CN107153382B - Flexible hinged plate vibration control device and method based on binocular vision measurement - Google Patents

Abstract

The invention discloses a vibration control device and method for a flexible hinged board based on binocular vision measurement. The device includes a flexible hinged board body, a vibration detection part, a drive control part, a signal processing module and a computer; the flexible hinged board body consists of two The flexible plates of the same material are connected together by hinges; the vibration detection part includes multiple acceleration sensors, two industrial cameras and a slide projector; the drive control part includes multiple piezoelectric film drivers; the vibration detection part detects the flexible hinge plate body The vibration signal is input into the computer through the signal processing module, and the computer runs the corresponding active control algorithm, which is output to the drive control part through the signal processing module to suppress the vibration of the flexible hinged plate body. The vibration control device realizes the complete non-contact measurement of the vibration of the hinged plate by using the method of projecting marker points on a slide projector and detecting with a camera, so that the measurement result is more accurate.

Description

Vibration control device and method for flexible hinged plate based on binocular vision measurement

technical field

The invention relates to the field of positioning and vibration control of flexible structures, in particular to a vibration control device and method for a flexible hinged plate based on binocular vision measurement.

Background technique

Flexibility and enlargement are an important development trend of various aerospace structures. Light structure means that the weight of payload can be increased, and large structure makes the design and manufacture of spacecraft more flexible. However, due to the low stiffness and high flexibility of large-scale flexible structures, when running in space without external resistance, they are very vulnerable to external excitations and produce long-lasting low-frequency and high-amplitude vibrations. Therefore, the vibration analysis and analysis of large-scale flexible structures Control studies are necessary.

In the existing technology, flexible board structures are usually used to simulate space sailboards, and sensors such as piezoelectric sheets, acceleration sensors, shape memory alloys, angular rate gyroscope sensors, and photoelectric position sensors are mainly used to realize the vibration of the flexible board structure. Measurement. However, the application of piezoelectric materials and shape memory alloys is limited due to factors such as their own strength, fatigue life and temperature resistance; acceleration sensors and angular rate gyroscope sensors are sensitive to noise and can only measure the displacement of a certain point on the object Information; the photoelectric position sensor has a small measurement range, complex structure, difficult operation, cumbersome calculation process and high cost.

In the research of vibration measurement and active control of large flexible structures, using binocular vision system to measure the vibration of structures has its unique advantages. Binocular vision measurement is a non-contact measurement that does not change the vibration characteristics of the structure, so the measurement results obtained are accurate. In binocular vision measurement, it is required to have mark points on the structure. In practice, the method of pasting mark points on the structure and projecting mark points on the structure is usually used. The practice of pasting mark points on the structure will affect the vibration of the structure to a certain extent, while the projection mark The point can realize the real non-contact measurement, but the vibration information of the projected point is used to replace the real vibration information of the plate, and the approximate method is adopted. Since the vibration of the plate is of small amplitude, it means that this approximate method is feasible.

The low-frequency bending vibration and torsional vibration of a large flexible structure such as a flexible plate are coupled together. By using a camera to monitor different marker points, the vibration information of different marker points can be obtained, thereby decoupling the vibration and obtaining the vibration of the plate respectively. Bending vibration information and torsional vibration information, the bending vibration information is used to drive the piezoelectric driver to suppress the bending vibration of the plate, and the torsional vibration information is used to drive the piezoelectric driver to suppress the torsional vibration of the plate.

Contents of the invention

The object of the present invention is to address the deficiencies of the prior art, and to provide a vibration control device for flexible hinged plates based on binocular vision measurement, so as to realize non-contact, real-time and accurate measurement of the vibration of flexible hinged plates, while taking into account the vibration information to replace the approximation of the real vibration information of the flexible board.

Another object of the present invention is to provide a vibration control method of a flexible hinged board based on binocular vision measurement.

