Robotic fish with independently adjustable tail fin roll angle and control method thereof

Abstract

The present invention relates to a robotic fish with independently adjustable tail fin roll angle, comprising: a tail fin unit, comprising a front section and a tail section, wherein the rear end of the front section is connected to the front end of the tail section, and the front end of the front section is connected to a roll angle adjustment mechanism; a base plate fixed in a fish body shell, and the roll angle adjustment mechanism is assembled on the base plate through a mounting hole; a positioning plate assembly, used to fix or release one end of the roll angle adjustment mechanism; the roll angle adjustment mechanism, used to drive the tail fin unit to fit a sine wave swing and to change the roll angle of the tail fin unit, the roll angle adjustment mechanism including a power assembly, the output end of which is connected to the front section and the tail section through a connecting rod assembly to form a crank-connecting rod mechanism, thereby adjusting the phase difference between the movement of the front section and the tail section. A control method is also provided, wherein the roll angle adjustment mechanism is used to move and rotate the tail fin unit axially, thereby deflecting the roll angle of the tail fin unit. The adjustable robotic fish of the present application can realize multiple movement modes and has high maneuverability.

Description

Technical Field

[0001] The present invention relates to the field of robotics technology, and in particular to a robotic fish with independently adjustable tail fin roll angle and a control method thereof. Background Art

[0002] Fish exhibit high efficiency and excellent maneuverability in turning, hovering, backing up, and braking. Compared to propeller-propelled ships, fish movements are stealthy and quiet. Research on fish-like robots aims to mimic the movement patterns of fish and develop high-speed, high-performance fish-like robots for underwater operations such as reconnaissance, seabed surveys, and marine fishing.

[0003] Current fish-like robots are primarily categorized into body / tail fin propulsion (BCF) and medial fin / paired fin propulsion (MPF). The BCF mode enables rapid, continuous, and efficient swimming, but its limited pattern prevents complex underwater maneuvers and makes it difficult to maneuver in confined waters. Furthermore, the instantaneous propulsion force in the BCF mode changes over time, resulting in unstable propulsion. The MPF mode offers more stable swimming, but at a slower speed, making it difficult to maintain steady progress in turbulent waters.

[0004] To address the instability of BCF propulsion, some research has used twin-tail fin propulsion, demonstrating that this approach can significantly improve the problem. However, this approach still fails to address the BCF's inherently monotonous swimming pattern and poor maneuverability. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a robotic fish with independently adjustable tail fin roll angle and a control method thereof, aiming to achieve multiple motion modes and improve maneuverability.

[0006] The technical solution adopted in the present invention is as follows:

[0007] On one hand, the present application provides a robotic fish with independently adjustable tail fin roll angle, comprising:

[0008] The tail fin unit includes a front section and a tail section, wherein the rear end of the front section is connected to the front end of the tail section, and the front end of the front section is connected to the roll angle adjustment mechanism;

[0009] A bottom plate is fixed in the fish body shell, and the roll angle adjustment mechanism is assembled on the bottom plate through the mounting holes;

[0010] A positioning plate assembly is disposed in the fish body housing and includes a fixed plate and a movable plate. The fixed plate is provided with an assembly slot. The movable plate is used to cooperate with the assembly slot to open or close it. When the movable plate closes the assembly slot, an assembly cavity is formed for fixing one end of the roll angle adjustment mechanism therein. When the movable plate opens the assembly slot, the roll angle adjustment mechanism can move axially along the mounting hole on the bottom plate and rotate in the assembly slot, thereby changing the roll angle of the tail fin unit.

[0011] A roll angle adjustment mechanism is used to drive the tail fin unit to swing in a sinusoidal manner and to change the roll angle of the tail fin unit. The roll angle adjustment mechanism includes a power assembly, the output end of which is connected to the front section and the rear section through a connecting rod assembly to form a crank-connecting rod mechanism to adjust the phase difference between the front section and the rear section;

[0012] A driving member is provided in the fish body housing and is used to drive the movable plate to move and open or close the assembly slot;

[0013] The fish body shell is used to fit the fish head and the fish body, and is also provided with a control module and a battery module for controlling the operation of the roll angle adjustment mechanism and the driving member.

[0014] Further technical solutions are:

[0015] The roll angle adjustment mechanism comprises a transmission shaft mounting portion, on which a transmission shaft assembly is mounted. The transmission shaft assembly comprises a first shaft segment and a second shaft segment. The inner ends of the first shaft segment and the second shaft segment are meshed and connected by toothed surfaces to form a connected hollow shaft. The outer ends of the first shaft segment and the second shaft segment are eccentrically provided with a first cam and a second cam respectively through a wheel disc with an increased diameter.

