An amphibious robot with a tilting axis and a control method

Abstract

The present invention belongs to the field of amphibious robots and discloses an amphibious robot with a tilt axis and a control method. The robot comprises a housing, paddle wheels, a tilt axis module, and a control system. The two tilt axis modules are symmetrically distributed on the left and right sides of the housing. The two ends of the tilt axis modules extend from the inside of the housing to the outside of the housing. The paddle wheels are mounted on both ends of the tilt axis modules. The direction of the paddle wheel axis is perpendicular to the direction of the tilt axis axis. The control system is mounted in the housing. The tilt axis module is electrically connected to the control system. The control system controls the rotation of the tilt axis module, thereby changing the direction of the paddle wheels. The present invention utilizes a single tilt mechanism to simultaneously meet the drive modes required for three environments: land, water, and underwater, reducing the weight of the entire robot. All drive modes are achieved by deformation of a single mechanism. The structure is simple and compact, achieving lightweight and miniaturized robots.

Description

Technical Field

[0001] The present invention belongs to the field of amphibious robots, and in particular relates to an amphibious robot with a tilt axis and a control method thereof. Background Art

[0002] Amphibious robots are capable of moving in both land and water environments, and can perform a variety of tasks in both water and land environments. Research on amphibious robots that can adapt to various terrains is of great significance to economic development, environmental monitoring, resource exploration, and military missions.

[0003] Existing amphibious robots are primarily categorized based on their terrestrial locomotion mechanisms into wheeled, legged, and snake-like types. Wheeled robots have a simple walking mechanism, good energy efficiency, and high speed, but their locomotion is relatively simple, resulting in poor obstacle traversal and multi-terrain capabilities. Legged amphibious robots, with their multi-degree-of-freedom articulated legs, can easily traverse obstacles and navigate complex terrain, but they are slow, complex to control, and have low energy efficiency. Snake-like amphibious robots require less space for movement, can navigate narrow terrain, and can be used for disaster relief in specialized environments, but they are prone to malfunction in harsh environments. Common underwater propulsion methods for amphibious robots include fish-like swing propulsion, water jet propulsion, and propeller propulsion. Fish-like robots have complex structures and low efficiency; water jet propulsion is difficult to precisely control its parameters; and propeller propulsion is simple but lacks agility in water.

[0004] The Shenyang Institute of the Chinese Academy of Sciences once combined a propeller for underwater propulsion and a wheeled structure commonly used on land to develop a paddle-type amphibious robot. The outer edge of the robot's wheel is a discontinuous structure, which plays the role of a leg on land. In the marine environment, the paddle legs can provide the robot with sufficient thrust to realize the robot, and the robot's snorkeling is achieved by setting a guide plate in the middle of the robot; Patent No. 202010893885.8 discloses a paddle-legged deformable amphibious hexapod robot with six paddle legs symmetrically distributed at the front, middle and rear of the chassis. It can be driven circumferentially as a compliant leg-type drive mechanism on land, and driven axially as a propeller-type propeller underwater.

[0005] While these types of amphibious robots combine the advantages of each type through an integrated structure, it is difficult to use a simple mechanism to simultaneously enable amphibious robots to move on land, on the surface, and underwater. To address these shortcomings, it is necessary to design and develop an amphibious robot with a simple structure and good movement performance on land, on the surface, and underwater. Summary of the Invention

[0006] The object of the present invention is to provide an amphibious robot with a tilt axis and a control method to solve the above-mentioned technical problems.

[0007] To solve the above technical problems, the specific technical solutions of the present invention for an amphibious robot with a tilt axis and a control method are as follows:

[0008] An amphibious robot with a tilt axis includes a shell, a paddle wheel, a tilt axis module, and a control system. The two tilt axis modules are symmetrically distributed on the left and right sides of the shell. The two ends of the tilt axis module extend from the inside of the shell to the outside of the shell. The paddle wheels are installed at both ends of the tilt axis module. The direction of the paddle wheel axis is perpendicular to the direction of the tilt axis axis. The control system is installed in the shell. The tilt axis module is electrically connected to the control system. The control system controls the rotation of the tilt axis module, thereby changing the direction of the paddle wheel.

