Bionic wall-climbing sliding suction cup

Abstract

This invention discloses a biomimetic wall-climbing sliding suction cup, relating to the field of biomimetic wall-climbing technology. It includes a biomimetic suction cup module comprising a negative pressure cavity. The opening side of the negative pressure cavity is provided with a flexible suction cup lip, which can adhere to a wall surface and change the contact pressure and friction with the wall. A driving module is installed inside the negative pressure cavity to drive the biomimetic suction cup module to move on the wall surface. A load is installed at the end of the biomimetic suction cup module away from the flexible suction cup lip. The flexible suction cup lip is flexible and can adapt to the surface shape through passive deformation, while the negative pressure cavity is rigid and serves as the main load-bearing component of this invention. The biomimetic wall-climbing sliding suction cup provided by this invention is suitable for adsorption and climbing spraying operations on complex surfaces, and has advantages such as good surface adaptability, no guide rail limitations, simple structure, low manufacturing cost, and wide applicability.

Description

Technical Field

[0001] This invention relates to the field of biomimetic wall-climbing technology, and in particular to a biomimetic wall-climbing sliding suction cup. Background Technology

[0002] Wall-climbing mobile devices can move rapidly across various surfaces such as floors, walls, and ceilings. Equipped with appropriate end effectors, they can replace human labor in certain aerial wall-mounted scenarios, thereby improving work efficiency and reducing the risks associated with working in special environments. Wall-climbing robots are widely used in aerospace, shipbuilding, and construction industries, for example, in aircraft skin inspection, wall-climbing drilling, ship cleaning and painting, high-rise building painting, and oil tank grinding and painting. Wall-climbing robots mainly consist of an attachment mechanism and a movement mechanism. Currently, the adhesion methods used by wall-climbing robots mainly include negative pressure adhesion, magnetic adhesion, pneumatic adhesion, mechanical adhesion, electroadhesion, and biomimetic adhesion methods.

[0003] Currently, wall-climbing robots are mainly designed for large open spaces on external surfaces. However, due to their large size, they are not suitable for narrow or elongated spaces. Some wall-climbing robots require guide rails for movement and climbing, which are complex to design and build and can interfere with certain tasks, such as full-surface spraying. Therefore, developing a wall-climbing device that is suitable for complex surfaces in large or narrow spaces, has no track limitations, is simple in structure, low in cost, and is safe and stable is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a biomimetic wall-climbing sliding suction cup to solve the problems existing in the prior art. It is suitable for complex surface adsorption and crawling spraying operations and has the advantages of good surface adaptability, no guide rail limitation, simple structure, low manufacturing cost, and wide applicability.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a biomimetic wall-climbing sliding suction cup, comprising a biomimetic suction cup module, the module including a negative pressure cavity, the opening side of which has a flexible suction cup lip, which can adhere to a wall surface and change the contact pressure and friction with the wall surface; a drive module, installed inside the negative pressure cavity, for driving the biomimetic suction cup module to move on the wall surface; and a load, fixedly installed at the end of the biomimetic suction cup module away from the flexible suction cup lip; the flexible suction cup lip is flexible and can passively deform to adapt to the surface, and the negative pressure cavity is... The rigidity serves as the main support of this invention. During operation, the flexible lip of the suction cup adheres to the wall surface, and the drive module rolls in contact with the wall. When the invention is stationary, the suction force is increased to make the pressure between the flexible lip of the suction cup and the negative pressure chamber lower than the external pressure, thus adhering to the wall surface. When movement is required, the suction force is reduced. At this time, the contact force between the flexible lip of the suction cup and the wall surface is reduced, becoming less than the driving force of the drive module. As a result, the drive module moves the device along the wall surface. During the movement, the flexible lip of the suction cup remains adhered to the wall surface, providing suction force and preventing the device from detaching and falling off the wall.

[0007] Optionally, the negative pressure cavity is connected to a high-pressure pneumatic tube, which is used to connect to an external vacuum device. The flexible lip of the suction cup is bonded to both the negative pressure cavity and the high-pressure pneumatic tube.

