A two-dimensional fast mirror support structure

Abstract

This invention discloses a two-dimensional fast-reflecting mirror support structure, including a mounting base and multiple sets of cross-shaped spring assemblies disposed on the mounting base. Each set of cross-shaped spring assemblies includes two flat springs arranged in a cross shape, with the deflection axes of the flat springs collinear. The multiple sets of cross-shaped spring assemblies are arranged axially, and the cross points of each set of springs coincide, forming a common pivoting elastic support structure. This invention achieves wear-free and backlash-free two-axis deflection by using elastic deformation drive, solving the core problems of accuracy attenuation and high maintenance costs of traditional fast-reflecting mirrors. It breaks through the limitation of the deflection angle of traditional fast-reflecting mirrors, achieving a large angle deflection of ±7°, while improving the rotation accuracy to within 0.1 arcseconds.

Description

Technical Field

[0001] This invention relates to the field of communication equipment technology, and in particular to a two-dimensional fast-reflecting mirror support structure. Background Technology

[0002] Currently, in modern optical communication technology systems, two-dimensional fast reflectors (FDRs) are core components for achieving beam acquisition, aiming, and tracking (ATP) functions, and are widely used in inter-satellite communication, satellite-to-ground communication, and lidar. Traditional FDRs often employ mechanical bearings, gear drives, or hydraulic actuation, with their deflection angle typically limited to ±5°. They also suffer from inherent drawbacks such as mechanical wear, clearance errors, and large size. For example, a certain type of traditional mechanical bearing FDR experienced a decrease in rotational accuracy from an initial 1.2 arcseconds to 3.5 arcseconds after three years of on-orbit operation, and the communication link bit error rate increased to 1×10⁻⁻⁻⁴. 6 The existing fast-reflecting mirrors cannot meet the demands of Tb-level high-speed transmission. With the dense deployment of low-Earth orbit satellites and the increase in communication rates towards the Tb level, the performance of existing fast-reflecting mirrors can no longer meet the requirements of next-generation spaceborne laser communication systems for large-angle deflection, high-precision control, miniaturized integration, and long-life operation. Therefore, developing two-dimensional fast-reflecting mirror technology with large-angle deflection capability, high-precision control performance, and a compact structure has become a key breakthrough in promoting the upgrade of spaceborne laser communication technology. Summary of the Invention

[0003] The purpose of this invention is to provide a two-dimensional fast-reflecting mirror support structure that can meet the requirements of large-angle deflection capability and high-precision control performance of two-dimensional fast-reflecting mirrors.

[0004] The technical solution adopted in this invention is as follows:

[0005] A two-dimensional fast-reflecting mirror support structure includes a mounting base and multiple sets of cross-shaped spring assemblies disposed on the mounting base; each set of cross-shaped spring assemblies includes two flat springs arranged in a cross shape, and the deflection axes of the flat springs are collinear.

[0006] Multiple sets of the cross-shaped spring assemblies are arranged axially, and the cross points of each set of springs coincide, forming a common pivoting elastic support structure.

[0007] The number of sets of the flat reed is three.

[0008] The flat spring sheet has a thickness of 0.2 mm, a width of 5 mm, and a length of 20 mm.

[0009] The flat spring is made of TC4 titanium alloy, and the mounting base is made of LY12 aluminum alloy.

[0010] The TC4 titanium alloy material undergoes solution treatment at a temperature of 930°C for 1 hour, followed by air cooling.

[0011] A two-dimensional fast-reflecting mirror includes the aforementioned two-dimensional fast-reflecting mirror support structure, as well as a reflector, a driver, and an angle sensor;

[0012] The reflector is fixed to the mounting base of the two-dimensional fast-reflecting mirror support structure;

[0013] The driver is connected to the spring of the two-dimensional fast-reflecting mirror support structure and is used to drive the spring to bend and deform, thereby causing the mirror to deflect around the rotation center.

[0014] The angle sensor is used to detect the deflection angle of the reflector in real time.

[0015] The driver is a piezoelectric ceramic driver or a voice coil motor; the angle sensor is a laser interferometer.

[0016] A laser welding method for processing the aforementioned two-dimensional fast-reflection mirror support structure, used to weld TC4 titanium alloy springs and LY12 aluminum alloy mounting bases together, includes the following steps:

[0017] Pre-treatment is performed on the welding surfaces of the flat spring and the mounting base;

[0018] Assemble and position the flat spring sheet with the mounting base;

[0019] Laser welding was used for welding, with the following parameters: laser power 175W, welding speed 4mm / s, defocusing amount +2mm, and shielding gas flow rate 12.5L / min.

