A direct-drive precision optical turntable

Abstract

This invention belongs to the field of radio frequency and laser equipment, specifically relating to a direct-drive precision optical turntable. It includes a fixed support, within which a hollow shaft is housed. The shaft is rotatably connected to the fixed support via bearings, allowing the shaft to rotate along the central axis of the fixed support. A lens assembly is located at the top of the shaft. The fixed support has a drive assembly connected to the outer surface of the shaft for driving its rotation. A temperature control assembly is located within the fixed support, comprising a cover at the top of the fixed support, a temperature controller on the cover for heating or cooling, a sensor inside the cover for acquiring its temperature, and a controller at the bottom of the fixed support for controlling the temperature controller. This invention effectively ensures the rotational accuracy and reliability of the optical turntable under both low and high temperature conditions by controlling the temperature of the turntable's sealing and transmission components.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency and laser equipment, and specifically relates to a direct-drive precision optical turntable. Background Technology

[0002] Turntable systems play a crucial role in modern industry and product design. They are widely used in various equipment and mechanical systems, primarily functioning to support and rotate other parts, enabling relative movement between different components. A turntable system mainly consists of a fixed support, a rotating shaft, a drive system, and seals. Bearings support the fixed support and the shaft, while a contact-type dynamic seal prevents water and air from entering the turntable by compressing the seal. Turntable seals are primarily made of plastic and rubber. Under low-temperature conditions, significant dimensional changes occur, substantially increasing shaft rotation resistance and affecting control stability. Simultaneously, higher pressure accelerates seal wear, reducing system reliability. For high-precision turntables, both low and high temperatures affect the fit dimensions of precision components such as the shaft, bearings, and support, reducing transmission accuracy. Excessively low temperatures can drastically increase system resistance or even cause jamming. Therefore, precision optical turntables are difficult to use in complex outdoor conditions, especially in low-temperature frost conditions where they are almost impossible to operate.

[0003] To overcome the rotational resistance at low temperatures, multi-stage gear reducers are commonly used. However, this structure occupies a large space, is difficult to assemble, and its accuracy deteriorates after long-term wear. Furthermore, it is difficult to solve the problems of jamming due to frost at low temperatures and loss of accuracy at high temperatures. Summary of the Invention

[0004] The present invention provides a direct-drive precision optical turntable to solve the problems existing in the prior art. The turntable includes a fixed support, a hollow shaft inside the fixed support, and the shaft is rotatably connected to the fixed support via bearings, so that the shaft can rotate along the central axis of the fixed support. A lens assembly is provided on the top of the shaft. A drive assembly is provided inside the fixed support and connected to the shaft for driving the shaft to rotate.

[0005] The fixed support is equipped with a temperature control component, which includes:

[0006] The cover is located on the top of the fixed support, and one side of its cross-section is inverted L-shaped. The bearing mounting surface of the cover is in contact with the bearing. A sealing assembly is provided between the cover and the shaft.

[0007] A sealing pressure plate is disposed on the upper part of the shell cover and presses the sealing ring tightly;

[0008] A thermostat, which is attached to the housing cover and connected to the controller, can heat or cool the housing cover;

[0009] A sensor, which is disposed inside the housing and connected to the controller, is used to acquire the temperature of the housing.

[0010] The controller, located at the lower part of the fixed support, is capable of receiving temperature information from the sensor and controlling the temperature controller to heat or cool down.

[0011] Furthermore, the temperature controller includes a heating film attached to the temperature control mounting surface of the housing cover and is connected to the controller via a temperature control power supply harness; the sensor's sensing head is disposed in the inner hole of the housing cover and is connected to the controller via a sensing harness.

[0012] Furthermore, the cover is made of a high thermal conductivity material; a heat-insulating coating is applied to the mating surface between the cover and the fixed support, the non-installation surface of the cover, and the outer surface of the sealing plate.

[0013] Furthermore, the sealing assembly also includes a water-retaining ring disposed above the housing cover. The water-retaining ring is formed by or integrally disposed with the sealing pressure plate. The water-retaining ring cooperates with the top of the shaft to form a labyrinth sealing structure. In addition, the sealing ring is disposed on the sealing mounting surface of the housing cover and is pressed by the sealing pressure plate.

[0014] Furthermore, the lens assembly includes a lens bracket fixed to the top of the shaft, and the lens bracket is provided with a reflector and a window mirror, with the reflector and the window mirror forming an adjustable angle.

