Piezoelectric actuator and robot

Abstract

This invention discloses a piezoelectric actuator and a robot, relating to the field of piezoelectric actuator technology. The piezoelectric actuator includes a stator, a connecting assembly, and a rotor. The stator includes a vibrating body and a first driving foot and a second driving foot respectively disposed on the vibrating body. A piezoelectric ceramic component is disposed on the periphery of the vibrating body, and the vibrating body also has a connecting rod. The connecting assembly includes a connector and a receiving member connected to each other. The connector is connected to the connecting rod, and the receiving member forms a receiving groove with a through hole at the bottom. The rotor is spherical and rotatably mounted in the receiving groove. The first driving foot is used to drive the rotor to rotate. This piezoelectric actuator effectively amplifies the displacement output of the vibrating body and significantly improves the moving speed and load capacity of the piezoelectric actuator, and can achieve multi-degree-of-freedom motion.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric actuator technology, and particularly to a piezoelectric actuator and robot. Background Technology

[0002] Piezoelectric actuators rely on the inverse piezoelectric effect to convert electrical energy into mechanical energy, and then use friction to achieve actuation, making them a type of special driving element. Compared to conventional motors and electromagnetic drive devices, these actuators have a simpler and more compact overall structure, faster response speed, can maintain a self-locking state after power failure, and are free from electromagnetic radiation interference, resulting in outstanding overall performance advantages.

[0003] Existing piezoelectric actuators generally utilize stick-slip and inchworm actuation mechanisms. Due to the small vibration displacement and poor mechanical output characteristics of the piezoelectric ceramics themselves, the thrust density and power density are limited, resulting in low moving speed and poor load-bearing capacity. This makes it impossible to meet the requirements of high speed and high load-bearing characteristics in practical applications, which is not conducive to the widespread application of actuators in multiple scenarios.

[0004] Therefore, it is necessary to provide a new piezoelectric actuator and robot to solve the above-mentioned technical problems. Summary of the Invention

[0005] The main objective of this invention is to propose a piezoelectric actuator and robot, which aims to improve the technical problems of poor load capacity and low degree of freedom of existing piezoelectric actuators.

[0006] To achieve the above objectives, according to some embodiments of the present invention, a piezoelectric actuator is provided, comprising: The stator includes a vibrating body and a first driving foot and a second driving foot respectively disposed on the vibrating body. A piezoelectric ceramic component is disposed on the outer periphery of the vibrating body, and the vibrating body is also provided with a connecting rod. A connecting assembly, comprising a connector and a receiving member connected to each other, the connector being connected to the connecting rod, the receiving member forming a receiving groove, and a through hole being provided at the bottom of the receiving groove; The rotor is spherical in shape and is rotatably mounted in the receiving groove. The first driving foot is used to drive the rotor to rotate.

[0007] In some embodiments, the receiving member is a hemispherical shell, the bottom of the hemispherical shell is provided with the through hole, the rotor portion extends out of the opening at the top of the hemispherical shell, the inner wall portion of the hemispherical shell extends outward to form a mounting groove, a ball bearing is provided in the mounting groove, and the ball bearing abuts against the rotor.

[0008] In some embodiments, the mounting groove has a step at its opening, and the ball bearing includes a body, an abutment plate disposed on the body, and a ball bearing. The body is disposed in the mounting groove, the abutment plate abuts against the step, the ball bearing partially protrudes from the abutment plate and is rotatably mounted on the abutment plate, and the ball bearing is rotatably connected to the rotor.

[0009] In some embodiments, a gap is formed between the abutment plate and the inner wall surface of the hemispherical shell, and the ball bearing further includes an elastic element, the two ends of which are respectively connected to the body and the ball.

[0010] In some embodiments, there are multiple mounting slots, which are distributed circumferentially on the hemispherical shell, and a ball bearing is correspondingly disposed in each mounting slot.

[0011] In some embodiments, the vibrator includes a rectangular component and a first hollow frame and a second hollow frame disposed at both ends of the rectangular component along a first direction. The first hollow frame is provided with the first driving foot, and the second hollow frame is provided with the second driving foot. The piezoelectric ceramic component includes four piezoelectric ceramic sheets, which are arranged to form a hollow square frame. The four piezoelectric ceramic sheets are attached to the four sides of the rectangular component one by one. The connecting rod is disposed on the rectangular component.

[0012] In some embodiments, the number of piezoelectric ceramic elements is two, the two piezoelectric ceramic elements are spaced apart from the rectangular element, and the connecting rod is disposed between the two piezoelectric ceramic elements.

