CN103309363A - Two-way control method for eliminating imaging rotation of scanning imaging system - Google Patents

Abstract

The invention discloses a two-way control method for eliminating imaging rotation of a scanning imaging system, relates to the technical field of imaging, and solves the problems that the existing imaging rotation elimination methods using mechanical linkage or combination of a servo motor and the mechanical linkage results in low transmission accuracy, or meanwhile strictly coordinated movement of a scanning mirror and a rotation eliminating mechanism is hard to achieve by adopting the servo motor to drive to eliminate the imaging rotation. The two-way control method includes steps of adopting a single motor command tracking controller to receive a rotation command of the scanning mirror, and controlling rotation of a scanning mirror servo motor and a rotation eliminating mechanism servo motor respectively; adopting a torque estimator to estimate equivalent driving torques acted on a motor shafting by the single motor command tracking controller to provide torque information for a four-channel two-way controller. According to the arrangement, positions and torques between two servo systems of the scanning mirror servo motor and the rotation eliminating mechanism servo motor are mix-controlled to realize electrical linkages of the same. Besides, coordinated movement performance between the scanning mirror and the rotation eliminating mechanism in a servo motor rotation eliminating system is improved.

Description

A bidirectional control method for eliminating image rotation in scanning imaging system

technical field

The invention relates to a motion control method for eliminating image rotation of a scanning imaging system, belonging to the technical field of imaging.

Background technique

In an imaging system, the field of view of an optical lens limits the imaging range. The method of horizontal scanning is an effective way to expand the coverage of the imaging system. In order to reduce the moment of inertia of the scanning mechanism, a 45° scanning mirror is usually installed in front of the lens, and the horizontal scanning is realized by controlling the rotation of the scanning mirror. However, the rotation of the scanning mirror will cause the image of the target scene to rotate on the image plane. In order to ensure the image integrity of scanning imaging, a high-precision derotation system must be designed.

In order to eliminate image rotation, a derotation prism is often used to cooperate with a 45° scanning mirror, so that the rotation angle of the derotation prism is kept at half of the rotation angle of the 45° scanning mirror; another method is to directly rotate the CCD or CMOS without using a derotation prism. The imaging component synchronizes the angular position and angular velocity of the imaging component with the scanning motion of the scanning mirror so as to eliminate the image rotation. At present, to realize the cooperative movement of the derotation prism or imaging component and the 45° scanning mirror, mechanical linkage, or a method of motor servo combined with mechanical linkage is mostly used. The mechanical linkage method is to use gears, friction wheels, sheaves and cable transmission to make the derotation prism or imaging component rotate with the 45° scanning mirror. However, this method leads to a larger shafting size of the camera, which has great limitations in practical applications. Moreover, the linkage mechanism also has problems such as backlash, slippage, and loose steel cables. The transmission accuracy is difficult to be guaranteed, and frequent maintenance is required.

The motor servo method is to drive the 45° scanning mirror, derotation prism or imaging component respectively with a motor servo system. When the scanning mirror rotates, the same rotation command is multiplied by a certain ratio and sent to the derotation prism or imaging component servo system. The outstanding advantages of this method are simple mechanical design, no need to add mechanical shafting, small size and light weight, especially suitable for aerospace cameras and other occasions that require high volume and weight. However, since the moments of inertia, frictional moments and external disturbances of different servo systems are not exactly the same, it is difficult to realize the strict coordinated motion of the scanning mirror and the derotation mechanism. Therefore, in practical applications, a linkage mechanism is still added between the motor servo system to improve the precision of the coordinated rotation between the scanning mirror and the derotation mechanism, so that the advantages of the motor servo derotation method cannot be fully utilized.

Contents of the invention

The present invention solves the existing problem of using mechanical linkage, or motor servo combined with mechanical linkage to eliminate image rotation, resulting in low transmission accuracy, or adopting motor servo drive, but at the same time it is difficult to realize the strict coordinated movement of the scanning mirror and the derotation mechanism. , providing a bidirectional control method for eliminating image rotation in a scanning imaging system.