[0009] Furthermore, the housing includes a shell and a sealing cover above the shell. The shell has axial holes at the four corners for the tilt axis module to pass through. The four axial holes are exactly the same in size and shape. The inner wall of the axial hole is provided with a sealing circular groove, and the sealing circular groove has an O-type rubber ring.

[0010] Furthermore, the inner wall of the shaft hole has two layers of sealing circular grooves, and the sealing circular grooves have O-type rubber rings in them, forming a two-layer sealing ring structure.

[0011] Furthermore, the upper opening of the shell has two layers of rounded quadrilateral grooves, and the rounded quadrilateral grooves have rubber rings in them.

[0012] Furthermore, the tilt axis module includes an outer rotor motor, a tilt axis, a worm gear, a worm 34, a coupling, a stepper motor, a stepper motor bracket and a stepper motor cover; the two stepper motor brackets are fixedly installed on the left and right sides of the bottom of the shell, the stepper motor cover and the stepper motor bracket jointly fix the stepper motor, the stepper motor is connected to the worm through a coupling, the worm is located above the worm gear and mechanically cooperates with the worm gear, the worm gear is fixedly installed in the middle of the tilt axis through a top screw, the two ends of the tilt axis extend out of the shell from the shaft hole of the shell, the tilt axis and the shell are not in direct contact, the tilt axis and the shaft hole are dynamically sealed by an O-ring rubber ring, the two ends of the tilt axis are fixedly connected to the outer rotor motor, and the outer rotor motor is connected to the control system signal.

[0013] Furthermore, the outer rotor motor has its own angular displacement sensor, which is connected to the control system 5. The control system controls the outer rotor motor through PID.

[0014] Furthermore, the tilting axis includes a worm gear shaft, an optical axis and a motor fixed shaft, both ends of the worm gear shaft are fixedly connected to the optical axis, the optical axis is fixedly connected to the motor fixed shaft, the motor fixed shaft is fixedly connected to the outer rotor motor, the rotor of the outer rotor motor is fixedly connected to the paddle wheel, the motor fixed shaft is hollow for the wire to pass through, and the optical axis has a lead through hole for the wire to pass through.

[0015] Furthermore, the copper ring carbon brush device includes a copper ring, an insulating ring, a copper pin, a carbon brush bracket, a carbon brush cover, a carbon rod, a spring and a conductive copper sheet; the copper ring is sleeved outside the optical axis and fixedly connected to the optical axis, the inner wall of the copper ring has a protruding copper pin, and the carbon brush bracket has a limiting groove, and the limiting groove is sequentially installed with a carbon rod, a spring and a conductive copper sheet from the outside to the inside, the carbon rod is tangentially in close contact with the copper ring, the spring is installed between the carbon rod and the conductive copper sheet, the conductive copper sheet and the carbon rod are connected by a wire, the conductive copper sheet is electrically connected to the control system, the carbon brush cover is fixedly installed on the carbon brush bracket, and the wire of the outer rotor motor passes through the fixed shaft of the motor and passes through the through hole on the optical axis and is fixedly connected to the copper pin in the copper ring.

[0016] Furthermore, the paddle wheel includes a first paddle wheel, a second paddle wheel, a third paddle wheel and a fourth paddle wheel. The spokes of the first paddle wheel and the second paddle wheel are right-handed propeller blades, and the spokes of the third paddle wheel and the fourth paddle wheel are left-handed propeller blades. The axle of each paddle wheel is a cylindrical box body, the outer edge of the paddle wheel is a discontinuous structure, and the rim of the blade end of each paddle wheel is 40 mm wide.

