Design of a Multijet Omnidirectional Propulsion System for Small Jet-Boats

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
David Foley ◽  
Jean-Sebastien Plante
Keyword(s):  
High Speed ◽  
Flow Model ◽  
Open Loop ◽  
Propulsion System ◽  
Experimental Results ◽  
Control Algorithms ◽  
Control Laws ◽  
Low Speed ◽  
Advanced Control ◽  
Design Requirements

Jet-boats perform remarkably well at high-speed but lack low speed maneuverability for tight maneuvers such as docking. This paper presents a joystick controlled omnidirectional propulsion system for jet-boats. The concept uses a set of fixed jet nozzles disposed around the hull. When a force is commanded by the joystick, valves on each nozzle modulate the flow so that the sum of nozzle thrusts correspond to the commanded force. The positions and angles of the nozzles are optimized with an index of omnidirectionality quality based on the projection of a set of force solutions on a shell with the shape of a desired force space. The choice of valve positions and engine speeds is done by the numerical inversion of an internal viscous flow model. A 3D simulator, backed by experimental results, serves to (1) evaluate the ability of the proposed concept in meeting its design requirements and (2) develop control algorithms. Experimental results show that the proposed omnidirectional system is effective for low speed maneuverability with open-loop force control. The present work also offers an effective omnidirectional propulsion system that is easy to enhance with advanced control laws. Velocity feedback control is given as an example and shows important improvement of maneuverability and robustness to miscalibration.

Modeling and Parameter Identification of an In-Tank Swimming Robot Performing Floor Inspection

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Imen Hbiri ◽  
Houssem Karkri ◽  
Fathi H. Ghorbel ◽  
Slim Choura
Keyword(s):  
Dynamic Model ◽  
Drag Force ◽  
Equations Of Motion ◽  
Experimental Tests ◽  
Force Model ◽  
Friction Drag ◽  
Control Laws ◽  
Low Speed ◽  
Advanced Control ◽  
Computational Fluid Dynamics Cfd

In this paper, we develop the equations of motion at low-speed of a swimming robot for tank floor inspection. The proposed dynamic model incorporates a new friction drag force model for low-speed streamlined swimming robots. Based on a boundary layer theory analysis, we prove that for low-speed maneuvering case (Re from 103 to 105), the friction drag force component is nonlinear and is not insignificant, as previously considered. The proposed drag viscous model is derived based on hydrodynamic laws, validated via computational fluid dynamics (CFD) simulations, and then experimental tests. The model hydrodynamic coefficients are estimated through CFD tools. The robot wheels friction LuGre model is experimentally identified. Extensive experimental tests were conducted on the swimming robot in a circular water pool to validate the complete dynamic model. The dynamic model developed in this paper may be useful to design model-based advanced control laws required for accurate maneuverability of floor inspection swimming robots.

scholarly journals Modal Engineering for MEMS Devices: Application to Galvos and Scanners

2020 ◽  
Author(s):  
Lawrence Barrett ◽  
Matthias Imboden ◽  
Josh Javor ◽  
David K. Campbell ◽  
David J. Bishop
Keyword(s):  
High Speed ◽  
Open Loop ◽  
Optical Systems ◽  
Control Algorithms ◽  
Mems Devices ◽  
Open Loop Control ◽  
Optical Elements ◽  
Loop Control ◽  
High Q ◽  
Change Position

Optical systems typically use galvanometers (aka galvos) and scanners. Galvos move optical elements such as mirrors, quasi-statically, from one static position to another, and an important figure of merit is their step-settle relaxation time. Scanners move in an oscillatory fashion, typically at the device resonant frequency. MEMS devices, which have many advantages and are often used in such optical systems, are typically high Q devices. Moving from one position to another for a galvo or one frequency/amplitude to another for scanners, can take many periods to settle following the ring down. During these transitions, the optical system is inactive and the time is not being efficiently used. In this article we show how a novel class of open loop control algorithms can be used to rapidly change position, frequency and amplitude, typically in well under the period of the device. We show how the MEMS designer can excite, with complete, high-speed control, a vibrational mode of the system. We call this modal engineering, the ability to control the modes of the system in a practical, fast way. This control of the modes is accomplished with open loop control algorithms.

