A bionic water strider robot based on surface tension

Abstract

The invention discloses a bionic water strider robot based on surface tension, including a body, a supporting leg arranged on the body and a driving module arranged on the body, the supporting leg including a housing, a supporting leg pad, a supporting leg connecting shaft, a spring pressure cap, a supporting leg connecting slider and a spring, the housing is fixedly arranged on the body, the supporting leg connecting slider is arranged in the housing, one end of the supporting leg connecting shaft is connected to the supporting leg connecting slider, and the other end is connected to the supporting leg pad, the spring pressure cap is located at the top of the housing, the spring is located in the housing and is between the supporting leg connecting slider and the spring pressure cap. The present invention adopts a gradient rising method to optimize the arrangement of supporting legs, and the data obtained by the optimization method can build a three-dimensional model of annular foot pads, and after spraying a super-hydrophobic coating, the foot pads can provide a supporting force of about 23 grams.

Description

Technical Field

[0001] The present invention relates to the field of bionic robots, and in particular to a bionic water strider robot based on surface tension. Background Art

[0002] Traditional aquatic machines primarily rely on buoyancy to maintain their afloat. However, for small aquatic robots, relying solely on buoyancy is insufficient. Small aquatic robots are small in size, displacing limited amounts of water, and therefore generate less buoyancy. To achieve higher performance, these robots must incorporate more functional modules and energy sources, resulting in a more compact structure. This, in turn, increases the robot's average density to greater than that of water. The simplest and most effective way to keep a robot afloat is to leverage the surface tension of water to provide support and compensate for the lack of buoyancy. Naturally, many animals utilize surface tension to float, such as water striders and water spiders. Water striders can adapt to both relatively calm water surfaces like ponds and rivers and turbulent water like streams, and possess excellent aquatic locomotion. Research has shown that water striders can reach speeds of up to 1.5 m / s and can leap distances of 30 to 40 cm. Therefore, studying the water strider's aquatic floating mechanism provides valuable insights into the structural design of small aquatic robots. Summary of the Invention

[0003] In response to the problems in the specification, the present invention provides a bionic water strider robot based on surface tension with a reasonable structural design.

[0004] The technical solutions of the present invention are as follows:

[0005] A bionic water strider robot based on surface tension is characterized in that it includes a body, a support leg arranged on the body and a drive module arranged on the body, the support leg includes a shell, a support leg pad, a support leg connecting shaft, a spring pressure cap, a support leg connecting slider and a spring, the shell is fixedly set on the body, the support leg connecting slider is set in the shell, one end of the support leg connecting shaft is connected to the support leg connecting slider, and the other end is connected to the support leg pad, the spring pressure cap is set at the top of the shell, and the spring is set in the shell and located between the support leg connecting slider and the spring pressure cap.

[0006] Furthermore, the support leg pad includes a central disc, an annular thin plate, a thin plate connecting piece and a support leg connecting shaft mounting column; the annular thin plates are provided in number and are arranged in sequence along the axial direction and tilted on the periphery of the central disc, and there are inter-plate gaps between adjacent annular thin plates, the thin plate connecting piece connects the central disc with the annular thin plate and the annular thin plates with each other, thereby forming a whole, and the support leg connecting shaft mounting column is provided at the center position of the central disc for connecting the support leg connecting shaft.

[0007] Furthermore, the driving modules are respectively arranged at both sides of the body, and the driving modules include a pump casing, an impeller, an open clamping ring, a transmission shaft, a driving frame, an O-ring, a retaining ring, a coupling, a motor bracket, a reduction motor and a pressure cover; the pump casing is fixedly arranged at the lower part of the driving frame, the pressure cover is fixedly arranged at the upper part of the driving frame, the reduction motor is fixedly arranged at the lower part of the pressure cover, the motor bracket is fixedly arranged on the outside of the reduction motor, the transmission shaft is fixedly arranged at the lower part of the shaft of the reduction motor, and are connected through a coupling, the impeller is movably connected to the bottom of the transmission shaft, the contact point between the transmission shaft and the upper part of the driving frame is fixed by a retaining ring and sealed by an O-ring, and the contact point between the transmission shaft and the lower part of the driving frame is fixed by an open clamping ring.