[0008] Optionally, the flexible lip of the suction cup is provided with multiple biomimetic pressure relief holes, and a biomimetic pressure relief valve is provided on the outside of the biomimetic pressure relief holes. The biomimetic pressure relief valve is used to control the gas flow of the biomimetic pressure relief holes, thereby ensuring that the positive pressure at the contact interface between the flexible lip of the suction cup and the wall is reduced under the premise of setting negative pressure in the negative pressure cavity. Multiple biomimetic convex structures are distributed on the inner side of the flexible lip of the suction cup, which can reduce the actual contact area between the flexible lip of the suction cup and the wall, thereby reducing the equivalent coefficient of friction. The overall design of the suction cup's flexible lip structure is inspired by the suction cavity of the catfish. It includes circumferentially distributed biomimetic pressure relief holes and an array of biomimetic convex hull structures. The biomimetic pressure relief holes simulate the groove structure on both sides of the catfish's oral cavity, reducing the positive pressure at the interface between the lip and the wall while ensuring a certain negative pressure inside the cavity. The biomimetic convex hull structure simulates the convex hull microstructure of the catfish's lip, reducing the equivalent friction coefficient by decreasing the actual contact area with the wall and also having a certain pressure equalization effect. The two structures complement each other to reduce lip friction and meet the requirements for suction and crawling.

[0009] Optionally, the biomimetic convex hull structure friction reduction design reduces friction by decreasing the actual contact area of ​​the interface, and the equivalent coefficient of friction decreases with increasing unit load (within the elastic deformation limit). If the radius of the biomimetic convex hull structure is R, and the total load is W... 总The number of biomimetic convex hull structures is n, the equivalent elastic modulus of the contact interface is E', the hardness of the biomimetic convex hull structure material is H, and elastic contact occurs at the contact interface. Based on molecular-mechanical theory, the equivalent coefficient of friction f is:

[0010]

[0011] In the formula, α and β are determined by the physical and mechanical properties of the friction surfaces, and β represents the actual friction coefficient, which is a constant derived from elastic contact theory. The equivalent friction coefficient satisfies:

[0012]

[0013] Optionally, the biomimetic pressure relief orifice has an elliptical cross-section. A groove is provided on the outer ring of the orifice, located on the side of the suction cup's flexible lip away from the wall. The groove and the channel of the biomimetic pressure relief orifice form a valve. The opening and closing size of the valve is controlled by its own elasticity and the negative pressure generated by the airflow, thereby achieving passive control of gas leakage. Specifically, the thin wall between the groove and the channel of the biomimetic pressure relief orifice forms the valve, and the outer end of the orifice uses a thin-wall design for passive control of gas leakage. When the gas flow rate is low, the pressure difference across the thin wall of the orifice is small, and the outer cross-sectional area of ​​the orifice remains essentially unchanged. When the gas flow rate is too high, a pressure difference is generated across the thin wall of the orifice, causing the outer walls to approach each other, reducing the cross-sectional area of ​​the orifice and thus inhibiting gas inflow. The cross-sectional area of ​​the biomimetic pressure relief orifice has a significant, linearly related effect on the gas leakage rate and the average pressure at the contact interface. A larger cross-sectional area results in a greater gas leakage rate and a better pressure relief effect. The height gap at the contact interface has a significant impact on the gas leakage rate but a relatively smaller impact on the average pressure at the interface. A larger height gap leads to a linear increase in gas leakage, but the average pressure at the interface decreases with increasing gas velocity, resulting in a slight decrease in the pressure relief effect. The cross-sectional area of ​​the biomimetic pressure relief orifice is between 0.5 and 2 mm. 2 The interface height design gap is between 0.05-0.5mm.

[0014] Optionally, the drive module includes a motor, which is fixed to the bottom of the negative pressure chamber via a motor mount. One end of the motor is provided with a guide wheel, which is movably mounted to the bottom of the negative pressure chamber via a guide wheel support. The other end of the motor is provided with a drive shaft, which is mounted on a drive wheel support via bearings. The drive wheel support is fixed to the bottom of the negative pressure chamber, and drive wheels are mounted at both ends of the drive shaft. A bevel gear mounted on the output shaft of the motor meshes with a bevel gear fixedly mounted on the drive shaft for transmission. The motor mount, drive wheel support, and guide wheel support are 3D printed from nylon material to meet the requirements of rigidity and lightweight.

[0015] Optionally, the drive wheel includes a hub, which is connected to one end of the drive shaft via a flange coupling, and the hub is covered with a friction-enhancing rubber sheath.