[0013] In some embodiments, the connecting rod extends through the rectangular member along the second direction to form two connecting ends. The connecting member includes a base plate and two side plates respectively disposed on opposite sides of the base plate. The base plate is connected to the receiving member. The two side plates are disposed on opposite sides of the rectangular member along the second direction. The two side plates are connected to the two connecting ends one-to-one. The first direction is perpendicular to the second direction.

[0014] In some embodiments, the number of the first driving feet is two; And / or, the position where the first driving foot abuts against the rotor is set to a rounded head; And / or, the number of the second driving feet is two; And / or, the end of the second driving foot away from the vibrator is configured as a round head.

[0015] According to some embodiments of this application, this application also provides a robot, the robot including any of the piezoelectric actuators described above.

[0016] In the above scheme, the piezoelectric actuator includes a stator, a connecting assembly, and a rotor. The stator includes a vibrating body and a first driving foot and a second driving foot respectively disposed on the vibrating body. A piezoelectric ceramic component is disposed on the periphery of the vibrating body, and the vibrating body also has a connecting rod. The connecting assembly includes a connector and a receiving component connected to each other. The connector is connected to the connecting rod, and the receiving component forms a receiving groove with a through hole at the bottom. The rotor is spherical and rotatably mounted in the receiving groove. The first driving foot is used to drive the rotor to rotate. This invention effectively amplifies the displacement output of the vibrating body and significantly improves the moving speed and load capacity of the piezoelectric actuator, and can realize multi-degree-of-freedom motion. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a three-dimensional structural schematic diagram of the piezoelectric actuator according to an embodiment of the present invention; Figure 2 This is a three-dimensional structural schematic diagram of the piezoelectric actuator from another perspective of an embodiment of the present invention; Figure 3 This is a three-dimensional structural schematic diagram of the piezoelectric actuator from another perspective of an embodiment of the present invention; Figure 4 This is a three-dimensional structural diagram of the connection component of the piezoelectric actuator according to an embodiment of the present invention; Figure 5 This is a partial three-dimensional structural diagram of the connection component of the piezoelectric actuator according to an embodiment of the present invention; Figure 6 for Figure 5 A magnified structural diagram at point A; Figure 7 This is a three-dimensional structural schematic diagram of the ball bearing of the piezoelectric actuator according to an embodiment of the present invention; Figure 8 This is a three-dimensional structural schematic diagram of the stator and piezoelectric ceramic component of the piezoelectric actuator according to an embodiment of the present invention; Figure 9 This is a three-dimensional structural schematic diagram of the stator and piezoelectric ceramic component of the piezoelectric actuator according to an embodiment of the present invention; Figure 10 This is an exploded structural diagram of the stator and piezoelectric ceramic component of the piezoelectric actuator according to an embodiment of the present invention; Figure 11This is a schematic diagram of the tensile vibration mode of the piezoelectric actuator during linear motion according to an embodiment of the present invention; Figure 12 This is a schematic diagram of the bending vibration mode of the piezoelectric actuator during rotational motion according to an embodiment of the present invention.

[0019] Explanation of icon numbers: 100. Piezoelectric actuator; 1. Rotor; 2. Stator; 21. Vibrating body; 211. Rectangular component; 212. First hollow frame; 213. Second hollow frame; 22. First drive foot; 23. Second drive foot; 24. Connecting rod; 241. Connecting end; 3. Piezoelectric ceramic component; 31. Piezoelectric ceramic sheet; 4. Connecting component; 41. Base plate; 42. Side plate; 421. Slot; 43. Limiting rod; 5. Receiving component; 51. Hemispherical shell; 511. Inner wall surface; 52. Through hole; 53. Mounting groove; 531. Step; 6. Ball bearing; 61. Body; 62. Abutment plate; 63. Rolling ball.

[0020] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] 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 the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0024] Piezoelectric actuators are a type of special driving element that converts electrical energy into mechanical energy based on the inverse piezoelectric effect, and completes the power output through friction. Compared with traditional electromagnetic motors, piezoelectric actuators have significant advantages such as compact structure, rapid response, self-locking upon power failure, and no electromagnetic interference. They show broad application prospects in fields with stringent requirements for precision and integration, such as optical focusing, micro-robotics, aerospace, and microelectromechanical systems.

