Piezoelectric robot based on ring-beam composite structure and excitation method thereof

Abstract

The invention belongs to the technical field of piezoelectric robots, and particularly relates to a piezoelectric robot based on a ring-beam combined structure and an excitation method thereof.The piezoelectric robot comprises a base body and a piezoelectric element fixedly arranged on the base body, the base body is composed of a square ring in a square shape and a beam fixedly arranged at the center of the square ring, and the piezoelectric element is arranged on the base body. The end part of the beam is a spherical tail end; the piezoelectric element comprises four rectangular piezoelectric patches and an annular piezoelectric patch, the four rectangular piezoelectric patches are evenly distributed on the side face of the beam in the circumferential direction of the beam, and the annular piezoelectric patch is fixedly arranged on the end face of the end, away from the beam, of the square ring. And an auxiliary supporting mechanism is arranged outside the square ring. The problem that a longitudinal vibration mode and a bending vibration mode in a traditional square beam structure are difficult to couple is effectively solved. And the structural configuration of the single driving foot is adopted, so that the overall structure of the robot is more compact. According to the design scheme of the ring-beam combined structure, the robot finally achieves rapid, accurate and flexible movement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of piezoelectric robots, and particularly relates to a piezoelectric robot based on a ring-beam combined structure and an excitation method thereof. BACKGROUND

[0002] In recent years, micro robots have attracted extensive attention. With their small size, high agility and good environmental adaptability, they can perform complex tasks in confined spaces and have broad application prospects in the fields of biomedical, industrial detection and disaster rescue. Rotary motors are the most commonly used driving form of robots. They have fast response speed, are easy to control, and can provide stable and efficient power output. However, the demand for complex control and transmission systems limits their miniaturization. At the same time, due to factors such as friction or gear gap, such robots are prone to large errors when performing fine operations. Smart materials have opened up new ways for the development of micro robots. Current research focuses on the innovative application of materials such as dielectric elastomers, shape memory alloys, liquid crystal elastomers and piezoelectric materials. Among them, dielectric elastomers require very high voltage to produce sufficient deformation; shape memory alloys have slow response and poor durability; the driving force of liquid crystal elastomers is usually small and sensitive to external environment. Piezoelectric drivers have fast response speed, high energy conversion efficiency, excellent positioning accuracy and good electromagnetic compatibility, and have become the preferred solution for micro robot driving systems.

[0003] According to whether working in a resonant state, piezoelectric robots can be divided into non-resonant and resonant types. The step distance of the former can be accurately controlled at the nanometer level, but the low speed and limited movement range limit its application. In contrast, the movement range of the resonant piezoelectric robot is large, and it is easier to achieve high-speed movement. For resonant piezoelectric robots, miniaturization, flexibility, running efficiency (including speed and accuracy), load capacity, and driving operability are key design indicators. Among them, the movement flexibility, i.e. the ability to achieve multi-degree-of-freedom movement, is an especially important factor in robot design, as it directly determines the movement range and the ability to adapt to complex environments. In order to improve the movement flexibility, the driving foot should be able to generate a multi-dimensional driving trajectory. However, due to the large longitudinal stiffness and small bending stiffness of the traditional beam structure, it is difficult to achieve the coupling of longitudinal and bending vibration modes, thereby unable to directly generate a multi-dimensional trajectory. To solve this problem, a common approach is to parallel multiple piezoelectric drivers that can achieve single-degree-of-freedom movement to achieve multi-degree-of-freedom movement. This approach makes the size of the robot grow exponentially, complicates the structure, and increases the difficulty of assembly and control. Another method is to develop robots using structures with multi-modal vibration capabilities. For example, a circular ring structure naturally has multiple vibration modes such as radial and axial, making it easy to achieve modal coupling and generate complex driving trajectories. However, such robots usually need to arrange multiple driving feet to achieve stable movement, making them sensitive to processing and assembly errors and prone to movement stability problems such as poor linearity. In addition, in order to ensure the task execution capability of the robot, it also needs to have a certain load carrying capacity, while requiring lower driving difficulty, such as not too high driving frequency. However, these performance indicators often have mutual constraints and contradictions. Therefore, traditional piezoelectric robots represented by standard configurations such as square beam structures face great challenges in achieving multi-performance balance. Exploring design schemes for multi-performance integration of micro piezoelectric robots is of great significance for expanding their applications in complex scenarios. SUMMARY

