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Arch. Min. Sci., Vol. 55 (2010), No 1, p. 217–231 217 Electronic version (in color) of this paper is available: http://mining.archives.pl ANDRZEJ OLEKSY*, ZYGMUNT SZYMAŃSKI** MODERN METHODS CONTROL AND DIAGNOSTICS OF HOISTING-MACHINES WITH APPLICATION OF ARTIFICIAL INTELLIGENCE METHODS NOWOCZESNE METODY STEROWANIA I DIAGNOSTYKI MASZYN WYCIĄGOWYCH Z WYKORZYSTANIEM METOD SZTUCZNEJ INTELIGENCJI The paper present’s an analysis of the possibility an application of chosen artificial intelligence methods in control, automatics and diagnostics systems of hoisting-machines The analysis is limited to: fuzzy logic control, genetic algorithms, and modern neural networks II and III generation methods. These methods assure realization of complicated algorithms a control of hoisting -machine with assurance of energy-saving operating conditions, monitoring of exploitive parameters, and predictive diagnostics of technical state a hoisting -machine, reducing a number of damage states. In paper present’s an idea of control system and diagnostics of machine basing on method: fuzzy- logic neuro system of the control circuit (fuzzy logic control in neural networks). In the paper present’s a chosen of control algorithms, and results of computer simulations of chosen mathematical models of hoisting -machine. Keywords: hoisting machine, artificial intelligence, fuzzy-logic control, neural net Eksploatacja maszyn transportu poziomego i pionowego stosowanych w podziemnych zakładach górniczych wymaga spełnienia warunków: energooszczędności, niezawodności oraz bezpieczeństwa pracy. W napędach górniczych wyraźną poprawę wskaźników energetycznych i ekonomicznych uzyskuje się przez: zastosowanie nowoczesnych zasilaczy przekształtnikowych sterowanych układami mikroprocesorowymi, sterowanie optymalne pracą górniczej maszyny transportowej, zastosowanie metod sztucznej inteligencji w obwodach sterowania i diagnostyki. Wprowadzenie do obwodów siłowych maszyn wyciągowych zasilaczy przekształtnikowych zapewnia budowę płynną i ekonomiczną regulację parametrów zasilania silnika napędowego. Układy zasilania są sterowane z inteligentnych sterowników wyposażonych w regulatory ACN (artificial control network). W zależności od stopnia automatyzacji stosowane są różne systemy sterowania: sterowanie rozmyte, systemy sieci neuronowych, algorytmy genetyczne. Zastosowanie techniki cyfrowej (cyfrowe regulatory jazdy, czujniki i przetworniki cyfrowe) zapewni sterowanie pracą maszyny wyciągowej w czasie rzeczywistym, przy bieżącej kontroli parametrów eksploatacyjnych. Komputery przemysłowe zapewniają monitoring oraz diagnostykę pracy maszyny wyciągowej, co umożliwi wcześniejsze wykrywanie stanów awaryjnych i zwiększy bezpieczeństwo pracy. Nowoczesne algorytmy * ** INSTYTUT TECHNIKI GÓRNICZEJ KOMAG, UL. PSZCZYŃSKA 37, 44-100 GLIWICE, POLAND SILESIAN UNIVERSITY OF TECHNOLOGY, UL. AKADEMICKA 2, 44-100 GLIWICE, POLAND 218 sterowania, uwzględniające obowiązujące przepisy górnicze, umożliwią automatyczne, suboptymalne sterowanie pracą maszyn wyciągowych (skipowych i klatkowych). W referacie przedstawiono analizę celowości wprowadzania napędów energooszczędnych do układów maszyn wyciągowych, potrzebę zastosowania metod sztucznej inteligencji w układach sterowania i diagnostyki, wybrane algorytmy i kryteria sterowania energooszczędnego, oraz koncepcję układu sterowania i diagnostyki maszyny bazującej na metodzie: fuzzy-logic neuro net control system (sterowanie rozmyte w sieciach neuronowych). Przedstawiono wybrane algorytmy sterowania oraz wyniki obliczeń komputerowych wybranych stanu pracy maszyny wyciągowej. Słowa kluczowe: maszyna wyciągowa, sztuczna inteligencja, sterowanie rozmyte, sieci neuronowe 1. Introduction The exploitation of machines of the transport horizontal and perpendicular in underground mine demands realizations of conditions: energy-savings, reliabilities and work safeties. In mining-drives the distinct improvement of coefficients: energy and economic, obtains by: application of modern supply inverters controlled with microprocessor controller, optimal control of the work a mine transportation machine, application of the artificial intelligence methods in control circuits and diagnostics. The application in power circuits of hoisting machines an inverter supply system assures the realization a smooth and economic regulation of power supply parameters driving motor. Supply systems are controlled from intelligent sensors and converters and controllers ACN (artificial control network). Depending on the degree of automation are practical different control systems: the fuzzy logic control, systems of neural networks, genetic algorithms. The application of digital technique (digital regulators of drive, sensors and digital transducers) will assure a control with the work of hoisting machine in real time, at the current