Rigidity improving mechanism for robot and working method

Abstract

The invention discloses a rigidity improving mechanism for a robot and a working method, relates to the technical field of robots, solves the problem of flutter of an industrial robot structure in the prior art, and has the beneficial effect of inhibiting flutter of the robot structure. Comprising a base support arranged at a first joint of the robot, a damper component supported by the base support, a two-axis joint damping disc arranged at a second joint of the robot, a pulley block arranged at the two-axis joint damping disc, a large arm support arranged at a second connecting rod large arm of the robot, and an auxiliary arm support arranged at a parallel connecting rod auxiliary arm of the robot. The damping rope is connected with the large arm support and the auxiliary arm support, then is wound to the damper component and continues to pass through the tensioning device to be wound around the pulley block at the two-shaft joint damping disc, the torque direction of the damping rope is changed through the pulley block, and the damping rope provides damping torque for the robot.

Description

Technical Field

[0001] The invention relates to the technical field of robots, and in particular to a rigidity enhancement mechanism and a working method for a robot. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Industrial robots are widely used in many fields due to their large accessible space, high dexterity, compact size and versatility. They have promoted the transformation of traditional industries from traditional labor-intensive to technology-intensive industries, and improved the overall level and competitiveness of high-end manufacturing industries. However, industrial robots are typical open-chain multi-rod series structures. Affected by the coupling of transmission mechanisms, joint deformation, friction, environment and other factors, it is very easy to induce robot resonance and produce medium and low frequency vibrations when processing high-strength workpieces. In addition, the stiffness of the robot has the characteristics of nonlinear distribution in the entire workspace. The external forces applied to the robot during the processing process will cause irregular deviations, thereby affecting the surface quality and processing accuracy of the workpiece. Studies have shown that the robot positioning error caused by robot geometry and stiffness factors accounts for more than 90% of the total positioning error, which seriously limits the application of industrial robots in high-precision processing.

[0004] At present, the commonly used method is to optimize the process parameters offline for machining chatter. The universality of working conditions is poor, and the suppression method is limited by the weak stiffness characteristics of the robot itself. It is unable to accurately compensate for the elastic deformation movement of the joints while the robot arm is rigidly rotating. There are still problems such as multi-variable input, strong nonlinearity, and severe coupling of dynamic characteristics.

[0005] The main source of robot structural vibration is the radial and axial clearances that cannot be adjusted during the joint driving process, which shows the flexibility of the joints and the weak stiffness of the end processing trajectory. Existing methods for industrial robot vibration suppression mainly attach vibration suppression devices to the end effector, and use semi-active and passive vibration suppression methods to introduce the processing vibration energy into the additional transposition for dissipation, thereby improving the dynamic stiffness of the robot processing trajectory. However, the robot processing stiffness is highly related to the posture. During the part processing process, the dynamic stiffness of the end has spatial time-varying characteristics, and the end vibration suppression device will introduce additional rotational inertia, which affects the robot's environmental adaptability and dynamic response, causing redundant waste of joint output torque, and has certain applicability limitations. Summary of the invention

[0006] In view of the deficiencies in the prior art, an object of the present invention is to provide a stiffness enhancement mechanism for a robot, which can achieve flutter energy dissipation during robot processing through a damper component and optimize the system structural stiffness.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions: A stiffness enhancement mechanism for a robot comprises a base bracket arranged at a first joint of the robot, the base bracket supports a damper component, a two-axis joint damping disk is arranged at a second joint of the robot, a pulley block is arranged at the two-axis joint damping disk, a boom bracket is arranged at the second connecting rod boom of the robot, a jib bracket is arranged at the parallel connecting rod jib of the robot, a damping cable is connected to the boom bracket and the jib bracket and then goes around the damper component, continues to pass through a tensioning device and bypasses the pulley block at the two-axis joint damping disk, the torque direction of the damping cable is changed by the pulley block, and the damping cable provides a damping torque to the robot.

[0008] A stiffness enhancement mechanism for a robot as described above also includes a first pulley and a second pulley, the first pulley is arranged at the hinge between the parallel link auxiliary arm and the second link main arm, the second pulley is arranged below the two-axis joint damping disk, and the damping cable is arranged to bypass the first pulley and the second pulley to change the direction of the damping cable through the first pulley and the second pulley.

[0009] As described above, a stiffness improvement mechanism for a robot, the damping cable comprises two sections, the first section of the damping cable passes through the boom support, the auxiliary arm support and the first pulley setting in sequence, the second section of the damping cable passes through the pulley group, the second pulley, the tensioning device and the damper component in sequence, the first section of the damping rope is connected to the second section of the damper through a tension sensor to form a closed cable assembly.

[0010] A stiffness improvement mechanism for a robot as described above, the two-axis joint damping plate includes a pulley block base, the pulley block base is coaxially connected to the second joint, the pulley block base supports the pulley block, the pulley block includes a third pulley and a fourth pulley, a plurality of third pulleys are provided, and at least two fourth pulleys are provided. The plurality of third pulleys are arranged along the circumference of the pulley block base, the fourth pulley is located on the inner side of the third pulley, and a protruding arrangement is provided on one side of the pulley block base. A redirecting pulley is provided at the protruding portion of the pulley block base, and the damping cable passes through part of the third pulley, the fourth pulley, another third pulley and the redirecting pulley in sequence, so that the damping cable is located at a section between the redirecting pulley and the boom bracket and has the same direction as the second connecting rod boom.

[0011] As described above, a stiffness improvement mechanism for a robot is further provided with a stop component at the protrusion of the pulley block base, and the stop component connects the pulley shaft of the redirecting pulley and the protrusion of the pulley block base, so that a distance is set between the stop component and the redirecting pulley to limit the damping cable.

