Curved surface self-adaptive flexible grinding device and grinding method thereof

Abstract

The curved surface self-adaptive flexible grinding device comprises flexible grinding heads, a grinding machine connecting cover and an adjusting connecting piece, the flexible grinding heads are arranged at the cover opening of the grinding machine connecting cover in a spaced mode, and a central stand column is arranged in the grinding machine connecting cover along the central axis; the center stand column extends to a cover opening of the grinding machine connecting cover to be hinged to the flexible grinding head. The multiple adjusting connecting pieces are connected between the flexible grinding head and the grinding machine connecting cover, and after the side, away from the grinding machine connecting cover, of the flexible grinding head makes contact with the ground face, downward pressure applied to the grinding machine connecting cover enables the flexible grinding head to be attached to the ground face in a self-adaptive mode. The multiple adjusting connecting pieces are matched with one another to transmit stable torque in the grinding process, and the flexible grinding head is driven to synchronously rotate along with the grinding machine connecting cover. By arranging the air bag type flexible grinding head, self-adaptive attachment of the grinding head to the curved surface is achieved; through linkage of the detection module and the pressure control module, constant control over the polishing contact pressure is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of polishing and grinding equipment, and more specifically, it is a flexible grinding device and grinding method that adapts to curved surfaces. Background Technology

[0002] Polishing, as the final crucial step in curved surface manufacturing, directly determines the final quality and lifespan of the workpiece. Airbag polishing, as an emerging deterministic polishing process, exhibits unique advantages in free-form surface machining due to the excellent fit between the polishing head and the curved surface. However, existing airbag polishing technologies still have many shortcomings, making it difficult to meet the demands of high-precision machining. For example, while the polishing heads of existing devices possess a certain degree of flexibility, they lack the active deformation capability to adapt to the curvature of the surface. When facing complex curved surfaces with varying curvatures, it is difficult to maintain a perfect fit, easily leading to localized missed or over-polishing issues. Furthermore, the pressure control in existing technologies is mostly static preset mode, unable to dynamically adjust according to real-time changes in surface curvature and polishing depth during the polishing process. When the workpiece has dimensional errors or machine vibration occurs, the polishing contact force deviates from the ideal range, thus affecting the workpiece surface roughness and polishing accuracy. In addition, the connection structure of existing grinding devices lacks effective buffering and torque transmission optimization design. The instantaneous impact generated during the grinding process cannot be effectively absorbed, which not only damages the workpiece surface but also reduces the service life of the grinding media. Furthermore, the grinding head is difficult to rotate smoothly and synchronously with the host machine, which further restricts the improvement of polishing efficiency and quality. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a flexible grinding device and grinding method with surface self-adaptation. By setting an airbag-type flexible grinding head, the grinding head can achieve adaptive fitting to the curved surface; by linking the detection module and the pressure control module, the constant control of the grinding contact pressure can be achieved; and by using an electrically controlled telescopic adjustment connector and a spring buffer structure, stable torque transmission and instantaneous impact absorption can be achieved.

[0004] Technical Solution: To achieve the above objectives, the present invention provides a flexible grinding device with adaptive curved surface, comprising a flexible grinding head, a grinding machine connecting cover, and adjusting connectors. The flexible grinding head is spaced apart from the opening of the grinding machine connecting cover. A central column is arranged along the central axis inside the grinding machine connecting cover, and one end of the central column extends to the opening of the grinding machine connecting cover and is hinged to the center of the flexible grinding head. A plurality of adjusting connectors are connected between the flexible grinding head and the grinding machine connecting cover. When the side of the flexible grinding head away from the grinding machine connecting cover contacts the surface to be ground, the downward pressure applied to the grinding machine connecting cover is transmitted to the flexible grinding head through the central column, causing the flexible grinding head to adaptively conform to the surface to be ground. The plurality of adjusting connectors cooperate with each other to transmit a stable torque during the grinding process, driving the flexible grinding head to rotate synchronously with the grinding machine connecting cover.

[0005] Furthermore, the bottom of the grinding machine connecting cover forms a rigid first connecting platform, and a grinding machine connecting structure is provided on the outside of the first connecting platform. The grinding machine connecting cover is detachably connected to the grinding machine body through the grinding machine connecting structure. The central column extends integrally along the central axis of the inner side of the first connecting platform, and the central column is coaxial with the grinding machine connecting structure.

