A sandwich type longitudinal bending composite piezoelectric driven crawler device and its use method

Abstract

The present invention discloses a sandwich-type longitudinal-bending composite piezoelectric driven crawler device and a method for using the same, including a longitudinal-bending composite piezoelectric driver, a driver fixing base and a set of crawlers, wherein the piezoelectric driver includes a bending vibration piezoelectric ceramic group, a longitudinal vibration piezoelectric ceramic group, a driving ring, an amplitude rod, a double-headed stud and a rear end cover, and the piezoelectric driver is arranged in rotational symmetry, and the driver fixing base can adjust the position of the piezoelectric driver along the axial direction, thereby adjusting the tension of the crawler. The method for using the device includes the following steps: 1. Assembling and adjusting the longitudinal-bending composite piezoelectric driver; 2. The piezoelectric driver applies a sinusoidal excitation voltage with a two-phase phase difference of 90° to form a traveling wave on the ring and drives the crawler device to move through friction coupling. The present invention combines the advantages of a traditional crawler travel mechanism with the characteristics of compact structure and direct drive of a piezoelectric driver, and has the advantages of simple and compact structure, high speed, and high energy density.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric ultrasonic drivers, and in particular relates to a sandwich-type longitudinal-bending composite piezoelectric drive crawler device and a method of using the same. Background Art

[0002] In July 2020, my country's first Mars exploration mission, the Tianwen-1 probe, was successfully launched from the Wenchang Space Launch Center in China, officially starting the Chinese people's independent exploration of Mars. The demand for special robots in planetary exploration, disaster relief and exploration, and military explosion-proof reconnaissance is increasing. In order to meet the operational needs of unstructured terrain environments, various mobile robots with legs, wheels, tracks, and composite structures of the above forms have been developed and manufactured at home and abroad in recent years.

[0003] Tracked robots can adapt well to complex terrain and have excellent obstacle-crossing performance and adaptability. Their tracks have a large support area and a small ground contact pressure, making them suitable for operations in soft terrain or muddy sites.

[0004] Tracked robots can adapt well to complex terrains and have excellent obstacle-crossing performance and adaptability. Their tracks have a large support area and a low ground contact pressure, making them suitable for operations in soft terrain or muddy fields. However, the drive and travel systems of traditional tracked vehicles, such as sprockets, idlers, road wheels, transmission systems, and lubrication systems, result in the tracked devices being heavy, having a complex structure, having low mechanical integration, and having low drive efficiency. Piezoelectric actuators do not require a speed reduction system, thus avoiding a cumbersome transmission system; in addition, piezoelectric actuators do not require a lubrication system; therefore, tracked devices driven by piezoelectric actuators have potential application prospects in special fields such as planetary exploration. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a sandwich-type longitudinal-bending composite piezoelectric driven track device and a method of using the same in view of the deficiencies in the above-mentioned prior art. The device combines the advantages of a traditional track travel mechanism with the compact structure and direct drive characteristics of a piezoelectric drive, and has the advantages of a simple and compact structure, flexible and changeable design, fast speed, and high energy density.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A sandwich type longitudinal bending composite piezoelectric driven crawler device, comprising a driver mounting base, a metal crawler and three identical longitudinal bending composite piezoelectric drivers; wherein the driver mounting base is arranged on the inner side of the metal crawler, and the three longitudinal bending composite piezoelectric drivers are arranged in a rotationally symmetrical manner on the circumference of the driver mounting base and contact the inner side of the metal crawler;

[0008] One end of each longitudinal-bending composite piezoelectric actuator is installed on the rear end cover on the actuator mounting base, and the other end is a piezoelectric actuator ring that contacts the inner side of the metal track. The longitudinal-bending composite piezoelectric actuator can adjust the relative position of the metal track and the piezoelectric actuator ring through the relative position of the rear end cover and the mounting base, thereby changing the tension of the metal track.

[0009] A further improvement of the present invention is that the driver mounting base includes a fixed base and three movable bases which are arranged in a rotationally symmetrical manner along the circumference of the fixed base.

[0010] A further improvement of the present invention is that a T-shaped groove is provided on the fixed base for the rear end cover to move toward or away from the rotating metal track, and the movable base can be in the corresponding T-shaped groove.