[0016] A first crank-connecting rod mechanism is formed between the first cam shaft, the transmission shaft mounting portion and the first section via a first connecting rod assembly;

[0017] A second crank-connecting rod mechanism is formed between the second cam shaft, the transmission shaft mounting portion and the tail section via a second connecting rod assembly. During operation, the hollow shaft can be rotated by the driving device.

[0018] A long bolt is passed through the hollow shaft, and its end is locked to the wheel disc by a locking piece. Loosening the locking piece can release the assembly of the hollow shaft and the long bolt, so that the first shaft section and the second shaft section can rotate relative to each other to adjust the relative position of the first cam shaft and the second cam shaft, thereby adjusting the phase difference between the angle between the first section and the transmission shaft mounting portion and the angle between the tail section and the transmission shaft mounting portion.

[0019] The first connecting rod assembly includes a swing rod, which is arranged along the length direction of the first section and fixedly connected to the first section, one end of the swing rod is engaged with the first convex shaft through a sliding groove, and the other end is hinged to the tail section;

[0020] The second connecting rod assembly includes an L-shaped rod and a transmission rod, one end of the L-shaped rod is engaged with the second protruding shaft through a sliding groove, and the other end is hinged to one end of the transmission rod, and the other end of the transmission rod is hinged to the tail section;

[0021] The transmission rod is arranged in parallel with the swing rod;

[0022] The first positioning shaft and the second positioning shaft are respectively provided at the two ends of the lower side of the transmission shaft mounting portion. One end of the first positioning shaft is hinged to the middle part of the swing arm, and the other end is hinged to the first section; one end of the second positioning shaft is hinged to the middle part of the L-shaped rod, and the other end is hinged to the first section.

[0023] The structure of the roll angle adjustment mechanism also includes a motor mounting portion, in which a motor is mounted, and an output end thereof is connected to the hollow shaft through a gear transmission assembly; one end of the motor mounting portion is connected to the transmission shaft mounting portion, and the other end is provided with a square platform, and a circular platform is provided on the surface of the square platform.

[0024] The structure of the fixing plate includes an upper positioning plate and a lower positioning plate fixedly connected thereto, the lower surface of the upper positioning plate is provided with a limiting circular groove, a through hole is provided on the groove, the upper side opening of the through hole is located on the upper surface of the upper positioning plate, and a limiting plate is provided above the through hole;

[0025] An octagonal star hole is provided on the lower positioning plate. The octagonal star hole, the limiting circular groove and the through hole are coaxially arranged to form the assembly groove, and the inner diameter of the limiting circular groove is larger than the outer diameter of the octagonal star hole.

[0026] The movable plate is a straight plate, which is used to close or open the upper opening of the through hole, and the assembly cavity is formed after closing.

[0027] The side surface of the mounting hole on the base plate is a wedge-shaped surface, and the roll angle adjustment mechanism is provided with an inclined surface that matches the wedge-shaped surface.

[0028] The present application also provides a control method for a robotic fish with independently adjustable tail fin roll angle as described above, wherein the robotic fish includes a first tail fin unit and a second tail fin unit evenly distributed along the circumferential direction, and a first roll angle adjustment mechanism connected to the first tail fin unit, and a second roll angle adjustment mechanism connected to the second tail fin unit. The control method includes: adjusting the first roll angle adjustment mechanism and / or the second roll angle adjustment mechanism to move axially along the mounting hole and then rotate to deflect the roll angle of the first tail fin unit and / or the second tail fin unit.

[0029] Its further technical solution is:

[0030] The control method further includes: changing the initial connection position of the roll angle adjustment mechanism and the crank-connecting rod mechanism formed by the first section, or / and changing the initial connection position of the crank-connecting rod mechanism formed by the roll angle adjustment mechanism and the tail section, thereby adjusting the angle between the first section and the roll angle adjustment mechanism and the angle between the tail section and the roll angle adjustment mechanism, thereby adjusting the phase difference between the motion of the first section and the tail section, thereby changing the wavelength of the fitted sinusoidal wave oscillating motion.

[0031] The beneficial effects of the present invention are as follows:

[0032] The tail fin units of the present invention achieve roll angle adjustment through an axially movable and rotatable roll angle adjustment mechanism. Each tail fin unit is independently driven by its associated roll angle adjustment mechanism, which can change the positional relationship between the tail fin units, enabling multi-tail coordinated motion and completing complex underwater maneuvers such as propulsion, snorkeling, roll, pitch, and pitch, greatly improving maneuverability.

