CN101412020B - Composite Broadband Actuator System and Its Actuator - Google Patents

Abstract

The invention relates to a composite broadband actuator system and its actuator, belonging to the technical field of active control or new actuators. The system is characterized in that: the voltage input signal (1) is sequentially connected with the signal input circuit (2) and the frequency divider (3), wherein the output terminal of the frequency divider (3) is divided into two branches; one branch passes through the voltage divider The electric power amplifier (4) is connected to the piezoelectric actuator; the other branch is connected to the electromagnetic actuator through the electromagnetic power amplifier (5); (8) connected. The composite broadband actuator includes an electromagnetic actuator, and is characterized in that a piezoelectric actuator is compounded on the output shaft of the electromagnetic actuator. The invention combines the two with corresponding frequency division and drive circuits, fully utilizes the advantages of the two actuators, and expands their working frequency bands.

Description

Compound Broadband Actuator System and Its Actuator

technical field

The invention relates to a composite broadband actuator system and its actuator, belonging to the technical field of active control or new actuators. the

Background technique

As one of the important branches in the field of vibration control, active vibration control has developed rapidly, and has achieved incomparable effects in many occasions such as precision instruments, aerospace, transportation, and machinery. Actuators, also known as actuators, are key parts of active control systems. The role of the actuator is to exert control force on the control object according to the determined control law, so as to change the response of the system in the desired way. Traditional actuators include liquid actuation, gas actuation, electrical actuation, electromagnetic actuation, etc. Although they have a large working stroke, high motion speed and carrying capacity, they have large volume and weight and low resolution. High, narrow dynamic response range. Intelligent actuators based on smart materials, including actuators made of piezoelectric ceramics, piezoelectric films, shape memory alloys, magnetostrictive alloys, and electrorheological fluids. Among these intelligent material actuators, piezoelectric actuators have the advantages of wide frequency response range, fast response speed, high precision, and low energy consumption, but they are usually only suitable for high-frequency driving and have small output displacements. As the requirements for vibration control of objects increase, the requirements for actuators are also getting higher and higher. Both traditional and new actuators have their own shortcomings and cannot meet the needs of wide-frequency control. Considering that the characteristic of structural vibration is that it has a large amplitude in the low frequency band and a small amplitude in the high frequency band, the same is required for the actuator in order to realize the active control of vibration. Therefore, the basic idea of the present invention is to combine the low-frequency large-displacement electromagnetic actuator and the high-frequency small-displacement piezoelectric actuator through a special structure to obtain a broadband composite type that can respond from low frequency to high frequency range. actuator. the

Contents of the invention

When the electromagnetic actuator works in the low frequency band, it has good response characteristics and large output displacement. Due to its own structural characteristics that limit the upper limit frequency of its work, it is difficult to adapt to occasions that require high frequency actuation, while piezoelectric actuation When the actuator works in the high frequency band, it has fast response and high output displacement precision, which makes up for the deficiency of the electromagnetic actuator. The invention utilizes the advantages of the two, combines the two, provides a composite broadband actuator system and the actuator, and expands its working frequency band. the

A broadband composite actuator system, characterized in that: the voltage output line is connected to the signal input circuit and the frequency divider in turn, wherein the output end of the frequency divider is divided into two branches; one branch passes through the piezoelectric power amplifier and the frequency divider. The piezoelectric actuator is connected; the other branch is connected with the electromagnetic actuator through the electromagnetic power amplifier; the piezoelectric actuator and the output signal of the electromagnetic actuator are superimposed and then connected to the output terminal. the

A composite broadband actuator, including an electromagnetic actuator, is characterized in that: a piezoelectric actuator is compounded on the output shaft of the electromagnetic actuator; the connecting rod connected with the piezoelectric actuator serves as the The total displacement output of the compound actuator. the

A broadband composite actuator system of the present invention includes a signal input circuit, a frequency divider, a piezoelectric power amplifier, an electromagnetic power amplifier, and composite moving parts. The composite moving parts include piezoelectric actuators and movable coils. The signal input circuit transmits the broadband voltage signal to the input terminal of the frequency divider. The electric actuator provides the excitation signal, and the electromagnetic power amplifier provides the excitation signal for the movable coil. The output displacement of the composite actuator is the superposition of the respective output displacements of the piezoelectric actuator and the movable coil. When the frequency of the input signal is low, the output of the composite actuator is dominated by the large displacement output by the movable coil, and the output displacement of the piezoelectric actuator is almost negligible; when the input signal is a high-frequency signal, the composite actuator The output of the piezoelectric actuator is mainly the output of the piezoelectric actuator. The above broadband composite actuator can meet the different actuation requirements of the active vibration control for the actuator in the low frequency band and the high frequency band, so that the entire actuation system can be effectively controlled. the

