Rotational stiffness simulation platform based on flexible frame

Abstract

The present application relates to the technical field of space mechanics simulation, and particularly relates to a rotating stiffness simulation platform based on a flexible framework, which comprises a support frame, a rotating input end, a rotating transmission mechanism and a rotating variable stiffness mechanism fixed on the support frame respectively, the rotating transmission mechanism is connected with the rotating input end and the rotating variable stiffness mechanism respectively, the rotation input by the rotating input end is transmitted to the rotating transmission mechanism, and the rotating variable stiffness mechanism adjusts the stiffness of the rotating transmission mechanism by changing the position of the support point, so as to realize the adjustment of the rotating stiffness of the rotating input end. The simulation platform provided by the present application can simulate the real-time change of the rotating stiffness of the large arm in the movement process when the space station is combined with the large arm and the small arm on the ground, and the change can act on the small arm, so as to lay a foundation for studying the disturbance motion law of the combined arm under the joint movement of the space station, the large arm and the small arm.

Description

Technical Field

[0001] This invention relates to the field of space mechanics simulation technology, specifically providing a rotational stiffness simulation platform based on a flexible frame. 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 rotational stiffness simulation platform based on a flexible frame, which 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 law occurring within the combined arm under the joint movement of the large and small arms of the space station.

[0007] The rotational stiffness simulation platform based on a flexible frame provided by the present invention includes a support frame and a rotational input end, a rotational transmission mechanism, and a rotational stiffness variable mechanism respectively fixed on the support frame; wherein, the rotational transmission mechanism includes a first coupling and a flexible frame, the flexible frame includes a frame body, a connecting shaft is formed on the surface of the frame body, and three pairs of flexible plates distributed at 120 degrees are formed on the side of the frame body, and the connecting shaft is connected to the rotational input end through the first coupling. The rotary variable stiffness mechanism includes three roller-slider assemblies, a cage, a stiffness-adjusting motor, a second coupling, a pinion gear with a shaft, and a large gear with a shaft. The cage is fixed to a support frame via a support column and is located below the flexible frame. Three elongated sliding holes are formed on the cage at 120-degree intervals, and a boss is formed on the inner wall of each elongated sliding hole. Each of the three roller-slider assemblies includes a pressure block, a roller, an engaging slider, a rack slider, and a linear guide. The pressure block is fixed to the engaging slider, and the roller is rotatably connected to the pressure block and located between two opposing flexible plates. An inclined groove is formed on the bottom surface of the engaging slider, and a sliding contact point with the boss is formed on the side surface of the engaging slider. The rack and pinion slider has a straight slide groove, and a slanted protrusion on the top surface that slides with the slanted slide groove. A straight rack is formed on the side of the rack and pinion slider. The guide component of the linear guide is fixed on the support frame, and the rack and pinion slider is fixed on the moving part of the linear guide. The stiffness-adjusting motor is fixed on the support frame, and the output shaft of the stiffness-adjusting motor is connected to the pinion with a shaft through a second coupling. The large gear with a shaft is rotatably connected to the support frame, and the large gear with a shaft meshes with the straight rack and the pinion with a shaft respectively. The stiffness-adjusting motor drives the meshing slider to slide linearly along the elongated sliding hole of the cage, changing the position of the support point where the roller contacts the two opposing flexible plates, and adjusting the stiffness of the rotation transmission mechanism.

[0008] Preferably, the support frame includes an upper support plate, a lower support plate, and a C-shaped connecting plate. The C-shaped connecting plate is connected between the upper support plate and the lower support plate. The upper support plate has a hollow structure. The retainer is fixed to the top surface of the lower support plate by a column. The guide of the linear guide is fixed to the top surface of the lower support plate. The tension-adjusting motor is fixed to the bottom surface of the lower support plate. The large gear with a shaft is rotatably connected to the lower support plate.

[0009] Preferably, 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 formed ridges, which are fixed to the top surface of the upper support plate by screws. A rolling bearing is installed at the bottom of the U-shape of the U-shaped frame. The other end of the first coupling is fixedly connected to a rotating shaft, which is fixedly connected to the triangular connecting frame and rotates with the U-shaped frame through the rolling bearing.

[0010] Compared with the prior art, the simulation platform provided by the present invention can simulate the change in rotational stiffness 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

[0011] Figure 1 This is a schematic diagram of the rotational stiffness simulation platform based on a flexible frame provided according to an embodiment of the present invention;

[0012] Figure 2 This is a partial structural schematic diagram of a rotational stiffness simulation platform based on a flexible frame provided according to an embodiment of the present invention;

[0013] Figure 3 This is a schematic diagram of the flexible framework provided in an embodiment of the present invention;

[0014] Figure 4 This is a schematic diagram of the structure of the roller slider assembly provided in an embodiment of the present invention;

[0015] Figure 5 This is a schematic diagram of the cage structure provided according to an embodiment of the present invention;

[0016] Figure 6 This is a schematic diagram of the cooperation between the rotation transmission mechanism and the rotational stiffness variable mechanism provided in an embodiment of the present invention from a first-view perspective.

