Main flight control system for aircraft and its control method

Abstract

Disclosed are a main flight control system for an aircraft and its control method. The main flight control system may include a control unit and a main flight control computer. The control unit may receive a first slat position signal generated by a first position sensor on the slat from a high-lift system, and may receive a second slat position signal from a second position sensor mounted on the slat. When the main flight control computer is operating normally, the main flight control computer may generate a control command based on an operation input signal from a control device and the first slat position signal, and the control unit generates a control surface command based on the control command to control one or more control surfaces of the aircraft. When a failure occurs in the main flight control computer, the control unit may generate a control surface command based on the operation input signal and the second slat position signal to control one or more control surfaces of the aircraft.

Description

Technical Field

[0001] The present invention relates to an aircraft, and particularly to a main flight control system for an aircraft and a control method thereof. Background Art

[0002] The high-lift system of an aircraft includes a slat located at the leading edge of the wing and a flap located at the trailing edge of the wing. During low-speed phases such as takeoff and landing of the aircraft, the slat at the leading edge and the flap at the trailing edge extend outwards and bend downwards to increase the wing area and change the configuration, thereby providing lift for the aircraft to obtain sufficient takeoff speed.

[0003] When a pilot operates a flap / slat control lever (FSCL), the flap / slat electronic control unit (FSECU) of the high-lift system detects a valid lever command signal and then issues a command to a power drive unit (PDU) to drive the flap and / or slat to move. A position sensor located on the flap and / or slat can feedback the position of the wing surface to the FSECU.

[0004] The slat position signal can be used to represent two states: the slat is open and the slat is retracted. The control law of the main flight control system will calculate the rudder control command of the aircraft in different configurations based on these two states. The slat position information required by the main flight control system generally comes from the slat position signal issued by a high-lift computer. For current commercial aircraft, there are two layouts for the high-lift system and the main flight control system: 1. The control of the high-lift system is integrated in the main flight control computer of the main flight control system; 2. The high-lift system uses an independent control device (for example, a high-lift computer, which may include an FSECU). In the second layout, the control law of the main flight control system requires the slat position signal provided by the high-lift computer for parameter adjustment to generate a rudder control command.

[0005] However, the slat position signal provided by the high-lift computer may be incorrect (for example, due to a common mode failure). In the case where the main flight control system cannot perform signal fault detection, the rudder control command generated based on the incorrect slat position signal may cause the rudder to deflect non-instructively, affecting the safety of the aircraft.

[0006] Therefore, there is a need in the art for an improved main flight control system for an aircraft and a control method thereof. Summary of the Invention

[0007] The present invention provides a main flight control system for an aircraft and its control method. According to an embodiment of the present invention, the main flight control system can use a detection device independent of the high-lift system to provide a slat position signal, and further can perform fault monitoring based on a redundancy management algorithm for integrity analysis. When the main flight control computer is operating normally, the main flight control system uses the slat position signal sent by the high-lift computer for control surface control. At this time, the main flight control computer can also perform fault monitoring to detect slat signal faults in a timely manner; when the main flight control computer fails, the main flight control system enters a direct control mode and uses an independent slat position sensor to provide a slat signal for control surface control. According to an embodiment of the present invention, the failure probability of the independent sensor itself can be less than 1e-5 / FH, there is no single-point failure, and it is independent of the slat position signal sent by the high-lift calculation, meeting the safety requirements.

[0008] In an embodiment of the present invention, there is provided a main flight control system for an aircraft, which includes: a control unit, the control unit is connected to the high-lift system to receive a first slat position signal from the high-lift system, and the first slat position signal is generated based on the slat position detected by a first position sensor installed on the slat associated with the high-lift system; a second position sensor installed on the slat, which is configured to generate a second slat position signal based on the detected slat position, wherein the control unit also receives the second slat position signal; and a main flight control computer connected to the control unit, wherein when the main flight control computer is operating normally, the main flight control computer generates a control command based on an operation input signal from a control device and the first slat position signal, and the control unit generates a control surface command based on the control command to control one or more control surfaces of the aircraft, and wherein when the main flight control computer fails, the control unit generates a control surface command based on the operation input signal and the second slat position signal to control the one or more control surfaces of the aircraft.

[0009] In one aspect, when the main flight control computer is operating normally, the main flight control computer determines whether the second position sensor has a fault based on a comparison between the first slat position signal and the second slat position signal.

[0010] In one aspect, the control unit generates a first flap status signal based on the first flap position signal and a second flap status signal based on the second flap position signal, where the first flap status signal and the second flap status signal each indicate whether the flap is in an open state or a retracted state. The primary flight control computer determines, during normal operation, whether the first flap status signal and the second flap status signal indicate the same state. If the first flap status signal and the second flap status signal indicate different states for a threshold time period or more, the primary flight control computer determines that the second position sensor is faulty. Alternatively, the primary flight control computer determines, during normal operation, a first state transition time at which the first flap status signal changes state and a second state transition time at which the second flap status signal changes state. If the difference between the first state transition time and the second state transition time exceeds a threshold, the primary flight control computer determines that the second position sensor is faulty.

