Large-step impact inertia piezoelectric actuator and driving method thereof

Abstract

The invention relates to a large-step impact inertia piezoelectric actuator and a driving method thereof, and belongs to the field of precision machinery. The driving device comprises a basic unit, a driving unit and a guide rail sliding block, and the driving unit is a flexible hinge mechanism with a rhombic displacement amplifying mechanism and is connected with the sliding block through a screw; and the piezoelectric stack is embedded in the rhombic displacement amplification mechanism. The driving method of the device comprises the steps that when continuous zigzag driving voltage is applied to the piezoelectric stack, square waveform voltage is applied to the electromagnet to conduct power-on and power-off operation on the electromagnet, based on the inertial impact principle, the impact inertia force borne by the main mass block is larger than the maximum static friction force between the main mass block and the friction block, and the sliding block generates linear stepping motion. The invention has the advantages that the structure is simple, the driving capability is strong, the amplification ratio is high, the high-speed large process can be realized, and the applicability in the fields of precision machinery and instruments, micro-nano operation and the like is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of precision machinery, and particularly designs a large-step impact inertia piezoelectric driver and method, which can be used in the fields of precision / ultra-precision machining, precision optics and instruments, micromanipulation, aerospace, etc. Background Art

[0002] Piezoelectric drive technology is a precision drive technology that uses the inverse piezoelectric effect of piezoelectric materials to control their mechanical deformation and output force and displacement. It has the characteristics of high precision, fast response, simple and flexible structure, and simple control. It has important applications in the fields of precision optical instruments, nanotechnology, precision machinery and instruments. There are many types of piezoelectric drive devices, and the main types are inchworm type, stick-slip type, ultrasonic type, and inertial type. The inchworm type piezoelectric driver has high motion resolution and large output load, but its structure is complex and requires multi-channel signal drive, so it is not suitable for occasions with limited space. The stick-slip piezoelectric driver has a relatively simple structure and control, and the design is more flexible, but the output displacement has a setback and the output force is low. The ultrasonic driver has a fast motion speed and a large output load, but because it works in a resonant state, the resolution and positioning accuracy of this type of driver are low, and it is not suitable for occasions with high positioning accuracy and resolution requirements. The inertial motion principle is divided into two types: friction inertia principle and impact inertia principle, which have the characteristics of simple structure. Inertial actuators have been widely used in microsurgery microscopes, semiconductor manufacturing, precision optical alignment and other fields due to their long distance, ultra-precision and miniaturization. Due to its driving characteristics, the inertial principle needs to overcome friction to generate its own movement, so the efficiency and stroke will be affected to a certain extent. Therefore, it is still a difficult problem to develop a stable, large stroke, high speed, large load and simple structure inertial piezoelectric actuator. Summary of the invention

[0003] The purpose of the present invention is to provide a large-step impact inertia piezoelectric driver, which solves the above-mentioned problems existing in the prior art. The present invention installs an electromagnet at the lower end of the inertial mass block of an asymmetric flexible hinge mechanism in order to generate magnetic force during movement, and realizes a large-step stable output of the piezoelectric driver according to the inertial impact principle. The device is simple to control, and large-step linear motion can be achieved through a continuous sawtooth drive voltage, and reverse motion is achieved by applying a directional sawtooth drive voltage. The large-step impact inertia piezoelectric driver of the present invention has the advantages of simple structure, easy processing, simple control, and low cost, and can realize stable, high-speed, bidirectional, large-stroke, and large-load continuous linear stepping motion.

[0004] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0005] A large-step impact inertia piezoelectric driver, characterized in that it includes a basic unit, a driving unit, and a guide rail slider 7; the basic unit includes a steel base 4, a pre-tightening platform 5, a friction block 6, and a boss 8; the driving 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 platform I5-1 and the pre-tightening platform II5-2 are stacked and installed at both ends of the steel base, the friction block I6-1 and the friction block II (6-1) are respectively installed on the pre-tightening platform I5-1 and the pre-tightening platform II5-2 by screws, the guide rail 7-1 is fixed on the boss 8 by screws, and the slider 7-2 can slide on the guide rail; the knobs for adjusting the pre-tightening platform I5-1 and the pre-tightening platform II5-2 can adjust the contact force between the flexible hinge mechanism 1 and the friction block I6-1 and the friction block II6-1;

[0006] The flexible hinge 1 is composed of three parts, namely a main mass block 1-1, a rhombus displacement amplification mechanism 1-2 and an inertial mass block 1-3, and the parts are arranged in sequence along the x-axis; the flexible hinge mechanism 1 is in elastic contact with the friction block Ⅰ6-1 and the friction block Ⅱ6-1 respectively through the flexible driving feet Ⅰ1-5-1 and the flexible driving 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 by screws through the threaded mounting hole Ⅰ1-4, and the positive pressure between the electromagnet and the steel base is 0; the flexible hinge mechanism 1 is connected to the slider 7-2 by screws through the threaded mounting hole Ⅱ; the piezoelectric stack 2 is embedded in the rhombus displacement amplification mechanism 1-2.

