Моделирование системы управления электроприводом подъема экскаватора ЭШ 20.90 при работе в тяжелых горнотехнических условиях

Dragline excavators are the main means of mechanization in mining coal fields. The operational reliability and in-use performance of the overburden dragline excavators determine the mining enterprises’ capacity. The aim of the study is to increase the reliability of the excavators’ electromechanical equipment. The main research method is modeling of the electromagnetic processes taking place in the after-repair tests of the excavator’s electric machines. The study has shown that the failures of the mining equipment operating in the northern part of Russia are of both mechanical and electromechanical nature. The failures associated with electromechanical emergency conditions are more often caused by the failure of the direct-current electric machines of the excavators’ main drives. To ensure the high quality of the repair and reduce the risk of failure, all electrical machines must undergo appropriate post-repair tests including those under load. The existing loading methods involve mechanical aggregation of the electric machine with the load devices. It is difficult to implement these methods when testing large direct-current electric machines in the conditions of the repair plants. Obviously, the development of the test methods that exclude mechanical aggregation of the electric machines and load devices is important and promising. Static loading of electrical machines is proposed as one of the above methods. The method implies dividing the test in two stages. In the first stage, static current loading is performed, and in the second stage, dynamic current and mechanical loading are carried out in the modes close to operational ones. The study of the control system developed for the electric drive of the test stand has shown that the system is functional and allows the testing of the direct-current electric machines in full.

Operation delays and trip cancelations affect the reliability of the operation and customer’s satisfaction. This review work adopts a case study of AALRTS operation system employing operation data and incident records of AALRTS. The purpose of this paper is assessing the failures frequency and the time it takes to get back to its operation aiming that how sensitive it is for the reliability of the operation. An extensive literature review has been used to approach the problem in which the sensitive failure`s analysis methods have been identified. The method that has been used to investigate the failure`s magnitude was sensitivity failure analysis by considering the case study of AALRTS. The method has been implemented to identify different failure modes through the analysis of the case how sensitive the failures are to the normal operation. The results that have been discovered from the analysis are: - the safety incidents and equipment failures are the major groups that affect the normal operation of AALRTS. When we go to the depth level-crossing incidents and power outages are the major sensitive failures (from safety incidents and equipment failures) that can reduce the reliability of the operation dramatically. Finally the researcher would like to recommend that giving a due attention for those sensitive failures might improve the reliability of the railway operation.

Many coal mines in Russia tend toward increasing their production output. Chernogorsky open pit mine, having expanded output by more than 30% for the last five years, is not exclusion. As output is increased whereas geological conditions complicate, technological parameters and production efficiency change. For example, in the open pit, percentage of overburden removal with direct dumping has greatly shrunk as against the truck-and-shovel system. In the meanwhile, the cost of stripping with the tuck-and-shovel system is much higher than in direct dumping by walking excavators. This article gives an analysis of technological parameters, open pit mining system parameters and stripping arrangement at the mine. The authors examine costs of stripping machinery maintenance and compare specific capacities of equipment in use. The modeling results on further increase in productivity of the open pit mine and in capacity of walking excavators are presented with the calculated optimized height of bench for stripping with direct dumping. The reserves available to increase stripping efficiency lie, in the authors’ opinion, in the system of resource allocation for equipment operability maintenance and personnel motivation.

This study investigates the effectiveness of electronic initiation systems (EIS) for wall control blasting in open-pit mining, with a specific focus on their influence on ground vibrations and rock fragmentation. The primary objective of the study is to evaluate whether EIS can achieve comparable or superior results in fragmentation quality while reducing seismic impact compared to non-electric initiation systems (NEIS). Experiments were conducted at an open-pit gold mine. During the experiments, EIS and NEIS were used. There was assessed seismicity of each blast during the experiments. Peak Particle Velocity (PPV) was measured at multiple points near the pit benches, and fragmentation of the blasted rock mass was analyzed through visual inspection and image analysis techniques. A statistical evaluation of the collected data revealed that EIS provided similar fragmentation outcomes while significantly reducing PPV values. Due to the ability to precisely time blasts and allow for optimized delay sequences and energy distribution, EIS can reduce blast vibrations. These findings suggest that EIS is a viable and efficient solution for wall control blasting, particularly in cases where pre-splitting or other conventional techniques cannot be applied due to geological or operational conditions. In this study, for the first time,the PPV was measured at the closest distance (6.57 m to the blasted block). The authors tried to find out the combination of two controversial outcomes of blasting work, rock fragmentation and ground vibrations, in this study.

Development of control systems for fluid-based adaptive impact absorbers

Turbojet engines are nowadays mostly controlled by full authority digital engine control (FADEC) systems using electronic engine control units. Microprocessor based control systems allow application of sophisticated control algorithms. The aim of the presentation is to show the state-of-the-art control systems and perspective algorithms based on integrated situational control methodology, which are aimed to increase the efficiency, reliability, and safety of operation of turbojet engines. Situational control is applied in this case in control and management of turbojet engines under all operational conditions including atypical ones using intelligent elements and strong integration with diagnostic systems. The concept of highly integrated control and diagnostic system is leading to a novel modular control framework with morphing structure and a degree of intelligence. It will be presented for application on general turbojet engines with specific implementation tested on a small turbojet engine in laboratory conditions as a proof of concept with positive results. These algorithms are designed as modular and robust with perspective applications in control of other large scale systems.

