JP7843549B2 - Ultrasonic direct-drive amphibious mobile robot and its drive method - Google Patents

Description

This invention relates to the technical field of amphibious mobile robots, and more particularly to an ultrasonic direct-drive amphibious mobile robot and its drive method.

Amphibious mobile robots possess the ability to operate in different media, such as water and land, and can move freely between these different media. They are widely applied in fields such as coastal environment monitoring, environmental exploration, and unmanned reconnaissance. Their ability to operate in different media allows them to move freely underwater and on land, adapting to complex water/land environments. Furthermore, by equipping amphibious mobile robots with remote control and navigation capabilities, risks in dangerous environments can be reduced, improving the efficiency and safety of coastal operations. However, due to their operating principle, conventional amphibious mobile robots generate noise and bubbles in the water and surrounding environment during underwater operations. In delicate environments requiring quiet operation, this noise and bubbles make the robot more easily tracked, reducing its concealment.

To meet the needs of various situations, several amphibious robots are currently under development. For example, Chinese patent document CN109017179A proposes an amphibious fire truck for use in firefighting operations, and Chinese patent document CN106394541A proposes an amphibious planing boat. Many conventional amphibious robots are designed based on drive systems such as propellers, wheelsets, and crawlers, and have powerful characteristics such as high speed and high load capacity. However, it is clear that the output characteristics of propellers and wheelsets make amphibious robots based on this design prone to generating and tracking noise. When a propeller rotates, small bubbles are formed due to the combined action of the interaction between the blades and the water and the vibration of the blades. The pressure from the resulting bust changes can be converted into low-frequency sound waves, causing noise. In addition, tip vortices that cause turbulence can be formed at the ends of the propeller blades. In these turbulent and vorticous flows, gases in the water are mixed to form bubbles, and the turbulence itself also generates noise. These noises and bubbles that appear on the water surface, indicating operational traces, can also be tracked by robots, making concealed movement and work difficult.

Regarding the power source for propellers and wheelsets, one method is to employ an internal combustion engine powered by gasoline or diesel. While this method offers superior power and adaptability to harsh environments, it suffers from high noise levels and environmental pollution, making it less effective in applications such as environmental monitoring and unmanned reconnaissance, as it negatively impacts surveillance and makes the robot easily detectable. Another method involves employing battery-powered motors. While this method reduces noise from the amphibious robot's power source, it is difficult to completely eliminate noise from the interaction between the propeller and water, leaving operational traces. Consequently, conventional drive systems for amphibious robots suffer from high noise, high energy consumption, environmental interference, and easy tracking, resulting in limited applicability in fields such as reconnaissance.

As described above, conventional amphibious mobile robots employing propellers, wheelsets, and crawlers as drive systems have several drawbacks: they generate significant operating noise, leave obvious traces, interfere with environmental exploration, and can easily detect the robot's presence. Furthermore, using propellers as an underwater drive system leads to the formation of air bubble zones behind the robot, resulting in high repair and maintenance costs due to propeller cavitation. Additionally, when employing a multi-stage transmission structure linked to an internal combustion engine or motor, the multi-stage transmission from the energy source to the drive mechanism results in significant energy loss, low conversion efficiency from propeller rotational power to forward motion, and high power loss. Moreover, the drive structure itself is bulky and heavy.

To solve the above problems, the present invention proposes an ultrasonically direct-driven amphibious mobile robot and its driving method. By exciting the primary expansion/contraction mode in the thickness direction of the vibrating body of the underwater ultrasonic actuator and the primary deflection mode of the vibrating body of the land-based ultrasonic actuator, the robot is driven to move in water or on land, thereby solving problems such as the high operating noise and obvious operating traces of conventional amphibious robots.

