A secondary mirror position adjustment mechanism for large-aperture and large-field telescopes

Abstract

The present disclosure relates to the technical field of optical instruments, and specifically provides a secondary mirror position adjustment mechanism for a large-aperture, large-field-of-view telescope. The secondary mirror position adjustment mechanism includes a base and a leg, one end of the leg is connected to the upper surface of the base, and the other end is connected to the frame of the telescope; the lower surface of the base is connected to the secondary mirror assembly. The position of the secondary mirror is adjusted by adjusting the length of the leg. There are six legs, including three vertically arranged first legs and three horizontally arranged second legs. The first legs and the second legs act independently on the secondary mirror position adjustment without coupling influence. The secondary mirror position adjustment mechanism provided by the present disclosure has a new configuration, which realizes convenient and effective connection with the frame of the telescope, and meets the installation space requirements of the correction lens group and the detector. The secondary mirror position adjustment mechanism has a simpler solution method, and the design and implementation of the drive control system are also simpler.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical instruments, and in particular to a secondary mirror position adjustment mechanism for a large-aperture, large-field-of-view telescope. Background Art

[0002] Astronomical optical telescopes are essential instruments for observing celestial bodies, and large-field astronomical telescopes are a current hotspot in research and development. Large-aperture, large-field telescopes play a vital role in astronomical observations and space monitoring. First, large-aperture, large-field telescopes are essential for conducting large-scale, multispectral surveys of the sky. By generating timely, high-quality, and high-throughput observational data, and combining multiple wavelengths and methods to conduct in-depth surveys of large areas of the sky, they are crucial for answering fundamental questions in cosmology. Second, large-aperture, large-field telescopes provide astronomers with a wealth of observational information, enabling them to explore the effects of gravitational lensing in galaxy clusters and understand the properties of gravitational wave and X-ray burst sources. Furthermore, asteroid detection requires highly sensitive, fast-scanning, large-aperture, large-field telescopes to conduct continuous and precise observations of near-Earth asteroid threats. Therefore, the construction of a new generation of large-field survey telescopes, providing large-scale digital image survey capabilities and continuously achieving breakthroughs in image sensitivity and temporal resolution, has become a major trend in the development of ground-based optical equipment. Summary of the Invention

[0003] The purpose of this disclosure is to address the technical problems in the related art and provide a secondary mirror position adjustment mechanism for large-aperture and large-field-of-view telescopes. The specific solution is as follows:

[0004] An embodiment of the present application provides a secondary mirror posture adjustment mechanism for a large-aperture, large-field-of-view telescope, characterized in that it is used for adjusting the posture of the secondary mirror and includes: a base, which is a circular flat plate having an upper surface and a lower surface parallel to each other, and the lower surface is connected to the secondary mirror through a secondary mirror chamber; a leg, one end of the leg is connected to the upper surface, and the other end is connected to the frame of the telescope, and is configured to adjust the posture of the secondary mirror, wherein six legs are provided, including three first legs and three second legs, the axial direction of the first leg is perpendicular to the upper surface, and the axial direction of the second leg is parallel to the upper surface; the first leg and the second leg act independently on the secondary mirror posture adjustment without coupling influence.

[0005] In some embodiments, the lengths of the three first legs are adjusted to control the axial translation and tilt in two directions of the secondary mirror; the lengths of the three second legs are adjusted to control the axial rotation and lateral translation in two directions of the secondary mirror.

[0006] In some embodiments, the leg includes: a transmission assembly, which is configured to provide the leg with one degree of freedom of translation along the axis of the leg and one degree of freedom of rotation around the axis of the leg; two flexible hinges, which are respectively arranged at both ends of the transmission assembly, and each flexible hinge is configured to provide the leg with two degrees of rotational freedom.

[0007] In some embodiments, the transmission assembly includes: a motor configured to drive the transmission assembly; and a screw configured to convert the rotational motion of the motor into linear motion, wherein the motor and the screw enable the transmission assembly and the legs to be extended and shortened, and the legs can be adjusted in length under the drive of the motor.

[0008] In some embodiments, in the axial direction of the leg, the difference between the maximum length and the minimum length of the leg that can be adjusted is less than the minimum length of the leg. .

