CN107272411A - Plug-in acceleration feedback fast reflecting mirror light beam stability control method - Google Patents

Abstract

The invention relates to a fast mirror beam stabilization control method with plug-in acceleration feedback. The core idea of the method is to use the acceleration sensor as observation compensation for disturbance after the double closed-loop implementation of the gyroscope and CCD, and then directly eliminate the disturbance to the base The effect of acceleration. This method is independent of the outer loop in design, that is, the realization of the inner acceleration loop and the outer gyro position loop do not affect each other, and can be directly connected to the system as a plug-in when necessary without causing damage to the system characteristics, so it is called Plug-in acceleration feedback control method. In the control framework, this method only needs the characteristics of the acceleration object and a nearly constant acceleration controller, which simplifies the control process and controller design, avoids the precise zero-pole compensation of the traditional acceleration feedback method, and makes the method more effective in engineering. more easily realized. Compared with the traditional three-closed-loop control method, this method can effectively improve the disturbance suppression capability of the system at intermediate frequencies and improve system performance.

Description

A fast mirror beam stabilization control method based on plug-in acceleration feedback

technical field

The invention belongs to the field of photoelectric system tracking control, and in particular relates to a plug-in type acceleration feedback fast mirror light beam stabilization control method, which is used to simplify the system acceleration control design and improve the system disturbance suppression ability.

Background technique

As the core component of the optical precision tracking control system, the fast mirror has been widely used in cutting-edge optical systems such as long-distance laser communication, adaptive optics, and space telescope systems. With the continuous expansion of application fields, it is gradually installed on motion platforms such as spacecraft, aircraft, and automobiles. The disturbance of the base on the motion platform will be directly transmitted to the mirror surface of the fast mirror, thereby reducing the stable tracking accuracy of the deflected beam and greatly damaging the system performance. The disturbance on the moving carrier has a wide frequency band. The traditional control method mainly relies on the gyroscope and CCD sensor for inertial stabilization of the fast mirror, but its anti-disturbance ability is limited and cannot meet the higher stability control requirements. With the development of the accelerometer, it has the advantages of small size, light weight, and low power consumption, which makes the application of the accelerometer on the fast mirror possible. The document "Inertial sensor-based multi-loop control of fast steering mirror for line of sight stabilization" (Optical Engineering, Vol(55), 2016) uses accelerometers, gyroscopes and CCDs to achieve three-loop stabilization, which improves the stability of fast mirrors. However, because there are two differentials in the acceleration object characteristics of the fast mirror, for the controller in the acceleration loop, full compensation cannot be realized, which leads to certain difficulties in the design of the acceleration controller. The upper limit of use is relatively large.

Contents of the invention

In view of the deficiencies in the current fast mirror disturbance suppression control method, the purpose of the present invention is to provide a fast mirror beam stabilization control method with plug-in acceleration feedback, simplify the control framework and controller design, and further improve system performance. The core idea of this method is to use the acceleration sensor as the observation compensation for the disturbance after the double closed loop of the gyro and CCD is realized, and then directly eliminate the influence of the disturbance acceleration on the base. Because the accelerometer has the natural advantages of small size and high bandwidth, and the perturbation observation method itself requires a higher bandwidth for object identification, so this realizes the superposition of the advantages of the sensor and the control method, and the effect is better. Since this method is independent from the outer loop in design, that is, the realization of the inner acceleration loop and the outer gyro position loop do not affect each other, so this method can be directly connected to the system as a plug-in when necessary without causing damage to the system characteristics. Therefore, it is called plug-in acceleration feedback control method. In the control framework, this method only needs the characteristics of the acceleration object and a nearly constant acceleration controller, which simplifies the control process and controller design, avoids the precise zero-pole compensation of the traditional acceleration feedback method, and makes the method more effective in engineering. It is more advantageous to realize. This method still uses the idea of feedback to theoretically enhance the robustness of the system.