[0025] However, current piezoelectric actuators employing stick-slip or inchworm motion mechanisms are limited by the inherent limitations of piezoelectric ceramic materials, such as small vibration displacement and limited mechanical output capabilities. Their thrust and power densities are generally low, making it difficult to meet practical engineering requirements for movement speed and load-bearing capacity. Meanwhile, traditional piezoelectric actuators with simple geometric configurations, such as rectangular or cylindrical shapes, typically only achieve single-degree-of-freedom motion output through a combination of two vibration modes, failing to meet the flexibility and controllability requirements of complex motion scenarios. Achieving multi-degree-of-freedom motion often requires the simultaneous excitation of multiple vibration modes at the same frequency, which significantly increases the design complexity of the actuator's structural dimensions.

[0026] The applicant discovered through research that if a driving foot is simultaneously installed on the vibrating body and cooperates with a rotatable spherical rotor, so that the driving foot directly drives the rotor to rotate, and the vibration displacement is transmitted and amplified through the rolling contact between the rotor and the robot's contact surface, and the switching between linear and rotational motion is achieved by using the frequency division excitation of tensile vibration and orthogonal bending vibration, then the above-mentioned speed and load bottlenecks can be effectively overcome, and the multi-degree-of-freedom motion capability of the actuator can be significantly improved.

[0027] Based on this, this application proposes a piezoelectric actuator with a stator-rotor composite structure.

[0028] Please see Figures 1 to 3This invention proposes a piezoelectric actuator 100, including a stator 2, a connecting assembly, and a rotor 1. The stator 2 includes a vibrating body 21 and a first driving foot 22 and a second driving foot 23 respectively disposed on the vibrating body 21. A piezoelectric ceramic component 3 is disposed on the outer periphery of the vibrating body 21, and the vibrating body 21 is also provided with a connecting rod 24. The connecting assembly includes a connecting member 4 and a receiving member 5 connected to each other. The connecting member 4 is connected to the connecting rod 24, and the receiving member 5 forms a receiving groove. A through hole 52 is provided at the bottom of the receiving groove. The rotor 1 is spherical in shape and is rotatably mounted in the receiving groove. The first driving foot 22 is used to drive the rotor 1 to rotate.

[0029] Specifically, the piezoelectric actuator 100 can be used in a robot as a power component to drive the robot's overall movement. The vibrating body 21 is the core vibrating component of the piezoelectric actuator 100, which generates high-frequency mechanical vibration through the inverse piezoelectric effect of the piezoelectric ceramic component 3. The first driving foot 22 and the second driving foot 23 are fixedly disposed at both ends of the vibrating body 21, both of which can be used to contact external components to achieve power transmission. The piezoelectric ceramic component 3 is attached to the outer peripheral surface of the vibrating body 21 to receive the excitation voltage and generate corresponding extension or bending deformation modes, thereby exciting the vibrating body 21 to produce specific modal vibrations. The connecting rod 24 is disposed on the vibrating body 21 to achieve a fixed connection between the stator 2 and the connecting assembly. The connecting member 4, as an intermediate connecting component, is fixedly connected to the connecting rod 24 and the receiving member 5, respectively. The receiving member 5 is a shell structure with an internal receiving groove for accommodating and positioning the rotor 1. The shape of the receiving groove is adapted to the spherical shape of the rotor 1, allowing the rotor 1 to rotate freely within the receiving groove. The through hole 52 at the bottom of the receiving groove provides a channel for the rotor 1 to extend out of the receiving groove, allowing the first drive foot 22 to directly contact the surface of the rotor 1. When an excitation voltage is applied to the piezoelectric ceramic component 3, the vibrator 21 vibrates and drives the first drive foot 22 to perform high-frequency micro-displacement motion. The rotor 1 is positioned in the receiving groove with its bottom extending out of the through hole 52. The first drive foot 22 intermittently contacts and rubs against the surface of the bottom of the rotor 1, thereby driving the rotor 1 to rotate around its own axis within the receiving groove. Of course, in other embodiments, the first drive foot 22 can also be positioned to pass through the through hole 52 and contact the rotor 1. The second drive foot 23 can also contact another rotor 1, or directly contact the ground or the robot's contact surface to achieve the transmission of mechanical motion. By converting the high-frequency vibration of the stator 2 into the rotational motion of the rotor 1, the displacement of the vibrator 21 is amplified, which can also drive the movement of the entire robot. Furthermore, the rotational motion of the rotor 1 reacts to the vibrator 21 through the connecting component and the first drive foot 22 rod, thereby driving the entire piezoelectric actuator 100 to achieve rotational motion (i.e., rotation around its own axis). The rotational speed and direction can be controlled by adjusting the amplitude and phase of the excitation voltage. Simultaneously, the first driving foot 22 and the second driving foot 23 are respectively positioned at both ends of the vibrating body 21, making the power output of the piezoelectric actuator 100 more balanced, which is beneficial to improving the smoothness and controllability of the motion. This embodiment effectively amplifies the displacement output of the vibrating body 21 and significantly improves the moving speed and load capacity of the piezoelectric actuator 100, and can achieve multi-degree-of-freedom motion.

