High-precision and high-reliability driving shaft system device for space and calibration method

Abstract

The application discloses a high-precision and high-reliability driving shaft system device for space and a calibration method. The device comprises, from right to left, a supporting bearing assembly, a sensor assembly, a speed reducer and a driving motor. The speed reducer is installed between the supporting bearing assembly and the driving motor, so that the low-speed and large-torque output characteristics can be realized. The sensor assembly is highly integrated in a structural member and is installed at the output end of the speed reducer. The application can realize self-adaptive adjustment of the internal pre-tightening force of the shaft system and can be used in both ground and space environments. Meanwhile, the application uses a combination of linear Hall and switch Hall, is highly integrated in the driving shaft system structural member, does not occupy additional product space and reduces the envelope size of the driving shaft system. In addition, the application is convenient to implement, can further improve the position detection precision of the sensor assembly through a calibration device, has both ground and on-orbit calibration functions and can be accurately controlled.

Description

Technical Field

[0001] This invention belongs to the field of satellite actuators, specifically relating to a high-precision and high-reliability drive shaft system device and calibration method for space applications. Background Technology

[0002] A drive shaft system is an actuator primarily used to rotate space payloads to achieve wide field-of-view coverage. With the increasing number of satellites in orbit and the continuous advancement of space defense and offensive technologies in my country, the demand for high-precision, stable control, long-life, and highly reliable operation of spacecraft is becoming increasingly strong. Low-speed shaft systems for space use, as core components, not only require simple structures and high rotational accuracy, but also the ability to withstand axial and radial loads simultaneously, and to output torque. The high precision of low-speed space shaft systems depends primarily on factors such as rotational accuracy, position detection accuracy, external calibration accuracy, and algorithm compensation accuracy.

[0003] In space applications, low-speed shaft support bearing assemblies typically employ a pair of angular contact ball bearings mounted back-to-back to provide a high-rigidity bearing configuration. Under normal operating conditions, bearings require a certain axial load to improve rotational accuracy, reduce rolling element slippage at high speeds, increase bearing rigidity, reduce axial and radial runout of the support, lower noise, and extend bearing life. Higher bearing preload leads to greater friction and requires more driving force from the motor; insufficient motor torque may cause shaft seizure. Conversely, lower preload reduces friction and motor driving force, but decreases axial stiffness and increases runout. Therefore, selecting an appropriate preload is crucial.

[0004] The current common practice for applying preload is to adjust the height difference between the inner and outer spacers of the bearing to achieve preload positioning. However, after entering space orbit, the shaft system is in a weightless state, and the shaft system preload changes compared to the ground. After undergoing force and heat environment tests on the ground, the bearing preload also changes. Furthermore, after long-term operation in orbit, especially in the later stages of the bearing's lifespan, friction and wear will inevitably occur, causing changes in bearing protrusion and other parameters, which will also alter the preload. However, due to the special nature of the operating environment, the shaft system preload cannot be adjusted in space. Therefore, a drive shaft system capable of adaptively adjusting the preload of a space shaft system is needed.

[0005] Furthermore, to ensure the position control accuracy of the shaft system, traditional position sensors such as resolvers, inductive synchronizers, or optical encoders are generally required. These sensors are typically large and relatively heavy, and their accuracy is highly dependent on their size. Conversely, smaller and lighter sensors cannot achieve very high accuracy. Therefore, a small, highly integrated position sensor and its high-precision calibration method are needed to achieve a high-precision and highly reliable shaft system drive. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a high-precision and high-reliability drive shaft system device and calibration method for space applications.

[0007] The technical solution of the present invention is as follows:

[0008] A high-precision and high-reliability drive shaft system device and calibration method for space applications, wherein the high-precision and high-reliability drive shaft system device for space applications includes, from right to left, a support bearing assembly, a sensor assembly, a reducer, and a drive motor;

[0009] A reducer is installed between the support bearing assembly and the drive motor to achieve low-speed, high-torque output characteristics.

[0010] The sensor assembly is highly integrated within the structural components and is installed at the output end of the reducer.

[0011] The support bearing assembly includes a labyrinth seal gland, a spacer, a bearing housing, a bearing, a spindle, a disc spring, and a lock nut.

[0012] The bearing includes a lower bearing and an upper bearing, which are installed back-to-back to increase the bearing span and improve the load-bearing capacity of the shaft assembly; the inner ring of the bearing is a rotating part that is precisely fitted with the spindle, and the outer ring of the bearing is a stationary part that is precisely fitted with the bearing housing.

