Satellite-borne antenna pointing mechanism and control method thereof

Abstract

The application discloses a kind of spaceborne antenna pointing mechanism and control method thereof, belong to spacecraft attitude control technical field, solve the problem of high cost, low control accuracy in prior art antenna pointing mechanism;Specifically including antenna double-axis pointing mechanism, the bottom of antenna double-axis pointing mechanism is fixed on antenna support;Antenna double-axis pointing mechanism top is equipped with antenna reflector;Locking release device connects antenna support and antenna double-axis pointing mechanism, satellite into orbit after locking release device removes the connection effect of both;Antenna double-axis pointing mechanism includes pitch data transmission mechanism and horizontal data transmission mechanism.In the application, through "output end full closed loop" measurement and "silent calibration", the pointing accuracy of spaceborne antenna pointing mechanism is improved from 1.8 ° order of magnitude of open-loop stepper motor to <±0.1 °;Long-term in "open-loop maintenance" mode when working, power consumption is much lower than continuous closed-loop operation servo system, especially suitable for higher power consumption small microsatellite.

Description

Technical Field

[0001] This invention relates to the field of spacecraft attitude control technology, and in particular to a spaceborne antenna pointing mechanism and its control method. Background Technology

[0002] With the rapid development of microsatellite technology, increasingly stringent requirements have been placed on the pointing accuracy, reliability, and cost control of spaceborne communication antennas. Currently, spaceborne antenna pointing mechanisms mainly employ two approaches.

[0003] The first approach is to use a brushless DC servo motor. This approach employs a configuration of "brushed-free DC motor (BLDC) + high-precision encoder + complex servo driver." While this approach offers excellent dynamic performance, it suffers from the following drawbacks: High cost: aerospace-grade BLDC motors, high-resolution encoders, and multi-loop servo drivers are expensive, contradicting the trend towards lower cost and mass production for small satellites. System complexity: The system requires simultaneous and stable control of the current loop, speed loop, and position loop, resulting in complex algorithms and long and challenging ground debugging and on-orbit verification cycles. High power consumption: even during the position holding phase, the motor needs continuous power to provide torque, leading to high overall power consumption.

[0004] The second approach is to use an open-loop stepper motor technology solution. To reduce costs, this solution typically employs an open-loop control method combining a stepper motor and a reducer. While this solution is simple to control, low-cost, and self-locking after power failure, its inherent limitations restrict its on-orbit application. For example: there is a risk of step loss; under complex load disturbances in the space environment (such as changes in mechanical friction and fluctuations in thermal drag torque), step loss is likely to occur, leading to accumulated positioning errors, which the system itself cannot detect or recover from. Absolute position loss is also a concern; after a power failure, the system cannot remember the antenna's absolute pointing angle, requiring a time-consuming and risky mechanical zero-finding operation upon power restoration, impacting the satellite's emergency response capabilities. Low-speed vibration is another issue; traditional full-step / half-step drive modes exhibit significant torque pulsation at low speeds, potentially causing micro-vibrations that affect platform stability and communication quality.

[0005] Therefore, there is an urgent need in this field for a spaceborne antenna pointing technology solution that can take into account low cost, high precision, high reliability and easy control. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a spaceborne antenna pointing mechanism and its control method, which solves the problems of high cost and low control accuracy of existing antenna pointing mechanisms.

[0007] Firstly, in order to achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A spaceborne antenna pointing mechanism includes an antenna reflector, a dual-axis antenna pointing mechanism, an antenna support, and a locking and releasing device. The bottom of the dual-axis antenna pointing mechanism is fixed to the antenna support. The top of the dual-axis antenna pointing mechanism is equipped with the antenna reflector. The lower end of the locking and releasing device is connected to the antenna support, and the upper end of the locking and releasing device is connected to the dual-axis antenna pointing mechanism. The dual-axis antenna pointing mechanism includes an elevation bracket, the bottom of which is fixed to the antenna support. An elevation data transmission mechanism is mounted on the elevation bracket. A horizontal bracket is connected to the elevation data transmission mechanism. A horizontal data transmission mechanism is disposed inside the horizontal bracket, and a reflector support frame is connected to the horizontal data transmission mechanism. The antenna reflector is mounted on the reflector support frame. An optical prism is also mounted on the elevation bracket.

[0009] In this design, the horizontal data transmission mechanism is used to adjust the horizontal rotation angle of the reflector support frame, while the elevation data transmission mechanism is used to adjust the elevation rotation angle of the entire system consisting of the horizontal support, the horizontal data transmission mechanism, and the reflector support frame. A locking and releasing device connects the antenna support and the dual-axis pointing mechanism to prevent movement between them during satellite launch. After the satellite enters orbit, the locking and releasing device releases the connection between the two. An optical prism is fixed to the elevation support frame to accurately measure and adjust the angle between the elevation support frame and the antenna support frame, ensuring the dual-axis pointing mechanism reaches its zero position.