[0008] Furthermore, the interior of the body is a hollow structure, a body cover is provided on the top, and a sealing ring is provided at the connection between the body and the body cover.

[0009] Furthermore, the cross-sectional shape of the machine body is a regular hexagon, and the number of the supporting legs is seven, six of which are evenly arranged on the outer side of the machine body, and one is arranged at the center of the machine body.

[0010] Furthermore, the equivalent length of the central disc is:

[0011] L0=πa

[0012] Where a is the radius of the disk.

[0013] Furthermore, the equivalent length of the annular thin plate is:

[0014] L i =π(x 1i +x 2i )

[0015] where x 1i Indicates the horizontal coordinate of the inner diameter of the circular thin plate, x 2i represents the horizontal coordinate of the outer diameter of the circular thin plate.

[0016] Furthermore, the inter-plate gap calculation formula is as follows:

[0017]

[0018] where k0, k1, k2.....k n , H0 is a constant, h is the depth of the supporting leg pad in the vertical direction.

[0019] Furthermore, the process of determining the inclination angle of the annular thin plate is as follows:

[0020] 1) Randomly give each slice an inclination angle alf i ,

[0021] 2) Calculate the objective function f;

[0022]

[0023] in:

[0024]

[0025]

[0026]

[0027] L i =π(x 1i +x 2i );

[0028] Where γ represents the surface tension coefficient of the liquid;

[0029] 3) The angle of each slice changes in a direction with a step size Δ toward the increasing direction of the objective function;

[0030] alf i =alf i +Δ

[0031] If the objective function decreases, subtract twice the step size;

[0032] alf i =alf i -2Δ

[0033] 4) Until the objective function reaches its maximum value.

[0034] The beneficial effects of the present invention are:

[0035] 1) By arranging a spring pressure cap on the machine body, and arranging a spring, a support leg connecting slider, a support leg connecting shaft, and an optimal support leg pad under the spring pressure cap, and through the movable connection relationship between the above-mentioned components, the various parts are linked to each other, thereby realizing the function of stable operation at different heights of liquid levels.

[0036] 2) The gradient ascent method was used to optimize the arrangement of the supporting legs. The data obtained through this optimization method was used to build a three-dimensional model of the circular foot pad. After spraying the superhydrophobic coating, the foot pad can provide approximately 23 grams of support force.

[0037] 3) The centrifugal pump drive method can reduce the vibration of the water strider robot, prevent it from being entangled by aquatic plants and debris, and provide sufficient pressure difference to drive the water strider robot through recoil force.

[0038] 4) The bionic water strider robot will generate inertial force when encountering the turbulence of water waves. Adding a spring between the foot pad and the body can minimize the burden on the supporting leg and increase the cushioning of the foot pad. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 - is a schematic diagram of the overall structure of the present invention;

[0040] Figure 2 This is a schematic diagram of the support leg structure of the present invention;

[0041] Figure 3 This is a schematic structural diagram of the driving module of the present invention;

[0042] Figure 4 This is a schematic structural diagram of the support leg pad of the present invention;

[0043] Figure 5 A flowchart for determining the inclination angle of the support leg pad of the present invention;

[0044] Figure 6 This is a diagram showing the optimization results of the support leg pad of the present invention;

[0045] Figure 7 This is a curve diagram of the liquid surface deformation contour between the two supporting legs of the present invention;

[0046] Figure 8 Schematic diagram of the inter-plate gap and depth curve fitting effect of the present invention;

[0047] In the figure: 1. Support leg pad; 101. Center disk; 102. Annular thin plate; 103. Support leg connecting shaft mounting column; 104. Thin plate connecting piece; 2. Connecting support leg connecting shaft; 3. Spring pressure cap; 4. Housing; 5. Machine body; 6. Sealing ring; 7. Machine body cover; 8. Drive module; 801. Pump housing; 802. Impeller; 803. Open clamping ring; 804. Transmission shaft; 805. Drive frame; 806. O-ring; 807. Retaining ring; 808. Coupling; 809. Motor bracket; 810. Reducer motor; 811. Pressure cover; 9. Support leg connecting slider; 10. Spring; 11. Support leg. DETAILED DESCRIPTION

[0048] The present invention will be further described below with reference to the accompanying drawings.

