flight control unit. Thus, as shown in the example in Figure 5, measurement unit 40-1 provides measurement data Gs1 to flight control unit FC-1 in the form of estimated values ​​of the aircraft 10's position X1^, linear velocity V1^ and angular velocity Ω1^, its attitude Ψ1^, and quaternion q1^. Similarly, measurement unit 40-2 provides measurement data Gs2 to flight control unit FC-2 in the form of estimated values ​​of the aircraft 10's position X2^, linear velocity V2^, and angular velocity Ω2^, its attitude Ψ2^, and quaternion q2^. Finally, the measurement unit 40-3 provides the flight control device FC-3 with measurement data Gs3 in the form of estimates of the aircraft 10's position V3^, linear velocity V3^ and angular velocity Ω3^, its attitude Ψ3^, and quaternion q3^. In a modified example, the three measurement units 40-1, 40-2, and 40-3 may be connected to the three flight control devices FC-1, FC-2, and FC-3 via a communication bus B.

[0056] Via communication bus B, the setting value unit 20 provides the three flight control devices FC-1, FC-2, and FC-3 with setting values ​​Gsp for position Xsp, course, and yaw ψsp. Such setting values ​​are further provided by multiple Gsp units if the setting value unit has multiple redundancy. → This is possible. Figure 5 further shows the possibility of a navigation support module 20a that, in place of or in addition to the setpoint unit 20, may be supplementary, assist the pilot and provide setpoints Gsp for position Xsp, course and yaw ψsp.

[0057] In an ideal world, the three flight control units FC-1, FC-2, and FC-3 would be completely identical, capable of sampling data or signals transmitted via data bus B at infinite frequencies, and thus immediately sharing their generated data with their twins. The measurement units would provide identical, noise-free estimates as far as they are concerned. According to such an ideal world, there could be no difference or discrepancy between the commands Δ1, Δ2, and Δ3 provided to the actuator TS. However, this ideal world is unrealistic. Therefore, there is a delay between the reading or sampling of data generated by its twin, performed by each flight control unit, and the generation of its own data. In reality, the sampling frequency of data available via communication bus B cannot be unlimited, the measurement data may be noisy and vary depending on the measurement units 40-1, 40-2, and 40-3 under consideration, and the electronics and clocks in each of the redundant flight control units FC-1, FC-2, and FC-3 cannot be made to be exactly the same or synchronized. Consequently, commands Δ1, Δ2, and Δ3 repeatedly deviate from and even differ from each other, losing accuracy and validity, and resulting in disadvantages to aircraft control. To address such realities and / or technical constraints, the present invention provides assigning a method for correcting generated values ​​of variables, taking into account the generated values ​​from the control devices and / or twin flight control devices, in each of the flight control devices FC-1, FC-2, and FC-3 within the control system 30, or even in each of the respective control devices 31, 32, 34, and 35 of the said flight control devices FC-1, FC-2, and FC-3. Thanks to the implementation of such a method according to the present invention, commands Δ1, Δ2, and Δ3 are jointly generated by the flight control devices FC-1, FC-2, and FC-3 and do not differ in planned operation (i.e., according to design constraints), thereby allowing the actuator TS to consider consistent and accurate commands Δ1, Δ2, and Δ3.

[0058] It is important to emphasize that if the control system 30 includes only two redundant flight control units, or if only two of the three flight control units shown in Figure 5 retain their generating capability, it is particularly advantageous that the redundant commands remain consistent and do not instruct each other. In fact, even if actuator TS considers only one of the two commands during its arbitration, if a failure occurs in the flight control unit generating the command that was used up to that point, and actuator TS must then select and use the second command instead of the first command that is no longer available, the actuator will not experience any significant change in control, and therefore in operation. The situation would be quite different if the generation by the two redundant flight control units were to occur in parallel, i.e., independently of each other, and not jointly as in accordance with the present invention. In fact, without the contribution of the present invention, the commands provided by the two redundant flight control units, respectively, could gradually diverge from each other. During command switching, the aircraft's operation would lose continuity. Such correction methods, unique to the present invention, that enable the joint generation of redundant commands, may be implemented by the processing unit of the flight control device FC itself (i.e., centralized) as shown in Figure 4, or by one of the different processing units of the control devices 31, 32, 34, and 35 contained therein (i.e., distributed). Hereinafter, the expression “servo device” will be used indiscriminately to refer to such a flight control device itself or a control device contained therein.

