DE102023104855A1 - Method for controlling an electric actuator of an aircraft - Google Patents

Abstract

The present invention relates to a method for controlling an electric actuator of an aircraft, wherein the actuator has a motor and is operated in a holding mode, wherein the actuator is controlled such that the actuator is controlled to a position and/or load value, wherein the actuator is further controlled such that the position and/or load value is changed within a defined range and/or at least one further parameter of the actuator is controlled and/or changed.

Description

The present invention relates to a method for controlling an electric actuator of an aircraft, wherein the actuator has a motor and is operated in a holding mode, wherein the actuator is controlled such that the actuator is controlled to a position and/or load value.

The trend of electrification of elements, functions and actuators in aviation, through the use of linear and rotary electro-mechanical / electro-hydraulic actuators, continues to advance. The advantages of electrification are realized, among other things, through more efficient and optimized control.

The increased development and use of electrically operated actuators, the wide variety of technical applications, the increased service life requirements and the latest safety requirements for actuators also result in new requirements for the control, safety and monitoring concepts for future electrical actuators, which can be designed as electromechanical actuators (EMA) or as electrohydraulic actuators (EHA).

Future applications within electric flight of the future will place new demands on the equipment. Criteria such as installation space, volume, weight, availability, testability and safe flying are the challenges of the future.

Due to the constantly increasing availability and service life requirements of the actuators, the more complex applications and control loop requirements as well as the new official safety requirements (e.g. regular function monitoring through integrity checks), new requirements arise for the regulations of the applications such as EMA and EHA.

Currently, electrically operated actuators are mostly used as a "backup solution". Classic controllers and control concepts such as cascade controllers are often used for this purpose. The electrification of the function as a backup sometimes requires only a "low" availability of the equipment. In addition, the functional "back-up requirements" do not result in any direct requirements for permanent active control over long periods of time or the entire aircraft life (e.g. 30 years, 180,000 FH, MBTF, 35,000 FC).

Currently, electrically operated actuators, elements or devices are also used as an "active/passive solution". Classic controllers and control concepts such as cascade controllers are often used for this. The electrification of the function as a hybrid or purely electric solution sometimes requires only a "low" availability of the equipment. In addition, the functional "active/passive requirements" do not result in any direct requirements for permanent active control over long periods of time or over the entire life of the aircraft (e.g. 30 years, 180,000 FH MBTF, 35,000 FC).

Within these active/passive applications, an element is electrically operated for a “short time” (e.g. slat/flap during landing approach) and a braking or locking element is activated when a position and/or setting is reached. After the position is reached, the electrically operated main line of the element/actuator is passivated or switched off again.

The electrification of applications in aviation continues to advance. Based on the previously known "back-up" and "active/passive applications", there is an increasing need for permanently powered and actively controlled applications over the entire flight cycle or the life of the aircraft.

The state-of-the-art control systems do not meet the high service life requirements in the permanently powered "active" case. The sometimes highly dynamic classic control in the electrical "back-up case" results in mechanical and thermal damage (e.g. due to internal control oscillation), which can lead to fretting or brinelling and thermal damage.

Permanently active or permanently powered linear and/or rotary electrically operated actuators are confronted with short strokes or micro-oscillation movements depending on the application and area of use. These oscillating micro-movements are not trivial to solve in terms of the mechanical material and lubricant requirements as well as in terms of the surface finish and influence or limit the availability or reduce the life of the actuators through mechanical damage (e.g. fretting, brinelling) and thus cause premature failure of the device. Thermal stress effects due to the necessary permanent control/power supply of the device and/or electronic subcomponents, in conjunction with internal control effects and possible micro-movements due to external loads and forces, must also be taken into account.

Against this background, the present invention is based on the object of developing an above-mentioned method in such a way that the service life of actuators in aircraft is increased, especially during continuous operation.

This object is achieved by the method having the features of the independent claims. Advantageous developments of the invention are the subject of the dependent claims.

According to the invention, it is therefore provided that the actuator is further controlled such that the position and/or load value is changed within a defined range and/or at least one further parameter of the actuator is controlled and/or changed.

Preferably, load is understood to mean a linear force and/or a rotary torque and load control is understood to mean the control of a linear force and/or a rotary torque.

The motor is preferably an electric motor.

In an advantageous embodiment, it is provided that the further parameter is a current and/or a movement of the motor and/or the actuator, wherein the current and/or the movement of the motor and/or the actuator are kept in a defined range, preferably at zero.

Preferably, it is provided that the holding current of the motor and/or the actuator required for the holding operation is regulated such that a torque calculated from the holding current corresponds to a breakaway torque of the motor and/or the actuator.

