A FAST feed cabin positioning mechanism

Abstract

The present invention discloses a FAST feed cabin positioning mechanism, including a star-shaped frame, a plurality of sets of flexible cable dual-drive mechanisms and a feed platform, etc. The feed platform includes a lower platform and a lower platform adapter ring, and a multi-beam feed receiver is fixed on the lower platform; the lower platform is fixedly connected to the lower platform adapter ring by a bolt pair; the upper part of the inner side surface of the star-shaped frame is provided with a plurality of sets of flexible cable dual-drive mechanisms arranged along the circumference, and the flexible cable dual-drive mechanism includes a servo slide, a hoisting mechanism, a wire rope, an open cable segment mechanism and a slewing support bearing and a pulley arranged on the lower platform adapter ring vertically installed on the inner side of the star-shaped frame, and the wire rope of the flexible cable dual-drive mechanism passes through the pulley to suspend the feed platform on the star-shaped frame. The present invention uses a plurality of sets of flexible cable dual-drive mechanisms to realize the parallel drive of the lower platform, replacing the AB swivel mechanism and the rigid parallel mechanism of the existing feed cabin, so as to solve the technical problems of the small control angle and the large weight of the feed cabin existing in the existing feed cabin.

Description

Technical Field

[0001] The invention relates to astronomical equipment, and in particular to a positioning mechanism for positioning a FAST feed cabin. Background Art

[0002] The Five-hundred-meter Aperture Spherical radioTelescope (FAST) is the world's largest single-aperture radio telescope, with three independent innovations: using Guizhou's natural karst pit as the site; actively deforming the reflecting surface; using a flexible lightweight mechanism dragged by six cables in parallel to drag the feed cabin to achieve primary cable drive; and using the AB rotating shaft mechanism and Stewart parallel mechanism in the feed cabin to achieve secondary fine-tuning of the feed position, thereby achieving high-precision positioning of the feed.

[0003] The FAST reflector can achieve instantaneous active deformation of the 300-meter aperture reflector, from a spherical surface to a parabola, ensuring that the parabola always points to the celestial body to be observed and focusing the radio wave signals from the celestial body. At the same time, the feed receiver at the focal position receives and processes the radio wave signals, and this process is continuous.

[0004] In order to receive radio waves, the feed receiver is installed in the feed cabin, and a feed support system is used to achieve positioning at an altitude of 140m and a range of 207m. Six feed support towers over 100 meters high are evenly distributed on the circumference of a 600-meter diameter circle on the outer edge of the reflection surface. Each tower supports a 46mm diameter steel wire rope, which is driven by a driving winch at the bottom of each tower and reliably connected to the feed cabin through the ground guide pulley, the tower center cable channel, and the tower top guide pulley mechanism. The six steel wire ropes move in parallel to drag the feed cabin for preliminary positioning of the astronomical tracking observation trajectory.

[0005] The feed cabin is the main equipment that carries the feed receiver and further fine-tunes its position and attitude. It mainly includes a star frame, an AB axis mechanism, a Stewart platform, a multi-beam receiver steering device, a cabin cover and other ancillary equipment / facilities. The overall size of the feed cabin is 13 meters in diameter, 6 meters in height, and weighs about 30 tons. The AB axis mechanism is a mechanism that rotates two-dimensionally around the orthogonal A and B axes, mainly including: the A axis and its drive, the B axis and its drive, and the AB axis swivel. The Stewart platform is a six-bar parallel mechanism, including an upper platform, a lower platform adapter ring, a lower platform, a driving leg, a ball joint and a Hooke's joint. The upper platform is equipped with a B-axis interface, and the lower platform needs to carry the feed receiver and its ancillary mechanisms. The multi-beam receiver steering device is a device on the Stewart lower platform that adjusts the multi-beam receiver to rotate a certain angle around its normal direction.