[0004] In view of the technical problems of current piezoelectric robot configurations being complex, movement performance being limited, flexibility being insufficient, and driving difficulty being high, the present application reduces the longitudinal stiffness of the entire structure by installing a square ring on the top of the beam structure, thereby reducing the longitudinal resonant frequency to close to the bending resonant frequency of the beam, achieving the coupling of longitudinal and bending modes, and avoiding the problem of high driving difficulty caused by high driving frequency.

[0005] The technical scheme adopted by the present application is as follows: a piezoelectric robot based on a ring-beam combined structure, comprising a base body and a piezoelectric element fixedly arranged on the base body, wherein the base body comprises a square ring and a beam fixedly arranged at the center of the square ring; the square ring is in a mouth-shaped type, and a support beam is fixedly arranged in the square ring; one end of the beam is fixedly connected to the center of the support beam through a transition beam, and the other end of the beam is a spherical end; the piezoelectric element comprises four rectangular piezoelectric sheets and a ring-shaped piezoelectric sheet; the four rectangular piezoelectric sheets are uniformly distributed on the side surface of the beam along the circumferential direction of the beam; the ring-shaped piezoelectric sheet is the same in shape as the square ring, and is fixedly arranged on the end surface of the square ring away from the beam; an auxiliary support mechanism is arranged on the outside of the square ring; the auxiliary support mechanism is provided with a plurality of support legs for supporting the ground; a rotatable passive wheel is arranged on each support leg; and the plurality of passive wheels and the spherical end of the beam form passive feet and active feet of the piezoelectric robot, respectively.

[0006] Further, the side surface of the beam is rectangular.

[0007] Further, the support beam is in a cross-shaped or rice-shaped type.

[0008] Further, the base body is integrally formed.

[0009] Further, the piezoelectric element is a piezoelectric ceramic or a piezoelectric polymer.

[0010] Further, the auxiliary support mechanism comprises a fixed box body and a support frame fixedly arranged on the fixed box body; the fixed box body comprises a fixed frame and a support frame, and the fixed frame and the support frame are buckled on the outside of the square ring in a bolt connection mode; the support frame is fixedly arranged on the support frame; the support frame is provided with a plurality of support legs for supporting the ground; and a rotatable wheel is arranged on each support leg.

[0011] The present application also provides a two-degree-of-freedom in-plane motion excitation method based on the piezoelectric robot, which comprises the following contents.

[0012] Firstly, a global coordinate system O-XYZ is set for the entire piezoelectric robot, wherein:

[0013] The spherical end of the beam is taken as the origin O of the global coordinate system;

[0014] The plane formed by the X-axis and the Z-axis is taken as the ground, and the downward direction perpendicular to the ground is taken as the positive direction of the Y-axis, and vice versa;

[0015] The direction of the fourth locking bolt pointing to the second locking bolt is taken as the positive direction of the Z-axis, and vice versa;

[0016] The direction of the third locking bolt pointing to the direction of the first locking bolt is the positive direction of the X axis, and vice versa is the negative direction of the X axis;

[0017] The overall coordinate system o-xyz is set for the base body, wherein:

[0018] The spherical end of the beam is taken as the origin o of the overall coordinate system;

[0019] The direction perpendicular to the upper surface of the square ring and downward is the positive direction of the y axis, and vice versa is the negative direction of the y axis;

[0020] The direction of the third rectangular piezoelectric sheet pointing to the direction of the first rectangular piezoelectric sheet is the positive direction of the x axis, and vice versa is the negative direction of the x axis;

[0021] The direction of the fourth rectangular piezoelectric ceramic sheet pointing to the direction of the second rectangular piezoelectric sheet is the positive direction of the z axis, and vice versa is the negative direction of the z axis;

