CN-122001241-A - Sandwich type piezoelectric driven double-shaft output mobile robot and working method thereof

CN122001241ACN 122001241 ACN122001241 ACN 122001241ACN-122001241-A

Abstract

The invention discloses a sandwich type piezoelectric driven double-shaft output mobile robot and a working method thereof, the sandwich type piezoelectric driven double-shaft output mobile robot comprises a sandwich type piezoelectric transducer, a precompression applying mechanism, a driving wheel unit, a first output shaft, a second output shaft, a base frame and a connecting plate, wherein a clamping mechanism is not arranged on a stator base of the sandwich type piezoelectric transducer, a single pin of the precompression applying mechanism is restrained with a through hole in the middle of a stator node beam, automatic rolling transmission of contact force is realized under the condition of pin hole matching, precompression transmitted by the precompression applying mechanism is realized, force balance is realized under the reaction force of the first driving foot and the second driving foot of the sandwich type piezoelectric transducer, which are contacted with curved surfaces of the output shafts, the elliptical motion track direction of the stator driving foot can be controlled by controlling the phase difference of electric signals of a longitudinal vibration piezoelectric ceramic group and a bending vibration piezoelectric ceramic group, and forward and backward motion of the first output shaft and the second output shaft are realized through friction contact.

Inventors

ZENG ZHIQIN
WANG LIANG
Yang Pantao
LI MENG
JIN JIAMEI

Assignees

南京航空航天大学

Dates

Publication Date: 20260508
Application Date: 20260128

Claims (9)

