A multi-legged decoupled piezoelectric robot based on a multi-stage flexible structure and a multi-degree-of-freedom motion excitation method

Abstract

The application discloses a multi-legged decoupling piezoelectric robot in the field of small robots and a multi-degree-of-freedom excitation method thereof. The structure comprises multiple groups of same piezoelectric driving units, counterweight masses and connecting thin beams. The piezoelectric driving unit comprises a driving leg and a piezoelectric composite beam, and the piezoelectric composite beam generates bending vibration when a voltage signal is applied, a two-dimensional vibration track is synthesized at the driving leg, and then driving force is obtained by utilizing the friction coupling effect between the driving leg and the ground, so that relative movement between the driving leg and the ground is generated; by cooperation of the connecting thin beam and the counterweight mass, vibration isolation and decoupling of adjacent piezoelectric composite beams are realized, and vibration tracks of each driving leg are independently controlled. By applying periodic excitation signals with different amplitudes, the driving leg generates vibration tracks with different amplitudes and different directions, and multi-directional movement of the robot is realized. The piezoelectric robot has the advantages of simple structure, easy miniaturization and light weight, flexible movement and high displacement resolution, and has wide application prospects in the field of high-efficiency and precision operation in a wide range.

Description

Technical Field

[0001] This invention belongs to the field of small robot technology, specifically designing a multi-legged decoupled piezoelectric robot with a multi-level flexible structure and a multi-degree-of-freedom motion excitation method. Background Technology

[0002] Robotics technology is hailed as the "crown jewel of manufacturing," and micro-robots have become a hot research area in recent years. Their small size, light weight, and flexible movement allow them to be applied in numerous fields such as bioengineering, reconnaissance, energy detection, and micromanipulation. Traditional micro-robots often use electromagnetic motors for propulsion, which facilitates rapid movement; however, their transmission mechanisms can lead to complex structures and limited resolution. Reducing the size of components like coils and magnets results in torque dissipation, limiting the application of electromagnetic motor robots in confined spaces. In contrast, novel driving methods utilizing the inverse piezoelectric effect of piezoelectric ceramics exhibit superior characteristics such as high resolution, fast response speed, and no electromagnetic interference, which are beneficial for improving the speed, displacement resolution, and response time of micro-robots. Thanks to the excellent characteristics of piezoelectric drive technology, micro-robots based on piezoelectric drives have gained significant attention and research from scholars in recent years.

[0003] This invention proposes a small, multi-legged, decoupled piezoelectric robot. Its basic structure consists of multiple piezoelectric drive units arranged horizontally in parallel. A multi-level flexible structure composed of counterweights and connecting thin beams serves as the vibration isolation method between the piezoelectric drive units. This vibration isolation between the multiple piezoelectric drive units achieves decoupling and independent control of the vibration trajectories of the multiple drive legs, thereby enabling flexible planar motion of the robot. First, this small, multi-legged piezoelectric robot features a parallel mechanism, offering significant advantages in terms of large load capacity and high displacement resolution. Second, the piezoelectric drive units used are simple, compact, lightweight, small in size, and easy to manufacture and assemble. Third, the multi-level flexible structure arrangement achieves vibration isolation and decoupling between the multiple piezoelectric drive units. Finally, a multi-degree-of-freedom excitation method for this small, multi-legged piezoelectric robot is proposed. Two periodic excitation signals are used to excite each piezoelectric drive unit to obtain a two-dimensional vibration trajectory at the end of its drive leg. The friction between the drive leg and the ground serves as the driving force, and the coordinated operation of the two-dimensional vibration trajectories of the multiple drive legs enables the robot's planar multi-degree-of-freedom motion. In summary, the small multi-legged decoupled piezoelectric robot of the present invention has the advantages of simple structure, light weight and fast response of general small piezoelectric robots, while overcoming the problem of vibration coupling between multiple piezoelectric drive units. It realizes the balance of multi-degree-of-freedom motion, high speed and high displacement resolution of piezoelectric robots, greatly expanding its application range and making the small multi-legged decoupled piezoelectric robot have broad application prospects in the fields of precision handling, detection and precision driving and positioning. Summary of the Invention

[0004] To address the problem of poor motion flexibility caused by vibration coupling between multiple piezoelectric drive units in existing resonant small piezoelectric robots, this invention proposes a multi-legged decoupled piezoelectric robot with a multi-level flexible structure and its multi-degree-of-freedom excitation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention proposes a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. The robot includes multiple sets of slender piezoelectric drive units, multiple counterweight blocks, and multiple connecting thin beams.

[0007] The connecting thin beams include short connecting thin beams and long connecting thin beams;

[0008] The piezoelectric drive unit is connected to the counterweight mass blocks via short connecting thin beams, while the counterweight mass blocks are connected to each other via long connecting thin beams.