[0006] Furthermore, the flexible grinding head has a sealed airbag structure, and its outer wall surface away from the grinding machine connecting cover is a flexible grinding surface. Grinding media is detachably attached to the outer surface of the flexible grinding surface. The side of the flexible grinding head near the grinding machine connecting cover is a second connecting platform. The end of the central column away from the first connecting platform is hinged to the center of the second connecting platform through a ball joint. Several adjusting connectors are arranged between the central column and the side wall of the grinding machine connecting cover, and the two ends of each adjusting connector are respectively hinged to the side of the first connecting platform and the second connecting platform that are close to each other.

[0007] Furthermore, it also includes a pressure control module, which includes an air source structure, a venting structure, and a controller. The air source structure and the venting structure are both sealed and connected to the sealed cavity inside the flexible grinding head 1 through the second connecting platform. The controller is connected to the air source structure and the venting structure respectively, and can control the air source structure and the venting structure to inflate or deflate the sealed cavity, thereby keeping the actual contact pressure between the flexible grinding head and the surface being ground constant.

[0008] Furthermore, it also includes a detection module, which is located on the outer side of the side wall of the grinding machine connecting cover. The detection module can detect the radius of curvature and grinding depth of the surface being ground in real time. The detection module is electrically connected to the controller, which can control the air source structure and the air release structure to inflate or deflate the sealed cavity according to the detection results of the detection module.

[0009] Furthermore, the second connecting platform is a deformable metal plate externally connected to the flexible grinding head; each of the adjusting connecting components includes an electrically controlled telescopic structure and an external spring. The telescopic end of the electrically controlled telescopic structure is hinged to the ball joint of the first connecting platform, and the fixed end is hinged to the ball joint of the second connecting platform. The electrically controlled telescopic structure is also signal-connected to the controller. One end of the external spring is connected to the telescopic end of the electrically controlled telescopic structure, and the other end is connected to the outer wall of the fixed end of the electrically controlled telescopic structure. When the controller controls the air source structure and the air release structure to inflate or deflate the sealed cavity, the controller synchronously controls each electrically controlled telescopic structure to extend and retract, thereby causing the second connecting platform to deform synchronously with the flexible grinding head. The cooperation between each electrically controlled telescopic structure and the second connecting platform allows the flexible grinding surface of the flexible grinding head to completely fit with the surface being ground. The external spring absorbs the instantaneous impact during the grinding process.

[0010] Furthermore, a grinding method using a surface-adaptive flexible grinding device includes the following steps:

[0011] Step 1: Apply the polishing media to the flexible polishing surface of the flexible polishing head, and assemble and connect the flexible polishing device to the main body of the polishing machine through the polishing machine connection structure;

[0012] Step 2: Start the detection module, which detects the radius of curvature R of the surface being polished and transmits the detection data to the controller;

[0013] Step 3: Based on Step 2, the controller controls the air source structure and the air release structure to inflate or deflate the sealed cavity according to the detection results of the detection module, thereby adjusting the pressure of the sealed cavity inside the flexible grinding head.

[0014] Step 4: While performing Step 3, the controller synchronously controls the electronically controlled telescopic structure in each adjusting connector to extend and retract, so that the second connecting platform deforms accordingly with the deformation of the flexible grinding head.

[0015] Step 5: Start the main body of the grinder. The downward pressure applied by the grinder is transmitted to the flexible grinding head through the central column. The flexible grinding surface of the flexible grinding head is completely in contact with the surface to be ground under the combined action of the second connecting platform, each adjusting connector and the central column. The flexible grinding head rotates synchronously with the grinder connecting cover under the action of each adjusting connector, thereby grinding the surface to be ground.

[0016] Step Six: During the polishing process, the downward pressure applied by the polishing machine remains constant. The detection module detects and feeds back the changes in the radius of curvature R and polishing depth h of the polished surface to the controller in real time. The controller performs the adjustment operations described in Steps Three and Four in real time based on the detection results of the detection module, thereby adjusting the airbag pressure and the extension and retraction of the connecting parts in a timely manner to ensure that the flexible polishing surface of the flexible polishing head is always in complete contact with the polished surface during the polishing process and that the contact pressure during polishing is constant.

