CN103543743A - Method for preventing control plane integral saturation in aircraft ground servo elasticity test - Google Patents

Abstract

The invention belongs to the field of aircraft strength tests, relates to the category of aircraft aeroelasticity tests, and in particular to an anti-integral saturation method for rudder surfaces of aircraft ground servo elasticity tests. The present invention connects a real-time simulation system between the flight control sensor and the flight control computer. The real-time simulation system includes a main control computer and a simulation computer. The high-pass filter parameter setting and compilation are completed in the main control computer and then transmitted to the simulation computer. The parameter design of the high-pass filter of the present invention is constrained by the dynamic characteristics of the control law within the elastic vibration frequency range of the aircraft, prolonging the integral saturation time of the rudder surface, effectively curbing the rapid integral saturation of the rudder surface, and minimizing the influence on the test results; The filter is placed in an external simulator without any adjustments to the hardware and software of the airborne control system, and the filter parameters can be adjusted according to the actual situation during the test, which has strong adaptability and strong practicability.

Description

A method for anti-integral saturation of rudder surface in aircraft ground servo elasticity test

technical field

The invention belongs to the field of aircraft strength tests, relates to the category of aircraft aeroelasticity tests, and in particular to an anti-integral saturation method for rudder surfaces of aircraft ground servo elasticity tests.

Background technique

Most modern digital fly-by-wire flight control systems have the functions of attitude maintenance and automatic trimming, and the realization of these control functions usually requires an integral link in the feedback loop. Due to the integral link in the feedback loop, in the ground servo elasticity test, as long as there is zero drift or static error in the feedback signal, the rudder deviation command will be saturated as time goes by, especially when the integral constant in the feedback loop is large, the rudder surface Will quickly saturate in a short period of time, making the test impossible.

At present, for the rudder surface integral saturation problem in the ground servo elastic test, the integral short-circuit method is usually used, that is, the integral link in the feedback loop is directly removed. Obviously, this will change the dynamic characteristics of the control law within the elastic vibration frequency range of the aircraft. , affecting the reliability of the test results.

Contents of the invention

The purpose of the invention is: under the premise of ensuring the minimum impact on the dynamic characteristics of the flight control law in the elastic vibration frequency range of the aircraft, solve the problem of rapid integral saturation of the rudder surface due to the presence of an integral link in the feedback loop in the aircraft ground servo elasticity test, which cannot Technical issues with normal testing.

Technical scheme of the present invention:

A real-time simulation system is connected between the flight control sensor and the flight control computer. The real-time simulation system includes the main control computer and the simulation computer. The high pass filter parameter settings are,

1) Construct a high-pass filter transfer function:

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&xi;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

In the formula: s is the Laplacian operator, ω _n is the circular frequency, ξ=0.5～1.0 is the damping ratio;

2) Given the damping ratio ξ, solve the following constrained optimization problem to get ω _n

Where i is the imaginary number symbol, ΔA is the maximum amplitude deviation allowed by the test, is the maximum phase deviation allowed by the test, ω ₁ is the lowest order natural elastic vibration circular frequency of the aircraft;

3) Substitute ω _n and ξ into the above step 1) to obtain the specific expression of the high-pass filter _HF (s);

4) Compile the high-pass filter _HF (s) in the main control computer, generate executable code and transmit it to the simulation computer;

5) The output signal of the flight control sensor passes through the high-pass filter H _F (s) in the simulation computer to eliminate zero drift or static error, and then enters the flight control computer to solve the rudder deviation command.

The advantages and positive effects that the present invention has are: in the feedback loop that has integrator, introduce high-pass filter, take the flight control law dynamic characteristic change amount in the elastic vibration frequency range of aircraft as constraint, carry out filter parameter design, in Prolonging the integral saturation time of the rudder surface can effectively curb the rapid integral saturation of the rudder surface, and at the same time minimize the influence of the introduction of the filter on the test results. Compared with the existing integral short-circuit method, it can effectively improve the reliability of the test results. In addition, since the zero drift or static error elimination of the feedback signal is realized through the digital filter placed in the real-time simulation system, there is no need to make any changes to the hardware and software of the airborne control system, and it can be used during the test according to The filter parameters are adjusted in real time according to the actual situation, and the adaptability is strong.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the present invention.

Detailed ways

The present invention will be described in detail with reference to the accompanying drawings.