To achieve the purpose of the present invention, the present invention provides a fast mirror beam stabilization control method of plug-in acceleration feedback, and its specific implementation steps are as follows:

Step (1): Install an accelerometer, a gyro inertial sensor and a CCD position sensor in the fast mirror tracking control system to measure the deflection angular acceleration, angular velocity and angular position of the fast mirror. The sampling frequency of the inertial sensor is generally high, which is mainly used to realize a high-bandwidth linear inner loop and provide a linear controlled object for the outer loop;

Step (2): Test the acceleration, velocity and frequency object characteristics of the platform with a frequency response tester. The input is the controller output value, and the output is the sensor sampling value. By identifying the measured object, the object model G is finally obtained. _a (s) and G _v (s);

Step (3): On the basis of obtaining the controlled object model G _v (s), design the inner loop speed controller C _v (s) to realize the speed feedback closed loop, and then test the speed of the inner loop closed loop by the frequency response tester again The object model, the input is a given position, and the output is a CCD quantity. This object model is the controlled object model of the outer loop, called G _p (s), and then the CCD loop controller C _p (s) can be designed, which constitutes Traditional double closed-loop control;

Step (4): Add plug-in acceleration feedback control. First, the output drive value of the speed controller C _v (s) is not only directly sent to the hardware driver, but also sent to a virtual object at the same time So as to obtain an ideal output acceleration; then subtract the ideal output from the acceleration value measured by the actual accelerometer, so that the external disturbance can be observed by taking the difference between a real output with disturbance and an ideal output without disturbance;

Step (5): Input the estimated external disturbance into the acceleration feedback controller to output the real feed-forward amount, and finally add the feed-forward amount directly to the given speed controller, thus realizing the overall plug-in Acceleration feedback control.

Among them, the inner loop speed controller C _v (s) and the outer loop CCD position controller C _p (s) in step (3) are both designed as PI controllers, and their model references are as follows:

Among them, K _P is the proportional gain, and K _I is the integral gain.

Wherein, in step (4), since the accelerometer is sensitive to medium and high frequencies, the accuracy of the measured object is relatively high, and it can be considered that the virtual object is equivalent to the real object. In addition, since the observed external disturbance is obtained based on the accelerometer, the observed disturbance is the disturbance moment.

Among them, the feedforward controller C′ _a (s) in step (5) is theoretically a constant equivalent, but because the observed data contains certain noise, therefore, C′ _a (s) is designed as follows with a first-order filter link The controller model:

Among them, T _f is the filtering bandwidth factor of the filter. After the feedforward compensator is designed as the above model, the disturbance suppression capability of the entire feedback loop exhibits high-pass filtering characteristics, thereby effectively improving the low-frequency error suppression capability of the system, that is, the mid-low frequency tracking performance.

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

(1) Compared with the traditional direct acceleration feedback control method, the invention adopts the idea based on the disturbance observer, avoids the controller design method directly using zero-pole compensation, can effectively reduce the difficulty of realizing the acceleration loop, and optimizes the control structure. Improve its practicability in practical engineering;

(2) The realization of the acceleration feedback in this method has no influence on the external speed position loop, and is independent in design, and can be selectively added to the control loop as a plug-in, which improves the adaptability of the system in different situations;

(3) This method can effectively improve the intermediate frequency error suppression performance of the system, improve the robustness of the system, and meet the demand for stable precision in actual engineering.

Description of drawings

Fig. 1 is the control block diagram of the fast mirror beam stabilization control method of a kind of plug-in type acceleration feedback of the present invention;

Fig. 2 is a comparison diagram of error suppression of a plug-in type acceleration feedback fast mirror beam stabilization control method of the present invention.

detailed description

The specific implementation manners of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, it is a control block diagram of a plug-in acceleration feedback fast mirror beam stabilization control method, which includes an internal acceleration feedback closed loop, a gyro speed closed loop and a CCD position outer loop. The core idea of this method is to introduce a disturbance observer into the acceleration loop, use the model to estimate the disturbance torque, and then perform feedback compensation. Due to the optimization of the control block diagram, the accelerometer can be designed as a constant controller in theory. The concrete implementation steps of adopting described method to realize closed-loop control are as follows:

Step (1): Install an accelerometer, a gyro inertial sensor and a CCD position sensor in the fast mirror tracking control system to measure the deflection angular acceleration, angular velocity and angular position of the fast mirror. The sampling frequency of the inertial sensor is generally high, which is mainly used to realize a high-bandwidth linear inner loop and provide a linear controlled object for the outer loop;

Step (2): Test the acceleration, velocity and frequency object characteristics of the platform with a frequency response tester. The input is the controller output value, and the output is the sensor sampling value. By identifying the measured object, the object model G is finally obtained. _a (s) and G _v (s);

Step (3): On the basis of obtaining the controlled object model G _v (s), design the inner loop speed controller C _v (s) to realize the speed feedback closed loop, and then test the speed of the inner loop closed loop by the frequency response tester again The object model, the input is a given position, and the output is a CCD quantity. This object model is the controlled object model of the outer loop, called G _p (s), and then the CCD loop controller C _p (s) can be designed, which constitutes Traditional double closed-loop control;

Step (4): Add plug-in acceleration feedback control. First, the output drive value of the speed controller C _v (s) is not only directly sent to the hardware driver, but also sent to a virtual object at the same time So as to obtain an ideal output acceleration; then subtract the ideal output from the acceleration value measured by the actual accelerometer, so that the external disturbance can be observed by taking the difference between a real output with disturbance and an ideal output without disturbance;

Step (5): Input the estimated external disturbance into the acceleration feedback controller to output the real feed-forward amount, and finally add the feed-forward amount directly to the given speed controller, thus realizing the overall plug-in Acceleration feedback control.

Among them, the inner loop speed controller C _v (s) and the outer loop CCD position controller C _p (s) in step (3) are both designed as PI controllers, and their model references are as follows:

Among them, K _P is the proportional gain, and K _I is the integral gain.

Wherein, in step (4), since the accelerometer is sensitive to medium and high frequencies, the accuracy of the measured object is relatively high, and it can be considered that the virtual object is equivalent to the real object. In addition, since the observed external disturbance is obtained based on the accelerometer, the observed disturbance is the disturbance moment.

Among them, the feedforward controller C′ _a (s) in step (5) is theoretically a constant equivalent, but because the observed data contains certain noise, therefore, C′ _a (s) is designed as follows with a first-order filter link The controller model:

Among them, T _f is the filtering bandwidth factor of the filter. After the feedforward compensator is designed as the above model, the disturbance suppression capability of the entire feedback loop exhibits high-pass filtering characteristics, thereby effectively improving the low-frequency error suppression capability of the system, that is, the mid-low frequency tracking performance.

The design process and effect of the present invention are described in detail below with a fast mirror tracking platform experimental system as an example:

(1) The acceleration and speed of the system measured by the frequency response tester are as follows:

(2) Then the inner loop speed controller can be designed as C _v (s) and the outer loop CCD controller C _p (s) to realize the traditional double-loop closed loop, wherein the CCD frequency is 50Hz, and the delay is 3 frames (60ms);

(3) On the basis of completing the traditional double closed-loop, design a plug-in acceleration feedback controller. Through theoretical calculation, the gain of the acceleration controller is 0.65, and the filter bandwidth can be designed to about 100Hz. Therefore, the real acceleration controller can be designed as follows ;

(4) Fig. 2 is a comparison diagram of the disturbance suppression capability of the present invention. Under the same conditions, it can be clearly seen that after adopting the acceleration feedback closed-loop control based on the disturbance observer, the error suppression ability of the system at low frequencies is equivalent to that of the traditional three-closed-loop method, but the error suppression ability at intermediate frequencies is greatly improved, while ensuring The system stability feature continues the high-frequency error suppression ability.