[0033] For the single tail fin unit of the present invention, the roll angle adjustment mechanism forms a crank-connecting rod mechanism with the first section and the tail section through the connecting rod assembly. The initial connection position of each group of crank-connecting rod mechanisms can be adjusted by adjusting the transmission shaft assembly of the roll angle adjustment mechanism to achieve the phase difference between the first section movement and the tail section movement, and then achieve the adjustment of the wavelength during the fitting sinusoidal wave swinging motion to adapt to the motion requirements of different environments.

[0034] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure of the robotic fish according to Example 1 of the present invention.

[0036] Figure 2 This is a partially exploded schematic diagram of the roll angle adjustment mechanism and the tail fin unit assembly structure of Example 1 of the present invention.

[0037] Figure 3 This is a schematic diagram of the exploded structure of the transmission shaft assembly of the roll angle adjustment mechanism of Example 1 of the present invention.

[0038] Figure 4 This is a schematic diagram of the exploded structure of the positioning plate assembly according to Example 1 of the present invention.

[0039] Figure 5 This is a bottom view of the positioning plate assembly according to embodiment 1 of the present invention.

[0040] Figure 6 This is a schematic diagram of the bottom plate structure of Example 1 of the present invention.

[0041] Figure 7This is a schematic diagram of the exploded structure of the positioning plate assembly, a tail fin unit and a roll angle adjustment mechanism in Example 1 of the present invention.

[0042] Figure 8 Schematic diagram of the motion pattern of the robotic fish during one cycle of propulsion and snorkeling motion under the control method of Example 2 of the present invention.

[0043] Figure 9 Schematic diagram of the motion pattern of the robotic fish during one rolling motion cycle under the control method of Example 2 of the present invention.

[0044] Figure 10 Schematic diagram of the motion pattern of the robotic fish during one cycle of bow rolling motion under the control method of Example 2 of the present invention.

[0045] Figure 11 Schematic diagram of the motion pattern of the robotic fish during one cycle of pitch motion under the control method of Example 2 of the present invention.

[0046] In the figure: 1. Fish body shell; 2. Roll angle adjustment mechanism; 3. Caudal fin unit; 4. Positioning plate assembly; 5. Drive element; 6. Control module; 7. Straight plate; 8. Upper positioning plate; 9. Lower positioning plate; 10. Bottom plate; 11. Battery module; 20. Upper mounting base; 21. Lower mounting base; 101. Mounting hole; 201. Round platform; 202. Square platform; 203. Inclined surface; 204. First shaft segment; 205. Second shaft segment. 206, wheel disc; 207, first cam shaft; 208, second cam shaft; 209, motor; 211, first positioning shaft; 212, second positioning shaft; 213, long bolt; 214, locking piece; 301, first section; 302, tail section; 303, swing rod; 304, L-shaped rod; 305, transmission rod; 801, limiting circular groove; 802, through hole; 803, limiting plate; 901, octagonal star hole; 1011, wedge surface. DETAILED DESCRIPTION

[0047] The specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0048] Example 1

[0049] like Figure 1 As shown, the embodiment of the present application provides a robotic fish with independently adjustable tail fin roll angle, comprising:

[0050] The tail fin unit 3 includes a front section 301 and a tail section 302 , wherein the rear end of the front section 301 is connected to the front end of the tail section 302 , and the front end of the front section 301 is connected to the roll angle adjustment mechanism 2 ;

[0051] The bottom plate 10 is fixed in the fish body shell 1, and the roll angle adjustment mechanism 2 is assembled on the bottom plate 10 through the mounting hole 101;

[0052] The positioning plate assembly 4 is arranged in the fish body shell 1 and includes a fixed plate and a movable plate. The fixed plate is provided with an assembly slot. The movable plate is used to cooperate with the assembly slot to open or close it. When the movable plate closes the assembly slot, an assembly cavity is formed, which is used to fix one end of the roll angle adjustment mechanism 2 therein. When the movable plate opens the assembly slot, the roll angle adjustment mechanism 2 can move axially along the mounting hole 101 on the bottom plate 10 and rotate in the assembly slot, thereby changing the roll angle of the tail fin unit 3;

[0053] The roll angle adjustment mechanism 2 is used to drive the tail fin unit 3 to swing in a sinusoidal manner and change the roll angle of the tail fin unit 3. The roll angle adjustment mechanism 2 includes a power assembly, the output end of which is connected to the first section 301 and the tail section 302 through a connecting rod assembly to form a crank-connecting rod mechanism to adjust the motion phase difference between the first section 301 and the tail section 302;

[0054] The driving member 5 is arranged in the fish body shell 1 and is used to drive the movable plate to move and open or close the assembly slot; the fish body shell 1 is used to fit the fish head and fish body, and is also provided with a control module 6 and a battery module 11 for controlling the operation of the roll angle adjustment mechanism 2 and the driving member 5.