[0013] The end of the mandrel is axially fixed to the shaft system by a lock nut to prevent the bearing from axially loosening and falling off the load;

[0014] The spacer ring includes an outer spacer ring and an inner spacer ring, and is installed between the upper bearing and the lower bearing; the bearing is axially preloaded by adjusting the height difference of the spacer rings;

[0015] The disc spring is installed between the root end face of the spindle and the lower bearing, which can effectively prevent the active section from being overloaded by impact.

[0016] The labyrinth-type pressure cap is installed on the outer end face of the bearing housing to axially position the outer ring of the bearing.

[0017] The outer spacer is made of intelligent piezoelectric material, and stress plates are attached to four positions on the inner surface as preload measuring elements. The average value of the measurement results of the multiple stress plates is sent to the information processing unit for analysis and processing, and the magnitude of the axial force of the shaft system is monitored and fed back in real time. The axial force of the shaft system is the preload.

[0018] The pre-tightening force should be calibrated before measurement to check whether the error between the measured value of the stress gauge and the actually applied pre-tightening force is within a reasonable range. The specific method is as follows: First, according to the sum of the protrusion amounts of the lower bearing and the upper bearing under the specified preload, grind the inner spacer ring to make the height difference between the outer spacer ring and the inner spacer ring match it, and then measure the frictional force when the outer spacer ring and the bearing slide relative to each other; then, based on the frictional force and the friction coefficient of the bearing end face of the outer spacer ring, indirectly obtain the difference between the actually applied pre-tightening force of the bearing and the pre-tightening force measured by the stress gauge. If the difference is within the allowable range, it will meet the requirements.

[0019] The sensor assembly includes a linear Hall element, a switch Hall element, a magnetic ring and a tuning device, which is highly integrated, lightweight, high-precision and reliable.

[0020] The magnetic field distribution of the magnetic ring in space is complex, and the magnetic field vector is a spatial vector. However, in the present invention, only the spatial magnetic field in the radial direction is the effective detection magnetic field.

[0021] The tuning device tunes the magnetic field distribution of the magnetic ring in space, improves the intensity and sinusoidality of the radial magnetic field, effectively reduces the ineffective tangential magnetic field component, and improves the detection accuracy of the position sensor.

[0022] The linear Hall elements are arranged in a four-way orthogonal layout, evenly distributed at intervals of 90 degrees. By differentiating the linear Hall signals, the anti-interference ability of the signals and the compensation for installation errors can be ensured.

[0023] The switch Hall elements are multiple and are installed at the remaining angles in space. They can calibrate the position error detected by the linear Hall elements on orbit and perform on-orbit compensation through the information processing unit.

[0024] The information processing unit changes according to the change of the pre-tightening force. Once the pre-tightening force exceeds the designed value range, it will adjust the supply voltage of the piezoelectric material, thereby changing the height of the outer spacer ring, realizing the change of the height difference of the spacer ring, and realizing the adjustment of the magnitude of the pre-tightening force.

[0025] The calibration device supporting the high-precision and high-reliability drive shaft system device for space use is a ground calibration device; the ground calibration device sequentially includes a high-precision calibration sensor, a connecting bracket, a support bracket and the high-precision and high-reliability drive shaft system device for space use from left to right; the accuracy of the high-precision calibration sensor is better than 1″.

[0026] The high-precision and high-reliability drive shaft system device for space use and the high-precision calibration sensor are rigidly connected, and can calibrate the 360° position accuracy of the high-precision and high-reliability drive shaft system device for space use in one week, and send the position error to the information processing unit for error compensation.

[0027] The calibration device supporting the high-precision and high-reliability drive shaft system for space is an on-orbit calibration device, which includes a high-precision and high-reliability drive shaft system for space and a star sensor; the star sensor is an essential angle measurement device for satellites and cooperates with the switch Hall to complete on-orbit calibration.

[0028] The calibration method for the high-precision and high-reliability drive shaft system for space is as follows. The specific steps of ground calibration are as follows:

[0029] S1. Install the high-precision and high-reliability drive shaft system for space on one side of the support bracket, and install the high-precision calibration sensor on the other side of the support bracket;

[0030] S2. Use the information processing unit to read the pre-tightening force value of the support bearing assembly in the current state. If there is a deviation from the design value, adjust the height of the outer spacer to make the pre-tightening force meet the design value requirements;

[0031] S3. Use the information processing unit to rotate the high-precision and high-reliability drive shaft system according to the set rotation step and stabilize it at the current position. Compare the angle value feedback by the high-precision and high-reliability drive shaft system itself with the feedback value of the ground high-precision calibration sensor, correct the difference, perform curve fitting on all correction points in one rotation, and load it into the information processing unit as an accuracy improvement compensation curve.

