Now the removed haulage system (RHS) for coal mining combines of type K103М, KА80, UKD-250, etc. on the basis of electromagnetic coupling of sliding (ECS) serially is issued. They are intended for work in lavas in length to 200 m. In connection with necessity of increase in productivity of coal mining on modern mines length of a lava can to reach 300 – 350 m. However the removed haulage systems on the basis of electromagnetic coupling of sliding are characterised by following lacks:

- impossibility of development of traction effort more than 20 t;

- the raised heating of electric drive;

- the requirement of reception of the set electromagnetic moment corresponding to dynamic and static characteristics, imposes restriction on a type choice driving the electric motor of the haulage system.

Since 2008 by the Kharkov factory «Svet Shakhtera» there was been begun a serial production of the electric drive on the basis of a differential reducer and an electromagnetic brake of sliding (EBS) [1]. In a number of scientific works necessity of modernisation of automation control system system for the removed haulage system for long lavas (more 200 m) has been proved for the purpose of irrational operating modes an exception which reduce efficiency and service life RHS and a combine as a whole [2].

1 A theme urgency

A thin layers of coal (0.6 – 1.2 m) which lie down in territory of Donetsk pool, causes necessity of application the modern excavation equipment specially intended for thin flat layers. Therefore there was been begun a serial production a coal mining combine UKD200-250 with the removed haulage system by New Kramatorsky machine-building factory in 2001. Since 2008 the structure of system of moving UKD200-250 has included the automated electric drives on the basis of electromagnetic brakes of sliding . However, the existing automatic control system (ACS) possesses essential lacks:

- absence of automatic control of rational loading distribution between giving drives that reduces speed stabilization efficiency and quality;

- absence of modern means of gathering, transfer and information processing (including for management information system of technological processes of mine);

Thus, research of the dynamic and established electromechanical processes in RHS, for the purpose of working out of actions raising overall performance automatic control of RHS is an important scientific and technical problem.

2 Communication of work with scientific programs, plans, themes

Master’s qualification work is executes during 2009 – 2010 agrees with a scientific direction of the department “Mining Electrical Engineering and Automation behalf Ruvim Leybov” of Donetsk National Technical University.

3 The purpose and problems of the research

3.1 The work purpose

Concludes in carrying out of the researches directed on increase of operational efficiency of coal mining combine UKD-250 removed haulage system based on a rational parametres substantiation of the pulling and tightening automated electric drives.

3.2 Idea of work

The idea of work concludes in the dynamic and established processes research in electromechanical system ACS – RHS – a combine, taking into account pulling and tightening drives interaction with a combine through chain traction body and on the basis of the received results engineering system of automatic control.

3.3 The main problems of the research

For object in view achievement it is necessary to solve following problems:

- to make the review and to analyse the realised researches, existing technical decisions and workings out in the field of automation the removed haulage system of coal mining combines;

- to develop mathematical model RHS taking into account factors which influence on loading of RHS's elements and a combine;

- with application of numerical methods and computer aids to carry out modelling of the processes proceeding in RHS;

- on the basis of results of mathematical modelling to establish the basic laws of occurrence of irrational operating modes;

- to prove algorithm of functioning of the modernised control system;

- to develop new ACS of RHS of coal mining combine UKD-250;

3.4 The subject of the research

Subject of research are dynamic and established electromechanical the processes proceeding in RHS

3.5 The object of the research

Object of research is automated the removed haulage system of coal mining combine UKD-250

3.6 Methodology and methods of researches

At research carrying out of automatic control system of RHS the formalized representation methods are applied basically [3]:

1) the Analytical method (integrated and differential calculus).

2) the Graphic method.

4 Prospecive scientific novelty of the received results

Scientific novelty concludes in providing of rational distribution of loadings between drives RHS by automatic control system engineering by both electric drives. In researches of processes, it is necessary to consider revolting influences, and also other factors causing occurrence of low-frequency fluctuations and self-oscillations in system. It is necessary to develop more adequate mathematical model for decisions of this problem.