1. The sandwich type piezoelectric driven double-shaft output mobile robot is characterized by comprising a sandwich type piezoelectric transducer, a precompression applying mechanism, a driving wheel unit, a first output shaft, a second output shaft, a matrix frame and a connecting plate; The sandwich type piezoelectric transducers are horizontally arranged, the driving feet face the rotating shafts, the single mobile robot comprises E sandwich type piezoelectric transducers, E is an integer larger than 1, and each sandwich type piezoelectric transducer comprises a piezoelectric unit, a node beam, a front end cover, a rear end cover and a pre-tightening bolt; the piezoelectric unit comprises a longitudinal vibration piezoelectric unit and a bending vibration piezoelectric unit, wherein the piezoelectric ceramic is in a structural form of square sheet round holes or round disc round holes, the longitudinal vibration piezoelectric unit is single-partition piezoelectric ceramic, 2 pieces are in a group, and are arranged at node positions of the longitudinal vibration modes, the longitudinal vibration modes are odd-order, the polarization directions of two adjacent pieces of ceramic pieces are opposite, the longitudinal vibration piezoelectric unit comprises 2N groups of ceramic pieces, N is an integer greater than 1, the polarization directions of the longitudinal vibration piezoelectric ceramic pieces are symmetrically distributed at two sides of a node beam, the bending vibration piezoelectric unit is double-partition piezoelectric ceramic, 2 pieces are in a group, the bending vibration mode is in an even-order mode greater than two-order mode, the polarization directions of two adjacent pieces of piezoelectric ceramic pieces are opposite, and the bending vibration piezoelectric unit comprises 2M groups of ceramic pieces, wherein the polarization directions of the piezoelectric ceramic pieces are in an integer greater than 1, and are symmetrically distributed at two sides of the node beam; The pre-compression force applying mechanism is integrally of a closed frame-shaped structure, a hinge support hole is arranged on the left side of the frame-shaped structure to realize rotation around the hole, the middle section of the frame-shaped structure is a metal block protruding inwards and matched with the front side and the rear side of a node beam of the sandwich-type piezoelectric transducer to limit the displacement of the transducer along the radial direction, the right side of the frame-shaped structure is of a rectangular plate structure, the center of the rectangular plate is provided with an upper through hole and a lower through hole, a pre-compression bolt penetrates through the hole, the upper surface of the rectangular plate is in contact with a spring, and the pre-compression force is applied by extruding the spring; The driving wheel unit comprises 4 driving wheels, each driving wheel comprises an inner hub, an outer hub and a plurality of spokes, wherein the inner hub and the outer hub are coaxial, and the middle of the inner hub is connected with the spokes; The first output shaft and the second output shaft are coaxial stepped rotating shafts, the diameters of the shafts are large in the middle and small in the two ends, the left end and the right end of the shafts are symmetrically arranged, the curved surface of the middle section of the output shaft is contacted with the driving foot of the sandwich type piezoelectric transducer to form a friction driving pair relationship, the end face of the second step of the output shaft is contacted with the inner ring of the rotating bearing, so that the limit of axial displacement is realized, and the last step of the output shaft is matched with the inner hub of the driving wheel to realize the output of rotational displacement; The matrix frame is composed of three metal plate structures and comprises a bottom plate and two parallel vertical plates, wherein the whole bottom plate is rectangular, connecting holes are distributed at the four corners, the vertical plates are distributed at two sides of the bottom plate, and are symmetrically distributed about the center of the bottom plate, two through holes are formed below the vertical plates and are matched with bearings of an output shaft; the connecting plate is a rectangular plate, and is penetrated by 3 holes in parallel, the middle hole is a bolt hole and is matched with a bolt of the precompression applying device, the holes at the two ends are through holes, and the connecting plate is matched with a bolt mounting hole on the base body frame to realize fixation.
2. The sandwich-type piezo-driven biaxial mobile robot according to claim 1, wherein the sandwich-type piezo-electric transducer itself has no clamping mechanism and is restrained only by the upper hole of the node beam.
3. The sandwich-type piezo-driven biaxial mobile robot of claim 1 wherein the first and second driving feet of the sandwich-type piezo-electric transducer are geometrically identical, and the cross-sectional shape of both driving feet comprises convex, planar and concave.
4. The sandwich-type piezoelectric driven biaxial mobile robot of claim 1, wherein the front end cover, the node beam and the rear end cover of the sandwich-type piezoelectric transducer are all made of metal materials.
5. The sandwich-type piezo-driven biaxial mobile robot of claim 1 wherein the intermediate section inward protruding portion of the pre-pressure applying mechanism mates with the transducer nodal beam with a gap consistent with the nodal beam width.
6. The sandwich-type piezo-electrically driven bi-axial mobile robot of claim 1, wherein the length of the intermediate section of the first and second output shafts is greater than the length of the first and second drive legs of the sandwich-type piezo-electric transducer.
7. The sandwich-type piezoelectric driven biaxial mobile robot according to claim 1, wherein the curved surfaces of the middle sections of the first output shaft and the second output shaft are matched with the first driving foot and the second driving foot of the sandwich-type piezoelectric transducer respectively, and the matching mode comprises the tangency of the curved surfaces and the curved surfaces, the tangency of a single plane and the curved surfaces and the tangency of a double plane and the curved surfaces.
8. The sandwich-type piezo-electrically driven biaxial mobile robot of claim 1, wherein the sandwich-type piezo-electric transducer is an independent unit, and can be operated independently, or can be operated in series or in parallel with a plurality of sandwich-type piezo-electric transducers.
9. The sandwich type piezoelectric driven biaxial mobile robot and the working method thereof as claimed in claim 1, which is characterized in that the method comprises the following steps: Applying a signal A to all piezoelectric ceramic plates generating longitudinal vibration and applying a signal B to all piezoelectric ceramic plates generating bending vibration, wherein the phase difference of the signal A and the signal B in time phase is pi/2, so that the sandwich type piezoelectric transducer excites an odd-order longitudinal vibration mode and an even-order bending vibration mode with the phase difference in time pi/2, and further the surface mass points of the first driving foot and the second driving foot generate micro-amplitude motion with the same rotation direction; the phase difference of the signal A and the signal B in time phase is changed to 3 pi/2, the particle motion directions on the surfaces of the first driving foot and the second driving foot are opposite, and the first output shaft and the second output shaft reversely rotate under the action of friction force.

