RU2734839C1 - Vibration process machine dynamic state control device - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to the field of machine building. Device for controlling the dynamic state of the vibrating process machine comprises a solid body on elastic supports, a vibration exciter, sensors, servo drives with leadscrews. Lead screws and servo drives are additionally installed on top of the working element along its entire length for displacement of vibration exciter located in the centre along it.

EFFECT: possibility of controlling the dynamic state of the vibration process machine by changing the position of the vibration exciter.

1 cl, 5 dwg

Description

The invention relates to the field of vibration technology and can be used in the design and improvement of vibration technological machines.

The dynamic state of the working bodies of technological machines is created by vibration exciters of various nature, which, as a rule, is the formation of a vibration force at some point of the working body. Such a force sets the system in motion and determines the corresponding form of distribution of the vibration amplitudes of the points of the working body along its length.

The conditions for excitation of vibrations of the working body are quite diverse, depend on many factors, which stimulates the search and development of new methods and means for assessing, monitoring and controlling the dynamic states of technological vibration machines [1-3].

Among the rational methods and means of exciting vibration fields, correcting dynamic states, variants with the installation of one vibration exciter have become widespread; Approaches focused on the introduction of additional links have gained some popularity, which is described in sufficient detail in the scientific literature [1-3].

At the same time, a number of directions in the search for rational solutions have not yet received the proper degree of detailing of ideas about the action of force factors, which is associated with non-traditional methods of moving the source of external excitation.

In the course of the patent search, a number of analogous inventions were identified.

1. Known invention [Violin D.O. "Vibration installation", 95574 U1, IPC В22С 15/00, priority 07/10/2010], which is a vibration installation to provide a special effect of vibrations - "imitation of an earthquake" by transferring torque from the shaft with a changed center of gravity of the working machine through the supports to the plate of

iron installed on the base of the frame-frame. The technical result from the use of this technical solution is achieved due to the fact that the vibration unit consists of a frame made in the form of a metal block-frame, in the form of a parallelepiped, sheathed with steel sheet rolled, a rubber gasket is placed on top of its edges (to mitigate vibration). Then a plate of iron is placed on the latter, under which a vibration exciter is pre-mounted in the form of a working machine with an electric motor with rigidly fixed supports, while the working machine has a shaft with a changed center of gravity, which is connected to the electric motor through a coupling. It should be noted that the shaft with a changed center of gravity is mounted on sleeve bearings (the latter are not shown in the drawing).

The disadvantages of this invention are the lack of regulation of the dynamic state, as well as the lack of a mathematical description of the operating modes of the device.

2. Known device for damping vibrations [Eliseev SV, Yermoshenko Y. V., Moscow AO, Bolshakov RS. "Device for damping vibrations", patent No. 2498126 C2, IPC F16F 7/112, F16F 15/027 priority 11/10/2013], containing elastic elements and a system of dynamic vibration damping in the form of an elastically attached mass. The object of protection contains an adjustable system of dynamic vibration damping. The dynamic damping system contains a pneumatic cylinder with a valve, a compressor with a pipeline and a control system with sensors. The air spring is secured to a base plate that moves in a dovetail joint with a self-braking screw device. The sensors are installed on the protected object and on the dynamic vibration damper and transmit information about the state of the protected object and the dynamic damper to the information processing unit for acceptance

decisions about turning on the compressor and the screw device. Achieved dynamic damping of vibrations in two coordinates.

The considered invention has a number of disadvantages, which include the complexity of the design and the inability to form stable dynamic modes of operation.

3. Known invention [Kavarma II, Kalnitsky AM, Kondratenko VF, Gorbachev YG [UA] "Vibration transporting machine", patent No. 2028264 C1, IPC B6527 / 20, priority 09.02.1995], which is a vibration drive containing a vibrator, in the housing of which an unbalanced shaft is mounted on bearings, connected by means of an elastic coupling to an electric motor. The body is fixed in the center of gravity of the working body of the vibrating machine, installed by means of elastic supports on a fixed frame, where the electric motor is also mounted. The clutch has a driving half-coupling, fixed on the motor shaft, and a driven half-coupling, fixed on the unbalanced shaft. The half-couplings are interconnected by elastic elements made, for example, in the form of petals from a conveyor belt. On the half of the coupling, an additional unbalance is fixed in phase with the unbalance shaft during the resonant tuning of the machine or in antiphase when it is tuned before the resonance.

