An optimal control approach to robust control of nonlinear spacecraft rendezvous system with θ-D technique

In this paper, a new optimal robust control design approach is proposed for the task of spacecraft rendezvous such that both the stabilization and optimal performance are achieved. An approximate closed-form solution to the nonlinear optimal control problem is obtained by employing the θ-D technique, which is derived based on an approximate solution to the Hamilton-Jacobi-Bellman equation obtained via a perturbation technique. This approach provides a simple design procedure, and the feedback control law obtained is easy for on-board implementation. The effectiveness of the proposed approach is demonstrated through simulation studies