[0016] Optionally, the flexible lip of the suction cup is made using a combination of upper, middle, and lower molds, 3D technology, and casting process. A three-part mold (upper, middle, and lower) is designed based on the structure of the flexible lip of the suction cup to facilitate subsequent demolding. High-precision photopolymerization 3D printing technology is used for mold manufacturing. After the mold is assembled and fixed, a mixed and vacuum-treated silicone solution is poured in, and the mixture is allowed to stand at room temperature until the silicone rubber is completely cured before demolding to obtain the flexible lip sample of the suction cup. The biomimetic convex structure includes flexible silicone rubber, a fixed mesh, and rigid beads. The hardness of the flexible silicone rubber is 40–60 HA, and the size of the rigid beads is 0.5–2 mm, which can be glass beads. The rigid beads are embedded in the mesh holes of the fixed mesh and the recesses of the lower mold. The casting process is used to bond the fixed mesh to the surface of the flexible silicone rubber, completing the bonding between the rigid beads and the flexible silicone rubber, thus obtaining the biomimetic convex structure. The biomimetic pressure relief hole is obtained by direct casting through a double-layered concentric cylinder in the upper mold.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] This invention addresses the need for automated spraying on complex surfaces in confined spaces. Inspired by the catfish (Siniperca chuatsi), which is capable of adsorption and crawling, it presents a biomimetic wall-climbing sliding suction cup. An external vacuum generator provides negative pressure to overcome gravity, while a biomimetic flexible lip design reduces pressure and friction, allowing for both adsorption and sliding. Prototype positioning and surface movement are achieved through a three-wheeled system. This invention features a simple structure, wide applicability, safety, and stability, and can meet the needs of adsorption and crawling spraying on various wall materials in confined spaces. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the biomimetic wall-climbing sliding suction cup of the present invention;

[0021] Figure 2 This is a schematic diagram of the invention climbing a vertical wall.

[0022] Figure 3 This is a schematic diagram of the invention climbing the wall on the top surface;

[0023] Figure 4 This is a schematic diagram of the curved wall climbing mechanism inside the cylinder according to the present invention;

[0024] Figure 5 This is a schematic diagram of the biomimetic convex hull structure of the present invention;

[0025] Figure 6 for Figure 5 AA cross-section view;

[0026] Figure 7 This is a schematic diagram of the biomimetic pressure relief hole in the open state of the present invention;

[0027] Figure 8 for Figure 7 BB cross-sectional diagram;

[0028] Figure 9 This is a schematic diagram of the closed state of the biomimetic pressure relief hole of the present invention;

[0029] Figure 10 For the present invention Figure 9 A schematic diagram of the CC cross-section;

[0030] Figure 11 This is a schematic diagram of the mold composition for manufacturing the flexible lip of the suction cup according to the present invention;

[0031] Figure 12 This is a partial structural diagram of the drive module of the present invention;

[0032] Explanation of reference numerals in the attached drawings: 1-High-pressure pneumatic pipe, 2-Bionic pressure relief valve, 3-Bionic pressure relief hole, 4-Bionic convex structure, 5-Drive wheel, 6-Motor, 7-Guide wheel, 8-Suction cup flexible lip, 9-Rigid cavity shell, 10-Load; 11-Vertical wall, 12-Top surface, 13-Inner curved surface of cylinder, 14-Fixed mesh, 15-Rigid bead, 16-Flexible silicone rubber, 17-Pressure relief hole channel, 18-Lip contact side with wall, 19-Outer side of lip, 20-Upper mold, 21-Middle mold, 22-Lower mold, 23-Lower mold recess, 24-Double-layer concentric cylinder, 25-Friction-enhancing rubber wheel skin, 26-Hub, 27-Drive wheel support, 28-Bearing, 29-Bevel gear, 30-Drive shaft, 31-Flange coupling, 32-Motor base, 33-Guide wheel support. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The purpose of this invention is to provide a biomimetic wall-climbing sliding suction cup to solve the problems existing in the prior art. It is suitable for complex surface adsorption and crawling spraying operations and has the advantages of good surface adaptability, no guide rail limitation, simple structure, low manufacturing cost, and wide applicability.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] This invention is inspired by the inverted-mouth catfish, which possesses suction-climbing capabilities. The catfish's suction cavity mainly includes its teeth, upper and lower jaws, lower lip, and labial groove. The lower lip surface has a convex structure, characterized by small, dense convex edges and large, sparse convex interiors. The convex height is approximately 200 μm, providing a certain degree of friction reduction during suction-climbing. The labial groove is located in the middle of the left and right sides of the suction cup opening, connecting the oral cavity with the external environment, ensuring that the catfish can breathe while adhering to the suction wall, and also regulating the suction force of the suction cup opening. Based on this, this invention relates to a biomimetic wall-climbing sliding suction cup. (Refer to the attached diagram.) Figure 1 Appendix Figure 5 Appendix Figure 6 Appendix Figure 7 Appendix Figure 8 Appendix Figure 9 Appendix Figure 10 Appendix Figure 11 and attached Figure 12As shown, its structure includes a bionic suction cup module and a driving module. The bionic suction cup module includes a negative pressure cavity, with a flexible suction cup lip 8 on the opening side of the negative pressure cavity. The flexible suction cup lip 8 can adhere to the wall surface and can change the contact pressure and friction with the wall surface. The negative pressure cavity is connected to a high-pressure pneumatic pipe 1, which is used to connect an external vacuum device. The flexible suction cup lip 8, the negative pressure cavity, and the high-pressure pneumatic pipe 1 are all bonded and fixed. The driving module is installed inside the negative pressure cavity to drive the bionic suction cup module to move on the wall surface. A load 10 can be installed on the rigid cavity shell 9 at the end of the bionic suction cup module away from the flexible suction cup lip 8. The flexible suction cup lip 8 is flexible and can adapt to the surface through passive deformation. The negative pressure cavity is rigid and serves as the main load-bearing body of the invention. Figure 2 , Figure 3 and Figure 4 As shown, the present invention can achieve crawling on vertical wall surface 11, top surface 12 and inner curved surface 13 of cylinder.

