Spring-based translational stiffness simulation platform

Abstract

This invention relates to the field of space mechanics simulation technology, specifically to a spring-based translational stiffness simulation platform. The platform includes a translational input end, a platform support frame, a translational transmission mechanism, and a translational stiffness-changing mechanism. The translational input end is fixed to the platform support frame, which is connected to both the translational transmission mechanism and the translational stiffness-changing mechanism. The translational input is transmitted to the platform support frame, which then undergoes translational motion under the action of the translational transmission mechanism. The translational stiffness-changing mechanism adjusts its own stiffness by changing the effective number of spring coils and acts on the platform support frame, thereby adjusting the translational stiffness of the translational input end. The simulation platform provided by this invention can simulate the stiffness change of a single translational degree of freedom of the upper arm during its movement when the upper and lower arms of a space station are combined, and then react on the lower arm, thus laying the foundation for studying the disturbance motion laws occurring within the combined arm 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 translational 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 translational stiffness, but not real-time variable stiffness. They can only pre-adjust the base to match the translational 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 in which the upper arm remains fixed in a certain configuration while the forearm moves. They cannot realize that the translational 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 in which the upper arm moves while the forearm moves.

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

[0006] To address the aforementioned problems, this invention provides a spring-based translational 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 stiffness change of a single translational degree of freedom caused by the configuration change during its movement is studied. This allows for the investigation of the disturbance motion law occurring within the combined arm under the joint movement of the large and small arms of the space station.

[0007] The present invention provides a spring-based translational stiffness simulation platform, comprising a platform support frame, a translational input end, a translational transmission mechanism, and a translational variable stiffness mechanism. The translational transmission mechanism includes a base plate and a guide rail assembly, the guide rail assembly including a slide rail and a slider. The slide rail is fixed to the base plate, and the slider slides linearly on the slide rail. The translational input end is fixedly connected to the top surface of the platform support frame, and the bottom surface of the platform support frame is fixedly connected to the slider. The translational variable stiffness mechanism includes a top cone seat and two variable stiffness adjustment units. The two variable stiffness adjustment units are respectively supported by the top cone on both sides of the top cone seat, and the top cone seat is fixedly installed on the side of the platform support frame. Each of the two variable stiffness 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 on the base plate. The output shaft of the drive motor is connected to the spline shaft of the ball spline through the first coupling. The flange of the ball spline is connected to the rotating shaft. The bushing is fitted on the end of the rotating shaft. The spring and bearing are respectively fitted on both ends of the bushing. The end cover is fitted on the outside of the spring and bearing. Top cone holes that mate with the top cone are formed on the end cover and the top cone seat, respectively. The platform includes a T-shaped base and a sleeve. The T-shaped base is installed on the base plate and fixedly connected to the sleeve. The sleeve is fitted on the outside of the spring. The snap-fit ​​is fixedly connected to the sleeve and snaps into the inside of the spring to control the rotation of the output shaft of the drive motor. The rotation is transmitted to the spring in sequence through the first coupling, the ball spline, the rotating shaft, and the bushing. The spring abuts against the snap-fit ​​and rotates radially to change the effective number of turns and adjust the stiffness of the translational transmission 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 base plate by means of pads.

[0011] Preferably, the translational input end is a triangular connecting frame with a connecting hole for connecting to a power source.

[0012] Preferably, the platform support frame includes an upper platform, a lower platform, and a profile frame. The profile frame is connected between the upper platform and the lower platform. The profile frame is composed of four profiles connected end to end, and the top cone seat is fixed on the profile frame.

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

[0014] Compared with the prior art, the simulation platform provided by the present invention can simulate the stiffness change of a single translational degree of freedom of the large arm during the motion process when the large and small arms of the space station are combined on the ground, and react on the small arm, thereby laying the foundation for studying the disturbance motion law that occurs in the combined arm when the large and small 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 translational stiffness simulation platform provided according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the overall structure of the variable stiffness adjustment unit provided in an embodiment of the present invention;

[0017] Figure 3 This is a cross-sectional structural schematic diagram of the variable stiffness adjustment unit provided in an embodiment of the present invention.

[0018] The reference numerals in the drawings include: upper platform 101, lower platform 102, profile frame 103, triangular connecting frame 201, connecting hole 202, base plate 301, slide rail 302, slider 303, top cone seat 401, top cone 402, drive motor 403, first coupling 404, ball spline 405, rotating shaft 406, spring 407, platform 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 pad 419. Detailed Implementation

[0019] 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.

[0020] 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.

[0021] This invention provides a spring-based translational stiffness simulation platform, which can simulate the stiffness change at the junction of the combined arms in one translational degree of freedom when the upper arm serves as the base of the lower arm.

[0022] like Figures 1-3As shown, the spring-based translational stiffness simulation platform includes a platform support frame, a translational input end, a translational transmission mechanism, and a translational stiffness variable mechanism. The translational input end is fixed on the platform support frame, which is connected to both the translational transmission mechanism and the translational stiffness variable mechanism. The translational transmission mechanism is connected to the platform support frame, and the translational input end transmits the translational motion to the platform support frame. Under the action of the translational transmission mechanism, the platform support frame undergoes a single degree of freedom translational motion. The translational stiffness variable mechanism adjusts its own stiffness by changing the effective number of spring coils and acts on the platform support frame to change the single degree of freedom translational stiffness of the translational input end, thereby achieving adjustment of the translational stiffness of the translational input end.

