An axial support system for an astronomical telescope mirror

Abstract

The present invention discloses an axial support system for an astronomical telescope mirror, comprising a force sensor, a flexible member, a connecting rod assembly, a fixed structural member, a counterweight, and may further comprise a force actuator. When the present invention realizes passive support of the mirror, the passive support of the mirror is not limited by the number of supports and the position of supports, and no additional lateral force will act on the mirror. A large-scale force scaling can be achieved, and the shape and center of gravity position of the counterweight do not affect the amplification factor of the output force. When the present invention realizes active and passive integrated support of the mirror, the passive force part does not need to be controlled by a control system, and the force actuator for correcting the mirror surface shape only needs to provide the stroke range required by the correction force, without the need to superimpose the support force of the gravity part of the mirror body. The passive force generated by the counterweight, the active force of the force actuator, and the final output force of the mirror axial support system are coaxial, which can prevent the axial support system from accidentally generating a radial force on the mirror body, thereby ensuring the accuracy of the correction force required for correcting the mirror surface shape.

Description

Technical Field

[0001] The invention relates to an axial support system for an astronomical telescope mirror, which is mainly used for supporting a thick mirror of an astronomical telescope when there is no main driving force part, and is mainly used for axially supporting a large-aperture thin mirror when there is a main driving force part. Background Art

[0002] Astronomical telescope mirror support systems are generally divided into two types: passive support and active support.

[0003] Passive supports are primarily used in applications where the mirror's diameter-to-thickness ratio is relatively small. For primary mirrors with apertures under 2.5 meters and a diameter-to-thickness ratio less than 10, passive supports are typically used for axial support. The purpose of a passive mirror support is to support the mirror so that the supported mirror's surface error meets the design requirements of the telescope's optical system. Typically, the root mean square error (RMS) of the mirror's surface shape should meet the requirement of at least one-thirtieth of a wavelength, or even higher. Maintaining the mirror's shape after machining places high demands on the passive mirror support system. Currently, two main types of passive support systems are used for astronomical telescope mirrors: Whiffle-tree supports and passive counterweight supports. Whiffle-tree supports are widely used for passive support of small-diameter mirrors. Through the automatic adjustment of levers within the Whiffle-tree support structure, they effectively provide axial support for the mirror. Whiffle-tree support design is closely related to the number of support points. As the number of support points increases, the Whiffle-tree support structure becomes more complex, with more layers. Therefore, Whiffle-tree structures are generally not used for supporting large-diameter mirrors. Even for smaller mirrors with lightweight backing, Whiffle-tree structures are not suitable. Counterweight passive supports, on the other hand, can accommodate multiple support points. Even for lightweight mirrors, the placement of support points can be easily adjusted to achieve support. However, conventional counterweight passive supports utilize a lever-amplified counterweight force, similar to a seesaw. A drawback of this type of lever is that the counterweight force, amplified by the lever, can easily generate lateral forces on the mirror surface. This will affect the mirror support effect and deteriorate the mirror surface quality.