[0011] A further improvement of the present invention is that each longitudinal-bending composite piezoelectric driver comprises a rear end cover, a piezoelectric driver ring, a longitudinal vibration piezoelectric ceramic group, a bending vibration piezoelectric ceramic group, a double-headed stud and an amplitude change rod integrated with the piezoelectric driver ring, a longitudinal vibration piezoelectric ceramic group and a bending vibration piezoelectric ceramic group are sandwiched between the amplitude change rod and the rear end cover, each piece of longitudinal vibration ceramic in the longitudinal vibration piezoelectric ceramic group is a whole piece of ceramic, and the polarization directions of two adjacent piezoelectric ceramics are opposite, and each piece of longitudinal vibration ceramic in the bending vibration piezoelectric ceramic group is a whole piece of ceramic, and the polarization directions of two adjacent piezoelectric ceramics are opposite.

[0012] A further improvement of the present invention is that each ceramic piece of the longitudinal vibration piezoelectric ceramic group and the bending vibration piezoelectric ceramic group is an annular ceramic, and the ceramic passes through the stud and is clamped between the rear end cover and the amplitude transformer by thread pre-tightening.

[0013] A method for using a sandwich-type longitudinal-bending composite piezoelectric driven crawler device, the method for using the sandwich-type longitudinal-bending composite piezoelectric driven crawler device comprising the following steps:

[0014] Step 1: Assembly and adjustment of sandwich-type longitudinal-bending composite piezoelectric actuator:

[0015] Step 101, the longitudinal vibration piezoelectric ceramic group is clamped between the amplitude transformer and the stud by threaded connection, the bending vibration piezoelectric ceramic group is clamped between the stud and the rear end cover by threaded connection, and each ceramic piece of the longitudinal vibration piezoelectric ceramic group and the bending vibration piezoelectric ceramic group is bonded by epoxy resin glue respectively;

[0016] Step 102, installing a movable base on the fixed base of the installation base, and installing a sandwich-type longitudinal-bending composite piezoelectric driver on the movable base;

[0017] Step 103, adjusting the position between the sandwich-type longitudinal-bending composite piezoelectric actuator and the actuator mounting base to adjust the preload force between the piezoelectric actuator ring and the contact surface of the metal track; wherein the three sandwich-type longitudinal-bending composite piezoelectric actuators are arranged in rotational symmetry, and the piezoelectric actuator ring is tangent to and in contact with the metal track;

[0018] Step 2: Apply two-phase sinusoidal excitation voltage and track movement to the sandwich type longitudinal bending composite piezoelectric drive track device:

[0019] Step 201, applying a sinusoidal excitation voltage to the longitudinal vibration piezoelectric ceramic group of the sandwich longitudinal bending composite piezoelectric actuator, the longitudinal vibration piezoelectric ceramic group expands and contracts along the axial direction of the sandwich longitudinal bending composite piezoelectric actuator, and the sandwich longitudinal bending composite piezoelectric actuator is stimulated to generate longitudinal vibration, thereby stimulating the ring to generate an in-plane bending vibration mode, and the contact position between the amplitude rod and the ring is the node position of the bending vibration mode of the ring;

[0020] Step 202, applying another sinusoidal excitation voltage with a phase difference of 90° to the bending vibration piezoelectric ceramic group of the sandwich-type longitudinal-bending composite piezoelectric actuator, so that the bending vibration piezoelectric ceramic group alternately expands and contracts, and excites the sandwich-type longitudinal-bending composite piezoelectric actuator to generate bending vibration, thereby exciting the ring to generate an in-plane bending vibration mode, and the contact position between the amplitude transformer and the ring is the peak or trough position of the bending vibration mode of the ring;

[0021] Step 203, the phase difference of the two-phase in-plane bending vibration modes of the ring in time and space is 90°, so after superposition, an in-plane bending traveling wave is formed, and the particle point on the surface of the ring is an elliptical motion trajectory, and then the track is driven to move through the friction contact between the ring and the metal track.

[0022] A further improvement of the present invention is that the sinusoidal excitation voltage V(t)=V pp sin(2πft), the other phase sinusoidal excitation voltage V(t)=V pp sin(2πft+π / 2);

[0023] Among them, V pp The peak-to-peak value of the meter voltage, f represents frequency, t represents time, the value range of f is greater than 20kHz, ω pp The value range is 10≤ω pp ≤300; changing the phase difference of the above two-phase sinusoidal excitation voltage to -π / 2 can change the movement direction of the metal track.