To achieve the above objectives, the present invention employs the following technical approach.
In the first embodiment, the present invention includes a cabin, a drive control circuit provided inside the cabin, an underwater ultrasonic actuator provided at the rear end of the cabin, and a land-based ultrasonic actuator provided at the bottom end of the cabin, wherein both the underwater ultrasonic actuator and the land-based ultrasonic actuator are electrically connected to the drive control circuit.
The aforementioned land-based ultrasonic actuator includes a first case and a first vibrator and a second vibrator provided on both sides of the first case, the first vibrator and the second vibrator each being provided with a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet, and both the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are electrically connected to a drive control circuit.
The underwater ultrasonic actuator includes a second case and a third vibrating body provided within the second case.
The aforementioned drive control circuit is used to drive the amphibious mobile robot to travel underwater by applying a drive voltage to the third vibrator, thereby exciting vibrations in the primary expansion/contraction mode in the thickness direction of the third vibrator, generating ultrasonic waves of the same frequency in water, and generating thrust through the interaction of ultrasonic waves and water.
The aforementioned drive control circuit is used to drive the amphibious mobile robot on land by applying a drive voltage to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, thereby exciting vibrations in the primary deflection mode of the first vibrator and the second vibrator, respectively, and provides an ultrasonic direct-drive amphibious mobile robot.

As an optional embodiment, underwater ultrasonic actuators are provided on both sides of the rear end of the cabin. By applying different magnitude drive voltages to the third vibrators of the two underwater ultrasonic actuators via a drive control circuit, and by applying different magnitude drive voltages to the first and second vibrators via the drive control circuit, acceleration/deceleration and differential turning motion in water or on land are controlled differentially.

As an optional embodiment, the motion direction of the amphibious mobile robot and the thrust of the underwater ultrasonic actuator and the land-based ultrasonic actuator are controlled in a closed-loop manner. Specifically, this includes setting a target motion direction angle and target thrust, collecting the current motion direction angle and actuator thrust, feeding back the current motion direction angle and acceleration, obtaining an error angle from the target motion direction angle and the current motion direction angle, calculating acceleration from the error angle using a direction PID controller, obtaining an error acceleration from the fed-back acceleration, and then feedback-controlling the thrust generated by the underwater ultrasonic actuator and the land-based ultrasonic actuator using a thrust PID controller.

In an optional embodiment, the cabin is further provided with a battery pack for outputting power supply, which is connected to a drive control circuit. The drive control circuit converts the output of the power supply into a drive voltage and is used to apply it to the third vibrator, or the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet.

In an optional embodiment, the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are provided with magnetic adsorption contacts, and the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are electrically connected to the drive control circuit by the magnetic adsorption contacts.

In one selectable embodiment, the third vibrating body is electrically connected to the drive control circuit via magnetic attraction contacts, and a vibration-damping rubber ring is provided on the third vibrating body.

As an optional embodiment, the third vibrating body is a piezoelectric ceramic that serves as both an excitation source and a vibrating body.

As an optional embodiment, the third vibrating body is a cylindrical sheet-shaped piezoelectric ceramic or an arc-shaped piezoelectric ceramic.

As an optional embodiment, the driving frequency band of the underwater ultrasonic actuator is in the MHz range, and the driving frequency band of the land-based ultrasonic actuator is in the kHz range.

In an optional embodiment, the land-based ultrasonic actuator further includes a fixed cover, with fixed rods provided at two nodes in the primary deflection mode of the first and second vibrators. The first case is provided with a groove with an open upper end where the fixed rods are positioned. This groove forms a closed groove with the fixed cover, and the fixed rods are tightly fitted with the first and second vibrators, while the fixed rods are gap-fitted with the first case and fixed cover.

In an optional embodiment, the drive control circuit is further used to receive control commands and select to enter a different operating mode according to the control command. The operating modes include automatic mode, water surface mode, and land mode. In the different modes, the water level sensor detects whether the amphibious mobile robot is in water or not. If it is in water, the underwater ultrasonic actuator is activated; otherwise, the land ultrasonic actuator is activated. In water surface mode, if the water level sensor detects that the amphibious mobile robot is not in water, a non-water surface error command is returned. In land mode, if the water level sensor detects that the amphibious mobile robot is in water, a non-land error command is returned.

