RU2751169C1 - Method for control of the dynamic state of a vibrational technological machine - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to vibration engineering and can be used in improving and creating vibrational technological machines. The invention is characterised by introduction of additional dynamic links into the structure of the system which is implemented on the basis of a linkage mechanism characterised by a possibility to change the mass-inertial and elastic characteristics of the system as a whole, which is achieved by making corresponding changes in the gear ratio of the linkage mechanism, achieved by moving the lever rotation unit with lead screws actuated by drives located on the supporting surface and controlled using information received from vibration sensors installed on the working body. The apparatus can be implemented and operated in automatic mode and in technology for preliminary manual technological configuration.

EFFECT: invention ensures control of the dynamic state of a vibrational technological machine by adjusting the gear ratio of the linkage connecting additional mass-inertial elements.

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Description

The invention relates to vibration technology and can be used to improve and create vibration technological machines.

Surface treatment of parts of complex shapes in vibration interactions with a free-flowing abrasive or granular medium in recent years has become widespread in many industries: processing of turbine blades, cases of complex shapes, engine blocks, rotor shafts, etc. The basics of this kind of processes were developed by domestic scientists A.P. Babichev. ., Goncharevich I.F., Blekhman I.I., Panovko G.Ya., Kopylov Yu.R. and others, which is reflected in scientific publications and is developing as one of the modern trends in the technological basis of modern mechanical engineering.

Vibration technological processes are implemented with the help of vibration technological machines, most often such equipment is created as vibration stands that have the ability to form and control the dynamic states of the working bodies that form the spatial forms of the distribution of the vibration amplitudes of the points of the working body in the form of vibration fields. The arising processes of vibration interactions of a granular (abrasive or granular) medium are distinguished by the complexity of the forms, the parameters of stable modes, the alternation of forms of contact of the working medium with the object being processed, which requires the development and implementation of methods and means of controlling vibration interactions, controlling their shape, maintaining certain modes due to special control systems.

Correction and adjustment of vibration interactions can be carried out on the basis of visual control methods by means of appropriate adjustments, and also carried out using automatic control systems, which initiates the search and development of appropriate approaches related to the creation of mathematical models, information processing algorithms and assessment of the effectiveness of control actions.

The formation of dynamic states created using controlled vibrators and vibration exciters is one of the main tuning methods. At the same time, in recent years, methods of tuning, correction, control and formation of dynamic states have been widely used by introducing additional connections into mechanical systems, the possibilities of changing the values of some parameters of kinematic or dynamic interactions. To implement tuning and correcting functions, as a rule, it becomes necessary to develop appropriate algorithms for changing and controlling dynamic states. This requires the creation of appropriate mathematical models, the construction of calculation schemes and the formation of a certain methodological basis that ensures the adequacy of the calculated positions.

A number of well-known technical developments have developed promising approaches that initiate the choice of rational solutions and the search for promising innovations.

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

Known invention [Antipov V.I., Antipova R.I., Koshelev A.V., Dentsov N.N. "Vibration conveying machine", 2532235, IPC V06 V1 / 00, priority 27.10.2014], which is a vibration conveying machine, including a working body connected by an elastic connection to the reactive part, carrying a means for communicating resonant unidirectional vibrations, and shock absorbers of low stiffness, moreover, the means for communicating resonant unidirectional vibrations is made in the form of at least a pair of identical parametric vibration exciters mounted on the reactive part of the machine, installed with the possibility of rotation of the rotors of inertial elements in opposite directions in vertical planes and driven in rotation from independent electric motors, and the resonant frequency of the means for the communication of resonant unidirectional oscillations is determined from the relations ω = λ ₁ + λ ₂ , λ ₁ = ν⋅ω, 0 <ν <1, where ω is the average value of the partial angular velocities of the rotors, λ ₁ is the effective natural frequency of the swinging pendulums of the rotors inertial elements ov, λ ₂ = √C / M _pr - partial natural frequency of the working body, corresponding to the antiphase form of unidirectional free vibrations, M _pr = M ₁ M ₂ / (M ₁ + M ₂ ) - reduced mass, C - elastic bond stiffness, M ₁ - the mass of the working body, M ₂ - the total mass of the reactive part of the machine. The technical result is the achievement of high stability of the resonant mode of operation of the machine with a high quality factor of its oscillatory system, and, as a result, the creation of energy-saving vibration transporting machines.

