Axial supporting system of astronomical telescope mirror surface

Abstract

The invention discloses an axial supporting system of an astronomical telescope mirror surface, which comprises a force sensor, a flexible part, a connecting rod assembly, a fixed structural part and a balancing weight, and can also comprise a force actuator. When the mirror surface is passively supported, passive supporting of the mirror surface is not limited by the number of supports and the positions of the supports, the additional lateral force effect on the mirror surface is avoided, large-proportion force scaling can be achieved, and the shape and the gravity center position of the balance weight do not affect the magnification times of output force. When active and passive integrated supporting of the mirror surface is achieved, a driven power part does not need to be controlled by a control system, a force actuator for correcting the surface shape of the mirror surface only needs to provide a stroke range required by correction force, supporting force of a gravity part of the mirror surface does not need to be overlapped, and the correction precision is high. The passive force generated by the counterweight, the active force of the force actuator and the final output force of the mirror surface axial support system are coaxial, so that the axial support system can be prevented from accidentally generating the radial force effect on the mirror body, and the precision of the correction force required for correcting the surface shape of the mirror surface is ensured.

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 axial support of a large-aperture thin mirror when there is a main driving force part. Background Art

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

[0003] Passive support is mainly used in situations where the mirror diameter-to-thickness ratio is relatively small. For primary mirrors with an aperture of less than 2.5 meters, the axial support of mirrors with a diameter-to-thickness ratio of less than 10 usually adopts passive support. The function of the mirror passive support is to support the mirror so that the mirror surface error after support meets the design requirements of the telescope optical system. Usually, the root mean square error of the mirror surface should at least meet the requirement of one-thirtieth of the wavelength, or even higher. In order to maintain the mirror surface shape after processing, higher requirements are placed on the mirror passive support system. At present, there are two main forms of passive support systems used for astronomical telescope mirror support: Whiffle-tree support and passive counterweight support. Whiffle-tree support is widely used in passive support of small-diameter mirrors. Through the automatic adjustment of the lever in the Whiffle-tree support structure, the axial support of the mirror can be well completed. The design of the Whiffle-tree support is closely related to the number of support points. As the number of support points increases, the number of layers of the Whiffle-tree support structure increases and the structure becomes more complex. Therefore, the Whiffle-tree structure is generally not used for large-diameter mirror support. For some mirrors with small diameters but lightweight mirrors behind them, it is not convenient to use the Whiffle-tree structure for support. Another type of counterweight passive support can meet the requirements of multi-support point support. Even for lightweight mirrors, the positions of each support point can be arranged more conveniently to support the mirror. However, the working principle of the conventional counterweight passive support is to use the gravity of the counterweight to be amplified by the lever. This lever form is similar to the structure of a seesaw. Its disadvantage is that the gravity of the counterweight is easily amplified by the lever to generate lateral force on the mirror when supporting the mirror. Thereby affecting the mirror support effect and deteriorating the mirror surface quality.

[0004] Active optical technology mainly corrects the mirror surface errors caused by manufacturing, installation, gravity field, and temperature gradient of telescope mirrors. In the past three decades, active optical technology has been widely used in ground-based telescopes. Active optical mirror support system is one of the key technologies 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 itself has a small mass. After adopting multi-point active support, the output force range for each support point is generally in the order of -200N~+200N. Therefore, the force actuators usually used are only active. There are four main forms of active force actuators: electromechanical, hydraulic, pneumatic and piezoelectric force actuators. When the output force of the force actuator required to be provided is more than 1000N, the design size of the electromechanical force actuator needs to be significantly increased, and the oil or air supply pressure needs to be increased for the hydraulic and pneumatic force actuators. A larger output force can also be achieved by increasing the cross-sectional area of ​​the oil cylinder or cylinder. If the cross-sectional area of ​​the oil cylinder or air cylinder is increased, the size of the actuator will also increase. If the oil pressure or air pressure is increased, oil or air leakage is likely to occur. In addition, both hydraulic and pneumatic actuators have the problem that the output force of the force actuator is zero when the power is off. Although piezoelectric force actuators have the advantages of high precision and high frequency, they are difficult to overcome the disadvantages of low stroke and no output force when the power is off. When only active force actuators are used to support the mirror, the active force should include the mirror's own weight and the correction force required to correct the mirror's surface shape. Therefore, for the axial support of a single large-diameter lens, it is not suitable to use only active force actuators. The main part of the axial support force of a single large-diameter 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 surface shape is about one-third or less of the entire output force. Therefore, in order to reduce the design difficulty of the force actuator, the passive support force part is usually separated from the active correction force, that is, the passive support force is used to balance the gravity required along the optical axis direction of the telescope at different pointing angles. The active correction force is used to adjust the mirror surface error of the telescope at different pointing angles. For example, the 8-meter primary mirror support of the Very Large Telescope (VLT) of the European Southern Observatory adopts a combination of hydraulic passive support and electromechanical force actuator to realize the design of passive plus active force actuator. In the actual working process, as the pointing angle of the telescope changes, the hydraulic pressure of the balanced gravity part required for the axial support of the mirror also changes accordingly, so the pressure of the hydraulic system that provides the passive force must also be controlled manually. The active correction force required for the correction of the mirror surface error must also be adjusted through the control system. Therefore, the passive plus active support force actuator actually requires two sets of control systems, one for controlling the oil pressure and one for the active correction control of the mirror surface adjustment. The complexity of the control system is increased, and the hydraulic part needs to always maintain the power supply state to provide oil pressure.Another passive plus active solution only uses a counterweight support, in which the counterweight part consists of two parts, one of which is fixed and used to balance the gravity of the mirror, and the other part is adjusted by the motor screw to change the power arm of the lever part, so as to achieve the change of the actuator output force to correct the mirror surface error. For example, the New Technology Telescope (NTT) telescope of the European Southern Observatory has the disadvantage that the output force adopts the form of a lever, which is easy to generate radial lateral force while generating axial force, thus affecting the difficulty of active correction of the surface shape. Summary of the invention