[0017] Figure 7 This is a schematic diagram of the cooperation between the rotation transmission mechanism and the rotational stiffness variable mechanism provided in an embodiment of the present invention from a second perspective.

[0018] The reference numerals in the accompanying drawings include: triangular connecting frame 101, U-shaped frame 102, connecting hole 103, edge 104, first coupling 202, flexible frame 203, frame body 204, connecting shaft 205, flexible sheet 206, retainer 208, adjustable motor 209, second coupling 210, pinion with shaft 211, gear with shaft 212, elongated sliding hole 214, boss 215, pressure block 216, roller 217, meshing slider 218, rack and pinion slider 219, linear guide rail 220, inclined slide groove 221, straight slide groove 222, inclined protrusion 223, straight rack 224, support column 225, upper support plate 301, lower support plate 302, and C-shaped connecting plate 303. 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 rotational stiffness simulation platform based on a flexible frame. This platform 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.

[0022] like Figures 1-7 As shown, the rotational stiffness simulation platform based on a flexible frame includes a support frame, a rotational input end, a rotational transmission mechanism, and a rotational stiffness variable mechanism. The rotational input end, the rotational transmission mechanism, and the rotational stiffness variable mechanism are respectively fixed on the support frame. The rotational transmission mechanism is connected to the rotational input end and the rotational stiffness variable mechanism respectively. The rotation input from the rotational input end is transmitted to the rotational transmission mechanism. The rotational stiffness variable mechanism adjusts the stiffness of the rotational transmission mechanism by changing the position of the support point, thereby realizing the adjustment of the rotational stiffness of the rotational input end.

[0023] The support frame includes an upper support plate 301, a lower support plate 302, and a C-shaped connecting plate 303, with the C-shaped connecting plate 303 fixedly connected between the upper support plate 301 and the lower support plate 302.

[0024] The rotation input end includes a triangular connecting frame 101 and a U-shaped frame 102. The triangular connecting frame 101 can rotate relative to the U-shaped frame 102. A connecting hole 103 is provided on the triangular connecting frame 101 for connecting to an external power source. The power source inputs rotation to the triangular connecting frame 101 to simulate the horizontal rotation of the forearm. The two ends of the U-shaped frame 102 have outwardly formed flanges 104, which are fixed to the upper support plate 301 by screws. A rolling bearing is installed at the U-shaped bottom of the U-shaped frame 102. The upper support plate 301 is a hollow structure, and the upper support plate 301 and the U-shaped frame 102 form a space to accommodate the rotation transmission mechanism.

[0025] The rotation transmission mechanism includes a first coupling 202 and a flexible frame 203. The flexible frame 203 includes a frame body 204. A connecting shaft 205 is formed on the surface of the frame body 204. Three pairs of flexible plates 206 distributed at 120 degrees are formed on the side of the frame body 204. The connecting shaft 205 is fixedly connected to one end of the first coupling 202. A rotating shaft is fixedly connected to the other end of the first coupling 202. The rotating shaft is fixedly connected to the triangular connecting frame 101 and rotates with the U-shaped frame 102 through a rolling bearing. The rotation of the triangular connecting frame 101 is transmitted to the flexible frame 203 through the first coupling 202.

[0026] The rotational stiffness-changing mechanism includes a cage 208, a stiffness-adjusting motor 209, a second coupling 210, a pinion gear 211 with a shaft, a large gear 212 with a shaft, and three roller slider assemblies. The lower support plate 302 is fixed below the upper support plate 301 via a C-shaped connecting plate 303. The cage 208 is fixed to the lower support plate 302 via a support column 225 and is located below the flexible frame 203. Three elongated sliding holes 214 are formed on the cage 208 at 120-degree intervals, and a boss 215 is formed on the inner wall of each elongated sliding hole 214. The three roller slider assemblies... Each component includes a pressure block 216, a roller 217, an engaging slider 218, a rack slider 219, and a linear guide 220. The pressure block 216 has a stepped structure, with its lower surface fixedly connected to the engaging slider 218 and its upper surface rotatably connected to the roller 217. The roller 217 is located between two opposing flexible plates 206 and is in contact with the flexible plates 206. An inclined groove 221 is formed on the bottom surface of the engaging slider 218, and a straight groove 222 is formed on the side surface of the engaging slider 218 to slide with the boss 215. A groove is provided on the top surface of the rack slider 219 to slide with the inclined groove 221. The oblique protrusion 223 of the moving fit forms a straight rack 224 on the side of the rack slider 219; the bearing of the linear guide 220 is fixed on the lower support plate 302, the rack slider 219 is fixed on the moving part of the linear guide 220, and the rack slider 219 slides linearly along the linear guide 220; the pinion 211 with shaft has a rotating shaft on both sides of the axial direction, and a bearing hole is opened on the cage 208 corresponding to the position of the pinion 211 with shaft, and a bearing is installed in the bearing hole; the adjustable motor 209 is fixed on the bottom surface of the lower support plate 302, and the output shaft of the adjustable motor 209 is... The pinion 211 is connected to the shaft on one side of the pinion 211 via the second coupling 210. The shaft on the other side of the pinion 211 is installed in the bearing of the cage 208, which enables the pinion 211 to rotate relative to the cage 208. The large gear 212 has a short shaft on one axial side, and a bearing is installed on the lower support plate 302. The short shaft of the large gear 212 is installed in the bearing of the lower support plate 302, which enables the large gear 212 to rotate with the lower support plate 302. The large gear 212 meshes with the spur rack 224 and the pinion 211.

