Aero-engine high-speed slow-speed control method based on sliding mode variable-damping guide vane regulation

Abstract

This invention discloses a high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment. According to the engine's high-speed idle acceleration plan, a high-pressure compressor adjustable stator blade angle adjustment plan is determined. Based on this plan, an electro-hydraulic actuator and an aero-engine simulation model are established to control the high-pressure compressor adjustable stator blade angle. A position controller is used to control the electro-hydraulic actuator to eliminate the adjustment error of the high-pressure compressor adjustable stator blade angle, achieving the required high-pressure compressor adjustable stator blade angle for the engine's high-speed idle acceleration plan. This invention effectively improves the thrust response speed of aero-engines, provides an important reference for engine emergency response control, and is of great significance for improving the control performance of aircraft in emergency situations.

Description

Technical Field

[0001] This invention belongs to the field of aero-engines and relates to a high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment. Background Technology

[0002] When an aircraft is in an emergency, such as when a component is damaged, control actuators may fail or aerodynamic characteristics may change, adversely affecting the aircraft's stability and controllability. Engine emergency response control can improve aircraft stability and controllability to some extent in such situations. However, the stable operation of aero engines is subject to numerous boundary conditions, making engine emergency response control a highly complex problem.

[0003] Currently, rapid response control for aero-engines mainly employs methods such as control gain adjustment and acceleration plan adjustment. Control gain adjustment is only suitable for situations with small changes in engine thrust; while acceleration plan adjustment improves engine acceleration capability by adjusting the engine's acceleration plan curve, but the acceleration plan is limited by surge margin, resulting in limited performance improvement. Some research has proposed dynamic stabilization methods to find the optimal acceleration plan without sacrificing safety, but this requires large-scale modifications to the existing controller and incurs enormous computational costs. High-speed idle control is an emergency control strategy that can improve the thrust response speed of high-bypass turbofan engines by adjusting fuel supply and the adjustable guide vane angle of the high-pressure compressor without significant modifications to the existing controller, and without causing a substantial decrease in safety margin. Existing high-speed idle research has only verified the effectiveness of adjusting the guide vane angle in improving engine response speed, with insufficient consideration given to specific guide vane angle adjustment methods and hydraulic leakage issues. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art and provide a high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment, which solves the problem of insufficient consideration of guide vane angle adjustment method and hydraulic leakage problem in the emergency response control process of aero-engines.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment includes:

[0007] Based on the engine high-speed idle acceleration plan, determine the high-pressure compressor adjustable stator blade angle adjustment plan;

[0008] Based on the adjustable stator blade angle adjustment plan of the high-pressure compressor, an electro-hydraulic actuator and aero-engine simulation model are established to control the adjustable stator blade angle of the high-pressure compressor.

[0009] The position controller controls the electro-hydraulic actuator to eliminate the adjustment error of the adjustable stator blade angle of the high-pressure compressor, so as to achieve the high-pressure compressor adjustable stator blade angle required for the engine's high-speed idle acceleration plan.

[0010] Furthermore, the angle required for the adjustable stator blade angle adjustment plan of the high-pressure compressor is:

[0011] α=f(n,T)

[0012] Where α is the adjustable stator blade angle of the high-pressure compressor, n is the engine high-pressure compressor speed, T is the high-pressure turbine inlet temperature, and f is the adjustment law of the non-nominal adjustable stator blade angle of the high-pressure compressor under the high-speed idle acceleration plan.

[0013] Furthermore, the electro-hydraulic actuator simulation model is an electro-hydraulic actuator model of the actuator established using AMESim software, and the aero-engine simulation model is a high bypass ratio turbofan engine model established using GasTurb software.

[0014] Furthermore, the electro-hydraulic actuator model includes a permanent magnet synchronous motor, a plunger pump, and a hydraulic cylinder.

[0015] Furthermore, the speed and current of the permanent magnet synchronous motor are expressed by the following formula:

[0016]

[0017] Among them, i q Let L be the q-axis current, L be the stator inductance, R be the stator resistance, and u be the q-axis current. q Let k be the q-axis voltage. e Here, ω is the back EMF coefficient, k is the motor speed, and k is the motor speed. t T is the torque coefficient. L For load, B m is the damping coefficient, s is the Laplace operator, and J is the moment of inertia.

