52 research outputs found
Application of MPC and sliding mode control to IFAC benchmark models
The comparison of Model Predictive Control (MPC) and Sliding Mode Control (SMC) are
presented in this paper. This paper investigates the performance of each controller as the navigation system
for IFAC benchmark ship models (cargo vessel and oil tanker). In this investigation the navigation system
regulates the heading angle of the two types of marine vessel with reference to a desired heading
trajectory. In this investigation, the result obtained from MPC is compared with a well-established control
methodology, namely Sliding Mode control theory. Wave disturbances and actuator limits are
implemented to provide a more realistic evaluation and comparison for the proposed control structure
Modelling and simulation of a biomimetic underwater vehicle
This paper describes work carried out at the
University of Glasgow investigating biomimetic
fish-like propulsion systems for underwater
vehicles. The development of a simple
mathematical model is described for a
biomimetic fish like vehicle which utilizes a
tendon drive propulsion system. This model is
then compared with a model of a vehicle of
similar size but with a propeller for main
propulsion. Simulation results for both models
are shown and compared
Applications of inverse simulation to a nonlinear model of an underwater vehicle
Inverse simulation provides an important alternative
to conventional simulation and to more formal
mathematical techniques of model inversion. The
application of inverse simulation methods to a nonlinear
dynamic model of an unmanned underwater vehicle with
actuator limits is found to give rise to a number of
challenging problems. It is shown that this particular
problem requires, in common with other applications that
include hard nonlinearities in the model or discontinuities
in the required trajectory, can best be approached using a
search-based optimization algorithm for inverse
simulation in place of the more conventional Newton-
Raphson approach. Results show that meaningful inverse
simulation results can be obtained but that multi-solution
responses exist. Although the inverse solutions are not
unique they are shown to generate the required
trajectories when tested using conventional forward
simulation methods
Optimisation of the weighting functions of an H<sub>∞</sub> controller using genetic algorithms and structured genetic algorithms
In this paper the optimisation of the weighting functions for an H<sub>∞</sub> controller using genetic algorithms and structured genetic algorithms is considered. The choice of the weighting functions is one of the key steps in the design of an H<sub>∞</sub> controller. The performance of the controller depends on these weighting functions since poorly chosen weighting functions will provide a poor controller. One approach that can solve this problem is the use of evolutionary techniques to tune the weighting parameters. The paper presents the improved performance of structured genetic algorithms over conventional genetic algorithms and how this technique can assist with the identification of appropriate weighting functions' orders
Genetic programming for the automatic design of controllers for a surface ship
In this paper, the implementation of genetic programming (GP) to design a contoller structure is assessed. GP is used to evolve control strategies that, given the current and desired state of the propulsion and heading dynamics of a supply ship as inputs, generate the command forces required to maneuver the ship. The controllers created using GP are evaluated through computer simulations and real maneuverability tests in a laboratory water basin facility. The robustness of each controller is analyzed through the simulation of environmental disturbances. In addition, GP runs in the presence of disturbances are carried out so that the different controllers obtained can be compared. The particular vessel used in this paper is a scale model of a supply ship called CyberShip II. The results obtained illustrate the benefits of using GP for the automatic design of propulsion and navigation controllers for surface ships
Sliding Mode Implementation of an Attitude Command Flight Control System for a Helicopter in Hover
This paper presents an investigation into the design of a flight control system, using a decoupled non-linear sliding mode control structure, designed using a linearised, 9th order representation of the dynamics of a PUMA helicopter in hover. The controllers are then tested upon a higher order, non-linear helicopter model, called RASCAL. This design approach is used for attitude command flight control implementation and the control performance is assessed in the terms of handling qualities through the Aeronautical Design Standards for Rotorcraft (ADS-33). In this context a linearised approximation of the helicopter system is used to design an SMC control scheme. These controllers have been found to yield a system that satisfies the Level 1 handling qualities set out by ADS-33.
