Actuator for operating a device of an aircraft

Abstract

Actuator for actuating a device of an aircraft with at least two non-contact sensors, characterized in that at least one of the sensors is arranged in the load path of the actuator and at least one of the sensors is arranged outside the load path of the actuator.

Description

The invention relates to an actuator for actuating a device of an aircraft, in particular of an aircraft, having at least two non-contact-operating sensors. The invention is also directed to an aircraft with a corresponding actuator, but applications in the field of traffic technology are also possible.Actuators of aircraft are known from the prior art, which serve for moving or actuating devices of the aircraft. It is known to perform state monitoring of the actuator, for example for position, speed and / or force regulation of the actuator, wherein it is furthermore known to record corresponding data for electrohydraulic servo actuators (EHSA), electro hydrostatic actuators (EHA / EBHA) and electromechanical actuators (EMA) within predefined safety limits by recording the position or the force and / or torque in, for example, the primary flight control of an aircraft or the traffic technology.A first known method for measuring torque on rotating parts is a simple torsion bar. If a shaft is axially twisted, then a rotation angle occurs which is proportional to the applied torsion torque. This angle can be measured with an inductive angle measuring system. The supply voltage of the measuring system and the measuring signal are transmitted via a transformer rotary transformer.However, due to the amplitude-modulated measurement signal, this system reacts very sensitively to axial and radial displacement, out-of-round running, change in the magnetic material properties and to magnetic shunt elements. Considerable measurement errors can thereby occur. Interference variables, such as e.g. the temperature expansion, can be compensated for first, if at all, in the measurement amplifier, so that a temperature behavior of the measurement signal is always to be expected.The use of strain gauge or DMS torque sensors is also known for measuring a torque. The supply voltage and the output voltage are transmitted with the aid of slip rings to the DMS measuring strip mounted on the shaft. The mounting of the slip rings requires some care since they must be insulated from both the shaft and from each other. The contact pressure of the sliding contacts must also be exactly the same in order to prevent excessive heating or lifting.Disadvantages of this measuring technique are, in particular, the measurement errors with even slight insulation errors, the rapid wear of the slip rings and the carbon brushes and the resulting limited circumferential speed. This method was improved by the slip ring-free transmission of the measurement signals. By supplying the DMS bridge with alternating voltage, an amplitude-modulated alternating voltage proportional to the torque is obtained as the output signal. The supply voltage and the measurement signal are transmitted via transformer rotary transformers. With the further development of DMS technology, nowadays the DMS sensors can be manufactured to compensate for temperature as well as to compensate for creep.This enables direct compensation of the disturbance variables. The electronics becoming smaller and smaller and the associated improvement in the measurement accuracy make DMS torque measurement technology nowadays the standard measurement technology. However, this technique also entails many disadvantages. The torque cannot be measured at any desired point, the adhesion of the measuring strips is released in the event of sudden load changes (for example during braking), and transmission problems through the antennas occur again and again.In some cases, torque sensors which operate on the principle of the differential transformer are more suitable than DMS sensors. They consist of a torsion shaft on which a plurality of coils are arranged. Starting from one coil, a voltage is induced in the other coils. The amount of induced voltage depends on the position of the coils relative to each other. The position of the coils in turn depends on the torque applied and represents the angle (angle of rotation) by which the torsion body is rotated over a certain length. A coil is displaced from the original position due to twisting, and thus the induction / coupling changes.Within the primary flight control and the applications as listed below, the position, force and / or torque measurement can usually only be implemented with restrictions.WO 2010 / 016 829 A1 discloses an improved design for a force gradient that uses a proximity sensor. A force gradient includes a shaft having a first end and a second end. The switch includes a spring disposed between the first and second ends and a contactless proximity sensor mounted on the second end. The spring has a first position and is compressed to a second position such that the contactless proximity sensor signals an AFCS to change state.WO 2015 / 078 724 A1 discloses a device for determining a mechanical force of an actuator on a movable aircraft component. The device comprises a shaft, in particular a solid or hollow shaft, for transmitting force and / or torque to the actuator, wherein the shaft has a first remanently magnetized region magnetized in a first circumferential direction; and at least one first magnetic field sensor for detecting a change