A method for switching dual-channel working modes of a FADEC system

Abstract

The application relates to the technical field of aero-engine control system architecture design, and particularly discloses a FADEC system double-channel working mode switching method, which comprises the following steps: obtaining a current output instruction of a first control channel and a current output instruction of a second control channel in a FADEC system; calculating an output similarity between the two control channels according to the current output instruction of the first control channel and the current output instruction of the second control channel; controlling a current working mode of the FADEC system according to the output similarity between the two control channels; and controlling a current working state of the first control channel and a current working state of the second control channel according to the current working mode of the FADEC system. The application can evaluate the similarity of the double channels according to the system output instructions of the channels, accurately determine whether the states of the double channels are consistent, select a suitable system and channel working mode, and ensure that the FADEC system is safe and reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine control system architecture design, and particularly relates to a FADEC system dual-channel working mode switching method. BACKGROUND

[0002] A full authority digital electronic control (FADEC) system adjusts system control output in real time according to operation instructions of an aircraft, and ensures that an engine working state meets flight requirements, and is a core component of an aero-engine. In order to improve safety and reliability of the FADEC system, and avoid abnormal reduction of the engine state caused by a single point fault in the system, the FADEC system is generally designed as a dual-redundancy architecture, each redundancy corresponds to a control channel, and each channel is provided with independent sensors, signal processing units, control calculation units, output distribution units and actuators, and can independently realize complete engine control functions.

[0003] Ideally, in the dual-redundancy architecture of the FADEC system, each channel participates in control together, raw signals collected by the sensors of each channel are processed after calibration, filtering, fault diagnosis and the like, information interaction between channels is performed, and final effective inputs are obtained, a control law calculation unit calculates according to the effective inputs and a predetermined control law, and obtains all output instructions required by the system, and an output distribution unit distributes output instructions to be borne by the channel according to system output instructions and running conditions of each channel, the system can reconstruct any control loop, and ensures that the system always has complete functions, and does not affect engine control effect due to a single point fault.

[0004] The main problem of the architecture is that: in order to control the engine in an expected state, it is necessary to ensure that the states of two channels are consistent, when a single-channel reset, transient calculation error and the like cause a large deviation between the states of two channels, the two channels cannot control the engine in the expected state, and in a serious case, the FADEC system misjudges system failure or even engine failure, causes abnormal reduction of the engine state, and endangers flight safety. SUMMARY

[0005] In order to solve the problem that the dual-channel architecture of the FADEC system cannot effectively identify system working abnormalities, and causes the engine state to not meet expectations, the present application provides a FADEC system dual-channel working mode switching method, which can evaluate similarity of two channels according to system output instructions of each channel, accurately judge whether the states of two channels are consistent, and select appropriate system and channel working modes, and ensure safe and reliable working of the FADEC system.

[0006] As a first aspect of the present application, a FADEC system dual-channel working mode switching method is provided, the FADEC system comprising a first control channel and a second control channel, the FADEC system dual-channel working mode switching method comprising:

[0007] Step S1: obtaining a current output instruction of the first control channel and a current output instruction of the second control channel in the FADEC system;

[0008] Step S2: calculating an output similarity S_out between the two control channels according to the current output instruction of the first control channel and the current output instruction of the second control channel;

[0009] Step S3: controlling a current working mode of the FADEC system according to the output similarity S_out between the two control channels;

[0010] Step S4: controlling a current working state of the first control channel and a current working state of the second control channel according to the current working mode of the FADEC system.

[0011] Further, the calculation of the output similarity between the two control channels according to the current output instruction of the first control channel and the current output instruction of the second control channel further comprises:

[0012] For a FADEC system with n output instructions for each of the two control channels, the output similarity S_out between the two control channels in the FADEC system is defined according to formula (1);

[0013]

[0014]

[0015] wherein i represents the i-th output instruction of each control channel in the FADEC system; d i is the i-th normalized output instruction deviation, for the i-th output instruction of each control channel in the FADEC system, sA i , sB i are the i-th output instruction of the first control channel and the i-th output instruction of the second control channel, respectively, s i is a normalization parameter; m i is the weight of the i-th normalized output instruction deviation d i .

[0016] Further, the control of the current working mode of the FADEC system according to the output similarity between the two control channels further comprises:

[0017] If the output similarity S_out between two control channels is less than 1, it is considered that the two control channels of the FADEC system are dissimilar, otherwise, it is considered that the two control channels of the FADEC system are similar;

[0018] When the two control channels of the FADEC system are dissimilar and last for a certain time, the current working mode of the FADEC system is controlled to be the single-channel dominant control mode;

[0019] When the two control channels of the FADEC system are similar and last for a certain time, and the engine working state is stable, the current working mode of the FADEC system is controlled to be the double-channel common control mode.