In a second embodiment, the present invention is
The process involves applying a drive voltage to the third vibrator of an underwater ultrasonic actuator during underwater travel, thereby exciting vibrations in the primary expansion/contraction mode in the thickness direction of the third vibrator, generating ultrasonic waves of the same frequency in the water, generating thrust through interaction between the ultrasonic waves and water, and driving the underwater movement of the amphibious mobile robot.
The present invention provides a method for driving an ultrasonically direct-driven amphibious mobile robot according to a first embodiment, which includes the step of applying a driving voltage to a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet of a land-use ultrasonic actuator during land travel to excite vibrations in the primary deflection mode of the first vibrator and the second vibrator, respectively, and thereby driving the land travel of the amphibious mobile robot.

The beneficial effects of the present invention compared to the prior art are as follows:
This invention provides an ultrasonically driven amphibious mobile robot and a driving method thereof, which drives the robot's movement in water or on land by exciting the primary expansion/contraction mode in the thickness direction of the vibrating body of an underwater ultrasonic actuator and the primary deflection mode of the vibrating body of a land-based ultrasonic actuator. In a water medium, the high-frequency ultrasonic waves emitted by the underwater ultrasonic actuator propagate backward through the water medium and have strong directionality. The ultrasonic waves and water interact to generate an interactional thrust, which drives the robot's forward movement. During movement, the vibrating body of the underwater ultrasonic actuator does not undergo large mechanical displacement movements, and because the direction in which the ultrasonic waves apply thrust to the water flow is clear, no bubbles are generated in the water, the thrust is generated in a laminar flow, and no obvious traces are left on the water surface. Furthermore, because the ultrasonic waves form a sound field in the water using water as the medium, no ripples are formed on the water surface. On land, the frequency of the ultrasonic waves far exceeds the human audible frequency range, so there is no loud noise, only slight friction noise. This technology solves the problems of conventional amphibious robots, such as high operating noise and easily visible operating traces. It significantly reduces operating noise, enabling silent and traceless operation of amphibious robots, and has application potential in fields such as environmental monitoring and unmanned reconnaissance.

This invention employs a system that directly drives the system using ultrasound both underwater and on land. During operation in water and on land, energy is converted into a flow of electrical energy, vibration, sound waves, and kinetic energy. Only a small amount of energy is dissipated as heat energy, preventing large energy losses. This results in high energy conversion efficiency and low power loss.

The underwater and land-based ultrasonic actuators of this invention exhibit extremely small mechanical displacements at the nm and μm levels, resulting in extremely low wear on the underwater actuator and the absence of bubble generation and cavitation. Furthermore, while the land-based ultrasonic actuator does rub against the ground, the vibrating body in contact with the ground is made of steel, resulting in a slow wear rate and lower repair and maintenance costs for the robot.

The advantages of additional aspects of the present invention are, in part, provided in the following description, in part, evident from the following description, or understood through the practice of the present invention.

The drawings, which constitute a part of the present invention, are intended to further illustrate the invention, and the exemplary embodiments and descriptions thereof are for interpretation purposes only and are not intended to improperly limit the invention.

This is a schematic diagram of the structure of an ultrasonic direct-drive amphibious mobile robot provided in Embodiment 1 of the present invention. This is a schematic diagram of the structure of an underwater ultrasonic actuator provided in Example 1 of the present invention. This is a schematic diagram of the vibration modes of the piezoelectric ceramics in the underwater ultrasonic actuator provided in Embodiment 1 of the present invention. This is a finite element simulation diagram of acoustic-fluid coupling provided in Embodiment 1 of the present invention. This is a schematic diagram of the structure of a land-based ultrasonic actuator provided in Example 1 of the present invention. This is a schematic diagram of the vibration modes of the vibrating body of the land-based ultrasonic actuator provided in Embodiment 1 of the present invention. This is a flowchart of closed-loop control for the direction of motion and thrust of the robot provided in Embodiment 1 of the present invention. This is a flowchart of the control policy for the robot provided in Embodiment 1 of the present invention.

