A multi-joint bionic fish with a single drive assembly and method

Abstract

The present invention discloses a multi-joint bionic fish with a single drive assembly and a method thereof. The bionic fish comprises a bionic fish body and a tail-swinging mechanism connected thereto. The tail-swinging mechanism comprises: a drive assembly connected to the bionic fish body; a transmission rod for receiving power from the drive assembly to achieve swinging of both ends of the transmission rod; a first joint assembly, wherein the head ends of the two side rods of the assembly are symmetrically hinged to the two ends of the transmission rod, the two ends of the first support rod are respectively hinged to the two side rods, and the head end of the first center rod is fixed to the first support rod; a second joint assembly comprises: a parallelogram frame formed by hinged connection of the second support rod, a third side rod, a third support rod and a fourth side rod, the frame being hinged to the first joint assembly; and a tail fin joint assembly being hinged to the second joint assembly. Through the motion coupling of the joints, an efficient and stable reciprocating swinging motion of the fish tail is achieved, overcoming the problems of uneven force on the rods of the traditional connecting rod structure and the inability to flexibly adjust the swing amplitude and speed.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater robots, in particular to a multi-joint bionic fish with a single drive component and a method thereof. Background Art

[0002] Underwater robots using traditional propellers generate lateral vortices during propulsion, increasing energy consumption, reducing propulsion efficiency, and generating significant noise. Fish in the ocean have evolved over millions of years to develop remarkable swimming abilities. They generate propulsion by pushing the surrounding water through body movement. Precise control of vortices enables efficient and maneuverable swimming. Researchers have been striving to mimic the propulsion patterns of fish and develop efficient, low-noise, and flexible bionic fish for operations in complex underwater environments.

[0003] Existing bionic fishtail drive technology mainly adopts multi-servo series drive design and simple connecting rod transmission design. However, these traditional solutions have significant technical limitations: the multi-servo solution requires the configuration of multiple independent drive units, which increases the complexity of the system and makes it difficult to control the joint synchronization; the traditional connecting rod design has disadvantages such as too many servos, asymmetric left and right swing of the tail, complex structure, small swing torque, few swingable joints, fixed swing mode, and poor swing continuity. Summary of the Invention

[0004] The object of the present invention is to provide a multi-joint bionic fish with a single drive assembly and a method to solve the problems raised in the above-mentioned background technology and realize symmetrical, stable and controllable swinging of the multi-joint tail-swinging mechanism.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A multi-joint bionic fish with a single drive assembly, comprising a bionic fish body and a tail swinging mechanism connected thereto, wherein the tail swinging mechanism comprises: a housing, a drive assembly, a transmission rod, a first joint assembly, a second joint assembly and a tail fin joint assembly connected in sequence;

[0007] The driving assembly is connected to the bionic fish body and is used to output power;

[0008] The transmission rod is used to receive power from the driving assembly to allow the transmission rod to swing;

[0009] The first joint assembly includes: a first support rod, a first center rod, a first side rod, and a second side rod; the first ends of the first side rod and the second side rod are symmetrically hinged to the two ends of the transmission rod, the two ends of the first support rod are respectively hinged to the first side rod and the second side rod, and the first end of the first center rod is fixed to the first support rod;

[0010] The second joint assembly includes: a parallelogram frame formed by hingedly connecting the second support rod, the third side rod, the third support rod and the fourth side rod in sequence end to end; the head ends of the third side rod and the fourth side rod are hingedly connected to the tail ends of the first side rod and the second side rod respectively; the second support rod passes through a through hole corresponding to the tail end of the first center rod, so as to allow the first center rod to slide in the through hole, so that the second joint assembly can swing along with the first joint assembly;

[0011] The tail fin joint assembly is hinged to the second joint assembly so that the tail fin joint assembly can swing along with the second joint assembly;

[0012] The shell is used to wrap the first joint assembly, the second joint assembly and the tail fin joint assembly.

[0013] Furthermore, the second joint assembly further comprises: an expansion joint assembly;

[0014] The expansion joint assembly includes: a first expansion side rod, a second expansion side rod, an expansion support rod and an expansion center rod; the tail ends of the first expansion side rod and the second expansion side rod are hinged on the expansion support rod to form a C-shaped frame, and the head ends of the first expansion side rod and the second expansion side rod are hinged to the two ends of the third support rod; the expansion support is fixed on the second support rod, and the head end, middle part and tail end of the expansion center rod are each provided with a through hole, which are respectively movably connected to the expansion support, the third support rod and the expansion support rod.