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

[0008] a) Apply a sawtooth drive voltage with a symmetry of 60%-100% to the piezoelectric stack 2, and at the same time, during the test, apply high and low level signals to the electromagnet to power it on and off; at time t0, the piezoelectric stack drive voltage and the electromagnet signal are both low level, and the entire mechanism remains the same; during the t0-t1 period, the piezoelectric stack voltage rises slowly, the piezoelectric stack 2 slowly extends, and the diamond displacement amplification hinge 1-2 undergoes elastic deformation, driving 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 electrical signal becomes a high level, the piezoelectric stack voltage drops rapidly, the piezoelectric stack 1-3 shortens rapidly, and the diamond 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 direction of the x-axis. By repeating this process, continuous stepping motion along the positive direction of the x-axis can be achieved.

[0009] b) Adjusting the value and frequency of the driving voltage of the piezoelectric stack 2 can achieve the control of its movement speed

[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 period of the electromagnet.

[0011] The beneficial effects of the present invention are: simple structure, easy processing and assembly, convenient control, and based on the principle of inertial impact and electromagnetic attraction, it can achieve large step distance, stable, no retreat, high-speed continuous stepping motion; BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The illustrations of the drawings herein are used to provide further understanding of the present invention and constitute a part of this application. The illustrative examples of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0013] Figure 1 It is an explosion schematic diagram of the present invention;

[0014] Figure 2 It is a schematic diagram of the top view of the structure of the present invention;

[0015] Figure 3 The structural diagram of the flexible hinge mechanism of the present invention is

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

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

[0018] Figure 6 The actual motion output curve of the driving device of the present invention is measured when the amplitude of the piezoelectric stack driving voltage is 75 volts with or without magnetic assistance;

[0019] In the figure: 1, flexible hinge mechanism; 1-1, main mass block; 1-2, diamond displacement amplification mechanism;

[0020] 1-3, inertial mass block; 1-4, threaded mounting hole Ⅰ; 1-5, flexible driving foot; 1-6, threaded mounting hole Ⅱ; 2, piezoelectric stack; 3, electromagnet; 4, steel base; 5-1, preload platform Ⅰ; 5-2 preload platform Ⅱ; 6-1, friction block Ⅰ; 6-2, friction block Ⅱ; 7-1, guide rail; 7-2, slider; 8, boss. DETAILED DESCRIPTION

[0021] The details of the present invention and its specific implementation methods are further described below in conjunction with the accompanying drawings.

[0022] See also Figure 1 , Figure 2 As shown, the large-step impact inertia piezoelectric driver of the present invention is characterized by comprising a basic unit, a driving unit, and a guide rail slider 7; the basic unit comprises a steel base 4, a pre-tightening platform 5, a friction block 6, and a boss 8; the driving 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 also Figure 1 to Figure 2 As shown, the boss is installed in the middle of the steel base by screws, the pre-tightening platform I5-1 and the pre-tightening platform II5-2 are stacked and installed at both ends of the steel base, the friction block I6-1 and the friction block II (6-1) are respectively installed on the pre-tightening platform I5-1 and the pre-tightening platform II5-2 by screws, the guide rail 7-1 is fixed on the boss 8 by screws, and the slider 7-2 can slide on the guide rail; adjusting the knobs of the pre-tightening platform I5-1 and the pre-tightening platform II5-2 can adjust the contact force between the flexible hinge mechanism 1 and the friction block I6-1 and the friction block II6-1;

[0024] See also Figures 1 to 3 As shown, the flexible hinge 1 is composed of three parts: a main mass block 1-1, a rhombus displacement amplification mechanism 1-2 and an inertial mass block 1-3, and they are arranged in sequence along the x-axis; the flexible hinge mechanism 1 is in elastic contact with the friction block Ⅰ6-1 and the friction block Ⅱ6-1 respectively through the flexible driving feet Ⅰ1-5-1 and the flexible driving 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 by screws through the threaded mounting hole Ⅰ1-4, and the positive pressure between the electromagnet and the steel base is 0; the flexible hinge mechanism 1 is connected to the slider 7-2 by screws through the threaded mounting hole Ⅱ; the piezoelectric stack 2 is embedded in the rhombus displacement amplification mechanism 1-2.