[0006] When the FAST reflector is actively deformed, six 100-meter-high towers evenly distributed on a 600-meter-diameter circle support six steel cables. The six cables form a cable-pulling parallel mechanism as the first-level control mechanism, which drags the 30-ton FAST feed cabin to perform astronomical tracking movements within a range of 200 meters at an altitude of 150 meters. The control accuracy that can be achieved by cable drive (the central control point is the intersection of the A axis and the B axis): spatial position error ≤RMS 48mm, maximum spatial attitude error ≤1°; the AB axis mechanism is the second-level control mechanism, which compensates for the angle between the normal of the Stewart upper platform and the central axis of the star frame. The current maximum rotation angle is designed to be ±18°. The Stewart platform, as the third-level control mechanism, only compensates for the residual control errors of the first and second levels and the vibration of the feed cabin, and fine-tunes the feed position and attitude during tracking observations. The final requirement is that the real-time spatial position error of the FAST feed is ≤RMS10mm; high-precision pointing and tracking observations of celestial bodies are achieved. Summary of the invention

[0007] The purpose of the present invention is to provide a FAST feed cabin positioning mechanism which has a novel and unique structure, is easy to use, and can effectively reduce the overall weight of the feed cabin and improve the feed positioning control angle; the specific technical scheme is:

[0008] A FAST feed cabin positioning mechanism comprises a star-shaped frame and a feed platform, wherein the feed platform comprises a lower platform and a lower platform adapter ring, and a multi-beam feed receiver is fixed on the lower platform; the lower platform is fixedly connected to the lower platform adapter ring through a bolt pair; a plurality of sets of flexible cable dual-drive mechanisms distributed along the circumference are arranged on the upper inner side surface of the star-shaped frame, and the flexible cable dual-drive mechanisms comprise a servo slide and a rope vertically installed on the inner side of the star frame, a winch mechanism, an open cable segment mechanism, and a slewing support bearing and a pulley arranged on the lower platform adapter ring, and a steel wire rope of the winch mechanism passes through the pulley to suspend the feed platform on the star frame.

[0009] Furthermore, the flexible cable dual drive mechanism is divided into 6 sets.

[0010] Furthermore, the hoisting mechanisms of the six sets of flexible rope dual-drive mechanisms are evenly distributed along the circumference of the upper platform drum.

[0011] Furthermore, the components consisting of the slewing support bearings and pulley mechanisms of the six sets of flexible cable dual drive mechanisms are distributed circumferentially along the lower platform distribution circle and are arranged in three pairs, wherein each pair of pulley mechanisms is adjacent, and the three pairs of pulley mechanisms are evenly distributed circumferentially along the lower platform distribution circle at intervals of 120°.

[0012] Furthermore, the flexible cable dual-drive mechanism also includes a servo slide arranged in the vertical direction, and the servo slide is provided with a sliding workbench that can slide in a controlled manner; the moving end of the wire rope is wound around the drum of the winch, and the stationary end of the wire rope is fixed on the mounting seat plate of the servo slide, and is stationary relative to the star-shaped frame, and the drum is installed on the sliding workbench, and the moving end of the wire rope is anchored on the drum; or the stationary end of the wire rope is anchored on the sliding workbench, and the drum is fixed on the mounting seat plate of the servo slide.

[0013] Furthermore, the servo slide is provided with a limit member and a zero position switch for limiting the moving distance of the sliding workbench.

[0014] Furthermore, the hoisting mechanism is provided with a brake mechanism.

[0015] Furthermore, one side of the drum of the winch is a large gear as a driving disc, and the other side is a brake disc of the brake mechanism.

[0016] The present invention relates to a FAST feed cabin positioning mechanism, which is an upgrade and transformation of the feed cabin. The feed cabin positioning mechanism is composed of a star frame, 6 sets of flexible cable dual drive mechanisms, a lower platform adapter ring, a lower platform, a feed receiver, etc. The flexible cable dual drive mechanism is composed of a vertically installed servo slide, a winch mechanism, a wire rope, a slewing support bearing and a pulley assembly, and an open cable segment mechanism, with a total of 12 drive motors. The upper platform is set as the plane where the upper travel limit position of the 6 sets of servo slides passes through the center of the 6 sets of drums, and the plane where the center of the 6 sets of pulleys connected to the lower platform is set as the lower platform plane. The mechanism realizes the pitch angle change of the lower platform by the retraction and release of 6 ropes (feed source angle compensation is realized by trajectory planning, referred to as angle control in the text), and the mechanism realizes the pointing tracking of the feed cabin for radio signals; the platform is quickly fine-tuned by the linear motion of the sliding worktable of the 6 sets of servo slides (the 5 degrees of freedom of the lower platform are fine-tuned by the linear motion of the sliding worktable of the six sets of servo slides under secondary control, referred to as fine-tuning control in the text). BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the overall structure of the FAST feed cabin positioning mechanism provided by the present invention;

[0018] Figure 2 A top view of the overall structure of the FAST feed cabin positioning mechanism provided by the present invention;

