CN101819084A - Self-adaptive harmonic suppression method of electro-hydraulic-type vibration simulation platform - Google Patents

Abstract

The invention aims to provide a self-adaptive harmonic suppression method of an electro-hydraulic-type vibration simulation platform. The method comprises the following steps of: generating an acceleration signal by an acceleration excitation signal; measuring an acceleration response signal of an electro-hydraulic-type vibration simulation platform by an acceleration sensor; constructing the difference of the acceleration response signal and the acceleration excitation signal to acquire a control error signal; generating a sinusoidal harmonic signal with the amplitude of 1 by a harmonic signal generator; adjusting two weights w1 and w2 according to the control error signal by a least square method; weighting the sinusoidal harmonic signal generated by the harmonic signal generator and a signal obtained after shifting the phase of the sinusoidal harmonic signal at 90 degrees; and summing the weighted signals, adding the acceleration excitation signal and acting on the electro-hydraulic-type vibration simulation platform. The invention has little calculation amount, good real-time performance and self-adaptive operation in the whole process, and can effectively suppress harmonics in the electro-hydraulic-type vibration simulation platform and reduce the waveform distortion degree of the acceleration response signal of the electro-hydraulic-type vibration simulation platform.

Description

The electro-hydraulic-type vibration simulation platform self-adaptive harmonic suppression method

Technical field

What the present invention relates to is a kind of inhibition method of ripple, specifically can reduce the inhibition method of the ripple of waveform distortion.

Background technology

Hydraulic system has power-weight ratio and the mechanical mass ratio is big, and response is quick, and band system band is wide, and rigidity is big, and antijamming capability is strong, and error is little, the precision advantages of higher.Therefore in big displacement, use electro-hydraulic-type vibration simulation platform many under the situation of big exciting force.Electro-hydraulic-type vibration simulation platform adopts the Acceleration Control mode, by the motion of electrohydraulic servo valve control hydraulic cylinder, produces oscillating movement, and then simulates the vibrating effect that needs.

Sine vibration test is a kind of typical dynamic characteristic test method, and various periodic vibrations can be studied by the form of sinusoidal vibration.Electro-hydraulic-type vibration simulation platform is when carrying out the sinusoidal excitation vibration, and output acceleration waveform has tended to higher hamonic wave, causes the serious distortion of waveform.The basic reason that produces waveform distortion is the non-linear factor that exists in the system, and these non-linear factors are mainly the servo-valve dead band, connect the hinge gap, connect the friction force of hinge friction force, actuator etc.And system exists such as non-linear factors such as dead band, gap, friction force inevitably owing to reasons such as machining, processing technology, machinery installations.For improving the vibrating effect of electro-hydraulic-type vibration simulation platform, reduce the waveform distortion of its acceleration responsive signal, often need the harmonic wave in the acceleration responsive signal is suppressed.

Article Adaptive feed-forward compensator for harmonic cancellation inelectro-hydraulic servo system. utilizes bandpass filter to obtain the harmonic signal that desire will suppress in the electrohydraulic servo system, and adjusts weights by the LMS algorithm; The shortcoming of these method maximums is bandpass filter, because obtain the harmonic signal that desire will suppress through bandpass filter, will change the phase place of harmonic signal inevitably, and that phase place plays a part in harmonic wave suppresses is very crucial.Article Simon Haykin.Adaptive FilterTheory has proposed the harmonic suppressing method based on the adaptive feedforward compensator on the basis of sef-adapting filter, its rudimentary algorithm is the LMS algorithm, but this method can cause changing in the phase place of trap place system, the closed loop characteristic of change system is in trap is present in the bandwidth of system or will cause the stability margin of system to reduce when neighbouring.In the LMS algorithm, when input vector is big, can run into the problem that gradient noise amplifies; The step parameter of LMS algorithm has determined convergence and stability, and the selection of step parameter speed of convergence and final imbalance compromise often; When the eigenvalue distribution of LMS algorithm input vector autocorrelation matrix is disperseed, LMS Algorithm Convergence variation, speed of convergence will be very slow, and initial value chosen the comparison sensitivity.

Summary of the invention

The object of the present invention is to provide the electro-hydraulic-type vibration simulation platform self-adaptive harmonic suppression method that reduces acceleration waveform degree of distortion, improves the vibration test effect.