The disadvantages of the presented analogue are the lack of regulation of the dynamic state and the lack of a mathematical description of the operating modes of the device.

4. For the prototype is taken a method of controlling the structure of the vibration field of a vibration technological machine based on the use of dynamic damping effects and a device for its implementation [Eliseev S.V., Eliseev A.V., Kaimov E.V., Nguyen D.Kh., Vyong K.Ch. "A method for controlling the structure of a vibration field of a vibration technological machine based on the use of dynamic damping effects and a device for its implementation", patent No. 2624757 C1, IPC F16F 15/02, priority

07/06/2017], consisting of a working body in the form of a solid body on elastic elements, having an inertial vibration exciter acting at a certain point, characterized by the introduction into the structural and technical scheme of the system of a device for converting motion in the form of a non-self-braking screw mechanism with a flywheel nut with movement along the working body of the point of application of the force arising during the operation of the elements of the screw pair, generating additional stabilizing movements of the working body so that the vibration field has a homogeneous structure and provides the possibility of regulating and tuning the vibration system to implement the necessary parameters of the technological process. A device that implements the method, which is a structural and technical unit consisting of a non-self-braking screw mechanism with a massive flywheel nut, on the end part of which a moment of forces can be created by pressing the brake shoe with a special drive, which generates a control action at a certain point of the working body of the vibration table; the device for converting motion is also characterized in that the point of application of the force on the working body can be changed as a result of moving the structural block along the working body using two synchronously operating electric drives that move the upper and lower parts of the structural and technical unit using lead screws controlled by a special software a block, which receives information from sensors that control the vibration state and the system for calculations according to the embedded mathematical model.

The main disadvantages of the prototype are the lack of a mode of joint operation of the extreme points of the vibration machine, as well as the presence in the system of an element that creates additional force.

The objective of the invention is to control the dynamic state of a vibratory technological machine by changing the position of the vibration exciter.

The device for controlling the dynamic state of a vibrating technological machine contains a solid body on elastic supports, a vibration exciter, sensors, servos with lead screws, characterized in that lead screws and servos are additionally installed on top of the working body along its entire length to move along it a vibration exciter located in the center.

The essence of the invention is illustrated by drawings.

FIG. 1 shows a schematic diagram of a vibratory technological machine with devices for adjusting the dynamic state, containing a support surface 1, a working body 2, a control unit 3, elastic elements 4, 5, sensors 6, 7, electric servos 8, 9, lead screws 10, 11, guides 12, vibration exciter 13, communication links 14, 15, 16, 17.

FIG. 2 shows a design diagram of the system of FIG. 1.

FIG. 3 shows a structural mathematical model (block diagram) of the original system of the technological vibration machine according to FIG. 2.

FIG. 4 shows a diagram of the location of the vibration node at

и

в стационарном режиме при

: а) случай

,

; б) случай

,

; в) случай

,

, узел колебаний - т. D,

; г) случай

,

, узел колебаний - т. D,

; д) случай

- узел колебаний бесконечно удален,

; е) случай

узел колебаний - т. D; ж) случай выноса узла колебаний т. А за пределы твердого тела; з) случай выноса узла колебаний за пределы т. В твердого тела.FIG. 5 shows the options for the relative position of the offsets along the coordinates

and

in stationary mode at

: a) case

,

; b) case

,

; c) case

,

, vibration node - point D,

; d) case

,

, vibration node - point D,

; e) case

- the vibration node is infinitely distant,

; f) case

vibration node - point D; g) the case of the removal of the vibration node m. A outside the rigid body; h) the case of the removal of the vibration node outside the limits of t. B of a rigid body.

The principle of operation of the device is implemented as follows.