[0020] This invention, through innovative two-dimensional fast-reflecting mirror support structure design and laser welding technology, breaks through the limitations of traditional fast-reflecting mirror deflection angles, achieving a large-angle deflection of ±7° while improving rotation accuracy to within 0.1 arcseconds. This technology abandons the contact-type motion method of traditional mechanical bearings, employing elastic deformation drive to achieve wear-free and backlash-free two-axis deflection, solving the core problems of accuracy degradation and high maintenance costs inherent in traditional fast-reflecting mirrors. ANSYS finite element simulation analysis shows that the flexible components of this technology exhibit uniform stress distribution within the ±7° deflection range, with a maximum stress value of 230 MPa, far below the yield strength of elastic materials (300 MPa), ensuring the long-term reliability of the structure. Furthermore, through structural parameter optimization, this technology achieves a "rigid-flexible" design goal, significantly improving the system's vibration and shock resistance and environmental adaptability while ensuring large-angle deflection, providing a new technological paradigm for the application of flexible support technology in high-precision optomechanical systems. Meanwhile, the technology's compatibility and customizability enable it to meet diverse needs ranging from micro communication terminals (weight <100g) to large satellite payloads (weight >500g), propelling space communication into the era of high-speed transmission. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

[0023] Figure 2 This is a three-dimensional schematic diagram of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 and 2As shown, the two-dimensional fast-reflecting mirror support structure of the present invention includes a mounting base 6 and multiple sets of cross-shaped spring assemblies 2 disposed on the mounting base 6. Each set of cross-shaped spring assemblies includes two flat springs arranged in a cross shape, with the deflection axes of the springs being collinear; the multiple sets of cross-shaped spring assemblies 2 are arranged axially, and the cross points of each set of springs coincide, forming a co-pivot elastic support structure. This structure is the core component of the co-pivot flexible support technology. Its core design concept is to achieve rotational motion through the bending deformation of the elastic springs, with the rotation center precisely coinciding with the cross point, ensuring the coaxiality and consistency of the two-axis deflection.

[0026] To achieve large-angle deflection, this invention improves the traditional two-dimensional fast-reflecting mirror support structure by employing a design combining multiple sets of cross-shaped springs. By increasing the number of springs and optimizing their dimensional parameters, the deformation capability of the flexible components is effectively enhanced, extending the deflection angle of the fast-reflecting mirror from the traditional ±5° to ±7°. Simultaneously, the combination of multiple spring sets also strengthens the rigidity and stability of the structure, ensuring the system's anti-interference capability while achieving large-angle deflection.

[0027] In this embodiment, the number of reeds is three. Through comparative tests, the structural stiffness of the three-reed combination is 2.3 times higher than that of a single reed, and the vibration and impact resistance is increased by 40%.

[0028] The reed has a thickness of 0.2 mm, a width of 5 mm, and a length of 20 mm. These parameters were obtained through finite element simulation and orthogonal experimental optimization. Specifically, a two-dimensional finite element model of the fast-reflecting mirror support structure was established using ANSYS Workbench software. With deflection angle, rotation accuracy, and structural stiffness as optimization objectives, a multi-objective genetic algorithm was used to optimize parameters such as the thickness, width, length, and number of reed groups. Simulation results showed that: reed thickness is positively correlated with structural stiffness; for every 0.05 mm increase in thickness, structural stiffness increases by 15%-20%, but the deflection angle decreases by 8%-10%; reed length is positively correlated with deflection angle; for every 5 mm increase in length, the deflection angle increases by 12%-15%, but the natural frequency of the structure decreases by 5%-8%; the number of reed groups is positively correlated with structural stiffness and stability; increasing the number of groups from 2 to 3 increases structural stiffness by 60% and anti-interference capability by 40%, but increases volume by 15% and weight by 10%. Considering all performance indicators, the parameters for this embodiment were finally determined. With these parameters, the structure can deflect an angle of ±7.05°, with rotation accuracy controlled within 0.08 arcseconds. The structure has a stiffness of 12 N·m / rad and a natural frequency of 250 Hz, meeting the requirements for strong vibration and shock during satellite launch (natural frequency ≥200 Hz). This achieves a harmonious balance between large-angle deflection and high-precision control.

[0029] The spring is made of TC4 titanium alloy, and the mounting base is made of LY12 aluminum alloy. TC4 titanium alloy has a low elastic modulus (110 GPa), which is beneficial for large-angle deflection; it also has a long fatigue life (12.8 × 10⁻⁶). 6 (times), capable of meeting the long-term on-orbit operation requirements of satellites (service life ≥ 15 years, cumulative deformation times ≥ 10 times), and able to meet the long-term on-orbit operation requirements of satellites (service life ≥ 15 years, cumulative deformation times ≥ 10 times). 7 With a density of only 4.51 g / cm³, it facilitates lightweight design; it has a wide operating temperature range (-250~+500℃), adapting to extreme temperature environments in space. To further improve material properties, TC4 titanium alloy underwent solution treatment at 930℃ for 1 hour, followed by air cooling. After treatment, the yield strength increased to 920 MPa, and the fatigue life increased to 14.2 × 10⁻⁶ MPa. 7 The mounting base is made of LY12 aluminum alloy, which has low density (2.7g / cm³), high strength (yield strength 270MPa), good rigidity (elastic modulus 70GPa), good welding compatibility with TC4 titanium alloy, excellent machinability, and can achieve high-precision dimensional machining (dimensional tolerance ≤ ±0.01mm).

