Six-degree-of-freedom platform for active vibration isolation

Abstract

The invention discloses a six-degree-of-freedom platform for active vibration isolation. The six-degree-of-freedom platform comprises a vibration isolation platform, a piezoelectric actuation module, a shell, a base, a sensing module and a control module, the piezoelectric actuation module comprises twelve piezoelectric actuators; the piezoelectric actuator structure comprises a beam body, a connecting column, a pre-tightening bolt and six piezoelectric ceramic pieces; the sensing module comprises four acceleration sensors. The six-degree-of-freedom vibration of the vibration isolation platform can be accurately controlled through the twelve piezoelectric actuators, the control system is high in stability and simple in structure, the vibration isolation performance and precision of equipment can be effectively improved, installation and maintenance are easy, and wide application prospects are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of vibration isolation, and in particular to a six-degree-of-freedom platform for active vibration isolation. Background Art

[0002] In many fields such as precision instruments and equipment, scientific experiments, and industrial production, vibration can have a serious impact on the performance and accuracy of equipment. Traditional vibration isolation technology can usually only isolate vibrations in a single degree of freedom, which is difficult to meet the needs of modern technology for multi-degree-of-freedom vibration isolation. With the continuous advancement of science and technology, the requirements for the vibration isolation performance, accuracy, and stability of the vibration isolation platform are getting higher and higher. Therefore, the development of an efficient multi-degree-of-freedom vibration isolation platform has important practical significance.

[0003] Piezoelectric vibration control technology provides a new way to realize efficient multi-degree-of-freedom vibration isolation platforms. Piezoelectric materials have the advantages of fast response speed, high control accuracy, and high energy conversion efficiency. By reasonably arranging piezoelectric elements in the vibration isolation platform, it is possible to accurately control vibrations in multiple degrees of freedom. When external vibrations are transmitted to the vibration isolation platform, the piezoelectric element can quickly sense the vibration signal and generate a reverse force by applying the corresponding voltage, thereby offsetting the vibration energy and reducing the vibration amplitude of the platform. Compared with traditional vibration isolation technology, the multi-degree-of-freedom vibration isolation platform based on piezoelectric vibration control has the following significant advantages. First, it can simultaneously isolate vibrations in multiple degrees of freedom, effectively improving the vibration isolation effect and meeting the needs of precision instruments and scientific experiments for high-precision vibration isolation. Secondly, the rapid response characteristics of piezoelectric elements enable the vibration isolation platform to adapt to different vibration environments in real time, ensuring the stability and reliability of the equipment. Furthermore, through the feedforward control algorithm, the piezoelectric element can be accurately controlled to achieve targeted suppression of vibrations of different frequencies and amplitudes, further improving the vibration isolation performance.

[0004] In the field of precision instrument manufacturing, equipment such as photolithography machines and electron microscopes are extremely sensitive to vibration. The multi-degree-of-freedom vibration isolation platform using piezoelectric vibration control can provide a stable working environment for these devices, ensuring that their high-precision performance can be fully utilized. In scientific experiments, many experiments need to be carried out in an extremely low-vibration environment. The piezoelectric vibration isolation platform can effectively isolate external interference and ensure the accuracy and reliability of the experimental results. In industrial production, some high-precision processing equipment also requires good vibration isolation performance to improve product quality and production efficiency. The multi-degree-of-freedom vibration isolation platform controlled by piezoelectric vibration provides an ideal solution for these application scenarios. In short, the application of piezoelectric vibration control technology in the multi-degree-of-freedom vibration isolation platform has brought new opportunities for equipment performance improvement and precision assurance in many fields, and has broad development prospects and important practical significance. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a six-degree-of-freedom platform for active vibration isolation, which can effectively isolate vibrations from six degrees of freedom and improve the performance and accuracy of the equipment.