The purpose of the present invention can be achieved through the following technical solutions:

A vibration control device for a flexible hinged board based on binocular vision measurement, comprising a flexible hinged board body, a vibration detection part, a drive control part, a signal processing module, and a computer; the flexible hinged board body is passed through by two flexible boards of the same material The hinges are connected together, and one end of the formed flexible hinged plate body is suspended and clamped on the support fixed on the horizontal test bench I through a mechanical clamping device. The flexible hinged plate body is perpendicular to the horizontal plane, and the other end is a free end; the vibration detection part Including the camera detection part and multiple acceleration sensors, the camera detection part includes two industrial cameras and a slide projector, the two industrial cameras are fixed on the horizontal experiment platform II through slide rails to form a binocular vision measurement system, and the slide projector is also placed in the horizontal experiment On stage II, the light spot is projected onto the flexible hinged board body, the lens planes of the two industrial cameras are parallel to the flexible hinged board body, and aligned with the light spot projected by the slide projector on the flexible hinged board body; multiple acceleration sensors are installed on the flexible hinged board The edge of the main body near the free end; the drive control part includes a plurality of piezoelectric actuators, and the multiple piezoelectric actuators are double-sidedly pasted on the flexible plate near the fixed end of the flexible hinged plate body; the vibration detection part detects that the flexible hinged plate body The vibration signal is input into the computer through the signal processing module, and the computer runs the corresponding active control algorithm, and then output to the drive control part through the signal processing module to suppress the vibration of the flexible hinged plate body.

Further, the signal processing module includes an adaptive amplifier, an acquisition control card, a terminal board and a voltage amplifier. The vibration detection part detects the vibration signal of the flexible hinged board body, and transmits it to the terminal board after being modulated by the adaptive amplifier, and then through the acquisition The A/D conversion module inside the control card converts the analog signal into a digital signal and then inputs it into the computer. The computer runs the corresponding active control algorithm, outputs the control signal through the acquisition control card, transmits it through the terminal board, and amplifies the signal through the voltage amplifier Finally, it is output to the drive control part to suppress the vibration of the flexible hinged plate body.

Furthermore, the quantity and specific sticking positions of the piezoelectric actuators can be designed according to the size and material of the flexible hinge plate body.

Further, the position of the light spot projected by the slide projector on the flexible hinged board body can be designed according to the vibration information of the flexible hinged board body that the measurer wants to obtain.

Further, the drive control part includes a plurality of piezoelectric actuators, of which four piezoelectric actuators are pasted on the front and back of the flexible hinged board body near the fixed end of the flexible board midline, two on each side, pasted symmetrically, and connected in parallel, Used to control the torsional vibration of the flexible board; among them, 8 pieces of piezoelectric actuators are pasted on the front and back of the flexible hinged board body near the fixed end of the flexible board on both sides of the center line, four pieces on each side, symmetrically pasted, connected in parallel, and used to control the flexible board In the middle of the width direction on the right side of the flexible plate near the fixed end, a piezoelectric driver is pasted as a bending vibration sensor.

Further, the vibration control device for flexible hinged panels based on binocular vision measurement can be used to simulate the vibration of solar panels in space. When there is no light source in the environment where the solar panels are located, use a slide projector to project marker points combined with a camera The way of detection is to obtain the vibration information of solar panels.

Another object of the present invention can be achieved through the following technical solutions:

A method for controlling vibration of a flexible hinged plate based on binocular vision measurement, said method comprising the following steps:

1. Turn on the slide projector to project the light spot of the mark point on the flexible hinged board body, use the industrial camera and acceleration sensor to detect the vibration of the flexible hinged board body, and obtain the corresponding vibration signal;

2. The vibration signal collected by the acceleration sensor in step 1 is modulated by the adaptive amplifier and then transmitted to the terminal board, and then the analog signal is converted into a digital signal by the A/D conversion module inside the acquisition control card and then input into the computer. Industrial camera The collected vibration signal is directly input into the computer;

3. The computer runs the corresponding active control algorithm, and the obtained vibration control signal is output through the D/A conversion module of the acquisition control card, transmitted through the information of the terminal board, and output to the drive control part after the signal is amplified by the voltage amplifier to suppress the flexibility. Vibration of the hinged plate body;

4. Change the control parameters, test repeatedly, obtain multiple test results, and obtain the vibration characteristics and control effects of the flexible hinged plate body.