[0017] Beneficial Effects: Compared with the prior art, the flexible grinding device and grinding method of the present invention with adaptive surface grinding has the following beneficial effects: By adopting a flexible grinding head composed of a sealed airbag and a second connecting platform made of external deformable metal, the flexible grinding head can adaptively deform according to the curvature change of the surface being ground, ensuring complete contact between the flexible grinding surface and the workpiece surface, and avoiding missed grinding and local over-grinding; by setting a detection module to acquire the surface curvature radius and grinding depth data in real time, and coordinating with the controller to link the air source structure and the air release structure, the internal pressure of the flexible grinding head can be dynamically adjusted to ensure constant contact pressure during grinding, thereby improving grinding accuracy and consistency. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of a flexible grinding device with surface adaptation according to the present invention. Detailed Implementation

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] like Figure 1As shown, a flexible polishing device with adaptive curved surface includes a flexible polishing head 1, a polishing machine connecting cover 2, and adjusting connectors 6. The flexible polishing head 1 is spaced apart from the opening of the polishing machine connecting cover 2. A central column 7 is arranged along the central axis inside the polishing machine connecting cover 2, and one end of the central column 7 extends to the opening of the polishing machine connecting cover 2 and is hinged to the center of the flexible polishing head 1. Several adjusting connectors 6 are connected between the flexible polishing head 1 and the polishing machine connecting cover 2. When the side of the flexible polishing head 1 away from the polishing machine connecting cover 2 contacts the surface to be polished, the downward pressure applied to the polishing machine connecting cover 2 is transmitted to the flexible polishing head 1 through the central column 7, so that the flexible polishing head 1 adaptively conforms to the surface to be polished. The several adjusting connectors 6 cooperate with each other to transmit a stable torque during the polishing process, driving the flexible polishing head 1 to rotate synchronously with the polishing machine connecting cover 2.

[0021] The bottom of the grinding machine connecting cover 2 forms a rigid first connecting platform 3. A grinding machine connecting structure 8 is provided on the outside of the first connecting platform 3. The grinding machine connecting cover 2 is detachably connected to the grinding machine body through the grinding machine connecting structure 8. The central column 7 extends integrally along the central axis of the inner side of the first connecting platform 3, and the central column 7 is coaxial with the grinding machine connecting structure 8.

[0022] The flexible grinding head 1 has a sealed airbag structure, and a pressure sensor is installed in the sealed cavity inside the flexible grinding head 1. The pressure sensor can detect the pressure in the sealed cavity in real time. The outer wall surface away from the grinding machine connecting cover 2 is the flexible grinding surface 4, and the grinding medium is detachably attached to the outer surface of the flexible grinding surface 4. The side of the flexible grinding head 1 closest to the grinding machine connecting cover 2 is the second connecting platform 5. The flexible grinding head 1 and the second connecting platform 5 are completely bonded together with adhesive. The central column 7 is far from... The end of the first connecting platform 3 is hinged to the center of the second connecting platform 5 via a ball joint. Several adjusting connectors 6 are disposed between the central column 7 and the side wall of the grinding machine connecting cover 2, and are located on the side close to the edge of the second connecting platform 5. That is, the distance between the hinge point of each adjusting connector 6 and the edge of the second connecting platform 5 is much smaller than the distance to the center of the second connecting platform 5. And the two ends of each adjusting connector 6 are respectively hinged to the side of the first connecting platform 3 and the second connecting platform 5 that are close to each other.

[0023] More specifically, the flexible polishing head 1 is inflated at a calibrated air pressure, i.e., the air pressure at which the flexible polishing surface 4 is completely flattened and inflated when the sealed cavity of the flexible polishing head 1 is gradually inflated. In this state, the side of the flexible polishing head 1 that is in contact with the second connecting platform 5 is a horizontal plane, and the flexible polishing surface 4 is also a horizontal plane. Since the second platform 5 and the flexible polishing head 1 are completely bonded together with adhesive, the flexible polishing surface 4 will preferentially deform when the pressure inside the sealed cavity of the flexible polishing head 1 changes. The sealed cavity of the flexible polishing head 1 includes an independent central cavity 14 and a side annular cavity 1. 5. When the surface to be polished is not horizontal, the pressure changes in the central cavity 14 and the side annular cavity 15 are different. For example, if the surface to be polished is a convex surface with a large curvature, when the flexible polishing surface 4 comes into contact with the surface to be polished, the middle area is first compressed. The central cavity 14 can be appropriately depressurized to avoid excessive local pressure. At the same time, the side annular cavity 15 is inflated, and the expansion force is used to make the edge of the flexible polishing surface 4 closely adhere to the convex edge of the polishing area of ​​the surface to be polished. If the surface to be polished is a convex surface with a small curvature, both the central cavity 14 and the side annular cavity 15 are depressurized, but the pressure change in the central cavity 14 is greater than the pressure change in the side annular cavity 15.

[0024] Furthermore, it should be emphasized that the shapes of the central cavity 14 and the side annular cavity 15 are adapted to the shape of the opening of the grinding machine connecting cover 2. More specifically, assuming that the opening of the grinding machine connecting cover 2 is circular, the horizontal cross-sectional shape of the central cavity 14 is a circle with a small radius arranged coaxially with the opening of the grinding machine connecting cover 2, and the side annular cavity 15 is an annulus arranged coaxially with the opening of the grinding machine connecting cover 2. Moreover, the central cavity 14 and the side annular cavity 15 are simply different chambers in the sealed bladder of the flexible grinding head 1, and together they constitute an airbag structure, rather than two separate airbags.

