Magnetorheological damping flexible constant force polishing and vibration suppression mechanism

Abstract

The application is a kind of magnetic rheological damping flexible constant force polishing and vibration suppression mechanism, comprising: passive flexible component, fixed plate flange, quick connector, coil, insulating sheet, rubber cover plate, polishing head. Wherein the passive flexible component comprises: inner shell, outer shell, positive stiffness characteristic mechanism, negative stiffness characteristic mechanism, grid plate, the application is installed at the end of industrial robot to realize flexible polishing work, based on the characteristics of positive and negative stiffness characteristic mechanism to realize constant force polishing under certain position deviation, by changing the current size in the coil and then changing the viscosity of magnetic rheological fluid, and then changing the size of damping force, suppressing vibration and reducing force fluctuation, controlling the polishing force in the desired range, improving the stability of polishing force, not only ensuring to prevent workpiece, end effector and polishing environment from being damaged, but also improving the surface polishing quality of workpiece and improving production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of industrial robot technology, specifically relating to a magnetorheological damping compliant constant force grinding and vibration suppression mechanism. Background Technology

[0002] In modern manufacturing, surface grinding of workpieces is a crucial process, as its quality directly affects product performance, appearance, and subsequent processing. With the continuous development of industrial technology, the requirements for the precision and consistency of workpiece surface grinding are increasing.

[0003] Traditional polishing processes typically rely on manual operation of polishing tools, which has several drawbacks. Firstly, manual polishing struggles to maintain consistent polishing force over extended periods. Operators are prone to fatigue during polishing, causing fluctuations in the force applied to the workpiece. This results in inconsistent surface quality, including uneven polishing depth and surface scratches, severely impacting product yield. For instance, in polishing the housings of precision instruments, even minute force variations can cause visible defects on the surface, lowering the product's quality.

[0004] On the other hand, manual grinding struggles to precisely adapt to the grinding angles and forces required for different curved surfaces and sharp edges when dealing with workpieces with complex shapes. For some aero-engine blades and automotive parts with complex geometries, manual grinding is not only inefficient but also fails to meet high-precision machining requirements, increasing production costs and processing cycles. To overcome the limitations of manual grinding, automated mechanical grinding equipment has emerged. Early automated grinding devices mostly used rigid structures, directly controlling the movement of the grinding tool through drive components such as motors and cylinders. However, these rigid grinding systems still have problems in practical applications. Since the workpiece surface cannot be completely flat, if a tiny protrusion or depression is encountered during grinding, the rigid structure cannot adaptively adjust, resulting in instantaneous impact force. This can easily damage the grinding tool and cause defects such as indentations and chipping on the workpiece surface, failing to achieve high-precision, smooth grinding. With further research, positive and negative stiffness characteristic mechanisms have been applied to grinding mechanisms. This mechanism possesses high static stiffness, meaning it can maintain structural stability under static loads, ensuring the system's positioning accuracy, and can automatically adjust its mechanical properties according to changes in the external environment. When subjected to forces of varying amplitudes and frequencies, the positive and negative stiffness components within the mechanism cooperate to dynamically alter the stiffness distribution, adapting to changes in external forces. However, due to the complexity of designing and modeling positive and negative stiffness characteristic mechanisms, as well as limitations in the materials used, their vibration suppression effect against grinding forces is limited. Summary of the Invention

