CN110879618B - A three-closed-loop stable tracking method for multi-disturbance observers based on acceleration and position disturbance information - Google Patents

Abstract

The invention discloses a three-closed-loop stable tracking method of a multi-disturbance observer based on acceleration and position disturbance information, which mainly solves the problem of medium-frequency and low-frequency external disturbances in the stability control platform, thereby affecting the stability and tracking accuracy of the platform. The invention adds an acceleration disturbance observer and a position disturbance observer on the basis of the traditional three-closed-loop system, thereby effectively improving the disturbance suppression capability of the system at medium and low frequencies. At the same time, the invention provides the design scheme of the acceleration disturbance compensator and the position disturbance compensator, which can improve the anti-interference ability of the stable control platform on the basis of ensuring the stability of the system. This disturbance observation method does not require additional sensors, does not increase the system cost, and performs feedforward compensation on the observed disturbance, which is easy to implement in engineering.

Description

A triple-closed-loop stabilization tracking method for multi-disturbance observers based on acceleration and position disturbance information

technical field

The invention belongs to the field of stable control platforms, and in particular relates to a multi-disturbance observer three-closed-loop stable tracking platform based on acceleration and position disturbance information, which is mainly used for enhancing the anti-interference ability of the system, and at the same time improving the robustness and tracking performance of the system. .

Background technique

If vibration reduction measures are not adopted in the stable control platform, the boresight jitter generated in the vibration environment will cause problems such as dynamic image deformation, uneven image quality, poor contrast, blurred image, and reduced sharpness. The decrease of imaging quality will lead to the decrease of the closed-loop bandwidth and tracking accuracy of the system, resulting in the loss of the tracking target. Therefore, improving the disturbance suppression ability of the system is the key to make the airborne TV image have high-quality stable tracking ability, reduce the image blur caused by flutter, and improve the imaging quality. The mechanical resonance of the system, the external vibration caused by sensor noise drift and interference torque such as friction, wind resistance, and unbalance are the main factors that limit the disturbance suppression capability of the stability control system. Disturbance sources are observed and compensated. The traditional stable control platform adopts multiple closed-loop control structures of acceleration loop, velocity loop and position loop to improve the anti-interference ability of the system. The document "MEMS InertialSensors-Based Multi-Loop Control Enhanced by Disturbance Observation and Compensation for Fast Steering Mirror System" (sensors, Vol(16), 2016) introduces the traditional disturbance observer into the acceleration loop, and further improves the disturbance of the system based on the inertial loop inhibiting ability. However, this method cannot improve the low-frequency disturbance suppression capability of the stable control platform, and even compared with the traditional multi-closed-loop structure, its low-frequency anti-disturbance capability is even worse. Therefore, in order to improve the anti-jamming capability of the system at the intermediate frequency and low frequency at the same time, it is necessary to propose a more targeted anti-jamming method.

SUMMARY OF THE INVENTION

Aiming at the problem that the stability control platform has insufficient anti-interference ability at low frequency and intermediate frequency, the present invention proposes a multi-disturbance observer three-closed-loop stable tracking method based on acceleration and position disturbance information. Based on the traditional three-closed-loop structure, this method adds an acceleration disturbance observer and a position disturbance observer, and achieves the purpose of anti-interference by performing feedforward compensation on the observed disturbance. The constraints of the disturbance compensator are given by mathematical analysis, and the experiment proves that this method can effectively improve the anti-interference ability of the system at low frequency and intermediate frequency, and enhance the robustness of the system. This method is easy to implement in engineering, does not need to add additional sensors to observe the disturbance, and is beneficial to reduce the system cost.

In order to achieve the purpose of the present invention, the present invention provides a multi-disturbance observer three-closed-loop stable tracking method based on acceleration and position disturbance information, and the method steps are as follows:

Step (1): install a microelectromechanical accelerometer and a microelectromechanical gyroscope on the X axis and the Y axis of the stable control platform to measure the angular acceleration and angular velocity of the platform in the inertial space; the CCD camera obtains the light signal received by the stable control platform, To obtain the location information of the system;

Step (2): The frequency response test is performed on the acceleration controlled object of the stable control platform through the frequency response tester, the input is the voltage value, and the output is the sampled value of the accelerometer, and the object identification of the input and output model is performed to obtain the acceleration object. Charged model

