Underwater robot based on sandwich type piezoelectric transducer and working method thereof

Abstract

The invention discloses a novel underwater robot based on a sandwich type piezoelectric transducer, and relates to the field of piezoelectric driving. The device comprises a sandwich type piezoelectric transducer, a clamping structure, a base body, two tension springs, four bearings, a first axle, a second axle and four wheels. The sandwich type piezoelectric transducer is fixed between two vertical plates of the base body through a clamping structure, two wheel shafts of the wheel are clamped in wheel shaft holes of the base body through bearings and limiting gaskets, and two tension springs are hung on bolts on the two sides of the base body and are in a stretching state, so that two plane driving feet at the bottom of the piezoelectric transducer abut against the two wheel shafts. When the robot works, the sandwich type piezoelectric transducer is excited, the two plane driving feet at the bottom of the sandwich type piezoelectric transducer generate elliptical motion in the same direction, the two wheel shafts are driven to rotate through friction, then the wheels are driven to rotate, and movement of the robot is achieved. According to the technical scheme, the problems that an existing underwater robot is large in size, complex in structure and difficult in dynamic sealing in the high-water-pressure environment are solved.

Description

Technical Field

[0001] This invention relates to the fields of piezoelectric actuators and underwater robots, and more particularly to a novel underwater robot with a sandwich-type piezoelectric transducer. Background Technology

[0002] Underwater robots are indispensable tools for seabed exploration, and are mostly wheeled or propeller-driven. They are characterized by their small size, fast response, and simple sealing, playing a vital role in underwater monitoring and deep-sea resource exploration.

[0003] The deep-sea environment presents the challenge of high water pressure; for every 1000 meters increase in depth, the pressure increases by 1 MPa. This high-pressure environment hinders the development of deep-sea exploration. If traditional electromagnetic motors are used for propulsion, the drive components must be sealed with a heavy, pressure-resistant shell to prevent damage and failure under high pressure. Furthermore, the complex transmission structure restricts the miniaturization and high-pressure resistance of underwater robots.

[0004] Piezoelectric actuators generate micron-level elliptical motion on the surface particles of the stator actuator head, and transmit motion between the stator and actuator through friction. Because piezoelectric actuators can operate in aquatic environments after only simple sealing of the stator structure, and can withstand high water pressure environments of 110MPa; direct drive eliminates the need for a transmission mechanism, which is beneficial for high pressure resistance, lightweight design, and miniaturization. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies mentioned in the background art by providing a novel underwater robot based on a sandwich piezoelectric transducer.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution;

[0007] A novel underwater robot based on a sandwich piezoelectric transducer includes a sandwich piezoelectric transducer, a clamping structure, a base, two tension springs, four bearings, a first axle, a second axle, and four wheels.

[0008] The sandwich piezoelectric transducer includes a rear end cover, a flange, and two front end covers;

[0009] The rear end cover consists of two cubes connected by a central convex beam. The upper surface of the cubes has a groove through-hole that leads directly to the lower surface.

[0010] The flange has a symmetrical structure on both sides and a raised middle section. The upper and lower planes of the symmetrical parts on both sides have through holes for connecting the rear end cover and the front end cover. The front and rear end faces of the raised middle section have through holes for clamping the sandwich piezoelectric transducer between the clamping structures.

[0011] The front cover is a variable cross-section device, with the bottom end of the lower variable cross-section being a driving foot plane, the upper part being a cuboid with a constant cross-section, and a groove hole for connecting the rear cover being opened on the top surface.

[0012] Two piezoelectric ceramic plates with square circular holes for generating longitudinal vibration are sandwiched between the lower end face of the rear end cover and the upper surface of the flange, as well as between the lower surface of the flange and the top surface of the front end cover. The piezoelectric ceramic plates are placed at the node of the Nth order longitudinal vibration of the sandwich piezoelectric transducer, where N is an odd number and is the longitudinal vibration order of the pre-set working mode.

[0013] The piezoelectric ceramic sheets used to generate longitudinal vibration are all polarized along their thickness direction;

[0014] The bottom of the clamping structure is a cuboid boss. On the cuboid boss, there are two upright plates for clamping the piezoelectric transducer flange. The two upright plates have through holes that are aligned with the through holes on the front and rear end faces of the piezoelectric transducer flange. The left and right sides of the cuboid boss at the bottom of the clamping structure are locked between the two driving feet of the piezoelectric transducer.