monitoring of exploitive parameters. Industrial computers assure monitoring and diagnostics of hoisting -machine work, what will enable the earlier detection of damage states and will enlarge the work safety. Modern algorithms of the control enable: operative regulations of mine machine, will automatic and suboptimal control work of hoisting machine (cable lift or cage lift) In the paper present’s an analysis of advisability an application energy-saving drives to hoisting -machines system, necessity of the application an artificial intelligence methods in control and diagnostics systems, chosen algorithms and criteria of energy-saving control, and the idea of control and diagnostics system of machine, basing on methods: fuzzy-logic neuro the circuit control the system (the fuzzy control in neural networks). The paper present’s an chosen algorithms of control, and results of computer calculations a different state of the winding-machine. 2. Modern supply systems of hoisting-machine In Polish mines are applied a systems of exploitation leaning on the high concentration of the coal. It require application an effective cutting machines and reliable transportation systems: horizontal and perpendicular transport. Systems of horizontal transport should work impromptu continuous and assure continuous coal haulage to loading stations on shaft station or directly on the surface. Systems of the perpendicular transport (cable lift hoisting shafts, descend shafts) should be coordinated with the inflow of coal and with descend rides of miner. On main hoisting shafts are applied a hoisting machine drive separately-excited direct current motor, supplied 219 from rectifier supplier (Glinka, 2000; Szymański, 2003). Rated power of driving motors of the hoisting-machines attain the level: (1000-6000) kW (Szymanski. 2003). Hoisting -machines are supplied with separate of the main mine a three-phase network about rated voltage 6kV, by lowering transformer: 110 kV/6 kV, at power short circuit networks exceeding 300 MVA. A consequence, are large voltage drops of in mains hoisting machines. The application of inverter supply system causes the enlargement of the degree of the voltage and current deformation of the power supply (generating higher harmonic), large voltage fluctuations of the network as result of jump changes of reactive power, the break down commutation of supply voltage, comparatively the cheapness of the power factor (cosφ ≈ 0,55-0,60). They can affect on other drives supplied from of the same switching station, causing disturbances of their work (disturbances of the work of funs of main airing driven with synchronous motors, or drives with inductive wound rotor motors in the system of the subsynchronous cascade. For the limitation of negative results of influence an inverter distorsion on the supply network belongs: to enlarge the short circuit power of the network, to application of filters higher harmonic (static or active), and apply an compensation system of the dynamic reactive power. To the power supply of the drive motor of hoisting -machine uses the system: the single thyristor rectifier or two symmetrical rectifiers 6T in the system to parallels. The schema of the supply system of drive motor drive hoisting -machine is presented on Fig. 1. On Fig. 2 is presented an electric schematic diagram of hoisting -machine inverter supply system, instead on Fig. 3 the schema of the module bi thyristor creating supply system of thyristor rectifier. The schema of the hoisting -machine drive system with the synchronous motor is presented on Fig. 4. Fig. 1. Electric schematic diagram of the supply system of the winding-machine drive motor Supply systems assure the reversing work of hoisting machine at utilization of electric brake, assuring recuperation of electric energy to supply source. The change a direction of rotation can be realized by the change of direction an excitation current, or by the push-pull system of armature motor circuit. supply system. 220 Fig. 2. The electric schematic diagram of jnverter supply system of the hoisting machine Fig. 3. Schema of the Bi thyristor supply system 3. The analysis of advisability application of artificial intelligence methods to control systems of mine- hoisting machines The mine-transport system, this is a well ordered internally gathering of objects being found on the surface and in undergrounds of the mine, along with relations existing between these objects and their proprieties, whose the activity is subordinate to the success of the established transportation aim. The degree of productive process automations and the complex diagnostics of machines and devices is in Polish mines considerably limited (Tadeusiewicz, 1993; Kowalski, 221 Fig. 4. Hoisting machine drive system with synchronous motor 2006). Practical are applied a systems automatic system of: local stations supplying with