Two-degree-of-freedom piezoelectric actuator and method of driving

Abstract

This invention relates to a two-degree-of-freedom piezoelectric actuator and its driving method, belonging to the field of precision machinery. The piezoelectric actuator includes a W-shaped base, an optical shaft, a piezoelectric drive unit, linear bearing housing I, and linear bearing housing II. The piezoelectric drive unit includes a compliant mechanism and a piezoelectric ceramic plate assembly. Linear bearing housing I and linear bearing housing II are symmetrically arranged on the two side plates of the W-shaped base. The piezoelectric drive unit is U-shaped, and its lower part is connected to the W-shaped base by screws. The optical shaft is fitted into two symmetrically mounted linear bearings, passing through the piezoelectric drive unit and elastically contacting the drive foot of the piezoelectric drive unit. The piezoelectric ceramic plates are symmetrically attached in pairs to the left and right side walls of the piezoelectric drive unit and to both sides of the upper crossbeam. When the piezoelectric ceramic plate assembly is energized, the compliant mechanism is driven to deform, thereby driving the optical shaft to achieve two-degree-of-freedom motion. The advantages of this invention are: simple and compact structure, high motion resolution, and wide applicability in precision manufacturing, aerospace, and other fields.

Description

Technical Field

[0001] This invention relates to the field of mobile precision machinery, and in particular to a two-degree-of-freedom piezoelectric actuator and driving method. Background Technology

[0002] Precision machining and aerospace applications often require high-precision drive devices with multiple degrees of freedom. Traditional electromagnetic and hydraulic actuators are insufficient to meet these precision requirements. Piezoelectric actuators utilize the inverse piezoelectric effect of piezoelectric materials to convert electrical energy into mechanical energy, thereby achieving mechanical motion. Piezoelectric actuators offer advantages such as high motion resolution, fast response, simple structure, and no electromagnetic interference, making them an effective means of achieving precision motion. However, existing piezoelectric actuators often have only a single degree of freedom. Therefore, developing a precision drive device with multiple degrees of freedom is essential.

[0003] This patent, through the design of a piezoelectric drive unit structure and the application of piezoelectric ceramic sheets and the principle of stick-slip motion, has invented a two-degree-of-freedom piezoelectric actuator. The two-degree-of-freedom piezoelectric actuator designed in this patent has a more compact structure, overcoming the problems of large space occupation and difficult spatial arrangement associated with multiple single-degree-of-freedom actuators connected in series. Simultaneously, the two-degree-of-freedom actuation achieved through the piezoelectric drive unit has higher resolution, avoiding the problem of significant accumulation of motion errors when multiple single-degree-of-freedom actuators are connected in series, thus enabling it to meet the precision motion requirements of laser processing. Summary of the Invention

[0004] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0005] A two-degree-of-freedom piezoelectric actuator is characterized by comprising a W-shaped base (1), an optical axis (2), a linear bearing seat I (3), a linear bearing seat II (4), and a piezoelectric drive unit (5), wherein the piezoelectric drive unit (5) comprises a compliant mechanism and a piezoelectric ceramic sheet assembly;

[0006] The W-shaped base (1) includes a W-shaped base side plate I (1-1), a W-shaped base side plate II (1-2), a W-shaped base inner plate (1-3), a linear bearing seat guide hole (1-4), a linear bearing seat fixing hole (1-5), and a piezoelectric drive unit fixing hole (1-6); wherein the linear bearing seat guide hole (1-4) and the linear bearing seat connecting hole (1-5) are respectively provided on the W-shaped base side plate I (1-1) and the W-shaped base side plate II (1-2);

[0007] The piezoelectric driving unit (5) described above comprises a compliant mechanism and a piezoelectric ceramic sheet set; the compliant mechanism is in a "square-frame shape" and includes a first side wall (6-1), a cross beam (6-2), a second side wall (6-3) and a fixed beam (6-4); the first side wall (6-1), the cross beam (6-2), the second side wall (6-3) and the fixed beam (6-4) enclose the "square-frame shape" in clockwise order, wherein a connecting hole (6-5) for fixing the piezoelectric driving unit (5) is arranged on the fixed beam (6-4); a driving foot (6-6) for driving the optical axis (2) is arranged in the middle of the cross beam (6-2);