[0020] Further, the controlling the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system further comprises:

[0021] When the current working mode of the FADEC system is the single-channel dominant control mode, the current health degree of the first control channel and the current health degree of the second control channel are obtained, and the current health degrees of the two control channels are compared, the control channel with better health degree is the dominant control channel, and the other control channel is the following control channel; wherein, the dominant control channel and the following control channel both output according to the output instruction of the dominant control channel.

[0022] Further, the controlling the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system further comprises:

[0023] When the current working mode of the FADEC system is the double-channel common control mode, the two control channels in the FADEC system are controlled to be dominant control channels, wherein the two dominant control channels respectively output according to their own output instructions.

[0024] Further, it further comprises:

[0025] If the current dominant control channel fails to cause the engine working state to degrade, the control channel is controlled to degrade to the following control channel, and the other control channel is switched to the dominant control channel, so as to ensure that the FADEC system always runs in a safe state.

[0026] Further, the comparing the current health degrees of the two control channels further comprises:

[0027] According to the maximum thrust or power level allowed by the current control channel to the engine, the current health degrees of the two control channels are compared;

[0028] Among them, the control channel allowing the maximum thrust or power level provided by the engine to be higher is the leading control channel, and the other control channel is the following control channel.

[0029] The FADEC system dual-channel working mode switching method provided by the application has the following advantages:

[0030] 1. The application effectively identifies the channel state inconsistency hidden danger caused by abnormality in the working process of the FADEC system dual-channel architecture, timely switches the working mode of the FADEC system and the channel itself, avoids the engine working in an unintended state, and affects flight safety;

[0031] 2. The application only changes the output result of the control calculation unit in the FADEC system architecture, always uses the dual-channel sensors, signal processing units, output distribution units and actuators to participate in control, maximizes the use of control resources in the system, and avoids single-point failure causing engine control abnormality;

[0032] 3. The dual-channel similarity evaluation algorithm proposed by the application only uses the output result of the control calculation unit, the interface is clear, the content is fixed, and it does not involve numerous intermediate variables in the control calculation unit, which reduces the development cost when the control law is upgraded and iterated, and is beneficial to improve the reliability and maintainability of the system throughout its life cycle. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the application, and constitute a part of the specification, and together with the following specific embodiments, are used to explain the application, but do not constitute a limitation on the application.

[0034] Figure 1 The principle diagram of the FADEC system dual-channel common control mode provided by the application.

[0035] Figure 2 The principle diagram of the FADEC system single-channel leading control mode provided by the application.

[0036] Figure 3 The flowchart of the FADEC system dual-channel working mode switching method provided by the application.

[0037] Figure 4 The specific embodiment flowchart of the FADEC system dual-channel working mode switching method provided by the application. DETAILED DESCRIPTION

[0038] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0039] In order to make the technical scheme of the present application better understood, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should belong to the scope of protection of the present application.

[0040] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0041] The principle of the dual-channel operation of the FADEC system is shown in Figure 1 、 Figure 2 Each channel of the FADEC system is equipped with an independent sensor, and the raw input signals collected by the sensor are processed in the signal processing unit and interacted between channels to obtain consistent effective input signals; the effective input signals enter the control calculation unit to obtain system output instructions; the system output instructions are interacted between channels in the output distribution unit to determine the channel output results according to the control mode of each channel, and finally the two channel outputs jointly act on the actuator to realize the control of the engine.

[0042] The system operating modes include:

[0043] 1) Dual-channel common control mode: the two channels of the FADEC system have the same priority and jointly participate in control, as shown in Figure 1 .

[0044] 2) Single-channel dominant control mode: the FADEC system uses the system output instruction of a certain channel preferentially, and the other channel is used as a following channel, which uses the system output instruction of the other channel, as shown in Figure 2 .

[0045] The channel operating states include:

[0046] 1) Dominant control: output distribution according to the output instruction of the self channel;

[0047] 2) Following control: output distribution according to the output instruction of the other channel.

