Spring-based rotational stiffness simulation platform

Abstract

This invention relates to the field of space mechanics simulation technology, specifically to a spring-based rotational stiffness simulation platform. The platform includes a support frame and a rotational input end, a motion conversion mechanism, and a rotational stiffness variable mechanism, all mounted on the support frame. The motion conversion mechanism is connected to both the rotational input end and the rotational stiffness variable mechanism. Rotation input from the input end is transmitted to the motion conversion mechanism, which converts the rotation into translation. The rotational stiffness variable mechanism adjusts its own stiffness by changing the effective number of spring coils, and this adjustment acts on the motion conversion mechanism to change the rotational stiffness of the input end, thus achieving adjustment of the rotational stiffness. The simulation platform provided by this invention can simulate the stiffness changes of the upper arm during the movement of the combined upper and lower arms of a space station on the ground, and react on the lower arm, thereby laying the foundation for studying the disturbance motion laws occurring within the combined arms under the combined movement of the upper and lower arms of a space station.

Description

Technical Field

[0001] This invention relates to the field of space mechanics simulation technology, specifically providing a spring-based rotational stiffness simulation platform. Background Technology

[0002] With the completion of China's space station, increasingly diverse and complex space missions need to be accomplished. The robotic arms on the space station play an increasingly important role in various operational tasks, from assisting astronauts with extravehicular activities to performing delicate operations such as carrying, transferring, and inserting / removing various payloads. These tasks require the robotic arms to meet various dynamic performance requirements.

[0003] The robotic arm system on the space station consists of two parts: a large arm and a small arm. They can work independently or combine to expand the workspace, addressing needs that require not only range transfer but also precise localized operations, significantly improving the mobility of the space robotic arm system. For dynamic performance studies of the combined arm on Earth, the large arm, serving as the base, can generally be considered equivalent to a flexible base, greatly reducing the complexity of the experimental system.

[0004] Currently designed flexible bases have variable rotational stiffness, but not real-time variable stiffness. They can only pre-adjust the base to match the rotational stiffness of a certain configuration of the upper arm, and then the forearm moves under this set of base stiffness characteristics. That is, they simulate a system scenario where the upper arm remains fixed in a certain configuration while the forearm moves. They cannot realize that the rotational stiffness of the flexible base changes in real time under human control during the movement of the forearm. In other words, they cannot simulate a system scenario where the upper arm moves while the forearm moves.

[0005] Therefore, there is an urgent need for a rotational stiffness simulation platform that can simulate the real-time changes in rotational stiffness. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a spring-based rotational stiffness simulation platform that can simulate the simultaneous movement of the large and small arms of a space station. The large arm serves as the base for the small arm, and the rotational stiffness changes caused by the configuration changes during its movement allow for the study of the disturbance motion patterns occurring within the combined arms under the combined movement of the large and small arms of the space station.

[0007] The present invention provides a spring-based rotational stiffness simulation platform, comprising a platform support frame and a rotational input end, a motion conversion mechanism, and a rotational stiffness variable mechanism respectively mounted on the platform support frame; wherein, the motion conversion mechanism includes a second coupling, a sector gear, and a sliding assembly; wherein, one end of the second coupling is fixedly connected to the rotational input end via a rotating shaft, and the other end of the second coupling is fixedly connected to the sector gear via a rotating shaft; the sliding assembly includes a slidingly engaged slider and a slide rail, and a rack is machined on one side of the slider; the rotation of the rotational input end is transmitted to the sector gear via the second coupling, and is converted into translational motion of the slider on the slide rail through the meshing of the sector gear and the rack; the rotational stiffness variable mechanism includes a top cone seat and two stiffness variable adjustment units, the two stiffness variable adjustment units respectively abutting the top cone seat on both sides, and the top cone seat is fixedly mounted on the slider; each of the two stiffness variable adjustment units includes a drive motor, a first The system comprises a coupling, ball spline, rotating shaft, spring, base, snap-fit ​​component, bearing, bushing, and end cap. The drive motor is fixed to the platform support frame. The output shaft of the drive motor is connected to the spline shaft of the ball spline via a first coupling. The flange of the ball spline is connected to the rotating shaft. The bushing is fitted onto the end of the rotating shaft. The spring and bearing are fitted onto both ends of the bushing. The end cap is fitted onto the outside of the spring and bearing. Top cone holes that mate with the top cone are formed on the end cap and the top cone seat, respectively. The base includes a T-shaped base and a sleeve. The T-shaped base is mounted on the platform support frame and fixedly connected to the sleeve. The sleeve is fitted onto the outside of the spring. The snap-fit ​​component is fixedly connected to the sleeve and snaps into the inside of the spring, controlling the rotation of the drive motor's output shaft. The rotation is transmitted sequentially through the first coupling, ball spline, rotating shaft, and bushing to the spring. The spring abuts against the snap-fit ​​component and rotates radially, changing the effective number of turns and adjusting the stiffness of the motion conversion mechanism.