设计加速度控制器C_a(s)；通过对加速度闭环的频响测试获得速度对象的被控模型

设计速度控制器C_v(s)；再通过对加速度闭环和速度闭环的频响测试获得位置对象的被控模型

设计位置控制器C_p(s)，这样就形成了加速度、速度、位置的三闭环系统。Step (3): realize the three closed loops of the stable control platform: according to the acceleration controlled object obtained by the fitting

Design the acceleration controller C _a (s); obtain the controlled model of the velocity object through the frequency response test of the closed-loop acceleration

Design the velocity controller C _v (s); then obtain the controlled model of the position object through the frequency response test of the acceleration closed-loop and velocity closed-loop

The position controller C _p (s) is designed so that a three closed-loop system of acceleration, velocity and position is formed.

是通过频响测试得到的，是对系统实际加速度模型G_a(s)的逼近；G_a(s)的输入是速度控制器的控制量u_a，这个输出包含了外界的加速度扰动，而

的输出不包含外界扰动，通过将

和G_a(s)的输出量相减，可以观测到外界的等效加速度扰动d_a(s)；将观测到的等效加速度扰动d_a(s)输入到加速度扰动补偿器C_fa(s)中，输出量前馈到加速度控制器C_a(s)的输入量中。Step (4): Add acceleration disturbance observer and disturbance compensator: Add the mathematical model of the controlled object in the acceleration loop

It is obtained through the frequency response test and is an approximation to the actual acceleration model of the system _Ga (s); the input of _Ga (s) is the control variable u _a of the speed controller, this output contains the external acceleration disturbance, and

The output of , does not contain external disturbances, by adding

By subtracting it from the output of G _a (s), the external equivalent acceleration disturbance d _a (s) can be observed; input the observed equivalent acceleration disturbance d _a (s) to the acceleration disturbance compensator C _fa (s ), the output is fed forward to the input of the acceleration controller C _a (s).

有纯微分环节存在如下：Among them, the mathematical model of the controlled object of the acceleration ring

There are pure differential elements as follows:

Among them, Ka is the gain of the controlled object of acceleration, ω _{n is} the turning frequency of the second-order link of the denominator of the controlled object of acceleration, ζ is the parameter in the second-order link of the denominator of the controlled object of acceleration, and T _a is the denominator of the controlled object of acceleration. The parameters in the order lag link, the above four parameters can be obtained from the object identification of the acceleration controlled object.

Among them, the design form of the acceleration disturbance compensator is as follows:

Among them, T _a is the parameter in the first-order lag link of the denominator of the acceleration controlled object, and K _fa , ξ _fa , and ω _fa are all determined by the designer, and are related to the mid-band frequency (5-20 Hz) in which the disturbance is concentrated.

是通过频响测试得到的，是对系统实际加速度模型G_p(s)的逼近。G_p(s)的输入是位置控制器的控制量u_a，这个输出包含了外界的位置扰动，而

的输出不包含外界扰动，通过将

和G_p(s)的输出量相减，可以观测到外界的等效位置扰动d_p(s)；Step (5): Add a position disturbance observer: the same as adding an acceleration disturbance observer, add the mathematical model of the controlled object to the position loop

It is obtained through the frequency response test and is an approximation to the actual acceleration model G _p (s) of the system. The input of G _p (s) is the control variable u _a of the position controller, and the output contains the external position disturbance, while

The output of , does not contain external disturbances, by adding

By subtracting the output from G _p (s), the external equivalent position disturbance d _p (s) can be observed;

近似于一个积分环节，其形式如下：Among them, the position controlled object model

It is approximated by an integral link, and its form is as follows:

Step (6): Carry out the design of the position disturbance compensator: carry out the analysis of the stability of the system by C _fp (s), use the obtained constraints to design the parameters of C _fp (s), and add the designed position compensator to the system. in the disturbance observation loop of the position loop. The observed equivalent position disturbance d _p (s) is input to the position disturbance compensator C _fp (s), and the output is fed forward to the input of the position controller G _p (s).

Among them, the constraints of the position disturbance observer are as follows:

为对象辨识得到的加速度被控对象模型，

为对象辨识得到的位置被控对象模型，C_p,C_v,C_a分别为位置控制器，速度控制器和加速度控制器。in,

The acceleration controlled object model obtained for object identification,

C _p , C _v , and C _a are the position controller, the velocity controller and the acceleration controller, respectively.

