Automatic detection of hardware configuration of onboard devices in aircraft

Abstract

The present invention relates to a method for detecting the hardware configuration of an onboard device in an aircraft, the device being capable of receiving a setpoint current (Ic) as input and generating a response current (I) as output, the method comprising the following steps: a) sending a setpoint current (Ic) to the input of the device at a given time (t0); b) measuring one or more values ​​of the response current (I) at the output of the device during a measurement time interval defined between two instants (t1 and t2) after the initial instant (t0); c) inferring the hardware configuration of the device from the measured value or values ​​of the response current (I).

Description

Technical Field

[0001] The present invention relates to an onboard device in an aircraft, more specifically a fuel conditioning device, in particular for a turbomachine, such as a turbojet engine or a turboprop engine. Background Art

[0002] Aircraft have several onboard computers designed to monitor the various onboard devices to ensure their proper operation. Specifically, any device whose malfunction would be critical requires monitoring by two computers, one of which is dedicated for redundancy and is used in the event of a malfunction of the other. These two computers typically form two channels of a control unit known as an Electronic and Protection Monitoring Unit (EPMU).

[0003] These computers are also called protection computers. One of their tasks is to prevent the flow of fuel to the turbine if a malfunction is detected, in order to avoid catastrophic events.

[0004] From one turbine model to another, depending on its architecture, a protection calculator may be required to control the fuel metering and regulating devices (fuel metering unit, FMU). For example, if a turbine overspeed is detected, the EPMU sends a command to the FMU to control and / or reduce fuel injection.

[0005] There are different models of regulating devices which have different hardware characteristics and therefore require, specifically, different control currents.

[0006] During maintenance operations, it is also possible to replace the first FMU model with a second FMU model.Sending too high a control current may damage the device, and sending too low a control current may affect the protection of the turbine in the event of a malfunction.

[0007] Currently, information about the turbine architecture, ie number, location and FMU model used, is input into the protection application software run by the protection calculator.

[0008] Therefore, during maintenance operations, modifications to the FMU model require modifications to the protection application software to avoid any operational problems.

[0009] The object of the present invention is precisely to provide a simple, effective and economical solution to the problems of the prior art described above. Summary of the Invention

[0010] For this purpose, a method is proposed for detecting the hardware configuration of an onboard device in an aircraft, said device being capable of receiving a setpoint current Ic as input and of generating a response current I as output, said method comprising the following steps:

[0011] a) sending a setpoint current Ic to the input of the device at a given time t0;

[0012] b) one or more values ​​of the response current I at the output of the measuring device in a measuring time interval defined between two instants t1 and t2 after the initial instant t0;

[0013] c) Inferring the hardware configuration of the device from one or more values ​​of the measured response current I.

[0014] Inferences about the hardware configuration of the device may be drawn from one or more values ​​of the measured current I and the current response characteristics of the device.

[0015] When the device is, for example, an FMU, such a method implemented on the protection computer makes it possible to automatically detect the FMU models connected to the protection computer during the phase of powering up the device, ie at start-up of said device, and therefore to adapt the control currents to each FMU model.

[0016] Therefore, based on the electrical characteristics of the FMU model, it is possible to infer its model. To this end, the current response to the control current is analyzed to automatically (i.e., without human intervention) infer the hardware configuration of each device. The term "analysis" refers to analyzing the value of the device's output current in response to the control current and its temporal variation.

[0017] Thus, by performing a diagnostic test of the configuration, the solution ensures the control of devices with heterogeneous hardware configurations while guaranteeing functionality against unexpected malfunctions of the turbine (dangerous engine effects).

[0018] The invention is applicable to any device comprising an electric actuator comprising a coil and therefore having an inductance. For example, in the case of an FMU, the invention is applicable thanks to the presence of an electrohydraulic servo valve (EHSV) allowing the control of a fuel metering valve (FMV).

[0019] In addition, the hardware configuration of the device may be at least one of the following configurations:

[0020] - a first device having a first inductance L1;

[0021] - a second device having a second inductance L2;

[0022] - a device with unknown hardware configuration, and where L2 = x·L1, where And x≥10.

[0023] Therefore, a device having an L1 first inductance between 50 mH and 150 mH is considered a low inductance device. A device having an L2 second inductance between 0.9 H and 1.5 H is considered a high inductance device.

[0024] Step c) may consist of comparing one or more values ​​of the measured response current with a first threshold value I min1,FMU1 At and at a second threshold value I lower than the first threshold value max2,FMU2 The first threshold I measured at is compared so that:

[0025] If the value of the measured current I is higher than the first threshold value I min1,FMU1 , then the first device is detected,

[0026] If the value of the measured current I is lower than the second threshold value I max2,FMU2 , then the second device is detected,

[0027] If the value of the measured current I is between the second threshold and the first threshold, a device with an unknown hardware configuration is detected.