The object of the present invention is achieved like this:

Electro-hydraulic-type vibration simulation platform self-adaptive harmonic suppression method of the present invention is that the acceleration pumping signal produces acceleration signal, acceleration transducer records the acceleration responsive signal of electro-hydraulic-type vibration simulation platform, degree of will speed up response signal and acceleration pumping signal are made the controlled error signal of difference, the harmonic signal generator produces the multifrequency sinusoid signal, the multifrequency sinusoid signal amplitude is 1, by least-squares algorithm, according to two weight w of departure signal adjustment ₁And w ₂, and be weighting in the signal that obtains behind multifrequency sinusoid signal that the harmonic signal generator produces and phase shift 90 degree thereof, the signal after the weighting is done and, with the addition of acceleration pumping signal after the signal that obtains act on electro-hydraulic-type vibration simulation platform.

Electro-hydraulic-type vibration simulation platform self-adaptive harmonic suppression method of the present invention can also comprise:

Described least-squares algorithm is

$\left\{\begin{array}{c}W\left(k\right)=W(k-1)+K\left(k\right)e\left(k\right)\\ K\left(k\right)=P(k-1)X\left(k\right){[X^T\left(k\right)P(k-1)X\left(k\right)+1]}^{-1}\\ P\left(k\right)=[I-K\left(k\right)X^T\left(k\right)]P(k-1)\end{array}\right.$

In the formula, e (k) is the departure signal, and W (k) is a weight vector, and X (k) is an input vector, and K (k) is a gain matrix, and P (k) is a symmetric matrix, and I is a unit matrix.

Advantage of the present invention is: calculated amount is little, real-time performance good, and whole process adaptive carries out, and can effectively suppress the harmonic wave in the electro-hydraulic-type vibration simulation platform, reduces the waveform distortion of electro-hydraulic-type vibration simulation platform acceleration responsive signal.

Description of drawings

Fig. 1 has the electro-hydraulic-type vibration simulation platform control principle figure that harmonic wave suppresses;

The structural drawing that Fig. 2 suppresses for harmonic wave;

The structural drawing that Fig. 3 suppresses simultaneously for multiple harmonic.

Embodiment

For example the present invention is done description in more detail below in conjunction with accompanying drawing:

In conjunction with Fig. 1～3, the acceleration pumping signal produces the acceleration input signal of electro-hydraulic-type vibration simulation platform among Fig. 1, and acceleration transducer records the acceleration feedback signal of electro-hydraulic-type vibration simulation platform, and poor with the acceleration input signal, controlled error signal; After the departure signal suppresses the effect of module through harmonic wave, its output do with the acceleration input signal and, and act on electro-hydraulic-type vibration simulation platform.

In conjunction with Fig. 2, the harmonic wave among Fig. 1 suppresses module by harmonic signal generator, phase-shifter, weight w as can be known ₁And w ₂, composition such as least-squares algorithm.Least-squares algorithm is

$\left\{\begin{array}{c}W\left(k\right)=W(k-1)+K\left(k\right)e\left(k\right)\\ K\left(k\right)=P(k-1)X\left(k\right){[X^T\left(k\right)P(k-1)X\left(k\right)+1]}^{-1}\\ P\left(k\right)=[I-K\left(k\right)X^T\left(k\right)]P(k-1)\end{array}\right.$

In the formula, e (k) is the departure signal, and W (k) is a weight vector, and X (k) is an input vector, and K (k) is a gain matrix, and P (k) is a symmetric matrix, and K (k) and P (k) become when being, I is a unit matrix.

Least-squares algorithm is a convergent on the average meaning, and the weight vector estimated value is no inclined to one side; The convergence of least-squares algorithm on equal square meanings is independent of the eigenwert of the correlation matrix of input vector, and its rate of convergence is than the fast order of magnitude of LMS algorithm.

For sine vibration test, one of index that waveform distortion requires often.THD (TotalHarmonic Distortion, rate of total harmonics) is defined as

$\mathrm{THD}=\frac{\sqrt{A_2^2+A_3^2+A_4^2+\·\·\·}}{A_1}\×100\%$

In the formula, A ₄Be the fundamental frequency response amplitude; A ₂, A ₃..., be the amplitude of each harmonic.

