Aero-engine Min-Max switching control method based on anti-saturation compensation

Abstract

The invention discloses an aero-engine Min-Max switching control method based on anti-saturation compensation in order to solve the problems that in the transition state process of an existing aero-engine Min-Max switching control strategy, due to integral saturation, system overshoot is too large, oscillation is violent, and adjusting time is too long. Based on the difference value between the output of the steady-state controller and the output of the Min-Max selection module, the internal parameters of the steady-state controller are corrected in real time by introducing the anti-saturation compensation loop, and the integral saturation phenomenon is effectively inhibited. Compared with an existing Min-Max switching control strategy, the method can remarkably improve the transition state performance of the engine on the premise of ensuring that the steady state performance is not affected, and has the advantages of being small in system overshoot, small in output oscillation, short in adjusting time and the like. The system is simple in structure, only an external compensation loop is added on the basis of a traditional Min-Max switching framework, an original control structure is not changed, the system is easy to integrate and implement in an existing aero-engine control system, and the engineering applicability is high.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine control technology, specifically relating to an aero-engine Min-Max switching control method based on anti-saturation compensation. Background Technology

[0002] Aero-engines are complex aero-thermo-mechanical systems that need to respond safely, quickly, and smoothly to pilot thrust commands under various operating conditions. However, due to physical constraints such as engine speed, temperature, acceleration, and pressure ratio, the control system must dynamically balance optimal performance with safety protection. Currently, aero-engine control systems commonly employ methods such as... Figure 1 The diagram illustrates a Min-Max switching control framework. Under this framework, the basic fuel command generated by the steady-state controller (typically a PI controller) does not directly affect the engine. Instead, it is first calculated by taking the minimum (Min) value from the output of the acceleration planner, and then by taking the maximum (Max) value from the output of the deceleration planner. The final result is transmitted to the engine as the fuel flow setpoint. The core idea of ​​this structure is to select the most "tightly constrained" control command among multiple control channels, ensuring that the engine meets thrust requirements while adhering to preset safety boundaries under any operating condition, thus avoiding dangerous conditions such as overheating, overspeeding, and surge.

[0003] However, under the aforementioned control framework, the engine control system is prone to integral saturation during the transient process. The acceleration process is used as an example for illustration. During acceleration, when the steady-state controller output exceeds the planned acceleration output, the min operation selects the smaller planned acceleration output as the final fuel flow command, causing the steady-state controller output to deviate from the actual engine input. At this point, the steady-state controller's feedback loop effectively fails, but due to the persistent tracking error, the integral term in the steady-state controller accumulates, resulting in integral saturation. This causes the steady-state controller's internal state to be incorrectly updated, and its output value continues to increase. Consequently, it takes a long time for the steady-state controller output to fall below the planned acceleration output, thus achieving a switch from the planned acceleration to the steady-state controller's control authority. The direct consequence of this phenomenon is that the planned acceleration dominates the acceleration process for an extended period, leading to increased system overshoot, exacerbated oscillations, prolonged settling time, and even dangerous conditions such as overheating, overspeeding, and surge. This degrades the transient control quality and is detrimental to the safe and stable operation of the engine. Summary of the Invention

[0004] Purpose of the invention: To address the problems of excessive system overshoot, severe oscillation, and excessively long settling time caused by integral saturation during controller switching in existing Min-Max switching control strategies for aero-engines, this invention proposes a Min-Max switching control method for aero-engines based on anti-saturation compensation (specific structure as follows). Figure 2(As shown). This invention, based on the difference between the steady-state controller output and the Min-Max module output, dynamically adjusts the internal parameters of the steady-state controller by introducing an anti-saturation compensation mechanism, effectively suppressing integral saturation. Compared with traditional Min-Max switching control, this method can significantly improve the engine's transient performance while ensuring that steady-state performance is not affected, and has advantages such as small system overshoot, small output oscillation, and short settling time.

[0005] Technical solution: To achieve the above objectives, the technical solution adopted by this invention is as follows: A Min-Max switching control method for aero-engines based on anti-saturation compensation is characterized by introducing an anti-saturation compensation mechanism on the basis of the traditional Min-Max control framework. This mechanism eliminates the adverse effects of integral saturation on the engine's transient performance by dynamically adjusting the steady-state controller parameters. The method achieves anti-saturation compensation through the following steps: S1. Difference Calculation: Real-time acquisition of steady-state controller output value Fuel flow setpoint output by the Min-Max selection module The difference between the two was calculated. ; S2. Correction amount generation: Take the absolute value of the difference mentioned in S1 and multiply it by the anti-saturation gain to obtain the steady-state controller parameter correction amount; S3. Control parameter correction: Feedback the correction amount mentioned in S2 to the steady-state controller for real-time correction of the steady-state controller parameters; S4. Controller Output Update: The steady-state controller uses the corrected control parameters to calculate the controller output value. .

