Crocodile-like robot tail

Abstract

The present application relates to the technical field of bionic robot, and discloses a tail of a bionic crocodile robot, which comprises a driving device and a tail body. The driving device comprises a rope driving mechanism, and the tail body is installed on the driving device. The rope driving mechanism is connected to the two sides of the tail body respectively and is used to drive the tail body to swing. The tail body comprises a plurality of joints and a plurality of spring members. The plurality of joints are arranged on the same axis in sequence, and the plurality of spring members are connected and fixed between adjacent joints. Under the driving of the rope driving mechanism, the joints separated from each other in the tail body rotate through the plurality of spring members, so that the tail of the bionic crocodile robot is controlled to swing by a few driving motors. The problem that the tail of the bionic crocodile robot needs to be controlled to swing by multiple motors is solved completely.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of bionic robot technology, and particularly relates to a tail of a bionic crocodile robot. BACKGROUND

[0002] Amphibious robots have important roles in resource exploration and water-land rescue. The power source for the forward movement of amphibious robots such as crocodiles in water mainly relies on tail swing. Traditional bionic crocodile robots mostly adopt a "multi-segment rigid body type" tail design. This multi-segment rigid body tail design scheme needs to use multiple motors for driving. In the traditional multi-motor control mode, there is a problem of causing large friction loss. That is, the user needs to regularly maintain the bearings of each motor with lubricating oil. When the lubricating oil is added too little, the motor bearings will not run smoothly, and the friction loss will increase. When the lubricating oil is added too much, the friction torque will also increase, and the temperature will rise, causing the motor to fail. Therefore, under the premise of long-term use, the maintenance cost required by the traditional multi-motor structure is high. Moreover, since the multiple motors are distributed in the tail, the tail will be too heavy, thereby affecting the structural mass distribution. In the swing, the traditional bionic crocodile tail will cause the trunk to move laterally under the action of inertia, thereby reducing the stability of the overall swimming and affecting the swing simulation. In addition, the control of the traditional multi-motor is relatively complex, thereby reducing the control efficiency.

[0003] Therefore, it is of great significance to research a bionic crocodile robot tail that can use fewer driving motors to achieve more complex and agile tail curve control. SUMMARY

[0004] The present application aims to provide a bionic crocodile robot tail to solve the problem of the need for multi-motor control swing tail in the existing bionic crocodile robot tail.

[0005] To solve the above technical problems, the present application provides a bionic crocodile robot tail, which comprises a driving device and a tail body. The driving device comprises a rope driving mechanism. The tail body is installed on the driving device. The rope driving mechanism is respectively connected to the two sides of the tail body. The rope driving mechanism is used to drive the tail body to swing. The tail body comprises multiple joints and multiple groups of spring members. The multiple joints are sequentially arranged on the same axis. The multiple groups of spring members are connected and fixed between adjacent joints. The multiple groups of spring members are used to realize the rotational connection between adjacent joints.

[0006] In one of the embodiments, the spring member comprises a first spring, a second spring and a third spring; the joint comprises an arc plate, an axial rod and a radial rod; the first spring is fixedly connected to both sides of the arc plate; the axial rod is fixedly connected to the outer arc surface of the arc plate, and the second spring is fixedly connected to both sides of the axial rod; the radial rod is fixedly connected to the two sides of the arc plate, and the two radial rods are arranged on the same axis, and the third spring is fixedly connected to the end of the adjacent radial rod.

[0007] In one of the embodiments, the elastic coefficient of the second spring is greater than the elastic coefficient of the first spring and the elastic coefficient of the third spring.

[0008] In one of the embodiments, the ratio of the elastic coefficient of the first spring, the elastic coefficient of the second spring and the elastic coefficient of the third spring is 0.3:2:1 to 0.8:4:1.

[0009] In one of the embodiments, the axial rod and the radial rod are arranged perpendicularly.

[0010] In one of the embodiments, the outer arc surface of the arc plate is further fixedly connected with a convex body, and the convex body gradually widens away from the driving device.

