METHOD AND APPARATUS FOR CONDUCTING HEALTH MONITORING

Abstract

A health monitoring method for checking a functionality of a flight control surface driving apparatus using a load sensor for sensing a load imposed on a control surface drive device by: blocking movement of the transmission device with a brake device, commanding the control surface drive device to apply a load on the blocked transmission device, and determining whether a load sensor output signal of the load sensor is within a predetermined range. Also, a flight control surface drive apparatus, a flight control system and an aircraft.

Claims

1.-15. (canceled)

16. A method for checking a functionality of a flight control surface driving apparatus comprising a control surface drive device for generating mechanical power for moving at least one control surface, a transmission device for transmitting mechanical power from the control surface drive device to the at least one control surface, at least one brake device or braking movement of the transmission device, at least one load sensor for sensing a load imposed on the control surface drive device, and a control device configured to receive a load sensor output signal from the at least one load sensor and to control the control surface drive device in response to the load sensor output signal, wherein the method comprises: automatically checking proper functionality of at least one of the at least one load sensor and the transmission device by: a) blocking movement of the transmission device with the brake device, b) commanding the control surface drive device to apply a load on the blocked transmission device, and c) determining whether at least one load sensor output signal of the at least one load sensor is within a predetermined range.

17. The method according to claim 16, wherein step b) comprises at least one or several of: b1) sending a load command signal to the control surface drive device corresponding a commanded load to be applied; b2) commanding the control surface drive device to apply a rising load on the blocked transmission device; b3) commanding a closed-loop controller, configured to control a speed and load of the control surface drive device by a close-loop control, to drive the control surface drive device with a predetermined speed and automatically generating load command signals commanding rising loads by the close-loop controller; and, any combination thereof.

18. The method according to claim 16, wherein step c) comprises at least one or several of: c1) determining whether a difference between the load of b) and a load corresponding to the at least one load sensor output signal exceeds a predetermined maximum value; c2) setting the predetermined range depending on a load command signal; c3) ending the determination of c1) when the commanded load signal achieves a predetermined load limit; c4) ending the determination when the at least one load sensor output signal achieves a predetermined load limit of a load limiting function of the flight control surface driving apparatus; c5) determining whether a load command signal generated in step b) is within a predetermined range; and, any combination thereof.

19. The method according to claim 16, wherein the flight control surface driving apparatus to be monitored comprises at least one rotating element for transmitting mechanical power to the at least one control surface, wherein the at least one load sensor is at least one torque sensor determining a torque on the rotating element.

20. An apparatus for driving a flight control surface, the apparatus comprising: a control surface drive device for generating mechanical power for moving at least one control surface, a transmission device for transmitting mechanical power from the control surface drive device to the at least one control surface, at least one brake device for braking movement of the transmission device, at least one load sensor for sensing a load imposed on the control surface drive device, and a control device configured to receive a load sensor output signal from the at least one load sensor and to control the control surface drive device in response to the load sensor output signal, the control device being configured to automatically check proper functionality of at least one of the at least one load sensor and the transmission device by: a) blocking movement of the transmission device with the brake device, b) commanding the control surface drive device to apply a load on the blocked transmission device, and c) determining whether at least one load sensor output signal of the at least one load sensor is within a predetermined range.

21. The apparatus of claim 20, wherein the control surface drive device comprises at least one rotating output shaft, and the at least one load sensor comprises at least one torque sensor for sensing a torque of the rotating output shaft.

22. The apparatus of claim 20, wherein the control surface drive device includes an electric motor controlled by a close-loop controller with regard to speed and torque, wherein the close-loop controller is configured to send a torque command signal commanding gradually rising torque when an output of the electric motor is blocked, wherein the control device is configured to compare the output of the at least one load sensor with the torque command signal.

23. The apparatus of claim 20, wherein the brake device comprises left-hand and right-hand wing tip brakes acting on an output element of the transmission device arranged near a wing tip.

24. A flight control system for an aircraft, the flight control system comprising: at least one flight control surface, and the apparatus according to claim 20 configured to drive the movement of the at least one flight control surface.

25. The flight control system according to claim 24, wherein the at least one control surface comprises a high-lift device.