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

It should be noted that the following detailed descriptions are illustrative and intended to further illustrate the invention. Unless otherwise stated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the invention pertains.

It should be noted that the technical terms used herein are solely for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments of the present invention. As used herein, unless otherwise specified in the context, singular forms are intended to include plural forms, and the terms “include” and/or “contain” and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not limited to the explicitly stated steps or units and may include other steps or units not explicitly stated or specific to those processes, methods, products, or apparatus.

The embodiments and technical features of the present invention may be combined with each other, as long as they do not contradict each other.

Example 1
This embodiment provides an ultrasonic direct-drive amphibious mobile robot, as shown in Figure 1, which includes a cabin 5, a drive control circuit 4 located inside the cabin 5, an underwater ultrasonic actuator 1 located at the rear end of the cabin 5, and a land-based ultrasonic actuator 2 located at the bottom end of the cabin 5, with both the underwater ultrasonic actuator 1 and the land-based ultrasonic actuator 2 being electrically connected to the drive control circuit 4.
The aforementioned land-based ultrasonic actuator 2 includes a first case 28 and a first vibrator 21 and a second vibrator 24 provided on both sides of the first case 28, with a first piezoelectric ceramic sheet 22 and a second piezoelectric ceramic sheet 25 provided on the first vibrator 21 and the second vibrator 24, respectively, and both the first piezoelectric ceramic sheet 22 and the second piezoelectric ceramic sheet 25 being electrically connected to a drive control circuit 4.
The underwater ultrasonic actuator 1 includes a second case 13 and a third vibrating body 11 provided inside the second case 13.
The drive control circuit 4 is used to drive the amphibious mobile robot to travel underwater by applying a drive voltage to the third vibrator 11, thereby exciting vibrations in the primary expansion/contraction mode of the third vibrator 11 in the thickness direction, and simultaneously generating ultrasonic waves of the same frequency in the water, thereby generating thrust through the interaction of ultrasonic waves and water.
The drive control circuit 4 is used to drive the amphibious mobile robot to travel on land by applying a drive voltage to the first piezoelectric ceramic sheet 22 and the second piezoelectric ceramic sheet 25, thereby exciting vibrations in the primary deflection mode of the first vibrator 21 and the second vibrator 24, respectively.

In this embodiment, underwater ultrasonic actuators 1 are provided on both sides of the rear end of the cabin 5 to provide thrust for underwater travel of the amphibious mobile robot. By adjusting the amplitude of the drive voltage applied to the third vibrator 11 of the two underwater ultrasonic actuators 1 using the drive control circuit 4, operations such as acceleration, deceleration, and differential turning are controlled.

Specifically, the amplitude of the drive voltage applied to the underwater ultrasonic actuator is controlled by an operational amplifier. As the drive voltage increases, the thrust provided by the underwater ultrasonic actuator increases. By supplying drive voltages of different magnitudes to the underwater ultrasonic actuators on both the left and right sides, differential motion such as acceleration, deceleration, and differential turning is achieved. Simultaneously, the robot's precise movement is achieved by closed-loop control of the direction of motion and the thrust generated by the underwater ultrasonic actuator using an acceleration sensor.

At the bottom of the cabin 5, a land-based ultrasonic actuator 2 is provided to supply thrust for the amphibious mobile robot's land-based movement.

Both the underwater ultrasonic actuator 1 and the land-based ultrasonic actuator 2 are connected to the cabin 5 by screws and are electrically connected to the drive control circuit 4 via waterproof cables and magnetic contacts.

The drive control circuit 4 includes a drive circuit board 41 and a main control circuit board 42. The drive circuit board is a high-voltage drive circuit board, and the purpose of employing a dual circuit board in the drive control circuit 4 is as follows: 1) To separate high-voltage and low-voltage signals and avoid interference. 2) Because the space inside the robot is limited, the dual board arrangement reduces the area of the single circuit board, satisfying the design requirement of achieving a smaller overall robot volume and a more compact structure.