In an advantageous embodiment, it is provided that a breakaway torque is determined from a current, position information and/or load information of the motor and/or the actuator.

Preferably, the breakaway torque is calculated continuously and/or by a calibration process.

In an advantageous embodiment, it is provided that by reaching a variable to be controlled in a control window and/or by reaching a position in a position window and/or by reaching a load in a load window, it is recognized that the actuator is in a holding mode.

In an advantageous embodiment, it is provided that the position and/or load value is changed within a defined range if a temperature of the motor and/or electronics exceeds a critical value.

Preferably, the actuator is continuously monitored in the sense of condition monitoring and/or health monitoring.

In an advantageous embodiment, it is provided that plausibility checks are carried out on the basis of calibration information, a sensor feedback signal and a calculated control variable, preferably during power-up or continuously, in the sense of regular sensor monitoring and/or calculation comparisons.

It is conceivable that the actuator is an electromechanical or an electrohydraulic actuator.

The invention also relates to a system with means designed such that a method according to the invention can be carried out.

Preferably, the system comprises a lifetime optimization unit which is designed to carry out one of the method steps of a method according to the invention.

The invention also relates to an aircraft, in particular an airplane, with a system according to the invention.

• - vorzugsweise der thermische Stress der betroffenen Komponenten (Endstufe, Kabel, Motor) im Stillstands- bzw. im Minimalregelabweichungsfall deutlich reduziert wird;
• - vorzugsweise die Verfügbarkeit der Aktuatoren durch intelligente Regelung im Sinne der Reduzierung/Vermeidung von Mikrobewegungen (intern & extern) erhöht wird;
• - vorzugsweise die Verfügbarkeit der Aktuatoren durch intelligente Regelung im Sinne einer Reduzierung von thermischen Dauerstress (Wärme bzw. Hitze) durch intelligente (Wechsel-)Regelung erhöht wird;

Preferably, permanently energized, electrically operated actuators can be optimized in their control so that the method according to the invention:

• - preferably the thermal stress of the affected components (power amplifier, cable, motor) is significantly reduced in the case of standstill or in the case of minimal control deviation;
• - preferably the availability of the actuators is increased through intelligent control in the sense of reducing/avoiding micro-movements (internal &external);
• - preferably the availability of the actuators is increased by intelligent control in the sense of a reduction of permanent thermal stress (warmth or heat) by intelligent (alternating) control;

Preferably, the method comprises a lifetime-optimized current, speed, load and/or position control with application-specific intelligent, motor current-optimized, load-dependent motor holding current control (Id_opt, Iq_opt), deadband-optimized actuator control to avoid internally generated micro-movements to increase the lifetime (n_opt; M_opt) and/or opti Optimized thermal motor sector (vector) control to avoid local hot spots of electronic components (power electronics, motor) and increase service life.

Preferably, the EMA actively applies holding loads with an electric motor, whereby the necessary holding current and movement of the electric motor is minimized.

Preferably, the required current in the holding state is reduced to a value that corresponds to the breakaway torque.

Preferably, it is provided that a breakaway current is determined from a motor current, position information of the electric motor and the EMA.

Preferably, it is provided that a breakaway current is determined from load information, position information of the electric motor and the EMA as well as from a motor current.

Preferably, the breakaway torque is calculated continuously.

Preferably, the breakaway torque is calculated by a calibration process.

Preferably, to avoid micro-movements in the actuator - caused by internal control deviations - the motor specification parameters are regulated to "zero" within defined parameters in the "Target Area Zero Hold". After a defined control difference/control window is exceeded, the control is preferably reactivated or controlled with specific control parameters.

Preferably, the motor movement is kept at zero in the holding state.

Preferably, the hold state is detected when a variable to be controlled has reached a control window.

Preferably, the stop state is detected when a position window is reached.

Preferably, the holding state is detected when a load window is reached.

In the event of a thermally critical situation in the electronics and/or the electric motor, the electric motor can leave its original holding state (within defined sectors) by monitoring temperature sensors and minimize its holding position and thus its thermally critical heat input. By making targeted position changes (within defined sectors), the thermal stress on the affected components in the electric motor and electronics can be reduced and the life and availability of the application can be increased.

Preferably, the holding state is changed when the local temperature in the electric motor and/or in the electronics is exceeded, in such a way that the new position generates local heating at another location.

Preferably, the health status of the EMA is continuously monitored in the sense of condition monitoring and/or health monitoring.

Preferably, it is provided that so-called plausibility checks (power-up, continuous) can be carried out on the basis of the available calibration information, the sensor feedback signals and the calculated control variables in the sense of regular sensor monitoring and/or calculation comparisons.