5 The review of the developments and researches on a theme

5.1 At the global level

Thus the basic clearing cars which are used for coal mining, are combines with the built in removed haulage system on the basis of a frequency-operated drive [4]. The development tendency coal mining combines from leading German firm Eickhoff Bergbautechnik [5] is indicative. The RHS in these combines has been realised with use winches, i.e. the combine moved by means of the traction rope attached to the case. However gradually Eickhoff Bergbautechnik has refused from such RHS, completely having translated the manufacture in the beginning on release of removed haulage system of coal mining combine with frequency-operated engine, and then and built in.

At the coal enterprises of Ukraine and Russia combines with RHS on the basis of electromagnetic coupling of sliding have found wide application.

5.2 At the national level

The removed haulage system is applied in considered combine UKD-250 (fig. 5.1). Driving engines are accordingly taken out on main transport road (are mounted on trailer sites of the conveyor). Sprocket-wheels are applied in role of driving elements of propeller. The general chain traction body is fixed with help of swivels to the case of the car and covers both sprocket-wheels on the conveyor ends. At work a lobby in the direction of a coal mining combine the subsystem moves a working branch of a chain, and back — tightens a single branch of traction body.

Figure 5.1 — The scheme of moving process of a coal mining combine with a removed haulage system

(animation: volume — 137 KB; size — 700х226; number of shots — 7; delay between shots — 2000 ms; delay between last and first shots 6000 ms; number of repetition cycles — infinity)

At figure: 1, 2 — driving an sprocket-wheels of accordingly pulling and tightening drives of haulage system; 3, 4 — driving engines; 5, 6 — electromagnetic brakes of sliding; 7, 8 — differential reducers; 9, 10 — inductive distance sensors (speed sensors); 11, 12 — amplifiers on IGBT-transistors; АТ16 — the microcontroller of type ATmelMega 16.

The removed haulage system are the most perspective on the basis of electric variators of speed [6]. Works on creation of considered subsystems with electric regulators were realized in following directions:

1. Use of adjustable engines of a direct current with the independent, consecutive or mixed excitation.

2. Application operated electromagnetic copling of sliding and electromagnetic brakes of sliding in a combination with a differential mechanisms.

3. Use of the frequency-regulated electric drive on the basis of asynchronous electric motors with the short-circuited Rotor.

Experience of application of subsystems with the adjustable electric drive of a direct current has shown their working capacity and efficiency. However these electric motors possess a number of essential lacks: high labour input of manufacturing; large the copper expense; necessity of a permanent care of the collector device;

Electric drives with frequency converters are expensive; also they are difficult in manufacturing, have rather big dimensions. They create in a power line a hindrance in the form of the higher harmonious components of voltage that negatively affects work of other making objects in this network.

The basic lacks ECS and EBS in comparison with the frequency-regulated asynchronous electric drive with a short-circuited rotor are the insufficient efficiency and high intensity of heating. This approach differs simplicity of technical realisation and relative cheapness. Drives with ECS provide smooth regulation possibility of the traction moment and deep speed regulation of combine moving.

The mechanical characteristic of a drive with EBS is resulted in figure 5.2 which consists of rigid and soft sites [7].

Figure 5.2 — Mechanical characteristics depending from value of excitation current, A: 1 — 2; 2 — 2,4; 3 — 2,6; 4 — 2,8; 5 — 3; 6 — 3,2; 7 — 4; 8 — 5; 9 — 6.

As a current of excitation is being increased, angular speed of a target shaft will change on points a, b, c, d, f, g, h to corresponding various mechanical characteristics. If it is necessary to support angular speed of a constant, for example, at level 60 rad/sec in process of increase in the moment of resistance, it is necessary to increase a current of excitation EBS, changing its characteristics according to working points k, l, m, n, o, p, r, s, t.

The equipment of automation KD-A which has been developed in institute "Avtomatgormash" and it is applied to automation RHS. The equipment is intended for control of clearing complexes КD-80, КD-90 and КМ-103 mechanisms and combines with removed haulage system on auxiliary veins of a a combine power cable; maintenance of the set operating modes (loading and speed of moving) a combine with RHS and protection of their electric motors [9].

