SU986509A1 - Electrodynamic vibrator - Google Patents

Description

(54) ELECTRODYNAMIC VIBRATOR

The invention relates to vibration technology and can be used in stands for vibration testing of various objects.

An electrodynamic vibrator is known, comprising an electrodynamic exciter and a control system, in which a satisfactory accuracy of moving an object from a column of an exciter according to a signal from a master oscillator CII is provided.

However, even this vibrator lacks the ability to stabilize or control with a force action according to a given program.

The closest to the technical essence of the invention is an electric JpIhmic vibrator containing a magnetic circuit with a bias winding connected to a DC power source mounted in an air gap of the PODVIZhYY5YY coil of the magnetic circuit connected to the output a power amplifier, a differentiation unit connected to a moving coil displacement sensor and a summing amplifier, to which are also connected in parallel connected me I am waiting for the generator and the C23 control unit, c However, in the vibrator, the accuracy of obtaining the Dissolved force on the object and especially the specified waveform in the presence of JQ signal and parametric perturbations is not satisfactory. These disturbances should include the nonlinearity and non-stationarity of electrokechanical and other characteristics and parameters of the vibrator and the test object, and

15 also external force effects on the vibrator and the object. This disadvantage is explained by the fact that in the known device linearization correction blocks are used, which perform their function of providing the specified forms of force action on the object and oscillations only in a small range of disturbance variation.

The aim of the invention is to improve the reproduction accuracy of a given force effect on the test object in the presence of signal and parametric disturbances.

Delivered, if achieved by

30 that the electrodynamic vibrator is provided with a series-connected comparison unit and a two-position relay in parallel with which an integrating amplifier is connected, the inputs of the comparison unit are connected to the outputs of the differentiation unit and the summing amplifier, and the outputs of the integrating amplifier and the two-position relay are connected to the summing inputs of the power amplifier. Figure 1 shows a functional diagram of an electrodynamic vibrator; Fig. 2 shows an oscillogram of the moving coil movement. The electrodynamic vibrator contains a magnetic circuit 1 s, a bias winding 2 connected to a DC source 3, a moving coil 4 having, for example, a cylindrical winding 5 connected in series with a control unit b, driving oscillator 7, 20 summing amplifier 8, comparison unit 9, an on-off relay 10 and a power amplifier 11 connected to the moving coil 4. The vibrator also contains an integral amplifier 12, 25 connected in parallel to the relay 10, a moving sensor 13 of the moving coil 4 connected The second input of the summing amplifier 8 and the input of the differentiation unit 14, the outputs of which are connected to the inputs of the summing amplifier 8 and the comparison unit 9. The control unit performs the function of setting the amplitude, frequency, waveform and the test object. The device works as follows. The vibrational dynamics equations are written as ILO + JR-U. tx - "- P1x.xD or. (nix + FU, xt) 45 tf (x, x, x, t) + B (t) U, f (.k, x, t} - ;; - F (x , x, t) -n;: ((X, X, t); BUl-TSff.

de X - output value

(movement of the moving coil 4); 55

and - control voltage at the output of block 11;

I. - current in the winding 5;

L, R - inductance and resistance of the winding 5, respectively;

F (x, X, t) - mechanical forces

affecting 5 of metsi with b us bles (p mo my si ur x xd ur mi min

 ).(four):

de L is the magnitude of the mismatch (error) at the output of the Comparison 9;

Claims (2)