[0015] Furthermore, a groove is provided on the side of the expansion support that contacts the through hole on the second support rod to prevent it from blocking the sliding of the first center rod.

[0016] Furthermore, the tail fin joint assembly includes: a tail fin support, a tail fin center rod and a tail fin; the tail fin support is fixed on the third support rod, and the head end, middle part and tail end of the tail fin center rod are each opened with a through hole, which is movably connected to the tail fin support and the expansion support rod in turn, and fixedly connected to the tail fin.

[0017] Furthermore, the tail fin joint assembly includes: a tail fin support, a tail fin center rod and a tail fin; the tail fin support is fixed on the second support rod, and a groove is provided at the position where the tail fin support contacts the through hole of the second support rod, and the head end, middle part and tail end of the tail fin center rod each have a through hole, which are movably connected to the tail fin support and the third support rod in turn, and fixedly connected to the tail fin.

[0018] Furthermore, the drive assembly includes: a mounting seat, a servo, a driving gear and a driven gear; the mounting seat is fixedly connected to the bionic fish body, the servo is fixed on the mounting seat, the driving gear is fixed to the output end of the servo, the driven gear is fixed on the transmission rod and meshes with the driving gear, and the middle part of the transmission rod is hinged to the mounting seat.

[0019] Furthermore, the second joint assembly further comprises: a first hinge seat, a second hinge seat, a third hinge seat and a second center rod;

[0020] The first hinge seat, the second hinge seat and the third hinge seat are in the shape of a cylindrical boss, and a threaded hole is opened in the center of the boss, and a screw is screwed in to prevent the component mounted on the cylindrical boss from falling out; the first hinge seat is fixedly connected to the upper end face of the second support rod, and the second hinge seat and the third hinge seat are fixedly connected to the upper end face and the lower end face of the third support rod respectively, and the openings at both ends of the second center rod are respectively nested with the cylindrical bosses of the first hinge seat and the second hinge seat to achieve hinged connection; the hole of the tail fin center rod for connecting with the third support rod is a waist-shaped hole, and the cylindrical boss of the third hinge seat is embedded in the waist-shaped hole, and the side surface of the cylindrical boss is attached to the wall of the waist-shaped hole on the tail fin center rod to achieve linkage.

[0021] Furthermore, the shell is used to wrap the first joint assembly, the second joint assembly, and the tail fin joint assembly. Specifically:

[0022] The housing includes a first housing component, a second housing component and a third housing component;

[0023] The first housing assembly includes: a first housing and a first housing connecting seat;

[0024] Wherein, both ends of the first shell connecting base are fixedly connected to the first shell and the first center rod respectively;

[0025] The second housing assembly includes: a second housing and a second housing connecting seat;

[0026] Wherein, the two ends of the second shell connecting base are respectively fixedly connected to the second shell and the second center rod;

[0027] The third housing assembly includes: a third housing and a third housing connecting seat;

[0028] Wherein, both ends of the third shell connecting seat are fixedly connected to the third shell and the tail fin center rod respectively.

[0029] A method for using a multi-jointed bionic fish with a single drive assembly, based on any one of the multi-jointed bionic fish with a single drive assembly, comprising:

[0030] The driving component drives the transmission rod to swing, and the transmission rod drives the first joint component to swing, and at the same time drives the first shell component fixed on the first joint component to swing synchronously. After the first joint component is driven, it transmits the transmission to the second joint component connected thereto, thereby causing the second joint component to swing and synchronously drive the second shell component fixed on the second joint component to swing synchronously. After the second joint component is driven, it transmits the transmission to the tail fin joint component connected thereto, thereby causing the tail fin joint component to swing and synchronously drive the third shell component fixed on the tail fin joint component to swing synchronously.

[0031] Furthermore, the swinging process of the first joint component is:

[0032] When the servo rotates from the initial position to a set angle in any direction, the driving gear rotates synchronously by the same angle, driving the driven gear to rotate a certain angle θ1, and then the transmission rod rotates by the same angle θ1; the first side rod and the second side rod are driven by the transmission rod to move, and the transmission rod and the first support rod are parallel to each other when moving, so the first support rod rotates by angle θ1, and then the first center rod rotates synchronously by angle θ1; the first side rod and the second side rod are parallel to each other when moving, so the first side rod and the second side rod move in opposite directions.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The present invention adopts a single drive component, i.e., a single servo drive, and realizes the synchronous relative swing of multiple joints based on kinematic coupling. By controlling the rotation state of the servo, the swing amplitude and speed of the tail joint can be adjusted, thereby improving the transmission efficiency and being more in line with the biomechanical characteristics of the fish propulsion mode.

