Piezoelectric multidirectional force sensor

Abstract

This invention discloses a piezoelectric multi-directional force sensor, belonging to the field of piezoelectric technology. The device includes: a cylindrical base plate, an elastic film, six sets of piezoelectric elements, and a cylindrical mass block; the cylindrical base plate and the cylindrical mass block are concentrically mounted with equal radial dimensions, and the bottom surface of the cylindrical base plate is a certain height away from the bottom surface of the cylindrical mass block. The elastic film is adhered to the cylindrical cavity formed by the cylindrical mass block and the supporting cylindrical block, and the elastic film is filled with water. The six sets of piezoelectric elements are all made of PVDF material and are evenly adhered to the outer side of the elastic film. Under the excitation of an external force in any direction, the water placed inside the elastic film vibrates, deforming the elastic film radially, causing the six sets of piezoelectric elements to deform and generating six sets of equal-amplitude voltage change signals. This invention utilizes the positive piezoelectric effect to convert the measured pressure into electrical energy. By decoupling and observing the voltage change signals, the direction and magnitude of the measured pressure are analyzed, simplifying the structure of the force measuring device and optimizing the force measurement direction.

Description

Technical Field

[0001] This invention relates to a piezoelectric device, and more particularly to a piezoelectric multi-directional force sensor, belonging to the field of piezoelectric technology. Background Technology

[0002] A piezoelectric force sensor, or simply piezoelectric sensor, works on the principle that when an external force is applied along its sensitive axis, the measured pressure is converted into electrical energy based on the piezoelectric effect. Therefore, the external force can be determined by observing the voltage change.

[0003] Most conventional piezoelectric force sensors can only measure unidirectional external forces, and they have difficulty distinguishing the directions of the component forces of the resultant force when faced with a combination of external forces. Summary of the Invention

[0004] The purpose of this invention is to provide a piezoelectric multi-directional force sensor, which aims to solve the problem of traditional piezoelectric force sensors having only one force measurement direction.

[0005] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A piezoelectric multi-directional force sensor, characterized in that it comprises: a cylindrical base plate, an elastic thin film, six sets of piezoelectric plates, and a cylindrical mass block;

[0007] The piezoelectric multi-directional force sensor is characterized in that: the cylindrical base plate and the cylindrical mass block are concentrically mounted with equal radial dimensions; the bottom surface of the cylindrical base plate is a certain height away from the bottom surface of the cylindrical mass block; an elastic film is pasted into the cylindrical cavity formed by the cylindrical mass block and the supporting cylindrical block; the elastic film is filled with water; and six sets of piezoelectric sheets are all made of PVDF material and are circumferentially pasted onto the outside of the elastic film.

[0008] The force measurement method of this piezoelectric multi-directional force sensor is as follows:

[0009] Under the excitation of the vertical component of the external force, the water placed in the elastic membrane vibrates and deforms along the radial direction by equal amplitude compression of the elastic membrane, causing the six sets of piezoelectric sheets to deform at equal amplitude, generating six sets of equal amplitude voltage change signals;

[0010] Under the excitation of the horizontal component of the external force, the water placed in the elastic membrane vibrates and deforms by squeezing the elastic membrane in a large amount along the direction of the horizontal component force, which causes a large strain difference between the two sets of piezoelectric sheets in this direction, generating a symmetrical voltage change signal.

[0011] This invention utilizes the positive piezoelectric effect to convert the measured pressure into electrical energy. By analyzing the voltage change signal obtained through decoupling, the direction and magnitude of the measured pressure are simplified, and the force measuring device structure is optimized. Attached Figure Description

[0012] The following is a drawing of a specific embodiment of the present invention. The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this application, are illustrative examples of the invention and are used to explain the invention, but do not constitute an improper limitation of the invention.

[0013] Figure 1 This is a schematic diagram of the overall appearance structure of a piezoelectric multi-directional force sensor according to the present invention;

[0014] Figure 2 This is a top view showing the distribution of the six piezoelectric elements of the present invention;

[0015] Figure 3 This is a comparison diagram of the deformation before and after stress on the present invention;

[0016] In the diagram: 1. Cylindrical base plate; 2. Elastic film; 3. Piezoelectric sheet; 4. Cylindrical mass block. Detailed Implementation

[0017] The following description, in conjunction with the accompanying drawings, further illustrates the detailed content of the present invention and its specific embodiments.

[0018] See Figures 1 to 2 As shown, a piezoelectric multi-directional force sensor includes: a cylindrical base plate 1, an elastic film 2, piezoelectric sheets 3, and a cylindrical mass block 4; the cylindrical base plate 1 and the cylindrical mass block 4 have the same diameter and are concentrically mounted, the upper bottom surface of the cylindrical base plate 1 is a certain height away from the lower bottom surface of the cylindrical mass block 4, the elastic film 2 is pasted in the cylindrical cavity formed by the cylindrical base plate 1 and the cylindrical mass block 4, the elastic film 2 is filled with water, and six sets of piezoelectric sheets 3 are made of PVDF and are pasted on the outside of the elastic film 2 in a 60° circumference, with a certain gap between each set.

[0019] See Figure 3 As shown, under the excitation of the Z-direction external force, the water placed in the elastic film 2 vibrates and deforms along the radial direction by equal amplitude compression of the elastic film 2, causing the six sets of piezoelectric sheets 3 to undergo equal amplitude deformation as shown in Figure AA, generating six sets of equal amplitude voltage change signals;

[0020] See Figure 3 As shown, under the excitation of an external force with a certain angle to the X, Y, and Z axes, the water placed in the elastic film 2 vibrates and deforms by squeezing the elastic film 2 in a large way along the XY plane component of the external force. This causes a large strain difference between the two sets of piezoelectric plates 3-1 and 3-4 in this direction, generating six sets of voltage change signals symmetrically distributed with the voltage change signal of 3-4 as the peak.

[0021] The present invention can further improve the sensitivity of the force sensor by changing the number of piezoelectric elements, but too many piezoelectric elements will result in the strain signal of each group being indistinct. Therefore, the number of piezoelectric elements should be controlled within a reasonable range for application.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made to the present invention should be included within the scope of protection of the present invention.

Claims

1. A piezoelectric multi-directional force sensor, characterized in that: include: A cylindrical base plate (1), an elastic film (2), piezoelectric sheets (3), and a cylindrical mass block (4) are arranged. The cylindrical base plate (1) and the cylindrical mass block (4) are of equal diameter and are installed concentrically. The upper bottom surface of the cylindrical base plate (1) is a certain height away from the lower bottom surface of the cylindrical mass block (4). The elastic film (2) is pasted in the cylindrical cavity formed by the cylindrical base plate (1) and the cylindrical mass block (4). The elastic film (2) is filled with water. Six sets of piezoelectric sheets (3) are made of PVDF material and are pasted on the outside of the elastic film (2) in equal circumferences. There is a certain gap between each set. Under the excitation of external force in any direction, the water placed in the elastic film (2) vibrates and squeezes the elastic film (2) to deform. This causes the six sets of piezoelectric sheets (3) evenly distributed in the radial direction to be deformed by pressure, generating six sets of voltage change signals.

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