[0004] Active optics technology primarily corrects mirror surface errors caused by manufacturing, installation, gravitational fields, and temperature gradients. For nearly three decades, active optics has been widely used in ground-based telescopes. Active optical mirror support systems are a key technology in the design of large-aperture telescopes. For thin mirrors with an aperture of less than two meters or large-aperture primary mirrors, the mirror mass is relatively low. With multi-point active support, the output force at each support point typically ranges from -200N to +200N. Therefore, active actuators are typically used. These actuators come in four main types: electromechanical, hydraulic, pneumatic, and piezoelectric. When the required output force exceeds 1000N, electromechanical actuators require significantly larger design dimensions. Hydraulic and pneumatic actuators require increased oil or air pressure, or higher output force can be achieved by increasing the cross-sectional area of ​​the cylinder. Increasing the cross-sectional area of ​​an oil or air cylinder also increases the size of the actuator. Increasing the oil or air pressure is prone to oil or air leakage. Both hydraulic and pneumatic actuators suffer from the problem of the actuator's output force being zero when the power is off. While piezoelectric actuators offer the advantages of high precision and high frequency, they struggle with low stroke and the lack of output force when the power is off. When using an active-only actuator to support a mirror, the active force should include both the mirror's own weight and the correction force required to correct the mirror's shape. Therefore, an active-only actuator is not suitable for axial support of a single large-aperture lens. The primary axial support force for a single large-aperture lens is used to balance the mirror's own weight (passive support force), while the active correction force (active support force) used to correct the mirror's shape accounts for approximately one-third or less of the total output force. Therefore, to reduce the design complexity of the actuator, the passive support force is typically separated from the active correction force. Specifically, the passive support force balances the gravity required along the optical axis at different telescope pointing angles. The active correction force, on the other hand, adjusts the mirror's surface shape errors at different pointing angles. For example, the 8-meter primary mirror support at the European Southern Observatory's Very Large Telescope (VLT) utilizes a combination of hydraulic passive support and electromechanical actuators to achieve a passive-active actuator design. In actual operation, as the telescope's pointing angle changes, the hydraulic pressure required to balance the gravity force in the mirror's axial support also changes, requiring manual control of the pressure in the hydraulic system providing the passive force. The active correction force required to correct the mirror's surface shape errors also needs to be adjusted via a control system. Consequently, this passive-active support actuator requires two control systems: one for controlling the oil pressure and one for active correction control of the mirror's surface shape. This increases the complexity of the control system, and the hydraulic system must remain powered and provide oil pressure at all times.Another passive-active solution uses only a counterweight. The counterweight consists of two parts: one fixed weight balances the mirror's gravity, while the other is adjusted by a motor-driven screw, thereby changing the lever's power arm and adjusting the actuator's output force to correct the mirror's surface shape errors. For example, the European Southern Observatory's New Technology Telescope (NTT) has a drawback: the lever-based output force easily generates both axial and lateral forces, compromising the ability to actively correct the mirror's surface shape. Summary of the Invention

[0005] In response to the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide an axial support system for the mirror of an astronomical telescope. This system can not only meet the requirements of multi-point axial passive support, but also avoid the lateral force on the mirror surface that is easily generated by the gravity of the counterweight after being amplified by the lever when supporting the mirror surface. Although it still adopts the passive counterweight support form, the arrangement of the lever is changed to achieve that the final output force of the passive support only exists in the axial force perpendicular to the bottom surface of the mirror surface. This system reduces the adjustment range of the main power part and only controls the main power in the axial support. Even when the main power part is not working, the mirror surface shape can still be well guaranteed. When the force actuator is powered off, its structure can self-lock to ensure the stability of the output force, thereby reducing the energy consumption of the force actuator and reducing the impact of the heating of the actuator on the seeing inside the telescope dome. The system has a simple structure and high adjustment accuracy.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An axial support system for an astronomical telescope mirror comprises a force sensor, a flexible member, a connecting rod assembly, a fixed structural member, and a counterweight. The output force end of the force sensor is arranged on the output force axis of the axial support system and is connected to the mirror. The connecting rod assembly comprises a first force transmission rod, a second force transmission rod, and a third force transmission rod. The first force transmission rod and the second force transmission rod are hinged through a first hinge point, and the second force transmission rod and the third force transmission rod are hinged through a second hinge point. The force sensor is hinged to the first force transmission rod through a flexible member, and the third force transmission rod is hinged to the counterweight through a third hinge point. The third hinge point is away from the mirror chamber relative to the second hinge point, so that The angle between the third force transmission rod and the second force transmission rod is less than 90°, so that the gravity of the counterweight can be amplified and output in the reverse direction as the source power of passive support. The rod body of the second force transmission rod between the first hinge point and the second hinge point is hinged to the fixed structure through the fourth hinge point. The fixed structure is fixed to the mirror chamber. The counterweight is arranged along the output force axis and is located in the internal space formed by the upper fixed structure, the lower mirror chamber, and the circumferential multiple connecting rod assemblies. The circumferential multiple connecting rod assemblies ensure that the source power is coaxial with the final output force while amplifying the source power. The counterweight is installed on the mirror chamber through a vertical guide mechanism.

