Unmanned Aerial Ve hicles (UAVs) are employed in surveillance, reconnaissance, and aerial photography. The dynamics of UAVs is highly nonlinear and inherently coupled. It also tends to vary continuously with time and is subjected to severe external disturbances. Due to this, dynamic and paramet ric uncertainties arise in the mathematical model of the UAVs over different operating conditions. In this paper, a controller is synthesised using Uncertainty and Disturbance Estimation (UDE) method. Simulation results prove the robustness of the designed control strategy against uncertainty and disturbance.
Spherical microphone arrays (SMAs) are widely used for sound recording and analysis, with processing being done in the spherical harmonics (SH) domain. This is due to the ease of array processing in the SH domain without spatial ambiguity. However, it is uneconomical to construct a full SMA when sources are present in restricted regions of the environment. Additionally, the use of a full SMA comes at the cost of more microphone signals to process. Attempts have been made to use hemispherical microphone arrays on the basis of the acoustic image principle, enabling application of SH but with greater computational complexity. In this paper, the use of a spherical sector microphone array instead of a full SMA is proposed. An orthonormal spherical sector harmonics (S2H) basis function is developed for accurate representation of pressure over the sector. The orthonormality of the S2H function is established using orthogonality of shifted associated Legendre polynomials and a scaled exponential function. An addition theorem for S2H basis functions is derived. The S2H basis function is applied to the decomposition of a sound field over a sector array. The S2H basis function has potential applications to brain source localization and physiological shape description.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.