An ultrasonic direct-driven amphibious mobile robot and actuation method thereof

Abstract

The present invention discloses an ultrasonic direct-driven amphibious mobile robot and an actuation method thereof, which relates to the technical field of amphibious mobile robots, and comprises: an underwater ultrasonic actuator arranged at the rear end of a cabin and an onshore ultrasonic actuator arranged at the bottom end of the cabin. When traveling underwater, a driving voltage is applied to a third vibrator of the underwater ultrasonic actuator to excite the third vibrator to vibrate in a first-order tensile mode in the thickness direction, and ultrasonic waves of the same frequency are generated in water. The ultrasonic waves interact with water to generate thrust, thereby driving the amphibious mobile robot to travel underwater; when traveling on land, a driving voltage is applied to a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet of the onshore ultrasonic actuator to excite the first vibrator and the second vibrator to vibrate in a first-order bending mode, respectively, thereby driving the amphibious mobile robot to travel on land. The invention solves the problems of large running noise and obvious running traces of traditional amphibious robots.

Description

Technical Field

[0001] The invention relates to the technical field of water and land amphibious mobile robots, and in particular to an ultrasonic direct-driven water and land amphibious mobile robot and an actuation method thereof. Background Art

[0002] Amphibious mobile robots have the ability to operate in different media on land and water, and can move freely between different media. They are widely used in offshore environmental monitoring, environmental exploration, unmanned reconnaissance and other fields. Their different media driveability enables them to move freely on water and land, and have the characteristics of adapting to complex water / road environments. In addition, amphibious mobile robots can be equipped with remote operation and autonomous navigation capabilities, which effectively reduces the risk of humans performing tasks in dangerous environments and improves the efficiency and safety of coastal operations. However, due to the limitations of the driving principle, the noise and bubbles generated by traditional amphibious mobile robots when operating in water may interfere with the underwater ecosystem and the surrounding environment. In sensitive environments where silent operation is required, noise and bubbles make the robot relatively easy to track, reducing its concealment.

[0003] In order to meet the needs of various scenarios, a variety of amphibious robots have been developed. For example, Chinese patent document CN109017179A proposes an amphibious fire truck for firefighting operations, and Chinese patent document CN106394541A proposes an amphibious gliding boat. Most traditional amphibious robots are designed based on propellers, wheels, tracks and other driving methods. Although they have strong characteristics such as high speed and high load, the violent output of propellers and wheels makes the amphibious robots designed based on this design have obvious noise and running traces. When the propeller rotates, the interaction between the blades and the water causes the deformation and vibration of the water. This deformation and vibration causes the gas in the water to be sheared and form small bubbles. The pressure pulsation generated can be converted into low-frequency sound waves, resulting in noise. At the same time, sharp vortices may form at the end of the propeller blades. These sharp vortices will cause the generation of turbulence. In these turbulences and vortices, the gas in the water is mixed and bubbles are formed. The turbulence itself will also cause noise and increase the complexity of hydrodynamics. These noises, bubbles and other traces of operation are precisely the reasons why the robot is exposed and tracked.

[0004] In terms of the common power sources for propellers and wheels, one solution is to use an internal combustion engine driven by gasoline or diesel. This solution has obvious advantages in terms of power and adaptability to harsh environments, but the internal combustion engine has high noise and serious environmental pollution. When used in fields such as environmental monitoring and unmanned exploration, it has serious defects that affect monitoring and are easy to be exposed; another solution is to use a battery-driven motor. This solution has good noise control in terms of the power source of amphibious robots, but the noise generated by the interaction between the propeller and water still exists, and the running traces have not been greatly improved. Therefore, the high noise, high energy consumption, interference environment, and easy tracking of amphibious robots with traditional drive methods make it difficult for them to perform well in the field of reconnaissance.