[0019] Figure 3 A schematic diagram of a flexible cable dual drive mechanism assembly provided by the present invention;

[0020] Figure 4 A schematic diagram of a servo slide provided by the present invention;

[0021] Figure 5A schematic diagram of a hoisting mechanism provided by the present invention;

[0022] Figure 6 A schematic diagram of a pulley mechanism provided by the present invention;

[0023] Figure 7 A schematic diagram of an open cable socket mechanism provided by the present invention;

[0024] In the figure: 1. Multi-beam feed receiver; 2. Lower platform adapter ring; 3. Lower platform; 4. Star frame cabin cable anchoring head seat; 5. Star frame; 6. Soft cable dual drive mechanism; 7. Upper platform drum distribution circle; 8. Lower platform pulley distribution circle; 9. Servo slide mounting seat plate; 10. Open cable segment mechanism; 11. Servo slide; 12. Winch mechanism; 13. Wire rope; 14. Pulley mechanism; 15. Slewing support bearing; 16. Servo slide guide seat; 17. Ball screw mechanism; 18. Sliding workbench; 1 9. Linear rolling guide; 20. Servo motor; 21. Synchronous belt; 22. Drum support; 23. Pinion drive mechanism; 24. Brake; 25. Drum support; 26. Drum shaft; 27. Brake disc; 28. Drum; 29. ​​Large gear; 30. Cylindrical roller bearing; 31. Pulley seat; 32. Pulley axial retaining ring; 33. Small round nut; 34. Sliding bearing sleeve; 35. Pulley shaft; 36. Pulley; 37. Open cable segment; 38. Pin assembly; 39. Cross coupling block; 40. Anchor seat. DETAILED DESCRIPTION

[0025] The present invention is described more fully below using embodiments. The present invention can be embodied in many different forms and should not be construed as being limited to the exemplary embodiments described herein.

[0026] For ease of description, spatially relative terms such as "upper", "lower", "left", "right", etc. may be used herein to describe the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the elements described as being "below" other elements or features will be positioned "above" other elements or features. Therefore, the exemplary term "lower" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here can be interpreted accordingly.

[0027] like Figure 1 , Figure 2As shown, the FAST feed cabin positioning mechanism in this embodiment includes a star frame 5, a flexible cable dual drive mechanism 6 and a feed platform, etc. The feed platform includes a lower platform 3 and a lower platform adapter ring 2, and the multi-beam feed receiver 1 is fixed on the lower platform 3; the upper part of the inner side surface of the star frame 5 is provided with 6 sets of hoisting mechanisms 12 evenly distributed along the upper platform drum distribution circle, and the flexible cable dual drive mechanism 6 includes a component composed of a slewing support bearing and a pulley mechanism provided on the lower platform adapter ring. The steel wire rope of the flexible cable dual drive mechanism passes through the pulley of the pulley mechanism and is fixedly connected to the servo slide mounting seat plate 9, and the mounting seat plate 9 is fixedly connected to the star frame 5, and the feed platform is suspended on the star frame. The length of the steel wire rope shown is changed by the hoisting mechanism to adjust the spatial position and angle of the feed platform. The center of the upper platform drum distribution circle is on the central axis of the star frame 5. The number of hoisting mechanisms 12 is not limited to 6, and can also be 3 or 4; it should be greater than 3. Multiple steel wire ropes 13 are used to pull from multiple directions to adjust the spatial state of the multi-beam feed receiver 1, including the spatial position and angle, which can fully meet the tracking speed of the telescope focus. The pitch angle adjustment range of the multi-beam feed receiver 1 can reach ±25°, which is far higher than the ±18° rotation angle of the AB axis in the existing feed cabin of FAST. Three star-shaped frame cabin cable anchoring head seats 4 are set on the outer edge of the star-shaped frame 5 for connecting to the support tower through flexible cables.

