Rigidity-variable buffering and damping mechanism and robot grinding device with rigidity-variable buffering and damping mechanism

Abstract

The invention discloses a variable-rigidity buffering and damping mechanism, and relates to the technical field of robot precision machining, the variable-rigidity buffering and damping mechanism comprises a shell and a variable-rigidity assembly, the variable-rigidity assembly comprises an upper variable-rigidity disc, a transmission shaft penetrates through the middle of the upper variable-rigidity disc, and the top end of the transmission shaft penetrates out of the shell to the outer side of the shell; the bottom end is positioned in the shell; the lower variable-stiffness disc is located below the upper variable-stiffness disc, a central through hole of the lower variable-stiffness disc is in clearance fit with the transmission shaft, a transmission rod penetrating out of the bottom wall of the shell is fixed to the bottom wall of the lower variable-stiffness disc, a cavity is formed in the transmission rod, and the bottom of the transmission rod is detachably connected with an execution working end; the top end of the elastic rod is fixed on the bottom wall of the upper rigidity-variable disc, and the bottom end of the elastic rod is in clearance fit with the lower rigidity-variable disc; the outer side of the elastic rod is sleeved with a spring, and the two ends of the spring abut against the position between the upper rigidity-variable disc and the lower rigidity-variable disc. The execution working end is stressed, the lower variable-stiffness disc moves in the axial direction of the transmission shaft, the effective length of the elastic rod is changed, and self-adaptive stiffness adjustment is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of robot precision machining, and more specifically to a variable stiffness device for robot grinding processes, especially applicable to a buffer and shock absorption mechanism between a driving part and a grinding tool. Background Art

[0002] Robot machining is flexible and highly efficient, and has gradually replaced manual machining with unstable machining quality and slow machining speed. In the field of high-precision manufacturing, such as the automotive, aerospace, and electronics manufacturing industries, grinding end effectors are widely used for surface treatment and fine machining, and grinding robot systems are widely applied in industrial fields.

[0003] In existing robot grinding devices, an electric spindle or a pneumatic spindle is usually rigidly connected to a grinding head (such as patents: CN106393131A, CN111906664A, CN117400104A, etc.) to ensure the stiffness of the grinding system and achieve high grinding accuracy. However, due to the large stiffness of the grinding system, there are impacts and vibrations during the transition stage of the system from the no-load running state to the load-bearing running state. The large impacts and vibrations may affect the stability of the system and even cause serious damage to the system body, the surface quality of the machined workpiece, etc.

[0004] To alleviate the impact, some technologies introduce rubber pads or hydraulic dampers, etc., to absorb vibration energy by reducing the system stiffness; however, such solutions have a significant decrease in stiffness under load conditions and cannot meet the requirements of high-precision grinding.

[0005] Therefore, how to provide a buffer and shock absorption mechanism that can adaptively adjust stiffness to buffer the impacts and vibrations existing during the transition stage of the robot grinding system from the no-load running state to the load-bearing running state is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a variable stiffness buffer and shock absorption mechanism, aiming to solve the above technical problems.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A variable stiffness buffer and shock absorption mechanism, including a housing, the interior of the housing is hollow, and further includes a variable stiffness component installed inside the housing, the variable stiffness component includes:

[0009] An upper variable stiffness disk, a transmission shaft is fixedly penetrated through the middle of the upper variable stiffness disk, the top end of the transmission shaft passes through the top wall of the housing and extends to the outside of the housing, and the bottom end of the transmission shaft is located inside the housing;

[0010] Lower variable stiffness disk, the lower variable stiffness disk is located below the upper variable stiffness disk, the central through hole of the lower variable stiffness disk is in clearance fit with the transmission shaft, and a transmission rod passing through the bottom wall of the housing is fixed to its bottom wall. There is a cavity inside the transmission rod, so that the bottom end of the transmission shaft can be inserted into the cavity. The bottom of the transmission rod is detachably connected with an execution working end;

[0011] Elastic rod, the top end of the elastic rod is fixed on the bottom wall of the upper variable stiffness disk, and its bottom end is in clearance fit with the lower variable stiffness disk; A spring is sleeved outside the elastic rod, and both ends of the spring are pressed tightly between the upper variable stiffness disk and the lower variable stiffness disk;

[0012] The execution working end is stressed, so that the lower variable stiffness disk moves axially along the transmission shaft to change the effective length of the elastic rod, realizing adaptive stiffness adjustment.

