Mechanical and Aerospace Engineering

MAE Ph. D. Exit Seminar- By Evan Sperber

Attitude Dynamics and Control of Solar Sails
By: Evan Sperber
Advisor: Professor Fidelis Eke

Solar sails are space vehicles that rely on solar radiation pressure in order to generate forces for thrust and attitude control torques. They exhibit characteristics such as large moments of inertia, fragility of various system components, and long mission durations that make attitude control a particularly difficult engineering problem. Sailcraft thrust vector control (TVC) is a family of attitude control techniques that is on a short list of strategies thought to be suitable for the primary attitude control of solar sails.  Every sailcraft TVC device functions by manipulating the relative location of the composite mass center of the sailcraft and the center of pressure of at least one of its reflectors.  Relative displacement of these two points results in body torques that can be used to steer the sailcraft. In this talk, an attitude control strategy is presented that is capable of reorienting a model sailcraft using TVC realized physically by fixing the sailcraft’s payload to the tip of a gimballed boom. By controlling the boom pitch angle about axes parallel to principal directions, it is possible to find a sequence of maneuvers that will reorient the sailcraft so that the membrane surface faces an arbitrary direction in space.  An algorithm that implements the proposed strategy is also presented and is applied to a range of model sailcraft sizes meant to span the design space for future missions suggested in the literature.  The model nonlinear equations of motion contain the control laws, and numerical simulation is performed in order to show the efficacy of this approach, which proves to be successful at minimizing both attitude and rate errors.

Date(s) - 09/29/2014
3:00 pm - 5:00 pm

2130 Bainer - MAE Conference Room


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