Aerospace remote sensing linear form amplitude-frequency detection and self-adaptive flutter suppression system and simulation system

Abstract

The invention relates to a space remote sensing linear form amplitude-frequency detection and self-adaptive flutter suppression system and a simulation system, and belongs to the technical field of spacecraft micro-vibration suppression. The space remote sensing linear form amplitude-frequency detection and self-adaptive flutter suppression system comprises a self-adaptive flutter suppression system and a form amplitude-frequency detection system; the TDI-CCD camera is installed on the self-adaptive flutter suppression system, the TDI-CCD camera images a target, the form amplitude-frequency detection system calculates flutter amplitude-frequency information according to a target image, calculates a negative stiffness value required by the self-adaptive vibration isolation system according to the flutter amplitude-frequency information and outputs a control signal corresponding to the negative stiffness value to the motor, the motor drives the eccentric wheel to rotate, and the self-adaptive vibration isolation system is driven by the eccentric wheel to rotate. Therefore, the inclination angle of the inclined spring is adjusted, and the self-adaptive flutter suppression system is in a quasi-zero stiffness interval. According to the invention, self-adaptive closed-loop control of flutter suppression is realized by utilizing direct image feedback, an additional sensor is not needed, and the method has the advantages of high universality, high adaptability and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of spacecraft micro-vibration suppression, and in particular to a space remote sensing linear mode amplitude-frequency detection and adaptive chattering suppression method and system. BACKGROUND

[0002] TDI-CCD cameras are widely used in military, mapping and other fields of earth observation due to their high signal-to-noise ratio and high dynamic range imaging characteristics in low light environments. However, due to factors such as periodic motion of attitude control components, the satellite platform will produce small amplitude and high frequency attitude vibration, resulting in imaging distortion and misalignment. In addition, with the development of commercial satellites, the requirement for lightweight satellites is becoming higher and higher, which leads to a decrease in the structural vibration resistance of the satellite. At the same time, the increase in on-orbit missions also brings more chattering, which is extremely difficult to suppress and easily coupled with the satellite itself modal, making the imaging performance of the optical load decline, and making the imaging environment become more severe. This causes the images obtained by the TDI-CCD camera to be distorted. Therefore, detecting and suppressing the influence of chattering on images is the key to ensuring high-quality imaging of TDI-CCD cameras. The existing chattering suppression system relies on a dedicated attitude sensor to measure the platform chattering, which has poor system versatility due to cost and structural limitations, making it difficult to popularize, and the system proposed in the present patent can well solve these problems. SUMMARY

[0003] The present application provides a space remote sensing linear mode amplitude-frequency detection and adaptive chattering suppression method and system to solve the problem of chattering suppression in the field of satellite on-orbit micro-vibration.

[0004] To solve the above technical problems, the technical scheme of the present application is as follows:

[0005] The space remote sensing linear mode amplitude-frequency detection and adaptive chattering suppression system comprises:

[0006] The adaptive chattering suppression system has a TDI-CCD camera mounted thereon and is used to isolate and transmit the chattering to the TDI-CCD camera under the driving of a motor, and comprises a support, a bearing plate, a vertical spring and two negative stiffness adjustment mechanisms connected between the support and the bearing plate and having the same structure. The two ends of the vertical spring are connected with the bearing plate and the support respectively. The two negative stiffness adjustment mechanisms are symmetrically arranged on the two sides of the vertical spring. Each negative stiffness adjustment mechanism comprises an inclined spring, an eccentric wheel, a cam and a vertical guide rail fixed on the support. One end of the inclined spring is connected with the bearing plate, and the other end is connected with the cam. The motor drives the eccentric wheel to rotate, and the eccentric wheel drives the cam to move along the vertical guide rail to adjust the inclination angle of the inclined spring. The TDI-CCD camera is fixed on the bearing plate.

[0007] A modal frequency detection system electrically connected with the TDI-CCD camera is used to acquire a target image collected by the TDI-CCD camera, and after image preprocessing is performed on the target image, the shake frequency information of the TDI-CCD camera is inverted and transmitted, and a negative stiffness value required by the adaptive shake suppression system is calculated according to the shake frequency information, and a corresponding control signal is output to the motor to drive the eccentric wheel to rotate, so that the tilt angle of the tilt spring is adjusted to an angle value corresponding to the negative stiffness value, and the adaptive shake suppression system is in a quasi-zero stiffness interval.

[0008] The combination of the space remote sensing linear modal frequency detection and adaptive shake suppression system and the image processing method is used for extracting shake information, and the shake detection and compensation based on digital image processing do not depend on special high-precision ground control data and other special high-frequency sensors, and have better applicability and universality. By adjusting the negative stiffness value in the adaptive shake suppression system, suppression of different amplitude excitation sources can be realized. In the system, the positive stiffness of the adaptive shake suppression system remains unchanged, the negative stiffness required by the adaptive shake suppression system is calculated through the shake frequency detected by the modal frequency detection system, the overall stiffness of the adaptive shake suppression system is ensured to be in a quasi-zero stiffness interval, and then the image after vibration isolation is subjected to frequency analysis by the modal frequency detection system to determine whether the adaptive shake suppression system plays a vibration isolation role, so that adaptive closed-loop control of the system is realized, the imaging quality of the TDI-CCD camera in a micro-vibration environment is effectively improved, and the system has the advantages of good vibration isolation effect, strong universality, strong adaptability, and no need for other additional sensors.