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

1. The vibration control device of the flexible hinged plate based on binocular vision measurement of the present invention uses a slide projector to project marker points combined with camera detection to realize a completely non-contact measurement of the vibration of the hinged plate, since the measurement does not have any influence on the vibration characteristics of the plate , so the obtained measurement results are more accurate.

2. The vibration control device of the flexible hinged plate based on binocular vision measurement of the present invention uses a camera to monitor different projected marker points, and can obtain vibration information of different marker points, which can reflect the bending of the flexible plate Vibration information and torsional vibration information, thus realizing the vibration decoupling of the flexible board.

3. The present invention uses a slide projector to project light spots to obtain mark points on the board surface, which solves the vibration measurement problem of the hinged board in an environment without a light source.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of a vibration control device for a flexible hinged plate based on binocular vision measurement according to Embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of the flexible hinged board body in Embodiment 1 of the present invention.

Fig. 3 is a flow chart of calibration of light spots of marker points by an industrial camera in Embodiment 2 of the present invention.

Fig. 4 is a flow chart of the measurement method of the binocular vision measurement system composed of two industrial cameras in Embodiment 2 of the present invention.

Among them, 1-industrial camera, 2-acceleration sensor, 3-hinge, 4-piezoelectric driver, 5-slide projector.

Detailed ways

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1:

As shown in Figure 1, the present embodiment provides a vibration control device for a flexible hinged board based on binocular vision measurement, including a flexible hinged board body, a vibration detection part, a drive control part, a signal processing module, and a computer; the flexible hinged board The plate body is connected by two flexible plates of the same material through a hinge (3) (as shown in Figure 2). Above, the flexible hinged plate body is perpendicular to the horizontal plane, and the other end is a free end; the vibration detection part includes a camera detection part and a plurality of acceleration sensors (2), and the camera detection part includes two industrial cameras (1) and a slide projector (5 ), two industrial cameras (1) are fixed on the horizontal test bench Ⅱ through slide rails to form a binocular vision measurement system, and the slide projector (5) is also placed on the horizontal test bench Ⅱ to project the light spot onto the flexible hinged board body. The lens planes of the two industrial cameras (1) are parallel to the flexible hinged board body, aiming at the light spot projected by the slide projector (5) on the flexible hinged board body; two acceleration sensors (2) are installed on the edge of the flexible hinged board body near the free end The drive control part includes a plurality of piezoelectric actuators (4), of which four piezoelectric actuators (4) are pasted on the front and back of the flexible hinged plate body near the fixed end of the flexible plate midline, two on each side, symmetrical Paste, connected in parallel, used to control the torsional vibration of the flexible board; among them, 8 pieces of piezoelectric actuators (4) are pasted on the front and back of the flexible hinged board body near the fixed end of the flexible board on both sides of the center line, four pieces on each side, symmetrically pasted, Parallel connection is used to control the bending vibration of the flexible board. A piezoelectric driver (4) is attached to the middle position in the width direction on the right side of the flexible board near the fixed end as a bending vibration sensor; the vibration detection part detects the flexible hinged board body The vibration signal is input into the computer through the signal processing module, and the computer runs the corresponding active control algorithm, and then output to the drive control part through the signal processing module to suppress the vibration of the flexible hinged plate body.

Wherein, the signal processing module includes an adaptive amplifier, an acquisition control card, a terminal board and a voltage amplifier. The vibration detection part detects the vibration signal of the flexible hinged board body, and transmits it to the terminal board after being modulated by the adaptive amplifier, and then through the acquisition control The A/D conversion module inside the card converts the analog signal into a digital signal and then inputs it into the computer. The computer runs the corresponding active control algorithm, outputs the control signal through the acquisition control card, transmits it through the terminal board, and amplifies the signal through the voltage amplifier. Output to the drive control part to suppress the vibration of the flexible hinged plate body.

