Large-step impact inertia piezoelectric driver and driving method thereof

Abstract

The present application relates to a kind of big step distance impact inertia piezoelectric driver and its driving method, belong to precision machinery field.The driving device includes basic unit, drive unit and guide rail slider, drive unit is a flexible hinge mechanism with rhombus displacement amplification mechanism, via screw and slider connection;Piezoelectric stack is embedded in rhombus displacement amplification mechanism.The driving method of the device is: when continuous sawtooth-shaped driving voltage is applied to piezoelectric stack, square wave voltage is applied to electromagnet and it is energized, de-energized operation, based on inertia impact principle, the impact inertia force that main mass block is subjected to is greater than the maximum static friction between it and friction block, slider will generate linear step movement.The advantage is: simple structure, strong driving capacity, high amplification ratio, can realize high speed large process, enhance its applicability in precision machinery and instrument, micro-nano operation and other fields.

Description

Technical Field

[0001] This invention relates to the field of precision machinery, and specifically designs a large-step impact inertial piezoelectric actuator and method, which can be used in precision / ultra-precision machining, precision optics and instruments, micromanipulation, aerospace and other fields. Background Technology

[0002] Piezoelectric actuation technology is a precision actuation technology based on the inverse piezoelectric effect of piezoelectric materials to control their mechanical deformation and thus output force and displacement. It features high precision, fast response, simple and flexible structure, and easy control, and has important applications in precision optical instruments, nanotechnology, precision machinery and instruments, and other fields. There are various types of piezoelectric actuation devices, currently mainly including inchworm-type, adhesive-slip, ultrasonic, and inertial types. Inchworm-type piezoelectric actuators have high motion resolution and large output load, but their complex structure requires multiple signal drives, making them unsuitable for space-constrained applications. Adhesive-slip piezoelectric actuators have relatively simple structure and control, and are more flexible in design, but the output displacement exhibits backlash, and the output force is low. Ultrasonic actuators have fast motion speed and large output load, but because they operate in a resonant state, their resolution and positioning accuracy are relatively low, making them unsuitable for applications requiring high positioning accuracy and resolution. Inertial motion principles are further divided into frictional inertial principles and impact inertial principles, both characterized by their simple structure. Inertial actuators, due to their long-distance, ultra-precision, and miniaturized characteristics, have found wide application in fields such as microsurgical microscopes, semiconductor manufacturing, and precision optical alignment. However, the inertial principle, due to its driving characteristics, requires overcoming friction to generate motion, thus affecting efficiency and stroke. Therefore, developing a stable, long-stroke, high-speed, high-load, and structurally simple inertial piezoelectric actuator remains a challenge. Summary of the Invention

[0003] The purpose of this invention is to provide a large-step impact inertial piezoelectric actuator, solving the aforementioned problems of the prior art. This invention mounts an electromagnet at the lower end of the inertial mass block of an asymmetric flexible hinge mechanism to generate magnetic force during motion. Based on the principle of inertial impact, this achieves a large-step stable output from the piezoelectric actuator. The device is simple to control; large-step linear motion can be achieved through a continuous sawtooth-shaped drive voltage, and reverse motion is achieved by applying a directional sawtooth-shaped drive voltage. The large-step impact inertial piezoelectric actuator of this invention has advantages such as simple structure, ease of manufacturing, simple control, and low cost, and can achieve stable, high-speed, bidirectional, large-stroke, and high-load continuous linear stepping motion.

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

[0005] A large-step impact inertial piezoelectric actuator, characterized in that it includes a base unit, a drive unit, and a guide rail slider 7; the base unit includes a steel base 4, a pre-tightening platform 5, friction blocks 6, and a boss 8; the drive unit includes a flexible hinge mechanism 1, a piezoelectric stack 2, and an electromagnet 3; the guide rail slider includes a guide rail 7-1 and a slider 7-2; wherein the boss is installed in the middle of the steel base by screws, the pre-tightening platforms I 5-1 and II 5-2 are stacked and installed at both ends of the steel base, the friction blocks I 6-1 and II 6-1 are respectively installed on the pre-tightening platforms I 5-1 and II 5-2 by screws, the guide rail 7-1 is fixed to the boss 8 by screws, and the slider 7-2 can slide on the guide rail; adjusting the knobs of the pre-tightening platforms I 5-1 and II 5-2 can adjust the contact force between the flexible hinge mechanism 1 and the friction blocks I 6-1 and II 6-1;