[0009] In some embodiments, both ends of the support leg are respectively connected to the telescope frame and the base, and the base is connected to the secondary mirror through a secondary mirror chamber. Therefore, in response to the movement of the support leg, the secondary mirror changes its position relative to the frame; wherein, the frame includes a central tube, the axis of the central tube coincides with the optical axis of the telescope, and one end of the support leg is linked to the central tube of the frame.

[0010] In some embodiments, the relationship between the change in leg length and the change in secondary mirror posture is:

[0011] ;

[0012] ,

[0013] The Jacobian matrix is and , the length change of the first leg is , the length change of the second leg is , the position change of the secondary mirror is 、 ,in 、 、 Represents translation in three directions, 、 、 Indicates rotation in 3 directions.

[0014] Compared to related technologies, the above-described embodiments of the present disclosure have at least the following advantages: the secondary mirror position adjustment mechanism for a large-aperture, large-field-of-view telescope provided by the present disclosure has a novel configuration, namely, a novel leg arrangement. This novel configuration enables the legs of the position adjustment mechanism to be conveniently and effectively connected to the large-aperture, large-field-of-view telescope, meeting the installation space requirements for the correction lens assembly and detector. Compared to existing hexapod mechanisms, the design and implementation of the drive control system for the secondary mirror position adjustment mechanism of the present disclosure is also simpler.

[0015] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0017] Figure 1 It is a schematic diagram of a secondary mirror posture adjustment mechanism for a large-aperture, large-field-of-view telescope according to an exemplary embodiment.

[0018] Figure 2 is a schematic diagram of a supporting leg according to an exemplary embodiment.

[0019] Figure 3 It is a schematic diagram of the internal structure of a transmission assembly in a support leg according to an exemplary embodiment.

[0020] Figure 4 The present invention is a schematic diagram showing the connection between a secondary mirror posture adjustment mechanism for a large-aperture, large-field-of-view telescope and the four-wing beams and secondary mirror assembly of the telescope according to an exemplary embodiment.

[0021] Figure 5 yes Figure 4 Exploded diagram.

[0022] Figure 6 The figure is a simplified structural diagram of a secondary mirror posture adjustment mechanism for a large-aperture, large-field-of-view telescope according to an exemplary embodiment.

[0023] Reference numerals:

[0024] Secondary mirror position adjustment mechanism 100; base 110, upper surface 112, wedge block 113;

[0025] Support leg 120, first support leg 121, second support leg 122;

[0026] Flexible hinge 1210, transmission assembly 1220, roller screw shaft 1221, roller screw nut 1222, transmission plate 1223, transmission shaft 1224, harmonic reducer 1225, motor 1226, limit switch 1227, bearing 1228, bearing seat 1229, pillar 1230;

[0027] A secondary mirror assembly 130, a secondary mirror 131, and a secondary mirror chamber 132;

[0028] Four wing spars 140, central tube 141, outer ring 142, blades 143;

[0029] Detector assembly 150 . DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present disclosure more clear, the present disclosure will be further described in detail below with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present disclosure, rather than all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present disclosure without creative effort are intended to fall within the scope of protection of the present disclosure.

[0031] The terms used in the embodiments of the present disclosure are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure. The singular forms "a," "the," and "the" used in the embodiments of the present disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "A variety of" generally includes at least two, and other quantifiers are similar.

[0032] It should be understood that although the terms "first," "second," "third," etc. may be used to describe in the present disclosure, these descriptions should not be limited to these terms. These terms are only used to distinguish the objects being described. For example, without departing from the scope of the present disclosure, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. In addition, the terms "first," "second," "third," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0033] It should be understood that the term "and / or" as used herein is merely a description of an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " as used herein generally indicates that the associated objects are in an "or" relationship. The singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0034] It should be further understood that the terms "center", "longitudinal", "lateral", "front", "back", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0035] In the description of this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present disclosure based on the specific circumstances.

[0036] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0037] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0038] A large-aperture, wide-field-of-view telescope typically consists of a primary mirror assembly, a secondary mirror assembly, a tertiary mirror assembly, a correction lens group, a detector, and a frame. The primary mirror is the primary focusing surface of a reflecting telescope. Light is reflected from the primary mirror to the secondary mirror; the secondary mirror is a second mirror that focuses the light. The light then passes through the tertiary mirror, correction lens group, and other components to the detector, resulting in an image. The primary, secondary, tertiary mirror, correction lens group, and detector are all fixed to the frame. To ensure excellent image quality, the primary, secondary, and tertiary mirrors in a telescope must maintain precise relative positions. However, due to structural deformation due to gravity, thermal loads, and wind loads, the frame can deform, causing misalignment of the optical system. This in turn can lead to tilt and decentration of the optical components, resulting in positional errors. The primary mirror is the heaviest component in the optical system and has the most complex support system. Therefore, to maintain relative position among the optical components, the other components must be moved relative to the primary mirror. Therefore, the secondary mirror, tertiary mirror, and correction lens group all require secondary mirror position adjustment mechanisms for active alignment. The Stewart hexapod platform, which is widely used in many industries, can be used for posture adjustment.