[0010] Furthermore, the horizontal data transmission mechanism has the same structure as the pitch data transmission mechanism;

[0011] Both the horizontal and pitch data transmission mechanisms include a housing, the end of which is connected to the outer flange of the stepper motor; the output shaft of the stepper motor is fixedly connected to the harmonic reducer wave generator by screws; a harmonic reducer flexible wheel is sleeved on the harmonic reducer wave generator; the harmonic reducer flexible wheel is deformed under the squeezing action of the harmonic reducer wave generator, and after deformation, the outer part of the harmonic reducer flexible wheel meshes with the inner part of the harmonic reducer rigid wheel; the harmonic reducer rigid wheel is fixed inside the housing;

[0012] The end of the flex wheel of the harmonic reducer away from the harmonic reducer wave generator is fixedly connected to the end of the rotary transformer rotor by screws; the rotary transformer stator is movably connected to the outside of the rotary transformer rotor, and the rotary transformer stator is fixed inside the housing; a rotary transformer position feedback line is led out from the copper wire winding of the rotary transformer stator and passes through the side of the housing; a carrier signal line is led out from the copper wire winding of the rotary transformer rotor and passes through the inside of the rotary transformer rotor;

[0013] The housing of the horizontal data transmission mechanism is mounted on a horizontal support via a flange; the rotary transformer rotor of the horizontal data transmission mechanism is connected to the reflector support frame via a keyway drive.

[0014] The housing of the pitch data transmission mechanism is mounted on the pitch support via a flange; the rotary transformer rotor of the pitch data transmission mechanism passes through the horizontal support and is sleeved onto the inner ring of bearing C; the outer ring of bearing C is fixed on the pitch support.

[0015] In this scheme, both the horizontal and pitch data transmission mechanisms use stepper motors as their power components. This is low-cost, has simple control logic, and because they can achieve a self-locking effect through their own magnetism after power failure, it reduces the overall power consumption of the satellite after the antenna is powered off. Taking the horizontal data transmission mechanism as an example, when adjusting the angle, the stepper motor drives the harmonic reducer wave generator to rotate continuously. The flex wheel of the harmonic reducer acts as the driven wheel, driving the rotor of the rotary transformer to rotate, thereby driving the reflector support frame to adjust the angle. The harmonic reducer has a reduction ratio of 100:1, which can reduce the step angle of the stepper motor from 1.8° to 0.018°, improving the overall transmission accuracy of the horizontal data transmission mechanism. The horizontal data transmission mechanism inputs a sinusoidal excitation signal through a carrier signal line and outputs two modulated signals with a 90-degree phase difference through the position feedback line of the rotary transformer. After subsequent decoding and calculation, the required position information can be accurately obtained. There is a rigid connection between the output shaft of the stepper motor and the harmonic reducer wave generator, as well as between the flex wheel of the harmonic reducer and the rotor of the rotary transformer. The rotary transformer can provide feedback on the precise position of the stepper motor.

[0016] Furthermore, the rotor of the rotary transformer is movably connected to the housing via bearings A and B; a harmonic plug is connected to the end of the housing away from the stepper motor via screws, and the harmonic plug presses and fixes bearing B and the stator of the rotary transformer.

[0017] Furthermore, the material of the rigid wheel of the harmonic reducer is 40CrMnMo, with surface nitriding treatment; the material of the flexible wheel of the harmonic reducer is 30CrMnSiA, with isothermal deformation heat treatment.

[0018] The tooth surfaces of the flexible wheel and rigid wheel of the harmonic reducer are coated with a molybdenum disulfide-resin-based solid lubricating dry film.

[0019] Furthermore, the locking and releasing device includes a bolt housing, a base connected to the bottom of the bolt housing, and the bottom of the base being mounted on the top of the antenna support by screws; a sensor is mounted on the top of the base; an L-shaped fixing bracket is provided on the top of the bolt housing; one end of the fixing bracket is connected to the bolt housing by a slotted bolt; the other end of the fixing bracket is mounted on the reflector support frame; and a recovery cap is mounted on the top of the fixing bracket by bolts.

[0020] An expansion coil is fitted onto the grooving bolt, with the bottom of the expansion coil abutting against the flange at the bottom of the grooving bolt; a lock nut is threaded onto the top of the grooving bolt; a cutting groove is provided on the grooving bolt between the fixed bracket and the bolt housing; the expansion coil expands when energized and heated, stretching the grooving bolt; the grooving bolt breaks at the cutting groove.

[0021] In this design, before the satellite enters orbit, a locking and releasing device is used to lock the dual-axis pointing mechanism and antenna support of the antenna, reducing the overall size of the satellite and ensuring that the overall outer envelope size is smaller than the inner diameter of the rocket cabin, thus preventing damage to the antenna during launch. After the satellite enters orbit, an unlocking signal is sent. The expansion coil is energized and heated, increasing in size and stretching the slotted bolt. The cut groove of the slotted bolt is a weak point, and the bolt breaks at this weak point during stretching. The recovery cap is used to recover the upper part of the broken slotted bolt, preventing impact on other satellite components. The lower part of the broken slotted bolt touches the sensor, and the sensor, under pressure, sends a release signal, completing the closed loop of the unlocking and release process.