[0024] The present invention has at least the following beneficial technical effects:

[0025] The present invention provides a sandwich-type longitudinal-bending composite piezoelectric driven track device, in which the piezoelectric drive does not need a deceleration system, thus avoiding a cumbersome transmission system; in addition, the piezoelectric drive does not need a lubrication system; therefore, the track device driven by the piezoelectric drive has potential application prospects in special fields such as planetary exploration. A longitudinal-bending composite piezoelectric drive is adopted, and both the longitudinal vibration ceramic group and the bending vibration ceramic group are a whole piece of ceramic; the bending vibration ceramic piece is divided into left and right areas, and the middle dividing area is not polarized; the assembly complexity of half-piece ceramic is avoided, and the structure of the piezoelectric drive is simplified. The longitudinal-bending composite piezoelectric drive can adjust the relative position of the metal track and the piezoelectric drive ring by the relative position of the rear end cover and the mounting base, so as to facilitate changing the tension of the metal track.

[0026] The present invention provides a method for using a sandwich-type longitudinal-bending composite piezoelectric driven crawler device. The resonance frequencies of the two-phase bending vibration modes of the circular ring are consistent, and the phase difference in time and space is 90°. After superposition, an in-plane bending traveling wave is formed, and the particles on the surface of the circular ring are elliptical motion trajectories, and the track is driven to move through the friction contact between the circular ring and the metal crawler. The drive is simple and the principle is easy to understand. When the phase difference of the two-phase sinusoidal excitation voltage is changed from π / 2 to -π / 2, the traveling wave formed on the circular ring will run in the opposite direction, which can easily change the movement direction of the metal crawler.

[0027] In summary, the present invention avoids the gear transmission system, lubrication system, and structures such as sprockets, idler wheels, and road wheels used in traditional track travel systems. Based on the unique advantages of the sandwich-type longitudinal-bending composite piezoelectric drive, the piezoelectric-driven track device has the advantages of simple and compact structure, fast travel speed, flexible design, high energy density, strong environmental adaptability, and high drive efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the sandwich-type longitudinal-bending composite piezoelectric driven crawler device of the present invention.

[0029] Figure 2 It is a schematic structural diagram of the sandwich-type longitudinal-bending composite piezoelectric actuator of the present invention.

[0030] Figure 3 It is a structural schematic diagram of the fixed base of the present invention.

[0031] Figure 4 It is a schematic diagram of the structure of the crawler of the present invention.

[0032] Figure 5 Schematic diagram of the longitudinal vibration and bending vibration ceramic group of the sandwich longitudinal bending composite piezoelectric actuator of the present invention, wherein Figure 5 (a) is the longitudinal vibration piezoelectric ceramic group, Figure 5 (b) is the bending vibration piezoelectric ceramic group.

[0033] Figure 6 It is a schematic diagram of the use method of the sandwich type longitudinal bending composite piezoelectric driven crawler device of the present invention. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

[0035] like Figures 1 to 5 As shown, the present invention provides a sandwich-type longitudinal-bending composite piezoelectric drive track device, comprising a driver mounting base 2, a metal track 3 and three identical longitudinal-bending composite piezoelectric drivers 1; wherein the driver mounting base 2 is arranged on the inner side of the metal track 3, and the three longitudinal-bending composite piezoelectric drivers are rotationally symmetrically arranged on the circumference of the driver mounting base 2 and in contact with the inner side of the metal track 3; one end of each longitudinal-bending composite piezoelectric driver 1 is mounted on the rear end cover 1-1 on the driver mounting base 2, and the other end is a piezoelectric driver ring 1-2 in contact with the inner side of the metal track 3, and the longitudinal-bending composite piezoelectric driver 1 can adjust the relative position of the metal track 3 and the piezoelectric driver ring 1-2 through the relative position of the rear end cover 1-1 and the mounting base 2, thereby changing the tension of the metal track 3.

[0036] like Figure 3 As shown, the driver mounting base 2 includes a fixed base 2-1 and three movable bases 2-2 arranged in rotational symmetry along the circumference of the fixed base 2-1. The fixed base 2-1 is provided with a T-shaped groove 2-1-1 for the rear end cover 1-1 to move toward or away from the rotating metal track 3, and the movable base 2-2 can be in the corresponding T-shaped groove 2-1-1.