[0018] Furthermore, the load on the plunger pump is:

[0019]

[0020] Among them, T L For the load of the plunger pump, D p Δp represents the displacement of the plunger pump, and Δp represents the pressure difference.

[0021] Furthermore, the hydraulic pressure difference between the two ends of the hydraulic cylinder is expressed by a first-order dynamic equation as follows:

[0022]

[0023] Where Δp is the hydraulic pressure difference between the two ends of the hydraulic cylinder. Let A be the first derivative of the hydraulic differential, A be the effective area of ​​the hydraulic cylinder actuator, and β be the first derivative of the hydraulic differential. e C is the elastic modulus of hydraulic oil. in C is the internal leakage coefficient. out V is the external leakage coefficient, and V is the hydraulic cylinder capacity. The first-order derivative is the position of the piston movement in the actuator cylinder.

[0024] Furthermore, the piston movement position of the actuator cylinder is expressed by a second-order dynamic equation as follows:

[0025]

[0026] in, Let be the second-order derivative of the piston movement position of the actuator cylinder, m be the inertial mass of the piston and load, Δp be the pressure difference between the two sides of the hydraulic cylinder, B be the load damping coefficient, and F be the external force on the load end.

[0027] Furthermore, the control law of the position controller based on the sliding mode control method is as follows:

[0028]

[0029] in, e represents the systematic error.

[0030] Furthermore, the control law of the position controller based on the variable damping sliding mode control method is as follows:

[0031]

[0032] Where k is the damping coefficient (k>0).

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention provides a high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment. According to the engine's high-speed idle acceleration plan, a high-pressure compressor adjustable stator blade angle adjustment plan is determined. An electro-hydraulic actuator and aero-engine simulation model are established. The angle of the high-pressure compressor adjustable stator blades is controlled by a position controller. The electro-hydraulic actuator eliminates the adjustment error of the high-pressure compressor adjustable stator blade angle, achieving the required high-pressure compressor adjustable stator blade angle for the engine's high-speed idle acceleration plan. This invention establishes a joint simulation model of the electro-hydraulic actuator and the engine, and designs an engine guide vane adjustment control method based on variable damping sliding mode position control. This effectively improves the thrust response speed of aero-engines, provides an important reference for engine emergency response control, and is of great significance for improving the control performance of aircraft in emergency situations.

[0035] Furthermore, the designed variable damping sliding mode position controller can achieve better high-pressure compressor adjustable stator blade angle adjustment performance than traditional sliding mode control and PID control, realizing lower overshoot and faster adjustment speed. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of the high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to the present invention.

[0038] Figure 2 This is a structural diagram of the EHA in Embodiment 1 of the present invention.

[0039] Figure 3 This is a schematic diagram of the EHA control principle in Embodiment 1 of the present invention.

[0040] Figure 4 This is a diagram illustrating the connection method between EHA and VSV in Embodiment 1 of the present invention.

[0041] Figure 5 This is a step response diagram of variable damping sliding mode control according to Embodiment 1 of the present invention.

[0042] Figure 6 This is a diagram illustrating the high-speed slow-speed train control effect of Embodiment 1 of the present invention. Detailed Implementation

[0043] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of this application, including various details to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0044] Obviously, the described embodiments are only some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0045] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0046] The present invention will now be described in further detail:

[0047] See Figure 1 This invention provides a high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment, comprising the following steps:

[0048] Step 1: Determine the adjustable stator blade (VSV) angle adjustment plan for the high-pressure compressor.

[0049] This step determines the non-nominal VSV angle adjustment plan based on the engine's high-speed idle acceleration plan. Under the given high-speed idle acceleration plan, the required angle for the VSV adjustment plan during acceleration is determined as follows:

[0050] α=f(n,T)

[0051] Where α is the VSV angle, n is the engine high-pressure compressor speed, T is the high-pressure turbine inlet temperature, and f is the non-nominal VSV angle adjustment law under the high-speed idle strategy.

[0052] Step 2: Establish simulation models of the electro-hydrostatic actuator (EHA) and the aero-engine.