[0011] In one of the embodiments, a through hole is arranged on the outer arc surface of the convex body, and the axial rod is fixedly connected to the through hole.

[0012] In one of the embodiments, the driving device further comprises a shell, and a bushing is arranged on the side wall of the shell, and the bushing is fixedly connected to the convex body adjacent to the driving device.

[0013] In one of the embodiments, the rope driving mechanism comprises a motor, a rocker and a driving rope; the motor and the rocker are fixedly connected to the shell, the motor is in transmission connection with the rocker, the ends of the rocker are respectively fixedly connected to the driving rope, and the driving rope is fixedly connected to the ends of the arc plate.

[0014] The beneficial effects of the present application are as follows:

[0015] Since the plurality of joints are sequentially arranged on the same axis, and a plurality of spring members are fixedly connected between the adjacent joints, when the joints are applied, the adjacent joints are arranged separately, which can reduce the friction loss caused by the direct contact between the joints, the plurality of spring members are fixedly connected between the adjacent joints, which can realize the connection of the separated joints to avoid the friction loss caused by the direct contact, and on the other hand, the weight of the whole tail body is reduced, which effectively solves the problem of friction loss.

[0016] Furthermore, the multiple sets of springs can constrain the downward position of adjacent joints caused by gravity, and the multiple sets of spring components can also provide a certain elastic force to adjacent joints, maintaining the distance balance between adjacent joints while making the tail body have obvious elasticity, which can realize the rotational connection between joints, so that the joints of the crocodile robot's tail move in the water in a "sine wave" shape, similar to the swinging pattern of a real crocodile's tail, improving the overall swimming stability and achieving a higher degree of simulation of the swinging motion.

[0017] Furthermore, since the tail body is mounted on the drive device, and the rope drive mechanism is connected to both sides of the tail body respectively, during application, the drive device transmits and controls the rope drive mechanism to drive. Under the transmission of the drive device, the rope drive mechanisms on both sides of the tail body drive the tail body to swing. Through the cooperation between the rope drive mechanism and the tail body, the control difficulty is reduced, thereby realizing the tail body to swing action with fewer drive motors.

[0018] In summary, under the drive of the rope mechanism, the joints that are separated in the entire tail body rotate through multiple sets of spring components, thereby achieving the purpose of controlling the tail of the alligator robot to swing its tail with fewer drive motors, and completely solving the problem that existing alligator robots require multiple motors to control the tail swing. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure provided by the first embodiment of the present invention;

[0021] Figure 2 This is a top view of the overall structure provided by the first embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the outer shell structure provided in the first embodiment of the present invention;

[0023] Figure 4 This is a partial schematic diagram of the joint structure provided in the first embodiment of the present invention. Figure 1 ;

[0024] Figure 5 This is a partial schematic diagram of the joint structure provided in the first embodiment of the present invention. Figure 2 ;

[0025] Figure 6 is a schematic diagram of the overall structure provided by the second embodiment of the present application;

[0026] Figure 7 is a schematic diagram of the Adams analysis assembly provided by the present application;

[0027] Figure 8 is a schematic diagram of the Adams analysis provided by the present application Figure 1 ;

[0028] Figure 9 is a schematic diagram of the Adams analysis provided by the present application Figure 2 .

[0029] Reference signs are as follows:

[0030] 1, driving device; 10, rope driving mechanism; 100, motor; 101, rocker; 102, driving rope; 11, shell; 110, insertion hole; 111, control element mounting hole; 112, rope mounting hole; 113, mounting clamping position;

[0031] 2, tail body; 20, joint; 200, arc plate; 2000, convex body; 201, axial rod; 202, radial rod; 21, spring member; 210, first spring; 211, second spring; 212, third spring. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application.