[0059] To adapt the operation of such a servo device, program instructions that can be interpreted by the processing unit of the servo device may be placed in its non-volatile memory M. Therefore, such program instructions are designed so that their execution by the processing unit Ut of such a servo device implements a method for correcting the generation of the value of the variable in question according to the present invention. Such program instructions constitute a computer program itself and may be transmitted or stored on any suitable storage medium.

[0060] Figure 6 shows such a method 100 according to the invention, intended to be implemented by a processing unit Ut of one of several redundant servo devices of a system for controlling an actuator. Advantageously, such a method 100 is provided to be implemented by each of said redundant servo devices. These redundant servo devices are provided to each generate the value of the same variable G based on exactly the same setpoint Gsp and exactly the same measurement data Gs. To generate such a variable jointly, the servo devices communicate with each other via a communication bus B as shown, for example, in Figure 5, whereby each servo device can know, i.e., access, the latest value of the variable G generated by the redundant servo devices via the communication bus B by reading.

[0061] Such a method 100 is repeatedly implemented according to a predetermined frequency SP. As described above, without limiting the invention in any way, such a frequency SP can be selected to be between 50 Hertz and 100 Hertz with respect to the control device of stage STA in the control device FC according to Figure 4, or between 250 Hertz and 1000 Hertz with respect to the control device of stage STB.

[0062] Such a method 100 includes a first step 110 of generating a value Gl of variable G based on setpoint Gsp and measurement data Gs.

[0063] It further includes, for example, via communication bus B, reading the latest value of the variable generated by the redundant servo device, and constructing a set G of the current value of the variable G based on the read and accessed value and the value generated in step 110. → step 120.

[0064] According to a first example of implementation by a system 30 for controlling actuator TS shown in Figure 5, the servo device implementing method 100 may consist of a flight control device FC-1, and twin servo devices of control device FC-1, namely flight control devices FC-2 and FC-3. In this case, the variable G mentioned is the actuator command Δ → The value Gl is command Δ1 if the servo device implementing method 100 is control device FC-1, or command Δ2 if the servo device FC-2 implements method 100 to the extent of it, and the same applies to the twin servo devices of flight control devices FC-1 and FC-3. According to this first example, set G → This consists of commands Δ1, Δ2, and Δ3. The setpoint Gsp consists, as far as it is concerned, of elements relating to position Xsp, trajectory, and yaw ψsp coming from a setpoint unit such as unit 20 in Figure 5. The measurement data Gs consists, as far as it is concerned, of the total estimated values ​​of position X^, linear velocity V^, attitude Ψ^, and quaternion q^, as well as angular velocity Ω^, provided by the measurement unit 40 in Figure 4, and further of the estimated values ​​provided by redundant measurement units 40-1, 40-2, and 40-3, respectively, as shown in the example in Figure 5.

[0065] According to a second example of an implementation of Method 100 according to the present invention, carried out by the control system 30 of actuator TS shown in Figure 5, the redundant servo device implementing Method 100 may be the respective linear velocity controllers 32 of the flight control devices FC-1, FC-2, and FC-3, or even the respective angular velocity controllers 35 of the flight control devices FC-1, FC-2, and FC-3, when the flight control devices FC-1, FC-2, and FC-3 are configured as shown in Figure 4. When the redundant servo device is the linear velocity controller 32, the variable G is the set acceleration Asp, or more specifically, if the velocity controller 32 includes a PID controller, its element representing the integral motion. The set value Gsp consists, as far as it is concerned, of the set linear velocity Vsp, which is itself generated by the position controller of the flight control device FC-1, FC-2, or FC-3. → This consists of a single element of the set acceleration Asp generated by the twin speed control device 32, or the integral operation of the PID control device of the twin speed control device.

