scholarly journals Control-Influenced Layout Optimization of Arrays of Wave Energy Converters

2014 ◽  
Author(s):  
Philip Balitsky ◽  
Giorgio Bacelli ◽  
John V. Ringwood
Keyword(s):  
Wave Climate ◽  
Radiative Properties ◽  
Optimal Layout ◽  
Wave Direction ◽  
Sea State ◽  
Wave Energy Converters ◽  
Control Schemes ◽  
And Control ◽  
Tuning Scheme ◽  
Optimal Configurations

In this paper we compare the optimal configurations for an array of WECs given two control schemes, a real-time global control and a passive sea-state based tuning scheme. In a particular wave climate and array orientation with its axis normal to the prevailing wave direction, closely-spaced symmetrical arrays of 2, 3, 4, 5, and 6 cylinders of different radiative properties are simulated for varying inter-device separation distances. For each device and control type, we focus on the factors that influence the optimal layout, including number of devices, separating distance and angular spreading. The average annual power output is calculated for each optimal configuration.

Fatigue Load Reductions in Offshore Wind Turbine Monopile Foundations in Co-Located Wind-Wave Arrays

2018 ◽  
Author(s):  
Caitlyn E. Clark ◽  
Joey Velarde ◽  
Jannie Sønderkær Nielsen
Keyword(s):  
Wave Climate ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Loads ◽  
Fatigue Load ◽  
Limit States ◽  
Sea State ◽  
Total Load ◽  
Offshore Wind Turbines ◽  
Wave Energy Converters

As offshore wind turbines (OWTs) increase in size and are placed farther offshore, hydrodynamic loads have increased contribution to total load, resulting in fatigue limit states becoming more important to consider in structural design. Previous literature shows that placing wave energy converters (WECs) peripherally to an OWT array results in a milder wave climate within the array. This reduction could affect the wave loads and fatigue damage of OWT support structures. In this exploratory study, the effect of peripherally-distributing WECs in front of a fixed-bottom OWT on the fatigue of the OWT monopile is investigated. Relative sea state reductions from WECs are quantified, and fully-coupled time-domain fatigue analyses are performed for a 10 MW reference OWT. Results indicate that both a single WEC and a WEC array can lead to up to 8% and 10% fatigue load reduction in unidirectional wave cases, respectively.

Experimental Assessment of the IFPEN Solution to the WEC Control Competition

2020 ◽  
Author(s):  
Paolino Tona ◽  
Guillaume Sabiron ◽  
Hoai-Nam Nguyen ◽  
Alexis Mérigaud ◽  
Caroline Ngo
Keyword(s):  
Electrical Energy ◽  
Irregular Waves ◽  
Sea State ◽  
Experimental Assessment ◽  
Wave Energy Converters ◽  
Tank Test ◽  
Short Term Prediction ◽  
And Control ◽  
Experimental Stage ◽  
Wave Excitation Force

Abstract This paper describes the experimental assessment of the solution developed by IFP Energies nouvelles (IFPEN) for the WEC Control Competition (WECCCOMP), a benchmark devised to compare energy-maximizing controllers for wave energy converters (WECs). For the first round of the competition, carried out in simulation with WEC-Sim, IFPEN had submitted an MPC-based solution, which eventually scored best among the contestants, with respect to the energy-related criterion defined by the organizers and computed on a set of six irregular waves. For the second round of the competition, the performance of this MPC solution has been assessed in a tank test situation, on the same Wavestar-like scale device that had been simulated in WEC-Sim. The paper first recalls the features of the control solution implemented for the competition, an offline-tuned weighted-QP MPC algorithm using short-term prediction from present and past wave excitation force estimates. Then, the major steps of the test plan are described and control design choices are explained. Finally, the experimental results in closed loop are presented. Despite noise and an imperfectly controlled PTO actuator, IFPEN’s MPC solution proves efficient and robust: its experimental performance in terms of harvested electrical energy is in accordance with the nominal results obtained in simulation using the linear design model, and this, for different realizations of each sea state. This performance has allowed the IFPEN team to win the competition also at the experimental stage.