[0022] Furthermore, positioning pin A is inserted into the positioning pin holes of the horizontal bracket and the reflector support frame, and positioning pin B is inserted into the positioning pin holes of the horizontal bracket and the pitch bracket.

[0023] In this scheme, positioning pin A positions the reflector support frame to ensure that the reflector support frame is at the zero position of the rotation of the horizontal data transmission mechanism during installation; positioning pin B positions the horizontal bracket and the pitch bracket to ensure that the pitch bracket is perpendicular to the horizontal bracket during installation.

[0024] Secondly, based on the first aspect, the present invention provides a satellite-borne antenna pointing mechanism and a control method for the satellite-borne antenna pointing mechanism, comprising the following steps:

[0025] Step S1: After the satellite enters orbit, the satellite system sends an unlocking signal. After the expansion coil is energized, it expands due to heat and breaks the slotted bolt, completing the unlocking and release. The constraint between the dual-axis pointing mechanism of the antenna and the antenna support is eliminated. The broken part of the slotted bolt touches the sensor and sends a release signal.

[0026] Step S2: The satellite arrives at the working area, and the satellite system sends an antenna power-on signal to prepare for target scanning;

[0027] Step S3: The satellite system reads the absolute position θ of the current stepper motor output shaft fed back by the position feedback line of the rotary transformer. 绝对 ;

[0028] Step S4: The satellite system determines the current absolute position θ 绝对 With the target position θ preset in the satellite system 目标 Determine the absolute value of the deviation |Δθ|:

[0029] |Δθ|=θ 目标 -θ 绝对

[0030] The absolute value of the deviation |Δθ| is then compared with the preset tolerance threshold ε.

[0031] Step S5: Silent calibration based on the comparison results;

[0032] When |Δθ|>ε, the satellite system controls the dual-axis pointing mechanism of the antenna to perform calibration until |Δθ|≤ε.

[0033] When |Δθ|≤ε, meaning that the satellite antenna pointing mechanism satisfies |Δθ|≤ε as soon as it is powered on, the satellite system records the microstep coordinate θ of the stepper motor at the current moment. 记录 The power supply to the stepper motor is disconnected, and the stepper motor maintains its current position by relying on its own magnetism, thus achieving self-locking after power failure.

[0034] Step S6: The satellite system performs periodic monitoring and out-of-synchronization fault tolerance on the onboard antenna pointing mechanism.

[0035] Furthermore, in step S4, the tolerance threshold ε is set to 0.03° based on the accuracy requirements and noise level.

[0036] Furthermore, in step S5, the calibration steps for the dual-axis pointing mechanism of the satellite system control antenna include:

[0037] Path planning: The satellite system converts the absolute value of the deviation |Δθ| into the total number of microsteps that the stepper motor needs to take, and plans an S-shaped velocity curve to smoothly limit acceleration and deceleration;

[0038] Microstep drive: The satellite system sends pulse signals of a corresponding number and frequency to the stepper motor according to the planned S-shaped velocity curve, driving the stepper motor to operate in a 1 / 256 microstep mode;

[0039] Position determination: During the driving process, the satellite system continuously acquires the absolute position θ of the current stepper motor output shaft fed back by the position feedback line of the rotary transformer. 绝对 until |θ 目标 -θ 绝对 When |≤ε, the calibration is considered complete, and pulse output is stopped.

[0040] Further, step S6 includes the following steps:

[0041] Feedback Reading: In open-loop hold mode, the satellite system initiates a timed interrupt with a period of T; within each period T, the satellite system continuously reads the absolute position θ of the current stepper motor output shaft from the position feedback line of the resolver. 绝对 ;

[0042] Loss of synchronization detection: Calculate the absolute position θ 绝对 Compared with the microstep coordinate θ in step S5 记录If the absolute value of the deviation is less than or equal to the tolerance threshold ε, the satellite system continues to maintain an open-loop state; if the absolute value of the deviation is greater than the tolerance threshold ε, it is determined that a loss-of-synchronization event has occurred, and the satellite system repeats step S5 to start a silent calibration operation and drive the antenna back to the correct target position.

[0043] Log recording: The occurrence time and magnitude of the out-of-step event are recorded in non-volatile memory for use in downlink telemetry and ground analysis.

[0044] The beneficial effects of this invention are:

[0045] The satellite-borne antenna pointing mechanism provided by this invention uses a stepper motor to drive the horizontal data transmission mechanism and the pitch data transmission mechanism, resulting in low cost and simple control logic. Furthermore, because it can achieve a self-locking effect through its own magnetism after power failure, it reduces the overall power consumption of the satellite after power loss. Before the satellite enters orbit, the locking and releasing device locks the dual-axis pointing mechanism and antenna support, reducing the overall size of the satellite while preventing damage to the antenna during the launch phase. After the satellite enters orbit, it sends an unlocking signal. The expansion coil, after being energized, heats up and its size increases, stretching the slotted bolt. The slotted bolt breaks at the cut-out slot, releasing the constraint on the dual-axis pointing mechanism and antenna support.