[0006] A six-degree-of-freedom platform for active vibration isolation, comprising a vibration isolation platform, a piezoelectric actuation module, a housing, a base, a sensing module and a control module; The base is a square plate used for fixing to the outside world; The shell is a hollow regular quadrangular prism with openings at both ends, the lower end of the shell is coaxially fixedly connected to the base, and the four side surfaces of the shell and the four sides of the base are parallel and correspond to each other; The piezoelectric actuation module comprises first to twelfth piezoelectric actuators; The first to twelfth piezoelectric actuators have the same structure, and all include a beam body, a connecting column, a pre-tightening bolt, and first to sixth piezoelectric ceramic sheets; The beam body is a cylinder; The side wall of the connecting column is provided with an external thread, and the outer diameter of the thread is smaller than the diameter of the cross section of the beam body; A pre-tightening threaded blind hole matching the pre-tightening bolt is provided at the center of one end of the beam body, and the other end is coaxially fixedly connected to one end of the connecting column; The first to sixth piezoelectric ceramic sheets have the same structure and the same cross-sectional shape as the beam body, and are all provided with through holes in the center for the pre-tightening bolts to pass through; the first to sixth piezoelectric ceramic sheets are stacked in sequence, and are all polarized along the thickness direction, and the polarization directions of adjacent piezoelectric ceramic sheets are opposite; The vibration isolation platform is in the shape of a cube, comprising an upper end surface, a lower end surface, and first to fourth side walls connected in sequence end to end; The first side wall of the vibration isolation platform is respectively provided with a first and a second threaded blind hole for matching with the connecting posts of the first and the second piezoelectric actuators, the second side wall is respectively provided with a third and a fourth threaded blind hole for matching with the connecting posts of the third and the fourth piezoelectric actuators, the third side wall is respectively provided with a fifth and a sixth threaded blind hole for matching with the connecting posts of the fifth and the sixth piezoelectric actuators, and the fourth side wall is respectively provided with a seventh and an eighth threaded blind hole for matching with the connecting posts of the seventh and the eighth piezoelectric actuators; the first and the sixth threaded blind holes are coaxial and located on a straight line L1; the second and the fifth threaded blind holes are coaxial and located on a straight line L2; the third and the eighth threaded blind holes are coaxial and located on a straight line L3; the fourth and the seventh threaded blind holes are coaxial and located on a straight line L4; the straight lines L1, L2, L3, and L4 are coplanar and mutually perpendicular in sequence, forming a square D with its center located on the axis of the upper end face of the vibration isolation platform; The lower end surface of the vibration isolation platform is provided with ninth to twelfth threaded blind holes respectively matched with the connecting columns of the ninth to twelfth piezoelectric actuators, and the axes of the ninth to twelfth threaded blind holes correspond to each other and pass through the four vertices of the square D. The upper end surface of the vibration isolation platform is evenly provided with a number of fixed threaded blind holes for fixing to the outside world; The vibration isolation platform is arranged in the shell, the lower end surface of which is parallel to the base, and the first to fourth side walls are parallel to the four side walls of the shell respectively in one-to-one correspondence; The four side walls of the housing are provided with first to eighth mounting through holes which are coaxially corresponding to the first to eighth threaded blind holes, and the base is provided with ninth to twelfth mounting through holes which are coaxially corresponding to the ninth to twelfth threaded blind holes; The first to twelfth piezoelectric actuators are arranged one by one between the first to twelfth threaded blind holes and the first to twelfth mounting through holes, and their pre-tightening bolts are sequentially passed through the corresponding mounting through holes and the first to sixth piezoelectric ceramic sheets and then threadedly connected with the pre-tightening threaded blind holes on the beam body to tighten the first to sixth piezoelectric ceramic sheets; their connecting columns are threadedly connected with their corresponding threaded blind holes, so that one end of the beam body away from the first piezoelectric ceramic sheet abuts against the vibration isolation platform; The sensing module includes first to fourth acceleration sensors, wherein the first and second acceleration sensors are both arranged on the outer wall of the shell, the first acceleration sensor is located at the midpoint between the pre-tightening bolts of the first and second piezoelectric actuators, and the second acceleration sensor is located at the midpoint between the pre-tightening bolts of the seventh and eighth piezoelectric actuators; the third acceleration sensor is arranged on the upper end surface of the base outside the first acceleration sensor, and is located on the symmetric plane between the pre-tightening bolts of the first and second piezoelectric actuators; the fourth acceleration sensor is arranged on the upper end surface of the base outside the second acceleration sensor, and is located on the symmetric plane between the pre-tightening bolts of the seventh and eighth piezoelectric actuators; The control module is electrically connected to the first to twelfth piezoelectric actuators and the first to fourth acceleration sensors respectively, and is used to control the first to twelfth piezoelectric actuators to work according to the sensing data of the first to fourth acceleration sensors to offset the vibration received by the vibration isolation platform.

[0007] As a further optimization solution of the six-degree-of-freedom platform for active vibration isolation of the present invention, the beam body is provided with an annular groove whose width gradually narrows from the outside to the inside, so that a flexible hinge is formed on the beam body to amplify the amplitude.