Biohybrid robots are synthetic biology systems

2018 ◽  
Author(s):  
Joseph Ayers
Keyword(s):  
Nervous System ◽  
Synthetic Biology ◽  
Behavioral Control ◽  
Eukaryotic Cells ◽  
Chemical Senses ◽  
Biomimetic Robots ◽  
Control Schemes ◽  
Induced Pluripotent ◽  
And Control ◽  
And Robotics

This chapter describes how synthetic biology and organic electronics can integrate neurobiology and robotics to form a basis for biohybrid robots and synthetic neuroethology. Biomimetic robots capture the performance advantages of animal models by mimicking the behavioral control schemes evolved in nature, based on modularized devices that capture the biomechanics and control principles of the nervous system. However, current robots are blind to chemical senses, difficult to miniaturize, and require chemical batteries. These obstacles can be overcome by integration of living engineered cells. Synthetic biology seeks to build devices and systems from fungible gene parts (gene systems coding different proteins) integrated into a chassis (induced pluripotent eukaryotic cells, yeast, or bacteria) to produce devices with properties not found in nature. Biohybrid robots are examples of such systems (interacting sets of devices). A nascent literature describes genes that can mediate organ levels of organization. Such capabilities, applied to biohybrid systems, portend truly biological robots guided, controlled, and actuated solely by life processes.

scholarly journals Vertical Jumping for Legged Robot Based on Quadratic Programming

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3679
Author(s):  
Dingkui Tian ◽  
Junyao Gao ◽  
Xuanyang Shi ◽  
Yizhou Lu ◽  
Chuzhao Liu
Keyword(s):  
Quadratic Programming ◽  
Stance Phase ◽  
Center Of Mass ◽  
Maximum Error ◽  
Legged Robot ◽  
Flight Phase ◽  
Programming Framework ◽  
Vertical Jumping ◽  
Control Schemes ◽  
And Control

The highly dynamic legged jumping motion is a challenging research topic because of the lack of established control schemes that handle over-constrained control objectives well in the stance phase, which are coupled and affect each other, and control robot’s posture in the flight phase, in which the robot is underactuated owing to the foot leaving the ground. This paper introduces an approach of realizing the cyclic vertical jumping motion of a planar simplified legged robot that formulates the jump problem within a quadratic-programming (QP)-based framework. Unlike prior works, which have added different weights in front of control tasks to express the relative hierarchy of tasks, in our framework, the hierarchical quadratic programming (HQP) control strategy is used to guarantee the strict prioritization of the center of mass (CoM) in the stance phase while split dynamic equations are incorporated into the unified quadratic-programming framework to restrict the robot’s posture to be near a desired constant value in the flight phase. The controller is tested in two simulation environments with and without the flight phase controller, the results validate the flight phase controller, with the HQP controller having a maximum error of the CoM in the x direction and y direction of 0.47 and 0.82 cm and thus enabling the strict prioritization of the CoM.

scholarly journals Joint Modelling of Wave Energy Flux and Wave Direction

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 460
Author(s):  
Takvor H. Soukissian ◽  
Flora E. Karathanasi
Keyword(s):  
Energy Flux ◽  
Wave Energy ◽  
Goodness Of Fit ◽  
North Atlantic Ocean ◽  
Wave Climate ◽  
Western Mediterranean ◽  
Wave Direction ◽  
Bivariate Model ◽  
The North ◽  
Wave Energy Flux

In the context of wave resource assessment, the description of wave climate is usually confined to significant wave height and energy period. However, the accurate joint description of both linear and directional wave energy characteristics is essential for the proper and detailed optimization of wave energy converters. In this work, the joint probabilistic description of wave energy flux and wave direction is performed and evaluated. Parametric univariate models are implemented for the description of wave energy flux and wave direction. For wave energy flux, conventional, and mixture distributions are examined while for wave direction proven and efficient finite mixtures of von Mises distributions are used. The bivariate modelling is based on the implementation of the Johnson–Wehrly model. The examined models are applied on long-term measured wave data at three offshore locations in Greece and hindcast numerical wave model data at three locations in the western Mediterranean, the North Sea, and the North Atlantic Ocean. A global criterion that combines five individual goodness-of-fit criteria into a single expression is used to evaluate the performance of bivariate models. From the optimum bivariate model, the expected wave energy flux as function of wave direction and the distribution of wave energy flux for the mean and most probable wave directions are also obtained.

scholarly journals On the generation of validated manufacturing process optimization and control schemes

Procedia CIRP ◽  
2021 ◽  
Vol 96 ◽  
pp. 57-62
Author(s):  
Alexios Papacharalampopoulos ◽  
Harry Bikas ◽  
Christos Michail ◽  
Panagiotis Stavropoulos
Keyword(s):  
Process Optimization ◽  
Manufacturing Process ◽  
Control Schemes ◽  
Optimization And Control ◽  
And Control

scholarly journals Optimizing the Power Take Off of a Wave Energy Converter With Regard to the Wave Climate

