A linear ultrasonic motor-based micro-bionic underwater robot and operation method

Abstract

The application relates to a linear ultrasonic motor-based micro bionic underwater robot and a running method, which comprises a bionic cavity and a driving mechanism, the driving mechanism comprises a linear ultrasonic motor assembly, the bionic cavity comprises a plurality of flexible skeletons, a flexible skin, a head base and a tail base, a drain hole is arranged at the center position of the tail base; the two ends of the flexible skeletons are fixedly connected with the head base and the tail base respectively, the plurality of flexible skeletons are evenly distributed between the head base and the tail base to form a cavity support, the flexible skin is arranged outside the cavity support to form a sealed and hollow cavity; in the cavity, the linear ultrasonic motor assembly is fixedly connected with the head base through a connecting piece, the end of a guide piece is fixedly connected with the tail base, and the guide piece is rigidly connected with the linear bearing of the linear ultrasonic motor assembly. The whole structure is simple in structure, small in size, light in mass, high in volume utilization rate, directly driven by the linear ultrasonic motor, greatly reduced in structural complexity, realized in mute operation, and remarkably reduced in production and processing cost, and can be widely applied in the fields of ocean exploration, biological investigation and underwater rescue.

Description

Technical Field

[0001] This invention relates to a miniature biomimetic underwater robot based on a linear ultrasonic motor and its operation method, belonging to the field of underwater robot technology. Background Technology

[0002] In the development of modern underwater robot technology, the performance of the propulsion system has a crucial impact on the robot's overall functionality and application range. Traditional propulsion methods, such as propeller propulsion, while highly efficient, often come with significant noise and complex mechanical structures. These characteristics can limit applications in noise-sensitive and space-constrained environments. Low-noise and highly maneuverable propulsion methods are particularly important in fields such as marine exploration, biological research, and environmental monitoring.

[0003] Obviously, propeller propulsion generates significant water flow disturbance during propulsion, affecting the robot's stability and stealth. In contrast, biological propulsion maintains high efficiency at various speeds. Therefore, biomimetic propulsion technology has become a research direction for improving the propulsion efficiency of underwater robots. For example, patent CN115489706A provides a "squid-inspired flexible jet propulsion device," patent CN113525645A provides a "squid-based biomimetic underwater robot," and patent CN113772059B provides a "multi-degree-of-freedom underwater motion robot inspired by squid and mantis shrimp." These patents all propose biomimetic underwater robots based on jet propulsion. However, they mainly rely on electromagnetic motors combined with linkage mechanisms as the drive mechanism. Electromagnetic motors and linkage mechanisms require multiple mechanical components to achieve motion conversion, and often require additional braking mechanisms to maintain self-locking. This not only increases the complexity of the system but also leads to an increase in overall size, which is not conducive to the miniaturization and lightweighting of underwater robots. At the same time, electromagnetic motors generate noise when they are working, which can be a significant drawback in some applications where concealment is required, affecting the effectiveness of underwater robots.

[0004] Compared with the electromagnetic motors used in the underwater robots mentioned above, ultrasonic motors offer a quiet and efficient solution with their unique driving method. Indeed, patent CN104149953B provides "a robotic jellyfish driven by an embedded cylindrical motor", which uses a cylindrical traveling wave ultrasonic motor, but it still essentially needs to rely on a thrust rod to achieve the robot's underwater operation.

[0005] Therefore, there is an urgent need to provide a new underwater robot that relies on ultrasonic motors and is based on biomimetic propulsion technology, which can reduce the complexity of the structure and achieve silent operation. Summary of the Invention

[0006] This invention provides a miniature biomimetic underwater robot based on a linear ultrasonic motor and its operation method. The linear ultrasonic motor directly drives the expansion and contraction of the biomimetic cavity, and the robot moves by jet propulsion. This greatly reduces the structural complexity, achieves silent operation, and significantly reduces production and processing costs. It can be widely used in marine exploration, biological research, and underwater rescue.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A miniature biomimetic underwater robot based on a linear ultrasonic motor includes a biomimetic cavity and a drive mechanism. The drive mechanism includes a linear ultrasonic motor assembly. The biomimetic cavity includes several flexible skeletons, a flexible skin, a head base, and a tail base. A drainage hole is provided at the center of the tail base.

