CN103792936A - Feature analysis method for linear servo system based on saturation drive signals - Google Patents

Abstract

The invention provides a feature analysis method for a linear servo system. According to the electrical and mechanical features of the linear servo system, saturation drive signals, amplitude values and duration time are selected; under the amplitude values and the duration time, a saturation drive experiment is carried out on the linear servo system, and actual displacement data in the motion direction of the linear servo system are recorded; the actual displacement data are analyzed through a difference method, and the speed data and the acceleration data of the linear servo system in the motion direction of the linear servo system under the extreme motion condition are obtained; the acceleration data are analyzed through Morlet wavelet transformation, and the frequency data of the linear servo system under the extreme motion condition are obtained; direct data reference bases are provided for the design and development of a motion controller and the study of a motion planning and control method. The feature analysis method for the linear servo system is easy and convenient to implement, small in algorithm operand, easy to achieve in the field and flexible in debugging process.

Description

Linear servo system characteristic analysis method based on saturation activation signal

Technical field

What the present invention relates to is the system features analytical approach in movement control technology field, specifically a kind of linear servo system characteristic analysis method based on saturation activation signal.

Background technology

Compare traditional electric rotating machine, the revolutionary feature of linear electric motors is directly to convert electrical energy into straight-line mechanical energy, has saved the intermediate link rotatablely moving to rectilinear motion conversion.Linear electric motors rely on the features such as its high thrust-weight ratio, high rigidity, high acceleration and high precision, become the high main flow core component that accelerates high-speed, high precision kinematic system equipment, be widely used in fields such as high-end numerically-controlled machine, IC encapsulation and manufacture and microelectronics.Along with improving constantly of production efficiency and the quality of production, the requirement of the acceleration of associated production equipment, speed and positioning precision is more and more higher.This has brought stern challenge to motion control developer, and the motion controller that it need to be designed and developed can rationally utilize under the prerequisite of linear servo system feature, realizes the high production requirement of accelerating high-speed, high precision kinematic system equipment.

Linear servo system is a complication system that integrates the multiple kinds of energy forms such as mechanical, electrical, magnetic and heat energy.Linear electric motors are as the chief component of system, and its performance is not only relevant to the characteristic such as mechanical, electrical, magnetic of itself, and closely bound up with mechanical system.Therefore traditional for motor or mechanical system separately research be difficult to realize entire system signature analysis.At control field, the linear servo system feature that researchist is concerned about refers to velocity information, acceleration information and the frequency information etc. in its system limits motion process.In motion controller performance history, velocity information, acceleration information and the frequency information of how to confirm linear servo system in extreme sport process becomes primarily dealing with problems of the personnel of designing and developing.

In control field, often adopt linearity or logarithm frequency sweeping method to measure the natural frequency of servo-drive system, in order to characterize the frequency information of servo-drive system in motion process.But these methods, in obtaining frequency information, are difficult to obtain more system features, as velocity information and acceleration information.In order to obtain velocity information and the acceleration information of servo-drive system, tester needs more method and experiment to measure.In addition, the natural frequency of obtaining by these class methods, can not directly represent the frequency information of servo-drive system in motion process.

Find through retrieval, Kim etc. are at document " Design and performance tuning of sliding-mode controller for high-speed and high-accuracy positioning systems in disturbance observer framework " (IEEE Transactions on Industrial Electronics, 2009, 56 (10): 3798-3809.) natural frequency of obtaining controlled device in by calculating the mode of dynamic model parameter characterizes the frequency information in motion process, but this method needs dynamic model parameter accurately, operability is in actual applications not strong.

In sum, available technology adopting natural frequency characterizes the frequency information in motion process, is difficult to accurately characterize the frequency information in motion process; In addition when obtaining frequency information, be difficult to obtain other system features, as velocity information and acceleration information, thereby affect motion Controller Design and exploitation.

Summary of the invention

For prior art above shortcomings, the invention provides a kind of linear servo system characteristic analysis method based on saturation activation signal.The method can not only effectively be obtained velocity information and the acceleration information of linear servo system under extreme sport situation, and can the frequency information of accurate analysis linear servo system under identical limit moving condition, for motion Controller Design and exploitation, and motion planning and control method research provide direct data reference frame.