[0027] The stiffness of the rotation transmission mechanism is adjusted by driving the meshing slider 218 to slide linearly along the elongated sliding hole 214 of the retainer 208 by the stiffening motor 209, thereby changing the position of the support point where the roller 217 contacts the two opposing flexible plates 206.

[0028] The rotation at the input end is converted into rotation of the flexible frame 203 by a rotation transmission mechanism. The flexible sheet 206 of the flexible frame 203 contacts the roller 217 to form a support point, thus disturbing the rotation of the flexible frame 203. By changing the position of the support point in real time, the rotational stiffness of the flexible frame 203 is effectively changed, making the rotational stiffness of the input end controllable and time-varying.

[0029] The method for changing the support point position in real time is as follows: the adjusting motor 209 drives the pinion 211 with shaft to rotate, and the pinion 211 drives the large gear 212 with shaft to rotate, causing the rack slider 219 to slide on the linear guide rail 220. Since the meshing slider 218 cooperates with the rack slider 219 and the cage 208 respectively, the motion of the meshing slider 218 is converted into linear motion along the elongated sliding hole 214, thereby changing the position of the support point between the roller 217 and the flexible sheet 206.

[0030] This invention transmits rotation through a rotation input end. A rotation transmission mechanism transfers and converts the rotational force to a rotational variable stiffness mechanism. Due to interference from the rotational variable stiffness mechanism, the stiffness of the rotational transmission mechanism is adjusted in real time by changing the stiffness of the rotational variable stiffness mechanism. Then, through stiffness conversion, the stiffness at the rotation input end can be controlled. In this way, the real-time changing rotational stiffness of the boom during 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 rotational stiffness simulation platform based on a flexible frame, characterized in that, It includes a support frame and a rotation input end, a rotation transmission mechanism, and a rotational stiffness adjustment mechanism, all fixed to the support frame; wherein, The rotation transmission mechanism includes a first coupling and a flexible frame. The flexible frame includes a frame body, a connecting shaft is formed on the surface of the frame body, and three pairs of flexible plates distributed at 120 degrees are formed on the side of the frame body. The connecting shaft is connected to the rotation input end through one end of the first coupling. The rotational variable stiffness mechanism includes three roller-slider assemblies, a cage, a stiffness-adjusting motor, a second coupling, a pinion gear with a shaft, and a large gear with a shaft; wherein... The retainer is fixed to the support frame by a column and is located below the flexible frame. Three elongated sliding holes are formed on the retainer at 120 degrees, and a boss is formed on the inner wall of each elongated sliding hole. Each of the three roller-slider assemblies includes a pressure block, a roller, an engaging slider, a rack slider, and a linear guide. The pressure block is fixed to the engaging slider. The roller is rotatably connected to the pressure block and located between two opposing flexible plates. An inclined groove is formed on the bottom surface of the engaging slider, and a straight groove is formed on the side surface of the engaging slider to slide with the boss. An inclined protrusion is provided on the top surface of the rack slider to slide with the inclined groove, and a straight rack is formed on the side surface of the rack slider. The guide member of the linear guide is fixed to the support frame, and the rack slider is fixed to the moving part of the linear guide. The adjustable motor is fixed on the support frame. The output shaft of the adjustable motor is connected to the pinion with shaft through the second coupling. The large gear with shaft is rotatably connected to the support frame. The large gear with shaft meshes with the spur rack and the pinion with shaft respectively. The stiffness of the rotation transmission mechanism is adjusted by driving the meshing slider to slide linearly along the elongated sliding hole of the cage by the stiffening motor, thereby changing the position of the support point where the roller contacts the two opposing flexible plates.

2. The rotational stiffness simulation platform based on a flexible frame according to claim 1, characterized in that, The support frame includes an upper support plate, a lower support plate, and a C-shaped connecting plate. The C-shaped connecting plate is connected between the upper support plate and the lower support plate. The upper support plate has a hollow structure. The retainer is fixed to the top surface of the lower support plate by the support column. The guide member of the linear guide rail is fixed to the top surface of the lower support plate. The stiffening motor is fixed to the bottom surface of the lower support plate. The large gear with shaft is rotatably connected to the lower support plate.

3. The rotational stiffness simulation platform based on a flexible frame according to claim 2, 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 formed ridges, which are fixed to the top surface of the upper support plate by screws. A rolling bearing is installed at the U-shaped bottom of the U-shaped frame. The other end of the first coupling is fixedly connected to a rotating shaft, which is fixedly connected to the triangular connecting frame and rotates with the U-shaped frame through the rolling bearing.

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