Claims (4)

1. a kind of fast anti-mirror beamstability control method of plug-in type accelerator feedback, it is characterised in that：Its specific implementation step It is as follows：

Step (1)：Accelerometer, gyroscopic inertia sensor and CCD position sensors are installed in fast anti-mirror tracking control system, Deflection angular acceleration, angular speed and Angle Position amount to measure fast anti-mirror；Inertial sensor is to realize a high band the wide line Property inner ring, a linear controlled device is provided for outer shroud；

Step (2)：Acceleration, the speed in frequency plant characteristic of platform are tested by frequency response tester, inputs and is Controller output valve, is output as sensor sample value, by being recognized to measured object, final to obtain object model G_a And G (s)_v(s)；

Step (3)：Getting plant model G_v(s) on the basis of, inner loop velocity controller C is designed_v(s) realize that speed is anti- Closed loop is presented, then again by the object model after frequency response tester test speed inner ring closed loop, is inputted as given position, CCD amounts are output as, this object model is outer shroud plant model, referred to as G_p(s) CCD ring controllers C can, then be designed_p(s), Thus constitute traditional double-closed-loop control；

Step (4)：Plug-in type acceleration feedback control is added, first speed control C_v(s) output driving amount is removed and directly sent Outside to hardware driving, also a virtual objects are sent out to simultaneouslySo as to obtain a preferable output acceleration Amount；Then this preferable output quantity is subtracted with the acceleration magnitude measured by actual acceleration meter, is so truly contained using one and disturbed Dynamic output quantity and a preferable undisturbed output quantity ask poor Observable to go out outside disturbance quantity；

Step (5)：The estimation external disturbance amount is input in acceleration feedback control device then output and obtains true feedforward amount, most Afterwards the feedforward amount be directly added into speed control it is given in, so just realize overall plug-in type accelerator feedback control System.

2. a kind of fast anti-mirror beamstability control method of plug-in type accelerator feedback according to claim 1, its feature It is：Wherein, inner loop velocity controller C in step (3)_v(s) with outer shroud CCD positioners C_p(s) PI controls are designed to Device, its model reference is as follows：

<mrow> <msub> <mi>C</mi> <mrow> <mi>P</mi> <mi>I</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>s</mi> <mo>)</mo> </mrow> <mo>=</mo> <msub> <mi>K</mi> <mi>I</mi> </msub> <mo>.</mo> <mfrac> <mrow> <msub> <mi>K</mi> <mi>P</mi> </msub> <mi>s</mi> <mo>+</mo> <mn>1</mn> </mrow> <mi>s</mi> </mfrac> </mrow>

Wherein, K_PFor proportional gain, K_IFor storage gain.

3. a kind of fast anti-mirror beamstability control method of plug-in type accelerator feedback according to claim 1, its feature It is：Wherein, so the object precision measured by it is higher, it can recognize because accelerometer is sensitive to medium-high frequency in step (4) It is that virtual objects and real object are suitable；In addition, the external disturbance amount observed is by being then based on obtained by accelerometer, so seeing The disturbance quantity measured is disturbing moment amount.

4. a kind of fast anti-mirror beamstability control method of plug-in type accelerator feedback according to claim 1, its feature It is：Wherein, feedforward controller C in step (5)_a' (s) is theoretically a constant equivalent, but is due to observed data Include certain noise, therefore, C_a' (s) is designed as such as the controller model of lower band first-order filtering link：

<mrow> <msubsup> <mi>C</mi> <mi>a</mi> <mo>&amp;prime;</mo> </msubsup> <mrow> <mo>(</mo> <mi>s</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <msub> <mi>K</mi> <mi>f</mi> </msub> <mrow> <msub> <mi>T</mi> <mi>f</mi> </msub> <mi>s</mi> <mo>+</mo> <mn>1</mn> </mrow> </mfrac> </mrow>

Wherein, T_fFor filter filtering bandwidth factor, when the design of Compensator that feedovers is as above model after, whole backfeed loop is disturbed High-pass filtering characteristic is presented in dynamic rejection ability, so that the low frequency aberration rejection ability of strong raising system, that is, middle low frequency Tracking performance.