[0033] In the prior art, the multi-motor control tail swing mode of the crocodile robot tail has the following defects: 1. Friction loss problem, that is, under the control of multiple motors, the bearings of each motor need to be regularly lubricated and maintained, and when the lubricating oil is added too little, the motor bearing will not run smoothly, the friction loss will increase, and when the lubricating oil is added too much, the friction torque will increase, the temperature will rise, and the motor will fail. Under the control of a single motor, the rotating structures in direct contact with each other also have a large friction loss after multiple rotations, which affects the long-term use of the crocodile robot tail; 2. The swing is not realistic, that is, in the prior art, the motors are distributed on the tail structure, which causes the trunk to move laterally under the action of inertia, thereby reducing the stability of the overall swimming and affecting the simulation of the swing; 3. The control difficulty is high, that is, multiple motors are needed to cooperate to control the swing of the crocodile robot tail, and once a motor fails, the specified crocodile robot tail swing curve control cannot be completed, and the control difficulty is high; 4. The tension structure has not been fully studied, that is, the swing mechanism of the tension structure in water is still insufficient, and how to achieve better swing effect through stiffness design and drive design has not been systematically studied in the literature.

[0034] In order to solve the above problems, the tail structure of the crocodile robot is improved by three technical features; 1. The joints in the tail body are arranged in sequence on the same axis without direct contact between the joints, which reduces the friction consumption between them and effectively reduces the friction loss; 2. A plurality of spring members are rotatably connected between adjacent joints, and the plurality of spring members cooperate to enable the adjacent joints to be rotatably connected, and the joints move in water in a "sine wave" shape, improving the simulation degree of the tail swing; 3. The rope drive mechanism is drivingly connected to the tail body, and the control efficiency is improved by using a small number of motors to control the tail body.

[0035] Specifically, the present application provides a crocodile robot tail, as shown in the first embodiment of the present application Figures 1 to 9 As shown, it comprises a driving device 1 and a tail body 2; the driving device 1 comprises a rope drive mechanism 10, the tail body 2 is installed on the driving device 1, and the rope drive mechanism 10 is connected to the two sides of the tail body 2 respectively, and the rope drive mechanism 10 is used to drive the tail body 2 to swing; the tail body 2 comprises a plurality of joints 20 and a plurality of spring members 21; the plurality of joints 20 are arranged in sequence on the same axis, and a plurality of spring members 21 are fixedly connected between adjacent joints 20, and the plurality of spring members 21 are used to realize the rotational connection between adjacent joints 20.

[0036] In this application, the multiple joints 20 are arranged separately from each other. In the prior art, the multiple joints 20 are usually directly connected. When the joints 20 are directly connected, friction will be generated at the connection point of the two joints 20 due to rotation, which will lead to frictional loss. However, with this arrangement, the separate joints 20 can avoid frictional loss between the joints 20 and improve the service life of the tail of the crocodile robot.

[0037] When applied, after the rope drive mechanism 10 in the drive device 1 performs a tensioning motion, it will cause the local rotation center of the joint 20 in the tail body 2 to move. The presence of multiple sets of spring components 21 causes the joint 20 to rotate around the corresponding local rotation center. By adjusting the output rotation frequency of the corresponding drive device 1, the specified curved oscillation can be completed. That is, the movement of the crocodile robot's tail in the water is in the shape of a "sine wave", which is similar to the oscillation pattern of a real crocodile's tail. It can also effectively reduce friction loss, improve control efficiency, and solve the problems caused by the control of multiple motors 100 in the prior art.

[0038] Regarding the aforementioned tail section 2, as... Figure 1 , Figure 4 and Figure 5 As shown, the tail body 2 includes five separately arranged joints 20 and three sets of spring components 21 between the joints 20. Through the cooperation of the separate joints 20 and the spring components 21, the tail body 2 can realize the "sine wave" swing of the tail structure under the drive of a single drive device 1, which can realistically imitate the swinging pattern of the crocodile tail.

[0039] For joint 20, such as Figure 1 , Figure 2 and Figure 4 As shown, each joint 20 includes an arc-shaped plate 200, an axial rod 201, and a radial rod 202. The outer arc surface of the arc-shaped plate 200 is connected and fixed to the axial rod 201, and both sides of the arc-shaped plate 200 are connected and fixed to the radial rods 202. The two radial rods 202 are arranged on the same vertical axis. With this arrangement, each joint 20 consists of three axial structures, i.e. Figure 4 The axial rod 201 in the left and right axes, the radial rod 202 in the up and down axes, and the arc plate 200 in the inner and outer axes have a structure similar to the joint 20 in the crocodile tail, which realizes a high degree of biomimicry of the crocodile tail structure. In addition, the structure of the joint 20 provides a structural basis for the connection of multiple sets of spring components 21.