[0066] In a modified or additional modification, the redundant servo system for implementing Method 100 according to the present invention may consist of position control devices 31 of flight control devices FC-1, FC-2, and FC-3, respectively. Thus, the variable G under consideration is the set linear velocity Vsp. The set value Gsp consists, as far as it is concerned, of elements relating to position Xsp, course, and yaw ψsp coming from the set value unit 20, and the measured data Gs is the position of the aircraft estimated by the measurement units 40, 40-1, 40-2, and 40-3.

[0067] In order to combine, i.e., jointly generate, variable values ​​with respect to redundant servo devices, it is necessary to correct the values ​​generated in step 110 to take into account the values ​​generated from the redundant or twin servo devices. For this purpose, method 100 according to the present invention further sets G → It is taken from, that is, in step 120, the set G →The process includes step 130, which determines a reference value Gr of the variable selected from the values ​​that form the function.

[0068] Each element of the actuator control system 30 implements the method 100 in a distributed manner, but if the actuator control system 30 includes at least three redundant servo devices (such as control devices FC-1, FC-2, FC-3, or their position, attitude, and / or linear velocity or angular velocity control devices) that can generate and communicate values ​​of the variable G, the present invention relates to the step 130 of determining a reference value Gr, which is a set of the current values ​​of the variable G. → It can be provided that this may consist of determining the median of the aforementioned values ​​that form the set G. → This refers to the midpoint of the set, where 50 percent of the data have values ​​below the median, and 50 percent of the data have values ​​above the median. For small datasets, it is sufficient to count the number of data points and arrange them in increasing order according to their respective values. If the number of data points is odd, it is necessary to increase the number by 1 and divide it by 2 to obtain the rank that represents the median. The rank is given by set G → This is the position of the values ​​when they are ordered. That is, the lowest value corresponds to the first rank, the second lowest to the second rank, and so on. Thus, according to the example of a triple-redundant system, the median would be selected as the value of the second-rank variable, or again as the midpoint between the two minimum and maximum values. By selecting the median, deviations caused by certain prior art that prefer the mean or single selection when the generated value from one of the servo devices is clearly out of sync with all the others can be avoided.

[0069] On the other hand, even if the control system 30 includes only two redundant servo devices, or if only two of the multiple servo devices can still generate the value of the variable G, step 130 for determining the reference value Gr is to set the current value of the variable G G →The process consists of selecting one of the current values ​​of the variable G generated by a first or second servo device that is still capable of generating a value for the variable G. Such selection may be biased towards the servo device having the lowest index number, if the redundant servo devices are identified by index, or according to any other technique that chooses alternating or random selection.

[0070] Next, method 100 includes step 140, which calculates the difference Ge between the current value Gl of the variable G generated in step 110 and the reference value Gr, and step 150, which generates a corrected current value Gl' of the variable G, which consists of performing an operation to subtract a correction value Gc. The correction value Gc consists of the result of a calculation in which the difference Ge is multiplied by a correction coefficient Kc of the current value Gl obtained from step 110. In this way, the final generated value Gl' from each redundant servo device is combined with that of the other redundant servo devices. These redundant servo devices, in effect, jointly generate the corrected value Gl' of the variable G.

[0071] To carry out step 150, which generates a corrected current value Gl' of the variable G, the value of a correction coefficient Kc that induces the combination of the respective generated values ​​from the redundant servo devices is predetermined and can be written, for example, to the memory M of each servo device. The selection of the value of the correction coefficient Kc has different notable technical effects on the operation required of the control system 30, as will be seen later with reference to Figures 7, 7A, and 8. Depending on the variable G under consideration, the value of the correction coefficient Kc may be selected as equal to 1, which means that the entire difference Ge between the current value Gl and the reference value Gr of the variable G generated by one of the redundant servo devices is subtracted from the current value Gl, and it takes the reference value Gr as its value. In a modified example, only a portion of the difference Ge may be subtracted from the current value Gl to generate a corrected value Gl'. Thus, in order to sample the values ​​generated by one or more twin servo devices in step 120, i.e., the set of current values ​​G of the variable G generated by the set of redundant servo devices →To construct this, the correction coefficient value Kc can be empirically selected according to a criterion based on the variability of the variable G with respect to frequency SP. For example, a correction coefficient Kc with a low value of, say, 5 percent would be preferred for a variable G whose value changes significantly with respect to frequency SP, while conversely, a coefficient close to or equal to 100 percent would be preferred in the opposite case. Furthermore, set G → To construct this, it is possible to select a small correction factor Kc when there is a large delay between the current values ​​generated by different redundant servo devices, and a value close to or equal to 100 percent when the opposite is true. Thus, if the variable G is an element representing the integral operation of a PID control device 32 for linear velocity control, it is possible to support Kc values ​​that fall between 80 and 100 percent. In a modified or additional case, if the variable G is an element representing the integral operation of a PID control device 35 for angular velocity control, it is possible to support Kc values ​​that fall between 5 and 30 percent. The present invention will not be limited to these configurations. Thus, in order to exchange the respective generated values ​​from the redundant servo devices, or even the respective repetition frequencies SP of each of these redundant servo devices, the servo device memory M may include a table of possible values ​​for the correction factor Kc corresponding to the variable G, depending on the performance of the communication means B.