[0005] In summary, traditional amphibious mobile robots use propellers, wheels, tracks, etc. as driving methods, which have high working noise and obvious running traces, which will affect environmental surveys and cause self-exposure and tracking; moreover, the use of propellers as a driving method in water is prone to produce bubble areas at the rear, causing propeller cavitation and high maintenance costs. In addition, the multi-stage transmission structure using internal combustion engines or motors requires multi-stage transmission from the energy source to the drive end, resulting in large energy losses, and the conversion efficiency of the propeller rotation power to the hull forward power is low, resulting in large power losses, and also causing its drive structure to be large in size and mass. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes an ultrasonic direct-drive amphibious mobile robot and an actuation method thereof, which drives the robot to move underwater or on land by exciting the first-order tensile mode of the vibrator of the underwater ultrasonic actuator in the thickness direction and the first-order bending mode of the vibrator of the land ultrasonic actuator, thereby solving the problems of high operating noise and obvious operating traces of traditional amphibious robots.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an ultrasonic direct-driven amphibious mobile robot, comprising: a cabin, a drive control circuit disposed in the cabin, an underwater ultrasonic actuator disposed at the rear end of the cabin, and an onshore ultrasonic actuator disposed at the bottom end of the cabin, wherein both the underwater ultrasonic actuator and the onshore ultrasonic actuator are electrically connected to the drive control circuit;

[0009] The land ultrasonic actuator comprises a first shell, and a first vibrating body and a second vibrating body arranged on both sides of the first shell, the first vibrating body and the second vibrating body are respectively provided with a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet, and the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both electrically connected to the drive control circuit;

[0010] The underwater ultrasonic actuator comprises a second shell and a third vibrating body arranged in the second shell;

[0011] The drive control circuit is used to apply a driving voltage to the third vibrator pair to excite the third vibrator to vibrate in a first-order tensile mode in the thickness direction, and generate ultrasonic waves of the same frequency in water, and the ultrasonic waves and water generate thrust due to interaction, thereby driving the amphibious mobile robot to move underwater;

[0012] The drive control circuit is used to apply a driving voltage to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet to respectively excite the first vibrator and the second vibrator to vibrate in the first-order bending mode, thereby driving the amphibious mobile robot to move on land.

[0013] As an optional implementation, underwater ultrasonic actuators are respectively provided on both sides of the rear end of the cabin, and driving voltages of different magnitudes are applied to the third vibrating bodies of the two underwater ultrasonic actuators through the driving control circuit, and driving voltages of different magnitudes are applied to the first vibrating body and the second vibrating body through the driving control circuit, thereby controlling the acceleration, deceleration and differential turning movements underwater or on land in a differential manner.

[0014] As an optional implementation, the movement direction of the amphibious mobile robot and the thrust of the underwater ultrasonic actuator and the onshore ultrasonic actuator are closed-loop controlled; specifically, the following steps are performed: setting a target movement direction angle and a target thrust, collecting the current movement direction angle and the actuator thrust, and feeding back the current movement direction angle and acceleration; obtaining an error angle according to the target movement direction angle and the current movement direction angle, using a direction PID controller to resolve the acceleration according to the error angle, and obtaining an error acceleration according to the feedback acceleration, and then feedback-controlling the thrust generated by the underwater ultrasonic actuator and the onshore ultrasonic actuator through a thrust PID controller.

[0015] As an optional embodiment, a battery pack for outputting power supply is also provided in the cabin, and the battery pack is connected to the drive control circuit. The drive control circuit is used to convert the output of the power supply into a driving voltage and apply it to the third vibrating body or the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet.

[0016] As an optional implementation, magnetic contacts are provided on the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, and the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are electrically connected to the drive control circuit via the magnetic contacts.

[0017] As an optional implementation, the third vibrating body is electrically connected to the drive control circuit via a magnetic contact, and a vibration-damping rubber ring is provided on the third vibrating body.

[0018] As an optional implementation, the third vibrator is a piezoelectric ceramic, and the piezoelectric ceramic serves as both an excitation source and a vibrator.

[0019] As an optional implementation, the third vibrating body is a cylindrical sheet piezoelectric ceramic or a curved surface piezoelectric ceramic.