scholarly journals A 21st Century Warship With a 21st Century Propulsion System

1998 ◽  
Author(s):  
Mark Carter ◽  
Magnus Olsson ◽  
Jan-Erik Gustavson ◽  
Joe Ranero
Keyword(s):  
21St Century ◽  
Diesel Engines ◽  
High Speed ◽  
Propulsion System ◽  
Design Features ◽  
Signal Model ◽  
Turbine Engine ◽  
Low Speed

The Visby Class Corvette will enjoy the advantages of a Combined Diesel or Gas (CODOG) turbine arrangement in which the diesel engines are used for low-speed mine hunting and ASW missions, while the four turbines can be operated either individually or in pairs to provide cruise or high-speed dash capability. The integration of these features into a single gearbox, the design of the Allied Signal model TF50A turbine engine, and the integration of the CODOG system into the ship is discussed herein. Attention is focused on the unique design features which provide the “stealth” capabilities of this ship.

A Study on Velocity Decay of φ6mm Tungsten Ball Fragment

2014 ◽  
Vol 1042 ◽  
pp. 154-158
Author(s):  
Chun Lin Yi ◽  
De Ren Kong ◽  
Yi Zhao Li ◽  
Li Ping Li ◽  
Jin Qiu Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Least Square Method ◽  
Least Square ◽  
Experimental Results ◽  
Measuring System ◽  
Low Speed ◽  
Velocity Decay ◽  
Velocity Attenuation ◽  
Attenuation Models ◽  
Velocity Measuring

In order to explore the velocity attenuation law and model of φ6mm tungsten ball fragment, theory analysis combined with tests is employed to study its velocity experimental results. First of all, a fragment velocity measuring system including 12 groups of cutting device is established. Then the attenuation experiments of φ6mm tungsten ball fragment in high speed and low speed velocity are performed by the measuring system. Based on the least-square method, MATLAB software is adopted to analysis the experimental data and obtained the high speed and low speed velocity attenuation models. The results show that φ6mm tungsten ball fragment speed attenuation coefficient is consistent in high speed and low. Thus, the analysis on velocity experimental results verifies that the established model is reasonable.

Effect of Rotating Speed on Properties of Antireflective Coatings

2011 ◽  
Vol 181-182 ◽  
pp. 443-446
Author(s):  
Rui Min Jin ◽  
Xin Feng Guo ◽  
Zhi Duan Cai ◽  
Li Min Cang ◽  
Yan Tao ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
High Speed ◽  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Experimental Results ◽  
Antireflective Coatings ◽  
Low Speed ◽  
Rotating Speed ◽  
Coating Technique

Sol-gel thin films prepared by rotating coating technique, sol–gel derived bulk was prepared from constant water (H2O)/tetraethyl-orthosilicate (TEOS) ratio, rotating coating was carried out at different rotating speed 1000r/min (high speed) and 800r/min (low speed), 1500r/min (high speed) and 800r/min (low speed),2000r/min (high speed) and 800r/min (low speed),2500r/min (high speed) and 800r/min (low speed) respectively. The films were characterized by ellipsometer and SEM respectively. The experimental results show the thickness and refractive index of films are become smaller and smaller with the rotating speeds increasing.

An Advanced Control and Monitoring System for Turbomachinery

1995 ◽  
Author(s):  
Wilfried Blotenberg
Keyword(s):  
Monitoring System ◽  
High Speed ◽  
Data Logging ◽  
Control Laws ◽  
Advanced Control ◽  
Process Simulations ◽  
Compressor Surge ◽  
Surge Control ◽  
Dynamic Process Simulation ◽  
Control And Monitoring System

An advanced digital control and monitoring system for turbomachinery is introduced. Important aspects for the design of anti-surge control systems, such as the influence of the controller program execution time on the performance, are investigated. The influence of the gas composition (molecular weight) on the compressor surge line is demonstrated. Control laws are discussed. The design basis of an ultra-high speed anti-surge and speed control system is shown and the data-logging features are demonstrated on the log of a compressor surge. The paper closes describing some dynamic process simulation being performed using the controller hardware and software for process simulations.