[0009] The application further provides a space remote sensing linear modal frequency detection and adaptive shake suppression simulation system, which comprises the suppression system and further comprises:

[0010] A medium-low-high omnidirectional vibration table, on which the adaptive shake suppression system is installed, is used for providing vibration with adjustable frequency for the adaptive shake suppression system.

[0011] A frequency-adjustable vibration table controller connected with the medium-low-high omnidirectional vibration table is used for setting the vibration frequency of the medium-low-high omnidirectional vibration table.

[0012] A dynamic target is used for providing an imaging target for the TDI-CCD camera.

[0013] The simulation system utilizes the medium-low-high omnidirectional vibration table to provide wide amplitude and multi-frequency excitation which can be freely matched, and makes the TDI-CCD camera image the dynamic target, so as to simulate the on-orbit push-broom imaging of the TDI-CCD camera; the amplitude and frequency of the vibration which the camera is subjected to in real time are determined by analyzing the offset of the pixel centroid in the target image, the negative stiffness required by the adaptive jitter suppression system is calculated, and the rotating angle of the eccentric wheel and the torque required to be output by the motor are obtained; the motor drives the eccentric wheel to rotate, the angle of the inclined spring is adjusted, the adaptive regulation and control of quasi-zero stiffness are realized, and the system has the advantages of complete function, lifelike simulation, strong verification capability and the like, and provides technical support for verifying the performance of the jitter suppression system itself. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 FIG. 1 is a structural schematic diagram of an adaptive jitter suppression system in one embodiment of the present application;

[0015] Figure 2 FIG. 2 is a structural schematic diagram of a simulation system in one embodiment of the present application;

[0016] Figure 3 FIG. 3 is a working flowchart of the simulation system shown in FIG. 2. Figure 2

[0017] BRIEF DESCRIPTION OF REFERENCE NUMERALS:

[0018] 1. Medium-low-high omnidirectional vibration table

[0019] 2. Amplitude-frequency tunable vibration table controller

[0020] 3. Adaptive jitter suppression system; 3-1, support; 3-2, bearing plate; 3-3, vertical spring; 3-4, inclined spring; 3-5, eccentric wheel; 3-6, cam; 3-7, vertical guide rail

[0021] 4. TDI-CCD camera

[0022] 5. Dynamic target

[0023] 6. Morphology amplitude-frequency detection system

[0024] 7. Motor DETAILED DESCRIPTION

[0025] The technical solutions of the present application will be described in detail below with reference to the drawings and preferred embodiments.

[0026] Embodiment one

[0027] The embodiment discloses a space remote sensing linear morphology amplitude-frequency detection and adaptive jitter suppression system, which comprises an adaptive jitter suppression system 3, a morphology amplitude-frequency detection system 6 and a motor 7.

[0028] ​Specifically, the TDI-CCD camera 4 is installed on the adaptive shake suppression system 3, which can isolate the shake transmitted to the TDI-CCD camera 4 under the control of the motor 7. As shown in Figure 1 The adaptive shake suppression system 3 includes a bracket 3-1, a carrier plate 3-2, a vertical spring 3-3 and two negative stiffness adjustment mechanisms with the same structure. The two negative stiffness adjustment mechanisms are connected between the bottom of the bracket 3-1 and the carrier plate 3-2, the two ends of the vertical spring 3-3 are connected with the carrier plate 3-2 and the bottom of the bracket 3-1 respectively, and the two negative stiffness adjustment mechanisms are symmetrically arranged on the two sides of the vertical spring 3-3. Each negative stiffness adjustment mechanism includes an inclined spring 3-4, an eccentric wheel 3-5, a cam 3-6 and a vertical guide rail 3-7 fixed on the bracket 3-1, wherein one end of the inclined spring 3-4 is connected with the carrier plate 3-2, the other end is connected with the cam 3-6, and the length direction of the inclined spring 3-4 forms an angle with the horizontal direction, which is the inclination angle, denoted as α. The output shaft of the motor 7 is connected with the eccentric wheel 3-5 for driving the eccentric wheel 3-5 to rotate. The eccentric wheel 3-5 is in contact with the edge of the cam 3-6, and the cam 3-6 is located in the vertical guide rail 3-7, which gives the cam 3-6 a fixed movement direction, and the cam 3-6 can move up and down along the vertical guide rail 3-7. Under the drive of the motor 7, the eccentric wheel 3-5 pushes the cam 3-6 to move along the vertical guide rail 3-7 to adjust the inclination angle of the inclined spring 3-4.