[0012] A rigidity improvement mechanism for a robot as described above, wherein the boom bracket is provided with at least two, the boom bracket is fixed to the circumferential direction of the second connecting rod boom, the eye bolt is installed on the side of the boom bracket, the damping cable is passed through the eye bolt of the boom bracket, and the eye bolt is installed on the boom bracket through the boom eye fixing piece; The jib bracket is provided with at least one, the jib bracket and the boom bracket are arranged alternately, the jib bracket is fixed to the circumferential direction of the parallel connecting rod jib, the eye bolt is installed on the side of the jib bracket, the damping cable passes through the eye bolt at the jib bracket, and the eye bolt is installed on the jib bracket through the jib eye fixing piece; The structures of the boom lifting eye fixing piece and the jib lifting eye fixing piece are the same. Both of them include a convex cavity, a second nut is arranged in the convex cavity, and a third nut is arranged outside the convex cavity. The lifting eye bolt passes through the third nut and the second nut in sequence.

[0013] As described above, a stiffness enhancement mechanism for a robot is provided with an adaptive clamping claw on the side of the boom bracket, and the adaptive clamping claw includes an adjusting bolt, which passes through a welding nut and the side of the boom bracket, and the welding nut is fixed to the side of the boom bracket. The end of the adjusting bolt is connected to a fastening hinge, and the fastening hinge is hingedly connected to the clamping claw lobe, and the clamping claw lobe can rotate along the fastening hinge to adapt to the second connecting rod boom.

[0014] As described above, a stiffness improvement mechanism for a robot, the damper component includes two sliding damping components, a tensioning pulley is arranged between the two sliding damping components, the damping cable is arranged around the tensioning pulley, the sliding damping component includes two dampers arranged oppositely, the telescopic ends of the two dampers are connected to the damper center block, the damper center rod is arranged through the damper center block, the damper center rod passes through one end of the damper center block and is connected to the base bracket, the other end of the damper center rod passes through the damper limit block, the damper center rod is located on both sides of the damper center block and is respectively covered with tension springs, and the fixed end of the damper is connected to the base bracket and the damper limit block through a connecting rod.

[0015] A stiffness enhancement mechanism for a robot as described above, wherein the tensioning device includes a tensioning bracket, the tensioning bracket is mounted on the base bracket, the position of the tensioning bracket relative to the base bracket is adjustable, the tensioning bracket supports a tensioning adjustment component and a tensioning clamping component, the tensioning adjustment component includes a moving part, the moving part is slidably mounted on the tensioning bracket, the moving part is connected to the cylindrical clamping shaft, a fifth pulley is arranged at one end of the cylindrical clamping shaft away from the moving part, the damping cable is arranged to bypass the fifth pulley to adjust the tension of the damping cable through the moving part, and a stop part is arranged on one side of the fifth pulley.

[0016] As described above, a stiffness enhancement mechanism for a robot, the tensioning clamping assembly clamps the cylindrical clamping shaft and is capable of locking the cylindrical clamping shaft, the fifth pulley is arranged below the damper component, and the cylindrical clamping shaft is arranged inclined upward relative to the bottom of the base bracket.

[0017] As described above, a stiffness enhancement mechanism for a robot, the base bracket includes a bottom frame, the bottom frame supports a vertical frame, the vertical frame supports a mounting plate, the mounting plate is provided with multiple layers of mounting holes, the mounting holes of two adjacent layers of mounting holes are staggered, and the damper component is installed on the mounting plate through the mounting holes.

[0018] In a second aspect, the present invention further provides a working method for a stiffness enhancement mechanism of a robot, comprising the following contents: A base bracket is arranged at the first joint of the robot, the base bracket supports the damper component, a two-axis joint damping disk is arranged at the second joint, a pulley block is arranged at the two-axis joint damping disk, a big arm bracket is arranged at the second connecting rod big arm, and a jib bracket is arranged at the parallel connecting rod jib; The damping cable is connected to the boom support and the auxiliary arm support and then goes around the damper component, and then passes through the tensioning device and around the pulley block at the two-axis joint damping plate; The robot is in a zero-position posture, the damper component provides a damping internal force for the damping cable, and the tensioning device abuts against the damping cable and deforms it to provide an initial tensioning force according to actual application requirements; During the working process of the first arm, the second link arm, the parallel link jib and the third arm of the robot, a damping torque is introduced to the second joint, the second link arm and the parallel link jib through the damping cable to realize the dissipation of the flutter energy of the joint structure.

[0019] The beneficial effects of the present invention are as follows: 1) In order to solve the problems of weak structural rigidity and severe dynamic coupling of industrial robots, the present invention connects the second link arm and the parallel link auxiliary arm through damping cables, and provides damping through a damper component. In this way, the damping torque is introduced to the second joint, the third joint, the second link arm and the parallel link auxiliary arm of the robot through the damping cables, so as to achieve effective dissipation of the flutter energy of the joint structure and improve the processing stability and precision of the robot. At the same time, the stiffness improvement mechanism is designed to fit the structure of the industrial robot without interfering with its original degrees of freedom and workspace, ensuring that the robot meets the requirements of complex working tasks and has high adaptability and compatibility. In this way, the processing precision of the industrial robot is improved without sacrificing the environmental adaptability and dynamic response characteristics of the robot.

[0020] 2) The present invention can adjust the tension on the damping cable to an appropriate range according to the inherent mode of the robot joint, ensure the modal matching state between the robot and the stiffness improvement mechanism, thereby inducing the vibration generated by the joint during the robot processing to the damping cable, thereby reducing the modal frequency of the robot joint. At the same time, the sliding damping component can automatically adjust the motion range of the damping cable according to the motion state of the robot arm during the processing, and effectively apply a stable damping force to the damping cable, so that the robot with the stiffness improvement mechanism can maintain the continuity and stability of the damping internal force under various processing conditions.

[0021] 3) The pulley block structure of the present invention is reasonably arranged. The pulley block includes a third pulley and a fourth pulley. The third pulley is located outside the fourth pulley. In this way, the damping cable can pass around part of the third pulley and the fourth pulley and then pass around another third pulley. The damping cable can be redirected by setting a redirection pulley.