[0009] Each set of piezoelectric drive units has the same structure, and each set of piezoelectric drive units includes a drive foot and a piezoelectric composite beam.

[0010] A drive foot is fixedly connected to the outer end of each piezoelectric composite beam;

[0011] When the piezoelectric ceramics in the two orthogonal directions of the piezoelectric composite beam are excited by a voltage signal, they vibrate in two directions respectively, enabling the drive foot to achieve "horizontal swing" and "vertical lifting" actions.

[0012] Vibration isolation and decoupling between adjacent piezoelectric drive units are achieved through multi-level combinations of thin-walled beams and counterweight mass blocks, thereby enabling independent control of vibration trajectories at multiple drive feet.

[0013] Furthermore, each set of piezoelectric drive units has the same structure, and the drive feet and piezoelectric composite beams included therein are symmetrical structures in two orthogonal directions. The symmetrical structure is a square cross-section or a circular cross-section.

[0014] Furthermore, the piezoelectric composite beam is composed of a piezoelectric matrix beam, OZ-oriented piezoelectric ceramics, and OX-oriented piezoelectric ceramics;

[0015] Two OZ-oriented piezoelectric ceramics and two OX-oriented piezoelectric ceramics are respectively attached to the four sides of the piezoelectric matrix beam, and the same type of piezoelectric ceramics are attached to the same opposite sides.

[0016] The piezoelectric composite beam has a patch-type structure, and the polarization direction of the two piezoelectric ceramics is in the thickness direction.

[0017] Furthermore, the piezoelectric drive units are connected by a multi-level flexible structure consisting of counterweights and connecting thin beams, with the connection points being the vibration nodes of the piezoelectric composite beams; the number of counterweights is not less than 1, and the number of connecting thin beams is not less than 2, with the two arranged alternately; the connection method is bonding, bolting, or direct processing into a single piece.

[0018] Furthermore, the number of the four piezoelectric drive units in the multi-legged decoupled piezoelectric robot based on a multi-level flexible structure can be three, five, or six. When the number is three, the three piezoelectric drive units are arranged at equal intervals along the circumference with an interval angle of 120°. When the number is four, the four piezoelectric drive units are arranged in parallel, with two on each side. When the number is five, the five piezoelectric drive units are arranged at equal intervals along the circumference with an interval angle of 72°. When the number is six, the six piezoelectric drive units are arranged in parallel, with three on each side.

[0019] This invention also provides a two-dimensional vibration trajectory excitation method for the driving feet of a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. The excitation method generates a two-dimensional vibration trajectory at each driving foot by exciting the bending vibration of each group of piezoelectric driving units in two orthogonal directions, OZ and OX. Taking a group of piezoelectric driving units as an example, an excitation voltage is applied to the piezoelectric ceramics in the OZ direction and the piezoelectric ceramics in the OX direction, respectively, so that the piezoelectric composite beam generates bending vibration modes along the OZ and OX directions, thereby causing the driving foot to produce "horizontal swing" and "vertical lifting" actions, respectively. By setting the phase difference between the two sets of excitation signals, the driving foot generates a two-dimensional vibration trajectory.

[0020] Furthermore, the bending vibration mode of the piezoelectric composite beam is a first-order or second-order bending vibration mode; the phase difference between the two excitation signals is 0-360 degrees, and the direction change of the driving two-dimensional vibration trajectory is realized by exchanging the order of the two excitation signals.

[0021] Furthermore, the waveform of the excitation signal required to realize the excitation method for driving the two-dimensional vibration trajectory of the foot is a high-frequency periodic signal, the signal frequency is the resonant frequency of the piezoelectric composite beam, and the signal waveform is a sine wave, square wave, or trapezoidal wave. The amplitude of the two-dimensional vibration trajectory of the foot is changed by changing the voltage amplitude of the excitation signal.

[0022] The present invention also provides a multi-degree-of-freedom excitation method for a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. By planning the excitation signals of multiple sets of piezoelectric drive units, the coordinated operation of the two-dimensional vibration trajectories of multiple drive legs is realized, thereby achieving multi-degree-of-freedom planar motion of the robot, including linear, turning and rotational motion.

[0023] This will be illustrated using a quadrupedal decoupled piezoelectric robot as an example;

[0024] In the aforementioned planar motion, the excitation method for the quadrupedal decoupled piezoelectric robot to achieve linear motion is as follows:

[0025] By applying identical two-way excitation signals to four sets of piezoelectric drive units, the four drive feet generate the same two-dimensional vibration trajectory, thereby realizing the robot's linear motion. By exchanging the phase difference between the two-way excitation signals and changing the direction of the two-dimensional vibration trajectory of the drive feet, the robot's reverse linear motion can be achieved.