[0040] The outer arc surface of the arc-shaped plate 200 is further connected and fixed with a convex body 2000, the convex body 2000 gradually widens in the direction away from the driving device 1, the outer arc surface of the convex body 2000 is further provided with a through hole, the through hole is connected and fixed with the axial rod 201, and the arc-shaped structure of the arc-shaped plate 200 in the left-right axial direction is arranged, so that the joint 20 has better bionics.

[0041] It should be noted that the arc-shaped plate 200 is provided with a pair of oppositely arranged first convex walls at both ends, the two first convex walls are provided with first through holes, and the two first through holes are respectively used for connecting and fixing the first spring 210 and the second spring 211; the end of the axial rod 201 is provided with a pair of oppositely arranged second convex walls, the two second convex walls are provided with second through holes, and the two second through holes are used for connecting and fixing the second spring 211; the end of the radial rod 202 is provided with a pair of oppositely arranged third convex walls, the two third convex walls are provided with third through holes, and the two third through holes are used for connecting and fixing the third spring 212.

[0042] Moreover, the design of the convex body 2000 provides mounting positions for some elements and effective loads, improves the space utilization rate of the bionic crocodile tail without affecting the performance, for example, a small power supply can be installed on the flat platform of the convex body by imitating the idea of loading fuel on the wings of an airplane, the power supplies on multiple joints are connected in series to supply power to part of the robot equipment, which can improve the endurance while ensuring the bionic performance. Or install a backup small signal exchange device and a microprocessor on the convex body, when the head of the crocodile robot is damaged and cannot work, the backup elements in the tail can also send signals, which can reduce the probability of losing contact to a certain extent.

[0043] Further, in order to realize the stability of the structure of the joint 20, as shown in Figure 4 , the axial rod 201 and the radial rod 202 are arranged perpendicular to each other, and the connecting line at both ends of the arc-shaped plate 200 is perpendicular to the plane formed by the axial rod 201 and the radial rod 202. Through such arrangement, the axial rod 201 in the left-right axial direction, the radial rod 202 in the up-down axial direction and the arc-shaped plate 200 in the inner-outer axial direction form three axial directions, two of which are perpendicular to each other, the conduction of structural forces is more efficient and stable, and the stability of the structure of the joint 20 is improved.

[0044] For the spring member 21, as shown in Figure 1 , Figure 2 and Figure 5 , the spring member 21 includes the first spring 210, the second spring 211 and the third spring 212, the two first springs 210 are respectively connected and fixed on the two sides of the adjacent arc-shaped plate 200, the two second springs 211 are respectively connected and fixed on the two sides of the adjacent arc-shaped plate 200 and the axial rod 201, and the two third springs 212 are respectively connected and fixed on the ends of the adjacent radial rod 202.

[0045] The two first springs 210 can provide elastic force when the tail body 2 swings, so that the tail body 2 has obvious elasticity. The two second springs 211 provide elastic force between the joints 20 to keep mutual balance at a certain distance when the tail body 2 swings. The two third springs 212 are used to constrain the downward displacement of each joint 20 due to gravity when the tail body 2 swings.

[0046] It should be noted that the force between the springs does not change abruptly, and the five joints 20 connected by the springs have a phase difference in force, resulting in a phase difference in movement. Overall, the tail of the crocodile robot is similar to the real crocodile tail in terms of swing state, i.e., the movement in water is in the shape of a "sine wave".

[0047] It should be noted that when the tail body 2 swings, the adjacent joints 20 will have a tendency to approach each other. The two second springs 211 will generate a larger elastic force to keep the joints 20 at a certain distance from each other to achieve mutual balance due to the approach of the adjacent joints 20.

