Small piezoelectric robot supported by foot wheels in matched mode and multi-degree-of-freedom motion excitation method of small piezoelectric robot

Abstract

The invention discloses a small piezoelectric robot supported by foot wheels in a matched mode and a multi-degree-of-freedom motion excitation method of the small piezoelectric robot, and belongs to the field of small robots. The device is composed of two sets of same piezoelectric composite beams, balancing weights, driving feet, connecting structures, roller supports and rollers. The piezoelectric composite beam is of a symmetrical structure in the orthogonal direction, and the included angle between the two orthogonal directions and the ground is 45 degrees. When excitation voltage signals are applied, the piezoelectric composite beam bends and vibrates in the orthogonal direction, then an oblique line vibration track is generated, driving force is obtained through friction coupling, and relative movement with the ground is achieved. The two piezoelectric composite beams are connected through the connecting structures, the roller supports are fixedly connected with the rollers and the connecting structures, and the driving feet and the rollers are matched to stably support the robot. Different excitation signals are applied to the two groups of piezoelectric composite beams, the vibration tracks of the driving feet are different, and the robot can move linearly, steer and rotate through coordination. And the device has the advantages of miniaturization, movement flexibility, high displacement resolution, strong load capacity and wide application prospect in the field of heavy-load precision operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of small robots, and particularly designs a small piezoelectric robot supported by a combination of foot wheels and a multi-degree-of-freedom motion excitation method thereof Background Art

[0002] Benefiting from characteristics such as small size, light weight, and flexible movement, micro-small robots have become one of the popular research and development directions in the field of robotics in recent years, and can be applied to many fields such as bioengineering, military reconnaissance, energy exploration, and micro-operation. Traditional micro-small robots mostly use electromagnetic motors for driving, and such micro-small robots are easy to achieve fast movement; however, their transmission mechanisms are likely to lead to complex structures and limited resolution, and the reduction of the sizes of components such as coils and magnets will result in torque dissipation, limiting the micro-operation applications of electromagnetic motor robots in narrow ranges. In contrast, a new driving method that utilizes the inverse piezoelectric effect of piezoelectric ceramics exhibits excellent characteristics such as high resolution, fast response speed, and no electromagnetic interference, which is beneficial to improving the characteristics of micro-small robots such as speed, displacement resolution, and response time; due to the excellent characteristics of piezoelectric driving technology, micro-small robots based on piezoelectric driving have received the favor and research of many scholars in recent years.

[0003] Existing resonant small piezoelectric robots mostly achieve flexible movement through the cooperation of multiple patch-type piezoelectric actuation units. However, their stiffness is relatively low and the load-bearing capacity is limited. Sandwich-type piezoelectric actuation units with greater structural stiffness can be used to improve the load capacity of the robot, but vibration coupling is prone to occur between high-stiffness piezoelectric actuation units, resulting in poor movement flexibility of the robot. In view of the problem of the contradiction between high movement flexibility and large load capacity of existing resonant small piezoelectric robots, the present invention proposes a small piezoelectric robot with wheel-leg cooperation for support. With two piezoelectric actuation units arranged horizontally side by side and the center of the roller placed in front as the basic structural form, the vibration of the piezoelectric actuation unit generates a driving force by obtaining the vibration trajectory of the foot end. The roller is used for auxiliary support to improve the load capacity. The multi-degree-of-freedom movement in the plane of the robot is achieved by regulating the amplitude difference between the two piezoelectric actuation units. First, the small robot improves the load capacity of the robot by combining an active driving foot and a passive supporting roller. Second, the piezoelectric driving unit adopted has a simple and compact structure, is light in weight, easy to process and assemble, and is set at an angle of 45° between its side and the ground. Finally, a multi-degree-of-freedom excitation method for the wheel-leg cooperation type small piezoelectric robot is proposed. Thanks to the 45° angle arrangement between the piezoelectric driving unit and the ground, a periodic excitation signal is used to respectively excite two pairs of piezoelectric ceramics of the piezoelectric driving unit, and oblique vibration trajectories in the positive and negative 45-degree directions can be obtained at the driving foot end respectively. The friction force between it and the ground is used as the driving force, and then the multi-degree-of-freedom movement in the plane of the robot is achieved by regulating the amplitudes of the oblique vibration trajectories of the two driving feet. Generally speaking, the wheel-leg cooperation type small piezoelectric robot of the present invention has the advantages of simple structure, light weight, fast response, etc. of general small piezoelectric robots, solves the problem of the contradiction between high movement flexibility and large load capacity, realizes the balance of multi-degree-of-freedom movement, large load capacity, fast speed and high displacement resolution of the piezoelectric robot, greatly expands its application range, and makes the wheel-leg cooperation type small piezoelectric robot have broad application prospects in the fields of precision handling, detection, precision driving and positioning, etc. Summary of the Invention