[0029] The TDI-CCD camera 4 is fixed on the carrier plate 3-2 in the adaptive shake suppression system 3 and is electrically connected with the modal amplitude-frequency detection system 6. The TDI-CCD camera 4 images the target and inputs the collected target image to the modal amplitude-frequency detection system 6.

[0030] After the modal amplitude-frequency detection system 6 obtains the target image collected by the TDI-CCD camera 4, it first performs image preprocessing on the target image. After preprocessing, the following detection method is used to reverse the shake amplitude-frequency information transmitted to the TDI-CCD camera 4 to obtain the detection vibration curve, which specifically includes the following steps:

[0031] Extracting the gray maximum value point of each row of linear scenery in the preprocessed image as the feature point of the row;

[0032] Detecting the offset of each row of pixels of the linear scenery, i.e. calculating the offset of each row of feature points relative to the prior scenery feature points;

[0033] Discrete Fourier transform is performed on the offsets of all feature points to convert the time domain signal to the frequency domain to obtain the shake amplitude-frequency information transmitted to the TDI-CCD camera 4, i.e. the amplitude and frequency of the shake transmitted to the TDI-CCD camera 4.

[0034] The morphological amplitude-frequency detection system 6 calculates the negative stiffness value required by the adaptive chatter suppression system 3 according to the obtained chatter amplitude-frequency information, and outputs a control signal corresponding to the negative stiffness value to the motor 7. The motor 7 inputs a corresponding torque to the eccentric wheel 3-5 according to the control signal, drives the eccentric wheel 3-5 to rotate, and further drives the cam 3-6 to move up and down along the vertical guide rail 3-7, changes the inclination angle of the inclined spring 3-4 in the adaptive chatter suppression system 3, and adjusts the negative stiffness value of the adaptive chatter suppression system 3 to the calculated negative stiffness value, so that the adaptive chatter suppression system 3 is in the quasi-zero stiffness interval. Under the action of the morphological amplitude-frequency detection system 6, the adaptive chatter suppression system 3 can always be in the quasi-zero stiffness interval under the excitation of different amplitudes and frequencies.

[0035] In the embodiment, the TDI-CCD camera 4 and the morphological amplitude-frequency detection system 6, and the morphological amplitude-frequency detection system 6 and the motor 7 are connected by data transmission lines.

[0036] The main working process of the system of the embodiment is as follows:

[0037] The TDI-CCD camera 4 is fixed, and the TDI-CCD camera 4 images the target in the direction perpendicular to the track, and inputs the target image obtained by imaging into the morphological amplitude-frequency detection system 6.

[0038] The morphological amplitude-frequency detection system 6 uses the structural similarity index (Structural Similarity Index Measure, SSIM) as an image evaluation index to determine whether the target image meets the clear imaging requirement. The SSIM can comprehensively evaluate the similarity between images from the structure, brightness, contrast and other aspects of the image. The formula of the SSIM is:

[0039] (1)

[0040] Wherein, respectively represent two images; respectively represent the average gray scale of the corresponding image , which is used to estimate the brightness information of the image; respectively represent the variance of the corresponding image , which is used to estimate the contrast information of the image; represents the covariance of the image , which is used to estimate the structural similarity between the two images. All are constants, represents the dynamic range of the image pixel, . The value of the SSIM is between 1 and -1. Two images that are exactly the same have an SSIM equal to 1. In the embodiment, when the SSIM value is greater than or equal to 0.99, it is determined that the target is clearly imaged.

[0041] Specifically, the morphological amplitude-frequency detection system 6 compares the calculated SSIM value of the target image with a pre-set threshold value. If the SSIM value is greater than or equal to the threshold value, it is determined that the target image meets the clear imaging requirement, and the target image is directly output. Meanwhile, the detection vibration curve corresponding to the target image can also be output. If the SSIM value is less than the threshold value, it is determined that the target image does not meet the clear imaging requirement, and the adaptive vibration suppression system 3 starts to work. The TDI-CCD camera 4 collects the target image after vibration isolation and inputs it into the morphological amplitude-frequency detection system 6. The morphological amplitude-frequency detection system 6 performs image preprocessing on the target image, and inversely derives the amplitude-frequency information of the vibration suffered by the TDI-CCD camera 4 in the imaging process, i.e., the displacement response amplitude transmitted to the TDI-CCD camera 4. According to the inversely derived amplitude-frequency information, the negative stiffness value required by the adaptive vibration suppression system 3 can be calculated. Then, the tilt angle of the tilt spring 3-4 is calculated according to the negative stiffness value, and the angle of rotation of the eccentric wheel 3-5 is determined. The morphological amplitude-frequency detection system 6 outputs the negative stiffness value or the control signal corresponding to the tilt angle obtained according to the negative stiffness value to the motor 7.