[0022] The local coordinate system o1-x1y1z1 is set in the base body, wherein:

[0023] The positive direction of the y1 axis is consistent with the positive direction of the y axis, the positive direction of the x1 axis is the combined direction of the positive direction of the x axis and the positive direction of the z axis, and the positive direction of the z1 axis is the combined direction of the negative direction of the x axis and the positive direction of the z axis;

[0024] Secondly, the polarization directions of the third rectangular piezoelectric sheet and the fourth rectangular piezoelectric sheet of the four rectangular piezoelectric sheets are set to be perpendicular to the side surface of the beam and inward, and the polarization directions of the first rectangular piezoelectric sheet and the second rectangular piezoelectric sheet are set to be perpendicular to the side surface of the beam and outward;

[0025] The polarization direction of the annular piezoelectric sheet is set to be perpendicular to the surface of the square ring and inward;

[0026] The first excitation signal is applied to the second rectangular piezoelectric sheet and the fourth piezoelectric sheet of the four rectangular piezoelectric sheets which are correspondingly arranged;

[0027] The second excitation signal is applied to the first rectangular piezoelectric sheet and the third rectangular piezoelectric sheet of the four rectangular piezoelectric sheets which are correspondingly arranged;

[0028] The third excitation signal is applied to the annular piezoelectric ceramic sheet;

[0029] The first excitation signal, the second excitation signal and the third excitation signal are all sine alternating voltage signals of the same frequency and amplitude;

[0030] Further, when it is needed to control the piezoelectric robot to move linearly along the positive direction of the Z axis, the second excitation signal lags behind the first excitation signal by one quarter of a period in time phase, and the third excitation signal leads the first excitation signal by one quarter of a period;

[0031] When the piezoelectric robot needs to be controlled to move along the Z-axis in a negative straight line: the second excitation signal is delayed by one quarter of a cycle in the time phase of the first excitation signal, and the third excitation signal is delayed by one quarter of a cycle in the time phase of the first excitation signal;

[0032] Further, when the piezoelectric robot needs to be controlled to rotate clockwise along the Y-axis: the second excitation signal is in phase with the first excitation signal in the time phase, and the third excitation signal leads the first excitation signal by one quarter of a cycle in the time phase;

[0033] When the piezoelectric robot needs to be controlled to rotate counterclockwise along the Y-axis: the second excitation signal is in phase with the first excitation signal in the time phase, and the third excitation signal lags the first excitation signal by one quarter of a cycle in the time phase.

[0034] Compared with the prior art, the piezoelectric robot and the motion excitation method thereof have the following beneficial effects:

[0035] 1. The piezoelectric robot based on the ring-beam combined structure is developed to meet the demand of multi-performance integration of the micro piezoelectric robot, and effectively solves the problem that the longitudinal vibration mode and the bending vibration mode are difficult to be coupled in the traditional square beam structure. Based on the mode coupling mechanism, the driving foot has the ability to generate a multi-dimensional oscillation trajectory. On this basis, a micro piezoelectric robot with two degrees of freedom is designed and implemented. Due to the use of the single driving foot structure configuration, the overall structure of the robot is more compact, small in size, and based on the piezoelectric driving technology, the driving foot can generate micron-level vibration, which is convenient for realizing high-precision motion. In addition, due to the small bending stiffness of the beam segment in the ring-beam combined structure, the driving foot can realize large amplitude oscillation, so that the robot can move at high speed. Thanks to the nearly vertical installation method, the piezoelectric robot has high stiffness in the longitudinal direction, so that it can carry heavy loads.

[0036] 2. The excitation scheme provided by the present application can make the driving foot oscillate quickly, thereby realizing flexible two-degree-of-freedom motion of the robot in the plane, and having low power consumption.