[0035] (2) The present invention adopts a symmetrical transmission connecting rod mechanism, which ensures the symmetry of left and right swing through the geometric constraints of the connecting rod, significantly reduces the heading deviation caused by the deflection of the propulsion force vector, and effectively improves the motion trajectory distortion problem caused by asymmetric swing.

[0036] (3) The present invention adopts a transmission design of two side rods combined with a central rod, which can transmit the torque transmitted by the driving mechanism to each rod more evenly, reduce the strength loss of the rod, and increase the service life of the mechanism.

[0037] (4) The present invention can realize the installation of several joints and has good expandability. The expansion of more joints can make the swing curve simulated by the tail swing mechanism smoother and more in line with the movement characteristics of the fish propulsion mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1This is a schematic structural diagram of the joint components of a tail swing mechanism according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the overall structure of a tail swing mechanism according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic structural diagram of a drive assembly of a tail swing mechanism according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic structural diagram of a first joint assembly of a tail swing mechanism according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic structural diagram of the second joint assembly of the tail swing mechanism according to an embodiment of the present invention;

[0043] Figure 6 This is a schematic structural diagram of a tail fin joint assembly of a tail swing mechanism according to an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the connection between all housing components and joint components of a tail swing mechanism according to an embodiment of the present invention;

[0045] Figure 8 This is a structural diagram of the mounting base parts of the tail swing mechanism according to an embodiment of the present invention;

[0046] Figure 9 This is a structural diagram of the transmission rod parts of the tail swing mechanism according to an embodiment of the present invention;

[0047] Figure 10 This is a structural diagram of the second support rod component of the tail swing mechanism according to an embodiment of the present invention;

[0048] Figure 11 This is a schematic structural diagram of the first hinge seat, the second hinge seat, and the third hinge seat of the tail swing mechanism according to an embodiment of the present invention;

[0049] Figure 12 This is a schematic diagram of the joint structure of the tail swing mechanism swinging to one side according to an embodiment of the present invention;

[0050] Figure 13 This is a schematic diagram of the overall structure of a tail swing mechanism swinging to one side according to an embodiment of the present invention;

[0051] Figure 14 This is a schematic diagram of the joint structures of the tail swing mechanism swinging to the opposite side according to an embodiment of the present invention;

[0052] Figure 15 This is a schematic diagram of the overall structure of a tail swing mechanism that swings to the opposite side according to an embodiment of the present invention.

[0053] Figure 16 A top view of a tail swing mechanism including an expansion joint assembly according to an embodiment of the present invention;

[0054] Figure 17 This is a front view of a tail swing mechanism including an expansion joint assembly according to an embodiment of the present invention;

[0055] Figure 18 A bottom view of a tail swing mechanism including an expansion joint assembly according to an embodiment of the present invention;

[0056] Among them, 10, drive assembly; 11, mounting seat; 111, mounting hole; 112, square groove; 12, servo; 13, drive gear; 14, driven gear; 15, transmission rod; 151, sink; 20, first joint assembly; 21, first support rod; 22, first center rod; 23, first side rod; 24, second side rod; 30, second joint assembly; 31, second support rod; 311, through hole; 32, second center rod; 33, third side rod; 34, third support rod; 35, second hinge seat; 36, third hinge seat; 37, fourth side rod; 38, first hinge seat; 40, tail fin joint assembly; 41, Tail fin support; 411, semicircular groove; 42, gasket; 43, tail fin center rod; 431, waist-shaped hole; 44, tail fin; 50, first shell assembly; 51, first outer shell; 52, first outer shell connecting seat; 60, second shell assembly; 61, second outer shell; 62, second outer shell connecting seat; 70, third shell assembly; 71, third outer shell; 72, third outer shell connecting seat; 80, expansion joint assembly; 81, first expansion side rod; 82, second expansion side rod; 83, expansion support rod; 84, expansion center rod; 85, expansion support; 86, first expansion hinge seat; 87, second expansion hinge seat; 88, outer shell mounting rod. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and do not limit the present invention.