[0042] The motor 7 drives the eccentric wheel 3-5 to rotate clockwise or counterclockwise, pushes the cam 3-6 to move up and down along the vertical guide rail 3-7, changes the tilt angle of the tilt spring 3-4 in the adaptive vibration suppression system 3, and thus changes the negative stiffness value of the adaptive vibration suppression system 3, so that the adaptive vibration suppression system 3 is in the quasi-zero stiffness interval, and plays a role in vibration isolation for the TDI-CCD camera 4.

[0043] The TDI-CCD camera 4 after vibration isolation images the target again, and inputs the target image after vibration isolation into the morphological amplitude-frequency detection system 6 again. The morphological amplitude-frequency detection system 6 performs image preprocessing on the target image after vibration isolation, obtains the amplitude-frequency information of the vibration suffered by the TDI-CCD camera 4 in the imaging process after the adaptive vibration suppression system 3 works, and judges again whether the clear imaging requirement is met. If the clear imaging requirement is met, the target image after vibration isolation is output. If not, the morphological amplitude-frequency detection system 6 performs image preprocessing and vibration amplitude-frequency information inversion on the target image after vibration isolation again, calculates the negative stiffness value according to the inversely derived vibration amplitude-frequency information, and outputs the corresponding control signal to the motor 7 to drive the eccentric wheel 3-5 to rotate and change the tilt angle of the tilt spring 3-4, until a clear target image is output.

[0044] The space remote sensing linear morphological amplitude-frequency detection and adaptive vibration suppression system in the initial moment of the embodiment is assumed to be in contact between the cam 3-6 at the bottom end of the tilt spring 3-4 and the eccentric wheel 3-5 as shown in FIG. 1. Figure 1When the TDI-CCD camera 4 is placed on the adaptive vibration suppression system 3, the tilt spring 3-4 is in a horizontal state, the dead load is completely supported by the vertical spring 3-3, the system evolves into a quasi-zero stiffness position, and the system is in a static equilibrium position at this time.

[0045] The bearing plate 3-2 is subjected to the gravity of the camera itself Under the action of the excitation source, at a certain moment, the adaptive vibration suppression system 3 generates a vertical displacement amount The relationship between the two can be expressed as:

[0046] (2)

[0047] wherein, is the original length of the tilt spring, is the height of the tilt spring in the vertical direction, represents the distance between the bottom end of the tilt spring and the bottom end of the vertical spring 3-3, represents the stiffness of the vertical spring 3-3, represents the stiffness of the tilt spring 3-4.

[0048] If y is defined as the displacement amount of the bearing plate 3-2 from the position that is, the static equilibrium position, in the vertical direction, then formula (2) can be converted to:

[0049] (3)

[0050] The above formula (3) representing the force-displacement relationship is dimensionless:

[0051] (4)

[0052] wherein, , , , , , With the change of the micro-vibration, the displacement amount is constantly changing, and the stiffness also changes accordingly.

[0053] According to the definition of stiffness, the above formula (4) is derived with respect to to obtain the dimensionless stiffness of the adaptive vibration suppression system 3:

[0054] (5)

[0055] Therefore, the stiffness can be changed by changing the size of .

[0056] Non-dimensional stiffness of the system at the static equilibrium position The ratio of the spring stiffness coefficients of the system zero stiffness condition is: .

[0057] The value of :

[0058] If , then The ratio of the spring stiffness coefficients of the system zero stiffness condition is .

[0059] The angle of the eccentric wheel needs to be rotated is obtained by the required negative stiffness value, so that The angle of the system in quasi-zero stiffness is calculated .

[0060] The motor 7 drives the eccentric wheel 3-5 to rotate to the static equilibrium position, and the eccentric wheel 3-5 rotates to drive the cam 3-6 to move along the vertical guide rail 3-7, so that the angle value of the inclined spring 3-4 in the adaptive chatter suppression system 3 is 48.2°, at this time the entire adaptive chatter suppression system 3 is in the quasi-zero stiffness interval, and plays a role in vibration isolation for the TDI-CCD camera 4, and the target image after vibration isolation is input into the shape amplitude frequency detection system 6, which detects the amplitude frequency of the target image, and realizes adaptive closed-loop control.

[0061] The space remote sensing linear shape amplitude frequency detection and adaptive chatter suppression system combined with the image processing method proposed in this embodiment extracts the chatter information, and the chatter detection and compensation based on digital image processing do not depend on special high-precision ground control data and installation of other special high-frequency sensors, and have better applicability and universality. By adjusting the negative stiffness value in the adaptive chatter suppression system, suppression of different amplitude excitation sources can be realized. The positive stiffness of the adaptive chatter suppression system in the system remains unchanged, the chatter amplitude frequency detected by the shape amplitude frequency detection system is calculated to obtain the required negative stiffness of the adaptive chatter suppression system, so that the overall stiffness of the adaptive chatter suppression system is in the quasi-zero stiffness interval, and then the shape amplitude frequency detection system analyzes the amplitude frequency of the imaging image after vibration isolation to determine whether the adaptive chatter suppression system plays a role in vibration isolation, realizes adaptive closed-loop control of the system, effectively improves the imaging quality of the TDI-CCD camera in a micro-vibration environment, and has the advantages of good vibration isolation effect, strong universality, strong adaptability, and no need for other additional sensors.