Acceleration responsive signal to electro-hydraulic-type vibration simulation platform is done spectrum analysis, can obtain harmonic frequency and distribution situation thereof in the acceleration responsive signal.The harmonic signal generator produces signal x _s, its frequency is the acceleration responsive signal harmonic frequency that desire will suppress, and amplitude is 1, and this signal obtains signal x after spending through phase-shifter phase shift 90 _c, and then obtain input vector X (k)=[x _s(k), x _c(k)] ^T, then Dui Ying weight vector is W (k)=[w ₁(k), w ₂(k)] ^TLeast-squares algorithm is adjusted weight vector according to departure signal adaptive real-time online, and weight vector obtains harmonic wave amount of suppression X after to the input vector weighted sum ^T(k) W (k) acts on electro-hydraulic-type vibration simulation platform after it and the addition of acceleration pumping signal, thereby reduces the waveform distortion of electro-hydraulic-type vibration simulation platform acceleration responsive signal, improves the control performance of electro-hydraulic-type vibration simulation platform.

As seen the critical process in electro-hydraulic-type vibration simulation platform self-adaptation harmonic wave suppresses has:

(1) the acceleration responsive signal that records of acceleration pumping signal and acceleration transducer is poor, controlled error signal.

(2) the harmonic signal generator produces the multifrequency sinusoid signal, and its frequency is the acceleration responsive signal harmonic frequency that desire will suppress, and amplitude is 1.

(3) least-squares algorithm is adjusted weight vector according to departure signal adaptive real-time online, after the input vector weighted sum, obtains the harmonic wave amount of suppression, and with the addition of acceleration pumping signal after act on electro-hydraulic-type vibration simulation platform.

In conjunction with Fig. 3, when subharmonic suppressed simultaneously, the harmonic signal generator produced n multifrequency sinusoid signal, x to n (n is a positive integer, and n 〉=2) _S1, x _S2..., x _Sn, their frequency is the desire harmonic frequency that will suppress respectively, obtains their phase shift component, x through the phase shift effect _C1, x _C2..., x _Cn, form input vector

X(k)＝[x _s1(k)，x _c1(k)，x _s2(k)，x _c2(k)，…，x _sn(k)，x _cn(k)] ^T

Corresponding weight vector is

W(k)＝[w ₁(k)，w ₂(k)，…，w _n(k)] ^T

Least-squares algorithm is adjusted weight vector according to departure signal adaptive real-time online, and weight vector obtains harmonic wave amount of suppression X after to the input vector weighted sum ^T(k) W (k) acts on electro-hydraulic-type vibration simulation platform after it and the addition of acceleration pumping signal, reaches the effect that suppresses multiple harmonic simultaneously.

Claims (2)

1. electro-hydraulic-type vibration simulation platform self-adaptive harmonic suppression method, it is characterized in that: the acceleration pumping signal produces acceleration signal, acceleration transducer records the acceleration responsive signal of electro-hydraulic-type vibration simulation platform, degree of will speed up response signal and acceleration pumping signal are made the controlled error signal of difference, the harmonic signal generator produces the multifrequency sinusoid signal, the multifrequency sinusoid signal amplitude is 1, by least-squares algorithm, according to two weight w of departure signal adjustment ₁And w ₂, and be weighting in the signal that obtains behind multifrequency sinusoid signal that the harmonic signal generator produces and phase shift 90 degree thereof, the signal after the weighting is done and, with the addition of acceleration pumping signal after the signal that obtains act on electro-hydraulic-type vibration simulation platform.

2. electro-hydraulic-type vibration simulation platform self-adaptive harmonic suppression method according to claim 1 is characterized in that: described least-squares algorithm is

$\left\{\begin{array}{c}W\left(k\right)=W(k-1)+K\left(k\right)e\left(k\right)\\ K\left(k\right)=P(k-1)X\left(k\right){[X^T\left(k\right)P(k-1)X\left(k\right)+1]}^{-1}\\ P\left(k\right)=[I-K\left(k\right)X^T\left(k\right)]P(k-1)\end{array}\right.$

In the formula, e (k) is the departure signal, and W (k) is a weight vector, and X (k) is an input vector, and K (k) is a gain matrix, and P (k) is a symmetric matrix, and I is a unit matrix.

Images