[0037] The suction cup flexible lip 8 is inspired by the adsorption cavity of the catfish and includes circumferentially distributed biomimetic pressure relief holes 3 and an array of biomimetic convex hull structures 4. The biomimetic pressure relief holes 3 simulate the groove structure on both sides of the catfish's oral cavity, reducing the positive pressure at the interface between the lip and the wall while ensuring a certain negative pressure inside the cavity. The biomimetic convex hull structure 4 simulates the convex hull microstructure of the catfish's lip, reducing the equivalent friction coefficient by decreasing the actual contact area with the wall and having a certain pressure equalization effect. The two structures match each other to reduce the friction of the lip and meet the adsorption and crawling requirements. Specifically, the flexible lip 8 of the suction cup has multiple biomimetic pressure relief holes 3. The biomimetic pressure relief hole 3 is provided with a biomimetic pressure relief valve 2 at one end near the outer side 19 of the lip. The biomimetic pressure relief valve 2 is used to control the gas flow of the biomimetic pressure relief hole 3, so as to reduce the positive pressure at the contact interface between the lip of the flexible lip 8 and the wall surface 18 under the premise of setting negative pressure in the negative pressure cavity. The contact side 18 between the lip of the flexible lip 8 and the wall surface has multiple biomimetic convex structures 4, which can reduce the actual contact area between the flexible lip 8 of the suction cup and the wall surface, thereby reducing the equivalent friction coefficient. The overall design of the suction cup flexible lip 8 is inspired by the suction cavity of the catfish. The biomimetic pressure relief hole 3 simulates the groove structure on both sides of the catfish's oral cavity, reducing the positive pressure at the interface between the lip and the wall while ensuring a certain negative pressure inside the cavity. The biomimetic convex hull structure 4 simulates the convex hull microstructure of the catfish's lip, reducing the equivalent friction coefficient by decreasing the actual contact area with the wall and having a certain pressure equalization effect. The two structures match each other to reduce the friction of the lip and meet the suction and crawling requirements.

[0038] The biomimetic wall-climbing sliding suction cup of this invention experiences different forces on the bottom, vertical, and ceiling surfaces of the wall. Taking the platform's forward movement direction as the tangential direction and the direction perpendicular to the forward movement direction as the normal direction, when the suction cup is on the bottom surface, both gravity and the suction force of the negative pressure cavity are normal positive forces. The frictional force of the suction cup's flexible lip and the frictional force of the drive wheel are the tangential resistance and driving force, respectively. When this invention moves at a constant speed and the drive wheel does not slip, neglecting the frictional resistance of the driven wheel, the equilibrium equation is:

[0039] N1 + N2 = F 吸 +G (1)

[0040] F 驱 =f=u·F 接 (2)

[0041] f 静 =u 轮 ·N1≥F 驱 (3)

[0042] In the formula, N1 is the normal force of the drive wheel; N2 is the normal force of the guide wheel; F 吸 G represents the adsorption force of the negative pressure cavity, and F represents the total weight of the invention. 驱 f is the static friction force exerted by the wall surface on the drive wheel during its rolling motion; f is the frictional resistance generated between the flexible lip 8 of the suction cup and the wall surface during the forward movement of the present invention; u is the equivalent coefficient of friction between the flexible lip 8 of the suction cup and the wall surface; F 接 The positive pressure between the flexible lip 8 of the suction cup and the wall surface; u 轮 The maximum static friction coefficient of the drive wheel. When moving along the vertical wall, the adsorption force of this invention is the normal force, while gravity, lip friction, and drive wheel friction are tangential forces. If the platform continues to move at a constant speed and the drive wheel does not slip, then the equilibrium equation is:

[0043] N1+N ＝ F 吸 (4)

[0044]

[0045] f 静 =u 轮 ·N1≥F 驱 (6)