[0058] In the description of the application, it should be understood that the directions or positional relationships indicated by terms such as "up", "down", "front", "back", "left", "right", "clockwise", and "counterclockwise" are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0060] A multi-joint bionic fish with a single drive assembly, comprising a bionic fish body and a tail swinging mechanism connected thereto, wherein the tail swinging mechanism comprises: a housing, a drive assembly 10, a transmission rod 15, a first joint assembly 20, a second joint assembly 30 and a tail fin joint assembly 40 connected in sequence;

[0061] The driving assembly 10 is connected to the bionic fish body and is used to output power;

[0062] The transmission rod 15 is used to receive power from the driving assembly 10 to achieve the swing of both ends of the transmission rod 15;

[0063] The first joint assembly 20 includes: a first support rod 21, a first center rod 22, a first side rod 23, and a second side rod 24; the first ends of the first side rod 23 and the second side rod 24 are symmetrically hinged to the two ends of the transmission rod 15, the two ends of the first support rod 21 are hinged to the first side rod 23 and the second side rod 24 respectively, and the first end of the first center rod 22 is fixed to the first support rod 21;

[0064] The second joint assembly 30 includes: a parallelogram frame formed by hingedly connecting a second support rod 31, a third side rod 33, a third support rod 34 and a fourth side rod 37 in sequence. The head ends of the third side rod 33 and the fourth side rod 37 are hingedly connected to the tail ends of the first side rod 23 and the second side rod 24 respectively. The second support rod 31 passes through a through hole 311 corresponding to the tail end of the first center rod 22, so as to allow the first center rod 22 to slide in the through hole 311, thereby realizing the follow-up movement of the first joint assembly 20 and the second joint assembly 30.

[0065] The tail fin joint assembly 40 is hinged to the second joint assembly 30 to achieve follow-up movement of the second joint assembly 30 and the tail fin joint assembly 40 .

[0066] The shell is used to enclose the first joint assembly 20, the second joint assembly 30 and the tail fin joint assembly 40. Example 1:

[0067] See Figure 1 and Figure 2 The embodiment of the present invention provides a multi-joint bionic fish with a single drive assembly, comprising: a bionic fish body, a drive assembly 10, a first joint assembly 20, a second joint assembly 30, a tail fin joint assembly 40, a first housing assembly 50, a second housing assembly 60, and a third housing assembly 70;

[0068] The bionic fish body adopts the existing bionic fish body structure;

[0069] The output end of the driving assembly 10 is connected to the input end of the first joint assembly 20, the output end of the first joint assembly 20 is connected to the input end of the second joint assembly 30, and the output end of the second joint assembly 30 is connected to the input end of the tail fin joint assembly 40;

[0070] The first housing assembly 50 is fixedly connected to the first joint assembly 20 , the second housing assembly 60 is fixedly connected to the second joint assembly 30 , and the third housing assembly 70 is fixedly connected to the third joint assembly 40 .

[0071] The driving component 10 drives the first joint component 20 to swing and simultaneously drives the first shell component 50 fixed on the first joint component 20 to swing synchronously. After the first joint component 20 is driven, it transmits the signal to the second joint component 30 connected thereto, thereby causing the second joint component 30 to swing and synchronously drive the second shell component 60 fixed on the second joint component 30 to swing synchronously. After the second joint component 30 is driven, it transmits the signal to the third joint component 40 connected thereto, thereby causing the third joint component 40 to swing and synchronously drive the third shell component 70 fixed on the third joint component 40 to swing synchronously, thereby realizing the synchronous and different amplitude swinging of the three joint components, thereby simulating the swinging posture of the fish tail for driving.

[0072] The following is combined with Figures 1 to 15 , the embodiments of the present invention are described in detail through specific examples.

[0073] See Figure 3 The drive assembly 10 includes: a mounting base 11, a servo 12, a driving gear 13, a driven gear 14 and a transmission rod 15; the servo 12 is fixedly connected to the driving gear 13 and fixedly connected to the mounting base 11, the driven gear 14 is meshed with the driving gear 13 and fixedly connected to the transmission rod 15, and the transmission rod 15 and the driven gear 14 are hinged to the mounting base 11; wherein, the mounting base 11 is provided with a plurality of mounting holes 111 for connecting to the bionic fish body or other machine carrier and a square groove 112 for placing the servo 12, and the middle part of the transmission rod 15 is provided with an incomplete circular sink 151 for placing the driven gear 14.