[0011] In one aspect, during normal operation, the primary flight control computer determines whether the first flap position signal is faulty by comparing a plurality of first flap position signals received by the control unit from multiple channels of the high-lift system. If the first flap position signal is faulty, the primary flight control computer generates a control command based on the previous last valid first flap position signal to control one or more control surfaces of the aircraft.

[0012] In one aspect, the control unit generating a control surface command based on the operation input signal and the second flap position signal includes: the control unit generating a second flap status signal based on the second flap position signal, the second flap status signal indicating whether the flap is in an open state or a retracted state, and the control unit generating a control surface command based on the operation input signal from the control device and a gain corresponding to the second flap status signal.

[0013] In one aspect, the one or more control surfaces include one or more of the following: elevator, horizontal stabilizer, rudder, spoiler, aileron.

[0014] In one aspect, the first position sensor and the second position sensor each include one or more of the following: rotary differential position sensor, linear displacement sensor, cable type position sensor, optical encoder sensor.

[0015] In one embodiment of the present invention, an aircraft is provided, which includes: a high-lift system; and a primary flight control system as described in any one of the above.

[0016] In one embodiment of the present invention, a control method for a main flight control system of an aircraft is provided, which includes: receiving a first slat position signal from a high-lift system, the first slat position signal being generated based on the slat position detected by a first position sensor mounted on the slat associated with the high-lift system; receiving a second slat position signal detected by a second position sensor mounted on the slat; when the main flight control computer is operating normally, the main flight control computer generates a control command based on an operation input signal from a control device and the first slat position signal, and a control surface command is generated by a control unit based on the control command to control one or more control surfaces of the aircraft; and when the main flight control computer fails, the control unit generates a control surface command based on the operation input signal and the second slat position signal to control the one or more control surfaces of the aircraft.

[0017] In one aspect, when the main flight control computer is operating normally, the main flight control computer determines whether the second position sensor is faulty based on a comparison of the first slat position signal and the second slat position signal.

[0018] In one aspect, the control method further includes: generating a first slat state signal based on the first slat position signal and generating a second slat state signal based on the second slat position signal, wherein the first slat state signal and the second slat state signal each indicate that the slat is in an open state or a retracted state, determining whether the first slat state signal and the second slat state signal indicate the same state, if the first slat state signal and the second slat state signal indicate different states for more than a threshold time period, then determining that the second position sensor is faulty, or determining a first state switching time when the first slat state signal changes state, and a second state switching time when the second slat state signal changes the state, if the difference between the first state switching time and the second state switching time exceeds a threshold, then determining that the second position sensor is faulty.

[0019] In one aspect, when operating normally, the main flight control computer determines whether the first slat position signal is faulty by comparing multiple first slat position signals received from multiple channels of the high-lift system. If the first slat position signal is faulty, the main flight control computer generates a control command based on the previous last valid first slat position signal to control the one or more control surfaces of the aircraft.

[0020] In one aspect, the control unit generating a control surface command based on the operation input signal and the second slat position signal includes: the control unit generating a second slat state signal based on the second slat position signal, the second slat state signal indicating that the slat is in an open state or a retracted state, and the control unit generating a control surface command based on the operation input signal from the control device and a gain corresponding to the second slat state signal.

[0021] In one aspect, the one or more control surfaces include one or more of the following: elevator surface, horizontal stabilizer surface, rudder, spoiler, aileron.

[0022] In one aspect, each of the first position sensor and the second position sensor includes one or more of the following: rotary differential position sensor, linear displacement sensor, cable type position sensor, optical encoder sensor. Description of the Drawings

[0023] Figure 1 A schematic diagram showing the normal mode slat signal flow according to one embodiment is shown.

[0024] Figure 2 A schematic diagram showing the direct control mode slat signal flow according to one embodiment is shown.

[0025] Figure 3 A schematic block diagram of a primary flight control system according to one embodiment of the present invention is shown.

[0026] Figure 4 A schematic block diagram of a primary flight control system according to another embodiment of the present invention is shown.

[0027] Figure 5 A schematic installation diagram of the slat position sensor of the primary flight control system according to one embodiment of the present invention is shown.

[0028] Figure 6 A schematic diagram showing the generation of a slat state signal according to one embodiment of the present invention is shown.

[0029] Figure 7 A schematic diagram showing the slat position signal fault monitoring logic according to one embodiment of the present invention is shown.

[0030] Figure 8 A flowchart of a control method for a primary flight control system according to one embodiment of the present invention is shown. Detailed Description of the Invention

[0031] The present invention will be further described below in conjunction with specific embodiments and drawings, but the protection scope of the present invention should not be limited thereby.

[0032] Disclosed are a main flight control system for an aircraft and its control method. In an embodiment of the present invention, the main flight control system may include a control unit and a main flight control computer. The control unit may receive a first slat position signal generated by a first position sensor on the slat from the high-lift system, and may receive a second slat position signal from a second position sensor mounted on the slat. When the main flight control computer is operating normally, the main flight control computer may generate a control command based on an operation input signal from a control device and the first slat position signal, and the control unit generates a control surface command based on the control command to control one or more control surfaces of the aircraft. When a failure occurs in the main flight control computer, the control unit may generate a control surface command based on the operation input signal and the second slat position signal to control one or more control surfaces of the aircraft.

[0033] Figure 1 A schematic diagram showing the slat signal flow in normal mode according to an embodiment is shown.