[0022] 4) The structures of the boom support and the jib support in the present invention are reasonably arranged, and cooperate with the second connecting rod boom and the parallel connecting rod jib of the robot respectively to ensure stable arrangement. An adaptive clamping claw is arranged at the boom support to effectively fit with the second connecting rod boom. The boom support and the jib support respectively support the corresponding eye bolts through the boom lifting ring fixing parts and the jib lifting ring fixing parts to ensure the stable arrangement of the eye bolts and prevent the eye bolts from moving due to the traction force of the damping cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 An assembly diagram of a robot with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0025] Figure 2 An exploded view of a two-axis joint damping disk of a robot with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0026] Figure 3 The present invention is a schematic diagram of the passage of the damping cable in a robot pulley block with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0027] Figure 4 An exploded view of a robot arm support with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0028] Figure 5 An exploded view of a robot auxiliary arm bracket with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0029] Figure 6 An exploded view of a robot base bracket with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0030] Figure 7 An exploded view of a robot tensioning device with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0031] Figure 8 An exploded view of a robot tensioning motion device with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0032] Fig. 9 An exploded view of a robot damper assembly with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0033] Fig.10 An exploded view of a robot sliding damping device with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0034] Fig.11 The exploded view is of a robot closed cable assembly with a stiffness enhancement mechanism according to one or more embodiments of the present invention.

[0035] Fig.12 An assembly diagram of a robot with a stiffness enhancement mechanism according to one or more embodiments of the present invention when the robot is in a zero-point posture.

[0036] Fig.13 An assembly diagram of a robot with a stiffness enhancement mechanism according to one or more embodiments of the present invention when the robot is located at an extreme position.

[0037] In the figure: the distances or sizes between parts are exaggerated to show the positions of various parts, and the schematic diagram is for reference only.

[0038] Among them: 1. Two-axis joint damping plate; 2. Big arm bracket; 3. Jib bracket; 4. Base bracket; 5. Tensioning device; 6. Damper component; 7. Closed cable assembly; 8. First steering pulley bracket; 9. Second steering pulley bracket; 10. Fixed bracket; 11. Base; 12. First arm; 13. Second joint; 14. Second connecting rod big arm; 15. Parallel connecting rod jib; 16. Third joint; 17. Fourth connecting rod; 18. End effector; 101, adapter plate; 102, pulley block base; 103, pulley block; 104, pulley block top cover; 105, redirecting pulley; 106, baffle; 107, pin; 108, retaining ring; 109, split pin; 110, pulley fastening nut; 111, third pulley; 112, fourth pulley; 201, boom support bottom plate; 202, boom support U-shaped plate; 203, first bolt; 204, first nut; 205, boom rubber anti-skid pad; 206, adjustment bolt; 207, welding nut; 208, fastening hinge point; 209, tightening claw leaf; 210, boom lifting ring fixing piece; 211, second bolt; 212, second nut; 213, third nut; 214, lifting eye bolt; 301, Jib bracket U-shaped plate; 302, Jib rubber anti-skid pad; 303, Jib lifting ring fixing piece; 401, first support frame; 402, second support frame; 403, third support frame; 404, third bolt; 405, boat-shaped nut; 406, right angle bracket; 407, acute angle bracket; 408, obtuse angle bracket; 409, mounting plate; 501, fourth support frame; 502, fifth support frame; 503, clamping plate; 504, deep groove ball bearing; 505, gear shaft; 506, rotating wheel; 507, rack; 508, fourth bolt; 509, cylindrical clamping shaft; 510, first clamping block; 511, second clamping block; 512, locking bolt; 601, tension pulley; 602, viscous damper; 603, damper center block; 604, pin shaft; 605, damper center rod; 606, tension spring; 607, damper base; 608, damper limit block; 609, connecting rod; 610, connecting pad; 701, first tension sensor; 702, second tension sensor; 703, damping cable; 7031, first section of damping cable; 7032, second section of damping cable; 801, first pulley; 901, second pulley. DETAILED DESCRIPTION

[0039] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof; As introduced in the background technology, there is a problem of low-frequency vibration in the movement process of the robot in the prior art. In order to solve the above technical problem, the present invention proposes a stiffness improvement mechanism for the robot.

[0041] Embodiment 1 In a typical embodiment of the present invention, reference is made to Figure 1 As shown, a stiffness enhancement mechanism for a robot, the robot includes a base 11, the base 11 rotatably supports a first arm 12 through a first joint, the first arm 12 is connected to a second connecting rod arm 14 through a second joint 13, a parallel connecting rod auxiliary arm 15 is arranged on the side of the second connecting rod arm 14, the second connecting rod arm 14 and the parallel connecting rod auxiliary arm 15 are connected to the third arm through a third joint 16, the third arm is connected to a fourth connecting rod 17, an end effector 18 is arranged at the end of the robot, and the stiffness enhancement mechanism includes a base bracket 4 arranged at the first joint of the robot, the base bracket 4 supports a damper component 6, A two-axis joint damping disk 1 is arranged at the second joint 13 of the robot, a pulley group 103 is arranged at the two-axis joint damping disk 1, a boom support 2 is arranged at the second connecting rod boom 14 of the robot, and a jib support 3 is arranged at the parallel connecting rod jib 15 of the robot (the parallel connecting rod jib 15 is located on one side of the second connecting rod boom 14). The damping cable 703 is connected to the boom support 2 and the jib support 3 and then goes around the damper component 6, continues to pass through the tensioning device 5 and bypasses the pulley group at the two-axis joint damping disk 1, and changes the torque direction of the damping cable through the pulley group, so that the damping cable 703 provides a damping torque to the robot.

