CN103323098A - Small-sized micro-vibration measurement and control system - Google Patents

Abstract

The invention relates to a small-scale micro-vibration measurement and control system, which includes: a base, a load plate, a folding beam, a piezoelectric sensor, a piezoelectric actuator, and a data processing and control system; the folding beam includes two beams, each A piezoelectric sheet is pasted on the upper and lower surfaces of each beam, the outer piezoelectric sheet is used as a piezoelectric actuator, and the inner layer of piezoelectric sheet is used as a piezoelectric sensor; the folded beam is located between the load plate and the base, and is connected by bolts. ; Four folded beams are evenly distributed along the circumference of the lower surface of the load plate, and the eight piezoelectric sensors distributed on it can measure three dynamic forces and three dynamic bending moments of the load disturbance source; each piezoelectric sensor measures After the signal is processed by the data processing and control system, a specific control voltage is output to the piezoelectric actuator juxtaposed with it, thereby realizing the suppression of load vibration; the invention can effectively measure the load vibration and suppress the transmission of the load vibration, and the reliability high.

Description

A small micro-vibration measurement and control system

technical field

The invention relates to a small-scale micro-vibration measurement and control system, which can be used for dynamic measurement of the vibration signal of the micro-disturbance load of the spacecraft component on six degrees of freedom and suppress the transmission of the vibration.

Background technique

Most of the current spacecraft are large-scale flexible deployment mechanisms with a large number of optical elements, which have high requirements for pointing accuracy and stability. In addition, in the attitude control system of modern spacecraft, reaction wheels, single-frame moment gyroscopes and solar wing drive mechanisms are important components in the control system. While they provide the necessary control power, they will also cause some harmful vibrations ( For simplicity, the above three systems are collectively referred to as disturbance sources below). These disturbances are mainly caused by flywheel unbalance, bearing disturbance, motor disturbance, motor drive error, etc. Among them, flywheel unbalance is the main cause of flywheel vibration, and these disturbance forces and disturbance moments will reduce the performance of precision instruments in body space Therefore, measuring and analyzing the dynamic characteristics of the spacecraft payload disturbance and controlling its vibration has very important engineering significance for improving the attitude control accuracy of the spacecraft and strengthening the safety design of the spacecraft.

Because the disturbance of the disturbance source of the spacecraft is very small, individual payloads such as momentum wheels can only produce weak disturbances of tens of millinewtons or even several millinewtons in three directions in space. It is very difficult to measure and control such disturbances, and the accuracy requirements of the corresponding sensors\actuators are very high.

At present, there is no literature report about this kind of micro-vibration measurement and control system at home and abroad.

Contents of the invention

The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art, to provide a small micro-vibration control system, which can suppress the transmission of vibration in space during the operation of spacecraft components, so as to improve the attitude control accuracy and Enhance the safety design of spacecraft.

The technical solution adopted by the present invention to solve the technical problem is: a small-scale micro-vibration measurement and control system, including: a base, a load plate, four folding beams, eight piezoelectric sensors, eight piezoelectric actuators, Sixteen bolts, eight through holes and data processing and control system; the load is mounted on the upper surface of the load plate; each piezoelectric folding beam contains two beams, two piezoelectric sensors and two piezoelectric actuators ; The piezoelectric folding beam is located between the upper surface of the base and the lower surface of the load plate, and is evenly distributed along the circumference of the lower surface of the load plate. The piezoelectric folding beam is connected to the load plate and the base through sixteen bolts; The Z axis in space is vertical, and two adjacent folded beams are perpendicular to each other; two piezoelectric sensors are pasted on the inside of each piezoelectric folded beam, which can measure the force and moment in the X, Y, and Z directions; each piezoelectric folded beam is glued on the outside There are two piezoelectric actuators, which are used to receive the output signals of the data processing and control system and generate force to suppress system vibration. After the vibration source or load generates vibration, the eight piezoelectric sensors will measure the vibration signal and input it into the data processing and control system in the form of voltage. The data processing and control system will invert and amplify the input signal with a specific gain and output it to the corresponding piezoelectric sensor. Actuator, finally realizing the transmission of suppressed load vibration.