[0005] To address the aforementioned problems, this invention specifically proposes a magnetorheological damping compliant constant force grinding and vibration suppression mechanism.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a magnetorheological damping compliant constant force grinding and vibration suppression mechanism, including: a passive compliant component (1), a fixed plate flange (2), a quick-connect coupling (3), a coil (4), an insulating sheet (5), an upper rubber cover plate (6), a lower rubber cover plate (7), and a grinding head (8). The passive compliant component includes: an inner shell (9), an outer shell (10), a positive stiffness characteristic mechanism (11), a negative stiffness characteristic mechanism (12), and a grid plate (13). The inner and outer shells (10) are hollow cylindrical structures. The four positive stiffness characteristic mechanisms (11), the four negative stiffness characteristic mechanisms (12), and the eight grid plates (13) are evenly distributed in the lower half of the ring between the inner shell (9) and the outer shell (10). When faced with vibration, the individual positive stiffness mechanism can only provide simple resistance, while the negative stiffness mechanism can buffer energy to a certain extent, but each has its limitations. The combination of the two can fully utilize the energy storage characteristics of positive stiffness and the energy dissipation characteristics of negative stiffness to form a complementary relationship. The upper rubber cover plate (6) and the lower rubber cover plate (7) seal the lower half of the ring, which is filled with magnetorheological fluid. Three coils (4) and two insulating sheets (5) are alternately sleeved on the outside of the outer shell (10). During the grinding process, when the grinding head contacts the uneven parts of the workpiece surface, such as protrusions or depressions, the coils installed on the outside of the outer shell will quickly adjust the magnetic field strength according to the displacement or force information fed back by the sensor. The magnetorheological fluid then responds and changes its own stiffness to adapt to the changes in the workpiece surface, absorbs the impact force generated by the surface undulation, and ensures that the force applied to the workpiece by the grinding tool remains relatively constant, avoiding damage to the workpiece surface due to sudden changes in force, thereby achieving high-precision compliant grinding. The grinding head (8) is installed on the inner surface of the inner shell (9), the fixed plate flange (2) is connected to the upper end of the passive compliant component (1), and the quick-connect joint (3) is connected to the fixed plate flange (2).

[0007] Preferably, the inner shell (9) is cylindrical in shape and has a U-shaped groove at the top. The grinding tool can be fixed through the U-shaped groove to prevent the grinding tool from twisting due to vibration and grinding force, which would affect the grinding efficiency.

[0008] Preferably, there are four positive stiffness characteristic mechanisms (11), all of which are in the same horizontal plane and are evenly distributed in the lower half of the cylindrical surface of the inner shell (9).

[0009] Preferably, there are 4 negative stiffness characteristic mechanisms (12), all of which are in the same horizontal plane. Each negative stiffness characteristic mechanism (12) and a positive stiffness characteristic mechanism (11) are located on the same generatrix, and the negative stiffness characteristic mechanism (12) is located above the positive stiffness characteristic mechanism (11).

[0010] Preferably, the upper and lower end faces of the outer casing (10) are provided with threaded holes for fastening connection;

[0011] Preferably, the eight grid plates (13) are evenly distributed in the annular space between the inner shell (9) and the outer shell (10), and their two ends are connected to the inner shell (9) and the outer shell (10) respectively.

[0012] Preferably, the lower half of the outer casing (10) is fitted with a coil (4).

[0013] Preferably, the lower half of the ring where the positive characteristic stiffness mechanism (11), the negative characteristic stiffness mechanism (12) and the grid plate (13) are located is sealed by the upper rubber cover plate (6) and the lower rubber cover plate (7), and the interior is filled with magnetorheological fluid.

[0014] Preferably, the area covered by the coil (4) is exactly the area filled with magnetorheological fluid, so that the magnetic field generated by the coil (4) can be fully utilized.

[0015] The beneficial effects of this invention are:

[0016] This invention does not employ a single-mechanism design, but rather a stiffness combination method, combining negative and positive stiffness. By compensating for Young's modulus through the stiffness combination mechanism, it eliminates the need for materials with low Young's modulus and high strength-to-modulus ratio (materials that are not readily available in practice, and manufacturing with special materials may make it difficult to form specific shapes), thus reducing the overall structural requirements for material properties.

[0017] This invention can better suppress vibrations generated during grinding without affecting the grinding performance of the end effector, and there is no overall conflict between sensitivity and performance.

[0018] The compliant mechanism of this invention has better stability and overload capacity than other independent compliant mechanisms, meaning that the designed compliant mechanism is more robust and durable.

[0019] The cylindrical structure of the present invention is suitable for rotational motion, which enables the compliant mechanism to maintain uniform force during motion and allows the centroids of all structures of the end effector to be on the same axis, so that each mechanism can maintain the same motion state.

[0020] In the combination of negative stiffness characteristic mechanism (12) and positive stiffness characteristic mechanism (11), the present invention further adopts the method of filling the passive compliant component (1) with magnetorheological fluid and wrapping the coil (4) on the surface of the outer shell (10). By utilizing the characteristic that the magnetorheological fluid will rapidly change its stiffness when it receives this field, the constant force control of the end effector is further enhanced. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a magnetorheological damping compliant constant force grinding and vibration suppression mechanism of the present invention.