The invention provides a kind of linear servo system characteristic analysis method, comprising:

(1), according to the electric and mechanical features of linear servo system, select saturation activation signal, amplitude and duration;

(2), under amplitude and duration, carry out the saturation activation experiment of linear servo system, and record the actual displacement data in linear servo system direction of motion;

(3) analyze actual displacement data by difference method, obtain the linear servo system velocity information in linear servo system direction of motion and acceleration information under extreme sport situation;

(4), by the acceleration information obtaining in Morlet wavelet transformation analysis step (3), obtain the frequency information of linear servo system under extreme sport situation;

Extreme sport situation is the moving situation of linear servo system while adding saturation activation signal.

Further, in step (1), saturated pumping signal is saturation voltage pumping signal or saturation current pumping signal.

Further, linear servo system comprises motion controller, driver element, topworks and auxiliary equipment.

Further, in step (2), carry out the saturation activation experiment of linear servo system, comprise the following steps:

(21) send saturation activation signal by motion controller, drive linear servo system motion;

(22) record contactless grating chi feedback signal, contactless grating chi feedback signal is corresponding actual displacement data.

Further, in step (22), saturated pumping signal is saturation voltage pumping signal, and the amplitude of saturation voltage pumping signal is ± 10V that the duration of positive and negative saturation voltage is 5ms.

Further, while recording contactless grating chi feedback signal in step (22), select effectively to preserve length.By selecting effectively to preserve length, under the certain condition of memory capacity, can determine the quantity of preserving displacement data.

Further, effectively preserving length is 200.

Further, step (4) comprises step:

(41) continuous wavelet transform is the inner product of signal and wavelet function:

$\mathrm{Wf}(u,s)=\frac{1}{\sqrt{s}}{\∫}_{-\∞}^{+\∞}f\left(t\right)\mathrm{\ψ}\left(\frac{t-u}{s}\right)\mathrm{dt}$

Wherein,

for signal, Wf (u, s) is wavelet function ψ _u,scorresponding wavelet coefficient, describes near signal vibration with the yardstick s u of position;

(42) analysis frequency lower limit and upper frequency limit are set, and select frequency to count, obtain corresponding time-frequency distributions;

(43), in the time-frequency distributions obtaining, obtain the first frequency being evoked from step (42).

The formula of the Morlet wavelet transformation adopting in step (41) further, is:

$\mathrm{\&psi;}\left(t\right)={\mathrm{\&pi;}}^{-1/4}(e^{-{\mathrm{j\&omega;}}_{0}t}-e^{-{\mathrm{\&omega;}}_0^2/2})e^{{-\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000456123160000021.png,HDA0000456123160000032.png"\; state="\{\{state\}\}">t</figure-callout>}}^2/2}.$

Further, under step (42) medium frequency, be limited to 100Hz, upper frequency limit is 5000Hz, and it is 256 that frequency is counted.

Compared with prior art, linear servo system characteristic analysis method provided by the invention has following beneficial effect:

(1) adopt based on saturation activation signal, carry out the saturation activation experiment of linear servo system, Obtaining Accurate the displacement information of linear servo system;

(2) adopt difference method to analyze actual displacement data, obtain velocity information and the acceleration information of linear servo system;

(3) adopt Morlet wavelet transformation, have good Time-Frequency Localization characteristic, the time-frequency characteristic of energy reflected well analyzed signal, effectively analyzes the frequency information of linear servo system under extreme sport condition;

(4) test easyly, algorithm operation quantity is little, is easy to on-the-spot realization, and debug process is flexible.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of the linear servo system characteristic analysis method in one embodiment of the present of invention;

Fig. 2 is saturation voltage pumping signal figure;

Fig. 3 is the actual displacement figure of the linear servo system Y-axis in one embodiment of the present of invention;

Fig. 4 is the velocity information figure of the linear servo system Y-axis in one embodiment of the present of invention;

Fig. 5 is the acceleration information figure of the linear servo system Y-axis in one embodiment of the present of invention;

Fig. 6 is the frequency information figure of the linear servo system Y-axis in one embodiment of the present of invention.