The eight piezoelectric sensors and eight piezoelectric actuators are d ₃₁ piezoelectric ceramic elements.

The shape of the load plate is circular, and there are eight countersunk holes for connecting piezoelectric folding beams, and four bolt through holes for connecting loads.

The eight piezoelectric sensors are symmetrically distributed on the inner surface of the piezoelectric folding beam.

The eight piezoelectric actuators are symmetrically distributed on the outer surface of the piezoelectric folding beam.

The base is a square frame with four arc-shaped notches on the inner edge, eight countersunk holes on the frame for connecting piezoelectric folding beams, and four bolt through holes for connecting fixed ends.

Two pairs of piezoelectric sensors and piezoelectric actuators in each piezoelectric folding beam are aligned and juxtaposed (that is, each piezoelectric sensor and a piezoelectric actuator are arranged symmetrically along the upper and lower surfaces of the beam), which shortens the system response time, improved control performance.

The system can be used as a sensor when not outputting control signals to realize vibration measurement; when outputting control signals, it can be used as a controller to realize vibration suppression.

Compared with the prior art, the present invention has the following advantages:

(1) The present invention can effectively measure load vibration and suppress the transmission of load vibration, and has high reliability; and the present invention can be used as a sensor when the control system does not output control signals to realize micro-vibration signal measurement; when outputting control signals, it can be used as a sensor The controller is used to achieve vibration suppression.

(2) Two pairs of piezoelectric sensors and piezoelectric actuators in each piezoelectric folding beam in the present invention are respectively pasted on the upper and lower surfaces of the beam, and are used as sensors and actuators when the beam is deformed due to load disturbance The phase difference of the voltage signal generated on the piezoelectric ceramic sheet remains unchanged, and the feedback control rate can be directly used to realize vibration control, and the engineering application is relatively simple.

(3) In the present invention, the control device and the load are separated, no additional equipment and sensors need to be installed on the load, the dynamic characteristics of the load are not affected, and the structure of the load is not damaged.

(4) In the present invention, each piezoelectric sensor is aligned and juxtaposed with a piezoelectric actuator, and the signal of the piezoelectric sensor is directly output to the piezoelectric actuator by the control system after inverting and amplifying, which simplifies the control process. The system response time is shortened and the control performance is improved.

(5) The vibration control device of the present invention is small in size and flexible in installation form, and can be conveniently applied to various occasions, improving the applicability of the control system.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic structural view of the load plate in the present invention;

Fig. 3 is a schematic diagram of the base structure in the present invention;

Figure 4 is a comparison of the first-order modal response before and after system control under simple harmonic force excitation.

Labels in the figure: four load plate through holes 1, four base through holes 7, fastening bolts 2, load plate 3, four folding beams 4, piezoelectric actuator 5, base 6, piezoelectric sensor 8, beam 9. Data processing and control system 10.

Detailed ways

As shown in Figures 1, 2, and 3, a small-scale micro-vibration measurement and control system of the present invention includes: four load plate through holes 1, fastening bolts 2, load plate 3, four folding beams 4, piezoelectric actuation Device 5, base 6, four base through holes 7, piezoelectric sensor 8, beam 9 and data processing and control system 10; piezoelectric actuator 5 and piezoelectric sensor 8 are d ₃₁ type piezoelectric ceramic components, load The disk 3 is circular, as shown in Figure 2, there are eight countersunk holes on it for connecting the piezoelectric folding beams 4, and the four piezoelectric folding beams 4 are located between the upper surface of the base 6 and the lower surface of the loading disk 3 , evenly distributed along the circumference of the lower surface of the load plate 3, the base 6 is a square frame, as shown in Figure 3, there are four arc-shaped gaps on its inner edge, and eight sink holes on the frame are used to connect the piezoelectric folding Beam 4 and four base through holes 7 are used to connect fixed ends; outputs of eight piezoelectric sensors 8 and inputs of eight piezoelectric actuators 5 are connected to data processing and control system 10 through signal transmission lines.