[0006] Preferably, the "steady-state controller" is a PI controller.

[0007] Preferably, the "Min-Max selection module" mentioned in step S1 includes a Min selector and a Max selector, and its logic is as follows: the first input terminal of the Min selector is connected to the output of the steady-state controller. The second input terminal is connected to the output of the acceleration planner, and the smaller of the two is used as the output of the Min selector; the first input terminal of the Max selector is connected to the output of the Min selector, and the second input terminal is connected to the output of the deceleration planner, and the larger of the two is used as the output of the Max selector, ultimately obtaining the fuel flow setpoint. .

[0008] Preferably, the "anti-saturation gain" mentioned in step S2 includes the proportional element's anti-saturation gain. Anti-saturation gain of the integral element Both were obtained through trial and error.

[0009] Preferably, the "steady-state controller parameter correction amount" mentioned in step S2 includes the proportional coefficient correction amount. and integral coefficient correction amount Both are calculated using the following formulas: , .

[0010] Preferably, the "corrected control parameters" mentioned in step S4 include a proportional coefficient. and integral coefficient Both are calculated using the following formulas: , , in, and These are the initial proportional coefficient and initial integral coefficient of the steady-state controller, respectively, which are the original controller parameters without the introduction of anti-saturation compensation.

[0011] Preferably, the input to the steady-state controller is the high-voltage rotor speed tracking error. It is calculated using the following formula: , in, and These represent the expected and actual values ​​of the high-pressure rotor speed, respectively.

[0012] Preferably, the "steady-state controller output value" mentioned in step S4 The calculation formula is as follows: .

[0013] Preferably, the "acceleration / deceleration plan" is optimized based on the actual control requirements during the acceleration and deceleration process of the aero-engine at different flight altitudes and Mach numbers.

[0014] Preferably, only when the fuel flow rate is given. With steady-state controller output When the values ​​are not equal, anti-saturation compensation will intervene to avoid integral saturation by dynamically adjusting the control parameters; when the values ​​are equal, the control parameter correction is zero, anti-saturation compensation will be deactivated, and the engine control system will maintain its nominal performance.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1) This invention introduces an anti-saturation compensation mechanism in the Min-Max switching loop, which effectively suppresses integral saturation by real-time correction of the internal parameters of the steady-state controller, avoids erroneous updates of the controller state, and enables the steady-state controller output to fall back quickly, significantly shortening the control switching time and improving the transient control quality of the aero-engine. It has advantages such as small system overshoot, small output oscillation, and short adjustment time.

[0016] 2) The anti-saturation compensation loop introduced in this invention only works in the transition state when the control quantity becomes saturated, and automatically fails in the steady state. This ensures that the original nominal steady-state performance of the system is not affected, and also achieves parameter decoupling between the dynamic process and the steady-state performance, which is convenient for independent optimization.

[0017] 3) The present invention can intelligently select the optimal compensation intensity from the preset anti-saturation gain group according to different flight conditions, thereby enhancing the adaptability and control effect of the system at different operating points.

[0018] 4) The present invention has a simple structure, adding only an external compensation loop to the traditional Min-Max switching framework without changing the original control structure. It is easy to integrate and implement in existing aero-engine control systems and has strong engineering applicability. Attached Figure Description

[0019] Figure 1 This is a block diagram of the Min-Max switching control structure for a traditional aero-engine.

[0020] Figure 2 This is a block diagram of the Min-Max switching control structure for aero-engines based on anti-saturation compensation proposed in this invention.

[0021] Figure 3 This is a comparison chart of the high-voltage rotor speed curves in an embodiment of the present invention.

[0022] Figure 4 This is a comparison chart of the output curves of the steady-state controller in an embodiment of the present invention.

[0023] Figure 5 This is a comparison chart of the output curves (fuel flow rate setpoint) of the Min-Max selection module in an embodiment of the present invention.

[0024] Figure 6 This is a comparison chart of actual fuel flow curves in an embodiment of the present invention.

[0025] Figure 7 This is a comparison diagram of control switching signals in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention provides a Min-Max switching control method for aero-engines based on anti-saturation compensation, the specific implementation method of which includes the following steps: S1. Difference Calculation: Real-time acquisition of steady-state controller output value Fuel flow setpoint output by the Min-Max selection module The difference between the two was calculated. ; S2. Correction amount generation: Take the absolute value of the difference mentioned in S1 and multiply it by the anti-saturation gain to obtain the steady-state controller parameter correction amount; S3. Control parameter correction: Feedback the correction amount mentioned in S2 to the steady-state controller for real-time correction of the steady-state controller parameters; S4. Controller Output Update: The steady-state controller uses the corrected control parameters to calculate the controller output value. .