[0020] As an optional implementation, the driving frequency band of the underwater ultrasonic actuator is a MHz frequency band; the driving frequency band of the land ultrasonic actuator is a KHz frequency band.

[0021] As an optional embodiment, the land ultrasonic actuator also includes a fixing cover, a fixing rod is provided at two nodes of the first-order bending mode of the first vibrating body and the second vibrating body, a groove open for placing the upper end of the fixing rod is provided on the first shell, and forms a closed groove with the fixing cover, an interference fit is formed between the fixing rod and the first vibrating body and the second vibrating body, and a clearance fit is formed between the fixing rod and the first shell and the fixing cover.

[0022] As an optional implementation, the drive control circuit is also used to receive control instructions and select to enter different working modes according to the control instructions, and the working modes include automatic mode, surface mode and land mode; in different modes, the water level sensor detects whether the amphibious mobile robot is in the water, and if it is in the water, the underwater ultrasonic actuator is started, otherwise the land ultrasonic actuator is started; wherein, if in the surface mode, the water level sensor detects that the amphibious mobile robot is not in the water, and then a non-surface error instruction is returned; if in the land mode, the water level sensor detects that the amphibious mobile robot is in the water, and then a non-land error instruction is returned.

[0023] In a second aspect, the present invention provides an actuation method for the ultrasonic direct-drive amphibious mobile robot according to the first aspect, comprising:

[0024] When traveling underwater, a driving voltage is applied to the third vibrator pair of the underwater ultrasonic actuator to excite the third vibrator to vibrate in the first-order tensile mode in the thickness direction, and ultrasonic waves of the same frequency are generated in the water. The ultrasonic waves interact with the water to generate thrust, thereby driving the amphibious mobile robot to travel underwater;

[0025] When traveling on land, a driving voltage is applied to the first piezoelectric ceramic piece and the second piezoelectric ceramic piece of the land ultrasonic actuator to respectively excite the first vibrator and the second vibrator to vibrate in the first-order bending mode, thereby driving the amphibious mobile robot to travel on land.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention proposes an ultrasonic direct-driven amphibious mobile robot and an actuation method thereof, which drives the robot to move underwater or on land by exciting the first-order tensile mode in the thickness direction of the vibrating body of the underwater ultrasonic actuator and the first-order bending mode of the vibrating body of the onshore ultrasonic actuator. In the water medium, the high-frequency ultrasonic wave generated by the underwater ultrasonic actuator propagates backward with water as the medium, and has strong directivity. The ultrasonic wave interacts with the water to generate an interactive thrust, which pushes the robot forward. During the movement, since the vibrating body of the underwater ultrasonic actuator does not have a large displacement mechanical movement, the ultrasonic wave pushes the water flow in a clear direction, so no bubbles are generated in the water, the water flow is also relatively regular, and no obvious traces are generated on the water surface. The ultrasonic wave forms a sound pressure field with water as the medium underwater, so it will not form sound wave ripples on the water surface. On the ground, the ultrasonic wave frequency is far beyond the human hearing frequency band, there is no large noise, only small friction noise. It solves the problems of high operating noise and obvious operating traces of traditional amphibious robots, significantly reduces operating noise, realizes the silent and traceless operation of amphibious robots, and promotes the further application of amphibious robots in environmental monitoring, unmanned reconnaissance and other fields.

[0028] The present invention adopts a water-land ultrasonic direct drive mode. When running on the water surface and the ground, in the process of energy conversion from electrical energy-vibration-sound wave-kinetic energy, only a small amount of energy is converted into heat energy and dissipated, and there is no other large amount of energy loss link. The energy conversion efficiency is high and the power loss is small.

[0029] In the underwater ultrasonic actuator and the onshore ultrasonic actuator of the present invention, the mechanical displacement of the actuator is extremely small, at the nm and μm levels. Due to the extremely small mechanical displacement, the underwater ultrasonic actuator has extremely small wear, no bubbles are generated, and no cavitation occurs. The onshore ultrasonic actuator has friction with the ground, but the vibrating body in contact with the ground is made of steel, and the wear rate is relatively slow, so that the maintenance cost of the robot is low.