[0046] f = u·F 接 (7)

[0047] When moving on the bottom surface, the normal force includes gravity and negative pressure adsorption force. However, unlike crawling on the bottom surface, the normal positive pressure of the drive wheel is the adsorption force after overcoming gravity. The tangential force includes the lip friction force and the drive wheel friction force, the same as when crawling on the bottom surface. To ensure uniform motion and no slippage of the drive wheel, the equilibrium equation is:

[0048] N1 + N2 = F 吸 -G (8)

[0049] F 驱 =f=u·F 接 (9)

[0050] f 静 =u 轮 ·N≥F 驱 (10)

[0051] f = u·F 接 (11)

[0052] Specifically, if the maximum static friction coefficient of the drive wheel is less than 1, the negative pressure chamber adsorption force required for vertical upward crawling and top surface crawling is the same under the same motion speed; if the maximum static friction coefficient of the drive wheel is less than 1, the negative pressure chamber adsorption force required for vertical upward crawling under the same conditions is greater; conversely, when the maximum static friction coefficient of the drive wheel is greater than 1, the negative pressure chamber adsorption force required for top surface crawling under the same conditions is the greatest.

[0053] The biomimetic convex hull structure 4 reduces friction by decreasing the actual contact area of ​​the interface, and the equivalent coefficient of friction decreases with increasing unit load (within the elastic deformation limit). If the radius of the biomimetic convex hull structure 4 is R, and the total load is W... 总 The biomimetic convex hull structure has four components, numbered n, with an equivalent elastic modulus of E' at the contact interface. The material hardness of the four biomimetic convex hull structures is H. Elastic contact occurs at the contact interface. Based on molecular-mechanical theory, the equivalent coefficient of friction f is:

[0054]

[0055] In the formula, α and β are determined by the physical and mechanical properties of the friction surfaces, and β represents the actual friction coefficient, which is a constant derived from elastic contact theory. The equivalent friction coefficient satisfies:

[0056]

[0057] Further preferably, the bionic pressure relief hole 3 has an elliptical cross-section; the outer ring of the bionic pressure relief hole 3 has a groove, which is located on the outer side 19 of the flexible lip 8 of the suction cup. The thin wall between the groove and the pressure relief hole channel 17 of the bionic pressure relief hole 3 forms a bionic pressure relief hole valve 2. The opening and closing size of the bionic pressure relief hole valve 2 is controlled by the elasticity of the valve itself and the negative pressure generated by the airflow, thereby achieving passive control of the gas leakage. Specifically, the outer end of the bionic pressure relief hole 3 adopts a thin-wall design to passively control the gas leakage flow. When the gas flow rate is low, the pressure difference on both sides of the thin wall of the bionic pressure relief hole 3 is small, and the cross-sectional area of ​​the outer side of the bionic pressure relief hole 3 remains basically unchanged; when the gas flow rate is too high, the pressure difference on both sides of the thin wall of the outer side of the bionic pressure relief hole 3 causes the walls of the outer wall of the bionic pressure relief hole to move closer to each other, and the cross-sectional area of ​​the bionic pressure relief hole 3 decreases, thereby inhibiting the gas inflow. The area variation of the biomimetic pressure relief orifice 3 has a significant, linearly related effect on the gas leakage rate and the average pressure at the contact interface. A larger cross-sectional area results in a greater gas leakage rate and a better pressure relief effect. The height gap at the contact interface has a significant impact on the gas leakage rate but a relatively smaller impact on the average pressure at the interface. A larger height gap leads to a linear increase in gas leakage, but the average pressure at the interface decreases with increasing gas velocity, resulting in a slight decrease in the pressure relief effect. The cross-sectional area of ​​the biomimetic pressure relief orifice 3 is between 0.5 and 2 mm. 2 The interface height design gap is between 0.05-0.5mm.

[0058] The flexible lip 8 of the suction cup of this invention is manufactured using an upper mold 20, a middle mold 21, and a lower mold 22, combined with 3D technology and a casting process. Rigid beads 15 are embedded in the mesh holes of a fixing mesh 14 and the recess 23 of the lower mold. The casting process then bonds the fixing mesh 14 to the surface of the flexible silicone rubber 16, completing the bonding between the rigid beads 15 and the flexible silicone rubber 16, thus creating a biomimetic convex structure 4. The biomimetic pressure relief hole 3 is obtained by direct casting through the double-layered concentric cylinder 24 of the upper mold 20. The manufacturing process of the flexible lip 8 of the suction cup is detailed below:

[0059] 1) Based on the required prototype model, the mold was designed using Solidworks, and printed using an Anycubic Photon M3 UV-curing printer. After printing, the mold was cleaned to obtain the optimized biomimetic convex hull prototype casting mold. To ensure that the biomimetic convex hull structure can bond well with the silicone rubber and is not easily detached, more than half of the rigid beads were embedded inside the skin during the prototype design.