[0034] The high-lift system may include a high-lift computer 130, a position sensor 132, a flap / slat control lever (FSCL, not shown), a power drive unit 133, etc. The high-lift computer 130 may receive a handle command signal from the flap / slat control lever (FSCL), and then issue a command to the power drive unit 133 to drive the flap and / or slat to move. One or more position sensors 132 may be located on the slat to detect the slat position and feedback the slat position to the high-lift computer 130. The high-lift computer 130 may also provide slat position signals of one or more channels to the control unit 120 of the main flight control system. By way of example and not limitation, the slat position signal may indicate the position (or angle) where the slat is located.

[0035] The main flight control system may include a main flight control computer 110 and a control unit 120. The control unit 120 may transmit the slat position signal received from the high-lift system (e.g., the high-lift computer 130) to the main flight control computer 110. The main flight control computer 110 may perform control law calculations and generate a control command based on an operation input signal from a control device (e.g., a joystick, a steering wheel, and pedals, etc.) and the slat position signal. The control command may be provided to the control unit 120, and the control unit 120 generates a control surface command based on the control command to control the movement of the control surfaces of the aircraft. By way of example and not limitation, the control surfaces of the aircraft may include elevator surfaces, horizontal stabilizer surfaces, rudders, spoilers, ailerons, etc.

[0036] The high-lift computer 130 can detect signal faults in the flap position feedback by the position sensor 132 through internal redundant monitoring channels. For example, it can compare and monitor the flap positions detected by monitoring channel 1 and monitoring channel 2 to ensure the integrity of the flap position signal. At the same time, the primary flight control computer 110 can also perform fault monitoring in the normal state. For example, the primary flight control computer 110 can receive multi-channel flap position data from the high-lift computer 130 and identify faults through comparison and other means. Thus, even if the high-lift computer 130 fails and fails to detect the fault and issues an incorrect flap position signal, the primary flight control computer 110 can still detect the fault in the flap position signal and perform control law reconstruction, thereby generating the correct control command, enabling the control unit 120 to correctly generate the flap command and having no impact on the safety of the aircraft.

[0037] Figure 2 FIG. shows a schematic diagram of the flap signal flow in the direct control mode according to an embodiment. Referring to Figure 1 , once the primary flight control computer 110 loses its working ability, the primary flight control system enters the direct control mode, that is, the control unit 120 directly generates the flap command based on the flap position signal received from the high-lift system (for example, the high-lift computer 130). In this case, the fault monitoring function of the primary flight control computer 110 will be lost. At this time, if the flap position signal sent by the high-lift computer 130 is incorrect (for example, due to a common mode fault), the primary flight control system will lose the fault monitoring of this signal, and the incorrect flap position signal may cause the flap to deflect non-instructively, resulting in an aircraft safety accident.

[0038] Therefore, this solution poses high requirements for the design of the high-lift computer to prevent common mode faults. Even redundant non-similar designs need to be adopted in the monitoring channels (if similar designs are adopted in the monitoring channels, the probability of incorrect flap position signals caused by common mode may not meet the disaster-level fault probability requirement of 1e-9 / FH), which will bring huge cost pressure and technical difficulties to the OEM.

[0039] Figure 3 FIG. shows a schematic block diagram of the primary flight control system according to an embodiment of the present invention. Figure 3 The flap signal flow when the primary flight control computer is working properly is also shown in

[0040] The high-lift system may include a high-lift computer 330, one or more first position sensors 332, a flap / slat control lever (FSCL, not shown), a power drive unit (not shown), etc. The high-lift computer 330 may receive a handle command signal from the flap / slat control lever (FSCL), and then issue commands to the power drive unit to drive the movement of the flaps and / or slats. The first position sensor 332 may be located on the slat to detect the slat position and feed back the slat position to the high-lift computer 330. For example, each slat on each side may include a plurality of individual airfoils, and each airfoil or some of the airfoils may be provided with an associated first position sensor 332. The high-lift computer 330 may perform signal fault detection on the slat position fed back by one or more first position sensors 132 through an internal redundancy monitoring channel to ensure the integrity of the slat position signal.

[0041] The high-lift computer 330 may also provide the slat position signals of one or more channels (shown as the first slat position signals) to the control unit 320 of the main flight control system. By way of example and not limitation, the first slat position signal may indicate the position (or angle) of the slat. The main flight control system may also determine whether the slat is in the open state or the retracted state based on the first slat position signal. The control law of the main flight control system will calculate the control commands for the control surfaces of the aircraft in different configurations according to these two states.

[0042] The main flight control system may include a main flight control computer 310, a control unit 320, and a second position sensor 311. The second position sensor 311 may be independent of the first position sensor 332 and may be installed on the same or different slat airfoils as the first position sensor 332. By way of example and not limitation, an associated second position sensor 311 may be provided on a selected single airfoil. In other embodiments, a plurality of redundant second position sensors 311 may be provided on a plurality of selected airfoils. The second position sensor 311 may generate a slat position signal (e.g., a slat discrete signal, shown as the second slat position signal) based on the detected slat position, and the slat position signal may be transmitted to the control unit 320. By way of example and not limitation, the control unit 320 may be implemented by devices such as a computer, a processor, a controller, an integrated circuit, a programmable device, etc.