A bidirectional control method for eliminating image rotation in a scanning imaging system, comprising a single motor command tracking controller A, a single motor command tracking controller B, two equivalent torque estimators and a four-channel bidirectional controller, the single motor The command tracking controller A and the single-motor command tracking controller B are respectively used for tracking the commands by the scanning mirror servo motor and the derotation mechanism servo motor; the equivalent torque estimator provides torque information for the calculation of the four-channel bidirectional controller; The four-channel bidirectional controller is used to coordinate the rotation of the scanning mirror servo motor and the derotation mechanism servo motor; the specific method is:

以及消旋机构伺服电机的角位置信息θ₂、角速度信息

然后将消旋机构伺服电机的角位置信息乘以比例系数a后与扫描镜伺服电机的角位置信息作差，获得位置差值aθ₂-θ₁；将扫描镜伺服电机角位置信息乘以比例系数1/a后与消旋机构伺服电机的角位置信息作差，获得位置差值θ₁/a-θ₂；将扫描镜伺服电机的角速度信息和消旋机构伺服电机的角速信息计算速度信息差

和 ${\stackrel{\·}{\mathrm{\θ}}}_1/a-{\stackrel{\·}{\mathrm{\θ}}}_2;$ Step 1. Obtain the angular position information θ ₁ and the angular velocity information of the scanning mirror servo motor according to the scanning mirror rotation command

And the angular position information θ ₂ and angular velocity information of the servo motor of the derotation mechanism

Then multiply the angular position information of the servo motor of the derotation mechanism by the proportional coefficient a and make a difference with the angular position information of the scanning mirror servo motor to obtain the position difference aθ ₂ -θ ₁ ; multiply the angular position information of the scanning mirror servo motor by the ratio After the coefficient 1/a, make a difference with the angular position information of the servo motor of the derotation mechanism to obtain the position difference θ ₁ /a-θ ₂ ; the angular velocity information of the servo motor of the scanning mirror and the angular velocity information of the servo motor of the derotation mechanism are used to calculate the speed poor information

and ${\stackrel{\&Center\; Dot;}{\mathrm{\θ}}}_1/a-{\stackrel{\·}{\mathrm{\θ}}}_2;$

Step 2. The single-motor command tracking controller A obtains the command tracking control amount u _c1 of the scanning mirror servo motor according to the difference between the scanning mirror rotation command and the angular position information of the scanning mirror servo motor; the single-motor command tracking controller B according to the The difference between the rotation command of the scanning mirror and the angular position information of the servo motor of the derotation mechanism multiplied by the proportional coefficient a is used to obtain the command tracking control amount u _c2 of the servo motor of the derotation mechanism;

Step 3, calculating the estimated equivalent torque of the scanning mirror servo motor and the derotation mechanism servo motor;

The specific process is as follows: the angular position information θ1 of the scanning mirror servo motor obtained in step ₁ is passed through the transfer function of the product of the standard motor inverse model and the low-pass filter in the equivalent torque estimator, and then passed through the low-pass filter with the previous cycle The difference obtained by subtracting the bidirectional control quantity u _b1 of the scanning mirror servo motor of the scanning mirror servo motor is used as the output value of the equivalent torque estimator on the scanning mirror servo motor; the angular position information θ ₂ of the derotation mechanism servo motor obtained according to step 1 After the transfer function of the product of the standard motor inverse model in the equivalent torque estimator and the product of the low-pass filter, the difference obtained by subtracting from the bidirectional control variable u _b2 of the derotation mechanism servo motor that passed the low-pass filter in the previous cycle As the output value of the equivalent torque estimator on the derotation mechanism servo motor;

Step 4. Recalculate the scanning mirror servo motor with the position difference aθ ₂ -θ ₁ and θ ₁ /a-θ ₂ obtained in step 1 and the equivalent torque estimates of the scanning mirror servo motor and derotation mechanism servo motor obtained in step 3. The bidirectional control quantity u _b1 of the motor and the bidirectional control quantity u _b2 of the servo motor of the derotation mechanism;

Step 5. Combining the command tracking control quantity u _c1 of the scanning mirror servo motor obtained in step 2 and the command tracking control quantity u _c2 of the derotation mechanism servo motor with the bidirectional control quantity u _b1 and elimination of the scanning mirror servo motor obtained in step 4 respectively The two-way control quantity u _b2 of the rotary mechanism servo motor is superimposed, and the superimposed output value acts on the corresponding motor.