[0025] It also includes a pressure control module, which comprises an air source structure 9, a venting structure 10, and a controller. Both the air source structure 9 and the venting structure 10 are sealed and pass through the second connecting platform 5, communicating with a closed cavity inside the flexible grinding head 1. The controller is signal-connected to both the air source structure 9 and the venting structure 10, and can control the air source structure 9 and the venting structure 10 to inflate or deflate the closed cavity, thereby maintaining a constant actual contact pressure between the flexible grinding head 1 and the surface being ground. The air source structure 9 is a miniature air pump, etc. The venting structure 10 is an electrically controlled venting valve or similar device; more specifically, the pressure control module includes at least two independent air source structures 9, two independent venting structures 10, and a controller, and each air source structure 9 and each venting structure 10 is signal-connected to the controller; the central cavity 14 and the side ring cavity 15 are each respectively provided with an air source structure 9 and a venting structure 10, and the controller can control the air source structure 9 and the venting structure 10 corresponding to the central cavity 14 and the side ring cavity 15 to inflate or deflate the central cavity 14 or the side ring cavity 15 respectively.

[0026] It also includes a detection module 11, which is located on the outer side of the side wall of the grinding machine connecting cover 2 and can rotate synchronously with the grinding machine connecting cover 2. The detection module 11 can detect the radius of curvature and grinding depth of the surface being ground in real time. The detection module 11 is electrically connected to the controller, which can control the air source structure 9 and the air release structure 10 to inflate or deflate the sealed cavity according to the detection results of the detection module 11. More specifically, the detection module 11 includes a ternary laser sensor with three laser emission sources. The curvature of the surface being ground can be detected by projecting the three lasers onto the surface being ground. This technology is relatively mature and will not be described in detail again. Furthermore, as the grinding machine connecting cover 2 rotates, the detection module 11 can be aligned sequentially with the ground area and the unground area. Based on the difference between its distance from the surface of the ground area and the distance from the surface of the unground area, the grinding depth of the ground area can be obtained, thereby ensuring that the grinding depth of each area of ​​the ground surface tends to be consistent after grinding.

[0027] The second connecting platform 5 is a deformable metal plate externally attached to the flexible grinding head 1. The second connecting platform 5 is completely fitted to the flexible grinding head 1, and in the initial state, the outline shape of the second connecting platform 5 is adapted to the outline shape of the cover opening of the grinding machine connecting cover 2, and the area of ​​the second connecting platform 5 is slightly larger than the area of ​​the cover opening of the grinding machine connecting cover 2. Each of the adjusting connecting parts 6 includes an electrically controlled telescopic structure 12 and an external spring 13. The end of the telescopic end of the electrically controlled telescopic structure 12 is ball-jointed with the first platform 3, and the end of the fixed end is ball-jointed with the second platform 5. The electrically controlled telescopic structure 12 is connected to the controller signal. One end of the external spring 13 is connected to the end of the telescopic end of the electrically controlled telescopic structure 12. The connection is configured such that one end is connected to the outer wall of the fixed end of the electrically controlled telescopic structure 12. In the initial state, the electrically controlled telescopic structure 12 is in an extended state under the action of the external spring 13, thereby creating a gap between the second connecting platform 5 and the cover opening of the grinding machine connecting cover 2. When the controller controls the air source structure 9 and the air release structure 10 to inflate or deflate the sealed cavity, the controller synchronously controls each electrically controlled telescopic structure 12 to extend and retract, thereby causing the second platform 5 to deform synchronously with the flexible grinding head 1. The cooperation between each electrically controlled telescopic structure 12 and the second platform 5 enables the flexible grinding surface 4 of the flexible grinding head 1 to completely fit with the surface being ground. The external spring 13 absorbs the instantaneous impact during the grinding process.

