System Identification for Control of a Bow Thruster With Brushless Motor and Shaft-Less Propeller

2018 ◽  
Author(s):  
Priyatham Sanjeeva Reddy Ramidi ◽  
Nikolaos I. Xiros ◽  
Stavros Lalizas ◽  
Anastasios Papavasileiou ◽  
Vasileios Douvris ◽  
...  
Keyword(s):  
System Identification ◽  
Magnetic Coupling ◽  
Scale Model ◽  
Medium Size ◽  
Data Series ◽  
Brushless Motor ◽  
Magnetic Couplings ◽  
Shaft Seals ◽  
The Mathematical Model ◽  
Identification For Control

In this work, a bow thruster is proposed to be used onboard small and medium-size watercraft, like motor yachts, fishing boats, patrol boats, ocean exploration vessels etc. with conventional or unconventional hull designs including displacement hull, planing hull, catamarans, SWATHs, SES, and so on. As oftentimes the case, a magnetic coupling is employed. Specifically, magnetic coupling is used to transfer torque from a brushless motor’s stator to its rotor through a magnetic field rather than a physical mechanical connection. Such magnetic coupling is very convenient for liquid pumps and as, in our case, propeller systems, since a static, physical barrier can be placed between the stationary and rotating part of the system to separate the fluid from the electrically supplied stator operating in air. Therefore, magnetic couplings preclude the use of shaft seals, which eventually wear out and fail from the sliding of two surfaces against each other. In this work, a system identification process of a rim driven bow thruster is implemented employing data series obtained by tests on a prototype scale model. System Identification leads to a black-box model of the system. The model derived can be extrapolated by grey-box modeling techniques for further design improvements. A control system for the proposed thruster is developed and validated through both computer and hardware-in-the-loop simulation, after its implementation onboard a broadly used industrial Programmable Logic Controller (PLC). The mathematical model of the bow thruster mechanism is developed and the performance is analysed by using Matlab/Simulink.

Dynamic Modeling and System Identification of a Surface Marine Vehicle for Autonomous Swarm Applications

2012 ◽  
Author(s):  
Nikolaos I. Xiros ◽  
Eleftherios K. Loghis
Keyword(s):  
System Identification ◽  
Dynamic Modeling ◽  
Electric Propulsion ◽  
Nonlinear Differential Equations ◽  
Open Loop ◽  
Scale Model ◽  
Data Series ◽  
Motion Patterns ◽  
Virtual Forces ◽  
Marine Vehicle

The scale model of a surface marine vehicle with electric propulsion by a dc motor and waterjet is built. The intention is to serve as prototype for dynamic modeling and system identification of a class of vehicles for autonomous swarm applications. A first step towards this end is to develop a mathematical model capable to adequately describe the motion of the vehicle under a variety of conditions. Such model is developed by fusing basic principles with data series obtained through a series of test basin experiments. The aim is to minimize the number and cost of sensors needed in this end, without unacceptably compromising accuracy, by employing knowledge of vehicle dynamics in order to form a customized gray-box modeling approach. A set of nonlinear differential equations, used to depict the behavior of the marine vehicle at hand are derived. This dynamic model will form the basis for applying physicomimetic approaches to control and navigation of a standalone or swarm of similar vehicles. In the physicomimetic controller synthesis approach, the control problem is tackled by the concept of virtual forces acting on the vehicle and in result generating motion patterns that are favored for a certain application, e.g. avoid obstacles and collisions. By the term virtual forces we refer to forces not actually existing but rather introduced to the system of interest through means of local-loop vehicle control. To achieve physicomimetic control one needs to effectively cancel the actual dynamics or physics to which a vehicle’s motion complies with and then impose the desired dynamics as virtual forces. In the present work, a series of open loop experiments will allow us to develop the actual dynamics of vehicle motion. At the same time, sensors will also provide active feedback required by the controllers to adjust the vehicle’s dynamic response and behavior so that it can be made compliant with an arbitrary virtual force at a later stage.