The invention advantageously allows actuator control of EMAs and EHAs that is optimized for service life and availability by avoiding and/or reducing and/or optimizing mechanical short-stroke movements. The invention advantageously allows actuator control of EMAs and EHAs that is optimized for service life and availability by avoiding and/or reducing and/or optimizing and/or changing the thermal energy input (thermal stress) in the control/power electronics, the cables and the motor phases.

The invention advantageously allows a lifetime- and availability-optimized actuator control of EMAs and EHAs by avoiding and/or reducing and/or optimizing sensors through specific measurement and calibration of actuator-specific characteristics (e.g. stiffness values, motor parameters, sensor parameters) and their storage or permanent storage in e.g. non-volatile electronic memory components.

The invention advantageously allows a service life and availability optimized actuator control of EMAs and EHAs by avoiding and/or reducing and/or optimizing early error messages in the sense of improved condition or health monitoring, possible through regular function, integration rity and/or “plausibility checks” in the “Pre-Flight/P-BIT” and “Continuous Check/C-BIT” and by reading the data during service checks on the ground.

At this point, it should be noted that the terms "a" and "an" do not necessarily refer to exactly one of the elements, although this is a possible embodiment, but can also refer to a plurality of the elements. Likewise, the use of the plural also includes the presence of the element in question in the singular and, conversely, the singular also includes several of the elements in question. Furthermore, all features of the invention described herein can be combined with one another as desired or claimed in isolation from one another.

• 1: ein Blockschaltbild von Komponenten einer ersten Ausführungsform eines erfindungsgemäßen Systems.
• 2: ein Blockschaltbild einer ersten Ausführungsform eines erfindungsgemäßen Verfahrens.
• 3: ein Diagramm von Parametern eines Motors eines Aktuators eines erfindungsgemäßen Systems.
• 4: ein Blockschaltbild von drei Ausführungsform eines erfindungsgemäßen Systems.

Further advantages, features and effects of the present invention will become apparent from the following description of preferred embodiments with reference to the figures in which identical or similar components or elements are designated by the same reference numerals.

• 1 : a block diagram of components of a first embodiment of a system according to the invention.
• 2 : a block diagram of a first embodiment of a method according to the invention.
• 3 : a diagram of parameters of a motor of an actuator of a system according to the invention.
• 4 : a block diagram of three embodiments of a system according to the invention.

The use of EMAs (linear and rotary) in specific permanently controlled flight control applications (e.g. spoilers) is controlled by means of superimposed control loops. The EMA(s) must therefore generally be controlled to a holding force or holding load and/or position.

Such a superimposed control loop is 1 The system areas FCC, ECU/COM and EMA, which are represented by the blocks in 1 represented include the components arranged within the blocks.

To control the EMA or the EHA, the motor current sensors, the motor position signal or the motor position information and/or the actuator load sensor (load/torque) are used for control. In an extended application and under certain conditions, a load sensor can be dispensed with.

2 shows the control process with the addition of a life-time optimized controller 1 for electrically permanently actively controlled actuators (linear and/or rotary). The focus here is on a current-optimized holding state, a speed/torque-optimized holding position and the possibility of thermal stress relief/heat dissipation through micro-movements on the motor.

After the start step S1, the actuator is activated by a position command in step S2. In step S3, the actuator is controlled to a position, a speed and/or a current. In step S4, the position of the actuator is requested. If a certain position is reached, controller 1 is activated in step S5. In step S6, a position and/or current-optimized active hold is enabled. In step S7, a new position command is issued. The new position command is preferably issued under the condition that there is no or only minimal movement at the output or the actuator position.

3 shows a diagram with the speed of a motor of an actuator plotted on the abscissa and the current and torque of the motor plotted on the ordinate.

After the permanently active actuator has reached the target position, as in 3 The available information position, load, speed, current (command and feedback signal) is evaluated intelligently so that the EMA, which applies the active holding loads and the necessary holding current IHOLD and the movement of the electric motor n are minimized. The current and/or the torque of the motor are in the area known as the "Target Area Zero Hold".

It can be provided that the required current in the holding state IHOLD is reduced to a value that corresponds to the breakaway torque TBO.

It can be provided that a breakaway current IBO is determined from the motor current IFeedback, the position information of the motor nFeedback and the actuator PosFeedback.

It can be provided that a breakaway current IBO is determined from the load information TFeedback, the position information of the electric motor nFeedback and the actuator PosFeedback as well as the motor current Ix.

It may be provided that the breakaway torque TBO is calculated continuously.