[0037] In general, the piezoelectric robot and the motion excitation method thereof provided in the present application achieve a good balance in terms of miniaturization, running efficiency, flexibility, load capacity, and driving operability, and the running power consumption is significantly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of the base body of the present application;

[0039] Figure 2 It is a rear view of Figure 1

[0040] Figure 3 ​This is a schematic diagram of the overall structure of a piezoelectric robot based on a ring-beam combination structure according to the present invention;

[0041] Figure 4 for Figure 3 Front view of

[0042] Figure 5 for Figure 3 A top view of

[0043] Figure 6 is a structural diagram of the support frame;

[0044] Figure 7 It is a structural diagram of a fixed frame;

[0045] Figure 8 Schematic diagram of the global coordinate system of a piezoelectric robot based on a ring-beam combination structure according to the present invention;

[0046] Figure 9 Schematic diagram of the global coordinate system and local coordinate system of the substrate of the present invention;

[0047] Description of reference numerals:

[0048] 1. Fixed box; 11. Fixed frame; 12. Support frame; 13. Positioning column; 2. Locking bolt; 21. First locking bolt; 22. Second locking bolt; 23. Third locking bolt; 24. Fourth locking bolt; 4. Rectangular piezoelectric sheet; 41. First rectangular piezoelectric sheet; 42. Second rectangular piezoelectric sheet; 43. Third rectangular piezoelectric sheet; 44. Fourth rectangular piezoelectric sheet; 5. Base; 51. Square ring; 52. Beam; 53. Support beam; 54. Transition beam; 6. Support frame; 61. Support leg; 7. Passive wheel; 8. Annular piezoelectric sheet. DETAILED DESCRIPTION

[0049] In order to better explain the present invention and facilitate understanding, the technical solution adopted by the present invention is described in detail below with reference to the accompanying drawings;

[0050] First, the present invention discloses a piezoelectric robot based on a ring-beam combination structure, comprising:

[0051] Base 5, such as Figures 1-2 As shown, the material of the base 5 in the present invention is a metal elastomer, which can be made of aluminum alloy or beryllium bronze. The base 5 is a ring-beam combination structure consisting of a square ring 51 and a beam 52 fixedly arranged at the center of the square ring 51, wherein:

[0052] The square ring 51 is in the shape of a square, and a support beam 53 is fixed inside it. The support beam 53 is used as a connection point between the beam 52 and the square ring 51. The shape of the support beam 53 is preferably a cross or a cross to improve the structural strength of the square ring 51.

[0053] The side surface of the beam 52 as the driving foot of the piezoelectric robot is preferably rectangular, one end of which is fixedly connected to the center of the supporting beam 53 through a cylindrical transition beam 54, and the beam 52 is perpendicular to the plane of the square ring 51, and the other end of the beam 52 is a spherical end, so as to facilitate the movement of the driving foot on the ground;

[0054] Preferably, the base 5 can also be provided by the above structure by integrated molding.

[0055] The piezoelectric element in the present application is a material having stress-voltage conversion function, such as piezoelectric ceramic or piezoelectric polymer, which includes a rectangular piezoelectric sheet 4 and a ring-shaped piezoelectric sheet 8, wherein:

[0056] The rectangular piezoelectric sheet 4 is provided with four, which are matched with the side surface of the beam 52, respectively, the first shape piezoelectric sheet 41, the second shape piezoelectric sheet 42, the third shape piezoelectric sheet 43, and the fourth shape piezoelectric sheet 44, and the four rectangular piezoelectric sheets 4 are thin and flat, which can be uniformly distributed on the side surface of the beam 52 by using adhesion, welding and other methods;

[0057] The ring-shaped piezoelectric sheet 8 is the same as the shape of the square ring 51, which can also be fixedly arranged on the end face of the square ring 51 away from the beam 52 by using adhesion, welding and other methods;

[0058] Specifically, the present application sets the ring-shaped piezoelectric sheet 8 and the four rectangular piezoelectric sheets 4 on the side surface of the square ring 51 and the beam 52 respectively, to form the actuator of the piezoelectric robot, and the beam 52 as the driving foot provides driving force for the robot, and by applying corresponding excitation signals to the ring-shaped piezoelectric sheet 8 and the four rectangular piezoelectric sheets 4, the driving foot will deform in the bending and longitudinal direction. When the frequency of the excitation signal is approximately equal to the resonant frequency, the driving foot will produce a larger amplitude of oscillation. Due to the coupling effect of bending and longitudinal modes, the driving foot will generate an elliptical trajectory. When the driving foot oscillates along the trajectory, friction with the ground is generated, and the reverse friction force exerted by the ground pushes the robot to move.