[0006] The flexible hinge 1 consists of three parts: a main mass block 1-1, a rhombic displacement amplification mechanism 1-2, and an inertial mass block 1-3, arranged sequentially along the x-axis. The flexible hinge mechanism 1 is in elastic contact with friction blocks I6-1 and II6-1 respectively through flexible drive feet I1-5-1 and flexible drive feet II1-5-2 symmetrically arranged on both sides of the main mass block 1-1. The electromagnet 3 is fixed to the inertial mass block 1-3 with screws through threaded mounting holes I1-4, and the normal pressure between it and the steel base is 0. The flexible hinge mechanism 1 is connected to the slider 7-2 with screws through threaded mounting holes II. The piezoelectric stack 2 is embedded in the rhombic displacement amplification mechanism 1-2.

[0007] Another object of the present invention is to provide a driving method for a large-step inertial piezoelectric actuator, comprising the following steps:

[0008] a) A sawtooth-shaped driving voltage with a symmetry of 60%-100% is applied to the piezoelectric stack 2. Simultaneously, high and low level signals are applied to the electromagnet during the experiment to energize and de-energize it. At time t0, both the piezoelectric stack driving voltage and the electromagnet signal are at a low level, and the entire mechanism remains unchanged. During the t0-t1 period, the piezoelectric stack voltage slowly increases, the piezoelectric stack 2 slowly elongates, and the rhomboid displacement amplification hinge 1-2 undergoes elastic deformation, causing the inertial mass block 1-5 and the electromagnet 3 to move a certain displacement along the +x direction. The main mass block 1-1 remains stationary under the action of the friction block 6. During the t0-T period, the electromagnet signal becomes high, the piezoelectric stack voltage drops rapidly, the piezoelectric stack 1-3 shortens rapidly, and the rhombic displacement amplification hinge 1-2 quickly returns to its initial state. Under the action of the magnetic force between the electromagnet 8 and the steel base 4, and the inertial force between the electromagnet 3 and the inertial mass block 1-3, the maximum static friction between the main mass block 1-1 and the friction block 6 is overcome, and the flexible hinge mechanism 1 drives the slider 7-2 to move a certain displacement along the positive x-axis. By repeating this process, continuous stepping motion along the positive x-axis can be achieved.

[0009] b) By adjusting the value and frequency of the driving voltage of the piezoelectric stack 2, its movement speed can be controlled.

[0010] c) Reverse motion can be achieved by applying a sawtooth wave driving voltage with a symmetry of 0%-40% to the piezoelectric stack 2 and adjusting the energizing time of the electromagnet.

[0011] The beneficial effects of this invention are: simple structure, easy to process and assemble, convenient control, and based on the principles of inertial impact and electromagnetic attraction, it can achieve large step size, stable, non-backward, high-speed continuous stepping motion. Attached Figure Description

[0012] 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.

[0013] Figure 1 This is an exploded view of the present invention;

[0014] Figure 2 This is a top view of the structure of the present invention;

[0015] Figure 3 This is a schematic diagram of the flexible hinge mechanism of the present invention.

[0016] Figure 4 This is a schematic diagram of the forward drive principle of the present invention;

[0017] Figure 5 This is the timing diagram of the reverse drive voltage of the present invention;

[0018] Figure 6 The actual motion output curve of the driving device of the present invention was measured when the driving voltage amplitude of the piezoelectric stack was 75 volts and there was no magnetic assistance.

