Modelisation of a circuit microurban integrant a transistor (HBT) by a method iterative with auxiliary sources
In summary, auxiliary sources are modeled by an iterative method, a much more applied aspect to linked with the evolved functions. Which is able to be realized by the association of an active component (transistor HBT) with a passive planar structure, operating in the field of the microwaves.
A new approach for microstrip active antennas using modal F.F.T-algorithm
A full-wave fast wave concept iterative technique is developed to analyze single and stacked microstrip active antennas with arbitrary shape. The wave concept is developed to express the boundary conditions on the radiating surfaces in term of the waves, which are solved using the iterative technique. With the help of the modal FFT-algorithm an efficient code is developed which allows a rapid and accurate characterization of arbitrary shaped antennas embedded in single and multilayered dielectric without the trial functions usually used in the conventional integral method. The time saving factor is about 20 compared to the conventional numerical integral methods. Field distribution and input admittance are derived.
L1 Adaptive Controller for Attitude Control of Multirotors
In this work we show an application of L1 Adaptive control theory for attitude control of UAVs. We implement the flight control system on a multirotor to show robustness and precise attitude tracking in the presence of modeling uncertainties and environmental disturbances. We choose backstepping control architecture, since the kinematics and dynamics of multirotors in most cases can be written in strict feedback form. We further exploit the fact that the kinematics of the plant, while free of uncertainties, is nonlinear, which makes it highly suitable for dynamic inversion control at each level of backstepping. On the other hand, plant dynamics is uncertain and is affected by environmental disturbances such as wind gusts, unmodeled dynamics etc. Therefore, we consider 3 variants of the control architecture. The first method uses backstepping to determine the moment demand and augments it with the L1 adaptive controller to account for uncertainties and provide robustness with guaranteed transient performance. The second architecture apply the concept of L1 adaptive backstepping to the same problem; and the third architecture uses L1 backstepping for quaternion representation of the system dynamics, which helps to avoid the singularities associated with Euler angles.