[0043] When the main flight control computer 310 is operating normally, the control unit 320 can transmit the slat position signal received from the high-lift system (e.g., the high-lift computer 330) (hereinafter referred to as the first slat position signal for example) to the main flight control computer 310. The main flight control computer 310 can perform control law calculations and generate control commands based on the operation input signals from the control devices (e.g., the control column, the steering wheel, and the pedals, etc.) and the first slat position signal. The control command can be provided to the control unit 320, and the control unit 320 generates a control surface command based on the control command to control the movement of the control surfaces of the aircraft. By way of example and not limitation, the control surfaces of the aircraft can include the elevator surface, the horizontal stabilizer surface, the rudder, the spoiler, the aileron, etc. When the main flight control computer 310 is operating normally, the slat position signal provided by the second position sensor 311 may not be used for control surface control.

[0044] According to one embodiment, the control devices (e.g., the control column, the steering wheel, and the pedals, etc.) can send operation input signals to the control unit 320, and then the control unit 320 transmits the operation input signals to the main flight control computer 310. In an alternative embodiment, the main flight control computer 310 can correct the operation input signals of the control devices according to the state of the aircraft (e.g., attitude, speed, angle of attack, the position of the flaps and slats, etc.) and generate control commands using the corrected operation input signals. The control command can be sent back to the control unit 320 to control the movement of the control surfaces.

[0045] The high-lift computer 330 can detect signal faults of the slat position feedback by the first position sensor 332 through an internal redundant monitoring channel, for example, comparing and monitoring the slat positions detected by monitoring channel 1 and monitoring channel 2 to ensure the integrity of the slat position signal. In addition, the main flight control computer 310 can also receive the multi-channel slat position data of the high-lift computer 330 and identify faults by comparison and other means. If it is determined that there is a fault in the first slat position signal, the main flight control computer 310 can reconstruct the control law based on the previously valid first slat position signal, thereby generating a correct control command. The main flight control computer will record the slat signal value of the last frame of the high-lift system that can pass the comparison monitoring (i.e., the first slat state position signal).

[0046] On the other hand, when the main flight control computer 310 is operating normally, it can monitor the faults of the slat position signal provided by the second position sensor 311.

[0047] In one embodiment, the control unit 320 may provide a first slat position signal and a second slat position signal to the primary flight control computer 310, and the primary flight control computer 310 determines whether the second position sensor 311 is faulty based on a comparison between the first slat position signal and the second slat position signal. For example, when the difference between the first slat position signal and the second slat position signal exceeds a threshold (e.g., indicating that the slat positions detected by the first position sensor 332 and the second position sensor 311 differ by more than the threshold), it may be determined that the second position sensor 311 is faulty.

[0048] In another embodiment, when the primary flight control computer 310 is operating normally, the control unit 320 may generate a first slat status signal based on the first slat position signal and generate a second slat status signal based on the second slat position signal, where the first slat status signal and the second slat status signal each indicate whether the slat is in an open state or a retracted state. The control unit 320 may provide the first slat status signal and the second slat status signal to the primary flight control computer 310. Alternatively, the primary flight control computer 310 may generate a first slat status signal based on the first slat position signal and generate a second slat status signal based on the second slat position signal. The primary flight control computer 310 may determine whether the second position sensor is faulty by comparing the first slat status signal with the second slat status signal. For example, if the first slat status signal and the second slat status signal indicate different states (open state or retracted state) for a period longer than a threshold time period, it may be considered that the second position sensor is faulty.

[0049] That is, when the primary flight control computer 310 is operating normally, it may use the first slat position signal of the high-lift computer 330 to monitor the second slat position signal to prevent potential faults of the second position sensor (or the second slat position signal). When it is determined that the second position sensor 311 is faulty, a fault report may be made, or the second position sensor 311 may be repaired, or the faulty second position sensor 311 may be disabled.

[0050] Figure 4 A schematic block diagram of a primary flight control system according to another embodiment of the present invention is shown. Figure 4 The slat signal flow when the primary flight control computer fails is also shown.

[0051] As described above, based on the slat position information provided by the first position sensor 332, the high-lift computer 330 may provide a first slat position signal to the control unit 320 of the primary flight control system. The second position sensor 311 may generate a second slat position signal (e.g., a slat discrete signal) based on the detected slat position, and the second slat position signal may be transmitted to the control unit 320.

[0052] When the main flight control computer 310 fails, the main flight control computer 310 can no longer provide control commands to the control unit 320, and the main flight control system will enter the direct control mode. For example, when the main flight control computer 310 fails to send a signal due to a fault, the control unit 320 will not receive an instruction from the main flight control computer 310, thereby determining that the main flight control computer 310 has failed. In an example with multiple main flight control computers, if one of the main flight control computers sends an incorrect signal, since the computers are redundantly configured, the control unit 320 can determine the faulty computer through data comparison among multiple computers. If multiple main flight control computers connected to the control unit 320 all fail simultaneously and the control unit 320 cannot receive a valid main flight control computer signal, the main flight control system will enter the direct control mode.