[0030] Please see Figure 3 and Figure 4In some embodiments, the housing 5 is a hemispherical shell 51, the bottom of the hemispherical shell 51 is provided with a through hole 52, the rotor 1 is provided to extend out of the opening at the top of the hemispherical shell 51, the inner wall surface 511 of the hemispherical shell 51 extends outward to form a mounting groove 53, a ball bearing 6 is provided in the mounting groove 53, and the ball bearing 6 abuts against the rotor 1.

[0031] Specifically, the hemispherical shell 51 is a shell component with a hemispherical internal cavity. A through hole 52 is opened at its bottom for the rotor 1 to contact the first drive foot 22, and a circular opening is formed at its top. The rotor 1 is entirely housed within the internal cavity of the hemispherical shell 51, with the upper portion of the rotor 1 extending partially from the circular opening at the top to contact the external support surface and achieve rolling drive. The inner wall surface 511 of the hemispherical shell 51 is recessed outward to form a mounting groove 53, which is used to accommodate and position the ball bearing 6. The ball bearing 6 is disposed within the mounting groove 53, with its inner ring or rolling element abutting against the outer surface of the rotor 1. Through the rolling contact between the ball bearing 6 and the rotor 1, the frictional resistance experienced by the rotor 1 during rotation is significantly reduced. Simultaneously, the ball bearing 6 also provides radial and axial positioning for the rotor 1, preventing it from shifting or moving during high-speed rotation. The hemispherical shell 51 is designed so that most of the spherical surface of the rotor 1 is enclosed in the shell, which not only ensures the stable positioning of the rotor 1, but also allows the rotor 1 to be partially exposed to the outside to achieve rolling contact with the robot's support surface or the ground. The overall structure is compact and highly reliable.

[0032] Please see Figures 4 to 7 In some embodiments, the groove of the mounting groove 53 is provided with a step 531. The ball bearing 6 includes a body 61, an abutment plate 62 disposed on the body 61, and a ball 63. The body 61 is disposed in the mounting groove 53. The abutment plate 62 abuts against the step 531. The ball 63 is partially protruding from the abutment plate 62 and is rotatably mounted on the abutment plate 62. The ball 63 abuts against the rotor 1.

[0033] Specifically, the groove opening of the mounting groove 53 tapers inward to form a step 531 structure, which is used to limit the axial position of the ball bearing 6. The body 61 of the ball bearing 6 is embedded inside the mounting groove 53, specifically near the bottom of the mounting groove 53. In fact, the mounting groove 53 includes a first sub-hole and a second sub-hole that are interconnected. The step 531 is disposed between the first sub-hole and the second sub-hole. The first sub-hole is disposed near the receiving groove of the hemispherical shell 51, and the second sub-hole is disposed near the bottom of the groove. The first sub-hole and the second sub-hole are concentrically arranged, and the diameter of the first sub-hole is larger than the diameter of the second sub-hole. One side of the abutment plate 62 is disposed facing the receiving groove, and the opposite side is disposed facing the bottom of the mounting groove 53 and abuts against the step 531, thereby preventing the ball bearing 6 from falling into the mounting groove 53 axially. The ball 63 is rotatably mounted on the abutment plate 62, and a portion of the ball 63 protrudes from the surface of the abutment plate 62, directly forming rolling contact with the outer surface of the rotor 1. When rotor 1 rotates, the balls 63 roll on the surface of rotor 1, converting sliding friction into rolling friction, which significantly reduces frictional loss between rotor 1 and the bearing. Simultaneously, the fit between the abutment plate 62 and the step 531 ensures the axial positioning accuracy of the ball bearing 6 within the mounting groove 53, allowing the balls 63 to maintain stable contact with the predetermined area of ​​rotor 1, thus ensuring the smoothness and reliability of rotor 1's rotation. Furthermore, the balls 63 also provide positioning and limiting for rotor 1, reducing the risk of rotor 1 falling off or shifting.

[0034] Please see Figure 4 In some embodiments, a gap is provided between the abutment plate 62 and the inner wall surface 511 of the hemispherical shell 51, and the ball bearing 6 also includes an elastic element, the two ends of which are connected to the body 61 and the ball 63 respectively.