[0015] The bottom of the base is a cuboid groove. The left and right side plates of the groove have two concentric through holes for placing bearings and several bolt holes for placing bolts to facilitate suspension of the tension spring. Several through holes are opened at the bottom for limiting the propulsion device. There is a vertical plate on each of the left and right side plates of the base. The two vertical plates have waist-shaped holes for limiting the clamping structure.

[0016] The two tension springs are placed symmetrically on the outside of the two vertical plates of the base. One end of the tension spring is suspended on the bolt that passes through the waist hole on the two vertical plates of the base, and the other end is suspended on the bolt that is fixed to the bolt hole on the left and right side plates of the bottom groove of the base.

[0017] The four bearings are respectively installed in the bearing holes on the cuboid groove wall at the bottom of the base. The left and right bearings are placed concentrically, and the inner holes of the front and rear bearings are used to place the first wheel axle and the second wheel axle, respectively.

[0018] The first and second axles are respectively installed through the front and rear bearing holes. The outer edge of the axle is tangent to the driving foot plane at the bottom of the sandwich piezoelectric transducer. At the same time, pin holes for placing pins are provided on the outer side of the left and right bearing holes on the axle to limit the axle. Meanwhile, the two ends of the axle are stepped for connecting to the inner hub of the wheel. Bolt holes are opened on both end faces of the axle for installing bolts to limit the wheel along the axle axis.

[0019] The four wheels have identical structures. Each wheel includes an inner hub, an outer hub, an axle, and several spokes. The inner and outer hubs are concentrically arranged, with the inner hub having a waist-shaped hole and the outer hub having an annular shape. The spokes are evenly installed between the inner and outer hubs, with one end of each spoke fixed to the inner hub and the other end fixed to the outer hub. The axle is connected to the inner hub, and the wheels are fixed relative to the axle.

[0020] As a further optimization of the sandwich-type piezoelectric driven underwater mobile robot of the present invention, the four wheels, axles and inner hubs are rotatably connected by an interference fit.

[0021] As a further optimization of the sandwich-type piezoelectric driven underwater mobile robot of the present invention, the wheel axle and the base body are fitted together by bearings.

[0022] As a further optimization of the sandwich-type piezoelectric driven underwater mobile robot of the present invention, the four wheels are completely identical in shape and size.

[0023] As a further optimization of the sandwich-type piezoelectric-driven underwater mobile robot of the present invention, the two front end covers are completely identical in shape and size.

[0024] As a further optimization of the sandwich-type piezoelectric-driven underwater mobile robot of the present invention, the two vertical plates of the base are symmetrically arranged with equally spaced threaded holes for mating with bolts.

[0025] As a further optimization of the sandwich-type piezoelectric-driven underwater mobile robot of the present invention, one end of the tension spring is suspended on a bolt passing through the center hole of the flange, and the other end is suspended on bolts on the two vertical plates of the base.

[0026] As a further optimization of the sandwich-type piezoelectric driven underwater mobile robot of the present invention, the bearing is made of zirconia ceramic material.

[0027] The present invention also discloses a method for operating the patch-type piezoelectric driven mobile robot, comprising the following steps:

[0028] A first signal is applied to one side of the piezoelectric ceramic sheet of the sandwich piezoelectric transducer, and a second signal is applied to the other side. The first signal and the second signal are π / 2 out of time, causing the sandwich piezoelectric transducer to generate N-order longitudinal vibration and N+1-order bending vibration with a π / 2 phase difference in time. This, in turn, causes the driving feet at the bottom of the two front end caps to generate clockwise micro-elliptical motions with the same direction. The two driving feet then drive two axles to rotate in the same direction through friction, and the axles then drive the wheels to rotate in the same direction.

[0029] By changing the phase difference between the first and second signals in time to -π / 2, the particles on the plane of the two front end caps are driven to make a counterclockwise micro-elliptical motion, thereby changing the direction of rotation of the axle and the wheel.

[0030] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0031] 1. It adopts a sandwich-type piezoelectric drive, which has a greater driving force, higher output efficiency of dual-drive feet, and greater robot movement speed.

[0032] 2. The robot is open in design and does not require sealing, thus avoiding the problem of seal leakage under high water pressure.

[0033] 3. The drive foot plane contacts the wheel axle curved surface, avoiding the phenomenon of the drive foot and wheel axle getting stuck.