[0028] More specifically, in the initial state, the total length of each of the electrically controlled telescopic structures 12 is equal to the length of the central column 7. Since the length of the central column 7 cannot be changed, when the flexible grinding surface 4 comes into contact with the surface to be ground, the electrically controlled telescopic structures 12 extend or retract synchronously and at equal intervals under the control of the controller. The central area of ​​the second connecting platform 5 maintains its original position under the action of the central column 7, while the edge area bends relative to the central area under the action of the electrically controlled telescopic structures 12, thereby making the flexible grinding surface 4 completely fit with the surface to be ground. In this state, the flexible grinding head 1 is clamped between the surface to be ground and the second connecting platform 5, and the downward pressure applied by the grinding machine will pass through the central column 7. The column 7 is transferred to the second connecting platform 5. Since the second connecting platform 5 deforms with the deformation of the flexible grinding head 1, that is, the second connecting platform 5 undergoes an approximate deformation that adapts to the deformation curvature of the flexible grinding head 1 under the combined action of each electrically controlled telescopic structure 12. Since the curvature of the flexible grinding head 1 and the surface to be ground are the same, even if the flexible grinding head 1 has deformed, the second connecting platform 5 can still provide contour support for the flexible grinding head 1 under the action of the aforementioned downward pressure, thereby uniformly squeezing each area of ​​the flexible grinding head 1. Thus, under the action of the aforementioned downward pressure, the second connecting platform 5 pushes the flexible grinding head 1 against the surface to be ground, thereby allowing each area of ​​the flexible grinding surface 4 to grind the surface to be ground under a balanced downward pressure.

[0029] A grinding method using a flexible grinding device that adapts to curved surfaces includes the following steps:

[0030] Step 1: Apply the polishing media to the flexible polishing surface 4 of the flexible polishing head 1, and assemble and connect the flexible polishing device to the main body of the polishing machine through the polishing machine connection structure 8.

[0031] Step 2: Start the detection module 11, which detects the radius of curvature R of the surface being polished and transmits the detection data to the controller;

[0032] Step 3: Based on Step 2, the controller controls each air source structure 9 and each air release structure 10 to fill or release air into the central cavity 14 or side ring cavity 15 of the sealed bladder according to the detection results of the detection module 11, thereby adjusting the internal pressure of each area of ​​the flexible grinding head 1.

[0033] Step 4: While performing Step 3, the controller synchronously controls the electronically controlled telescopic structure 12 in each adjusting connector 6 to extend and retract, so that the second connecting platform 5 deforms accordingly with the deformation of the flexible grinding head 1.

[0034] Step 5: Start the main body of the grinder. The downward pressure applied by the grinder is transmitted to the flexible grinding head 1 through the central column 7. The flexible grinding surface 4 of the flexible grinding head 1 is completely in contact with the surface to be ground under the combined action of the second connecting platform 5, each adjusting connector 6 and the central column 7. The flexible grinding surface 4 completely covers the positive grinding area of ​​the surface to be ground. Under the action of each adjusting connector 6, the flexible grinding head 1 rotates synchronously with the grinder connecting cover 2, thereby grinding the surface to be ground.

[0035] Step Six: During the polishing process, the downward pressure applied by the polishing machine remains constant. The detection module 11 detects and feeds back the changes in the radius of curvature R and polishing depth h of the polished surface to the controller in real time. The controller performs the adjustment operations described in Steps Three and Four in real time based on the detection results of the detection module 11, thereby adjusting the airbag pressure and adjusting the extension and retraction of the connecting parts in a timely manner to ensure that the flexible polishing surface 4 of the flexible polishing head 1 is always in contact with the polished surface during the polishing process and that the contact pressure during polishing is constant.

[0036] In step three, the pressure adjustment methods for the central cavity 14 and the side annular cavity 15 of the sealed cavity inside the flexible grinding head 1 both satisfy the following adjustment formula:

[0037]

[0038] in,

[0039] To achieve the target grinding depth; since the grinding depth needs to be as consistent as possible when grinding the same workpiece, the grinding depth h per unit time is a constant value.

[0040] k is a process coefficient, determined by the particle size of the grinding media and the material of the workpiece being ground. It can be determined experimentally, therefore k is a constant value.

[0041] The contact pressure between the flexible polishing surface and the surface being polished;

[0042] The downward pressure applied to the grinder is expressed in N; since the downward pressure applied by the grinder during the grinding process remains constant in this scheme, F is a constant value.

[0043] The real-time internal pressure of the sealed cavity inside the flexible grinding head;

[0044] The contact area between the flexible polishing surface and the surface being polished;

[0045] In this design, under the calibrated air pressure, the flexible grinding surface 3 of the flexible grinding head 1 is horizontal. During the grinding process, the flexible grinding surface 4 adaptively conforms to the surface being ground under the combined action of the second connecting platform 5, each adjusting connector 6, and the central column 7, thus forming an effective and stable grinding contact area. The area of ​​this grinding contact area is similar to the area of ​​the flexible grinding surface 4. Therefore, here... This can be considered as the area of ​​the flexible polishing surface 4.