[0028] The hoisting mechanism 12 is divided into 6 sets. The 6 sets of hoisting mechanisms 12 are evenly distributed along the central distribution circle of the upper platform drum; and the components composed of the pulley mechanism 14 and the slewing support bearing 15 in each set of the soft cable dual drive mechanism 6 are distributed along the central distribution circle of the pulley of the lower platform, the pulley mechanism 14 is fixed to the inner ring of the slewing support bearing 15 by bolts, and the outer ring of the slewing support bearing 15 is fixed to the lower platform adapter ring 2 by bolts, and the pulley mechanism 14 can rotate around the center line of the slewing support bearing 15. The components composed of the pulley mechanism 14 and the slewing support bearing 15 are arranged in 3 pairs, and the components composed of each pair of pulley mechanisms 14 and slewing support bearings 15 are close to each other, and the 3 pairs of pulley mechanisms 14 and slewing support bearings 15 are evenly distributed along the distribution circle of the lower platform at an interval of 120°. It is convenient to adjust the spatial position and angle of the feed platform. Of course, it can also be unevenly distributed, but it should be possible to adjust the spatial position and angle of the feed platform, and the control algorithm of the unevenly distributed scheme will be more complicated.

[0029] In order to eliminate the influence of wind or soft rope shaking and other vibrations caused during the transmission process, the soft rope dual drive mechanism 6 also includes a servo slide 11 arranged in the vertical direction, and the servo slide 11 is provided with a sliding workbench 18 that can slide in a controlled manner; the moving end of the wire rope is wound on the drum of the winch, and the static end of the wire rope is anchored on the servo slide mounting seat plate 9 and is stationary relative to the star frame. Alternatively, the static end of the wire rope 13 is anchored on the sliding workbench 18, and the drum is fixed on the servo slide mounting seat plate 9.

[0030] The servo slide 11 is fixed on the servo slide mounting base plate 9 , and the servo slide mounting base plate 9 is welded to the upper and lower ball nodes of the star frame as a whole, serving as a support for the servo slide 11 .

[0031] like Figure 3 As shown, the flexible cable dual drive mechanism 6 is composed of a servo slide 11, a hoisting mechanism 12, a wire rope 13, a pulley mechanism 14, a slewing support bearing 15 and an open cable segment mechanism 10. The servo slide 11 is fixedly connected to the servo slide mounting base plate 9 by bolts. The hoisting mechanism 12 is fixedly connected to the sliding workbench 18 of the servo slide by bolts, and moves linearly up and down with the sliding workbench 18. The pulley mechanism 14 is fixedly connected to the inner ring of the slewing support bearing 15 by bolts, and the outer ring of the slewing support bearing 15 is fixedly connected to the lower platform adapter ring 2 by bolts, and the pulley mechanism 14 can rotate around the axis of the slewing support bearing 15. The anchor seat 40 of the open cable segment mechanism 10 is fixedly connected to the servo slide mounting base plate 9 by bolts, and is located at the lower limit position of the servo slide. One end of the steel wire rope 13 is thermally anchored to the cable node of the open cable node mechanism, passes through the pulley mechanism 14, and is wound on the drum 28 of the hoisting mechanism 12. The steel wire rope 13 is anchored on the drum 28 at the left end of the drum. The steel wire rope 13 is a bottom-out rope structure layout to reduce the overturning moment of the drum support 25. The cable dual drive mechanism 6 is connected to the lower platform adapter ring 2 through the steel wire rope 13, the pulley mechanism 14, and the slewing support bearing 15 to form a flexible cable parallel mechanism.

[0032] like Figure 4 As shown, the servo slide 11 is mainly composed of a servo slide guide seat 16, a ball screw mechanism 17, a sliding table 18, two linear rolling guides 19, a servo motor 20 and a synchronous belt 21. The servo motor 20 transmits the rotation to the ball screw 17 through the active synchronous pulley fixedly connected to its output shaft and the synchronous belt 21 and the driven synchronous pulley fixedly connected to the ball screw 17. The ball screw 17 drives the sliding table 18 fixed to the ball screw nut to make up and down linear motion along the two linear rolling guides 19. The sliding table 18 is divided into an upstroke and a downstroke by the zero position switch in the middle. The upstroke and the downstroke can be the same in length or slightly different. The servo slide 11 drives the winch mechanism 12 on the sliding table 18 to move up and down quickly along the linear rolling guide 19, and the dynamic response is fast.