General random vibration signals are broadband signals, the vibration amplitude in the low frequency band is larger, and the vibration amplitude in the high frequency band is smaller. The function of the frequency divider is to divide the input signal into two or more frequency bands, and use suitable actuators for different frequency bands, so as to maximize the advantages of each actuator. The frequency divider is realized by the principle of filtering. The input signal is passed through a low-pass filter to obtain a low-frequency signal, and after passing through a high-pass filter, a high-frequency signal is obtained. the

The function of power amplification is to amplify the input small signal to current or (and) voltage, so that it has enough energy to push the actuating element behind. In the higher voltage input range, the output displacement of the piezoelectric material has a linear relationship with the input voltage, so it is necessary to properly amplify the high-frequency signal obtained after frequency division. The actuating force and current of the movable coil have a linear relationship, so it is necessary to properly amplify the current of the low-frequency signal obtained after frequency division in order to meet the actuating requirements of the movable coil. the

The piezoelectric actuator is one of the core components of the actuator in the present invention, and its driving force is mainly generated by using the inverse piezoelectric effect of the piezoelectric material. The inverse piezoelectric effect means that a voltage is applied in the polarization direction of the piezoelectric element. Due to the action of the electric field, the positive and negative charge centers inside the piezoelectric element are relatively displaced, resulting in deformation of the piezoelectric element. That is to say, the piezoelectric material is made into the actuating element, and the electrical energy is converted into mechanical energy by applying an external electric field, and the displacement is output to form the actuating force. The basis for selecting the piezoelectric material is its performance parameters. For the piezoelectric actuator used in the present invention, the piezoelectric material with a larger piezoelectric strain constant can be selected. the

When a current is applied to the movable coil, it is subjected to the Lorentz force, resulting in a displacement. The magnitude of the Lorentz force is related to the number of turns, diameter, magnetic field strength and current of the coil. The magnetic field is generated by a permanent magnetic material and forms a closed magnetic circuit through a soft magnet. The invention realizes the displacement control of the movable coil by controlling the current. the

The coil support and the piezoelectric actuator are an integral structure. Since the movable coil itself has a large mass, it forms a low-pass displacement response structure with the leaf spring. When the piezoelectric part generates high-frequency vibration, the coil at the bottom is almost in a static state, so the piezoelectric actuator The output displacement is all reflected in the output end of the connecting rod. In order to prevent the coil support from rubbing or colliding with the magnetic material of the actuator when reciprocating in the axial direction, a leaf spring is used to provide the restoring force. Combining the respective advantages of piezoelectric actuation and electromagnetic actuation, the wide-band composite actuator can realize accurate and rapid control of the controlled object, especially suitable for work that requires a wide operating frequency band and high positioning accuracy occasion. the

Description of drawings

Figure 1 is a schematic diagram of the broadband compound actuator system. the

Figure 2 is a structural diagram of a broadband compound actuator. the

Explanation of symbols in the accompanying drawings: A. Composite actuator, 1. Voltage input signal, 2. Signal input circuit, 3. Frequency divider, 4. Piezoelectric power amplifier, 5. Electromagnetic power amplifier, 6. Piezoelectric Actuator, 7. Movable coil, 8. Output displacement, 9. Base, 10. Coil winding, 11. Coil support, 12. Leaf spring, 13. Connecting rod, 14. Piezoelectric tube, 15. Permanent magnet, 16. Soft magnets. the

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Fig. 1 is a schematic diagram of a broadband composite actuator system. The broadband composite actuator system of the present invention includes a voltage input signal 1, a signal input circuit 2, a frequency divider 3, a piezoelectric power amplifier 4, and an electromagnetic power Amplifier 5, composite actuator A. Among them, the voltage input signal 1, the signal input circuit 2, the frequency divider 3, the piezoelectric power amplifier 4 and the electromagnetic power amplifier 5 are located on the periphery of the composite actuator A, and the broadband random voltage signal input from the outside is connected to the signal through the signal input circuit 2. To the input terminal of the frequency divider 3, the frequency divider 3 passes the signal through a low-pass filter and a high-pass filter respectively, and divides the signal into two parts, the low frequency band and the high frequency band. The low-frequency output signal generated by the frequency divider 3 is connected to the input end of the electromagnetic actuation power amplifier 5 , and the high-frequency output signal is connected to the input end of the piezoelectric power amplifier 4 . The composite actuator A includes a piezoelectric actuator 6 and a movable coil 7. The piezoelectric power amplifier 4 amplifies the high-frequency voltage signal and transmits it to the input terminal of the piezoelectric actuator 6. The electromagnetic power amplifier 5 converts the low-frequency voltage signal to the input terminal of the piezoelectric actuator 6. After the signal is amplified into a large current signal, it is transmitted to the input end of the movable coil 7 . the

Figure 2 is a structural diagram of a broadband composite actuator, the base 9 fixes the entire composite actuator device, the permanent magnet 15 is fixed on the axis of the actuator, and the coil support 11 is located between the permanent magnet 15 and the soft magnet 16, The coil winding 10 is fixed on the coil support 11, the piezoelectric cylinder 14 and the coil support 11 are fixed together, the leaf spring 12 is fixed between the piezoelectric cylinder 14 and the casing, and the connecting rod 13 connected with the piezoelectric cylinder 14 is a composite actuator output terminal. the