[0042] In this embodiment, the two-axis joint damping plate 1 is fixed to the preset threaded hole at the second joint 13 of the robot by bolts, and coincides with the central axis of the second joint 13. A plurality of boom brackets 2 are evenly arranged on the second connecting rod boom 14 of the robot as required, and the number of boom brackets 2 is greater than or equal to two. At least one auxiliary arm bracket 3 is evenly arranged at the parallel connecting rod auxiliary arm 15 of the robot as required, and the boom bracket 2 and the auxiliary arm bracket 3 are staggered, that is, the first auxiliary arm bracket 3 is higher than the first boom bracket 2, and the number of boom brackets 2 is one more than the number of auxiliary arm brackets 3. The damping cable 703 passes through the pulley block 103, the redirecting pulley 105, the boom bracket 2, and the auxiliary arm bracket 3 in the two-axis joint damping plate 1 in turn to form a closed loop, thereby forming a closed cable assembly 7; In addition, the tensioning device 5 is used to change the extension length of the damping cable 703, thereby adjusting the initial preload force of the closed cable assembly 7; the damper component 6 is used to compensate for the dynamic change of the position of the damping cable 703 during the movement of the robot to prevent the cable from breaking due to excessive extension. At the same time, the damper component 6 can provide a continuous and stable damping internal force for the closed cable assembly 7 during the change of the extension length.

[0043] It should be noted that, considering that when the damping cable 703 passes through the two-axis joint damping disk 1 and the boom bracket 2, there is easy interference with the robot structural parts, in order to adjust the passage path of the damping cable 703, a first steering pulley bracket 8 is set at the upper hinge position of the robot parallel connecting rod auxiliary arm 15, and a first pulley 801 is set at the first steering pulley bracket 8, and a second steering pulley bracket 9 is set below the second joint 13 of the robot. The second steering pulley bracket 9 is set with a second pulley 901, and the second pulley 901 is fixed to the second steering pulley bracket 9 on both sides by pulley fastening nuts.

[0044] refer to Figure 2 , Figure 3 and Fig.12 As shown, the two-axis joint damping plate 1 is provided with an adapter plate 101, a pulley block base 102, a pulley block 103, and a pulley block top cover 104 in sequence along the axis direction of the second joint of the robot. The adapter plate 101 is provided with bolt through holes according to the arrangement of threaded holes on the second joint of the robot, and is fixed to the second joint 13 of the robot by bolts. After installation, the central axis of the adapter plate 101 is ensured to coincide with the central axis of the second joint of the robot. The pulley block base 102 is fixed to the adapter plate 101 by bolts, and a plurality of pulley mounting holes (a third pulley mounting hole and a fourth pulley mounting hole) are provided on the pulley block base 102 for fixing and mounting the pulley block 103.

[0045] Specifically, the third pulley mounting holes are evenly opened along the circumference of the pulley block base 102, and there are eight third pulley mounting holes. The eight axially distributed pulley mounting holes all need to install the third pulley 111. The fourth pulley mounting hole is opened near the axis of the pulley block base 102. The number of the fourth pulley mounting holes is four. The centers of the four pulley mounting holes are distributed in a rectangular shape. The four pulley mounting holes distributed in the rectangular shape only need to install two fourth pulleys 112 in the diagonal direction as required. In this way, ten pulleys are arranged at the pulley block base 102 to form the pulley block 103. After the damping cable 703 passes through some of the circumferential third pulleys (such as four third pulleys), it passes through two fourth pulleys 112 and then continues to pass through the remaining third pulleys 111. In this way, after the damping cable 703 passes through the pulley blocks 103 arranged in multiple pulley mounting holes in series, the internal force in the damping cable 703 can be converted into a joint damping torque, thereby suppressing the torque fluctuation caused by nonlinear friction and clearance of the joint.

[0046] The damping cable 703 passes around the fourth pulley 112 at the first location and then passes around the fourth pulley 112 at the second location in the reverse direction.

[0047] In this embodiment, the pulley block top cover 104 is provided with fixing holes according to the positions of the third pulley mounting hole and the fourth pulley mounting hole on the pulley block base 102, and is fixed to the unfixed end of the pulley block 103 through a pulley fastening nut 110. After the adapter plate 101, the pulley block base 102 and the pulley block top cover 104 are installed, the central axes of the three completely coincide.

[0048] It is easy to understand that, in the serial direction of the damping cable 703 from the two-axis joint damping disc 1 to the upper arm support 2, the fifth pulley mounting hole is set on the extended platform of the pulley block base 102, and the redirecting pulley 105 is installed through the third pulley mounting hole. A stop component is set at the redirecting pulley 105, and the stop component includes a baffle 106 arranged at both ends of the redirecting pulley shaft. A pin 107 is connected in series with a retaining ring 108 in the outer hole of the baffle 106 to prevent the damping cable 703 from falling out of the groove, and the pin 107 is fixed by a cotter pin 109.

[0049] In order to ensure the versatility of the robot and avoid destructive modification of the robot, three groups of arm brackets 2 are set on the second connecting rod arm 14 of the robot to provide damping force application points, and the interval between adjacent two arm brackets 2 is set, referring to Figure 4 and Fig.12 As shown, the boom support 2 includes a boom support base plate 201 and a boom support U-shaped plate 202. After the two are fitted together, the rectangular cross-section of the middle cavity is slightly larger than the cross-section of the second connecting rod boom 14 of the robot. Three bolt through holes are respectively provided at the fitting parts of the two, and the second connecting rod boom 14 of the robot is locked by the first bolt 203 and the first nut 204. The boom support base plate 201 and the boom support U-shaped plate 202 are fitted to the side of the robot arm and are provided with a boom rubber anti-skid pad 205 by gluing. The boom rubber anti-skid pad 205 can prevent wear or scratches caused by hard contact between the boom support 2 and the second connecting rod boom of the robot. At the same time, the elastic deformation of the boom rubber anti-skid pad 205 can increase the friction force, so as to prevent the boom support 2 from sliding with the second connecting rod boom 14 of the robot after being pulled by the damping cable 703. The thickness and shape of the boom rubber anti-skid pad 205 are selected according to the installation effect and are not specifically limited here.