The proposed invention implements a method for adjusting the dynamic state of a vibrating technological machine, which is carried out by a mechanical vibrating system consisting of a working body 2 (a solid body with mass M and moment of inertia J). The working body 2, through elastic elements 4 and 5 with corresponding stiffnesses k ₁ and k _2, rests on a fixed surface 1, and also has a vibration exciter 13 installed on top, driven by servo drives 8, 9 and lead screws 10, 11 along guides 12.

The operation of the system is controlled in automatic mode by the control unit 3, installed on a fixed supporting surface 1. The control unit is connected to sensors 6 and 7, which record the vibration amplitudes of the working body along the coordinates y1 and y2, through communication links 15, 17. Servos 8, 9 also have communication links 14, 16 with the control unit 3.

The control unit 3 contains a microprocessor that works out the algorithm for controlling the movement of the vibration exciter along the guides, which creates the possibility of changing the force factors along the coordinates y ₁ and y ₂ and makes it possible to obtain various dynamic modes of operation of the vibrating technological machine, including the formation of a ratio between the coordinates equal to one.

Theoretical substantiation of the device for controlling the dynamic state of a technological vibration machine

The practice of assessing, monitoring and managing the formation of dynamic states of technological vibration machines, the determination of dynamic reactions in the connections of system elements and strength calculations are focused on the possibility of representing technical objects in the form of mechanical vibration systems with several degrees of freedom (most often no more than three). It is assumed that technical objects perform small vibrations and have linear properties. Taking into account such approaches, the design diagram of the technological vibration machine shown in Fig. 1, can be represented in the form of a mechanical oscillatory system of a beam type with two degrees of freedom. The working body of the machine in this case is considered in the form of an extended rigid body (mass M and moment of inertia J) located on the support surface on elastic linear springs with stiffnesses k ₁ and k ₂ . Vibrations of an object are caused by an external harmonic force Q ₀ (Fig. 2), which is applied at point E, which is spaced from the center of mass (point O) of a rigid body at a distance l ₀ . The center of mass, in turn, is located at distances l ₁ and l ₂ from point. A and B of the working body. The movement of the system can be described in coordinate systems y ₁ , y ₂ or y ₀ , ϕ; between which there are relations

Where

It is assumed that the system performs small vibrations relative to the position of static equilibrium with the practical absence of forces of resistance to motion.

1. In accordance with [4], the force Q ₀ applied at point E can be transformed into a system of two forces applied at point E. A and B:

The system of differential equations of motion according to Fig. 1 can be represented in operator form based on the use of well-known approaches [2, 5]:

- комплексная переменная, значок

над переменной означает ее изображение по Лапласу при нулевых начальных условиях.Where

- complex variable, icon

over a variable means its Laplace image with zero initial conditions.

2. Using (4), (5), it is possible to introduce into consideration the structural mathematical model of the original system (Fig. 2) in the form of a structural diagram (Fig. 3) of a dynamically equivalent automatic control system [2].

The structural mathematical model has two partial blocks connected by inertial coupling.

и

определяются по координатам

и

выражениями3. Transfer functions of the system under the simultaneous action of two force factors

and

determined by coordinates

and

expressions

- является характеристическим частотным уравнением системы.Where

- is the characteristic frequency equation of the system.

From expressions (6), (7), the corresponding frequencies of dynamic vibration damping can be found:

-by coordinate

-

-by coordinate

-

In expressions (9), (10), it is assumed that

и

, когда выполняется условиеIn this case, α is, in essence, the coefficient of connectivity between external influences

and

when the condition

In [5], the features of the dynamic states of various technical objects are partially considered, within the framework of a scientific hypothesis about the possibility of practical implementation of the coefficient of connectivity of external forces in the form α. In this case, the connectivity of external influences in a constructive and technical form is realized due to the possible movement of point E of the working body. In accordance with (12), the connectivity coefficient α can take positive and negative values, and also take on extreme values when l ₀ changes.

4. From expressions (9), (10) it follows that the frequencies of dynamic damping of oscillations depend on the above introduced coefficient α. In conventional approaches, when the external influence is single and applied along

one of the coordinates, that is, either at point A or at point B, then the frequency of dynamic damping is determined by the so-called partial frequencies

или

, частоты динамического гашения колебаний совпадают с парциальными частотами, определяемыми (13), (14).In ordinary situations, when the system is acted upon by one force applied along the coordinate

or

, the frequencies of dynamic damping of oscillations coincide with the partial frequencies determined by (13), (14).