[0009] The two ends of the flexible skeleton are fixedly connected to the head base and the tail base, respectively. Several flexible skeletons are evenly distributed between the head base and the tail base to form a cavity support. A flexible skin is covered on the outside of the cavity support to form a sealed cavity with a hollow interior.

[0010] Inside the cavity, the linear ultrasonic motor assembly is fixedly connected to the head base via a connector, the end of the guide is fixedly connected to the tail base, and the guide is rigidly connected to the linear bearing of the linear ultrasonic motor assembly.

[0011] When the linear ultrasonic motor assembly is activated, its output linear motion is transmitted to the guide via the linear bearing, which drives the tail base to reciprocate linearly along the central axis of the bionic cavity, allowing the flexible skeleton to switch between compression and release states.

[0012] Furthermore, the linear ultrasonic motor assembly includes a rod, with both ends of the rod respectively secured at the center of an elastic body; a piezoelectric ceramic sheet is respectively attached to the two end faces of each elastic body;

[0013] The slider includes two U-shaped components, with the vertical portion of the components being shorter than the horizontal portion. The horizontal portions of the two components are symmetrically attached to the circumference of the rod. Stepped bosses are provided on the horizontal portions of the components that are attached to the rod. When the two stepped bosses are tightly attached to the circumference of the rod, a rubber ring is fitted on the horizontal portion to clamp the slider onto the rod.

[0014] A linear bearing is sleeved on the optical axis, and the two ends of the optical axis are fixedly connected to the corresponding elastic bodies. There are two optical axes, which are symmetrically distributed with the rod as the center.

[0015] The two vertical parts of each U-shaped component are rigidly connected to the two ends of the corresponding linear bearing, the lateral part of the component is matched and contacted with the axial part of the corresponding linear bearing, and the slider and the linear bearing can move axially relative to the rod.

[0016] Furthermore, a groove is made at the center of the elastomer, and the end of the rod is embedded in the groove to achieve connection;

[0017] A return spring is fitted onto the part of the rod near the head base;

[0018] Furthermore, several head fixing grooves are formed along the circumference of the head base, and the number of head fixing grooves matches the number of flexible skeletons.

[0019] Tail fixing grooves are formed along the circumference of the tail base, and the number of tail fixing grooves matches the number of flexible skeletons;

[0020] The two ends of the flexible skeleton are respectively glued to the corresponding head fixing groove or tail fixing groove;

[0021] The flexible skeleton is provided with at least three supports;

[0022] Furthermore, two threaded holes are symmetrically opened on the head base with the center as the symmetrical point;

[0023] Four evenly distributed through holes are made along the circumference of the elastomer;

[0024] The connector is U-shaped, with a connector through hole on one vertical part and a connector threaded through hole on the other vertical part. The two connectors are arranged opposite each other on the head base, and the vertical part with the connector through hole is fixed in the head threaded hole by screws.

[0025] The vertical portion of the connector with threaded through holes is fixed to the elastomer through hole near the head base by screws. The two elastomer through holes connecting the two connectors are symmetrically distributed relative to the central axis of the elastomer.

[0026] Threaded holes are machined at both ends of the optical axis, which are fixedly connected to the remaining two elastic body through holes by screws. The two elastic body through holes connected by the two optical axes are also symmetrically distributed relative to the central axis of the elastic body.

[0027] The guide is also provided in two parts, including a connecting rod and a guide groove fixed to one end of the connecting rod. The other end of the connecting rod extends vertically outward, and a guide thread through hole is opened on the extended part.

[0028] On the tail base, two tail threaded holes are symmetrically opened with the center as the symmetrical point. The tail threaded holes are close to the outer circumference of the drain hole. Each guide threaded through hole is fixed in the corresponding tail threaded hole by screws. Each guide groove is locked on the linear bearing to form a rigid connection.

