Adaptive synchronization and control of nonlinear dynamical systems.

摘要

Research in autonomous vehicles, especially for space applications, is important for the development of future technologies. Utilizing autonomous spacecraft for rendezvous and docking is a popular research subject due to its potential to save money for the satellite industry. This technology could also be used for logistic support and space debris removal, among other future applications. The research presented in this paper introduces nonlinear control laws for the purpose of maintaining docking orientation between spacecraft in orbit using attitude synchronization and relative position tracking. Disturbances due to gravity gradients, atmospheric drag, and solar radiation are included in the system equations in order to provide a realistic model. The stability of the control laws is proven implicitly using nonlinear stability theory and their performance is demonstrated via a high fidelity simulation. In addition, a vision based navigation model is constructed that provides measurements in order to estimate the relative position and relative velocity between the two spacecraft. The estimates are generated from a continuous-discrete extended Kalman filter (EKF) and used for feedback in the translation control law. The performance of the estimated state based controller is demonstrated using a simulation.