in the field direction of the first magnetized region occurring under the action of force and / or torque on the shaft.US 4 474 060 A discloses a torque sensor for mounting to a bolted connection between an aircraft brake assembly and a brake reaction torque limiting device to sense the reaction torque upon application of a braking action, comprising a metal body replacing a bushing on the bolted connection and configured to achieve deflection of the body in the direction of the reaction torque force, and at least one pair of strain gauges are attached to the body at the point of deflection to provide an electrical output signal calibrated to the amount of deflection and thus to the reaction torque experienced by the body.U.S. Pat. No. 7,969,110 B2 discloses an actuator having a (auto)synchronous rotating electric motor and a reversible reduction gear which is coupled to the motor in order to be set in rotation by the latter. An output shaft is coupled to the reduction gear to be rotated thereby. A first angular position sensor and a control circuit are connected to the motor. The circuit provides a motor supply signal which varies in response to a position command signal applied to the control circuit and in response to signals provided from the angular position sensor. The transmission includes a plurality of reduction gears each having a pair of gears mounted to rotate about two parallel axes of rotation.Since the methods and apparatuses known today have the technical and commercial disadvantages mentioned, it is the object of the invention to provide an improved apparatus which is in particular less susceptible to faults than the known apparatuses.This object is achieved according to the invention by an actuator having the features of claim 1. Advantageous embodiments are the subject of the dependent claims. Accordingly, an actuator is provided with at least one contactless operating sensor which is arranged in the load path of the actuator. The term "contactless" can refer in the present case to a state in which the sensor and a component detected by the sensor do not have to be in direct, physical contact with one another for the purpose of detecting the sensor. Rather, for example, an air gap may be present between the sensor and the component. The case is also included here in which only a part of the sensor is arranged in the load path and another part of the sensor is arranged outside the load path.By means of the sensor and on the basis of the contactless detection of position, force and / or torques, it is possible to provide methods or algorithms, in particular for electrohydraulic, servo, electro hydrostatic and / or electro mechanical actuators, which make it possible to determine reliably and without wear a. the occurrence of a fault on the device (monitoring), e.g. to predict changing friction, play or rigidity b. the occurrence of a fault on the device (HM) c. to limit the loads occurring in the system or d. to provide information for control circuits such as a force control-in particular the compensation / reduction of a force figureIn contrast to the conventional hydraulic actuators normally used in primary flight control, a higher clamping probability (cases a. and b.) applies to electromechanical drives. Clamping of an actuator must be virtually eliminated. A good possibility of avoiding a clamping situation is provided by monitoring the actuator state.In the case of a plurality of actively switched actuators on a control surface (e.g. Rudder, Aileron, Elevator), force conflicts can be compensated or reduced by the actuators and within the structure by the active regulation of the actuator forces (case c).By detecting the force which the actuator (predominantly electromechanically) subjects to the structure, active monitoring / limiting of this force can be used to protect the structure in the normal operating case and also in special fault cases (case d).In a preferred embodiment of the invention, it is conceivable that at least two linear sections of the sensor are provided which are arranged in particular parallel to one another and differ at least by the extent of different widths in the longitudinal direction. By means of two or more linear sections, it is possible to divide, for example, a magnetic component of the sensor finely in a defined manner. This fine subdivision of the magnetic component can be read out by means of a further component, in particular a read-out component, of the sensor and can be used, inter alia, for determining the above-mentioned parameters or values.According to the invention, it is provided that at least two non-contact-operating sensors are provided, one of which is arranged outside the load path of the actuator. The sensor arranged outside the load path can be used here for detecting reference values, by means of which the detected actuator parameters can be corrected or detected more precisely.In a further preferred embodiment, it is conceivable that a control / regulating device is provided which is configured for state monitoring, for force monitoring for structural protection and / or for avoiding / reducing force conflicts by means of at least one sensor. By means of the control / regulation device, functions for health monitoring, wear analysis, load analysis, maintenance of the actuator and / or for monitoring force conflicts of redundantly designed actuators can thus be carried out.In a further preferred embodiment, it is conceivable that the at least one sensor is configured