CN1845031A - Combined feedback-controlled vibration compensation system based on accelerometer - Google Patents

Abstract

Composite feedback control vibration compensation system based on accelerometer, it relates to the field of satellite optical communication technology, it avoids the terminal antenna pointing error caused by the vibration of the satellite platform, and solves the problem of limited detection field of view of the existing vibration compensation system . The X-axis accelerometer (3-1), the Y-axis accelerometer (3-2) and the Z-axis accelerometer (3-3) of the present invention are respectively fixed on the three space axes of the satellite platform and are used to measure the A spatial axial acceleration change; a part of the signal light output by the signal light generator (4) is beam-expanded by the optical antenna (1) and sent to the target terminal, and the other part is imaged on the CCD detector (7), controlled by the precision aiming mirror The device (5) controls the deflection of the precision aiming mirror (2) according to the information obtained by the three accelerometers and the information obtained by (7), thereby compensating the influence of more than 50% of the vibration of the satellite platform. The invention uses the accelerometer as the vibration detection element, improves the sampling rate, and does not have the problem of limited field of view.

Description

Composite Feedback Control Vibration Compensation System Based on Accelerometer

technical field

The invention relates to the technical field of satellite optical communication.

Background technique

The satellite optical communication terminal is carried by the satellite platform, and the vibration of the satellite platform will cause the terminal antenna to deviate, causing the signal light sent by the terminal to deviate from the target optical communication terminal (the ground terminal or the on-board terminal with which the link is established). This situation will attenuate the signal optical power that can be received by the target terminal, and in severe cases, it will cause the interruption of the satellite laser communication link. Therefore, it is one of the key problems in the research of satellite optical communication technology to propose an effective compensation method for satellite platform vibration. At present, there is a vibration compensation system based on the compound feedback control of the CCD detector. It uses the area array CCD detector as the vibration detection element of the satellite platform, which has the disadvantages of limited detection field of view and low sampling rate.

Contents of the invention

In order to avoid the terminal antenna pointing error caused by the vibration of the satellite platform and solve the problem of limited detection field of view of the existing vibration compensation system, the present invention provides a compound feedback control vibration compensation system based on an accelerometer.

The compensation system of the present invention includes an optical antenna and a signal light generator on a satellite platform, and the compensation system also includes a precision aiming mirror, a fine aiming mirror controller, a CCD detector, an imaging lens group, a beam splitter, and an X-axis accelerometer , Y-axis accelerometer and Z-axis accelerometer, the X-axis accelerometer, Y-axis accelerometer and Z-axis accelerometer are respectively fixed on the three spatial axes of the satellite platform and used to measure the acceleration changes of the satellite platform along the three spatial axes , the data output ends of the X-axis accelerometer, the Y-axis accelerometer and the Z-axis accelerometer are respectively connected to the three data input ends of the precision aiming mirror controller; the fine aiming mirror is composed of a total reflection mirror and a motion actuator, and the motion actuator uses To control the deflection of the total reflection mirror, the signal light output by the signal light generator passes through the total reflection mirror of the precision aiming mirror to change the optical path and then enters the light input end of the beam splitter, and part of the signal light output by the signal light generator is reflected by the beam splitter After that, it is incident on the optical input end of the secondary mirror of the optical antenna, and the signal light is transmitted to the target terminal after being expanded by the primary mirror of the optical antenna, and another part of the signal light output by the signal light generator is transmitted by the light splitter and then input to the The optical input end of the imaging lens group, the focused light beam is obtained at the optical output end of the imaging lens group and imaged on the CCD detector, and the output end of the CCD detector is connected to the image signal input end of the precision aiming mirror controller.