[0053] In the direct control mode, the control unit 320 can generate a control surface command based on the flap position signal provided by the second position sensor 311 together with the operation input signal from the control devices (such as the joystick, steering wheel, and pedals, etc.) to control one or more control surfaces of the aircraft. At the same time, in the direct control mode, the control unit 320 does not use the first flap position signal provided by the high-lift computer 330. By way of example and not limitation, in the direct control mode, the control unit 320 can generate a control surface command through "joystick command * gain = control surface deflection angle". The control surface command can be based on this control surface deflection angle and can indicate the angle by which the corresponding control surface needs to deflect. The gain can be selected according to the open / retract state of the flap position signal (e.g., through look-up tables, mapping, calculations, etc.). The gain can be larger when the flap is open and smaller when the flap is retracted. By way of example and not limitation, the specific value of the gain can be calibrated according to experience, wind tunnel models, and other means.

[0054] In other embodiments, the control unit 320 can use other calculation methods to generate a control surface command based on the operation input signal in the direct mode, where the first flap position signal (or the flap state indicated thereby) can be used as a calculation parameter. By way of example and not limitation, the control unit can determine the gain corresponding to the first flap position signal (e.g., the flap angle indicated thereby) and generate a control surface command through "joystick command * gain = control surface deflection angle". In this case, different flap angles (or flap angle ranges) can correspond to different gains, and it may not be necessary to separately generate a flap state signal.

[0055] Thus, when the main flight control computer loses its fault detection ability, a flap position signal is provided by an independent flap position detection device, thereby getting rid of the dependence on the high-lift computer and avoiding a catastrophic failure where the control surface deflects incorrectly due to a single-point failure of the high-lift computer.

[0056] The main flight control system according to the present invention has at least the following potential advantages.

[0057] 1) An independent slat position detection device (e.g., the second position sensor 311) is used to provide the slat position signal. This detection device is independent of the high-lift system, which solves the problem that in the direct control mode of the main flight control, due to the error probability of the slat discrete signal sent by the high-lift computer not meeting 1e-9 / FH and the main flight control computer being unable to perform comparison and monitoring, the error signal may cause the control surface to deflect incorrectly, resulting in a catastrophic accident. This solution can meet the safety requirements without changing the architectures of the main flight control computer and the high-lift computer.

[0058] 2) The high-lift computer can analyze the integrity of the slat position signal and select a high-integrity signal (the first slat position signal) to provide to the main flight control computer. The main flight control computer can compare the first slat position signal with the second slat position signal provided by the second position sensor through the trigger timing to achieve fault monitoring of the second position sensor, thereby reducing the logical complexity. Since the slat signal provided by the high-lift computer has an integrity higher than 1e-9 / FH under system monitoring when there is no common-mode fault, the confidence in monitoring the second position sensor 311 through the slat position signal provided by the high-lift computer is relatively high in general, which can prevent potential faults of the second slat position signal, thus ensuring that once entering the direct control mode (the main flight control computer is not used), no faults will be caused by errors in the second position sensor.

[0059] 3) Even if a common-mode error occurs in the high-lift computer, the error probability of the independent sensor in the present invention is less than 1e-7 / FH, and it is a simple electromechanical product without single-point common-mode faults; while the probability of the main flight control system entering the direct control mode is 1e-6 / FH, so the probability of the sensor making an error after entering the direct control mode is also far less than 1e-9 / FH, which can meet the requirements for catastrophic fault probability.

[0060] Figure 5 The installation schematic diagram of the slat position sensor of the main flight control system according to an embodiment of the present invention is shown. The slat position sensor can be, for example, the second position sensor 311 described above. By way of example and not limitation, the second position sensor 311 can be installed on a selected wing surface, such as the left outboard slat, the left inboard slat, the right outboard slat, or the right inboard slat. In other embodiments, multiple redundant second position sensors 311 can be provided on multiple selected wing surfaces. The second position sensor 311 can be a single-channel or multi-channel position sensor. For a multi-channel position sensor, multiple channels can be checked against each other, and / or each channel can be used to control different control surfaces.

[0061] In a preferred embodiment of the present invention, the second position sensor 311 may be a Rotary Variable Differential Transformer (RVDT). The RVDT may be a dual-channel or quad-channel slat position sensor. The RVDT may be driven by a rack and pinion. The rack may be installed on the slat structure slide rail. The radius and arc length of the rack are determined according to the stroke and angle of the high-lift wing surface movement. The RVDT is installed on the airframe structure (e.g., structural rib) and meshes with the rack.

[0062] When the wing surface starts to move, the wing surface drives the rack to move, and the rack drives the sensor to move, converting the movement angle of the high-lift slat into the movement of the sensor driven by the rack, and detecting the movement angle θ of the RVDT. The sensor can be calibrated according to the theoretical wing surface geometric angle designed for the aircraft to establish the relationship between the RVDT movement angle θ and the wing surface movement angle a, so as to obtain the angle of the control surface (i.e., the wing surface position).

[0063] For example, the relationship between the RVDT angle θ and the wing surface movement angle a can be established as shown in Equation 1:

[0064] a = kθ + a0....................................................... Equation 1

[0065] Where k is the geometric linear relationship between the two, and a0 is the position of the wing surface when the RVDT is at 0°.

[0066] Using the RVDT sensor to detect the extended or retracted position of the wing surface is lightweight, small in size, and highly reliable. In addition, the rack and pinion drive has a short transmission line system, small clearance, good linearity, and high precision.

