This article presents the design and implementation of an event-triggered control approach, applied to the leader-following consensus and formation of a group of autonomous micro-aircraft with capabilities of vertical take-off and landing (VTOL-UAVs). The control strategy is based on an inner–outer loop control approach. The inner control law stabilizes the attitude and position of one agent, whereas the outer control follows a virtual leader to achieve position consensus cooperatively through an event-triggered policy. The communication topology uses undirected and connected graphs. With such an event-triggered control, the closed-loop trajectories converge to a compact sphere, centered in the origin of the error space. Furthermore, the minimal inter-sampling time is proven to be below bounded avoiding the Zeno behavior. The formation problem addresses the group of agents to fly in a given shape configuration. The simulation and experimental results highlight the performance of the proposed control strategy.
In this paper a Fractional PID Control is presented. This control was designed for a hydropower plant with six generation units working in an alternation scheme. The parameters and other features of such a set of hydrogeneration units have been used to perform the respective tuning up. In order to assess the behavior of this controlled system, a model of such nonlinear plant is regulated through a classical PID by classical linearization of its set points, and then a pseudo-derivative part is substituted into a Fractional PID. Both groups of signals contain variations of voltage suggesting some abrupt changes in the supply of electricity fed to the network. Both sets of resulting signals are compared; the simulations show that the Fractional PID has a faster response with respect to those plots obtained from the classical PID used.
In this paper, the effect of antenna sectorization in the reverse link Erlang capacity of a multiclass code-division multiple-access (CDMA) cellular system is studied. Traditionally, it has been considered that the capacity is multiplied by a factor equal to the number of sectors introduced. This is true only in the ideal antenna sectored system. However, due to the nonideal antenna radiation pattern, the sectorization gain is smaller than the number of sectors. Our contribution is the analytical study of the effect of nonideal antenna patterns on the capacity of a multiclass CDMA system. We also present an approximated analysis of the Erlang capacity, considering that blocking in CDMA occurs when the interference reaches a predetermined level above the background noise level of mainly thermal origin. The analysis also includes the effects of imperfect power control and service activity detection. We found that the capacity losses due to the consideration of antenna sectorization are about 20.20% for the nonideal antenna radiation pattern and 30.32% for the evaluated commercial radiation pattern. This percentage loss implies that the sectorization gain is approximately 2.39 for a nonideal antenna pattern and 2.09 for a commercial antenna pattern in typical conditions, = 4 and = 8 dB.
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