[0055] This embodiment of the robotic fish features independently adjustable tail fin roll angles. The number of tail fin units is adjusted as needed, with two used in this example. Each tail fin unit achieves roll adjustment via an axially movable and rotatable roll angle adjustment mechanism. Changing the roll angle of each tail fin unit alters the strike direction of the tail fin. Each tail fin unit is independently driven by its associated roll angle adjustment mechanism, thereby changing the positional relationship between the units and enabling multi-tail coordinated motion. This allows for complex underwater maneuvers such as propulsion, snorkeling, roll, bow pitch, and pitch, significantly enhancing maneuverability.

[0056] See also Figure 2 , is an exploded schematic diagram of the assembly structure of the roll angle adjustment mechanism and the tail fin unit in the embodiment, Figure 2 (b) is Figure 2 Another perspective of (a). The roll angle adjustment mechanism 2 includes a transmission shaft mounting portion, on which a transmission shaft assembly is mounted. The transmission shaft assembly includes a first shaft segment 204 and a second shaft segment 205. The inner ends of the first and second shaft segments 204 and 205 are meshed with toothed surfaces to form a connected hollow shaft. The outer ends of the first and second shaft segments 204 and 205 are eccentrically provided with a first protruding shaft 207 and a second protruding shaft 208, respectively, via a wheel disc 206 with an increased diameter.

[0057] A first crank-connecting rod mechanism is formed between the first protruding shaft 207, the transmission shaft mounting portion, and the first section 301 via a first connecting rod assembly. Specifically, the first connecting rod assembly includes a swing rod 303, which is arranged along the length direction of the first section 301 and is fixedly connected to the first section 301. One end of the swing rod 303 engages with the first protruding shaft 207 via a sliding groove, and the other end is hinged to the tail section 302. The first section 301 and the swing rod 303 can be fixedly connected by a bolt pair.

[0058] A second connecting rod assembly forms a second crank-connecting rod mechanism between the second protruding shaft 208, the drive shaft mounting portion, and the tail section 302. During operation, the hollow shaft is driven by the drive device to rotate. Specifically, the second connecting rod assembly includes an L-shaped rod 304 and a drive rod 305. One end of the L-shaped rod 304 engages with the second protruding shaft 208 via a slot, and the other end is hinged to one end of the drive rod 305. The other end of the drive rod 305 is hinged to the tail section 302.

[0059] The transmission rod 305 is arranged parallel to the swing rod 303;

[0060] A first positioning shaft 211 and a second positioning shaft 212 are respectively provided at the two ends of the lower side of the transmission shaft mounting portion. One end of the first positioning shaft 211 is hinged to the middle part of the swing rod 303, and the other end is hinged to the first section 301; one end of the second positioning shaft 212 is hinged to the middle part of the L-shaped rod 304, and the other end is hinged to the first section 301.

[0061] Specifically, the L-shaped rod 304 includes a long section and a short section, and the tail section 302 extends out at the hinged position with the transmission rod 305 to a length that is the same as the short section of the L-shaped rod 304 .

[0062] The structure of the roll angle adjustment mechanism 2 also includes a motor mounting portion, in which a motor 209 is mounted, and its output end is connected to the hollow shaft through a gear transmission assembly; one end of the motor mounting portion is connected to the transmission shaft mounting portion, and the other end is provided with a square platform 202, and the surface of the square platform 202 is provided with a circular platform 201. The square platform 202 and the circular platform 201 are arranged to cooperate with the assembly groove to achieve fixation or axial movement of the roll angle adjustment mechanism. The specific cooperation method is described below.

[0063] Specifically, the motor mounting portion is an upper mounting seat 20 , which forms a cavity for mounting the motor. A groove is provided on the side wall of the cavity for extending the motor shaft. The square platform 202 and the circular platform 201 are located at the top of the upper mounting seat 20 .

[0064] Specifically, the transmission shaft mounting portion is a mounting cavity formed by connecting the upper mounting seat 20 and the lower mounting seat 21, in which the hollow shaft is mounted through a bearing. The first positioning shaft 211 and the second positioning shaft 212 are fixedly mounted on both ends of the lower surface of the lower mounting seat 21.