[0048] The embodiment provides a FADEC system double-channel working mode switching method, Figure 3 The embodiment provides a FADEC system double-channel working mode switching method, Figure 3 The embodiment provides a FADEC system double-channel working mode switching method,

[0049] Step S1: obtaining current output instructions of a first control channel and current output instructions of a second control channel in the FADEC system;

[0050] Step S2: calculating output similarity S_out between the two control channels according to the current output instructions of the first control channel and the current output instructions of the second control channel;

[0051] Ideally, the double-channel state in the FADEC system is consistent, and the system output instructions are also consistent. When the system output instructions have a long-time difference, it is considered that the system is abnormal, and when the difference between the double-channel system output instructions is small and lasts for a certain time, it is considered that the system returns to normal, and the specific process is as follows:

[0052] Preferably, the calculating output similarity S_out between the two control channels according to the current output instructions of the first control channel and the current output instructions of the second control channel further includes:

[0053] For the FADEC system with n output instructions of the two control channels, the output similarity S_out between the two control channels in the FADEC system is defined according to formula (1).

[0054]

[0055]

[0056] Wherein, i represents the i th output instruction of each control channel in the FADEC system; d i is the i th normalized output instruction deviation, for the i th output instruction of each control channel in the FADEC system, sA i , sB i are the i th output instruction of the first control channel and the i th output instruction of the second control channel, s i is a normalization parameter; m i is the weight of the i th normalized output instruction deviation d i Generally speaking, the greater the output instruction affecting the system, the greater the corresponding weight.

[0057] Step S3: controlling the current working mode of the FADEC system according to the output similarity S_out between the two control channels;

[0058] Preferably, as shown in Figure 4 the step of controlling the current working mode of the FADEC system according to the output similarity between the two control channels further comprises:

[0059] If the output similarity S_out between the two control channels is less than 1, it is considered that the two control channels of the FADEC system are dissimilar, otherwise, it is considered that the two control channels of the FADEC system are similar;

[0060] Ideally, the two channels of the FADEC system are consistent and participate in control together, when the two channels are different, it indicates that the FADEC system is abnormal, and the single channel dominant control is required to ensure the safety of the system, and when the two channel outputs are consistent again and the engine working state is stable, the two channels participate in control together, which is as follows:

[0061] When the two control channels of the FADEC system are dissimilar and last for a certain time, the current working mode of the FADEC system is controlled to be the single channel dominant control mode;

[0062] When the two control channels of the FADEC system are similar and last for a certain time, and the engine working state is stable (in the "allowed recovery state"), the current working mode of the FADEC system is controlled to be the two channel common control mode;

[0063] Otherwise, the system working mode remains unchanged.

[0064] Step S4: controlling the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system.

[0065] Ideally, each channel of the FADEC system allocates channel output according to the system output instruction calculated by itself, when the FADEC system is abnormal, an optimal channel is selected to dominate control, and both channels allocate according to the system output instruction of the dominant control channel, which is as follows:

[0066] Preferably, as shown in Figure 4 the step of controlling the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system further comprises:

[0067] When the current operating mode of the FADEC system is the single-channel dominant control mode, the current health of the first control channel and the current health of the second control channel are obtained, and the current health of the two control channels are compared, and the control channel with better health of the two control channels is used as the dominant control channel, and the other control channel is used as the follower control channel; wherein, the dominant control channel and the follower control channel both output according to the output instruction of the dominant control channel.

[0068] Among them, if the current dominant control channel fails and causes the engine operating state to degrade (causing the health of this channel to be worse than that of another channel), the current control channel is controlled to be downgraded to a follower control channel, and the other control channel is switched to the dominant control channel to ensure that the FADEC system always operates in a safe state.

[0069] Specifically, comparing the current health levels of the two control channels further includes:

[0070] The current health of the two control channels is compared based on the maximum thrust or power level that the current control channel allows the engine to provide; the control channel that allows the engine to provide a higher maximum thrust or power level is used as the leading control channel, and the other control channel is used as the following control channel.

[0071] It should be understood that the health of the control channels is divided into the following levels (from high to low priority) based on the maximum thrust or power level that the current channel allows the engine to provide:

[0072] 100% rated thrust / power;

[0073] 90% rated thrust / power;

[0074] 80% rated thrust / power;

[0075] 70% rated thrust / power;

[0076] 50% rated thrust / power;

[0077] 30% rated thrust / power;

[0078] 0 rated thrust / power.

[0079] Preferably, if Figure 4 As shown, the controlling the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system further includes:

[0080] When the current working mode of the FADEC system is the dual-channel common control mode, the two control channels in the FADEC system are controlled to be the leading control channels, and the two leading control channels respectively output according to respective output instructions.