[0049] like Figure 1-8As shown, a bionic water strider robot based on surface tension includes a support leg pad 1, a central disk 101, a circular thin plate 102, a support leg connecting shaft mounting column 103, a thin plate connecting piece 104, a support leg connecting shaft 2, a spring pressure cap 3, a shell 4, a body 5, a sealing ring 6, a body cover 7, a drive module 8, a pump housing 801, an impeller 802, an open clamping ring 803, a transmission shaft 804, a drive frame 805, an O-ring 806, a retaining ring 807, a coupling 808, a motor bracket 809, a reduction motor 810, a pressure cover 811, a support leg connecting slider 9, a spring 10 and a support leg 11.

[0050] The support leg 11 can provide buoyancy for the entire device under the action of water surface tension; the support leg 11 includes a shell 4, a support leg pad 1, a support leg connecting shaft 2, a spring pressure cap 3, a support leg connecting slider 9 and a spring 10. The shell 4 is fixedly set on the body 5, and the support leg connecting slider 9 is set in the shell 4. One end of the support leg connecting shaft 2 is connected to the support leg connecting slider 9, and the other end is connected to the support leg pad 1. The spring pressure cap 3 is arranged at the top of the shell 4, and the spring 10 is arranged in the shell 4 and is located between the support leg connecting slider 9 and the spring pressure cap 3.

[0051] The support leg pad 1 includes a central disc 101, five annular thin plates 102, three thin plate connecting pieces 104 and a support leg connecting shaft mounting column 103; the five annular thin plates 102 are arranged in sequence along the axial direction of the support leg pad 1 on the periphery of the central disc 101, and there is an inter-plate gap between adjacent annular thin plates 102. The thin plate connecting piece 104 connects the central disc 101 with the annular thin plates 102 and the annular thin plates 102 with each other to form a whole. The three thin plate connecting pieces 104 are evenly arranged on the circumferential direction of the central disc 101 and the annular thin plates 102. The support leg connecting shaft mounting column 103 is arranged at the center position of the central disc 101 for connecting the support leg connecting shaft 2.

[0052] The interior of the body 5 is a hollow structure, with a body cover 7 on the top. A sealing ring 6 is provided at the connection between the body 5 and the body cover 7. In this embodiment, the cross-section of the body 5 is a regular hexagon, and the support legs 11 are provided in seven positions, six of which are evenly arranged at the vertices of the regular hexagon, and one is located at the center of the body 5.

[0053] The driving modules 8 are fixedly arranged on the left and right sides of the machine body 5; the left driving module 8 includes a left pump casing 801, a pulsator 802, an open clamping ring 803, a transmission shaft 804, a left driving frame 805, an O-ring 806, a retaining ring 807, a coupling 808, a motor bracket 809, a reduction motor 810, and a pressure cover 811. The left pump casing 801 and the left driving frame 805 are the outer shells of the left driving module 8. The reduction motor 810 is fixedly arranged at the lower part of the pressure cover 811, and the reduction motor 810 is fixedly arranged at the lower part of the pressure cover 811. The transmission shaft 804 is arranged, and the reduction motor 810 is fixed to the transmission shaft 804 through the coupling 808. The reduction motor 810 is fixed to the left driving frame 805 through the motor bracket 809. The impeller 802 is movably connected to the lower part of the transmission shaft 804. The retaining ring 807 is used to fix the transmission shaft 804 and the left driving frame 805. The O-ring 806 is used to seal the transmission shaft 804 and the left driving frame 805. The open clamping ring 803 is used to fix the transmission shaft 804 and the left driving frame 805.