The Kharkov machine-building factory «Svet Shakhtera» has replaced a loading and speed regulator on an electromagnetic brake that has allowed to ensure functioning in longwalls in length to 300 m at the maximum use of possibilities of combines in 2008. It allowed to increase loading by a coal face to 3000 t a day and more, instead of loading available nowadays to 1500 t a day.

5.3 At the local level

Researches in the field of automation were carried out by such scientists as: Nikolay Bojko, Pavel Gorbatov, Vitaliy Kondrahin, Sergey Dubinin etc.

Master of DonNTU Alexey Sanchenko has realized researches on improvement of existing RHS control system, developing automatic control of both drives of haulalge system [9]. Also necessity of application of more perfect speed sensors is based in work — distance sensors.

But at composing of RHS model as a variator of speed has been accepted electromagnetic copling of sliding which possesses the lacks specified above. Besides, the developed device did not provide distribution of loadings between drives.

6 The discription of the received results of the work

The mathematical model of pulling and tightening drives on the basis of EBS For research of the processes proceeding in RHS can be described the following system of the equations (6.1):

(6.1)

где φ₁ , φ₂ — angles of sprocket-wheels rotation of pulling and tightening drives accordingly, rad;

M₁ , M₂ — resulted electromagnetic moments EBS of pulling and tightening drives, N·m;

J — the resulted moment of inertia of EBS, kg·m²;

M_H1 , M_H2 — the moments of loading of pulling and tightening drives, N·m;

M_M , a, b — constructive factor [7];

I₁ , I₂ — currents of excitation corresponding EBSes, A;

ω₀ — angular synchronous speed of EBS, rad/sec;

U_B1 , U_B1 — voltage of excitation corresponding EBSes, V;

L₁(I₁) — nonlinear inductance of winding EBS of a pulling drive, H [10];

(6.2)

L_H — initial inductance, H.

Results of modelling are depicted at fig. 6.1. We see that at a current of excitation EBS of a tightening drive I₂ = 2 A (a curve 1) start-up RHS is accompanied by excitation of slowly fading speed driving sprocket-wheels fluctuations. To occurrence of such fluctuations promotes asynchronism and not-in-phasing driving sprocket-wheels RHS. So, after drives RHS start-up and achievement of rotation driving sprocket-wheel speed of nominal value a pulling drive (a curve 5), tightening drive sprocket-wheels speed of rotation is equal to zero during 6 s. Thus there is no transportation of the bottom single branch and there is a tension of the top single branch to accumulation in it of an elastic tension. At increase in a current to 0.8 А and 1.6 А (a curve 2 and 3) the amplitude and time of attenuation of fluctuations decreases at the expense of more synchronous rotation driving sprocket-wheels at start-up RHS. However the further increase in a excitation current (more 2.4 А, a curve 4) leads to increase in the rotating moment of a tightening drive to such level, when it can provide movement of whole RHS. It causes uncontrollable dispersal of a pulling drive (a curve 6), that is stabilization of speed of combine haulage is violated.

Figure 6.1 — Graphs of RHS's starting

Thus, to reduce interaction of a haulage tightening drive with pulling or with of combine cutting drive we need to provide synchronous and inphase rotation driving sprocket-wheel.

However asynchronism rotations driving sprocket-wheels cannot be eliminated fine tuning of effort EBS of a tightening drive manually. Hence, the given problem dares with developing of such regulator which realises automatic control of a tightening drive of a combine haulage system.

7 Practical value of the received results

Results of the researches, and also developing of a control system of a coal mining combine removed haulage system have the following positive effect:

1) Developing of rational automatic control algorithm of rotation speed of both drives has allowed to exclude jerks at combine haulage.

2) Automatic control of an auxiliary drive has raised quality indicators and has released the personnel from manual operations of auxiliary drive control.

3) Loading distribution between drives leads to power consumption reduction. Except such, it also leads to decrease in a friction of traction chain body about directing. That is deterioration of a chain decreases.

4) Dynamic loadings in haulage drives are decreased. It promotes increase of reliability RHS as a whole.

8 Approbation of the work results

The following articles have been published by results of researches:

1) «Снижение динамических нагрузок в вынесенной системе подачи очистного комбайна на основе дифференциального редуктора и электромагнитного тормоза скольжения»

Authors: Sergey Gutsalyuk, Sergey Dubinin.