26. The flight control system according to claim 24, further comprising: a first load sensor for sensing the load imposed on the control surface drive device and a first controller receiving a load sensor output signal of the first load sensor and controlling the movement of the at least one control surface in response to the load sensor output signal of the first load sensor, and, a second load sensor for sensing the load imposed on the control surface drive device and a second controller receiving a load sensor output signal of the second load sensor and controlling the movement of the at least one control surface in response to the load sensor output signal of the second load sensor.

27. The flight control system according to claim 24, wherein the control device is configured to compare the load sensor output signal of the at least one load sensor with a predetermined maximum load value in a flight and ground condition and to trigger, when the load sensor output exceeds the predetermined maximum load value, a reverse movement and a subsequent load control sequence for controlling the load to achieve a lower load level.

28. An aircraft comprising: the flight control system according to claim 24.

29. A non-transitory computer readable media storing a computer program comprising instructions to cause a flight control system to execute the method of claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Preferred embodiments of the invention are explained below with reference to the drawings in which:

[0069] FIG. 1 depicts an embodiment of an aircraft;

[0070] FIG. 2 depicts an embodiment of a part of a flight control system of the aircraft;

[0071] FIG. 3 shows a graph with a load command signal and an output signal of load sensor of the flight control system during a health monitoring procedure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072] Referring to FIG. 1, an aircraft 10 has a flight control system 100 including control surfaces 102 and a flight control surface driving apparatus 104. The flight control surface driving apparatus 104 comprises a control surface drive device 106 for generating mechanical power for the movement of at least one of the control surfaces 102, a transmission device 108 for transmitting mechanical power from the control surface drive device 106 to the at least one of the control surfaces 102, at least one load sensor 110 for sensing a load imposed on the control surface drive device 106, and a control device 112 configured to receive a load sensor output signal from the at least one load sensor 110 and to control the control surface drive device 106 in response to the load sensor output signal. In the embodiment shown, the flight control system 100 includes a high lift system 114 with high-lift devices 18 as control surfaces 102. Several flight control surface driving apparatuses 104, 104s, 104f are configured to drive associated groups of such high-lift devices 18. The flight control surface driving apparatus 104 further includes a brake device 118 for braking or blocking movement of the transmission device 108.

[0073] As further shown in FIG. 1, the aircraft 10 has a fuselage 12. The aircraft 10 also has a pair of wings 14a, 14b that are attached to the fuselage 12. The aircraft 10 further comprises engines 16 that are attached to the wings 14a, 14b.

[0074] The aircraft 10 has a plurality of said high-lift devices 18, such as slats 20 and flaps 22 which are examples of the control surfaces 102. The high-lift devices 18 are driven by a power control unit or PCU 24 which is an example of the control surface drive device 106. The PCU 24 outputs torque to the transmission device 108 which includes drive shafts 25 that are connected to the high-lift devices 18 in a manner known per se. In order to arrest the high-lift devices 18 in a predetermined position, wing tip brakes (WTB) 26a, 26b (elements of the brake device 118) are arranged near the end portions of the drive shafts 25.

[0075] In more detail, the high-lift system 114 includes, as flight control surface driving apparatuses 104, a slat driving apparatus 104s for driving the slats 20 and a flap driving apparatus 104f for driving the flaps. Each of these driving apparatuses 104s, 104f has a centralized PCU 24 mounted in the fuselage. Each PCU 24 is controlled by the control device 112 which includes a first and a second slat flap computer (SFCC) 32-1, 32-2. The first and second slat flap computers 32-1, 32-2 are independent from each other and control and monitor the slat and flap driving apparatuses 104s, 104f in correspondence with the pilot's operation of an input device 34.

[0076] The configurations of the slat and flap driving apparatuses 104s, 104f are similar and are explained in more detail with reference to the example of the slat driving apparatus 104s depicted schematically in FIG. 2.

[0077] Referring now to FIG. 2, first the PCU 24 as an example of the control surface drive device 106 for generating mechanical power for the movement of the slats 20 is described. The PCU 24 has at least two independent motors 36, 38 which are connected by an appropriate gear, for example a speed summing differential gear (DIFG) 40.

[0078] The DIFG 40 has a left-hand output shaft 42a for driving first to seventh left-hand slats 20.1a to 20.7b and a right-hand output shaft 42b for driving first to seventh right-hand slats 20.1b to 20.7b. Of course, the number of slats 20 may differ in other embodiments.