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

[0026] a) Apply a sawtooth drive voltage with a symmetry of 60%-100% to the piezoelectric stack 2, and at the same time, during the test, apply high and low level signals to the electromagnet to power it on and off; at time t0, the piezoelectric stack drive voltage and the electromagnet signal are both low level, and the entire mechanism remains the same; during the t0-t1 period, the piezoelectric stack voltage rises slowly, the piezoelectric stack 2 slowly extends, and the diamond displacement amplification hinge 1-2 undergoes elastic deformation, driving 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 electrical signal becomes a high level, the piezoelectric stack voltage drops rapidly, the piezoelectric stack 1-3 shortens rapidly, and the diamond 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 direction of the x-axis. By repeating this process, continuous stepping motion along the positive direction of the 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 period of the electromagnet.

[0029] See also Figure 6 The figure shows the actual motion output curve of the present invention when the piezoelectric stack driving voltage amplitude is 75 volts with or without magnetic assistance. When the electromagnet works, that is, with magnetic assistance, the step distance reaches 44 microns, while without magnetic assistance, the step distance is only 20 microns.

[0030] The above description is only a preferred embodiment of the present invention and is not limited to the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the present invention shall be included in the protection scope of the present invention.

Claims

1. A large-step impact inertia piezoelectric actuator, characterized in that: The invention comprises a basic unit, a driving unit and a guide rail slider (7); the basic unit comprises a steel base (4), a pre-tightening platform (5), a friction block (6) and a boss (8); the driving 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); the boss is installed in the middle of the steel base by screws, and the pre-tightening platform I (5-1) and the pre-tightening platform II (5-2) are symmetrically installed on the steel base. At both ends of the steel base, friction blocks I (6-1) and friction blocks II (6-1) are respectively mounted on preload platforms I (5-1) and preload platforms II (5-2) by screws, a guide rail (7-1) is fixed on a boss (8) by screws, and a slider (7-2) can slide on the guide rail; adjusting the knobs of the preload platforms I (5-1) and the preload platforms II (5-2) can adjust the contact force between the flexible hinge mechanism (1) and the friction blocks I (6-1) and the friction blocks II (6-1); The flexible hinge (1) is composed of three parts, namely a main mass block (1-1), a rhombus displacement amplifying mechanism (1-2) and an inertial mass block (1-3), which are arranged in sequence along the x-axis; the flexible hinge mechanism (1) is in elastic contact with the friction block I (6-1) and the friction block II (6-1) respectively through the flexible driving feet I (1-5-1) and the flexible driving 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) by screws through the threaded mounting hole I (1-4), and the positive pressure between the electromagnet and the steel base is 0; the flexible hinge mechanism (1) is connected to the slider (7-2) by screws through the threaded mounting hole II; and the piezoelectric stack (2) is embedded in the rhombus displacement amplifying mechanism (1-2).

2. The driving method of a large-step impact inertia piezoelectric actuator according to claim 1, characterized in that: a) applying a sawtooth driving voltage with a symmetry of 60%-100% to the piezoelectric stack (2), and applying high and low level signals to the electromagnet to power it on and off during the test; at time t0, the piezoelectric stack driving voltage and the electromagnet signal are both at low levels, and the entire mechanism remains the same; during the t0-t1 period, the piezoelectric stack voltage slowly rises, the piezoelectric stack (2) slowly extends, and the diamond displacement amplification hinge (1-2) undergoes elastic deformation, driving 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) is on the friction block (6) In the period t0-T, the electromagnet electric signal changes to a high level, the piezoelectric stack voltage drops rapidly, the piezoelectric stack (1-3) shortens rapidly, the rhombus displacement amplifying hinge (1-2) returns rapidly to the initial state, and 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 direction of the x-axis, and repeats the process to achieve continuous stepping motion along the positive direction of the x-axis; b) By adjusting the amplitude and frequency of the driving voltage of the piezoelectric stack (1-4), the movement speed thereof can be controlled. c) Reverse motion can be achieved by applying a sawtooth wave driving voltage with a symmetry of 0%-40% to the piezoelectric stack (1-4) and adjusting the energization time period of the electromagnet.

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