The broadband composite actuation system of the invention combines the advantages of electromagnetic actuation and piezoelectric actuation, so that the output characteristics of the composite actuator are good in both low frequency and high frequency ranges. For a single movable coil, the output stroke is large in the low-frequency range, but the high-frequency response performance is not good; for a single piezoelectric actuator, the output displacement is small in the low-frequency range, but the ability to follow the signal is strong in the high-frequency range. Therefore, first of all, the input signal is properly divided by the frequency divider, so as to be respectively sent to the corresponding actuators for actuation, and strive to make the movable coil and piezoelectric actuation show good dynamics in the low frequency and high frequency ranges respectively. Responsive performance. the

The present invention selects the movable coil, because the electromagnetic actuation is more simple and easy to obtain the power supply, and the controllability of the actuator is better than that of the pneumatic, hydraulic and other driving methods that are also used for outputting large strokes. The movable coil realizes energy conversion through the law of electromagnetic induction, and the output current signal of the electromagnetically actuated power amplifier is connected to the coil to make it move under the action of force in the magnetic field. The design requirements of coil position, aspect ratio and other parameters are to minimize the size and weight of the coil under the premise of providing the magnetic potential required for the work, so as to reduce the influence of coil heating and its own weight on the performance of the actuator. The magnetic material constituting the magnetic circuit should have high magnetic saturation density, magnetic permeability, low hysteresis loss and other characteristics to meet the requirements of electromagnetic actuation. The main purpose of the leaf spring 12 is to prevent the movable coil from colliding with the magnetically permeable material (permanent magnet and soft magnet) during the continuous reciprocating motion, and it can also provide certain support and protection for the piezoelectric tube. It has a stable effect and forms a spring-mass low-pass displacement response system together with the movable coil to isolate the displacement of the movable coil caused by the high-frequency vibration of the piezoelectric tube.

The piezoelectric actuator described in the present invention can be in the form of a hollow cylindrical piezoelectric actuator or a piezoelectric stack. Piezoelectric actuators mainly use the inverse piezoelectric effect of piezoelectric materials. The hollow cylindrical piezoelectric actuator is composed of a thin-walled metal cylindrical tube and a hollow cylindrical piezoelectric material pasted on it, and the outer surface of the metal cylindrical tube forms a small gap with the inner surface of the hollow piezoelectric material. Fit, and glue them together. Compared with other smart materials, the piezoelectric material hollow cylindrical actuator is more suitable as the piezoelectric actuator in the present invention. The voltage signal output by the piezoelectric power amplifier generates an electric field, which causes the relative movement of the positive and negative charge centers inside the piezoelectric ceramic, resulting in mechanical deformation, and the deformation has a good linear relationship with the input voltage. Although the piezoelectric strain relationship of the piezoelectric material is multi-dimensional, there are several piezoelectric constants, which piezoelectric constant should be selected according to the specific working mode of the piezoelectric actuator. If the piezoelectric hollow cylindrical structure is used, d ₃₁ produces displacement, if a piezoelectric stack structure is used, only d ₃₃ is used to produce displacement. In the specific implementation, a larger piezoelectric strain constant should be selected as much as possible to generate a larger displacement and action force. The displacement accuracy exhibited by the piezoelectric cylinder in the high-frequency band can make the compound actuator have a good control effect on the vibration signal in the high-frequency band.

Claims (5)

1. A composite broadband actuator system, characterized in that: the external voltage input signal (1) is connected to the signal input circuit (2) and the frequency divider (3) in turn, wherein the frequency divider (3) output terminal Divided into two branches; one branch is connected with the piezoelectric actuator through the piezoelectric power amplifier (4); the other branch is connected with the electromagnetic actuator through the electromagnetic power amplifier (5); the above-mentioned piezoelectric actuator is connected with the The output signals of the electromagnetic actuator are superimposed and connected to the output terminal (8). 2. A compound broadband actuator, comprising an electromagnetic actuator, is characterized in that: a piezoelectric actuator is also compounded on the output shaft of the electromagnetic actuator; the connecting rod connected to the piezoelectric actuator (13) As the total displacement output end of the composite actuator. 3. The composite broadband actuator according to claim 2, characterized in that: between the piezoelectric actuator and the shell of the composite broadband actuator, a sheet-shaped spring (12). 4. The composite broadband actuator according to claim 2, characterized in that: the piezoelectric actuator is a hollow cylindrical piezoelectric actuator or a piezoelectric stack. 5. The composite broadband actuator according to claim 2, characterized in that: the electromagnetic actuator consists of a base (9), a permanent magnet (15) installed on the base (9), and a permanent The magnet (15) is arranged opposite to the soft magnet (16), and the coil winding (10) is installed between the permanent magnet (15) and the soft magnet (16), wherein the coil winding (10) is supported by a coil bracket (11).

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