[0065] See also Figure 3 A long bolt 213 is passed through the hollow shaft, and its end is locked with the wheel disc 206 by a locking piece 214. Loosening the locking piece 214 can release the assembly of the hollow shaft and the long bolt 213, so that the first shaft section 204 and the second shaft section 205 can rotate relative to each other to adjust the relative position of the first protruding shaft 207 and the second protruding shaft 208, thereby adjusting the phase difference between the angle between the first section 301 and the transmission shaft mounting portion and the angle between the tail section 302 and the transmission shaft mounting portion.

[0066] Specifically, the toothed surfaces provided on the inner ends of the first and second shaft segments are distributed circumferentially, meshing with each other via the toothed surfaces. During installation, these surfaces are ensured to be the force-bearing surfaces for transmission. To adjust the initial connection position between the roll angle adjustment mechanism and the tail fin unit, the locking member is loosened and the long bolt is pulled out, releasing the assembly with the hollow shaft and the meshing connection between the two shaft segments. The first or second shaft segment is then rotated in the meshing direction, changing the position of the first protruding shaft 207 on the outer end wheel of the shaft segment relative to the second protruding shaft 208. Once the adjustment is complete, the two shaft segments are reassembled using the long bolt and locking member, and the robotic fish can resume normal operation.

[0067] It can be understood that for a single tail fin unit of the present embodiment, since the roll angle adjustment mechanism forms a crank-connecting rod mechanism with the head section and the tail section through a connecting rod assembly respectively, the initial connection position of each group of crank-connecting rod mechanisms can be adjusted by adjusting the transmission shaft assembly of the roll angle adjustment mechanism. Since the position of the first protrusion 207 relative to the second protrusion 208 is changed, the initial connection position of the two groups of crank-connecting rod mechanisms is changed, that is, the angle of the L-shaped rod 304 relative to the swing rod 303 is changed, thereby realizing the adjustment of the motion phase difference between the head section 301 and the tail section 302, thereby realizing the adjustment of the wavelength during the fitting sinusoidal wave swing motion to adapt to the motion requirements of different environments.

[0068] See also Figure 4 and Figure 5 The structure of the fixed plate of the positioning plate assembly 4 is specifically as follows: it includes an upper positioning plate 8 and a lower positioning plate 9 fixedly connected to it, the lower surface of the upper positioning plate 8 is provided with a limiting circular groove 801, on which a through hole 802 is provided, the upper side opening of the through hole 802 is located on the upper surface of the upper positioning plate 8, and a limiting plate 803 is provided above the through hole 802; an octagonal star hole 901 is provided on the lower positioning plate 9, and the octagonal star hole 901, the limiting circular groove 801 and the through hole 802 are coaxially arranged to constitute the assembly groove, and the inner diameter of the limiting circular groove 801 is larger than the outer diameter of the octagonal star hole 901.

[0069] The movable plate is preferably a straight plate 7, which is used to close or open the upper opening of the through hole 802, and an assembly cavity is formed after closing.

[0070] The driving member 5 connected to the straight plate 7 is preferably a steering gear, and its output shaft is connected to the center of the straight plate 7.

[0071] It can be understood that since two tail fin units are provided in this embodiment, two assembly grooves are correspondingly provided, respectively for installing two roll angle adjustment mechanisms, and the two assembly grooves are symmetrically distributed with the servo output shaft as the center.

[0072] Specifically, such as Figure 6 As shown, the side surface of the mounting hole 101 on the base plate 10 is a wedge-shaped surface 1011, and the roll angle adjustment mechanism 2 is provided with an inclined surface 203 that cooperates with the wedge-shaped surface 1011. The cooperation between the wedge-shaped surface and the inclined surface can limit the roll angle adjustment mechanism 2 so that its axial movement can only be upward, not downward.

[0073] See also Figure 7 The specific matching mode between the aforementioned assembly groove and the end of the roll angle adjustment mechanism in this embodiment is as follows:

[0074] When the robotic fish is operating normally, the straight plate 7 blocks the upper opening of the assembly groove (i.e., the upper opening of the through hole 802), forming an assembly cavity. The square platform 202 and the circular platform 201 on the top of the roll angle adjustment mechanism 2 extend into the assembly cavity. The square platform 202 is embedded in the octagonal star hole 901 and is restricted from circumferential rotation. The circular platform 201 extends into the through hole 802, and the top surface of the circular platform 201 is in contact with the bottom surface of the straight plate 7, and its position is restricted by the straight plate 7. At this time, the roll angle adjustment mechanism 2 is fixed in the mounting hole 101 of the base plate 10.