[0050] Since the side of the robot's second connecting rod arm 14 is arc-shaped and the cross-sectional shape is not fixed, in order to ensure that the upper arm bracket 2 is completely fixed to the robot, three sets of adaptive clamps are arranged on the upper arm bracket 2 close to the robot's end effector to prevent the upper arm bracket 2 from sliding along the axis direction of the robot's fourth connecting rod 17. Three positioning and mounting holes are opened on the side of the upper arm bracket U-shaped plate 202 on the corresponding side for installing adaptive clamps. The adaptive clamps include an adjusting bolt 206, a welding nut 207, a fastening hinge 208 and a clamp leaf 209. The welding nut 207 is fixed to the upper arm by welding. On the positioning and mounting hole of the U-shaped plate 202 of the upper arm bracket, the adjusting bolt 206 passes through the welding nut 207 and is threadedly connected to the fastening hinge 208 at the end. The fastening hinge 208 and the clamping claw leaf 209 are fixed by hinged means, and the hinge hole is installed through the cotter pin 109. The clamping claw leaf 209 is close to the side of the mechanical arm and is provided with a non-slip rubber pad by gluing to increase the fastening force. The tightness between the clamping claw leaf 209 and the side of the mechanical arm is adjusted by tightening the adjusting bolt 206. At the same time, the clamping claw leaf 209 rotates along the fastening hinge 208 to adapt to the curvature of the side of the mechanical arm.

[0051] Specifically, refer to Figure 4 As shown, a boom ring fixing part 210 is arranged on the side of the boom bracket 2 away from the end effector of the robot, and five threaded holes are evenly arranged on the side of the boom bracket U-shaped plate 202 on the corresponding side, a convex cavity is arranged inside the boom ring fixing part 210, and five bolt countersunk holes are arranged inside the convex cavity, which is fixed to the boom bracket U-shaped plate 202 by a second bolt 211, a second nut 212 is arranged in the convex cavity, and a third nut 213 is arranged outside the convex cavity, and the second nut 212 and the third nut 213 are arranged outside the convex cavity. The threads of the three nuts 213 are rotated in opposite directions, and the eye bolt 214 passes through the third nut 213 and the convex cavity in sequence and is screwed into the second nut 212, wherein the eye bolt 214 can adjust the fixed position along the cavity of the boom eye fixing piece 210 according to the passage mode of the damping cable 703, and tightening the eye bolt 214 can make the second nut 212 and the third nut 213 clamp the boom eye fixing piece 210, thereby preventing the eye bolt 214 from moving due to the traction force of the damping cable 703.

[0052] refer to Figure 5 and Fig.12As shown, two groups of jib brackets 3 are arranged on the parallel-link jib of the robot, and the jib brackets 3 are used to provide damping force application points for the damping cable 703. The jib brackets 3 include two relatively arranged jib bracket U-shaped plates 301. After the two are fitted together, the rectangular cross-section of the middle cavity is slightly larger than the cross-section of the robot parallel-link jib. A bolt through hole is provided at each fitting position of the two. The parallel-link jib 15 of the robot is locked by another first bolt 203 and a first nut 204. The jib bracket U-shaped plate 301 is fitted on the side of the parallel jib and is provided with a jib rubber anti-skid pad 302 by gluing. The jib rubber anti-skid pad 302 has the same function as the upper arm rubber anti-skid pad 205. The thickness and shape of the rubber anti-skid pad are selected according to the installation effect and are not specifically limited here.

[0053] It is easy to understand that a jib lifting eye fixing part 303 is arranged on the side of the jib bracket 3 close to the second connecting rod arm of the robot, and two threaded holes are evenly opened on the side of the jib bracket U-shaped plate 301 on the corresponding side. A convex cavity is also arranged inside the jib lifting eye fixing part 303, and two bolt countersunk holes are correspondingly arranged inside the second convex cavity. The second bolt 211 is fixed on the jib bracket U-shaped plate 301, the second nut 212 is arranged in the convex cavity, and the third nut 213 is arranged on the outside of the convex cavity. The installation method of the jib lifting eye fixing part 303 on the jib bracket 3 is the same as the installation method of the boom lifting eye fixing part 210 in the boom bracket 2.

[0054] refer to Figure 6 and Fig.12 As shown, in order to reduce the influence of the stiffness enhancement mechanism on the working range of the industrial robot, four fixed brackets 10 are installed at the multiple threaded mounting holes reserved at the first joint of the robot, and the base bracket 4 is fixed to the first joint of the robot through the fixed brackets 10. The base bracket 4 is connected to the fixed bracket 10 through a third bolt 404 and a boat-shaped nut 405, so that the stiffness enhancement mechanism can rotate with the one-axis joint of the robot without interference. The fixed bracket can specifically be a support block.

[0055] In this embodiment, the main body of the base bracket 4 is composed of four first support frames 401 with a length of 900 mm, two second support frames 402 with a length of 1060 mm and 45° beveled surfaces at both ends, and two third support frames 403 with a length of 611 mm. The cross-sectional size parameters of the support frames are selected according to actual installation requirements and are not specifically limited here.

[0056] Four first support frames 401 and two second support frames 402 form two groups of right-angled triangle frames, and a third support frame 403 is set at the right angle point of the two groups of triangle frames for connection. Another third support frame 403 is set between the two first support frames 401 connected to the fixed bracket according to the actual installation conditions as a reinforcement beam. Each aluminum profile is connected by a right-angle bracket 406, an acute angle bracket 407 or an obtuse angle bracket 408 according to the angle space. The first support frame 401 is provided with a mounting plate 409 along the direction perpendicular to the bottom surface of the robot base. The mounting plate 409 is provided with 15 rows of transverse mounting holes parallel to the third support frame 403. The transverse mounting holes between different rows are staggered. The fixing holes can be selected as needed to facilitate the adjustment of the position of the damper component 6. The support frames, angle brackets, and mounting plates 409 in the base bracket 4 are fixed by boat nuts 405 and third bolts 404.