[0032] The calibration method for the high-precision and high-reliability drive shaft system for space is as follows. The specific steps of on-orbit calibration are as follows:

[0033] S1. The high-precision and high-reliability drive shaft system for space rotates according to the specified step. After stabilization, compare and correct the feedback value of the sensor assembly with the detection value of the star sensor;

[0034] S2. Perform curve fitting on all correction points within one circle and load it into the information processing unit to perform error compensation on the entire circle position to improve accuracy. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] [[ID=二十九]] Figure 1 Schematic diagram of the support bearing assembly in the embodiment of the present invention;

[0037] Figure 2 External shape diagram of the outer spacer in the embodiment of the present invention;

[0038] Figure 3This is a schematic diagram of the application process in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the space drive shaft system in an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram comparing the radial and tangential air gap magnetic field curves before and after magnetic field tuning in an embodiment of the present invention.

[0041] Figure 6 This is a ground calibration device for a high-precision and high-reliability drive shaft system for space applications, as described in this embodiment of the invention.

[0042] In the diagram: 1 is the labyrinth seal gland; 2 is the outer spacer ring; 3 is the bearing housing; 4 is the lower bearing; 5 is the spindle; 6 is the disc spring; 7 is the inner spacer ring; 8 is the upper bearing; 9 is the lock nut; 10 is the support bearing assembly; 11 is the sensor assembly; 12 is the reducer; 13 is the drive motor; 14 is the high-precision calibration sensor; 15 is the connecting bracket; 16 is the support bracket; 17 is the stress plate.

[0043] Specific implementation methods

[0044] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0045] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0046] The specific technology is as follows:

[0047] like Figure 4 As shown, a high-precision and high-reliability drive shaft system device and calibration method for space use are disclosed. The high-precision and high-reliability drive shaft system device for space use includes, from right to left, a support bearing assembly 10, a sensor assembly 11, a reducer 12, and a drive motor 13.

[0048] A reducer 12 is installed between the support bearing assembly 10 and the drive motor 13, which can achieve low-speed, high-torque output characteristics.

[0049] The sensor assembly 11 is highly integrated within the structural component and is installed at the output end of the reducer 12.

[0050] like Figure 1 As shown, the support bearing assembly 10 includes a labyrinth seal cap 1, a spacer ring, a bearing seat 3, a bearing, a spindle 5, a disc spring 6, and a lock nut 9.

[0051] The bearing includes a lower bearing 4 and an upper bearing 8, which are installed back-to-back to increase the bearing span and improve the load-bearing capacity of the shaft assembly. The inner ring of the bearing is a rotating part that is precisely fitted with the spindle 5, and the outer ring of the bearing is a stationary part that is precisely fitted with the bearing housing 3.

[0052] The end of the spindle 5 is axially fixed to the shaft system by a lock nut 9 to prevent the bearing from axially loosening and falling off the load;

[0053] The spacer ring includes an outer spacer ring 2 and an inner spacer ring 7, which are installed between the upper bearing 8 and the lower bearing 4; the bearing is axially preloaded by adjusting the height difference of the spacer rings.

[0054] The disc spring 6 is installed between the root end face of the spindle 5 and the lower bearing 4, which can effectively prevent the active section from being overloaded by impact.

[0055] The labyrinth-type pressure cap 1 is installed on the outer end face of the bearing housing 3 to axially position the outer ring of the bearing.

[0056] like Figure 2 As shown, the outer spacer 2 is made of smart piezoelectric material, and stress plates 17 are attached to four positions on the inner surface as preload measuring elements.

[0057] like Figure 3 As shown, the average value of the measurement results of the multiple stress plates 17 is sent to the information processing unit for analysis and processing, and the magnitude of the axial force of the shaft system is monitored and fed back in real time. The axial force of the shaft system is the preload force.

[0058] The preload should be calibrated before measurement to check whether the error between the measured value of the stress plate 17 and the actual applied preload is within a reasonable range. The specific method is as follows: First, based on the sum of the protrusions of the lower bearing 4 and the upper bearing 8 under the specified preload, grind the inner spacer 7 to match the height difference between the outer spacer 2 and the inner spacer 7. Then, measure the frictional force when the outer spacer 2 slides relative to the bearing. Then, based on the frictional force and the friction coefficient of the bearing end face of the outer spacer 2, indirectly determine the difference between the actual applied preload and the preload measured by the stress plate 17. A difference within the allowable range will meet the requirements.