transformer, rectifier supply system, series of belt conveyors, hoisting -machines at the transport of the coal, and partly cutting machines: wall shearer harvesters, coal planes. In the most of mines are applied a conventional solutions in which the man as the operator is necessary to starting and switch off a machines, control of exploitive parameters and to estimation of the total correctness of the work of machines of horizontal and perpendicular transport. The knowledge of the operator and his superiors, leaning on the experience, contracted in directions, and in regulations and requirements decides about the quality of the work of mine machines. The huge knowledge of the personnel of the technical mine should create the base of intelligent systems of the real-time control – KBS (knowledge based the system), leaning on computer databases and knowledge bases (Tadeusiewicz, 1993). The system KBS will make possible the monitoring of processes the real time, diagnostic of technical state a hoisting-machine, prognoses of following production cycles and the automatic control of the all industrial process or his neuralgic elements. To the realization of the expert control: superior (SECS – supervisory expert control the system), or simple (DECS – direct expert control the system) one ought to use systems of the artificial intelligence: ACN (artificial control network) and ANN (artificial neural network). To the realization of expert systems and the optimum-control we can use: the fuzzy control (Tadeusiewicz, 1993; Kowalski, 2006; Pasko & Walczak. 2007), neural networks or control systems of adaptive containing the combination of the fuzzy-logic control and neural networks with application of genetic algorithms (Kowalski, 2006) It demands application of large scale processors, quick and the great memory (Pasko & Walczak, 2007). 222 The fuzzy logic control consists in the exchange of continuous sizes master on fuzzy leaning sizes on linguistic dependences, to utilization of expert system to conclude decision (the conclude machine, the rule base, the database) and the elaboration of the continuous signal realizing come to a decision in the real control circuit. The example-schema of the fuzzy regulator FKBC (fuzzy knowledge based control) one introduced on Fig. 5. The input signal of the controller is subjected to the process of the standardization, and is then fuzzyfied in fuzzyfication process. Using the knowledge base and variable linguistic one marks sections of variable changes decision and recommended signal level of exit which after sharpening and the denormalization is given on the exit of the controller fuzzy-logic and to the executive control impromptu rational, enable different unforeseeable situations. Fig. 5. Structural scheme of fuzzy logic FKBC controller The control with system of neural networks consists in the image of the real control system with the system of neurons (intelligent decisions cells the equipped microprocessor into transducers A/C and C/A and modules of operation memory: RAM, ROM, EEPROM, joint with synapses (two-way- transmission bus connection). The process of the control consists of two stages: I stage – the education stage (insertion to the memory of the processor of the information contracted in knowledge bases and in databases, and forcing of the function of limitations), II stage – the deduction and decision undertake stage (the realization of the control process at the utilization of knowledge bases). The control system demands usages of processors about the high speed of calculations and the great operation memory, he is practical to the control of very complicated production cycles. The simplified schema of the neuronal controller is presented on Fig. 6. 223 Fig. 6. Neural set controller Control with application of genetic algorithms consists in the exchange of the real control system with the system genetic, composite from: cells, tissues, networks of connections of inter cell and superior and local decision units The single cell contains: two microprocessors, transducers A/C and C/A, transmition registers, and operation memory. The cell copies the physically definite fragment of the real control circuit. Describing according to plan dependences happening among each elements of the control circuit and the controller we build the network of connections among each cells (with genes) of the system. It makes possible this model of physical phenomena happening in the real control system. The control system require application of more microprocessor drivers and is advisable at the control of extensive and complicated processes technical and productive. The use of expert systems in control systems of mine transportation machines will assure: the energy-saving manner of the power supply and the control the work of: belt conveyors and rail transport, the running inspection of exploitive parameters, the diagnostics local and total of machines of transportation system, and optimal control with the work of cutting machines. 