[0035] Specifically, a predetermined gap is maintained between the abutment plate 62 and the inner wall surface 511 of the hemispherical shell 51, providing radial floating space for the rolling ball 63. An elastic element is positioned between the body 61 and the rolling ball 63, with one end fixedly connected to the body 61 and the other end connected to the support structure of the rolling ball 63. Under the restoring force of the elastic element, the rolling ball 63 is always pressed against the surface of the rotor 1. Even if the rotor 1 experiences slight radial runout or installation errors during rotation, the elastic element can adaptively adjust the radial position of the rolling ball 63 through its own expansion and contraction deformation, ensuring that the rolling ball 63 always maintains close contact with the rotor 1. The elastic element can be a spring or elastic silicone. This floating support structure effectively compensates for machining and assembly errors of the components, improves the adaptability of the ball bearing 6 to the motion tolerance of the rotor 1, and further enhances the smoothness of the rotor 1's rotation and the efficiency of driving force transmission. Furthermore, when the elastic element is compressed, the restoring force of the elastic element can be used to make the ball 63 and the rotor 1 have a certain contact pressure. Multiple balls 63 press against the rotor 1 from multiple directions, reducing the risk of the rotor 1 falling off or shifting.

[0036] Please see Figures 4 to 6 In some embodiments, there are multiple mounting slots 53, which are distributed circumferentially on the hemispherical shell 51, and a ball bearing 6 is correspondingly provided in each mounting slot 53.

[0037] Specifically, multiple mounting slots 53 are evenly arranged circumferentially along the inner wall surface 511 of the hemispherical shell 51, with equal included angles between adjacent mounting slots 53. Each mounting slot 53 is equipped with an independent ball bearing 6, and multiple ball bearings 6 simultaneously abut against the surface of the rotor 1 from different positions. Through the synergistic action of multiple ball bearings 6, the rotor 1 obtains multi-directional support and positioning within the receiving slot, significantly improving the stability of its rotation axis. At the same time, multiple ball bearings 6 share the radial and axial loads generated during the rotation of the rotor 1, avoiding premature wear or failure of a single bearing due to excessive force, effectively extending the service life of the drive, and improving the rotational accuracy and power output capability of the rotor 1 under high load conditions. In conjunction with the previous embodiment, when the elastic element is compressed, the restoring force of the elastic element can also be used to create a certain contact pressure between the rolling balls 63 and the rotor 1. In this way, multiple rolling balls 63 press against the rotor 1 from multiple directions, reducing the risk of the rotor 1 falling off or shifting.

[0038] Please see Figures 8 to 10In some embodiments, the vibrator 21 includes a rectangular component 211 and a first hollow frame 212 and a second hollow frame 213 disposed at both ends of the rectangular component 211 along a first direction. The first hollow frame 212 is provided with a first driving foot 22, and the second hollow frame 213 is provided with a second driving foot 23. The piezoelectric ceramic component 3 includes four piezoelectric ceramic sheets 31, which are arranged in a hollow square frame shape. The four piezoelectric ceramic sheets 31 are attached to the four sides of the rectangular component 211 in a one-to-one correspondence. The connecting rod 24 is disposed on the rectangular component 211.

[0039] Specifically, the length direction can be the direction of the centerline of the rectangular component 211, that is, the length direction of the rectangular component 211. The rectangular component 211 is a long strip-shaped base with a rectangular cross-section. A first hollow frame 212 and a second hollow frame 213 are integrally connected to both ends along its length direction, i.e., the first direction. Both the first hollow frame 212 and the second hollow frame 213 are hollow frame structures. This structure effectively reduces mass while ensuring the overall stiffness of the vibrating body 21, which is beneficial for improving the resonance amplitude and vibration response speed. The rectangular component 211 can be set as a solid structure or a hollow structure. The first driving foot 22 is fixedly set on the first hollow frame 212, and the second driving foot 23 is fixed on the second hollow frame 213, both located at the two ends of the vibrating body 21. The piezoelectric ceramic component 3 consists of four independent piezoelectric ceramic sheets 31. The four piezoelectric ceramic sheets 31 are respectively attached to the upper, lower, left, and right sides of the rectangular component 211, forming a hollow square frame structure that encloses the middle section of the rectangular component 211. Each piezoelectric ceramic sheet 31 is polarized along its thickness direction. By applying voltage combinations with different phases and directions to the piezoelectric ceramic sheets 31 at different locations, various vibration modes such as tensile vibration, horizontal bending vibration, and vertical bending vibration can be excited on the vibrator 21. The connecting rod 24 is fixedly installed in the middle of the rectangular piece 211 to fix the stator 2 to the connecting assembly, thus preventing the connecting structure from interfering with the vibration transmission of the driving feet at both ends of the vibrator 21.