The disadvantages of this invention include an insufficiently detailed mathematical description of the arising dynamic effects, as well as the complexity of the control system for the dynamic state of the vibration machine.

A known method of implementing the electromagnetic drive of the asymmetric vibration movement of the oscillatory mechanical system [Kreinin GV, Matseevich BV, Mikhailov VD, Serikov VV, Ushankov AE, Yanbulatov R.I. "Device for controlling the vibration field of a technological machine", 2091183, IPC V06V 1/04, priority 27.08.1997], which consists in ensuring the acceleration mode of the armature fixed on the moving part of the oscillating mechanical system to the specified maximum value of the vibration amplitude due to the formation of force pulses by the stator , fixed on the stationary part of the oscillatory mechanical system, repetition of the acceleration mode when the amplitude of oscillations falls to a given minimum value, and the direction of the force impulses during the acceleration mode coincides with the direction of movement of the armature, characterized in that the vibration movement is carried out in the modes of acceleration, deceleration, quasi-acceleration and quasi-braking, combining or alternating these modes, and force impulses are formed by repulsing the armature from the stator in any operating modes, and the drop in the armature vibration amplitude to a specified minimum value is provided in the braking mode of operation due to the formation of force impulses from the direction by action opposite to the direction of movement of the armature or in a quasi-braking mode due to the formation of force impulses, the direction of action of which in most of the action time is opposite and to a lesser extent coincides with the direction of movement of the armature, and in the quasi-acceleration mode, force impulses are formed, the direction of action of which in a smaller part of time the action is opposite, and in large it coincides with the direction of movement of the armature, switching to braking or quasi-braking modes when the specified maximum value of the armature oscillation amplitude is reached.

The disadvantages of this analogue are the lack of a mathematical model that explains the physical nature of the emerging dynamic effects, as well as the complexity of changing the dynamic state of the vibration machine.

A known device is a vibration installation for pre-sowing seed treatment [Serga G. V., Reznichenko S.M. "Vibrating installation for pre-sowing seed treatment", 2580152, IPC А01С 1/00, priority 03/10/2016], containing a grinding drum with an unloading window, a metering hopper, an unloading chute, resiliently installed on the base. The grinding drum is made conical, rigidly installed horizontally and mounted from three or more trapezoidal strips with different widths, increasing their length, on which alternately from their opposite sides at an angle of 60 ° to the axis of the strips are made by milling or pressure treatment of the zone a weakened section in the form of cuts with beveled walls, for the formation of polyhedral surfaces along the perimeter of the conical helical grinding drum from triangles alternately arranged with their lateral sides. In this case, the strips are twisted in the longitudinal direction relative to their longitudinal axes and are bent in the transverse direction along a helical line on a conical mandrel, with the formation of three or more helical lines and helical surfaces of the main and opposite directions along the perimeter of the helical grinding drum with a variable, increasing pitch of helical lines. The device allows you to simplify the design and expand its technological capabilities.

The main disadvantage of this invention is the complexity of the control of the dynamic state of the vibration technological machine. There is also no mathematical description.