Working principle: When the satellite optical communication terminal transmits signal light to the target terminal according to the predicted direction, the vibration of the satellite platform will change the emission direction of the signal light, thus deviating from the predicted direction, and the vibration of the satellite platform needs to be compensated . The compensation system of the present invention first uses three accelerometers to measure the three spatial axial movements of the satellite platform to obtain the vibration amplitude and direction of the satellite platform, and then uses the deflection of the precision aiming mirror to control the emission direction of the signal light, so that The deflection of the precision aiming mirror cancels out the vibration of the satellite platform, so that the emission direction of the signal light is consistent with the predicted direction. The invention also utilizes the CCD detector to provide feedback information for the deflection of the precision aiming mirror, so as to ensure that the fine aiming mirror can be positioned accurately. The accelerometer installed on the satellite platform detects the change of the vibration acceleration of the platform, and calculates the rotation angle θ _h of the platform relative to the direction of the optical axis of the optical communication terminal, and the rotation angle θ _v of the direction of the pitch axis. Assuming that the magnification of the terminal optical antenna is ρ, the fine aiming mirror driver will use θh _{and θv} as input commands to control the fine aiming mirror to rotate ρ· _θh in the direction of the azimuth axis and ρ· _θv in the direction of the pitch axis, so that the terminal The output signal light still exits along the predicted direction, offsetting the influence of platform vibration. The CCD detector detects whether the rotation angle of the fine aiming mirror meets the requirements of the control command, calculates the difference with ρ·θ _h , ρ·θ _v , and inputs the difference to the fine aiming mirror controller to perform feedback closed-loop control on the fine aiming mirror, Improve precision aiming mirror angle control accuracy.

Effects of the invention: The present invention uses an accelerometer as a vibration detection element, so that the compensation system of the present invention has high sampling rate, high precision, small volume, low power consumption, and is convenient for space-borne, and adopts the method of mechanical vibration measurement, and there is no visual area affected limit problem. The compensation system of the invention detects the vibration of the satellite platform in real time, and can effectively compensate more than 50% of the influence caused by the vibration of the satellite platform.

Description of drawings

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

Detailed ways

Referring to Fig. 1, the compensation system of the present embodiment consists of an optical antenna 1, a signal light generator 4, a precision aiming mirror 2, a fine aiming mirror controller 5, a CCD detector 7, an imaging lens group 8, and a light splitter on a satellite platform. Sheet 6, X-axis accelerometer 3-1, Y-axis accelerometer 3-2 and Z-axis accelerometer 3-3, X-axis accelerometer 3-1, Y-axis accelerometer 3-2 and Z-axis accelerometer 3- 3 are respectively fixed on the three spatial axes of the satellite platform and used to measure the acceleration changes of the satellite platform along the three spatial axes, the X-axis accelerometer 3-1, the Y-axis accelerometer 3-2 and the Z-axis accelerometer 3-3 The data output ends of the precision aiming mirror controller 5 are respectively connected to the three data input ends; the fine aiming mirror 2 is composed of a total reflection mirror 2-1 and a motion actuator 2-2, and the motion actuator 2-2 is used to control the total reflection The mirror 2-1 deflects, and the signal light output by the signal light generator 4 passes through the total reflection mirror 2-1 of the precision aiming mirror 2 to change the optical path and then enters the light input end of the beam splitter 6, and a part of the output of the signal light generator 4 The signal light is incident on the light input end of the secondary mirror 1-1 of the optical antenna 1 after being reflected by the beam splitter 6, and the signal light is transmitted to the target terminal after being expanded by the primary mirror 1-2 of the optical antenna 1, and the signal light Another part of the signal light output by the generator 4 is transmitted through the beam splitter 6 and then input to the light input end of the imaging lens group 8, and the focused light beam is obtained at the light output end of the imaging lens group 8 and imaged on the CCD detector 7, and the CCD detector The output end of 7 is connected to the image signal input end of the precision aiming mirror controller 5 .