[0075] When the roll angle of a tail fin unit of the robotic fish needs to be adjusted, the driving member 5 is actuated to drive the straight plate 7 to rotate so that its two ends open the upper opening of the assembly slot (see Figure 4 (The state shown in the figure) At this time, the roll angle adjustment mechanism 2 is lifted upward along the axial direction of the mounting hole 101, and the circular platform 201 moves upward along the through hole 802. The top surface of the circular platform 201 is limited by the limit baffle 803 to control its upward movement. At the same time, the square platform 202 breaks away from the circumferential limit of the octagonal star hole 901 and enters the limit circular groove 801. Since its inner diameter is larger than the outer diameter of the octagonal star hole 901, it does not limit the square platform 202. The roll angle adjustment mechanism 2 is rotated to adjust the roll angle of the tail fin unit, and any angle can be adjusted. After the adjustment is completed, the roll angle adjustment mechanism 2 is moved downward along the axial direction of the mounting hole 101. The driving member 5 is activated, driving the straight plate 7 to rotate until the upper opening of the assembly groove is closed again, and the roll angle adjustment mechanism 2 is fixed.

[0076] Specifically, the control module 6 and the battery module 11 are fixedly arranged in the fish body shell 1 through the mounting plate; the driving member 5 is fixedly arranged in the fish body shell 1 through the mounting plate.

[0077] Example 2

[0078] The present application also provides a control method for a robotic fish with independently adjustable tail fin roll angles as described in Example 1. The robotic fish includes a first tail fin unit and a second tail fin unit uniformly distributed along the circumferential direction, and a first roll angle adjustment mechanism connected to the first tail fin unit and a second roll angle adjustment mechanism connected to the second tail fin unit. The control method includes: the first roll angle adjustment mechanism and / or the second roll angle adjustment mechanism are moved axially along the mounting hole of the bottom plate and then rotated to deflect the roll angle of the first tail fin unit and / or the second tail fin unit. This changes the positional relationship between the two tail fin units and realizes multi-tail collaborative motion: completing complex underwater actions such as propulsion, snorkeling, rolling, bow pitch, and pitching, see [1]. Figures 8-11 .

[0079] like Figure 8 As shown, the motors of the two tail fin units are driven synchronously, ensuring a zero phase difference between the two tail fins. A roll angle adjustment mechanism maintains the roll angles of both tail fin units at zero. The two tail fins simultaneously expand and contract outward and inward. When the robot fish's bow and stern are horizontal, it can achieve propulsion; when the bow and stern are vertical, it can achieve snorkeling. Figure 8 (a) to (d) are schematic diagrams of one movement cycle of the robotic fish tail fin. Figure 8 (a) The tail fin stretches outward; Figure 8 (b) The tail fin is stretched to its limit, at which point the angle between the first segment of the tail fin and the fish body is the largest; Figure 8 (c) The tail fin retracts inward; Figure 8 (d) The tail fin is contracted to the limit, at which point the angle between the first section of the tail fin and the fish body is the smallest. Figure 8 (a)' to (d)' are the left views of (a) to (d) respectively.

[0080] like Figure 9 As shown, the motors of the two tail fins are driven synchronously to ensure a phase difference of zero between them. Using the roll angle adjustment mechanism, the roll angles of the two tail fin units are deflected 90° in the same direction from the zero position. The two tail fins simultaneously expand and contract inward, allowing the robotic fish to achieve rolling motion. Figure 9 (a) to (d) are schematic diagrams of one movement cycle of the robotic fish tail fin. Figure 9 (a) The tail fin stretches outward; Figure 9 (b) The tail fin is stretched to its limit, at which point the angle between the first segment of the tail fin and the fish body is the largest; Figure 9 (c) The tail fin retracts inward; Figure 9 (d) The tail fin is contracted to the limit, at which point the angle between the first section of the tail fin and the fish body is the smallest. Figure 9 (a)' to (d)' are the left views of (a) to (d) respectively.

[0081] like Figure 10As shown, the motors of the two tail fins are driven synchronously to ensure a phase difference of zero between them. Using a roll angle adjustment mechanism, the roll angle of one tail fin unit is maintained at zero, while the roll angle of the other tail fin unit is rotated 180° from zero. The two tail fins simultaneously expand and contract inward, allowing the robotic fish to achieve bow rolling motion. Figure 10 (a) to (d) are schematic diagrams of one movement cycle of the robotic fish tail fin. Figure 10 (a) The tail fin stretches outward; Figure 10 (b) The tail fin is stretched to its limit, at which point the angle between the first segment of the tail fin and the fish body is the largest; Figure 10 (c) The tail fin retracts inward; Figure 10 (d) The tail fin is contracted to the limit, at which point the angle between the first section of the tail fin and the fish body is the smallest. Figure 10 (a)' to (d)' are the left views of (a) to (d) respectively.