to perform magnetoresistive measurements.In a further preferred embodiment, it is conceivable that the control / regulating device is configured to perform measurements and / or derivatives of the physical quantities load, torque, position and / or speed of the actuator and / or to access values of the physical quantities load, torque, position and / or speed of the actuator.In a further preferred embodiment, it is conceivable that the sensor is set up outside the load path for temperature compensation.In a further preferred embodiment, it is further conceivable that the sensor is at least partially incorporated into the actuator by means of in particular high-precision magnetic field injection and / or is designed as at least one striction band.By incorporating or embossing the sensor or parts of the sensor, such as the linear section, into components of the actuator or by forming the sensor or parts of the sensor as a tightening band, it is possible to provide parts of the sensor in almost any positions on the actuator and thus, if appropriate, to select positions which are particularly protected, for example by their internal arrangement.In a further preferred embodiment, it is conceivable that the impressed magnetic field and / or the striction band are arranged in a region which goes beyond the region to be measured. The term impressed magnetic field is not to be understood here as restrictive and comprises magnetic fields which are produced in any desired manner. The region of the actuator to be measured relates to a region in which measurements can be made by means of the sensor. The sensor or the impressed magnetic field or the striction band and thus the corresponding part of the sensor can thus extend over a larger region than the measured or the region of the actuator detected or measured by the sensor. This makes it possible to ensure the accurate performance of measurements within the region to be measured particularly easily.It is conceivable that a plurality of sensors are arranged either in the load path or outside the load path of the actuator.In an arrangement outside the load path, there is the advantage that no compensation of the measured values is required for compensating the deformations occurring as a result of the load transmission. The control or regulation of the actuator can be carried out accordingly in a simplified manner.In a further preferred embodiment, it is further conceivable that the device is at least one elevator, one rudder, one rudder, one spoiler, one main rotor adjustment or one tail rotor adjustment.In a further preferred embodiment, it is conceivable that the actuator is an actuator for actuating, steering or locking the chassis and / or that the actuator is an actuator for traffic technology applications.It can furthermore be provided that a primary component of the sensor is arranged on a piston rod and / or rotary shaft and / or on a first housing part of the actuator and / or that a secondary component of the sensor is arranged on a second housing part of the actuator or vice versa. The primary component can be, for example, a pickup or a component for measuring a magnetic field or for detecting the change in a magnetic field, while the secondary component can be an impression of a magnetic field and / or a striction band mentioned further above. The term housing part is also to be interpreted broadly and can comprise any components of the actuator that are not moved in contrast to a piston rod or rotary shaft. In an embodiment as a piston-cylinder device, in which the cylinder is at least partially fixed relative to the aircraft, the cylinder of the device can be the corresponding housing part, for example.In a further preferred embodiment, it is conceivable that the sensor comprises a plurality of, in particular parallel arranged, striction bands, and / or that two or more sensors are arranged in different or identical inertial systems of the actuator.The term inertial systems in the present case means systems or sections of the actuator which are movable relative to one another in particular during the usual operation of the actuator. With a larger number of the striction bands, it is possible to refine the resolution of the sensor. More details of this are given in the description of the figures.In a further preferred embodiment, it is conceivable that the actuator is an EHSA, EHA, EBHA or an EMA.The invention is further directed to an aircraft, in particular an aircraft, having at least one actuator according to one of claims 1 to 13.The invention is also directed to a corresponding method for actuating the actuator according to one of claims 1 to 13, comprising at least one non-contact sensor arranged in the load path of the actuator and at least one sensor arranged outside the load path of the actuator. The method comprises the step of:Temperature compensation by means of the sensor arranged outside the load path.Further details and advantages of the invention are evident from the embodiments shown by way of example in the figures. The following are shown: FIG. 1 : Striction bands in an EHSA in the push rod for position measurement FIG. 2 : Striction bands in a rotational EMA; FIG. 3 : sensor arrangement for temperature-compensated force measurement; FIG. 4 : phase shift of a striction modulation under movement; FIG. 5 : Striction bands for combined position and force measurement; FIG. 6 : combined torsion angle and torque measurement; FIG. 7 : load measurement, play measurement and / or rigidity measurement on a linear EMA; FIG. 8 : Backlash measurement in a rotational EMA; FIGS. 9.1-9.3 show different pressure measurements or load measurements at a hydraulic load cylinder; FIG. 10 : partial view of an aircraft according to the invention.Depending on the accuracy to be achieved, the desired resolution of the sensor measurement is achieved, for example, by using a plurality of striction bands or magnetic components. These bands may have different modulations and provide a unique position signal over the entire stroke of the actuator. For this purpose, the beginning and end of the modulation can be placed outside the range to be measured.In particular, in the case of linear position measurement, the length of the primary sensor under load can change, which can necessitate load compensation. This load compensation can optionally be effected via three different methods: 1. calculating back the period change of the striction modulation using the current position signals of a plurality of striction bands with known period ratios. 2. time measurement of a single striction period with fast movement over a known stroke. 3. when available by means of the load signal and the modulus of elasticity or shear of the material. For combined load and position measurement, the following is given in more detail below.The tightening bands expand not only with the load but also with the temperature of the substrate material. The basis for the temperature compensation is comparable to the bridge circuit of the DMS principle and / or can be effected by a reference measurement outside the load path (cf. with temperature compensation in the force measurement according to FIG. 3 ). This only detects the component expansion due to the temperature fluctuation.If the primary and secondary sensors are placed in different inertial systems (e.g. one sensor on the housing, another on the piston rod or rotary shaft), a Doppler effect is additionally produced during the measurement, e.g. at high running speeds and low carrier frequencies. The necessary compensation can easily be calculated from the speed of travel, wavelengths and frequencies:Withλ B Measured wavelength at secondary sensorλ S wavelength of the striction modulation at the primary sensorv s Running speed of push rodf s Effective carrier frequency at the primary sensorIf a reference sensor is used and the respective primary and secondary components of the measurement and reference sensors are placed in the same inertial system (see FIG. 3 ), this conversion is superfluous.In classic EHSA, the position sensor can be placed on or in the push rod or the cylinder housing independently of the load. In this case, a linear coding of the primary sensor can be present.A measurement of the running speed can also be carried out. In the rotational arrangement, the position measurement lies in the load path and must be compensated. In this case, a rotational coding of the primary sensor can be present.In load measurement, two types of loads are distinguished: force and torsion torque.In the Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Force measurement at in particular linear actuators (EHSA, EHA, EBHA, linear EMA) the force sensor can be placed on or in the cylinder housing or on or in the push rod independently of position. Embodiment 1 (see FIG. 3 ) is preferred, since the sensor itself is not moved and thus the additional risk of possible damage (e.g. cable breakage due to fatigue) or interference due to the movement of the sensor components is avoided. In embodiments with two sensors in different inertial systems on the movable push rod, the evaluation takes into account both: 1. the variable signal phase (see FIG. 4 ) optionally by using a position signal or a plurality of striction bands, and 2. the Doppler effect described further above on the detected signal period.In the combined load and position measurement or, in particular, the force and stroke measurement, the position measurement can be made more flexible using the load evaluation. On the one hand, the position can still be carried out outside the load path and, on the other hand, combined with the load measurement. In this case, a modulation period can be selected for the load compensation and / or a temperature compensation can be carried out separately.A backlash measurement can be performed after a load direction change by comparing the input position with the output position when a second no-load state is reached. If no perfect load-free conditions are available, the strain produced from the stiffness and the load can be subtracted from the position difference in order to achieve a better accuracy.A measurement of stiffness can be carried out, similar to the game measurement, by comparing the input and output positions, but at different loads and with the load direction remaining the same. Alternatively, the rigidity can also be evaluated when a load direction change occurs after the removal of the play.Force measurement can be performed by taking the difference between individual chamber pressure measurements. The respective chamber pressure measurements are carried out on the basis of the elastic circumferential expansion of two independent magnetic strength fields, as can be seen from FIG. 9.1.Alternatively or additionally, a force measurement can be carried out by determining the chamber pressure difference, wherein the chamber pressure difference is detected on the basis of the elastic circumferential extension of a magnetic