[0008] The working principle of the present invention is as follows: the center of the vibration isolation platform is taken as the origin, the direction parallel to the axis of the first piezoelectric actuating unit is taken as the x direction, the direction parallel to the axis of the third piezoelectric actuating unit is taken as the y direction, and the axis of the base is taken as the z direction; when working, the control module receives the sensing data of the first to fourth acceleration sensors, and respectively calculates the vibration changes in the six degrees of freedom of the x direction, the y direction, the z direction, around the x direction, around the y direction, and around the z direction; when the vibration displacement in the x direction occurs, the control module controls the first, second, fifth, and sixth piezoelectric actuators to work and offset; when the vibration displacement in the y direction occurs, the control module controls the third, fourth, seventh, and eighth piezoelectric actuators to work and offset; when the displacement in the z direction occurs, the control module controls the ninth to twelfth piezoelectric actuators to work and offset; when the twisting around the x direction or around the y direction occurs, the control module controls the ninth to twelfth piezoelectric actuators to work and offset; when the twisting around the z direction occurs, the control module controls the first to eighth piezoelectric actuators to work and offset.

[0009] The present invention has the following advantages: 1. It can effectively isolate vibrations from six degrees of freedom and improve the vibration isolation performance and accuracy of the equipment; 2. Piezoelectric actuators have fast response speed, high control accuracy, and high energy conversion efficiency, and can achieve precise control of vibration; 3. The control module can monitor and control the vibration state of the platform body in real time according to the feedforward control principle to ensure the stability and reliability of the vibration isolation effect; 4. The structure of the platform body and the piezoelectric actuator is simple, easy to install and maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic structural diagram of the first piezoelectric actuator in the present invention.

[0011] In the figure, 1-vibration isolation platform, 2-shell, 3-base, 4-first piezoelectric actuator, 5-second piezoelectric actuator, 6-fourth piezoelectric actuator, 7-first acceleration sensor, 8-second acceleration sensor, 9-third acceleration sensor, 10-fourth acceleration sensor, 11-pre-tightening bolt of the first piezoelectric actuator, 12-beam, 13-connecting column, 14-first piezoelectric ceramic sheet. DETAILED DESCRIPTION

[0012] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0013] The present invention can be implemented in many different forms and should not be considered to be limited to the embodiments described herein. On the contrary, these embodiments are provided to make this disclosure thorough and complete, and will fully express the scope of the present invention to those skilled in the art. In the accompanying drawings, components are enlarged for clarity.