2005 ◽  
Vol 128 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Gaelle Duclos ◽  
Aurelien Babarit ◽  
Alain H. Clément
Keyword(s):  
Wave Energy ◽  
Simple Wave ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Optimal Parameters ◽  
Energy Converter ◽  
Wave Energy Converters ◽  
Classical Wave ◽  
Project Site ◽  
Wave Conditions

Considered as a source of renewable energy, wave is a resource featuring high variability at all time scales. Furthermore wave climate also changes significantly from place to place. Wave energy converters are very often tuned to suit the more frequent significant wave period at the project site. In this paper we show that optimizing the device necessitates accounting for all possible wave conditions weighted by their annual occurrence frequency, as generally given by the classical wave climate scatter diagrams. A generic and very simple wave energy converter is considered here. It is shown how the optimal parameters can be different considering whether all wave conditions are accounted for or not, whether the device is controlled or not, whether the productive motion is limited or not. We also show how they depend on the area where the device is to be deployed, by applying the same method to three sites with very different wave climate.

Design, Construction and Control of a Remotely Operated Vehicle (ROV)

2011 ◽  
Author(s):  
Alireza Marzbanrad ◽  
Jalil Sharafi ◽  
Mohammad Eghtesad ◽  
Reza Kamali
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Remotely Operated Vehicle ◽  
Six Degrees Of Freedom ◽  
Depth Sensors ◽  
Control Schemes ◽  
On Line ◽  
Operation Unit ◽  
And Control ◽  
Design Construction

This is report of design, construction and control of “Ariana-I”, an Underwater Remotely Operated Vehicle (ROV), built in Shiraz University Robotic Lab. This ROV is equipped with roll, pitch, heading, and depth sensors which provide sufficient feedback signals to give the system six degrees-of-freedom actuation. Although its center of gravity and center of buoyancy are positioned in such a way that Ariana-I ROV is self-stabilized, but the combinations of sensors and speed controlled drivers provide more stability of the system without the operator involvement. Video vision is provided for the system with Ethernet link to the operation unit. Control commands and sensor feedbacks are transferred on RS485 bus; video signal, water leakage alarm, and battery charging wires are provided on the same multi-core cable. While simple PI controllers would improve the pitch and roll stability of the system, various control schemes can be applied for heading to track different paths. The net weight of ROV out of water is about 130kg with frame dimensions of 130×100×65cm. Ariana-I ROV is designed such that it is possible to be equipped with different tools such as mechanical arms, thanks to microprocessor based control system provided with two directional high speed communication cables for on line vision and operation unit.

scholarly journals Numerical Investigation of Hydrodynamics and Cohesive Sediment Transport in Cua Lo and Cua Hoi Estuaries, Vietnam

2021 ◽  
Vol 9 (11) ◽  
pp. 1258
Author(s):  
Viet Thanh Nguyen ◽  
Minh Tuan Vu ◽  
Chi Zhang
Keyword(s):  
Sediment Transport ◽  
Great Influence ◽  
Wave Model ◽  
Sediment Concentration ◽  
Wave Climate ◽  
Cohesive Sediment ◽  
Wave Direction ◽  
The South ◽  
The North ◽  
Cohesive Sediment Transport

Two-dimensional models of large spatial domain including Cua Lo and Cua Hoi estuaries in Nghe An province, Vietnam, were established, calibrated, and verified with the observed data of tidal level, wave height, wave period, wave direction, and suspended sediment concentration. The model was then applied to investigate the hydrodynamics, cohesive sediment transport, and the morphodynamics feedbacks between two estuaries. Results reveal opposite patterns of nearshore currents affected by monsoons, which flow from the north to the south during the northeast (NE) monsoon and from the south to the north during the southeast (SE) monsoon. The spectral wave model results indicate that wave climate is the main control of the sediment transport in the study area. In the NE monsoon, sediment from Cua Lo port transported to the south generates the sand bar in the northern bank of the Cua Hoi estuary, while sediment from Cua Hoi cannot be carried to the Cua Lo estuary due to the presence of Hon Ngu Island and Lan Chau headland. As a result, the longshore sediment transport from the Cua Hoi estuary to the Cua Lo estuary is reduced and interrupted. The growth and degradation of the sand bars at the Cua Hoi estuary have a great influence on the stability of the navigation channel to Ben Thuy port as well as flood drainage of Lam River.

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