[0057] It should be explained that the tensioning device 5 includes a tensioning bracket, a tensioning adjustment assembly and a tensioning clamping assembly. Figure 7 As shown, the tensioning bracket is composed of two fourth support frames 501 with a length of 300 mm and 45° beveled surfaces at both ends, and a fifth support frame 502 with a length of 500 mm and 45° beveled surface at one end, wherein the two fourth support frames 501 are placed vertically, and the fifth support frame 502 is added as the hypotenuse to form a right-angle triangle frame, which is connected by angle brackets of different angles, third bolts 404 and boat-shaped nuts 405. The tensioning bracket is vertically arranged between the two third support frames 403 of the base bracket 4, and is connected by angle brackets, third bolts 404 and boat-shaped nuts 405. The right-angle point of the tensioning bracket is arranged on the third support frame 403 close to the end effector side of the robot, and the tensioning bracket can be moved laterally along the third support frame 403 by removing the bolts, so as to facilitate the adjustment of the position of the tensioning device 5.

[0058] refer to Figure 8As shown, the tensioning adjustment assembly includes two clamps 503 symmetrically fixed to the fifth support frame 502 by a third bolt 404 and a boat-shaped nut 405, a bearing seat hole is opened on the clamp 503, a deep groove ball bearing 504 is arranged in the bearing seat hole, and a gear shaft 505 arranged between the two clamps 503 passes through the deep groove ball bearing 504 for connection, one end of which passes through the clamp 503 and is fixedly connected to the rotating wheel 506 by a thread. A rack 507 is slidably arranged on the upper side of the fifth support frame 502, and the rack 507 is meshed with the gear shaft 505. Four threaded holes are provided on the rack 507 near the end effector side of the robot, and the cylindrical clamping shaft 509 is fixedly connected by a fourth bolt 508. A pulley groove is provided at the end of the cylindrical clamping shaft 509, and the fifth pulley is fixed between the pulley grooves by a pulley fastening nut. Similar to the redirection pulley 105 arranged on the extended platform of the two-axis joint damping disk 1, baffles 106 and baffle rings 108 are arranged at both ends of the pulley, and a pin 107 is arranged through the baffle ring. The damping cable passes around the pulley and then passes through the baffle ring to prevent the damping cable 703 from falling out of the groove.

[0059] It is easy to understand that the tensioning adjustment component can slide along the fifth support frame 502. After the position of the tensioning adjustment component is preliminarily determined according to specific needs, the rotating wheel 506 is shaken, the gear shaft 505 and the rotating wheel 506 rotate synchronously, and at the same time, the rack 507 reciprocates with the gear at the gear shaft 505, and the extended length of the cylindrical clamping shaft 509 also changes with the movement of the rack 507, thereby adjusting the pre-tensioning degree of the damping cable 703.

[0060] In addition, a tensioning clamping assembly is provided on the cylindrical clamping shaft 509, and the tensioning clamping assembly includes a first clamping block 510 and a second clamping block 511, wherein the first clamping block 510 is fixed on the fifth support frame 502 through the third bolt 404 and the boat-shaped nut 405, and the second clamping block 511 is fixed on the first clamping block 510 through two locking bolts 512, and an arc hole is provided at the junction of the two clamping blocks, and a through hole is formed by two arc plates, and the diameter of the through hole is smaller than the diameter of the cylindrical clamping shaft 509. After the initial preload force adjustment of the damping rope 703 is completed, the two locking bolts 512 can be tightened to make the two clamping blocks clamp the cylindrical clamping shaft 509, thereby preventing the tensioning device 5 from moving.

[0061] It is easy to understand that each component in the tensioning bracket and the base bracket 4 can be an existing industrial aluminum profile, which is convenient for installation.

[0062] refer to Fig. 9 , Fig.10 and Fig.11As shown, the damper component 6 includes two sliding damping components and a tensioning pulley 601. The tensioning pulley is arranged between the two sliding damping components. The tensioning pulley 601 is similar to the redirecting pulley 105 arranged on the extended platform of the two-axis joint damping disk 1. By arranging a baffle 106 and a baffle ring 108 on the side of the tensioning pulley 601, the damping cable 703 is prevented from being degrooved at the tensioning pulley 601. The damper component 6 is fixed to the mounting plate by bolts and nuts. The sliding damping component can automatically adjust the movement range of the damping cable according to the movement state of the robot arm during the processing, and effectively apply a stable damping force to the damping cable.

[0063] Specifically, the sliding damping assembly includes two coaxially arranged dampers, and the damper is a viscous damper 602. The two viscous dampers 602 are symmetrically distributed along the first axis, and the first axis is perpendicular to the axis of the viscous damper 602. The viscous damper 602 is a magnetorheological damper, and the damping strength can be changed by actively controlling the current according to the robot structure modal matching requirements during use. The damper center block 603 is set at the symmetric center of the two viscous dampers 602, and the damper center block 603 is hinged to the end of the piston rod through the pin 604 and the cotter pin 109; through the setting of the damper, the sliding damping assembly provides continuous damping internal force for the damping cable 703 during the operation of the robot, and compensates for the spatial position change of the damping cable 703.

[0064] In this embodiment, a guide hole is provided in the middle of the damper center block 603, and a damper center rod 605 is arranged in the guide hole. The damper center rod 605 provides sliding support for the sliding damping assembly. The damper center rod 605 is provided with tension springs 606 on both sides along the first axis, and the tension spring 606 passes through the damper center rod. A damper base 607 is provided at one end of the damper center rod 605, and the two are fixed by threaded connection. The damper base 607 is connected to the mounting plate 40 by bolts and nuts. 9 fixed; a damper stop block 608 is provided at the other end of the damper center rod, a guide hole is provided in the center of the damper stop block 608 for the unfixed side of the damper center rod 605 to pass through, and the tension spring is limited by the damper stop block. One of the two tension springs 606 is located between the damper stop block 608 and the damper center block 603, and the other is located between the damper center block 603 and the damper base 607, and is fixed by screwing in the limit ear plates provided in each part; A threaded hole is provided on the side of the damper limit block 608, which is fixedly connected to the tensioning pulley 601 in the damper component 6 by threads. Two connecting rods 609 are respectively arranged between the end of the viscous damper 602 and the damper limit block 608 and the damper base 607. The pin shaft 604 and the cotter pin 109 are hinged to the end of the viscous damper 602 through the connecting pad 610. Connecting ear seats are arranged on the damper limit block 608 and the damper base 607, and the pin shaft 604 and the cotter pin 109 pass through the connecting ear seats to be hinged to the connecting rods 609. After the four connecting rods 609 are installed, a diamond-shaped hinged connecting rod mechanism is formed to ensure the stability of the structural setting of the damper component.