The cabin 5 forms a sealed space with the magnetic adsorption canopy 6, and a battery pack 3 for outputting a predetermined power supply is further provided inside the cabin 5. The battery pack 3 is connected to a drive control circuit 4. The drive control circuit 4 converts the output of the power supply into a drive voltage of a predetermined magnitude and frequency, and applies it to the third vibrator 11 of the underwater ultrasonic actuator 1 and the first and second piezoelectric ceramic sheets of the land-based ultrasonic actuator 2. By exciting the vibrators of the underwater ultrasonic actuator 1 and the land-based ultrasonic actuator 2, the drive control circuit 4 controls the vibration mode of the vibrators.

In this embodiment, as shown in Figure 2, the underwater ultrasonic actuator 1 includes a second case 13, a sealing lid 14, and a third vibrating body 11 provided in the internal space formed by the second case 13 and the sealing lid 14. The third vibrating body 11 is electrically connected to a drive control circuit 4, and a vibration-damping rubber ring 12 is provided on the third vibrating body 11. Here, the third vibrating body 11 is also a piezoelectric ceramic sheet, and this piezoelectric ceramic sheet functions as both an excitation source and a vibrating body, exciting the primary expansion and contraction mode in the thickness direction of the piezoelectric ceramic sheet itself.

Current amphibious mobile robots utilize drive systems other than propellers. These include, for example, traveling wave drive using flexible wave fins designed in Patent Document CN113771566A, jet drive using a piezoelectric pump driven by piezoelectric ceramics proposed in Patent Document CN113772053B, and drive using underwater thrust generated by a vibration-fluid-structure coupling method.

The amphibious mobile robot in this embodiment is similarly driven by a piezoelectric ceramic sheet. However, in this embodiment, high-frequency ultrasonic waves in the MHz frequency band are generated in the water using piezoelectric ceramics, and thrust is directly generated in the water based on the physical phenomenon that ultrasonic waves in this frequency band easily propagate from the actuator (solid) to the water (liquid). This is fundamentally different in principle from the drive method using fins and a pump described in the previous example.

In this embodiment, the third vibrating body 11, as shown in Figure 3, is a cylindrical sheet-shaped piezoelectric ceramic that operates in a primary expansion/contraction mode in the thickness direction and has an operating frequency of 1.65 MHz. When an excitation voltage of the same frequency is applied, the piezoelectric ceramic vibrates in this mode, and ultrasonic waves of the same frequency are generated in the water. In this frequency band, the directivity of the ultrasonic waves is high, the thrust is strong, and a large thrust can be generated.

As one possible embodiment, the third vibrating body 11 may employ an arc-shaped piezoelectric ceramic to concentrate the ultrasonic energy.

As shown in Figure 4, in this embodiment, an acoustic-fluid coupled simulation of underwater ultrasound in the specified frequency band is performed. The left image shows the sound pressure level, where the sound pressure in the center is clearly higher than the sound pressure on either side, indicating high directivity of the sound waves. The right image shows the fluid streamline, where the sound waves in the specified frequency band generate a strong thrust on the water, creating a high-velocity water flow behind the water, as well as generating two vortices.

In this embodiment, as shown in Figure 5, the land-based ultrasonic actuator 2 includes a first vibrating body 21, a first piezoelectric ceramic sheet 22, a fixing rod 23, a second vibrating body 24, a second piezoelectric ceramic sheet 25, a fixing cover 26, a magnetic adsorption contact 27, and a first case 28.

The bottom of the first case 28 is open, and the legs of the vibrating body directly contact the ground to achieve drive. A first vibrating body 21 and a second vibrating body 24 are provided on both sides of the first case 28. A first piezoelectric ceramic sheet 22 is provided on the first vibrating body 21, and a second piezoelectric ceramic sheet 25 is provided on the second vibrating body 24. The first vibrating body 21 and the second vibrating body 24 are used to drive the motion on both the left and right sides, respectively.