[0022] Figure 2 This is a schematic diagram of the overall structure and a half-sectional view of a magnetorheological damping compliant constant force grinding and vibration suppression mechanism of the present invention.

[0023] Figure 3 This is a schematic diagram of the overall structure of the passive compliant component of a magnetorheological damping compliant constant force grinding and vibration suppression mechanism of the present invention.

[0024] Figure 4 This is a schematic diagram of the internal structure of the passive compliant component of the magnetorheological damping compliant constant force grinding and vibration suppression mechanism of the present invention after removing the outer shell.

[0025] The attached figures are labeled as follows:

[0026] 1. Passive compliant assembly; 2. Fixed plate flange; 3. Quick-connect coupling; 4. Coil; 5. Insulating sheet; 6. Upper rubber cover; 7. Lower rubber cover; 8. Grinding head; 9. Inner shell; 10. Outer shell; 11. Positive stiffness characteristic mechanism; 12. Negative stiffness characteristic mechanism; 13. Grating plate; Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention are shown in the drawings, and not the entire structure.

[0028] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them; moreover, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature; "below," "under," and "below" of the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] like Figure 1 As shown, a magnetorheological damping compliant constant force grinding and vibration suppression mechanism includes: a passive compliant component (1), a fixed plate flange (2), a quick-connect coupling (3), a coil (4), an insulating sheet (5), an upper rubber cover plate (6), a lower rubber cover plate (7), and a grinding head (8). The passive compliant component includes: an inner shell (9), an outer shell (10), a positive stiffness characteristic mechanism (11), a negative stiffness characteristic mechanism (12), and a grid plate (13). The inner and outer shells (10) are hollow cylindrical structures. The four positive stiffness characteristic mechanisms (11), the four negative stiffness characteristic mechanisms (12), and the eight grid plates (13) are evenly distributed in the lower half of the ring between the inner shell (9) and the outer shell (10). When faced with vibration, the individual positive stiffness mechanism can only provide simple resistance, while the negative stiffness mechanism can buffer energy to a certain extent, but each has its limitations. The combination of the two can fully utilize the energy storage characteristics of positive stiffness and the energy dissipation characteristics of negative stiffness to form a complementary relationship. The upper rubber cover plate (6) and the lower rubber cover plate (7) seal the lower half of the ring, which is filled with magnetorheological fluid. Three coils (4) and two insulating sheets (5) are alternately sleeved on the outside of the outer shell (10). During the grinding process, when the grinding head contacts the uneven parts of the workpiece surface, such as protrusions or depressions, the coils installed on the outside of the outer shell will quickly adjust the magnetic field strength according to the displacement or force information fed back by the sensor. The magnetorheological fluid then responds and changes its own stiffness to adapt to the changes in the workpiece surface, absorbs the impact force generated by the surface undulation, and ensures that the force applied to the workpiece by the grinding tool remains relatively constant, avoiding damage to the workpiece surface due to sudden changes in force, thereby achieving high-precision compliant grinding. The grinding head (8) is installed on the inner surface of the inner shell (9), the fixed plate flange (2) is connected to the upper end of the passive compliant component (1), and the quick-connect joint (3) is connected to the fixed plate flange (2).

[0031] like Figure 2As shown, the grinding head (8) is installed inside the cylindrical surface of the passive compliant component (1). The upper rubber cover (6) is installed between the outer shell (10) and the inner shell (9) in a ring, and its shape and size are just right to completely seal the ring. The lower rubber cover (7) is installed below the passive compliant component (1). The upper rubber cover (6) and the lower rubber cover (7) seal the annular space between the outer shell (10) and the inner shell (9), which plays the role of sealing the magnetorheological fluid. There are 4 negative stiffness characteristic mechanisms (12). All 4 mechanisms are in the same horizontal plane. Each negative stiffness characteristic mechanism (12) and a positive stiffness characteristic mechanism (11) are located on the same generatrix, and the negative stiffness characteristic mechanism (12) is located above the positive stiffness characteristic mechanism (11). The negative stiffness and positive stiffness are combined by using the stiffness combination method. By compensating for Young's modulus through a stiffness combination mechanism, it is not necessary to use materials with low Young's modulus and high strength-to-modulus ratio (these materials are not easy to obtain in practice, and it may be difficult to form specific shapes using special materials), thus reducing the overall structural requirements for material properties.