[0004] In order to solve the problem of the contradiction between high movement flexibility and large load capacity of existing resonant small piezoelectric robots, the present invention proposes a small piezoelectric robot with wheel-leg cooperation for support and a multi-degree-of-freedom movement excitation method therefor.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention proposes a small piezoelectric robot with wheel-leg cooperation for support, and the small piezoelectric robot includes a piezoelectric driving unit, a counterweight unit, a driving foot unit, a connection structure unit, a roller bracket and a roller;

[0007] The piezoelectric drive unit includes a first piezoelectric composite beam and a second piezoelectric composite beam; the counterweight unit includes a first counterweight and a second counterweight; the drive foot unit includes a first drive foot and a second drive foot; the connection structure unit includes a first connection structure and a second connection structure;

[0008] The cross-section centerlines of the two groups of piezoelectric composite beams, the two groups of counterweights, and the two groups of drive feet are collinear, and they are symmetric structures in two orthogonal directions;

[0009] The two groups of piezoelectric composite beams are used to generate bending vibrations along two orthogonal directions respectively under the excitation of voltage signals with specific frequencies;

[0010] The two groups of drive feet are respectively connected to the outer ends of the two groups of piezoelectric composite beams, and are used to generate diagonal vibration trajectories in two corresponding directions as the two groups of piezoelectric composite beams bend, and then obtain the driving force of the drive feet relative to the ground by using the friction coupling effect, so that relative movement is generated between it and the ground;

[0011] The two groups of counterweights are respectively fixedly connected to the other sides of the two groups of piezoelectric composite beams, and are used to adjust the node positions of the bending vibrations of the two groups of piezoelectric composite beams, so that their vibration nodes coincide with the thin-walled beams, so that the bending vibrations of the two groups of piezoelectric composite beams are isolated, and then the decoupling and independent control of the vibration trajectories of the two groups of drive feet are realized;

[0012] The two groups of piezoelectric composite beams are connected through two groups of connection structure units, and the rollers and the connection structure units are fixedly connected through a roller bracket, and then the robot is stably supported through the cooperation of the rollers and the two groups of drive feet.

[0013] Further, the two groups of piezoelectric composite beam structures are completely the same, the two groups of counterweight structures are completely the same, and the two drive foot structures are completely the same; their cross-section centerlines are collinear, and they are symmetric structures in two orthogonal directions. The included angles between the two orthogonal directions and the ground horizontal direction are both 45 degrees. The symmetric structure is a square cross-section or a circular cross-section; the drive foot is a cross-shaped cross-section with four protrusions added on the basis of a square cross-section or a circular cross-section.

[0014] Further, the piezoelectric composite beam is composed of a slender beam, a pair of piezoelectric ceramics in the positive 45-degree direction, and a pair of piezoelectric ceramics in the negative 45-degree direction; the polarization directions of the two pairs of piezoelectric ceramics are all along their thickness directions, and the polarization directions of the two pairs of piezoelectric ceramics are the same; the piezoelectric ceramics and the slender beam are fixedly connected, and the fixed connection method can be pasting, interference fit or bolt and screw connection.

[0015] Furthermore, the above two groups of piezoelectric composite beams are fixedly connected by two groups of connection structures; the connection structure unit consists of a group of matrix beams and two groups of thin-walled beams, and the thin-walled beams are arranged vertically; the fixed connection method is bonding, interference fit, bolt connection or directly machining into an integral part.

[0016] Furthermore, the connection position between the above piezoelectric composite beam and the thin-walled beam is the node position of its bending vibration, and this vibration node position can be adjusted by the size and material parameters of the counterweight.