Further, the quantity and specific sticking positions of the piezoelectric sheet drivers (4) can be designed according to the size and material of the flexible hinge plate body. The light spot position projected by the slide projector (5) on the flexible hinged board body can be designed according to the vibration information of the flexible hinged board body that the measurer wants to obtain. The vibration control device for flexible hinged panels based on binocular vision measurement can be used to simulate the vibration of solar panels in space. In the absence of light sources in the environment where solar panels are located, use a slide projector (5) to project marker points in combination with a camera The way of detection is to obtain the vibration information of solar panels.

In this embodiment, the flexible board used is a thin board made of epoxy resin. The size of the first flexible board connected to the fixed end is 550mm×500mm×2mm, and the size of the second flexible board is 50mm×500mm×2mm. The modulus of elasticity of the epoxy resin is E _p =34.64Gpa, and the density is ρ=1840kg/m ³ . The industrial camera (1) selects the GIGE camera of model acA1600-60gc produced by Basler, Germany, adopts CMOS photosensitive chip, the highest frame rate is 60fps, and the resolution is 1600×1200; the lens of Ricoh Company is selected, and its model is FL-HC0614- 2M, the focal length is 6mm, and the size is Φ32mm×35.7mm. The slide rail is selected from MISUMI company and the model is SENA33H-400-V10-W70, and the length is 400mm. The slide projector (5) selects the 130af slide projector of the model E130 produced by Braun Company of Germany for use, and is equipped with a 24V/150W strong light lamp. The piezoelectric driver (4) is made of piezoelectric ceramic material, the geometric size is 45mm×15mm×1mm, it is pasted on the flexible board in a sheet form, the distance from the fixed end is 230mm or 20mm, and the distance from the upper and lower edges of the board is 45mm. The elastic modulus of the ceramic material is E _p =63Gpa, d31 =-166pm/V. The acceleration sensor (2) selects the capacitive sensor of model 8310B10 from Kistler Company, its nominal sensitivity is 200mv/g, and the measurement frequency range is 0-180Hz. The acquisition control card is the DMC-2x00 digital motion controller produced by the American GALIL company, which provides a standard PCI bus interface; the CPU model of the selected computer is core76650U2.2GHz, the memory is 4G, and there is a PCI-e slot in the motherboard, which can be installed for acquisition. control card. The voltage amplifier can be composed of parts such as APEX-PA241DW or APEX-PA240CX piezoelectric amplifier, and the magnification can reach 52 times, that is, -5V～+5V can be amplified to -260～+260V.

Example 2:

This embodiment provides a method for controlling the vibration of a flexible hinged plate based on binocular vision measurement, including the following steps:

1. Turn on the slide projector (5) to project the light spot of the mark point on the flexible hinged board body, use the industrial camera (1) and the acceleration sensor (2) to detect the vibration of the flexible hinged board body, and obtain the corresponding vibration signal;

In this step, the flow chart of the industrial camera (1) calibrating the light spot of the marker point is shown in Figure 3, including the following steps:

The first step, establish a coordinate system: take the midpoint O _w of the front surface of the second flexible board as the coordinate origin, establish the world coordinate system O _W -X _W Y _W Z _W ; use the optical center O _c of the camera as the origin, establish the camera Coordinate system O _c -X _c Y _c Z _c ; take the first pixel in the upper left corner of the image as the origin O ₀ to establish the image coordinate system O ₀ -UV; take the center point O ₁ of the image as the origin to establish the imaging plane coordinate system O ₁ -XY.

In the second step, the transformation between the coordinates of the world coordinate system and the coordinates of the camera coordinate system at any point in the space (such as point P) can be described by the rotation matrix R and the translation vector t:

Among them, (x _c y _c z _c ), (x _w y _w z _w ) are the coordinates of point P in the camera coordinate system and the world coordinate system, respectively. R is an orthogonal identity matrix, and t is a three-dimensional translation vector.