[0059] The sensor assembly 11 includes a linear Hall effect sensor, a switched Hall effect sensor, a magnetic ring, and a setting device, and is highly integrated, lightweight, highly accurate, and reliable.

[0060] like Figure 5As shown in (a) therein, the magnetic field distribution of the magnetic ring in space is complex, and the magnetic field vector is a spatial vector. However, in the present invention, only the spatial magnetic field in the radial direction is the effective detection magnetic field;

[0061] As Figure 5 As shown in (b) therein, the tuning device tunes the magnetic field distribution of the magnetic ring in space, improves the intensity and sinusoidality of the radial magnetic field, effectively reduces the ineffective tangential magnetic field component, and improves the detection accuracy of the position sensor.

[0062] The linear Hall elements are arranged orthogonally in four channels and evenly distributed at an interval of 90 degrees. By differentiating the linear Hall signals, the anti-interference ability of the signals can be ensured and the installation error can be compensated.

[0063] The switch Hall elements are multiple and are installed at the remaining angles in space. They can calibrate the position error detected by the linear Hall elements on orbit and perform on-orbit compensation through the information processing unit;

[0064] The information processing unit changes according to the change of the pre-tightening force. Once the pre-tightening force exceeds the designed value range, the supply voltage of the piezoelectric material will be adjusted, thereby changing the height of the outer spacer 2, realizing the change of the height difference of the spacer, and realizing the adjustment of the magnitude of the pre-tightening force.

[0065] As Figure 6 As shown, the calibration device supporting the high-precision and high-reliability drive shafting device for space is a ground calibration device; the ground calibration device sequentially includes a high-precision calibration sensor 14, a connecting bracket 14, a support bracket 16, and the high-precision and high-reliability drive shafting device for space from left to right; the accuracy of the high-precision calibration sensor is better than 1″;

[0066] The high-precision and high-reliability drive shafting device for space and the high-precision calibration sensor 14 are rigidly connected, and the 360° position accuracy of the high-precision and high-reliability drive shafting device for space can be calibrated, and the position error is sent to the information processing unit for error compensation.

[0067] The calibration device supporting the high-precision and high-reliability drive shafting device for space is an on-orbit calibration device, which includes a high-precision and high-reliability drive shafting device for space and a star sensor; the star sensor is an essential angle measuring device for satellites and cooperates with the switch Hall to complete on-orbit calibration.

[0068] The calibration method of the high-precision and high-reliability drive shafting device for space, the specific steps of ground calibration are as follows:

[0069] S1. Install the high-precision and high-reliability drive shafting device for space on one side of the support bracket 16, and install the high-precision calibration sensor 14 on the other side of the support bracket 16;

[0070] S2. Use the information processing unit to read the preload value of the support bearing assembly 10 in the current state. If it deviates from the design value, adjust the height of the outer spacer 2 so that the preload meets the design value requirement.

[0071] S3. The information processing unit rotates the high-precision and high-reliability drive shaft device according to the set rotation step and stabilizes it at the current position. The angle value fed back by the high-precision and high-reliability drive shaft device itself and the feedback value of the ground high-precision calibration sensor 14 are compared and the difference is corrected. The correction points are curve fitted for all the correction points after one rotation and loaded into the information processing unit as the accuracy improvement compensation curve.

[0072] The calibration method for the high-precision and high-reliability drive shaft system for space applications, and the specific steps for on-orbit calibration are as follows:

[0073] S1. The high-precision and high-reliability drive shaft system for space rotates according to the specified step size. After stabilization, the feedback value of the sensor component 11 is compared and corrected with the detection value of the star sensor.

[0074] S2. Perform curve fitting on all correction points within one lap and load them into the information processing unit to compensate for errors in the entire lap position and improve accuracy.

[0075] The embodiments of the present invention described above are merely illustrative of the invention. These embodiments were selected and specifically described to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize it. The embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification, and all of these fall within the scope of protection of the present invention.