Beneficial effects of the present invention:

1. The present invention does not require the assistance of a mechanical linkage mechanism, and realizes strict coordinated motion between the scanning mirror servo system with completely isolated mechanical transmission and the derotation mechanism servo system. It can not only reduce the volume and weight of the scanning imaging system, but also effectively avoid problems such as backlash, slipping, and loosening of flexible transmission elements in the mechanical linkage method, and effectively improve the maintainability of the entire scanning imaging system.

2. The present invention adopts the idea of two-way control, and has outstanding advantages in synergy between the two sets of motor servo systems compared with the existing method of respectively performing instruction tracking control on the scanning mirror and the derotation servo system. The invention can effectively ensure the coordination of the motion of the scanning mirror and the servo system of the derotation mechanism with different moment of inertia, affected by different friction torques and external disturbances, and improve the precision of image rotation elimination.

Description of drawings

Fig. 1 is a schematic diagram of an algorithm of a bidirectional control method for eliminating image rotation in a scanning imaging system according to the present invention;

Fig. 2 is a functional block diagram of equivalent moment estimation in a bidirectional control method for eliminating image rotation in a scanning imaging system according to the present invention;

3 is a schematic diagram of the hardware structure of a bidirectional control method for eliminating image rotation in a scanning imaging system according to the present invention;

FIG. 4 is a workflow flowchart of software for a bidirectional control method for eliminating image rotation in a scanning imaging system according to the present invention.

Detailed ways

Specific Embodiments 1. This embodiment is described in conjunction with FIGS. 1 to 4. The 45° scanning mirror of the imaging system in the two-way control method for eliminating image rotation in the scanning imaging system described in this embodiment is driven by a set of motor servo system , called the scanning mirror servo motor; the derotation prism or imaging component is driven by another set of motor servo system, called the derotation mechanism servo motor; there is no mechanical connection between the two, and it is controlled by a four-channel bidirectional controller, that is, a The two-way control algorithm realizes the coordinated movement of two sets of servo systems.

Specifically include: two single-motor command tracking controllers, two equivalent torque estimators, and a position controller in the four-channel bidirectional controller; the single-motor command tracking controller A acting on the scanning mirror servo motor receives the scanning mirror rotation Command, control the 45° scanning mirror to rotate according to the angular position or angular velocity planned by the command; the single motor command tracking controller B acting on the servo motor of the derotation mechanism receives the same rotation command of the scanning mirror, and controls the servo motor of the derotation mechanism according to the scanning The mirror rotation command rotates in a certain ratio.

Two equivalent torque estimators are designed for the scanning mirror servo motor and the derotation mechanism servo motor respectively, and realize the estimation of the equivalent torque driving the two motors, and provide torque information for the four-channel bidirectional controller. The four-channel bidirectional controller connects the two sets of motor servo systems as a whole at the control level, so that the rotation angle and angular velocity of the two are exactly the same, or in a certain ratio; so that there is no mechanical linkage between the imaging component and the scanning mirror. The movement of the derotation prism meets the requirement of derotation.

The four-channel bidirectional controller includes: a position channel sent from the scanning mirror servo motor to the servo motor of the derotation mechanism; a torque channel sent from the equivalent torque estimator on the scanning mirror servo motor to the servo motor of the derotation mechanism; The position channel sent from the servo motor of the derotation mechanism to the servo motor of the scanning mirror; the torque channel sent from the equivalent torque estimator on the derotation mechanism to the servo motor of the scanning mirror; and the position controller under the four-channel bidirectional controller.