[0079] Each motor 36, 38 is provided with a Power Off Brake 44 to arrest the motor 36, 38 in the commanded position. Depending on the aircraft power supply system and the availability requirements the PCU 24 is either purely hydraulically or electrically driven or includes an electric motor 36 and a hydraulic motor 38 (hybrid PCU) as shown in the present embodiment. For the electric motor 36, a digitally controlled brushless DC motor may be used and for the hydraulic motor 38 a digitally controlled variable displacement motor may be used and may be controlled by a hydraulic valve block 46. For the electric drive embodying the electric motor 36, a Motor Control Electronic (MCE) 48 is interfacing with the SFCC 32-1, 32-2 and an aircraft electrical busbar 50-1, 50-2. The MCE 48 converts the electric power as required for the brushless DC motor. A motor control for the hydraulic and electric drive is established by a closed loop layout to maintain speed and torque command inputs. The control algorithms are implemented, e.g. by software as computer programs, in the control device 112 (e.g. in each SFCC 32-1, 32-2) which is provided with all required data to control the motors 36, 38. The SFCCs 32-1, 32-2 of the control device 112 control this operation of the flight control surface driving apparatus 104 also in response to output signals of load sensors 110 and position pick-up units 52, 54. The SFCC 32 has a slat control portion 32s controlling the operation of the slat driving apparatus 104s, and a flap control portion 32f controlling the operation of the flap driving apparatus 104f which is not shown in FIG. 2. In one embodiment, the MCE 48 comprises a closed-loop controller 49 for controlling speed and torque of the electric motor 36. According to another embodiment, the closed loop controller 49 is implemented as software within the control device 112, e.g. in any of the SFCCs 32-1, 32-2.

[0080] The transmission device 108 includes a left-hand torque shaft system 56a connected to the left-hand output shaft 42a and a right-hand torque shaft system 56b connected to the right-hand output shaft 42b. Each torque shaft system 56a, 56b comprises a series of the drive shafts 25, connected to each other for a common rotation. A left-hand WTB 26a acts on the last drive shaft 25 of the left-hand torque shaft system 56a near the wing tip of the left-hand wing 14a, and a right-hand WTB 26b acts on the last drive shaft 25 of the right-hand torque system 56b near the wing tip of the right-hand wing 14b. Further, a position pick-up unit 52 picks up the position (e.g. an absolute rotation angle position) of the corresponding last drive shaft 25.

[0081] The load in the transmission of each wing 14a, 14b is limited by electronic load limiter (ETL) functionality using the at least one load sensor 110. In the embodiment shown, where the mechanical power is transmitted via rotation, the torque in the transmission of each wing 14 is limited by electronic torque limiter functionality. The torque in the torque shaft systems 56a, 56b of the transmission device 108 is limited by electronic torque sensing units (TSU) 58 including a first torque sensor 60-1a, 60-1b and a second torque sensor 60-2a, 60-2b sensing the torque imposed on the corresponding output shaft 42a, 42b of the POB 24. For example, the TSUs 58 are integrated on the PCU outputs to the left-hand and right-hand wing 14a, 14b. The left-hand and right-hand first torque sensors 60-la, 60-1b are connected to the first SFCC 32-1, and the left-hand and right-hand second torque sensors 60-2a, 60-2b are connected to the second SFCC 32-2.

[0082] If the TSU 58 detects that the torque in one of the PCU output shafts 42a, 42b exceeds a predetermined over torque threshold, the electrical output signal provided by the TSU 58 triggers a monitor (implemented as computer program in the control device 112) which initiates a rapid speed reversal and torque control sequence subsequently controlling the torque to a lower level. This ensures that the prescribed loads in the transmission device 108 are not exceeded even in case of a jam. Finally, the slat driving apparatus 104s is arrested by engaging the POB 44 of the corresponding motor 36, 38.

[0083] In the default High Lift operating mode the WTBs 26a, 26b are released and the PCU 24 is providing the power to operate the high-lift system 114 with the commanded speed into any gated position.

[0084] For implementing the load sensor 110, any appropriate load sensing principle is possible. For example, the TSU 58 which replaces mechanical system torque limiters of conventional flight control surface driving apparatuses comprises appropriate mechanical and electrical components to measure the PCU output torque and to translate it into an electrical output signal (e.g. by Linear Variable Transducer (LVDT)).

