Industrial electric drives used in various systems and mechanisms are based on converting the frequency of three-phase AC mains. Such conversion is necessary to control the actuator parameters, i.e. performance or speed. One option consists in direct conversion of electricity without using an intermediate DC link, i.e. direct conversion. In this case, the input voltage from the power supply is converted into the output voltage of required frequency. The researcher-designed two-channel converter provides high-quality output voltage without filtering, which reduces the cost of an electric drive. One of the ways to develop and improve an electric drive lies in increasing the number of motor phases. This paper proposes a six-phase electric drive that performs direct conversion and offers a number of technical advantages.

AC-multiphase Adjustable Electric Drive with Two-channel Conversion

Large sea ships take a huge part in world trade, passenger transport and providing supply to remote areas. There are various ship classes, designed not only for transportation of goods, but also to perform special tasks. The mentioned type of ships includes icebreakers designed to support navigation in the Arctic region. They are distinguished by a large displacement and high-capacity propulsion plant, as well as a dynamic mode of operation with frequent reverses. Many other ship types also use an electric drive in their propulsion systems, which is due to operating conditions and reliability requirements. Electric propulsion systems have the ability to change the direction of rotation with frequent repeated cycles. Currently, AC electric propulsion systems are used most widely, replacing obsolete DC motors. With a retrospective view of electric propulsion systems, a sequential development becomes obvious. The modern marine electric drive should be further improved in terms of its capacity and operation cost-effectiveness. The last of these tasks is mainly to increase efficiency and reduce losses both when converting the frequency of the supply voltage and in general in all parts of the electric propulsion system. In practice, with the modern development of technology, the reserve for improving properties of electric components is not so great. In this case, the single way to increase the efficiency of shipboard electric propulsion systems is reducing the number of functional units on the way from ship generators to the engine motor. The authors proposed a number of technical solutions for improving ship electrical propulsion systems; the novelty is confirmed by patents for inventions. One of the solution effects is the simplification of the functional circuit of the electric propulsion system, which corresponds to the general development trend- a decrease in the number of functional units and elements on the way from the ship energy source to the electric engine.

Evolution and Development Prospects of Electric Propulsion Systems of Large Sea Ships

Accidents in which aircrafts veered off the runway when landing have occurred frequently, which pose a considerable threat to people’s lives and property. Friction, produced by the contact patch between the tires and the runway, has long been known as a crucial factor for a safe landing. Therefore, accurately measuring the friction coefficient (F-Coe) is regarded as an effective means to reduce accidents, especially in extreme weather. This review article aims to summarize and analyze the state-of-the-art techniques of runway friction characteristics measurement to provide all stakeholders a broader understanding and more valuable references. First, the methods available for measuring (or estimating) the friction characteristics are reviewed, such as American Society of Testing Materials (ASTM) standard test, the caused-based method, the effect-based method, modeling method, and fusion method. Second, the pros and cons of these methods are discussed from two aspects: conventional method and the tribo-system-based method. Third, the research progress of the correlation between the F-Coe obtained by ground measurement equipment and the aircraft braking F-Coe (ABF-Coe) is summarized and discussed. Finally, the measurement policies, about runway surface friction characteristics, proposed by International Civil Aviation Organization (ICAO), Federal Aviation Administration (FAA), and European Aviation Safety Agency (EASA) in recent years are summarized and the measurement methods are proposed or improved according to these policies. For developing better and proper measurement methods of runway F-Coe (RF-Coe), the future envisaged research lines should focus on the new measurement techniques and methods under the joint action of tires, runway, contaminants, and atmospheric condition.