[0032] like Figure 4 As shown, there are 4 positive stiffness characteristic mechanisms (11), all of which are in the same horizontal plane and are evenly distributed in the lower half of the cylindrical surface of the inner shell. There are 4 negative stiffness characteristic mechanisms (12), all of which are in the same horizontal plane. Each negative stiffness characteristic mechanism (12) and a positive stiffness characteristic mechanism (11) are located on the same generatrix, and the negative stiffness characteristic mechanism (12) is located above the positive stiffness characteristic mechanism (11). Eight grid plates (13) are evenly distributed in the annular space between the inner and outer shells, and their two ends are connected to the inner shell (9) and the outer shell (10) respectively. When the magnetorheological fluid is not subjected to the magnetic field of the coil (4), the magnetorheological fluid can flow smoothly between the grid plates (13). When the magnetorheological fluid is subjected to the magnetic field of the coil (4), the magnetorheological fluid changes its own stiffness and is not easy to flow between the grid plates (13), thereby absorbing the impact force generated by the surface undulation, ensuring that the force applied to the workpiece by the grinding tool remains relatively constant, avoiding damage to the workpiece surface due to sudden changes in force, thereby achieving high-precision smooth grinding.

Claims

1. A magnetorheological damping compliant constant force grinding and vibration suppression mechanism, characterized in that: The passive compliance assembly includes (1), a fixed plate flange (2), a quick-connect coupling (3), a coil (4), an insulating sheet (5), an upper rubber cover (6), a lower rubber cover (7), and a grinding head (8). The passive compliance assembly includes: an inner shell (9), an outer shell (10), a positive stiffness characteristic mechanism (11), a negative stiffness characteristic mechanism (12), and a grid plate (13). The inner shell (9) and the outer shell (10) are hollow cylindrical structures, and there are 4 positive stiffness characteristic mechanisms (11) and 4 negative stiffness characteristic mechanisms. (12) and 8 grid plates (13) are evenly distributed in the lower half of the ring between the inner shell (9) and the outer shell (10); the upper rubber cover plate (6) and the lower rubber cover plate (7) seal the lower half of the ring, which is filled with magnetorheological fluid. Three coils (4) and two insulating sheets (5) are alternately sleeved on the outside of the outer shell (10). The magnetic field strength will be quickly adjusted according to the displacement or force information fed back by the sensor. The magnetorheological fluid will then respond and change its own stiffness to adapt to the changes in the workpiece surface and absorb the stress caused by the surface undulation. The impact force ensures that the force applied by the grinding tool to the workpiece remains relatively constant; the grinding head (8) is installed on the inner surface of the inner shell (9), the fixed plate flange (2) is connected to the upper end of the passive compliant component (1), and the quick-connect coupling (3) is connected to the fixed plate flange (2); there are 4 positive stiffness characteristic mechanisms (11), all 4 mechanisms are in the same horizontal plane and are evenly distributed in the lower half of the cylindrical surface of the inner shell (9), and the negative stiffness characteristic mechanisms (12) are all in the same horizontal plane, one negative stiffness characteristic Mechanism (12) and a positive stiffness characteristic mechanism (11) are located on the same generatrix, and the negative stiffness characteristic mechanism (12) is located above the positive stiffness characteristic mechanism (11); eight grid plates (13) are evenly distributed in the annular space between the inner and outer shells, and their two ends are connected to the inner shell (9) and the outer shell (10) respectively; the lower half of the annulus where the positive stiffness characteristic mechanism (11), the negative stiffness characteristic mechanism (12) and the grid plates (13) are located is sealed by a lower rubber cover plate (7), and the interior is filled with magnetorheological fluid.

2. The magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The inner shell (9) is cylindrical in shape and has a U-shaped groove at the top, through which grinding tools can be fixed.

3. The magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The outer casing (10) has threaded holes on its upper and lower end faces for fastening connections.

4. The magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The lower half of the outer shell (10) is fitted with a coil (4).

5. The magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The area covered by the coil (4) is exactly the area filled with magnetorheological fluid.

Images