[0074] In this embodiment, the servo will rotate back and forth at a certain angle according to the control signal to achieve the periodic swing of the tail structure. Figure 1The position of the center rods when they are parallel is shown in the figure. When the center rods are parallel to each other, the driving gear 13 fixedly connected to the servo 12 rotates clockwise by a set angle. The driving gear 13 fixedly connected to the servo 12 rotates synchronously by the same angle, thereby driving the driven gear 14 meshing therewith to rotate by a certain angle (the angle is determined by the transmission ratio between the two gears). Assume that the angle is θ1. This in turn drives the transmission rod 15 fixedly connected to the driven gear 14 to rotate by the same angle θ1.

[0075] See Figure 4 、 Figure 12 The first joint assembly 20 includes: a first support rod 21, a first center rod 22, a first side rod 23 and a second side rod 24; the ends of the first side rod 23 and the second side rod 24 close to the driving assembly 10 are respectively hinged to the two ends of the transmission rod 15, and the middle parts of the first side rod 23 and the second side rod 24 are respectively hinged to the two ends of the first support rod 21, the middle part of the first support rod 21 is hinged to the mounting seat 11, and the first center rod 22 is fixedly connected to the first support rod 21; wherein, the first side rod 23, the second side rod 24 away from the end of the driving assembly 10 and the two ends of the first support rod 21 are provided with slots.

[0076] When the transmission rod 15 is driven to rotate an angle of θ1, the first side rod 23 and the second side rod 24 hinged at both ends of the transmission rod 15 are driven to move. Since the middle parts of the first side rod 23 and the second side rod 24 are hinged to the two ends of the first support rod 21 respectively, a parallelogram linkage mechanism is formed between the first side rod 23, the second side rod 24, the transmission rod 15 and the first support rod 21. Therefore, when the transmission rod 15 and the first support rod 21 move, they are parallel to each other, that is, the first support rod 21 also rotates by an angle of θ1, and then the first center rod 22 fixedly connected to the first support rod 21 also rotates synchronously by an angle of θ1; at the same time, when the first side rod 23 and the second side rod 24 move, they are also parallel to each other, that is, the first side rod 23 pushes forward and the second side rod 24 pulls backward.

[0077] Thus, through the above embodiment, the rotation of the first center rod 22 in the first joint assembly 20 by the angle θ1 is achieved.

[0078] See Figure 5 、 Figure 12The second joint assembly 30 includes: a second support rod 31, a third support rod 34, a second center rod 32, a third side rod 33, a fourth side rod 37, a first hinge seat 38, a second hinge seat 35 and a third hinge seat 36; wherein, the second support rod 31 and the third support rod 34 have slots at both ends, and the middle of the second support rod 31 is provided with a square through hole 311 that completely passes through; the third side rod 33 and the fourth side rod 37 are respectively hinged to the first side rod 23 and the second side rod 24 at one end close to the first joint assembly 20, and the middle of the third side rod 33 and the fourth side rod 37 are respectively hinged to the two ends of the second support rod 31 The ends are hinged, the through hole 311 in the middle of the second support rod 31 is movably connected to the first center rod 22 and the two side edges of the first center rod 22 are attached to the two side edges of the through hole 311 to achieve linkage; the first hinge seat 38 is fixedly connected to the second support rod 31, the second hinge seat 35 and the third hinge seat 36 are respectively fixedly connected to the upper and lower surfaces of the third support rod 34, and the two ends of the second center rod 32 are respectively hinged to the first hinge seat 38 and the second hinge seat 35; wherein, the first hinge seat 38, the second hinge seat 35 and the third hinge seat 36 are all provided with a cylindrical boss, and a threaded hole is opened in the center of the boss for screwing in a screw.

[0079] When the first center rod 22 is driven to rotate by an angle θ1, the second support rod 31 movably connected to the first center rod 22 through the through hole 311 will be linked by the force applied to the through hole 311 when the first center rod 22 slides, and will also rotate by an angle θ1 with the rotation center of the first support rod 21 as the center of the circle, thereby driving the third side rod 33 and the fourth side rod 37 hinged on the second support rod 31 to move toward the side where the first support rod 21 rotates; at the same time, since the third side rod 33 and the fourth side rod 37 are hinged to one end of the first side rod 23 and the second side rod 24, they will be restricted by the hinge point and rotated, and the two motions are finally coupled. The third side rod 33 and the fourth side rod 37 are rotated at an angle θ2; a parallelogram linkage mechanism is formed between the third side rod 33, the fourth side rod 37, the second support rod 31 and the third support rod 34, so that the third support rod 34 is parallel to the second support rod 31 when moving, and moves toward the rotation side with the third side rod 33 and the fourth side rod 37; and the two ends of the second center rod 32 are respectively hinged to the first hinge seat 38 and the second hinge seat 35, that is, the second center rod 32 is the center line of the parallelogram linkage mechanism, and its movement is also parallel to the third side rod 33 and the fourth side rod 37, that is, it also rotates at an angle θ2.