[0017] The present invention also discloses a control method for an amphibious robot with a tilt axis, comprising the following steps:

[0018] Step 1: The first and second paddle wheels enter the water first, and the robot is in a negative buoyancy state;

[0019] Step 2: When the paddle wheels are gradually immersed in water until they are completely submerged, the control system controls the tilt axis by controlling the rotation of the stepper motor, causing the tilt axes on both sides to tilt outward at the same time; at this time, the paddle wheel rotating blades generate thrust diagonally upward. The vertical component of the thrust causes the robot to float in the water, and the horizontal component of the force is in the opposite direction because the paddle wheel blades have opposite spiral directions. Ultimately, the torque generated by the four paddle wheels causes the robot to rotate counterclockwise;

[0020] Step 3: When the body rotates 90 degrees, the control system controls the outer rotor motors of the third and fourth paddle wheels to reverse, and the forward movement direction of the robot is collinear with the long side of the shell.

[0021] The amphibious robot with a tilt axis and the control method of the present invention have the following advantages:

[0022] The amphibious robot of the present invention is in a negative buoyancy state after entering the water. The wide rim at the end of the paddle wheel blade can provide it with sufficient friction when entering the boundary area between the sea and the land, so that it will not be pushed back to the land by the waves.

[0023] After the present invention enters the shallows, the two sets of paddle wheels that enter the water one after another generate lateral thrusts in opposite directions due to the opposite rotation directions of the propellers. The robot automatically rotates the body under the action of the torque, so that the long side of the body is the forward direction, thereby completing the entry into the water.

[0024] When the present invention is underwater, the robot changes the direction of the thrust generated by the paddle wheel by tilting the tilt axis, can easily move in all directions in three-dimensional space, and has high flexibility.

[0025] The present invention introduces the wires of the outer rotor motor through the tilting shaft into the housing, and cooperates with the copper ring carbon brush device to solve the problem of wire entanglement when the tilting module is tilted.

[0026] The present invention utilizes a single tilting mechanism to simultaneously meet the driving modes required for three environments: land, water surface, and underwater, thereby reducing the weight of the entire machine. All driving modes are realized by the deformation of a single mechanism, with a simple and compact structure, thus achieving lightweight and miniaturization of the robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a diagram showing the overall structure of the amphibious robot with a tilt axis according to the present invention;

[0028] Figure 2 This is a position diagram of the tilt axis module, copper ring carbon brush device and control system of the present invention;

[0029] Figure 3 This is a structural diagram of the housing of the present invention;

[0030] Figure 4 A diagram showing the relative position of the paddle wheel relative to the housing of the present invention;

[0031] Figure 5 This is a structural diagram of the tilt axis module of the present invention;

[0032] Figure 6 This is a structural diagram of the tilt axis of the present invention;

[0033] Figure 7 This is a diagram of a copper ring carbon brush device of the present invention;

[0034] Figure 8 This is a diagram showing the tilting state of the two tilt axes of the present invention;

[0035] Explanation of the marks in the figure: 1. outer shell; 11. housing; 111. shaft hole; 112. sealing circular groove; 113. rounded quadrilateral groove; 12. sealing cover; 2. paddle wheel; 3. tilt axis module; 31. outer rotor motor; 32. tilt axis; 321. worm gear shaft; 322. optical axis; 323. motor fixed axis; 322. optical axis; 3221. left optical axis; 32211. left optical axis boss 1; 32212. left optical axis boss 2; 3222. right optical axis; 323. motor fixed axis; 3231. left motor fixed axis; 3232. right motor fixed axis; 32221. right optical axis boss 1; 32222. right optical axis boss 2; 324. lead through hole; 33. Worm gear; 34. Worm; 35. Coupling; 36. Stepper motor; 37. Stepper motor bracket; 38. Stepper motor cover; 4. Copper ring carbon brush device; 41. Copper ring; 42. Insulating ring; 43. Copper pin; 44. Carbon brush bracket; 45. Carbon brush cover; 46. Carbon rod; 47. Spring; 48. Conductive copper sheet; 5. Control system. DETAILED DESCRIPTION

[0036] In order to better understand the purpose, structure and function of the present invention, the following is a further detailed description of an amphibious robot with a tilt axis and a control method of the present invention in conjunction with the accompanying drawings.

