299,654 research outputs found

    Modeling and Robust Attitude Controller Design for a Small Size Helicopter

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    This paper addresses the design and application controller for a small-size unmanned aerial vehicle (UAV). In this work, the main objective is to study the modeling and attitude controller design for a small size helicopter. Based on a non-simplified helicopter model, a new robust attitude control law, which is combined with a nonlinear control method and a model-free method, is proposed in this paper. Both wind gust and ground effect phenomena conditions are involved in this experiment and the result on a real helicopter platform demonstrates the effectiveness of the proposed control algorithm and robustness of its resultant controller.Comment: 6 page

    A γγ\gamma\gamma Collider for the 750 GeV Resonant State

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    Recent data collected by ATLAS and CMS at 13 TeV collision energy of the LHC indicate the existence of a new resonant state ϕ\phi with a mass of 750 GeV decaying into two photons γγ\gamma\gamma. The properties of ϕ\phi should be studied further at the LHC and also future colliders. Since only ϕγγ\phi \to \gamma\gamma decay channel has been measured, one of the best ways to extract more information about ϕ\phi is to use a γγ\gamma\gamma collider to produce ϕ\phi at the resonant energy. In this work we show how a γγ\gamma\gamma collider helps to verify the existence of ϕ\phi and to provide some of the most important information about the properties of ϕ\phi, such as branching fractions of ϕV1V2\phi\to V_1V_2. Here ViV_i can be γ\gamma, ZZ, or W±W^\pm. We also show that by studying angular distributions of the final γ\gamma's in γγϕγγ\gamma\gamma \to \phi \to \gamma\gamma, one can obtain crucial information about whether this state is a spin-0 or a spin-2 state.Comment: ReTex, 12 page with 6 figures. Expanded discussion on distinguishing spin-0 and spin-2 cases. Several figures adde

    Two Particle States in a Box and the ss-Matrix in Multi-Channel Scattering

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    Using a quantum mechanical model, the exact energy eigenstates for two-particle two-channel scattering are studied in a cubic box with periodic boundary conditions. A relation between the exact energy eigenvalue in the box and the two-channel SS-matrix elements in the continuum is obtained. This result can be viewed as a generalization of the well-known L\"uscher's formula which establishes a similar relation in elastic scattering.Comment: 4 pages, typeset with ws-ijmpa.cls. Talk presented at International Conference on QCD and Hadronic Physics, June 16-20, 2005, Beijing, China. One reference adde