Magnetic contacts 27 are provided on the first piezoelectric ceramic sheet 22 and the second piezoelectric ceramic sheet 25, and the first piezoelectric ceramic sheet 22 and the second piezoelectric ceramic sheet 25 are electrically connected to the drive control circuit 4 via the magnetic contacts 27.

To ensure that vibrations from the first vibrating body 21 and the second vibrating body 24 are not transmitted to the first case 28, a fixing rod 23 is fixed to the two nodes of the first vibrating body 21 and the second vibrating body 24 in their primary deflection modes. The fixing rod 23 at one node penetrates both the first vibrating body 21 and the second vibrating body 24, ensuring that the linear displacement of the fixing rod 23 is extremely small, while maintaining a constant rotational displacement.

The first case 28 is provided with a groove at its upper end where the fixing rod 23 is positioned, and this groove forms a closed groove with a part of the fixing lid 26. When assembled, the fixing rod 23 is tightly fitted with the first vibrating body 21 and the second vibrating body 24, and the first case 28 and the fixing lid 26 are gap-fitted, providing rotational space for the fixing rod 23. This significantly reduces the transmission of vibrations from the vibrating body to the case and ensures that the influence of external fixed boundary conditions on the vibration frequency of the primary deflection mode of the first vibrating body 21 and the second vibrating body 24 is minimized.

In this embodiment, the land-based drive unit similarly employs an ultrasonic drive scheme, with a drive frequency band of kHz. The drive principle of the land-based ultrasonic actuator differs from that of the underwater ultrasonic actuator. In the underwater ultrasonic actuator, the piezoelectric ceramic functions as both an excitation source and a vibrating body, exciting the primary expansion and contraction mode in the thickness direction of the piezoelectric ceramic itself. In contrast, in the land-based ultrasonic actuator, as shown in Figure 6, the piezoelectric ceramic sheet is thin and used only as an excitation source, applied to the excitation of the primary deflection mode of the steel first vibrating body 21 and second vibrating body 24, with a frequency of 48.5 kHz. In this mode, the direction of the landing of the legs in contact with the ground generates driving capability in the land-based ultrasonic actuator.

In this embodiment, by adjusting and controlling the drive voltage amplitude for the vibrating elements on both the left and right sides of the land-based ultrasonic actuator using the drive control circuit 4, the land-based ultrasonic actuator can achieve motions such as acceleration, deceleration, and differential rotation.

Specifically, the amplitude of the drive voltage applied to the land-based ultrasonic actuator is controlled by an operational amplifier. As the drive voltage increases, the thrust provided by the land-based ultrasonic actuator increases. By supplying drive voltages of different magnitudes to the vibrating elements on both sides, differential motion such as acceleration, deceleration, and differential turning is achieved. Simultaneously, the robot's precise movement is achieved by closed-loop control of the direction of motion and the thrust generated by the land-based ultrasonic actuator using an acceleration sensor.

In this embodiment, the closed-loop control flow for the robot's motion direction and thrust is as shown in Figure 7. Specifically, the target angle and target thrust are set, the current output angle and output thrust are collected by an acceleration sensor, the angle and linear acceleration are fed back, an error angle is obtained from the target angle and the fed-back angle, the acceleration is calculated from the error angle by the direction PID controller, an error acceleration is obtained from the fed-back acceleration, and then the thrust generated by the actuator is feedback-controlled by the thrust PID controller. Accurate control of the motion direction and thrust is achieved by a cascade PID control algorithm for direction and thrust.

In this embodiment, the drive control circuit integrates a wireless communication module for the robot. The wireless communication module receives control commands from the remote control handle. As shown in Figure 8, upon receiving a command, it analyzes the command and selects a different operating mode. The operating modes include automatic mode, water surface mode, and land mode. In each mode, the water level sensor detects whether the robot is in water. If it is in water, the underwater ultrasonic actuator is activated; otherwise, the land ultrasonic actuator is activated. In water surface mode, if the water level sensor detects that the robot is not in water, a non-water surface error command is returned. In land mode, if the water level sensor detects that the robot is in water, a non-land error command is returned.