[0062] Example two

[0063] ​The embodiment discloses a simulation system for detecting amplitude-frequency of linear form of aerospace remote sensing and adaptively suppressing chatter, which comprises the system for detecting amplitude-frequency of linear form of aerospace remote sensing and adaptively suppressing chatter disclosed in the first embodiment, a low-mid-high omnidirectional vibration table 1, an amplitude-frequency adjustable vibration table controller 2 and a dynamic target 5.

[0064] Specifically, as shown in the figure, Figure 2 the amplitude-frequency adjustable vibration table controller 2 is connected with the low-mid-high omnidirectional vibration table 1, the amplitude-frequency adjustable vibration table controller 2 can generate a high-frequency vibration curve for setting the vibration amplitude-frequency of the low-mid-high omnidirectional vibration table 1, and the low-mid-high omnidirectional vibration table 1 is controlled by the amplitude-frequency adjustable vibration table controller 2 to vibrate with adjustable amplitude-frequency, thereby providing excitation for simulating the on-orbit operation of a camera.

[0065] The adaptive chatter suppression system 3 is installed on the low-mid-high omnidirectional vibration table 1 and can isolate the chatter of the low-mid-high omnidirectional vibration table 1 transmitted to the TDI-CCD camera 4 under the control of the motor 7. The structure of the adaptive chatter suppression system 3 is described in the first embodiment, which will not be repeated here.

[0066] The TDI-CCD camera 4 is fixed on the bearing plate 3-2 in the adaptive chatter suppression system 3, images the dynamic target 5, simulates the imaging of a target by a camera in orbit, and inputs the collected target image to the form amplitude-frequency detection system 6.

[0067] The form amplitude-frequency detection system 6 adopts the same processing method as the target image, performs image preprocessing on the target image, detects and inverts the chatter amplitude-frequency information, calculates the negative stiffness value required by the adaptive chatter suppression system 3 according to the inverted chatter amplitude-frequency information, and outputs the control signal corresponding to the negative stiffness value to the motor 7. The motor 7 inputs a corresponding torque to the eccentric wheel 3-5 according to the control signal, drives the eccentric wheel 3-5 to rotate, and further drives the cam 3-6 to move up and down along the vertical guide rail 3-7, changes the inclination angle of the inclined spring 3-4 in the adaptive chatter suppression system 3, adjusts the negative stiffness value of the adaptive chatter suppression system 3 to the calculated negative stiffness value, and makes the adaptive chatter suppression system 3 in the quasi-zero stiffness interval. Under the action of the form amplitude-frequency detection system 6, the adaptive chatter suppression system 3 can always be in the quasi-zero stiffness interval under the excitation of different amplitude-frequencies.

[0068] In the embodiment, the amplitude-frequency adjustable vibration table controller 2 and the low-mid-high omnidirectional vibration table 1 are connected by a cable.

[0069] The working principle of the simulation system of the embodiment is as follows:

[0070] The amplitude-frequency adjustable resonant vibration table controller 2 controls the output of the medium-low-high omnidirectional vibration table 1 to output wide-amplitude, multi-frequency, freely matchable excitation, simulating the flutter experienced by the TDI-CCD camera 4 when it is on track.

[0071] Keep the TDI-CCD camera 4 fixed so that the TDI-CCD camera 4 images the dynamic target 5, simulating the TDI-CCD camera 4 imaging the target in the vertical direction on the track, and inputting the target image obtained by imaging into the morphology amplitude and frequency detection system 6.

[0072] The morphological amplitude-frequency detection system 6 uses the structural similarity index (SSIM) as an image evaluation metric to determine whether the target image meets the requirements for clear imaging.

[0073] Specifically, the calculated SSIM value of the target image is compared with a pre-set threshold. If the SSIM value is greater than or equal to the threshold, the target image is determined to meet the clear imaging requirements, and the target image is directly output. Simultaneously, the corresponding detection vibration curve of the target image can also be output, such as... Figure 2 As shown; if the SSIM value is less than the threshold, it is determined that the target image does not meet the requirements for clear imaging, and the adaptive flutter suppression system 3 starts to work. The TDI-CCD camera 4 acquires the target image after vibration isolation and inputs it into the morphology amplitude-frequency detection system 6. The morphology amplitude-frequency detection system 6 performs image preprocessing on the target image and inverts the amplitude-frequency information of the flutter experienced by the TDI-CCD camera 4 during the imaging process, that is, obtains the displacement response amplitude value transmitted to the TDI-CCD camera 4. Based on the inverted amplitude-frequency information, the negative stiffness value required by the adaptive flutter suppression system 3 can be calculated. Then, based on the negative stiffness value, the tilt angle of the tilt spring 3-4 is calculated, and the rotation angle of the eccentric wheel 3-5 is determined. The morphology amplitude-frequency detection system 6 outputs the negative stiffness value or the control signal corresponding to the tilt angle obtained based on the negative stiffness value to the motor 7.

