Modelling and design of nonlinear feedback control law for a large space hoop-column antenna

The problem of modelling and design of a nonlinear control law for the hoop-column antenna in orbit is presented. A 100-meter diameter reflector antenna is studied as a flexible body in a near-earth equatorial circular orbit. The dynamics of the body involve nonlinear coupled equations of rotational and generic modes. The generic modes involve the eigenfrequencies of the body. The main disturbances considered on the body are those due to the earth´s gravity gradient and vibration modes. A nonlinear control law (the receding horizon concept) is used to stabilize the antenna using linearised version of the equations of motion by retaining a finite number of truncated modes. The nonlinear control law design is compared with linear quadratic regulator controller implementation.