[0085] In the following a health monitoring procedure for checking proper functionality of the transmission device 108 and of the load sensors 110 is described with reference to FIG. 3. The control device 112 contains a corresponding computer program and is configured to command an automatic performance of this functionality check. The functionality check leads to early detection of wear or other possible reasons for beginning deteriorations, improves long-term reliability and helps to avoid unnecessary maintenance work.

[0086] Mechanical alterations in the TSU 58 (e.g. wear or other alterations of mechanical components which transfer a torsional deflection of the output shaft 42a, 42b into a linear motion sensed by electrical sensors) will have influence on the TSU torque value readings.

[0087] An example for a TSU condition check is explained in the following with reference to FIG. 3.

[0088] FIG. 3 shows the following signals over the time t: [0089] a load sensor output signal 62 of the load sensor 110 to be tested, here for example the first torque sensor 60-1a on the left-hand output shaft 42a of the POB 24.

[0090] A brake device command signal 64 for commanding an operation of the brake device 118, here for example a WTB command signal for activating the left-hand WTB 26a.

[0091] A drive speed signal 66 of the control surface drive device 106, here for example a speed signal indicative of the rotation speed of the output of the POB 24. This speed signal can be derived, for example, from the position pick-up unit 54 at the DIFG 40.

[0092] A load command signal 68 commanding a load output from the control surface drive device 106, here preferably a MCE torque command signal outputted from an integral part of the closed-loop controller 49. [0093] a predetermined range 70 for the load sensor output signal 62 and/or the load command signal.

[0094] The functionality check of the health monitoring method comprises the following steps: [0095] a) blocking movement of the transmission device 108 by means of the brake device 118, [0096] b) commanding the control surface drive device 106 to apply a load on the blocked transmission device, and [0097] c) determining whether at least one load sensor output signal 62 of the at least one load sensor 110 is within the predetermined range 70.

[0098] Referring to FIG. 3, the WTB engages at time t1. Further, the control surface drive devise 106 receives a command to drive with low speed. After t1, the drive speed signal 66 starts to drop. The closed-loop controller 49 responds by sending a load command signal 68 (MCE torque signal) which rises linearly. Further, since the transmission device 108 is blocked, the load sensor 110 outputs the load sensor output signal 62 which rises linearly. The control device 112 determines whether the load sensor output signal 62 remains in the predetermined range 70. Further, the control device 112 determines whether the load command signal 68 remains in the predetermined range 70. If any of the signals 62, 68 leaves the predetermined range, a failure message is issued. Otherwise, the test is continued until the load sensor output signal reaches the predetermined ETL over torque threshold 72 as mentioned above. According to another embodiment (not shown), the test ends when the load command signal 68 reaches a predetermined load limit, for example a threshold which corresponds to the ETL over torque threshold 72.

[0099] FIG. 3 shows for example a TSU integrity check as part of a WTB and/or POB performance test. A preferred embodiment is described in the following in more detail.

[0100] As part of the WTB/POB performance test, which is carried out regularly, the following sequence can be used to check the correct function of the TSU 58. The SFCC 32-1, 32-2 commands the electric drive of the PCU 24 with low speed against the engaged WTB 26a, 26b causing stall of the electric drive. The speed control of the PCU electric drive implemented in the SFCC 32-1, 32-2 is established by a closed speed control loop with an integral part. The output of this speed loop is the MCE torque command signal 68 which correspond to a commanded motor torque. Because of the integral part of the controller 49, the MCE torque command signal 68 steadily increases during the stall condition. As a consequence, with increasing electric motor torque, the torque at the PCU 24 output which is measured by the TSU 58 also increases. The TSU Torque readingload sensor output signal 62is compared by the SFCC 32-1, 32-2 to a reference torque value (e.g. MCE torque command signal 68 from the speed loop). When the deviation of these two signals 62, 68 exceeds a defined threshold, the test is aborted and failed. As long as during motor stall both signals following within an acceptable range the motor drive command remains active until a defined threshold 72 is achieved. The test is successfully passed when a defined threshold is achieved (e.g. the ETL trip threshold). The correct function of the TSU 58 is proven when the TSU Torque reading is following the rise of the commanded motor torque signal within an acceptable range until the abort condition is achieved.

[0101] In case that the speed loop is implemented in the MCE 48 the corresponding evaluation will be performed in the MCE 48 and the results are sent to the SFCC 32-1, 32-2.