[0059] In addition, in order to ensure the stability of the piezoelectric robot moving in the plane, an auxiliary support mechanism needs to be provided on the base 5, such as Figures 3-5 As shown, the auxiliary support structure includes a fixed box 1 and a support frame 6 fixedly arranged on the fixed box 1, wherein:

[0060] The fixed box 1 is fixedly arranged outside the square ring 51 in a top-down buckling manner, and is provided with a detachable fixed frame 11 and a supporting frame 12. A plurality of connecting holes are arranged on the fixed frame 11 and the supporting frame 12 in correspondence, and the fixed frame 11 and the supporting frame 12 are fixed by being screwed with nuts through lock bolts 2 inserted into the plurality of insertion holes.

[0061] Specifically, in the embodiment, four connecting holes are arranged at four corners of the fixed frame 11, and four lock bolts 2, i.e., a first lock bolt 21, a second lock bolt 22, a third lock bolt 23 and a fourth lock bolt 24, are used to pass through the four connecting holes and screw with four nuts to fix the fixed frame 11 and the supporting frame 12.

[0062] Further, the supporting frame 12 is provided with a through hole through which the beam 52 passes. During installation, the beam 52 can be penetrated from the spherical end of the beam 52 through the through hole on the supporting frame 12, the supporting frame 12 is arranged below the square ring 51, and then the fixed frame 11 is buckled on the supporting frame 12 from above the square ring 51. Then, the fixed frame 11 and the supporting frame 12 are connected and fixed by screwing the lock bolts 2 with the nuts.

[0063] Preferably, a positioning hole can also be formed on the supporting beam 53, and a positioning column 13 matched with the positioning hole is arranged on the end face of the fixed frame 11 and the supporting frame 12 at the same time when buckling, as shown in Figures 6-7 During installation, the positioning column 13 on the fixed frame 11 and the supporting frame 12 can be inserted into the positioning hole formed on the supporting beam 53, so as to facilitate the installation and positioning of the fixed box 1 and the square ring 51.

[0064] The supporting frame 6 is fixedly arranged on the supporting frame 12, and is provided with a plurality of supporting legs 61 for supporting the ground. The plurality of supporting legs 61 cooperate with the beam 52 to form a multi-point supporting mode to ensure the stability of the entire piezoelectric robot on the plane. In the embodiment, the number of the supporting legs 61 is two, and each supporting leg 61 is provided with a rotatable passive wheel 7.

[0065] That is, the spherical end of the beam 52 serves as the active foot of the entire piezoelectric robot, and the passive wheel 7 arranged on the supporting leg 61 serves as the passive foot of the entire piezoelectric robot. When the auxiliary supporting mechanism is arranged on the base body 5, the beam 52 needs to be arranged at an angle with the ground to prevent the robot from overturning due to the shift of the center of gravity, and facilitate the movement by generating friction with the ground through vibration. When the plurality of passive feet provide support for the single beam 52 and also ensure that the beam 52 drives the entire piezoelectric robot to move, the friction of the supporting leg 61 on the ground is reduced.

[0066] Secondly, the application further provides a motion excitation method of the piezoelectric robot, which is used for controlling the piezoelectric robot to perform linear motion on the ground and rotational motion around an axis perpendicular to the ground, that is, the piezoelectric robot has a two-degree-of-freedom motion state, and the method comprises the following contents:

[0067] A global coordinate system O-XYZ is set for the whole piezoelectric robot, as shown in the figure, Figure 8 Wherein:

[0068] The spherical end of the beam 52 is taken as the global coordinate origin O;

[0069] The plane formed by the X axis and the Z axis is taken as the ground, and the downward direction perpendicular to the ground is taken as the positive direction of the Y axis, and vice versa;