It is understood that the dimensions and shape of the vibrating element and the number of piezoelectric ceramics in a land-based ultrasonic actuator may be changed, and other modes may be applied depending on the actual situation.

This embodiment provides an ultrasonically driven amphibious mobile robot. By directly interacting with two media, water and land, using an ultrasonic transducer, a small prototype measuring 117.78 × 105.24 × 56.79 ^mm³ was constructed with a mass of 234.36 g. It employs a wireless communication system and can achieve motion in both water and land, possessing silent and traceless underwater movement capabilities. The prototype can achieve a maximum land speed of 154.66 mm/s and a maximum underwater speed of 54.64 mm/s, with a maximum bottom load of 1357.66 g, which is 5.79 times its own weight. In addition, due to the advantages unique to driving with ultrasonic transducers, a minimum step distance of 6.5 μm can be achieved during land operation, enabling high-precision adjustment of position, attitude, and viewing angle in special reconnaissance environments.

Example 2
This embodiment provides a driving method for the ultrasonic direct-drive amphibious mobile robot described in Embodiment 1.
The process involves applying a drive voltage to the third vibrator of an underwater ultrasonic actuator during underwater travel, thereby exciting vibrations in the primary expansion/contraction mode in the thickness direction of the third vibrator, generating ultrasonic waves of the same frequency in the water, generating thrust through interaction between the ultrasonic waves and water, and driving the underwater movement of the amphibious mobile robot.
The method includes the step of applying a drive voltage to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet of a land-use ultrasonic actuator during land travel to excite vibrations in the primary deflection mode of the first vibrator and the second vibrator, respectively, thereby driving the land travel of the amphibious mobile robot.

The above describes specific embodiments of the present invention with reference to the drawings, but this does not limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications and variations that can be made based on the technical solutions of the present invention without requiring creative effort are also included within the scope of protection of the present invention.

1. Underwater ultrasonic actuator 2. Land ultrasonic actuator 3. Battery pack 4. Drive control circuit 5. Cabin 6. Magnetic adsorption canopy 11. Third vibrator 12. Vibration damping rubber ring 13. Second case 14. Sealing lid 21. First vibrator 22. First piezoelectric ceramic sheet 23. Fixing rod 24. Second vibrator 25. Second piezoelectric ceramic sheet 26. Fixing lid 27. Magnetic adsorption contact 28. First case 41. Drive circuit board 42. Main control circuit board.

Claims (10)