The prototype is a device for vibration abrasive processing of cylindrical parts [NV Mategorin, AP Babichev, PD Motrenko, G. Chumachenko. "Device for vibration abrasive processing of cylindrical parts", 74333, IPC В24В 31/067, priority 27.06.2008], containing a base on which a container with an inertial vibrator is installed by means of springs, equipped with means for loading and unloading parts, means for transportation of parts in the process of abrasive processing, containing transport channels arranged in layers under each other, characterized in that the means for transporting parts during abrasive processing contains at least two removable working transport trays, parallel and inclined to the horizontal plane, made in the form of a rectangular trough, the bottom of which is provided with an abrasive coating, between the working transport trays, a transport tray is installed, which has an angle of inclination to the horizontal plane in the direction opposite to the slope of the working transport tray, and each working transport tray is connected to the feed and discharge systems cm coolant (coolant).

The main disadvantages of the prototype include the complexity of controlling the system of stiffness parameters, as well as the choice of the optimal position of the additional connection.

The objective of the present invention is to control the dynamic state of a vibrating technological machine by adjusting the gear ratio of the lever link connecting additional mass-inertial elements.

A device for controlling the dynamic state of a vibration technological machine, which is a system consisting of a working body mounted on a supporting surface and connected to it through elastic elements, containing a pivot joint connected to a lever mechanism, sensors installed on both sides of the working table, and a mass inertial elements resting on elastic elements connected by a lever mechanism, characterized in that the pivot joint is mounted on the cradle with the ability to move by means of the drives on which their control units are installed, the lever mechanism with variable arms provides the required vibration mode.

The essence of the invention is illustrated by drawings.

FIG. 1 shows a schematic diagram of a vibratory technological machine with an elastic-lever device for controlling the dynamic state of the working body, containing a supporting surface 1, a pivot joint 2, a cradle 3, a lead screw 4, drives 5, 20, information processing and control units for drives 6, 19, elastic elements 7, 11, 16, 18, mass-inertial elements 8, 17, arms of the lever mechanism 9, 9 ', communication channels 10, 15, 21, working body 13, vibration-measuring type sensors 12 and 14.

FIG. 2 illustrates the design diagram of the original vibratory technological machine in the form of a mechanical vibrational system.

FIG. 3 shows a block diagram of a dynamically equivalent automatic control system.

The invention works as follows.

- длины плеч рычагов рычажного механизма 9, 9'.The physical model of a vibration machine that implements the proposed device for adjusting, correcting and forming the dynamic state of the working body is a mechanical vibrational system with three degrees of freedom. The movement of the system is described by the coordinates γ ₁ , γ ₂ , γ ₁₀ and γ ₂₀ . The latter is connected through a lever mechanism with the coordinate γ ₁₀ through the relation γ ₂₀ = γ ₁₀ i ₁ , where

- the length of the arms of the levers of the linkage mechanism 9, 9 '.

Центр масс системы (т. О) размещен на расстояниях

от концов твердого тела (тт. А₁, В₁) соответственно.Mechanical oscillatory system (Fig. 1) contains a working body 13 (solid body with mass Mi and moment of inertia J relative to the center of mass - m. O). Excitation of system vibrations is performed by a harmonic vibration exciter (shown as a force Q applied at point O). Point O ₁ is shifted from T. O to the shoulder

The center of mass of the system (m. O) is located at distances

from the ends of the solid (vols. A ₁ , B ₁ ), respectively.

Ходовой винт 4 приводится в движение от приводов 5 или 19 (один из них резервный).The working body 13, including A ₁ , B _1, rests on elastic elements 11 and 16, which have stiffness coefficients k ₁ and k ₂ . The system has a built-in lever mechanism (arms 9, 9 '), which has a connection with a pivot joint 2, which can move along the guides (lodgment 3, having a dovetail connection). The pivot joint 2 can be moved over the cradle using the lead screw 4, which provides a change in the gear ratio of the lever

Lead screw 4 is driven by drives 5 or 19 (one of them is spare).

The mechanical oscillatory system also has additional mass-inertial elements 8, 17 with masses m ₁ and m _2, respectively, resting on elastic elements 7, 18 with stiffness coefficients k ₁₀ and k ₂₀ connected to the support surface 1, including A ₀ and B ₀ respectively. The dynamic state of the working body is assessed by vibration-measuring sensors 12 and 14, which transmit information signals through communication channels 10, 15, 21 to the information processing and drive control units 6, 20.