[0046] Based on the above, assuming a scenario of grinding a flat surface, and a grinding depth of h per unit time, the internal pressure of the sealed cavity inside the flexible grinding head is: Then we can get:

[0047]

[0048] in,

[0049] The reference pressure is the internal pressure required for the sealed cavity inside the flexible grinding head to grind to a depth of h on a plane per unit time.

[0050] The pressure change caused by increasing or decreasing the pressure inside the sealed cavity of the flexible grinding head:

[0051] As can be seen from the above formula, The main reason for determining the contact pressure between the flexible polishing surface and the surface being polished is... The size of is related to the radius of curvature R of the surface being polished, therefore:

[0052]

[0053] in,

[0054] The airbag tension is determined experimentally or calculated from material properties.

[0055] For the airbag bending stiffness:

[0056] The elastic modulus of the airbag material;

[0057] Poisson's ratio is the ratio of the airbag material.

[0058] The thickness of the airbag;

[0059] The radius of curvature R of the surface being polished is directly detected by the detection module;

[0060] The reference pressure is the internal pressure required for the sealed cavity inside the flexible grinding head to grind to a depth of h on a plane per unit time.

[0061] The geometric characteristic length of the flexible polishing surface is taken as follows: for circular polishing surfaces, the radius is taken; for square or rectangular polishing surfaces, half the length of the short side is taken; and for irregularly shaped polishing surfaces, the minimum radius of rotation is taken. The length is obtained by direct measurement using calipers or a profilometer.

[0062] The contact area between the flexible polishing surface and the surface being polished;

[0063] The pressure change caused by increasing or decreasing the pressure inside the sealed cavity of the flexible grinding head:

[0064] The downward pressure applied to the grinder;

[0065] K1 is the tension-stiffness coupling compensation coefficient of the airbag; it reflects the degree of influence of the airbag's tension and bending stiffness on the pressure; when the airbag tension T is larger and the bending stiffness D is smaller, the airbag is more likely to deform due to tension. At this time, K1 reflects the actual influence on the pressure when tension dominates the deformation; under the condition that the airbag material and thickness are the same, K1 is determined by experiment.

[0066] For curvature adaptation compensation coefficient; when the geometric feature length of the flexible grinding surface The larger the value, the weaker the constraint of the same curvature R on the deformation of the air bladder. It can reflect the sensitivity of flexible polishing surfaces of different sizes to the curvature of the surface being polished; Calibrated by experiments;

[0067] K3 is the pressure-curvature coupling compensation coefficient. When the pressure F is constant, the smaller the curvature R of the polished surface, that is, the smoother the polished surface, the more significant the effect of the pressure on the airbag's contact pressure. K3 can reflect the actual effect of the pressure on the contact pressure of polished surfaces with different curvatures under the same pressure. K3 is calibrated by experiments.

[0068] in, The positive and negative signs represent whether pressure needs to be increased or decreased, respectively. Furthermore, since the pressure changes in the central cavity 14 and the side annular cavity 15 differ when the surface being polished is curved, the aforementioned reference pressure adjustment value is obtained. Next, it is necessary to further calculate the pressure regulation values ​​of the central cavity 14 and the side annular cavity 15; let the pressure regulation coefficient of the central cavity 14 be x1 and the pressure regulation coefficient of the side annular cavity 15 be x2, then:

[0069]

[0070] in,

[0071] This represents the pressure change value that needs to be adjusted in the central cavity;

[0072] The pressure regulation coefficient of the central cavity;

[0073] This represents the pressure change value that needs to be adjusted in the side annular cavity;

[0074] The pressure regulation coefficient of the side annular cavity;

[0075] It should be emphasized that x1 and x2 were obtained through experimental calibration. During the experiment, with other parameters being the same, surfaces with different curvatures were polished to obtain a mapping table of curvature radius R and x1 and x2. During the polishing process, the controller only needs to call the corresponding x1 and x2 according to the curvature R of the polished surface measured by the detection module 11. and The positive and negative signs represent whether pressure needs to be increased or decreased, respectively.

[0076] In step four, the telescopic adjustment method of the electrically controlled telescopic structure 12 in each of the adjusting connectors 6 satisfies the following adjustment formula:

[0077] Let the total length of the electrically controlled telescopic structure 12 during the grinding of the surface be... Then we can get:

[0078]

[0079] in,

[0080] This refers to the total length of the electrically controlled telescopic structure during surface grinding.

[0081] The real-time total length of the electrically controlled telescopic structure;

[0082] The length by which the electrically controlled telescopic structure needs to extend or retract.

