The Experts below are selected from a list of 99126 Experts worldwide ranked by ideXlab platform
J E Faller - One of the best experts on this subject based on the ideXlab platform.
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a simple pendulum laser interferometer for determining the gravitational constant
Philosophical Transactions of the Royal Society A, 2014Co-Authors: Harold V Parks, J E FallerAbstract:We present a detailed account of our 2004 experiment to measure the Newtonian constant of gravitation with a suspended laser interferometer. The apparatus consists of two simple Pendulums hanging from a common support. Each pendulum has a length of 72 cm and their separation is 34 cm. A mirror is embedded in each pendulum bob, which then in combination form a Fabry–Perot cavity. A laser locked to the cavity measures the change in pendulum separation as the gravitational field is modulated due to the displacement of four 120 kg tungsten masses.
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a suspended fabry perot interferometer for determining the newtonian constant of gravitation
Proc. of SPIE Vol. 4269 Laser frequency stabilization standards measurement and applications: 24-26 January 2001, 2001Co-Authors: Harold V Parks, D S Robertson, Alan M Pattee, J E FallerAbstract:Of all the fundamental constants of nature, the Newtonian constant of gravitation, G, has been one of the most difficult to measure. The current CODATA value of G has an uncertainty of 1.5 parts in 1000. Although recent experiments have produced values with uncertainties smaller than this, the adopted CODATA uncertainty reflects the fact that there is still substantial disagreement between the values from these experiments. The majority of previous measurements have used torsion Pendulums or balances to convert the small gravitational attraction of a laboratory source mass into a relatively large mechanical displacement. However, our approach is to use simple Pendulums, which results in a small displacement that we measure very accurately. This means that the attraction of the source masses is measured against a restoring force provided by earth's gravity rather than the less well-understood torsion of a wire. Also, the shorter period of our Pendulums allows us to make measurements much more rapidly than in most other experiments. In our apparatus, two mirrors, each suspended as a simple pendulum, form a Fabry-Perot cavity. A He-Ne laser locked to this cavity monitors the relative displacement of these two Pendulums (through changes in its frequency) as laboratory source masses are moved, altering the gravitational pull on the mirrors.
L.i. Hui - One of the best experts on this subject based on the ideXlab platform.
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Numerical Simulation of the Pendulum System in a Buoy-pendulum Wave Energy Converter☆
Energy Procedia, 2014Co-Authors: He Hong-zhou, L.i. HuiAbstract:Abstract Sea conditions have a significant impact on the efficiency of wave energy converters (WECs). Based on the buoy-pendulum WEC presented in the paper, the energy-collection principle of the pendulum system is described, and the motion response of the Pendulums under three wave conditions is simulated. It is shown that the optimal wave direction for pendulum system's operation is 45°; the pendulum is apt to reach balance when wave height is less than 0.6 m. In addition, a method to estimate the average conversion efficiency of the pendulum system is proposed based on the fitting function software, and the efficiencies under five ideal wave conditions are calculated. The results show that the greater the wave period and the wave height, the lower the collection efficiency of the pendulum.
Luca Consolini - One of the best experts on this subject based on the ideXlab platform.
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synchronizing n cart Pendulums using virtual holonomic constraints
Advances in Computing and Communications, 2012Co-Authors: Dame Jankuloski, Manfredi Maggiore, Luca ConsoliniAbstract:A solution is presented to the problem of synchronizing a chain of N cart-Pendulums using virtual holonomic constraints. The approach is based on a master-slave configuration whereby the first cart-pendulum is controlled so as to stabilize a desired oscillation around its unstable equilibrium. Then, each remaining cart-pendulum is controlled so as to fully synchronize it to the previous pendulum.
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ACC - Synchronizing N cart-Pendulums using virtual holonomic constraints
2012 American Control Conference (ACC), 2012Co-Authors: Jankuloski, Manfredi Maggiore, Luca ConsoliniAbstract:A solution is presented to the problem of synchronizing a chain of N cart-Pendulums using virtual holonomic constraints. The approach is based on a master-slave configuration whereby the first cart-pendulum is controlled so as to stabilize a desired oscillation around its unstable equilibrium. Then, each remaining cart-pendulum is controlled so as to fully synchronize it to the previous pendulum.
He Hong-zhou - One of the best experts on this subject based on the ideXlab platform.
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Numerical Simulation of the Pendulum System in a Buoy-pendulum Wave Energy Converter☆
Energy Procedia, 2014Co-Authors: He Hong-zhou, L.i. HuiAbstract:Abstract Sea conditions have a significant impact on the efficiency of wave energy converters (WECs). Based on the buoy-pendulum WEC presented in the paper, the energy-collection principle of the pendulum system is described, and the motion response of the Pendulums under three wave conditions is simulated. It is shown that the optimal wave direction for pendulum system's operation is 45°; the pendulum is apt to reach balance when wave height is less than 0.6 m. In addition, a method to estimate the average conversion efficiency of the pendulum system is proposed based on the fitting function software, and the efficiencies under five ideal wave conditions are calculated. The results show that the greater the wave period and the wave height, the lower the collection efficiency of the pendulum.
M. Kaneda - One of the best experts on this subject based on the ideXlab platform.
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Analysis of the energy-based control for swinging up two Pendulums
IEEE Transactions on Automatic Control, 2005Co-Authors: M. KanedaAbstract:This note studies the energy-based control for swinging up two Pendulums on a cart and it presents an original analysis of the convergence of the energy and the motion of the two Pendulums. For the two Pendulums with the different natural frequencies, irrespective of initial state of the two Pendulums, it is shown that the energy of each pendulum converges to either of two values, and the motion of the two Pendulums can be described by four invariant sets. Moreover, the stability analysis of the motion of the two Pendulums is performed via the concept of stability of an invariant set. The results obtained in this note not only show theoretically the effectiveness of the energy-based control for swinging up the two Pendulums, but also pave one way for analyzing and designing the energy-based control for more complicated underactuated mechanical systems.