[0072] During the design or adjustment phase of the control system, or during the simulation phase of such system 30, a correction value Kc can be predetermined to adjust the technical combined effect obtained by implementing method 100 according to one or more variables G under consideration.

[0073] In a modified example, the value of the correction coefficient Kc is dynamic and can be adjusted in real time by each redundant servo device of the control system. In this case, the present invention provides that such a servo device can estimate the variability by constructing a log of a predetermined number of values ​​of the variable Gl generated in step 110 or the variable Gl' corrected in step 150 in step 151. Thus, before the execution of step 150, or even according to an execution frequency lower than the repetition frequency SP of steps 110, 120, 130, 140, and 150, in step 101, the value of the correction coefficient Kc is an estimate of the variability of the previous value of the variable G, and set G → The adjustment 101 can be dynamically adjusted according to the iteration frequency SP of step 120 in constructing the system. Such adjustment 101 can be determined by a pre-established calculation rule. According to a modification of the embodiment, such adjustment 101 can be performed, for example, through a number of flight simulations, or more generally, by a neural network pre-trained using data collected from servo control of various variables.

[0074] The present invention provides, instead of or in addition to weighting the corrected value Gc by selecting an appropriate correction coefficient Kc for the particular variable G, a method of limiting the corrected value Gc by its absolute value before subtracting it from the value Gl generated in step 110. For this purpose, step 150, which generates the corrected value Gc, may be provided to limit the corrected value Gc by its absolute value to a limit value L. Thus, if the corrected value Gc calculated based on the difference Ge between the current value Gl of the variable G and the reference value Gr exceeds the limit value L in absolute value, the absolute value of the corrected value Gc takes the limit value L as its value. As a non-limiting example, such a value L may be calculated as a percentage of the reference variable Gr that is strictly above 0% and below 30%.

[0075] This dual setting of step 150, using the correction coefficient Kc on the one hand and the limit value L on the other, provides a very clever process for adjusting the operation expected by the actuator TS control system 30 according to the present invention.

[0076] As shown in Figure 5, specific input data for a servo device can be redundant, i.e., originate from multiple sources. This may be the case when measurement data is provided to the servo device by multiple redundant sources, or when, via communication bus B, values ​​generated by similarly redundant third-party servo devices are intentionally injected into the input to the servo device. For example, referring to Figures 4 and 5, the input to the linear velocity servo device 32 may be provided with, on the one hand, estimated values ​​of the aircraft's linear velocity provided by measurement units 40-1, 40-2, and 40-3, and on the other hand, set linear velocities provided by position control devices 31 of different flight control devices FC-1, FC-2, and FC-3, respectively.

[0077] The same may apply to the position control device 31, attitude control device 34, or angular velocity control device 35 of the redundant flight control devices FC-1, FC-2, and FC-3, respectively.

[0078] Therefore, referring to Figure 6, the set value Gsp is a plurality of values ​​Gsp provided by the redundant source that provides the set value of the actuator control system. → When composed of, the method 100 according to the present invention is such that the set value Gsp is - These multiple values ​​Gsp → If it contains only two values, i.e., if only two redundant sources provide such a setting, then one of the plurality of values ​​is - These multiple values ​​Gsp → If the configuration includes at least three values, i.e., at least three redundant sources provide such configurations, then step 102 may include generating the configuration Gsp such that the median of the plurality of values ​​is taken as the value.

