Session
Session VIII: FJR Student Competition
Location
Utah State University, Logan, UT
Abstract
As the small-satellite market grows, so does the demand for large-scale small-satellite missions with diverse payload functions. To facilitate mission planning, and to enable autonomous transition between payload operations, real-time on-board slew maneuver path planning is often required to reorient the spacecraft. The computed trajectory must take into account a variety of kinematic and dynamic constraints on the spacecraft attitude, angular velocity and actuator limits. It is also desirable to compute this trajectory such that it is optimal in some sense. To simplify computation, current applications typically employ a “rest-to-rest” assumption where the maneuver endpoints are assumed to be inertially fixed, leading to long settling times in practice when dynamic endpoints exist. This settling time prohibits command of maneuvers in quick succession, which can limit operational capabilities. By posing the calculation as a convex semidefinite programming optimization problem, this paper presents a computationally attractive path-planning algorithm that computes an optimal fixed-time trajectory between arbitrary endpoints, while satisfying a variety of common attitude control constraints. In addition, a closed-form iterative solution for a minimum-time maneuver is proposed. Both methods are validated in a simulation case involving the University of Toronto Institute for Aerospace Studies Space Flight Laboratory’s (UTIAS-SFL) next-generation DEFIANT-class spacecraft.
Real-Time Optimal Slew Maneuver Planning for Small Satellites
Utah State University, Logan, UT
As the small-satellite market grows, so does the demand for large-scale small-satellite missions with diverse payload functions. To facilitate mission planning, and to enable autonomous transition between payload operations, real-time on-board slew maneuver path planning is often required to reorient the spacecraft. The computed trajectory must take into account a variety of kinematic and dynamic constraints on the spacecraft attitude, angular velocity and actuator limits. It is also desirable to compute this trajectory such that it is optimal in some sense. To simplify computation, current applications typically employ a “rest-to-rest” assumption where the maneuver endpoints are assumed to be inertially fixed, leading to long settling times in practice when dynamic endpoints exist. This settling time prohibits command of maneuvers in quick succession, which can limit operational capabilities. By posing the calculation as a convex semidefinite programming optimization problem, this paper presents a computationally attractive path-planning algorithm that computes an optimal fixed-time trajectory between arbitrary endpoints, while satisfying a variety of common attitude control constraints. In addition, a closed-form iterative solution for a minimum-time maneuver is proposed. Both methods are validated in a simulation case involving the University of Toronto Institute for Aerospace Studies Space Flight Laboratory’s (UTIAS-SFL) next-generation DEFIANT-class spacecraft.