[0046] The control method for the satellite-borne antenna pointing mechanism provided by this invention improves the pointing accuracy of the mechanism from the 1.8° level of the open-loop stepper motor to <±0.1° through "full closed-loop output" measurement and "silent calibration," achieving performance comparable to high-end servo systems. Using a low-cost stepper motor as the main component, and through ingenious sensor configuration and intelligent algorithms, it achieves near-servo system reliability, solving the technical challenges of step loss and absolute position loss. During operation, the satellite-borne antenna pointing mechanism operates in an "open-loop hold" mode, with power consumption far lower than that of a continuously closed-loop servo system, making it particularly suitable for small satellites with high power consumption requirements. Upon power-up, the satellite system can acquire the absolute position θ. 绝对 It eliminates the need for zero-finding and enables fully autonomous out-of-step detection and automatic recovery in orbit, greatly enhancing its intelligence and survivability. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of a spaceborne antenna pointing mechanism according to the present invention;

[0048] Figure 2 This is a side view of a spaceborne antenna pointing mechanism according to the present invention;

[0049] Figure 3 This is a schematic diagram of the antenna dual-axis pointing mechanism in this invention;

[0050] Figure 4 This is a cross-sectional view of the horizontal data transmission mechanism in this invention;

[0051] Figure 5 This is a schematic diagram of the locking and releasing device in this invention;

[0052] Figure 6 This is a cross-sectional view of the locking and releasing device in this invention.

[0053] Figure label:

[0054] 1. Antenna reflector; 2. Antenna dual-axis pointing mechanism; 21. Reflector support frame; 22. Positioning pin A; 23. Horizontal bracket; 24. Horizontal data transmission mechanism; 241. Stepper motor; 242. Harmonic reducer wave generator; 243. Harmonic reducer rigid wheel; 244. Harmonic reducer flexible wheel; 245. Bearing A; 246. Housing; 247. Rotary transformer stator; 248. Bearing B; 249. Carrier signal line; 2410 1. Rotary transformer rotor; 2411. Harmonic plug; 2412. Rotary transformer position feedback line; 25. Pitch support; 26. Pitch data transmission mechanism; 27. Positioning pin B; 28. Bearing C; 29. ​​Optical prism; 3. Antenna support; 4. Locking release device; 41. Recovery cap; 42. Fixing bracket; 43. Locking nut; 44. Grooved bolt; 45. Expansion coil; 46. Bolt housing; 47. Sensor; 48. Base; Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Specific embodiments of the present invention are described below to facilitate understanding by those skilled in the art. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various modifications are obvious as long as they fall within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0056] Example 1

[0057] like Figure 1 and Figure 2 As shown, this embodiment provides a spaceborne antenna pointing mechanism that combines the advantages of low cost, high precision, and high reliability, and is easy to control; specifically, it includes:

[0058] Antenna reflector 1, antenna dual-axis pointing mechanism 2, antenna support 3, and locking and releasing device 4;

[0059] The bottom of the dual-axis pointing mechanism 2 is fixed on the antenna support 3; the top of the dual-axis pointing mechanism 2 is equipped with an antenna reflector 1; the lower end of the locking and releasing device 4 is connected to the antenna support 3, and the upper end of the locking and releasing device 4 is connected to the dual-axis pointing mechanism 2. After the satellite enters orbit, the locking and releasing device 4 releases the connection between the two.

[0060] like Figure 3 As shown, the dual-axis pointing mechanism 2 of the antenna includes a reflector support frame 21, a positioning pin A22, a horizontal bracket 23, a horizontal data transmission mechanism 24, an elevation bracket 25, an elevation data transmission mechanism 26, a positioning pin B27, a bearing C28, and an optical prism 29. The bottom of the elevation bracket 25 is fixed to the antenna support 3; the elevation data transmission mechanism 26 is mounted on the elevation bracket 25; the horizontal bracket 23 is connected to the elevation data transmission mechanism 26; the positioning pin B27 is inserted into the positioning pin holes of the horizontal bracket 23 and the elevation bracket 25, and the positioning pin B27 positions the horizontal bracket 23 and the elevation bracket 25 to ensure that the elevation bracket 25 is perpendicular to the horizontal bracket 23 during installation. A horizontal data transmission mechanism 24 is installed inside the horizontal support 23, and a reflector support frame 21 is connected to the horizontal data transmission mechanism 24. Positioning pins A22 are inserted into the positioning pin holes of the horizontal support 23 and the reflector support frame 21, positioning the reflector support frame 21 to ensure that it is in the zero-rotation position of the horizontal data transmission mechanism 24 during installation. The antenna reflector 1 is mounted on the reflector support frame 21. The horizontal data transmission mechanism 24 is used to adjust the horizontal rotation angle of the reflector support frame 21, and the elevation data transmission mechanism 26 is used to adjust the elevation rotation angle of the entire structure consisting of the horizontal support 23, the horizontal data transmission mechanism 24, and the reflector support frame 21. An optical prism 29 is also installed on the elevation support 25. The optical prism 29 is fixed on the elevation support 25 and is used to accurately measure and adjust the angle between the elevation support 25 and the antenna support 3, so that the antenna dual-axis pointing mechanism 2 reaches the zero position.