[0015] Furthermore, the drive assembly includes a motor stator fixed on a fixed support and a motor rotor fixed on a shaft; the controller drives the motor stator to drive the motor rotor based on the real-time position information of the shaft fed back by the encoder, thereby causing the shaft to rotate to a set position.

[0016] Furthermore, the controller can be connected to other turntables via control wiring harnesses to achieve synchronous control of multiple turntables or linkage control of multi-joint turntables.

[0017] Furthermore, there are two bearings, and locking nuts are provided below the two bearings for adjusting the clearance between the bearings.

[0018] Furthermore, the controller is used to control the thermostat to heat the shell cover when the temperature received from the sensor is lower than the lower limit of the preset temperature range; and to control the thermostat to stop heating when the temperature is higher than the upper limit of the preset temperature range.

[0019] A temperature control method for a direct-drive precision optical turntable includes the following steps:

[0020] Temperature monitoring steps: The current temperature information of the housing is acquired in real time and fed back to the controller through a sensor installed inside the housing.

[0021] Judgment and control steps: The controller compares the received current temperature information with the preset operating temperature range. When the current temperature is detected to be lower than the lower limit of the preset operating temperature range, the controller drives the temperature controller attached to the shell to heat up. When the current temperature is detected to be higher than the upper limit, the controller stops heating.

[0022] Heat conduction step: The heat generated by the temperature controller is conducted to the bearing and sealing ring through the housing cover to maintain its operating temperature within the preset operating temperature range.

[0023] This invention effectively controls the rotational resistance of the shaft in low-temperature environments by heating and temperature-controlling the bearings and seals, thereby improving system stability and reliability. The turntable of this invention adopts a direct-drive motor solution, reducing system space requirements and assembly difficulty, avoiding wear on the transmission chain, and ensuring the rotational accuracy of the turntable during long-term operation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the internal structure of the present invention;

[0025] Figure 2 This is a partial enlarged view of the connection between the shaft and the fixed support of the present invention;

[0026] Figure 3 This is a three-dimensional exploded view of the sealing temperature control component in this invention;

[0027] Figure 4 This is a flowchart of the control logic of the temperature control system in this invention;

[0028] Figure 5 The diagram shows the operating current test of the pitch axis under normal temperature conditions.

[0029] Figure 6 This is a test diagram of the rotational position error of the pitch axis under normal operating conditions.

[0030] Figure 7 The diagram shows the operating current test of the lower shaft under normal temperature conditions.

[0031] Figure 8 This is a test diagram of the rotational position error of the lower shaft under normal operating conditions;

[0032] Figure 9 The graph shows the change in the motor's drive current when the heating is off at a low temperature of -40℃.

[0033] Figure 10 The diagram shows the operating current of the pitch axis after heating at -40℃ for 10 minutes.

[0034] Figure 11 The diagram shows the rotational position error of the pitch axis after heating at -40℃ for 10 minutes.

[0035] Figure 12 The diagram shows the operating current of the azimuth axis after heating at -40℃ for 10 minutes.

[0036] Figure 13 The diagram shows the rotational position error of the azimuth axis after heating at -40℃ for 10 minutes.

[0037] Figure 14 The diagram shows the operating current of the pitch axis after heating at -40℃ for 40 minutes.

[0038] Figure 15 The diagram shows the rotational position error of the pitch axis after heating at -40℃ for 40 minutes.

[0039] Figure 16 The diagram shows the operating current of the azimuth axis after heating at -40℃ for 40 minutes.

[0040] Figure 17 The diagram shows the rotational position error of the azimuth axis after heating at -40℃ for 40 minutes.

[0041] The names of the components labeled in the diagram are as follows:

[0042] 1. Shaft; 2. Fixed support; 3. Housing cover; 4. Sealing ring; 5. Sealing pressure plate; 6. Bearing; 7. Locking nut; 8. Motor; 9. Encoder; 10. Controller; 11. Temperature controller; 12. Sensor; 13. Heat insulation coating; 14. Lens bracket; 15. Reflector; 16. Window mirror; 101. Shaft outer surface; 301. Temperature controller mounting surface; 302. Inner hole; 303. Bearing mounting surface; 304. Sealing plate Surface mounting surface; 305, pressure plate mounting surface; 401, outer sealing surface; 402, inner sealing surface; 501, outer surface of pressure plate; 801, motor rotor; 802, motor stator; 803, motor wiring harness; 901, encoder rotor; 902, encoder stator; 903, encoder wiring harness; 1001, control wiring harness; 1101, temperature control board; 1102, temperature control wiring harness; 1201, sensing head; 1202, sensor wiring harness. Detailed Implementation

[0043] The invention will now be further described with reference to the accompanying drawings.