[0017] Furthermore, the cross-section of the above roller bracket is an L-shaped structure, one side of which is fixedly connected to the matrix beam, and the connection method is bonding or bolt connection; the other side places the roller through a slot, and the connection between the roller bracket and the roller is realized by shaft-hole fit.

[0018] Furthermore, the number of the above rollers can be 1, 2, 3 or 4; when the number of rollers is 2, each of the two matrix beams is provided with 1 roller and both are arranged in the middle; when the number is 3, the front matrix beam is provided with 1 roller in the middle, and each of the two ends of the rear matrix beam is provided with 1 roller; when the number is 4, each of the two ends of the two matrix beams is provided with 1 roller; the increase in the number of rollers can gradually improve the load capacity of the robot.

[0019] The present invention also provides a multi-degree-of-freedom motion excitation method applied to a small-wheeled cooperating piezoelectric robot. The excitation method respectively excites the bending vibration of the piezoelectric composite beam in the ±45-degree directions to generate diagonal vibration trajectories in the corresponding directions on the driving feet; by programming the excitation signals of the two groups of piezoelectric composite beams, the coordinated cooperation of the two driving feet is realized, and then the planar multi-degree-of-freedom motion of the robot is realized, including linear, steering and rotational motions;

[0020] Linear motion of the small-wheeled cooperating piezoelectric robot:

[0021] Apply the same excitation signal to the piezoelectric ceramics in the positive 45-degree direction of the two groups of piezoelectric composite beams, so that the two driving feet generate diagonal vibration trajectories along the positive 45-degree direction and with the same amplitude, and the two driving feet generate driving forces with the same direction and magnitude, thereby realizing the linear motion of the robot; apply the same excitation signal to the piezoelectric ceramics in the negative 45-degree direction, and the two driving feet can generate diagonal vibration trajectories along the negative 45-degree direction and with the same amplitude, thereby realizing the reverse linear motion of the robot;

[0022] Steering motion of the small-wheeled cooperating piezoelectric robot:

[0023] Apply excitation signals with different amplitudes to the 45-degree positive piezoelectric ceramics of two groups of piezoelectric composite beams, so that the two driving feet generate oblique vibration trajectories along the 45-degree positive direction but with different amplitudes. Driving forces with the same direction but different magnitudes are generated at the two driving feet, thereby driving the robot to generate a forward turning motion; when the amplitude of the excitation signal of one side of the piezoelectric composite beam is larger, the robot is driven to move forward to the left, and when the amplitude of the excitation signal of the other side of the piezoelectric composite beam is larger, the robot is driven to move forward to the right; similarly, by applying excitation signals with different amplitudes to the 45-degree negative piezoelectric ceramics of two groups of piezoelectric composite beams, the robot can be driven to generate a backward turning motion;

[0024] Rotational motion of the small wheel-matching piezoelectric robot:

[0025] Apply excitation signals with the same amplitude to the 45-degree positive piezoelectric ceramics of one group of piezoelectric composite beams and the 45-degree negative piezoelectric ceramics of another group of piezoelectric composite beams, so that the two driving feet generate oblique vibration trajectories with the same amplitude but along the positive and negative 45-degree directions respectively. Driving forces with the same magnitude but opposite directions are generated at the two driving feet, thereby driving the robot to generate a rotational motion; by applying excitation signals with the same amplitude to the other two pairs of piezoelectric ceramics, the reverse rotational motion of the robot can be achieved.

[0026] Furthermore, the bending vibration mode of the piezoelectric composite beam is the first-order, second-order or third-order bending vibration mode;

[0027] Furthermore, the waveform of the excitation voltage signal required to implement this method is a high-frequency periodic signal, the signal frequency is the resonance frequency of the bending vibration of the piezoelectric composite beam, the signal waveform is a sine signal, a square wave signal or a trapezoidal wave signal, and the amplitude of the oblique vibration trajectory of the driving foot is changed by changing the voltage amplitude of the excitation signal.

[0028] Furthermore, the multi-degree-of-freedom excitation method can independently control the amplitude and direction of the oblique vibration trajectories of the two driving feet through the active regulation of the excitation signal, adjust the magnitude and direction of the friction force between the driving feet and the ground, and thus realize the flexible switching of the multi-degree-of-freedom motion of the robot.