[0008] Furthermore, it also includes a force actuator, which is vertically fixed on the fixed structure, and the output end of the force actuator faces the balance weight and is connected to the balance weight.

[0009] Furthermore, the length of the second force transmission rod between the first hinge point and the fourth hinge point is smaller than the length of the second force transmission rod between the second hinge point and the fourth hinge point.

[0010] Furthermore, a base is fixedly mounted on the mirror chamber, and the fixed structural member and the vertical guide mechanism are both fixedly mounted on the base.

[0011] Furthermore, the fixed structure is connected to the base through a plurality of vertical connecting rods.

[0012] Furthermore, the vertical guide mechanism includes a linear bearing sleeve and a guide shaft. A groove is provided at the bottom of the balancing weight, and the linear bearing sleeve is installed in the groove. One end of the guide shaft is fixed, and the other end is sleeved in the linear bearing sleeve. The balancing weight can slide freely on the guide shaft using the linear bearing sleeve.

[0013] Furthermore, the output force end of the force sensor is connected to the mirror surface via an Invar pad.

[0014] Furthermore, several sets of the axial support systems act together on the mirror surface to balance the gravity of the mirror body.

[0015] Furthermore, when the telescope points to the zenith, the balance weight tends to slide downward along the vertical guide mechanism due to its own gravity, and the gravity acts on one end of the second force transmission rod through the third force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes the force sensor vertically upward, thereby providing a vertical upward support force on the mirror surface; when the telescope points to an angle with the zenith, the balance weight tends to slide downward along the guide mechanism. At this time, the gravity of the balance weight along the guide axis is converted into an axial force along the third force transmission rod, acting on one end of the second force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes the force sensor axially, thereby providing an upward support force perpendicular to the bottom of the mirror surface, and the final resultant force is exactly balanced with the gravity component of the mirror body along the optical axis.

[0016] Furthermore, when the telescope points to the zenith, the counterweight tends to slide downward along the vertical guide mechanism under the action of its own gravity, and the gravity acts on one end of the second force transmission rod through the third force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes the force sensor in the vertical upward direction, thereby exerting a vertical upward supporting force on the mirror surface; when the telescope points to an angle with the zenith, the counterweight tends to slide downward along the guide mechanism, and at this time, the gravity of the counterweight along the guide axis is converted into an axial force along the third force transmission rod, which acts on one end of the second force transmission rod, and is transmitted from the other end of the second force transmission rod. To the first force transmission rod, the resultant force of the circumferentially arranged first force transmission rods pushes the force sensor axially, thereby providing an upward supporting force perpendicular to the bottom of the mirror, and the final resultant force is just balanced with the gravity component of the mirror body along the optical axis; the passive supporting force of the axial support system on the mirror is realized; when the mirror surface error is large and does not meet the observation requirements during the observation process, the control force actuator outputs force to the balance weight, which acts on one end of the second force transmission rod through the third force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes or pulls the force sensor downward in the vertical upward direction; active correction of the mirror surface is realized.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] When the system of the present invention realizes passive support of the mirror surface, it will not be affected by the diameter of the mirror surface. When the diameter of the mirror surface is large, it is still convenient to arrange various passive supports. At the same time, even after the back of the mirror surface has been lightweighted, it is very convenient to use the system of the present invention for support. Four beneficial effects are achieved: First, the design of the passive support of the mirror surface is no longer limited by the number and position of supports; second, when realizing passive support of the mirror surface, no additional lateral force will be applied to the mirror surface; third, three groups of circumferentially evenly distributed force transmission rod force scaling mechanisms can achieve a large proportion of force scaling; fourth, the shape and center of gravity position of the passive counterweight will not affect the amplification factor of the output force, so the installation of the counterweight is extremely convenient.