[0048] Further, in order to achieve faster mutual balance between the joints 20, as shown in Figure 5 The elastic coefficient of the second spring 211 is greater than that of the first spring 210 and the third spring 212. Through such a setting, the second spring 211 is elastic, and can react in time when the relative position between the joints 20 changes.

[0049] It should be noted that due to the relatively large elastic coefficient of the second spring 211, when the disturbance is transmitted to the corresponding joint 20, the left and right second springs 211 at the center of rotation are slightly stretched, but the force does not act on the same straight line, generating a small torque that hinders rotation, so that this local rotation is not too violent, ensuring that the disturbance is transmitted relatively slowly and continuously.

[0050] Further, in order to achieve the elastic balance between the springs, the ratio of the elastic coefficient of the first spring 210, the elastic coefficient of the second spring 211 and the elastic coefficient of the third spring 212 is 0.3:2:1 to 0.8:4:1.

[0051] Wherein, since the third spring 212 mainly plays a role in balancing the gravity of the tail structure, based on the moment balance, the elastic coefficient k3 of the third spring 212 can be calculated to be about k3 = 120 ~ 165 * m0 (kN / m), m0 is the mass of a single joint (unit: kg); the elastic coefficients of the other two springs are determined by the elastic coefficient k3 of the third spring 212; the elastic coefficient k2 of the second spring 211 is 2 ~ 4 times the elastic coefficient of the third spring 212, that is, k2 = 2 ~ 4 * k3; the elastic coefficient k1 of the first spring 210 has a great influence on the overall swing stiffness, and can be flexibly adjusted according to needs, and can be 0.3 to 0.8 times the third spring, that is, k1 = 0.3 ~ 0.8 * k3.

[0052] It should be pointed out that the determination of the elastic coefficients among the three springs is first to determine the elastic coefficient of the third spring 212 according to the mass of a single joint, and then to determine the elastic coefficients of the first spring 210 and the second spring 211 according to the elastic coefficient of the third spring 212, that is, to maintain the following relationship:

[0053] 120m0≤k3≤165m0, 0.3k3≤k1≤0.8k3, 2k3≤k2≤4k3

[0054] (k1, k2 and k3 are in kN / m, and m0 is in kg)

[0055] For example, the mass of a single joint is 0.03 kg. The elastic coefficient k3 of the third spring 212 is 3.6 ~ 4.95 kN / m. The elastic coefficient range of the first spring 210 and the second spring 211 can be calculated from the above formula.

[0056] Therefore, when the tail body 2 is applied, the joint 20 away from the driving device is controlled to rotate along the local center between the joint 20 and the joint 20 after the contraction of the rope driving mechanism 10, which drives the elastic deformation of the two first springs 210 and the two third springs 212 connected with the joint 20, and generates disturbance to the next joint 20. However, this disturbance needs to wait for the elastic deformation of the spring to be transmitted, so there is a difference between the stress phase and the movement phase among the five joints 20, resulting in different speeds of each joint 20, that is, different water resistance at the same time, so that the impact force of water on the adjacent joints 20 in the medial-lateral direction is different, and then the adjacent joints 20 move in the medial-lateral direction. Finally, the movement of the entire crocodile robot tail in the water presents a "sine wave" shape. Figure 1

[0057] Regarding the above driving device 1, such as Figure 1 , Figure 2 and Figure 3 ​As shown, the driving device 1 comprises a shell 11 and a rope driving mechanism 10, the shell 11 is provided with a fixed installation clamping position 113, the fixed installation clamping position 113 is installed and fixed with the rope driving mechanism 10, the rope driving mechanism 10 controls the swing of the joint 20 of the tail body 2, and the specified curve swing can be completed.