Techniques and Methods for Runway Friction Measurement: A Review of State of the Art

In today’s developing technology, industries are playing important role for the betterment of life and society. But in industries many functions are running under hazardous conditions, so demand of human free interaction arises, which can be fulfilled by robotics. In Chemical, Oil & Gas, Petrochemicals and many manufacturing industries today we need human safety on head, and it can be done by robots. This paper implies such type of mobile robot which can be used in complex industries. The work is based on Image processing and Centroid Algorithm. The physical quantities like (temperature, pressure, humidity, stress, PH) and leakage of gases and liquids, fire, spark and many human safety related things which can be encountered by this mobile robot. By using this robot, the main achievement is human safety and simultaneously cost effective, precision and all far away data can be easily available through IoT (Cloud)[1]. Also, it works without any disincentive at particular of desired time in day or night, where particular place requires physical quantities measurement. In this project the main components are Controller (Raspberry Pi), Four DC Motor for each wheel, Pi Camera for image detection and processing, motor driver logic and physical quantities sensor[2].

Control of Wheeled Mobile Robot Using Centroid Algorithm

Adaptive robust control of a multi-degree-of-freedom mechanical plant with resilient properties

In this paper it is considered the technique design and algorithms for friction testing measuring implementation that are based upon the simulation of the real aircraft breaking modes while takeoff and landing via the measuring wheel Moreover, the design problem of the controlled electromechanical simulator of the measuring wheel braking modes for the towed measuring vehicle is considered and adequate model implementation for the increasing the efficiency of the measuring system that consider the resilient behavior of the pneumatic tire and gearing system of the towed vehicle, and non-linear Coulomb friction with Stribeck effect Effectiveness increasing of the braking modes simulation is provided using the neuro fuzzy control system Real aircraft braking modes' simulator will provide the friction measuring results that will correlate with the real-life aircraft braking modes' characteristics

On correlation between the airport runway friction coefficient measurement results and the real-life aircraft take-off and landing braking Characteristics

In recent years, semiconductor converters are widely applied in marine electric power systems. Semiconductor converters are used in ship electric propulsion systems consisting of shaft generator units, a variable frequency drive, and alternators. The use of semiconductor converters results in decrease of power quality in ship networks, in particular, in an increased ratio of non-sinusoidal voltage waveforms (harmonic distortion). Rules of the Russian Maritime Register govern the maximum allowable distortion in the power network for a correct functioning of ship equipment. Improvement of power quality is achieved with a variety of methods including application of filter-compensating devices, three-winding transformers, and electromachine converters. The paper analyzes a single marine power system and circuit solutions for reducing the ratio of harmonics in ship networks.

Issues of electromagnetic compatibility of electric equipment on ships with electric propulsion systems

This paper describes the control problem of a multi-degree nonlinear mechanical plant with an unknown disturbance. An unknown disturbance is represented as output of a linear autonomous model with unknown constant parameters. To solve the problem of adaptive disturbance compensation, an adaptive observer of external disturbance was applied. In this paper is proposed an algorithm of nonlinear robust control of a Lagrangian plant, synthesized on the integrator bypass method, combined with the evaluation of an adaptive disturbance observer. The simulation of the designed nonlinear robust control with an adaptive disturbance observer was held using MATLAB/Simulink.

Robust Control of Multi Degree-of-freedom Mehanical Plant with Adaptive Disturbance Compensation

This paper discusses the problems of synthesis of control of multi-degree-of-freedom (multi-DOF) nonlinear mechanical plants in conditions of parametric and functional uncertainty. Nonlinear adaptive control systems are developed and investigated, synthesized on the basis of two approaches: on the basis of the exact method of backward traversal of the integrator with modified adaptation algorithms with the so-called parametric projection, and also on the basis of the approximate method of majorizing functions. A comparative study is carried out by modeling the developed adaptive systems for a complete nonlinear mathematical model of a three-DOF manipulation arm using MATLAB/Simulink software.

V. N. Sheludko

Papers

On correlation between the airport runway friction coefficient measurement results and the real-life aircraft take-off and landing braking Characteristics

Issues of electromagnetic compatibility of electric equipment on ships with electric propulsion systems

Robust Control of Multi Degree-of-freedom Mehanical Plant with Adaptive Disturbance Compensation

Adaptive robust control of a multi-degree-of-freedom mechanical plant with resilient properties

Multi-degree-of-freedom Nonlinear Mechanical Plant Adaptive Control