[0054] Working process: The reduction motor 810 in the drive module 8 rotates, driving the transmission shaft 804 through the coupling 808, and then driving the impeller 802 to rotate, providing power. Steering and other operations can be achieved by adjusting the motor speed.

[0055] Design of supporting leg 11:

[0056] In this embodiment, the overall shape of the support leg 11 is bowl-shaped, and is mainly composed of a central disk 101 and an annular thin plate 102 , which can provide more supporting force (buoyancy) and better supporting rigidity.

[0057] In this embodiment, the number of annular thin plates is 5, and the radius of the central disk is 4 mm, that is, the width of the annular thin plates is 4 mm. (n = 5, a = 4)

[0058] The gap x between the annular thin plates is calculated based on the known liquid surface deformation contour curve between the two supporting legs (e.g. Figure 7 As shown), and the equation of the fitting curve is used to obtain the inter-plate gap x; the equation of the fitting curve is as follows:

[0059]

[0060] where k0, k1, k2.....k n, H0 is the fitting constant, h is the depth of the supporting leg pad in the vertical direction (in this embodiment, K0...k5 can be: -3.99578243452320e-5, 8.15428195068729e-6, -2.77599674603976e-8, 9.54462068845590e-11, -2.24028073984167e-13, 3.40431569953474e-16; H0 is 0.00385).

[0061] Because each circular plate in the support leg pad has a different length, and changes in the plate angle cause the distance between the plates to change, resulting in changes in the length of each plate, the objective function cannot be solely based on the support force applied to the support leg pad. Given that the total length of each plate reflects the material consumption when the plate thickness and width are constant, the support force per unit plate length can be used as the objective function for optimization.

[0062] The support force F0 and equivalent length L0 provided by the center disk are:

[0063] F0=ρgπa 2 y0

[0064] L0=πa

[0065] Where y0 is the ordinate of the center disk, and a represents the radius of the center disk.

[0066] The support force F provided by the i-th thin plate i and the equivalent length L i (Plate centerline circumference):

[0067]

[0068]

[0069]

[0070] L i =π(x 1i +x 2i )

[0071] where x 1i 、x 2i Represents the horizontal coordinates of the inner and outer diameters of the annular thin plate, y 1i 、y 2i Represents the vertical coordinates of the upper and lower ends of the circular thin plate; the coordinate origin is located on the horizontal plane of the water surface corresponding to the center position of the central disk.

[0072] The objective function is:

[0073]

[0074] Where n is the number of annular thin plates excluding the central disk.

[0075] The process of determining the inclination angle of the annular thin plate is as follows:

[0076] 1) Randomly give each slice an inclination angle alf i ,

[0077] 2) Calculate the objective function f;

[0078]

[0079] in:

[0080]

[0081]

[0082]

[0083] L i =π(x 1i +x 2i );

[0084] 3) The angle of each thin plate changes in a certain step size Δ in the direction of increasing the objective function;

[0085] alf i =alf i +Δ

[0086] If the objective function decreases, subtract twice the step size;

[0087] alf i =alf i -2Δ

[0088] 4) Until the objective function reaches its maximum value, the inclination angle of each thin plate is obtained.

[0089] When n=5 and a=4, the optimization results are as follows: Figure 6 The data obtained by this optimization method can be used to build a three-dimensional model of the ring-shaped foot pad, whose shape is as shown in Figure 4 As shown. After spraying the super-hydrophobic coating, the foot pads can provide approximately 23 grams of support force. This support pad solution will be used in the Water Strider robot in this embodiment. A conservative estimate of the Water Strider robot's mass is approximately 100 grams. To achieve the design's load-bearing capacity, the robot will use seven support pads to provide support.