[0067] The first position sensor of the high-lift system may also use an RVDT sensor. In other embodiments, the first position sensor and the second position sensor may each use other types of position sensors, such as but not limited to linear displacement sensors, cable-type position sensors, optical encoder sensors, etc.

[0068] Figure 6 A schematic diagram of generating a slat state signal according to an embodiment of the present invention is shown.

[0069] When the control unit 320 receives the slat position (e.g., slat angle) generated by the second position sensor 311 and / or the first slat position signal of the high-lift system, it can be based on Figure 6 perform conversion to generate a slat state signal. The slat state signal can indicate that the slat is in the open state or the retracted state. The main flight control system control law can calculate the control commands for different configurations of the aircraft according to these two states.

[0070] When the slat angle reaches trigger point 1, the slat status signal will switch from slat retracted (marked as 0) to slat extended (marked as 1); when the slat angle reaches trigger point 2, the slat status signal will switch from extended (marked as 1) to slat retracted (marked as 0). When setting the trigger points, the error a of the position sensor can also be considered. tor Set a lead to ensure the accuracy of the status signal. For example, during the slat lowering process, the trigger point can be a - a. tor And during the slat retracting process, the trigger point can be a + a. tor .

[0071] In some embodiments according to Figure 6 , the degree of slat extension can also be determined based on the slat position signal, such as the positions: position 1, position 2, position 3, position 4, etc. The main flight control computer or the control unit can control the movement of the control surface based on the specific degree of slat extension.

[0072] It should be understood that although Figure 6 shows that the control unit 320 converts the slat position signal into a slat status signal indicating the extended state or the retracted state, this conversion operation can also be implemented by other devices, such as the high-lift computer, the main flight control computer, etc.

[0073] Figure 7 shows a schematic diagram of the slat status signal fault monitoring logic according to an embodiment of the present invention. This fault monitoring logic can be implemented by the main flight control computer 310 when it is operating normally.

[0074] To ensure the correctness of the slat position signal generated by the second position sensor 311, fault detection can be performed by comparing it with the slat status signal sent by the high-lift computer 330.

[0075] The state switching time of the slat position signal sent by the second position sensor 311 can be compared with the state switching time of the first slat position signal sent by the high-lift computer. If the time difference between the two signal switches exceeds the slat retraction / extension time (threshold Y), it can be considered that the second slat status signal is faulty.

[0076] For example, the main flight control computer 310 can determine the first state switching time when the first slat position signal from the high-lift system changes its state (for example, from the retracted state to the extended state, or from the extended state to the retracted state).

[0077] The main flight control computer 310 may also determine a second state transition time when the second flap position signal undergoes the same state change, and compare the first state transition time with the second state transition time. If the difference between the first state transition time and the second state transition time exceeds a threshold, it may be determined that the second flap state signal has failed.

[0078] In an alternative embodiment, it is also possible to monitor for faults in the position sensor itself (e.g., the second position sensor 311). For example, due to the physical characteristics of the RVDT sensor itself, the sum of the voltages Va and Vb of the two-stage coil output voltage is fixed. If it is too high or too low, it can be determined that the RVDT has a short circuit or an open circuit. Therefore, the effectiveness of the RVDT sensor itself can be monitored through this characteristic. In a further aspect, an independent sensor can be used in combination with a logical comparison of the flap position signal sent by the high-lift computer and self-monitoring of the sensor for fault monitoring.

[0079] Figure 8 A flowchart of a control method 800 of a main flight control system according to an embodiment of the present invention is shown. The control method 800 may be executed by a main flight control system (e.g., the main flight control computer 310 and / or the control unit 320).

[0080] In block 801, a first flap position signal is received from the high-lift system. The first flap position signal may be generated based on the flap position detected by a first position sensor mounted on the flap associated with the high-lift system.

[0081] In block 802, a second flap position signal detected by a second position sensor mounted on the flap is received. The second position sensor may be independent of the first position sensor and may be mounted on the same or a different wing surface as the first position sensor. Each of the first position sensor and the second position sensor may include one or more of the following: a rotary variable differential transformer, a linear displacement sensor, a cable type position sensor, an optical encoder sensor, etc.

[0082] In block 803, it may be determined whether the main flight control computer is operating normally. When the main flight control computer is operating normally, it exchanges data with the control unit. If the control unit does not receive a signal from the main flight control computer, it will be determined that it is not operating normally.

[0083] When the main flight control computer is operating normally, in optional block 804, it may be determined whether there is a fault in the second flap position signal (or the second position sensor) based on the first flap position signal.

[0084] In one embodiment, the primary flight control computer may determine whether a second position sensor is faulty based on a comparison between a first slat position signal and a second slat position signal. For example, if the difference between the first slat position signal and the second slat position signal exceeds a first threshold, it may be determined that the second position sensor is faulty.

[0085] In another embodiment, it may be determined whether the second position sensor is faulty based on whether the first slat position signal and the second slat position signal indicate the same slat state. For example, a first slat state signal may be generated based on the first slat position signal and a second slat state signal may be generated based on the second slat position signal, where the first slat position signal and the second slat state signal each indicate that the slat is in an open state or a retracted state. In one example, it may be determined whether the first slat state signal and the second slat state signal indicate the same state, and if the first slat state signal and the second slat state signal indicate different states for a threshold time period or more, it may be determined that the second position sensor is faulty. In another example, a first state transition time at which the first slat state signal changes state and a second state transition time at which the second slat state signal changes state may be determined, and if the difference between the first state transition time and the second state transition time exceeds a second threshold, it may be determined that the second position sensor is faulty.