4. The diagnostics of the mining- hoisting-machine drive system The reliability of the work of mine transportation machine drive system with direct current motor or with induction motors depends greatly from the correct estimation of the technical state of circuits: electric, electromechanical and mechanical. The estimation can be realized impromptu total – using the central diagnostic position, or to a limited extent – using diagnostic elements installed in the machine. The total diagnostics should be move impromptu periodic (in time-limits consequential from the exploitation or after the damage of the machine) (Glinka, 2000; Szymanski, 2003). The local estimation should be realized before every actuation of the machine. Within the framework of the local diagnostics comes true the technical state: the drive motor, supply system, control and protections circuits, and effectiveness of the braking system. For the obtainment of the possibly full automation of diagnostic research of drive system: dis- 224 tribution of measuring-circuits from supply circuits, control circuits and protections circuits; the removal of supervisory- measuring circuits to multiconnector joint situated in the operator cabin, the optoelectronic separation of measuring-circuits, application of the RS-485 C interface to communication with the external computer, application of the transmission bus enable the data transmission and being up to the UIC556 mark card. The central diagnostic post controlled from main microcomputer should be equipped into devices making possible the realization of technical research: the mechanical system and the braking system. All results of measurement will be save in the microcomputer memory. The special simulation program and suitable measuring-transducers enable a realization of measurement automatic or manual. Results of calculations are presented tabular and graphic on-screen of the monitor and printed in form of the official record a diagnostic research. The estimation a technical state of the direct current motor is realized from measuring of: the isolation resistance of armature and excitation windings, estimate of sogginess degree of isolating system, resistance of the isolation of brush holder system and the commutator, and measuring a resistance of motor windings, estimate the degree of the commutation of the motor and the technical state of brushes. At detailed research we can check the bearing system of the motor and the trembling and vibrations a corps of the motor. The estimation a technical state of the direct current motor (Glinka, 2000; Głowacz & Zdrojewski, 2006), we can realized also with the acoustic method using a system of neural networks. The method consists in the teaching of the regulator of the neuronal diagnostics of normal and damage of work states on the bases of analyses a sounds generated by the driving system. The process of the diagnostics of the sound consists of the teaching process and the identification process with sampling of the Hammings window. Then, data are exchanged by the algorithm LPC, and for every category are appointive of linear prediction coefficients. From counted values of coefficients prediction built is the vector of mark. Proces of teaching and the identification leaning on algorithms of the data processing is presented on the Fig. 7, 8. The leaning classification is on the algorithm of the backward Fig. 7. The Block scheme of the teaching process 225 Fig. 8. The Block scheme of the identification of process propagation of errors, in the use to the definite neural network. Her result is relative to the value obtained on the exit-neuron. The process of identification a signal contains following stages: the registration of the acoustic signal, the partition of the sound-track, sampling, digitizer, the normalization of the amplitude, the filtration, extraction the mark, the classification. Differences between typical sounds are a result of differences in well ordered sequences. The classification bases herself on the neural network with the algorithm of the backward propagation of errors. The neural network consists of the any number of neurons (elements converting the information). Neurons are joint into network by means of connections with definite parameters (weights) modified under of the teaching process. After the realization of the teaching stage a neural network with the algorithm of the backward propagation of errors, follows the identification on the base the vector the mark of entering on entries of the neural network. If on the exit-neuron we will obtain the value 0, then the system generates as the result the normal tone. If on the exit-neuron we will obtain the value 1, then the system gives as the result the sound the damage. The