This embodiment will be described in conjunction with FIG. 1 . There may be a gap between the equivalent moment of inertia and damping parameters J ₁ and B ₁ of the scanning mirror servo motor and the equivalent moment of inertia and damping parameters J ₂ and B ₂ of the derotation mechanism servo motor. difference. The single-motor command tracking controller A and the single-motor command tracking controller B are position/speed tracking controllers designed for two independent servo systems, which realize the desired movement of the scanning mirror servo motor and the derotation mechanism servo motor. command (mirror rotation command). Two single-motor command-tracking controllers adopt lead-lag network correction to obtain the command-tracking control quantities u _c1 and u _c2 of the two motors. Assuming that the rotation command of the scanning mirror of the imaging system is r, and the rotation angles of the two motors are θ ₁ and θ ₂ respectively, then the process of calculating the control quantities u _c1 and u _c2 by the single motor command tracking controller of the two motors is: u _c1 =(r-θ ₁ )(τ ₁₁ s+1)(τ ₂₁ s+1)/[(T ₁₁ s+1)(T ₂₁ s+1)] and u _c2 =(r-aθ ₂ )(τ ₁₂ s+1)(τ ₂₂ s+1)/[(T ₁₂ s+1)(T ₂₂ s+1)], where s is the Laplacian operator, T ₁₁ >τ ₁₁ >τ ₂₁ >T ₂₁ is the lead-lag network parameter of the scanning mirror servo system, and T ₁₂ >τ ₁₂ >τ ₂₂ >T ₂₂ is the lead-lag network parameter of the derotation mechanism servo system. In Fig. 1, the position controller C _p (s) in the bidirectional controller is a proportional differential controller, which is used to coordinate the rotation of the scanning mirror servo motor and the derotation mechanism motor; the equivalent disturbances d1 and d2 are respectively acting on the scanning mirror The equivalent disturbance on the servo motor and the servo motor of the derotation mechanism, the equivalent disturbance includes the external friction torque, disturbance torque, and the mismatch between the actual model of the motor and the model shown in the figure.

This embodiment is described in conjunction with Figure 2. The equivalent torque estimator is the remaining amount estimation after the control torque (generated by the single motor controller) acting on the motor overcomes the equivalent disturbance and the inertia moment and damping torque caused by the mismatch of parameters come out. The torque estimators of the two motors use the same parameters J and B, which describe a standard motor model. Therefore, both motors have deviations between the actual equivalent inertia and damping and the parameters adopted by the algorithm ΔJ ₁ =J ₁ -J, ΔJ ₂ =J ₂ -J, ΔB ₁ =B ₁ -B,ΔB ₂ =B ₂ -B. Wherein, the low-pass filter is g ² /(s ² +2gs+g ² ), and the larger the parameter g, the higher the cut-off frequency. In the low frequency domain, the low-pass filter can be viewed as a proportional section with a gain of 1. Then the outputs of the two equivalent moment estimators are: $u_{\mathrm{cl}}+d_1-\mathrm{\Δ}{J}_1{\stackrel{\&Center\; Dot;\&Center\; Dot;}{\mathrm{\θ}}}_1-\mathrm{\Δ}{B}_1{\stackrel{\·}{\mathrm{\θ}}}_1$ and $u_{c2}+d_2-\mathrm{\Δ}{J}_2{\stackrel{\&Center\; Dot;\&Center\; Dot;}{\mathrm{\θ}}}_2-\mathrm{\Δ}{B}_2{\stackrel{\&Center\; Dot;}{\mathrm{\θ}}}_2.$

The four-channel bidirectional controller utilizes the angular position information and torque information of the servo motor of the scanning mirror and the servo motor of the derotation mechanism to realize the coordination of the motions of the two (moving according to a certain ratio a, and the determination of a is determined according to the specific derotation scheme, such as If the servo motor of the derotation mechanism drives a derotation prism, then a is 2; if the servo motor of the derotation mechanism drives an imaging component such as a CCD or CMOS, then a is 1). There are two position channels and two torque channels in the four-channel bidirectional controller, which are the angular position information provided by the scanning mirror servo motor to the derotation mechanism motor, the angular position information provided by the derotation mechanism servo motor to the scanning mirror motor, The torque information provided by the scanning mirror servo motor to the derotation mechanism servo motor, and the torque information provided by the derotation mechanism servo motor to the scanning mirror servo motor.