[0019] In the diagram: 1. Flexible hinge mechanism; 1-1. Main mass block; 1-2. Rhomboid displacement amplification mechanism;

[0020] 1-3. Inertial mass block; 1-4. Threaded mounting hole I; 1-5. Flexible drive foot; 1-6. Threaded mounting hole II; 2. Piezoelectric stack; 3. Electromagnet; 4. Steel base; 5-1. Pre-tightening platform I; 5-2. Pre-tightening platform II; 6-1. Friction block I; 6-2. Friction block II; 7-1. Guide rail; 7-2. Slider; 8. Boss. Detailed Implementation

[0021] The following description, in conjunction with the accompanying drawings, further illustrates the detailed content of the present invention and its specific embodiments.

[0022] See Figure 1 , Figure 2 As shown, the large-step impact inertial piezoelectric actuator of the present invention is characterized by comprising a base unit, a drive unit, and a guide rail slider 7; the base unit comprises a steel base 4, a pre-tightening platform 5, a friction block 6, and a boss 8; the drive unit comprises a flexible hinge mechanism 1, a piezoelectric stack 2, and an electromagnet 3; the guide rail slider comprises a guide rail 7-1 and a slider 7-2.

[0023] See Figures 1 to 2 As shown, the boss is installed in the middle of the steel base by screws. Pre-tightening platforms I 5-1 and II 5-2 are stacked and installed at both ends of the steel base. Friction blocks I 6-1 and II (6-1) are respectively installed on the pre-tightening platforms I 5-1 and II 5-2 by screws. The guide rail 7-1 is fixed to the boss 8 by screws, and the slider 7-2 can slide on the guide rail. Adjusting the knobs of the pre-tightening platforms I 5-1 and II 5-2 can adjust the contact force between the flexible hinge mechanism 1 and the friction blocks I 6-1 and II 6-1.

[0024] See Figures 1 to 3 As shown, the flexible hinge 1 consists of three parts: a main mass block 1-1, a rhombic displacement amplification mechanism 1-2, and an inertial mass block 1-3, arranged sequentially along the x-axis. The flexible hinge mechanism 1 is in elastic contact with friction blocks I6-1 and II6-1 respectively through flexible drive feet I1-5-1 and flexible drive feet II1-5-2 symmetrically arranged on both sides of the main mass block 1-1. The electromagnet 3 is fixed to the inertial mass block 1-3 with screws through threaded mounting holes I1-4, and the normal pressure between it and the steel base is 0. The flexible hinge mechanism 1 is connected to the slider 7-2 with screws through threaded mounting holes II. The piezoelectric stack 2 is embedded in the rhombic displacement amplification mechanism 1-2.

[0025] See Figures 1 to 5 As shown, the control method of a large-step impact inertial piezoelectric actuator is specifically explained, including:

[0026] a) A sawtooth-shaped driving voltage with a symmetry of 60%-100% is applied to the piezoelectric stack 2. Simultaneously, high and low level signals are applied to the electromagnet during the experiment to energize and de-energize it. At time t0, both the piezoelectric stack driving voltage and the electromagnet signal are at a low level, and the entire mechanism remains unchanged. During the t0-t1 period, the piezoelectric stack voltage slowly increases, the piezoelectric stack 2 slowly elongates, and the rhomboid displacement amplification hinge 1-2 undergoes elastic deformation, causing the inertial mass block 1-5 and the electromagnet 3 to move a certain displacement along the +x direction. The main mass block 1-1 remains stationary under the action of the friction block 6. During the t0-T period, the electromagnet signal becomes high, the piezoelectric stack voltage drops rapidly, the piezoelectric stack 1-3 shortens rapidly, and the rhombic displacement amplification hinge 1-2 quickly returns to its initial state. Under the action of the magnetic force between the electromagnet 8 and the steel base 4, and the inertial force between the electromagnet 3 and the inertial mass block 1-3, the maximum static friction between the main mass block 1-1 and the friction block 6 is overcome, and the flexible hinge mechanism 1 drives the slider 7-2 to move a certain displacement along the positive x-axis. By repeating this process, continuous stepping motion along the positive x-axis can be achieved.

[0027] b) By adjusting the amplitude and frequency of the driving voltage of the piezoelectric stack 2, its movement speed can be controlled.

[0028] c) Reverse motion can be achieved by applying a sawtooth wave driving voltage with a symmetry of 0%-40% to the piezoelectric stack 2 and adjusting the energizing time of the electromagnet.