Research on the Field Dynamic Balancing Technology and Instrument for a High Speed Cantilever Rotor

2014 ◽  
Vol 633-634 ◽  
pp. 1220-1228
Author(s):  
Zhi Xin Zhang ◽  
Yu Long Fu ◽  
Shi Zheng He ◽  
Ji Yong Kuang
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Dynamic Balancing ◽  
Signal Process ◽  
Low Speed ◽  
Full Speed ◽  
Field Dynamic ◽  
Field Dynamic Balancing

The principle of balancing a high speed cantilever rotor at full speed has been put forward by low-speed and high-speed balancing. The portable field dynamic balancing instrument based on the microcontroller is discussed from the hardware, the software and the signal process in detail. With the developed instrument, the whole-machine balancing experiment was conducted on a saucer-separating centrifuge RJ-460. The vibration of the saucer-separating centrifuge decreased from 3.8mm/s to 0.3mm/s at 1200r/min and decreased from 9.8mm/s to 0.6mm/s at 7200r/min. The experimental results indicated that the principle of balance is correct and the designed instrument is reliable and promising.

Propulsion System Design for the Multi-Mission Patrol Ship Mark 1/1A

1978 ◽  
Author(s):  
L. E. Bronson ◽  
R. M. Prentice
Keyword(s):  
System Design ◽  
Gas Turbines ◽  
High Speed ◽  
Propulsion System ◽  
Two Stage ◽  
Low Speed ◽  
Made In

PSMM Mkl/1A is a high-speed patrol ship designed to accomplish a variety of missions. It is a 165-ft aluminum hull powered by six gas turbines driving two controllable reversible pitch propellers. Two-stage combining reduction gears with self-synchronizing clutches enable the ship to operate at speeds to 40 knots on from one to six turbines. Controllable pitch propellers are used to optimize operations in high- or low-speed maneuvers. The propulsion system is controlled by a pair of analog computers which automatically select shaft rpm and propellers pitch based on power command and the number of turbines operating. This paper will discuss the propulsion system and controls as designed, the modifications made during trials of the Mk1 in late 1974, and the improvements made in the Mk 1A and proved during trials in 1977.

A Solid-State On-Load Tap Changer for the Power Transformers of 10—0.4 kV Distribution Networks

Vestnik MEI ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 82-90
Author(s):  
Dmitriy I. Panfilov ◽  
◽  
Mikhail G. Astashev ◽  
Aleksandr V. Gorchakov ◽  
◽  
...  
Keyword(s):  
Solid State ◽  
Physical Model ◽  
High Speed ◽  
Power Transformer ◽  
Voltage Control ◽  
Power Transformers ◽  
Control Algorithms ◽  
Load Voltage ◽  
Tap Changer ◽  
Load Tap Changer

The specific features relating to voltage control of power transformers at distribution network transformer substations are considered. An approach to implementing high-speed on-load voltage control of serially produced 10/0.4 kV power transformers by using a solid-state on-load tap changer (SOLTC) is presented. An example of the SOLTC circuit solution on the basis of thyristor switches is given. On-load voltage control algorithms for power transformers equipped with SOLTC that ensure high reliability and high-speed operation are proposed. The SOLTC performance and the operability of the suggested voltage control algorithms were studied by simulation in the Matlab/Simulink environment and by experiments on the SOLTC physical model. The structure and peculiarities of the used simulation Matlab model are described. The SOLTC physical model design and its parameters are presented. The results obtained from the simulating the SOLTC operation on the Matlab model and from the experiments on the SOLTS physical model jointly with a power transformer under different loads and with using different control algorithms are given. An analysis of the experimental study results has shown the soundness of the adopted technical solutions. It has been demonstrated that the use of an SOLTC ensures high-speed voltage control, high efficiency and reliability of its operation, and arcless switching of the power transformer regulating taps without load voltage and current interruption. By using the SOLTC operation algorithms it is possible to perform individual phase voltage regulation in a three-phase 0.4 kV distribution network. The possibility of integrating SOLTC control and diagnostic facilities into the structure of modern digital substations based on the digital interface according to the IEC 61850 standard is noted.

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