[0033] like Figure 5 As shown, the hoisting mechanism 12 includes a drum support 22, a drum support 25, a large gear 29, a pinion drive mechanism 23, a drum 28, a drum shaft 26 and a cylindrical roller bearing 30. In order to improve the stability of the feed platform control, the hoisting mechanism is provided with a brake disc 27 and a brake 24 as a brake mechanism; when reaching the ideal position, the length of the wire rope is fixed by the brake mechanism to improve the stability of the system. The brake disc 27, the large gear 29 and the drum are fixed together by bolts, and the gear shaft 26 cooperates with the brake disc 27 and the large gear 29 hole shaft, and is stopped by a flat key and fixed together with the drum component. The drum support 22 and the drum support 25 support the two ends of the drum shaft 26 through two sets of cylindrical roller bearings 30, and the drum shaft 26 can rotate around its own axis. The bottom surface of the drum support 22 and the drum support 25 fits with the sliding workbench 18 and is fixed by bolts. The bottom surface of the seat of the pinion drive mechanism 23 fits with the sliding workbench 18 and is fixedly connected by bolts. The pinion drive mechanism 23 meshes with the large gear 29, driving the large gear 29 to drive the drum to rotate. The bottom surface of the seat of the brake 24 fits with the sliding workbench 18 and is fixedly connected to the sliding workbench 18 by bolts. The brake 24 is paired with a brake disc 27, and the brake pad of the brake 24 clamps the brake disc 27 to brake the drum; when the brake pad is released, the brake disc 27 is released. In the figure, the large gear serves as a drive disc and is arranged on the left side, and can also be arranged on the right side. One side of the drum of the winch is a gear as a drive disc, and the other side is a brake disc of the brake mechanism, and the structure is simpler.

[0034] like Figure 6 As shown, the pulley mechanism 14 is composed of a pulley seat 31, two pulley axial retaining rings 32, a small round nut 33, a sliding bearing sleeve 34, a pulley shaft 35 and a pulley 36. The bottom plate of the pulley seat 31 cooperates with the inner ring end face of the slewing support bearing 15 and is fixed by bolts; the bearing seat of the slewing support bearing 15 is fixed on the lower platform adapter ring 2. The pulley mechanism 14 can rotate around the axis of the slewing support bearing 15 to adapt to the pulley 36 rotating with the wire rope 13 when the flexible cable parallel mechanism is working.

[0035] like Figure 7 As shown, the open cable joint mechanism 10 is a Hook hinge mechanism, and the cross coupling block 39 has two mutually perpendicular holes, which are respectively connected to the holes of the anchor seat 40 and the holes of the open cable joint 37 through two sets of pin shaft assemblies 38. The wire rope 13 is thermally anchored to the open cable joint 37, and the Hook hinge mechanism can make the wire rope 13 adapt to the angle change when the wire rope 13 is retracted and released, reduce bending, and prevent the wire rope 13 from being repeatedly bent and damaged.

[0036] When in use, the hoisting mechanism 12 is driven by the servo motor 20 to move to the vicinity of the midpoint zero position of the stroke, so as to facilitate the rapid fine adjustment of the spatial state of the multi-beam feed receiver 1 according to the offset signal fed back by the acceleration sensor or laser interferometer, eliminate the jitter, and stabilize the multi-beam feed receiver 1 at the target position. The pinion drive mechanism 23 of the 6 sets of flexible cable dual drive mechanisms 6 drives the drum 28 to rotate and slowly contract or loosen the wire rope 13 wound on the drum 28 according to the instructions of the control unit, and cooperates with each other to adjust the phase center point of the multi-beam feed receiver 1 to the vicinity of the focus of the reflection surface, and the feed center line is parallel to the focal axis of the reflection surface. The servo motors 20 of the slides of the 6 sets of flexible cable dual drive mechanisms 6 drive the hoisting mechanism 12 to move rapidly upward or downward along the linear rolling guide rail 19 according to the instructions of the control unit, and quickly fine-tune the phase center position of the multi-beam feed receiver 1 to the vicinity of the corner point of the reflection surface and the feed center line is parallel to the focal axis of the reflection surface.

[0037] The present invention relates to a FAST feed cabin positioning mechanism, which is an upgrade and transformation of the feed cabin. The FAST feed cabin positioning mechanism is composed of a star frame, 6 sets of soft cable dual drive mechanisms, a lower platform adapter ring, a lower platform, a feed receiver, etc. The soft cable dual drive mechanism is composed of a vertically installed servo slide, a winch mechanism, a wire rope, a pulley mechanism, a slewing support bearing and an open cable segment mechanism, etc., with a total of 12 drive motors. The plane where the stroke limit position of the 6 sets of servo slides passes through the center of the 6 sets of drums is set as the upper platform plane, and the plane where the center of the 6 sets of pulleys connected to the lower platform is set as the lower platform plane. The mechanism realizes the pitch angle change of the lower platform by the retraction and release of 6 ropes (feed source angle compensation is realized by trajectory planning, which is referred to as angle control in the text), and the platform is fine-tuned by the linear motion of the sliding worktable of the 6 sets of servo slides (under secondary control, the 5 degrees of freedom of the lower platform are fine-tuned by the linear motion of the sliding worktable of the six sets of servo slides, which is referred to as fine-tuning control in the text); the scheme of the present application reduces the total weight of the feed cabin to 26 tons.