The diffusion of sustainability and Dingle Peninsula 2030
Instilling a collaborative approach can widen participation to a range of stakeholders, enabling the diffusion of sustainability and increasing local capacity to meet decarbonisation targets to mitigate against climate change. Dingle Peninsula 2030 has emerged as an international case study of a collaborative regional sustainability project, whereby a wide range of initiatives, beyond the initial remit of the project, have emerged in the area. This holistic scale of action is required for effective climate action. Using the Sustainable Development Goals (SDGs) as a framing, the interrelated nature of climate action has been shown through this study. In setting out to undergo energy projects a wide range of new initiatives emerged as community members became engaged in the process. Initiatives have emerged related to energy, transport, agriculture, education, tourism and employment, in what we have coined the ‘diffusion of sustainability’
Understanding how institutions may support the development of transdisciplinary approaches to sustainability research
This article analyses the approaches of academics seeking to engage with private, public and community-based stakeholders through transdisciplinary research about pressing sustainability challenges and, in particular, climate change; it outlines aspects of the institutional factors which influence transdisciplinary research. A qualitative approach was employed in conducting 10 semi-structured interviews to analyse the challenges and motivations of academic researchers when working with a range of other stakeholders through transdisciplinary practice. Two key contributions are made through this work. First, this article adds to the existing literature on motivations and challenges for undertaking research with private, public and community stakeholders in a cross-disciplinary manner. Second, the current institutional circumstances influencing such research practices are outlined, alongside potential ways forward. The research presented here has been undertaken in light of the experiences of the two lead co-authors as early career researchers coming from the disciplines of sociology and energy engineering, engaging in transdisciplinary research within a local community context in relation to a regional energy transition project
Understanding concurrent earcons: applying auditory scene analysis principles to concurrent earcon recognition
Two investigations into the identification of concurrently presented, structured sounds, called earcons were carried out. One of the experiments investigated how varying the number of concurrently presented earcons affected their identification. It was found that varying the number had a significant effect on the proportion of earcons identified. Reducing the number of concurrently presented earcons lead to a general increase in the proportion of presented earcons successfully identified. The second experiment investigated how modifying the earcons and their presentation, using techniques influenced by auditory scene analysis, affected earcon identification. It was found that both modifying the earcons such that each was presented with a unique timbre, and altering their presentation such that there was a 300 ms onset-to-onset time delay between each earcon were found to significantly increase identification. Guidelines were drawn from this work to assist future interface designers when incorporating concurrently presented earcons
Paul G. Leahy, Connor McGookin, Hannah E. Daly
In 2020, the Energy Engineering programme team at University College Cork undertook a redesign of the introductory first-year module in Energy Engineering. The aim was to introduce a more experientially-based learning experience and to allow first-year students greater opportunity to develop and demonstrate performance-based understanding. The key material change to the module was to incorporate design and group work in the first year of the programme. In the Wind Turbine Maker Challenge, groups of 4-5 students were tasked with designing and building a working wind turbine. Students were provided with kits comprising some basic elements of turbines including small generators and gearboxes and simple, flat blades. However, the focus of the exercise was on original design, particularly of the aerodynamic rotor components of the turbines. The participants had to source their own materials for the wind turbine rotors, and were encouraged to use recovered or recycled materials. Students were also asked to consider ethical aspects of wind energy generation. In developing this approach, the conceptualisation of teaching as setting up and facilitating students' performance was to the forefront. The formal classroom instruction was limited to only the core knowledge required to enable students to begin to consider suitable materials, geometries for their turbine designs through hands-on experimentation. Survey feedback from students showed that they had strongly focussed on the environmental and sustainability aspects of the exercise. Students were asked what they thought the goal of the exercise was. Students’ reported understandings of the main goal varied widely, for example “Learning how wind turbines work” and “Working as a team towards a common goal”. However, all of the students’ reported goals were compatible with the module’s learning outcomes
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