[0034] 4. Direct drive eliminates the need for a transmission mechanism, which is beneficial for lightweighting and miniaturization. Attached Figure Description

[0035] Figure 1 This is a structural schematic diagram of a novel underwater robot based on a sandwich-type piezoelectric transducer according to the present invention;

[0036] Figure 2 This is a schematic diagram of the piezoelectric ceramic sheet applying an electrical signal in the sandwich piezoelectric transducer of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the substrate of the present invention;

[0038] Figure 4 This is a schematic diagram of the clamping structure of the present invention;

[0039] Figure 5 This is a schematic diagram of the axle structure of the present invention;

[0040] Figure 6 This is a schematic diagram of the structure of the wheel of the present invention;

[0041] Figure 7 This is a schematic diagram of the sandwich piezoelectric transducer in this invention, showing how the bottom ends of the two front end caps drive the surface particles to generate elliptical motion.

[0042] In the diagram, 1-sandwich piezoelectric transducer, 1.1-rear end cover, 1.2-flange, 1.3-front end cover, 1.4-piezoelectric ceramic sheet, 2-substrate, 2.1-waist-shaped hole, 2.2-bearing hole, 2.3-bolt hole, 3-bolt, 4-clamping structure, 4.1-flange positioning hole, 4.2-clamping structure boss, 5-tension spring, 6-pin, 7-first axle, 7.1-pin hole, 7.2-counterside bolt hole, 7.3-limiting surface, 8-wheel, 8.1-outer hub of the wheel, 8.2-inner hub of the wheel, 8.3-wheel spoke, 9-limiting gasket, 10-second axle, 11-bearing. Detailed Implementation

[0043] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings: This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0044] like Figure 1 As shown, the present invention discloses a novel underwater robot based on a sandwich piezoelectric transducer, comprising a sandwich piezoelectric transducer, a clamping structure, a base, two tension springs, four bearings, a first axle, a second axle, and four wheels.

[0045] like Figure 2 As shown, the sandwich piezoelectric transducer includes a rear end cover, a piezoelectric ceramic plate, a flange, and two front end covers.

[0046] The rear end cover consists of two cubes connected by a central convex beam. The upper surface of each cube has a groove through which a hole leads to the lower surface.

[0047] The flange has a symmetrical structure on both sides and a raised middle section. The upper and lower planes of the symmetrical parts on both sides have through holes for connecting the rear end cover and the front end cover. The front and rear end faces of the raised middle section have through holes for clamping the sandwich piezoelectric transducer between the clamping structures.

[0048] The front cover is a variable cross-section device. The bottom of the variable cross-section is the driving foot plane, the upper part is a cuboid with a constant cross-section, and the top surface has a groove hole for connecting the rear cover.

[0049] Two piezoelectric ceramic plates with square circular holes for generating longitudinal vibration are sandwiched between the lower end face of the rear cover and the upper surface of the flange, as well as between the lower surface of the flange and the top surface of the front cover. The piezoelectric ceramic plates are placed at the node of the Nth order longitudinal vibration of the sandwich piezoelectric transducer, where N is an odd number and is the longitudinal vibration order of the pre-set working mode.

[0050] The piezoelectric ceramic sheets used to generate longitudinal vibrations are all polarized along their thickness direction.

[0051] like Figure 3 As shown, the bottom of the clamping structure is a cuboid boss. On the cuboid boss, there are two upright plates for clamping the piezoelectric transducer flange. The two upright plates have through holes that are aligned with the through holes on the front and rear end faces of the piezoelectric transducer flange. The left and right sides of the cuboid boss at the bottom of the clamping structure are locked between the two driving feet of the piezoelectric transducer to prevent the sandwich piezoelectric transducer from rotating during operation.

[0052] like Figure 4 As shown, the bottom of the base is a cuboid groove. The left and right side plates of the groove have concentric through holes for placing bearings and several bolt holes for placing bolts to facilitate suspension of the tension spring. The bottom has several through holes for limiting the propulsion device. There is a vertical plate on each of the left and right side plates of the base. The two vertical plates have waist-shaped holes for limiting the clamping structure.

[0053] Two tension springs are placed symmetrically on the outside of the two vertical plates of the base. One end of the tension spring is suspended on the bolt that passes through the waist hole on the two vertical plates of the base, and the other end is suspended on the bolt that is fixed to the bolt hole on the left and right side plates of the bottom groove of the base.