Claims

1. A high-precision, high-reliability drive shaft system for space applications, characterized in that, From right to left, it includes a support bearing assembly (10), a sensor assembly (11), a reducer (12), and a drive motor (13). A reducer (12) is installed between the support bearing assembly (10) and the drive motor (13) to achieve low-speed, high-torque output characteristics; The sensor assembly (11) is highly integrated within the structural components and is installed at the output end of the reducer (12); The support bearing assembly (10) includes a labyrinth seal cap (1), a spacer, a bearing housing (3), a bearing, a spindle (5), a disc spring (6), and a lock nut (9). The bearing includes a lower bearing (4) and an upper bearing (8). The lower bearing (4) and the upper bearing (8) are installed back to back to increase the bearing span and improve the bearing capacity of the shaft assembly. The inner ring of the bearing is a rotating part that is precisely fitted with the spindle (5), and the outer ring of the bearing is a stationary part that is precisely fitted with the bearing housing (3). The end of the spindle (5) is axially fixed to the shaft system by a lock nut (9) to prevent the bearing from axially loosening and falling off the load; The spacer includes an outer spacer (2) and an inner spacer (7), which are installed between the upper bearing (8) and the lower bearing (4); the bearing is preloaded axially by adjusting the height difference of the spacers; The disc spring (6) is installed between the root end face of the spindle (5) and the lower bearing (4), which can effectively prevent the active section from being overloaded by impact. The labyrinth sealing cap (1) is installed on the outer end face of the bearing seat (3) to axially position the outer ring of the bearing; The stress plates (17) are attached to four positions on the inner surface of the outer spacer (2) as preload measuring elements; The matching calibration device is a ground calibration device; the ground calibration device includes, from left to right, a high-precision calibration sensor (14), a connecting bracket (15), a supporting bracket (16) and the space high-precision and high-reliability drive shaft system device; the high-precision calibration sensor (14) has an accuracy better than 1″; the space high-precision and high-reliability drive shaft system device and the high-precision calibration sensor (14) are rigidly connected, which can calibrate the 360° position accuracy of the space high-precision and high-reliability drive shaft system device and send the position error to the information processing unit for error compensation; or The supporting calibration device is an on-orbit calibration device, which includes a high-precision and high-reliability drive shaft system for space use and a star sensor; the star sensor is an essential angle measuring device for satellites, and works in conjunction with the Hall effect switch to complete on-orbit calibration.

2. The high-precision, high-reliability drive shaft system for space applications as described in claim 1, characterized in that, The sensor assembly (11) includes a linear Hall effect sensor, a switch Hall effect sensor, a magnetic ring, and a setting device; the magnetic field distribution of the magnetic ring in space is complex, and the magnetic field vector is a spatial vector.

3. The high-precision, high-reliability drive shaft system for space applications as described in claim 2, characterized in that, The tuning device tunes the magnetic field distribution of the magnetic ring in space, increases the intensity and sinusoidality of the radial magnetic field, effectively reduces the ineffective tangential magnetic field component, and improves the detection accuracy of the position sensor.

4. The high-precision, high-reliability drive shaft system for space applications as described in claim 2, characterized in that, The linear Hall effect sensors are arranged in four orthogonal channels, evenly spaced at 90-degree intervals. By differentially dividing the linear Hall effect signals, the signal's anti-interference capability and compensation for installation errors can be ensured.

5. A high-precision, high-reliability drive shaft system for space applications as described in claim 2, characterized in that, The Hall effect switch is multi-channel and installed at other angles in space, enabling on-orbit calibration and compensation of position errors detected by linear Hall effect sensors.

6. The calibration method for a high-precision, high-reliability drive shaft system for space applications as described in claim 1, characterized in that, When the matching calibration device is a ground calibration device, the specific steps of the calibration method are as follows: S1. Install a high-precision and high-reliability drive shaft system on one side of the support bracket (16), and install a high-precision calibration sensor (14) on the other side of the support bracket (16); S2. Use the information processing unit to read the preload value of the support bearing assembly (10) in the current state. If there is a deviation from the design value, adjust the height of the outer spacer (2) so that the preload meets the design value requirement. S3. Using the information processing unit, rotate the high-precision and high-reliability drive shaft device according to the set rotation step and stabilize it at the current position. Compare the angle value fed back by the high-precision and high-reliability drive shaft device itself with the feedback value of the ground high-precision calibration sensor (14), correct the difference, and perform curve fitting on all correction points after one rotation. Load the curve into the information processing unit as a precision improvement compensation curve.

7. The calibration method for a high-precision, high-reliability drive shaft system for space applications as described in claim 1, characterized in that, When the matching calibration device is an on-orbit calibration device, the specific steps of the calibration method are as follows: S1. The high-precision and high-reliability drive shaft system device for space rotates according to the specified step size. After stabilization, the feedback value of the sensor assembly (11) is compared and corrected with the detection value of the star sensor. S2. Perform curve fitting on all correction points within one lap and load them into the information processing unit to compensate for errors in the entire lap position and improve accuracy.

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