Path Planning and Open-Loop Control Algorithms for a Differential Thrust Autonomous Underwater Vehicle

Abstract The dynamic model and motion simulation for a Triangular-Shaped Autonomous Underwater Vehicle (TAUV) with independently controlled rudders are described in this paper. The TAUV is designed for biofouling cleaning in aquaculture cage fishnet. It is buoyant underwater and moves by controlling two thrusters. Hence, in this research work, the authors designed a TAUV that is propelled by two thrusters and maneuvered by using an independently controllable rudder. This paper discussed the development of a mathematical model for the TAUV and its dynamic characteristics. The mathematical model was simulated by using Matlab and Simulink to analyze the TAUV’s motion based on open-loop control of different rudder angles. The position, linear and angular velocities, angle of attack, and underwater vehicle speed are all demonstrated in the findings.

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Yield Improvement via minimization of step height non-uniformity in Chemical Mechanical Planarization (CMP)

MRS Proceedings ◽

10.1557/proc-867-w5.2 ◽

2005 ◽

Vol 867 ◽

Author(s):

Muthukkumar Kadavasal ◽

Sutee Eamkajornsiri ◽

Abhijit Chandra ◽

Ashraf F. Bastawros

Keyword(s):

Chemical Mechanical Planarization ◽

Open Loop ◽

Step Height ◽

Control Algorithms ◽

Open Loop Control ◽

Time Step ◽

Surface Evolution ◽

Loop Control ◽

Final Surface ◽

Pattern Density

AbstractObtaining local and global planarity is one of the prime criteria in dielectric and metal planarizations. Although Chemical Mechanical Planarization (CMP) helps us achieve this criterion in constant pattern density surfaces, the same is not true for variable pattern density surfaces this results in formation of global step heights across the die. This paper provides a pressure open loop control algorithms for obtaining planarity across a die containing variations in pattern densities. Based on the variation of pattern density and surface heights across the die, the surfaces are separated into zones and the pressure is varied spatially and/or temporally to obtain uniform surface heights, with enhanced step height uniformity. One of the algorithms looks ahead and recalculates/modifies the pressure values by identifying the step heights that could be formed after a specified time step. The final surface predictions have improved uniformity on the upper surface as well as on the step heights across the entire die. The simulation would help us track the polishing process for each time step and guide us with the optimized pressure values that can be applied in order to an uniform final surface evolution.

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Modal Engineering for MEMS Devices: Application to Galvos and Scanners

10.31224/osf.io/n53fx ◽

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.

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Design and Testing of a Spherical Autonomous Underwater Vehicle for Shipwreck Interior Exploration

Journal of Marine Science and Engineering ◽

10.3390/jmse9030320 ◽

2021 ◽

Vol 9 (3) ◽

pp. 320 ◽

Cited By ~ 1

Author(s):

Ross Eldred ◽

Johnathan Lussier ◽

Anthony Pollman

Keyword(s):

Degrees Of Freedom ◽

Autonomous Underwater Vehicle ◽

Open Water ◽

Underwater Vehicle ◽

Open Loop ◽

Loop Control ◽

Design Attributes ◽

System Requirements ◽

Design And Testing ◽

4 Degrees Of Freedom

This article details the design, construction and implementation of a novel, spherical unmanned underwater vehicle (UUV) prototype for operations within confined, entanglement-prone marine environments. The nature of shipwreck interiors, the exploration of which the vehicle was originally designed, imposes special risks that constrain system requirements while promoting other attributes uncommon in typical open-water UUV designs. The invention, the Wreck Interior Exploration Vehicle (WIEVLE), was constructed using 3-D additive manufacturing technology combined with relatively inexpensive commercial components. Similar inventions are compared, followed by a thorough review of the physical and functional characteristics of the system. The key attributes of the design include a smooth, spherical hull with 360-degree sensor coverage, and a fixed, upward-angled thruster core, relying on inherent buoyancy to take the place of a dedicated depth-changing mechanism. Initial open-loop control testing demonstrated stable 4 degrees of freedom (DOF) maneuvering capability. The article concludes with an overview of the results of the initial testing, a review of how the key system design attributes address the unique shipwreck interior exploration challenges, and a plan for the future development of the platform.

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Modal Engineering of Inductive Circuits to Achieve Rapid Settling Times

10.31224/osf.io/bd4zr ◽

2021 ◽

Author(s):

Josh Javor ◽

Lawrence Barrett ◽

Matthias Imboden ◽

Russ Giannetta ◽

David K. Campbell ◽

...

Keyword(s):

Magnetic Fields ◽

Open Loop ◽

Hall Sensor ◽

Control Algorithms ◽

Rf Coils ◽

Design Element ◽

Open Loop Control ◽

Modeling Tools ◽

Loop Control ◽

Important Design

Inductive circuits and devices are a ubiquitous and important design element in many applications such as magnetic drives, galvanometers, magnetic scanners, applying DC magnetic fields to systems, RF coils in NMR systems and vast array of other applications. They are widely used to generate both DC and AC magnetic fields. Many of these applications require a rapid step and settling time, turning the DC or AC magnetic field on and off quickly. The inductive response normally makes this a challenging thing to do. In this article we discuss open loop control algorithms for achieving rapid step and settling times in four general categories of applications: DC and AC systems where the system is either under or over damped. Each of these four categories requires a different algorithm which we describe here. We show the operation of these drive methods using Simulink and Simscape modeling tools, analytical solutions to the underlying differential equations and in experimental results using an inductive magnetic coil and a Hall sensor. Finally, we demonstrate application of these techniques to significantly reduce ringing in a standard NMR circuit. We intend this article to be practical with useful, easy to apply algorithms and helpful tuning tricks.

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Optimal Control of Nonlinear Structures

Journal of Applied Mechanics ◽

10.1115/1.3173744 ◽

1988 ◽

Vol 55 (4) ◽

pp. 931-938 ◽

Cited By ~ 47

Author(s):

J. N. Yang ◽

F. X. Long ◽

D. Wong

Keyword(s):

Optimal Control ◽

Control Systems ◽

Active Control ◽

Control Algorithm ◽

Open Loop ◽

Control Algorithms ◽

Nonlinear Structures ◽

Open Loop Control ◽

Loop Control ◽

Optimal Control Algorithms

Three optimal control algorithms are proposed for reducing oscillations of flexible nonlinear structures subjected to general stochastic dynamic loads, such as earthquakes, waves, winds, etc. The optimal control forces are determined analytically by minimizing a time-dependent quadratic performance index, and nonlinear equations of motion are solved using the Wilson-θ numerical procedures. The optimal control algorithms developed for applications to nonlinear structures are referred to as the instantaneous optimal control algorithms, including the instantaneous optimal open-loop control algorithm, instantaneous optimal closed-loop control algorithm, and instantaneous optimal closed-open-loop control algorithm. These optimal algorithms are computationally efficient and suitable for on-line implementation of active control systems to realistic nonlinear structures. Numerical examples are worked out to demonstrate the applications of these optimal control algorithms to nonlinear structures. In particular, control of structures undergoing inelastic deformations under strong earthquake excitations are illustrated. The advantage of using combined passive/active control systems is also demonstrated.

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