[0037] like Figure 2 As shown, each longitudinal-bending composite piezoelectric driver 1 includes a rear end cover 1-1, a piezoelectric driver ring 1-2, a longitudinal vibration piezoelectric ceramic group 1-4, a bending vibration piezoelectric ceramic group 1-5, a stud 1-6, and a horn 1-3 integrated with the piezoelectric driver ring 1-2. The longitudinal vibration piezoelectric ceramic group 1-4 and the bending vibration piezoelectric ceramic group 1-5 are sandwiched between the horn 1-3 and the rear end cover 1-1. Each longitudinal vibration ceramic of the longitudinal vibration piezoelectric ceramic group 1-4 is a whole piece of ceramic, and the polarization directions of the two adjacent piezoelectric ceramics 1-4 are opposite. Each longitudinal vibration ceramic of the bending vibration piezoelectric ceramic group 1-5 is a whole piece of ceramic, and the polarization directions of the two adjacent piezoelectric ceramics 1-5 are opposite. Each ceramic of the longitudinal vibration piezoelectric ceramic group 1-4 and the bending vibration piezoelectric ceramic group 1-5 is an annular ceramic, and the ceramic passes through the stud 1-6 and is clamped between the rear end cover 1-1 and the horn 1-3 by thread pre-tightening.

[0038] The present invention provides a method for using a sandwich-type longitudinal-bending composite piezoelectric driven crawler device, comprising the following steps:

[0039] Step 1: Assembly and adjustment of sandwich-type longitudinal-bending composite piezoelectric actuator:

[0040] Step 101, the longitudinal vibration piezoelectric ceramic group 1-4 is clamped between the amplitude transformer 1-3 and the stud 1-6 by threaded connection, the bending vibration piezoelectric ceramic group 1-5 is clamped between the stud 1-6 and the rear end cover 1-1 by threaded connection, and each ceramic piece of the longitudinal vibration piezoelectric ceramic group 1-4 and the bending vibration piezoelectric ceramic group 1-5 is respectively bonded by epoxy resin glue;

[0041] Step 102, installing a movable base 2-2 on the fixed base 2-1 of the installation base 2, and installing a sandwich-type longitudinal-bending composite piezoelectric driver on the movable base 2-2;

[0042] Step 103, adjusting the position between the sandwich-type longitudinal-bending composite piezoelectric actuator and the actuator mounting base 2 to adjust the preload force between the contact surface of the piezoelectric actuator ring 1-2 and the metal track 3; wherein the three sandwich-type longitudinal-bending composite piezoelectric actuators 1 are arranged in rotational symmetry, and the piezoelectric actuator ring 1-2 is tangent to and in contact with the metal track 3;

[0043] Step 2: Apply two-phase sinusoidal excitation voltage and track movement to the sandwich type longitudinal bending composite piezoelectric drive track device:

[0044] Step 201, applying a sinusoidal excitation voltage to the longitudinal vibration piezoelectric ceramic group 1-4 of the sandwich longitudinal bending composite piezoelectric actuator 1, the longitudinal vibration piezoelectric ceramic group 1-4 is extended and retracted along the axial direction of the sandwich longitudinal bending composite piezoelectric actuator 1, and the sandwich longitudinal bending composite piezoelectric actuator 1 is stimulated to generate longitudinal vibration, thereby stimulating the ring to generate an in-plane bending vibration mode, and the contact position between the amplitude rod and the ring is the node position of the bending vibration mode of the ring;

[0045] Step 202, applying another sinusoidal excitation voltage with a phase difference of 90° to the bending vibration piezoelectric ceramic group 1-5 of the sandwich type longitudinal bending composite piezoelectric actuator 1, the bending vibration piezoelectric ceramic group 1-5 alternately expands and contracts, and excites the sandwich type longitudinal bending composite piezoelectric actuator 1 to generate bending vibration, thereby exciting the ring to generate an in-plane bending vibration mode, and the contact position between the amplitude rod and the ring is the peak or trough position of the bending vibration mode of the ring;

[0046] Step 203, the phase difference of the two-phase in-plane bending vibration modes of the ring in time and space is 90°, so after superposition, an in-plane bending traveling wave is formed, and the particle point on the surface of the ring is an elliptical motion trajectory, and then the track is driven to move through the friction contact between the ring and the metal track.