[0019] When the system of the present invention realizes the active and passive integrated support of the mirror, its axial support force can be decomposed into two parts: the mirror body weight and the mirror surface correction force. The axial force for balancing gravity is separated from the active correction force, thereby achieving three beneficial effects: First, the passive part does not need to be controlled by the control system, reducing the design difficulty of the control system; second, the force actuator for correcting the mirror surface shape only needs to provide the stroke range required by the correction force, and there is no need to superimpose the support force of the mirror body weight part, thereby significantly reducing the power consumption of the support system; third, the main force of the force actuator and the final output force of the mirror axial support system are coaxial, thereby avoiding the axial support system from accidentally generating radial force on the mirror body, thereby ensuring the accuracy of the correction force required when correcting the mirror surface shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a diagram showing the working principle of the first embodiment when the telescope is pointed at the zenith;

[0021] Figure 2 is a diagram of the working principle of embodiment 1 when the telescope is pointed at other pointing angles;

[0022] Figure 3 This is a diagram showing the working principle of the second embodiment when the telescope is pointing to the zenith;

[0023] Figure 4 This is a diagram showing the working principle of the second embodiment when the telescope points to other pointing angles.

[0024] Markings in the figure: 1. Mirror; 2. Force sensor; 3. Flexible rod; 4. First force transmission rod; 5. Fixed structure; 6. Second force transmission rod; 7. Third force transmission rod; 8. Fixed structure connecting rod; 9. Base; 10. Guide shaft; 11. Linear bearing sleeve; 12. Balance weight; 13. Invar pad; 14. Force actuator; 15. Mirror chamber. DETAILED DESCRIPTION

[0025] The present invention will be described in further detail below with reference to the accompanying drawings.

[0026] Example 1

[0027] The axial support system for an astronomical telescope mirror of this embodiment is particularly suitable for passive support of a thick mirror of an astronomical telescope.

[0028] like Figure 1-2 As shown, the axial support system of an astronomical telescope mirror in this embodiment mainly includes a force sensor 2, a flexible member (a flexible rod 3 is preferably used in this embodiment to facilitate the transmission of axial force), a connecting rod assembly, a fixed structural member 5, and a counterweight 12. One end of the axial support system is connected to the supported mirror 1 through the force sensor, and the other end is fixed to the mirror chamber 15. The connecting rod assembly specifically includes a first force transmission rod 4, a second force transmission rod 6, and a third force transmission rod 7 that are hinged in sequence, wherein the first force transmission rod 4 and the second force transmission rod 6 are hinged at a first hinge point, the second force transmission rod 6 and the third force transmission rod 7 are hinged at a second hinge point, the output force end of the force sensor 2 is connected to the mirror 1 through an invar pad 13, the other end of the force sensor 2 is hinged to the first force transmission rod 4 through the flexible rod 3, one end of the third force transmission rod 7 is hinged to the second force transmission rod 6, and the other end is hinged to the counterweight 12 at a third hinge point, the third hinge point is far away from the mirror chamber 15 relative to the second hinge point, so that the angle between the third force transmission rod 7 and the second force transmission rod 6 is less than 90°, and the third hinge point is further away from the mirror chamber 15 than the second hinge point. The shaft of the second force transmission rod 6, between the first and second hinge points, is hinged to the fixed structure 5 via a fourth hinge point. To achieve a force amplification effect, in this embodiment, the length of the second force transmission rod 6 between the first and fourth hinge points is preferably set to be shorter than the length between the second and fourth hinge points. The fixed structure 5 is fixed to the mirror chamber 15. The counterweight 12 is located in the internal space formed by the upper fixed structure 5, the lower mirror chamber 15, and multiple circumferential connecting rod assemblies (in this embodiment, three connecting rod assemblies are preferably evenly distributed along the circumference). The counterweight 12 is mounted on the mirror chamber 15 via a vertical guide mechanism. The connecting rod assembly effectively converts the gravitational force exerted on the counterweight along the axial direction of the mirror surface into the axial support force exerted by the axial support system on the mirror surface. The multiple circumferential connecting rod assemblies amplify the source power while ensuring that the source power and the final output force are coaxial but opposite in direction. In this embodiment, a base 9 is preferably fixed to the mirror chamber 15, serving as the mounting base for the fixed structure 5, the vertical guide mechanism, and other components. In this embodiment, the vertical guide mechanism preferably includes a linear bearing sleeve 11 and a guide shaft 10. The bottom of the counterweight 12 is provided with a groove, and the linear bearing sleeve 11 is installed in the groove. One end of the guide shaft 10 is fixed to the fixed base 9, and the other end is sleeved in the linear bearing sleeve 11. The counterweight 12 can slide freely on the guide shaft 10 using the linear bearing sleeve 11. In this embodiment, the fixed structure 5 is connected to the base 9 by a plurality of (preferably three) fixed structure connecting rods 8.

