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Introduction--An Unmanned Aircraft UAV or UAVS, for its acronym in English, is one capable of performing a flight without the need for a pilot on board. The control techniques applied in unmanned aircraft systems are used to improve the performance and stability of these systems. Several control techniques have been created to automate systems, aiming to improve the performance of these looking for optimal performance conditions. Quadrotors are a type of unmanned aerial vehicle that is currently used due to its ease of Vertical Take-Off and Landing (VTOL), it is an ideal system to apply control laws because of its non-linearity and its unstable behavior in the face of external disturbances, usually environmental variables. Objective--Establish the advantages of the implementation of a robust control based on linear matrix inequalities, compared to a state feedback controller implemented in a quadrotor type unmanned aerial vehicle. Methodology--Two linear control strategies were designed and implemented: control by location of poles and zeros, and control based on Linear Matrix Inequalities LMI; therefore, in this work a linear model of the quadrotor represented in state variables was used. Results--The controllers are stable against external disturbances and disturbances caused by the environment. For the Pitch and Roll angles, the set point was adjusted to 0 degrees, and for the yaw angle, the set point was adjusted to 100 degrees. This paper shows the performance of the control strategy based on LMIs, short response times and maintains an equilibrium point between -2 and 2 degrees on each axis, allowing the quadrotor to stabilize at each angle of rotation. Conclusions--The controller based on LMIs has multiple advantages compared to the state feedback control strategy, since it allows the inclusion of several controller design criteria such as: the control input, the poles location, the definition of the infinite H norm, uncertainties, and disturbances. In addition, the LMIbased controller is presented as a solution to be implemented in a real system as it significantly improved the maximum overshoot, the response to external disturbances, the response time and quadrotor stabilization in the tests carried out. [ABSTRACT FROM AUTHOR]

This paper shows a robust control strategy to address the inter-area oscillations in power systems using PSS's. The approach is based on the well-known Δω strategy of Kundur, and it was modified to take into account remote signals of the whole power system. The control center computes control signals for each generator in the system weighting the different measurements of each active generator. The robustness of the approach allows to face the communications delays due to remote measures. The strength of the proposed technique is validated through simulations over the Kundur two-areafour- machines test case power system, here it was used the complete model for the generators. The inter-area oscillations after a three-phase fault were successfully damped; also, the latencies which add instability in closed loop were faced. [ABSTRACT FROM AUTHOR]