Source: СЕВЕРГЕОЭКОТЕХ-2010. / Сборник научных работ XI международной молодежной научной конференциии в г. Ухта совместно с ДонНТУ (г. Донецк) 20 – 23 марта — Ухта, УГТУ, 2010. — 440 с.

2) «Исследование процесса формирования усилий в автоматизированной вынесенной системе подачи при заклинивании тяговой цепи»

Authors: Sergey Gutsalyuk, Sergey Dubinin.

Source: Автоматизация технологических объектов и процессов. Поиск молодых. / Сборник научных работ X научно-технической конференции аспиратнов и студентов в г. Донецке 20 – 22 мая 2010 г., — Донецк, ДонНТУ, 2010. — 267 с.

Conclusions

There are were carried out researches and automation in removed haulage system of a coal mining combine on the basis of a differential reducer and an electromagnetic brake of sliding.

After the review of carried out researches on a theme and also existing technical decisions there was accepted the decision of RHS research and further automation on the basis of an EBS instead EMS. The deduction is confirmed by results that the most effective is the way of automatic control of both drives of haulage system — pulling and tightening

Further in master’s work I will develop the algorithm, the block diagramme and the basic electric scheme of a regulator of loading and speed. Also the basic modules of the program realising algorithm of control will be developed.

Bibliography

1. ОАО ХМЗ «Свет шахтера». Привод вынесенной системы подачи комбайна ВСПК [Electronic source] / ОАО ХМЗ «Свет шахтера» — Access mode to article: http://www.shaht.kharkov.ua/files/vspk.html

2. Поцепаев В.В. Исследование динамики и выбор рациональных параметров вынесенного привода подачи очистных комбайнов: Автореф. дисс. на соиск. уч. степ. канд. техн. наук. ИГД им. А.А. Скочинского./ Поцепаев В.В. — М., 1986. — 14 с.

3. И. Acтaшкинa. Методы исследования систем управления [Electronic source] / И. Acтaшкинa, B. Mишин — Access mode to article: http://www.inventech.ru/lib/analis/analis0017/

4. Лукачевич Ю. Разработка защиты от утечек тока в шахтах эл. сетях ЧССР и тиристорными преобразователями частоты: дисс. кандидата техн. наук: 05.09.03/ Лукачевич Юрай — Донецк, 1989. — 180 с.

5. CAN. CAN in Automation (CIA): Shearer loader mining vehicle [Electronic source] / CAN. — Access mode to article: http://www.can-cia.org/index.php?id=246&L=2

6. Горбатов П.А. Гірничі машини для підземного видобудування вугілля: Навч.посіб. для вузів / П.А. Горбатов, Г.В. Петрушкін, М.М. Лисенко, С.В. Павленко, В.В. Косарев; Під заг.ред. П.А. Горбатова. 2-ге вид.перероб. і доп. — Донецьк: Норд Комп'ютер, 2006. — 669 с.: іл.

7. Щетинин Т.А. Электромагнитные муфты скольжения. /Щетинин Т.А. — М.: Энергоатомиздат, 1985. — 272 c., ил.

8. Электрослесарю добычного и проходческого оборудования: Справочник /Под. общ. ред. В.А. Антипова; сост. Л.С. Гуревич. — 2-е изд., перераб. и доп. — Донецк: Донбасс, 1989. — 159 с.

9. Санченко А.П. Исследование переходных и установившихся процессов и разработка системы управления вынесенной системой подачи повышенной мощности: Автореф. магистерской работы. [Electronic source] / Санченко А.П. / — Access mode to article: http://masters.donntu.ru/2007/fema/sanchenko/diss/index.htm

10. Дубинин С.В. Снижение динамических нагрузок и повышение эффективности вынесенной системы подачи очистного комбайна: Автореф. дисс.. на соиск. уч. степ. канд. техн. наук. / Дубинин С.В. — Донецк, 1991 г. — 209 с.

Note

When writing this abstract the master's qualification work is not completed. Date of final completion of work: December, 1, 2010. Full text of the work and materials on work theme can be received from author or his scientific supervisor after that date.

[Autobiography]