[0083] Because the extension or retraction of the telescopic end of the electrically controlled telescopic structure 12 causes deformation of the second connecting platform 5, the external spring 13 will exert a corresponding force on the extension or retraction of the telescopic end of the electrically controlled telescopic structure 12. Furthermore, the pressure adjustment of the sealed cavity inside the flexible grinding head 1 in step three will cause a change in the force exerted by the sealed cavity inside the flexible grinding head 1 on the second connecting platform 5. The second connecting platform 5 needs to deform along with the deformation of the flexible grinding head 1. Moreover, the flexible grinding surface 4, under the combined action of the second connecting platform 5, each adjusting connector 6, and the central column 7, completely adheres to the surface being ground. Therefore:

[0084]

[0085] in,

[0086] The pressure change in the sealed cavity inside the flexible grinding head after increasing or decreasing air in step three:

[0087] The effective working area of ​​the second platform in contact with the flexible grinding head is A. In this scheme, the second platform is completely in contact with the flexible grinding head, that is, A is the area of ​​the second platform.

[0088] The downward pressure applied to the grinder;

[0089] The contact area between the flexible polishing surface and the surface being polished;

[0090] The airbag tension is determined experimentally or calculated from material properties.

[0091] The radius of curvature R of the surface being polished is directly detected by the detection module;

[0092] The geometric characteristic length of the flexible polishing surface is obtained by directly measuring the geometric dimensions of the polishing surface;

[0093] For the airbag bending stiffness:

[0094] The spring constant of the external spring;

[0095] This is a supplementary coefficient representing the influence of the airbag on the electrically controlled telescopic structure under pressure. It reflects the degree of influence of the coupling effect of the airbag bending stiffness, airbag tension, and the curvature of the polished surface on the telescopic amount of the electrically controlled telescopic structure. When the airbag bending stiffness D, the airbag tension T, or the polished surface curvature R is larger, the airbag is more constrained and less likely to deform. It can reflect the actual impact of the above-mentioned constraints on the expansion and contraction of the electric telescopic structure, assuming that parameters such as airbag material, thickness, grinding media, and workpiece material are the same. Calibrated by experiments;

[0096] B: The stiffness coefficient of the second platform.

[0097] Finally, it should be noted that the flexible sanding device and sanding method with adaptive curved surfaces described in this solution are more suitable for the production of parts with similar dimensions of different models. For example, in reality, this solution has been used for the surface sanding of violin and guitar panels. The dimensions and curvatures of different models of panels in these structures are relatively similar, so the calibration parameters in the calculation only need to be calibrated once. Of course, this does not mean that this solution can only be used for surface sanding of violin and guitar panels, but that in the sanding of other parts with significantly different dimensions of different models, an experimental calibration process is required for each model.

[0098] The above are the preferred embodiments described in this invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention.

Claims

1. A flexible grinding device that adapts to curved surfaces, characterized in that: The system includes a flexible grinding head (1), a grinding machine connecting cover (2), and adjusting connectors (6). The flexible grinding head (1) is spaced apart from the opening of the grinding machine connecting cover (2). A central column (7) is provided inside the grinding machine connecting cover (2) along the central axis, and one end of the central column (7) extends to the opening of the grinding machine connecting cover (2) and is hinged to the center of the flexible grinding head (1). Several adjusting connectors (6) are connected between the flexible grinding head (1) and the grinding machine connecting cover (2). Between the mill connecting cover (2), when the side of the flexible grinding head (1) away from the mill connecting cover (2) comes into contact with the surface to be ground, the downward pressure applied to the mill connecting cover (2) is transmitted to the flexible grinding head (1) through the central column (7), so that the flexible grinding head (1) adapts to fit the surface to be ground. Several of the adjusting connecting parts (6) cooperate with each other to transmit stable torque during the grinding process, driving the flexible grinding head (1) to rotate synchronously with the mill connecting cover (2).

2. The flexible grinding device with surface self-adaptation according to claim 1, characterized in that: The bottom of the grinding machine connecting cover (2) forms a rigid first connecting platform (3). The outer side of the first connecting platform (3) is provided with a grinding machine connecting structure (8). The grinding machine connecting cover (2) is detachably connected to the grinding machine body through the grinding machine connecting structure (8). The central column (7) extends integrally along the central axis of the inner side of the first connecting platform (3), and the central column (7) and the grinding machine connecting structure (8) are coaxial.