[0005] In view of the above 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. The 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 the passive counterweight support form is still adopted, the arrangement form of the lever is changed to achieve that the final output force of the passive support only has an axial force perpendicular to the bottom surface of the mirror surface. The 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 influence of the heating of the actuator on the seeing degree 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, comprising a force sensor, a flexible member, a connecting rod assembly, a fixed structural member, and a counterweight, wherein 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, 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, the third force transmission rod and the counterweight are hinged 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 used as the source power of passive support after being amplified and output in the reverse direction. 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.

[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 counterweight and is connected to the counterweight.

[0009] Further, 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 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 that 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 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 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 to the first force transmission rod from the other end of the second force transmission rod. The combined 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 direction; the passive supporting force of the axial support system on the mirror is realized; 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, and 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 shape 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 for the mirror, it will not be affected by the diameter of the mirror. When the diameter of the mirror is large, it is still convenient to arrange various passive supports. At the same time, even after the back of the mirror is lightweighted, it is very convenient to use the system of the present invention for support. Four beneficial effects are achieved: First, the design of passive support for the mirror is no longer limited by the number of supports and the position of supports; second, when passive support for the mirror is realized, no additional lateral force will act on the mirror; third, three groups of circumferentially evenly distributed force transmission rod force scaling mechanisms can achieve a larger 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 shape correction force. The axial force used to balance 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 used to correct 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 working principle diagram of the first embodiment when the telescope is pointed to the zenith;

[0021] Figure 2 is a working principle diagram of the first embodiment when the telescope points to other pointing angles;

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

[0023] Figure 4 It is a working principle diagram 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 further described in detail below in conjunction with the accompanying drawings.

[0026] Embodiment 1

[0027] The axial support system for the mirror of an astronomical telescope in 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 the mirror of an astronomical telescope in this embodiment mainly includes a force sensor 2, a flexible member (in this embodiment, a flexible rod 3 is preferably used to facilitate the transmission of axial force), a connecting rod assembly, a fixed structure 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 which 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, and 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, and the other end of the force sensor 2 is hinged to the first force transmission rod 4 through a 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°. The rod body of the second force transmission rod 6 between the first hinge point and the second hinge point is hinged to the fixed structure 5 through the fourth hinge point. In order to achieve the force amplification effect, in this embodiment, the length of the second force transmission rod 6 between the first hinge point and the fourth hinge point is preferably set to be less than the length of the second force transmission rod 6 between the second hinge point and the fourth hinge point. The fixed structure 5 is fixed to the mirror chamber 15. The balance weight 12 is located in the internal space formed by the upper fixed structure 5, the lower mirror chamber 15, and the circumferential multiple connecting rod assemblies (in this embodiment, 3 groups of connecting rod assemblies are preferably evenly distributed in the circumferential direction). The balance weight 12 is installed on the mirror chamber 15 through a vertical guide mechanism. The connecting rod assembly can effectively convert the gravity of the balance weight hammer along the axial component of the mirror surface into the axial support force of the axial support system on the mirror surface. The circumferential multiple connecting rod assemblies can ensure that the source power is coaxial with the final output force but in the opposite direction while amplifying the source power. In this embodiment, the base 9 is preferably fixedly installed on the mirror chamber 15, and the base 9 serves as the installation basis of the fixed structure 5, the vertical guide mechanism, etc. In this embodiment, the vertical guide mechanism preferably includes a linear bearing sleeve 11 and a guide shaft 10. A groove is provided at the bottom of the counterweight 12, 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 by using the linear bearing sleeve 11. In this embodiment, the fixed structure 5 is connected to the base 9 by a plurality of (preferably 3) fixed structure connecting rods 8.