[0026] In the aforementioned planar motion, the excitation method for the quadrupedal decoupled piezoelectric robot to achieve steering motion is as follows:

[0027] Two identical excitation signals I and II are applied to the two sets of piezoelectric drive units in the positive Y-axis direction, and two identical additional excitation signals III and IV are applied to the two sets of piezoelectric drive units in the negative Y-axis direction. By setting the voltage amplitude of excitation signals I and II to be greater than that of excitation signals III and IV, the amplitude of the positive Y-axis drive foot is made greater than that of the negative Y-axis drive foot, thereby enabling the robot to achieve a turning motion biased towards the negative Y-axis direction. By setting the voltage amplitude of excitation signals I and II to be less than that of excitation signals III and IV, the amplitude of the positive Y-axis drive foot is made less than that of the negative Y-axis drive foot, thereby enabling the robot to achieve a turning motion biased towards the positive Y-axis direction.

[0028] In the aforementioned planar motion, the excitation method for the quadrupedal decoupled piezoelectric robot to achieve rotational motion is as follows:

[0029] The same two excitation signals I and II are applied to the two sets of piezoelectric drive units in the positive Y-axis direction, and the same other two excitation signals III and IV are applied to the two sets of piezoelectric drive units in the negative Y-axis direction. By setting the voltage amplitude of the four excitation signals to be the same, and the phase difference between excitation signals I and II being opposite to the phase difference between excitation signals III and IV, the vibration trajectories of the four drive feet are made to have the same amplitude but opposite directions, thereby realizing the rotational motion of the robot around the Z-axis.

[0030] Furthermore, the multi-degree-of-freedom excitation method can achieve independent control of the amplitude and direction of the two-dimensional vibration trajectory of multiple driving feet through active control 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 robot's multi-degree-of-freedom motion.

[0031] The beneficial effects of this invention are as follows:

[0032] 1. This invention provides a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure, which has the characteristics of simple structure, small size and light weight. Vibration decoupling between multiple piezoelectric drive units is achieved through the vibration isolation design of the multi-level flexible structure.

[0033] 2. The present invention provides a multi-degree-of-freedom excitation method for a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. This method can excite multiple piezoelectric drive units to vibrate in coordination, so that different drive legs generate vibration trajectories with desired directions and amplitudes. This enables small, multi-group decoupled piezoelectric robots to perform linear, turning, and rotational movements, achieving planar multi-free motion capability. This greatly improves the motion flexibility of resonant piezoelectric robots, expands their application range, and has broad application prospects in fields such as large-scale precision handling and positioning detection. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a three-dimensional structural schematic diagram of the quadrupedal decoupled small piezoelectric robot proposed in this invention;

[0036] Figure 2 This is a schematic diagram of the structure of a single piezoelectric drive unit according to the present invention;

[0037] Figure 3 This is a schematic diagram of the two-dimensional vibration trajectory of the driven foot and the corresponding excitation scheme described in this invention;

[0038] Figure 4 This is a schematic diagram of the linear motion and excitation scheme of the quadrupedal decoupled small piezoelectric robot described in this invention.

[0039] Figure 5 This is a schematic diagram of the steering motion and excitation scheme of the quadrupedal decoupled small piezoelectric robot described in this invention.

[0040] Figure 6 This is a schematic diagram of the rotational motion and excitation scheme of the quadrupedal decoupled small piezoelectric robot described in this invention.

[0041] Figure 7 This is a schematic diagram of the three-legged decoupled small piezoelectric robot structure described in this invention;

[0042] Figure 8 This is a schematic diagram of the five-legged decoupled small piezoelectric robot structure described in this invention;

[0043] Figure 9 This is a schematic diagram of the six-legged decoupled small piezoelectric robot structure described in this invention.

[0044] Wherein, 1 represents a slender piezoelectric drive unit, 1-1 represents the first group of piezoelectric drive units, 1-1-1 represents the first drive foot, 1-1-2 represents a piezoelectric composite beam, 1-1-2-1 represents a piezoelectric matrix beam, 1-1-2-2 represents an OZ-oriented piezoelectric ceramic, 1-1-2-3 represents an OX-oriented piezoelectric ceramic, 1-2 represents the second group of piezoelectric drive units, 1-2-1 represents the second drive foot, 1-3 represents the third group of piezoelectric drive units, 1-3-1 represents the third drive foot, 1-4 represents the fourth group of piezoelectric drive units, 1-4-1 represents the fourth drive foot, 1-5 represents the fifth group of piezoelectric drive units, 1-5-1 represents the fifth drive foot, 1-6 represents the sixth group of piezoelectric drive units, 1-6-1 represents the sixth drive foot, 2 represents a counterweight mass block, 3 represents a connecting thin beam, 3-2 represents a short connecting thin beam, and 3-1 represents a long connecting thin beam. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0046] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Specific implementation method one:

[0048] Combination Figure 1 This embodiment describes a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. The robot includes multiple sets of slender piezoelectric drive units 1, multiple counterweight blocks 2, and multiple connecting thin beams 3.