[0037] like Figure 1 、 Figure 2 As shown, an amphibious robot with a tilt axis according to the present invention includes a housing 1, paddle wheels 2, a tilt axis module 3, a copper ring carbon brush device 4, and a control system 5. Two tilt axis modules 3 are symmetrically distributed on the left and right sides of the housing 1 and are installed in the housing 1 by screws. The two ends of the tilt axis modules 3 extend from the inside of the housing 1 to the outside of the housing 1. The paddle wheels 2 are installed at both ends of the tilt axis modules 3, and the direction of the paddle wheel 2 axis is perpendicular to the axis direction of the tilt axis 32. The control system 5 is installed in the middle of the housing 1. Four copper ring carbon brush devices 4 are installed on the tilt axis modules 3 and are located at the four corners of the housing 1. The tilt axis modules 3 and the copper ring carbon brush devices 4 are electrically connected to the control system 5. The control system 5 is used to control the operation of the tilt axis modules 3.

[0038] like Figure 3As shown, the housing 1 comprises a shell 11 and a sealing cover 12 above the shell. The four corners of the shell 11 have axial holes 111 for the tilt axis modules 3 to pass through. The four axial holes 111 are identical in size and shape. Two circular sealing grooves 112 are provided on the inner walls of the holes. O-rings 13 are installed in these circular sealing grooves 112, forming a two-layer sealing ring structure that enhances the sealing effect. To facilitate the installation and removal of the sealing cover 12 and enhance the sealing effect, two rounded rectangular grooves 113 are provided at the upper opening of the shell 11. Rubber rings are installed in these grooves for static sealing. The sealing cover 12 and the shell 11 are fixed relative to each other with six countersunk bolts. The O-rings 13 are made of silicone, nitrile butadiene, fluorine, and other wear-resistant and corrosion-resistant materials.

[0039] like Figure 5 As shown, the tilt axis module 3 includes an outer rotor motor 31, a tilt axis 32, a worm gear 33, a worm 34, a coupling 35, a stepper motor 36, a stepper motor bracket 37, and a stepper motor cover 38. Two stepper motor brackets 37 are screwed to the left and right sides of the bottom of the housing 11. The stepper motor cover 38 and the stepper motor bracket 37 together secure the stepper motor 36. The stepper motor 36 is connected to the worm 34 via a coupling 35. The worm 34 is located above and mechanically engages with the worm gear 33. The worm gear 33 is fixed to the center of the tilt axis 32 by a set screw. The tilt axis 32 extends out of the housing 11 through the axial hole 111. The tilt axis 32 and the housing 11 do not directly contact each other. The tilt axis 32 and the axial hole 111 are dynamically sealed by an O-ring 13. The tilt axis 32 is fixedly connected to the outer rotor motor 31 at both ends. The outer rotor motor 31 has its own angular displacement sensor, which is signal-connected to the control system 5. The control system 5 controls the outer transmission motor 31 through PID.

[0040] like Figure 6As shown, the tilt axis 32 includes a worm gear shaft 321, an optical axis 322 and a motor fixed axis 323. The optical axis 322 is divided into a left optical axis 3221 and a right optical axis 3222. The motor fixed axis 323 is divided into a left motor fixed axis 3231 and a right motor fixed axis 3232. The two outer rotor motors 31 are fixed on the left motor fixed axis 3231 and the right motor fixed axis 3232 respectively. The hollow space inside the motor fixed axis 323 can allow the wire to pass through. One end of the left motor fixed axis 3231 is connected to the stator of the outer rotor motor 31 by bolts, and the other end is interference connected with the left optical axis 3221. The left optical axis 3221 includes a left optical axis boss 1 32211 and a left optical axis boss 2 32212. The left optical axis boss 1 32211 is installed in the shaft hole 111 of the housing 11. During installation, lubricating oil is applied to the joint between the shaft shoulder of the left optical axis 3221 and the shaft hole. The second left optical axis boss 32212 is connected to the left end of the worm gear shaft 321 via a pin. The right optical axis 3222 is identical to the left optical axis 3221, and the right motor fixed axis 3232 is identical to the left motor fixed axis 3231. The right optical axis 3222 includes a first right optical axis boss 32221 and a second right optical axis boss 32222. The first right optical axis boss 32221 is mounted within the axial hole 111 of the housing 11, and the second right optical axis boss 32222 is connected to the right end of the worm gear shaft 321 via a pin. The second left optical axis boss 32212 and the second right optical axis boss 32222 have lead holes 324 for wires to pass through.