[0029] like Figure 1As shown, when the telescope is pointed toward the zenith, the downward force of gravity causes the counterweight 12 to slide downward. The weight of the counterweight 12 acts on one end of the second force transmission rod 6 via the third force transmission rod 7, amplifying the force and outputting it to the first force transmission rod 4. The combined force of three circumferentially distributed groups of first force transmission rods 4 pushes the force sensor vertically upward, thereby providing a vertical upward support force on the mirror surface. In actual application, multiple sets of these axial support systems work together to automatically adjust the passive force at each pointing angle of the telescope to precisely balance the gravity of the mirror body, without the need for human intervention.

[0030] like Figure 2 As shown, when the telescope is pointing at an angle to the zenith, the balance weight 12 tends to slide downward along the guide shaft 10 due to the action of gravity. The gravity of the balance weight 12 is converted into the component force along the guide shaft 10, and the axial force of the third force transmission rod 7 acts on one end of the second force transmission rod 6. The force is amplified and output to the first force transmission rod 4. The resultant force of the three groups of evenly distributed first force transmission rods 4 in the circumferential direction pushes the force sensor along the axial direction of the actuator, and still realizes the upward supporting force perpendicular to the bottom of the mirror. The final resultant force is still just balanced with the gravity component force of the mirror body along the optical axis.

[0031] This embodiment provides an axial support system for an astronomical telescope mirror. One end is connected to the supported mirror via a force sensor, and the other end is fixed to the mirror chamber. The force output end of the axial support system is located on the output shaft of the passive support system. A counterweight is positioned along the output force axis. The counterweight is subjected to gravity, generating the source force for the passive support. This source force is amplified by a circumferentially distributed connecting rod assembly to achieve a high output force (the slave force). A force sensor is positioned at the force output end to directly reflect the actual output force of the passive support, ensuring the accuracy of the output force. This axial support system utilizes the gravity exerted on the counterweight, amplified by a force scaling mechanism, to precisely balance the gravity of the mirror body. As the pointing angle changes during telescope observation, the axial support system automatically adjusts the output passive force to consistently balance the axial gravity of the mirror body. The resultant passive force output is directed solely perpendicular to the axis of the mirror body's bottom surface, thereby preventing the actuator from exerting lateral forces on the mirror surface.

[0032] The source power of the axial support system is generated by a counterweight. This passive source power is used to balance the axial gravity of the mirror body itself. When the pointing angle of the telescope changes, the axial gravity of the mirror body changes accordingly. At this time, the axial support system can automatically change and still just balance the axial gravity of the mirror body, that is, the counterweight automatically adjusts as the pointing angle of the telescope changes, and can always achieve the requirement of balancing the gravity of the mirror body; the source power of the axial support system is coaxial with the final output force, but in opposite directions; the final output force of the axial support system is obtained by amplifying the source power through a circumferentially evenly distributed force transmission rod force scaling mechanism, so that a larger final output force can be achieved while providing a smaller counterweight weight, and ensuring that the final output force is only an axial force perpendicular to the mirror surface; the circumferentially evenly distributed force transmission rod force scaling mechanism realizes the reverse function of the source power, that is, converts the downward gravity into an upward support force on the mirror surface; the shape and center of gravity position of the counterweight of the axial support system will not affect the magnification of the force scaling mechanism; since the generation of the passive force is coaxial with the output direction, no lateral force will be generated on the mirror surface.

[0033] Example 2

[0034] The present embodiment provides an axial support system for an astronomical telescope mirror, which is an active-passive integrated support system with a precise force output function. The system is particularly suitable for use in a support system for a single-piece large-aperture active optical technology mirror of an astronomical telescope. The system provides axial support for large-aperture thin mirrors or lightweight mirrors where the overall weight of the mirror is still relatively large. At the same time, the active power part of the axial support system can be used to correct the mirror surface shape.