[0049] like Figure 1 As shown, taking four sets of piezoelectric drive units 1 as an example, the four sets of piezoelectric drive units 1 include a first set of piezoelectric drive units 1-1, a second set of piezoelectric drive units 1-2, a third set of piezoelectric drive units 1-3 and a fourth set of piezoelectric drive units 1-4.

[0050] The connecting thin beam 3 includes a short connecting thin beam 3-2 and a long connecting thin beam 3-1; the piezoelectric drive unit 1 is connected to the counterweight mass block 2 through the short connecting thin beam 3-2, while each counterweight mass block 2 is connected to the other through the long connecting thin beam 3-1.

[0051] The four sets of piezoelectric drive units have the same structure, and each set of piezoelectric drive units includes a drive foot 1-1-1 and a piezoelectric composite beam 1-1-2.

[0052] A driving foot 1-1-1 is fixedly connected to the outer end of each piezoelectric composite beam 1-1-2;

[0053] When the piezoelectric ceramics in the two orthogonal directions of the piezoelectric composite beam are excited by a voltage signal, they vibrate in two directions respectively, enabling the drive foot to achieve horizontal swinging and vertical lifting movements.

[0054] Vibration isolation and decoupling between adjacent piezoelectric drive units 1 are achieved through multi-level combination of connecting thin beam 3 and counterweight mass block 2, thereby realizing independent control of vibration trajectory at multiple drive feet.

[0055] The small, multi-legged, decoupled piezoelectric robot proposed in this embodiment excites the piezoelectric ceramics in two orthogonal directions of the piezoelectric composite beam with voltage signals, causing vibrations in two directions respectively. This enables the drive legs to perform horizontal swinging and vertical lifting actions. It features simple structure, small size, and light weight. At the same time, the vibration decoupling between multiple piezoelectric drive units is achieved through the vibration isolation design of a multi-level flexible structure. Specific Implementation Method Two:

[0057] Combination Figure 2 This embodiment is a further detailed description of the multi-legged decoupled piezoelectric robot based on a multi-level flexible structure described in Embodiment 1 above.

[0058] Each set of piezoelectric drive units has the same structure. The drive foot 1-1-1 and the piezoelectric composite beam 1-1-2 are symmetrical in two orthogonal directions. The symmetrical structure is a square cross section or a circular cross section.

[0059] like Figure 2 As shown, a driving foot 1-1-1 is fixedly connected to the outer end of each piezoelectric composite beam 1-1-2;

[0060] The piezoelectric composite beam 1-1-2 includes a piezoelectric matrix beam 1-1-2-1, an OZ-oriented piezoelectric ceramic 1-1-2-2, and an OX-oriented piezoelectric ceramic 1-1-2-3;

[0061] Two OZ-oriented piezoelectric ceramics 1-1-2-2 and two OX-oriented piezoelectric ceramics 1-1-2-3 are respectively attached to the four sides of the piezoelectric substrate beam 1-1-2-1, and the same type of piezoelectric ceramics are attached to the same opposite sides.

[0062] The piezoelectric drive units 1 are connected by a multi-level flexible structure consisting of counterweights and connecting thin beams, with the connection position being the vibration node position of the piezoelectric composite beam; the number of counterweights 2 is not less than 1, and the number of connecting thin beams 3 is not less than 2, and the two are arranged alternately; the connection method is bonding, bolting, or direct processing into a single piece.

[0063] Furthermore, the number of the four piezoelectric drive units in the small multi-legged decoupled piezoelectric robot can be three, five, or six. When the number is three, the three piezoelectric drive units are arranged at equal intervals along the circumference with an interval angle of 120°. When the number is five, the five piezoelectric drive units are arranged at equal intervals along the circumference with an interval angle of 72°. When the number is six, the six piezoelectric drive units are arranged in parallel, three on each of the left and right sides. Specific implementation method three:

[0065] Combination Figure 3 This embodiment describes a method for exciting the two-dimensional vibration trajectory of the driving legs of a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. Figure 3 As shown, the excitation method generates a two-dimensional vibration trajectory at each driving foot by exciting each group of piezoelectric driving units to bend and vibrate in two orthogonal directions, OZ and OX; taking a group of piezoelectric driving units as an example, as... Figure 3 As shown, an excitation voltage is applied to the OZ-direction piezoelectric ceramic and the OX-direction piezoelectric ceramic assembly, respectively, causing the piezoelectric composite beam to generate bending vibration modes along the OZ and OX directions, respectively, which in turn causes the driving foot to generate "horizontal swing" and "vertical lifting" actions, respectively; by setting the phase difference between the two sets of excitation signals, the driving foot generates a two-dimensional vibration trajectory.