Among them, the design form of the position disturbance observer is as follows:

为位置被控对象模型，K_fp,T₁,T₂均由设计者决定，与受到的扰动集中的低频段频率(1-5Hz)有关。in,

For the position plant model, K _fp , T ₁ , T ₂ are all determined by the designer, and are related to the low frequency (1-5Hz) in the concentrated disturbance.

Compared with the prior art, the present invention has the following advantages:

(1) Compared with the traditional multi-closed-loop control method, the present invention is based on the structure of the disturbance observer, adding an acceleration disturbance observer and a position disturbance observer respectively, and through the feedforward control of the disturbance compensator to improve the intermediate frequency and low frequency of the system. The purpose of anti-interference ability.

(2) The present invention provides clear regulations for the design forms of the acceleration disturbance compensator and the position disturbance compensator, and puts forward stability constraints for the parameter design of the position disturbance observer, which has good guiding significance for engineering implementation.

(3) The present invention can be directly added to the traditional multi-closed-loop stable control system, and effectively improves the anti-interference ability of the system without affecting the tracking ability of the original system.

(4) The present invention has a simple structure, is easy to implement, does not need to add additional sensors to the original stable control platform to measure disturbances, and is beneficial to reducing the cost of system hardware.

Description of drawings

Fig. 1 is a kind of multi-disturbance observer three-closed-loop stable tracking method based on acceleration and position disturbance information of the present invention;

Fig. 2 is the frequency domain comparison diagram of the disturbance suppression capability after the present invention is introduced into the traditional multi-closed loop;

FIG. 3 is a time-domain comparison diagram of stable accuracy after the present invention is introduced into the traditional multi-closed loop.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Figure 1 is a control block diagram of a multi-disturbance observer three-closed-loop stable tracking method based on acceleration and position disturbance information, which includes a feedforward compensation loop of the acceleration disturbance observer, a feedforward compensation loop of the position disturbance observer, Acceleration loop, velocity loop, and position loop; the disturbance observer structure based on acceleration disturbance information and position disturbance information is adopted, and the disturbance suppression capability of the system at medium frequency and low frequency is improved in a targeted manner. The specific implementation steps of the method are as follows:

Step (1): install a microelectromechanical accelerometer and a microelectromechanical gyroscope on the X axis and the Y axis of the stable control platform to measure the angular acceleration and angular velocity of the platform in the inertial space; the CCD camera obtains the light signal received by the stable control platform, To obtain the location information of the system;

Step (2): The frequency response test is performed on the acceleration controlled object of the stable control platform through the frequency response tester, the input is the voltage value, and the output is the sampled value of the accelerometer, and the object identification of the input and output model is performed to obtain the acceleration object. Charged model

设计加速度控制器C_a(s)；通过对加速度闭环的频响测试获得速度对象的被控模型

设计速度控制器C_v(s)；再通过对加速度闭环和速度闭环的频响测试获得位置对象的被控模型

设计位置控制器C_p(s)，这样就形成了加速度、速度、位置的三闭环系统。Step (3): realize the three closed loops of the stable control platform: according to the acceleration controlled object obtained by the fitting

Design the acceleration controller C _a (s); obtain the controlled model of the velocity object through the frequency response test of the closed-loop acceleration

Design the velocity controller C _v (s); then obtain the controlled model of the position object through the frequency response test of the acceleration closed-loop and velocity closed-loop

The position controller C _p (s) is designed so that a three closed-loop system of acceleration, velocity and position is formed.

是通过频响测试得到的，是对系统实际加速度模型G_a(s)的逼近；G_a(s)的输入是速度控制器的控制量u_a，这个输出包含了外界的加速度扰动，而

的输出不包含外界扰动，通过将

和G_a(s)的输出量相减，可以观测到外界的等效加速度扰动d_a(s)；将观测到的加速度扰动d_a(s)输入到加速度扰动补偿器C_fa(s)中，输出量前馈到加速度控制器C_a(s)的输入量中。Step (4): Add acceleration disturbance observer and disturbance compensator: Add the mathematical model of the controlled object in the acceleration loop

It is obtained through the frequency response test and is an approximation to the actual acceleration model of the system _Ga (s); the input of _Ga (s) is the control variable u _a of the speed controller, this output contains the external acceleration disturbance, and

The output of , does not contain external disturbances, by adding

By subtracting it from the output of G _a (s), the external equivalent acceleration disturbance d _a (s) can be observed; input the observed acceleration disturbance d _a (s) into the acceleration disturbance compensator C _fa (s) , the output is fed forward to the input of the acceleration controller C _a (s).