[0065] refer to Fig.11 and Fig.12 As shown, the travel mode of the damping cable 703 is related to the number and position of the boom support 2 and the auxiliary arm support 3. In this embodiment, three boom supports 2 are provided, and two auxiliary arm supports 3 are provided. The positions of the eyebolts 214 of the boom support 2 and the auxiliary arm support 3 are adjusted to appropriate positions according to the actual application scenario, ensuring that the first eyebolt at the boom support and the connected redirection pulley 105 are located in the same plane (the plane is parallel to the side of the second boom of the robot) to prevent the damping cable 703 from being disengaged during operation.

[0066] In addition, the closed cable assembly 7 further comprises a first tension sensor 701 , a second tension sensor 702 and a damping cable 703 . The damping cable 703 can be divided into a first section of damping cable 7031 and a second section of damping cable 7032 .

[0067] The arrangement method of the stiffness improvement mechanism comprises the following steps: the first section of the damping cable 7031 is passed through the eye bolts 214 on the boom support 2 and the jib support 3 in sequence (the passing method is to pass through in sequence in a cross manner), and the first pulley at the first steering pulley support 8, and then connected to the second tension sensor 702; the second section of the damping cable 7032 is passed through the pulley block 103 on the two-axis joint damping disk 1, the second pulley on the second steering pulley support 9, the fifth pulley on the tensioning device 5, and the tensioning pulley 601 on the damper component 6 in sequence; the first end of the first section of the damping cable 7031 is connected to the first end of the second section of the damping cable 7032 through the first tension sensor 701, and the second end of the first section of the damping cable 7031 is connected to the second end of the second section of the damping cable 7032 through the second tension sensor 702.

[0068] In order to ensure good flutter suppression efficiency, the damping cable 703 can be made of plant fiber rope, chemical fiber rope, and steel wire rope. It can be understood that according to the characteristics of the cable material, its modal frequency also varies greatly. Before selection, the modal matching characteristics between the cable parameters and the joints should be ensured through multi-physics field simulation and experimental testing based on the modal frequency of the robot joints, so that resonance is formed between the damping cable and the joint, thereby absorbing the flutter energy on the joint to the cable for dissipation. The selection method of the damping cable 703 has a relatively mature technology, which will not be introduced in detail here.

[0069] Embodiment 2 This embodiment discloses a working method for a stiffness enhancement mechanism of a robot, including the following contents: like Fig.11 and Fig.12 As shown, the robot is in a zero-position posture. Due to the tension provided by the tension spring 606 in the damper component 6, the tension pulley 601 is in a retracted state. The piston rod of the viscous damper 602 is mostly extended, but still provides a damping internal force for the closed cable assembly 7. The tensioning device 5 abuts against the damping closed cable assembly 7 and deforms it to provide initial tensioning force according to actual application needs.

[0070] refer to Fig.13 As shown, in this embodiment, the robot end effector is at the farthest point in the workspace, and the boom support 2 and the jib support 3 are locked and have no obvious position change. The tension spring in the damper component 6 is stretched to the limit position due to the traction of the closed cable assembly 7. At this time, the tension pulley 601 is in a fully stretched state, and the piston rod of the viscous damper 602 is mostly retracted, but it still provides damping internal force for the closed cable assembly 7. At this time, the damper component 6 makes a certain compensation for the spatial position change of the closed cable assembly 7, so the tension state of the damping cable 703 does not change significantly.

[0071] Specifically, the tensioning device 5, the eyebolt 214, the redirecting pulley 105, the damper component 6 and the damping cable 703 can be adjusted according to actual needs until the readings of the first tension sensor 701 and the second tension sensor 702 are similar and within a preset range.

[0072] In an ideal state, the readings on the first tension sensor 701 and the second tension sensor 702 are completely consistent, but in actual situations, the tensioning device 5 can only ensure the modal matching of the robot in the initial state. After the processing starts, due to the change in the spatial position of the damping cable 703 and the friction on the contact surface, there will be deviations in the readings on the first tension sensor 701 and the second tension sensor 702. Therefore, when installing the damping cable 703, a lubricating medium should be applied to its surface to reduce the friction coefficient, and an active feedback control strategy should be used to adjust the damping strength of the viscous damper 602 in real time to achieve real-time matching of the modal between the damping cable 703 and the robot joint.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A stiffness enhancement mechanism for a robot, characterized in that: The invention comprises a base bracket arranged at the first joint of the robot, the base bracket supports the damper component, a two-axis joint damping disk is arranged at the second joint of the robot, a pulley group is arranged at the two-axis joint damping disk, a boom bracket is arranged at the second connecting rod boom of the robot, and a jib bracket is arranged at the parallel connecting rod jib of the robot. The damping cable is connected with the boom bracket and the jib bracket and then is wound around the damper component, and continues to pass through the tensioning device and bypasses the pulley group at the two-axis joint damping disk. The torque direction of the damping cable is changed by the pulley group, and the damping cable provides a damping torque to the robot.

2. A stiffness enhancement mechanism for a robot according to claim 1, characterized in that: It also includes a first pulley and a second pulley, the first pulley is arranged at the hinge between the parallel link auxiliary arm and the second link main arm, the second pulley is arranged below the two-axis joint damping disk, and the damping cable is arranged to bypass the first pulley and the second pulley to change the direction of the damping cable through the first pulley and the second pulley.