[0070] The direction in which the fourth locking bolt 24 points to the second locking bolt 22 is taken as the positive direction of the Z axis, and vice versa;

[0071] The direction in which the third locking bolt 23 points to the first locking bolt 21 is taken as the positive direction of the X axis, and vice versa;

[0072] In order to facilitate the description of the vibration behavior of the base body 5, a global coordinate system o-xyz is set for the base body 5, as shown in the figure, Figure 9 Wherein:

[0073] The spherical end of the beam 52 is taken as the origin o of the global coordinate system;

[0074] The downward direction perpendicular to the upper surface of the square ring 51 is taken as the positive direction of the y axis, and vice versa;

[0075] The direction in which the third rectangular piezoelectric ceramic sheet 43 points to the first rectangular piezoelectric ceramic sheet 41 is taken as the positive direction of the x axis, and vice versa;

[0076] The direction in which the fourth rectangular piezoelectric ceramic sheet 44 points to the second rectangular piezoelectric ceramic sheet 42 is taken as the positive direction of the z axis, and vice versa;

[0077] In order to further represent the driving mechanism of the whole piezoelectric robot, a local coordinate system o1-x1y1z1 is set in the base body 5, as shown in the figure, Figure 9 Wherein:

[0078] The positive direction of the y1 axis is consistent with the positive direction of the y axis, the positive direction of the x1 axis is the combined direction of the positive direction of the x axis and the positive direction of the z axis, and the positive direction of the z1 axis is the combined direction of the negative direction of the x axis and the positive direction of the z axis;

[0079] The polarization direction of the four rectangular piezoelectric ceramic sheets 4 is set to be inwardly perpendicular to the pasting surface of the beam 52, and the polarization direction of the annular piezoelectric ceramic sheet 8 is set to be inwardly perpendicular to the pasting surface of the square ring 51.

[0080] Then, the second rectangular piezoelectric sheet 42 and the fourth rectangular piezoelectric sheet 44 corresponding to the four rectangular piezoelectric sheets 4 are applied with a first excitation signal;

[0081] The first rectangular piezoelectric sheet 41 and the third rectangular piezoelectric sheet 43 corresponding to the four rectangular piezoelectric sheets 4 are applied with a second excitation signal;

[0082] The annular piezoelectric sheet 8 is applied with a third excitation signal;

[0083] The first excitation signal, the second excitation signal and the third excitation signal are all sine alternating voltage signals of the same frequency and amplitude;

[0084] That is, the two-degree-of-freedom motion of the piezoelectric robot on the ground can be realized by controlling the first excitation signal, the second excitation signal and the third excitation signal;

[0085] Further, when it is needed to control the piezoelectric robot to move along the positive direction of the Z axis, the second excitation signal lags behind the first excitation signal by one quarter of a period in time phase, and the third excitation signal leads the first excitation signal by one quarter of a period in time phase;

[0086] Specifically, under the action of the above excitation signals, the base body 5 generates a vibration mode characterized by bending of the spherical tip along the x direction, a vibration mode characterized by bending along the z direction, and a vibration mode characterized by stretching along the y direction. Based on the coupling mechanism of the vibration modes and the setting of the phase of the excitation signals, the vibration of the spherical tip along the x and z directions is coupled into vibration along the z1 direction, and the vibration of the spherical tip along the y direction is consistent with its vibration along the y1 direction. These vibrations ultimately synthesize a counterclockwise elliptical trajectory in the plane o1-y1z1. By utilizing the frictional force given to the spherical tip by the ground, the entire piezoelectric robot can realize linear motion along the positive direction of the Z axis;

[0087] When it is needed to control the piezoelectric robot to move along the negative direction of the Z axis, the second excitation signal lags behind the first excitation signal by one quarter of a period in time phase, and the third excitation signal lags behind the first excitation signal by one quarter of a period in time phase;

[0088] Similarly, under the action of the above excitation signals, the spherical tip of the base body 5 generates a clockwise elliptical trajectory in the plane o1-y1z1, thereby driving the piezoelectric robot to move along the negative direction of the Z axis;

