Magneto-rheological damping smooth constant-force grinding and vibration suppression mechanism

Abstract

The invention relates to a magneto-rheological damping compliant constant-force polishing and vibration suppression mechanism which comprises a passive compliant assembly, a fixing plate flange, a quick-change connector, a coil, an insulating sheet, a rubber cover plate and a polishing head. Wherein the passive flexible assembly comprises an inner shell, an outer shell, a positive stiffness characteristic mechanism, a negative stiffness characteristic mechanism and a grating plate, the passive flexible assembly is installed at the tail end of the industrial robot to achieve flexible grinding operation, and constant-force grinding under certain position deviation is achieved based on the characteristics of the positive stiffness characteristic mechanism and the negative stiffness characteristic mechanism; the viscosity of the magnetorheological fluid is changed by changing the current in the coil, then the damping force is changed, vibration is restrained, force fluctuation is reduced, the grinding force is controlled within the expected range, the stability of the grinding force is improved, it is guaranteed that a workpiece, an end executor and the grinding environment are prevented from being damaged, the surface grinding quality of the workpiece is improved, and the grinding efficiency is improved. And the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial robots, and in particular relates to a magnetorheological damping compliant constant force grinding and vibration suppression mechanism. Background Art

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

[0003] Traditional grinding processes usually rely on manual operation of grinding tools, which has many disadvantages. On the one hand, manual grinding is difficult to ensure long-term and stable grinding force output. Operators are prone to fatigue during the grinding process, which causes fluctuations in the force applied to the workpiece, resulting in uneven surface quality of the workpiece, inconsistent grinding depth, uneven surface scratches, and other problems, which seriously affect the product yield. For example, in the grinding of the housing of precision instruments and meters, slight changes in force may cause visible defects on the surface of the housing, reducing the grade of the product.

[0004] On the other hand, when facing workpieces with complex shapes, manual grinding is difficult to accurately adapt to the grinding angles and forces required for different curved surfaces and corners. For some aircraft engine blades and automobile parts with complex geometric shapes, manual grinding is not only inefficient, but also difficult to meet the high-precision processing requirements, increasing production costs and processing cycles. In order to overcome the limitations of manual grinding, mechanical automatic grinding equipment came into being. Early automatic grinding devices mostly adopted rigid structures, and directly controlled the movement of grinding tools through driving elements such as motors and cylinders. However, this type of rigid grinding system still has problems in practical applications. Since the surface of the workpiece cannot be completely flat, once a small protrusion or depression on the surface of the workpiece is encountered during the grinding process, the rigid structure cannot be adjusted adaptively, and an impact force will be generated instantly, which is not only easy to damage the mold, but also may cause defects such as indentation and edge collapse on the surface of the workpiece, and high-precision smooth grinding cannot be achieved. With the deepening of research, positive and negative stiffness characteristic mechanisms are applied to grinding mechanisms. The mechanism has high static stiffness, which means that when subjected to static loads, it can maintain the stability of the structure, ensure the positioning accuracy of the system, and automatically adjust its own mechanical properties according to changes in the external environment. When subjected to forces of different amplitudes and frequencies, the positive and negative stiffness components inside the mechanism work together to dynamically change the stiffness distribution to adapt to changes in external forces. However, due to the complexity of the design and modeling of the positive and negative stiffness characteristic mechanism and the limitations of its own materials, its vibration suppression effect on grinding forces is limited. Summary of the invention

[0005] In order to solve the above problems, the present 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 the technical problem is: a magnetorheological damping compliant constant force grinding and vibration suppression mechanism, comprising: a passive compliant component (1), a fixed plate flange (2), a quick-change joint (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 comprises: 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. Four positive stiffness characteristic mechanisms (11), four negative stiffness characteristic mechanisms (12) and 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 facing vibration, a single positive stiffness mechanism can often only provide a simple resistance effect, and although the negative stiffness mechanism can buffer energy to a certain extent, each has its own limitations. After the two are combined, the energy storage characteristics of positive stiffness and the energy consumption characteristics of negative stiffness can be fully utilized 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, and the interior 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 part of the workpiece surface, such as convex or concave, the coil 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 immediately responds and changes its own stiffness to adapt to the changes in the workpiece surface, absorbs the impact force generated by the surface fluctuations, ensures that the force applied by the grinding tool on the workpiece remains relatively constant, and avoids damage to the workpiece surface due to sudden changes in force, thereby achieving high-precision flexible 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 flexible component (1), and the quick-change connector (3) is connected to the fixed plate flange (2).