[0080] Thus, through the above embodiment, the rotation of the second center rod 32 in the second joint assembly 30 by the angle θ2 is achieved.

[0081] See Figure 6 、 Figure 12 The tail fin joint assembly 40 includes: a tail fin center rod 43, a tail fin support 41, a washer 42, and a tail fin 44; wherein, a waist-shaped hole 431 is opened in the middle of the tail fin center rod 43, and a semicircular groove 411 is opened at one end of the tail fin support 41 close to the second support rod 31 to provide movement space for the first center rod 22; one end of the tail fin support 41 is fixedly connected to the second support rod 31, and the other end is hinged to one end of the tail fin center rod 43, and the washer 42 is placed between the second support rod 31 and the tail fin center rod 43 to compensate for the assembly gap, and the waist-shaped hole 431 in the middle of the tail fin center rod 43 is movably connected to the third hinge seat 36, and the side surface of the cylindrical boss of the third hinge seat 36 is attached to the surface of the waist-shaped hole 431 to realize linkage; the tail fin center rod 43 is fixedly connected to the tail fin 44 at one end away from the tail fin support 41.

[0082] Since one end of the tail fin support 41 is fixedly connected to the second support rod 31, the tail fin support 41 also rotates around the angle θ1 following the second support rod 31; the waist-shaped hole 431 of the tail fin center rod is movably connected to the third hinge seat 36, and the third hinge seat 36 is fixedly connected to the third support rod 34, that is, the third hinge seat 36 moves with the third support rod 34, thereby driving the tail fin center rod 43 movably connected to the third hinge seat 36 to move, and at the same time, one end of the tail fin center rod 43 is hinged to the tail fin support 41, and is limited by the hinge point to realize the rotation angle θ3 of the tail fin center rod 43, and at the same time drives the tail fin 44 fixed to the tail fin center rod 43 to also rotate around the angle θ3.

[0083] Thus, through the above embodiment, the rotation of the tail fin center rod 43 and the tail fin 44 in the third joint assembly 40 by the angle θ3 is achieved.

[0084] See Figure 7 、 Figure 13 , Figure 7 In order to conveniently show the connection relationship of each part, the first shell 51, the second shell 61 and the third shell 71 are shown as transparent in this figure. The first shell assembly 50 includes: a first shell 51, a first shell connecting seat 52;

[0085] In which, the two ends of the first shell connecting seat 52 are respectively fixedly connected to the first shell 51 and the first center rod 22; the second shell assembly 60 includes: a second shell 61, a second shell connecting seat 62; wherein, the two ends of the second shell connecting seat 62 are respectively fixedly connected to the second shell 61 and the second center rod 32; the third shell assembly 70 includes: a third shell 71, a third shell connecting seat 72; wherein, the two ends of the third shell connecting seat 72 are respectively fixedly connected to the third shell 71 and the tail fin center rod 43.

[0086] Since the first shell 51, the second shell 61 and the third shell 71 are respectively fixedly connected to the first center rod 22, the second center rod 32 and the tail fin center rod 43, the first shell 51 synchronously rotates by an angle θ1 following the first center rod 22, the second shell 61 synchronously rotates by an angle θ2 following the second center rod 32, and the first shell 51 synchronously rotates by an angle θ3 following the first center rod 22, thereby realizing the bionic appearance and motion of the tail swing mechanism.

[0087] Thus, through all the above-mentioned implementations, the rotation angles of the three joints are gradually increased to swing at three angles of θ1, θ2, and θ3.

[0088] On the basis of the above embodiment, a control signal is sent to make the steering gear 12 change the rotation direction (i.e., rotate counterclockwise), and the movement direction of each component is opposite to that of the above embodiment until it returns to the initial position. Figure 1 、 Figure 2 Continue to rotate the servo 12 counterclockwise, then the movement direction of each component is symmetrical with the movement direction of the above embodiment, the rotation angle of the three joints gradually increases to three angles α1, α2, and α3, and the rotation angle of the servo 12 is controlled so that α1, α2, and α3 are equal to θ1, θ2, and θ3 respectively, thereby achieving a symmetrical swing of the tail swing mechanism to the other side, as shown. Figure 14 、 Figure 15 At this time, a control signal is sent to make the servo 12 change the direction of rotation (ie, clockwise rotation), and the joint will return to the initial position as shown Figure 1 、 Figure 2 In the position shown, the control signal is adjusted to make the servo 12 rotate back and forth at a certain angle periodically, thereby realizing the periodic symmetrical swing of the tail-swinging structure. Then, by controlling the rotation state of the servo 12, the swing amplitude and speed of the tail joint can be adjusted to improve the transmission efficiency. The movement of the tail-swinging mechanism is more in line with the biomechanical characteristics of the fish propulsion mode.