Embodiment

Elaborate for embodiments of the invention below, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

In the present embodiment, adopt permanent magnet linear synchronous motor (Permanent Magnet Linear Synchronous Motor, PMLSM) Y-axis of direct driving machine electric system is as research object, by the linear servo system of the compositions such as Embedded Motion, driver element, topworks and other auxiliary equipment is carried out to saturation activation experiment, and then analyze velocity information and the acceleration information of Y-axis under extreme sport situation, and under extreme sport situation the natural frequency of permanent magnet linear synchronous motor

As shown in Figure 1, the linear servo system characteristic analysis method that the present embodiment provides comprises the following steps:

Step 1, according to the electric and mechanical features of permanent magnet linear synchronous motor Y-axis, select saturation voltage signal as experiment saturation activation signal used, saturation voltage pumping signal as shown in Figure 2, its amplitude is ± 10V, the duration of positive and negative saturation voltage is 5ms, and the sampling period of linear servo system is set to 0.1ms;

Also can select saturation current pumping signal as experiment saturation activation signal used;

Step 2, the experiment parameter of saturation voltage pumping signal is set, sends by Embedded Motion Control System the voltage saturation pumping signal that duration is 10ms, drive the Y-axis motion of permanent magnet linear synchronous motor, record corresponding contactless grating chi feedback signal, i.e. corresponding actual displacement information;

In order to store more displacement information, select 200 as effectively preserving length, actual displacement is as shown in Figure 3.

Step 3, choose length and be 200 actual displacement data and carry out difference, the actual speed information of permanent magnet linear synchronous motor Y-axis can obtain saturation voltage exciter response time, as shown in Figure 4, as can be seen from Figure 4, permanent magnet linear synchronous motor Y-axis has the ability that maximal rate is 0.689m/s that reaches.By the actual speed information difference again of permanent magnet linear synchronous motor Y-axis, obtain its acceleration information, as shown in Figure 5, by analyzing its acceleration information, the peak acceleration that obtains this permanent magnet linear synchronous motor Y-axis is 220m/s ²with average acceleration be 145m/s ².In addition, also can obtain the acceleration of this permanent magnet linear synchronous motor Y-axis, acceleration from 0 time that accelerates to average acceleration be 0.5ms, that is to say, Y-axis has the ability that reaches average acceleration at 5 servo periods.

And then the information that the design of the motion planning of Y-axis can be obtained according to this step, carries out rational motion planning, makes Y-axis reasonably bring into play the performance of oneself.

Step 4, by the corresponding actual acceleration data of Morlet wavelet transformation analysis, obtains the frequency information of permanent magnet linear synchronous motor Y-axis under extreme sport situation, and concrete steps are as follows:

A) for a given signal

continuous wavelet transform is the inner product of signal and wavelet function:

$\mathrm{Wf}(u,s)=\frac{1}{\sqrt{s}}{\&Integral;}_{-\&infin;}^{+\&infin;}f\left(t\right)\mathrm{\&psi;}\left(\frac{t-u}{s}\right)\mathrm{dt},$

Wherein Wf (u, s) is called small echo ψ _u,scorresponding wavelet coefficient, description signal is with the vibration of yardstick s near the u of position, and the formula of the Morlet wavelet transformation adopting in the present embodiment is as follows:

$\mathrm{\&psi;}\left(t\right)={\mathrm{\&pi;}}^{-1/4}(e^{-{\mathrm{j\&omega;}}_{0}t}-e^{-{\mathrm{\&omega;}}_0^2/2})e^{{-\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000456123160000021.png,HDA0000456123160000032.png"\; state="\{\{state\}\}">t</figure-callout>}}^2/2}.$

B) arrange and under analysis frequency, be limited to 100Hz and upper frequency limit is 5000Hz, selecting frequency to count is 256, obtains corresponding time-frequency distributions, as shown in Figure 6.

C) as can be known from Fig. 6: permanent magnet linear synchronous motor Y-axis is under extreme sport situation, and first frequency being evoked is greatly about 290Hz left and right.

And then the cutoff frequency of the low-pass filter that the size that the control method of Y-axis can be evoked frequency according to first relates to control method carries out choose reasonable.In addition, also can carry out with reference to this frequency the calculating of controller parameter, as the parameter of the PID controller based on POLE PLACEMENT USING.

Linear servo system characteristic analysis method provided by the invention can be used for the linear electric motors of other type, and the present invention is not restricted this.

The part that do not elaborate in above-mentioned explanation is disclosed knowledge and technology in this professional domain.