[0086] At block 805, when the primary flight control computer is operating normally, the primary flight control computer generates a control command based on an operation input signal from a control device and a first slat position signal, and a control surface command is generated by a control unit based on the control command to control one or more control surfaces of the aircraft. The control unit may generate corresponding control surface commands for different control surfaces. The one or more control surfaces include one or more of the following: elevator, horizontal stabilizer, rudder, spoiler, aileron.

[0087] In addition, when operating normally, the primary flight control computer determines whether the first slat position signal is faulty by comparing multiple first slat position signals received from multiple channels of the high-lift system. If the first slat position signal is faulty, the primary flight control computer generates a control command based on the previous last valid first slat position signal to control one or more control surfaces of the aircraft.

[0088] When the primary flight control computer fails, at block 806, the control unit generates a control surface command based on the operation input signal and the second slat position signal to control the one or more control surfaces of the aircraft. For example, the control unit may generate a second slat state signal based on the second slat position signal, the second slat state signal indicating that the slat is in an open state or a retracted state, and the control unit generates a control surface command based on the operation input signal from the control device and a gain corresponding to the second slat state signal.

[0089] The present invention provides a main flight control system for an aircraft and a control method thereof. The main flight control system according to the present invention can adopt an independent detection device to provide a slat position signal, and further can perform fault monitoring based on a redundancy management algorithm for integrity analysis. When the main flight control computer is working properly, the main flight control system uses the slat position signal sent by the high-lift computer for control. At this time, the main flight control computer can perform fault monitoring and detect the slat signal fault in time. When the main flight control computer fails, the main flight control system enters the direct control mode and uses an independent slat position sensor to provide a slat signal for flap control. The failure probability of the independent sensor itself is less than 1e-5 / FH, there is no single-point fault, and it is independent of the slat position signal sent by the high-lift calculation, meeting the safety requirements.

[0090] The numerical values given in the embodiments are only examples and do not limit the scope of the present invention. The thresholds used in the various embodiments may be the same or different, and appropriate thresholds can be selected according to the specific implementation. In addition, as an overall technical solution, there are other components or steps that are not listed in the claims or the specification of the present invention. Moreover, the single name of a component does not exclude other names of the component.

[0091] In the description of the present application, the orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", "inner, outer", etc. usually refer to the orientation or position relationship shown in the drawings. They are only for the convenience of describing the present application and simplifying the description. Without contrary instructions, these orientation terms do not indicate and imply that the device or component referred to must have a specific orientation or be constructed and operated in a specific orientation, so they cannot be understood as limiting the protection scope of the present application.

[0092] For the convenience of description, spatial relative terms such as "above...", "above...", "on the upper surface of...", "upper" etc. can be used here to describe the spatial position relationship between a device or feature shown in the figure and other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation other than the orientation described in the figure of the device.

[0093] In addition, it should be noted that using ordinal terms such as "first", "second", etc. to limit components is only for the convenience of distinguishing the corresponding components. Without additional statements, the above terms have no special meaning, so they cannot be understood as limiting the protection scope of the present application.

[0094] The various steps and modules of the methods and apparatuses described above can be implemented in hardware, software, or a combination thereof. If implemented in hardware, the various illustrative steps, modules, and circuits described in connection with the present disclosure can be implemented or executed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic components, hardware components, or any combination thereof. The general-purpose processor can be a processor, a microprocessor, a controller, a microcontroller, or a state machine, etc. If implemented in software, the various illustrative steps and modules described in connection with the present disclosure can be stored on or transmitted as one or more instructions or codes on a computer-readable medium. The software modules for implementing the various operations of the present disclosure can reside in a storage medium such as RAM, flash memory, ROM, EPROM, EEPROM, registers, a hard disk, a removable disk, a CD-ROM, cloud storage, etc. The storage medium can be coupled to the processor so that the processor can read from / write to the storage medium and execute the corresponding program modules to implement the various steps of the present disclosure. Moreover, the software-based embodiments can be uploaded, downloaded, or remotely accessed by appropriate communication means. Such appropriate communication means include, for example, the Internet, the World Wide Web, an intranet, a software application, a cable (including an optical fiber cable), magnetic communication, electromagnetic communication (including RF, microwave, and infrared communication), electronic communication, or other such communication means.

[0095] It should also be noted that these embodiments may be described as processes depicted as flowcharts, flow diagrams, structural diagrams, or block diagrams. Although a flowchart may describe the operations as a sequential process, many of these operations can be performed in parallel or concurrently. Additionally, the order of these operations can be rearranged.

[0096] The disclosed methods, apparatuses, and systems should not be limited in any way. Instead, the present disclosure encompasses all novel and non-obvious features and aspects of the various disclosed embodiments (individually and in various combinations and sub-combinations with each other). The disclosed methods, apparatuses, and systems are not limited to any specific aspect or feature or their combination, and any disclosed embodiment does not require the presence of any one or more specific advantages or the solution of specific or all technical problems.