[0029] Advantages of the present invention:

[0030] 1. The present invention provides a small mobile piezoelectric robot, which has the characteristics of simple structure, small volume and light weight. The load capacity is greatly improved through the support design of wheel matching, and the independent regulation of the vibration trajectories of the two driving feet is realized through the design of connecting the vibration nodes with thin-walled beams;

[0031] 2. The small caster wheel - cooperative piezoelectric robot multi - degree - of - freedom excitation method provided by the present invention can excite the coordinated vibration of two piezoelectric composite beams, so that the two driving feet generate oblique vibration trajectories with the required directions and amplitudes, realizing the linear, turning and rotating motions of the small caster wheel - cooperative piezoelectric robot, obtaining the planar multi - degree - of - freedom motion ability; meanwhile, it realizes the large load - bearing capacity and high motion flexibility of the resonant small piezoelectric robot, expands its application range, and has broad application prospects in fields such as large - range precision handling and positioning detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 is a schematic structural diagram of the small caster wheel - cooperative piezoelectric robot proposed by the present invention;

[0034] Figure 2 is a schematic structural diagram of the roller bracket and the roller proposed by the present invention;

[0035] Figure 3 is a schematic structural diagram of the connection structure proposed by the present invention;

[0036] Figure 4 is a schematic diagram of the driving foot vibration trajectory and the corresponding excitation scheme of the small caster wheel - cooperative piezoelectric robot described in the present invention;

[0037] Figure 5 is a schematic diagram of the linear motion of the small caster wheel - cooperative piezoelectric robot described in the present invention and its excitation scheme;

[0038] Figure 6 is a schematic diagram of the turning motion of the small caster wheel - cooperative piezoelectric robot described in the present invention and its excitation scheme;

[0039] Figure 7 is a schematic diagram of the rotational motion of the small caster wheel - cooperative piezoelectric robot described in the present invention and its excitation scheme;

[0040] Figure 8 is a schematic structural diagram of the small caster wheel - cooperative piezoelectric robot based on double - roller support described in the present invention;

[0041] Figure 9 is a schematic structural diagram of the small caster wheel - cooperative piezoelectric robot based on triple - roller support described in the present invention;

[0042] Figure 10It is a schematic diagram of the structure of a small caster-wheel cooperative piezoelectric robot based on four-wheel support according to the present invention. Among them, 1 represents a piezoelectric driving unit, 1-1 represents a first piezoelectric composite beam, 2 represents a counterweight unit, 2-1 represents a first counterweight block, 2-2 represents a second counterweight block, 3 represents a driving caster unit, 3-1 represents a first driving caster, 3-2 represents a second driving caster, 4 represents a connection structure unit, 4-1 represents a first connection structure, 4-2 represents a second connection structure, 4-2-1 represents a base beam, 4-2-2 represents a first thin-walled beam, 4-2-3 represents a second thin-walled beam, 5 represents a caster bracket, 5-1 represents a first caster bracket, 5-1-1 represents a rolling shaft, 5-2 represents a second caster bracket, 5-3 represents a third caster bracket, 5-4 represents a fourth caster bracket, 6 represents a caster, 6-1 represents a first caster, 6-2 represents a second caster, 6-3 represents a third caster, and 6-4 represents a fourth caster. Detailed implementation manners

[0043] The following further elaborates on the detailed implementation manners of the present invention with reference to the accompanying drawings. The following implementation manners will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made, and these all fall within the protection scope of the present invention. Detailed implementation manner one:

[0045] Combined with Figure 1 To illustrate this implementation manner, this implementation manner proposes a small piezoelectric robot using caster-wheel cooperative support. The small piezoelectric robot includes a piezoelectric driving unit 1, a counterweight unit 2, a driving caster unit 3, a connection structure unit 4, a caster bracket 5, and a caster 6;

[0046] As Figure 1 shown, the piezoelectric driving unit 1 includes a first piezoelectric composite beam 1-1 and a second piezoelectric composite beam 1-2, and the structures of the two groups of piezoelectric composite beams are completely the same; the counterweight unit 2 includes a first counterweight block 2-1 and a second counterweight block 2-2, and the structures of the two groups of counterweight blocks are completely the same; the driving caster unit 3 includes a first driving caster 3-1 and a second driving caster 3-2, and the structures of the two groups of driving casters are completely the same; the connection structure unit 4 includes a first connection structure 4-1 and a second connection structure 4-2, and the structures of the two groups of connection structures are completely the same.