The third step, in this calibration, the model used by the camera is a pinhole model, so there is the following coordinate transformation in the imaging process:

Among them, (xy) is the coordinate of point P in the image, (x _c y _c z _c ) is the coordinate of the point in the camera coordinate system, and f is the focal length of the camera lens. The above formula is expressed in matrix form as:

Based on the above, the transformation relationship between the coordinates of the imaging plane coordinate system and the coordinates of the world coordinate system is obtained:

The fourth step, the origin _O0 of the image coordinate system is located at the first pixel in the upper left corner of the image plane, the U axis and the V axis are along the width and height directions of the image respectively, and the coordinate point (uv) represents the uth column and the first pixel in the image The pixels of row v. The intersection of the camera optical axis and the image plane is O ₁ (u ₀ v ₀ ), this point is the center of the image, with this point as the origin, the X-axis and Y-axis are along the width and height directions of the image, respectively, to establish the imaging plane coordinate system O ₁ -XY. Assuming that the physical dimensions of each pixel in the X-axis and Y-axis directions are dx and dy respectively, then any pixel on the image has the following relationship in the two coordinate systems:

Expressed in matrix form:

To sum up, the transformation relationship between the image coordinate system coordinates of any point P and the world coordinate system coordinates can be obtained:

u₀、v₀四个参数只与相机内部结构有关，称为相机内部参数；而矩阵R和向量t与相机的位置及姿态有关，而与相机结构无关，称为相机外部参数。确定相机内、外部参数的过程，就是相机标定。实验中相机标定方法采用基于棋盘格标定板的张正友标定法，即通过提取拍摄的黑白棋盘标定板图像的特征点的坐标，利用极大似然估计法解得相机模型的内、外参数，实际操作中可以使用opencv或者MATLAB标定工具箱。In the formula,

The four parameters u ₀ and v ₀ are only related to the internal structure of the camera, which are called internal camera parameters; while the matrix R and vector t are related to the position and attitude of the camera, but have nothing to do with the structure of the camera, they are called external camera parameters. The process of determining the internal and external parameters of the camera is camera calibration. In the experiment, the camera calibration method adopts the Zhang Zhengyou calibration method based on the checkerboard calibration board, that is, by extracting the coordinates of the feature points of the black-and-white checkerboard calibration board image, and using the maximum likelihood estimation method to solve the internal and external parameters of the camera model, the actual You can use opencv or MATLAB calibration toolbox during operation.

The flow chart of the measurement method of the binocular vision measurement system composed of two industrial cameras (1) is shown in Figure 4;

2. The vibration signal collected by the acceleration sensor (2) in step 1 is modulated by the adaptive amplifier and then transmitted to the terminal board, and then the analog signal is converted into a digital signal by the A/D conversion module inside the acquisition control card and then input into the computer , the vibration signal collected by the industrial camera (1) is directly input into the computer;

3. The computer runs the corresponding active control algorithm, and the obtained vibration control signal is output through the D/A conversion module of the acquisition control card, transmitted through the information of the terminal board, and output to the drive control part after the signal is amplified by the voltage amplifier to suppress the flexibility. Vibration of the hinged plate body;

4. Change the control parameters, test repeatedly, obtain multiple test results, and obtain the vibration characteristics and control effects of the flexible hinged plate body.

The above is only a preferred embodiment of the patent of the present invention, but the scope of protection of the patent of the present invention is not limited thereto. The equivalent replacement or change of the technical solution and its invention patent concept all belong to the protection scope of the invention patent.

Claims (5)

1. The utility model provides a flexible articulated slab vibration controlling means based on binocular vision is measured which characterized in that: the flexible hinged plate comprises a flexible hinged plate body, a vibration detection part, a driving control part, a signal processing module and a computer; the flexible hinged plate body is formed by connecting two flexible plates made of the same material together through a hinge, one end of the formed flexible hinged plate body is suspended and clamped on a support fixed on the horizontal experiment table I through a mechanical clamping device, the flexible hinged plate body is vertical to the horizontal plane, and the other end of the flexible hinged plate body is a free end; the vibration detection part comprises a camera detection part and a plurality of acceleration sensors, the camera detection part comprises two industrial cameras and a slide projector, the two industrial cameras are fixed on a horizontal experiment table II through slide rails to form a binocular vision measurement system, the slide projector is also arranged on the horizontal experiment table II and projects light spots onto the flexible hinged plate body, and the lens planes of the two industrial cameras are parallel to the flexible hinged plate body and align with the light spots projected on the flexible hinged plate body by the slide projector; a plurality of acceleration sensors are arranged at the edge of the flexible hinged plate body close to the free end; the drive control part comprises a plurality of piezoelectric sheet drivers, and the two sides of the piezoelectric sheet drivers are stuck on the flexible plate of the flexible hinge plate body close to the fixed end; the vibration detection part detects a vibration signal of the flexible hinged plate body, the vibration signal is input into a computer through the signal processing module, the computer runs a corresponding active control algorithm, and then the vibration signal is output to the driving control part through the signal processing module to inhibit the vibration of the flexible hinged plate body;