[0030] A laser welding method for processing the two-dimensional fast-reflection mirror support structure as described in Example 1, used to weld TC4 titanium alloy springs and LY12 aluminum alloy mounting bases together, includes the following steps:

[0031] (1) Pre-treat the welding surfaces of the spring and the mounting base to remove oil stains, oxide layers, etc.; (2) Assemble and position the spring and the mounting base to ensure that the cross points coincide; (3) Weld using laser welding process.

[0032] To achieve optimal welding quality, this invention optimized the laser welding process parameters through orthogonal experiments. Key parameters affecting laser welding performance include laser power (P), welding speed (v), defocusing amount (f), and shielding gas flow rate (Q). Each parameter was set to three levels, and L9 (3) experiments were conducted. 4Orthogonal experiments were conducted. Weld penetration depth, weld width, thermal deformation, and weld strength were used as evaluation indicators, and a comprehensive scoring method (with weights of 0.3, 0.2, 0.3, and 0.2, respectively) was employed to evaluate weld quality. Experimental results showed that the influence of each factor on weld quality, from largest to smallest, was: laser power > welding speed > defocusing amount > shielding gas flow rate. The optimal combination of process parameters was: laser power 175W, welding speed 4mm / s, defocusing amount +2mm, and shielding gas flow rate 12.5L / min. Under this parameter combination, the weld penetration depth was 0.8mm, the weld width was 1.2mm, the thermal deformation was 3.2μm, and the weld strength was 235MPa, meeting the design requirements. Microscopic observation of the welded two-dimensional fast-reflecting mirror support structure revealed a smooth weld, free of defects such as porosity and cracks, and with fine and uniform grains, ensuring the dimensional accuracy and mechanical properties of the structure.

[0033] A two-dimensional fast-reflecting mirror includes a support structure, a mirror (not shown), a driver 3, and an angle sensor. The mirror is fixed to a mounting base 5 of the support structure via a mirror mount 1. The driver is connected to a spring on the support structure and drives the spring to bend and deform, causing the mirror to deflect around its rotation center. The angle sensor detects the deflection angle of the mirror in real time. The driver 3 is a piezoelectric ceramic driver or a voice coil motor; the angle sensor is a laser interferometer.

[0034] In actual operation, when the fast reflector is driven by the driving torque of the drive mechanism (such as piezoelectric ceramics or voice coil motors), the cross-shaped elastic springs will undergo symmetrical bending deformation, causing the reflector to deflect around the center of rotation. Due to the symmetrical design of the springs and their uniform radial distribution, the deflection motion has good linearity and repeatability, with a linearity error of ≤0.5%, effectively ensuring the control accuracy of the fast reflector.

[0035] To achieve high-precision and fast-response control of the fast-reflecting mirror, this invention also designs a control system based on a "host computer + slave computer" architecture and adopts a composite control algorithm of "PID control + feedforward control".

[0036] The control system mainly consists of four parts: an upper-level monitoring module, a lower-level control module, a drive module, and a sensor feedback module. The upper-level monitoring module, developed using LabVIEW software, is used for parameter setting (target deflection angle, control gain, etc.), real-time data acquisition and display (actual deflection angle, response time, etc.), fault alarms, and recording. The lower-level control module uses an STM32H743 microcontroller as its core, with a main frequency of up to 480MHz, to achieve real-time operation of the control algorithm and data processing. The drive module uses a high-precision piezoelectric ceramic driver (model: P-885.91, PI GmbH, Germany), with a resolution of 0.1nm and an output thrust range of 0-100N. The sensor feedback module uses a Renishaw XL-80 laser interferometer as the angle sensor, with a measurement accuracy of 0.01 arcseconds and a sampling frequency of 1kHz, providing real-time feedback of the actual deflection angle of the fast-reflecting mirror to form a closed-loop control.