[0029] like Figure 1As shown, when the telescope points to the zenith, under the action of downward gravity, the counterweight 12 tends to slide downward, and the gravity 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 direction of the three groups of first force transmission rods 4 evenly distributed in the circumferential direction pushes the force sensor vertically upward, thereby realizing the vertical upward support force on the mirror surface. In actual application, several sets of the above-mentioned axial support systems work together to automatically adjust the size of the passive force in each pointing angle direction of the telescope to just completely balance the gravity of the mirror body at all times without human intervention.

[0030] like Figure 2 As shown, when the telescope is pointing at an angle to the zenith, under the action of gravity, the counterweight 12 tends to slide downward along the guide shaft 10, and the gravity of the counterweight 12 is converted into the component force along the guide shaft 10 to act on the axial force of the third force transmission rod 7 to act on one end of the second force transmission rod 6, and 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, and the final resultant force is still just balanced with the gravity component force of the mirror body along the optical axis.

[0031] In this embodiment, one 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 force output end of the axial support system is arranged on the output shaft of the passive support system, and a counterweight is arranged along the direction of the output force axis. The counterweight is subjected to gravity to generate the source power of the passive support, and the source power is amplified by the connecting rod assembly evenly distributed in the circumference to achieve a larger output force (driven force). The force sensor is arranged at the end of the force output to directly reflect the actual output force of the passive support, thereby ensuring the accuracy of the output force. The axial support system uses the gravity of the counterweight hammer to be amplified by the force scaling mechanism to balance the gravity of the mirror body. During the observation of the telescope, as the pointing angle changes, the axial support system can automatically adjust the output passive force to always meet the requirements of balancing the axial gravity of the mirror body. The direction of the resultant force output by the passive force is only the axial direction perpendicular to the bottom surface of the mirror body, thereby avoiding the actuator from generating a lateral force 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 gravity of the mirror body along the axial direction. When the pointing angle of the telescope changes, the gravity of the mirror body along the axial direction changes accordingly. At this time, the axial support system can automatically change and still just balance the gravity of the mirror body along the axial direction, that is, the counterweight is automatically adjusted as the pointing angle of the telescope changes, and the requirement of balancing the gravity of the mirror body can always be achieved; 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 uniformly distributed force transmission rod force scaling mechanism, so a larger final output force can be achieved while providing a smaller counterweight, and it is ensured that the final output force is only an axial force perpendicular to the mirror surface; the circumferentially uniformly 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 of the counterweight of the axial support system and the position of the center of gravity 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] Embodiment 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 single-chip large-aperture active optical technology mirror support system for an astronomical telescope. The system provides axial support for a large-aperture thin mirror or a lightweight mirror when the overall weight of the mirror is still relatively large. At the same time, the active power part in 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 the first embodiment, except that a force actuator 14 (preferably an electromechanical permanent magnet force actuator) is added on the basis of the first embodiment, and the force actuator 14 is fixed to the fixed structure 5 by screws, and the output end of the force actuator 14 is connected to the counterweight 12. The system converts the downward gravity of the counterweight hammer into an axial support force of the upward counterweight of the mirror body, and decomposes the axial support force required for the mirror surface into a passive force and an active force part. The passive force part is in the form of a counterweight hammer, which is used to balance the gravity of the mirror body itself. The passive force part can automatically adjust the size of the passive force in all pointing angles of the telescope to completely balance the gravity of the mirror body without human intervention. When the passive force is output, it is only along the axial direction, and its lateral resultant force is zero, thereby avoiding the actuator from generating a lateral force on the mirror surface. The main force part is used to correct the mirror surface shape. Since the main force is only used to correct the mirror surface shape and there is a connecting rod assembly, a lower output force stroke range can be selected. The process of applying the main force by the force actuator will not change the size of the passive force. Therefore, the applied main force is only used to correct the mirror surface shape error. The main force and passive force of the system are finally converted into a supporting force along the axis. The passive force, main force and the 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 main force and then output. The main power part in this embodiment preferably uses an electromechanical permanent magnet force actuator.

[0036] like Figure 3 As shown, when the telescope points to the zenith, under the downward gravity, the counterweight 12 tends to slide downward, and the gravity 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 direction of the three groups of evenly distributed third force transmission rods 4 in the circumferential direction pushes the force sensor vertically upward, thereby realizing the vertical upward passive support force on the mirror surface. In actual application, nearly a hundred sets or more of this axial support system work together to just balance the gravity of the mirror body. When the mirror surface error is large and does not meet the observation requirements and needs to be corrected during the observation process, the force actuator 14 is controlled by the electronic control system 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 evenly distributed first force transmission rods 4 in the circumferential direction pushes the force sensor vertically upward or pulls it downward, 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 points at an angle to the zenith, under the action of gravity, the counterweight 12 tends to slide downward along the guide shaft 10, and the gravity of the counterweight 12 is converted into the component force along the guide shaft 10 to act on one end of the second force transmission rod 6. The force is amplified by the lever principle and then 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 support force perpendicular to the bottom of the mirror. The final resultant force of all the axial support systems is still just balanced with the gravity component force of the mirror body 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 force actuator 14 is controlled by the electronic control system 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 evenly distributed first force transmission rods 4 in the circumferential direction pushes the force sensor vertically upward or pulls it downward, thereby realizing the thrust or pull effect on the mirror surface and completing the active correction of the mirror surface shape.