[0040] When an excitation voltage of the same amplitude and phase is applied to all piezoelectric ceramic plates 31, tensile vibration is excited on the stator 2. This tensile vibration causes the first drive foot 22 and the second drive foot 23 to vibrate along the length of the stator 2, thus exciting the piezoelectric actuator 100 to move linearly. When an excitation voltage of the same amplitude but opposite phase is applied to the piezoelectric ceramic plates 31 on the left and right sides of the stator 2, horizontal bending vibration is excited on the stator 2, causing the first drive foot 22 and the second drive foot 23 to vibrate left and right. When an excitation voltage of the same amplitude but opposite phase is applied to the piezoelectric ceramic plates 31 on the upper and lower sides of the stator 2, vertical bending vibration is excited on the stator 2, causing the first drive foot 22 and the second drive foot 23 to vibrate up and down. The excitation voltages for horizontal bending vibration and vertical bending vibration differ by 90°, thus exciting the actuator to rotate. The actuator's moving speed can be adjusted by adjusting the amplitude of the excitation voltage. Thus, by applying voltages of different amplitudes or phases to the piezoelectric ceramic sheet 31, multiple motion modes can be excited. By adopting a driving principle that combines single-mode and dual-mode, linear motion is achieved through the stretching mode, and rotational motion is achieved through the orthogonal bending mode, thus realizing multi-degree-of-freedom driving. Figure 11 This is a schematic diagram of the tensile vibration modes during linear motion. Figure 11 In the middle, the left image shows stator 2 in a shortened state. Figure 11 The middle image shows stator 2 in a normal state. Figure 11 In the middle, the right figure shows the stator 2 in an elongated state. Figure 12 This is a schematic diagram of the bending vibration modes during rotational motion. Figure 12 The left figure shows the horizontal bending vibration mode of stator 2 during rotational motion. Figure 12 The right figure shows the vertical bending vibration mode of stator 2 during rotational motion. The first three modes combine to form the tensile mode, and the latter two modes combine to form the orthogonal bending mode. When the system operates at the corresponding resonant frequency, the piezoelectric ceramic sheet 31 at the corresponding position excites the linear and rotational motion of the actuator.

[0041] In the above embodiments, the first driving foot 22 on the vibrator 21 cooperates with the spherical rotor 1 and drives it to rotate. The rotating sphere further drives the robot to move. This application improves the moving speed by adding a rotor 1 structure to transmit and amplify the vibration displacement of the vibrator 21. In addition, under the action of the stretching mode, the second driving foot 23 completes the stepping action to lift off the ground, and the first driving foot 22 can push the rotor 1 to roll forward, enabling the robot to move forward. The bending composite mode generates an elliptical motion trajectory, thereby driving the robot to complete the rotation. Multi-degree-of-freedom motion can be achieved by frequency division excitation of single vibration mode and dual vibration mode.

[0042] Please see Figures 8 to 10In some embodiments, there are two piezoelectric ceramic elements 3, which are spaced apart on the rectangular element 211, and the connecting rod 24 is disposed between the two piezoelectric ceramic elements 3.

[0043] Specifically, two sets of piezoelectric ceramic elements 3 are provided on the rectangular component 211. Each set of piezoelectric ceramic elements 3 consists of four piezoelectric ceramic sheets 31 attached to the four sides of the rectangular component 211. The two sets of piezoelectric ceramic elements 3 are arranged at intervals along the length of the rectangular component 211, forming a blank area between them. The connecting rod 24 is fixedly positioned in this blank area. This arrangement places the connecting rod 24 in the middle of the two sets of piezoelectric ceramic elements 3. When the piezoelectric ceramic elements 3 excite the vibrator 21 to vibrate, the middle area on the vibrator 21 between the two sets of piezoelectric ceramic elements 3 is approximately the node position of the vibration, and the vibration displacement amplitude in this area is the smallest. Placing the connecting rod 24 at the node position with the smallest vibration amplitude can minimize the transmission of stator 2 vibration to the connecting assembly and housing 5, avoid the dissipation of vibration energy through the connecting structure, and thus ensure that the vibration energy of the drive foot is concentrated for driving the rotor 1 to rotate, effectively improving the energy conversion efficiency and the overall performance of the drive.

[0044] Please see Figure 3 , Figure 5 and Figure 8 In some embodiments, the connecting rod 24 extends through the rectangular member 211 along the second direction and has two connecting ends 241. The connecting member 4 includes a base plate 41 and two side plates 42 respectively disposed on opposite sides of the base plate 41. The base plate 41 is connected to the receiving member 5. The two side plates 42 are disposed on opposite sides of the rectangular member 211 along the second direction, and the two side plates 42 are connected to the two connecting ends 241 one-to-one. The first direction is perpendicular to the second direction.