[0044] Example 1:

[0045] This embodiment provides a direct-drive precision optical turntable, such as Figure 1 and Figure 2As shown, the assembly includes a fixed support 2, within which a hollow shaft 1 is housed. The shaft 1 is rotatably connected to the fixed support 2 via two bearings 6, allowing the shaft 1 to rotate along the central axis of the fixed support 2. Locking nuts 7 are located below the two bearings 6. By adjusting the position of the locking nuts 7 on the shaft 1, the clearance of the bearings 6 can be adjusted, and the axial movement of the shaft 1 relative to the bearings 6 can be restricted, thereby ensuring the assembly accuracy of the shaft 1.

[0046] like Figure 3 As shown, a temperature control assembly housing 3 is installed above the gap between the shaft 1 and the fixed support 2, with one side of its cross-section being an inverted L-shape. The bearing mounting surface 303 on the inner side of the vertical wall of the housing 3 contacts the bearing 6 to achieve heat conduction. A sealing assembly is provided between the transverse wall of the housing 3 and the shaft 1, which includes a sealing ring 4 and a sealing pressure plate 5 (which also serves as a water-blocking ring). Specifically, the sealing ring 4 is disposed on the sealing mounting surface 304 of the housing 3; the sealing pressure plate 5 is disposed on the pressure plate mounting surface 305 of the housing 3 and presses the sealing ring 4 downward, restricting its movement relative to the housing 3. At the same time, the inner sealing surface 402 of the sealing ring 4 is tightly fitted with the outer circular surface 101 of the shaft 1 to form a dynamic seal, which can prevent moisture from entering the turntable. In addition, the top of the shaft 1 is provided with an outer convex ring and a sealing groove, and the sealing pressure plate 5 is provided with a protrusion that inserts into the sealing groove. The two work together to form a labyrinth seal structure, which can further prevent rainwater from entering.

[0047] In terms of temperature control, the cover 3 is equipped with a temperature controller 11 and a sensor 12. The temperature controller 11 includes a heating film (marked as 1101) attached to the temperature control mounting surface 301 of the cover 3 for heating the cover 3; the sensor 12 has a sensing head 1201 disposed in the inner hole 302 of the cover 3, which can monitor and provide feedback on the internal temperature of the cover 3 in real time.

[0048] Under low-temperature conditions, sensor 12 feeds back temperature data to controller 10. When the feedback value is lower than the preset lower limit, controller 10 drives temperature controller 11 to work through temperature control wiring harness 1102. The housing 3 is made of a high thermal conductivity material, which can quickly transfer heat to the bearing mounting surface 303 and the sealing mounting surface 304, thereby maintaining the normal operating temperature of bearing 6 and sealing ring 4.

[0049] To reduce heat loss, a heat-insulating coating 13 is applied to the non-mounting surface of the cover 3 and the outer surface 501 of the sealing plate 5.

[0050] The drive assembly in this embodiment includes a motor stator 802, a motor rotor 801, an encoder stator 902, and an encoder rotor 901. The motor stator 802 and encoder stator 902 are fixed inside the fixed support 2; the motor rotor 801 and encoder rotor 901 are fixed to the outer wall of the shaft 1 and rotate synchronously with the shaft 1. The controller 10 receives angle information fed back from the encoder via the encoder harness 903, and drives the motor stator 802 via the motor harness 803, using electromagnetic force to drive the motor rotor 801, thereby achieving high-precision rotation of the shaft 1.

[0051] The lens assembly at the top of the shaft 1 includes a lens holder 14 fixed to the top of the shaft, on which a reflector 15 and a window mirror 16 are mounted. The reflector 15 is tilted, forming an adjustable angle between its top and the window mirror 16. The incident light beam passes through the hollow interior of the shaft 1, is reflected by the reflector 15, and exits through the window mirror 16. By changing the angle of the reflector 15, multi-angle scanning of the light beam can be achieved.