The system includes a cabin, a drive control circuit located inside the cabin, an underwater ultrasonic actuator located at the rear end of the cabin, and a land-based ultrasonic actuator located at the bottom end of the cabin, with both the underwater and land-based ultrasonic actuators being electrically connected to the drive control circuit.
The aforementioned land-based ultrasonic actuator includes a first case and a first vibrator and a second vibrator provided on both sides of the first case, the first vibrator and the second vibrator each being provided with a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet, and both the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are electrically connected to a drive control circuit.
The underwater ultrasonic actuator includes a second case and a third vibrating body provided within the second case.
The aforementioned drive control circuit is used to drive the amphibious mobile robot to travel underwater by applying a drive voltage to the third vibrator, thereby exciting vibrations in the primary expansion/contraction mode in the thickness direction of the third vibrator, generating ultrasonic waves of the same frequency in water, and generating thrust through the interaction of ultrasonic waves and water.
The drive control circuit is used to drive the amphibious mobile robot on land by applying a drive voltage to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, respectively, thereby exciting vibrations in the primary deflection mode of the first vibrator and the second vibrator, and is characterized in that it is used to drive the amphibious mobile robot on land. The ultrasonic direct-drive amphibious mobile robot according to claim 1, characterized in that underwater ultrasonic actuators are provided on both sides of the rear end of the cabin, and different magnitude drive voltages are applied to the third vibrators of the two underwater ultrasonic actuators by a drive control circuit, and different magnitude drive voltages are applied to the first and second vibrators by the drive control circuit, thereby controlling acceleration/deceleration and differential turning motion in water or on land in a differential manner. The ultrasonic direct-drive amphibious mobile robot according to claim 2, characterized in that the direction of motion of the amphibious mobile robot and the thrust of the underwater ultrasonic actuator and the land-based ultrasonic actuator are controlled in a closed-loop manner, specifically by setting a target direction angle and target thrust, collecting the current direction angle and actuator thrust, feeding back the current direction angle and acceleration, obtaining an error angle from the target direction angle and the current direction angle, calculating the acceleration from the error angle using a direction PID controller, obtaining an error acceleration from the fed-back acceleration, and then feedback-controlling the thrust generated by the underwater ultrasonic actuator and the land-based ultrasonic actuator using a thrust PID controller. The ultrasonic direct-drive amphibious mobile robot according to claim 1, further comprising a battery pack for outputting power supply within the cabin, the battery pack connected to a drive control circuit, and the drive control circuit used to convert the output of the power supply into a drive voltage and apply it to the third vibrator, or the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet. The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are provided with magnetic adsorption contacts, and the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are electrically connected to the drive control circuit by the magnetic adsorption contacts.
The third vibrating body is electrically connected to the drive control circuit by magnetic attraction contacts, and the third vibrating body is provided with a vibration-damping rubber ring.
The ultrasonic direct-drive amphibious mobile robot according to claim 1, characterized in that the third vibrating body is a piezoelectric ceramic that is both an excitation source and a vibrating body. The ultrasonic direct-drive amphibious mobile robot according to claim 5, characterized in that the third vibrating element is a cylindrical sheet-shaped piezoelectric ceramic or an arc-shaped piezoelectric ceramic. The driving frequency band of the aforementioned underwater ultrasonic actuator is a frequency band at the MHz level.
The ultrasonic direct-drive amphibious mobile robot according to claim 1, characterized in that the drive frequency band of the aforementioned land-based ultrasonic actuator is a frequency band at the kHz level. The ultrasonic direct-drive amphibious mobile robot according to claim 1, wherein the land-based ultrasonic actuator further includes a fixed cover, and fixed rods are provided at two nodes in the primary deflection mode of the first and second vibrators, and the first case is provided with a groove with an open upper end where the fixed rods are positioned, and this groove forms a closed groove with the fixed cover, and the fixed rods are tightly fitted with the first and second vibrators, and the fixed rods are gap-fitted with the first case and fixed cover. The drive control circuit is further used to receive control commands and select different operating modes according to the control commands, the operating modes including automatic mode, water surface mode, and land mode, and in each mode, the water level sensor detects whether the amphibious mobile robot is in water or not. If it is in water, the underwater ultrasonic actuator is activated; otherwise, the land ultrasonic actuator is activated. In water surface mode, if the water level sensor detects that the amphibious mobile robot is not in water, a non-water surface error command is returned. In land mode, if the water level sensor detects that the amphibious mobile robot is in water, a non-land error command is returned. This is the ultrasonic direct-drive amphibious mobile robot according to claim 1. The process involves applying a drive voltage to the third vibrator of an underwater ultrasonic actuator during underwater travel, thereby exciting vibrations in the primary expansion/contraction mode in the thickness direction of the third vibrator, generating ultrasonic waves of the same frequency in the water, generating thrust through interaction between the ultrasonic waves and water, and driving the underwater movement of the amphibious mobile robot.
A method for driving an ultrasonic direct-drive amphibious mobile robot according to any one of claims 1 to 9, characterized by comprising the step of applying a drive voltage to a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet of a land-use ultrasonic actuator during land travel to excite vibrations in the primary deflection mode of the first vibrator and the second vibrator, respectively, and driving the land travel of the amphibious mobile robot.