[0039] The prime focus structure employed in large-aperture, wide-field telescopes presents certain unique characteristics. The corrective lens assembly and detector must pass through the central aperture of the secondary mirror. Furthermore, the corrective lens assembly, detector, and secondary mirror assembly are all connected to the four wing beams of the telescope frame. This leaves very limited space for the secondary mirror's position adjustment mechanism, particularly in the radial direction. This places strict restrictions on the radial envelope dimensions of the adjustment mechanism: the outer envelope cannot be too large, otherwise it will affect the primary mirror's light-collecting area; the inner envelope cannot be too small, otherwise it will interfere with the corrective lens assembly and detector. Due to the complex structure and limited radial mounting space, the traditional three-V Stewart hexapod platform cannot be used for the secondary mirror assembly's position adjustment. Therefore, a non-traditional secondary mirror position adjustment mechanism is required.

[0040] To ensure the accurate position of the secondary mirror, the adjustment mechanism needs to have precise kinematic accuracy; in addition, since the large-field-of-view prime focus telescope system does not have a fast reflecting mirror, it is subject to strict vibration restrictions, which requires the adjustment mechanism to have higher stiffness to produce a higher natural frequency.

[0041] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a secondary mirror position adjustment mechanism for large-aperture and large-field-of-view telescopes, which meets the installation structure requirements and radial space requirements of the secondary mirror assembly of large-aperture and large-field-of-view telescopes, and at the same time has high positioning accuracy and rigidity, thereby realizing precise adjustment of the secondary mirror position.

[0042] Optional embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0043] The present invention provides a secondary mirror posture adjustment mechanism 100 for a large-aperture and large-field-of-view telescope, which is used for adjusting the secondary mirror posture of a large-aperture and large-field-of-view telescope. Figure 1 As shown, the secondary mirror position adjustment mechanism 100 includes a base 110 and six legs 120. The base 110 has an upper surface 112 and a lower surface facing away from each other, and the lower surface is configured to be connected to the secondary mirror assembly 130 of the telescope. The legs 120 are provided on the upper surface 112.

[0044] In some embodiments, the base 110 is a circular ring structure, the lower surface of the base 110 is used to connect the secondary mirror assembly 130, the upper surface 112 of the base 110 is used to connect the support leg 120, and the upper surface 112 and the lower surface of the base 110 are both perpendicular to the optical axis, and the optical axis refers to the rotational symmetry center of the telescope optical system.

[0045] In some embodiments, the secondary mirror position adjustment mechanism 100 further includes six length-adjustable legs 120, three of which are first legs 121 and the remaining three are second legs 122. The axes of the first legs 121 are perpendicular to the upper surface 112, and the axes of the second legs 122 are parallel to the upper surface 112.

[0046] In some embodiments, the end of the first leg 121 is directly connected to the upper surface 112, so the axis of the first leg 121 is perpendicular to the upper surface 112. A wedge block 113 is provided on the upper surface 112. The wedge block 113 has two mutually perpendicular planes, one of which is directly connected to the upper surface 112, and the other is connected to the end of the second leg 122. In response to the second leg 122 being connected to the wedge block 113, the axis of the second leg 122 is perpendicular to the upper surface 112.

[0047] There is no specific limitation on the connection method between the first leg 121 and the second leg 122 and the base 110 , and the connection method may be bolt connection, electric induction connection, or any other connection method that can achieve a fixed connection between the two.

[0048] In the present disclosure, the secondary mirror position adjustment mechanism 100 of the above configuration occupies a smaller radial space, and therefore can meet the installation structure requirements and radial space requirements of the secondary mirror assembly 130 of a large-aperture and large-field-of-view telescope.