[0061] The horizontal data transmission mechanism 24 and the pitch data transmission mechanism 26 have the same structure.

[0062] like Figure 4As shown, both the horizontal data transmission mechanism 24 and the pitch data transmission mechanism 26 include a stepper motor 241, a harmonic reducer wave generator 242, a harmonic reducer rigid wheel 243, a harmonic reducer flexible wheel 244, a bearing A 245, a housing 246, a rotary transformer stator 247, a bearing B 248, a carrier signal line 249, a rotary transformer rotor 2410, a harmonic plug 2411, and a rotary transformer position feedback line 2412. The end of the housing 246 is connected to the outer flange of the stepper motor 241; the output shaft of the stepper motor 241 is axially fixed to the harmonic reducer wave generator 242 by screws, and radial rotation is prevented by set screws. A harmonic reducer flexure 244 is fitted onto the harmonic reducer wave generator 242. The flexure 244 deforms under the compression of the harmonic reducer wave generator 242, and its external part meshes with the internal part of the harmonic reducer rigid wheel 243. The rigid wheel 243 is fixed inside the housing 246. The end of the flexure 244 away from the harmonic reducer wave generator 242 is fixedly connected to the end of the rotary transformer rotor 2410 by screws. A rotary transformer stator 247 is movably connected to the rotary transformer rotor 2410 and is fixed inside the housing 246. The rotary transformer rotor 2410 and the housing 246 are movably connected by bearings A245 and B248. A harmonic plug 2411 is connected to the end of the housing 246 away from the stepper motor 241 by screws, and the harmonic plug 2411 presses and fixes the bearing B248 and the rotary transformer stator 247. A position feedback line 2412 is led out from the copper wire winding of the stator 247 of the rotary transformer, and the position feedback line 2412 passes through the side of the housing 246; a carrier signal line 249 is led out from the copper wire winding of the rotor 2410 of the rotary transformer, and the carrier signal line 249 passes through the inside of the rotor 2410 of the rotary transformer.

[0063] In the horizontal data transmission mechanism 24, the housing 246 of the horizontal data transmission mechanism 24 is mounted on the horizontal support 23 via a flange; the rotary transformer rotor 2410 of the horizontal data transmission mechanism 24 is connected to the reflector support frame 21 via a key drive. When adjusting the angle, the stepper motor 241 of the horizontal data transmission mechanism 24 drives the harmonic reducer wave generator 242 to rotate continuously. The harmonic reducer flexure 244, as the driven wheel, drives the rotary transformer rotor 2410 to rotate, thereby driving the reflector support frame 21 to adjust the angle. The harmonic reducer has a reduction ratio of 100:1, which can reduce the step angle of the stepper motor 241 from 1.8° to 0.018°, thereby improving the overall transmission accuracy of the horizontal data transmission mechanism 24. The horizontal data transmission mechanism 24 inputs a sinusoidal excitation signal through the carrier signal line 249 and outputs two modulated signals with a 90-degree phase difference through the rotary transformer position feedback line 2412. After subsequent decoding and calculation, the required position information can be accurately obtained. There is a rigid connection between the output shaft of the stepper motor 241 and the harmonic reducer wave generator 242, as well as between the harmonic reducer flexure 244 and the rotary transformer rotor 2410. The rotary transformer can provide feedback on the precise position of the stepper motor 241.

[0064] In the pitch data transmission mechanism 26, the housing 246 of the pitch data transmission mechanism 26 is mounted on the pitch support 25 via a flange; the rotary transformer rotor 2410 of the pitch data transmission mechanism 26 passes through the horizontal support 23 and is sleeved onto the inner ring of the bearing C28; the outer ring of the bearing C28 is fixed on the pitch support 25. When adjusting the angle, the rotary transformer rotor 2410 of the pitch data transmission mechanism 26 drives the horizontal support 23 to rotate.

[0065] In this embodiment, the power components of the horizontal data transmission mechanism 24 and the pitch data transmission mechanism 26 are both stepper motors 241, which are low in cost, have simple control logic, and can achieve a self-locking effect through their own magnetism after power failure, thereby reducing the overall power consumption of the satellite after the antenna is powered off.

[0066] The rigid wheel 243 of the harmonic reducer is made of 40CrMnMo with a nitrided surface; the flexible wheel 244 is made of 30CrMnSiA with isothermal deformation heat treatment, resulting in a material strength greater than 550MPa. The tooth surfaces of both the flexible wheel 244 and the rigid wheel 243 are coated with a molybdenum disulfide-resin-based solid lubricant dry film to adapt to the space environment and extend their service life.