[0097] The present invention is not limited to the specific embodiments described above. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit of the present invention and the scope protected by the claims. All of these fall within the scope of protection of the present invention.

Claims

1. A main flight control system for an aircraft, characterized in that, Comprising: A control unit, which is connected to a high-lift system to receive a first slat position signal from the high-lift system, the first slat position signal being generated based on the slat position detected by a first position sensor mounted on the slat associated with the high-lift system; A second position sensor mounted on the slat, which is configured to generate a second slat position signal based on the detected slat position, wherein the control unit also receives the second slat position signal, the control unit generates a first slat state signal based on the first slat position signal and generates a second slat state signal based on the second slat position signal, wherein the first slat state signal and the second slat state signal each indicate that the slat is in an open state or a retracted state; and A primary flight control computer connected to the control unit, wherein when the primary flight control computer is operating normally, the primary flight control computer generates a control command based on an operation input signal from a control device and the first slat position signal, and the control unit generates a control surface command based on the control command to control one or more control surfaces of the aircraft, wherein when the primary flight control computer is operating normally, it determines whether the first slat state signal and the second slat state signal indicate the same state, and if the first slat state signal and the second slat state signal indicate different states for more than a threshold time period, it determines that the second position sensor is faulty, or wherein when the primary flight control computer is operating normally, it determines a first state switching time when the first slat state signal changes state and a second state switching time when the second slat state signal changes state, and if the difference between the first state switching time and the second state switching time exceeds a threshold, it determines that the second position sensor is faulty, wherein when the primary flight control computer is operating normally, it determines whether the first slat position signal is faulty by comparing multiple first slat position signals received by the control unit from multiple channels of the high-lift system, and if the first slat position signal is faulty, the primary flight control computer generates a control command based on the previous last valid first slat position signal to control the one or more control surfaces of the aircraft, wherein when the primary flight control computer fails, the control unit generates a control surface command based on the operation input signal and the second slat position signal to control the one or more control surfaces of the aircraft.

2. The primary flight control system according to claim 1, characterized in that: when the primary flight control computer is operating normally, the primary flight control computer determines whether the second position sensor is faulty based on a comparison of the first slat position signal and the second slat position signal.

3. The main flight control system according to claim 1, characterized in that The control unit generating a control surface command based on the operation input signal and the second slat position signal includes: the control unit generates a control surface command based on the operation input signal from the control device and a gain corresponding to the second slat state signal.

4. The main flight control system according to claim 1, wherein: The one or more control surfaces include one or more of the following: elevator surface, horizontal stabilizer surface, rudder, spoiler, aileron.

5. The main flight control system according to claim 1, wherein: Each of the first position sensor and the second position sensor includes one or more of the following: rotational differential position sensor, linear displacement sensor, cable type position sensor, optical encoder sensor.

6. An aircraft, characterized in that, Comprising: A high-lift system; And The main flight control system according to any one of claims 1-5.

7. A control method for a main flight control system of an aircraft, characterized in that, Comprising: Receiving a first slat position signal from the high-lift system, the first slat position signal being generated based on the slat position detected by a first position sensor mounted on the slat associated with the high-lift system; Receiving a second slat position signal detected by a second position sensor mounted on the slat; Generating a first slat status signal based on the first slat position signal and generating a second slat status signal based on the second slat position signal, wherein each of the first slat status signal and the second slat status signal indicates that the slat is in an open state or a retracted state; Determining whether the first slat status signal and the second slat status signal indicate the same state, if the first slat status signal and the second slat status signal indicate different states for more than a threshold time period, then determining that the second position sensor has a fault, or determining a first state switching time when the first slat status signal changes state, and a second state switching time when the second slat status signal changes the state, if the difference between the first state switching time and the second state switching time exceeds a threshold, then determining that the second position sensor has a fault; When the main flight control computer is operating normally, the main flight control computer generates a control command based on an operation input signal from a control device and the first slat position signal, and a control surface command is generated by a control unit based on the control command to control one or more control surfaces of the aircraft, wherein when operating normally, the main flight control computer determines whether the first slat position signal has a fault by comparing multiple first slat position signals received from multiple channels of the high-lift system, if the first slat position signal has a fault, then the main flight control computer generates a control command based on the previous last valid first slat position signal to control the one or more control surfaces of the aircraft; And When the main flight control computer fails, the control unit generates a control surface command based on the operation input signal and the second slat position signal to control the one or more control surfaces of the aircraft.

8. The control method according to claim 7, wherein: When the main flight control computer is operating normally, the main flight control computer determines whether the second position sensor has a fault based on a comparison between the first slat position signal and the second slat position signal.

9. The control method according to claim 7, characterized in that, The control unit generating a control surface command based on the operation input signal and the second slat position signal includes: The control unit generates a control surface command based on the operation input signal from the control device and a gain corresponding to the second slat state signal.

10. The control method according to claim 7, wherein: The one or more control surfaces include one or more of the following: elevator surface, horizontal stabilizer surface, rudder, spoiler, aileron.

11. The control method according to claim 7, wherein: Each of the first position sensor and the second position sensor includes one or more of the following: rotary differential position sensor, linear displacement sensor, cable type position sensor, optical encoder sensor.

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