[0049] In some embodiments, as Figure 4As shown, one end of the first leg 121 is directly connected to the upper surface 112 of the base 110, and the other end is connected and fixed to the central tube 141 of the telescope's four-wing beam 140. One end of the second leg 122 is connected to the upper surface 112 of the base 110 via the wedge block 113, and the other end is connected and fixed to the central tube 141 of the telescope's four-wing beam 140. The four-wing beam 140 and the central tube 141 are part of the telescope frame and are fixed. Therefore, by adjusting the length of the first leg 121 and the second leg 122, the spatial position and posture of the base 110 and the secondary mirror assembly 130 can be adjusted, thereby achieving the position and posture adjustment of the secondary mirror 131.

[0050] The difference between the maximum length and the minimum length that the support leg 120 can adjust is called the stroke of the support leg 120. Compared with the axial size of the support leg 120, the stroke of the support leg 120 is very small, which is smaller than the axial size of the support leg 120. Therefore, when the secondary mirror position adjustment mechanism 100 performs secondary mirror position adjustment, the overall configuration of the secondary mirror position adjustment mechanism 100 changes very little.

[0051] In some embodiments, the six legs 120 have the same structure, such as Figure 2 As shown, the support leg 120 is composed of a transmission assembly 1220 and two flexible hinges 1210 .

[0052] In some embodiments, as Figure 2 As shown, the flexible hinge 1210 is provided on both sides of the transmission assembly 1220. The flexible hinge 1210 can bend and deform in two mutually perpendicular directions. Its structural design allows it to have a certain degree of flexibility in both directions within a plane. Therefore, the flexible hinge 1210 can provide the first leg 121 with rotational freedom in two directions.

[0053] like Figure 2 、 Figure 3 As shown, the transmission assembly 1220 can be equivalent to a linear displacement actuator with high axial stiffness, which can adjust and maintain the length of the leg 120. Figure 3 This is a typical design of a transmission assembly 1220, structurally consisting of a roller screw shaft 1221, a roller screw nut 1222, a transmission plate 1223, a transmission shaft 1224, a harmonic reducer 1225, a motor 1226, a limit switch 1227, a bearing 1228, a bearing seat 1229, and a support 1230. The bearing seat 1229 is fixed to the harmonic reducer 1225 via the support 1230, and the outer ring of the bearing 1228 is fixed to the bearing seat 1229. The inner ring of the bearing 1228 is fixed to the transmission plate 1223 and the transmission shaft 1224. The function of the bearing 1228 is to support the roller screw nut 1222.

[0054] In some embodiments, as Figure 3 As shown, transmission assembly 1220 is driven by motor 1226. The rotational motion of motor 1226 is transmitted to roller screw nut 1222 via harmonic reducer 1225, transmission shaft 1224, and transmission plate 1223. Roller screw shaft 1221 and roller screw nut 1222 convert the rotational motion into linear motion, which is output by roller screw shaft 1221 to adjust the length of leg 120. When motor 1226 is locked, the length of transmission assembly 1220 remains unchanged, thereby maintaining the length of leg 120.

[0055] The drive system for motors 1226 consists of power supply, drive, control, and sensing components, enabling control of the six motors 1226. The control system primarily implements trajectory planning, motor drive, sensor acquisition, and position control. The hardware includes a motor drive board, a control board, and a power board. This drive system controls the rotation of the six motors 1226, thereby controlling the position and posture of the secondary mirror 131.

[0056] In some embodiments, transmission assembly 1220 also has a degree of freedom of rotation about its central axis. Specifically, roller screw shaft 1221 serves as the output shaft, and transmission assembly 1220 does not restrict its axial rotation, thus providing a degree of rotational freedom. Transmission assembly 1220 is secured at both ends to central cylinder 141 and base 110, respectively, via flexible hinges 1210. Therefore, the degree of freedom of rotation of transmission assembly 1220 about its central axis is limited and controllable.

[0057] The secondary mirror position adjustment mechanism 100 provided by the present invention is applied to large aperture and large field of view telescopes, such as Figure 4 、 Figure 5 As shown, the large-aperture, large-field-of-view telescope includes: a secondary mirror assembly 130 , four-wing beams 140 and a secondary mirror position adjustment mechanism 100 , and the secondary mirror position adjustment mechanism 100 is connected to the secondary mirror assembly 130 and the four-wing beams 140 .