[0047] The two groups of piezoelectric composite beams are symmetric structures in orthogonal directions, and the included angles between the two orthogonal directions and the ground are both 45 degrees. When an excitation voltage signal is applied to the two groups of piezoelectric composite beams, they are respectively excited to generate bending vibrations along the two orthogonal directions. The driving feet are fixedly connected to the piezoelectric composite beams, and with the bending vibrations of the piezoelectric composite beams, they can generate diagonal vibration trajectories in two corresponding directions. Then, through the friction coupling effect, the driving force of the driving feet relative to the ground is obtained, causing relative movement between them and the ground.

[0048] The two groups of piezoelectric composite beams are respectively connected through two groups of connection structures. Each group of connection structures includes a base beam and two thin-walled beams. The two groups of mass blocks are respectively fixedly connected to the other sides of the two groups of piezoelectric composite beams, and are all used to adjust the node positions of the bending vibrations of the two groups of piezoelectric composite beams, so that their vibration nodes coincide with the thin-walled beams, isolating the bending vibrations of the two groups of piezoelectric composite beams, and then realizing the decoupling and independent control of the vibration trajectories of the two groups of driving feet. The roller 6 and the connection structure are fixedly connected through the roller bracket 5, and then the robot is stably supported through the roller 6 and the two driving feet. The way of wheel support is conducive to the robot to bear large loads. Specific Embodiment 2:

[0050] Combined with Figures 1 to 3 This embodiment is described. This embodiment specifically describes the structure of a small piezoelectric robot using wheel support proposed in the above Embodiment 1.

[0051] As Figure 1 shown, the two groups of piezoelectric composite beam structures are completely the same, the two groups of counterweight block structures are completely the same, and the two driving foot structures are completely the same. Their cross-section centerlines are collinear, and they are symmetric structures in two orthogonal directions. The included angles between the two orthogonal directions and the ground horizontal direction are both 45 degrees. The symmetric structure is a square cross-section or a circular cross-section. The driving foot is a cross-like cross-section with four protrusions added on the basis of a square cross-section or a circular cross-section.

[0052] As Figure 1 shown, each group of piezoelectric composite beams is composed of a slender beam, a pair of piezoelectric ceramics at +45 degrees, and a pair of piezoelectric ceramics at -45 degrees. The polarization directions of the two pairs of piezoelectric ceramics are all along their thickness directions, and the polarization directions of the two pairs of piezoelectric ceramics are the same. The piezoelectric ceramics and the slender beam are fixedly connected, and the fixed connection method can be pasting, interference fit or bolt and screw connection.

[0053] The two groups of piezoelectric composite beams are respectively fixedly connected by two groups of connection structures. The connection structure includes a group of base beams and two groups of thin-walled beams. The two groups of thin-walled beams are both fixed on the base beam in the vertical direction. Specifically, as Figure 3 shown, the first thin-walled beam 4-2-2 and the second thin-walled beam 4-2-3 are both fixed on the base beam 4-2-1 in the vertical direction.

[0054] The connection position between the piezoelectric composite beam and the thin-walled beam is the node position of its bending vibration, and this vibration node position can be adjusted by the size and material parameters of the counterweight block.

[0055] As Figure 2 shown, the cross-section of the roller bracket 5 is an L-shaped structure. One side of it is fixedly connected to the base beam, and the connection method is bonding or bolt connection; the other side places the roller 6 through the slot 5-1, and the connection between the roller bracket and the roller is realized by shaft-hole fit. Specifically: the roller 6 is provided with a hole diameter that realizes the connection with the two rolling shafts 5-1-1.