The system parameters for the implementation of the technological mode are calculated in advance, the system is put into operation; dynamic state parameters are monitored by sensors and control units. If necessary, the drives are set in motion by the rotary joint 2, which changes the gear ratio i and makes appropriate corrections in the formation of the vibration field.

Theoretical justification

1. To construct a mathematical model in the coordinates γ ₁ , γ ₂ , γ ₁₀ , a technology is used based on the application of the Lagrange equations of the second kind, taking into account the specifics of construction, characteristic of methods of structural mathematical modeling in accordance with [1]. To describe the motion, the coordinate system γ ₁ , γ ₂ , γ ₁₀ , associated with a fixed basis, is used. The following ratios are used in the calculations:

Where

от центра масс (т. О фиг. 2).The working body is considered as a rigid body with a mass M and a moment of inertia J, performing a plane oscillatory motion. The center of mass of a rigid body is located at point O (Fig. 1), external excitation in the form of a monoharmonic force Q is applied at point O ₁ (Fig. 1) at a distance

from the center of mass (i.e., Fig. 2).

In general, the design diagram (Fig. 2) of a technical object is a mechanical oscillatory system with lumped parameters with three degrees of freedom. In the structure of the system, a lever mechanism is used, which ensures the movement of additional weights m ₁ and m ₂ at the ends of the elements of the lever mechanism in tt. A, B. The linkage has a center of rotation at point O ₂ , which can change its position and accordingly vary the value of the gear ratio

- размеры плеч рычажного механизма 2 -го рода [2].Where

- the dimensions of the arms of the linkage mechanism of the 2nd kind [2].

The presence of the gear ratio i predetermines the relationship between the coordinates γ ₁₀ and γ ₂₀ in accordance with the current value.

It is assumed that the mechanical oscillatory system (Fig. 2) performs small oscillations under the action of an external disturbance Q relative to the position of static equilibrium.

The expressions for the kinetic and potential energies in the case under consideration have the form

Using relations (1), we write (4), (5) in the form

Using the methodological techniques outlined in [1], we obtain in the time domain the following differential equations

After Laplace transforms with zero initial conditions, the system of equations (8) - (10) in operator form can be represented as:

In equations (11) - (13), it is assumed that p = jω is a complex variable, the <-> sign above the variable means its Laplace image [3, 4].

2. In the resulting system of equations (11) - (13), we can exclude the variable γ ₁₀ , assuming that

Where

Taking into account (14), the system of equations (11) - (13) can be reduced to

mind

The structural diagram (or structural mathematical model) of the system is shown in Fig. 3.

внешнее воздействие распределяется по двум входам и действует одновременно. Упругие связи и связи между парциальными блоками носят специфический характер.The structural diagram (Fig. 3) displays the features of the system, which are that in the coordinate system

external influence is distributed over two inputs and acts simultaneously. Elastic bonds and bonds between partial blocks are of a specific nature.

To assess the dynamic properties of the system, the transfer function of interpartial connections can be used

where N (p) is determined by expression (15).

The transfer function (18) makes it possible to obtain, at given parameters, the amplitude-frequency and phase-frequency characteristics, which can be used to develop a technology for the formation and maintenance of the necessary parameters and structure of the vibration fields of the working body.

In particular, the transfer function (18) at high frequencies has the amplitude-frequency characteristic in mind, have a limit

A feature of the system is the fact that it becomes possible to obtain effects associated with the "zeroing" of interpartial connections. In this case, specific modes of autonomous influence on the input processes of the system are possible in a situation when the dynamic connections between the partial blocks are "turned off".