[0041] The left optical axis 322 and the right optical axis 323 are made of 45 steel by CNC machining, and the surface adopts chrome plating technology, with a roughness of no more than 1.5μm, and have the characteristics of high hardness, wear resistance and corrosion resistance.

[0042] like Figure 7As shown, the copper ring carbon brush device 4 includes a copper ring 41, an insulating ring 42, a copper pin 43, a carbon brush holder 44, a carbon brush cover 45, a carbon rod 46, a spring 47, and a conductive copper sheet 48. Each optical axis 322 is sequentially mounted with a copper ring 41, an insulating ring 42, a copper ring 41, an insulating ring 42, and a copper ring 41. The inner wall of the copper ring 41 has a protruding copper pin 43. The three copper rings 41 are fixedly connected to the optical axis 322 via the three copper pins 43. The three copper rings 41 rotate with the optical axis 322. The carbon brush holder 44 is provided with three limiting grooves. Each limiting groove is sequentially mounted with a carbon rod 46, a spring 47, and a conductive copper sheet 48 from the outside to the inside. The carbon rod 46 is tangentially in close contact with the copper ring 41. The spring 47 is mounted between the carbon rod 46 and the conductive copper sheet 48. The conductive copper sheet 48 and the carbon rod 46 are connected by a wire. The conductive copper sheet 48 is electrically connected to the control system 5. The carbon brush cover 45 is screwed onto the carbon brush bracket 44, securing the carbon rod 46. The wires of the outer rotor motor 31 pass through the motor's fixed shaft 323, exit through the through-hole 324 on the optical axis 322, and are fixedly connected to the copper pin 43 in the copper ring 41. When the tilt axis is tilting, the wires of the outer rotor motor 31 connect to the copper ring 41, which in turn maintains contact with the carbon rod 46. The carbon rod 46 is connected to the conductive copper sheet 48, which is electrically connected to the control system. This copper ring carbon brush assembly 4 solves the problem of wire entanglement when the tilt module is tilted.

[0043] Furthermore, after the wires of the outer rotor motor 31 pass through the tilt shaft 32 , a sealant should be applied to the gap between the inner hole of the tilt shaft 32 and the wires to achieve a waterproof effect.

[0044] like Figure 4 As shown, the paddle wheel 2 is fixedly connected to the rotor of the outer rotor motor 31. The paddle wheel 2 includes a first paddle wheel 21, a second paddle wheel 22, a third paddle wheel 23 and a fourth paddle wheel 24. The relative positions of the paddle wheels relative to the housing 1 are shown in FIG. Figure 4 As shown, the spokes of the first paddle wheel 21 and the second paddle wheel 22 are right-handed propeller blades, and the spokes of the third paddle wheel 23 and the fourth paddle wheel 24 are left-handed propeller blades. The axle of each paddle wheel 2 is a cylindrical box body, and the rotor of the outer rotor motor 31 is installed inside the paddle wheel 2 box body by bolts. When the rotor of the outer rotor motor 31 rotates, it drives the paddle wheel 2 to rotate; the outer edge portion of the paddle wheel 2 of the present invention is a discontinuous structure, and the rim of the blade end of each paddle wheel 2 is 40mm wide, which plays the role of a leg on land and can provide sufficient support for it on soft beaches, mudflats and seabeds, so that the robot will not sink into the terrain. When on the water surface and underwater, the rotating paddle wheel 2 can provide the robot with sufficient thrust to realize the movement of the robot in the water. Underwater movement includes movement and rotation in all directions in space.