[0007] Preferably, the inner shell (9) is cylindrical as a whole, and a U-shaped groove is provided at the upper end, through which the grinding tool can be fixed to prevent the grinding tool from twisting due to vibration and grinding force, thereby affecting the grinding efficiency.

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

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

[0010] Preferably, threaded holes are provided on the upper and lower end surfaces of the outer shell (10) 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 the two ends are connected to the inner shell (9) and the outer shell (10) respectively.

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

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

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

[0015] The beneficial effects of the present invention are:

[0016] The present invention does not adopt a single mechanism design, but adopts a stiffness combination method to combine negative stiffness and positive stiffness. By using the stiffness combination mechanism to compensate for the Young's modulus, 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 a specific shape using special materials), thereby reducing the requirements of the overall structure on material performance.

[0017] The present invention can better suppress the vibration generated during grinding without affecting the grinding performance of the end effector, and generally there is no conflict between sensitivity and performance.

[0018] The stability and overload bearing capacity of the compliant mechanism of the present invention are superior to those of other independent compliant mechanisms, that is, the designed compliant mechanism is more solid and durable.

[0019] The cylindrical structure of the present invention is suitable for rotational motion, can keep the compliant mechanism under uniform force during motion, and can make the centers of mass of all structures of the end effector on the same axis, so that each mechanism can maintain the same motion state.

[0020] The present invention combines a negative stiffness characteristic mechanism (12) and a positive stiffness characteristic mechanism (11), and further adopts a method of filling a magnetorheological fluid in a passive compliance component (1) and sleeve a coil (4) on the surface of an outer shell (10). The magnetorheological fluid can rapidly change its own stiffness when receiving the field, so as to further strengthen the constant force control of the end actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It 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 It is an overall structural schematic diagram and a half-section view of a magnetorheological damping compliant constant force grinding and vibration suppression mechanism of the present invention.

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

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

[0025] The reference numerals in the figures are as follows:

[0026] 1. Passive compliance component; 2. Fixed plate flange; 3. Quick-change connector; 4. Coil; 5. Insulation 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. Grid plate; DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments. It will be understood that the specific embodiments described herein are only used to explain the present invention rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention rather than all structures are shown in the accompanying drawings.

[0028] In the description of the present invention, unless otherwise clearly stipulated and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the present invention, unless otherwise clearly stipulated and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them; furthermore, a first feature being "above", "above" and "above" the second feature includes the first feature being directly above and diagonally above the second feature, or simply means that the first feature is higher in level than the second feature; a first feature being "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature is lower in level than the second feature.

[0030] like Figure 1 As shown, a magnetorheological damping compliant constant force grinding and vibration suppression mechanism comprises: a magnetorheological damping compliant constant force grinding and vibration suppression mechanism comprises: a passive compliant component (1), a fixed plate flange (2), a quick-change joint (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 comprises: 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. Four positive stiffness characteristic mechanisms (11), four negative stiffness characteristic mechanisms (12) and 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 facing vibration, a single positive stiffness mechanism can often only provide a simple resistance effect, and although the negative stiffness mechanism can buffer energy to a certain extent, each has its own limitations. After the two are combined, the energy storage characteristics of positive stiffness and the energy consumption characteristics of negative stiffness can be fully utilized 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, and the interior 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 part of the workpiece surface, such as convex or concave, the coil 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 immediately responds and changes its own stiffness to adapt to the changes in the workpiece surface, absorbs the impact force generated by the surface fluctuations, ensures that the force applied by the grinding tool on the workpiece remains relatively constant, and avoids damage to the workpiece surface due to sudden changes in force, thereby achieving high-precision flexible 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 flexible component (1), and the quick-change connector (3) is connected to the fixed plate flange (2).