1. A real-time simulation system is connected between the flight control sensor and the flight control computer of the aircraft. The real-time simulation system includes the main control computer and the simulation computer;

2. Complete the high-pass filter parameter setting in the main control computer, as follows:

1) According to the amplitude-phase-frequency characteristics of a typical second-order system in control theory, the form of the high-pass filter transfer function is constructed as follows:

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&xi;</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

In the formula: s is the Laplacian operator, ω _n is the circular frequency, ξ=0.5～1.0 is the damping ratio;

2) Select the damping ratio ξ (the value of ξ is proportional to the frequency of the lowest-order elastic vibration mode of the aircraft), and the amplitude of the high-pass filter _HF (s) at 0.01 times the lowest-order elastic mode frequency of the aircraft is the smallest As the objective function, construct the following constrained optimization problem

为试验允许的最大相位偏差，ω₁为飞机的最低阶固有弹性振动圆频率。Where i is the imaginary number symbol, ΔA is the maximum amplitude deviation allowed by the test,

is the maximum phase deviation allowed by the test, and ω ₁ is the lowest order natural elastic vibration circular frequency of the aircraft.

3) Solve the constrained optimization problem constructed in the above step 2) to obtain ω _n

4) Substitute ω _n and ξ into the above step 1) to obtain the specific expression of the high-pass filter _HF (s);

3. Compile the high-pass filter _HF (s) in the main control computer, generate executable code and transmit it to the simulation computer;

4. The output signal of the flight control sensor passes through the high-pass filter _HF (s) in the simulation computer to eliminate zero drift and static error, and then enters the flight control computer to solve the rudder deviation command, so as to avoid the rapid integral saturation of the rudder surface.

Example

1. A real-time simulation system is connected between the flight control sensor and the flight control computer. The real-time simulation system includes the main control computer and the simulation computer

2. Complete the high-pass filter parameter setting in the main control computer, as follows

1) Construct the high-pass filter transfer function as follows:

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&xi;</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

2) Select ξ=0.707 to solve the following constrained optimization problem

ω₁＝11.6rad/sWhere ΔA = 0.18dB,

ω ₁ =11.6rad/s

Obtain ω _n =0.4293, the concrete expression of high-pass filter H _F (s):

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.6066</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.184</span>}}$

3. The high-pass filter _HF (s) model established in the main control computer is compiled and downloaded to the simulation computer;

4. The tilt angle feedback signal is high-pass filtered through the simulator first, and then sent to the flight control computer for control law calculation and output rudder deviation command;

地面伺服弹性试验中倾斜角存在2.3度的静差，若对倾斜角信号不进行高通滤波，则舵面将在控制系统接通14秒后达到满偏角20度，但倾斜角信号经过上述高通滤波处理后，系统接通30m分钟之后，舵面仍保持在中立位置。5. When the autopilot is turned on, there is an integral link in the tilt angle feedback loop

In the ground servo elasticity test, there is a static difference of 2.3 degrees in the tilt angle. If the high-pass filter is not performed on the tilt angle signal, the rudder surface will reach the full tilt angle of 20 degrees after the control system is turned on for 14 seconds, but the tilt angle signal passes through the above-mentioned high-pass filter. After the filter processing, the rudder surface remains in the neutral position 30m after the system is switched on.

Claims (1)

1. a kind of anti-integral saturation method of aircraft ground servo elastic test rudder surface, it is characterized in that, string into real-time simulation system between flight control sensor and flight control computer, real-time simulation system comprises main control computer and simulation computer, in main control The high-pass filter parameter setting and compilation are completed in the computer and then transmitted to the simulation computer; the high-pass filter parameter setting in the main control computer is, 1) Construct a high-pass filter transfer function: ${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&xi;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$ In the formula: s is the Laplacian operator, ω _n is the circular frequency, ξ=0.5～1.0 is the damping ratio; 2) Given the damping ratio ξ, solve the following constrained optimization problem to get ω _n

Where i is the imaginary number symbol, ΔA is the maximum amplitude deviation allowed by the test,

is the maximum phase deviation allowed by the test, ω ₁ is the lowest order natural elastic vibration circular frequency of the aircraft; 3) Substitute ω _n and ξ into the above step 1) to obtain the specific expression of the high-pass filter _HF (s); 4) Compile the high-pass filter _HF (s) in the main control computer, generate executable code and transmit it to the simulation computer; 5) The output signal of the flight control sensor passes through the high-pass filter H _F (s) in the simulation computer to eliminate zero drift or static error, and then enters the flight control computer to solve the rudder deviation command.

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