Let us introduce into consideration the transfer function of interpartial connections, the coefficient of connectivity of external forces α:

The physical meaning of the transfer function (15) lies in the fact that it gives an idea of the regularities of the distribution of the vibration amplitudes of the working body along its length. We transform (15) to the form

Expression (16) can be rewritten as

Where

и

, признав, чтоUsing expressions (15), (16), it is possible to detail the ideas about the connectivity coefficient of the vibration amplitudes along the coordinates

and

recognizing that

then from (16), (17) we obtain an expression for α

, на которой при заданных М, Jc², а, b и i выражение примет вид5. Knowing the parameters of the system M, Jc ² , a, b, i and setting the frequency ω ² , we can find the corresponding value of α. In turn, from (19) one can also find the frequency

, on which for given М, Jc ² , a, b and i the expression takes the form

From (19) it follows that for given α, i, M, Jc ² , a, b, k ₁ and k _2, one can find the frequency at which the required distribution of the vibration amplitudes of the points of the rigid body (or working body) is realized.

The parameter α, that is, the coefficient of connectivity of external influences is determined through the parameters a, b, α, which makes it possible to obtain

, то при известных l₁ и l₂ определяется и расположение точки приложения силы

. При настройке параметров вибрационного поля таким образом, что при известных параметрах системы, может быть реализован итеративный процесс получения необходимых настроечных данных для технологической машины. Обычно такие данные определяются при разработке технологического процесса.Insofar as

, then for known l ₁ and l ₂ , the location of the point of application of the force is determined

... When tuning the parameters of the vibration field in such a way that with the known parameters of the system, an iterative process of obtaining the necessary tuning data for the technological machine can be implemented. Typically, such data is determined during the development of the technological process.

приводится на диаграмме (фиг. 4).6. If the value of i is known, then, using the similarity conditions, it is possible to find the regularities of the distribution of the vibration amplitudes of the points of the working body along its length. If the value of α is known, then for given i, a, b, d, the position of the vibration node can be found. Variant of vibration amplitude distribution

is given in the diagram (Fig. 4).

From the similarity of triangles, we find that

then

Thus, the proposed approach allows creating conditions for determining the necessary data on the structure of the vibration field or the distribution of the vibration amplitudes of the points of the working body.

7. Expression (17) can be transformed to the form

From (19) with the parameters of the system determined by expressions (17 '), (17' '), it is possible to find the excitation frequency of the working body, which provides the required value of the parameter i.

8. Let us compare the variants of the formation of the distributions of the amplitudes of the points of the working body, assuming that the length AB (Fig. 1) is determined by the ratio

The general diagram of the relationship between the vibration amplitudes of the points of a rigid body can be represented by the diagrams shown in FIG. 5. Consideration of the diagrams in FIG. 5 gives an idea of

реализуется режим динамического гашения колебаний; по фиг. 5, б - режим колебаний по координате

. На фиг. 5, в и г, приведены режимы колебаний, когда узел колебаний (т. D) находится между тт. А и В, что предполагает возможности угловых колебаний совместно с поступательными движениями. При выполнении условия

узел колебаний (т. D) находится посередине твердого тела. Если узел колебаний и центр масс совпадают, то твердое тело теряет возможность поступательных движений и совершает только угловые колебания. При

твердое тело может совершать только вертикальные прямолинейные колебания при отсутствии угловых. Из (17) следует, что коэффициент связности амплитуд колебаний i реализуется на определенной частотеpatterns of distribution of amplitudes of vibrations of points of the working body. Thus, for the cases shown in FIG. 5 by coordinate

the mode of dynamic vibration damping is implemented; according to FIG. 5, b - vibration mode along the coordinate