[0028] Thus, by acquiring the current, the method compares the value of the measured current with the minimum value of the output current of the first device and with the maximum value of the output current of the second device at the same instant t in response to the same control current.

[0029] Additionally, the method may further comprise the following steps:

[0030] - measuring one or more values ​​of the response current I at at least one time t3 after the upper limit value t2 of the measurement time interval, and

[0031] - If the value of the measured response current I is lower than the third threshold value (I min3 ), it is inferred that the hardware configuration is the hardware configuration of the first defective device or the hardware configuration of the second defective device.

[0032] Therefore, the third threshold value allows for further identification of the first faulty device or the second faulty device.

[0033] The hardware configurations of the first device and the second device may have the same resistance value.

[0034] Preferably, the first inductor t1 may be approximately 100 mH and the second inductor L2 may be approximately 1 H.

[0035] In addition, the response current of the device can be expressed as:

[0036]

[0037] Where L is the impedance of the device and R is the resistance of the device.

[0038] Depending on the value of the current measured at the output of the device, and knowing the resistance of the device, independently of its structure, it is possible to automatically determine the hardware configuration of the device.

[0039] In other words, the response time of the devices to the control currents sent by the calculator allows the calculator to automatically identify the hardware configuration of each device when it starts up. The protection calculator can then adapt the levels of these control currents to each device according to its hardware configuration (i.e., its model).

[0040] Alternatively, the setpoint current may be sent by an onboard protection computer of the aircraft.The setpoint current Ic may be approximately 400 mA.

[0041] Based on the values ​​I1, I2 of the current measured at times t1 and t2, it is possible to characterize the response of the device to the control current, more precisely its response time. The measurement of the current values ​​at two points in time t1 and t2 ensures that the method has a certain robustness with respect to environmental variability that can affect the time of the device.

[0042] Specifically, steps a) to c) can be performed when the device is switched on.

[0043] Furthermore, the device may include an actuator for the moving part of the fuel metering unit, the actuator comprising at least one stationary electrical coil and a moving core. In practice, there are at least two types of fuel metering units with different material configurations, characterized by either low or high impedance, as detailed above. This is because the electrohydraulic servo valves (EHSVs) used to control the fuel metering valves (FMVs) used in the two FMU models have different impedances. Thanks to the present invention, during maintenance work, a fuel metering unit of the first type can be replaced by a fuel metering unit of the second type without the risk of receiving an inappropriate level of control current. The current level transmitted by the protection computer is then automatically adapted.

[0044] This document also relates to a computer program comprising instructions for implementing the method as described above when executed on a processor.

[0045] The present document also relates to a protected computer comprising a processor coupled to a memory such that the aforementioned program is stored on the memory. Furthermore, the present document relates to a protected computer comprising a processor coupled to a memory having stored thereon instructions for implementing the method as described above when executed on the computer. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] [ Figure 1] shows the time evolution of the maximum output current and the minimum output current of the first fuel metering unit model and the second fuel metering unit model in response to a control current of approximately 400 mA;

[0047] [ Figure 2 ] is a flow chart of a method for detecting a hardware configuration of an onboard device in an aircraft according to a first embodiment;

[0048] [ Figure 3 ] shows measurements performed in the method according to the first embodiment;

[0049] [ Figure 4A ] is a graph showing the maximum output current and the minimum output current of the fuel metering unit of the first model in response to the set point current;

[0050] [ Figure 4B ] is a curve representing the output current of the first model when a short circuit occurs on one of the channels of the control unit;

[0051] [ Figure 5A ] is a graph showing the maximum output current and the minimum output current of the fuel metering unit of the first model in response to the set point current;

[0052] [ Figure 5B ] is a curve representing the output current of the first model when a short circuit occurs on one of the channels of the control unit; DETAILED DESCRIPTION

[0053] During maintenance operations, replacement of a fuel metering unit (FMU) does not necessarily imply an identical replacement, such that an FMU having a first hardware configuration may be replaced by an FMU having a second hardware configuration different from the first hardware configuration.

[0054] Two models of metering units are used today, each with its own unique hardware configuration.

[0055] The first model, called FMUcutback, has a first inductance L1 of approximately 100 mH. Generally, the first inductance of this first model is between 0 mH and 150 mH.

[0056] The second model, referred to as FMU Baseline, has a second inductance L2 of approximately 1 H. Generally, the second inductance of this second model is between 0.9 H and 1.5 H.

[0057] Both material configurations have the same resistance. However, the resistance of these FMUs depends largely on the temperature to which the FMU is exposed. Therefore, the resistance of this device exhibits high variability, depending on the resistance tolerance and the temperature of the environment in which the FMU is integrated.