[0029] See Figure 6 The figure shows the actual motion output curves measured by this invention when the piezoelectric stack driving voltage amplitude is 75 volts, with and without magnetic assistance. When the electromagnet operates with magnetic assistance, the step size reaches 44 micrometers, while without magnetic assistance, the step size is only 20 micrometers.

[0030] The above description is merely a preferred embodiment of the present invention and is not limited to the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made to the present invention should be included within the scope of protection of the present invention.

Claims

1. A large-step impact inertial piezoelectric actuator, characterized in that: The system includes a base unit, a drive unit, and a guide rail slider (7). The base unit includes a steel base (4), a pre-tightening platform (5), a friction block (6), and a boss (8). The drive unit includes a flexible hinge mechanism (1), a piezoelectric stack (2), and an electromagnet (3). The guide rail slider includes a guide rail (7-1) and a slider (7-2). The boss is installed in the middle of the steel base by screws. The pre-tightening platform I (5-1) and the pre-tightening platform II (5-2) are symmetrically installed at both ends of the steel base. The friction block I (6-1) and the friction block II (6-2) are respectively installed on the pre-tightening platform I (5-1) and the pre-tightening platform II (5-2) by screws. The guide rail (7-1) is fixed on the boss (8) by screws. The slider (7-2) can slide on the guide rail. Adjusting the knobs of the pre-tightening platform I (5-1) and the pre-tightening platform II (5-2) can adjust the contact force between the flexible hinge mechanism (1) and the friction block I (6-1) and the friction block II (6-2). The flexible hinge mechanism (1) consists of three parts: a main mass block (1-1), a rhomboid displacement amplification mechanism (1-2), and an inertial mass block (1-3), and extends along... x The axes are arranged in sequence; the flexible hinge mechanism (1) is elastically contacted with friction block I (6-1) and friction block II (6-2) respectively by flexible drive feet I (1-5-1) and flexible drive feet II (1-5-2) symmetrically arranged on both sides of the main mass block (1-1); the electromagnet (3) is fixed to the inertial mass block (1-3) with screws through threaded mounting hole I (1-4), and the normal pressure between it and the steel base is 0; the flexible hinge mechanism (1) is connected to the slider (7-2) with screws through threaded mounting hole II; the piezoelectric stack (2) is embedded in the rhombic displacement amplification mechanism (1-2).

2. The driving method of a large-step impact inertial piezoelectric actuator according to claim 1, characterized in that: a) Apply a sawtooth driving voltage with a symmetry of 60%-100% to the piezoelectric stack (2), and simultaneously energize and de-energize the electromagnet by applying high and low level signals during the experiment; t At time 0, both the piezoelectric stack driving voltage and the electromagnet signal are at a low level, and the entire mechanism remains unchanged; t 0- t During period 1, the voltage of the piezoelectric stack slowly increases, the piezoelectric stack (2) slowly elongates, and the rhombic displacement amplification mechanism (1-2) undergoes elastic deformation, driving the inertial mass block (1-3) and the electromagnet (3) along + x Move a certain displacement; the main mass block (1-1) remains stationary under the action of the friction block (6); in t 0- T During this period, the electromagnet signal becomes high level, the piezoelectric stack voltage drops rapidly, the piezoelectric stack (2) shortens rapidly, and the rhombic displacement amplification mechanism (1-2) quickly returns to its initial state. Under the action of the magnetic force between the electromagnet (3) and the steel base (4) and the inertial force between the electromagnet (3) and the inertial mass block (1-3), the maximum static friction force between the main mass block (1-1) and the friction block (6) is overcome, and the flexible hinge mechanism (1) drives the slider (7-2) along the... x By moving the axis a certain distance in the positive direction and repeating this process, it is possible to achieve [the desired result] along [the axis]. x Continuous stepping motion in the positive axis direction; b) By adjusting the amplitude and frequency of the driving voltage of the piezoelectric stack (2), its movement speed can be controlled. c) By applying a sawtooth wave driving voltage with a symmetry of 0%-40% to the piezoelectric stack (2) and adjusting the energizing time of the electromagnet, reverse motion can be achieved.

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