[0053] Based on the VSV angle adjustment plan under the high-speed idle acceleration plan obtained in Step 1, an electro-hydraulic actuator (EHA) and an aero-engine simulation model are established, and the EHA is used to control the VSV angle. The VSV angle adjustment error corresponds to a certain EHA actuator rod position error. By controlling the EHA motor speed to adjust the pressure difference on both sides of the actuator cylinder, the actuator rod position error is eliminated, and finally the VSV angle α required by the acceleration plan is achieved. Therefore, it is necessary to model the actuator EHA and the engine. A high-bypass turbofan engine model is established using GasTurb software, and an actuator EHA model is established using AMESim software. The main components of the EHA include a permanent magnet synchronous motor, a piston pump, and a hydraulic cylinder.

[0054] Determine the speed ω and current i of the EHA permanent magnet synchronous motor. q It can be expressed by the following formula:

[0055]

[0056] Among them, i qLet L be the q-axis current, L be the stator inductance, R be the stator resistance, and u be the q-axis current. q Let k be the q-axis voltage. e Here, ω is the back EMF coefficient, k is the motor speed, and k is the motor speed. t T is the torque coefficient. L For load, B m is the damping coefficient, s is the Laplace operator, and J is the moment of inertia.

[0057] Determine the load T of the EHA plunger pump L , represented as:

[0058]

[0059] Among them, D p Δp represents the displacement of the plunger pump, in ml / r, and Δp represents the pressure difference, in bar.

[0060] The hydraulic pressure difference Δp between the two ends of the hydraulic cylinder is determined and expressed by a first-order dynamic equation as follows:

[0061]

[0062] in, Let A be the first derivative of the hydraulic differential, A be the effective area of ​​the hydraulic cylinder actuator, and β be the first derivative of the hydraulic differential. e C is the elastic modulus of hydraulic oil. in C is the internal leakage coefficient. out V is the external leakage coefficient, and V is the hydraulic cylinder capacity. The first-order derivative is the position of the piston movement in the actuator cylinder.

[0063] Determine the piston movement position x of the actuator. Due to leakage, the motor needs to maintain an additional speed to replenish the hydraulic oil so that the actuator rod reaches the desired position. The actuator motion equation can be expressed using the second-order dynamic equation:

[0064]

[0065] in, Let be the second-order derivative of the piston movement position of the actuator cylinder, m be the inertial mass of the piston and load, Δp be the pressure difference between the two sides of the hydraulic cylinder, B be the load damping coefficient, and F be the external force on the load end.

[0066] Step 3: Design a position controller based on sliding mode control.

[0067] Based on the position error of the EHA actuator, the error is eliminated through feedback control. The position controller adopts a sliding mode control method, and the state variables of the control system are taken as X = [x1 x2 x3]. T Where, x1 = x,

[0068] We can obtain,

[0069]

[0070] Differentiating both sides of the above equation, we get...

[0071]

[0072] This can be obtained by substituting the simulation model of the electro-hydraulic actuator.

[0073]

[0074] The input signal of the position controller is x d Then the first, second, and third derivatives of the error are:

[0075]

[0076] Pick The sliding surface is switched using the exponential reaching law and the SAT function:

[0077]

[0078] Constructing Lyapunov functions but The conditions for achieving the observability of Lyapunov functions must be met.

[0079] Bundle Substitution The control law can be derived as follows:

[0080]

[0081] in,

[0082] Step 4: Increase the anti-shake damping coefficient of the controller.

[0083] To address the issue of large overshoot or even oscillation in the step response of the sliding mode controller designed in step three, a damping coefficient is introduced to adjust c2, i.e., the value of c2 changes in real time according to the system error e. (The value is then set to...) Then you can get k is the damping coefficient (k>0), used to adjust... The magnitude of the influence of e. Substituting this into the original control law, we obtain the new control law:

[0084]

[0085] The present invention will now be described in detail with reference to specific embodiments:

[0086] Example 1:

[0087] Step 1: Determine the adjustable stator blade (VSV) angle adjustment plan for the high-pressure compressor.

[0088] This step requires determining the non-nominal guide vane angle based on the engine's high-speed idle acceleration plan. The high-pressure compressor guide vane angle is adjusted using the idle acceleration plan, shifting the state point to a point with lower efficiency on the high-pressure compressor characteristic diagram. With flight conditions set as ALT = 11 km and Ma = 0.8, and the high-pressure compressor guide vane angle α = 5° determined based on the given idle high-speed acceleration plan, the desired fan speed increase is from 4000 r / min to 5000 r / min at 3 seconds. Where:

[0089] α=f(n,T)

[0090] Where α is the VSV angle, n is the engine high-pressure compressor speed, T is the high-pressure turbine inlet temperature, and f is the non-nominal VSV angle adjustment law under the high-speed idle strategy.