[0060] 2) Lay a layer of fixing mesh 14 on the bottom plate of the mold, and make the mesh of the fixing mesh 14 correspond to the recess 23 of the lower mold.

[0061] 3) Place the rigid bead 15 at the corresponding lower mold recess 23 position on the mold base plate, apply a certain pressure to make the rigid bead 15 completely adhere to the lower mold recess 23, at which time the corresponding fixing mesh 14 hole will be slightly deformed and will wrap the rigid bead 15. Then combine the mold outer frame with the base plate and seal it with tape.

[0062] 4) Slowly pour in the vacuum-treated silicone solution, fill it up, place it on the biomimetic surface to form a mold and fix it. Let it stand at room temperature for 4 hours. After the rubber has cured, demold it to complete the preparation of the rigid lattice friction-reducing sample.

[0063] Furthermore, the drive module includes a motor 6, which is fixed to the bottom of the negative pressure chamber via a motor mount 32. One end of the motor 6 has a guide wheel 7, which is movably mounted on the bottom of the negative pressure chamber via a guide wheel support 33. The other end of the motor 6 has a drive shaft 30, which is mounted on a drive wheel support 27 via a bearing 28. The drive wheel support 27 is fixed to the bottom of the negative pressure chamber. Drive wheels 5 are mounted at both ends of the drive shaft 30. A bevel gear 29 mounted on the output shaft of the motor 6 meshes with a bevel gear 29 fixedly mounted on the drive shaft 30 for transmission. The motor mount 32, drive wheel support 27, and guide wheel support 33 are 3D printed from nylon material to meet rigidity and lightweight requirements. The drive wheel 5 includes a hub 26, which is connected to one end of the drive shaft 30 via a flange coupling 31. The hub 26 is covered with a friction-enhancing rubber wheel skin 25.

[0064] Based on the design of the test sample for the convex hull friction-reducing interface on the inner side of the flexible lip 8 of the suction cup in this invention, the variation law of the equivalent friction coefficient with the total load, the radius of the biomimetic convex hull structure 4, and the number of the four biomimetic convex hull structures was investigated. The test adopted the controlled variable method, and the friction force was measured by making the contact interface slide at a constant speed of v = 100 mm / s, and then the equivalent friction coefficient was calculated. The results show that, under the premise of avoiding structural damage, the equivalent friction coefficient and W (-1 / 3) D (2 / 3) n (1 / 3) The correlation is linear, which verifies the correctness of the theoretical formula for the equivalent friction coefficient.

[0065] Specifically, the change in the cross-sectional area of ​​the bionic pressure relief hole 3 has a significant impact on the gas leakage and the average pressure at the contact interface, showing a linear correlation. The larger the cross-sectional area of ​​the bionic pressure relief hole 3, the greater the gas leakage and the better the interface pressure relief effect. The flow field distribution shows that outside air flows into the contact interface through the bionic pressure relief hole 3. In the region of the bionic pressure relief hole 3, the flow velocity is high. Guided by the interface gaps formed by the lattice structure, the gas diffuses circumferentially towards the interface and eventually enters the low-pressure region within the cavity. The pressure distribution shows that, influenced by the gas flowing into the bionic pressure relief hole 3, the vacuum level in the low-velocity region of the outer ring of the contact interface is significantly reduced, while the pressure is lower in the region with higher flow velocity, especially near the bionic pressure relief hole 3. As the diameter of the bionic pressure relief hole 3 increases, the overall average vacuum pressure of the contact interface gradually decreases, i.e., the interface contact pressure gradually decreases, and the pressure relief effect becomes more obvious. This is combined with the changes in gas leakage and average contact pressure with increasing outlet negative pressure under bionic pressure relief hole diameters of 0.2 mm to 1 mm. It can be seen that the gas leakage gradually increases with the increase of the diameter of the bionic pressure relief hole 3, and the rate of increase remains basically unchanged; the average negative pressure vacuum decreases with the increase of the diameter of the bionic pressure relief hole, and shows a linear correlation; the pressure relief effect can be significantly controlled by adjusting the size of the diameter of the bionic pressure relief hole 3, but at the same time, it will cause a large change in the gas leakage. The unit pressure relief first increases and then decreases with the increase of the diameter of the bionic pressure relief hole, and the maximum is achieved when the diameter of the bionic pressure relief hole is 0.6 mm.