[0029] According to the operation method of the micro biomimetic underwater robot based on the linear ultrasonic motor, the piezoelectric ceramic sheet is polarized along the thickness direction and the polarization direction is used as the bonding surface to bond the piezoelectric ceramic sheet to the end face of the elastomer.

[0030] In the initial state of the miniature biomimetic underwater robot, the flexible skeleton is in a bent state, the flexible skin is in an unstretched state, and the return spring is in an uncompressed state.

[0031] When a positive sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet, the linear motion output by the linear ultrasonic motor assembly is transmitted to the guide through the linear bearing, which drives the tail base to move along the central axis of the bionic cavity towards the head base. The compression deformation of the flexible skeleton increases, the flexible skin is in a stretched state, and the return spring is in a compressed state. At this time, the volume of the bionic cavity increases.

[0032] A reverse sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet. The linear motion output by the linear ultrasonic motor assembly is transmitted to the guide through the linear bearing, which drives the tail base to move in the opposite direction to the head base along the central axis of the bionic cavity. The flexible skeleton, flexible skin and return spring release elastic potential energy, and the volume of the bionic cavity decreases.

[0033] Furthermore, a periodically varying sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet, causing the volume of the bionic cavity to change periodically. When the volume of the bionic cavity decreases, water is drained from the drainage hole of the tail base, driving the volume movement of the bionic cavity underwater.

[0034] Furthermore, when a periodically varying sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet, the symmetry of the sawtooth wave voltage is set to 100% and 0%.

[0035] By employing the above technical solutions, the present invention has the following beneficial effects compared to the prior art:

[0036] 1. The micro biomimetic underwater robot based on a linear ultrasonic motor provided by this invention is based on squid jet propulsion. The overall structure of the robot is designed in a biomimetic manner, and the working mode of squid jet propulsion is realized through a simple and compact structural design.

[0037] 2. The micro bionic underwater robot based on a linear ultrasonic motor provided by this invention achieves volume change by directly driving the deformation of a flexible cavity through the linear ultrasonic motor. Compared with the drive structure using a rotary motor and linkage mechanism, the direct drive of the linear ultrasonic motor does not require additional linkage and transmission mechanism and can provide stable and reliable self-locking. At the same time, since the drive signal frequency of the linear ultrasonic motor is in the ultrasonic band, the working noise is much lower than that of the combination of electromagnetic motor and linkage mechanism. It has the advantages of compact structure, smooth operation and low noise. The compact structure can not only reduce the overall size of the robot, but also simplify the internal mechanical structure and reduce the complexity of design and manufacturing.

[0038] 3. The micro bionic underwater robot based on a linear ultrasonic motor provided by the present invention achieves the state switching of compression and release of the entire bionic cavity through the linear motion output by the linear ultrasonic motor. It is equipped with a return spring and a flexible skin. The contraction speed of the flexible cavity is greater than the expansion speed, which can eject liquid in a short time and generate a large thrust.

[0039] 4. The operating method of the micro bionic underwater robot based on the linear ultrasonic motor provided by the present invention achieves periodic changes in the volume of the bionic cavity by applying a periodically changing sawtooth wave voltage to the piezoelectric ceramic sheet of the linear ultrasonic motor assembly, thereby driving the robot to operate. This driving method has high energy conversion efficiency and reduces energy loss caused by the complex intermediate transmission mechanism. Attached Figure Description

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] Figure 1 This is an exploded view of the overall structure of a miniature biomimetic underwater robot based on a linear ultrasonic motor, according to a preferred embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the structure of a linear ultrasonic motor assembly according to a preferred embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the structure of the elastomer according to a preferred embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the slider structure according to a preferred embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the optical axis of a preferred embodiment provided by the present invention;

[0046] Figure 6 This is a schematic diagram of the structure of the connector according to a preferred embodiment of the present invention;

[0047] Figure 7This is a schematic diagram of the structure of the guide member according to a preferred embodiment of the present invention;

[0048] Figure 8 This is a schematic diagram of the head base and tail base of a preferred embodiment of the present invention, wherein 8a is a schematic diagram of the head base structure and 8b is a schematic diagram of the tail base structure.