[0030] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 A schematic diagram of the structure of an ultrasonic direct-driven amphibious mobile robot provided in Example 1 of the present invention;

[0033] Figure 2 A schematic diagram of the structure of an underwater ultrasonic actuator provided in Example 1 of the present invention;

[0034] Figure 3 A schematic diagram of the piezoelectric ceramic vibration modes of the underwater ultrasonic actuator provided in Example 1 of the present invention;

[0035] Figure 4 This is a finite element simulation diagram of acoustic-fluid coupling provided in Example 1 of the present invention;

[0036] Figure 5 A schematic diagram of the structure of an onshore ultrasonic actuator provided in Example 1 of the present invention;

[0037] Figure 6 A schematic diagram of the vibration mode of the vibrating body of the land ultrasonic actuator provided in Example 1 of the present invention;

[0038] Figure 7 A closed-loop control flow chart of the robot's motion direction and thrust provided in Example 1 of the present invention;

[0039] Figure 8 A flow chart of the robot control strategy provided by Example 1 of the present invention;

[0040] Among them, 1. underwater ultrasonic actuator; 11. third vibrating body; 12. vibration-damping rubber ring; 13. second shell; 14. sealing cover; 2. onshore ultrasonic actuator; 21. first vibrating body; 22. first piezoelectric ceramic sheet; 23. fixing rod; 24. second vibrating body; 25. second piezoelectric ceramic sheet; 26. fixing cover; 27. magnetic contact; 28. first shell; 3. battery pack; 4. drive control circuit; 41. drive circuit board; 42. main control circuit board; 5. cabin; 6. magnetic cabin cover. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0043] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "include" and "comprise" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0045] Example 1

[0046] This embodiment provides an ultrasonic direct-driven amphibious mobile robot. Figure 1 As shown, it includes: a cabin 5, a drive control circuit 4 arranged in the cabin 5, an underwater ultrasonic actuator 1 arranged at the rear end of the cabin 5, and an onshore ultrasonic actuator 2 arranged at the bottom end of the cabin 5, and the underwater ultrasonic actuator 1 and the onshore ultrasonic actuator 2 are both electrically connected to the drive control circuit 4;

[0047] The land ultrasonic actuator 2 includes a first shell 28, and a first vibrating body 21 and a second vibrating body 24 arranged on both sides of the first shell 28, and the first vibrating body 21 and the second vibrating body 24 are respectively provided with a first piezoelectric ceramic sheet 22 and a second piezoelectric ceramic sheet 25, and the first piezoelectric ceramic sheet 22 and the second piezoelectric ceramic sheet 25 are both electrically connected to the driving control circuit 4;

[0048] The underwater ultrasonic actuator 1 comprises a second housing 13 and a third vibrating body 11 disposed in the second housing 13;

[0049] The driving control circuit 4 is used to apply a driving voltage to the third vibrating body 11 to excite the third vibrating body 11 to vibrate in the first-order tensile mode in the thickness direction, and generate ultrasonic waves of the same frequency in the water, and the ultrasonic waves and water generate thrust due to interaction, thereby driving the amphibious mobile robot to move underwater;

[0050] The drive control circuit 4 is used to apply a driving voltage to the first piezoelectric ceramic plate 22 and the second piezoelectric ceramic plate 25 to respectively excite the first vibrator 21 and the second vibrator 24 to vibrate in the first-order bending mode, thereby driving the amphibious mobile robot to move on land.

[0051] In this embodiment, an underwater ultrasonic actuator 1 is provided on both sides of the rear end of the cabin 5 to provide thrust for the amphibious mobile robot to move underwater. The amplitude of the driving voltage applied to the third vibrating body 11 of the two underwater ultrasonic actuators 1 is adjusted by the drive control circuit 4, thereby controlling acceleration, deceleration, differential turning and other actions.