[0081] In the embodiment of the present application, the FADEC system dual-channel working mode switching method based on output similarity includes dual-channel difference judgment, system working mode judgment and channel working state judgment. The FADEC system evaluates the similarity of the system output instructions of the two channels, judges whether the dual-channel state is consistent, if the dual-channel state is inconsistent, adjusts the system working mode and the channel working state, selects one channel as the leading control channel and the other channel as the following control channel, controls according to the system output instruction of the leading control channel, and ensures the certainty of the FADEC system output; if the current leading control channel fails to cause the engine state to degrade, the channel is degraded to the following control channel, and the other channel is adjusted to the leading control channel, to ensure that the FADEC system always operates in a safer state. When the dual-channel outputs are consistent, the dual-channel common control is restored at the appropriate time, at which the FADEC system uses dual-redundancy control resources, and has higher safety and reliability. The switching of the working mode only affects the selection of the system output instruction, and no matter what working mode the FADEC system is in, the sensors, signal processing units, output distribution units and actuators of the dual channels are used for control, to maximize the use of the redundancy resources of the system.

[0082] The FADEC system dual-channel working mode switching method provided by the present application can identify the abnormality of the dual-channel working in time by voting the system output instructions of the dual channels, switch the working modes of the system and the channels, and avoid the abnormality of the engine operation caused by the inconsistency of the dual-channel state. When the output instructions of the dual channels are restored to be consistent, the dual-channel common control can be restored at the appropriate time, to fully utilize the control resources of the dual channels and improve the safety and reliability of the system.

[0083] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also regarded as the protection scope of the present application.

Claims

1. A method for switching dual-channel working modes of a FADEC system, wherein the FADEC system includes a first control channel and a second control channel, characterized in that: The FADEC system dual-channel working mode switching method includes: Step S1: obtaining a current output instruction of a first control channel and a current output instruction of a second control channel in the FADEC system; Step S2: Calculate the output similarity between the two control channels based on the current output instruction of the first control channel and the current output instruction of the second control channel. ; Step S3: Based on the output similarity between the two control channels Controlling the current operating mode of the FADEC system; Step S4: controlling the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system; The step of calculating the output similarity between the two control channels based on the current output instruction of the first control channel and the current output instruction of the second control channel further includes: For both control channels there are n The output similarity between two control channels in a FADEC system with multiple output commands is defined as follows: ; （1） ， in, i Represents the i-th output instruction of each control channel in the FADEC system; For the i Normalized output command deviation, for each control channel in the FADEC system Output instructions, 、 The first control channel i output instruction, the second control channel i Output instructions, is the normalization parameter; For the i Normalized output instruction deviation The weight of The method of controlling the current operating mode of the FADEC system according to the output similarity between the two control channels further includes: If the output similarity between the two control channels , then the two control channels of the FADEC system are considered to be dissimilar, otherwise, the two control channels of the FADEC system are considered to be similar; When the two control channels of the FADEC system are dissimilar and the dissimilarities last for a certain period of time, the current working mode of the FADEC system is the single-channel dominant control mode; When the two control channels of the FADEC system are similar for a certain period of time and the engine operating state is stable, the current operating mode of the FADEC system is the dual-channel common control mode; The controlling of the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system further includes: When the current operating mode of the FADEC system is a single-channel dominant control mode, obtaining the current health of the first control channel and the current health of the second control channel, comparing the current health of the two control channels, and selecting the control channel with better health as the dominant control channel, while the other control channel is designated as the follower control channel; wherein both the dominant control channel and the follower control channel perform output according to the output instruction of the dominant control channel; The controlling of the current working state of the first control channel and the current working state of the second control channel according to the current working mode of the FADEC system further includes: When the current working mode of the FADEC system is the dual-channel common control mode, the two control channels in the FADEC system are both dominant control channels, wherein the two dominant control channels respectively output according to their respective output instructions.

2. The FADEC system dual-channel working mode switching method according to claim 1, characterized in that: Also includes: If a fault occurs in the current dominant control channel, causing the engine operating state to degrade, the current control channel is controlled to be degraded to a follower control channel, and another control channel is switched to the dominant control channel to ensure that the FADEC system always operates in a safe state.

3. The FADEC system dual-channel working mode switching method according to claim 1, characterized in that: The comparing the current health status of the two control channels further includes: comparing the current health of the two control channels based on the maximum thrust or power level that the current control channels allow the engines to provide; Among them, the control channel that allows the engine to provide a higher maximum thrust or power level is used as the dominant control channel, and the other control channel is used as the following control channel.

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