[0013] Through the above technical solutions, in a variable stiffness buffer and shock absorption mechanism provided by the present invention, driven by external power, the transmission shaft drives the upper variable stiffness disk to rotate, and then drives the lower variable stiffness disk to rotate through the elastic rod. When the execution working end is stressed, the lower variable stiffness disk moves axially along the transmission shaft, and under the action of the spring, the distance from the upper variable stiffness disk is adjusted to change the effective length of the elastic rod, realizing the adaptive dynamic switching between low stiffness (buffer and shock absorption) during no-load and high stiffness (high-precision force transmission) during load; This characteristic of adaptive stiffness adjustment can provide appropriate buffer and shock absorption effects under different working conditions, effectively reduce the influence of vibration and impact on the equipment, improve the stability and reliability of the equipment operation, and extend the service life of the equipment; It solves the technical problems that there are impact vibrations in the transition stage from no-load to load in traditional rigid connections, while flexible connections cannot meet the high-precision requirements; The present invention balances the contradiction between buffering and force transmission through a mechanical variable stiffness design.

[0014] Preferably, in the above variable stiffness buffer and shock absorption mechanism, the number of the elastic rods is multiple, and the multiple elastic rods are circumferentially arranged between the upper variable stiffness disk and the lower variable stiffness disk. The multiple elastic rods are circumferentially arranged to disperse the torque and axial force, avoid the overload failure of a single rod, and improve the reliability of the system; The symmetrical layout reduces eccentric vibration and ensures the smooth rotation of the lower variable stiffness disk.

[0015] Preferably, in the above variable stiffness buffer and shock absorption mechanism, the elastic rod is a cylindrical rod, and its material is beryllium copper material. The bending stiffness K bend of the elastic rod is calculated by the formula:

[0016] K bend = 3EI / l 3

[0017] Among them, E is the Young's modulus of the elastic rod; I is the moment of inertia of the cross-section of the elastic rod; l is the effective length of the elastic rod. The beryllium copper elastic rod has a high elastic modulus and strong fatigue resistance; the bending stiffness is accurately calculated by the formula to guide parameter optimization; the combination of the beryllium copper rod and the formula design improves the predictability and consistency of the stiffness.

[0018] Preferably, in the above variable stiffness buffer and shock absorber mechanism, the calculation formula for the Young's modulus of the elastic rod is E = 131×10 9 Pa;

[0019] The calculation formula for the moment of inertia of the cross-section of the elastic rod is I = πd 4 / 64, where d is the diameter of the elastic rod. Defining the values of the Young's modulus and the moment of inertia of the cross-section ensures the repeatability of the design; in practical applications, according to different working environments and load requirements, the moment of inertia of the cross-section can be changed by adjusting the diameter of the elastic rod, thereby achieving precise control of the bending stiffness, providing a more accurate calculation method for the precise design and performance evaluation of the mechanism, and helping to improve the design quality and performance of the mechanism.

[0020] Preferably, in the above variable stiffness buffer and shock absorber mechanism, the part of the transmission shaft located inside the housing is a stepped shaft, the stepped shaft is in clearance fit with the central through hole, and the shoulder of the stepped shaft is used to limit the maximum axial displacement of the lower variable stiffness disk to ensure rigid contact under load conditions. The shoulder of the stepped shaft limits the maximum axial displacement of the lower variable stiffness disk to prevent excessive compression of the spring or structural damage caused by over-travel; under load conditions, the shoulder contacts the lower variable stiffness disk to form a rigid force transmission path to ensure grinding accuracy; at the same time, it can maintain the stability and reliability of the mechanism under extreme loads.