[0049] Figure 9 This is a schematic diagram of the preferred embodiment of the present invention regarding the driving voltage applied to a micro biomimetic underwater robot;

[0050] Figure 10 This is a schematic diagram of the biomimetic cavity motion principle of a preferred embodiment of the present invention regarding a micro biomimetic underwater robot.

[0051] In the picture:

[0052] 1 is the head base, 1a is the head fixing groove, 1b is the head threaded hole, and 1c is the flexible skin head bonding surface.

[0053] 2 represents the connector, 2a represents the through hole of the connector, and 2b represents the threaded through hole of the connector.

[0054] 3 represents the guide component, 3a represents the guide component groove, and 3b represents the guide component threaded through hole.

[0055] 4 represents the linear ultrasonic motor assembly; 401 is the first piezoelectric ceramic sheet; 402 is the first elastomer; 402a is the first through hole of the elastomer; 402b is the second through hole of the elastomer; 402d is the bonding surface of the first piezoelectric ceramic sheet; 402c is the bonding surface of the second piezoelectric ceramic sheet; 402e is the rod end face mounting groove; 403 is the second piezoelectric ceramic sheet; 404 is the return spring; 405 is the rod; 406 is the slider; 406a is the slider groove; 406b is the stepped boss; 407 is the rubber ring; 408 is the optical axis; 408a is the first threaded hole of the optical axis; 408b is the second threaded hole of the optical axis; 409 is the linear bearing; 410 is the third piezoelectric ceramic sheet; 411 is the second elastomer; and 412 is the fourth piezoelectric ceramic sheet.

[0056] 5 is the tail base, 5a is the tail fixing groove, 5b is the tail threaded hole, 5c is the flexible skin tail bonding surface, and 5d is the drainage hole.

[0057] 6 is a flexible framework.

[0058] 7 is a flexible skin. Detailed Implementation

[0059] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of this application, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of the present invention.

[0060] As described in the background section, jet propulsion, as a biomimetic propulsion technology, has great application potential due to its similarity to the movement of natural organisms such as fish. The main advantages of jet propulsion are its ability to generate significant thrust and its fast response speed. Furthermore, the periodic water intake and exhaust actions of jet propulsion systems effectively reduce water flow noise, thereby improving stealth. However, current jet propulsion technologies primarily rely on electromagnetic motors combined with linkage mechanisms as the drive mechanism, resulting in an increased overall size of the underwater robot and higher noise levels during operation. Even in technologies that consider using ultrasonic motors, a linkage-like mechanism combined with the ultrasonic motor is still used as the drive mechanism. This means that the ultrasonic motor directly drives the load through the inverse piezoelectric effect of the piezoelectric ceramic sheet, failing to utilize the stable and reliable self-locking characteristics that eliminate the need for additional linkages and transmission mechanisms.

[0061] To address the existing challenges, this application provides a miniature biomimetic underwater robot based on a linear ultrasonic motor. The entire underwater robot is designed based on squid jet propulsion and includes a biomimetic cavity. The biomimetic cavity comprises several flexible skeletons 6, a flexible skin 7, a head base 1, and a tail base 5. A drainage hole 5d is provided at the center of the tail base. The two ends of the flexible skeletons are fixedly connected to the head base and the tail base, respectively. Several flexible skeletons are evenly distributed between the head base and the tail base to form a cavity support. A flexible skin is covered on the outside of the cavity support to form a sealed and hollow cavity.

[0062] Once the biomimetic cavity design is complete, a drive mechanism needs to be installed to achieve jet propulsion using biomimetic propulsion technology. The drive mechanism used in this application includes a linear ultrasonic motor assembly 4. Figure 1The diagram shows the overall structure of the preferred configuration of this application. Inside the cavity, the linear ultrasonic motor assembly is fixedly connected to the head base via connector 2, and the end of the guide 3 is fixedly connected to the tail base. The guide is also rigidly connected to the linear bearing 409 of the linear ultrasonic motor assembly. The main advantage of jet propulsion is that it can generate a large thrust and has a fast response speed. Therefore, as long as the linear ultrasonic motor assembly is started, its output linear motion is transmitted to the guide via the linear bearing, driving the tail base to reciprocate linearly along the central axis of the bionic cavity, so that the flexible skeleton switches between compression and release states. Figure 10 As shown in the diagram, when the volume of the bionic cavity decreases, water is drained from the drainage hole at the tail base, which drives the volume movement of the bionic cavity underwater. In addition, because the linear ultrasonic motor assembly drives the bionic cavity through periodic water intake and drainage, water flow noise can be effectively reduced, thereby improving concealment.