[0008] The piezoelectric ceramic sheet set described above comprises an upper piezoelectric ceramic sheet set (7-1), a first side piezoelectric ceramic sheet set (7-2), and a second side piezoelectric ceramic sheet set (7-3); wherein the upper piezoelectric ceramic sheet set (7-1) is symmetrically bonded to both sides of the cross beam (6-2), the first side piezoelectric ceramic sheet set (7-2) is symmetrically bonded to both sides of the first side wall (6-1), and the second side piezoelectric ceramic sheet set (7-3) is symmetrically bonded to both sides of the second side wall (6-3); in the W-shaped base (1) described above, a first W-shaped base side plate (1-1) and a second W-shaped base side plate (1-2) symmetrically arrange a first linear bearing seat (3) and a second linear bearing seat (4) through linear bearing seat connecting holes (1-5), an inner W-shaped base plate (1-3) is connected with the fixed beam (6-4) of the compliant mechanism by screws; the optical axis (2) is sleeved into the symmetrically installed first linear bearing seat (3) and second linear bearing seat (4), and simultaneously passes through the first W-shaped base side plate (1-1), the piezoelectric driving unit (5) and the second W-shaped base side plate (1-2), and is in elastic contact with the driving foot (6-6) of the compliant mechanism.

[0009] Another object of the present invention is to provide a driving method for a two-degree-of-freedom piezoelectric actuator, characterized by comprising the following steps:

[0010] a) After assembly is completed, a sawtooth electric signal with a symmetry of 100% is applied to the upper piezoelectric ceramic sheet set (7-1), the cross beam (6-2) of the compliant mechanism is driven by the upper piezoelectric ceramic sheet set (7-1) to generate deformation, according to the stick-slip motion principle, the driving foot (6-4) drives the optical axis (2) to move along the +y direction; a sawtooth electric signal with a symmetry of 0% is applied to the upper piezoelectric ceramic sheet set (7-1), and the optical axis (2) moves along the -y direction; repeating the above steps can realize bidirectional large-stroke linear movement;

[0011] b) Apply a 100% symmetry sawtooth electrical signal to side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). The side walls I (6-1) and II (6-3) of the compliant mechanism are deformed by the drive of side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). According to the principle of stick-slip motion, the driving foot (6-6) drives the optical axis (2) to rotate clockwise around the y-axis. Apply a 0% symmetry sawtooth electrical signal to side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). The optical axis (2) will rotate counterclockwise around the y-axis. Repeating the above steps can realize bidirectional large stroke rotational motion.

[0012] The beneficial effects of this invention are: the designed two-degree-of-freedom piezoelectric actuator has a more compact structure, overcoming the problems of large space occupation and difficult spatial arrangement when multiple single-degree-of-freedom actuators are used in series. At the same time, the two-degree-of-freedom actuation achieved through the piezoelectric actuation unit has higher resolution, avoiding the problem of large accumulation of motion errors when multiple single-degree-of-freedom actuators are used in series, thus enabling it to meet the precision motion requirements of laser processing and other applications. Attached Figure Description

[0013] The accompanying drawings are provided to further illustrate the invention and form part of this application. The illustrative examples and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention.

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0015] Figure 2 This is a schematic diagram of the W-shaped base structure of the present invention;

[0016] Figure 3 This is a schematic diagram of the compliant structure in the piezoelectric drive unit of the present invention;

[0017] Figure 4 This is a schematic diagram of the piezoelectric drive unit of the present invention;

[0018] Figure 5 This is a schematic diagram illustrating the linear working principle of the piezoelectric drive unit of the present invention;

[0019] Figure 6 This is a schematic diagram illustrating the working principle of the piezoelectric drive unit of the present invention.

