Adaptive Output Feedback Control for Spacecraft Rendezvous and Docking Under Measurement Uncertainty

An output feedback structured model reference adaptive control law has been developed for spacecraft rendezvous and docking problem. The effect of bounded output errors on controller performance is studied in detail. Output errors can represent an aggregation of sensor calibration errors, systematic bias or some stochastic disturbances present in any real sensor measurements or state estimates. The performance of the control laws for stable, bounded tracking of the relative position and attitude trajectories is evaluated, considering un-modeled external as well as parametric disturbances and realistic position and attitude measurement errors. The essential ideas and results from computer simulations are presented to illustrate the performance of the algorithm developed in paper. Introduction Autonomous rendezvous and docking are essential for future autonomous space transportation missions such as ISS supply and repair, and space systems automated inspection, servicing and assembly. Autonomous proximity operations are required for a large number of future mission concepts yet, can not be routinely achieved at present. For the docking of two spacecraft, a highly precise and robust position and attitude control is required which further requires precise measurements of the relative position and attitude of docking spacecraft. These requirements have driven the identification, development and evaluation of ∗Accepted for Publication in AIAA Journal of Guidance,Control and Dynamics †Presented at 13th AAS/AIAA Space Flight Mechanics Meeting, Ponce, Puerto Rico, February 9-13, 2003 ‡Graduate Assistant Research, Student Member AIAA, Department of Aerospace Engineering, Texas A&M University, College Station, TX-77843, [email protected]. §Assistant Professor, AIAA Member, Department of Mechanical and Aerospace Engineering, University of Texas, Arlington, TX, [email protected]. ¶Distinguished Professor, George Eppright Chair, AIAA Fellow, Department of Aerospace Engineering, Texas A&M University, College Station, TX-77843, [email protected].