[0058] Therefore, in general, the first inductor L1 and the second inductor L2 are respectively referred to as low inductance and high inductance, and these inductances can be expressed as L2 = x·L1, where And x≥10.

[0059] Figure 1 The current responses of the first FMU1 model and the second FMU2 model to a setpoint current 2 of approximately 400 mA are illustrated.

[0060] The current response of the first FMU1 model to this setpoint current lies between the curve for maximum output current 4 and the curve for minimum output current 6. This variation in output current depends on the temperature to which the fuel metering unit is subjected.

[0061] The current response of the first FMU 2 model to this setpoint current lies between the curves for the maximum output current 8 and the curves for the minimum output current 10 .

[0062] Generally speaking, the output current of the device is expressed as:

[0063]

[0064] Where L is the impedance of the device and R is the resistance of the device, which may vary depending on the temperature to which the FMU is subjected.

[0065] Thus, two zones Z1 and Z2 are delimited, the first zone Z1 representing all the values ​​that can be taken by the output current of the first model FMU1 and the second zone Z2 representing all the values ​​that can be taken by the output current of the second model FMU2. Figure 1 As can be seen in , these zones Z1 , Z2 do not overlap. The detection method according to the invention relies on this last point to allow automatic detection of the FMU model used.

[0066] Figure 2 An embodiment of a method for detecting the hardware configuration of an onboard device in an aircraft, in this case a fuel metering unit, is described.

[0067] As reference Figure 1 In detail, the two fuel metering unit models FMU1 and FMU2 are adapted to receive a setpoint current Ic as input and, in response to this setpoint current, generate an output current I.

[0068] The metering unit is embedded in an environment where it is supervised by a dual-channel control unit (EPMU) (i.e., two calculators with redundancy for protection). These two calculators, for example consisting of two electronic cards housed in the same housing, are connected to the same FMU. This ensures that if one unit malfunctions, the remaining healthy calculator maintains control of the fuel metering unit. The first step A of the method consists of sending a setpoint current Ic to the device input at a given time t0.

[0069] As from Figure 3 As can be seen from the example in, the set point current Ic is the DC current emitted from t0=0ms.

[0070] A second step B of the method measures the values ​​of the currents I1 and I2 at the output of the device at times t1 and t2 after t0 .

[0071] During this second step, for example, two measurements of the current response at the output of the current device are made ( Figure 3 ) is performed at two times t1 and t2 after t0.

[0072] The times t1 and t2 are selected to be approximately 5 ms, for example, in order to define a measuring time interval of, for example, less than 1 ms. Figure 1 Schematically illustrated in .

[0073] As shown in the simplified diagram, depending on the current value measured in the measuring time interval between t1 and t2 , the hardware configuration of the fuel metering unit can be inferred in a third step C.

[0074] For example, by measuring the response current I1 at time t1 and the response current I2 at time t2, the inference is based on comparing the values ​​I1, I2 with the following range:

[0075] -Comparison of I1 at time t1 and I2 at time t2:

[0076] -If I1∈[I min 1；FMU1 ;I max 1；FMU1 ] and I2∈[I min 2；FMU1 ;I max 2；FMU1 ], i.e., in the area Z1, the fuel metering unit has the hardware configuration of the first model FMU1;

[0077] -If I1∈[I min 1；FMU2 ;I max 1；FMU2 ] and I2∈[I min 2；FMU2;I max 2；FMU2 ], that is, in zone Z2, the fuel metering unit has the material configuration of the second model FMU2.

[0078] In other words, this comparison allows the response time of the fuel metering unit to be characterized and compared with the known response times of the first and second models.

[0079] As can be seen, if I1∈[I max 1；FMU2 ;I min 1；FMU1 ] and I2∈[I max 2；FMU2 ;I min 2；FMU1 ], i.e. in zone Z3, it is not possible to determine the material configuration of the fuel metering unit. When the method is implemented on the ECU, an error message is returned.

[0080] Of course, it is possible to limit the method to the measurement of a single value of the output current at time t within the measurement time interval between t1 and t2 and to infer the hardware configuration of the device depending on the value of the measured current I. In other words, in order to identify the position at which the measured current is located in zone Z1 or Z2, I is located.

[0081] For example, if a short circuit occurs in one of the EPMU channels, the third measurement at time t3 may be useful. Figure 3 This time t3 identified in is later than time t2. Figure 3 This time identified in is later than the time of the detected current and allows the identification of a current in zone Z4 below the output current of zone Z2, which then corresponds to the first device or the second device having a material fault. In this case, Figure 4B and 5B As can be seen from FIG, the output current of the fuel metering unit is affected in response to the control current of about 400 mA. By comparing the output current value at time t3 with the third threshold value I min3 By making this comparison, it is possible to detect a faulty device.