[0063] Regarding the specifics of the linear ultrasonic motor assembly, such as Figure 2 As shown, it includes a rod 405, with both ends of the rod respectively fixed at the center of the elastic body; a piezoelectric ceramic sheet is respectively attached to the two end faces of each elastic body. Figure 4 As shown, slider 406 includes two U-shaped components, with the vertical portion of each component shorter than its horizontal portion. The horizontal portions of the two components symmetrically fit against the circumference of the rod. Stepped bosses 406b are provided on the horizontal portions where the components fit against the rod. When the two stepped bosses are tightly fitted against the circumference of the rod, rubber rings 407 are fitted onto the horizontal portions to clamp the slider onto the rod. Linear bearings are fitted onto optical shafts 408, with both ends of the optical shafts fixedly connected to corresponding elastic bodies. There are two optical shafts, symmetrically distributed around the rod. The two vertical portions of each U-shaped component are rigidly connected to the two ends of the corresponding linear bearing, and the horizontal portion of the component matches and contacts the axial portion of the corresponding linear bearing. The slider and the linear bearing can move axially relative to the rod.

[0064] Since the linear ultrasonic motor assembly will drive the tail base to make a reciprocating motion towards the head base after it is started, when the entire bionic cavity switches between compression and release states, the contraction speed of the flexible cavity needs to be greater than the expansion speed. Therefore, a return spring 404 is sleeved on the part of the rod near the head base. The return spring is combined with the flexible skin to spray liquid from the drainage hole of the tail base in a short time, generating a large thrust.

[0065] For ease of description, in this specific embodiment, the two elastomers are defined as a first elastomer 402 and a second elastomer 411, respectively. Figure 2Taking a specific perspective as an example, starting from the left, the first piezoelectric ceramic sheet 401 and the second piezoelectric ceramic sheet 403 are respectively attached to the left and right end faces of the first elastic body, and the third piezoelectric ceramic sheet 410 and the fourth piezoelectric ceramic sheet 412 are respectively attached to the left and right end faces of the second elastic body. Figure 3 Regarding the first elastomer, the first piezoelectric ceramic sheet is adhered to the first piezoelectric ceramic sheet adhesion surface 402d, and the second piezoelectric ceramic sheet is adhered to the second piezoelectric ceramic sheet adhesion surface 402c.

[0066] A groove is made at the center of the elastic body, and the end of the rod is embedded in the groove to achieve connection; in order to better stabilize the rod, rod end face mounting grooves 402e are also provided at the center of the first elastic body and the second elastic body respectively, so as to firmly connect the rod to the elastic body.

[0067] The slider consists of two U-shaped components, such as... Figure 4 As shown, the part that needs to be fitted with the rod in the middle is a trapezoidal boss. The curvature of the trapezoidal boss matches the circumferential curvature of the rod. The two ends of the component are bent outward to form a slider groove 406a. When the two U-shaped components are symmetrically fitted with the circumference of the rod, the rubber ring is fitted in the middle part of the slider to lock the slider onto the rod.

[0068] When the linear ultrasonic motor assembly directly drives the flexible cavity to undergo volume changes, it is necessary to ensure the stability of the elastomer while simultaneously transmitting the linear motion of the linear ultrasonic motor assembly to drive the tail base to perform reciprocating linear motion along the axial direction. Therefore, the micro biomimetic underwater robot structure incorporates linear bearings and guide components. The first elastomer is fixedly connected to the head base via connectors. The specific connection details are as follows: on the head base, two threaded holes 1b are symmetrically opened with the center as the symmetrical point; four evenly distributed elastomer through holes are opened along the circumference of the elastomer. Regarding these four elastomer through holes, as follows... Figure 3 As shown in the cross-sectional view, only the first through hole 402a and the second through hole 402b of the elastic body are visible. The third through hole and the fourth through hole of the elastic body are also evenly distributed on the circumference of the elastic body. The first through hole and the third through hole of the elastic body are symmetrically distributed as one group, and the second through hole and the fourth through hole of the elastic body are symmetrically distributed as another group.