[0035] The structure of the axial support system of the astronomical telescope mirror in this embodiment is as follows: Figure 3-4As shown, its structure is similar to that of Example 1, differing from Example 1 in that a force actuator 14 (preferably an electromechanical permanent magnet force actuator) is added. Force actuator 14 is fixed to the fixed structure 5 via screws, and the output end of force actuator 14 is connected to the counterweight 12. This system converts the downward gravitational force of the counterweight hammer into an upward axial support force that balances the mirror's weight, and decomposes the axial support force required for the mirror into a passive force and an active force component. The passive force component, in the form of a counterweight hammer, is used to balance the mirror's own weight. The passive force component can automatically adjust the passive force to exactly balance the mirror's weight at all pointing angles of the telescope, without the need for human intervention. The passive force is output only in the axial direction, and its lateral resultant force is zero, thus preventing the actuator from exerting lateral forces on the mirror. The active force is used to correct the mirror shape. Since the active force is only used to correct the mirror shape and there is a connecting rod assembly, a lower output force range can be selected. The process of applying the active force by the force actuator does not change the magnitude of the passive force. Therefore, the applied active force is only used to correct the mirror shape error. The system's axially downward active force plus the passive force is ultimately converted into an axially upward supporting force. The passive force, active force, and final axial support system output force are always arranged coaxially. The final axial support system output force is synthesized and amplified by the passive force and the active force before output. The active force in this embodiment preferably uses an electromechanical permanent magnet force actuator.

[0036] like Figure 3 As shown, when the telescope is pointed toward the zenith, the downward force of gravity causes the counterweight 12 to slide downward. The weight of the counterweight 12 acts on one end of the second force transmission rod 6 through the third force transmission rod 7, amplifying the force and outputting it to the first force transmission rod 4. The combined force of three evenly distributed groups of third force transmission rods 4 pushes the force sensor vertically upward, thereby providing passive vertical support for the mirror surface. In actual applications, nearly one hundred or more sets of this axial support system work together to precisely balance the gravity of the telescope. When the mirror surface error is large and does not meet the observation requirements during the observation process and the mirror surface needs to be corrected, the electronic control system controls the force actuator 14 to output force to act on the balance weight 12. The force actuator 14 outputs force, which acts on one end of the second force transmission rod 6 through the third force transmission rod 7, amplifies the force and outputs it to the first force transmission rod 4. The combined force direction of the three groups of first force transmission rods 4 evenly distributed around the circumference pushes or pulls the force sensor vertically upward, thereby realizing the thrust or pull effect on the mirror surface and completing the active correction of the mirror surface.

[0037] like Figure 4As shown, when the astronomical telescope is pointing at an angle to the zenith, gravity causes the counterweight 12 to slide downward along the guide shaft 10. The weight of the counterweight 12, along the guide shaft 10, is converted into an axial force on the third force transmission rod 7, acting on one end of the second force transmission rod 6. This force is amplified by the lever principle and then output to the first force transmission rod 4. The combined force of three evenly distributed groups of first force transmission rods 4 pushes the force sensor axially on the actuator, still achieving an upward support force perpendicular to the bottom of the mirror. The resulting combined force of this axial support system still precisely balances the gravity component of the mirror along the optical axis. When the mirror surface error is large and does not meet the observation requirements during the observation process, the mirror surface shape needs to be corrected. The electronic control system controls the force actuator 14 to output force to act on the balance weight 12. The force actuator 14 outputs force, which acts on one end of the second force transmission rod 6 through the third force transmission rod 7. The force is amplified and output to the first force transmission rod 4. The combined force direction of the three groups of first force transmission rods 4 evenly distributed around the circumference pushes the force sensor vertically upward or downward, realizing the thrust or pull effect on the mirror surface, and completing the active correction of the mirror surface shape.