[0021] Preferably, in the above variable stiffness buffer and shock absorber mechanism, a first annular groove is formed on the inner bottom wall of the housing, and a first annular magnet is installed in the first annular groove; a second annular groove is formed on the upper surface of the lower variable stiffness disk, and a second annular magnet is installed in the second annular groove; the first annular magnet and the second annular magnet are opposite in the same pole. The repulsive force is generated between the two annular magnets with opposite poles to prevent the lower variable stiffness disk from contacting the bottom wall of the housing, and the magnetic repulsion provides additional axial resistance to assist the spring in adjusting the position of the lower variable stiffness disk.

[0022] Preferably, in the above variable stiffness buffer and shock absorber mechanism, the working end is a grinding assembly, a polishing assembly or a cutting assembly.

[0023] Preferably, in the above variable stiffness buffer and shock absorption mechanism, a first through hole and a second through hole are respectively formed in the top and bottom of the housing. The top end of the transmission shaft passes through the first through hole and extends above the housing, and the bottom end of the transmission rod passes through the second through hole and extends below the housing.

[0024] Preferably, in the above variable stiffness buffer and shock absorption mechanism, a deep groove ball bearing is installed in the first through hole, and the transmission shaft is fixed to the inner ring of the deep groove ball bearing; a bushing is installed in the second through hole, and the bushing is in clearance fit with the transmission rod so that the transmission rod can rotate and axially move.

[0025] The present invention also discloses a robot grinding device, which includes a robot body and the above variable stiffness buffer and shock absorption mechanism; a grinding end effector is connected to the robot body, the housing is fixed to the grinding end effector, and the driving part of the grinding end effector is in transmission connection with the transmission shaft extending outside the housing. Combining the variable stiffness buffer mechanism with the robot body and the grinding end effector realizes high-precision adaptive grinding; during the working process, it can automatically adjust the stiffness according to different situations of the contact surface, adapt to the workpiece surfaces with different hardness and roughness, improve the grinding quality and efficiency, and reduce the influence of vibration and impact during the grinding process on the robot body and the workpiece.

[0026] It can be seen from the above technical solutions that compared with the prior art, the present invention discloses a variable stiffness buffer and shock absorption mechanism and a robot grinding device having the same, and has the following beneficial effects:

[0027] 1. By the compression and rebound of the spring, the present invention adjusts the distance between the lower variable stiffness disc and the upper variable stiffness disc, changes the effective length of the elastic rod, and realizes the adaptive switching between low stiffness buffer under no-load and high stiffness force transmission under load; reduces the impact and vibration existing in the transition stage from no-load operation state to load operation state, improves the grinding quality, and prolongs the service life of the equipment.

[0028] 2. Multiple elastic rods of the present invention are circumferentially symmetrically distributed to disperse the load, avoid single rod overload, and improve the force transmission stability.

[0029] 3. The present invention utilizes the same magnetic poles of the annular magnets on the housing and the lower variable stiffness disc to maintain the relative positions of the components during normal operation, improving the stability; assisting the spring to buffer during impact, making the variable stiffness process smoother, and enhancing the adaptability of the mechanism to impact and vibration.

[0030] 4. The through holes of the housing of the present invention are provided, and the internal bearings and bushings are installed, providing a reasonable space and movement conditions for the transmission shaft and the transmission rod, realizing reliable power transmission and normal grinding operation, reducing friction and wear, reducing energy loss, improving transmission efficiency and service life, and ensuring the axial movement and rotational coordination of the transmission rod under the action of the variable stiffness buffer and shock absorption mechanism.