3. A stiffness enhancement mechanism for a robot according to claim 2, characterized in that: The damping cable comprises two sections, the first section of the damping cable passes through the boom support, the jib support and the first pulley arrangement in sequence, the second section of the damping cable passes through the pulley block, the second pulley, the tensioning device and the damper component in sequence, the first section of the damping rope is connected to the second section of the damper through a tension sensor to form a closed cable assembly.

4. A stiffness enhancement mechanism for a robot according to claim 1, characterized in that: The two-axis joint damping disk includes a pulley block base, which is coaxially connected to the second joint, and the pulley block base supports the pulley block. The pulley block includes a third pulley and a fourth pulley. There are multiple third pulleys and at least two fourth pulleys. The multiple third pulleys are arranged along the circumference of the pulley block base, and the fourth pulley is located on the inner side of the third pulley. One side of the pulley block base is protruding, and a redirecting pulley is arranged at the protruding part of the pulley block base. The damping cable passes through part of the third pulley, the fourth pulley, another third pulley and the redirecting pulley in sequence, so that the damping cable is located at a section of the redirecting pulley and the boom bracket that has the same direction as the second connecting rod boom.

5. A rigidity enhancement mechanism for a robot according to claim 4, characterized in that: A stopper is also provided at the protrusion of the pulley block base, and the stopper connects the pulley shaft of the redirecting pulley and the protrusion of the pulley block base, so that a distance is set between the stopper and the redirecting pulley to limit the damping cable.

6. A stiffness enhancement mechanism for a robot according to claim 1, characterized in that: The boom bracket is provided with at least two, the boom bracket is fixed to the circumferential direction of the boom of the second connecting rod, the eye bolt is installed on the side of the boom bracket, the damping cable is arranged through the eye bolt of the boom bracket, and the eye bolt is installed on the boom bracket through the boom eye fixing piece; The jib bracket is provided with at least one, the jib bracket and the boom bracket are arranged alternately, the jib bracket is fixed to the circumferential direction of the parallel connecting rod jib, the eye bolt is installed on the side of the jib bracket, the damping cable passes through the eye bolt at the jib bracket, and the eye bolt is installed on the jib bracket through the jib eye fixing piece; The structures of the boom lifting eye fixing piece and the jib lifting eye fixing piece are the same. Both of them include a convex cavity, a second nut is arranged in the convex cavity, and a third nut is arranged outside the convex cavity. The lifting eye bolt passes through the third nut and the second nut in sequence.

7. A stiffness enhancement mechanism for a robot according to claim 6, characterized in that: An adaptive clamping claw is arranged on the side of the boom bracket, and the adaptive clamping claw includes an adjusting bolt, which passes through a welding nut and the side of the boom bracket, and the welding nut is fixed to the side of the boom bracket. The end of the adjusting bolt is connected to a fastening hinge, and the fastening hinge is hingedly connected to the clamping claw leaf petal. The clamping claw leaf petal can rotate along the fastening hinge to adapt to the second connecting rod boom.

8. A stiffness enhancement mechanism for a robot according to claim 1, characterized in that: The damper component includes two sliding damping assemblies, a tensioning pulley is arranged between the two sliding damping assemblies, and the damping cable is arranged around the tensioning pulley. The sliding damping assembly includes two dampers arranged oppositely, and the telescopic ends of the two dampers are connected to the damper center block. The damper center rod is arranged through the damper center block. The damper center rod passes through one end of the damper center block and is connected to the base bracket, and the other end of the damper center rod passes through the damper limit block. The damper center rod is located on both sides of the damper center block and is respectively covered with tension springs. The fixed end of the damper is connected to the base bracket and the damper limit block through a connecting rod.

9. A stiffness enhancement mechanism for a robot according to claim 1, characterized in that: The tensioning device includes a tensioning bracket, which is installed on the base bracket. The position of the tensioning bracket relative to the base bracket is adjustable. The tensioning bracket supports a tensioning adjustment component and a tensioning clamping component. The tensioning adjustment component includes a moving part, which is slidably installed on the tensioning bracket. The moving part is connected to the cylindrical clamping shaft. A fifth pulley is arranged at one end of the cylindrical clamping shaft away from the moving part. The damping cable is arranged to bypass the fifth pulley so as to adjust the tension of the damping cable through the moving part. A stop part is arranged on one side of the fifth pulley.

10. A rigidity enhancement mechanism for a robot according to claim 9, characterized in that: The tensioning and clamping assembly clamps the cylindrical clamping shaft and is capable of locking the cylindrical clamping shaft. The fifth pulley is arranged below the damper component, and the cylindrical clamping shaft is arranged tilted upward relative to the bottom of the base bracket.

11. A rigidity enhancement mechanism for a robot according to claim 1, characterized in that: The base support includes a bottom frame, which supports a vertical frame, and the vertical frame supports a mounting plate. The mounting plate is provided with multiple layers of mounting holes, and the mounting holes of two adjacent layers of mounting holes are staggered. The damper component is installed on the mounting plate through the mounting holes.

12. A working method for a stiffness enhancement mechanism of a robot according to any one of claims 1 to 11, characterized in that: It includes the following: A base bracket is arranged at the first joint of the robot, the base bracket supports the damper component, a two-axis joint damping disk is arranged at the second joint, a pulley block is arranged at the two-axis joint damping disk, a big arm bracket is arranged at the second connecting rod big arm, and a jib bracket is arranged at the parallel connecting rod jib; The damping cable is connected to the boom support and the auxiliary arm support and then goes around the damper component, and then passes through the tensioning device and around the pulley block at the two-axis joint damping plate; The robot is in a zero-position posture, the damper component provides a damping internal force for the damping cable, and the tensioning device abuts against the damping cable and deforms it to provide an initial tensioning force according to actual application requirements; During the working process of the first arm, the second link arm, the parallel link jib and the third arm of the robot, a damping torque is introduced to the second joint, the second link arm and the parallel link jib through the damping cable to realize the dissipation of the flutter energy of the joint structure.

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