[0066] Furthermore, the bending vibration mode of the piezoelectric composite beam (1-1-2) is a first-order or second-order bending vibration mode; the phase difference between the two excitation signals is 0-360 degrees, and the direction of the driving two-dimensional vibration trajectory is realized by exchanging the order of the two excitation signals.

[0067] Furthermore, the waveform of the excitation signal required to realize the excitation method for driving the two-dimensional vibration trajectory of the foot is a high-frequency periodic signal, the signal frequency is the resonant frequency of the piezoelectric composite beam, and the signal waveform is a sine wave, square wave, or trapezoidal wave. The amplitude of the two-dimensional vibration trajectory of the foot is changed by changing the voltage amplitude of the excitation signal. Specific implementation method four:

[0069] Combination Figures 4 to 6 This embodiment describes a multi-degree-of-freedom excitation method for a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. By planning the excitation signals of multiple sets of piezoelectric drive units, the coordinated operation of the two-dimensional vibration trajectories of multiple drive legs is achieved, thereby realizing the robot's planar multi-degree-of-freedom motion, including linear, turning, and rotational motion.

[0070] This will be illustrated using a quadrupedal decoupled piezoelectric robot as an example;

[0071] In the aforementioned planar motion, an excitation method for the linear motion of a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure is described below:

[0072] like Figure 4 As shown, identical two-way excitation signals are applied to four sets of piezoelectric drive units 1-1, 1-2, 1-3 and 1-4, causing the four drive feet to generate the same two-dimensional vibration trajectory, thereby realizing the robot's linear motion; by exchanging the phase difference between the two-way excitation signals, the direction of the two-dimensional vibration trajectory of the drive feet can be changed, and the robot's reverse linear motion can be realized.

[0073] In the aforementioned planar motion, an excitation method for the steering motion of a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure is described below:

[0074] like Figure 5 As shown, the same two excitation signals I and II are applied to the two sets of piezoelectric drive units 1-1 and 1-2 in the positive Y-axis direction, and the same other two excitation signals III and IV are applied to the two sets of piezoelectric drive units 1-3 and 1-4 in the negative Y-axis direction. By setting the voltage amplitude of excitation signals I and II to be greater than that of excitation signals III and IV, the amplitude of the positive Y-axis drive feet 1-1-1 and 1-2-1 is made greater than that of the negative Y-axis drive feet 1-3-1 and 1-4-1, thereby enabling the robot to achieve a turning motion biased towards the negative Y-axis direction. By setting the voltage amplitude of excitation signals I and II to be less than that of excitation signals III and IV, the amplitude of the positive Y-axis drive feet 1-1-1 and 1-2-1 is made less than that of the negative Y-axis drive feet 1-3-1 and 1-4-1, thereby enabling the robot to achieve a turning motion biased towards the positive Y-axis direction.

[0075] In the aforementioned planar motion, an excitation method for the rotational motion of a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure is described below:

[0076] like Figure 6 As shown, the same two excitation signals I and II are applied to the two sets of piezoelectric drive units 1-1 and 1-2 in the positive Y-axis direction, and the same other two excitation signals III and IV are applied to the two sets of piezoelectric drive units 1-3 and 1-4 in the negative Y-axis direction. By setting the voltage amplitude of the four excitation signals to be the same, and the phase difference between excitation signals I and II being opposite to the phase difference between excitation signals III and IV, the vibration trajectories of the four drive feet are made to have the same amplitude but opposite directions, thereby realizing the rotational motion of the robot around the Z-axis.

[0077] Furthermore, the multi-degree-of-freedom excitation method can achieve independent control of the amplitude and direction of the two-dimensional vibration trajectory of multiple driving feet through active control 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 robot's multi-degree-of-freedom motion.

[0078] In summary, this embodiment provides a multi-degree-of-freedom excitation method for a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure. This method can excite multiple piezoelectric drive units to vibrate in a coordinated manner, causing different drive legs to generate vibration trajectories with desired directions and amplitudes. This enables small, multi-group decoupled piezoelectric robots to achieve linear, turning, and rotational movements, obtaining planar multi-free motion capabilities. It greatly improves the motion flexibility of resonant piezoelectric robots, expands their application range, and has broad application prospects in fields such as large-scale precision handling and positioning detection. Specific implementation method five:

[0080] Combination Figure 7 This embodiment differs from the multi-legged decoupled piezoelectric robot based on a multi-level flexible structure described in Embodiment 1 in that the robot consists of three piezoelectric drive units, which are arranged at equal intervals along the circumference with an angle of 120°. By applying periodic excitation signals of different amplitudes, the drive legs of the three piezoelectric drive units can be excited to generate vibration trajectories of different amplitudes and directions, thereby achieving planar three-degree-of-freedom motion of the robot through the coordinated cooperation of the three drive legs.