[0089] When it is needed to control the piezoelectric robot to rotate clockwise around the Y axis, the second excitation signal is in phase with the first excitation signal in time phase, and the third excitation signal leads the first excitation signal by one quarter of a period in time phase;

[0090] Under the action of the excitation signals, the base 5 generates a vibration mode characterized by bending of the spherical tip along the x direction, a vibration mode characterized by bending along the z direction, and a vibration mode characterized by stretching along the y direction. Based on the coupling mechanism of the vibration modes and the setting of the phases of the excitation signals, the vibrations of the spherical tip along the x and z directions are coupled into a vibration along the x1 direction, the vibration of the spherical tip along the y direction is consistent with the vibration thereof along the y1 direction, and these vibrations are ultimately combined into a clockwise elliptical trajectory in the plane o1-x1y1; by using the frictional force given to the spherical tip by the ground, the piezoelectric robot can realize clockwise rotation movement about the Y axis.

[0091] When it is necessary to control the piezoelectric robot to rotate counterclockwise about the Y axis, the second excitation signal is in phase with the first excitation signal in the time phase, and the third excitation signal lags behind the first excitation signal by one quarter of a period in the time phase, the spherical tip of the base 5 generates a counterclockwise elliptical trajectory in the plane o1-x1y1, thereby driving the piezoelectric robot to realize counterclockwise rotation movement about the Y axis.

[0092] Finally, the above description is only used to explain the principles of the present application and cannot be interpreted in any way as a limitation on the scope of protection of the present application. Based on the explanation herein, those skilled in the art can conceive other specific embodiments of the present application without creative labor, and these embodiments will fall within the scope of protection of the present application.

Claims

1. A piezoelectric robot based on a ring-beam combination structure, comprising a base (5) and a piezoelectric element fixedly arranged on the base (5); It is characterized in that The base (5) comprises a square ring (51) and a beam (52) fixedly arranged at the center of the square ring (51); the square ring (51) is in a square shape, and a support beam (53) is fixedly arranged inside the square ring; one end of the beam (52) is fixedly connected to the center of the support beam (53) through a transition beam (54); the other end of the beam (52) is a spherical end; The piezoelectric element comprises four rectangular piezoelectric sheets (4) and an annular piezoelectric sheet (8), wherein the four rectangular piezoelectric sheets (4) are evenly distributed on the side surface of the beam (52) along the circumference of the beam (52), and the annular piezoelectric sheet (8) has the same shape as the square ring (51) and is fixedly arranged on the end surface of the square ring (51) away from the beam (52); An auxiliary support mechanism is provided on the outside of the square ring (51), and the auxiliary support mechanism is provided with a plurality of support legs (61) for supporting the ground. The support legs (61) are each provided with a rotatable passive wheel (7), and the spherical ends of the plurality of passive wheels (7) and the beam (52) respectively form the passive foot and the active foot of the piezoelectric robot.

2. A piezoelectric robot based on a ring-beam combination structure according to claim 1, characterized in that: The side surface of the beam (52) is rectangular.

3. A piezoelectric robot based on a ring-beam combination structure according to claim 2, characterized in that: The support beam (53) is in a cross shape or a cross shape.

4. The piezoelectric robot based on the ring-beam combination structure according to claim 3, characterized in that: The base (5) is formed in an integrated manner.

5. The piezoelectric robot based on the ring-beam combination structure according to claim 1, characterized in that: The piezoelectric element is piezoelectric ceramic or piezoelectric polymer.

6. The piezoelectric robot based on a ring-beam combination structure according to claim 1, characterized in that: The auxiliary support structure comprises: a fixed box body (1) and a support frame (6) fixedly arranged on the fixed box body (1); The fixed box (1) comprises a fixed frame (11) and a supporting frame (12), and the fixed frame (11) and the supporting frame (12) are fastened to the outside of the square ring (51) by means of bolt connection; The support frame (6) is fixedly arranged on the support frame (12), and the plurality of support legs are fixedly arranged on the support frame (6).