It can be provided that the breakaway torque TBO is calculated by a calibration process.

To avoid micro-movements in the actuator - caused by internal control deviations - the motor specification parameters can be set to "zero" within defined parameters in the "Target Area Zero Hold". After a defined control difference/control window is exceeded, the control can be reactivated or controlled with specific control parameters.

It can be provided that the motor movement is held at zero in the hold state or in the “Target Area Zero Hold”.

It can be provided that the hold state is detected when the variable to be controlled has reached a control window ΔI.

It can be provided that the stop state is detected when a position window ΔPos is reached.

It can be provided that the holding state is detected when a load window ΔF is reached.

In the event of a thermally critical situation (electronics and/or motor), the motor can leave its original stop state (within defined sectors) by monitoring the temperature sensors and minimize its stop position and thus its thermally critical heat input. By making targeted position changes (within defined sectors), the thermal stress on the affected components in the motor and electronics can be reduced and the life and availability of the application can be increased.

It can be provided that the holding state is changed when the local temperature in the motor TempMotor and/or the electronics TempElekr is exceeded, in such a way that the new position generates local heating at another location.

4 shows possibilities and options regarding the physical location for the implementation of controller 1 or the life optimizer. Depending on the actuator/element implementation, controller 1 can be used in variable positions. Examples of aviation applications are, for example, electronics as part of the actuator, electronics near the actuator and electronics away from the actuator (HDDS, SSJ).

• In Beispiel B) befindet sich der Regler 1 vor dem Aktuatorregelkreis 2.
• In Beispiel C) befindet sich der Regler 1 innerhalb des Aktuatorregelkreises 2.
• In Beispiel A) werden die Drehzahl- und/oder Drehmoment-Kommandosignale des übergeordneten Regelkreises werden durch den Regler 1 manipuliert.
• In Beispiel B) werden die Positions- und/oder Last-Kommandosignale werden durch den Regler 1 manipuliert
• In Beispiel C) ist der Life Optimizer 1 integraler Bestandteil der Regelstruktur: z.B. Regelgröße Zustandsreglers oder Cost function in einem Model-Predictive-Control-Regler.

In 4 Three examples A), B) and C) are shown for the position of controller 1. In example A), controller 1 is located between actuator control loop 2 and actuator 3.

• In example B), controller 1 is located before actuator control loop 2.
• In example C), controller 1 is located within actuator control loop 2.
• In example A), the speed and/or torque command signals of the higher-level control loop are manipulated by controller 1.
• In example B), the position and/or load command signals are manipulated by controller 1
• In example C), the Life Optimizer 1 is an integral part of the control structure: e.g. controlled variable of a state controller or cost function in a model predictive control controller.

Claims (12)

Method for controlling an electric actuator of an aircraft, wherein the actuator has a motor and is operated in a holding mode, wherein the actuator is controlled such that the actuator is controlled to a position and/or load value, characterized in that the actuator is further controlled such that the position and/or load value is changed within a defined range and/or at least one further parameter of the actuator is controlled and/or changed. Procedure according to Claim 1 , characterized in that the further parameter is a current and/or a movement of the motor and/or the actuator, wherein the current and/or the movement of the motor and/or the actuator are kept in a defined range, preferably at zero. Procedure according to Claim 1 or 2 , characterized in that the holding current of the motor and/or the actuator required for the holding operation is regulated such that a torque calculated from the holding current corresponds to a breakaway torque of the motor and/or the actuator. Method according to one of the preceding claims, characterized in that a breakaway torque is determined from a current, position information and/or load information of the motor and/or the actuator. Method according to one of the Claims 3 or 4 , characterized in that the breakaway torque is calculated continuously and/or by a calibration process. Method according to one of the preceding claims, characterized in that by reaching a variable to be controlled in a control window and/or by reaching a position in a position window and/or by reaching a load in a load window, it is recognized that the actuator is in a holding mode. Method according to one of the preceding claims, characterized in that the position and/or load value is changed within a defined range when a temperature of the motor and/or electronics exceeds a critical value. Method according to one of the preceding claims, characterized in that the actuator is continuously monitored in the sense of condition monitoring and/or health monitoring. Method according to one of the preceding claims, characterized in that the actuator is an electromechanical or an electrohydraulic actuator. System with means designed such that a method according to one of the preceding claims can be carried out. System according to Claim 10 , characterized in that the system comprises a lifetime optimization unit which is designed to carry out one of the method steps of a method according to one of the Claims 1 until 9 to be carried out. Aircraft, in particular airplane, with a system according to one of the Claims 10 until 11 .

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