[0081] The specific excitation method for the linear motion of the three-legged decoupled piezoelectric robot is as follows:

[0082] When two piezoelectric drive units 1-1 and 1-2 are applied with excitation voltage signals of the same amplitude and phase difference, the two corresponding drive feet 1-1-1 and 1-2-1 generate two-dimensional vibration trajectories of the same amplitude, both of which are biased towards R3. Under the action of the resultant force, they generate linear motion along the direction of R3.

[0083] The specific excitation method for the steering motion of the three-legged decoupled piezoelectric robot is as follows:

[0084] When excitation voltage signals with different amplitudes but the same phase difference are applied to two piezoelectric drive units 1-1 and 1-2, the corresponding two drive feet 1-1-1 and 1-2-1 generate two-dimensional vibration trajectories with different amplitudes, both of which are biased towards R3. Under the action of the resultant force, they generate a turning motion that deviates from the direction of R3.

[0085] The specific excitation method for the rotational motion of the three-legged decoupled piezoelectric robot is as follows:

[0086] When excitation voltage signals with the same amplitude but different phase differences are applied to three piezoelectric drive units 1-1, 1-2 and 1-3, the three corresponding drive feet 1-1-1, 1-2-1 and 1-3-1 generate two-dimensional vibration trajectories with the same amplitude, but in different directions, and generate rotational motion around the Z-axis under the action of the resultant force. Specific implementation method six:

[0088] Combination Figure 8 This embodiment differs from the multi-legged decoupled piezoelectric robot based on a multi-level flexible structure described in Embodiment 1 in that the robot consists of five piezoelectric drive units, which are arranged at equal intervals along the circumference with an angle of 72°. By applying periodic excitation signals of different amplitudes, the drive legs of the five piezoelectric drive units can be excited to generate vibration trajectories of different amplitudes and directions, thereby achieving planar three-degree-of-freedom motion of the robot through the coordinated cooperation of the five drive legs.

[0089] The specific excitation method for the linear motion of the five-legged decoupled piezoelectric robot is as follows:

[0090] When excitation voltage signals with the same amplitude and phase difference are applied to four piezoelectric drive units 1-1, 1-2, 1-3 and 1-4, the corresponding four drive feet 1-1-1, 1-2-1, 1-3-1 and 1-4-1 generate two-dimensional vibration trajectories with the same amplitude, all of which are biased towards R5. Under the action of the resultant force, they generate linear motion along the R5 direction.

[0091] The specific excitation method for the steering motion of the five-legged decoupled piezoelectric robot is as follows:

[0092] When excitation voltage signals with different amplitudes but the same phase difference are applied to four piezoelectric drive units 1-1, 1-2, 1-3 and 1-4, the four corresponding drive feet 1-1-1, 1-2-1, 1-3-1 and 1-4-1 generate two-dimensional vibration trajectories with different amplitudes, all of which are biased towards R3. Under the action of the resultant force, they generate a turning motion that deviates from the direction of R3.

[0093] The specific excitation method for the rotational motion of the five-legged decoupled piezoelectric robot is as follows:

[0094] When excitation voltage signals with the same amplitude but different phase differences are applied to five piezoelectric drive units 1-1, 1-2, 1-3, 1-4 and 1-5, the corresponding five drive feet 1-1-1, 1-2-1, 1-3-1, 1-4-1 and 1-5-1 generate two-dimensional vibration trajectories with the same amplitude, but in different directions, and generate rotational motion around the Z-axis under the action of the resultant force. Specific implementation method seven:

[0096] Combination Figure 9This embodiment differs from the multi-legged decoupled piezoelectric robot based on a multi-level flexible structure described in Embodiment 1 in that the robot consists of six piezoelectric drive units arranged in parallel, three on each side. By applying periodic excitation signals of different amplitudes, the drive legs of the six piezoelectric drive units can be excited to produce vibration trajectories of different amplitudes and directions, thereby achieving planar three-degree-of-freedom motion of the robot through the coordinated cooperation of the six drive legs.

[0097] The specific excitation method for the linear motion of the hexapod decoupled piezoelectric robot is as follows:

[0098] When excitation voltage signals with the same amplitude and phase difference are applied to six piezoelectric drive units 1-1, 1-2, 1-3, 1-4, 1-5 and 1-6, the corresponding six drive feet 1-1-1, 1-2-1, 1-3-1, 1-4-1, 1-5-1 and 1-6-1 all generate two-dimensional vibration trajectories with the same amplitude and the same direction, and under the action of the resultant force, they generate linear motion along the X direction.