有纯微分环节存在如下：Among them, the mathematical model of the controlled object of the acceleration ring

There are pure differential elements as follows:

Among them, Ka is the gain of the controlled object of acceleration, ω _{n is} the turning frequency of the second-order link of the denominator of the controlled object of acceleration, ζ is the parameter in the second-order link of the denominator of the controlled object of acceleration, and T _a is the denominator of the controlled object of acceleration. The parameters in the order lag link, the above four parameters can be obtained from the object identification of the acceleration controlled object.

Among them, the design form of the acceleration disturbance compensator is as follows:

Among them, T _a is the parameter in the first-order lag link of the denominator of the acceleration controlled object, and K _fa , ξ _fa , and ω _fa are all determined by the designer and are related to the mid-range frequency in the concentrated disturbance.

是通过频响测试得到的，是对系统实际加速度模型G_p(s)的逼近。G_p(s)的输入是位置控制器的控制量u_a，这个输出包含了外界的位置扰动，而

的输出不包含外界扰动，通过将

和G_p(s)的输出量相减，可以观测到外界的等效加速度扰动d_p(s)；Step (5): Add a position disturbance observer: the same as adding an acceleration disturbance observer, add the mathematical model of the controlled object to the position loop

It is obtained through the frequency response test and is an approximation to the actual acceleration model G _p (s) of the system. The input of G _p (s) is the control variable u _a of the position controller, and the output contains the external position disturbance, while

The output of , does not contain external disturbances, by adding

By subtracting the output from G _p (s), the external equivalent acceleration disturbance d _p (s) can be observed;

近似于一个积分环节，其形式如下：Among them, the position controlled object model

It is approximated by an integral link, and its form is as follows:

Step (6): Carry out the design of the position disturbance compensator: carry out the analysis of the stability of the system by C _fp (s), use the obtained constraints to design the parameters of C _fp (s), and add the designed position compensator to the system. in the disturbance observation loop of the position loop. The observed disturbance d _p (s) is input to the position disturbance compensator C _fp (s), and the output is fed forward to the input of the position controller G _p (s).

Among them, the constraints of the position disturbance observer are as follows:

为对象辨识得到的加速度被控对象模型，

为对象辨识得到的位置被控对象模型，C_p,C_v,C_a分别为位置控制器，速度控制器和加速度控制器。in,

The acceleration controlled object model obtained for object identification,

C _p , C _v , and C _a are the position controller, the velocity controller and the acceleration controller, respectively.

Among them, the design form of the position disturbance observer is as follows:

为位置被控对象模型，K_fp,T₁,T₂均由设计者决定，与受到的扰动集中的低频段频率有关。in,

For the position plant model, K _fp , T ₁ , and T ₂ are all determined by the designer, and are related to the low-frequency frequencies in the concentrated disturbance.

The design process and effect of the present invention are described in detail below by taking a stable control platform experimental system as an example:

近似相等：(1) The acceleration transfer function model of the system measured by the frequency response tester is, in the design process, it can be considered that G _a (s) and

approximately equal:

(2) Through the acceleration object model, the acceleration, velocity and position controllers can be designed as follows to realize the traditional multi-closed loop:

(3) Sweep the system through the frequency response tester. After identification, the transfer function of the position model is obtained as:

(4) After the traditional multi-loop closed-loop control is realized, the feedforward compensation controller C _fa (s) of the designed acceleration loop disturbance observer is:

(5) After adding the disturbance observer of the acceleration loop, the feedforward compensation controller C _fp (s) of the designed position loop disturbance observer is:

(6) FIG. 2 is a frequency domain comparison diagram of the stability accuracy after the present invention is introduced into the traditional three-closed loop. Compared with the simple three-closed-loop method, it can be found that the anti-interference ability of the system at medium frequency and low frequency is obviously enhanced after the introduction of the acceleration disturbance observer and the position disturbance observer.

(7) Figure 3 is a frequency domain comparison diagram of the disturbance suppression capability after the present invention is introduced into the traditional three-closed loop. Compared with the traditional three closed-loop method, it can be found that the stability accuracy of the system is significantly improved after the introduction of the acceleration disturbance observer and the position disturbance observer.

