Tese: Numerical and experimental study of two degrees of freedom electrohydraulic manipulator
Aluno(a) : William Schroeder CardozoOrientador(a): Hans Weber
Área de Concentração: Mecânica Aplicada
Data: 26/07/2017
Link para tese/dissertação: http://doi.org/10.17771/PUCRio.acad.31839
Resumo: Thrust Vector Control (TVC) is used for the attitude control of spacecrafts. In the case of liquid-propellant fuel, the nozzle is traditionally connected to the rocket frame through a gimbal. Two hydraulic actuators are placed around the nozzle to control its orientation. In this Thesis, TVC is treated as a fixed base robotic platform. Instead of using commercial servo-valves to control the actuators, a novel control valve is proposed. First a gimbaled platform is considered with two angular position transducers to measure the angular displacement of the joint crosshead. Then, a homokinetic platform configuration is proposed replacing the gimbal by a constant velocity joint. In this case, the platform position feedback is done using a real-time attitude estimator. The estimator is a complementary filter based on orientation matrices that collects data from an inertial measurement unit (IMU). The modeling of the system begins with kinematics. Then, the dynamic modeling uses the Newton-Euler formulation to obtain the equation of motion. The modeling of the electro-hydraulic system is presented with the model of the novel control valve and the linear actuator. Initially, a full proportional controller is proposed. During the experimental validation it is shown that due to the characteristics of the actuation system, even this simple controller is accurate and reliable. Thereafter, it is demonstrated a method to evaluate novel control strategies. The comparison between the gimbaled and homokinetic platform shows that, under the analyzed conditions, they have a similar dynamic behavior. In both platform configurations the system is accurate and reliable.