[0031] like Figure 2As shown, the grinding head (8) device is installed in the cylindrical surface of the passive compliance component (1). The upper rubber cover plate (6) is installed between the circular ring between the outer shell (10) and the inner shell (9), and its shape and size just seal the circular ring. The lower rubber cover plate (7) is installed below the passive compliance component (1). The upper rubber cover plate (6) and the lower rubber cover plate (7) seal the circular ring space between the outer shell (10) and the inner shell (9), playing the role of sealing the magnetorheological fluid; there are 4 negative stiffness characteristic mechanisms (12), and the 4 mechanisms are all in the same horizontal plane. Each negative stiffness characteristic mechanism (12) and a positive stiffness characteristic mechanism (11) are located on the same busbar, and the negative stiffness characteristic mechanism (12) is located above the positive stiffness characteristic mechanism (11). The stiffness combination method is adopted to combine the negative stiffness and the positive stiffness. By compensating the Young's modulus through the stiffness combination mechanism, there is no need 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 a specific shape using special materials), thereby reducing the requirements of the overall structure on material properties.

[0032] like Figure 4 As shown, 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. There are four 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 busbar, 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 the two ends are connected to the inner shell (9) and the outer shell (10) respectively. When the magnetorheological fluid is not affected by the magnetic field of the coil (4), the magnetorheological fluid can flow smoothly between the grid plates (13). When the magnetorheological fluid is affected by the magnetic field of the coil (4), the magnetorheological fluid changes its own rigidity and is not easy to flow between the grid plates (13), thereby absorbing the impact force generated by the surface fluctuations, ensuring that the force applied by the grinding tool on the workpiece remains relatively constant, avoiding damage to the workpiece surface due to sudden changes in force, and thus achieving high-precision smooth grinding.

Claims

1. A magnetorheological damping compliant constant force grinding and vibration suppression mechanism characterized by: include: Passive compliance component (1), fixed plate flange (2), quick-change connector (3), coil (4), insulating sheet (5), upper rubber cover plate (6), lower rubber cover plate (7), grinding head (8). The passive compliance component includes: inner shell (9), outer shell (10), positive stiffness characteristic mechanism (11), negative stiffness characteristic mechanism (12), grid plate (13), the inner and outer shells (10) are hollow cylindrical structures, and 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). The lower half of the circular ring is sealed by an upper rubber cover plate (6) and a lower rubber cover plate (7), and a magnetorheological fluid is filled inside. Three coils (4) and two insulating sheets (5) are alternately sleeved on the outside of the outer shell (10), a grinding head (8) is installed on the inner surface of the inner shell (9), a fixed plate flange (2) is connected to the upper end of the passive compliance component (1), and a quick-change joint (3) is connected to the fixed plate flange (2).

2. A magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The inner shell (9) is cylindrical as a whole, and a U-shaped groove is provided at the upper end, through which a grinding tool can be fixed.

3. A magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: There are four positive stiffness characteristic mechanisms (11), all of which are in the same horizontal plane and evenly distributed in the lower half of the cylindrical surface of the inner shell.

4. A magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: There are four negative stiffness characteristic mechanisms (12), all of which are located in the same horizontal plane. Each negative stiffness characteristic mechanism (12) and a positive stiffness characteristic mechanism (11) are located on the same busbar, and the negative stiffness characteristic mechanism (12) is located above the positive stiffness characteristic mechanism (11).

5. A magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The upper and lower end surfaces of the outer shell (10) are provided with threaded holes for fastening connection.

6. A magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The eight grid plates (13) are evenly distributed in the annular space between the inner and outer shells, and the two ends are respectively connected to the inner shell (9) and the outer shell (10).

7. A 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 covered with a coil (4).

8. The magnetorheological damping compliant constant force grinding and vibration suppression mechanism according to claim 1, characterized in that: The lower half of the circular ring where the positive characteristic stiffness mechanism (11), the negative stiffness characteristic mechanism (12) and the grid plate (13) are located is sealed by a lower rubber cover plate (7) and is filled with magnetorheological fluid.

9. 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