[0008] Preferably, the locking component is a limiting bolt, and an adjustment hole is provided on the sleeve for adjusting the position of the limiting bolt. The head of the limiting bolt is locked on the outside of the adjustment hole, and the screw of the limiting bolt passes downward through the adjustment hole and is locked into the inside of the spring.

[0009] Preferably, the snap-fit ​​component includes a snap cone and a snap cone block, which are integral or separate structures. The snap cone block is fixed to the sleeve by a fastening bolt. The snap cone block and the sleeve are respectively provided with waist-shaped holes for adjusting the position of the fastening bolt. The sleeve is also provided with a clearance hole. The snap cone passes downward through the clearance hole and then snaps into the inside of the spring.

[0010] Preferably, the T-shaped base is fixedly mounted on the platform support frame by two L-shaped connecting blocks, and the gap between the two L-shaped connecting blocks allows the slide rail to pass through.

[0011] Preferably, the platform support frame includes an upper platform, a lower platform, and a profile, with the profile supported between the upper and lower platforms, and the slide rail, drive motor, and T-shaped base respectively fixed on the lower platform.

[0012] Preferably, the rotary input end includes a rotatably connected triangular connecting frame and a U-shaped frame. The triangular connecting frame is located above the U-shaped frame and has a connecting hole for connecting to a power source. The two ends of the U-shaped frame have outwardly formed ridges, which are fixed to the upper platform by screws. A rolling bearing is installed at the U-shaped bottom of the U-shaped frame. One end of the second coupling is fixedly connected to the triangular connecting frame through a rotating shaft, and the rotating shaft and the U-shaped frame are rotatably engaged by the rolling bearing.

[0013] Preferably, the drive motor is fixedly mounted on the lower platform via a motor bracket.

[0014] Compared with the prior art, the simulation platform provided by the present invention can simulate the stiffness change of the upper arm during the movement of the space station's upper and lower arms when they are combined on the ground, and react on the lower arm, thereby laying the foundation for studying the disturbance motion law that occurs in the combined arm when the upper and lower arms of the space station move together. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of a spring-based rotational stiffness simulation platform according to an embodiment of the present invention.

[0016] Figure 2 This is a partial structural schematic diagram from a first-view perspective of a spring-based rotational stiffness simulation platform provided according to an embodiment of the present invention.

[0017] Figure 3 This is a partial structural schematic diagram from a second perspective of a spring-based rotational stiffness simulation platform provided according to an embodiment of the present invention.

[0018] Figure 4 This is a schematic diagram of the overall structure of the variable stiffness adjustment unit provided in an embodiment of the present invention;

[0019] Figure 5 This is a cross-sectional structural schematic diagram of the variable stiffness adjustment unit provided in an embodiment of the present invention.

[0020] The reference numerals in the drawings include: upper platform 101, lower platform 102, profile 103, triangular connecting frame 201, U-shaped frame 202, connecting hole 203, edge 204, second coupling 301, sector gear 302, slide rail 303, slider 304, top cone seat 401, top cone 402, drive motor 403, first coupling 404, ball spline 405, rotating shaft 406, spring 407, base 408, T-shaped base 409, sleeve 410, snap fastener 411, snap cone 412, snap cone block 413, fastening bolt 414, bearing 415, bushing 416, end cover 417, motor bracket 418, and L-shaped connecting block 419. Detailed Implementation

[0021] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0023] This invention provides a spring-based rotational stiffness simulation platform, which can simulate the stiffness change in rotational degrees of freedom at the connection point of the combined arms when the upper arm serves as the base of the lower arm.

[0024] like Figures 1-5 As shown, the spring-based rotational stiffness simulation platform includes a platform support frame, a rotation input end, a motion conversion mechanism, and a rotational stiffness variable mechanism. The rotation input end, motion conversion mechanism, and rotational stiffness variable mechanism are respectively mounted on the platform support frame. The motion conversion mechanism is connected to the rotation input end and the rotational stiffness variable mechanism respectively. The rotation input from the rotation input end is transmitted to the motion conversion mechanism, which converts the rotation of the rotation input end into translation. The rotational stiffness variable mechanism adjusts its own stiffness by changing the effective number of spring coils and acts on the motion conversion mechanism to change the rotational stiffness of the rotation input end.

[0025] The platform support frame includes an upper platform 101, a lower platform 102, and a profile 103, with the profile 103 supporting the upper platform 101 and the lower platform 102.