There is a position controller under the four-channel bidirectional controller, and the corresponding position control amount is calculated according to the angular position and angular velocity information difference between the scanning mirror servo motor and the derotation mechanism servo motor. The controller adopts a proportional-differential form, and the proportional gain and differential gain are respectively set as K _p and K _d . Under the action of the four-channel bidirectional control, the dynamic characteristics of the scanning mirror servo system and the derotation mechanism servo system are respectively:

$\mathrm{<span\; class="notranslate">\; J</span>}{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; B</span>}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; a</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; a</span>}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}$

${\mathrm{<span\; class="notranslate">\; J</span>}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; (</span>\frac{{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; -</span>{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; cl</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Then under the four-channel two-way control, the left and right ends of the above two dynamic equations can be subtracted respectively:

$\mathrm{<span\; class="notranslate">\; J</span>}<span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; a\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

Since J, B, K _d and K _p are all positive numbers, it can be seen from the above equation that under the action of the algorithm of the present invention, the angular motion of the scanning mirror servo motor and the derotation mechanism servo motor satisfies: θ ₁ -aθ ₂ → 0 , then θ ₁ /θ ₂ →a. Therefore, for scanning derotation imaging systems with different moments of inertia and external disturbances such as different friction torques, the present invention can make the rotation angles of the scanning servo motor and the derotation servo motor coordinate in strict proportion without adding an additional mechanical transmission mechanism. Under the premise of the premise, the high-precision linkage between the two is realized by means of electricity. By adjusting the gain of the position controller under the four-channel bidirectional control, the adjustment of the linkage accuracy and convergence speed of the two can be realized.

和

提供给四通道双向控制器中的比例微分位置控制器C_p(s)。DSP计算出总的驱动电机转动的控制量，以PWM波的形式经过相互独立的功率放大电路作用在电机上，使电机产生运动所需的驱动力矩，驱动电机转动。将控制算法中所有的拉普拉斯算子用双线性变换s=(2z-1)/(T_sz+1)的方式变换为离散形式，其中T_s为采样周期。将离散传递函数改写为差分方程，则可通过在DSP中编程实现本发明提出的控制算法。Figure 3 is a hardware structure diagram; the hardware background of the algorithm operation is a scanning derotation system. The light beam is deflected by the 45° scanning mirror and enters the optical mirror group; the 45° scanning mirror is driven by a circular scanning mirror servo motor, and an angular rate gyro and a photoelectric encoder are installed on the scanning mirror servo motor shafting. In order to reduce the size of the imaging system, the light path folding mirror can also be used to fold the light path. The derotation prism or imaging component arranged in the optical path is driven by the servo motor of the derotation mechanism to rotate, so as to eliminate image rotation. An angular rate gyroscope and a photoelectric encoder are also installed on the shafting of the derotation mechanism servo motor. The implementation algorithm of this embodiment takes the DSP as the core, and utilizes the internal timer function of the DSP to make the algorithm run cyclically according to a certain period. Use the external interface photoelectric encoder and angular rate gyroscope of DSP. Measure the rotational angular position of the scanning servo motor and the servo motor of the derotation mechanism relative to the frame of the imaging device through the photoelectric encoder installed on the motor shaft, and obtain the angular position information θ ₁ and θ ₂ required in the algorithm; The high-precision angular rate gyro on the servo motor of the scanning mirror and the servo motor of the derotation mechanism measures the rotational angular velocity of the two sets of servo systems

and

Provided to the proportional-derivative position controller C _p (s) in the four-channel bidirectional controller. DSP calculates the total control amount of driving motor rotation, and acts on the motor in the form of PWM wave through mutually independent power amplifier circuits, so that the motor generates the driving torque required for motion and drives the motor to rotate. All Laplacian operators in the control algorithm are transformed into discrete forms by means of bilinear transformation s=(2z-1)/(T _s z+1), where T _s is the sampling period. Rewriting the discrete transfer function as a differential equation, the control algorithm proposed by the present invention can be realized by programming in DSP.