method of the diagnostics worked out by the prof. Głowacz with AGH Cracow, was verified on the special model of the direct current motor containing different damages. Results of the analysis are satisfactory (Głowacz & Zdrojewski, 2006; Szklarski & Zarudzki, 2000).The estimation of the technical state a supply system is realized checking: executive elements, short circuit protections and realizing programs tested situated in the memory of the microprocessor (set in of over load protections, short circuit protections, the inspection of the continuity of supply voltage and of feedbacks driver circuits. In hoisting-machines we should make a special attention on the technical state of: catenary and equalizing wires, and the degree of the waste of brake-facings. To investigation of the degree of the waste the wire used: inductive and supersonic methods (Głowacz & Zdrojewski, 2006). Research takes part to pass before every the change mining passing the revision of machine drive 226 (Głowacz & Zdrojewski, 2006; Szymanski, 2003). To the realization of diagnostic research of the transportation machine applied a industrial controller, build on the basis of the industrial equipped computer into modules of the driver of the type fuzzy-logic neuro the net control the system. This controller can realize different functions: diagnostic, master, of communication and records. He there is used in DC and AC drives with regulated rotational speed. 5. Intelligent measuring-sensors in drive system of hoisting-machines In every mine finds several main hoisting shafts which performs the transport of the coal from transfer stations to plant of mechanical coal reshaping. This are largely cable lift shafts working in the runtime mode of semi-automatic or automatic, at the supervision of the properly trained motor-driver. For the assurance of correct work system a cable lift hoisting-machine, she must be equipped into suitable control systems of the drive motors, the regulator of the drive, the safety circuit, system of the brake shunter and the brake safety system and also in control circuits of the loading control a coal on the loading station of the cable lift, and the unloading of coal on unloading station. On transfer stations must be situated marginal sensors, sensors of the precise location of cable lift, sensors a mass of coal loaded to the cable lift. To check out of hoisting-machine duty cycle are used analogous or digital drive regulators. Input sizes of the regulator are: the signal of the rotational speed of the rotor, the linear speed of the dish, the acceleration and spurt of the cable lift. The control is realized in function of the position of the dish in the shaft. A signal proportional to way displaced by the cable lift, are signals generated by magnetic mark on lines read by sensors of the position. These signals are controlled by magnetic transducers located on suitable levels in the gliding lute. In drive part are situated a sensors controlled a temperature of the bearing system of the machine, the temperature of brake-facings, and pressures in cylinders of the shunter brake. In electric circuits should be measured values: motor excitation current, armature current, and temperature of: excitation winding, auxiliary poles, and compensatory winding. The most of hoisting-machines is driven a motors exacting foreign cooling, for that reason we should to measure the size of the expense of the air cooling in fun system. The microprocessor technique enable nowadays enlargement of sensors number situated in transportation machines (hoisting-machine cable lift or of cage) whose a function is informing about state of the waste, or about the possibility of performance a damage of drives (electric motor, system of drive transposition, bearing system, the catenary wire, capel). Most often can be used thermo-sensors: drives, motor windings, gear, brake-facings , sensors of corps twitches, and the motor shaft, electric transducers of the type LEM of current and tension voltage of motor, sensors of the degree of the waste of friction-brakes facings and cracks of the driving wheel. In the gliding lute should be installed sensors: damages of the line, the speed of dish traffic, sensor denominative the quantity and the quality of transported coal, and detectors of metal-parts transported with the coal. Signals from each sensors will be gathered in the computer data base and used by the intelligent industrial computer treat of decisions on the quality of control, reliability a work of the device, and the optimum-control with the transportation system. To estimation of corrosion, the waste and cracks of steel-thin lines and wastes of brake-facings one ought to use methods magnetically – inductive. (Kowalski, 2006; Pasko & Walczak, 2007) 227 6. The microprocessor control system of transportation machine with application of CAN controller The control