[0082] like Figure 11 As shown, the motors of the two tail fins are driven synchronously to ensure a phase difference of zero between them. Using the roll angle adjustment mechanism, the roll angles of the two tail fin units are deflected by 90° and -90°, respectively, from their respective zero positions. The two tail fins simultaneously expand and contract inward, allowing the robotic fish to achieve pitching motion. Figure 11 (a) to (d) are schematic diagrams of one movement cycle of the robotic fish tail fin. Figure 11 (a) The tail fin stretches outward; Figure 11 (b) The tail fin is stretched to its limit, at which point the angle between the first segment of the tail fin and the fish body is the largest; Figure 11 (c) The tail fin retracts inward; Figure 11 (d) The tail fin is contracted to the limit, at which point the angle between the first section of the tail fin and the fish body is the smallest. Figure 11 (a)' to (d)' are the left views of (a) to (d) respectively.

[0083] The control method further includes: changing the initial connection position of the crank-connecting rod mechanism formed by the roll angle adjustment mechanism 2 and the first section 301, or / and changing the initial connection position of the crank-connecting rod mechanism formed by the roll angle adjustment mechanism 2 and the tail section 302, so as to adjust the phase difference between the movement of the first section 301 relative to the roll angle adjustment mechanism 2 and the movement of the tail section 302 relative to the roll angle adjustment mechanism 2, thereby adjusting the wavelength of the sinusoidal wave oscillating motion.

[0084] This embodiment adopts dual-tail collaborative propulsion and makes the tail fin unit independent, which can flexibly adjust the tail fin swing frequency, swing amplitude, phase difference and striking direction and other movement characteristics. Through the vector propulsion of dual-tail collaboration, it can realize various underwater movement modes and improve maneuverability.

[0085] Those skilled in the art will understand that the foregoing descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will be able to modify the technical solutions described in the foregoing embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A robotic fish with independently adjustable tail fin roll angle, characterized in that: include: The tail fin unit (3) comprises a front section (301) and a tail section (302), wherein the rear end of the front section (301) is connected to the front end of the tail section (302), and the front end of the front section (301) is connected to the roll angle adjustment mechanism (2); A bottom plate (10) is fixedly mounted in the fish body housing (1), and the roll angle adjustment mechanism (2) is mounted on the bottom plate (10) through a mounting hole (101); A positioning plate assembly (4) is arranged in the fish body shell (1), comprising a fixed plate and a movable plate, wherein the fixed plate is provided with an assembly slot, and the movable plate is used to cooperate with the assembly slot to open or close it, and when the movable plate closes the assembly slot, an assembly cavity is formed, which is used to fix one end of the roll angle adjustment mechanism (2) therein, and when the movable plate opens the assembly slot, the roll angle adjustment mechanism (2) can move axially along the mounting hole (101) on the bottom plate (10) and rotate in the assembly slot, thereby changing the roll angle of the tail fin unit (3); A roll angle adjustment mechanism (2) is used to drive the tail fin unit (3) to swing in a sinusoidal manner and to change the roll angle of the tail fin unit (3). The roll angle adjustment mechanism (2) includes a power assembly, the output end of which forms a crank-connecting rod mechanism with the first section (301) and the tail section (302) through a connecting rod assembly, thereby adjusting the motion phase difference between the first section (301) and the tail section (302); A driving member (5) is provided in the fish body housing (1) and is used to drive the movable plate to move and open or close the assembly slot; The fish body housing (1) is used to fit the fish head and the fish body, and is further provided with a control module (6) and a battery module (11) therein for controlling the operation of the roll angle adjustment mechanism (2) and the driving member (5).

2. The robotic fish with independently adjustable tail fin roll angle according to claim 1, characterized in that: The roll angle adjustment mechanism (2) comprises a transmission shaft mounting portion, on which a transmission shaft assembly is mounted, the transmission shaft assembly comprising a first shaft segment (204) and a second shaft segment (205), wherein the inner ends of the first shaft segment (204) and the second shaft segment (205) are meshedly connected via toothed surfaces to form a connected hollow shaft, and the outer ends are eccentrically provided with a first convex shaft (207) and a second convex shaft (208) via a wheel disc (206) with an increased diameter. A first crank-connecting rod mechanism is formed between the first convex shaft (207), the transmission shaft mounting portion and the first section (301) via a first connecting rod assembly; A second crank-connecting rod mechanism is formed between the second convex shaft (208), the transmission shaft mounting portion and the tail section (302) via a second connecting rod assembly. During operation, the hollow shaft can rotate under the drive of the driving device.

