Single-joint high-speed mechanical fish tail propelling mechanism and propelling method thereof

Abstract

The invention relates to a single-joint high-speed mechanical fish tail propelling mechanism and a propelling method thereof. The single-joint high-speed mechanical fish tail propelling mechanism comprises a shell, a supporting plate, a fish tail connecting piece and a tail fin which are sequentially arranged from front to back. The direct-current propulsion motor is fixed to the shell through an L-shaped fixing plate and connected with the rotating disc through a half coupling, and the rotating disc drives the connecting rod gear to reciprocate. The upper half portion of the front end of the fishtail connecting piece is connected with the driven gear, the lower half portion is connected to the shell through a supporting plate, and the rear end is connected with the tail fin. The motor drives the meshed driven gear to swing back and forth through the connecting rod gear, drives the tail fin to swing through the fishtail connecting piece, and pushes the mechanical fish to swim forwards. The direct-current motor is adopted to drive the transmission mechanism to achieve the design of the high-speed mechanical fishtail, high-frequency movement can be easily achieved, the smoothness of high-frequency swing and the reliability of long-time use are far better than those of a traditional steering engine driving mode, and performance improvement and wide application prospects are brought to the technical field of bionic fishes.

Description

Technical Field:

[0001] The present invention relates to a single-joint high-speed mechanical fish tail propulsion mechanism and a propulsion method thereof. Background Art:

[0002] The research on bionic robotic fish began in the 1990s. In the early stage, it mainly focused on theoretical modeling and exploration of propulsion mechanisms. With the progress of bionics, material science, and robotics technology, in recent years, the research has gradually developed towards high-performance drive, new mechanism design, and practical application.

[0003] The research team of Beihang University adopted a single-motor-driven compound link mechanism to make the tail fin swing and achieve the propulsion function. The research team of Harbin Institute of Technology adopted an eccentric wheel mechanism, where the output shaft of the motor is connected to an eccentric wheel. When the motor rotates, the eccentric wheel drives the link to move, making the tail fin swing. The research team of the School of Engineering of Ocean University of China has conducted in-depth research on the body / caudal fin propulsion mode (BCF) bionic robotic fish, and the main transmission scheme is direct drive by a servo motor. The Massachusetts Institute of Technology (MIT) uses a motor to directly drive the tail fin, and the output shaft of the motor is directly connected to the tail fin, and the rotation of the motor directly drives the tail fin to swing. The University of Cambridge uses electromagnetic drive for the tail fin, and the electromagnetic driver is directly connected to the tail fin. By changing the intensity and direction of the electromagnetic field, the swing of the tail fin is controlled. The team of Toshio Fukuda at Nagoya University in Japan developed an SMA-driven micro-undulating thruster and a piezoelectric ceramic-driven double-fin robotic fish, which are suitable for operation in narrow spaces.

[0004] Currently, there are many organizations researching robotic fish, and the drive methods are more diverse. In addition to servo drive, other schemes such as electromagnetic drive and cable drive have also been explored. When designing high-speed robotic fish using the above several methods, high-speed propulsion relies on the high-frequency swing of the mechanical tail fin, and a specially customized high-frequency servo motor is required, which not only increases the design and R & D costs, but also is not suitable for long-term use due to the disadvantages of small driving torque, easy damage, and slow response speed of the servo motor. Therefore, a new propulsion method driven by a DC motor to drive a gear transmission mechanism to drive the high-frequency swing of the tail fin is designed to replace the drive method of the high-frequency servo motor. Summary of the Invention:

[0005] The present invention makes improvements to the problems existing in the above-mentioned prior art. That is, the technical problem to be solved by the present invention is to provide a single-joint high-speed mechanical fish tail propulsion mechanism and a propulsion method thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a single-joint high-speed mechanical fish tail propulsion mechanism, comprising a housing, a support plate, a fish tail connecting piece and a tail fin arranged in sequence from front to back. The L-shaped fixing plate is connected to the fish body by screws. The DC propulsion motor is connected to the motor bracket, and the motor bracket is connected to the L-shaped fixing plate by bolts to fix the DC propulsion motor. The half coupling is locked to the outer extension shaft of the DC propulsion motor by a set screw, and the half coupling is connected to the turntable by screws. Therefore, the DC propulsion motor can drive the turntable to achieve fixed-axis rotation.