In the implementation, the base 6 is an aluminum frame base, and the load plate 3 is also made of aluminum material. The base 6, the load plate 3 and the folding beam 4 need to be milled with positioning grooves for easy installation; the load passes through the four load plate through holes 1 using bolts It is fixed at the center of the upper surface of the load plate 3 . Four folded beams 4 equipped with piezoelectric sensors 8 and piezoelectric actuators 5 are evenly distributed on the lower surface of the load plate 3, and the edges of the folded beams 4 are aligned with the edges of the base 6; eight piezoelectric sensors 8 are used to measure the load vibration signal, eight piezoelectric actuators 5 generate control torque to suppress the transmission of load vibration.

The upper surface of the base 6 is connected with the folded beam 4, and the bottom is connected with the fixed end (foundation) with bolts through four base through holes 7 . The entire structure must ensure that its stiffness meets the requirements of dynamic testing.

Install the micro-vibration control system on the foundation, install the load micro-vibration source on the center of the load plate 3, check whether the signals of the piezoelectric sensors 8 on the four folded beams 4 are normal, and check the piezoelectric actuator 5 Response, and then run the load to make it vibrate, so that the eight piezoelectric sensors 8 generate voltage signals, and the voltage signals can be converted into three tiny The disturbance force signal and three small disturbance torque signals, the piezoelectric material force-electric conversion relationship is as follows:

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; ip</span>}}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}^{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; ,</span>$

${\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; pq</span>}}^{\mathrm{<span\; class="notranslate">\; E.</span>}}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

是常应力下介电常数，

为零电场下材料柔度，d是压电常数，i,j＝1,2,3和p,q＝1,2,...,6表示材料坐标系下不同的方向，本发明实施中取i＝3，p＝1。用于负载的振动控制时，数据处理和控制系统10根据采集到的扰动力信息通过线性二次最优（LQR）（或其他控制方法）控制率输出控制电压信号给压电作动器5，作动器5会产生相应的作动力作用于负载从而实现了对负载振动的控制。本系统中每一个压电折叠梁4中的两对压电传感器与压电作动器分别位于横梁9的上下表面，在由于负载扰动导致基梁变形时，用作传感器与作动器的压电陶瓷片上产生的电压信号的相位差保持不变，可直接使用反馈控制率实现振动控制，因此缩短了系统反应时间，提高了控制性能。此外，本发明中控制装置和被控试件分离，不需要在被控试件上安装附加设备和传感器，不影响被测试件的动态特性，不会损伤被测试件结构，可以方便的应用于多种场合，具有很强的适用性。where D _i is the electric displacement, σ is the stress, ε is the strain, E _f is the electric field,

is the dielectric constant under constant stress,

is the material compliance under zero electric field, d is the piezoelectric constant, i, j=1, 2, 3 and p, q=1, 2,..., 6 represent different directions under the material coordinate system, in the implementation of the present invention Take i=3, p=1. When used for load vibration control, the data processing and control system 10 outputs a control voltage signal to the piezoelectric actuator 5 through a linear quadratic optimal (LQR) (or other control method) control rate according to the collected disturbance force information, The actuator 5 will generate a corresponding dynamic force to act on the load so as to realize the control of the vibration of the load. The two pairs of piezoelectric sensors and piezoelectric actuators in each piezoelectric folding beam 4 in this system are respectively located on the upper and lower surfaces of the beam 9. When the base beam is deformed due to load disturbance, they are used as pressure sensors and actuators. The phase difference of the voltage signal generated on the electric ceramic chip remains unchanged, and the feedback control rate can be directly used to realize vibration control, thus shortening the system response time and improving the control performance. In addition, in the present invention, the control device and the controlled test piece are separated, no additional equipment and sensors need to be installed on the controlled test piece, the dynamic characteristics of the tested piece are not affected, the structure of the tested piece is not damaged, and it can be conveniently applied to It has strong applicability in many occasions.