Claims (3)

1. a multi-disturbance observer three closed-loop stable tracking method based on acceleration and position disturbance information, is characterized in that: its concrete implementation steps are as follows: Step (1): install a microelectromechanical accelerometer and a microelectromechanical gyroscope on the X axis and the Y axis of the stable control platform to measure the angular acceleration and angular velocity of the platform in the inertial space; the CCD camera obtains the light signal received by the stable control platform, To obtain the location information of the system; Step (2): The frequency response test is performed on the acceleration controlled object of the stable control platform by the frequency response tester, the input is the voltage value, the output is the sampled value of the accelerometer, and the acceleration controlled object is obtained by object identification of the input and output model. The controlled model of the object

Step (3): realize the three closed loops of the stable control platform: according to the acceleration controlled object obtained by the fitting

Design the acceleration controller C _a (s); obtain the controlled model of the velocity object through the frequency response test of the closed-loop acceleration

Design the velocity controller C _v (s); then obtain the controlled model of the position object through the frequency response test of the acceleration closed-loop and velocity closed-loop

Design the position controller C _p (s), thus forming a three closed-loop system of acceleration, velocity and position; Step (4): Add acceleration disturbance observer and disturbance compensator: Add the mathematical model of the controlled object in the acceleration loop

It is obtained through the frequency response test and is an approximation to the actual acceleration model of the system _Ga (s); the input of _Ga (s) is the control variable u _a of the speed controller, and the output of _Ga (s) includes the external acceleration disturbance, while

The output of , does not contain external disturbances, by adding

By subtracting it from the output of G _a (s), the external equivalent acceleration disturbance d _a (s) can be observed; input the observed acceleration disturbance d _a (s) into the acceleration disturbance compensator C _fa (s) , the output is fed forward to the output of the acceleration controller C _a (s); Wherein, the design form of the acceleration disturbance compensator in step (4) is as follows:

Among them, T _a is the parameter in the first-order lag link of the denominator of the acceleration controlled object, and K _fa , ξ _fa , ω _fa are all determined by the designer, and are related to the mid-band frequency 5-20 Hz where the disturbance is concentrated; Step (5): Add a position disturbance observer: the same as adding an acceleration disturbance observer, add the mathematical model of the controlled object to the position loop

It is obtained through the frequency response test and is an approximation to the actual acceleration model G _p (s) of the system; the input of G _p (s) is the control variable u _a of the position controller, and the output includes the external position disturbance, while

The output of , does not contain external disturbances, by adding

By subtracting the output from G _p (s), the external equivalent position disturbance d _p (s) can be observed; Step (6): Carry out the design of the position disturbance compensator: carry out the analysis of the stability of the system by C _fp (s), use the obtained constraints to design the parameters of C _fp (s), and add the designed position compensator to the system. In the disturbance observation loop of the position loop; the observed equivalent position disturbance d _p (s) is input into the position disturbance compensator C _fp (s), and the output is fed forward to the output of the position controller G _p (s) ; Among them, the stability constraints of the position disturbance observer in step (6) are as follows:

in,

The acceleration controlled object model obtained for object identification,

C _p , C _v , C _a are the position controller, the velocity controller and the acceleration controller respectively; The design form of the position disturbance observer in step (6) is as follows:

in,

For the position plant model, K _fp , T ₁ , and T ₂ are all determined by the designer, and are related to the low frequency 1-5 Hz in the concentrated disturbance. 2. a kind of multi-disturbance observer three-closed-loop stable tracking method based on acceleration and position disturbance information according to claim 1, is characterized in that: the mathematical model of acceleration controlled object in step (2)

There are pure differential elements as follows:

Among them, Ka is the gain of the controlled object of acceleration, ω _{n is} the turning frequency of the second-order link of the denominator of the controlled object of acceleration, ζ is the parameter in the second-order link of the denominator of the controlled object of acceleration, and T _a is the denominator of the controlled object of acceleration. The parameters in the order lag link, the above four parameters can be obtained from the object identification of the acceleration controlled object. 3. a kind of multi-disturbance observer three-closed-loop stable tracking method based on acceleration and position disturbance information according to claim 1, is characterized in that: the position controlled object model in step (5)

It is approximated by an integral link, and its form is as follows:

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