[0052] Specifically, the amplitude of the driving voltage applied to the underwater ultrasonic actuator is controlled by the operational amplifier. The greater the driving voltage, the greater the thrust provided by the underwater ultrasonic actuator. By providing driving voltages of different sizes to the underwater ultrasonic actuators on the left and right sides, acceleration, deceleration, differential turning and other actions are achieved in a differential manner. At the same time, an acceleration sensor is used to perform closed-loop control of the movement direction and the thrust generated by the underwater ultrasonic actuator, thereby achieving precise movement of the robot.

[0053] A land ultrasonic actuator 2 is provided at the bottom end of the cabin 5 to provide thrust for the amphibious mobile robot to move on land.

[0054] The underwater ultrasonic actuator 1 and the onshore ultrasonic actuator 2 are both connected to the cabin 5 via screws, and are electrically connected to the drive control circuit 4 via waterproof cables and magnetic contacts.

[0055] The drive control circuit 4 includes a drive circuit board 41 and a main control circuit board 42; wherein the drive circuit board is a high-voltage drive board. The drive control circuit 4 uses a double circuit board for the following purposes: 1) isolating high-voltage signals from low-voltage signals to avoid interference; 2) due to the limited internal space of the robot, the double-board arrangement reduces the area of ​​a single circuit board and increases the height, thereby meeting the design requirements of a small overall size and easy integration of the robot.

[0056] The cabin body 5 and the magnetic cabin cover 6 form a closed space, and a battery pack 3 is also provided in the cabin body 5 for outputting a set power supply; the battery pack 3 is connected to a drive control circuit 4, and the drive control circuit 4 converts the output of the power supply into a driving voltage of a set magnitude and frequency, and applies it to the third vibrating body 11 of the underwater ultrasonic actuator 1, and the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet of the land ultrasonic actuator 2, so as to excite the vibrating bodies of the underwater ultrasonic actuator 1 and the land ultrasonic actuator 2, thereby controlling the vibration mode of the vibrating body.

[0057] In this embodiment, if Figure 2 As shown, the underwater ultrasonic actuator 1 includes: a second shell 13, a sealing cover 14, and a third vibrating body 11 arranged in the internal space formed by the second shell 13 and the sealing cover 14, the third vibrating body 11 is electrically connected to the drive control circuit 4, and a vibration-damping rubber ring 12 is provided on the third vibrating body 11; wherein the third vibrating body 11 is also a piezoelectric ceramic piece, and the piezoelectric ceramic piece serves as both an excitation source and a vibrating body, and what is excited is the first-order tensile mode of the piezoelectric ceramic piece itself in the thickness direction.

[0058] In addition to propellers, the current driving methods of amphibious mobile robots also include some new driving methods, such as the traveling wave drive of the flexible undulating fin designed in patent document CN113771566A, the jet drive generated by a piezoelectric pump driven by piezoelectric ceramics proposed in patent document CN113772053B, and the water surface thrust generated by vibration and fluid-solid coupling scheme for driving.

[0059] The amphibious mobile robot of this embodiment is also driven by piezoelectric ceramics, but the difference is that this embodiment uses piezoelectric ceramics to generate high-frequency ultrasonic waves in the MHz frequency band in water, and the ultrasonic waves in this frequency band are coupled with water to generate thrust.

[0060] In this embodiment, the third vibrator 11 is a cylindrical piezoelectric ceramic, which works in the first-order tensile mode in the thickness direction and has an operating frequency of 1.65 MHz. Figure 3 When the same frequency excitation voltage is applied to it, the piezoelectric ceramic can be stimulated to produce the modal vibration, and at the same time, ultrasonic waves of the same frequency are generated in the water. In this frequency band, the ultrasonic wave has good directivity and a strong force on the water, and can generate a large thrust.

[0061] As an optional implementation, the third vibrating body 11 may also be made of curved piezoelectric ceramics to concentrate ultrasonic energy.

[0062] like Figure 4 As shown, this embodiment carries out the acoustic-fluid coupling simulation of ultrasonic waves in water in this frequency band. The left figure is the sound pressure level image, in which it can be seen that the central sound pressure is significantly higher than the sound pressure on both sides, and the sound wave directivity is strong; the right figure is the fluid streamline image, which shows that the sound waves in this frequency band can produce a strong thrust on the water, generate a higher speed water flow at the rear, and generate two vortices at the same time.