Linear servo system characteristic analysis method provided by the invention, adopts based on saturation activation signal, carries out the saturation activation experiment of linear servo system, Obtaining Accurate the displacement information of linear servo system; Adopt difference method to analyze actual displacement data, obtain velocity information and the acceleration information of linear servo system; Adopt Morlet wavelet transformation, have good Time-Frequency Localization characteristic, the time-frequency characteristic of energy reflected well analyzed signal, effectively analyzes the frequency information of linear servo system under extreme sport condition; For motion Controller Design and exploitation, and motion planning and control method research provides direct data reference frame, tests easyly, and algorithm operation quantity is little, is easy to on-the-spot realization, and debug process is flexible.

More than describe preferred embodiment of the present invention in detail.Should be appreciated that those of ordinary skill in the art just can design according to the present invention make many modifications and variations without creative work.Therefore, all technician in the art, all should be in by the determined protection domain of claims under this invention's idea on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment.

Claims (10)

1. a linear servo system characteristic analysis method, is characterized in that, described method comprises:

(1), according to the electric and mechanical features of linear servo system, select saturation activation signal, amplitude and duration;

(2), in described amplitude with under the described duration, carry out the saturation activation experiment of described linear servo system, and record the actual displacement data in described linear servo system direction of motion;

(3) analyze described actual displacement data by difference method, obtain velocity information and acceleration information in the described linear servo system direction of motion of described linear servo system under extreme sport situation;

(4), by the described acceleration information obtaining in Morlet wavelet transformation analysis step (3), obtain the frequency information of described linear servo system under extreme sport situation;

Described extreme sport situation is the moving situation of described linear servo system while adding the above saturation activation signal.

2. linear servo system characteristic analysis method as claimed in claim 1, is characterized in that, saturation activation signal described in step (1) is saturation voltage pumping signal or saturation current pumping signal.

3. linear servo system characteristic analysis method as claimed in claim 2, is characterized in that, described linear servo system comprises motion controller, driver element, topworks and auxiliary equipment.

4. linear servo system characteristic analysis method as claimed in claim 3, is characterized in that, carries out the saturation activation experiment of described linear servo system in step (2), comprises the following steps:

(21) send described saturation activation signal by described motion controller, drive described linear servo system motion;

(22) record contactless grating chi feedback signal, described contactless grating chi feedback signal is corresponding actual displacement data.

5. linear servo system characteristic analysis method as claimed in claim 4, it is characterized in that, described in step (22), saturation activation signal is saturation voltage pumping signal, and the amplitude of described saturation voltage pumping signal is ± 10V that the duration of positive and negative saturation voltage is 5ms.

6. linear servo system characteristic analysis method as claimed in claim 4, is characterized in that, while recording described contactless grating chi feedback signal, selects effectively to preserve length in step (22).

7. linear servo system characteristic analysis method as claimed in claim 5, is characterized in that, described effective preservation length is 200.

8. linear servo system characteristic analysis method as claimed in claim 1, is characterized in that, step (4) comprises step:

(41) continuous wavelet transform is the inner product of signal and wavelet function:

$\mathrm{Wf}(u,s)=\frac{1}{\sqrt{s}}{\&Integral;}_{-\&infin;}^{+\&infin;}f\left(t\right)\mathrm{\&psi;}\left(\frac{t-u}{s}\right)\mathrm{dt}$

Wherein,

for described signal, Wf (u, s) is wavelet function ψ _u,scorresponding wavelet coefficient, describes near the vibration with the yardstick s u of position of described signal;

(42) analysis frequency lower limit and upper frequency limit are set, and select frequency to count, obtain corresponding time-frequency distributions;

(43), in the described time-frequency distributions obtaining, obtain the first frequency being evoked from step (42).

9. linear servo system characteristic analysis method as claimed in claim 8, is characterized in that, the formula of the Morlet wavelet transformation adopting in step (41) is:

$\mathrm{\&psi;}\left(t\right)={\mathrm{\&pi;}}^{-1/4}(e^{-{\mathrm{j\&omega;}}_{0}t}-e^{-{\mathrm{\&omega;}}_0^2/2})e^{{-t}^2/2}.$

10. linear servo system characteristic analysis method as claimed in claim 8, is characterized in that, described in step (42), lower-frequency limit is 100Hz, and described upper frequency limit is 5000Hz, and it is 256 that described frequency is counted.

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