和

按照关于四通道双向控制算法的说明结合图1计算新的双向控制量u_b1和u_b2；接下来，将扫描镜伺服电机和消旋机构伺服电机的双向控制量与各自的单电机指令跟踪控制器输出值相加，转换为PWM波的形式从DSP输出给功率放大电路；若持续控制则从第一步重复循环，若需停止控制则将各变量值保持或清零，退出循环。Fig. 4 is the software flowchart of the control method described in the present embodiment; First obtain the scan mirror rotation command, read the measured value of the photoelectric encoder and the angular rate gyroscope, obtain the angular position of the scan mirror servo motor and the derotation mechanism servo motor , angular velocity information, assign values to each variable in the program; then enter the loop and start the algorithm program: calculate the output value of the single motor command tracking controller A according to the scanning mirror rotation command and the angular position information of the scanning mirror servo motor; according to the scanning mirror rotation command and the angular position information of the derotation mechanism servo motor to calculate the control amount of the single motor instruction tracking controller B; according to the measured angular position of the scanning mirror servo motor and the derotation mechanism servo motor, the two-way control calculated in the previous control cycle Calculate the output value of the equivalent torque estimator of the scanning mirror servo motor and the derotation mechanism servo motor by measuring u _b1 and u _b2 ; calculate the position information difference by using the readout value of the photoelectric encoder of the scanning mirror servo motor and the derotation mechanism servo motor aθ ₂ -θ ₁ and θ ₁ /a-θ ₂ ; use the scanning mirror and derotation mechanism angular rate gyro readout value to calculate the velocity information difference

and

Calculate the new bidirectional control quantities u _b1 and u _b2 according to the description of the four channel bidirectional control algorithm in combination with figure 1 ; next, combine the bidirectional control quantities of the scanning mirror servo motor and the derotation mechanism servo motor with the respective single motor command tracking control The output values of the converters are added together, converted into PWM waves and output from the DSP to the power amplifier circuit; if the control is continued, the cycle is repeated from the first step, and if the control needs to be stopped, the values of each variable are kept or cleared, and the cycle is exited.

The present invention realizes that the servo motor of the scanning mirror and the servo motor of the derotation mechanism strictly cooperate to rotate according to the rotation command of the scanning mirror without adding a mechanical transmission mechanism. The algorithm can be applied between the scanning mirror servo system and the derotation mechanism servo system, which are completely different in moment of inertia, friction moment, and external disturbance moment. The algorithm of the present invention can be realized based on DSP programming.

Claims (6)

1. one kind is used for the bidirection control method that scanning imaging system elimination picture revolves, comprise single motor controller for following command A, single motor controller for following command B, two equivalent moment estimators and four-way reversible controller, described single motor controller for following command A and single motor controller for following command B are respectively applied to scanning mirror servomotor and racemization mechanism servomotor to the tracking of instruction; Described equivalent moment estimator provides moment information for the calculating of four-way reversible controller; Described four-way reversible controller is used for coordinating the rotation of scanning mirror servomotor and racemization mechanism servomotor; It is characterized in that concrete grammar is:

Step 1, according to the scanning mirror rotation command, obtain the angle position information θ of scanning mirror servomotor respectively ₁And angular velocity information

And the angle position information θ of racemization mechanism servomotor ₂, angular velocity information

It is poor with the angle position information of scanning mirror servomotor then the angle position information of racemization mechanism servomotor to be multiply by behind the scale-up factor a, obtains position difference a θ ₂-θ ₁It is poor that scanning mirror servomotor angle position information be multiply by behind the scale-up factor 1/a with the angle position information of racemization mechanism servomotor, obtains position difference θ ₁/ a-θ ₂The angle speed information calculations velocity information of the angular velocity information of scanning mirror servomotor and racemization mechanism servomotor is poor

With

Step 2, single motor controller for following command A are poor according to the angle position information of scanning mirror rotation command and scanning mirror servomotor, obtain the instruction trace controlled quentity controlled variable u of scanning mirror servomotor _C1Single motor controller for following command B is poor according to the angle position information of described scanning mirror rotation command and the racemization mechanism servomotor that multiply by scale-up factor a, obtains the instruction trace controlled quentity controlled variable u of racemization mechanism servomotor _C2

The equivalent moment estimated value of step 3, calculating scanning mirror servomotor and racemization mechanism servomotor;