[0074] Motor 7 drives eccentric wheel 3-5 to rotate clockwise or counterclockwise, pushing cam 3-6 to move up and down along vertical guide rail 3-7, changing the tilt angle of tilt spring 3-4 in adaptive flutter suppression system 3, thereby changing the negative stiffness value of adaptive flutter suppression system 3, so that adaptive flutter suppression system 3 is in the quasi-zero stiffness range, which plays a vibration isolation role for TDI-CCD camera 4.

[0075] The TDI-CCD camera 4 after vibration isolation images the dynamic target 5 again and inputs the target image after vibration isolation into the form amplitude frequency detection system 6 again. The form amplitude frequency detection system 6 performs image preprocessing on the target image after vibration isolation to obtain the amplitude and frequency information of the vibration received by the TDI-CCD camera 4 during the imaging process after the adaptive flutter suppression system 3 is in operation. The form amplitude frequency detection system 6 judges again whether the amplitude and frequency information meets the clear imaging requirement. If yes, the target image after vibration isolation is output. If no, the form amplitude frequency detection system 6 performs image preprocessing and inversion of the amplitude and frequency information of the vibration again. The negative stiffness value is calculated according to the inverted amplitude and frequency information of the vibration, and the corresponding control signal is output to the motor 7 to drive the eccentric wheel 3-5 to rotate and change the tilt angle of the tilt spring 3-4 until the clear target image is output.

[0076] Optionally, the output frequency range of the medium-low-high omnidirectional vibration table 1 is 2Hz-1500Hz. The micro-vibration received by the TDI-CCD camera 4 during the target push-broom imaging in orbit is provided by the medium-low-high omnidirectional vibration table 1. The medium-low-high omnidirectional vibration table 1 outputs different excitation to simulate the changing micro-vibration received by the TDI-CCD camera 4 during the in-orbit operation.

[0077] The TDI-CCD camera 4 selects LBAS-U350-60C, and the resolution is 2592x2048.

[0078] The width of the dynamic target 5 is 500mmx800mm.

[0079] During the integral imaging process of the TDI-CCD camera 4, the image formed without the influence of micro-vibration has clear edges and high imaging quality, and the naked eye can clearly see the picture edges. When a certain amplitude and vibration frequency are added, the image formed by the integral imaging of the TDI-CCD camera 4 has blurred edges, and the naked eye cannot clearly identify the edges.

[0080] The adaptive flutter suppression system 3 and the TDI-CCD camera 4 are sequentially installed on the medium-low-high omnidirectional vibration table 1, and the TDI-CCD camera 4 is connected with the form amplitude frequency detection system 6 through a data transmission line.

[0081] The TDI-CCD camera 4 images the dynamic target 5 under a certain amplitude and vibration frequency, and inputs the target image into the form amplitude frequency detection system 6. The form amplitude frequency detection system 6 performs image preprocessing on the target image and identifies the linear scene in the image. The gray maximum value point of each row of linear scene is extracted as the feature point of the row, the offset of each row of feature points of the linear scene relative to the prior scene feature points is calculated, and the amplitude and frequency of the platform vibration transmitted to the TDI-CCD camera 4 are inverted.

[0082] If the target image does not meet the clear imaging requirement, it indicates that the TDI-CCD camera 4 is subjected to the jitter transmitted by the medium-low-high omnidirectional vibration table 1 to the TDI-CCD camera 4 during the imaging push-broom process, and the TDI-CCD camera 4 needs to be subjected to the vibration isolation process.

[0083] The amplitude and frequency of the jitter transmitted by the medium-low-high omnidirectional vibration table 1 to the TDI-CCD camera 4 are obtained from the morphology amplitude-frequency detection system 6, and the negative stiffness value required by the adaptive jitter suppression system 3 under the amplitude-frequency vibration is calculated according to the extracted frequency and amplitude.

[0084] In order to objectively show the vibration isolation effect, the image evaluation index such as the structural similarity index can be used to evaluate the vibration isolation effect. The SSIM value of the image before vibration isolation is 0.9682, and the SSIM value of the image after vibration isolation is 0.9984, indicating that the adaptive jitter suppression system 3 has good vibration isolation effect.

[0085] The vibration characteristics of the medium-low-high omnidirectional vibration table 1 are continuously changed to generate different vibration amplitude-frequency signals, the TDI-CCD camera 4 continues to scan and image the dynamic target 5 under the changed amplitude-frequency, the morphology amplitude-frequency detection system 6 pre-processes the target image to obtain the new amplitude and frequency of the platform jitter transmitted to the TDI-CCD camera 4 under the changed state, and the negative stiffness value required by the adaptive jitter suppression system 3 under different vibration characteristics is calculated; the motor 7 drives the eccentric wheel 3-5 to rotate to change the angle of the inclined spring 3-4, so that the adaptive jitter suppression system 3 is always in the quasi-zero stiffness interval, and the real-time vibration isolation of the TDI-CCD camera 4 is realized under the condition of changing the amplitude-frequency.