stress field, which extension changes over the length of the cylinder, distributed over the entire cylinder length. The striction field or the magnetic component can accordingly extend over the entire cylinder length or actuator length or over a substantial portion of the cylinder longitudinal side or the actuator longitudinal side. This is illustrated in FIG. 9.2.Force measurement may also be performed by determining the chamber pressure difference, wherein the chamber pressure measurements are made from the elastic circumferential strain of a magnetic stress field on the pressure chamber end walls. By using a secondary sensor on each cylinder chamber, the relative difference in expansion of the chambers with respect to each other can be determined. This is illustrated in FIG. 9.3.One possible field of application for the actuator can extend to the physical actuation systems including actuating drives of the following devices:Flight controls such as elevators, cross-controllers, rudders, roll spoilers, ground spoilers, main rotor adjustment (or the like) or tail rotor adjustment (or the like).By means of the contactless detection of positions, force and / or torques possible by means of the present invention, relevant signals for a. state monitoring (health monitoring) b. force monitoring for structure protection (limitation / deactivation) c. avoidance / reduction of force conflicts (force FIG. compensation) of electromechanical actuators in their environment (structure) can be used or generated in a significantly more accurate, simpler and wear-free manner in the special use within the primary flight control.The position, force and / or torque information is relevant signals for the realization of simple and robust state monitoring. In particular, the wear estimation and fatigue stress recording require reliable load recording.In particular, the force and / or torque information is used as a shutdown or limitation function for actuators as used in the aforementioned fields of application. As a result, possible damage to the actuators and / or the aircraft structure can be monitored, detected and avoided.In the case of a plurality of active actuators on a control surface (see FIG. 10 ), precise information of the forces and moments occurring at the actuators or at the structure is a basic prerequisite for reliable and rapid force compensation. In the ideal case, actuators and structural parts can thereby be optimized with regard to weight and size on account of lower force flows.By using the novel sensor principle and optionally the reliable production process (e.g. high-precision magnetic field impression), novel sensors and / or actuator components or actuators can be generated, treated and / or used. Due to the contactless and thus wear-free transmission of the signals, line systems (primary, secondary cabling) can possibly be avoided centrally in the device or integrated with the actuator. In addition, the new integration possibilities of the sensors in the equipment make them optimally protected from the air-vehicle-specific, harsh environmental influences (sand, dust, icing, electromagnetic interference). These new contactless, wear-free and thus low-maintenance sensor signals or sensor components represent a basic prerequisite for: A) being able to increase the service life of electromechanical actuators in the primary and / or secondary flight control B) being able to install the new sensors in a highly integrated manner (no LRU need, sensor access and exchangeability) C) being able to provide highly accurate sensor signals (force, torque and position) protected by environmental influences (sand, dust, icing, electromagnetic interference) to the control circuits and algorithms and be able to evaluate them D) being able to enable a 2-in1 combination and thus possibly to save a previously additional, independent sensor (the sensor can be designed to provide a signal combination (2in1) of force, E) to ensure reliable and robust actuator control F) to ensure reliable and robust health monitoringIn order to be able to use and offer robust health monitoring (HM), verified algorithms and long-term stable sensor signals are required. The accuracy and robustness of the HM algorithms are directly dependent on the sensors used and their installation position. The novel contactless, low-wear and highly accurate detection of signal variables relevant in terms of regulation, such as force, torque and position, enables a reliable and robust health monitoring concept.The contactless transmission enables new sensor installation positions (high integration). The new installation possibilities increase the accuracy and quality of the sensor signals (e.g. complete positioning and force detection in the force path) on the one hand and thus also enable new technical application possibilities. Due to the high integration of the contactless signal detection, the sensors are protected, among other things, from environmental influences such as dust, dirt, ice and electromagnetic radiation. Due to the high integration and the resulting indirect protection of the sensors, the electronic protective circuitry of the sensor can be greatly minimized and thus miniaturized.A further innovation consists in combining the sensor signals. The new contactless sensors allow, among other things, a 3in1 combination (e.g. torque position and speed). The new possibility of the 3in1combination assists the efforts to further improve the reliability and availability of the