[0054] Four bearings are respectively installed in the bearing holes on the rectangular groove wall at the bottom of the base. The left and right bearings are placed concentrically, and the inner holes of the front and rear bearings are used to place the first wheel axle and the second wheel axle, respectively.

[0055] like Figure 5 As shown, the first and second wheel axles are respectively installed through the front and rear bearing holes. The outer edge of the wheel axle is tangent to the driving foot plane at the bottom of the sandwich piezoelectric transducer. At the same time, pin holes for placing pins are provided on the outer side of the left and right bearing holes on the wheel axle to limit the wheel axle. Meanwhile, the two ends of the wheel axle are stepped to connect with the inner hub of the wheel. Bolt holes are opened on both ends of the wheel axle to install bolts to limit the wheel along the wheel axle axis.

[0056] like Figure 6 As shown, the four wheels have identical structures. Each wheel includes an inner hub, an outer hub, an axle, and several spokes. The inner and outer hubs are concentrically arranged, with the inner hub having a waist-shaped hole and the outer hub having an annular shape. The spokes are evenly installed between the inner and outer hubs, with one end of each spoke fixed to the inner hub and the other end fixed to the outer hub. The axle is connected to the inner hub, and the wheels are fixed relative to the axle.

[0057] The four wheels are identical in shape and size, and the wheel axles and inner hubs are connected by an interference fit.

[0058] The axle and the base are fitted together by bearings.

[0059] The two front caps are exactly the same in shape and size.

[0060] The two vertical plates of the base are symmetrically arranged with equally spaced threaded holes for bolt engagement, which facilitates the adjustment of the extension of the tension spring.

[0061] One end of the tension spring is suspended on a bolt passing through the center hole of the flange, and the other end is suspended on bolts on the two vertical plates of the base.

[0062] The bearings are made of zirconia ceramic material to prevent them from rusting underwater and affecting the rotation of the wheel axle.

[0063] The present invention also discloses a method for operating the patch-type piezoelectric driven mobile robot, comprising the following steps:

[0064] like Figure 7 As shown, a first signal is applied to the piezoelectric ceramic sheet on one side of the sandwich piezoelectric transducer, and a second signal is applied to the piezoelectric ceramic sheet on the other side. The first signal and the second signal are π / 2 out of time, causing the sandwich piezoelectric transducer to generate N-order longitudinal vibration and N+1-order bending vibration with a π / 2 phase difference in time. This, in turn, causes the driving feet at the bottom of the two front end caps to generate clockwise micro-elliptical motions with the same direction. The two driving feet then drive the two axles to rotate in the same direction through friction, and the axles then drive the wheels to rotate in the same direction.

[0065] By changing the phase difference between the first and second signals in time to -π / 2, the particles on the plane of the two front end caps are driven to make a counterclockwise micro-elliptical motion, thereby changing the direction of rotation of the axle and the wheel.

[0066] It will be understood by those skilled in the art 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 invention 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.