[0091] Step 2: Establish the EHA and aero-engine simulation model.

[0092] Based on the acceleration plan of the high-speed idler, after obtaining the VSV angle control plan, the controller obtains the error signal, and then controls the EHA to eliminate the position error, finally achieving the VSV angle α required by the acceleration plan. The actuator EHA is modeled, with the permanent magnet synchronous motor, piston pump, and hydraulic cylinder as the main components, such as... Figure 2 As shown.

[0093] A high-bypass turbofan engine model based on GasTurb was used, and an EHA model for controlling the VSV angle was built using AMESim software. The connection method between EHA and VSV is as follows. Figure 4 As shown, the EHA control principle is as follows: Figure 3 As shown in Table 1, the main parameters of EHA are as follows.

[0094] Table 1 EHA System Parameters

[0095]

[0096]

[0097] In Table 1, R is the stator resistance of the PMSM, L is the stator inductance of the PMSM, is the back EMF coefficient of the PMSM, is the torque coefficient of the PMSM, is the displacement of the piston pump, is the internal leakage coefficient of the hydraulic cylinder, is the external leakage coefficient of the hydraulic cylinder, A is the effective internal area of ​​the hydraulic cylinder, V is the effective internal volume of the hydraulic cylinder, and β e Let B be the elastic modulus of the hydraulic oil, B be the load damping coefficient, and m be the inertial mass of the piston and load.

[0098] Determine the speed ω and current i of the permanent magnet synchronous motor. q It can be expressed by the following formula:

[0099]

[0100] Among them, i q This represents the q-axis current, where L is the stator inductance, R is the stator resistance, and u... q Let k be the q-axis voltage. e Here, ω is the back EMF coefficient, k is the motor speed, and k is the motor speed. t T is the torque coefficient. L For load, B m is the damping coefficient, s is the Laplace operator, and J is the moment of inertia.

[0101] Determine the load T of the plunger pump L , represented as:

[0102]

[0103] Among them, D p Δp represents the displacement of the plunger pump, in ml / r, and Δp represents the pressure difference, in bar.

[0104] The hydraulic pressure difference Δp between the two ends of the hydraulic cylinder is determined and expressed by a first-order dynamic equation as follows:

[0105]

[0106] in, Let A be the first derivative of the hydraulic differential, A be the effective area of ​​the hydraulic cylinder actuator, and β be the first derivative of the hydraulic differential. e C is the elastic modulus of hydraulic oil. in C is the internal leakage coefficient. out V is the external leakage coefficient, and V is the hydraulic cylinder capacity. The first-order derivative is the position of the piston movement in the actuator cylinder.

[0107] Determine the piston movement position x of the actuator. Due to leakage, the motor needs to maintain an additional speed to replenish the hydraulic oil so that the actuator rod reaches the desired position. The actuator motion equation can be expressed using the second-order dynamic equation:

[0108]

[0109] in, Let be the second-order derivative of the piston movement position of the actuator cylinder, m be the inertial mass of the piston and load, Δp be the pressure difference between the two sides of the hydraulic cylinder, B be the load damping coefficient, and F be the external force on the load end.

[0110] Step 3: Design a position controller based on sliding mode control.

[0111] Based on sensor feedback and input signal position x d The error is obtained and then eliminated using a position controller. The position controller employs a sliding mode control method, with the control system state variables defined as X = [x1 x2 x3]. T Where, x1 = x,

[0112] We can obtain,

[0113]

[0114] Differentiating both sides of the above equation, we get...

[0115]

[0116] This can be obtained by substituting the simulation model of the electro-hydraulic actuator.

[0117]

[0118] The input signal of the position controller is x d Then the first, second, and third derivatives of the error are:

[0119]

[0120] Pick The sliding surface is switched using the exponential reaching law and the SAT function:

[0121]

[0122] Constructing Lyapunov functions but The conditions for achieving the observability of Lyapunov functions must be met.

[0123] Bundle Substitution The control law can be derived as follows:

[0124]

[0125] in,

[0126] Step 4: Design a variable damping sliding mode position controller.