[0063] In this embodiment, if Figure 5 As shown, the land 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 contact 27 and a first shell 28 .

[0064] Among them, the bottom of the first shell 28 is open, and the foot of the vibrator directly contacts the ground to achieve driving. The first vibrator 21 and the second vibrator 24 are arranged on both sides of the first shell 28. The first vibrator 21 is provided with a first piezoelectric ceramic sheet 22, and the second vibrator 24 is provided with a second piezoelectric ceramic sheet 25. The first vibrator 21 and the second vibrator 24 are used to drive the movement of the left and right sides respectively.

[0065] Magnetic contacts 27 are provided on the first piezoelectric ceramic sheet 22 and the second piezoelectric ceramic sheet 25 . The first piezoelectric ceramic sheet 22 and the second piezoelectric ceramic sheet 25 are electrically connected to the driving control circuit 4 via the magnetic contacts 27 .

[0066] In order to ensure that the vibration of the first vibrating body 21 and the second vibrating body 24 is not transmitted to a shell 28, fixed rods 23 are fixed at two nodes of the first-order bending mode of the first vibrating body 21 and the second vibrating body 24. The fixed rod 23 at one node passes through the first vibrating body 21 and the second vibrating body 24, so as to ensure that the linear displacement of the fixed rod 23 is extremely small, but there is still a certain rotational displacement.

[0067] A groove with an open upper end for placing the fixing rod 23 is provided on the first shell 28, and forms a closed groove with a part of the fixing cover 26; after assembly, the fixing rod 23 and the first vibrating body 21 and the second vibrating body 24 are interference fit, and the first shell 28 and the fixing cover 26 are clearance fit, providing a rotation space for the fixing rod 23, greatly reducing the transmission of vibration of the vibrating body to the shell, and also ensuring the influence of external fixed boundary conditions on the first-order bending mode vibration frequency of the first vibrating body 21 and the second vibrating body 24.

[0068] In this embodiment, the onshore driving part also adopts an ultrasonic driving solution, and the driving frequency band is in the KHz range. The driving principle of the onshore ultrasonic actuator is different from that of the underwater ultrasonic actuator. The piezoelectric ceramic in the underwater ultrasonic actuator serves as both an excitation source and a vibrator, and what is excited is the first-order tensile mode in the thickness direction of the piezoelectric ceramic itself. In the onshore ultrasonic actuator, the piezoelectric ceramic sheet is relatively thin and is only used as an excitation source to excite the first-order bending mode of the first steel vibrator 21 and the second vibrator 24, with a frequency of 48.5KHz, as shown in FIG. Figure 6 In this mode, due to the directionality of the foot contacting the ground, the on-land ultrasonic actuator generates driving capability.

[0069] In this embodiment, the driving control circuit 4 controls the amplitude of the driving voltage of the vibrating bodies on the left and right sides of the land ultrasonic actuator, so that the land ultrasonic actuator can achieve acceleration, deceleration, differential steering and other movements.

[0070] Specifically: the amplitude of the driving voltage applied to the land ultrasonic actuator is controlled by the operational amplifier. The greater the driving voltage, the greater the thrust provided by the land ultrasonic actuator. Therefore, by providing driving voltages of different sizes to the vibrating bodies on the left and right sides, acceleration, deceleration, differential turning and other actions are achieved in a differential manner. At the same time, an acceleration sensor is used to perform closed-loop control of the movement direction and the thrust of the land ultrasonic actuator, thereby achieving precise movement of the robot.

[0071] In this embodiment, the closed-loop control process of the robot's motion direction and thrust is as follows: Figure 7 As shown in the figure, specifically: set the target angle and target thrust; collect the current output angle and output thrust through the acceleration sensor and feedback the angle and linear acceleration; obtain the error angle according to the target angle and the feedback angle, use the direction PID controller to solve the acceleration according to the error angle, and obtain the error acceleration according to the feedback acceleration, and then feedback control the thrust generated by the actuator through the thrust PID controller, and realize the precise control of the motion direction and thrust through the cascade PID control algorithm of direction and thrust.