[0079] Similarly, step 110 generates a value Gl for the variable G, which includes a set value Gsp and a set of multiple values ​​Gs provided by the redundant sources of the control system (e.g., measurement units 40-1, 40-2, and 40-3 in Figure 5). → When performed based on measurement data Gs consisting of, Method 100 according to the present invention is advantageous if the measurement data Gs is - These multiple values ​​Gs → If the multiple values ​​Gs include only two values, i.e., if only two redundant sources provide the measurement data, → One of them, - These multiple values ​​Gs → If the data includes at least three values, i.e., at least three redundant sources provide such measurement data, step 103 may include generating the measurement data Gs such that the median of the plurality of values ​​is taken as the value.

[0080] Referring to Figures 4 and 5, Figures 7, 7A, and 8 illustrate the different contributions obtained by implementing the present invention and the influence of the selection of the value of the correction coefficient Kc on the operation of the control system according to the present invention. Figures 7 and 8 respectively show two variables G, in this case the command Δ → The elements relating to the pitch δp and roll δr are shown, in particular, the elements of these variables that represent the integral operation of the PID control device of the angular velocity control device 35 as shown in Figure 4.

[0081] Figure 7 shows the command Δ related to pitch δp generated by the flight control devices FC-1, FC-2, and FC-3, respectively. → The elements representing the integral operation of the elements are shown more specifically. Therefore, each generated value related to the pitch δp of the flight control device is -Regarding control device FC-1 (element δp1), the curve has a solid line, -Regarding the control device FC-2 (element δp2), the curve shown by the dotted line is: -It appears in the dashed curve with respect to the control device FC-3 (element δp3).

[0082] Figure 7 shows the respective generated values ​​from the flight control devices FC-1, FC-2, and FC-3 over time t, corresponding to three separate values ​​of the correction coefficient Kc, which are equal to 0, 0.05, and 1, respectively, via three separate graphs. The top graph corresponds to the case where the correction coefficient Kc is zero (Kc=0), i.e., the situation according to the prior art (no correction is performed on the generated values ​​from the flight control devices FC-1, FC-2, and FC-3). The middle graph corresponds to the case where the value of the correction coefficient Kc is equal to 0.05 (Kc=0.05), i.e., the partial combination of the generated values ​​from the flight control devices FC-1, FC-2, and FC-3. Finally, the bottom graph corresponds to the case where the value of the correction coefficient Kc is equal to 1 (Kc=1), i.e., the full combination of the generated values ​​from the flight control devices FC-1, FC-2, and FC-3.

[0083] When the value of the correction factor Kc is 0 (as shown in the top graph of Figure 7), it can be noted that the PID controllers of the servo devices, in this case the angular velocity controllers 35 of the flight control devices FC-1, FC-2, and FC-3, are not coupled. The three curves δp1, δp2, and δp3 show their respective generated values, but the differences are increasing and they fluctuate very significantly. However, the implementation of the present invention results in outstanding technical effects of convergence and consistency of the respective generated values ​​from the flight control devices FC-1, FC-2, and FC-3, as shown in the middle and bottom graphs of Figure 7. Those graphs show three curves δp1, δp2, and δp3 that are nearly identical to the naked eye and show excellent immediate coupling as soon as the correction factor Kc is greater than 0. A very low value, 0.05, as shown in the example in the middle graph of Figure 7, results in a very good coupling, symbolized by the almost perfect overlap of the three curves δp1, δp2, and δp3 (as shown by the partial magnification of the three curves δp1, δp2, and δp3). The same is true for the full coupling obtained by selecting a correction factor Kc value equal to 1. The curves δp1, δp2, and δp3 further overlap completely, which is synonymous with a very strong coupling and perfect coherence, as shown by the partial magnification of the curves δp1, δp2, and δp3. A more detailed examination of the middle and bottom two graphs for correction factor Kc values ​​of 0.05 and 1, respectively, reveals that a correction factor Kc equal to 0.05 maintains a higher responsiveness than the aligned and combined generated values ​​from the three flight control devices FC-1, FC-2, and FC-3 (the slopes of curves δp1, δp2, and δp3 are very steep or vertical at the instant ti in which the system responds to a setpoint that would result in a significant slope in the values ​​of elements δp1, δp2, and δp3). Nevertheless, such responsiveness can be reduced by a larger value of correction factor Kc (in this case, equal to 1 for the bottom graph in Figure 7). The slopes of curves δp1, δp2, and δp3 actually become less vertical at the instant ti.However, the overlapping curves δp1, δp2, and δp3 are smoother or more stable than those represented in the middle graph, and even more so than those shown in the top graph (uncorrected). Therefore, the choice of correction factor value Kc can determine the compromise between the desired responsiveness and stability. This effect on responsiveness and stability is more accurately illustrated by Figure 7A, which shows three curves representing the value of only one element related to the pitch δp1 generated by the flight control device FC-1 for three different values ​​of the correction factor Kc. As a curve with a solid line for the Kc value of -0 (K=0), The dotted line represents the curve for a Kc value equal to -0.05 (K=0.05), The curve is superimposed as a dashed line for Kc values ​​equal to -1 (K=1).