[0045] When the present invention enters the shallows, the first paddle wheel 21 and the second paddle wheel 22 enter the water first, and the robot is in a negative buoyancy state. When the paddle wheel 2 is gradually immersed in the water until it is completely immersed, the control system 5 controls the rotation of the stepper motor 36 to control the tilt axis 32 to tilt the tilt axes 32 on both sides simultaneously. Figure 8 As shown, at this time, the rotating blades of the paddle wheel 2 generate thrust obliquely upward, and the thrust along the vertical upward component makes the robot suspended in the water. The horizontal component is in the opposite direction because the spiral direction of the blades of the paddle wheel 2 is opposite. Finally, the torque generated by the four paddle wheels 2 causes the robot to rotate counterclockwise (looking down from the top of the sealed shell). When the body rotates 90 degrees, the control system 5 controls the outer rotor motor 31 of the third paddle wheel 23 and the fourth paddle wheel 24 to reverse, and the forward movement direction of the robot is collinear with the long side of the shell 1.

[0046] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. An amphibious robot with a tilt axis, comprising a housing (1), a paddle wheel (2), a tilt axis module (3), a copper ring carbon brush device (4) and a control system (5), characterized in that: The two tilt axis modules (3) are symmetrically distributed on the left and right sides of the housing (1), and the two ends of the tilt axis module (3) extend from the inside of the housing (1) to the outside of the housing (1). The paddle wheels (2) are installed at the two ends of the tilt axis module (3), and the wheel axis direction of the paddle wheel (2) is perpendicular to the axis direction of the tilt axis (32). The control system (5) is installed in the housing (1), and four copper ring carbon brush devices (4) are installed on the tilt axis module (3) and are located at the four corners of the housing (1). The tilt axis module (3) and the copper ring carbon brush device (4) are electrically connected to the control system (5). The control system (5) controls the rotation of the tilt axis module (3) to rotate the tilt axis module (3). The tilt axis module (3) includes an outer rotor motor (31), a tilt axis (32), a worm wheel (33), a worm (34), a coupling (35), a stepper motor (36), a stepper motor bracket (37) and a stepper motor cover (38); two stepper motor brackets (37) are fixedly mounted on the left and right sides of the bottom of the housing (11); the stepper motor cover (38) and the stepper motor bracket (37) jointly fix the stepper motor (36); the stepper motor (36) is connected to the worm (34) through the coupling (35); the worm (34) is located above the worm wheel (33) and is mechanically matched with the worm wheel (33). The worm wheel (33) is fixedly mounted on the middle part of the tilting shaft (32) through a top screw, and both ends of the tilting shaft (32) extend out of the housing (11) from the shaft hole (111) of the housing (11). The tilting shaft (32) and the housing (11) are not in direct contact, and the tilting shaft (32) and the shaft hole (111) are dynamically sealed by an O-type rubber ring (13). Both ends of the tilting shaft (32) are fixedly connected to the outer rotor motor (31), and the outer rotor motor (31) is connected to the control system (5) by signal; the tilting shaft (32) includes a worm wheel shaft (321), an optical axis (322) and a motor fixed axis (323), and the worm wheel shaft (32) 1) Both ends are fixedly connected to the optical axis (322), the optical axis (322) is fixedly connected to the motor fixed axis (323), the motor fixed axis (323) is fixedly connected to the outer rotor motor (31), the rotor of the outer rotor motor (31) is fixedly connected to the paddle wheel (2), the inner hollow of the motor fixed axis (323) is for a wire to pass through, and the optical axis (322) has a lead through hole (324) for the wire to pass through; the copper ring carbon brush device (4) includes a copper ring (41), an insulating ring (42), a copper pin (43), a carbon brush bracket (44), a carbon brush cover plate (45), a carbon rod (46), a spring (47) and a conductive copper sheet (48);The copper ring (41) is sleeved outside the optical axis (322) and fixedly connected to the optical axis (322). The inner wall of the copper ring (41) has a protruding copper pin (43). The carbon brush bracket (44) has a limit groove. The limit groove is sequentially installed with a carbon rod (46), a spring (47) and a conductive copper sheet (48) from the outside to the inside. The carbon rod (46) is tangentially in close contact with the copper ring (41). The spring (47) is installed between the carbon rod (46) and the conductive copper sheet (48). The conductive copper sheet (48) and the carbon rod (46) are connected by a wire. The conductive copper sheet (48) is electrically connected to the control system (5). The carbon brush cover (45) is fixedly installed on the carbon brush bracket (44). The wire of the outer rotor motor (31) passes through the motor fixed shaft (323), passes through the through hole (324) on the optical axis (322), and is fixedly connected to the copper pin (43) in the copper ring (41). ; 2. The amphibious robot with a tilt axis according to claim 1, characterized in that: The housing (1) comprises a shell (11) and a sealing cover (12) above the shell. The shell (11) has shaft holes (111) at four corners for the tilt axis module (3) to pass through. The four shaft holes (111) are exactly the same in size and shape. The inner wall of the shaft hole (111) is provided with a sealing circular groove (112), and the sealing circular groove (112) has an O-type rubber ring (13) inside.