[0102] In order to reduce maintenance work and to improve long-time reliability, a health monitoring method has been described for checking a functionality of a flight control surface driving apparatus 104 using at least one load sensor 110 for sensing a load imposed on a control surface drive device 106, the method comprising at least one of the steps: [0103] a) blocking movement of the transmission device 108 by means of a brake device 118, [0104] b) commanding the control surface drive device 106 to apply a load on the blocked transmission device, and [0105] c) determining whether at least one load sensor output signal 62 of the at least one load sensor 110 is within a predetermined range.
Further, a flight control surface drive apparatus 104, a flight control system 100 and an aircraft 10 comprising a control device 112 configured to automatic command conduct of such health monitoring method have been described.

[0106] While the health monitoring has been described in connection with driving flight control surfaces which can be primary and secondary flight control surfaces, the health monitoring could also be applied to other movable surfaces of an aircraft such as cargo doors, landing gear doors, etc.

[0107] The systems and devices described herein may include a controller or a computing device comprising a processing and a memory which has stored therein computer-executable instructions for implementing the processes described herein. The processing unit may comprise any suitable devices configured to cause a series of steps to be performed so as to implement the method such that instructions, when executed by the computing device or other programmable apparatus, may cause the functions/acts/steps specified in the methods described herein to be executed. The processing unit may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

[0108] The memory may be any suitable known or other machine-readable storage medium. The memory may comprise non-transitory computer readable storage medium such as, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory may include a suitable combination of any type of computer memory that is located either internally or externally to the device such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. The memory may comprise any storage means (e.g., devices) suitable for retrievably storing the computer-executable instructions executable by processing unit.

[0109] The methods and systems described herein may be implemented in a high-level procedural or object-oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of the controller or computing device. Alternatively, the methods and systems described herein may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems described herein may be stored on the storage media or the device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein.

[0110] Computer-executable instructions may be in many forms, including modules, executed by one or more computers or other devices. Generally, modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically, the functionality of the modules may be combined or distributed as desired in various embodiments.

[0111] It will be appreciated that the systems and devices and components thereof may utilize communication through any of various network protocols such as TCP/IP, Ethernet, FTP, HTTP and the like, and/or through various wireless communication technologies such as GSM, CDMA, Wi-Fi, and WiMAX, is and the various computing devices described herein may be configured to communicate using any of these network protocols or technologies.

[0112] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

REFERENCE SIGNS LIST

[0113] 10 aircraft [0114] 12 fuselage [0115] 14a left-hand wing [0116] 14b right-hand wing [0117] 16 engine [0118] 18 high-lift device [0119] 20 slat [0120] 20.1a-20.7a left-hand slats [0121] 20.1b-20.7b right-hand slats [0122] 22 flap [0123] 24 PCU [0124] 25 drive shaft [0125] 26a left-hand WTB [0126] 26b right-hand WTB [0127] 32-1 first SFCC [0128] 32-2 second SFCC [0129] 32s slat control portion [0130] 32f flap control portion [0131] 34 input device [0132] 36 electric motor [0133] 38 hydraulic motor [0134] 40 DIFG [0135] 42a left-hand output shaft [0136] 42b right-hand output shaft [0137] 44 POB [0138] 46 hydraulic valve block [0139] 48 MCE [0140] 49 closed-loop controller [0141] 50-1 electric busbar [0142] 50-2 electric busbar [0143] 52 position pick-up unit (output of transmission device) [0144] 54 position pick-up unit (DIFG) [0145] 56a left-hand torque shaft system [0146] 56b right-hand torque shaft system [0147] 58 TSU [0148] 60-1a left-hand first torque sensor (example for first load sensor) [0149] 60-1b left-hand first torque sensor (example for first load sensor) [0150] 60-2a left-hand second torque sensor (example for second load sensor) [0151] 60-2b left-hand second torque sensor (example for second load sensor) [0152] 62 load sensor output signal [0153] 64 brake device command signal [0154] 66 drive speed signal (actual drive speed) [0155] 68 load command signal [0156] 70 predetermined range [0157] 72 over torque threshold [0158] 100 flight control system [0159] 102 control surface [0160] 104 flight control surface driving apparatus [0161] 104s slat driving apparatus [0162] 104f flap driving apparatus [0163] 106 control surface drive device [0164] 108 transmission device [0165] 110 load sensor [0166] 112 control device [0167] 114 high-lift system [0168] 118 brake device [0169] L load, for example torque [Nm] [0170] t time [0171] t1 engagement of WTB starts