[0066] Specifically, the biomimetic convex hull structure 4 at the lip boundary surface causes a gap at the sealing contact interface. Changing the lattice structure parameters also affects the sealing and pressure relief performance of the contact interface. The flow field and pressure distribution of the contact models with height gaps of 0.08mm, 0.12mm, and 0.16mm are analyzed. The flow field distribution shows that the circumferential flow distribution of the gas at the interface is generally the same. As the height gap increases, the gas velocity at the contact interface gradually increases, especially in the high-velocity region near the biomimetic pressure relief hole, which is because the viscous resistance at the interface inhibits the fluid flow when the height gap is too small. The pressure distribution cloud map shows that the pressure relief effect at the interface gradually decreases with increasing height gap, and the low-pressure region near the biomimetic pressure relief hole 3 gradually increases, mainly due to the increased flow velocity. The gas leakage is highly sensitive to changes in the interface height gap and increases linearly with increasing height. When the height gap increases from 0.08mm to 0.16mm, the gas leakage increases by approximately 35.7%. The interfacial pressure relief effect gradually decreases with increasing gap height. A gap height of 0.08 mm provides the best pressure relief effect while ensuring minimal gas leakage. Under the three gap height sizes, the average interfacial pressure ranges from -6800 to 7200 Pa, with pressure difference changes of less than 10%, showing little difference in pressure relief effect. From the perspective of gas pressure relief alone, a smaller interfacial gap is better. However, an excessively small gap increases the actual contact area between the flexible lip and the wall surface, increasing intermolecular forces and thus reducing the pressure relief effect.

[0067] Specifically, considering the flow field distribution and pressure relief under wedge-shaped height gaps caused by different sizes of biomimetic convex hull structures, and denoted by the gas flow direction, the height gap increases from 0.08 mm to 0.16 mm (denoted as 0.08-0.16 mm), and vice versa (denoted as 0.16 mm-0.08 mm). Comparing the flow field contour maps and pressure field maps of the two models, it can be seen that the flow velocity of the 0.16-0.08 mm wedge gap group is higher than that of the 0.08-0.16 mm group, while the pressure relief capacity is significantly enhanced. This is because the 0.16-0.08 mm wedge gap group has a converging effect on the interfacial airflow, thereby generating a vertical dynamic pressure component in the airflow and improving the pressure relief effect. Comparing the gas leakage and average interfacial pressure under the two wedge gaps with a 0.12 mm height gap of the same volume, it can be seen that the wedge gap leads to an increase in gas leakage, while the converging wedge gap has the highest gas leakage. The gas leakage at the interfaces of the 0.16mm-0.08mm and 0.08-0.16mm gaps increased by 24.7% and 10.0% respectively compared to the 0.12mm uniform gap interface. The average pressure diagram shows that the converging wedge gap significantly improves the pressure relief effect, with the pressure difference increase compared to the 0.12mm average gap interface accounting for 19% of the pressure difference between the set central negative pressure zone and the outside air pressure. The average pressure of the diverging wedge and the equal-height gap is roughly the same. Furthermore, the 0.16mm-0.08mm gap exhibits the largest unit gas pressure relief, demonstrating superior pressure relief performance. Therefore, under the premise of ensuring a complete seal at the lip boundary, the converging wedge gap provides better pressure relief performance.

[0068] Specifically, the influence of the area of ​​the biomimetic pressure relief hole 3 and the interfacial gap on the adsorption performance was obtained through experimental testing. It can be seen that in the group without the biomimetic pressure relief hole 3, there is almost no gas leakage. As the diameter increases, the gas leakage rate gradually increases, and the rate of increase shows a trend of first increasing and then decreasing. Regarding the trend of the adsorption force changing with the hole diameter, compared with the group without the biomimetic pressure relief hole, the adsorption force of the sliding suction cup with a diameter of 0.6 mm decreases less. However, when the diameter continues to increase to 0.8 mm and 1 mm, the adsorption force of the sliding suction cup decreases significantly, and its trend is consistent with the gas leakage rate. The contact force generally decreases with increasing hole diameter. Unlike the adsorption force and leakage rate, the contact force already decreases significantly at a diameter of 0.6 mm. The suction pressure ratio of the sliding suction cup shows a trend of first increasing and then decreasing with the hole diameter, with the sliding suction cup with a biomimetic pressure relief hole diameter of 0.6 mm having the highest suction pressure ratio. The experimental results obtained from the four interface design gaps show that: the diameter of the biomimetic convex hull structure 4 on the lip edge has a significant impact on gas leakage. This is because an excessively large biomimetic convex hull structure 4 leads to an excessive gap between the outer edge of the lip and the wall, reducing the sealing effect and causing a large amount of air to enter from the lip edge; the edge leakage caused by the excessively large biomimetic convex hull structure 4 also leads to a significant reduction in the suction force of the sliding suction cup. Although the 0.3mm diameter biomimetic convex hull structure 4 leads to an increase in gas leakage, its adsorption force is not significantly different from that of the structure without the biomimetic convex hull structure. The presence of the biomimetic convex hull structure 4 can effectively reduce the contact force at the lip edge, playing a better role in pressure relief. However, the pressure relief effect of the large-diameter biomimetic convex hull structure 4, which has a faster gas leakage rate, is not significantly better. This is because the gas flow can be approximately considered incompressible, and when the fluid is in horizontal flow or the height change is negligible, Bernoulli's equation can be expressed as:

[0069] P + ρv² / 2 = constant

[0070] The pressure and velocity of the interfacial fluid are negatively correlated; the pressure is low where the velocity is high, thus reducing the pressure relief effect in the contact area. The biomimetic convex hull structures 4 with diameters of 0.3 mm and 0.5-0.3 mm exhibit higher suction-pressure ratios, while the 0.5-0.3 mm group shows slightly higher suction-climbing efficiency than the 0.3 mm group. In summary, an appropriate diameter for the biomimetic convex hull structure 4 can both prevent significant gas leakage, thus greatly reducing the suction cup's adsorption force, and reduce the contact pressure on the flexible lip 8 of the suction cup, thereby achieving good suction-climbing performance.

[0071] In the description of this invention, it should be noted that the terms "center," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0072] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A bionic wall-climbing sliding suction cup, characterized in that: The invention includes a bionic suction cup module, which includes a negative pressure cavity. The opening side of the negative pressure cavity is provided with a flexible suction cup lip. The flexible suction cup lip can adhere to the wall surface and can change the contact pressure and friction with the wall surface. A drive module, installed inside the negative pressure cavity, is used to drive the bionic suction cup module to move on the wall surface; The load is fixedly installed at the end of the bionic suction cup module away from the flexible lip of the suction cup. The flexible lip of the suction cup has multiple biomimetic pressure relief holes distributed on it. A biomimetic pressure relief valve is located on the outer side of each hole, controlling the gas flow rate. This ensures that the positive pressure at the interface between the flexible lip of the suction cup and the wall is reduced while maintaining a negative pressure within the negative pressure chamber. Multiple biomimetic convex structures are distributed on the inner side of the flexible lip of the suction cup, reducing the actual contact area between the flexible lip and the wall, thereby lowering the equivalent coefficient of friction. Each biomimetic convex structure includes flexible silicone rubber, a fixed mesh, and rigid beads. The rigid beads are embedded in the mesh openings of the fixed mesh and the recess in the lower mold. A casting process is used to bond the fixed mesh to the surface of the flexible silicone rubber, completing the bonding between the rigid beads and the flexible silicone rubber, thus creating the biomimetic convex structure.

2. The bionic wall-climbing sliding suction cup according to claim 1, characterized in that: The negative pressure cavity is connected to a high-pressure pneumatic tube, which is used to connect an external vacuum pumping device.

3. The bionic wall-climbing sliding suction cup according to claim 2, characterized in that: The biomimetic pressure relief hole has an elliptical cross-section; the outer ring of the biomimetic pressure relief hole is provided with a groove, which is opened on the side of the flexible lip of the suction cup away from the wall, and the groove and the channel of the biomimetic pressure relief hole form the biomimetic pressure relief hole valve.

4. The bionic wall-climbing sliding suction cup according to claim 1, characterized in that: The drive module includes a motor, which is fixed to the bottom of the negative pressure chamber via a motor mount. One end of the motor is provided with a guide wheel, which is movably mounted to the bottom of the negative pressure chamber via a guide wheel support. The other end of the motor is provided with a drive shaft, which is mounted on a drive wheel support via bearings. The drive wheel support is fixed to the bottom of the negative pressure chamber. Drive wheels are mounted at both ends of the drive shaft. A bevel gear mounted on the output shaft of the motor meshes with a bevel gear fixedly mounted on the drive shaft for transmission.

5. The bionic wall-climbing sliding suction cup according to claim 4, characterized in that: The drive wheel includes a hub, which is connected to one end of the drive shaft via a flange coupling, and the hub is covered with a friction-enhancing rubber skin.

6. The biomimetic wall-climbing sliding suction cup according to claim 1, characterized in that: The flexible lip of the suction cup is made using an upper mold, a middle mold, and a lower mold, combined with 3D technology and a casting process; the biomimetic pressure relief hole is obtained by direct casting through a double-layer concentric cylinder of the upper mold.

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