[0089] Example 2:

[0090] This embodiment adds an expansion joint assembly based on the embodiment 1; the expansion joint assembly includes: an expansion joint assembly 80; a first expansion side rod 81; a second expansion side rod 82; an expansion support rod 83; an expansion center rod 84; an expansion support 85; a first expansion hinge seat 86; a second expansion hinge seat 87; and a housing mounting rod 88;

[0091] The tail ends of the first expansion side rod 81 and the second expansion side rod 82 are hinged on the expansion support rod 83 to form a C-shaped frame. The upper end face and the lower end face of the expansion support rod 83 are respectively fixed with the first expansion hinge seat 86 and the second expansion hinge seat 87. The two ends of the shell mounting rod 88 are hinged on the second hinge seat 35 and the first expansion hinge seat 86. The head ends of the first expansion side rod 81 and the second expansion side rod 82 are hinged to the two ends of the third support rod 34; the expansion support 85 is fixed on the second support rod 31, and the head end of the expansion center rod 84 has a through hole, and the middle and tail ends have a through hole. A waist-shaped hole is movably connected to the expansion support 85, the third hinge seat 36 of the third support rod 34 and the second expansion hinge seat 87 of the expansion support rod 83; correspondingly, one end of the tail fin support 41 is fixedly connected to the third support rod 34, and the other end is hinged to one end of the tail fin center rod 43. The waist-shaped hole 431 in the middle of the tail fin center rod 43 is movably connected to the first expansion hinge seat 86, and the side surface of the cylindrical boss of the first expansion hinge seat 86 is attached to the surface of the waist-shaped hole 431 to realize linkage; the end of the tail fin center rod 43 away from the tail fin support 41 is fixedly connected to the tail fin 44.

[0092] Through this implementation, it can be seen that the present invention has good scalability and can realize the installation of multiple joints;

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-joint bionic fish with a single drive assembly, comprising a bionic fish body and a tail swinging mechanism connected thereto, characterized in that: The tail swing mechanism comprises: a housing, a driving assembly, a transmission rod, a first joint assembly, a second joint assembly and a tail fin joint assembly connected in sequence; The driving assembly is connected to the bionic fish body and is used to output power; The transmission rod is used to receive power from the driving assembly to allow the transmission rod to swing; The first joint assembly includes: a first support rod, a first center rod, a first side rod, and a second side rod; the first ends of the first side rod and the second side rod are symmetrically hinged to the two ends of the transmission rod, the two ends of the first support rod are respectively hinged to the first side rod and the second side rod, and the first end of the first center rod is fixed to the first support rod; The second joint assembly includes: a parallelogram frame formed by hingedly connecting the second support rod, the third side rod, the third support rod, and the fourth side rod end to end in sequence, wherein the head ends of the third side rod and the fourth side rod are hingedly connected to the tail ends of the first side rod and the second side rod respectively, and the second support rod passes through a through hole corresponding to the tail end of the first center rod, so as to allow the first center rod to slide in the through hole; The tail fin joint assembly is hinged to the second joint assembly; The shell is used to wrap the first joint assembly, the second joint assembly and the tail fin joint assembly.

2. The multi-jointed bionic fish with a single drive assembly according to claim 1, characterized in that: The second joint assembly further comprises: an expansion joint assembly; the expansion joint assembly comprises: a first expansion side rod, a second expansion side rod, an expansion support rod and an expansion center rod; The tail ends of the first expansion side rod and the second expansion side rod are hinged on the expansion support rod to form a C-shaped frame, and the head ends of the first expansion side rod and the second expansion side rod are hinged to the two ends of the third support rod; the expansion support is fixed on the second support rod, and the head end, middle part and tail end of the expansion center rod are each provided with a through hole, which are respectively movably connected to the expansion support, the third support rod and the expansion support rod.

3. The multi-jointed bionic fish with a single drive assembly according to claim 2, characterized in that: A groove is formed on the side of the expansion support that contacts the through hole on the second support rod to prevent it from blocking the sliding of the first center rod.