If the system is only used as a piezoelectric sensor, since the voltage signal of the piezoelectric sensor 8 is obtained through the data acquisition and processing system, to convert the voltage signal into a force signal, the piezoelectric sensor 8 needs to be calibrated to obtain the corresponding sensitivity coefficient, which can be multiplied by the voltage signal to obtain the force signal of the payload.

The data processing and control system 10 is composed of a data acquisition box, a computer and a power amplifier. The data acquisition box converts the voltage signal obtained by the piezoelectric sensor 8 into a digital signal, and inputs it into the computer through a data line, and the computer analyzes the digital signal and The signal of the tiny vibration force can be obtained through operation, and the power amplifier amplifies the output signal of the computer and outputs it to the piezoelectric actuator 5 .

Figure 4 shows the simulation diagram of the system control. A 10kg load is installed on the load plate and a simple harmonic disturbance force is applied in the vertical direction. The frequency of the disturbance force is the same as the first-order frequency of the system. It can be seen from the response of the first-order modal displacement before and after control that the system can obviously suppress the system resonance after the control is applied, and the control effect is obvious.

Although the illustrative specific embodiments of the present invention have been described above, so that those skilled in the art can understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, As long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

Claims (7)

1. a small-sized microvibration measuring and control system is characterized in that comprising: base (6), loading disk (3), four folded beams (4), data PIAPACS (10); Described folded beam (4) includes two crossbeams (9), and the upper and lower surface of each crossbeam (9) is pasted one deck piezoelectric patches, and outer piezoelectric patches is as piezoelectric actuator (5), and the internal layer piezoelectric patches is as piezoelectric sensor (8); Described folded beam (4) is positioned between loading disk (3) and the base (6), compresses by bolt (2) to connect; Four folded beams (4) are uniformly distributed along the circumference at loading disk (3) lower surface, and load connects firmly by the through hole (1) on the loading disk (3) and loading disk (3), and base (6) connects with stiff end by through hole (7); When the sensor, eight piezoelectric sensors (8) are measured the voltage signal of three dynamic force of load and three dynamic bending moment directions and it are transferred to data and process and control system (10) the treated information that obtains six disturbing forces; During as controller, the signal that each piezoelectric sensor records is after data PIAPACS (10) is processed, based on the disturbing force information that records, data PIAPACS (10) will send voltage signal is used as power its generation to corresponding piezoelectric actuator (5), thereby realizes the inhibition to the load vibration.

2. small-sized microvibration measuring according to claim 1 and control system, it is characterized in that: described eight piezoelectric sensors (8), eight piezoelectric actuators (5) are d ₃₁The type piezo ceramic element.

3. small-sized microvibration measuring according to claim 1 and control system is characterized in that: described loading disk (3) be shaped as circle, eight counter sinks are arranged in order to connect piezoelectricity folded beam (4) on it, four bolt holes (1) are in order to connect load.

4. small-sized microvibration measuring according to claim 1 and control system, it is characterized in that: described eight piezoelectric sensors (8) are symmetrically distributed on piezoelectricity folded beam (4) inside surface.

5. small-sized microvibration measuring according to claim 1 and control system, it is characterized in that: described eight piezoelectric actuators (5) are symmetrically distributed on piezoelectricity folded beam (4) outside surface.

6. small-sized microvibration measuring according to claim 1 and control system, it is characterized in that: described base (6) is square frame, four arc notch are arranged on the inside edge, have eight countersunk head through holes to be used for connecting piezoelectricity folded beam (4) on the framework, four bolt holes (7) are used for being connected and fixed end.

7. small-sized microvibration measuring according to claim 1 and control system, it is characterized in that: the two pairs of piezoelectric sensors (8) in described each piezoelectricity folded beam (4) and piezoelectric actuator (5) contraposition juxtaposition, can shorten system response time, improve control performance.

Images