Description

Sandwich type piezoelectric driven double-shaft output mobile robot and working method thereof Technical Field The invention relates to the technical field of piezoelectric actuation and multi-axis mobile robots, in particular to a sandwich type piezoelectric driven double-axis output mobile robot and a working method thereof. Background The lunar exploration vehicle is an important tool for lunar exploration and cargo transportation, and the driving mode is mainly electromagnetic motors. The lunar exploration vehicle has the advantages of strong obstacle crossing capability, convenience in control and the like, and has important application in the aspects of lunar soil component analysis, lunar surface feature exploration and the like. The small star such as moon has smaller diameter, so that the gravitational acceleration of objects on the surface is only 1/6 of that of the earth, which leads to that tiny particles on the surface of the moon are easy to float upwards and stay for a long time, and for the driving modes such as an electromagnetic motor, once the tiny particles enter the motor, the motor is blocked and the task is invalid, and the piezoelectric driving actuator is driven by high-frequency friction, even if the tiny particles exist, the piezoelectric driving actuator can be separated, and the motor and the moving trolley cannot be influenced. In some existing piezoelectric actuator lunar rover solutions (publication number: CN109334794; CN 105429508), the piezoelectric transducer is in direct contact with the drive wheel, and the transducer also serves as part of the lunar rover drive chassis. The pre-pressure of the piezoelectric transducer and the driving wheel is applied by adjusting the displacement of the driving wheel along the axial direction of the transducer, and the lunar rover is subjected to external load in the driving process, so that the contact pre-pressure is changed, and the driving performance of the lunar rover is caused to generate output performance fluctuation, idling and unstable phenomena, so that the stable contact pre-pressure is difficult to realize. Disclosure of Invention The invention aims to solve the technical problem of providing a sandwich type piezoelectric driven double-shaft output mobile robot and a working method thereof aiming at the defects related to the background technology. The invention adopts the following technical scheme for solving the technical problems: the sandwich type piezoelectric driven double-shaft output mobile robot is characterized by comprising a sandwich type piezoelectric transducer, a precompression applying mechanism, a driving wheel unit, a first output shaft, a second output shaft, a matrix frame and a connecting plate; The sandwich type piezoelectric transducers are horizontally arranged, the driving feet face the rotating shafts, the single mobile robot comprises E sandwich type piezoelectric transducers, E is an integer larger than 1, and each sandwich type piezoelectric transducer comprises a piezoelectric unit, a node beam, a front end cover, a rear end cover and a pre-tightening bolt; the piezoelectric unit comprises a longitudinal vibration piezoelectric unit and a bending vibration piezoelectric unit, wherein the piezoelectric ceramic is in a structural form of square sheet round holes or round disc round holes, the longitudinal vibration piezoelectric unit is single-partition piezoelectric ceramic, 2 pieces are in a group, and are arranged at node positions of the longitudinal vibration modes, the longitudinal vibration modes are odd-order, the polarization directions of two adjacent pieces of ceramic pieces are opposite, the longitudinal vibration piezoelectric unit comprises 2N groups of ceramic pieces, N is an integer greater than 1, the polarization directions of the longitudinal vibration piezoelectric ceramic pieces are symmetrically distributed at two sides of a node beam, the bending vibration piezoelectric unit is double-partition piezoelectric ceramic, 2 pieces are in a group, the bending vibration mode is in an even-order mode greater than two-order mode, the polarization directions of two adjacent pieces of piezoelectric ceramic pieces are opposite, and the bending vibration piezoelectric unit comprises 2M groups of ceramic pieces, wherein the polarization directions of the piezoelectric ceramic pieces are in an integer greater than 1, and are symmetrically distributed at two sides of the node beam; The pre-compression force applying mechanism is integrally of a closed frame-shaped structure, a hinge support hole is arranged on the left side of the frame-shaped structure to realize rotation around the hole, the middle section of the frame-shaped structure is a metal block protruding inwards and matched with the front side and the rear side of a node beam of the sandwich-type piezoelectric transducer to limit the displacement of the transducer along the radial direction, the right side of the frame-shaped