[0038] In the present 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, and the gravity exerted on the weight is amplified by a force amplification mechanism to balance the gravity of the mirror body. During the observation of the telescope, the passive force can be automatically adjusted as the pointing angle changes, and the requirement of balancing the axial gravity of the mirror body can always be met 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 preventing the actuator from generating lateral force on the mirror. The main power part adopts an electromechanical permanent magnet force actuator, and the main force is only used to correct the mirror surface shape, so a lower output force travel range can be selected.

[0039] The force output end of the axial support system is arranged on the output shaft of the force actuator. This embodiment makes full use of the fact that when the monolithic large-aperture mirror of the astronomical telescope adopts axial active support, its axial support force is mainly the gravity of the mirror body itself, while the correction force for the mirror surface shape is a relatively small part, so it is proposed to design the output force of the mirror axial support system to be a superposition of the passive force part and the active force part, that is, a counterweight passive force and an electromechanical permanent magnet force actuator active force are provided along the axis direction of the output force. The passive force part is used to passively balance the gravity of the mirror in each pointing angle direction. The passive force part can automatically adapt to the change of the axial support force of the mirror body when the pointing angle of the telescope changes, thereby improving the influence of gravity deformation on the mirror surface shape. When there is no need to provide active correction force, the mirror surface shape can still be maintained in a good state. When the mirror surface shape needs to be corrected, the mirror surface shape is corrected only by the active force. The main force is provided by an electromechanical permanent magnet force actuator. One end of the electromechanical permanent magnet force actuator is connected to a fixed body, and the other end is connected to a counterweight. The main force acting on the counterweight is changed. The passive force and the main force are superimposed and amplified by a force scaling mechanism, so that the mirror axial support system can achieve a larger final output force. The force sensor is arranged at the end of the force output, which directly reflects the actual output force of the active and passive integrated force actuator to ensure the accuracy of the output force. The passive force of the axial support system is generated by a counterweight hammer, which significantly reduces the power consumption of the force actuator and the complexity of the control system. This passive force is used to balance the gravity of the mirror body along the axial direction. When the pointing angle of the telescope changes, the gravity of the mirror body along the axial direction changes accordingly. At this time, the mirror axial support system can automatically adjust the output force to still just balance the gravity of the mirror body along the axial direction; the main force of the axial support system is generated by the force actuator. The passive force, active force and their combined force of the axial support system are always coaxial with the final output force of the actuator. By changing the size of the active force, the final output force of the axial support can be achieved as a thrust or a pull. The combined force of the weight of the counterweight and the electromechanical permanent magnetic force actuator are amplified by the force scaling mechanism, thereby reducing the weight of the counterweight and the travel range of the electromechanical permanent magnetic force actuator. When the control system loses power unexpectedly, its active force is provided by the force actuator, which can self-lock when the power is off, so that the output force remains unchanged, ensuring the safety of the mirror. The connecting rod assembly realizes the generation of the passive force and the active force, which are always coaxial with the final output force of the mirror axial support system, and the generation direction of the passive force and the active force is reversed before output.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For example, the force actuator in the second embodiment is applied by an electromechanical permanent magnet force actuator. If other forms of force actuators such as electromechanical, piezoelectric, etc. are used to apply the main force here, they 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 should be included in 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, wherein 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, 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, the third force transmission rod and the counterweight are hinged 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 The angle of the force transmission rod is less than 90°, so that the gravity of the counterweight can be used as the source power of passive support after being amplified and output in the reverse direction. 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, and the output end of the force actuator faces the counterweight and is connected to the counterweight.

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 to the zenith, the counterweight slides 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 combined force direction of the circumferentially arranged first force transmission rods pushes the force sensor vertically upward, thereby exerting a vertically upward supporting force on the mirror surface; When the telescope points at an angle to the zenith, the counterweight tends to slide downward along the guide mechanism. At this time, the gravity of the counterweight 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 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 to the first force transmission rod from the other end of the second 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 that acts on one end of the second force transmission rod, and is transmitted to the first force transmission rod from the other end of the second 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 counterweight, 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 or pulls the power sensor downward in the vertical upward direction, thereby realizing active correction of the mirror surface shape.

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