[0028] Preferably, the "steady-state controller" is a PI controller.

[0029] Preferably, the "Min-Max selection module" mentioned in step S1 includes a Min selector and a Max selector, and its logic is as follows: the first input terminal of the Min selector is connected to the output of the steady-state controller. The second input terminal is connected to the output of the acceleration planner, and the smaller of the two is used as the output of the Min selector; the first input terminal of the Max selector is connected to the output of the Min selector, and the second input terminal is connected to the output of the deceleration planner, and the larger of the two is used as the output of the Max selector, ultimately obtaining the fuel flow setpoint. .

[0030] Preferably, the "anti-saturation gain" mentioned in step S2 includes the proportional element's anti-saturation gain. Anti-saturation gain of the integral element Both were obtained through trial and error.

[0031] Preferably, the "steady-state controller parameter correction amount" mentioned in step S2 includes the proportional coefficient correction amount. and integral coefficient correction amount Both are calculated using the following formulas: , .

[0032] Preferably, the "corrected control parameters" mentioned in step S4 include a proportional coefficient. and integral coefficient Both are calculated using the following formulas: , , in, and These are the initial proportional coefficient and initial integral coefficient of the steady-state controller, respectively, which are the original controller parameters without the introduction of anti-saturation compensation.

[0033] Preferably, the input to the steady-state controller is the high-voltage rotor speed tracking error. It is calculated using the following formula: , in, and These represent the expected and actual values ​​of the high-pressure rotor speed, respectively.

[0034] Preferably, the "steady-state controller output value" mentioned in step S4 The calculation formula is as follows: .

[0035] Preferably, the "acceleration / deceleration plan" is optimized based on the actual control requirements during the acceleration and deceleration process of the aero-engine at different flight altitudes and Mach numbers.

[0036] Preferably, only when the fuel flow rate is given. With steady-state controller output When the values ​​are not equal, anti-saturation compensation will intervene to avoid integral saturation by dynamically adjusting the control parameters; when the values ​​are equal, the control parameter correction is zero, anti-saturation compensation will be deactivated, and the engine control system will maintain its nominal performance.

[0037] In this embodiment, using a nonlinear component-level model of a hybrid exhaust twin-shaft turbofan engine in the MATLAB / Simulink simulation environment, the proposed Min-Max switching control method based on anti-saturation compensation (hereinafter referred to as the M2 method) and the traditional Min-Max switching control method (hereinafter referred to as the M1 method) were compared and verified. The control input set in the simulation was the throttle lever angle from... Push to The desired control objective is to reduce the high-voltage rotor speed from Upgraded to Flight conditions are set at altitude 0 km and Mach number 0. The proportional element anti-saturation gain in the M2 method. Anti-saturation gain of the integral element The parameters were set to 0.12 and 0.2 respectively. This set of parameters was determined through model-based simulation optimization and can achieve excellent anti-saturation effect under the flight conditions.

[0038] Simulation results are as follows Figures 3 to 7 As shown. From the response curve of the high-pressure rotor speed ( Figure 3 It can be clearly seen that when the throttle lever moves from... Quickly push to During the acceleration process, when using the traditional M1 method, the high-voltage rotor speed reaches the target value. It then continued to rise to It appeared The overshoot was significant, with a settling time of 15.13 seconds. In contrast, using the M2 method of this invention resulted in a smoother speed increase to the peak value. The overshoot was only The adjustment time has been shortened to 11.25 seconds, and the transition process is smoother.

[0039] The fundamental reason for this performance improvement lies in the fact that the anti-saturation compensation mechanism effectively avoids the integral saturation phenomenon of the steady-state controller. Figure 4 The acceleration plan output signal and the steady-state controller output values ​​under two methods are shown. The curve shows the change in speed. During the initial acceleration phase with a sudden change in throttle lever angle, the integral term in the traditional M1 method continuously accumulates due to the persistent tracking error of the high-voltage rotor speed, leading to a decrease in the steady-state controller output. The price remains high. However, in the M2 method of this invention, once the steady-state controller output is detected... With the final fuel flow setpoint If a difference exists, the anti-saturation compensation loop immediately and dynamically adjusts the proportional and integral coefficients of the steady-state controller, so that... It can quickly fall back down, thus avoiding excessive saturation accumulation of the controller state.