actuators. This also results in a cost, weight and volume optimization.FIG. 1 shows an exemplary embodiment of an actuator according to the invention for actuating a device of an aircraft, in particular of an aircraft, wherein an embodiment is shown in which the sensor is arranged in a push rod or within a push rod of a cylinder-piston device. The sensor can be provided independently of load in a region of the push rod which does not serve for the transmission of force between the push rod and the cylinder housing. A magnetic component or a striction band of the sensor can be designed to be movable together with the push rod. The magnetic component or the striction band further comprises five linear sections in the embodiment of FIG. 1, which can be arranged in particular parallel to one another. The linear sections have subsections which comprise south poles and north poles arranged alternately next to one another. FIG. 2 further shows an embodiment in which the magnetic component or the striction band is provided on a rotary EMA. FIG. 5 shows embodiments of the invention in which striction bands for combined position and force measurement are arranged in particular in the circumferential direction of the actuator, which is designed, for example, as a cylinder-piston device. FIG. 6 shows an embodiment in which a primary sensor is arranged in the circumferential direction of an actuator designed as a rotary actuator. FIGS. 7 and 8 show embodiments of the invention which are configured for game measurement on a linear or rotary EMA. A primary sensor can also be arranged in the circumferential direction of the actuator.The electronics required for adjusting the signals output by the sensor can be arranged on the actuator and / or on a computer separate therefrom. The device can be used to determine limit values and / or trend curves, from which information about the state of life or wear of the actuator can be derived. In this case, positions or force influences and / or delta positions in or outside the load path of the actuator can be measured. The load measurement can preferably be carried out via a torque measurement and in particular via a magnetoresistive measurement.

Claims

Actuator for actuating a device of an aircraft having at least two non-contact-operating sensors, characterized in that at least one of the sensors is arranged in the load path of the actuator and at least one of the sensors is arranged outside the load path of the actuator.Actuator according to Claim 1, characterized in that a control / regulating device is provided which is designed for state monitoring, for force monitoring for structural protection and / or for avoiding / reducing force conflicts by means of at least one sensor.Actuator according to one of the preceding claims, characterized in that the at least one sensor is configured to carry out magnetoresistive measurements.Actuator according to Claim 2 or 3, characterized in that the open-loop / closed-loop control device is configured to carry out measurements and / or derivatives of the physical variables load, torque, position and / or speed of the actuator and / or to access values of the physical variables load, torque, position and / or speed of the actuator.Actuator according to one of the preceding claims, characterized in that the sensor is set up outside the load path for temperature compensation.Actuator according to one of the preceding claims, characterized in that the sensor is worked into the actuator at least partially by means of, in particular, high-precision magnetic field impression and / or is designed as at least one striction band.Actuator according to Claim 6, characterized in that the impressed magnetic field and / or the striction band are arranged in a region which goes beyond the region to be measured.Actuator according to one of the preceding claims, characterized in that the device is in each case at least one elevator, one rudder, one rudder, one roller spoiler, one ground spoiler, one main rotor adjustment or one tail rotor adjustment.Actuator according to one of the preceding claims, characterized in that the actuator is an actuator for actuating, steering or locking the chassis.Actuator according to one of the preceding claims, characterized in that the actuator is an actuator for traffic engineering applications.Actuator according to one of the preceding claims, characterized in that a primary component of the sensor is arranged on a piston rod and / or rotary shaft and / or on a first housing part of the actuator and / or in that a secondary component of the sensor is arranged on a second housing part of the actuator or vice versa.Actuator according to one of the preceding claims, characterized in that the sensor comprises a plurality of, in particular parallel, fixing bands, and / or in that two or more sensors are arranged in different or identical inertial systems of the actuator.Actuator according to one of the preceding claims, characterized in that the actuator is an EHSA, EHA, EBHA or an EMA.Aircraft having at least one actuator according to one of Claims 1 to 13.Method for actuating the actuator according to one of Claims 1 to 13, having at least one non-contact-operating sensor which is arranged in the load path of the actuator, and at least one sensor which is arranged outside the load path of the actuator, comprising the step of: temperature compensation by means of the sensor arranged outside the load path.

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