1,136 research outputs found

    A Sliding Mode Control for a Sensorless Tracker: Application on a Photovoltaic System

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    The photovoltaic sun tracker allows us to increase the energy production. The sun tracker considered in this study has two degrees of freedom (2-DOF) and especially specified by the lack of sensors. In this way, the tracker will have as a set point the sun position at every second during the day for a period of five years. After sunset, the tracker goes back to the initial position (which of sunrise). The sliding mode control (SMC) will be applied to ensure at best the tracking mechanism and, in another hand, the sliding mode observer will replace the velocity sensor which suffers from a lot of measurement disturbances. Experimental measurements show that this autonomic dual axis Sun Tracker increases the power production by over 40%

    Space programs summary no. 37-64, volume 1 for the period 1 May to 30 June 1970. Flight projects

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    Mariner and Viking flight projects for Mars exploratio

    Sun Tracking Systems: A Review

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    The output power produced by high-concentration solar thermal and photovoltaic systems is directly related to the amount of solar energy acquired by the system, and it is therefore necessary to track the sun's position with a high degree of accuracy. Many systems have been proposed to facilitate this task over the past 20 years. Accordingly, this paper commences by providing a high level overview of the sun tracking system field and then describes some of the more significant proposals for closed-loop and open-loop types of sun tracking systems

    Photovoltaic MPPT techniques comparative review

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    Control of Solar Power Systems: a survey

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    9th International Symposium on Dynamics and Controlof Process Systems (DYCOPS 2010)Leuven, Belgium, July 5-7, 20109This paper deals with the main control problems found in solar power systems and the solutions proposed in literature. The paper first describes the main solar power technologies, its development status and then describes the main challenges encountered when controlling solar power systems.Ministerio de Ciencia y Tecnología DPI2008-05818Ministerio de Ciencia y Tecnología DPI2007-66718-C04-04Junta de Andalucía P07-TEP-0272

    A Comparison of PID and Sliding Mode Controllers When Applied to the Orbit Raising of a Satellite Using Solar Sail Propulsion

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    Solar Sail spacecraft have become increasingly popular due to their ability to perform long term missions without the need for propellant. Because solar sail propulsion is so unique, most research has been focused on developing new mechanical control techniques. However, it can be argued that more advanced control algorithms can be used to mitigate the shortcomings of commonly used control actuators, specifically reaction wheels, when applied to solar sails. This thesis will research how a sliding mode controller compares to a PID controller with respect to settling time and state response error over a range of maximum reaction wheel torque values. The actuator saturation and actuator energy are then compared for two different sliding mode controllers and a PID controller. It was found that the sliding mode controller performed at minimum 14% better in terms of settling time and 7.7% better in terms of state response error, however the PID controller performed 24% better in terms of actuator saturation and energy. Further research should be done to study the potential benefits of sliding mode controllers in terms of their benefits to reduce actuator saturation and energy

    Space programs summary no. 37-63, volume 1 for the period 1 March - 30 April 1970. Flight projects

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    Mariner Mars 1971, Mariner Venus-Mercury 1973 and Viking Orbiter 1975 status report

    Control of a Solar Energy Systems

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    8th IFAC Symposium on Advanced Control of Chemical ProcessesThe International Federation of Automatic Control Singapore, July 10-13This work deals with the main control problems found in solar power systems and the solutions proposed in literature. The paper first describes the main solar power technologies, its development status and then describes the main challenges encountered when controlling solar power systems. While in other power generating processes, the main source of energy can be manipulated, in solar energy systems, the main source of power which is solar radiation cannot be manipulated and furthermore it changes in a seasonal and on a daily base acting as a disturbance when considering it from a control point of view. Solar plants have all the characteristics needed for using industrial electronics and advanced control strategies able to cope with changing dynamics, nonlinearities and uncertainties.Ministerio de Ciencia e Innovación PI2008-05818Ministerio de Ciencia e Innovación DPI2010-21589-C05-01/04Junta de Andalucía P07-TEP-0272

    Adaptive-Optimal Control of Spacecraft near Asteroids

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    Spacecraft dynamics and control in the vicinity of an asteroid is a challenging and exciting problem. Currently, trajectory tracking near asteroid requires extensive knowledge about the asteroid and constant human intervention to successfully plan and execute proximity operation. This work aims to reduce human dependency of these missions from a guidance and controls perspective. In this work, adaptive control and model predictive control are implemented to generating and tracking obstacle avoidance trajectories in asteroid’s vicinity. Specifically, direct adaptive control derived from simple adaptive control is designed with e modification to track user-generated trajectories in the presence of unknown system and sensor noise. This adaptive control methodology assumes no information on the system dynamics, and it is shown to track trajectories successfully in the vicinity of the asteroid. Then a nonlinear model predictive control methodology is implemented to generate obstacle avoidance trajectories with minimal system information namely mass and angular velocity of the asteroid. Ultimately, the adaptive control system is modified to include feed-forward control input from the nonlinear model predictive control. It is shown through simulations that the new control methodology names direct adaptive model predictive control (DAMPC), is able to generate sub-optimal trajectories. A comparative study is done with Asteroid Bennu, Kleopatra and Eros to show the benefits of DAMPC over adaptive control and MPC. A study on effect of noisy measurements and model is also conducted on adaptive control and direct adaptive model predictive control
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