7. A method for exciting in-plane two-degree-of-freedom motion of a piezoelectric robot based on a ring-beam combination structure according to any one of claims 1 to 6, characterized in that: Includes the following: First, set the global coordinate system O-XYZ for the entire piezoelectric robot, where: The spherical end of the beam (52) is taken as the origin O of the global coordinate system; The plane formed by the X-axis and the Z-axis is the ground, the downward direction perpendicular to the ground is the positive direction of the Y-axis, and the opposite is the negative direction of the Y-axis; The direction in which the fourth locking bolt (24) points toward the second locking bolt (22) is the positive direction of the Z axis, and the opposite direction is the negative direction of the Z axis; The direction in which the third locking bolt (23) points toward the first locking bolt (21) is the positive direction of the X-axis, and the opposite direction is the negative direction of the X-axis; The global coordinate system o-xyz is set for the base (5), where: The spherical end of the beam (52) is taken as the origin o of the global coordinate system; The downward direction perpendicular to the upper surface of the square ring (51) is the positive direction of the y-axis, and the reverse direction is the negative direction of the y-axis; The direction from the third rectangular piezoelectric sheet (43) to the first rectangular piezoelectric sheet (41) is the positive direction of the x-axis, and the opposite direction is the negative direction of the x-axis; The direction from the fourth rectangular piezoelectric ceramic piece (44) to the second rectangular piezoelectric piece (42) is the positive direction of the z-axis, and the opposite direction is the negative direction of the z-axis; Set the local coordinate system o1-x1y1z1 in the matrix (5), where: The positive direction of the y1-axis is consistent with the positive direction of the y-axis, the positive direction of the x1-axis is the combined direction of the positive direction of the x-axis and the positive direction of the z-axis, and the positive direction of the z1-axis is the combined direction of the negative direction of the x-axis and the positive direction of the z-axis; Secondly, the polarization directions of the third rectangular piezoelectric piece (43) and the fourth rectangular piezoelectric piece (44) of the four rectangular piezoelectric pieces (4) are set to be perpendicular to the side of the beam (52) and facing inward, and the polarization directions of the first rectangular piezoelectric piece (41) and the second rectangular piezoelectric piece (42) are set to be perpendicular to the side of the beam (52) and facing outward; The polarization direction of the annular piezoelectric piece (8) is set to be perpendicular to the surface of the square ring (51) and inward; Applying a first excitation signal to a second rectangular piezoelectric piece (42) and a fourth piezoelectric piece (44) that are correspondingly arranged among the four rectangular piezoelectric pieces (4); Applying a second excitation signal to a first rectangular piezoelectric piece (41) and a third rectangular piezoelectric piece (43) corresponding to the four rectangular piezoelectric pieces (4); Applying a third excitation signal to the annular piezoelectric piece (8); The first excitation signal, the second excitation signal, and the third excitation signal are all sinusoidal AC voltage signals with the same frequency and amplitude.

8. The method for exciting the in-plane two-degree-of-freedom motion of a piezoelectric robot based on a ring-beam combination structure according to claim 7, characterized in that: When the piezoelectric robot needs to be controlled to move linearly along the positive Z-axis: the second excitation signal is delayed by half a cycle of the first excitation signal in time phase, and the third excitation signal is advanced by a quarter of a cycle of the first excitation signal; When the piezoelectric robot needs to be controlled to move linearly along the negative Z-axis: the second excitation signal is delayed by half a cycle of the first excitation signal in time phase, and the third excitation signal is delayed by a quarter of a cycle of the first excitation signal.

9. The method for exciting the in-plane two-degree-of-freedom motion of a piezoelectric robot based on a ring-beam combination structure according to claim 7, characterized in that: When the piezoelectric robot needs to be controlled to rotate clockwise along the Y axis: the second excitation signal is in phase with the first excitation signal in terms of time phase, and the third excitation signal is ahead of the first excitation signal in terms of time phase by a quarter of a cycle; When the piezoelectric robot needs to be controlled to rotate counterclockwise along the Y axis: the second excitation signal is made in phase with the first excitation signal in terms of time phase, and the third excitation signal lags the first excitation signal by a quarter of a cycle in terms of time phase.

Images