[0014] like Figure 1 As shown, the present invention discloses a six-degree-of-freedom platform for active vibration isolation, comprising a vibration isolation platform, a piezoelectric actuation module, a housing, a base, a sensing module and a control module; The base is a square plate used for fixing to the outside world; The shell is a hollow regular quadrangular prism with openings at both ends, the lower end of the shell is coaxially fixedly connected to the base, and the four side surfaces of the shell and the four sides of the base are parallel and correspond to each other; The piezoelectric actuation module comprises first to twelfth piezoelectric actuators; The first to twelfth piezoelectric actuators have the same structure, and all include a beam body, a connecting column, a pre-tightening bolt, and first to sixth piezoelectric ceramic sheets; The beam body is a cylinder; The side wall of the connecting column is provided with an external thread, and the outer diameter of the thread is smaller than the diameter of the cross section of the beam body; A pre-tightening threaded blind hole matching the pre-tightening bolt is provided at the center of one end of the beam body, and the other end is coaxially fixedly connected to one end of the connecting column; The first to sixth piezoelectric ceramic sheets have the same structure and the same cross-sectional shape as the beam body, and are all provided with through holes in the center for the pre-tightening bolts to pass through; the first to sixth piezoelectric ceramic sheets are stacked in sequence, and are all polarized along the thickness direction, and the polarization directions of adjacent piezoelectric ceramic sheets are opposite; The vibration isolation platform is in the shape of a cube, comprising an upper end surface, a lower end surface, and first to fourth side walls connected in sequence end to end; The first side wall of the vibration isolation platform is respectively provided with a first and a second threaded blind hole for matching with the connecting posts of the first and the second piezoelectric actuators, the second side wall is respectively provided with a third and a fourth threaded blind hole for matching with the connecting posts of the third and the fourth piezoelectric actuators, the third side wall is respectively provided with a fifth and a sixth threaded blind hole for matching with the connecting posts of the fifth and the sixth piezoelectric actuators, and the fourth side wall is respectively provided with a seventh and an eighth threaded blind hole for matching with the connecting posts of the seventh and the eighth piezoelectric actuators; the first and the sixth threaded blind holes are coaxial and located on a straight line L1; the second and the fifth threaded blind holes are coaxial and located on a straight line L2; the third and the eighth threaded blind holes are coaxial and located on a straight line L3; the fourth and the seventh threaded blind holes are coaxial and located on a straight line L4; the straight lines L1, L2, L3, and L4 are coplanar and mutually perpendicular in sequence, forming a square D with its center located on the axis of the upper end face of the vibration isolation platform; The lower end surface of the vibration isolation platform is provided with ninth to twelfth threaded blind holes respectively matched with the connecting columns of the ninth to twelfth piezoelectric actuators, and the axes of the ninth to twelfth threaded blind holes correspond to each other and pass through the four vertices of the square D. The upper end surface of the vibration isolation platform is evenly provided with a number of fixed threaded blind holes for fixing to the outside world; The vibration isolation platform is arranged in the shell, the lower end surface of which is parallel to the base, and the first to fourth side walls are parallel to the four side walls of the shell respectively in one-to-one correspondence; The four side walls of the housing are provided with first to eighth mounting through holes which are coaxially corresponding to the first to eighth threaded blind holes, and the base is provided with ninth to twelfth mounting through holes which are coaxially corresponding to the ninth to twelfth threaded blind holes; The first to twelfth piezoelectric actuators are arranged one by one between the first to twelfth threaded blind holes and the first to twelfth mounting through holes, and their pre-tightening bolts are sequentially passed through the corresponding mounting through holes and the first to sixth piezoelectric ceramic sheets and then threadedly connected with the pre-tightening threaded blind holes on the beam body to tighten the first to sixth piezoelectric ceramic sheets; their connecting columns are threadedly connected with their corresponding threaded blind holes, so that one end of the beam body away from the first piezoelectric ceramic sheet abuts against the vibration isolation platform; The sensing module includes first to fourth acceleration sensors, wherein the first and second acceleration sensors are both arranged on the outer wall of the shell, the first acceleration sensor is located at the midpoint between the pre-tightening bolts of the first and second piezoelectric actuators, and the second acceleration sensor is located at the midpoint between the pre-tightening bolts of the seventh and eighth piezoelectric actuators; the third acceleration sensor is arranged on the upper end surface of the base outside the first acceleration sensor, and is located on the symmetric plane between the pre-tightening bolts of the first and second piezoelectric actuators; the fourth acceleration sensor is arranged on the upper end surface of the base outside the second acceleration sensor, and is located on the symmetric plane between the pre-tightening bolts of the seventh and eighth piezoelectric actuators; The control module is electrically connected to the first to twelfth piezoelectric actuators and the first to fourth acceleration sensors respectively, and is used to control the first to twelfth piezoelectric actuators to work according to the sensing data of the first to fourth acceleration sensors to offset the vibration received by the vibration isolation platform.

[0015] like Figure 2 As shown, the beam body may also be provided with an annular groove whose width gradually narrows from the outside to the inside, so that a flexible hinge is formed on the beam body to amplify the amplitude.

[0016] The working principle of the present invention is as follows: the center of the vibration isolation platform is taken as the origin, the direction parallel to the axis of the first piezoelectric actuating unit is taken as the x direction, the direction parallel to the axis of the third piezoelectric actuating unit is taken as the y direction, and the axis of the base is taken as the z direction; when working, the control module receives the sensing data of the first to fourth acceleration sensors, and respectively calculates the vibration changes in the six degrees of freedom of the x direction, the y direction, the z direction, around the x direction, around the y direction, and around the z direction; when the vibration displacement in the x direction occurs, the control module controls the first, second, fifth, and sixth piezoelectric actuators to work and offset; when the vibration displacement in the y direction occurs, the control module controls the third, fourth, seventh, and eighth piezoelectric actuators to work and offset; when the displacement in the z direction occurs, the control module controls the ninth to twelfth piezoelectric actuators to work and offset; when the twisting around the x direction or around the y direction occurs, the control module controls the ninth to twelfth piezoelectric actuators to work and offset; when the twisting around the z direction occurs, the control module controls the first to eighth piezoelectric actuators to work and offset.