of hoisting machine work assuring the realization of definite transportation task at established times of rides and with the economic drive, consist to calculation of electromagnetic torque changes in the function road or times cycle, and calculation of speeds and acceleration in the function road or times cycle. These sizes should not different from a given values, and losses of the energy occur during their at elimination should be of minimum. The duty cycle of the hoisting-machine contains: acceleration periods, drives with constant speed and brake of both electric and mechanical. Changes temporary decision sizes: driving torque, length of route, the travel speed, coal weight, give possibility the energy-saving drive at the use of methods of expert systems and adaptive control of driving motor a machine. For the complexity of procedures of adaptive control one used the algorithm of the fuzzy logic control with the driver of neural networks of II degree to marking of the value of electromagnetic torque of the driving motor a machine (Kowalski, 2006; Pasko & Walczak, 2007). The block scheme of the adaptive fuzzy leaning regulator on the model of the object is presented on Fig. 9. Fig. 9. The visual schema of the regulator fuzzy logic neuro the net control At the elaboration of the verbal description of input variables and fuzzy rules of the inference one uses the knowledge base and the database of the hoisting-machines control. Actually are applied different versions of regulators: the regulator celled TDLs (Time Delay Liner) on input 228 FFNN (Feed-Forward Neural Network), system with the repetition of processes, and real-time control. It can also apply system with the Wiener identification and linear approximation of dynamic states and non-linear approximation of static states. On Fig. 10 presented the block scheme of the mathematical model of the hoisting- cable lift machine worked out with the utilization of Matlab-Simulink and TCAD programs. Simulation model of hoisting machine contain: supply system rated voltage 110kV, lowering transformer: 110/6kV, DC motor drive hoisting machine, capacitor battery for compensation of reactive power, and drive system of the main airing fun driven with synchronous motors, or drives with inductive wound rotor motors in the system of the subsynchronous cascade. It’s simulation model is based on real existing supply system in one of polish mines.The simulation model was used to verify of validation set a FLNS regulators. Example-results of simulation calculations presented on the Fig. 11, 12, 13. Fig. 13 present’s result’s of computer simulation realized for ZG Piekary hoisting machine data Results of calculations confirmed the usefulness of ACN regulators in control systems of hoisting-machines. Fig. 10. Block scheme of hosting machine simulation model 229 Fig. 11. Time diagram of rotation Speer of the motor and electromagnetic torque during normal work state of hosting machine Fig. 12. Time diagram of rotation Speer of the motor and electromagnetic torque during damage work state of hosting machine 230 Fig. 13. Result’s of computer simulation realized for ZG Piekary hoisting machine data 7. Conclusion Application of expert control systems in control, inspections, and diagnostics of hoistingmachines demands put into each circuits of additional sensors and measuring-transducers, whose output signals will make possible the realization of the optimum-control, the running inspection of technical state a machine and the detection of possible damage states. The application of fuzzy 231 logic control permits to take into account a control process of the hoisting-machine situations not adequate in which difficulty to undertake the proper decision. The fuzzy logic control demands however import to control systems of microprocessor system and the special software. Economic impact a import of artificial intelligence methods is very profitable for normal economic conditions can however bring limited advantages in transformation References Dubois D., Guastavino C., 2007. Cognitive evaluation of sound quality: Bridging the gap between acoustic measurements and meanings, Proceedings of 19th International Congress on Acoustics – ICA07, September 2-8 2007, Madrid, Spain. Driankov D., Helledoom H., Reinfrank M., 1996. Wprowadzenie do sterowania rozmytego, WNT Warszawa. Glinka T., 2000. Badania diagnostyczne maszyn elektrycznych. Wydawnictwo Komel, Katowice. Głowacz Z., Zdrojewski A., 2006. Spectral analysis of DC motor signals supplied with DC source, Przegląd Elektrotechniczny; 82, nr 11, 76-79. Golden R.M., 1996. Mathematical Methods for Neural Network analysis and Design, MIT Press. Kowalski C.T., 2006. Application of artificial intelligence in diagnostic of induction motor, Przegląd Elektrotechniczny; 82, nr 11, 53-58. Pasko M., Walczak J., 2007. 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