[0058] In some embodiments, as Figure 4 The four-wing spar 140 includes an outer ring 142, the diameter of which is greater than the diameter of the secondary mirror assembly 130. The four-wing spar 140 also includes a central tube 141, the axis of which coincides with the optical axis. The four-wing spar 140 also includes blades 143, a plurality of which are provided, with the ends of the blades 143 connected to the central tube 141 and the outer ring 142, respectively. That is, the central tube 141 is fixedly connected to the outer ring 142 via the blades 143, and the outer ring 142 is further fixed to the primary mirror assembly via a lens barrel, a cross-hole, and other structures.

[0059] In some embodiments, the secondary mirror assembly 130 includes a secondary mirror 131 and a secondary mirror chamber 132. The secondary mirror chamber 132 is fixedly connected to the secondary mirror posture adjustment mechanism 100, and the secondary mirror chamber 132 provides stable support and protection for the secondary mirror 131 to ensure that the secondary mirror 131 can function normally.

[0060] In some embodiments, the four-wing beam 140 is a common structure in modern ground-based large-aperture telescopes. Located at the front end of the telescope barrel, it is typically used only to secure the secondary mirror assembly 130. Compared to the four-wing beams used in related art, in large-aperture, large-field-of-view telescopes, the four-wing beam 140 also secures the corrective lens group and detector assembly 150, resulting in a larger central barrel 141 and a more complex structure. The secondary mirror position adjustment mechanism 100 disclosed herein can meet the mounting structural and radial space requirements for the secondary mirror assembly 130 in large-aperture, large-field-of-view telescopes, providing space to accommodate the corrective lens group and detector assembly 150.

[0061] In some embodiments, since the secondary mirror assembly 130, the correction lens group, and the detector all need to be connected to the central tube 141 of the four-wing beam 140, the radial size of the secondary mirror position adjustment mechanism 100 should be limited in large-aperture and large-field-of-view telescopes. The radial envelope size of the secondary mirror position adjustment mechanism 100 should be less than or equal to 1.2 times the radial envelope size of the secondary mirror assembly 130.

[0062] In some embodiments, in order to facilitate the explanation of the principle of the secondary mirror posture adjustment mechanism 100, a space rectangular coordinate system is set, such as Figure 1 and Figure 6 As shown, the center of the coordinate system is located at the geometric center of the upper surface 112 of the base, the z-axis is perpendicular to the upper surface 112 and points upward, the x-axis and the y-axis are coplanar with the upper surface 112, and the directions of the x, y, and z axes conform to the right-hand rule of the spatial rectangular coordinate system.

[0063] In some embodiments, the principle of posture adjustment is explained through kinematic analysis, such as Figure 6 As shown, one end of the leg 120 is connected to the base 110, and the connection point is The other end of the leg 120 is connected to the center tube 141 of the four-wing beam, and the connection point is The position of the central tube 141 is fixed, so the connection point The position of remains unchanged, set the connection point The spatial coordinates of .

[0064] Since the length of the legs 120 changes during the posture adjustment process, the connection point The position of the connection point changes. The position before the change is , the position after the change is According to the geometric relationship, , where t is the position adjustment amount of the secondary mirror assembly 130 and the base 110; R is the rotation matrix calculated according to the posture adjustment amount of the secondary mirror assembly 130 and the base 110.

[0065] Connect the points Changed position and connection point By subtracting the position of the support leg 120, we can get the vector representing the length and direction of the support leg 120 ,Right now Equation It shows the relationship between the position and attitude adjustment amount of the secondary mirror assembly 130 and the base 110 and the length of the support leg 120, indicating that the attitude adjustment of the secondary mirror 131 can be achieved by adjusting the length of the support leg 120.

[0066] Regarding the degrees of freedom of the mechanism, according to the Gruebler equation for calculating the degrees of freedom of the mechanism: When the length of the legs 120 of the secondary mirror posture adjustment mechanism 100 of the large-aperture and large-field-of-view telescope remains unchanged, The secondary mirror posture adjustment mechanism 100 can just completely limit the six degrees of freedom of the secondary mirror 131, so that the relative posture of the secondary mirror 131 and the primary mirror remains unchanged; when the length of the support leg 120 is changed by controlling the rotation of the motor 1226, , the number of degrees of freedom is exactly equal to the number of legs 120, indicating that the secondary mirror position adjustment mechanism 100 can adjust the position of the secondary mirror 131. The secondary mirror 131 has 6 degrees of freedom in space, and the first leg 121 and the second leg 122 independently control the three spatial degrees of freedom of the secondary mirror. Since the axial direction of the first leg 121 is perpendicular to the upper surface, the axial direction of the second leg 122 is parallel to the upper surface 112, and the stroke of the leg 120 is much smaller than the axial dimension of the leg, the translation of the secondary mirror 131 along the z-axis and the rotation around the x-axis and y-axis can be independently controlled by controlling the length of the three first legs 121; and the translation of the secondary mirror 131 along the x-axis and y-axis and the rotation around the z-axis can be independently controlled by controlling the length of the three second legs 122. The secondary mirror 131 has 6 degrees of freedom in space, 3 of which are controlled by the first leg 121 and the other 3 are controlled by the second leg 122, that is, the first leg 121 and the second leg 122 act independently in adjusting the position of the secondary mirror and do not affect each other.