[0086] As shown in Figure 3 The working process of the simulation system of the embodiment includes the following steps:

[0087] Step one: set the vibration amplitude-frequency of the medium-low-high omnidirectional vibration table 1 through the amplitude-frequency adjustable vibration table controller 2, so that the medium-low-high omnidirectional vibration table 1 generates amplitude-frequency adjustable vibration to simulate the jitter received by the TDI-CCD camera 4 during the on-orbit operation of the TDI-CCD camera 4;

[0088] Step two: image the dynamic target 5 by using the TDI-CCD camera 4 installed on the adaptive jitter suppression system 3, obtain the target image, and input the target image to the morphology amplitude-frequency detection system 6;

[0089] Step three: after the morphology amplitude-frequency detection system 6 pre-processes the target image, the jitter amplitude-frequency information transmitted to the TDI-CCD camera 4 is inverted;

[0090] Further, the morphological amplitude-frequency detection system 6 adopts the following detection method to inverse the jitter amplitude-frequency information transmitted to the TDI-CCD camera 4 to obtain a detection vibration curve, and the detection method specifically includes the following steps:

[0091] Extracting the gray maximum value points of each linear scene in the preprocessed image as the feature points of the row;

[0092] Detecting the offset of each row of pixels of the linear scene, that is, calculating the offset of each row of feature points relative to the prior scene feature points;

[0093] Discrete Fourier transform is performed on the offset of all feature points to convert the time domain signal to the frequency domain to obtain the jitter amplitude-frequency information transmitted to the TDI-CCD camera 4, that is, the amplitude and frequency of the jitter transmitted to the TDI-CCD camera 4.

[0094] Step four: After the morphological amplitude-frequency detection system 6 performs image preprocessing on the target image, the image evaluation index is calculated, and it is judged whether the value of the image evaluation index is greater than or equal to the threshold value. If yes, step seven is executed, otherwise, step five is executed;

[0095] Step five: The morphological amplitude-frequency detection system 6 calculates the negative stiffness value required by the adaptive jitter suppression system 3 according to the jitter amplitude-frequency information, and outputs the corresponding control signal to the motor 7; wherein the adaptive jitter suppression system 3 is used to isolate the jitter transmitted by the middle-low-high omnidirectional vibration table 1 to the TDI-CCD camera 4 under the driving of the motor 7, including a support 3-1, a bearing plate 3-2, a vertical spring 3-3, and two negative stiffness adjustment mechanisms connected between the support 3-1 and the bearing plate 3-2 and having the same structure. The two ends of the vertical spring 3-3 are respectively connected with the bearing plate 3-2 and the support 3-1. The two negative stiffness adjustment mechanisms are symmetrically arranged on both sides of the vertical spring 3-3. Each negative stiffness adjustment mechanism includes an inclined spring 3-4, an eccentric wheel 3-5, a cam 3-6, and a vertical guide rail 3-7 fixed on the support 3-1. One end of the inclined spring 3-4 is connected with the bearing plate 3-2, and the other end is connected with the cam 3-6. The motor 7 is connected with the morphological amplitude-frequency detection system 6 through a data transmission line;

[0096] Step six: The motor 7 drives the eccentric wheel 3-5 to rotate according to the control signal, and the eccentric wheel 3-5 drives the cam 3-6 to move along the vertical guide rail 3-7 to adjust the inclination angle of the inclined spring 3-4 to the angle value corresponding to the negative stiffness value, so that the adaptive jitter suppression system 3 is in the quasi-zero stiffness interval, and then returns to step two, and the TDI-CCD camera 4 reimages the dynamic target 5;

[0097] Step seven: It is judged that the isolated target image meets the clear imaging requirement, and the target image is directly output.

[0098] The simulation system for space remote sensing linear mode amplitude-frequency detection and adaptive chattering suppression provided by the embodiment utilizes a medium-low-high omnidirectional vibration table to provide excitation with wide amplitude and multiple frequencies, and makes a TDI-CCD camera image a dynamic target, so as to simulate the on-orbit push-broom imaging of the TDI-CCD camera; the amplitude-frequency of the vibration received by the camera in real time is determined by analyzing the offset of the pixel centroid in the target image, the negative stiffness required by the adaptive chattering suppression system is calculated, and the rotating angle of the eccentric wheel and the torque required to be output by the motor are obtained; the motor drives the eccentric wheel to rotate, the angle of the tilting spring is adjusted, the adaptive regulation and control of quasi-zero stiffness are realized, and the simulation system has the advantages of complete functions, lifelike simulation, strong verification capability and the like, and provides technical support for verifying the performance of the chattering suppression system itself.

[0099] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered that they are within the scope of the present disclosure.

[0100] The above-described embodiments only express several implementation manners of the present application, the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent right of the present application. It should be pointed out that, for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent right of the present application should be subject to the appended claims.