и

могут быть созданы режимы динамического гашения колебаний, когда

или

. В этих случаях распределение амплитуд колебаний по длине рабочего органа будет происходить линейно (по закону треугольника). В упомянутых случаях центр вращения (узел колебаний) твердого тела будет совпадать с тт. А₁ или В₁. При коэффициенте связности, равном +1, рабочий орган совершает только поступательные вертикальные колебания при отсутствии угловых движений. В свою очередь, при коэффициенте связности, равном -1, центр вращения (узел колебаний) будет находиться в точке, совпадающей с серединой твердого тела. Коэффициент связности может принимать и другие значения, не совпадающие с 0 или -1. В этих случаях центр вращения (узел колебаний) может находиться за пределами рабочего органа; в свою очередь, движение твердого тела будет происходить как вращение относительно узла колебаний, что соответствует распределению амплитуд колебаний по длине рабочего органа. Отметим, что при одновременном «обнулении» на одной частоте числителя и знаменателя в системе могут возникать и специфические динамические режимы.Expression (18) (transfer function of interpartial connections) can be considered as a coefficient of connectivity, reflecting the features of the distribution of vibration amplitudes of points of the working body (or solid body M, J) along its length. In particular, both the numerator and denominator of expression (17) are biquadratic equations, from which it follows that for each of the coordinates

and

modes of dynamic damping of oscillations can be created when

or

... In these cases, the distribution of vibration amplitudes along the length of the working body will occur linearly (according to the law of the triangle). In the above-mentioned cases, the center of rotation (vibration node) of the rigid body will coincide with TT. A ₁ or B ₁ . With a coefficient of connectivity equal to +1, the working body performs only translational vertical oscillations in the absence of angular movements. In turn, with a connectivity coefficient equal to -1, the center of rotation (vibration node) will be at the point coinciding with the middle of the rigid body. The connectivity coefficient can take on other values that do not coincide with 0 or -1. In these cases, the center of rotation (vibration unit) may be outside the working body; in turn, the movement of the rigid body will occur as rotation relative to the vibration unit, which corresponds to the distribution of vibration amplitudes along the length of the working body. Note that with the simultaneous "zeroing" at the same frequency of the numerator and denominator, specific dynamic modes can arise in the system.

Thus, the presence of relations for the connectivity coefficient can be considered as an algorithmic basis for ensuring the operation of the correction system, tuning, control and the formation of dynamic states of a vibration technological machine. When developing mathematical models, methods of structural mathematical modeling were used [3, 4]. Shown in FIG. 3, the structural mathematical model of a technical object can also be used (through the characteristic frequency equation) to determine the frequencies of natural vibrations (in this case, there can be three such frequencies).

List of sources used

1. Eliseev S.V. Dynamic synthesis in generalized problems of vibration protection and vibration isolation of technical objects / S.V. Eliseev, Yu.N. Reznik, A.P. Khomenko, A.A. Zasyadko. - Irkutsk: publishing house of ISU, 2008 .-- 523 p.

2. Kreinin P.G. Handbook of mechanisms. - M .: Mechanical engineering. 1986 .-- 512 p.

3. Eliseev S.V. Applied system analysis and structural mathematical modeling / S.V. Eliseev. - Irkutsk: IrGUPS, 2018 .-- 692 p.

4. Eliseev A.V., Kuznetsov N.K., Moskovskikh A.O. Machine dynamics. System views, structural diagrams and connections of elements. Moscow: Innovative mechanical engineering, 2019.381 p.

Claims (1)

A device for controlling the dynamic state of a vibration technological machine, which is a system consisting of a working body mounted on a supporting surface and connected to it through elastic elements, containing a pivot joint connected to a lever mechanism, sensors installed on both sides of the working table, and a mass inertial elements resting on elastic elements connected by a lever mechanism, characterized in that the pivot joint is mounted on the cradle with the ability to move by means of the drives on which their control units are installed, a lever mechanism with variable arms, which ensures the required vibration mode is obtained.

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