[0084] Figure 7A shows the tangents tg0, tg1, and tg2 of the three δp1 curves described above (for Kc=0, Kc=0.05, and Kc=1, respectively) at the moment ti when the system responds to a setpoint that would result in a significant slope of the value of the element δp1. The tangent tg0 is nearly vertical and shown as a solid line, indicating the very high responsiveness of the control system when there is no coupling with the respective generated values ​​from the redundant flight control devices FC-2 and FC-3 (Kc=0). The tangent tg1 is shown as a dotted line, but still represents the very high responsiveness of the control system during weak coupling (Kc=0.05). In fact, the angle α1 is determined by the tangents tg0 and tg1, but has a small value, indicating a slight decrease in responsiveness. The tangent tg2 is shown as a dashed line, and represents the responsiveness of the control system during strong coupling (Kc=1). The angle α2, determined by the tangents tg0 and tg2, is significantly larger than the angle α1, indicating a lower response.

[0085] However, Figure 7A shows that stability is provided, presumably at the expense of reduced responsiveness. Thus, the average amplitude of the variation of the element δp1 is very large (as shown by line segment A0 in Figure 7), which is synonymous with instability, but as soon as the present invention obtains coupling between the respective generated values ​​from redundant flight control devices, such an average amplitude shown by line segment A1 becomes very small, even if it is at its minimum (a correction factor value Kc = 0.05), or the average amplitude even becomes nearly zero, as shown by line segment A2, which shows the average amplitude for a strong coupling (Kc = 1).

[0086] Other generated values ​​from the three flight control systems FC-1, FC-2, and FC-3, in this case the command Δ for roll δr. → When the present invention is implemented to combine elements representing the integral operation of the PID control device of the angular velocity control device 35 related to the elements, by observing Figure 8, one can note the outstanding similar contribution obtained by the present invention.

[0087] In fact, Figure 8 shows the generated values ​​for the pitch δp command generated by the flight control devices FC-1, FC-2, and FC-3, respectively. These are, -With respect to the control device FC-1 (element δr1), the curve has a solid line, -Regarding the control device FC-2 (element δr2), the curve shown by the dotted line is: -It appears as a dashed curve with respect to the control device FC-3 (element δr3).

[0088] Similar to Figure 7, Figure 8 shows the respective generated values ​​from the flight control devices FC-1, FC-2, and FC-3 over time t, corresponding to three separate values ​​of the correction coefficient Kc equal to 0, 0.05, and 1, respectively, through three separate graphs located at the top, middle, and bottom of Figure 8. The top graph corresponds to the case where the correction coefficient Kc is zero, i.e., the situation according to the prior art (no correction is performed on the generated values ​​from the flight control devices FC-1, FC-2, and FC-3). The middle graph corresponds to the case where the value of the correction coefficient Kc is equal to 0.05, i.e., a partial combination of the generated values ​​from the flight control devices FC-1, FC-2, and FC-3. Finally, the bottom graph corresponds to the case where the value of the correction coefficient Kc is equal to 1, i.e., a full combination of the generated values ​​from the flight control devices FC-1, FC-2, and FC-3.