[0038] The present invention uses 6 sets of flexible cable dual drive mechanisms to realize parallel drive of the lower platform, replacing the AB swivel mechanism and rigid parallel mechanism of the existing feed cabin, so as to solve the technical problems of the existing feed cabin such as small control angle and heavy weight of the feed cabin.

[0039] The above examples are only used to illustrate the present invention. In addition, there are many different implementations. These implementations are all conceivable by those skilled in the art after understanding the concept of the present invention. Therefore, they are not listed here one by one.

Claims

1. A FAST feed cabin positioning mechanism, comprising a star-shaped frame and a feed platform, wherein the feed platform comprises a lower platform and a lower platform adapter ring, and a multi-beam feed receiver is fixed on the lower platform; the lower platform is fixedly connected to the lower platform adapter ring by a bolt pair; characterized in that: The upper part of the inner side surface of the star-shaped frame is provided with a plurality of sets of flexible cable dual-drive mechanisms arranged along the circumference, and the flexible cable dual-drive mechanisms include a servo slide vertically installed on the inner side of the star frame, a winch mechanism, an open cable segment mechanism and a slewing support bearing and a pulley mechanism arranged on the lower platform adapter ring; the wire rope of the winch mechanism passes through the pulley to suspend the feed platform on the star frame; the servo slide is fixedly connected to the servo slide mounting base plate by bolts; the winch mechanism is fixedly connected to the sliding workbench of the servo slide by bolts, and moves with the sliding work The platform makes linear motion up and down; the pulley mechanism is fixedly connected to the inner ring of the slewing support bearing by bolts, the outer ring of the slewing support bearing is fixedly connected to the lower platform adapter ring by bolts, and the pulley mechanism rotates around the axis of the slewing support bearing; the anchor seat of the open cable segment mechanism is fixedly connected to the servo slide mounting seat plate by bolts, and is located at the lower limit position of the servo slide; one end of the wire rope is thermally anchored to the cable segment of the open cable segment mechanism, passes through the pulley mechanism, and is wound on the drum of the winch mechanism, and the wire rope is anchored to the drum at the left end of the drum, and the wire rope is arranged in a bottom-out rope structure.

2. The FAST feed cabin positioning mechanism according to claim 1, characterized in that: The flexible cable dual-drive mechanism is divided into 6 sets.

3. The FAST feed cabin positioning mechanism according to claim 2, characterized in that: The servo slides and winch mechanisms of the six sets of flexible rope dual-drive mechanisms are evenly distributed along the circumference of the upper platform drum.

4. The FAST feed cabin positioning mechanism according to claim 2, characterized in that: The components consisting of the slewing support bearings and pulley mechanisms of the six sets of flexible cable dual drive mechanisms are distributed circumferentially along the lower platform distribution circle and are arranged in three pairs, wherein each pair of pulley mechanisms is adjacent, and the three pairs of pulley mechanisms are evenly distributed circumferentially along the lower platform distribution circle at intervals of 120°.

5. The FAST feed cabin positioning mechanism according to claim 1, characterized in that: The servo slide is provided with a sliding workbench that can slide in a controlled manner; the moving end of the wire rope is wound around the drum of the hoisting mechanism, and the stationary end of the wire rope is fixed on the mounting seat plate of the servo slide and is stationary relative to the star-shaped frame; the drum is installed on the sliding workbench, and the moving end of the wire rope is anchored on the drum.

6. The FAST feed cabin positioning mechanism according to claim 5, characterized in that: The servo slide is provided with a limiter and a zero position switch for limiting the moving distance of the sliding workbench.

7. The FAST feed cabin positioning mechanism according to claim 1, characterized in that: The hoisting mechanism is provided with a brake mechanism.

8. The FAST feed cabin positioning mechanism according to claim 7, characterized in that: One side of the drum of the hoisting mechanism is a large gear as a driving disc, and the other side is a brake disc of the brake mechanism.

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