[0047] The sinusoidal excitation voltage V(t)=V pp sin(2πft), the other phase sinusoidal excitation voltage V(t)=V ppsin(2πft+π / 2); where V pp The peak-to-peak value of the meter voltage, f represents frequency, t represents time, the value range of f is greater than 20kHz, ω pp The value range is 10≤ω pp ≤300; changing the phase difference of the above two-phase sinusoidal excitation voltage to -π / 2 can change the movement direction of the metal track.

[0048] Example

[0049] like Figure 6 As shown, take n=5, the first electrical signal is a cosine signal, and the second electrical signal is a sine signal as an example.

[0050] Modifications and additions:

[0051] like Figure 6 As shown, take n=5, the first electrical signal is a sine signal, and the second electrical signal is a cosine signal as an example.

[0052] A sinusoidal excitation voltage is applied to the longitudinal vibration piezoelectric ceramic group of the sandwich longitudinal-bending composite piezoelectric actuator, and the longitudinal vibration piezoelectric ceramic group expands and contracts along the axial direction of the sandwich longitudinal-bending composite piezoelectric actuator, thereby exciting the piezoelectric actuator to generate longitudinal vibration, thereby exciting the ring to generate a fifth-order bending vibration mode in the plane, and the contact position between the amplitude transformer and the ring is located at the node position of the fifth-order bending vibration mode of the ring;

[0053] Another cosine excitation voltage with a phase difference of 90° is applied to the bending vibration piezoelectric ceramic group of the sandwich-type longitudinal-bending composite piezoelectric actuator, and the bending vibration piezoelectric ceramic group is alternately expanded and contracted, thereby stimulating the sandwich-type longitudinal-bending composite piezoelectric actuator to produce bending vibration, thereby stimulating the circular ring to produce an in-plane 5th-order bending vibration mode, and the contact position between the amplitude transformer and the circular ring is the peak or trough position of the 5th-order bending vibration mode of the circular ring.

[0054] The phase difference of the five-order bending vibration modes in the two-phase plane of the ring in time and space is 90°, so after superposition, an in-plane bending traveling wave is formed, and the particles on the surface of the ring have an elliptical motion trajectory, and the track movement is driven by the friction contact between the ring and the metal track.

[0055] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A sandwich type longitudinal bending composite piezoelectric driven crawler device, characterized in that: It comprises a driver mounting base (2), a metal track (3) and three identical longitudinal-bending composite piezoelectric drivers (1); wherein: The driver mounting base (2) is arranged on the inner side of the metal crawler (3), and three longitudinal-bending composite piezoelectric drivers are arranged rotationally symmetrically on the circumference of the driver mounting base (2) and are in contact with the inner side of the metal crawler (3); One end of each longitudinal-bending composite piezoelectric driver (1) is mounted on a rear end cover (1-1) on a driver mounting base (2), and the other end is a piezoelectric driver ring (1-2) in contact with the inner side of a metal track (3), and the longitudinal-bending composite piezoelectric driver (1) can adjust the relative position of the metal track (3) and the piezoelectric driver ring (1-2) by adjusting the relative position of the rear end cover (1-1) and the mounting base (2), thereby changing the tension of the metal track (3); The driver mounting base (2) comprises a fixed base (2-1) and three movable bases (2-2) arranged in a rotationally symmetrical manner along the circumference of the fixed base (2-1); The fixed base (2-1) is provided with a T-shaped groove (2-1-1) for the rear end cover (1-1) to move toward or away from the rotating metal track (3), and the movable base (2-2) can be in the corresponding T-shaped groove (2-1-1); Each longitudinal-bending composite piezoelectric driver (1) comprises a rear end cover (1-1), a piezoelectric driver ring (1-2), a longitudinal vibration piezoelectric ceramic group (1-4), a bending vibration piezoelectric ceramic group (1-5), a double-headed stud (1-6), and an amplitude change rod (1-3) integrated with the piezoelectric driver ring (1-2); the longitudinal vibration piezoelectric ceramic group (1-4) and the bending vibration piezoelectric ceramic group (1-5) are sandwiched between the amplitude change rod (1-3) and the rear end cover (1-1); each longitudinal vibration ceramic of the longitudinal vibration piezoelectric ceramic group (1-4) is a whole piece of ceramic, and the polarization directions of two adjacent longitudinal vibration piezoelectric ceramics are opposite; each longitudinal vibration ceramic of the bending vibration piezoelectric ceramic group (1-5) is a whole piece of ceramic, and the polarization directions of two adjacent bending vibration piezoelectric ceramics are opposite; Each piece of ceramic in the longitudinal vibration piezoelectric ceramic group (1-4) and the bending vibration piezoelectric ceramic group (1-5) is annular ceramic, and the ceramic passes through the double-headed stud (1-6) and is clamped between the rear end cover (1-1) and the amplitude transformer (1-3) by thread pre-tightening.