Effects of misalignment on the transmission characteristics of magnetic couplings

2001 ◽  
Vol 215 (2) ◽  
pp. 227-235 ◽  
Author(s):  
S M Huang ◽  
W L Chen ◽  
C H Yau ◽  
C K Sung
Keyword(s):  
Magnetic Force ◽  
Magnetic Coupling ◽  
Transmission Characteristics ◽  
Mechanical Contact ◽  
Assembly Tolerance ◽  
Torque Transmission ◽  
Primary Driver ◽  
Magnetic Couplings ◽  
The Mathematical Model ◽  
Good Agreement

Magnetic couplings possess no mechanical contact and permit higher assembly tolerance for transmitting torque from a primary driver to a follower by magnetic force. This paper investigates the effects of misalignment on the transmission characteristics of synchronous magnetic couplings. The misalignment can be categorized into the following three types: transverse, angular and a combination of these two misalignments. Without loss of generality, an axial synchronous magnetic coupling is adopted in the present because of its simplicity both in design and fabrication. The phenomenon and influence of shafts with assembly misalignment are described first. The mathematical model for the magnetic coupling with misalignment is then constructed for the purpose of deriving the equations governing the torque transmission and force interaction characteristics. The method of equivalent magnetic charge is employed to calculate the variations in the transmitted torque owing to each type of misalignment. Finally, a test apparatus is constructed for verifying the static and dynamic characteristics of the designed coupling under various misalignment conditions. Good agreement between numerical simulation and experimental results is obtained.

Determination of the shear force of high-coercive permanent magnets from an alloy of neodymium—iron—boron rare-earth elements of 5 mm thickness

2020 ◽  
pp. 7-10
Author(s):  
A.Ya. Krasil'nikov ◽  
A.A. Krasilnikov ◽  
D.V. Taranov
Keyword(s):  
Rare Earth ◽  
Shear Force ◽  
Permanent Magnets ◽  
Magnetic System ◽  
Magnetic Coupling ◽  
Magnetic Systems ◽  
Neodymium Iron Boron ◽  
Magnetic Couplings ◽  
Standard Calculation

The possibility of applying the standard calculation of the shear force of thin high-coercive neodymium— iron—boron permanent magnets in magnetic systems and magnetic couplings is considered. A correction factor is proposed for calculating the shear force in systems with thin magnets, which allows at the stage of developing sealed equipment to calculate the shear force of permanent magnets in these systems. Keywords: magnetic system, magnetic coupling, permanent magnet, shear force. [email protected]

scholarly journals MODELING OF DISTURBANCES IN STUDY OF CONTROL SYSTEMS

2020 ◽  
Vol 2020 (4) ◽  
pp. 70-79
Author(s):  
Mikhail Vasilevich Lyakhovets ◽  
Georgiy Valentinovich Makarov ◽  
Alexandr Sergeevich Salamatin
Keyword(s):  
Control Systems ◽  
Generating Functions ◽  
Special Functions ◽  
Computer Training ◽  
Full Scale ◽  
Analytical Models ◽  
Scale Model ◽  
Data Series ◽  
Dynamic Databases ◽  
Natural Data

The article is devoted to questions of synthesis of full-scale - model realizations of data series on the basis of natural data for modeling of controllable and uncontrollable influences at research of operating and projected control systems, and also in training systems of computer training. The possibility of formation of model effects on the basis of joint use of multivariate dynamic databases and natural data simulator is shown. Dynamic databases store information that characterizes the typical representative situations of systems in the form of special functions - generating functions. Multiple variability of dynamic databases is determined by the type of the selected generating function, the methods of obtaining parameters (coefficients) of this function, as well as the selected accuracy of approximation. The situation models recovered by generating functions are used as basic components (trends) in the formation of the resulting full-scale - model implementations and are input into the natural data simulator. The data simulator allows for each variant of initial natural data to form an implementation of the perturbation signal with given statistical properties on a given simulation interval limited by the initial natural implementation. This is achieved with the help of a two-circuit structure, where the first circuit is responsible for evaluation and cor-rection of initial properties of the natural signal, and the second - for iterative correction of deviations of properties of the final implementation from the specified ones. The resulting realizations reflect the properties of their full-scale components, which are difficult to describe by analytical models, and are supplemented by model values, allowing in increments to correct the properties to the specified ones. The given approach allows to form set of variants of course of processes on the basis of one situation with different set degree of uncertainty and conditions of functioning.