[0072] In this embodiment, the drive control circuit integrates the wireless communication module of the robot, and receives the control instructions issued by the remote control handle through the wireless communication module. Figure 8 As shown, after receiving the instruction, the instruction is judged and different working modes are entered, and the working modes include automatic mode, surface mode and land mode. In different modes, the water level sensor detects whether it is in water. If it is in water, the underwater ultrasonic actuator is started, otherwise the land ultrasonic actuator is started; among them, if in the surface mode, the water level sensor detects that the robot is not in water, and then a non-surface error instruction is returned; if in the land mode, the water level sensor detects that the robot is in water, and then a non-land error instruction is returned.

[0073] It is understandable that the size and shape of the vibrating body and the number of piezoelectric ceramics in the land-based ultrasonic actuator may also be changed, and other modes may be applied according to actual conditions.

[0074] This embodiment proposes an amphibious mobile robot driven by ultrasonic direct drive, which uses ultrasonic transducers to directly interact with both water and land media to make a 117.78×105.24×56.79mm 3 The small prototype weighs 234.36g and uses wireless communication to achieve movement in both water and land, and has the ability to move underwater without noise or traces. The prototype can achieve a maximum speed of 154.66mm / s on the ground and 54.64mm / s on the water; the maximum load on the bottom is 1357.66g, which is 5.79 times its own weight. In addition, thanks to the special advantages of ultrasonic transducer drive, ground operation can achieve a minimum step distance of 6.5um, and can complete high-precision adjustment of posture and viewing angle in special reconnaissance environments.

[0075] Example 2

[0076] This embodiment provides an actuation method for the ultrasonic direct-drive amphibious mobile robot described in Embodiment 1, comprising:

[0077] When traveling underwater, a driving voltage is applied to the third vibrator pair of the underwater ultrasonic actuator to excite the third vibrator to vibrate in the first-order tensile mode in the thickness direction, and ultrasonic waves of the same frequency are generated in the water. The ultrasonic waves interact with the water to generate thrust, thereby driving the amphibious mobile robot to travel underwater;

[0078] When traveling on land, a driving voltage is applied to the first piezoelectric ceramic piece and the second piezoelectric ceramic piece of the land ultrasonic actuator to respectively excite the first vibrator and the second vibrator to vibrate in the first-order bending mode, thereby driving the amphibious mobile robot to travel on land.

[0079] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. An amphibious mobile robot driven by ultrasonic direct drive. It is characterized in that include: A cabin, a drive control circuit disposed in the cabin, an underwater ultrasonic actuator disposed at the rear end of the cabin, and an onshore ultrasonic actuator disposed at the bottom end of the cabin, wherein both the underwater ultrasonic actuator and the onshore ultrasonic actuator are electrically connected to the drive control circuit; The land ultrasonic actuator comprises a first shell, and a first vibrating body and a second vibrating body arranged on both sides of the first shell, the first vibrating body and the second vibrating body are respectively provided with a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet, and the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are both electrically connected to the drive control circuit; The underwater ultrasonic actuator comprises a second shell and a third vibrating body arranged in the second shell; The drive control circuit is used to apply a driving voltage to the third vibrator to excite the third vibrator to vibrate in a first-order tensile mode in the thickness direction, and generate ultrasonic waves of the same frequency in water, and the ultrasonic waves and water generate thrust due to interaction, thereby driving the amphibious mobile robot to move underwater; The drive control circuit is used to apply a driving voltage to the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet to respectively excite the first vibrator and the second vibrator to vibrate in the first-order bending mode, thereby driving the amphibious mobile robot to move on land.

2. The ultrasonic direct-driven amphibious mobile robot according to claim 1, It is characterized in that Underwater ultrasonic actuators are provided on both sides of the rear end of the cabin, and different driving voltages are applied to the third vibrating bodies of the two underwater ultrasonic actuators through the drive control circuit, and different driving voltages are applied to the first vibrating body and the second vibrating body through the drive control circuit, so as to control the acceleration, deceleration and differential turning movements underwater or on land in a differential manner.