[0067] Therefore, in terms of posture calculation, compared with the existing hexapod mechanisms such as the Stewart platform, the secondary mirror posture adjustment mechanism 100 of the present invention has a simpler posture calculation method, and the first leg and the second leg are independent of each other in the control of the secondary mirror posture and are not coupled.

[0068] In order to compare the secondary mirror posture adjustment mechanism 100 of the present invention with the existing Stewart platform, the calculation methods are briefly introduced. Without loss of generality, the diameters of the bases of the two mechanisms are assumed to be The length of the legs is 600mm. The widely used solution method for the Stewart platform is to establish a mathematical model of the Stewart platform and calculate the Jacobian matrix based on the configuration parameters. :

[0069]

[0070] Leg length change and the base posture change The relationship is: ,in , ,in is the displacement, It's a corner.

[0071] The calculation method of the secondary mirror posture adjustment mechanism 100 of the present invention is as follows: Figure 6 A mathematical model of the posture adjustment mechanism is established, and the Jacobian matrix is ​​calculated according to the configuration parameters:

[0072] ,

[0073] The relationship between the change in leg length and the change in base posture is: , ,in , , , .

[0074] Comparing the above two solution methods, the Jacobian matrix of the Stewart platform is a 6×6 matrix, and the Jacobian matrix of the secondary mirror position adjustment mechanism 100 of the present invention is and Both are 3×3 matrices. The present invention reduces the number of elements in the Jacobian matrix from 36 to 18, thereby improving the calculation efficiency of the Jacobian matrix and simplifying the solution method.

[0075] The benefits of the present invention are further illustrated below by two examples:

[0076] (1) When the base needs to be moved 1 mm in the x direction, according to the above solution method, the adjustment amount of the Stewart platform legs is The adjustment amount of the legs 120 of the secondary mirror posture adjustment mechanism 100 of the present invention is , , only the second leg 122 needs to be adjusted.

[0077] (2) For example, when the base rotates 0.1° around the x-axis, the adjustment amount of the Stewart platform's legs 120° is The adjustment amount of the legs 120 of the secondary mirror posture adjustment mechanism 100 of the present invention is , , only the first leg 121 needs to be adjusted.

[0078] Compared to existing hexapods such as the Stewart platform, the secondary mirror position adjustment mechanism 100 of the present invention has a simpler position calculation method. When adjusting the secondary mirror 131 for translation in any direction, only the adjustment amount of three legs 120 needs to be calculated; the other three legs 120 do not need to be calculated or adjusted. When adjusting the secondary mirror for rotation in any direction, only the adjustment amount of three legs 120 needs to be calculated; the other legs 120 do not need to be calculated or adjusted. Compared with existing hexapods such as the Stewart platform, the secondary mirror position adjustment mechanism 100 of the present invention has significant advantages in terms of calculation method and drive control system design.

[0079] Compared with the related art, the above solution of the embodiment of the present disclosure has at least the following beneficial effects:

[0080] Compared to existing hexapod mechanisms such as the Stewart platform, the secondary mirror position adjustment mechanism 100 for a large-aperture, large-field-of-view telescope provided in the present disclosure has a novel configuration, namely, a novel arrangement of legs 120. This novel configuration allows the legs 120 of the position adjustment mechanism 100 to be conveniently and effectively connected to the central tube 141 of the four-wing beam 140 of the large-aperture, large-field-of-view telescope, enabling the position adjustment mechanism to meet the installation space requirements of the correction mirror assembly and detector.