[0099] The specific excitation method for the steering motion of the hexapod decoupled piezoelectric robot is as follows:

[0100] Excitation voltage signals with different amplitudes but the same phase difference are applied to six piezoelectric drive units 1-1, 1-2, 1-3, 1-4, 1-5 and 1-6. The excitation voltage amplitudes of piezoelectric drive units 1-1, 1-3 and 1-5 are the same, and the excitation voltage amplitudes of piezoelectric drive units 1-2, 1-4 and 1-6 are the same. The corresponding left drive feet 1-1-1, 1-3-1 and 1-5-1 produce two-dimensional vibration trajectories with the same amplitude, and the right drive feet 1-2-1, 1-4-1 and 1-6-1 also produce two-dimensional vibration trajectories with the same amplitude. The vibration trajectories of the drive feet on both sides are in the same direction, but the vibration amplitudes are different. Under the action of the resultant force, they produce a turning motion that deviates from the X direction.

[0101] The specific excitation method for the rotational motion of the hexapod decoupled piezoelectric robot is as follows:

[0102] Excitation voltage signals with the same amplitude but different phase differences are applied to six piezoelectric drive units 1-1, 1-2, 1-3, 1-4, 1-5 and 1-6. The phase differences of the excitation voltages of piezoelectric drive units 1-1, 1-3 and 1-5 are the same, and the phase differences of the excitation voltages of piezoelectric drive units 1-2, 1-4 and 1-6 are the same. The corresponding left drive feet 1-1-1, 1-3-1 and 1-5-1 generate two-dimensional vibration trajectories in the same direction, and the right drive feet 1-2-1, 1-4-1 and 1-6-1 also generate two-dimensional vibration trajectories in the same direction. The amplitudes of the vibration trajectories of the two drive feet are the same, but the directions of the vibration trajectories are opposite. Under the action of the resultant force, they generate rotational motion around the Z-axis.

[0103] In summary, this embodiment can adjust the number of piezoelectric drive units as needed based on actual working conditions. By applying periodic excitation signals of different amplitudes, the drive legs of different numbers of piezoelectric drive units can be excited to produce vibration trajectories of different amplitudes and directions. In turn, the coordinated operation of the drive legs enables the robot to achieve planar three-degree-of-freedom motion.

[0104] The foregoing has provided a detailed description of the multi-legged decoupled piezoelectric robot based on a multi-level flexible structure and its multi-degree-of-freedom motion excitation method proposed in this invention. The principles and implementation methods of this invention have been explained. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A multi-legged decoupled piezoelectric robot based on a multi-level flexible structure, characterized in that, The robot includes multiple sets of slender piezoelectric drive units (1), multiple counterweights (2), and multiple connecting thin beams (3). The connecting thin beam (3) includes a short connecting thin beam (3-2) and a long connecting thin beam (3-1); The piezoelectric drive unit (1) is connected to the counterweight mass block (2) through a short connecting thin beam (3-2), while each counterweight mass block (2) is connected to the other through a long connecting thin beam (3-1); Each group of piezoelectric drive units has the same structure, and each group of piezoelectric drive units includes a drive foot (1-1-1) and a piezoelectric composite beam (1-1-2). A driving foot (1-1-1) is fixedly connected to the outer end of each piezoelectric composite beam (1-1-2). When the piezoelectric ceramics in the two orthogonal directions of the piezoelectric composite beam are excited by a voltage signal, they vibrate in two directions respectively, enabling the drive foot to achieve horizontal swinging and vertical lifting movements. Vibration isolation and decoupling between adjacent piezoelectric drive units (1) are achieved by multi-level combination of connecting thin beam (3) and counterweight mass block (2), thereby realizing independent control of vibration trajectory at multiple drive feet.

2. The multi-legged decoupled piezoelectric robot based on a multi-level flexible structure according to claim 1, characterized in that, Each piezoelectric drive unit (1) includes a drive foot (1-1-1) and a piezoelectric composite beam (1-1-2) which are symmetrical in two orthogonal directions. The symmetrical structure is a square cross section or a circular cross section.

3. The multi-legged decoupled piezoelectric robot based on a multi-level flexible structure according to claim 1, characterized in that, The piezoelectric composite beam (1-1-2) includes a piezoelectric matrix beam (1-1-2-1), an OZ-oriented piezoelectric ceramic (1-1-2-2), and an OX-oriented piezoelectric ceramic (1-1-2-3). Two OZ-oriented piezoelectric ceramics (1-1-2-2) and two OX-oriented piezoelectric ceramics (1-1-2-3) are respectively attached to the four sides of the piezoelectric matrix beam (1-1-2-1), and piezoelectric ceramics with the same polarization direction are attached to the same opposite side; The polarization direction of each piezoelectric ceramic is along its thickness direction.