[0020] In the figure: 1, W-shaped base I; 1-1, W-shaped base side plate I; 1-2, W-shaped base side plate II; 1-3, W-shaped base inner plate; 1-4, linear bearing seat guide hole; 1-5, linear bearing seat connecting hole; 1-6, piezoelectric drive unit connecting hole; 2, optical shaft; 3, linear bearing seat I; 4, linear bearing seat II; 5, piezoelectric drive unit; 6-1, side wall I; 6-2, cross beam; 6-3, side wall II; 6-4, fixed beam; 6-5, connecting hole; 6-6, driving foot; 7-1, upper piezoelectric ceramic sheet group; 7-2, side piezoelectric ceramic sheet group I; 7-3, side piezoelectric ceramic sheet group II. Detailed Description of the Embodiments

[0021] The detailed content and specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0022] With reference to Figure 1-4 , a two-degree-of-freedom piezoelectric driver is characterized by comprising a W-shaped base (1), an optical shaft (2), a linear bearing seat I (3), a linear bearing seat II (4) and a piezoelectric drive unit (5), wherein the piezoelectric drive unit (5) comprises a compliant mechanism and a piezoelectric ceramic sheet group;

[0023] The W-shaped base (1) comprises a W-shaped base side plate I (1-1), a W-shaped base side plate II (1-2), a W-shaped base inner plate (1-3), a linear bearing seat guide hole (1-4), a linear bearing seat fixing hole (1-5) and a piezoelectric drive unit fixing hole (1-6); wherein the linear bearing seat guide hole (1-4) and the linear bearing seat connecting hole (1-5) are respectively arranged on the W-shaped base side plate I (1-1) and the W-shaped base side plate II (1-2);

[0024] The piezoelectric drive unit (5) comprises a compliant mechanism and a piezoelectric ceramic sheet group; the compliant mechanism is in a shape of a "square frame", and comprises a side wall I (6-1), a cross beam (6-2), a side wall II (6-3) and a fixed beam (6-4); the side wall I (6-1), the cross beam (6-2), the side wall II (6-3) and the fixed beam (6-4) enclose the "square frame" in a clockwise direction, wherein the connecting hole (6-5) for fixing the piezoelectric drive unit (5) is arranged on the fixed beam (6-4); the driving foot (6-6) for driving the optical shaft (2) is arranged in the middle of the cross beam (6-2);

[0025] The piezoelectric ceramic sheet assembly includes an upper piezoelectric ceramic sheet assembly (7-1), a side piezoelectric ceramic sheet assembly I (7-2), and a side piezoelectric ceramic sheet assembly II (7-3); wherein, the upper piezoelectric ceramic sheet assembly (7-1) is symmetrically attached to both sides of the crossbeam (6-2), the side piezoelectric ceramic sheet assembly I (7-2) is symmetrically attached to both sides of the side wall I (6-1), and the side piezoelectric ceramic sheet assembly II (7-3) is symmetrically attached to both sides of the side wall II (6-3); in the W-shaped base (1), the W-shaped base side plate I (1-1) and the W-shaped base side plate II (1-2) Linear bearing seat I (3) and linear bearing seat II (4) are symmetrically arranged through the connecting hole (1-5) of the linear bearing seat. The inner plate (1-3) of the W-shaped base is connected to the fixed beam (6-4) of the compliant mechanism by screws. The optical shaft (2) is inserted into the two symmetrically installed linear bearing seats I (3) and linear bearing seat II (4), and passes through the side plate I (1-1) of the W-shaped base, the piezoelectric drive unit (5) and the side plate II (1-2) of the W-shaped base, and makes elastic contact with the drive foot (6-6) of the compliant mechanism.

[0026] refer to Figure 5 and Figure 6 A driving method for a two-degree-of-freedom piezoelectric actuator, characterized by comprising the following steps:

[0027] a) After assembly, apply a 100% symmetrical sawtooth electrical signal to the upper piezoelectric ceramic plate group (7-1). The crossbeam (6-2) of the compliant mechanism is deformed by the drive of the upper piezoelectric ceramic plate group (7-1). According to the principle of stick-slip motion, the driving foot (6-4) drives the optical axis (2) to move along the +y direction. Apply a 0% symmetrical sawtooth electrical signal to the upper piezoelectric ceramic plate group (7-1). The optical axis (2) moves along the -y direction. Repeating the above steps can realize bidirectional large-stroke linear motion.

[0028] b) Apply a 100% symmetry sawtooth electrical signal to side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). The side walls I (6-1) and II (6-3) of the compliant mechanism are deformed by the drive of side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). According to the principle of stick-slip motion, the driving foot (6-6) drives the optical axis (2) to rotate clockwise around the y-axis. Apply a 0% symmetry sawtooth electrical signal to side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). The optical axis (2) will rotate counterclockwise around the y-axis. Repeating the above steps can realize bidirectional large stroke rotational motion.