[0058] For the rope driving mechanism 10, as shown in the figure, Figure 2 As shown, the rope driving mechanism 10 comprises a driving rope 102, a motor 100 and a rocker 101, the shell 11 is connected and fixed with the motor 100, the motor 100 is drivingly connected with the rocker 101, the two ends of the rocker 101 are respectively connected and fixed with the driving rope 102, and the two driving ropes 102 are arranged in the plurality of first springs 210 on the two sides of the joint 20 to string up a plurality of adjacent first springs 210, and the ends of the two driving ropes 102 away from the driving device 1 are respectively connected and fixed on the two ends of the arc-shaped plate 200 at the tail of the arrangement direction of the joint 20, that is, as shown in the figure, Figure 2 As shown in the figure, the rightmost joint 20 of the tail body 2, through such a setting, the driving rope 102 is affected by the transmission of the motor 100, the driving rope 102 on one side is contracted, and the driving rope 102 on the other side is correspondingly relaxed, and the mutual cooperation can drive and control the rotation of the joint 20, so as to control the swing of the whole tail body 2.

[0059] Among them, the shell 11 is connected and fixed with the motor 100, the motor 100 drives the rocker 101, and the two ends of the rocker 101 are respectively connected and fixed with the rope driving mechanism 10, through such a setting, only by adjusting the rotation frequency of the single motor 100, the swing frequency of the rope driving mechanism 10 can be controlled, that is, the specified curve swing can be completed.

[0060] It should be pointed out that the one cycle rotation of the motor 100 is the balance position-rotation away from the balance position-return to the balance position, and the motor 100 includes but is not limited to a servo motor 100, and those skilled in the art can select according to the actual situation.

[0061] For the shell 11, as shown in the figure, Figure 2 As shown, the side wall of the shell 11 is provided with a jack 110, a control element mounting hole 111 and a rope mounting hole 112, the jack 110 is connected and fixed with the convex body 2000 adjacent to the driving device 1, the rope mounting hole 112 is used for installing the driving rope 102 of the rope driving mechanism 10, so that the driving rope 102 in the shell can be connected with the joint 20 on the tail body 2 through the rope mounting hole 112, and the control element mounting hole 111 is used for installing the control element to be connected with the motor 100, through such a setting, the installation and fixed transmission connection of the driving device 1 and the tail body 2 are realized.

[0062] In application, as shown in the figure, Figure 1As shown, the rope-driven mechanism 10 drives the drive rope 102 to rotate the arc plate 200 connected to it to one side. At the same time, the joint 20 will rotate around its local rotation center. This causes the two first springs 210 on the inner and outer sides of the joint 20 to be stretched and compressed respectively. At this time, the force balance at both ends of the arc plate 200 is disrupted, thereby generating a disturbance to the next joint 20. However, since the elastic coefficient of the second spring 211 is relatively large, when the disturbance is transmitted to the corresponding joint 20, the second springs 211 on both sides at the rotation center are slightly stretched, but the force does not act on the same straight line, generating a small torque that resists the rotation. This makes the local rotation not too violent, ensuring that the disturbance transmission is relatively slow and continuous. Overall, the movement of the crocodile robot's tail in the water is in the shape of a "sine wave", which is similar to the swinging pattern of a real crocodile's tail.

[0063] Example 2

[0064] This invention provides a second embodiment of a crocodile-like robot tail, such as... Figure 6 It is basically the same as the first embodiment, except that the drive rope 102 is not connected to the arc plate 200 of the rightmost joint 20, but to both ends of the arc plate 200 of the second joint 20 from the right.

[0065] With this configuration, the tail section 2 includes an active segment and a driven segment. The active segment is the part of the tail section 2 with drive ropes 102 on both sides of the joint 20. The joint 20 rotates when directly driven by the drive ropes 102. Figure 6 The first to fifth joints 20 from the left; the driven section, i.e., the tail body 2 part without drive ropes 102 on both sides of joint 20, this section of joint 20 is not directly driven by drive ropes 102, i.e. Figure 6 The sixth joint 20 from the left in the middle is driven by the previous joint 20, which enables the design of a robot with arbitrary tail length and strong structural scalability.