4. The multi-legged decoupled piezoelectric robot based on a multi-level flexible structure according to claim 1, characterized in that, Each group of piezoelectric drive units is connected by a multi-level flexible structure consisting of a counterweight mass block (2) and a connecting thin beam (3), and the connection position is the vibration node position of the piezoelectric composite beam; The number of counterweight mass blocks (2) is not less than 1, the number of connecting thin beams (3) is not less than 2, and the two are arranged alternately.

5. A multi-legged decoupled piezoelectric robot based on a multi-level flexible structure according to claim 1, characterized in that, The number of piezoelectric drive units (1) is 3, 5 or 6; When the quantity is 3, the 3 piezoelectric drive units are arranged at equal intervals along the circumference, with an interval angle of 120°. When the quantity is 5, the 5 piezoelectric drive units are arranged at equal intervals along the circumference, with an interval angle of 72°. When the quantity is 6, the 6 piezoelectric drive units are arranged in parallel, with three on each side.

6. A method for exciting the two-dimensional vibration trajectory of the driving legs of a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure as described in any one of claims 1-5, characterized in that, This excitation method generates a two-dimensional vibration trajectory at each drive foot by exciting each group of piezoelectric drive units to bend in two orthogonal directions, OZ and OX.

7. The method for driving a two-dimensional vibration trajectory excitation of a foot according to claim 6, characterized in that, The bending vibration mode of the piezoelectric composite beam is a first-order or second-order bending vibration mode; the phase difference between the two excitation signals is 0-360 degrees, and the direction change of the driving two-dimensional vibration trajectory is achieved by exchanging the order of the two excitation signals.

8. The method for driving a two-dimensional vibration trajectory excitation of a foot according to claim 6, characterized in that, The waveform of the excitation voltage signal required to implement this method is a high-frequency periodic signal with a signal frequency equal to the resonant frequency of the piezoelectric composite beam. The signal waveform can be a sine wave, a square wave, or a trapezoidal wave. The amplitude of the two-dimensional vibration trajectory of the driven foot is changed by altering the voltage amplitude of the excitation signal.

9. A multi-degree-of-freedom excitation method for a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure as described in any one of claims 1-5, characterized in that, By planning the excitation signals of multiple sets of piezoelectric drive units, the coordinated operation of multiple two-dimensional vibration trajectories of the drive feet is achieved, thereby realizing multi-degree-of-freedom planar motion of the robot, including linear, turning and rotational motion. Excitation methods for linear motion of quadrupedal decoupled piezoelectric robots: By applying identical two-way excitation signals to four sets of piezoelectric drive units, the four drive feet generate the same two-dimensional vibration trajectory, thereby realizing the robot's linear motion; by exchanging the phase difference between the two-way excitation signals, the direction of the two-dimensional vibration trajectory of the drive feet is changed, thereby realizing the robot's reverse linear motion. Excitation methods for the steering motion of a quadrupedal decoupled piezoelectric robot: Two identical excitation signals I and II are applied to the two sets of piezoelectric drive units in the positive Y-axis direction, and two identical additional excitation signals III and IV are applied to the two sets of piezoelectric drive units in the negative Y-axis direction. By setting the voltage amplitude of excitation signals I and II to be greater than that of excitation signals III and IV, the amplitude of the positive Y-axis drive foot is made greater than that of the negative Y-axis drive foot, thereby enabling the robot to achieve a turning motion biased towards the negative Y-axis direction. By setting the voltage amplitude of excitation signals I and II to be less than that of excitation signals III and IV, the amplitude of the positive Y-axis drive foot is made less than that of the negative Y-axis drive foot, thereby enabling the robot to achieve a turning motion biased towards the positive Y-axis direction. Excitation methods for the rotational motion of a quadrupedal decoupled piezoelectric robot: The same two excitation signals I and II are applied to the two sets of piezoelectric drive units in the positive Y-axis direction, and the same other two excitation signals III and IV are applied to the two sets of piezoelectric drive units in the negative Y-axis direction. By setting the voltage amplitude of the four excitation signals to be the same, and the phase difference between excitation signals I and II being opposite to the phase difference between excitation signals III and IV, the vibration trajectories of the four drive feet are made to have the same amplitude but opposite directions, thereby realizing the rotational motion of the robot around the Z-axis.

10. The multi-degree-of-freedom excitation method for a multi-legged decoupled piezoelectric robot based on a multi-level flexible structure according to claim 9, characterized in that, By actively regulating the excitation signal, the amplitude and direction of the two-dimensional vibration trajectory of multiple driving feet can be independently controlled, adjusting the magnitude and direction of the friction force between the driving feet and the ground, thereby enabling flexible switching of the robot's multi-degree-of-freedom motion.

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