[0007] Further, the outer extension shaft at the upper end of the turntable is inserted into the link gear chute. The link gear is fixed to the support plate by screws. A rolling bearing is installed inside the link gear. The screw and the gear can rotate relative to each other through the bearing. Driving the turntable to rotate will drive the link gear to reciprocate left and right. The driven gear is connected to the upper half of the front end of the fish tail connecting piece by screws. The lower half of the front end of the fish tail connecting piece is connected to the support plate by bolts. The rear end of the fish tail connecting piece is connected to the tail fin. A linear ball bearing is installed inside the connection hole between the fish tail connecting piece and the support plate. The linear ball bearing is axially fixed by a bearing sleeve and bolts. The support plate and the fish tail connecting piece can rotate freely through the bearing. The link gear meshes with the driven gear. The motor drives the turntable to rotate, the turntable drives the link gear to swing left and right, and further drives the engaged driven gear to swing reciprocally. The swing of the driven gear drives the fish tail connecting piece and the tail fin to swing left and right together. The swing of the tail fin will push the mechanical fish to swim forward.

[0008] Compared with the prior art, the present invention has the following effects: The structure design of the present invention is simple and reasonable. Using a gear meshing high-speed transmission mechanism can enable the bionic fish to obtain better high-speed performance. The DC motor can obtain higher-frequency swings more easily through the mechanical transmission mechanism than directly driving the tail fin by a servo motor, avoiding the realization of high-frequency swings of the tail fin by developing a high-frequency servo motor. The DC motor drive is not only easy to obtain high-frequency swings, but also suitable for occasions of long-term use.

[0009] Compared with the prior art, the present invention has the following effects: in the current field of bionic fish technology, the traditional servo drive mode has been difficult to meet people's high requirements for the performance of bionic fish. The current solution is to develop high-frequency servos, which not only prolongs the design cycle but also increases the research and development cost. More importantly, the present invention adopts a DC motor to drive the tail fin through a mechanical transmission mechanism, which can not only easily achieve high-frequency movement, but also completely get rid of the dependence on high-frequency servos, which is of far-reaching significance for the performance improvement of bionic fish. In practical applications, the bionic fish driven by the DC motor shows excellent performance, whether it is the smoothness of high-frequency swinging or the reliability of long-term use, which far exceeds the traditional servo drive mode. It can be said that the DC motor of the present invention drives the bionic fish through gear meshing, which brings performance improvement and broad application prospects to the field of bionic fish technology, and will bring corresponding changes to the entire industry. Description of the drawings:

[0010] Figure 1 is a schematic diagram of the three-dimensional structure of an embodiment of the present invention;

[0011] Figure 2 is a schematic diagram of the main structure of an embodiment of the present invention;

[0012] Figure 3 is a front cross-sectional schematic diagram of an embodiment of the present invention with the fishtail removed;

[0013] Figure 4 is a schematic cross-sectional view of a motor transmission part of an embodiment of the present invention;

[0014] Figure 5 is a three-dimensional solid schematic diagram of the support plate;

[0015] Figure 6 It is a three-dimensional solid schematic diagram of the fishtail connector;

[0016] Figure 7 It is a three-dimensional solid schematic diagram of the motor bracket;

[0017] Figure 8 It is a three-dimensional solid schematic diagram of the half coupling.

[0018] In the figure:

[0019] 1-housing; 2-L-shaped fixing plate; 3-motor bracket; 4-DC propulsion motor; 5-turntable; 6-connecting rod gear; 7-support plate; 8-driven gear; 9-fishtail connector; 10-tail fin; 11-first screw; 12-second screw; 13-third screw; 14-bolt; 15-fourth screw; 16-half coupling; 17-fifth screw; 18-first bearing sleeve; 19-nut; 20-rolling bearing; 21-second bearing sleeve; 22-sixth screw; 23-setting screw; 24-seventh screw; 25-eighth screw; 26-linear ball bearing. Detailed implementation manner:

[0020] To more clearly explain the present invention, the present invention will be further described below in conjunction with the drawings and embodiments. Obviously, the following listed drawings are only some specific embodiments of the present invention.

[0021] As Figures 1 to 8 shown, a single-joint high-speed mechanical fish tail propulsion mechanism and its propulsion method of the present invention include a housing 1, a support plate 7, a fish tail connecting member 9, and a tail fin 10 arranged in sequence from front to back; the L-shaped fixing plate 2 is connected to the housing 1 by a first screw 11 to fix the L-shaped fixing plate 2; the motor bracket 3 is fixed to the L-shaped fixing plate 2 by an eighth screw 25, and the DC propulsion motor 4 is fixed to the motor bracket by a seventh screw 24, thereby fixing the DC propulsion motor to the housing; the half coupling 16 is fixed to the output shaft of the DC propulsion motor 4 by a set screw 23, and the sixth screw 22 connects the turntable 5 and the half coupling 16. After the DC propulsion motor 4 is powered on, the torque is transmitted to the turntable 5, so that the turntable 5 obtains a driving torque and realizes common rotation.