4. The multi-jointed bionic fish with a single drive assembly according to claim 2, characterized in that: The tail fin joint assembly includes: a tail fin support, a tail fin center rod and a tail fin; the tail fin support is fixed on the third support rod, and the head end, middle part and tail end of the tail fin center rod are each opened with a through hole, which is movably connected to the tail fin support and the expansion support rod in turn, and fixedly connected to the tail fin.

5. The multi-jointed bionic fish with a single drive assembly according to claim 1, characterized in that: The driving assembly includes: a mounting seat, a servo, a driving gear and a driven gear; the mounting seat is fixedly connected to the bionic fish body, the servo is fixed on the mounting seat, the driving gear is fixed to the output end of the servo, the driven gear is fixed on the transmission rod and meshes with the driving gear, and the middle part of the transmission rod is hinged to the mounting seat.

6. The multi-jointed bionic fish with a single drive assembly according to claim 1, characterized in that: The tail fin joint assembly includes: a tail fin support, a tail fin center rod and a tail fin; the tail fin support is fixed on the second support rod, and a groove is provided at the position where the tail fin support contacts the through hole of the second support rod. The head end, middle part and tail end of the tail fin center rod each have a through hole, which are movably connected to the tail fin support and the third support rod in turn, and fixedly connected to the tail fin.

7. The multi-jointed bionic fish with a single drive assembly according to claim 6, characterized in that: The second joint assembly further comprises: a first articulated seat, a second articulated seat, a third articulated seat and a second center rod; The first hinge seat, the second hinge seat and the third hinge seat are in the shape of a cylindrical boss, and a threaded hole is opened in the center of the boss, and a screw is screwed in to prevent the component mounted on the cylindrical boss from falling out; the first hinge seat is fixedly connected to the upper end face of the second support rod, and the second hinge seat and the third hinge seat are fixedly connected to the upper end face and the lower end face of the third support rod respectively, and the openings at both ends of the second center rod are respectively nested with the cylindrical bosses of the first hinge seat and the second hinge seat to achieve hinged connection; the hole of the tail fin center rod for connecting with the third support rod is a waist-shaped hole, and the cylindrical boss of the third hinge seat is embedded in the waist-shaped hole, and the side surface of the cylindrical boss is attached to the wall of the waist-shaped hole on the tail fin center rod to achieve linkage.

8. The multi-jointed bionic fish with a single drive assembly according to claim 7, characterized in that: The shell is used to wrap the first joint assembly, the second joint assembly, and the tail fin joint assembly. Specifically: The housing includes a first housing component, a second housing component and a third housing component; The first housing assembly includes: a first housing and a first housing connecting seat; Wherein, both ends of the first shell connecting base are fixedly connected to the first shell and the first center rod respectively; The second housing assembly includes: a second housing and a second housing connecting seat; Wherein, the two ends of the second shell connecting base are respectively fixedly connected to the second shell and the second center rod; The third housing assembly includes: a third housing and a third housing connecting seat; Wherein, both ends of the third shell connecting seat are fixedly connected to the third shell and the tail fin center rod respectively.

9. A method for using a multi-jointed bionic fish with a single drive assembly, based on the multi-jointed bionic fish with a single drive assembly according to any one of claims 1 to 8, characterized in that: include: The driving component drives the transmission rod to swing, and the transmission rod drives the first joint component to swing, and at the same time drives the first shell component fixed on the first joint component to swing synchronously. After the first joint component is driven, it transmits the transmission to the second joint component connected thereto, thereby causing the second joint component to swing and synchronously drive the second shell component fixed on the second joint component to swing synchronously. After the second joint component is driven, it transmits the transmission to the tail fin joint component connected thereto, thereby causing the tail fin joint component to swing and synchronously drive the third shell component fixed on the tail fin joint component to swing synchronously.

10. The method of use according to claim 9, characterized in that: The swing process of the first joint component is: When the servo rotates from the initial position to a set angle in any direction, the driving gear rotates synchronously by the same angle, driving the driven gear to rotate a certain angle θ1, and then the transmission rod rotates by the same angle θ1; the first side rod and the second side rod are driven by the transmission rod to move, and the transmission rod and the first support rod are parallel to each other when moving, so the first support rod rotates by angle θ1, and then the first center rod rotates synchronously by angle θ1; the first side rod and the second side rod are parallel to each other when moving, so the first side rod and the second side rod move in opposite directions.

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