[0026] The rotation input end includes a triangular connecting frame 201 and a U-shaped frame 202. The U-shaped frame 202 is located below the triangular connecting frame 201. The triangular connecting frame 201 can rotate relative to the U-shaped frame 202. A connecting hole 203 is provided on the triangular connecting frame 201 for connecting to an external power source. The power source inputs rotation to the rotation input end to simulate the horizontal rotation of the forearm. A platform edge 204 is formed outward at both ends of the U-shaped frame 202. The platform edge 204 is fixed to the upper platform 101 by screws. A rolling bearing is installed at the U-shaped bottom of the U-shaped frame 202.

[0027] Second coupling 301, sector gear 302, slide rail 303, slider 304

[0028] The motion conversion mechanism includes a second coupling 301, a sector gear 302, and a sliding assembly. The sliding assembly includes a slide rail 303 and a slider 304. The slide rail 303 is fixedly mounted on the lower platform 102, and the slider 304 slides linearly on the slide rail 303. A rack is machined on the side of the slider 304, which meshes with the sector gear 302 for transmission. The two ends of the second coupling 301 are respectively connected to rotating shafts. The rotating shaft connected to the upper end of the second coupling 301 is fixedly connected to the triangular connecting frame 201, and the rotating shaft connected to the lower end of the second coupling 301 is fixedly connected to the sector gear 302, thereby synchronously rotating the input end and the sector gear 302. The rotating shaft connected to the upper end of the second coupling 301 achieves rotational engagement with the U-shaped frame 202 through rolling bearings.

[0029] When the input end rotates horizontally, it drives the second coupling 301 and the sector gear 302 to rotate. Through the meshing transmission between the sector gear 302 and the rack on the slider 304, the horizontal rotation of the input end is converted into the linear sliding of the slider 304 on the slide rail 303.

[0030] The rotational variable stiffness mechanism includes a top cone seat 401 and two identical variable stiffness adjustment units. Top cone holes are machined on two opposite surfaces of the top cone seat 401 for mounting top cones 402. The two variable stiffness adjustment units abut against the two top cones 402 respectively. The top cone seat 401 is fixed to a slider 304, which is subjected to forces in two directions; that is, the translational motion of the slider 304 is disturbed by the two variable stiffness adjustment units. By changing the output stiffness of the variable stiffness adjustment units in real time, the rotational stiffness of the rotational input end is controllable and time-varying.

[0031] The variable stiffness adjustment unit includes a drive motor 403, a first coupling 404, a ball spline 405, a rotating shaft 406, a spring 407, a base 408, a snap-fit ​​component 411, a bearing 415, a bushing 416, and an end cover 417. The drive motor 403 is fixed on the lower platform 102 by a motor bracket 418. The output shaft of the drive motor 403 is connected to the spline shaft of the ball spline 405 through the first coupling 404. The flange of the ball spline 405... Connected to the rotating shaft 406, a bushing 416 is fitted onto the end of the rotating shaft 406. A spring 407 and a bearing 415 are respectively fitted onto both ends of the bushing 416. An end cap 417 is fitted onto the bushing 416 and located outside the spring 407 and the bearing 415. The end cap 417 abuts against the top cone 402. The inner ring of the bearing 415 contacts the bushing 416, and the outer ring of the bearing 415 contacts the end cap 417. The base 408 includes a T-shaped structure that can be integral or split. The T-shaped base 409 and sleeve 410 are fixedly mounted on the lower platform 102 by two L-shaped connecting blocks 419, which support and fix the sleeve 410. The two L-shaped connecting blocks 419 are spaced apart, with a gap in the middle for the slide rail 303 to pass through. The sleeve 410 is sleeved on the outside of the spring 407. The snap-fit ​​component 411 includes a snap cone 412 and a snap cone block 413, which are integral or separate structures. The snap cone block 413 is fastened by bolts 4. 14 is fixed on the outside of sleeve 410. The snap cone 412 passes through sleeve 410 and is inserted into the inside of spring 407. The output shaft of the control drive motor 403 rotates and is transmitted to spring 407 in sequence through first coupling 404, ball spline 405, rotating shaft 406, and bushing 416. Spring 407 abuts against snap cone 412 and rotates radially, thereby changing the effective number of turns of spring 407 and realizing the time-varying stiffness output of end cover 417 to top cone seat 401.

[0032] In order to adjust the position of the snap cone 412, the snap cone block 413 and the sleeve 410 are respectively provided with waist-shaped holes for adjusting the position of the fastening bolt 414. The sleeve 410 is also provided with a clearance hole. The snap cone 412 passes downward through the clearance hole and then gets into the inside of the spring 407.

[0033] As an alternative, the snap-fit ​​411 can also be a limiting bolt with an adjustment hole on the sleeve 410. The head of the limiting bolt is snapped on the outside of the adjustment hole, and the screw of the limiting bolt passes downward through the adjustment hole and is snapped into the inside of the spring 407. The screw is then locked onto the sleeve 410 by a nut.