[0022] In this embodiment, the outer extension shaft on the upper surface of the turntable 5 is embedded in the chute of the connecting rod gear 6. The connecting rod gear 6 is connected to the support plate 7 by a fourth screw 15. A rolling bearing 20 is installed inside the connecting rod gear 6 to realize the relative rotation between the connecting rod gear 6 and the support plate 7. The lower surface of the inner ring of the bearing 20 is axially fixed by the outer convex shaft on the upper surface of the support plate 7. The upper surface of the inner ring of the rolling bearing 20 is in contact with the second bearing sleeve 21. The upper end of the second bearing sleeve 21 is fixed by a fourth screw 15, and the rolling bearing 20 is axially fixed by the bearing sleeve 21.

[0023] In this embodiment, the support plate 7 is connected to the fish tail connecting member 9 by a bolt 14. A linear ball bearing 26 is installed in the connection hole between the support plate 7 and the fish tail connecting body 9. First bearing sleeves 18 are respectively placed at both ends of the linear ball bearing 26. The linear ball bearing 26 and the first bearing sleeve 18 are integrally connected by a bolt 14 and tightened by a nut 19 to realize the axial fixation of the linear ball bearing 26. The linear ball bearing 26 realizes the free rotation between the support plate 7 and the fish tail connecting member 9.

[0024] In this embodiment, the fish tail connecting member 9 is connected to the tail fin 10 by a second screw 12. The movement of the fish tail connecting member will drive the tail fin to swing.

[0025] In this embodiment, the driven gear 8 is fixed to the fish tail connecting member 9 by a third screw 13; the DC propulsion motor 4 drives the turntable 5 to rotate through the half coupling 16, and then transmits the power to the connecting rod gear 6. The connecting rod gear 6 transmits the power to the driven gear by meshing with the driven gear 8, and then drives the fish tail connecting member 9 and the tail fin 10 to swing left and right. The swing of the tail fin provides the power for the fish body to move forward.

[0026] The above are only the preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A single-joint high-speed mechanical fish tail propulsion mechanism, characterized in that: It includes a housing, a support plate, a fish-tail connecting piece and a caudal fin which are arranged in sequence from front to back. The L-shaped fixing plate is connected to the fish body by screws. The DC propulsion motor is connected to the motor bracket, and the motor bracket is connected to the L-shaped fixing plate by bolts. Then the DC propulsion motor is fixed to the housing through the L-shaped fixing plate. The half coupling is locked to the outer extension shaft of the DC propulsion motor by a set screw, and the half coupling is connected to the turntable by screws.

2. The tail propulsion mechanism of a single-joint high-speed robotic fish according to claim 1, characterized in that: The outer extension shaft at the upper end of the turntable is embedded in the connecting rod gear chute. The connecting rod gear is fixed to the support plate by screws. A rolling bearing is installed inside the connecting rod gear, and the rolling bearing is positioned by a bearing sleeve and screws. The connecting rod gear can rotate freely with the support plate through the bearing. Driving the rotation of the outer extension shaft of the turntable will drive the connecting rod gear to reciprocate left and right. The upper half of the front end of the fish-tail connecting piece is connected to the driven gear, the lower half of the front end of the fish-tail connecting piece is connected to the support plate through bolts, and the rear end of the fish-tail connecting piece is connected to the caudal fin. A linear ball bearing is installed inside the connecting hole between the fish-tail connecting piece and the support plate, and the linear ball bearing is axially fixed by a bearing sleeve and bolts. The support plate and the fish-tail connecting piece can rotate freely through the bearing.

3. A working method of the tail propulsion mechanism of a single-joint robotic fish, characterized in that: It includes a single-joint high-speed mechanical fish tail propulsion mechanism as described in any one of claims 1 to 2. When working: the motor drives the turntable to rotate, the turntable drives the connecting rod gear to swing left and right, the connecting rod gear meshes with the driven gear, and then drives the engaged driven gear to swing reciprocally. The swing of the driven gear drives the fish-tail connecting piece and the caudal fin to swing left and right together, and the swing of the caudal fin will push the mechanical fish to swim forward.

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