Low-oscillation impact inertia piezoelectric actuator and driving method thereof

Abstract

The invention relates to a low-oscillation impact inertia piezoelectric actuator and a driving method thereof, and belongs to the field of precision machinery. The impact inertia driver comprises a base unit, a driving unit and a guide rail sliding block. The driving unit is a flexible hinge mechanism with a rhombic displacement amplification mechanism and is connected with the guide rail sliding block through a screw; and the piezoelectric stack is embedded in the rhombic amplification mechanism. The driving method of the device comprises the steps that when continuous zigzag driving voltage is applied to the piezoelectric stack, certain 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 resultant force of impact inertia force and magnetic force is larger than the friction force between the flexible hinge mechanism and the friction block, and the sliding block generates linear stepping motion. The invention has the advantages of simple structure, easiness in processing, assembly and control, capability of realizing high-speed large-stroke and high-load output, and no rollback displacement. The method has good application prospects in the fields of micro-nano operation, precise instruments, precision machining and the like.

Description

Technical Field

[0001] The present invention relates to the field of precision machinery, and in particular to a low-oscillation impact inertia piezoelectric driver and a driving method thereof, which can be used in the fields of precision / ultra-precision machining, precision optics and instruments, micromanipulation, biomedical engineering, etc. Background Art

[0002] Driving devices with large stroke and high precision have very important applications and demands in both the scientific and industrial communities. Stepper piezoelectric precision driving devices have been widely used in many fields such as precision machining, micro-nano operation and precision instruments due to their advantages of high precision, fast response, simple structure and easy operation. This type of driving device can be mainly divided into inchworm type, stick-slip type, ultrasonic type and inertial type according to different working principles. Although the working principles are different, these piezoelectric driving devices all achieve the purpose of large stroke movement by accumulating step displacement. Inchworm type driving devices can usually provide a large output force, and the output displacement is stable and does not retreat, but its structure is complex and assembly is difficult, which limits its wide application. Stick-slip driving devices have a simpler structure, easier control and flexible design, but the output displacement may retreat and the output force is weak. Ultrasonic driving devices need to work in a resonant state, with complex design, low positioning resolution and accuracy, and contact between driving components will cause severe wear when running at high frequencies. While the inertial drive device has a relatively simple structure and control, most of them have problems with overturning moment and large-mass cantilever, resulting in unstable movement of the drive device. The several piezoelectric devices mentioned above often produce large vibrations during the driving process, which will affect the driving accuracy and shorten the service life of the equipment. Therefore, how to reduce the vibration generated by the piezoelectric drive during operation and develop a low-oscillation impact inertial piezoelectric drive with stability, large stroke, high speed, large load, simple structure, easy control, no overturning moment and large-mass cantilever problems is still a difficult point and a problem that urgently needs to be solved. Summary of the invention

[0003] The present invention aims to provide a low-oscillation impact inertia piezoelectric driver and a driving method thereof to solve the above-mentioned problems existing in the prior art. When a continuous sawtooth driving voltage is applied to the piezoelectric stack, a certain waveform voltage is applied to the electromagnet to power it on and off. Based on the inertial impact principle, the combined force of the impact inertial force and the magnetic force is greater than the friction between the flexible hinge mechanism and the friction block, and the slider will produce a stable, large-stroke linear stepping motion.

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

[0005] A low-oscillation impact inertia piezoelectric driver, characterized in that it includes a basic unit, a driving unit, and a guide rail slider; the guide rail slider includes a guide rail and a slider; the driving unit includes a flexible hinge mechanism, a piezoelectric stack, and an electromagnet; the basic unit includes a steel base, a pre-tightening platform, a friction block, and a boss; wherein the boss is fixedly installed in the middle of the steel base, the pre-tightening platform I and the pre-tightening platform II are symmetrically installed at both ends of the steel base, the friction block I and the friction block II are respectively fixed on the pre-tightening platform I and the pre-tightening platform II by screws, the guide rail is fixed on the boss, and the slider can move on the guide rail; adjusting the knobs of the pre-tightening platform I and the pre-tightening platform II can control the contact force between the flexible hinge mechanism and the friction block I and the friction block II;

[0006] The flexible hinge mechanism is composed of three parts: a main mass block, a diamond-shaped amplifying mechanism and an inertial mass block, and the parts are arranged in sequence along the x-axis; the flexible hinge mechanism is in elastic contact with the friction block I and the friction block II respectively through the flexible driving feet I and the flexible driving feet II symmetrically arranged on both sides of the main mass block; the electromagnet is fixed on the inertial mass block through the threaded mounting hole I, and the positive pressure between the electromagnet and the steel base is 0; the flexible hinge mechanism is fixed to the slider through the threaded mounting hole II; the piezoelectric stack is embedded in the diamond-shaped amplifying mechanism.