[0067] like Figure 5 and Figure 6As shown, the locking and releasing device 4 includes a retrieval cap 41, a fixing bracket 42, a locking nut 43, a slotted bolt 44, an expansion coil 45, a bolt housing 46, a sensor 47, and a base 48. The bottom of the bolt housing 46 is connected to the base 48, and the bottom of the base 48 is mounted on the top of the antenna support 3 by screws; the sensor 47 is mounted on the top of the base 48; the top of the bolt housing 46 is provided with an L-shaped fixing bracket 42; one end of the fixing bracket 42 is connected to the bolt housing 46 by the slotted bolt 44; the other end of the fixing bracket 42 is mounted on the reflector support frame 21; the retrieval cap 41 is mounted on the top of the fixing bracket 42 by bolts. An expansion coil 45 is fitted onto the grooving bolt 44, and the bottom of the expansion coil 45 abuts against the flange at the bottom of the grooving bolt 44; a locking nut 43 is threaded onto the top of the grooving bolt 44; a cutting groove is provided on the grooving bolt 44 at the position between the fixed bracket 42 and the bolt housing 46; after the expansion coil 45 is energized and heated, it expands and stretches the grooving bolt 44; the grooving bolt 44 breaks at the cutting groove position.

[0068] Before the satellite enters orbit, the locking and releasing device 4 locks the dual-axis pointing mechanism 2 and the antenna support 3, reducing the overall size of the satellite and ensuring that the overall outer envelope size is smaller than the inner diameter of the rocket cabin, preventing damage to the antenna during launch. After the satellite enters orbit, it sends an unlocking signal. The expansion coil 45 is energized and heated, increasing in size and stretching the slotted bolt 44. The cut groove of the slotted bolt 44 is a weak point, and the bolt breaks at this weak point during the stretching process. The recovery cap 41 is used to recover the upper broken part of the slotted bolt 44, preventing impact on other satellite components. The lower broken part of the slotted bolt 44 touches the sensor 47, and the sensor 47 sends a release signal after being stressed, completing the closed loop of the unlocking and releasing process.

[0069] Example 2

[0070] This embodiment, based on the satellite antenna pointing mechanism provided in Embodiment 1, provides a control method for the satellite antenna pointing mechanism, including the following steps:

[0071] Step S1: After the satellite enters orbit, the satellite system sends an unlocking signal. The expansion coil 45, energized and heated, rapidly expands. At this time, the upper end of the slotted bolt 44 is locked by the locking nut 43, while the lower end is pulled downwards by the expansion coil 45. The slotted bolt 44 is pulled off at the cut-out slot, completing the unlocking and release process. The constraint between the antenna dual-axis pointing mechanism 2 and the antenna support 3 is eliminated. After breaking, the upper part of the locking nut 43 and the broken slotted bolt 44 enters the recovery cap 41 to prevent impact on other satellite components. The lower part of the broken slotted bolt 44 touches the sensor 47, sending a release signal.

[0072] Step S2: The satellite arrives at the working area, and the satellite system sends an antenna power-on signal to prepare for target scanning.

[0073] Step S3: The satellite system reads the absolute position θ of the current output shaft of the stepper motor 241 from the position feedback line 2412 of the rotary transformer. 绝对 This allows the satellite system to know the true direction of the antenna the moment it is powered on, without needing to perform any form of zeroing or reset operation.

[0074] Step S4: The satellite system determines the current absolute position θ 绝对 With the target position θ preset in the satellite system 目标 Determine the absolute value of the deviation |Δθ|:

[0075] |Δθ|=θ 目标 -θ 绝对

[0076] The absolute value of the deviation, |Δθ|, is compared with the preset tolerance threshold ε; the tolerance threshold ε is set to 0.03° based on the accuracy requirements and noise level.

[0077] Step S5: Silent calibration based on the comparison results;

[0078] When |Δθ|>ε, the satellite system control antenna dual-axis pointing mechanism 2 performs calibration until |Δθ|≤ε; the calibration steps are as follows:

[0079] Path planning: The satellite system converts the absolute value of the deviation |Δθ| into the total number of microsteps that the stepper motor 241 needs to take. To avoid impact, an S-shaped velocity curve is planned, and acceleration and deceleration are smoothly limited.

[0080] Microstep drive: According to the planned S-shaped velocity curve, the satellite system sends pulse signals of a corresponding number and frequency to the stepper motor 241, driving the stepper motor 241 to operate in a 1 / 256 microstep mode.

[0081] Position determination: During the driving process, the satellite system continuously acquires the absolute position θ of the current output shaft of the stepper motor 241, fed back by the position feedback line 2412 of the rotary transformer. 绝对 until |θ 目标 -θ 绝对 When |≤ε, the calibration is considered complete, and pulse output is stopped.

[0082] When |Δθ|≤ε, that is, when the satellite antenna pointing mechanism satisfies |Δθ|≤ε as soon as it is powered on, the satellite system records the microstep coordinate θ of the stepper motor 241 at the current moment. 记录 The power supply to the stepper motor 241 is disconnected, and the stepper motor 241 maintains its current position by relying on its own magnetism, thus achieving self-locking after power failure.