Claims

1. A bionic water strider robot based on surface tension, characterized in that: The invention comprises a machine body (5), a supporting leg (11) arranged on the machine body (5) and a driving module (8) arranged on the machine body (5); the supporting leg (11) comprises a shell (4), a supporting leg pad (1), a supporting leg connecting shaft (2), a spring pressure cap (3), a supporting leg connecting slider (9) and a spring (10); the shell (4) is fixedly arranged on the machine body (5); the supporting leg connecting slider (9) is arranged in the shell (4); one end of the supporting leg connecting shaft (2) is connected to the supporting leg connecting slider (9) and the other end is connected to the supporting leg pad (1); the spring pressure cap (3) is arranged on the top of the shell (4); and the spring (10) is arranged in the shell (4) and located between the supporting leg connecting slider (9) and the spring pressure cap (3); The support leg pad (1) comprises a central disc (101), an annular thin plate (102), a thin plate connecting piece (104) and a support leg connecting shaft mounting column (103); a plurality of the annular thin plates (102) are provided and are arranged in sequence along the axial direction at the periphery of the central disc (101), and an inter-plate gap is provided between adjacent annular thin plates (102); the thin plate connecting piece (104) connects the central disc (101) and the annular thin plates (102) and the annular thin plates (102) and the annular thin plates (102) to form a whole; the support leg connecting shaft mounting column (103) is provided at the center of the central disc (101) and is used to connect the support leg connecting shaft (2); The cross-sectional shape of the machine body (5) is a regular hexagon, and the supporting legs (11) are arranged in seven numbers, six of which are evenly arranged on the outer side surfaces of the machine body (5), and one is arranged at the center of the machine body (5).

2. The surface tension-based bionic water strider robot according to claim 1, characterized in that: The driving modules (8) are respectively arranged at positions on both sides of the machine body (5), and the driving modules (8) include a pump housing (801), an impeller (802), an open clamping ring (803), a transmission shaft (804), a driving frame (805), an O-ring (806), a retaining ring (807), a coupling (808), a motor bracket (809), a reduction motor (810) and a pressure cover (811); the pump housing (801) is fixedly arranged at the lower part of the driving frame (805), the pressure cover (811) is fixedly arranged at the upper part of the driving frame (805), and the pressure cover (811) is fixedly arranged at the lower part. A reduction motor (810) is provided, a motor bracket (809) is fixedly provided on the outside of the reduction motor (810), a transmission shaft (804) is fixedly provided on the lower part of the shaft of the reduction motor (810), and the shafts are connected via a coupling (808), a pulsator (802) is movably provided at the bottom of the transmission shaft (804), the contact point between the transmission shaft (804) and the upper part of the driving frame (805) is fixed via a retaining ring (807) and sealed via an O-type sealing ring (806), and the contact point between the transmission shaft (804) and the lower part of the driving frame (805) is fixed via an open clamping ring (803).

3. The bionic water strider robot based on surface tension according to claim 1, characterized in that: The interior of the machine body (5) is a hollow structure, and a machine body cover (7) is provided on the top thereof. A sealing ring (6) is provided at the connection between the machine body (5) and the machine body cover (7).

4. The surface tension-based bionic water strider robot according to claim 1, characterized in that: The equivalent length of the central disk is: L0=πa Where a is the radius of the disk.

5. The bionic water strider robot based on surface tension according to claim 1, characterized in that: The equivalent length of the annular thin plate is: L i =π(x 1i +x 2i ) where x 1i Represents the horizontal coordinate of the inner diameter of the circular thin plate, x 2i represents the horizontal coordinate of the outer diameter of the circular thin plate.

6. The bionic water strider robot based on surface tension according to claim 1, characterized in that: The inter-plate gap calculation formula is as follows: where k0, k1, k2.....k n , H0 is a constant, h is the depth of the supporting leg pad in the vertical direction.

7. The bionic water strider robot based on surface tension according to claim 1, characterized in that: The process of determining the inclination angle of the annular thin plate is as follows: 1) Randomly give each slice an inclination angle alf i , 2) Calculate the objective function f; in: L i =π(x 1i +x 2i ); Where γ represents the surface tension coefficient of the liquid; 3) The angle of each slice changes in a direction with a step size Δ toward the increasing direction of the objective function; alf i =alf i +D If the objective function decreases, subtract twice the step size; alf i =alf i -2Δ 4) Until the objective function reaches its maximum value.

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