Experiment and Analysis of Squirrel Cage Asynchronous Magnetic Coupling

2011 ◽  
Vol 464 ◽  
pp. 28-32
Author(s):  
Chao Jun Yang ◽  
Hong Wei Gu ◽  
Jing Jing Wang ◽  
Ru Yu Ma ◽  
Zhi Teng Li ◽  
...  
Keyword(s):  
Skin Effect ◽  
Magnetic Coupling ◽  
Experimental Results ◽  
Transmission Performance ◽  
Squirrel Cage ◽  
Magnetic Couplings ◽  
Better Than

Transmission performances of some squirrel cage magnetic couplings, which were different in magnet pole number, slot number, slot depth or slot area, were tested. Experimental results and analysis indicate that these parameters (magnet pole number, slot number, slot depth and slot area) all affect transmission performance of a squirrel cage magnetic coupling. In these factors, deep slot can not only increase slot area to improve a squirrel cage magnetic coupling’s transmission performance, but also can make skin effect on conducting bars more obvious to further improve the transmission performance. Therefore, slot depth affects transmission performance of a squirrel cage magnetic coupling greatly. The experimental results show that a deep slot squirrel cage magnetic coupling’s transmission performance is much better than a common one.

Case-Based Reasoning and System Identification for Control Engineering Learning

2008 ◽  
Vol 51 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Perfecto Reguera Acevedo ◽  
Juan JosÉ Fuertes Martinez ◽  
Manuel Dominguez Gonzalez ◽  
Roberto Garcia Valencia
Keyword(s):  
System Identification ◽  
Case Based Reasoning ◽  
Control Engineering ◽  
Identification For Control ◽  
Case Based

scholarly journals Flow and Turbulence Survey for a Model of Gas Turbine Exhaust Diffuser

1995 ◽  
Author(s):  
Umberto Desideri ◽  
Giampaolo Manfrida
Keyword(s):  
Gas Turbines ◽  
Suction Side ◽  
Stationary Flow ◽  
Scale Model ◽  
Medium Size ◽  
Hot Wire ◽  
Flow Measurements ◽  
Flow Angle ◽  
Probe Calibration ◽  
Hot Film

This paper presents the results of an extensive set of measurements on a model of an exhaust diffuser for gas turbines. The diffuser is of the straight-wall annular-axial type, typically employed in small-to-medium size gas turbines. It features six high-solidity struts, which support, in the real machine, one of the shaft bearings and have piping for oil supply inside. The 35%-scale model has been tested on a special test stand developed at the University of Perugia, using the suction side of a centrifugal-flow industrial fan of suitable capacity. Inlet speed is around 80 m/s, allowing satisfactory accuracy for flow measurements and the similarity in terms of Reynolds number. The instrumentation, the movement of the measurement point and data acquisition system were designed for automatic running of the tests. Both pneumatic and hot-wire or hot-film probes can be used on the same facility. The same wind tunnel, previous a quick replacement of the model with a probe calibration test section, can be used for calibration of both pneumatic and hot-wire/hot-film probes. A three hole directional pneumatic probe was used for stationary flow measurements to determine the global performance parameters of the model and a split-film probe was used to determine the turbulence characteristics. For four test sections, contour plots are produced of average velocity components, flow angle and turbulence quantities as three components of the Reynolds stress tensor.

scholarly journals Neural Network-Based System Identification for Quadcopter Dynamic Modeling: A Review

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Mohammad Fahmi Pairan ◽  
◽  
Syariful Syafiq Shamsudin ◽  
Mohd Fadhli Zulkafli ◽  
◽  
...  
Keyword(s):  
Neural Network ◽  
System Identification ◽  
Flight Dynamics ◽  
Governing Equations ◽  
Development Costs ◽  
Aerodynamic Database ◽  
Modeling Techniques ◽  
Comprehensive Survey ◽  
Identification Approach ◽  
The Mathematical Model

A quadcopter is a rotorcraft with a simple mechanical construction. It has the same hovering capability similar to the traditional helicopter, but it is easier to maintain. The quadcopter is hard to control due to its unstable system with highly coupled and non-linear dynamics. In order to design a robust control algorithm, it is crucial to obtain a precise quadrotor flight dynamics through system identification approach. System identification is a method of finding the mathematical model of the dynamics system using the input-output data measurement. Neural network (NN) based system identification is excellent alternative modeling because it reduces development costs and time by avoiding governing equations and large aerodynamic database. NN based system identification has successfully identified the quadcopter dynamics with good accuracy. This paper gives an overview of the characteristic of the quadcopter and presents a comprehensive survey of the modeling techniques used to determine the flight dynamics of a quadrotor with a particular focus on NN based system identification method. The presented research works have been classified into different categories such as the first principle modeling, system identification and implementation of NN based system identification in quadcopter platform. Finally, the paper highlights challenges that need to be addressed in developing efficient NN based system identification model for unmanned quadcopter system.

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