3. The robotic fish with independently adjustable tail fin roll angle according to claim 2, characterized in that: A long bolt (213) is passed through the hollow shaft, and the end of the long bolt (213) is locked with the wheel disc (206) by a locking member (214). The assembly of the hollow shaft and the long bolt (213) can be released by loosening the locking member (214), so that the first shaft section (204) and the second shaft section (205) can be rotated relative to each other to adjust the relative position of the first cam shaft (207) and the second cam shaft (208), thereby adjusting the phase difference between the angle between the first section (301) and the transmission shaft mounting portion and the angle between the tail section (302) and the transmission shaft mounting portion.

4. The robotic fish with independently adjustable tail fin roll angle according to claim 2, characterized in that: The first connecting rod assembly includes a swing rod (303) which is arranged along the length direction of the first section (301) and is fixedly connected to the first section (301); one end of the swing rod (303) is engaged with the first convex shaft (207) through a sliding groove, and the other end is hinged to the tail section (302); The second connecting rod assembly includes an L-shaped rod (304) and a transmission rod (305), one end of the L-shaped rod (304) cooperates with the second convex shaft (208) through a sliding groove, and the other end is hinged to one end of the transmission rod (305), and the other end of the transmission rod (305) is hinged to the tail section (302); The transmission rod (305) is arranged in parallel with the swing rod (303); A first positioning shaft (211) and a second positioning shaft (212) are respectively provided at both ends of the lower side of the transmission shaft mounting portion. One end of the first positioning shaft (211) is hinged to the middle of the swing rod (303), and the other end is hinged to the first section (301); one end of the second positioning shaft (212) is hinged to the middle of the L-shaped rod (304), and the other end is hinged to the first section (301).

5. The robotic fish with independently adjustable tail fin roll angle according to claim 2, characterized in that: The structure of the roll angle adjustment mechanism (2) further comprises a motor mounting portion, in which a motor (209) is mounted, and an output end of the motor mounting portion is connected to the hollow shaft through a gear transmission assembly; one end of the motor mounting portion is connected to the transmission shaft mounting portion, and the other end is provided with a square platform (202), and a circular platform (201) is provided on the surface of the square platform (202).

6. The robotic fish with independently adjustable tail fin roll angle according to claim 1, characterized in that: The structure of the fixing plate comprises an upper positioning plate (8) and a lower positioning plate (9) fixedly connected thereto, wherein the lower surface of the upper positioning plate (8) is provided with a limiting circular groove (801), on which a through hole (802) is provided, the upper opening of the through hole (802) is located on the upper surface of the upper positioning plate (8), and a limiting plate (803) is provided above the through hole (802); An octagonal star hole (901) is provided on the lower positioning plate (9), and the octagonal star hole (901), the limiting circular groove (801) and the through hole (802) are coaxially arranged to form the assembly groove, and the inner diameter of the limiting circular groove (801) is larger than the outer diameter of the octagonal star hole (901).

7. The robotic fish with independently adjustable tail fin roll angle according to claim 6, characterized in that: The movable plate is a straight plate (7) used to close or open the upper opening of the through hole (802), and the assembly cavity is formed after closing.

8. The robotic fish with independently adjustable tail fin roll angle according to claim 1, characterized in that: The side surface of the mounting hole (101) on the bottom plate (10) is a wedge-shaped surface (1011), and the roll angle adjustment mechanism (2) is provided with an inclined surface (203) that matches the wedge-shaped surface (1011).

9. A control method for a robotic fish with independently adjustable tail fin roll angle according to any one of claims 1 to 8, characterized in that: The robotic fish comprises a first tail fin unit and a second tail fin unit uniformly distributed along a circumferential direction, a first roll angle adjustment mechanism connected to the first tail fin unit, and a second roll angle adjustment mechanism connected to the second tail fin unit. The control method comprises: adjusting the first roll angle adjustment mechanism and / or the second roll angle adjustment mechanism to move axially along the mounting hole (101) and then rotating the mechanism to deflect the roll angle of the first tail fin unit and / or the second tail fin unit.

10. The control method of a robotic fish with independently adjustable tail fin roll angle according to claim 9, characterized in that: Also includes: By changing the initial connection position of the crank-connecting rod mechanism formed by the roll angle adjustment mechanism (2) and the first section (301), or / and changing the initial connection position of the crank-connecting rod mechanism formed by the roll angle adjustment mechanism (2) and the tail section (302), the angle between the first section (301) and the roll angle adjustment mechanism (2) and the angle between the tail section (302) and the roll angle adjustment mechanism (2) are adjusted, thereby adjusting the motion phase difference between the first section (301) and the tail section (302), thereby changing the wavelength of the fitted sinusoidal wave swing motion.

Images