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

[0008] a) A sawtooth driving voltage with a symmetry of 60%-100% is applied to the piezoelectric stack of the driving unit, and during the test, high and low level signals are applied to the electromagnet to power it on and off; at time t0, the piezoelectric stack driving voltage and the electromagnet electrical signal are both at low levels, and the entire mechanism remains the same; at time t0-t1, the electromagnet electrical signal remains at a low level, the piezoelectric stack driving voltage rises slowly, the piezoelectric stack slowly stretches, and the diamond-shaped amplification mechanism undergoes elastic deformation, driving the inertial mass block and the electromagnet + When the slider moves in the x-direction, the main mass block remains stationary under the action of the friction block; at the moment t1-t2, the electromagnet electrical signal changes to a high level, the voltage of the piezoelectric stack drops rapidly, the piezoelectric stack shortens rapidly, and the diamond-shaped amplification mechanism elastically returns to its initial state quickly. Under the action of the magnetic force between the electromagnet and the steel base and the inertial force between the electromagnet and the inertial mass block, the maximum static friction between the main mass block and the friction block is overcome, and the flexible hinge mechanism drives the slider to move a certain distance in the positive direction of the x-axis; repeating this process can realize continuous stepping motion in the positive direction of the x-axis;

[0009] b) adjusting the driving voltage amplitude of the piezoelectric stack to achieve the control of the movement step; adjusting the driving frequency of the piezoelectric stack to achieve the control of the movement speed;

[0010] c) Reverse motion can be achieved by applying a sawtooth drive voltage with a symmetry of 0%-40% to the piezoelectric stack.

[0011] The beneficial effects of the present invention are: simple structure, through the low-oscillation impact inertia piezoelectric driver and its driving method provided by the present invention, the vibration in the driving process of the previous driver can be improved, the possibility of mass production is increased, and the driving accuracy and equipment stability of the driver are improved, and the application field and applicable occasions of the impact inertia piezoelectric driver are expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described 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 Shown is a schematic structural diagram of the present invention;

[0014] Figure 2 Shown is a schematic diagram of the structure explosion of the present invention;

[0015] Figure 3 Shown is a schematic structural diagram of the flexible hinge mechanism of the present invention;

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

[0017] Figure 5 The figure shows the relationship between the reverse motion sawtooth wave electrical signal waveform and the electromagnet energization electrical signal waveform of the present invention.

[0018] Among them: 1. Steel base; 2. Piezoelectric stack; 3. Flexible hinge mechanism; 3-1. Main mass block; 3-2. Diamond amplification mechanism; 3-3. Inertial mass block; 3-4. Threaded mounting hole I; 3-5. Flexible driving foot; 3-6. Threaded mounting hole II; 4-1. Preload platform I; 4-2. Preload platform II; 5-1. Friction block I; 5-2. Friction block II; 6. Boss; 7. Guide rail slider; 7-1. Guide rail; 7-2. Slider; 8. Electromagnet. DETAILED DESCRIPTION

[0019] The details of the present invention and its specific implementation methods are further described below in conjunction with the accompanying drawings.

[0020] See also Figure 1 , Figure 2As shown, the low oscillation impact inertia piezoelectric driver of the present invention includes a basic unit, a driving unit, and a guide rail slider 7; the guide rail slider 7 includes a guide rail 7-1 and a slider 7-2; the driving unit includes a flexible hinge mechanism 3, a piezoelectric stack 2 and an electromagnet 8; the basic unit includes a steel base 1, a pre-tightening platform 4, a friction block 5, and a boss 6.

[0021] See also Figure 1 to Figure 2 As shown, the boss is fixedly installed in the middle of the steel base, the pre-tightening platform Ⅰ4-1 and the pre-tightening platform Ⅱ4-2 are symmetrically installed at both ends of the steel base 1, the friction block Ⅰ5-1 and the friction block Ⅱ5-2 are respectively fixed on the pre-tightening platform Ⅰ4-1 and the pre-tightening platform Ⅱ4-2 by screws, the guide rail 7-1 is fixed on the boss 6, and the slider 7-2 can move on the guide rail 7-1; adjusting the knobs of the pre-tightening platform Ⅰ4-1 and the pre-tightening platform Ⅱ4-2 can control the contact force between the flexible hinge mechanism 3 and the friction blocks Ⅰ5-1 and the friction blocks Ⅱ5-2.