[0052] Example 2:

[0053] This embodiment aims to verify the effectiveness of the temperature control component in ensuring the rotational accuracy of the turntable under extreme temperature environments. The verification process and control logic are as follows: Figure 4 As shown. A two-axis scanner-type turntable was selected as the test object, and independent tests were performed on the pitch and azimuth axes respectively. The specific verification process is as follows:

[0054] 1. Experimental Environment Setup

[0055] The direct-drive precision optical turntable described in this embodiment was placed in a high and low temperature test chamber and connected to an external computer using a wiring harness. The turntable was controlled in real time by the host computer, and the controller data was exported. Two key monitoring indicators were selected for this experiment: one is the motor drive current, which can indirectly reflect the magnitude of the rotational resistance; the other is the motion position error, which is used to reflect the rotational accuracy (1 cnt corresponds to an angular resolution of 360° / 131072).

[0056] 2. Standard test at room temperature (25℃)

[0057] First, the turntable was functionally tested under normal temperature conditions to establish baseline data.

[0058] For the pitch axis, such as Figure 5 As shown, its maximum operating current is 1.29A; Figure 6 As shown, its motion position error remains stable within the range of -3cnt to 3cnt.

[0059] For the azimuth axis, such as Figure 7 As shown, its maximum operating current is 1.48A; Figure 8As shown, its motion position error remains stable within the range of -4cnt to 4cnt.

[0060] The above data shows that the internal resistance of the turntable is small at room temperature, and the accuracy fully meets the design requirements.

[0061] 3. Low-temperature failure reproduction (-40℃)

[0062] The high and low temperature chamber temperature was lowered to -40℃ and maintained for 12 hours, during which the turntable was powered off. After the heat preservation was completed, the power was turned on directly, but the temperature control components were not turned on at this time.

[0063] Tests revealed a sharp increase in frictional resistance on both the pitch and azimuth axes, exceeding the motor's drive torque. For example... Figure 9 As shown, the drive current surged to over 7A, the motor failed to rotate normally, and the system was stuck. This phenomenon confirms that low temperatures cause the seals to harden and the clearance to shrink, severely hindering the turntable's operation.

[0064] 4. Temperature control performance verification (heating started at -40℃)

[0065] Maintaining the ambient temperature at -40°C, the temperature control component described in this invention is activated. After receiving feedback from the sensor, the controller drives the heating element to continuously heat the housing cover.

[0066] Phase 1: Heating for 10 minutes test

[0067] The first test was conducted after heating for 10 minutes.

[0068] For the pitch axis, the motor has resumed rotation, as... Figure 10 As shown, its maximum operating current drops to 2.97A; Figure 11 As shown, its motion position error ranges from -17 cmt to 18 cmt.

[0069] For the azimuth axis, the motor also resumes rotation, such as Figure 12 As shown, its maximum operating current drops to 3.80A; Figure 13 As shown, its motion position error ranges from -23 cmt to 24 cmt.

[0070] The results showed that short-term heating successfully released the jammed state, but the rotational resistance was still higher than the room temperature level, and the accuracy had not yet returned to its optimal state.

[0071] Phase Two: Heating for 40 minutes test

[0072] Continue heating for 40 minutes before conducting a second test.

[0073] For the pitch axis, such as Figure 14As shown, the maximum operating current has been further reduced to 1.78A, a value very close to 1.29A at room temperature; Figure 15 As shown, the motion position error converges to -8cnt to 7cnt.

[0074] For the azimuth axis, such as Figure 16 As shown, the maximum operating current is reduced to 2.32A; Figure 17 As shown, the motion position error converges to -10cnt to 10cnt.

[0075] This indicates that as the heating time increases, the heat has been fully conducted to the inside of the bearing and seal, resulting in a significant reduction in rotational resistance and a significant improvement in rotational accuracy, which is close to the room temperature level.

[0076] 5. Experimental Conclusions

[0077] The comparative experiments described above demonstrate that the temperature control component of this invention effectively solves the problem of turntable jamming caused by hardening of seals and material shrinkage at temperatures as low as -40°C. By heating the housing, bearings, and sealing components, the system can restore rotational resistance and control accuracy to near-normal temperatures in just about 40 minutes, thereby ensuring the reliable operation of the precision optical turntable in extreme low-temperature environments.