Detailed process is: the angle position information θ of the scanning mirror servomotor that step 1 is obtained ₁After standard electromotor inversion model in the equivalent moment estimator and the transport function of low-pass filter product, with the two-way controlled quentity controlled variable u of last one-period through the scanning mirror servomotor of low-pass filter _B1Subtract each other the difference of gained as the output valve of the equivalent moment estimator on the scanning mirror servomotor; The angle position information θ of the racemization mechanism servomotor that obtains according to step 1 ₂After standard electromotor inversion model in the equivalent moment estimator and the transport function of low-pass filter product, with the two-way controlled quentity controlled variable u of last one-period through the racemization mechanism servomotor of low-pass filter _B2Subtract each other the difference of gained as the output valve of the equivalent moment estimator on the racemization mechanism servomotor;

Step 4, the position difference a θ that step 1 is obtained ₂-θ ₁And θ ₁/ a-θ ₂The scanning mirror servomotor that obtains with step 3 and the equivalent moment estimated value of racemization mechanism servomotor recomputate the two-way controlled quentity controlled variable u of scanning mirror servomotor _B1Two-way controlled quentity controlled variable u with racemization mechanism servomotor _B2

The instruction trace controlled quentity controlled variable u of step 5, scanning mirror servomotor that step 2 is obtained _C1Instruction trace controlled quentity controlled variable u with racemization mechanism servomotor _C2The two-way controlled quentity controlled variable u of the scanning mirror servomotor that obtains with step 4 respectively _B1Two-way controlled quentity controlled variable u with racemization mechanism servomotor _B2Stack, the output valve after the stack acts on the corresponding motor.

2. according to claim 1ly a kind ofly eliminate the bidirection control method that picture revolves for scanning imaging system, it is characterized in that the two-way controlled quentity controlled variable u of described scanning mirror servomotor _B1Two-way controlled quentity controlled variable u with racemization mechanism servomotor _B2Computation process be: the position difference a θ that step 1 is obtained ₂-θ ₁Poor with velocity information

Calculate controlled quentity controlled variable through a positioner in the four-way reversible controller, described controlled quentity controlled variable again with the racemization mechanism servomotor that multiply by scale-up factor a on the addition of equivalent moment estimator output valve; Obtain the two-way controlled quentity controlled variable u of scanning mirror servomotor _B1The two-way controlled quentity controlled variable u of described racemization mechanism servomotor _B2Acquisition process be: the position difference θ that step 1 is obtained ₁/ a-θ ₂Poor with velocity information

Calculate controlled quentity controlled variable through the another location controller in the four-way reversible controller, described controlled quentity controlled variable again with the scanning mirror servomotor that multiply by scale-up factor 1/a on the addition of equivalent moment estimator output valve, obtain the two-way controlled quentity controlled variable u of racemization mechanism servomotor _B2

3. according to claim 1ly a kind ofly eliminate the bidirection control method that picture revolves for scanning imaging system, it is characterized in that, when step 3 described one-period of lasting is first performance period, pass through the two-way controlled quentity controlled variable u of the scanning mirror servomotor of low-pass filter _B1, with the two-way controlled quentity controlled variable u of the racemization mechanism servomotor that passes through low-pass filter _B2Value be initial value.

4. the bidirection control method that described elimination looks like to revolve according to claim 1 is characterized in that: described single motor controller for following command A and single motor controller for following command B employing lead-lag corrective network.

5. the bidirection control method that described elimination looks like to revolve according to claim 1 is characterized in that: the positioner under the described four-way reversible controller is proportion differential control.

6. the bidirection control method that described elimination looks like to revolve according to claim 1, it is characterized in that: the structure of the equivalent moment estimator on the equivalent moment estimator on the described scanning mirror servomotor and the racemization mechanism servomotor is identical, and accepted standard motor inversion model is Js in the described equivalent moment estimator ²+ Bs, wherein J is that standard electromotor equivalence inertia, B are the standard electromotor equivalent damping, s is Laplace operator; Described low-pass filter is g ²/ (s ²+ 2gs+g ²), g is for adjusting the parameter of low pass filter cutoff frequency.

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