[0045] Specifically, the second direction is perpendicular to the first direction, i.e., the second direction is the width direction of the rectangular member 211. The connecting rod 24 is disposed along the second direction through the rectangular member 211, with its two ends extending from the left and right sides of the rectangular member 211 respectively, forming two connecting ends 241. The connecting member 4 adopts a U-shaped structure, including a base plate 41 and two side plates 42, which are fixedly connected to the opposite two edges of the base plate 41. The base plate 41 is fixedly connected to the outer wall of the receiving member 5, and the two side plates 42 are located on the left and right sides of the rectangular member 211 along the width direction, with each side plate 42 corresponding to a connecting end 241. For example, a slot 421 can be provided on the side plate 42, and the connecting section can be movably connected in the slot 421 through the slot opening. By simultaneously connecting the two side plates 42 to the two connecting ends 241, a double-point fixed connection structure is formed between the connecting member 4 and the stator 2, which has high connection strength and balanced force, and can effectively suppress the resonance or loosening of the connecting member 4 when the stator 2 vibrates. Meanwhile, the connection between the substrate 41 and the housing 5 makes the entire connection assembly integrate the stator 2 and the housing 5 into a whole, with a compact structure and easy assembly.

[0046] Please see Figure 3 and Figure 4 In some embodiments, the connector 4 further includes a limiting rod 43, which is disposed at the end of the side plate 42 away from the substrate 41. The limiting rod 43 connects the two side plates 42, and the limiting rod 43 and the substrate 41 are respectively disposed on both sides of the rectangular member 211. The limiting rod 43 connecting the two side plates 42 can play a reinforcing role, and the limiting rod 43 is disposed on the side of the rectangular member 211 away from the substrate 41, which can play a limiting role and prevent the side plate 42 from falling off the rectangular member 211.

[0047] Please see Figure 8 and Figure 9 In some embodiments, there are two first drive feet 22. Alternatively, the position where the first drive foot 22 abuts against the rotor 1 is rounded. Alternatively, there are two second drive feet 23. Alternatively, the end of the second drive foot 23 away from the vibrator 21 is rounded.

[0048] Specifically, the first drive foot 22 includes two independent foot structures. The two first drive feet 22 are arranged side by side on the first hollow frame 212, and both pass through the through hole 52 to contact the surface of the rotor 1. The two first drive feet 22 drive the rotor 1 to rotate simultaneously, increasing the transmission area of ​​the driving torque and the number of friction contact points, thereby improving driving efficiency and output torque. The end of the first drive foot 22 that abuts against the rotor 1 is machined into an arc-shaped round head structure. The round head structure can increase the contact adaptability with the surface of the rotor 1. Even if there is a certain eccentricity or angular deviation in the installation of the rotor 1, the round head structure can still form a stable contact with the surface of the rotor 1, avoiding stress concentration and surface scratches that may be caused by sharp corner contact. Similarly, there are also two second drive feet 23. The two second drive feet 23 are arranged side by side on the second hollow frame 213, and are used to contact the external support surface on the other side to realize auxiliary support and motion guidance of the actuator. The end of the second drive foot 23 away from the vibrator 21 is also set as a round head structure. The round head structure can reduce the contact area between the second drive foot 23 and the ground, thereby reducing frictional resistance and improving the flexibility and response speed of the actuator when switching between linear motion and rotational motion.

[0049] In some embodiments, the piezoelectric actuator 100 of this application can also adopt the following alternative: changing the size and shape of the main body of the vibrating body 21, for example, replacing the rectangular part 211 with a cylindrical part or other long strip-shaped component with a polygonal cross-section, while still being able to excite tensile vibration and orthogonal bending vibration by reasonably arranging the contact positions of the piezoelectric ceramic plates 31. The number of piezoelectric ceramic groups can also be increased or decreased according to the actual driving force and speed requirements, for example, changing four piezoelectric ceramic plates 31 in each group to two or six pieces, while still being able to achieve the same vibration mode excitation function by applying voltage combinations with different phases and directions to the piezoelectric ceramic plates 31 at different positions. In addition, the material of the rotor 1 is not limited to stainless steel, and ceramic balls, bearing steel balls, or other spherical components with high hardness and high wear resistance can also be selected.