3. The amphibious robot with a tilt axis according to claim 2, characterized in that: The inner wall of the shaft hole (111) has two layers of sealing circular grooves (112), and an O-type rubber ring (13) is arranged in the sealing circular groove (112), forming a two-layer sealing ring structure.

4. The amphibious robot with a tilt axis according to claim 2, characterized in that: The upper opening of the shell (11) is provided with two layers of rounded quadrilateral grooves (113), and a rubber ring is provided in the rounded quadrilateral grooves (113).

5. The amphibious robot with a tilt axis according to claim 2, characterized in that: The outer rotor motor (31) is provided with an angular displacement sensor, which is connected to the control system (5) by signal, and the control system (5) controls the outer rotor motor (31) through PID.

6. The amphibious robot with a tilt axis according to claim 1, characterized in that: The paddle wheel (2) comprises a first paddle wheel (21), a second paddle wheel (22), a third paddle wheel (23) and a fourth paddle wheel (24); the spokes of the first paddle wheel (21) and the second paddle wheel (22) are right-handed propeller blades; the spokes of the third paddle wheel (23) and the fourth paddle wheel (24) are left-handed propeller blades; the axle of each paddle wheel (2) is a cylindrical box body; the outer edge portion of the paddle wheel (2) is a discontinuous structure; and the width of the rim of the blade end of each paddle wheel (2) is 40 mm.

7. A control method for an amphibious robot with a tilt axis according to any one of claims 1 to 6, characterized in that: The steps include: Step 1: The first paddle wheel (21) and the second paddle wheel (22) enter the water first, and the robot is in a negative buoyancy state; Step 2: When the paddle wheel (2) is gradually immersed in water until it is completely immersed, the control system (5) controls the rotation of the stepper motor (36) to control the tilt axis (32), so that the tilt axes (32) on both sides tilt outward at the same time; at this time, the paddle wheel (2) rotates the blades to generate thrust upward, and the thrust along the vertical upward component causes the robot to float in the water. The horizontal component of the force is in the opposite direction because the spiral direction of the paddle wheel (2) blades is opposite, and finally the torque generated by the four paddle wheels (2) causes the robot to rotate counterclockwise; Step 3: When the body rotates 90 degrees, the control system (5) controls the outer rotor motors (31) of the third paddle wheel (23) and the fourth paddle wheel (24) to reverse, and the forward motion direction of the robot is collinear with the long side of the housing (1).

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