[0056] The number of the rollers can be 1, 2, 3 or 4; when the number of rollers is 2, each of the two base beams is provided with 1 roller and both are arranged in the middle; when the number is 3, the front base beam is provided with 1 roller in the middle, and each of the two ends of the rear base beam is provided with 1 roller; when the number is 4, each of the two ends of the two base beams is provided with 1 roller; the increase in the number of rollers can gradually improve the load capacity of the robot. Specific Embodiment 3:

[0058] Combined with Figure 4 and Figure 7 to illustrate this embodiment, this embodiment proposes a multi-degree-of-freedom motion excitation method applied to a small wheeled piezoelectric robot with cooperating wheels. As Figure 4 shown, the excitation method respectively excites the bending vibrations of the piezoelectric composite beam in the ±45-degree directions, generating diagonal vibration trajectories in the corresponding directions on the driving feet; by programming the excitation signals of the two groups of piezoelectric composite beams, the coordinated cooperation of the two driving feet is realized, and thus the planar multi-degree-of-freedom motion of the robot is achieved, including linear, steering and rotational motions;

[0059] As Figure 5 shown, the excitation method for the linear motion of the small wheeled piezoelectric robot with cooperating wheels is as follows:

[0060] Apply the same excitation signal to the piezoelectric ceramics in the positive 45-degree direction of the two groups of piezoelectric composite beams, so that the two driving feet generate diagonal vibration trajectories along the positive 45-degree direction and with the same amplitude, and the two driving feet generate driving forces with the same direction and magnitude, thus realizing the linear motion of the robot; apply the same excitation signal to the piezoelectric ceramics in the negative 45-degree direction, and the two driving feet can generate diagonal vibration trajectories along the negative 45-degree direction and with the same amplitude, thus realizing the reverse linear motion of the robot;

[0061] As Figure 6 shown, the excitation method for the steering motion of the small wheeled piezoelectric robot with cooperating wheels is as follows:

[0062] Apply excitation signals with different amplitudes to the +45° piezoelectric ceramics of two groups of piezoelectric composite beams, so that the two driving feet generate diagonal vibration trajectories along the +45° direction but with different amplitudes, and driving forces with the same direction but different magnitudes are generated at the two driving feet, thereby driving the robot to generate a forward turning motion; when the amplitude of the excitation signal of one side of the piezoelectric composite beam is larger, the robot is driven to move forward to the left, and when the amplitude of the excitation signal of the other side of the piezoelectric composite beam is larger, the robot is driven to move forward to the right; similarly, by applying excitation signals with different amplitudes to the -45° piezoelectric ceramics of two groups of piezoelectric composite beams, the robot can be driven to generate a backward turning motion;

[0063] As Figure 7 shown, the excitation method for the rotational motion of the small wheel - cooperating piezoelectric robot is as follows:

[0064] Apply excitation signals with the same amplitude to the +45° piezoelectric ceramics of one group of piezoelectric composite beams and the -45° piezoelectric ceramics of the other group of piezoelectric composite beams, so that the two driving feet generate diagonal vibration trajectories with the same amplitude but along the +45° and -45° directions respectively, and driving forces with the same magnitude but opposite directions are generated at the two driving feet, thereby driving the robot to generate a rotational motion; by applying excitation signals with the same amplitude to the other two pairs of piezoelectric ceramics, the reverse rotational motion of the robot can be achieved.

[0065] Furthermore, the bending vibration mode of the above - mentioned piezoelectric composite beam is the first - order, second - order or third - order bending vibration mode;

[0066] The waveform of the excitation voltage signal required to implement this method is a high - frequency periodic signal, the signal frequency is the resonant frequency of the bending vibration of the piezoelectric composite beam, the signal waveform is a sine signal, a square - wave signal or a trapezoidal - wave signal, and the amplitude of the diagonal vibration trajectory of the driving foot is changed by changing the voltage amplitude of the excitation signal.

[0067] The multi - degree - of - freedom excitation method can independently control the amplitude and direction of the diagonal vibration trajectories of the two driving feet through the active regulation of the excitation signal, adjust the magnitude and direction of the friction force between the driving feet and the ground, and thus realize the flexible switching of the multi - degree - of - freedom motion of the robot. Specific Embodiment 4:

[0069] Combined with Figures 8 to 10 to illustrate this embodiment, the small wheel - cooperating piezoelectric robot can also be provided with multiple support rollers, and the number of the rollers can be 1, 2, 3 or 4;

[0070] As Figure 8 shown, when the number of rollers is 2, each of the two base beams is provided with 1 roller bracket (5 - 1, 5 - 2) and rollers (6 - 1, 6 - 2), and they are both arranged in the middle.