Operating reliability assessment of instrumentation and control systems (I&Cs) is always one of the most important activities, especially for critical domains such as nuclear power plants (NPPs). It is an important source of I&C reliability information preferable to lab testing data because it provides information on I&C reliability under real use conditions. That is the reason that now it is a common practice for companies to have an established process of collecting operating reliability data on a large variety of used components on regular basis, maintaining a database with failure information, total operation time, typical failure modes, etc. The intensive use of complicated components like field-programmable gate arrays (FPGAs) in I&C which appear in upgrades and newly-built nuclear power plants makes the task to develop and validate advanced operating reliability assessment methods that consider specific technology features very topical. Increased integration densities make the reliability of integrated circuits the most crucial point in modern NPP I&Cs. Moreover, FPGAs differ in some significant ways from other integrated circuits: they are shipped as blanks and are very dependent on the design configured into them. Furthermore, FPGA design could be changed during planned NPP outage for different reasons. Considering all possible failure modes of FPGA-based NPP instrumentation and control systems at the design stage is a quite challenging task. Therefore, operating reliability assessment is one of the most preferable ways to perform a comprehensive analysis of FPGA-based NPP I&Cs. Based on information in the literature and own experience, operational vs analytical reliability could be pretty far apart. For that reason, analytical reliability assessment using reliability block diagrams (RBD), failure modes, effects and diagnostics analysis (FMEDA), fault tree analysis (FTA), fault insertion testing (FIT), and other techniques and their combinations are important to meet requirements for such systems. The paper summarizes our experience in operating and analytical reliability assessment of FPGA based NPP I&Cs.

The airports construction level is improved and the construction scale is constantly expanded with the rapid development of society, economy and science and technology, which brings a good development prospect for aircraft towing tractors. On the basis of summarizing the current research and application of aircraft towing tractors, the traction characteristics of towbar and towbarless aircraft tractors were analyzed, and the mechanical, electric, hydrodynamic and hydraulic transmission automatic control system were compared. The composition, working principle and application of hydraulic steering control system, hydraulic braking control system, hydraulic clamping and lifting mechanism and hydraulic hybrid power system of aircraft towing tractors were emphatically discussed. The results show that the configuration of towbarless traction is flexible and the traction capability is strong. Hydraulically controlled aircraft towing tractor has good traction, braking and control characteristics. Electronic hydraulic braking system is precisely controllable, and the hydraulic hybrid technology is beneficial to reduce the energy consumption of aircraft towing tractors. The demand for aircraft towing tractors is increasing with the expansion of the airport distribution and construction, on the basis of constantly improving the existing aircraft towing tractor and according to the needs of airport operation, it is necessary to adopt innovative technology to develop energy-saving, environment-friendly and intelligent aircraft towing tractors, so as to adapt the development needs of aviation industry.

Standard control systems can be characterized by type in the s-domain; typically these types are of integer order. Some of the implications of noninteger order systems in the s-domain are explored. To accomplish this, results from the area of fractional calculus, which defines mathematics of noninteger order derivative and integration, are utilized. Fractional calculus operators, Laplace transformed differintegrals are shown to behave differently from their standard integer-order counterparts. >

Design and research a sorting device for dismantling electric energy meter. The gripping mechanism of the gripping electric energy meter is designed. By moving and rotating, multiple electric energy meters can be caught to different positions, and the sorting efficiency is improved. Set up a second line body to provide multiple blanking positions for placing different fault types to solve the problem of single sorting position. The lifting mechanism and the supporting plate are set, and the lifting and lowering mechanism of the lifting mechanism is controlled by the control system, so that the electric energy meters are equidistantly classified, the beat of the unloading is controlled, and the unloading requirements of the unloading robot are met.

Energy Benefits of Electronic Controls at Small and Medium Sized U.S. Manufacturers

Development of mining in the opencast mine Drmno from Kostolac basin in Serbia is carried out in the increasingly complex geological and hydro-geological conditions with the decline of the coal seams to the alluvial part of Europe’s largest river Danube. Greater depth and inflow of groundwater significantly increase costs for dewatering facilities construction with the requirement for optimizing of this more and more important surface mining process. Making decision on screen construction in the opencast mine with redesign of line wells parameters for the defence against groundwater, in addition to geology and hydrogeology exploration activities, analyzing the elements of the opencast mining systems and a number of working environment parameters with the development of the hydrodynamic model requires necessary review of economic and environmental effects. A detailed techno-economic analysis has been done in order to demonstrate technological justification and economy of screen construction as the system for protection against groundwater in the opencast mine. The defence of the opencast mine against the groundwater without the construction of screen causes construction of several dewatering wells and lines with increased pumping capacities by the end of deposit mining. On the other hand, screen construction means big initial investments but with a smaller number of dewatering wells with reduced capacities, lower cost of electricity and larger reliability of the system operation in the long period until the closure of the opencast mine. Estimates of environmental impact and efficiency comparison between these systems options for protection against of groundwater have been done. DCF analysis has shown that the long-term averaged costs for opencast mine Drmno dewatering against groundwater per ton of coal are approximate for the both system options. Final decision on the approval of the combined dewatering system with a reduced number of dewatering wells and screen construction has been caused by the system reliability and environmental effects related to the impact on the groundwater level outside of the opencast mine boundaries and safer operation of the hydro power plant Djerdap system on the Danube River.