[0083] Step S6: The satellite system performs periodic monitoring and out-of-synchronization fault tolerance on the onboard antenna pointing mechanism. The specific steps are as follows:

[0084] Feedback Reading: Under open-loop hold, the satellite system initiates a timed interrupt with a period of T; within each period T, the satellite system continuously reads the absolute position θ of the current stepper motor 241 output shaft from the rotary transformer position feedback line 2412. 绝对 ;

[0085] Loss of synchronization detection: Calculate the absolute position θ 绝对 Compared with the microstep coordinate θ in step S5 记录 If the absolute value of the deviation is less than or equal to the tolerance threshold ε, the satellite system continues to maintain an open-loop state; if the absolute value of the deviation is greater than the tolerance threshold ε, it is determined that a loss-of-synchronization event has occurred, and the satellite system repeats step S5 to start a silent calibration operation and drive the antenna back to the correct target position.

[0086] Log recording: The occurrence time and magnitude of the out-of-step event are recorded in non-volatile memory for use in downlink telemetry and ground analysis.

[0087] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention and should be understood as not limiting the scope of protection of the invention to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed herein without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the invention.

Claims

1. A pointing mechanism for a spaceborne antenna, characterized in that: It includes an antenna reflector (1), an antenna dual-axis pointing mechanism (2), an antenna support (3), and a locking and releasing device (4); the bottom of the antenna dual-axis pointing mechanism (2) is fixed on the antenna support (3); the antenna reflector (1) is installed on the top of the antenna dual-axis pointing mechanism (2); the lower end of the locking and releasing device (4) is connected to the antenna support (3), and the upper end of the locking and releasing device (4) is connected to the antenna dual-axis pointing mechanism (2); The dual-axis pointing mechanism (2) of the antenna includes an elevation bracket (25), the bottom of which is fixed on the antenna support (3); an elevation data transmission mechanism (26) is installed on the elevation bracket (25); a horizontal bracket (23) is connected to the elevation data transmission mechanism (26); a horizontal data transmission mechanism (24) is provided inside the horizontal bracket (23), and a reflector support frame (21) is connected to the horizontal data transmission mechanism (24); the antenna reflector (1) is installed on the reflector support frame (21); an optical prism (29) is also installed on the elevation bracket (25). The horizontal data transmission mechanism (24) has the same structure as the pitch data transmission mechanism (26); Both the horizontal data transmission mechanism (24) and the pitch data transmission mechanism (26) include a housing (246), the end of which is connected to the outer flange of the stepper motor (241); the output shaft of the stepper motor (241) is fixedly connected to the harmonic reducer wave generator (242) by screws; a harmonic reducer flexible wheel (244) is sleeved on the harmonic reducer wave generator (242); the harmonic reducer flexible wheel (244) is deformed under the squeezing action of the harmonic reducer wave generator (242), and after deformation, the outer part of the harmonic reducer flexible wheel (244) meshes with the inner part of the harmonic reducer rigid wheel (243); the harmonic reducer rigid wheel (243) is fixed inside the housing (246). The end of the harmonic reducer flexure (244) away from the harmonic reducer wave generator (242) is fixedly connected to the end of the rotary transformer rotor (2410) by screws; a rotary transformer stator (247) is movably connected to the rotary transformer rotor (2410), and the rotary transformer stator (247) is fixed inside the housing (246); a rotary transformer position feedback line (2412) is led out from the copper wire winding of the rotary transformer stator (247), and the rotary transformer position feedback line (2412) passes through the side of the housing (246); a carrier signal line (249) is led out from the copper wire winding of the rotary transformer rotor (2410), and the carrier signal line (249) passes through the inside of the rotary transformer rotor (2410); The housing (246) of the horizontal data transmission mechanism (24) is mounted on the horizontal support (23) via a flange; the rotary transformer rotor (2410) of the horizontal data transmission mechanism (24) is connected to the reflector support frame (21) via a key drive. The housing (246) of the pitch data transmission mechanism (26) is mounted on the pitch support (25) via a flange; the rotary transformer rotor (2410) of the pitch data transmission mechanism (26) passes through the horizontal support (23) and is sleeved onto the inner ring of the bearing C (28); the outer ring of the bearing C (28) is fixed on the pitch support (25).

2. The satellite antenna pointing mechanism according to claim 1, characterized in that: The rotor (2410) of the rotary transformer is movably connected to the housing (246) via bearing A (245) and bearing B (248); a harmonic plug (2411) is connected to the end of the housing (246) away from the stepper motor (241) by screws, and the harmonic plug (2411) presses and fixes the bearing B (248) and the stator (247) of the rotary transformer.

3. The satellite antenna pointing mechanism according to claim 1, characterized in that: The material of the rigid wheel (243) of the harmonic reducer is 40CrMnMo, and the surface is nitrided; the material of the flexible wheel (244) of the harmonic reducer is 30CrMnSiA, and it is subjected to isothermal deformation heat treatment. The tooth surfaces of the flex wheel (244) and the rigid wheel (243) of the harmonic reducer are coated with a molybdenum disulfide-resin-based solid lubricating dry film.

