DEVELOPMENT OF NEW NONLINEAR CONTROLLERS FOR TRAJECTORY TRACKING AND PATH-FOLLOWING OF UNDERACTUATED OCEAN VEHICLES. Trajectory tracking control and path-following of underactuated ocean vehicles are not only of theoretical challenging but also important practice. This project is firstly to develop methodologies to design full-state feedback controllers to force the underactuated ocean vehicles including surface ships and underwater vehicles with off-diagonal terms in their system matrices to tr ....DEVELOPMENT OF NEW NONLINEAR CONTROLLERS FOR TRAJECTORY TRACKING AND PATH-FOLLOWING OF UNDERACTUATED OCEAN VEHICLES. Trajectory tracking control and path-following of underactuated ocean vehicles are not only of theoretical challenging but also important practice. This project is firstly to develop methodologies to design full-state feedback controllers to force the underactuated ocean vehicles including surface ships and underwater vehicles with off-diagonal terms in their system matrices to track reference trajectories generated by virtual vehicles, and to follow a predefined path with a desired forward speed. Secondly, we develop methods to design observers to estimate the unmeasured states (velocities) of the vehicles and incorporate with the full-state feedback controllers to have output-feedback observer-based controllers. Lastly, the proposed control design methods are extended to a certain class of underactuated mechanical systems.Read moreRead less
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0239920
Funder
Australian Research Council
Funding Amount
$195,000.00
Summary
Control of free/dissolved gas content in a cavitation tunnel. The proposed equipment is for increased productivity and enhancing research capability of the Tom Fink Cavitation Tunnel located at the Australian Maritime College.
The cavitation tunnel is used for investigating flows about ships and underwater bodies.
The proposed equipment permits the rapid control of gas content in the tunnel water either dissolved or free as bubbles which together control the nature of cavitation and other ....Control of free/dissolved gas content in a cavitation tunnel. The proposed equipment is for increased productivity and enhancing research capability of the Tom Fink Cavitation Tunnel located at the Australian Maritime College.
The cavitation tunnel is used for investigating flows about ships and underwater bodies.
The proposed equipment permits the rapid control of gas content in the tunnel water either dissolved or free as bubbles which together control the nature of cavitation and other two phase flows.
The equipment will significant enhance existing research programs in support of the high speed craft and defence sectors of the maritime industry both nationally and internationally.Read moreRead less
Deterioration of structural integrity of ageing ships and marine platforms. Deterioration of structural integrity of ageing ships and marine platforms. This project will research the deterioration of structural integrity and remaining life of marine assets such as ships and offshore energy facilities, by integrating structural response analysis methods with aged-structure assessment techniques. Maritime assets exposed to ocean conditions suffer from time dependent phenomena, which reduce structu ....Deterioration of structural integrity of ageing ships and marine platforms. Deterioration of structural integrity of ageing ships and marine platforms. This project will research the deterioration of structural integrity and remaining life of marine assets such as ships and offshore energy facilities, by integrating structural response analysis methods with aged-structure assessment techniques. Maritime assets exposed to ocean conditions suffer from time dependent phenomena, which reduce structural capability, affect safety and could have catastrophic environmental and economic consequences. Making assets available and affordably safe is a problem for operators. The key to prolonging asset life is in understanding the interrelationships over time between the asset’s structural condition and its use. Anticipated outcomes are superior safety, expected lifetime and economic benefits of maritime assets.Read moreRead less
Ship response under corrosion, fatigue and complex sea-state environments. This project will improve understanding of the gradual deterioration of ships and maritime structures subject to metal corrosion, fatigue and extreme sea-state conditions. Increasingly such understanding is necessary for optimal asset management decisions. These include the potential economic, personnel and other risks involved for ship owners and operators, including the Royal Australian Navy (RAN). The project will use ....Ship response under corrosion, fatigue and complex sea-state environments. This project will improve understanding of the gradual deterioration of ships and maritime structures subject to metal corrosion, fatigue and extreme sea-state conditions. Increasingly such understanding is necessary for optimal asset management decisions. These include the potential economic, personnel and other risks involved for ship owners and operators, including the Royal Australian Navy (RAN). The project will use numerical simulation. It will tackle the Fluid-Structure Interaction problem of ships in waves by integrating Finite Element structural response analysis with cutting-edge Smoothed Particle Hydrodynamics methods. The outcomes will provide new insight into remaining asset life and for exploring optimal maintenance strategiesRead moreRead less
ACTIVE CONTROL OF SURFACE OCEAN SHIPS. This research is to design nonlinear robust adaptive control systems using active actuators (flaps, fins and rudders) for course keeping and path tracking of surface ocean ships, which are inherently nonlinear and with uncertainties. The outcome of the research will lead to the development of non-linear control strategies, which result in simple-to-implement and effective controllers. These controllers are robust to the environmental disturbances and uncert ....ACTIVE CONTROL OF SURFACE OCEAN SHIPS. This research is to design nonlinear robust adaptive control systems using active actuators (flaps, fins and rudders) for course keeping and path tracking of surface ocean ships, which are inherently nonlinear and with uncertainties. The outcome of the research will lead to the development of non-linear control strategies, which result in simple-to-implement and effective controllers. These controllers are robust to the environmental disturbances and uncertainties, adapt to unknown parameters of the ship and actuators. Only a few control gains are required to be tuned. The success of this project will significantly increase the international competiveness of Australian shipbuilding industry.Read moreRead less