[0022] See also Figure 3 As shown, the flexible hinge mechanism 3 is composed of three parts: a main mass block 3-1, a diamond-shaped amplifying mechanism 3-2 and an inertial mass block 3-3, and they are arranged in sequence along the x-axis; the flexible hinge mechanism 3 is in elastic contact with the friction block Ⅰ5-1 and the friction block Ⅱ5-2 respectively through the flexible driving feet Ⅰ3-5-1 and the flexible driving feet Ⅱ3-5-2 symmetrically arranged on both sides of the main mass block; the electromagnet 8 is fixed to the inertial mass block 3-3 through the threaded mounting hole Ⅰ3-4, and the electromagnet 8 and the steel base 1 are very close to each other without contact, and no positive pressure is generated between the two; the flexible hinge mechanism 3 is fixed to the slider 7-2 through the threaded mounting hole Ⅱ3-6; the piezoelectric stack 2 is embedded in the diamond-shaped amplifying mechanism 3-2.

[0023] See also Figure 4 As shown, a control method of a low oscillation impact inertia piezoelectric actuator is specifically described, including:

[0024] a) A sawtooth driving voltage with a symmetry of 60%-100% is applied to the piezoelectric stack 2 of the driving unit, and at the same time, during the test, high and low level signals are applied to the electromagnet 8 to power it on and off; at time t0, the piezoelectric stack driving voltage and the electromagnet electrical signal are both low level, and the entire mechanism remains the same; at time t0-t1, the piezoelectric stack driving voltage rises slowly, and the electromagnet electrical signal is still at a low level. When the driving voltage rises slowly, the piezoelectric stack 2 slowly stretches, causing the flexible part of the diamond-shaped amplifying mechanism 3-2 with diamond displacement amplification to undergo elastic deformation. As the driving voltage increases, the elastic deformation of the diamond-shaped amplifying mechanism 3-2 increases, and the displacement of the inertial mass block increases; in the above process, due to the lack of The maximum static friction force that the friction block can withstand is reached, so the main mass block 3-1 remains stationary; at the moment t1-t2, the driving voltage of the piezoelectric stack drops rapidly, and the electromagnet electrical signal becomes a high level. When the driving voltage drops rapidly, the piezoelectric stack 2 shrinks rapidly, and the diamond-shaped amplifying mechanism 3-2 quickly and elastically returns to the initial state. At the same time, the high-level electrical signal causes the electromagnet 8 to generate a magnetic force in the positive direction of the x-axis. The positive magnetic force generated by the electromagnet 8 and the inertial impact force generated by the flexible hinge mechanism 3 in this process overcome the maximum static friction force between the main mass block 3-1 and the friction block 5, so that the flexible hinge mechanism 3 drives the slider 7-2 to move a certain distance along the positive direction of the x-axis; repeating this process can achieve continuous stepping motion along the positive direction of the x-axis;

[0025] b) adjusting the driving voltage amplitude and frequency of the piezoelectric stack 2 to control its movement speed;

[0026] c) Reverse motion can be achieved by applying a sawtooth wave driving voltage with a symmetry of 0%-40% to the piezoelectric stack 2.

Claims

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

2. The driving method of a low oscillation impact inertia piezoelectric actuator according to claim 1, characterized in that: The following steps are involved: a) applying a sawtooth driving voltage with a symmetry of 60%-100% to the piezoelectric stack (2) of the driving unit, and applying high and low level signals to the electromagnet (8) to power it on and off during the test; at time t0, the driving voltage of the piezoelectric stack and the electromagnet electrical signal are both at low levels, and the entire mechanism remains the same; at time t0-t1, the electromagnet electrical signal remains at a low level, the driving voltage of the piezoelectric stack rises slowly, the piezoelectric stack (2) slowly stretches, the diamond-shaped amplifying mechanism (3-2) undergoes elastic deformation, driving the inertial mass block and the electromagnet (8) to move in the +x direction, and the main mass block (3-1) moves in The piezoelectric stack (2) is kept stationary under the action of the friction block (5); at the moment t1-t2, the electromagnet electrical signal changes to a high level, the piezoelectric stack voltage drops rapidly, the piezoelectric stack (2) is shortened rapidly, and the diamond-shaped amplifying mechanism (3-2) quickly elastically returns to the initial state. Under the action of the magnetic force between the electromagnet (8) and the steel base (1) and the inertial force between the electromagnet (8) and the inertial mass block (3-3), the maximum static friction between the main mass block (3-1) and the friction block (5) is overcome, and the flexible hinge mechanism (3) drives the slider (7-2) to move a certain distance along the positive direction of the x-axis; repeating this process can realize continuous stepping motion along the positive direction of the x-axis; b) adjusting the driving voltage amplitude of the piezoelectric stack (2) to achieve the control of the movement step; By adjusting the driving frequency of the piezoelectric stack (2), the movement speed can be regulated; c) Reverse motion can be achieved by applying a sawtooth wave driving voltage with a symmetry of 0%-40% to the piezoelectric stack (2).

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