[0078] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A direct-drive precision optical turntable, comprising a fixed support (2), wherein a hollow shaft (1) is provided inside the fixed support (2), the shaft (1) and the fixed support (2) are rotatably connected by a bearing (6), so that the shaft (1) can rotate along the central axis of the fixed support (2); a lens assembly is provided on the top of the shaft (1); a drive assembly is provided inside the fixed support (2), connected to the shaft (1), for driving the shaft (1) to rotate, characterized in that: The fixed support (2) is equipped with a temperature control component, which includes: The cover (3) is located on the top of the fixed support (2), and one side of its cross section is inverted L-shaped. The bearing mounting surface (303) of the cover (3) is in contact with the bearing (6). A sealing assembly is provided between the cover (3) and the shaft (1). Sealing plate (5), the sealing plate (5) is set on the upper part of the shell cover (3) and presses the sealing ring (4). Thermostat (11) is attached to the cover (3) and connected to the controller (10), and can heat or cool the cover (3); Sensor (12), which is disposed inside the cover (3) and connected to the controller (10), is used to obtain the temperature of the cover (3); The controller (10) is located at the lower part of the fixed support (2), and can receive temperature information from the sensor (12) and control the thermostat (11) to heat or cool down.

2. The direct-drive precision optical turntable according to claim 1, characterized in that: The temperature controller (11) includes a heating film (1101) pasted on the temperature control mounting surface (301) of the cover (3) and connected to the controller (10) through a temperature control power supply harness (1102); the sensing head (1201) of the sensor (12) is disposed in the inner hole (302) of the cover (3) and connected to the controller (10) through a sensing harness (1202).

3. The direct-drive precision optical turntable according to claim 2, characterized in that: The shell cover (3) is made of a high thermal conductivity material; A heat-insulating coating (13) is applied to the mating surfaces of the cover (3) and the fixed support (2), the non-installation surfaces of the cover (3), and the outer surface (501) of the sealing pressure plate (5).

4. The direct-drive precision optical turntable according to claim 1, characterized in that: The sealing assembly also includes a water-blocking ring disposed above the shell cover (3). The water-blocking ring is formed by or integrally disposed with the sealing pressure plate (5). The water-blocking ring and the top of the shaft (1) cooperate to form a labyrinth sealing structure. Furthermore, the sealing ring (4) is disposed on the sealing mounting surface (304) of the shell cover (3) and is pressed by the sealing pressure plate (5).

5. A direct-drive precision optical turntable according to claim 1, characterized in that: The lens assembly includes a lens bracket (14) fixed to the top of the shaft (1), and a reflector (15) and a window mirror (16) are provided on the lens bracket (14). The reflector (15) and the window mirror (16) form an adjustable angle.

6. The direct-drive precision optical turntable according to claim 1, characterized in that: The drive assembly includes a motor stator (802) fixed on a fixed support (2) and a motor rotor (801) fixed on a shaft (1); the controller (10) drives the motor stator (802) to drive the motor rotor (801) based on the real-time position information of the shaft (1) fed back by the encoder (9), thereby causing the shaft (1) to rotate to a set position.

7. A direct-drive precision optical turntable according to claim 6, characterized in that: The controller (10) can be connected to other turntables via the control harness (1001) to achieve synchronous control of multiple turntables or linkage control of multiple joint turntables.

8. A direct-drive precision optical turntable according to claim 1, characterized in that: There are two bearings (6), and a locking nut (7) is provided below the two bearings (6) to adjust the clearance between the bearings (6).

9. A direct-drive precision optical turntable according to any one of claims 1, characterized in that: The controller (10) is used to control the temperature controller (11) to heat the shell cover (3) when the temperature fed back by the sensor (12) is lower than the lower limit of the preset temperature range; and to control the temperature controller (11) to stop heating when the temperature is higher than the upper limit of the preset temperature range.

10. A temperature control method for a direct-drive precision optical turntable as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Temperature monitoring steps: The current temperature information of the cover (3) is acquired in real time and fed back to the controller (10) by the sensor (12) set in the cover (3); Judgment and control steps: The controller (10) compares the received current temperature information with the preset working temperature range. When the current temperature is detected to be lower than the lower limit of the preset working temperature range, the controller (11) attached to the shell cover (3) is driven to heat. When the current temperature is detected to be higher than the upper limit, the heating is stopped. Heat conduction step: The heat generated by the thermostat (11) is conducted through the housing (3) to the bearing (6) and the sealing ring (4) to maintain its operating temperature within the preset operating temperature range.

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