Browsing by Subject "Controls"

Now showing 1 - 3 of 3
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    Design and implementation of a control system for the Mesabi V27 wind turbine
    (2013-05) Thorson, William M.
    The focus of this thesis is the design and implementation of a control law for a Vestas V27 turbine. There are two motivations for this work. First, there is a rapidly growing industry to refurbish turbines and the proposed control design can be used to update V27 turbines to extend their operational life. Second, the proposed control design will be open-source thus enabling the V27 turbine to be used for research purposes. The thesis will first provide a review of traditional wind turbine control systems. Next the V27 turbine hardware, software, and design specification are described. A control system is then described that includes supervisory control and a SISO classical control for the rotor speed tracking controller. Experimental test results are presented using a V27 turbine installed at the Mesabi Range Community and Technical College.
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    The development of a power management strategy for a hydraulic hybrid passenger vehicle
    (2014-07) Meyer, Jonathan James
    The amount of energy being consumed is increasing each year, with the highest sector being the transportation industry. Within the transportation sector, the highest area of oil consumption is in the small and lightweight vehicle category. With increasing oil prices and decreasing supply, methods of reducing oil consumption have been studied. One is by developing a hybrid vehicle, which combines the internal combustion engine with an additional power source. For lightweight vehicles, electric hybrid vehicles have been thoroughly studied. While hydraulic hybrids have been studied for larger applications such as delivery trucks and buses, little research has been done in the area of small, lightweight vehicles. Hydraulics have a higher power density than electronics, so hydraulic hybrids can get better performance than electric hybrids while reducing fuel consumption.In this research, a series and power-split architecture is studied for a passenger vehicle. Because of the additional hydraulic power source along with energy storage, the optimal way to control these vehicles is not known. Therefore, an energy management strategy must be developed to determine the optimal strategy for splitting the power between the engine and the hydraulics.Three different methods are used to develop the energy management strategy - a rule-based strategy based on dynamic programming results, stochastic dynamic programming, and model predictive control. An experimental hardware-in-the-loop setup is used to replicate a series hybrid in which the different energy management strategies are tried. Through simulation and experimentation, it was found that not one strategy works best in all scenarios, and variables such as knowledge of duty cycle and energy storage must be taken into account when developing the strategy.An input-coupled power-split hybrid was also studied, which combines the mechanical efficiency of the parallel hybrid with the engine management of a series hybrid. Through a series of simulations, a strategy that declutched the engine from the drivetrain while the vehicle is stopped gave a significant reduction in fuel consumption. Another advantage of the power-split architecture is the ability to operate the vehicle in different modes by declutching the engine and removing hydraulic units by the use of valves. By using this strategy, the fuel economy can be almost doubled over a baseline strategy which operates only in power-split mode. Finally, the size of the accumulator can have an effect on the fuel consumption, with a smaller accumulator leading to less fuel consumed; however, if the accumulator is too small, the performance starts to degrade with a downsized engine.The results of this research can be used to develop a toolbox that can be used for developing energy management strategies by having the user enter a model, objective function, and duty cycle for a system. By using other information, such as knowledge of duty cycle, the toolbox can determine the best method of developing the control strategy, reducing the amount of time and resources for developing an optimal control strategy.
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    Modeling, Estimation, and Prototype Design for the Cable-Actuated Bio-inspired Lightweight Elastic Solar Sail
    (2023-08) Raab, Nathan
    Traditional spacecraft that utilize rocket engines for propulsion have a fundamental drawback in that they require the use of rocket fuel. As a result, there is a need to develop spacecraft with alternative means of propulsion that can extend the effective mission range without relying on heavy, expensive rocket fuel. One of the most promising alternative means of propulsion is the solar sail. These sails utilize the reflection of solar radiation pressure and the corresponding transfer of momentum to achieve propulsion. However, one of the most significant challenges pertaining to solar sail design is the means by which stabilization and attitude control are achieved. To address these challenges, this thesis presents the concept of the Cable-Actuated Bio-inspired Lightweight Elastic Solar Sail (CABLESSail). This novel solar sail concept uses cable-actuated flexible beams to achieve stabilization and attitude control by means of sail shape modulation. Analysis is shown that confirms the feasibility of the CABLESSail model by demonstrating that NASA mission attitude control requirements for both Solar Cruiser and Solar Polar Imager can be achieved through cable actuation. A method to predict the end-effector pose given the cable lengths or cable tension is discussed, with intended application in a control algorithm to control the end-effector pose. A prototype cable-driven continuum manipulator is designed for use as the cable-actuated flexible beam. The cable-driven continuum manipulator is modeled in simulation, and the simulation results of the beam deflection, induced cable torque, and the change in motor position are compared to experimental results.