[0067] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A novel underwater robot based on a sandwich piezoelectric transducer, characterized in that, It includes a sandwich piezoelectric transducer, a clamping structure, a base, two tension springs, four bearings, a first axle, a second axle, and four wheels; The sandwich piezoelectric transducer includes a rear end cover, a flange, and two front end covers; The rear end cover consists of two cubes connected by a central convex beam. The upper surface of the cubes has a groove through-hole that leads directly to the lower surface. The flange has a symmetrical structure on both sides and a raised middle section. The upper and lower planes of the symmetrical parts on both sides have through holes for connecting the rear end cover and the front end cover. The front and rear end faces of the raised middle section have through holes for clamping the sandwich piezoelectric transducer between the clamping structures. The front cover is a variable cross-section device, with the bottom end of the lower variable cross-section being a driving foot plane, the upper part being a cuboid with a constant cross-section, and a groove hole for connecting the rear cover being opened on the top surface. Two piezoelectric ceramic plates with square circular holes for generating longitudinal vibration are sandwiched between the lower end face of the rear end cover and the upper surface of the flange, as well as between the lower surface of the flange and the top surface of the front end cover. The piezoelectric ceramic plates are placed at the node of the Nth order longitudinal vibration of the sandwich piezoelectric transducer, where N is an odd number and is the longitudinal vibration order of the pre-set working mode. The piezoelectric ceramic sheets used to generate longitudinal vibration are all polarized along their thickness direction; The bottom of the clamping structure is a cuboid boss. On the cuboid boss, there are two upright plates for clamping the piezoelectric transducer flange. The two upright plates have through holes that are aligned with the through holes on the front and rear end faces of the piezoelectric transducer flange. The left and right sides of the cuboid boss at the bottom of the clamping structure are locked between the two driving feet of the piezoelectric transducer. The bottom of the base is a cuboid groove. The left and right side plates of the groove have two concentric through holes for placing bearings and several bolt holes for placing bolts to facilitate suspension of the tension spring. Several through holes are opened at the bottom for limiting the propulsion device. There is a vertical plate on each of the left and right side plates of the base. The two vertical plates have waist-shaped holes for limiting the clamping structure. The two tension springs are placed symmetrically on the outside of the two vertical plates of the base. One end of the tension spring is suspended on the bolt that passes through the waist hole on the two vertical plates of the base, and the other end is suspended on the bolt that is fixed to the bolt hole on the left and right side plates of the bottom groove of the base. The four bearings are respectively installed in the bearing holes on the cuboid groove wall at the bottom of the base. The left and right bearings are placed concentrically, and the inner holes of the front and rear bearings are used to place the first wheel axle and the second wheel axle, respectively. The first and second axles are respectively installed through the front and rear bearing holes. The outer edge of the axle is tangent to the driving foot plane at the bottom of the sandwich piezoelectric transducer. At the same time, pin holes for placing pins are provided on the outer side of the left and right bearing holes on the axle to limit the axle. Meanwhile, the two ends of the axle are stepped for connecting to the inner hub of the wheel. Bolt holes are opened on both end faces of the axle for installing bolts to limit the wheel along the axle axis. The four wheels have identical structures. Each wheel includes an inner hub, an outer hub, an axle, and several spokes. The inner and outer hubs are concentrically arranged, with the inner hub having a waist-shaped hole and the outer hub having an annular shape. The spokes are evenly installed between the inner and outer hubs, with one end of each spoke fixed to the inner hub and the other end fixed to the outer hub. The axle is connected to the inner hub, and the wheels are fixed relative to the axle.

2. The sandwich-type piezoelectric transducer underwater robot according to claim 1, characterized in that, The four wheels are rotatably connected by an interference fit between the axle and the inner hub.

3. The sandwich-type piezoelectric transducer underwater robot according to claim 1, characterized in that, The axle and the base are fitted together by bearings.

4. The sandwich-type piezoelectric transducer underwater robot according to claim 1, characterized in that, The four wheels are identical in shape and size.

5. The sandwich-type piezoelectric transducer underwater robot according to claim 1, characterized in that, The two front caps are exactly the same in shape and size.

6. The sandwich-type piezoelectric transducer underwater robot according to claim 1, characterized in that, The two vertical plates of the base have symmetrically arranged threaded holes at equal intervals for use with bolts.

7. The sandwich-type piezoelectric transducer underwater robot according to claim 1 or 6, characterized in that, One end of the tension spring is suspended on a bolt passing through the center hole of the flange, and the other end is suspended on bolts on the two vertical plates of the base.

8. The sandwich-type piezoelectric transducer underwater robot according to claim 1, characterized in that, The bearing is made of zirconia ceramic material.

9. The working method of the underwater robot based on the sandwich piezoelectric transducer according to claim 1, characterized in that, Includes the following processes: A first signal is applied to the piezoelectric ceramic sheet on one side of the sandwich piezoelectric transducer, and a second signal is applied to the piezoelectric ceramic sheet on the other side. The first signal and the second signal are π / 2 out of phase in time, which causes the sandwich piezoelectric transducer to generate Nth-order longitudinal vibration and N+1th-order bending vibration with a phase difference of π / 2 in time. This, in turn, causes the driving foot planes at the bottom of the two front end covers to generate clockwise micro-elliptical motions with the same direction. The two driving feet drive the two axles to rotate in the same direction through friction, and then the axles drive the wheels to rotate in the same direction. By changing the phase difference between the first and second signals in time to -π / 2, the particles on the plane of the two front end caps are driven to make a counterclockwise micro-elliptical motion, thereby changing the direction of rotation of the axle and the wheel.

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