Claims

1. A spaceborne remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system, characterized in that, include: An adaptive flutter suppression system (3), on which a TDI-CCD camera (4) is mounted, is used to isolate flutter transmitted to the TDI-CCD camera (4) under the drive of a motor (7). It includes a bracket (3-1), a support plate (3-2), a vertical spring (3-3), and two identical negative stiffness adjustment mechanisms connected between the bracket (3-1) and the support plate (3-2). The two ends of the vertical spring (3-3) are respectively connected to the support plate (3-2) and the bracket (3-1). The two negative stiffness adjustment mechanisms are symmetrically arranged on both sides of the vertical spring (3-3). Each negative stiffness adjustment mechanism… The stiffness adjustment mechanism includes a tilting spring (3-4), an eccentric wheel (3-5), a cam (3-6), and a vertical guide rail (3-7) fixed on the bracket (3-1). One end of the tilting spring (3-4) is connected to the bearing plate (3-2), and the other end is connected to the cam (3-6). The motor (7) drives the eccentric wheel (3-5) to rotate, and the eccentric wheel (3-5) pushes the cam (3-6) to move along the vertical guide rail (3-7) to adjust the tilt angle of the tilting spring (3-4). The TDI-CCD camera (4) is fixed on the bearing plate (3-2). The morphological amplitude-frequency detection system (6), which is electrically connected to the TDI-CCD camera (4), is used to acquire the target image collected by the TDI-CCD camera (4), perform image preprocessing on the target image, invert the flutter amplitude-frequency information transmitted to the TDI-CCD camera (4), calculate the negative stiffness value required by the adaptive flutter suppression system (3) based on the flutter amplitude-frequency information, and output the corresponding control signal to the motor (7) to drive the eccentric wheel (3-5) to rotate, adjust the tilt angle of the tilt spring (3-4) to the angle value corresponding to the negative stiffness value, so that the adaptive flutter suppression system (3) is in the quasi-zero stiffness range.

2. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 1, characterized in that, The process by which the morphological amplitude-frequency detection system (6) inverts the jitter amplitude-frequency information transmitted to the TDI-CCD camera (4) includes the following steps: Extract the gray-level maxima of each row of linear objects in the preprocessed image as the feature points of that row; Calculate the offset of each row of feature points relative to prior scene feature points; The offset of all feature points is subjected to discrete Fourier transform to convert the time domain signal to the frequency domain, thereby obtaining the amplitude and frequency of the jitter transmitted to the TDI-CCD camera (4).

3. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 1, characterized in that, The morphological amplitude-frequency detection system (6) calculates the image evaluation index of the target image acquired by the TDI-CCD camera (4) after vibration isolation, and determines whether the value of the image evaluation index is greater than or equal to the threshold. If so, the target image after vibration isolation is directly output; if not, the negative stiffness value is calculated based on the flutter amplitude-frequency information obtained by inversion, and the corresponding control signal is output to the motor (7).

4. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 3, characterized in that, The image evaluation metric is the structural similarity index.

5. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 3 or 4, characterized in that, The threshold is 0.

99.

6. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 1, characterized in that, The dimensionless stiffness of the adaptive flutter suppression system (3) The formula is: （5）； in, , This indicates the distance between the bottom end of the inclined spring (3-4) and the bottom end of the vertical spring (3-3). This is the original length of the inclined spring (3-4); y represents the vertical displacement of the bearing plate (3-2) from its static equilibrium position; , This indicates the stiffness of the tilting spring (3-4). This indicates the stiffness of the vertical spring (3-3).

7. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 6, characterized in that, The ratio of the spring stiffness coefficients of the adaptive flutter suppression system (3) under zero stiffness condition is: .

8. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 7, characterized in that, Let the ratio of the spring stiffness coefficients of the adaptive flutter suppression system (3) under zero stiffness condition be... Solve And then according to The tilt angle of the tilting spring (3-4) when the adaptive flutter suppression system (3) is in near-zero stiffness is calculated.

9. The aerospace remote sensing linear morphology amplitude-frequency detection and adaptive flutter suppression system according to claim 1, characterized in that, The morphological amplitude and frequency detection system (6) is electrically connected to the TDI-CCD camera (4) and the motor (7) via data transmission lines.

10. A simulation system for linear morphology amplitude-frequency detection and adaptive flutter suppression in aerospace remote sensing, characterized in that, The system includes the suppression system as described in any one of claims 1 to 9, and further includes: A medium-low-high all-around vibration table (1) is provided with an adaptive flutter suppression system (3) installed on it to provide amplitude-frequency adjustable vibration for the adaptive flutter suppression system (3); An amplitude-frequency adjustable resonant vibration table controller (2) connected to the medium-low-high omnidirectional vibration table (1) is used to set the vibration amplitude and frequency of the medium-low-high omnidirectional vibration table (1); A dynamic target (5) is used to provide an imaging target for the TDI-CCD camera (4).

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