[0069] Figure 6 As shown, the connector is U-shaped, with a connector through hole 2a on one vertical portion and a connector threaded through hole 2b on the other vertical portion. The two connectors are arranged opposite each other on the head base. The vertical portion with the connector through hole is fixed in the head threaded hole by screws; the vertical portion with the connector threaded through hole is fixed to the elastic body through hole near the head base by screws. Figure 5As shown, the two machined threaded holes at both ends of the optical axis are defined as the first threaded hole 408a and the second threaded hole 408b of the optical axis, respectively. They are fixedly connected to the remaining two elastic body through holes by screws. The elastic body through holes mentioned here are the first elastic body through hole, the second elastic body through hole, the third elastic body through hole, and the fourth elastic body through hole. When the first elastic body through hole and the third elastic body through hole are fixedly connected to the threaded through hole of the connector, then the second elastic body through hole and the fourth elastic body through hole serve as the fixed connection part with the optical axis, and vice versa.

[0070] Two guide members are also provided, such as Figure 7 As shown, the guide includes a connecting rod and a guide groove 3a fixed to one end of the connecting rod. The other end of the connecting rod extends vertically outward, and a guide threaded through hole 3b is opened on the extended part. The guide is fixedly connected to the tail base. Therefore, on the tail base, two tail threaded holes 5b are symmetrically opened with the center as the symmetrical point. The tail threaded holes are close to the outer circumference of the drain hole. Each guide threaded through hole is fixed in the corresponding tail threaded hole by a screw. Each guide groove is locked on the linear bearing to form a rigid connection.

[0071] After the bionic cavity is set up, several head fixing grooves 1a are made along the circumference of the head base, the number of head fixing grooves matching the number of flexible skeletons; tail fixing grooves 5a are made along the circumference of the tail base, the number of tail fixing grooves matching the number of flexible skeletons; the two ends of the flexible skeleton are respectively bonded to the corresponding head fixing grooves or tail fixing grooves with epoxy resin; the opening of each groove and hole on the head base and tail base is as follows. Figure 8 As shown, Figure 8 In the diagram, 8a is the head base and 8b is the tail base. At least three flexible frames are typically installed to ensure stability during subsequent expansion and contraction within the bionic cavity. Next, silicone rubber is used to evenly and tightly adhere the inner surface of the flexible skin to the exterior of the frame constructed from the flexible skeleton. Flexible skin head bonding surface 1c and flexible skin tail bonding surface 5c are formed on the end faces of the head base and tail base relative to the interior of the bionic cavity, respectively. Silicone rubber is then used to tightly bond the ends of the flexible skin to the flexible skin head bonding surface and the flexible skin tail bonding surface.

[0072] Thus, the aforementioned miniature bionic underwater robot based on a linear ultrasonic motor solves the problems of large size and mass, and complex structure of existing bionic underwater robots. However, a miniature bionic underwater robot based solely on a linear ultrasonic motor cannot completely achieve the effects of reducing operating noise and generating greater thrust. Therefore, this application also provides a method for operating a miniature bionic underwater robot based on a linear ultrasonic motor. First, regarding the polarization direction of the piezoelectric ceramic sheet, the piezoelectric ceramic sheet is polarized along its thickness direction. In this application, the polarization direction is used as the bonding surface, and the piezoelectric ceramic sheet is bonded to the end face of the elastomer. The other side of the piezoelectric ceramic sheet is the non-bonded surface, which is used to apply voltage so that the linear ultrasonic motor assembly outputs linear motion.