[0017] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A six-degree-of-freedom platform for active vibration isolation, characterized in that: It includes a vibration isolation platform, a piezoelectric actuation module, a housing, a base, a sensing module and a control module; The base is a square plate used for fixing to the outside world; The shell is a hollow regular quadrangular prism with openings at both ends, the lower end of the shell is coaxially fixedly connected to the base, and the four side surfaces of the shell and the four sides of the base are parallel and correspond one to one; The piezoelectric actuation module comprises first to twelfth piezoelectric actuators; The first to twelfth piezoelectric actuators have the same structure, and all include a beam body, a connecting column, a pre-tightening bolt, and first to sixth piezoelectric ceramic sheets; The beam body is a cylinder; The side wall of the connecting column is provided with an external thread, and the outer diameter of the thread is smaller than the diameter of the cross section of the beam body; A pre-tightening threaded blind hole matching the pre-tightening bolt is provided at the center of one end of the beam body, and the other end is coaxially fixedly connected to one end of the connecting column; The first to sixth piezoelectric ceramic sheets have the same structure and the same cross-sectional shape as the beam body, and are all provided with through holes in the center for the pre-tightening bolts to pass through; the first to sixth piezoelectric ceramic sheets are stacked in sequence, and are all polarized along the thickness direction, and the polarization directions of adjacent piezoelectric ceramic sheets are opposite; The vibration isolation platform is in the shape of a cube, comprising an upper end surface, a lower end surface, and first to fourth side walls connected in sequence end to end; The first side wall of the vibration isolation platform is respectively provided with a first and a second threaded blind hole for matching with the connecting posts of the first and the second piezoelectric actuators, the second side wall is respectively provided with a third and a fourth threaded blind hole for matching with the connecting posts of the third and the fourth piezoelectric actuators, the third side wall is respectively provided with a fifth and a sixth threaded blind hole for matching with the connecting posts of the fifth and the sixth piezoelectric actuators, and the fourth side wall is respectively provided with a seventh and an eighth threaded blind hole for matching with the connecting posts of the seventh and the eighth piezoelectric actuators; the first and the sixth threaded blind holes are coaxial and located on a straight line L1; the second and the fifth threaded blind holes are coaxial and located on a straight line L2; the third and the eighth threaded blind holes are coaxial and located on a straight line L3; the fourth and the seventh threaded blind holes are coaxial and located on a straight line L4; the straight lines L1, L2, L3, and L4 are coplanar and mutually perpendicular in sequence, forming a square D with its center located on the axis of the upper end face of the vibration isolation platform; The lower end surface of the vibration isolation platform is provided with ninth to twelfth threaded blind holes respectively matched with the connecting columns of the ninth to twelfth piezoelectric actuators, and the axes of the ninth to twelfth threaded blind holes correspond to each other and pass through the four vertices of the square D. The upper end surface of the vibration isolation platform is evenly provided with a number of fixed threaded blind holes for fixing to the outside world; The vibration isolation platform is arranged in the shell, the lower end surface of which is parallel to the base, and the first to fourth side walls are parallel to the four side walls of the shell respectively in one-to-one correspondence; The four side walls of the housing are provided with first to eighth mounting through holes which are coaxially corresponding to the first to eighth threaded blind holes, and the base is provided with ninth to twelfth mounting through holes which are coaxially corresponding to the ninth to twelfth threaded blind holes; The first to twelfth piezoelectric actuators are arranged one by one between the first to twelfth threaded blind holes and the first to twelfth mounting through holes, and the pre-tightening bolts thereof are sequentially passed through the corresponding mounting through holes and the first to sixth piezoelectric ceramic sheets and then threadedly connected with the pre-tightening threaded blind holes on the beam body to tighten the first to sixth piezoelectric ceramic sheets; The connecting column is threadedly connected to the corresponding threaded blind hole, so that the end of the beam body away from the first piezoelectric ceramic sheet abuts against the vibration isolation platform; The sensing module includes first to fourth acceleration sensors, wherein the first and second acceleration sensors are both arranged on the outer wall of the shell, the first acceleration sensor is located at the midpoint between the pre-tightening bolts of the first and second piezoelectric actuators, and the second acceleration sensor is located at the midpoint between the pre-tightening bolts of the seventh and eighth piezoelectric actuators; the third acceleration sensor is arranged on the upper end surface of the base outside the first acceleration sensor, and is located on the symmetric plane between the pre-tightening bolts of the first and second piezoelectric actuators; the fourth acceleration sensor is arranged on the upper end surface of the base outside the second acceleration sensor, and is located on the symmetric plane between the pre-tightening bolts of the seventh and eighth piezoelectric actuators; The control module is electrically connected to the first to twelfth piezoelectric actuators and the first to fourth acceleration sensors respectively, and is used to control the first to twelfth piezoelectric actuators to work according to the sensing data of the first to fourth acceleration sensors to offset the vibration received by the vibration isolation platform.

2. The six-degree-of-freedom platform for active vibration isolation according to claim 1, characterized in that: The beam body is provided with an annular groove whose width gradually narrows from the outside to the inside, so that a flexible hinge is formed on the beam body to amplify the amplitude.

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