[0071] AsFigure 9 As shown, when the number of rollers is 3, one roller bracket (5-1) and one roller (6-1) are centrally arranged on the front-side base beam, and one roller bracket (5-2, 5-3) and one roller (6-2, 6-3) are arranged at both ends of the rear-side base beam respectively;

[0072] As Figure 10 shown, when the number of rollers is 4, one roller bracket (5-1, 5-2, 5-3, 5-4) and one roller (6-1, 6-2, 6-3, 6-4) are arranged at both ends of the two base beams respectively; the increase in the number of rollers can gradually improve the load capacity of the robot.

[0073] Other compositions, connection relationships and excitation methods are the same as those in the above-mentioned specific embodiments 1 and 3.

[0074] The above has introduced in detail a small-footwheel cooperative support piezoelectric robot and its multi-degree-of-freedom motion excitation method proposed by the present invention, and has elaborated on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention: at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A small piezoelectric robot using wheel feet for cooperation and support, characterized in that, It includes a piezoelectric drive unit (1), a counterweight unit (2), a drive foot unit (3), a connection structure unit (4), a roller bracket (5) and rollers (6); The piezoelectric drive unit (1) includes a first piezoelectric composite beam (1-1) and a second piezoelectric composite beam (1-2); the counterweight unit (2) includes a first counterweight block (2-1) and a second counterweight block (2-2); the drive foot unit (3) includes a first drive foot (3-1) and a second drive foot (3-2); the connection structure unit (4) includes a first connection structure (4-1) and a second connection structure (4-2); The cross-section centerlines of the two groups of piezoelectric composite beams, the two groups of counterweight blocks and the two groups of drive feet are collinear, and they are symmetric structures in two orthogonal directions; The two groups of piezoelectric composite beams generate bending vibrations along two orthogonal directions respectively under the excitation of a voltage signal with a specific frequency; The two groups of drive feet are respectively connected to the outer ends of the two groups of piezoelectric composite beams, and are used to generate diagonal vibration trajectories in two corresponding directions with the bending vibrations of the two groups of piezoelectric composite beams, and then obtain the driving force of the drive feet relative to the ground by using the friction coupling effect, so that relative movement is generated between it and the ground; The two groups of counterweight blocks are respectively fixedly connected to the other sides of the two groups of piezoelectric composite beams, and are used to adjust the node positions of the bending vibrations of the two groups of piezoelectric composite beams, so that their vibration nodes coincide with the thin-walled beams, so that the bending vibrations of the two groups of piezoelectric composite beams are isolated, and then the decoupling and independent controllability of the vibration trajectories of the two groups of drive feet are realized; The two groups of piezoelectric composite beams are connected through two groups of connection structure units, and the rollers (6) and the connection structure unit are fixedly connected through the roller bracket (5), and then the robot is stably supported through the cooperation of the rollers and the two groups of drive feet.

2. The small piezoelectric robot using a foot wheel for cooperation in support according to claim 1, wherein The two groups of piezoelectric composite beams have the same structure, and the two groups of counterweight blocks have the same structure; the two groups of drive feet have the same structure; The included angles between the two orthogonal directions and the ground horizontal direction are both 45 degrees; The symmetric structure is a square cross-section or a circular cross-section; The drive foot is a cross-shaped cross-section with four protrusions added on the basis of a square cross-section or a circular cross-section.

3. A small piezoelectric robot using wheel feet for cooperation in support according to claim 1, characterized in that, Each group of piezoelectric composite beams is composed of a pair of piezoelectric ceramics at +45 degrees and a pair of piezoelectric ceramics at -45 degrees pasted on a slender beam; The polarization directions of the two pairs of piezoelectric ceramics are all along their thickness directions, and the polarization directions of the two pairs of piezoelectric ceramics are the same.

4. A small piezoelectric robot using a foot wheel for cooperation and support according to claim 1, characterized in that, The two groups of piezoelectric composite beams are respectively fixedly connected by two groups of connection structures; The connection structure unit includes a group of base beams and two groups of thin-walled beams, and the two groups of thin-walled beams are both fixed on the base beam in the vertical direction.