[0073] In the initial state, the flexible skeleton of the miniature biomimetic underwater robot is bent, the flexible skin is unstretched, and the return spring is uncompressed. During the expansion phase of the biomimetic cavity, a positive sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet. The linear motion output by the linear ultrasonic motor assembly is transmitted to the guide via a linear bearing, causing the tail base to move along the central axis of the biomimetic cavity towards the head base. The compression deformation of the flexible skeleton increases, the flexible skin is stretched, and the return spring is compressed, resulting in an increase in the volume of the biomimetic cavity. During the contraction phase, a reverse sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet. The linear motion output by the linear ultrasonic motor assembly is transmitted to the guide via a linear bearing, causing the tail base to move in the opposite direction along the central axis of the biomimetic cavity towards the head base. The flexible skeleton, flexible skin, and return spring release elastic potential energy, causing the volume of the biomimetic cavity to rapidly decrease. Figure 10 As shown. This direct-drive method can provide stable and reliable self-locking without additional linkages and transmission mechanisms. At the same time, the drive signal frequency is in the ultrasonic band, and the operating noise is much lower than that of the combination of electromagnetic motor and linkage mechanism.

[0074] To enable the operation of a miniature biomimetic underwater robot underwater, a periodically varying sawtooth wave voltage is applied to the non-bonded surface of a piezoelectric ceramic sheet. Figure 9 (As shown by the driving voltage), the sawtooth wave voltage symmetry is set to 100% and 0%, and the volume of the bionic cavity changes periodically at the same time. When the volume of the bionic cavity decreases, because the contraction speed of the flexible cavity is greater than the expansion speed, liquid can be ejected from the drainage hole of the tail base in a short time, driving the volume movement of the bionic cavity underwater.

[0075] In summary, the micro bionic underwater robot and its operation method based on a linear ultrasonic motor provided in this application have a simple structure, small size, light weight, and high volume utilization. The use of a linear ultrasonic motor for direct drive greatly reduces structural complexity, enables silent operation, and significantly reduces production and processing costs. It can be widely used in fields such as marine exploration, biological research, and underwater rescue.

[0076] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0077] The meaning of "and / or" as used in this application includes both situations where each exists alone or both exist simultaneously.

[0078] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0079] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A miniature biomimetic underwater robot based on a linear ultrasonic motor, characterized in that: It includes a bionic cavity and a drive mechanism. The drive mechanism includes a linear ultrasonic motor assembly. The bionic cavity includes several flexible skeletons, flexible skin, a head base and a tail base. A drainage hole is opened at the center of the tail base. The two ends of the flexible skeleton are fixedly connected to the head base and the tail base, respectively. Several flexible skeletons are evenly distributed between the head base and the tail base to form a cavity support. A flexible skin is covered on the outside of the cavity support to form a sealed cavity with a hollow interior. Inside the cavity, the linear ultrasonic motor assembly is fixedly connected to the head base via a connector, the end of the guide is fixedly connected to the tail base, and the guide is rigidly connected to the linear bearing of the linear ultrasonic motor assembly. When the linear ultrasonic motor assembly is activated, its output linear motion is transmitted to the guide component through the linear bearing, driving the tail base to reciprocate linearly along the central axis of the bionic cavity, so that the flexible skeleton switches between compression and release states; the linear ultrasonic motor directly drives the deformation of the flexible cavity to achieve its volume change. The linear ultrasonic motor assembly includes a rod, with both ends of the rod respectively secured at the center of an elastic body; a piezoelectric ceramic sheet is respectively attached to the two end faces of each elastic body; The slider includes two U-shaped components, with the vertical portion of the components being shorter than the horizontal portion. The horizontal portions of the two components are symmetrically attached to the circumference of the rod. Stepped bosses are provided on the horizontal portions of the components that are attached to the rod. When the two stepped bosses are tightly attached to the circumference of the rod, a rubber ring is fitted on the horizontal portion to clamp the slider onto the rod. A linear bearing is sleeved on the optical axis, and the two ends of the optical axis are fixedly connected to the corresponding elastic bodies. There are two optical axes, which are symmetrically distributed with the rod as the center. The two vertical parts of each U-shaped component are rigidly connected to the two ends of the corresponding linear bearing, the lateral part of the component is matched and contacted with the axial part of the corresponding linear bearing, and the slider and the linear bearing can move axially relative to the rod.