Claims

1. A two-degree-of-freedom piezoelectric actuator, characterized in that: Comprising a W-shaped base (1), an optical shaft (2), a linear bearing seat I (3), a linear bearing seat II (4) and a piezoelectric driving unit (5), wherein the piezoelectric driving unit (5) comprises a compliant mechanism and a piezoelectric ceramic sheet group; The W-shaped base (1) comprises a W-shaped base side plate I (1-1), a W-shaped base side plate II (1-2), an inner plate of W-shaped base (1-3), linear bearing seat guide holes (1-4), linear bearing seat fixing holes (1-5), and piezoelectric driving unit fixing holes (1-6); wherein the linear bearing seat guide holes (1-4) and the linear bearing seat connecting holes (1-5) are respectively arranged on the W-shaped base side plate I (1-1) and the W-shaped base side plate II (1-2); The piezoelectric driving unit (5) comprises a compliant mechanism and a piezoelectric ceramic sheet group; the compliant mechanism is in a "square-frame shape" and comprises a side wall I (6-1), a cross beam (6-2), a side wall II (6-3) and a fixing beam (6-4); the side wall I (6-1), the cross beam (6-2), the side wall II (6-3) and the fixing beam (6-4) enclose the "square-frame shape" clockwise, wherein a connecting hole (6-5) for fixing the piezoelectric driving unit (5) is arranged on the fixing beam (6-4); a driving foot (6-6) for driving the optical shaft (2) is arranged in the middle of the cross beam (6-2); The piezoelectric ceramic sheet group comprises an upper piezoelectric ceramic sheet group (7-1), a side piezoelectric ceramic sheet group I (7-2), and a side piezoelectric ceramic sheet group II (7-3); wherein the upper piezoelectric ceramic sheet group (7-1) is symmetrically pasted on both sides of the cross beam (6-2), the side piezoelectric ceramic sheet group I (7-2) is symmetrically pasted on both sides of the side wall I (6-1), and the side piezoelectric ceramic sheet group II (7-3) is symmetrically pasted on both sides of the side wall II (6-3); in the W-shaped base (1), the W-shaped base side plate I (1-1) and the W-shaped base side plate II (1-2) symmetrically arrange the linear bearing seat I (3) and the linear bearing seat II (4) through the linear bearing seat connecting holes (1-5), and the inner plate of W-shaped base (1-3) is connected with the fixing beam (6-4) of the compliant mechanism by screws; the optical shaft (2) is sleeved into the two symmetrically installed linear bearing seat I (3) and linear bearing seat II (4), and passes through the W-shaped base side plate I (1-1), the piezoelectric driving unit (5) and the W-shaped base side plate II (1-2) at the same time, and is in elastic contact with the driving foot (6-6) of the compliant mechanism.

2. The driving method of a two-degree-of-freedom piezoelectric actuator according to claim 1, characterized in that: Comprising the following steps: a) After assembly, a sawtooth electrical signal with a symmetry of 100% is applied to the upper piezoelectric ceramic sheet group (7-1), the cross beam (6-2) of the compliant mechanism is driven by the upper piezoelectric ceramic sheet group (7-1) to generate deformation, and according to the stick-slip motion principle, the driving foot (6-6) drives the optical shaft (2) to move along the +y direction; when a sawtooth electrical signal with a symmetry of 0% is applied to the upper piezoelectric ceramic sheet group (7-1), the optical shaft (2) moves along the -y direction; repeating the above steps can realize bidirectional large-stroke linear motion; b) Apply a 100% symmetry sawtooth electrical signal to side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). The side walls I (6-1) and II (6-3) of the compliant mechanism are deformed by the drive of side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). According to the principle of stick-slip motion, the driving foot (6-6) drives the optical axis (2) to rotate clockwise around the y-axis. Apply a 0% symmetry sawtooth electrical signal to side piezoelectric ceramic plate group I (7-2) and side piezoelectric ceramic plate group II (7-3). The optical axis (2) will rotate counterclockwise around the y-axis. Repeating the above steps can realize bidirectional large stroke rotational motion.

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