[0031] 5. The working end of the present invention adopts a detachable connection method, which is convenient for replacing different types of tools, such as grinding tools, polishing tools or cutting tools; shortening the equipment downtime, improving production efficiency, enhancing the flexibility and adaptability of the robot grinding device, and meeting the diverse production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0033] Figure 1 The drawings are the structural schematic diagrams of the variable stiffness buffer and shock absorption mechanism provided by the present invention;

[0034] Figure 2 The drawings are Figure 1 The cross-sectional views of the drawings;

[0035] Figure 3 The drawings are the structural schematic diagrams of the variable stiffness components provided by the present invention;

[0036] Figure 4 The drawings are the structural schematic diagrams of the upper variable stiffness disks provided by the present invention;

[0037] Figure 5 The drawings are the structural schematic diagrams of the lower variable stiffness disks provided by the present invention;

[0038] Figure 6 The drawings are the structural schematic diagrams of the housing bottom covers provided by the present invention.

[0039] Wherein:

[0040] 1 - housing; 11 - first annular groove; 12 - first annular magnet; 13 - first through hole; 131 - deep groove ball bearing; 14 - second through hole; 141 - bushing; 15 - bottom end cover; 2 - upper variable stiffness disk; 21 - transmission shaft; 211 - shaft shoulder; 3 - lower variable stiffness disk; 31 - transmission rod; 311 - cavity; 32 - second annular groove; 33 - second annular magnet; 4 - elastic rod; 5 - spring; 6 - working end; 61 - grinding tool; 62 - locking nut. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] See the attached Figure 1 to the attached Figure 6 In the embodiments of the present invention, a variable stiffness buffer and shock absorption mechanism is disclosed, which includes a housing 1 with a hollow interior. It further includes a variable stiffness component installed inside the housing 1. The variable stiffness component includes:

[0043] An upper variable stiffness disk 2, in the middle of which a transmission shaft 21 is fixedly penetrated. The top end of the transmission shaft 21 penetrates through the top wall of the housing 1 and extends to the outside of the housing. The bottom end of the transmission shaft 21 is located inside the housing 1;

[0044] A lower variable stiffness disk 3, which is located below the upper variable stiffness disk 2. The central through hole of the lower variable stiffness disk 3 is in clearance fit with the transmission shaft 21, and a transmission rod 31 that penetrates through the bottom wall of the housing 1 is fixed to its bottom wall. A cavity 311 is provided inside the transmission rod 31, so that the bottom end of the transmission shaft 21 can be inserted into the cavity 311. The bottom of the transmission rod 31 is detachably connected to an execution working end 6;

[0045] An elastic rod 4, the top end of which is fixed to the bottom wall of the upper variable stiffness disk 2, and its bottom end is in clearance fit with the lower variable stiffness disk 3; A spring 5 is sleeved outside the elastic rod 4, and both ends of the spring 5 are abutted between the upper variable stiffness disk 2 and the lower variable stiffness disk 3;

[0046] When the execution working end 6 is stressed, the lower variable stiffness disk 3 moves axially along the transmission shaft 21 to change the effective length of the elastic rod 4, realizing adaptive stiffness adjustment.

[0047] To further optimize the above technical solution, the number of elastic rods 4 is multiple, and the multiple elastic rods 4 are circumferentially arranged between the upper variable stiffness disk 2 and the lower variable stiffness disk 3; In this embodiment, the number of elastic rods is 4.

[0048] To further optimize the above technical solution, the elastic rod 4 is a cylindrical rod, and its material is beryllium copper material. The bending stiffness K bend of the elastic rod 4 is calculated by the formula:

[0049] K bend = 3EI / l 3

[0050] Among them, E is the Young's modulus of the elastic rod 4; I is the moment of inertia of the cross-section of the elastic rod 4; l is the effective length of the elastic rod 4.

[0051] To further optimize the above technical solution, the calculation formula for the Young's modulus of the elastic rod 4 is E = 131×10 9 Pa;

[0052] The calculation formula for the moment of inertia of the cross-section of the elastic rod 4 is I = πd 4 / 64, where d is the diameter of the elastic rod 4.