[0081] The secondary mirror position adjustment mechanism 100 of the present invention offers a simpler position calculation method. The secondary mirror 131 has six degrees of freedom in space. The first leg 121 and the second leg 122 independently control three of the secondary mirror's spatial degrees of freedom. The first leg and the second leg are uncoupled during secondary mirror position adjustment. Therefore, only two 3x3 Jacobian matrices are required to establish the mathematical model of the secondary mirror position adjustment mechanism. This reduces the number of elements in the Jacobian matrices from 36 to 18, simplifying the calculation method and improving computational efficiency.

[0082] Because the calculation of the secondary mirror position adjustment mechanism 100 of the present invention is simpler, the drive control of the mechanism of the present invention is also simpler. When adjusting the secondary mirror 131 to translate in any direction, only the adjustment amount of three of the six legs 120 needs to be calculated, and the other three legs 120 do not need to be calculated or adjusted. When adjusting the secondary mirror 131 to rotate in any direction, only the adjustment amount of three legs 120 needs to be calculated, and the other legs 120 do not need to be calculated or adjusted. Therefore, compared with existing hexapod mechanisms such as Stewart platforms, the design and implementation of the drive control system of the secondary mirror position adjustment mechanism 100 of the present invention is also simpler.

[0083] The specific structure, working principle and beneficial effects of the secondary mirror position adjustment mechanism provided in the embodiments of the present disclosure can refer to the secondary mirror position adjustment mechanism described in any of the above embodiments, and will not be repeated here.

[0084] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. References to the common and similar parts between the various embodiments will be sufficient. For the systems or devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, their descriptions are relatively simple; for relevant details, refer to the descriptions of the methods.

[0085] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present disclosure.

Claims

1. A secondary mirror position adjustment mechanism for a large-aperture, large-field-of-view telescope, characterized in that: Used for posture adjustment of the secondary mirror, including: A base, the base being a circular flat plate having an upper surface and a lower surface parallel to each other, the lower surface being connected to the secondary mirror via a secondary mirror chamber; A support leg, one end of which is connected to the upper surface and the other end of which is connected to the frame of the telescope, and is configured to adjust the position of the secondary mirror, There are six legs, including three first legs and three second legs, the axes of the first legs are perpendicular to the upper surface, and the axes of the second legs are parallel to the upper surface; the first legs and the second legs act independently on the posture adjustment of the secondary mirror without coupling influence; The legs include: A transmission assembly configured to provide the support leg with a degree of freedom of translation along the support leg axis and a degree of freedom of rotation about the support leg axis; Two flexible hinges are respectively arranged at two ends of the transmission assembly, and each flexible hinge is configured to provide two rotational degrees of freedom for the support leg.

2. The secondary mirror position adjustment mechanism according to claim 1, characterized in that: Adjust the lengths of the three first legs to control the axial translation and tilt in two directions of the secondary mirror; adjust the lengths of the three second legs to control the axial rotation and lateral translation in two directions of the secondary mirror.

3. The secondary mirror position adjustment mechanism according to claim 1, characterized in that: The transmission assembly comprises: a motor configured to drive the transmission assembly; a lead screw configured to convert the rotational motion of the motor into linear motion, The motor and the lead screw enable the transmission assembly and the legs to be extended and shortened, and the legs are driven by the motor to adjust their length.

4. The secondary mirror position adjustment mechanism according to claim 3, characterized in that: In the axial direction of the leg, the difference between the maximum length and the minimum length of the leg that can be adjusted is less than the minimum length of the leg. .

5. The secondary mirror position adjustment mechanism according to claim 1, characterized in that: The two ends of the support leg are connected to the telescope frame and the base respectively. The base is connected to the secondary mirror through the secondary mirror chamber. Therefore, in response to the movement of the support leg, the position of the secondary mirror relative to the frame changes. The frame includes a central tube, the axis of the central tube coincides with the optical axis of the telescope, and one end of the support leg is connected to the central tube of the frame.

6. The secondary mirror position adjustment mechanism according to any one of claims 1 to 5, characterized in that: The relationship between the change in the length of the legs and the change in the posture of the secondary mirror is: ； ， The Jacobian matrix is and , the length change of the first leg is , the length change of the second leg is , the position change of the secondary mirror is 、 ,in 、 、 Represents translation in three directions, 、 、 Indicates rotation in three directions, ∆l1, ∆l3, and ∆l5 represent the length changes of the three first legs; ∆l2, ∆l4, and ∆l6 represent the length changes of the three second legs.

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