3. The ultrasonic direct-driven amphibious mobile robot according to claim 2, It is characterized in that The motion direction of the amphibious mobile robot and the thrust of the underwater ultrasonic actuator and the onshore ultrasonic actuator are controlled in a closed loop; specifically, the control includes: setting a target motion direction angle and a target thrust, collecting the current motion direction angle and the actuator thrust, and feeding back the current motion direction angle and acceleration; obtaining an error angle according to the target motion direction angle and the current motion direction angle, using a directional PID controller to resolve the acceleration according to the error angle, and obtaining an error acceleration according to the feedback acceleration, and then feedback-controlling the thrust generated by the underwater ultrasonic actuator and the onshore ultrasonic actuator through a thrust PID controller.

4. The ultrasonic direct-driven amphibious mobile robot according to claim 1, It is characterized in that The cabin is also provided with a battery pack for outputting power supply, and the battery pack is connected to a drive control circuit, which is used to convert the output of the power supply into a driving voltage and apply it to the third vibrating body or the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet.

5. The ultrasonic direct-driven amphibious mobile robot according to claim 1, It is characterized in that A magnetic contact is provided on the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet, and the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are electrically connected to the drive control circuit through the magnetic contact; The third vibrating body is electrically connected to the driving control circuit via a magnetic contact, and a vibration-damping rubber ring is provided on the third vibrating body; The third vibrator is a piezoelectric ceramic, which serves as both an excitation source and a vibrator.

6. The ultrasonic direct-driven amphibious mobile robot according to claim 5, It is characterized in that The third vibrating body is a cylindrical sheet piezoelectric ceramic or a curved surface piezoelectric ceramic.

7. The ultrasonic direct-driven amphibious mobile robot according to claim 1, It is characterized in that The driving frequency band of the underwater ultrasonic actuator is a MHz frequency band; The driving frequency band of the onshore ultrasonic actuator is a KHz frequency band.

8. The ultrasonic direct-driven amphibious mobile robot according to claim 1, It is characterized in that The land ultrasonic actuator also includes a fixing cover, a fixing rod is provided at two nodes of the first-order bending mode of the first vibrating body and the second vibrating body, a groove open for placing the upper end of the fixing rod is provided on the first shell, and forms a closed groove with the fixing cover, an interference fit is formed between the fixing rod and the first vibrating body and the second vibrating body, and a clearance fit is formed between the fixing rod and the first shell and the fixing cover.

9. The ultrasonic direct-driven amphibious mobile robot according to claim 1, It is characterized in that The drive control circuit is also used to receive control instructions and select to enter different working modes according to the control instructions, and the working modes include automatic mode, surface mode and land mode; in different modes, the water level sensor detects whether the amphibious mobile robot is in water, and if it is in water, the underwater ultrasonic actuator is started, otherwise the land ultrasonic actuator is started; wherein, if in the surface mode, the water level sensor detects that the amphibious mobile robot is not in water, and then a non-surface error instruction is returned; if in the land mode, the water level sensor detects that the amphibious mobile robot is in water, and then a non-land error instruction is returned.

10. An actuation method for an ultrasonic direct-drive amphibious mobile robot according to any one of claims 1 to 9, It is characterized in that include: When traveling underwater, a driving voltage is applied to the third vibrator of the underwater ultrasonic actuator to excite the third vibrator to vibrate in the first-order tensile mode in the thickness direction, and ultrasonic waves of the same frequency are generated in the water. The ultrasonic waves interact with the water to generate thrust, thereby driving the amphibious mobile robot to travel underwater. When traveling on land, a driving voltage is applied to the first piezoelectric ceramic piece and the second piezoelectric ceramic piece of the land ultrasonic actuator to respectively excite the first vibrator and the second vibrator to vibrate in the first-order bending mode, thereby driving the amphibious mobile robot to travel on land.

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