[0053] To further optimize the above technical solution, when the relative rotation angle between the upper variable stiffness disk 2 and the lower variable stiffness disk 5 is θ, the lateral displacement at the top of each rod is δ = θr;

[0054] where r is the radius of the lower variable stiffness disk 3.

[0055] The lateral force F generated by the elastic rod 4 is: F = K bend δ = K bend θr.

[0056] The torque T of this lateral force on the central through-hole of the lower variable stiffness disk 3 single = Fr = K bend θr 2 .

[0057] The equivalent torsional stiffness K of the root elastic rod 4 single is:

[0058] K single = T single / θ

[0059] The torsional stiffness K of the variable stiffness component is:

[0060]

[0061] In the present invention, r = 40 mm, d = 5 mm, and the variation range of l is: 50 - 100 mm. The variable range of the torsional stiffness of the variable stiffness component is: 77.2 - 617.3 Nm / rad, that is, when the system is in the no-load operation state, the torsional stiffness of the variable stiffness component is 77.2 Nm / rad, and at this time the torsional stiffness of the system is low. When the system transitions from the no-load operation state to the load operation state, the impact and vibration received are small. Therefore, it shows that the variable stiffness component has a good buffering and shock-absorbing effect; when the system is in the fully loaded state, the torsional stiffness of the variable stiffness component is 617.3 Nm / rad, and at this time the torsional stiffness of the system is high enough to meet the requirement of the grinding accuracy for the torsional stiffness of the system.

[0062] To further optimize the above technical solution, the part of the transmission shaft 21 located inside the housing 1 is a stepped shaft, which is in clearance fit with the central through hole, and the shaft shoulder 211 of the stepped shaft is used to limit the axial displacement of the lower variable stiffness disk 3.

[0063] To further optimize the above technical solution, a first annular groove 11 is formed in the inner bottom wall of the housing 1, and a first annular magnet 12 is installed in the first annular groove 11; a second annular groove 32 is formed in the upper surface of the lower variable stiffness disk 3, and a second annular magnet 33 is installed in the second annular groove 32; the same poles of the first annular magnet 12 and the second annular magnet 33 face each other.

[0064] To further optimize the above technical solution, the working end 6 is a grinding assembly, a polishing assembly or a cutting assembly.

[0065] To further optimize the above technical solution, in this embodiment, the working end 6 is a grinding assembly. The grinding assembly includes a plugging rod and a grinding tool 61. The plugging rod is fastened to the bottom end of the transmission rod 31 through a locking nut 62, and the grinding tool 61 is fixed to the bottom of the plugging rod. The plugging rod cooperates with the locking nut 62 to achieve rapid replacement of the grinding tool 61 and reduce the downtime; at the same time, different types of grinding tools (such as polishing wheels, grinding wheels) can be adapted and replaced to meet the requirements of multiple processes.

[0066] To further optimize the above technical solution, a first through hole 13 and a second through hole 14 are respectively formed in the top and bottom of the housing 1. The top end of the transmission shaft 21 passes through the first through hole 13 and extends above the housing 1, and the bottom end of the transmission rod 31 passes through the second through hole 14 and extends below the housing 1.

[0067] To further optimize the above technical solution, a deep groove ball bearing 131 is installed in the first through hole 13, and the transmission shaft 21 is fixed to the inner ring of the deep groove ball bearing 131; a bushing 141 is installed in the second through hole 14, and the bushing 141 is in clearance fit with the transmission rod 31 to enable the transmission rod 31 to rotate and move axially.

[0068] To further optimize the above technical solution, the bottom of the housing 1 is detachably connected with a bottom end cover 15 through bolts, which is convenient for installation or subsequent maintenance; the first annular groove 11 is formed in the upper surface of the bottom end cover 15.