[0023] The platform support frame includes an upper platform 101, a lower platform 102, and a profile frame 103. The profile frame 103 is supported between the upper platform 101 and the lower platform 102, and is composed of four profiles connected end to end.

[0024] The translation input end is a triangular connecting frame 201, and a connecting hole 202 is provided on the triangular connecting frame 201 for connecting to an external power source. The power source inputs translation to the translation input end to simulate the translation of the forearm in a single horizontal direction.

[0025] The translational transmission mechanism includes a base plate 301 and a guide rail assembly. The guide rail assembly includes a slide rail 302 and a slider 303. The slide rail 302 is fixed on the base plate 301, and the slider 303 slides linearly on the slide rail 302. The triangular connecting frame 201 is fixed on the surface of the upper platform 101, and the bottom surface of the lower platform 102 is fixedly connected to the slider 303. When the triangular connecting frame 201 is input for translation, the platform support frame moves linearly along the slide rail 302.

[0026] The translational 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 the profile frame 103, which is subjected to forces in two directions. Therefore, the translational motion of the profile frame 103 is disturbed by the two variable stiffness adjustment units. By changing the output stiffness of the variable stiffness adjustment units in real time, the translational stiffness at the translational input end is controllable and time-varying.

[0027] 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 to the base plate 301 via a motor bracket 418. The output shaft of the drive motor 403 is connected to the spline shaft of the ball spline 405 via the first coupling 404. The flange of 5 is connected to the rotating shaft 406. The bushing 416 is fitted onto the end of the rotating shaft 406. The spring 407 and the bearing 415 are respectively fitted onto the two ends of the bushing 416. The end cover 417 is fitted onto the bushing 416 and is located outside the spring 407 and the bearing 415. The end cover 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 cover 417. The base 408 includes an integral part. The T-shaped base 409 and sleeve 410 are structurally or separately constructed. The T-shaped base 409 is fixedly installed on the base plate 301 by a pad 419, which supports and fixes the sleeve 410. The pad 419 serves to raise the platform 408. 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 structurally or separately constructed. The snap cone block 413 is fixed on the outside of the sleeve 410 by a fastening bolt 414. The snap cone 412 passes through the sleeve 410 and snaps into the inside of the spring 407. The output shaft of the control drive motor 403 rotates and is transmitted to the spring 407 in sequence through the first coupling 404, ball spline 405, rotating shaft 406, and bushing 416. The spring 407 abuts against the snap cone 412 and rotates radially, thereby changing the effective number of turns of the spring 407 and realizing the time-varying stiffness output of the end cover 417 to the top cone seat 401.

[0028] 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.

[0029] 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.

[0030] In this embodiment of the invention, translational motion is transmitted through a translational input end. The platform support frame and translational transmission mechanism then transfer the translational motion to a translational variable stiffness mechanism. Due to interference from the translational variable stiffness mechanism, the stiffness of the translational input end in its translational degrees of freedom is adjusted in real time by changing the stiffness of the mechanism. In this way, the real-time changing translational stiffness during boom movement is simulated.

[0031] 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.

[0032] 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 translational stiffness simulation platform, characterized in that, This includes a platform support frame, a translational input end, a translational transmission mechanism, and a translational variable stiffness mechanism; among which, The translational transmission mechanism includes a base plate and a guide rail assembly. The guide rail assembly includes a slide rail and a slider. The slide rail is fixed on the base plate, and the slider slides linearly on the slide rail. The translational input end is fixedly connected to the top surface of the platform support frame, and the bottom surface of the platform support frame is fixedly connected to the slider. The translational variable stiffness mechanism includes a top cone seat and two variable stiffness adjustment units. The two adjustment units are respectively supported on both sides of the top cone seat via the top cone. The top cone seat is fixedly installed on the side of the platform support frame. Each of the two variable stiffness 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 base plate. 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 the bushing. At both ends, the end caps are fitted onto the outside of the spring and the bearing, and top cone holes that mate with the top cone are formed on the end caps and the top cone seat, respectively; the base includes a T-shaped base and a sleeve, the T-shaped base is mounted on the base plate 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 output shaft of the drive motor to rotate, and transmitting the rotation sequentially through the first coupling, the ball spline, the rotating shaft, and the bushing to the spring, the spring abutting against the snap-fit ​​and rotating radially, changing the effective number of turns, and adjusting the stiffness of the translational transmission mechanism.

2. The spring-based translational 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 translational 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 translational stiffness simulation platform according to claim 1, characterized in that, The T-shaped base is fixedly installed on the base plate by pads.

5. The spring-based translational stiffness simulation platform according to claim 1, characterized in that, The translational input end is a triangular connecting frame with a connection hole for connecting to a power source.

6. The spring-based translational stiffness simulation platform according to claim 5, characterized in that, The platform support frame includes an upper platform, a lower platform, and a profile frame. The profile frame is connected between the upper platform and the lower platform. The profile frame is composed of four profiles connected end to end. The top cone seat is fixed on the profile frame.

7. The spring-based translational stiffness simulation platform according to claim 1, characterized in that, The drive motor is fixedly mounted on the base plate via a motor bracket.

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