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This paper addresses the problem of generating a position trajectory with pointing direction constraints at given waypoints for underactuated unmanned vehicles. The problem is initially posed on the configuration space ℝ 3 × ℝ 2 and thereafter, upon suitable modifications, is re-posed as a problem on the Lie group SE(3). This is done by determining a vector orthogonal to the pointing direction and using it as the vehicle's thrust direction. This translates to converting reduced attitude constraints to full attitude constraints at the waypoints. For the position trajectory, in addition to position constraints, this modification adds acceleration constraints at the waypoints. For real-time implementation with low computational expenses, a linear-quadratic regulator (LQR) approach is adopted to determine the position trajectory with smoothness upto the fourth time derivative of position (snap). For the attitude trajectory, the thrust direction extracted from the position trajectory is used to first propagate the attitude to the subsequent waypoint and then correct it over time to achieve the desired attitude at this waypoint. Finally, numerical simulation results are presented to validate the trajectory generation scheme.
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Attitude Pointing Control using Artificial Potentials with Control Input Constraints
This paper presents a novel approach for pointing direction control of a rigid body with a body-fixed sensor, in the presence of control constraints and pointing direction constraints. This scheme relies on the use of artificial potentials where an attractive artificial potential is placed at the desired pointing direction and a repulsive artificial potential is used to avoid an undesirable pointing direction. The proposed control law ensures almost global asymptotic convergence of the rigid body to its desired pointing direction, while satisfying the control input constraints and avoiding the undesirable pointing direction. These theoretical results are followed by numerical simulation results that provide an illustration of the scheme for a realistic spacecraft pointing control scenario.
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- Award ID(s):
- 1938518
- PAR ID:
- 10287480
- Date Published:
- Journal Name:
- 2021 American Control Conference (ACC)
- Page Range / eLocation ID:
- 1 to 6
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.23919/ACC50511.2021.9483350