[0069] The present invention also discloses a robot grinding device, which includes a robot body and a variable stiffness buffer and shock absorption mechanism according to any one of claims 1-6; a grinding end effector is connected to the robot body, the housing 1 is fixed to the grinding end effector, and the driving part of the grinding end effector is in transmission connection with the transmission shaft 21 extending outside the housing 1. The grinding end effector is a prior art and can refer to the patent: CN117400104A, which will not be elaborated here.

[0070] The working process of the present invention is as follows:

[0071] The transmission shaft 21 of the upper variable stiffness disk 2 of the present invention is connected to the driving part (electric spindle or pneumatic spindle) of the grinding end actuator (such as the grinding end mentioned in patent: CN117400104A), and the housing 1 is fixed on the grinding end actuator so that the housing 1 and the grinding end actuator are relatively static. When the grinding task needs to be performed, the driving part (electric spindle or pneumatic spindle) drives the upper variable stiffness disk 2 to rotate, and the upper variable stiffness disk 2 transmits the motion to the lower variable stiffness disk 3 through the elastic rod 4, and the lower variable stiffness disk 3 drives the grinding tool 61 to rotate through the transmission rod 31. When the system is in a no-load operation state, the lower variable stiffness disk 3 is at the farthest position from the upper variable stiffness disk 2 under the action of the elastic force of the spring 5 and the repulsive force of the first annular magnet 12 and the second annular magnet 33, and the elastic rod 4 has the largest effective length. At this time, the torsional stiffness of the variable stiffness assembly is the lowest. When the grinding tool 61 just contacts the workpiece to be processed, the system has very low torsional stiffness, so the system has very little impact and vibration when it transitions from the no-load operation state to the load operation state. As the grinding force increases, the spring 5 is compressed, and the lower variable stiffness disk 3 begins to approach the upper variable stiffness disk 2 until the lower variable stiffness disk 3 contacts the shoulder 211 of the stepped shaft of the upper variable stiffness disk 2, and the grinding force reaches the maximum. The force sensor at the end of the grinding will assist the grinding tool to continue grinding with this grinding force. At this time, the effective length of the elastic rod 4 is the shortest, and the torsional stiffness of the variable stiffness component reaches the maximum to meet the grinding accuracy requirements for the system torsional stiffness.

[0072] In order to reduce the impact and vibration in the transition stage from the no-load operation state to the load-bearing operation state of the system, improve the grinding quality and extend the service life of the equipment, the present invention adopts a variable stiffness component mainly composed of an upper variable stiffness disk, a lower variable stiffness disk and an elastic rod 4, which can effectively solve the above problems; and in order to increase the speed of tool replacement, a corresponding tool chuck and disassembly hole are designed on the transmission rod 31 of the lower variable stiffness disk 3 to quickly replace the tool.

[0073] Any matters not described in the present invention are applicable to the prior art.

[0074] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0075] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A variable stiffness buffering and shock absorbing mechanism, comprising a housing (1), wherein the interior of the housing (1) is hollow, and characterized in that: It also includes a variable stiffness component installed inside the housing (1), and the variable stiffness component includes: An upper variable rigidity plate (2), wherein a transmission shaft (21) is fixedly passed through the middle of the upper variable rigidity plate (2), the top end of the transmission shaft (21) passes through the top wall of the shell (1) and extends to the outside of the shell, and the bottom end of the transmission shaft (21) is located inside the shell (1); A lower variable rigidity disk (3), the lower variable rigidity disk (3) being located below the upper variable rigidity disk (2), the central through hole of the lower variable rigidity disk (3) being clearance-matched with the transmission shaft (21), and a transmission rod (31) penetrating through the bottom wall of the housing (1) being fixed to the bottom wall thereof, the transmission rod (31) having a cavity (311) inside thereof so that the bottom end of the transmission shaft (21) can be inserted into the cavity (311), and the bottom of the transmission rod (31) is detachably connected with an execution working end (6); An elastic rod (4), the top end of which is fixed on the bottom wall of the upper variable rigidity disk (2), and the bottom end of which is in clearance fit with the lower variable rigidity disk (3); a spring (5) is sleeved on the outer side of the elastic rod (4), and the two ends of the spring (5) are pressed tightly between the upper variable rigidity disk (2) and the lower variable rigidity disk (3); The execution working end (6) is subjected to force, causing the lower variable rigidity disk (3) to move axially along the transmission shaft (21) to change the effective length of the elastic rod (4) and achieve adaptive rigidity adjustment.