[0034] This invention transmits rotation through a rotation input end. A motion conversion mechanism then transmits and converts the rotational force to a rotational variable stiffness mechanism. Due to interference from the rotational variable stiffness mechanism, the stiffness of the motion conversion mechanism is adjusted in real time by changing its stiffness. Finally, stiffness conversion controls the stiffness at the rotation input end. In this way, the real-time changing rotational stiffness of the boom during movement is simulated.

[0035] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0036] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A spring-based rotational stiffness simulation platform, characterized in that, It includes a platform support frame and a rotary input end, a motion conversion mechanism, and a rotary stiffness adjustment mechanism, each respectively mounted on the platform support frame; wherein, The motion conversion mechanism includes a second coupling, a sector gear, and a sliding assembly; wherein, one end of the second coupling is fixedly connected to the rotation input end via a rotating shaft, and the other end of the second coupling is fixedly connected to the sector gear via a rotating shaft; the sliding assembly includes a sliding slider and a slide rail; a rack is machined on one side of the slider; the rotation of the rotation input end is transmitted to the sector gear via the second coupling, and the meshing of the sector gear and the rack is converted into the translation of the slider on the slide rail; The rotational stiffness-changing mechanism includes a top cone seat and two stiffness-changing adjustment units. The two adjustment units are respectively supported on both sides of the top cone seat via the top cone, and the top cone seat is fixedly mounted on the slider. Each of the two stiffness-changing adjustment units includes a drive motor, a first coupling, a ball spline, a rotating shaft, a spring, a base, a snap-fit ​​component, a bearing, a bushing, and an end cap. The drive motor is fixed to the platform support frame. The output shaft of the drive motor is connected to the spline shaft of the ball spline via the first coupling. The flange of the ball spline is connected to the rotating shaft. The bushing is fitted onto the end of the rotating shaft. The spring and the bearing are respectively fitted onto both sides of the bushing. The end cap is fitted onto the outside of the spring and the bearing. Top cone holes that mate with the top cone are formed on the end cap and the top cone seat, respectively. The platform includes a T-shaped base and a sleeve. The T-shaped base is mounted on the platform support frame and fixedly connected to the sleeve. The sleeve is fitted onto the outside of the spring. The snap-fit ​​is fixedly connected to the sleeve and snaps into the inside of the spring, controlling the rotation of the output shaft of the drive motor. The rotation is transmitted sequentially through the first coupling, the ball spline, the rotating shaft, and the bushing to the spring. The spring abuts against the snap-fit ​​and rotates radially, changing the effective number of revolutions and adjusting the stiffness of the motion conversion mechanism.

2. The spring-based rotational stiffness simulation platform according to claim 1, characterized in that, The locking component is a limiting bolt. An adjustment hole is provided on the sleeve for adjusting the position of the limiting bolt. The head of the limiting bolt is locked on the outside of the adjustment hole, and the screw of the limiting bolt passes downward through the adjustment hole and is locked into the inside of the spring.

3. The spring-based rotational stiffness simulation platform according to claim 1, characterized in that, The snap-fit ​​component includes a snap cone and a snap cone block, which are either integral or separate. The snap cone block is fixed to the sleeve by a fastening bolt. The snap cone block and the sleeve are respectively provided with waist-shaped holes for adjusting the position of the fastening bolt. The sleeve is also provided with a clearance hole. The snap cone passes downward through the clearance hole and then snaps into the interior of the spring.

4. The spring-based rotational stiffness simulation platform according to claim 1, characterized in that, The T-shaped base is fixedly installed on the platform support frame by two L-shaped connecting blocks, and the gap between the two L-shaped connecting blocks allows the slide rail to pass through.

5. The spring-based rotational stiffness simulation platform according to any one of claims 1 to 4, characterized in that, The platform support frame includes an upper platform, a lower platform, and a profile. The profile is supported between the upper platform and the lower platform. The slide rail, the drive motor, and the T-shaped base are respectively fixed on the lower platform.

6. The spring-based rotational stiffness simulation platform according to claim 5, characterized in that, The rotary input end includes a triangular connecting frame and a U-shaped frame. The triangular connecting frame is located above the U-shaped frame and has a connecting hole for connecting to a power source. The two ends of the U-shaped frame have outwardly extending edges, which are fixed to the upper platform by screws. A rolling bearing is installed at the U-shaped bottom of the U-shaped frame. One end of the second coupling is fixedly connected to the triangular connecting frame via a rotating shaft, and the rotating shaft and the U-shaped frame are rotatably engaged by the rolling bearing.

7. The spring-based rotational stiffness simulation platform according to claim 5, characterized in that, The drive motor is fixedly mounted on the lower platform via a motor bracket.

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