Coordination control of underactuated ocean vehicles for ocean forecasting. Australia is surrounded by oceans. Ocean forecasting is essential for effective and efficient operations on and within the ocean for a number of applications such as coastal zone management, military operations and scientific research. The successful completion of this project promises to put Australia in a leading position in this area. Due to the multi-disciplinary nature of this project, the project development will a ....Coordination control of underactuated ocean vehicles for ocean forecasting. Australia is surrounded by oceans. Ocean forecasting is essential for effective and efficient operations on and within the ocean for a number of applications such as coastal zone management, military operations and scientific research. The successful completion of this project promises to put Australia in a leading position in this area. Due to the multi-disciplinary nature of this project, the project development will also stimulate the development in many other areas such as new ocean vehicles, sensors and actuators, electronics and control.Read moreRead less
Forecasting wave breaking in directional seas. Wave breaking in Australia's coastal and open ocean regions has significant consequences for weather forecasting, marine safety, defence and renewable energy, yet no conceptual or computing framework exists for this fundamental process. This innovative project extends our recent advances in predicting wave breaking onset and strength of unidirectional wave groups to forecast breaking in realistic directional wind seas. The results of this project wi ....Forecasting wave breaking in directional seas. Wave breaking in Australia's coastal and open ocean regions has significant consequences for weather forecasting, marine safety, defence and renewable energy, yet no conceptual or computing framework exists for this fundamental process. This innovative project extends our recent advances in predicting wave breaking onset and strength of unidirectional wave groups to forecast breaking in realistic directional wind seas. The results of this project will provide the scientific basis needed to include reliable breaking wave information in forecast models, and will improve their accuracy. It will also increase the international competitiveness of Australian commerce reliant on accurate marine environmental forecasts.
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Automated helicopter hover and recovery system for operations at sea. The small size and simplicity of the integrated system outlined in this project will significantly improve the effectiveness of maritime surveillance for homeland security whilst enabling substantially lower operational costs. The proposal aims to develop control and sensing techniques, enabling small rotary wing unmanned air-vehicles (UAVs) weighing less than 100 kgs to operate from small-size vessels. This will be achieved ....Automated helicopter hover and recovery system for operations at sea. The small size and simplicity of the integrated system outlined in this project will significantly improve the effectiveness of maritime surveillance for homeland security whilst enabling substantially lower operational costs. The proposal aims to develop control and sensing techniques, enabling small rotary wing unmanned air-vehicles (UAVs) weighing less than 100 kgs to operate from small-size vessels. This will be achieved by resolving the current lack of integration between ship motion and the unmanned vehicle guidance systems. The proposed research will make substantial contributions in areas of ship motion prediction and sensing and hover control of tethered and non-tethered small helicopters.
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Optimal nose shaping for delayed boundary-layer separation and transition in axisymmetric flow. The aim of this project is to design a smooth nose for a body of revolution placed in axisymmetric flow of a viscous fluid at high Reynolds number, such that the boundary layer on the body remains unseparated. This can always be done with a sufficiently long nose, but our objective here is to minimise the necessary nose length. Outer potential flows will be provided via ring sources. The potential flo ....Optimal nose shaping for delayed boundary-layer separation and transition in axisymmetric flow. The aim of this project is to design a smooth nose for a body of revolution placed in axisymmetric flow of a viscous fluid at high Reynolds number, such that the boundary layer on the body remains unseparated. This can always be done with a sufficiently long nose, but our objective here is to minimise the necessary nose length. Outer potential flows will be provided via ring sources. The potential flows will be used to determine inner boundary layer solutions. Transition-to-turbulence will be considered by undertaking 2D and 3D stability computations.Read moreRead less
Geometry of wall-turbulence and its potential to advance scalable models. This project aims to unravel the connections between the statistical geometry of wall-turbulence and the dynamical interactions of its instantaneous motions. Predicting the complex behaviour of turbulent fluid flow over surfaces in relative motion is central to atmospheric modelling for climate and agriculture, and reducing the environmental effect of fossil fuel usage. Wall-turbulence statistics organise according to a pr ....Geometry of wall-turbulence and its potential to advance scalable models. This project aims to unravel the connections between the statistical geometry of wall-turbulence and the dynamical interactions of its instantaneous motions. Predicting the complex behaviour of turbulent fluid flow over surfaces in relative motion is central to atmospheric modelling for climate and agriculture, and reducing the environmental effect of fossil fuel usage. Wall-turbulence statistics organise according to a predictable geometric structure, and the notorious complexity of turbulent wall-flow dynamics could be clarified through its inherent geometry. This project expects to construct a basis for predicting engineering and atmospheric wall-flows, which would enhance atmospheric flow prediction, reduce energy consumption and further environmental sustainability.Read moreRead less