[0037] In control algorithms, PID control is used to suppress system disturbances and improve control accuracy; feedforward control is used to compensate for system dynamic lag and improve response speed. The mathematical model of the PID control algorithm is:

[0038] The mathematical model of the PID control algorithm is shown in the following equation:

[0039]

[0040] in, To control the output, For deviation signal ( (where de(t) is the target deflection angle and de(t) is the actual deflection angle). This is the proportionality coefficient. The integral coefficient is... Here are the differential coefficients. Using the Ziegler-Nichols tuning method, combined with actual system testing, the final determined PID parameters are: = 8.5, = 0.3, = 0.5. Under this parameter configuration, the system's steady-state error is ≤0.02 arcseconds, and the overshoot is ≤5%, meeting the requirements for high-precision control.

[0041] The feedforward control algorithm outputs the control quantity in advance based on the first and second derivatives of the target deflection angle. Its mathematical model is as follows:

[0042] in, For feedforward control output, For the target angular velocity, For the target angular acceleration, For velocity feedforward coefficient, This represents the acceleration feedforward coefficient.

[0043] Through system identification, determine = 0.002, =0.0001. After introducing feedforward control, the system's step response time was shortened from 3.8ms with pure PID control to 2.5ms, improving the response speed by 34.2% and effectively compensating for the system's dynamic lag.

[0044] Beneficial effects

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) Performance improvement: The two-dimensional fast mirror based on the common pivot flexible support technology is significantly better than the traditional fast mirror technology in terms of deflection angle (±7.05°), rotation accuracy (within 0.08 arcseconds), dynamic response speed (step response time 2.5ms), volume, weight, vibration and shock resistance, fatigue life and radiation resistance. It has an overwhelming advantage in high-precision control and miniaturized integration, which can fully meet the performance requirements of the new generation of spaceborne laser communication systems.

[0047] (2) Reduced size, power consumption and weight: Traditional fast-reflective mirror technology is large and heavy, and the power consumption is usually higher than 5W. This invention has the advantages of extreme miniaturization and lightweight. After packaging, it is only the size of a coin, and the power consumption can be as low as 2W or less.

[0048] (3) Improved dynamic performance: Traditional technologies have a slow response (low frequency for voice coil motors) and nonlinear problems such as hysteresis and creep (for piezoelectric ceramics). The technology of this invention has an extremely fast response (step response can reach 0.41 milliseconds), extremely high linearity (>99.95%), no hysteresis or fatigue characteristics, and can achieve a "true" fast response, providing a guarantee for high-speed and high-precision ATP (capture, track, aim).

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0051] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0052] Note that the above description is merely a preferred embodiment and application of the technical principles of the present invention. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the specific embodiments described herein, and may include many other effective embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A two-dimensional fast-reflection mirror support structure, characterized in that, Includes a mounting base and multiple sets of cross-shaped spring assemblies disposed on the mounting base; Each of the cross-shaped reed assemblies includes two flat reeds arranged in a cross shape, the deflection axes of the flat reeds being collinear; Multiple sets of the cross-shaped spring assemblies are arranged axially, and the cross points of each set of springs coincide, forming a common pivoting elastic support structure.

2. The two-dimensional fast-reflection mirror support structure according to claim 1, characterized in that, The number of sets of the flat reed is three.

3. The two-dimensional fast-reflection mirror support structure according to claim 1, characterized in that, The flat spring sheet has a thickness of 0.2 mm, a width of 5 mm, and a length of 20 mm.

4. The two-dimensional fast-reflection mirror support structure according to any one of claims 3, characterized in that, The flat spring is made of TC4 titanium alloy, and the mounting base is made of LY12 aluminum alloy.

5. The two-dimensional fast-reflection mirror support structure according to claim 4, characterized in that, The TC4 titanium alloy material undergoes solution treatment at a temperature of 930°C for 1 hour, followed by air cooling.

6. A two-dimensional fast-reflection mirror, characterized in that, Includes a two-dimensional fast-reflecting mirror support structure as described in any one of claims 1-5, as well as a reflector, a driver, and an angle sensor; The reflector is fixed to the mounting base of the two-dimensional fast-reflecting mirror support structure; The driver is connected to the spring of the two-dimensional fast-reflecting mirror support structure and is used to drive the spring to bend and deform, thereby causing the mirror to deflect around the rotation center. The angle sensor is used to detect the deflection angle of the reflector in real time.

7. The two-dimensional fast-reflection mirror according to claim 6, characterized in that, The driver is a piezoelectric ceramic driver or a voice coil motor; the angle sensor is a laser interferometer.

8. A laser welding method for processing a two-dimensional fast-reflection mirror support structure as described in any one of claims 1 to 5, characterized in that, The steps for welding TC4 titanium alloy springs to LY12 aluminum alloy mounting bases are as follows: Pre-treatment is performed on the welding surfaces of the flat spring and the mounting base; Assemble and position the flat spring sheet with the mounting base; Laser welding was used for welding, with the following parameters: laser power 175W, welding speed 4mm / s, defocusing amount +2mm, and shielding gas flow rate 12.5L / min.

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