EWST (Edinburgh Wave Systems Toolbox)

The EWST (Edinburgh Wave Systems Toolbox) is a suite of tools for the simulation of wave energy devices. EWST has the ability to model devices that are comprised of rigid bodies, power-take-off systems, and mooring systems. Simulations are performed in the time-domain by solving the governing WEC equations of motion in 6 degrees-of-freedom.

EWST is derived from WEC-Sim, an open-source wave energy converter simulation tool developed in Matlab/Simulink using the multi-body dynamics solver Simscape Multibody. The EWST is also developed in Matlab, but drops the requirement for Simulink or Simscape Multibody. It also aims to be compatible with Octave, an alternative system able to process much of the standard Matlab code base. The hydrodynamic data format for both is identical, so hydrodynamic data can be easily ported between systems.

EWST replaces the mutlibody modelling parts of the code with MBDyn, an advanced multiboy dynamics simulator. An advanced Matlab code based MBDyn preprocessor is available to allow the creation of MBDyn model input files directly from Matlab. Detailed documentation of the preprocesing tool may be found in it’s own dedicated manual.

Purpose

With the existance of Wec-Sim the need for EWST may nt be obvious. EWST addresses several main perceived issues with Wec-Sim.

1. Maintainability: Wec-Sim being heavily based in Simulink does not lend itself to maintenance using standard software version control systems (e.g. Git, Mercurial). Simulink files cannot be easily compared for changes using these systems.

2. Debugability: Debugging a purely code based system is easier than one based in Simulink, as the ability to step through the code and navigate the different levels of the system is more advanced. purely code-based

3. Interface design: The developers of EWST have a different interface design philosophy which is more conventional than the WEC-Sim method. The EWST interface is more oriented toward automation and batch processing than the original WEC-Sim interface. This is mainly to facilitate randomised simulation and optimisation algorithms.

4. Modifiability: Being purely code based, and with all code in one location (rather than spread throughout Simulink models)

5. Cost: WEC-Sim requires many commercial platforms to be operated, EWST can be run entirely on free software (although the performance on Matlab will be superior).

The EWST developers recognise that not everyone will agree with the points above or that they justify the creation of a separate system, but it was these needs which drove it’s creation.

An aim of the project will continue to be to maintain compatibility as much as possible between the two systems

Developers and Contributers

The Edinburgh Wave Systems Toolbox has been created by The Institute for Energy Systems at The University of Edinburgh as part of the EPSRC funded project “All Electrical Drive Train for Marine Energy Converters (EDRIVE-MEC)”, grant No. EP/N021452/1. The main contributor is Dr. Richard Crozier.

Contents:

• EWST (Edinburgh Wave Systems Toolbox)
• Installation
  • RenewNet Foundry
  • Nemoh
• Getting Started
  • Code and Data Organisation
  • Example: The RM3 Two Body Point Absorber
  • Generating Hydrodynamic Data
  • System Simulation
  • Conclusions
• Required Knowledge
  • Parameter-Value Pairs
  • The Matlab Path
  • Namespaces (+package directories)
  • Classes (classdef)
  • The Matlab Help System
• NEMOH
  • Getting Nemoh
  • NEMOH Preprocessor
  • The NEMOH Executables Location
• API Reference
  • wsim.exportBodyHydroDataToCSV
  • Class: wsim.hydroBody
  • Class: wsim.hydroSystem
  • Class: wsim.linearPMMachinePTO
  • Class: wsim.linearPTOWithController
  • Class: wsim.linearPowerTakeOff
  • Class: wsim.logger
  • Class: wsim.loggingSettings
  • Class: wsim.powerTakeOff
  • Class: wsim.rotaryPowerTakeOff
  • Class: wsim.simSettings
  • wsim.stackedForcePlot
  • Class: wsim.waveSettings
  • Class: wsim.wecController
  • Class: wsim.wecControllerFcnBased
  • Class: wsim.wecSim

Indices and tables

• Index
• Module Index
• Search Page