Abstract: There exist periodic disturbances in the process of elliptical orbit formation maintaining control.In this paper,a linear periodically-varying optimal quadratic regulator is designed by combining the internal model principle with the characteristics of periodically-varying coefficients in dynamics equations.High accuracy of control is achieved by adding the disturbance internal models to the index in the optimal control.Numerical simulations show that the proposed controller containing some disturbance internal models can improve the formation maintaining accuracy a lot for the elliptical orbit.

Key words: formation flying, internal model control(IMC)theory, optimal control