2. A method for using a sandwich type longitudinal bending composite piezoelectric driven crawler device, characterized in that: The method of use is based on a sandwich-type longitudinal-bending composite piezoelectric driven crawler device as described in claim 1, and comprises the following steps: Step 1: Assembly and adjustment of sandwich-type longitudinal-bending composite piezoelectric actuator: Step 101, the longitudinal vibration piezoelectric ceramic group (1-4) is clamped between the amplitude transformer (1-3) and the stud bolt (1-6) by threaded connection, the bending vibration piezoelectric ceramic group (1-5) is clamped between the stud bolt (1-6) and the rear end cover (1-1) by threaded connection, and each ceramic piece of the longitudinal vibration piezoelectric ceramic group (1-4) and the bending vibration piezoelectric ceramic group (1-5) is respectively bonded by epoxy resin glue; Step 102, installing a movable base (2-2) on the fixed base (2-1) of the installation base (2), and installing a sandwich-type longitudinal-bending composite piezoelectric driver on the movable base (2-2); Step 103, adjusting the position between the sandwich-type longitudinal-bending composite piezoelectric actuator and the actuator mounting base (2) to adjust the preload force between the contact surface of the piezoelectric actuator ring (1-2) and the metal crawler (3); wherein the three sandwich-type longitudinal-bending composite piezoelectric actuators (1) are arranged in rotational symmetry, and the piezoelectric actuator ring (1-2) is tangent to and in contact with the metal crawler (3); Step 2: Apply two-phase sinusoidal excitation voltage and track movement to the sandwich type longitudinal bending composite piezoelectric drive track device: Step 201, applying a sinusoidal excitation voltage to the longitudinal vibration piezoelectric ceramic group (1-4) of the sandwich longitudinal bending composite piezoelectric actuator (1), so that the longitudinal vibration piezoelectric ceramic group (1-4) expands and contracts along the axial direction of the sandwich longitudinal bending composite piezoelectric actuator (1), thereby exciting the sandwich longitudinal bending composite piezoelectric actuator (1) to generate longitudinal vibration, thereby exciting the ring to generate an in-plane bending vibration mode, and the contact position between the amplitude rod and the ring is the node position of the bending vibration mode of the ring; Step 202, applying another sinusoidal excitation voltage with a phase difference of 90° to the bending vibration piezoelectric ceramic group (1-5) of the sandwich type longitudinal bending composite piezoelectric actuator (1), so that the bending vibration piezoelectric ceramic group (1-5) alternately expands and contracts, thereby exciting the sandwich type longitudinal bending composite piezoelectric actuator (1) to generate bending vibration, thereby exciting the ring to generate an in-plane bending vibration mode, and the contact position between the amplitude rod and the ring is the peak or trough position of the bending vibration mode of the ring; Step 203, the phase difference of the two-phase in-plane bending vibration modes of the ring in time and space is 90°, so after superposition, an in-plane bending traveling wave is formed, and the particle point on the surface of the ring is an elliptical motion trajectory, and then the track is driven to move through the friction contact between the ring and the metal track.

3. The method for using the sandwich type longitudinal bending composite piezoelectric driven crawler device according to claim 2, characterized in that: The sinusoidal excitation voltage V(t)=V pp sin(2πft), the other phase sinusoidal excitation voltage V(t)=V pp sin(2πft+π / 2); Among them, V pp The peak-to-peak value of the meter voltage, f represents frequency, t represents time, the value range of f is greater than 20kHz, ω pp The value range is 10≤ω pp ≤300; changing the phase difference of the above two-phase sinusoidal excitation voltage to -π / 2 can change the movement direction of the metal track.

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