[0082] An example of a device fault is actuator drift, where the response time of the actuator is outside a predefined range when subjected to a current load. Another example of a fault may be a short circuit of one coil of a dual coil actuator.

[0083] However, as in the case described above, the evolution of the output current of the fuel metering unit remains similar to the case without a short circuit.

[0084] In fact, if Figure 4AAs can be seen from FIG1 , assuming that the setpoint current is emitted from t=0 ms, in response to a setpoint current of, for example, 400 mA, the output current of the first model FMU1 reaches 400 mA between 1.5 ms and 2 ms (depending on the temperature of the fuel metering unit environment). In the event of a short circuit, the value of 400 mA is reached at 2 ms, as shown in FIG1 . Figure 4B Thus, despite a short circuit in one of the channels of the control unit, the test output current value remains differentiated.

[0085] This is also confirmed for the second hardware configuration. Figure 5A As can be seen from FIG, considering that the set current of 400 mA is emitted from t0=0 ms, the output current of the second model FMU2 reaches 300 mA between 50 ms and 120 ms (depending on the temperature of the fuel metering unit environment). In the case of a short circuit, the value of 300 mA is reached at about 30 ms, as shown in FIG. Figure 5B Thus, the response time is about 15 times longer than that of the first configuration, as in the absence of a short circuit.

[0086] Therefore, regardless of whether there is a short circuit, the current measurement at two times of about 2 ms, for example, at times t1 and t2 between 0 ms and 2 ms, can be used to infer the hardware configuration of the fuel metering unit. In fact, if the measured value I1 is within the range corresponding to the Z3 area, the value of the hardware configuration cannot be inferred, but I2 is within [I min 2；FMU1 ;I max 2；FMU1 ] or [I min 2；FMU2 ;I max 2；FMU2 ], it can still be inferred that the fuel metering unit has the same hardware configuration as the first model FMU1 or the second model FMU2.

[0087] Preferably, the method is performed by the control unit when the device is switched on. Specifically, the method is performed by each of the protection computers of the control unit.

[0088] For this purpose, a protection computer comprising a processor coupled to a memory contains in the memory a computer program comprising instructions for implementing the method as described above when executed on the processor.

Claims

1. A method for detecting a hardware configuration of an onboard device in an aircraft, the device being capable of receiving a setpoint current (Ic) as input and generating a response current (I) as output, the method comprising the following steps: a) sending a setpoint current (Ic) to the input of the device at a given initial moment (t0); b) measuring one or more response current values ​​at the output of the device during a measurement time interval defined between two instants (t1, t2) after the initial instant (t0); c) inferring said hardware configuration of said device based on one or more said values ​​of said measured response current (I) and a current response characteristic of said device.

2. The method according to claim 1, characterized in that The hardware configuration of the device is at least one of the following configurations: - a first device having a first inductance (L1); - a second device having a second inductance (L2); - a device with unknown hardware configuration, and where L2 = x·L1, where And x≥10.

3. The method according to claim 2, characterized in that Step c) comprises comparing the min1,FMU1 ) and at a second threshold value (I max2,FMU2 ) is measured at one or more values ​​of the response current (I) such that: - If the value of the measured response current (I) is higher than the first threshold value (I min1,FMU1 ), the first device is detected, - If the value of the measured response current (I) is lower than the second threshold value (I max2,FMU2 ), then the second device is detected, If the value of the measured current (I sare) is between the second threshold and the first threshold, a device with an unknown hardware configuration is detected.

4. The method according to claim 1 or 2, further comprising the steps of: - measuring one or more values ​​of said response current (I) at at least one time (t3) after an upper limit value of said measurement time interval, and - If said value of the measured response current (I) is lower than a third threshold value (I min3 ), it is inferred that the hardware configuration is the hardware configuration of the first defective device or the hardware configuration of the second defective device.

5. The method according to claim 2, characterized in that The hardware configurations of the first device and the second device have the same resistance value.

6. The method according to claim 2, characterized in that The first inductor (L1) is 100mH and the second inductor (L2) is 1H.

7. The method according to claim 1, characterized in that The response current (I) at the output of the device is expressed as: Where L is the impedance of the device, R is the resistance of the device, and Ic is the set point current.

8. The method according to claim 1, characterized in that The setpoint current (Ic) is sent by a protection computer on board the aircraft.

9. The method according to claim 1, characterized in that Steps a) to c) are performed when the device is powered on.

10. A protected computer comprising a processor coupled to a memory on which are stored instructions for carrying out the method according to any one of claims 1 to 8 when executed on the computer.

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