[0089] When the value of the correction factor Kc is 0 (as shown in the top graph of Figure 8), it can be noted that the PID controllers of the servo devices, in this case the angular velocity controllers 35 of the flight control devices FC-1, FC-2, and FC-3, are not coupled. The three curves δr1, δr2, and δr3 show their respective generated values, but the differences increase and they fluctuate very significantly. Conversely, in the implementation of the present invention, as soon as the correction factor Kc is greater than 0, immediate coupling is shown. A very low value, 0.05, as shown in the example in the middle graph of Figure 8, results in almost perfect overlap of the three curves δr1, δr2, and δr3. The same is true for the full coupling obtained by selecting a correction factor Kc value equal to 1. The curves δr1, δr2, and δr3 overlap perfectly, which is synonymous with very strong coupling and strong bonding. A more detailed examination of the middle and bottom two graphs for correction factor Kc values ​​of 0.05 and 1, respectively, reveals that a correction factor Kc value equal to 0.05 maintains higher responsiveness than the consistent generated values ​​from the three flight control systems FC-1, FC-2, and FC-3. Indeed, the slopes of curves δr1, δr2, and δr3 are very steep or vertical at the moment tj when the system responds to a setpoint that would result in a significant slope in the values ​​of the elements δr1, δr2, or δr3. However, when considering the values ​​of elements δr1, δr2, and δr3 resulting from a larger correction factor Kc (in this case, equal to 1 for the bottom graph in Figure 8), such slopes become less vertical. Conversely, the overlapping curves are smoother or more stable than those represented by the middle graph. Figure 8 thus confirms that the choice of correction factor value Kc can determine the compromise between the desired responsiveness and stability of the system.

[0090] The present invention has been described by various configurations of systems for controlling actuators, more specifically, aircraft thrust units. The present invention is not limited to this one example of a system for controlling actuators. More generally, it relates to any control system including one or more multiple redundant servo devices applied to home automation, industrial, or land, sea, air, or space transport means, in an attempt to enable the actuators to move, or to enable the adjustment of their internal temperature, atmosphere, or brightness.

Claims

1. A method (100) performed by a processing unit of one of several redundant servo devices (FC-1, FC-2, FC-3) of a system (30) for controlling an actuator (TS), wherein each redundant servo device generates identical values ​​of a variable (G) based on identical setpoints (Gsp) and identical measurement data (Gs), the generated values ​​are used by the system (30) to control the actuator (TS), the redundant servo devices (FC-1, FC-2, FC-3) communicate with each other so that each redundant servo device can access the latest value of the variable (G) generated by the redundant servo device by reading, and the method is Step (110) of generating the current value (Gl) of the variable (G) based on the set value (Gsp) and the measurement data (Gs), The latest value of the variable (G) generated by the redundant servo device is read, and the current value of the variable (G) is set (G → The steps (120) to construct, The aforementioned set (G → The steps (130) include determining the reference value (Gr) of the variable (G) taken from, Step (140) of calculating the difference (Ge) between the current value (Gl) and the reference value (Gr) of the generated variable (G), A method (SP) characterized by iteratively including (SP) a step (150) of correcting the current value (Gl) and generating a corrected current value (Gl') of the variable (G), which consists of subtracting a corrected value (Gc) resulting from a calculation of multiplying the difference (Ge) by a correction coefficient (Kc) of the current value (Gl) from the current value (Gl).

2. The system includes at least three redundant servo devices capable of generating the value of the variable (G), The step (130) of determining the reference value (Gr) is to determine the set (G) of the current value of the variable (G). → The method according to claim 1 (100), comprising selecting the median value of ).

3. The system includes only two redundant servo devices capable of generating the value of the variable (G), The step (130) of determining the reference value (Gr) is to determine the set (G) of the current value of the variable (G). → The method according to claim 1 (100), comprising selecting one of the values ​​of ).

4. The method according to any one of claims 1 to 3 (100), wherein the value of the correction coefficient (Kc) is predetermined.