2. A variable stiffness buffering and shock absorbing mechanism according to claim 1, characterized in that: There are a plurality of elastic rods (4), and the plurality of elastic rods (4) are circumferentially arranged between the upper variable stiffness disk (2) and the lower variable stiffness disk (3).

3. The variable stiffness buffering and shock absorbing mechanism according to claim 1, characterized in that: The elastic rod (4) is a cylindrical rod made of beryllium copper. The bending stiffness K of the elastic rod (4) is bend The calculation formula is: <h2 style=";text-align:left;direction:ltr">K<h2 style=";text-align:left;direction:ltr"> bend <h2 style=";text-align:left;direction:ltr"> <3EI / l<h2 style=";text-align:left;direction:ltr"> 3 Wherein, E is the Young's modulus of the elastic rod (4); I is the cross-sectional moment of inertia of the elastic rod (4); and l is the effective length of the elastic rod (4).

4. A variable stiffness buffering and shock absorbing mechanism according to claim 3, characterized in that: The Young's modulus of the elastic rod (4) is calculated as E=131×10 9 Pa; The calculation formula of the cross-sectional inertia moment of the elastic rod (4) is I=πd 4 / 64, wherein d is the diameter of the elastic rod (4).

5. The variable stiffness buffering and shock absorbing mechanism according to claim 1, characterized in that: The portion of the transmission shaft (21) located inside the housing (1) is a stepped shaft, the stepped shaft is clearance-matched with the central through hole, and the shoulder (211) of the stepped shaft is used to limit the axial displacement of the lower variable stiffness disk (3).

6. The variable stiffness buffering and shock absorbing mechanism according to claim 1, characterized in that: The inner bottom wall of the shell (1) is provided with a first annular groove (11), and a first annular magnet (12) is installed in the first annular groove (11); the upper surface of the lower variable rigidity disk (3) is provided with a second annular groove (32), and a second annular magnet (33) is installed in the second annular groove (32); the first annular magnet (12) and the second annular magnet (33) are opposed to each other with the same poles.

7. The variable stiffness buffering and shock absorbing mechanism according to claim 1, characterized in that: The execution working end (6) is a grinding component, a polishing component or a cutting component.

8. The variable stiffness buffering and shock absorbing mechanism according to claim 1, characterized in that: The top and bottom of the shell (1) are respectively provided with a first through hole (13) and a second through hole (14); the top end of the transmission shaft (21) passes through the first through hole (13) and extends to the top of the shell (1); and the bottom end of the transmission rod (31) passes through the second through hole (14) and extends to the bottom of the shell (1).

9. The variable stiffness buffering and shock absorbing mechanism according to claim 8, characterized in that: A deep groove ball bearing (131) is installed in the first through hole (13), and the transmission shaft (21) is fixed to the inner ring of the deep groove ball bearing (131); a shaft sleeve (141) is installed in the second through hole (14), and the shaft sleeve (141) and the transmission rod (31) are clearance-matched, so that the transmission rod (31) can rotate and move axially.

10. A robot polishing device, characterized in that: It comprises a robot body and the variable stiffness buffering and shock absorbing mechanism as described in any one of claims 1 to 9; a grinding end effector is connected to the robot body, the shell (1) is fixed on the grinding end effector, and the driving part of the grinding end effector is connected to the transmission shaft (21) extending to the outside of the shell (1).

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