According to the characteristics of space missions and space environment, to slow performance deterioration and possible reliability attenuation for aerospace mechanisms, an operational reliability system control methodology is proposed in this article. A space manipulator – a kind of typical complicated aerospace mechanism – is chosen as the research object. First, considering relevant materials and structure mechanism of joint and link parts, the influence factors of operational reliability for space manipulator are divided. Then, by introducing the responding layer factors, a mapping relationship between the influence factors of operational reliability and control variables is analysed. On this basis, a new method to build a hierarchical control system of operational reliability for the aerospace mechanisms is proposed. In this method, the mechanism how the influence factors of operational reliability are introduced into the control system is defined, and an operational reliability system control model is built, which is made up of task planning, path planning, and motion control. Finally, the proposed methodology is further explained with the operational stability of a space manipulator as an example. After analysing the mapping relationship among the influence factors of operational reliability, the factors of responding layer and control variables, a multi-objective optimization method based on Nondominated Sorting Genetic Algorithm II (NSGA-II) is proposed to ensure the operation stability for a space manipulator. These optimization objectives are introduced into the optimized control model at path planning level as constraints. According to these constraints, the optimized control system can be adjusted to improve the operation stability of the manipulator, and the operational reliability is also improved during this process correspondingly. Simulation results prove the effectiveness of the proposed method.

Usually distinguish three basic stages of the movement of the lifting mechanism of the crane: start (overclocking), steady motion and inhibition (run, stop). For each of these stages of motion, certain relations between the work of the motive (or brake) forces and forces of resistance are characteristic. In particular, at the stage of starting the mechanism, it is necessary that the motive moment is greater than the moment the forces of resistance to the motion. At the same time on the shaft of the engine during the start time there is a necessary acceleration and its angular velocity increases zero to tireless value, which corresponds to the passport mode. During the frequency set to the tireless value, the proper frequency of the engine shaft rotation is a function of time. In the process of launching the lifting mechanism, a resonance arises (the engine shaft rotation frequency is equal to the intrinsic frequency of the drive-rope-load system fluctuations.) This resonance causes a significant overload of the engine in the process of recruiting a fixed frequency. reducing the dangerous overloads of the engine during its start-up, and also reducing the over-load / load factor (dynamic) to the minimum value in the elastic element of the mechanism (rope). Participating mechatronic systems for controlling the movement of the lifting mechanism and using special controllers to set the following laws of the movement of the and the load, in which the dynamic factor will be minimal. In carrying out such calculations and optimizing the dynamic loads in the ropes of the lifting mechanism, the ways of lifting the load should be taken into account: the lifting the ground , as well as the main k-nematy-force and geometric parameters of the mechanism. The purpose of this work is to establish the laws of motion of the elements of the lifting mechanism of the crane, which minimize the driving and excess moments on the shaft of the engine, as well as the dynamical coefficient in the elastic elements (ropes) of the mechanism during its start even in the presence of resonances (coincidence instantaneous the frequency of rotation of the shaft the own frequency of the system drive - rope - load). The torque characteristics of the engine are taken into account according to the Clause formula, as well as various types of dynamic resistance to the rotational motion of the engine shaft. The parameters of optimal start of the crane lifting mechanism are calculated on the basis of substantiated equivalent schemes: a) from the weight by an absolutely hard rope; b) from weight by an elastic rope; c) with picking up or from the ground. Established laws of motion, which minimize the tension of the elastic elements of the mechanism (ropes) when lifting the load, in the process of launch. The approaches and methods of classical variation calculus are used. The given results are obtained by numerical-analytical methods.

For the correct operation of hydraulic lifting mechanisms of the installation equipment of rocket and space complexes, it is necessary to ensure the synchronous movement of the rods of hydraulic power cylinders operating in parallel when performing working operations. Therefore, the urgent task is to develop synchronization systems that, along with ensuring the consistency of travel speeds, also provide the consistency of the mutual position of hydraulic cylinder rods. To solve this problem, we introduce a new approach which makes use of indirect methods for determining the working stroke of hydraulic power cylinders according to the results of measuring the angular or linear coordinates of the power elements of the mechanism. The first method is based on measuring the angular coordinates of the power elements of the lifting mechanism using angular displacement sensors - angular encoders. As for the second method, it relies on measuring the stroke of an additional link of variable length by means of magnetostrictive and cable linear position sensors. The paper briefly describes the device and the principle of operation of the sensors, and gives recommendations for the construction of measuring transducers as part of the lifting mechanism of the installation equipment. The new approach to solving the problem of controlling the stroke of hydraulic power cylinders in lifting mechanisms can be used in the development of advanced installation equipment for launch vehicles of heavy and superheavy classes.