5. A method (100) according to any one of claims 1 to 3, comprising: (151) recording the current value (Gl) or corrected value (Gl') of the variable (G) in the data memory (M) of the first servo device to construct a log of a predetermined number of values; and (101) before the correction step (150) generating a value of the correction coefficient (Kc) that depends on the variability of the values ​​taken from the log and the repetition frequency (SP) of the step (120) of reading the latest value of the variable (G) generated by the redundant servo device.

6. The method according to any one of claims 1 to 3 (100), wherein the calculation of the correction value (Gc) is adjusted so that the absolute value of the correction value (Gc) does not exceed a predetermined limit value (L).

7. The method according to any one of claims 1 to 3 (100), wherein the redundant servo device each includes a PID corrector that provides three elements of an output signal representing proportional, integral, and differential operation, and the variable (G) is composed of the element representing the integral operation of the PID corrector.

8. The control system (30) sets a plurality of set values ​​(Gsp → If the set value (Gsp) includes a redundant source provided to jointly provide the above, If the control system (30) includes only two redundant sources, the plurality of values ​​(Gsp → ) one of them, If the control system has at least three redundant sources, the plurality of values ​​(Gsp → The method according to any one of claims 1 to 3 (100), comprising the step (102) of generating the setting value (Gsp) such that the median of ) is taken as the value.

9. The control system (30) controls the measurement data (Gs → If the measurement data (Gs) includes a redundant source provided to jointly provide multiple values ​​of ), When the control system includes only two redundant sources, one of the plurality of values (Gs → ) If the control system includes at least three redundant sources, the plurality of values ​​(Gs → The method according to any one of claims 1 to 3 (100), comprising the step (103) of generating the measurement data (Gs) such that the median of ) is taken as the value.

10. A servo device for a system (30) for controlling an actuator (TS), wherein the system (30) has exactly the same set value (Gsp, Gsp → A servo device comprising a plurality of redundant servo devices (FC-1, FC-2, FC-3) that each generate identical variable values ​​(Δ1, Δ2, Δ3) based on identical measurement data (Gs1, Gs2, Gs3), wherein the redundant servo devices (FC-1, FC-2, FC-3) communicate with each other so that each servo device can access the latest values ​​(Δ1, Δ2, Δ3) of the variables generated by the redundant servo devices by reading (B), and the servo devices (FC-1, FC-2, FC-3) are provided to carry out the method (100) according to any one of claims 1 to 3.

11. A control system (30) for an actuator (TS) including a plurality of redundant servo devices (FC-1, FC-2, FC-3) as described in claim 10, wherein the command (Δ → A system in which Δ1, Δ2, Δ3) are generated based on multiple values ​​of the variable jointly generated by the redundant servo device.

12. The aforementioned command (Δ) is, The plurality of values ​​(Δ → If Δ1, Δ2, Δ3) contains only two values, the plurality of values ​​of the variable (Δ) generated by the redundant servo device → , one of Δ1, Δ2, Δ3, The plurality of values ​​(Δ → If Δ1, Δ2, Δ3) includes at least three values, then the plurality of values ​​of the variable (Δ) generated by the redundant servo device are considered to be → The system (30) according to claim 11, which is generated based on the median of Δ1, Δ2, and Δ3.

13. A means of transport (10) for a pilot, passengers, and / or cargo consisting of articles or goods, comprising one or more actuators in the form of at least one thrust unit (TSa, TSb, TSc, TSd) for moving the means of transport (10), and a command (Δ → Δ) is generated by the control system (30) according to claim 12, the transport means (10).

14. A transport means (10) according to claim 13, comprising an aircraft (10).

15. A computer program comprising one or more program instructions that can be interpreted by a processing unit (Ut) of one of a plurality of redundant servo devices (FC-1, FC-2, FC-3) of a system (30) for controlling actuators (TS), wherein the program instructions are stored in the non-volatile memory (M) of the servo device and can be designed so that the execution of the instructions by the processing unit (Ut) carries out the method (100) according to any one of claims 1 to 3.

16. A computer-readable storage medium comprising the instructions of the computer program described in claim 15.

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