... FIG. 5, c and d, the vibration modes are shown when the vibration node (point D) is between point. A and B, which implies the possibility of angular oscillations together with translational movements. If the condition is met

the vibration node (point D) is in the middle of a rigid body. If the node of vibrations and the center of mass coincide, then the rigid body loses the possibility of translational movements and performs only angular vibrations. When

a rigid body can perform only vertical rectilinear vibrations in the absence of angular vibrations. It follows from (17) that the connectivity coefficient of the oscillation amplitudes i is realized at a certain frequency

Using (23), one can estimate the possible types of distribution of amplitudes at each of the frequencies of the external disturbance, taking into account the parameters of the systems. The connectivity coefficient a is taken into account in the structure of expression (9) through the coefficients A and B (expressions (17 '), (17' ')). If we accept that

then the parameter i will depend on the frequency of the external influence; for a given i and system parameters, the frequency is determined by expression (24).

9. Control of the dynamic state of the vibrating working body can be realized by installing only one vibration exciter, which generates a concentrated force. Theoretical studies show that the concentrated force applied at some point of the working body (in this case, i.e., E)

. Используя значения α, а также значения i как коэффициент межпарциальной связности координат, можно определить положение характерных точек и частот колебаний, которые определяют особенности динамических состояний вибрационного органа, представленных на фиг. 5, а также режим отсутствия угловых колебаний:can be replaced by a dynamically equivalent system of two forces, which will be spaced along the coordinates y ₁ (A ₁ ) and y ₂ (B ₁ ). In the considered case of equivalent transformations, the resulting system of two coupled forces. The connectivity coefficient of these forces is determined by the formula

... Using the values of α, as well as the values of i as the coefficient of interpartial connectivity of coordinates, it is possible to determine the position of the characteristic points and vibration frequencies that determine the features of the dynamic states of the vibrating organ, shown in Fig. 5, as well as the mode of absence of angular vibrations:

и

вполне доступны при визуальном доступе или могут определяться с помощью обычных вибродатчиков с последующей обработкой информации в блоке управления.Conclusion. The proposed method for controlling the dynamic state of a vibrating technological machine is simple to implement, since the required distribution of the vibration amplitudes of the points of the working body is determined by the parameters of the design and technical performance of the machine available for evaluation. Coefficients of connectivity of coordinates of motion

and

are quite accessible with visual access or can be determined using conventional vibration sensors with subsequent processing of information in the control unit.

A method is proposed that allows to build mathematical models based on technologies of structural mathematical modeling. The used structural mathematical models provide the necessary transfer functions and functions of interpartial relations. All necessary data can be obtained on the basis of analytical calculations with known parameters of the technological system.

The proposed methodological basis makes it possible not only to obtain data on the choice of the place of application of the vibration exciter, but also to assess the possibilities of the scale of changes in the dynamic state of the working body, including through the frequency characteristic equation, and also to determine the location of the nodes

oscillations of working bodies with the allocation of parameters that adversely affect the stability of the system.

Bibliography

1. Kopylov Yu.R. Dynamics of vibroimpact hardening processes: monograph / Voronezh: IPC "Scientific book", 2011. - 569 p.

2. Eliseev S.V., Artyunin A.I. Applied theory of oscillations in problems of dynamics of linear mechanical systems / S. V. Eliseev, A.I. Artyunin. - Novosibirsk: Nauka, 2016 .-- 459 p.

3. Eliseev A.V., Selvinsky V.V., Eliseev S.V. Dynamics of vibrational interactions of elements of technological systems, taking into account unstoppable connections. - Novosibirsk: Nauka, 2015 .-- 332 p.

4. Loytsyansky, A.I. Lurie. Theoretical Mechanics Course. In 2 volumes, L.G. - T. 2 .: Dynamics. M .: Bustard, 2006. - 7th ed., Rev. and add. - 719 p.

5. Eliseev S.V. Applied system analysis and structural mathematical modeling (dynamics of transport and technological machines: connectivity of movements, vibrational interactions, linkages): monograph - Irkutsk: IrGUPS, 2018 .-- 692 p.

Claims (1)

A device for controlling the dynamic state of a vibration technological machine containing a solid body on elastic supports, a vibration exciter, sensors, servo drives with lead screws, characterized in that lead screws and servos are additionally installed on top of the working body along its entire length to move along it a vibration exciter located in the center.

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