5. A small piezoelectric robot using a foot wheel for cooperation and support according to claim 4, wherein The connection position between the piezoelectric composite beam and the thin-walled beam is the node position of its bending vibration, and this vibration node position can be adjusted by the size and material parameters of the counterweight block.

6. A small piezoelectric robot using wheel feet for cooperation in support, characterized in that, The cross-section of the roller bracket (5) is an L-shaped structure; One side of the roller bracket (5) is fixedly connected to the base beam, and the other side places the roller (6) through a slot, and the connection between the roller bracket and the roller is realized by shaft-hole fit.

7. A small piezoelectric robot using a foot wheel for cooperation and support according to claim 6, characterized in that, The number of the rollers (6) is 1, 2, 3 or 4; When the number is 2, each of the two groups of base beams is provided with 1 roller, and they are both arranged in the middle; When the number is 3, one roller is centrally arranged on the front base beam, and one roller is arranged at each end of the rear base beam; When the number is 4, one roller is arranged at each end of the two groups of base beams.

8. A multi-degree-of-freedom motion excitation method implemented by a small piezoelectric robot using foot wheels for cooperation and support, characterized in that, This excitation method respectively excites the bending vibration of the piezoelectric composite beam in the ±45-degree directions, generating diagonal vibration trajectories in the corresponding directions at the driving feet; by programming the excitation signals of the two groups of piezoelectric composite beams, the coordinated cooperation of the two driving feet is realized, and then the planar multi-degree-of-freedom motion of the robot is realized, including linear, steering and rotational motions; Linear motion excitation method: Apply the same excitation signal to the +45-degree piezoelectric ceramics of the two groups of piezoelectric composite beams, so that the two driving feet generate diagonal vibration trajectories along the +45-degree direction and with the same amplitude, and the two driving feet generate driving forces with the same direction and magnitude, thereby realizing the linear motion of the robot; apply the same excitation signal to the -45-degree piezoelectric ceramics, and the two driving feet can generate diagonal vibration trajectories along the -45-degree direction and with the same amplitude, thereby realizing the reverse linear motion of the robot; Steering motion excitation method: Apply excitation signals with different amplitudes to the +45-degree piezoelectric ceramics of the two groups of piezoelectric composite beams, so that the two driving feet generate diagonal vibration trajectories along the +45-degree direction but with different amplitudes, and driving forces with the same direction but different magnitudes are generated at the two driving feet, thereby driving the robot to generate a forward steering motion; when the amplitude of the excitation signal of one side of the piezoelectric composite beam is larger, the robot is driven to move forward to the left, and when the amplitude of the excitation signal of the other side of the piezoelectric composite beam is larger, the robot is driven to move forward to the right; by applying excitation signals with different amplitudes to the -45-degree piezoelectric ceramics of the two groups of piezoelectric composite beams, the robot can be driven to generate a backward steering motion; Rotational motion excitation method: Apply excitation signals with the same amplitude to the +45-degree piezoelectric ceramics of one group of piezoelectric composite beams and the -45-degree piezoelectric ceramics of the other group of piezoelectric composite beams, so that the two driving feet generate diagonal vibration trajectories with the same amplitude but along the positive and negative 45-degree directions respectively, and driving forces with the same magnitude but opposite directions are generated at the two driving feet, thereby driving the robot to generate a rotational motion; apply excitation signals with the same amplitude to the other two pairs of piezoelectric ceramics to realize the reverse rotational motion of the robot.

9. The multi-degree-of-freedom motion excitation method for a small caster wheel cooperating with a supporting piezoelectric robot according to claim 8, characterized in that The bending vibration mode of the piezoelectric composite beam is the first-order, second-order or third-order bending vibration mode.

10. The multi-degree-of-freedom motion excitation method for a small caster wheel cooperating with a piezoelectric robot according to claim 8, characterized in that, This multi-degree-of-freedom excitation method realizes the independent regulation of the amplitude and direction of the diagonal vibration trajectories of the two driving feet through the active regulation of the excitation signals, adjusts the magnitude and direction of the friction force between the driving feet and the ground, and then realizes the flexible switching of the multi-degree-of-freedom motion of the robot.

Images