± and - are the levels of restrictions on the output voltage of the relay 10; - the measured value of the acceleration of the moving coil at the output of the block 14; Kch - kaofficit transmission unit 11. moving coil 4; Р - electrodynamic pulling force; m is the mass of the movable part of the vibrator; b - design parameter (coefficient of electromagnetic rigidity); t - time the dependence of the functions V and B on t is accompanied by the presence of signal and paraic disturbances. The device is realized by adapting along the vector of speed by the ganisation of sliding modes. In accordance with this, the summing function 8 performs the function of setting the desired value of the derivative of the output value n - the order of the mathematical (1), (2) vibrator. In the case of joint oscillations, the desired motion (see Fig. 2) can be designed linear, of the form, - (x (t) -X)) - T Z ay. X (t) X UHX ° Sinu) t, Ws 2Jf, (3) x, f - amplitude and frequency of oscillations, respectively; 3of TO is the desired values of the damping coefficient and constant time, respectively; x ° (t) is a given oscillatory motion; x ° (t) is the slowly varying component of the oscillatory motion; x is the desired acceleration value (n-1) -th derivative of the output value; y is the measured value of the moving speed of the moving coil 4 (at the output of block 14). For the submission of motion to vibrator (3) at the output of block 11, the following control algorithm is used: If the conditions of the paths of the control system 4 to the surface L 0 ° are satisfied and the sliding mode exists on it, then the movement D (, x , x, x) 0, which satisfies the desired differential equation (3) and does not depend on the power perturbations of the nonlinearity and unsteady state of the characteristics and parameters of the electrodynamic vibrator (its electromechanical scheme). In addition, for the normal operation of the proposed device, it is necessary to additionally fulfill the following condition: 1 I IO-TO, I where / u, is a small parameter that determines 4 speed of the trimming unit 14. It is convenient to use differential simulation and differentiate the quality of the real daunting (block 14) filter with transfer function WplMPJ UP + b P + l) -. (5) This vibrator belongs to a class of systems with separable motions. By always a structural transformation, we can highlight the speed of the contour of maintaining the derivative, in which the manifestation of perceptions and properties of the object of embossment is localized. For an approximate analysis of the dynamics of the vibrator, you can use the methods / separation of movements and harmonic linearization. In this case, the equations of dynamics will be quickly written in the operator form as follows: L – p ви vN (L,) M p ((& p – in (; - i l l °) –h (,. X. Where D is the harmonic component of the error, L °, O are slowly changing the power supply and output voltage, respectively, / q is the harmonic linearization coefficient, and A is the amplitude of high-frequency self-oscillations in the cycle. (6), (7) according to the method of harmonic balance, taken at B const in the correctness of the desired value. Since these are self-oscillations d d / a yu. is selected from the conditions, lO /: i Tj, where Tj min is the minimum value of the electromagnetic constant vibrator, then the high-frequency pulsations at the output are negligible. The circuit works with large harmonic signals at / its input, therefore the device is less sensitive to psychoses that are less critical to unaccounted for small inertia. This also leads to an increase in the accuracy of the operation of an electrodynamic vibrator. When the integrating amplifier 12 is switched on in parallel with the relay 10, the equations for harmonic and slowly varying components will take the form: a (V4 (A.4) p) -6 (t). “P (Mr)) / kx Lj) P) - V pKp-Vt. where K-1 is the coefficient of leverage of the integrating amplifier 12. From equation (9) it follows that with and x const Thus, and 0, regardless of the form of the function /. This leads to the enhancement of the invariance property of the electrolyte of a dynamic vibrator to disturbances. The introduction of new units into the electrodynamic vibrator made it possible to exclude the suspension unit along; Vision coil 4, thereby simplifying the control system. The vibrator provides processing, with the given quality, of both the required vibration mode and amplitude, and the required law of change in the force effect on the object (at i. Const proportional to the slowly varying component) under the action of perturbing factors fF rov (x, x, x, t), where FX fj Thus, when introducing into the electrodynamic vibrator of the synchronization unit, the relay and the integrating amplifier with a wide range of connections, a high-speed control loop is created, which operates in a sliding mode, in which localized and parry and fast signal and parametric disturbances. This leads to an increase in the degree of reproduction of a force effect on the object under test and a given waveform in the presence of signal and parametric disturbances, and consequently, the quality of the tests performed. Formula izob | Eteni Electrodynamic vibrator containing a magnetic circuit with a bias winding connected to a DC power source, a moving coil installed in the air gap of the gateway, longer than the length of the air gap of the magnetic circuit connected to the output of the power amplifier, a differentiation unit connected to a moving sensor coils and a summing amplifier, to which a master oscillator and a control unit are also connected in series, which are Due to the fact that, in order to increase the reproduction accuracy of a given force effect on the object under test in the presence of signal and parametric disturbances, it is equipped with a series-connected comparison unit and a two-position relay, in parallel with which an integrating amplifier is turned on, and which inputs of the comparison unit are connected to the outputs of the differentiation and summing unit amplifier, and outputs. an integrating amplifier and a two-position relay are connected to the summing inputs of the power amplifier. Sources of information taken into account during the examination 1. USSR author's certificate 532402, cl. In About In 1/04, 1975. 2. USSR author's certificate number 623585, cl. B 06 B 1/04, 197 (prototype). .one