[0038] In this embodiment, the output end of the axial support system of an astronomical telescope mirror is connected to the supported mirror through a force sensor, and the other end is fixed to the mirror chamber. The passive force part is in the form of a balancing weight. The gravity exerted on the weight is amplified by a force amplification mechanism to just balance the gravity of the mirror body. During the observation process of the telescope, the passive force can automatically adjust its size as the pointing angle changes, and can always meet the requirement of balancing the axial gravity of the mirror body without human intervention. After the passive force is amplified by the force amplification mechanism, the resultant lateral force is zero, and the output force direction is along the axis, thereby avoiding the actuator from generating lateral force on the mirror surface. The main power part adopts an electromechanical permanent magnet force actuator, and the main force is only used to correct the surface shape of the mirror, so a lower output force stroke range can be selected.

[0039] The force output end of the axial support system is located on the output shaft of the force actuator. This embodiment fully utilizes the fact that when a single, large-aperture astronomical telescope mirror is actively supported in the axial direction, the axial support force is primarily the weight of the mirror itself, while the force for correcting the mirror's surface shape is a relatively small portion. Therefore, the output force of the mirror's axial support system is designed to consist of a passive force component and an active force component. Specifically, a counterweight-type passive force and an electromechanical permanent magnet-type force actuator active force are provided along the output force axis. The passive force component passively balances the force of gravity on the mirror at various pointing angles. The passive force component automatically adapts to changes in the axial support force of the mirror as the telescope's pointing angle changes, mitigating the effects of gravity deformation on the mirror's surface shape. This allows the mirror to maintain a good surface shape even when no active correction force is required. When correction is required, the active force alone performs the correction. The active force is provided by an electromechanical permanent-magnetic actuator, one end of which is connected to a fixed body and the other to a counterweight. This actuator modifies the active force acting on the counterweight. The passive force is superimposed on the active force and amplified by a force-scaling mechanism, enabling the mirror axial support system to achieve a high final output force. A force sensor is positioned at the force output terminal, directly reflecting the actual output force of the active and passive integrated actuator and ensuring output force accuracy. The passive force of the axial support system is generated by a counterweight, significantly reducing actuator power consumption and control system complexity. This passive force is used to balance the axial weight of the mirror itself. As the telescope's pointing angle changes, the axial weight of the mirror changes accordingly. The mirror axial support system can automatically adjust its output force to still precisely balance the axial weight of the mirror. The active force of the axial support system is generated in part by the actuator. The passive force, active force, and their combined force in this axial support system are always coaxial with the actuator's final output force. By varying the magnitude of the active force, the final axial support output force can be adjusted to thrust or tension. The combined force of the counterweight's weight and the electromechanical permanent magnetic force actuator is amplified by a force scaling mechanism, thereby reducing the travel range of the counterweight's own weight and the electromechanical permanent magnetic force actuator. In the event of an unexpected power outage in the control system, the active force is provided by the force actuator, which self-locks to maintain a constant output force, ensuring mirror safety. The connecting rod assembly ensures that the generation of the passive and active forces is always coaxial with the final output force of the mirror axial support system, and reverses the direction of generation of the passive and active forces before outputting them.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For example, the force actuator in Example 2 utilizes an electromechanical permanent magnet force actuator to apply the primary force. However, if other force actuators, such as electromechanical or piezoelectric, were used to apply the primary force, they would also fall within the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. An axial support system for an astronomical telescope mirror, characterized in that: The invention comprises a force sensor, a flexible member, a connecting rod assembly, a fixed structure, and a counterweight. The output force end of the force sensor is arranged on the output force axis of the axial support system and is connected to the mirror surface. The connecting rod assembly comprises a first force transmission rod, a second force transmission rod and a third force transmission rod. The first force transmission rod and the second force transmission rod are hinged through a first hinge point, and the second force transmission rod and the third force transmission rod are hinged through a second hinge point. The force sensor is hinged to the first force transmission rod through the flexible member, and the third force transmission rod is hinged to the counterweight through a third hinge point. The third hinge point is far away from the mirror chamber relative to the second hinge point, so that the third force transmission rod is hinged to the second hinge point. The angle of the force transmission rod is less than 90°, so that the gravity of the counterweight can be amplified and output in the reverse direction as the source power of passive support. The rod body of the second force transmission rod between the first hinge point and the second hinge point is hinged to the fixed structure through the fourth hinge point. The fixed structure is fixed to the mirror chamber. The counterweight is arranged along the output force axis and is located in the internal space formed by the upper fixed structure, the lower mirror chamber, and the circumferential multiple connecting rod assemblies. The circumferential multiple connecting rod assemblies amplify the source power while ensuring that the source power is coaxial with the final output force. The counterweight is installed on the mirror chamber through a vertical guide mechanism.