3. The flexible grinding device with surface self-adaptation according to claim 2, characterized in that: The flexible grinding head (1) is a sealed airbag structure. Its outer wall surface away from the grinding machine connecting cover (2) is a flexible grinding surface (4). Grinding media is detachably attached to the outer surface of the flexible grinding surface (4). The side of the flexible grinding head (1) near the grinding machine connecting cover (2) is a second connecting platform (5). The end of the central column (7) away from the first connecting platform (3) is hinged to the center of the second connecting platform (5) through a ball joint. Several adjusting connectors (6) are arranged between the central column (7) and the side wall of the grinding machine connecting cover (2). The two ends of each adjusting connector (6) are respectively hinged to the side of the first connecting platform (3) and the second connecting platform (5) that are close to each other.

4. The flexible grinding device with surface self-adaptation according to claim 1, characterized in that: It also includes a pressure control module, which includes an air source structure (9), a venting structure (10), and a controller. The air source structure (9) and the venting structure (10) are both sealed and pass through the second connecting platform (5) to communicate with the sealed cavity inside the flexible grinding head 1. The controller is connected to the air source structure (9) and the venting structure (10) respectively, and can control the air source structure (9) and the venting structure (10) to inflate or deflate the sealed cavity, so that the actual contact pressure between the flexible grinding head (1) and the surface being ground remains constant.

5. The flexible grinding device with surface self-adaptation according to claim 1, characterized in that: It also includes a detection module (11), which is located on the outside of the side wall of the grinding machine connecting cover (2). The detection module (11) can detect the radius of curvature R and grinding depth h of the surface being ground in real time. The detection module (11) is electrically connected to the controller. The controller can control the air source structure (9) and the air release structure (10) to inflate or release the air from the sealed cavity according to the detection results of the detection module (11).

6. The flexible grinding device for adaptive curved surfaces according to claim 5, characterized in that: The second connecting platform (5) is a deformable metal plate externally connected to the flexible grinding head (1); each of the adjusting connecting parts (6) includes an electrically controlled telescopic structure (12) and an external spring (13). The telescopic end of the electrically controlled telescopic structure (12) is ball-jointed with the first platform (3), and the fixed end is ball-jointed with the second platform (5). The electrically controlled telescopic structure (12) is connected to the controller signal. One end of the external spring (13) is connected to the telescopic end of the electrically controlled telescopic structure (12), and the other end is connected to the electrically controlled telescopic structure. The outer wall of the fixed end of the structure (12) is connected; when the controller controls the air source structure (9) and the air release structure (10) to inflate or release the air from the sealed bladder, the controller synchronously controls each electrically controlled telescopic structure (12) to extend and retract, so that the second platform (5) deforms synchronously with the flexible grinding head (1). Each electrically controlled telescopic structure (12) and the second platform (5) cooperate with each other to make the flexible grinding surface (4) of the flexible grinding head (1) completely fit with the grinding surface. The external spring (13) absorbs the instantaneous impact during the grinding process.

7. A grinding method for a flexible grinding device with surface self-adaptation according to any one of claims 1 to 6, characterized in that: Includes the following steps: Step 1: Place the grinding media on the flexible grinding surface (4) of the flexible grinding head (1), and assemble and connect the flexible grinding device to the main body of the grinding machine through the grinding machine connection structure (8); Step 2: Start the detection module (11), which detects the radius of curvature R of the surface being polished and transmits the detection data to the controller; Step 3: Based on step 2, the controller controls the air source structure (9) and the air release structure (10) to fill the sealed cavity with air or release the sealed cavity according to the detection result of the detection module (11), thereby adjusting the pressure of the sealed cavity inside the flexible grinding head (1). Step 4: While performing Step 3, the controller synchronously controls the electric telescopic structure (12) in each adjusting connector (6) to extend and retract, so that the second connecting platform (5) deforms accordingly with the deformation of the flexible grinding head (1); Step 5: Start the main body of the grinder. The downward pressure applied by the grinder is transmitted to the flexible grinding head (1) through the central column (7). The flexible grinding surface (4) of the flexible grinding head (1) is completely in contact with the surface to be ground under the combined action of the second connecting platform (5), each adjusting connector (6) and the central column (7). The flexible grinding head (1) rotates synchronously with the grinder connecting cover (2) under the action of each adjusting connector (6), thereby grinding the surface to be ground. Step 6: During the polishing process, the downward pressure applied by the polishing machine remains unchanged. The detection module (11) detects and feeds back the change data of the radius of curvature R and polishing depth h of the polished surface in real time to the controller. The controller performs the adjustment operations described in Step 3 and Step 4 in real time according to the detection results of the detection module (11), thereby adjusting the airbag pressure and adjusting the extension and retraction of the connecting parts in a timely manner, so as to ensure that the flexible polishing surface (4) of the flexible polishing head (1) is always completely in contact with the polished surface during the polishing process and the contact pressure during polishing is constant.

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