2. The miniature biomimetic underwater robot based on a linear ultrasonic motor according to claim 1, characterized in that: A groove is made at the center of the elastomer, and the end of the rod is embedded in the groove to achieve connection; A return spring is fitted onto the part of the rod near the head base.

3. The miniature biomimetic underwater robot based on a linear ultrasonic motor according to claim 1, characterized in that: Several head fixing slots are opened along the circumference of the head base, and the number of head fixing slots matches the number of flexible skeletons; Tail fixing grooves are formed along the circumference of the tail base, and the number of tail fixing grooves matches the number of flexible skeletons; The two ends of the flexible skeleton are respectively glued to the corresponding head fixing groove or tail fixing groove; The flexible skeleton is provided with at least three supports.

4. The miniature biomimetic underwater robot based on a linear ultrasonic motor according to claim 1, characterized in that: Two threaded holes are symmetrically opened on the head base with the center as the symmetrical point; Four evenly distributed through holes are made along the circumference of the elastomer; The connector is U-shaped, with a connector through hole on one vertical part and a connector threaded through hole on the other vertical part. The two connectors are arranged opposite each other on the head base, and the vertical part with the connector through hole is fixed in the head threaded hole by screws. The vertical portion of the connector with threaded through holes is fixed to the elastomer through hole near the head base by screws. The two elastomer through holes connecting the two connectors are symmetrically distributed relative to the central axis of the elastomer. Threaded holes are machined at both ends of the optical axis, which are fixedly connected to the remaining two elastic body through holes by screws. The two elastic body through holes connected by the two optical axes are also symmetrically distributed relative to the central axis of the elastic body. The guide is also provided in two parts, including a connecting rod and a guide groove fixed to one end of the connecting rod. The other end of the connecting rod extends vertically outward, and a guide thread through hole is opened on the extended part. On the tail base, two tail threaded holes are symmetrically opened with the center as the symmetrical point. The tail threaded holes are close to the outer circumference of the drain hole. Each guide threaded through hole is fixed in the corresponding tail threaded hole by a screw. Each guide groove is locked on the linear bearing to form a rigid connection.

5. The operation method of the micro biomimetic underwater robot based on a linear ultrasonic motor according to any one of claims 1-4, characterized in that: The piezoelectric ceramic sheet is polarized along the thickness direction, and the polarization direction is used as the bonding surface to bond the piezoelectric ceramic sheet to the end face of the elastomer. In the initial state of the miniature biomimetic underwater robot, the flexible skeleton is in a bent state, the flexible skin is in an unstretched state, and the return spring is in an uncompressed state. When a positive sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet, the linear motion output by the linear ultrasonic motor assembly is transmitted to the guide through the linear bearing, which drives the tail base to move along the central axis of the bionic cavity towards the head base. The compression deformation of the flexible skeleton increases, the flexible skin is in a stretched state, and the return spring is in a compressed state. At this time, the volume of the bionic cavity increases. A reverse sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet. The linear motion output by the linear ultrasonic motor assembly is transmitted to the guide through the linear bearing, which drives the tail base to move in the opposite direction to the head base along the central axis of the bionic cavity. The flexible skeleton, flexible skin and return spring release elastic potential energy, and the volume of the bionic cavity decreases.

6. The operation method of the micro biomimetic underwater robot based on a linear ultrasonic motor according to claim 5, characterized in that: A periodically varying sawtooth wave voltage is applied to the non-bonded surface of the piezoelectric ceramic sheet, causing the volume of the bionic cavity to change periodically. When the volume of the bionic cavity decreases, water is drained from the drainage hole at the tail base, driving the volume movement of the bionic cavity underwater.

7. The operation method of the micro biomimetic underwater robot based on a linear ultrasonic motor according to claim 6, characterized in that: When a periodically varying sawtooth wave voltage is applied to the non-bonded surface of a piezoelectric ceramic sheet, the symmetry of the sawtooth wave voltage is set to 100% and 0%.

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