[0127] A damping coefficient is introduced for c2, and the value of c2 changes in real time according to the system error e. Let... Then you can get k is the damping coefficient (k>0), used to adjust... The magnitude of the influence of e. Substituting this into the original control law, we obtain the new control law:

[0128]

[0129] For parameters such as c1, c2, c3, and ε, a genetic algorithm is used for optimization. Initially, 100 40-bit binary individuals are randomly generated and simulated under 10Hz and 1Hz sine and step instructions respectively. The 50 individuals with the highest fitness are selected for cross-evolution to generate 100 new individuals, and the simulation continues for the next round. The result obtained after multiple iterations is the final result. Figure 5 As shown.

[0130] Simulation results are as follows Figure 6 As shown, under the high-speed idle control strategy, the high-pressure rotor speed increases by 2.55% and the fuel flow increases by 0.4% in the idle state, while the thrust remains almost unchanged, increasing by only 0.02%. During acceleration, the high-speed idle control strategy reduces the low-pressure rotor rise time by 0.41 seconds, slightly decreases the engine stability margin from 16.5% to 14%, increases the fuel flow consumption, increases the high-pressure rotor overshoot from 13.1% to 49.2%, and increases the maximum exhaust temperature by 50K.

[0131] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment, characterized in that, include: Based on the engine high-speed idle acceleration plan, determine the high-pressure compressor adjustable stator blade angle adjustment plan; Based on the adjustable stator blade angle adjustment plan of the high-pressure compressor, an electro-hydraulic actuator and aero-engine simulation model are established to control the adjustable stator blade angle of the high-pressure compressor. The position controller controls the electro-hydraulic actuator to eliminate the adjustment error of the adjustable stator blade angle of the high-pressure compressor, so as to achieve the high-pressure compressor adjustable stator blade angle required for the engine's high-speed idle acceleration plan. The angle required for the adjustable stator blade angle adjustment plan of the high-pressure compressor is: Where α is the adjustable stator blade angle of the high-pressure compressor. This refers to the speed of the engine's high-pressure compressor. is the high-pressure turbine inlet temperature, and f is the adjustment law of the adjustable stator blade angle of the non-nominal high-pressure compressor under the high-speed idle acceleration plan; The electro-hydraulic actuator simulation model is an electro-hydraulic actuator model of the actuator established using AMESim software, and the aero-engine simulation model is a high bypass ratio turbofan engine model established using GasTurb software.

2. The high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to claim 1, characterized in that, The electro-hydraulic actuator model includes a permanent magnet synchronous motor, a plunger pump, and a hydraulic cylinder.

3. The high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to claim 2, characterized in that, The speed and current of the permanent magnet synchronous motor are expressed by the following formula: in, Let L be the q-axis current, L be the stator inductance, and R be the stator resistance. This is the q-axis voltage. The back electromotive force coefficient, This refers to the motor speed. The torque coefficient, For load, Let be the damping coefficient, and s be the Laplace operator. Let be the moment of inertia.

4. The high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to claim 2, characterized in that, The load on the plunger pump is: in, For the load of the plunger pump, This refers to the displacement of the plunger pump. This is the pressure difference.

5. The high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to claim 2, characterized in that, The hydraulic pressure difference between the two ends of the hydraulic cylinder can be expressed by a first-order dynamic equation as follows: Where Δp is the hydraulic pressure difference between the two ends of the hydraulic cylinder. Let A be the first-order derivative of the hydraulic differential, and A be the effective area of ​​the hydraulic cylinder actuator. The elastic modulus of hydraulic oil. The internal leakage coefficient is... V is the external leakage coefficient, and V is the hydraulic cylinder capacity. The first-order derivative is the position of the piston movement in the actuator cylinder.

6. The high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to claim 5, characterized in that, The piston movement position of the actuator cylinder is expressed by a second-order dynamic equation as follows: in, Let be the second derivative of the piston's movement position in the actuator cylinder, and m be the inertial mass of the piston and load. Let B be the pressure difference across the hydraulic cylinder, B be the load damping coefficient, and F be the external force applied to the load end.

7. The high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to claim 1, characterized in that, The control law of the position controller based on the sliding mode control method is: in, , , where e is the systematic error.

8. The high-speed idle control method for aero-engines based on sliding mode variable damping guide vane adjustment according to claim 1, characterized in that, The control law of the position controller based on the variable damping sliding mode control method is: Where k is the damping coefficient, k>0.

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