[0050] According to some embodiments of this application, this application also provides a robot, which includes a housing and a piezoelectric actuator 100 as described above disposed within the housing. The piezoelectric actuator 100 is fixedly installed inside the robot's housing, with its rotor 1 extending from the bottom of the housing to contact an external support surface. The robot housing also integrates a drive circuit and a wireless communication module. The drive circuit provides an excitation voltage signal of specific frequency, amplitude, and phase to the piezoelectric ceramic element 3 of the piezoelectric actuator 100, and the wireless communication module receives external control commands. After the robot is powered on, it receives control signals through the wireless communication module, then determines the type of the control signal and outputs a corresponding control signal to the drive circuit. The drive circuit applies voltage combinations of different phases and directions to the tensile piezoelectric ceramic sheet 31 and two sets of torsional piezoelectric ceramic sheets 31 according to the control signals, causing the piezoelectric actuator 100 to generate torsional and tensile vibrations of different orders, driving the robot to achieve various motion modes such as linear motion, rotational motion, or rotation around a center. Since the robot incorporates all the technical solutions of any embodiment of the piezoelectric actuator 100 described above, it possesses at least all the beneficial effects brought about by all the above technical solutions, which will not be elaborated upon here.

[0051] The above are merely exemplary embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A piezoelectric actuator, characterized in that, include: The stator includes a vibrating body and a first driving foot and a second driving foot respectively disposed on the vibrating body. A piezoelectric ceramic component is disposed on the outer periphery of the vibrating body, and the vibrating body is also provided with a connecting rod. A connecting assembly, comprising a connector and a receiving member connected to each other, the connector being connected to the connecting rod, the receiving member forming a receiving groove, and a through hole being provided at the bottom of the receiving groove; The rotor is spherical in shape and is rotatably mounted in the receiving groove. The first driving foot is used to drive the rotor to rotate.

2. The piezoelectric actuator according to claim 1, characterized in that, The receiving component is a hemispherical shell, the bottom of which is provided with the through hole, the rotor portion extends out of the opening at the top of the hemispherical shell, and the inner wall portion of the hemispherical shell extends outward to form a mounting groove, in which a ball bearing is provided, and the ball bearing abuts against the rotor.

3. The piezoelectric actuator according to claim 2, characterized in that, The mounting groove has a step at its opening. The ball bearing includes a body, an abutment plate disposed on the body, and a ball bearing. The body is disposed in the mounting groove. The abutment plate abuts against the step. The ball bearing protrudes from the abutment plate and is rotatably mounted on the abutment plate. The ball bearing is rotatably connected to the rotor.

4. The piezoelectric actuator according to claim 3, characterized in that, A gap is formed between the abutment plate and the inner wall surface of the hemispherical shell, and the ball bearing further includes an elastic element, the two ends of which are respectively connected to the body and the rolling ball.

5. The piezoelectric actuator according to claim 2, characterized in that, The number of mounting slots is multiple, and the multiple mounting slots are distributed circumferentially on the hemispherical shell. A ball bearing is correspondingly provided in each mounting slot.

6. The piezoelectric actuator according to any one of claims 1 to 5, characterized in that, The vibrating body includes a rectangular component and a first hollow frame and a second hollow frame disposed at both ends of the rectangular component along a first direction. The first hollow frame is provided with the first driving foot, and the second hollow frame is provided with the second driving foot. The piezoelectric ceramic component includes four piezoelectric ceramic sheets, which are arranged to form a hollow square frame. The four piezoelectric ceramic sheets are attached to the four sides of the rectangular component one by one. The connecting rod is disposed on the rectangular component.

7. The piezoelectric actuator according to claim 6, characterized in that, The number of piezoelectric ceramic components is two, and the two piezoelectric ceramic components are spaced apart on the rectangular component, with the connecting rod disposed between the two piezoelectric ceramic components.

8. The piezoelectric actuator according to claim 7, characterized in that, The connecting rod extends through the rectangular member along the second direction to form two connecting ends. The connecting member includes a base plate and two side plates respectively disposed on opposite sides of the base plate. The base plate is connected to the receiving member. The two side plates are disposed on opposite sides of the rectangular member along the second direction. The two side plates are connected to the two connecting ends one by one. The first direction is perpendicular to the second direction.

9. The piezoelectric actuator according to any one of claims 1 to 5, characterized in that, The number of the first driving feet is two; And / or, the position where the first driving foot abuts against the rotor is set to a rounded head; And / or, the number of the second driving feet is two; And / or, the end of the second driving foot away from the vibrator is configured as a round head.

10. A robot, characterized in that, The robot includes a housing and a piezoelectric actuator as described in any one of claims 1 to 9 disposed within the housing.

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