Gabriel Scherer

Considering the difficulty and complexity involved in choosing an agricultural aircraft, it is proposed to rank agricultural aircraft based on linguistic evaluations of their qualities. Aiming this, it is used an algorithm based on the Analytical Hierarchy Process (AHP) method and in the Technique of Order of Preference by Similarity to Ideal Solution (TOPSIS). The linguistic parameterization is made by using triangular fuzzy numbers. The method can be also used in other selection problems and… Show more

Considering the difficulty and complexity involved in choosing an agricultural aircraft, it is proposed to rank agricultural aircraft based on linguistic evaluations of their qualities. Aiming this, it is used an algorithm based on the Analytical Hierarchy Process (AHP) method and in the Technique of Order of Preference by Similarity to Ideal Solution (TOPSIS). The linguistic parameterization is made by using triangular fuzzy numbers. The method can be also used in other selection problems and in conceptual design phase in order to choose aircraft configurations.
Show less

This paper addresses the problem of estimating the attitude of a fixed wing Unmanned Aerial Vehicle (UAV) using a low cost Micro-Electro-Mechanical Sensors (MEMS) inertial measurement unit aided by a three axes magnetometer. The outputs of these devices have inherent noise and additive biases. Using quaternions to conjugate successive small rotations given by the gyroscopes and the other sensors to estimate long term attitude, a filtered observer was applied with spherical linear interpolation… Show more

This paper addresses the problem of estimating the attitude of a fixed wing Unmanned Aerial Vehicle (UAV) using a low cost Micro-Electro-Mechanical Sensors (MEMS) inertial measurement unit aided by a three axes magnetometer. The outputs of these devices have inherent noise and additive biases. Using quaternions to conjugate successive small rotations given by the gyroscopes and the other sensors to estimate long term attitude, a filtered observer was applied with spherical linear interpolation (SLERP) to merge these two estimations. This allowed for achieving good performance in both high and low frequencies. The accelerometer data includes a component of the airframe acceleration, which was estimated using a simple centripetal force model. This model can be extended in order to give better results using angular alpha and beta measurements. The magnetometer measurements were parallel to earth's field, which was modeled by the 11th IGRF spherical harmonic expansion. Filter's performance evaluation was done with a flight simulator data stream affected by simulated random walk noise, constant bias, nonlinearities and misalignments. The resulting estimation was compared to the actual values of the simulator. As conclusion, the resulting system is suitable for implementation on embedded hardware and estimates the attitude with good precision, becoming a possible choice for UAVs. Show less

A parallel propeller system was successfully controlled by a PID controller with gains adjusted by fuzzy sets. Parallel propeller system is composed by three pairs of bearings which permits movements in three degrees of freedom, the yaw, pitch and roll. The system has two propellers and electric motors. The roll and yaw movements are coupled due to the geometry of the system and the number of propellants. It’s a useful tool to study control in
helicopters and other rotor aircrafts. Fuzzy… Show more

A parallel propeller system was successfully controlled by a PID controller with gains adjusted by fuzzy sets. Parallel propeller system is composed by three pairs of bearings which permits movements in three degrees of freedom, the yaw, pitch and roll. The system has two propellers and electric motors. The roll and yaw movements are coupled due to the geometry of the system and the number of propellants. It’s a useful tool to study control in
helicopters and other rotor aircrafts. Fuzzy controller was designed to determine the gains for a PID control system
which controls the attitude of the parallel propeller system. Fuzzy sets use the desired attitude and the system’s state to
determine the gains of the PID controller. The error signal used in the PID is the difference between the desired angle
of attitude and actual angle of attitude. This error is used to calculate the voltage signal sent to each engine. This
controller was used in the parallel propeller system designed by the Airspace Control Laboratory of Escola de Engenharia de São Carlos of USP and its results can be used as a base in studies of controller for similar system or aircraft and the development of a fuzzy-PID-based control system to be used in unmanned aerial vehicles. Show less

This work approaches the conceptual design of an aircraft using a combination of three innovative tools. Genetic Algorithm is used in order to find the optimum solution inside the search space. Generated conceptual aircrafts are evaluated by AHP and TOPSIS in fuzzy environment. These tools allowed the creation of a complete system for multidisciplinary optimization that was tested in an aircraft conceptual design and achieved good performance. The main limitation of the method is the need of… Show more

This work approaches the conceptual design of an aircraft using a combination of three innovative tools. Genetic Algorithm is used in order to find the optimum solution inside the search space. Generated conceptual aircrafts are evaluated by AHP and TOPSIS in fuzzy environment. These tools allowed the creation of a complete system for multidisciplinary optimization that was tested in an aircraft conceptual design and achieved good performance. The main limitation of the method is the need of creating a good model to determine operational performance from general characteristics. Show less