2. The axial support system for an astronomical telescope mirror according to claim 1, characterized in that: It also includes a force actuator, which is vertically fixed on the fixed structure. The output end of the force actuator faces the balance weight and is connected to the balance weight.

3. The axial support system for an astronomical telescope mirror according to claim 1, characterized in that: The length of the second force transmission rod between the first hinge point and the fourth hinge point is smaller than the length of the second force transmission rod between the second hinge point and the fourth hinge point.

4. The axial support system for an astronomical telescope mirror according to claim 1, characterized in that: A base is fixedly mounted on the mirror chamber, and the fixed structural member and the vertical guide mechanism are both fixedly mounted on the base.

5. The axial support system for an astronomical telescope mirror according to claim 4, characterized in that: The fixed structure is connected to the base through a plurality of vertical connecting rods.

6. The axial support system for an astronomical telescope mirror according to claim 1, characterized in that: The vertical guide mechanism includes a linear bearing sleeve and a guide shaft. A groove is provided at the bottom of the balancing weight, and the linear bearing sleeve is installed in the groove. One end of the guide shaft is fixed and the other end is sleeved in the linear bearing sleeve. The balancing weight can slide freely on the guide shaft using the linear bearing sleeve.

7. The axial support system for an astronomical telescope mirror according to claim 1, characterized in that: The output force end of the force sensor is connected to the mirror surface via an Invar pad.

8. The axial support system for an astronomical telescope mirror according to claim 1, characterized in that: Several sets of the axial support systems act together on the mirror surface to balance the gravity of the mirror body.

9. The axial support system for an astronomical telescope mirror according to claim 1, characterized in that: When the telescope points toward the zenith, the counterweight slides downward along the vertical guide mechanism under the action of its own gravity. The gravity acts on one end of the second force transmission rod through the third force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The combined force of the circumferentially arranged first force transmission rods pushes the force sensor vertically upward, thereby exerting a vertical upward supporting force on the mirror surface. When the telescope points at an angle to the zenith, the balance weight tends to slide downward along the guide mechanism. At this time, the gravity of the balance weight along the guide axis is converted into an axial force along the third force transmission rod, acting on one end of the second force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes the force sensor axially, thereby providing an upward supporting force perpendicular to the bottom of the mirror. The final resultant force is exactly balanced with the gravity component of the mirror body along the optical axis.

10. The axial support system for an astronomical telescope mirror according to claim 2, characterized in that: When the telescope points to the zenith, the balance weight tends to slide downward along the vertical guide mechanism under the action of its own gravity, and the gravity acts on one end of the second force transmission rod through the third force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes the force sensor in the vertical upward direction, thereby providing a vertical upward supporting force on the mirror surface; when the telescope points to an angle with the zenith, the balance weight tends to slide downward along the guide mechanism. At this time, the gravity of the balance weight along the guide axis is converted into an axial force along the third force transmission rod, acting on one end of the second force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes the force sensor in the axial direction, thereby providing an upward supporting force perpendicular to the bottom of the mirror surface, and the final resultant force is exactly balanced with the gravity component of the mirror body along the optical axis; Realize the passive supporting force of the axial support system on the mirror surface; When the mirror surface shape error is large and does not meet the observation requirements during the observation process, the control force actuator outputs force to the balance weight, which acts on one end of the second force transmission rod through the third force transmission rod, and is transmitted from the other end of the second force transmission rod to the first force transmission rod. The resultant force of the circumferentially arranged first force transmission rods pushes or pulls the power sensor downward in the vertical upward direction, thereby realizing active correction of the mirror surface shape.

Images