Fluid Dynamic Actuators For Satellite Attitude Control
thesisposted on 2021-05-24, 11:06 authored by Sobhan Etemadi
In this thesis, the application of fluid based actuators for satellite attitude control and thermal management is investigated. The actuator named Pumped Fluid Loop Actuator (PFLA) is examined to satisfy the need for integrated attitude and thermal management systems while considering strict mass and power budgets. A nonlinear voltage-driven control law is formulated and the feasibility of the PFLA for satellite attitude maneuvers is addressed. A high-fidelity PFLA model is developed. The power consumption of the PFLA is examined in the presence of sensor noise. Simulation results demonstrate its feasibility for attitude tracking capabilities of up to ± 0.01° with slew rates of up to 10 °/s. Next, the limitations of existing fluid dynamic actuators are overcome through the design of a novel Patent Pending Pumped Fluid Spherical Actuator (PFSA). The PFSA extends the capabilities of fluid dynamic actuators and allows for satellite attitude control about any arbitrary axis through spherical design, and introduces a fault-tolerant functionality that allows it to be used as a sensor in the event of rate-gyro failure of the attitude determination subsystem. The dynamic model of the PFSA is obtained through computational fluid-dynamics and finite-element analysis using the grid-independent solution. The passive stabilization capabilities of the PFSA are investigated. Simulation results show an order of three-fold reduction in settling time in comparison to existing fluid dynamic actuators. Lastly, a design modification is proposed for PFLA in order to examine its thermal management capabilities. A comprehensive investigation is carried out to perform thermal transport from onboard electronics through conduction and convection. Simulation results demonstrate the advantages of thermal transport while considering fluid rotation inside the PFLA as opposed to stationary fluid.