[0040] The rapid drop in the steady-state controller output directly prompts the Min-Max selection module to switch more quickly. For example... Figure 5 As shown, at the throttle lever angle from Push to During the acceleration process, the final fuel flow rate setpoint under the M2 method of this invention It can more quickly break free from the limitations of the acceleration program and switch to a steady-state controller-driven approach. Accordingly, such as... Figure 6As shown, the dynamic performance of the actual fuel flow rate is significantly improved under the M2 method. Specifically, the peak fuel flow rate of the traditional M1 method reaches 7029 kg / h, while the peak fuel flow rate of the M2 method of this invention is 6908 kg / h, a reduction of approximately [missing information]. The adjustment time has been shortened from 15.13 seconds to 11.25 seconds, which is consistent with the adjustment time of the high-pressure rotor speed. This indicates that the fuel supply system can enter a stable state more quickly, avoiding long-term high-level fluctuations in fuel flow and effectively reducing the risk of overheating, overspeeding or surge caused by rich fuel during the transition process of the engine.

[0041] Figure 7 The switching signal directly reflects the control handover process. In the diagram, steady-state controller activation is defined as Mode 1, and acceleration plan activation is defined as Mode 2. It can be observed that in the traditional M1 method, the acceleration plan retains control for a long period, and the activation time of Mode 2 is as long as 7.73 seconds, resulting in a long transition state adjustment time and large overshoot. However, by adopting the M2 method of this invention, control can be quickly returned to the steady-state controller, and the activation time of Mode 2 is shortened to 6.02 seconds, a reduction of [missing information]. This allows for precise control of fuel flow while ensuring acceleration performance.

[0042] In summary, the simulation results in the embodiments fully verify the effectiveness of the technical solution of the present invention. By introducing an anti-saturation compensation mechanism into the traditional Min-Max control framework, the present invention can significantly improve the dynamic performance of aero-engines when the throttle lever angle changes rapidly, while maintaining the original steady-state control performance. This is manifested in small overshoot, short adjustment time, fast switching speed, and simple structure, making it easy to implement in engineering.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Min-Max switching control method for aero-engines based on anti-saturation compensation, characterized in that, Based on the traditional Min-Max control framework, an anti-saturation compensation mechanism is introduced. This mechanism eliminates the adverse effects of integral saturation on engine transient performance by dynamically adjusting the steady-state controller parameters. The method achieves anti-saturation compensation through the following steps: S1. Difference Calculation: Real-time acquisition of steady-state controller output value Fuel flow setpoint output by the Min-Max selection module The difference between the two was calculated. ; S2. Correction amount generation: Take the absolute value of the difference mentioned in S1 and multiply it by the anti-saturation gain to obtain the steady-state controller parameter correction amount; S3. Control parameter correction: Feedback the correction amount mentioned in S2 to the steady-state controller for real-time correction of the steady-state controller parameters; S4. Controller Output Update: The steady-state controller uses the corrected control parameters to calculate the controller output value. .

2. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The steady-state controller is a PI controller.

3. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The Min-Max selection module mentioned in step S1 includes a Min selector and a Max selector, and its logic is as follows: the first input terminal of the Min selector is connected to the output of the steady-state controller. The second input terminal is connected to the output of the acceleration planner, and the smaller of the two is used as the output of the Min selector; the first input terminal of the Max selector is connected to the output of the Min selector, and the second input terminal is connected to the output of the deceleration planner, and the larger of the two is used as the output of the Max selector, ultimately obtaining the fuel flow setpoint. .

4. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The anti-saturation gain mentioned in step S2 includes the proportional element anti-saturation gain. Anti-saturation gain of the integral element Both were obtained through trial and error.

5. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The steady-state controller parameter correction amount mentioned in step S2 includes the proportional coefficient correction amount. and integral coefficient correction amount Both are calculated using the following formulas: ， 。 6. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The corrected control parameters mentioned in step S4 include the proportional coefficient. and integral coefficient Both are calculated using the following formulas: ， ， in, and These are the initial proportional coefficient and initial integral coefficient of the steady-state controller, respectively, which are the original controller parameters without the introduction of anti-saturation compensation.

7. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The input to the steady-state controller is the high-voltage rotor speed tracking error. It is calculated using the following formula: , in, and These represent the expected and actual values ​​of the high-pressure rotor speed, respectively.

8. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The steady-state controller output value described in step S4 The calculation formula is as follows: 。 9. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: The acceleration / deceleration plan is optimized based on the actual control requirements during the acceleration / deceleration process of the aircraft engine at different flight altitudes and Mach numbers.

10. The Min-Max switching control method for aero-engines based on anti-saturation compensation according to claim 1, characterized in that: Only when the fuel flow rate is given With steady-state controller output When the values ​​are not equal, anti-saturation compensation will intervene to avoid integral saturation by dynamically adjusting the control parameters; when the values ​​are equal, the control parameter correction is zero, anti-saturation compensation will be deactivated, and the engine control system will maintain its nominal performance.

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