the signal processing module comprises an adaptive amplifier, an acquisition control card, a terminal board and a voltage amplifier, wherein a vibration detection part detects a vibration signal of the flexible hinged board body, the vibration signal is transmitted to the terminal board after being modulated by the adaptive amplifier, an analog signal is converted into a digital signal through an A/D conversion module in the acquisition control card and then is input into a computer, the computer runs a corresponding active control algorithm, the control signal is output through the acquisition control card, is transmitted through the terminal board, is output to a drive control part after being amplified by the voltage amplifier, and the vibration of the flexible hinged board body is inhibited;

the drive control part comprises a plurality of piezoelectric sheet drivers, wherein 4 piezoelectric sheet drivers are adhered to the front and back sides of the flexible plate body close to the center line of the fixed end of the flexible hinged plate body, and each two piezoelectric sheet drivers are symmetrically adhered and connected in parallel and are used for controlling the torsional vibration of the flexible plate; the 8 piezoelectric sheet drivers are adhered to the front and back sides of the flexible plate body close to the two sides of the center line of the flexible plate at the fixed end, and four piezoelectric sheet drivers are symmetrically adhered to each side and connected in parallel for controlling the bending vibration of the flexible plate; and a piezoelectric piece driver is also stuck at the middle position of the right side of the flexible plate close to the fixed end in the width direction and is used as a bending vibration sensor.

2. The binocular vision measurement-based flexible hinged plate vibration control device of claim 1, wherein: the number and the specific sticking position of the piezoelectric sheet drivers can be designed according to the size and the material of the flexible hinged plate body.

3. The binocular vision measurement-based vibration control device for the flexible hinged plate according to claim 1, wherein: the light spot position projected on the flexible hinge plate body by the slide projector can be designed according to the vibration information of the flexible hinge plate body, which is desired by a measurer.

4. The binocular vision measurement-based vibration control device for the flexible hinged plate according to claim 1, wherein: the flexible hinged plate vibration control device based on binocular vision measurement can be used for simulating the vibration condition of a solar panel in space, and under the condition that the environment where the solar panel is located has no light source, the vibration information of the solar panel is obtained by using a projector projection mark point and combining a camera detection mode.

5. A method of flexible hinge plate vibration control apparatus in accordance with claim 1, said method comprising the steps of:

1. opening a slide projector to project mark point light spots on the flexible hinged plate body, and detecting the vibration of the flexible hinged plate body by using an industrial camera and an acceleration sensor to obtain a corresponding vibration signal;

2. modulating a vibration signal acquired by the acceleration sensor in the first step through an adaptive amplifier and transmitting the modulated vibration signal to a terminal board, converting an analog signal into a digital signal through an A/D (analog/digital) conversion module in an acquisition control card and inputting the digital signal into a computer, and directly inputting the vibration signal acquired by the industrial camera into the computer;

3. the computer runs a corresponding active control algorithm, the obtained vibration control signal is output through the D/A conversion module of the acquisition control card, is transmitted through the information of the terminal board, is amplified by the voltage amplifier and then is output to the drive control part, and the vibration of the flexible hinge plate body is suppressed;

4. and changing control parameters, repeatedly testing, and obtaining a plurality of test results to obtain the vibration characteristic and the control effect of the flexible hinged plate body.

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