[0066] Based on the methods described in the first and second embodiments above, those skilled in the art can set the connection and fixing relationship between the drive rope 102 and any arc-shaped plate 200 according to actual needs, as shown in the first embodiment, referring to... Figure 1 and Figure 2 The drive rope 102 is connected to the rightmost joint 20. The tail body 2 is entirely driven, enabling active drive of the entire tail body 2. Alternatively, it can be as shown in the second embodiment, referring to... Figure 6 The drive rope 102 is connected to the second joint 20 from the right. The tail body 2 is divided into an active section and a driven section. The length of the driven section of the tail body 2 can be increased or decreased according to the needs of those skilled in the art.

[0067] From the above, the basic structure of the present application, the following will be described in detail from the power principle analysis.

[0068] Adams analysis assembly (Automatic Dynamic Analysis of Mechanical Systems, mechanical system dynamics automatic analysis) as shown in Figure 7 , dynamic response analysis is carried out by Adams (Automatic Dynamic Analysis of Mechanical Systems, mechanical system dynamics automatic analysis), as shown in Figure 8 and Figure 9 , first add multiple springs, kinematic pairs and constraint forces, wherein the constraint force is a pulling force parallel to the trunk direction and directed to the motor direction, the kinematic pairs include the spherical pairs between the joints (i.e. Figure 2 the arc plate 200 and the convex body 2000 in ), and damping simulation of the water environment is applied, then two input channels and their exciters are established to generate vibration and a kinematic input channel and its exciter, an output channel is established, and then the model is tested. A system modal diagram and the specific values of each point frequency are shown in the following figure, the animation shows the inherent mode, and the i-th mode refers to the relative displacement (or amplitude) of each coordinate when the system is doing the i-th main vibration. The first four orders are over-damped, and the rest are under-damped. It can be seen that the third and fourth order modal vibration modes have a greater impact.

[0069] The above is the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements are also considered to be within the scope of the present application.

Claims

1. A tail of a crocodile-like robot, characterized in that, a driving device and a tail body are included; the driving device includes a rope driving mechanism, the tail body is mounted on the driving device, and the rope driving mechanism is respectively connected to the two sides of the tail body to drive the tail body to swing; the tail body includes a plurality of joints and a plurality of spring members; the plurality of joints are arranged on the same axis in sequence, and a plurality of spring members are fixedly connected between adjacent joints, and the plurality of spring members are used to realize the rotational connection between adjacent joints; the spring member includes a first spring, a second spring and a third spring; the joint includes an arc-shaped plate, an axial rod and a radial rod; the first spring is fixedly connected to the two sides of the adjacent arc-shaped plate; the axial rod is fixedly connected to the outer arc surface of the arc-shaped plate, and the second spring is fixedly connected to the two sides of the adjacent arc-shaped plate; the radial rod is fixedly connected to the two side planes of the arc-shaped plate, and the two radial rods are arranged on the same axis, and the third spring is fixedly connected to the end of the adjacent radial rod; the elastic coefficient of the second spring is greater than the elastic coefficients of the first spring and the third spring. 2.The tail of the crocodile-like robot according to claim 1, characterized in that, the ratio of the elastic coefficients of the first spring, the second spring and the third spring is 0.3:2:1 to 0.8:4:

1.

3. The crocodile-like robot tail according to claim 1, wherein the axial rod and the radial rod are arranged perpendicular to each other. 4.The tail of the crocodile-like robot according to claim 1, characterized in that, the outer arc surface of the arc-shaped plate is further fixedly connected with a convex body, and the convex body gradually widens away from the driving device. 5.The tail of the crocodile-like robot according to claim 4, characterized in that, a through hole is arranged on the outer arc surface of the convex body, and the axial rod is fixedly connected to the through hole. 6.The tail of the crocodile-like robot according to claim 4, characterized in that, the driving device is further provided with a shell, a side wall of the shell is provided with a bushing, and the bushing is fixedly connected to the convex body adjacent to the driving device. 7.The tail of the crocodile-like robot according to claim 6, characterized in that, the rope driving mechanism includes a motor, a rocker and a driving rope; the motor and the rocker are fixedly connected to the shell, the motor is drivingly connected to the rocker, the two ends of the rocker are respectively fixedly connected to the driving rope, and the driving rope is fixedly connected to the two ends of any arc-shaped plate.

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