The optical antenna 1 uses a Cassegrain telescope with a diameter of 100 mm and a magnification of 20 times as the terminal optical antenna. Described CCD detector 7 selects the MTV-1801 area-array CCD video camera that Taiwan Mintong Company produces for use, and its main parameters are: spectral response range is 400nm～1100nm, pixel number is 795 (H) * 596 (V), image The element size is 10μrad, the horizontal frequency is 15625Hz, the vertical frequency is 50Hz, the resolution is 600TVL (line), the detection sensitivity is 0.021x (lux), the signal-to-noise ratio is greater than 46dB, the working temperature is -10℃～50℃, and the power supply is DC12V (2W). The pixel spacing of the CCD detector 7 determines the angular vibration detection accuracy of the satellite platform, the pixel determines the amplitude range of its detection angular vibration, and the spectral response range determines the application frequency band of the vibration compensation system. Grasping the above principles can be determined as required Model of CCD detector 7. The focal length of the imaging lens group 8 is 50mm. The central wavelength of the signal light generator 4 is 800 nm, and the beam divergence angle is 600 μrad. The X-axis accelerometer 3-1, Y-axis accelerometer 3-2 and Z-axis accelerometer 3-3 all use the CX3-2A linear accelerometer developed by the 26th Research Institute of China Electronics Technology Group Corporation.

The fine aiming mirror 2 and the fine aiming mirror controller 5 are integrated together, and the MPT-2JRL001 piezoelectric deflection mirror and its driver developed by Harbin Institute of Technology Boshi Precision Measurement and Control Co., Ltd. are selected. The deflection range of this deflection mirror is ±250μrad, and the frequency The frequency is 1kHz, the diameter of the reflecting surface is 40mm, and the deflection accuracy is 2μrad (estimated according to the feedback value of the displacement sensor). The workbench body of this deflection mirror is made of super duralumin LC4; the bottom surface of the platform is bonded with a K9 glass substrate reflector, that is, the total reflection mirror 2-1; Two deflection axes, two pieces of German PI piezoelectric ceramics (P841.20 type) are respectively fixed on these two deflection axes. The resulting deflection is independent of each other, and can be converted into the deflection angle of the mirror by calculating the displacement of the piezoelectric ceramics at their respective positions.

Claims (1)

1, combined feedback-controlled vibration compensation system based on accelerometer, described bucking-out system comprises optical antenna (1) and the flashlight generator (4) that is on the satellite platform, it is characterized in that described bucking-out system comprises that also essence takes aim at mirror (2), essence is taken aim at mirror controller (5), ccd detector (7), imaging lens group (8), light splitting piece (6), X-axis accelerometer (3-1), Y-axis accelerometer (3-2) and Z axis accelerometer (3-3), X-axis accelerometer (3-1), Y-axis accelerometer (3-2) and Z axis accelerometer (3-3) be separately fixed on three spatial axes of satellite platform and be used for the instrumented satellite platform along three spatial axes to acceleration change, X-axis accelerometer (3-1), the data output end of Y-axis accelerometer (3-2) and Z axis accelerometer (3-3) is connected three data input ends that essence is taken aim at mirror controller (5) respectively; Essence is taken aim at mirror (2) and is made of completely reflecting mirror (2-1) and movement executing mechanism (2-2), movement executing mechanism (2-2) is used to control completely reflecting mirror (2-1) deflection, the completely reflecting mirror (2-1) that the flashlight of flashlight generator (4) output is taken aim at mirror (2) by essence changes the light input end that incides light splitting piece (6) after the light path, a part of flashlight of described flashlight generator (4) output incides the light input end of the secondary mirror (1-1) of optical antenna (1) after light splitting piece (6) reflection, and be transmitted into target terminal behind primary mirror (1-2) the expansion bundle of this flashlight by optical antenna (1), another part flashlight of described flashlight generator (4) output is input to the light input end of imaging lens group (8) after light splitting piece (6) transmission, light output end in imaging lens group (8) obtains focused beam and goes up imaging at ccd detector (7), and the output terminal of ccd detector (7) connects the picture signal input end that essence is taken aim at mirror controller (5).