4. The satellite antenna pointing mechanism according to claim 1, characterized in that: The locking and releasing device (4) includes a bolt housing (46), the bottom of which is connected to a base (48), the bottom of which is mounted on the top of the antenna support (3) by screws; a sensor (47) is mounted on the top of the base (48); an L-shaped fixing bracket (42) is provided on the top of the bolt housing (46); one end of the fixing bracket (42) is connected to the bolt housing (46) by a slotted bolt (44); the other end of the fixing bracket (42) is mounted on the reflector support frame (21); a recovery cap (41) is mounted on the top of the fixing bracket (42) by bolts. An expansion coil (45) is sleeved on the grooving bolt (44), and the bottom of the expansion coil (45) abuts against the flange at the bottom of the grooving bolt (44); a locking nut (43) is threaded to the top of the grooving bolt (44); a cutting groove is provided on the grooving bolt (44) at the position between the fixed bracket (42) and the bolt housing (46); the expansion coil (45) expands after being energized and heated, and stretches the grooving bolt (44); the grooving bolt (44) breaks at the cutting groove position.

5. The satellite antenna pointing mechanism according to claim 1, characterized in that: Positioning pin A (22) is inserted into the positioning pin hole of the horizontal bracket (23) and the reflective surface support frame (21), and positioning pin B (27) is inserted into the positioning pin hole of the horizontal bracket (23) and the pitch bracket (25).

6. A control method for a spaceborne antenna pointing mechanism according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: After the satellite enters orbit, the satellite system sends an unlocking signal. After the expansion coil (45) is energized, it expands due to heat and breaks the slotted bolt (44), thus completing the unlocking and release. The constraint between the antenna dual-axis pointing mechanism (2) and the antenna support (3) is eliminated. The broken part of the slotted bolt (44) touches the sensor (47) and sends a release signal. Step S2: The satellite arrives at the working area, and the satellite system sends an antenna power-on signal to prepare for target scanning; Step S3: The satellite system reads the absolute position θ of the current stepper motor (241) output shaft from the position feedback line (2412) of the rotary transformer. 绝对 ; Step S4: The satellite system determines the current absolute position θ 绝对 With the target position θ preset in the satellite system 目标 Determine the absolute value of the deviation |Δθ|: |Δθ|=θ 目标 -θ 绝对 The absolute value of the deviation |Δθ| is then compared with the preset tolerance threshold ε. Step S5: Silent calibration based on the comparison results; When |Δθ|>ε, the satellite system controls the dual-axis pointing mechanism (2) of the antenna to run and calibrate until |Δθ|≤ε; When |Δθ|≤ε, that is, when the satellite antenna pointing mechanism satisfies |Δθ|≤ε as soon as it is powered on, the satellite system records the microstep coordinate θ of the stepper motor (241) at the current moment. 记录 And disconnect the power supply to the stepper motor (241). The stepper motor (241) maintains its current position by relying on its own magnetism, thus achieving power-off self-locking. Step S6: The satellite system performs periodic monitoring and out-of-synchronization fault tolerance on the onboard antenna pointing mechanism.

7. The control method for the pointing mechanism of the spaceborne antenna according to claim 6, characterized in that: In step S4, the tolerance threshold ε is set to 0.03° based on the accuracy requirements and noise level.

8. The control method for the pointing mechanism of the spaceborne antenna according to claim 6, characterized in that: In step S5, the calibration steps for the dual-axis pointing mechanism (2) of the satellite system control antenna include: Path planning: The satellite system converts the absolute value of the deviation |Δθ| into the total number of microsteps that the stepper motor (241) needs to take, and plans an S-shaped velocity curve to smoothly limit the acceleration and deceleration; Microstep drive: The satellite system sends pulse signals of a corresponding number and frequency to the stepper motor (241) according to the planned S-shaped velocity curve, driving the stepper motor (241) to run in a 1 / 256 microstep mode; Position determination: During the driving process, the satellite system continuously collects the absolute position θ of the current stepper motor (241) output shaft from the position feedback line (2412) of the rotary transformer. 绝对 until |θ 目标 -θ 绝对 When |≤ε, the calibration is considered complete, and pulse output is stopped.

9. The control method for the pointing mechanism of the spaceborne antenna according to claim 8, characterized in that: Step S6 includes the following steps: Feedback Reading: Under open-loop hold, the satellite system initiates a timed interrupt with a period of T; within each period T, the satellite system continuously reads the absolute position θ of the current stepper motor (241) output shaft from the rotary transformer position feedback line (2412). 绝对 ; Loss of synchronization detection: Calculate the absolute position θ 绝对 Compared with the microstep coordinate θ in step S5 记录 If the absolute value of the deviation is less than or equal to the tolerance threshold ε, the satellite system continues to maintain an open-loop state; if the absolute value of the deviation is greater than the tolerance threshold ε, it is determined that a loss-of-synchronization event has occurred, and the satellite system repeats step S5 to start a silent calibration operation and drive the antenna back to the correct target position. Log recording: The occurrence time and magnitude of the out-of-step event are recorded in non-volatile memory for use in downlink telemetry and ground analysis.

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