Dynamics and control of large space platforms and small experimental payloads

A capability developed to study the dynamics and control of space platforms in connection with the generation, conversion and utilization of power in space is described. It is based on the use of both rigid and flexible models of platform configurations which may be rather arbitrary. The principal part of the capability is a digital simulation code which uses the results of analyses of finite element models of platforms to account for their flexibilities. By using the code, the general motion of fairly complex configurations including rotating components may be simulated. The control of gross attitude motion is accomplished via a minimum impulse limit cycle controller. Examples of gross attitude motion and "fine" motion due to flexibility are presented. Also, to illustrate the versatility of the code, results are presented of simulations of the motion of a small, suborbital, experimental payload which has deployable booms. Another aspect of the overall capability is spotlighted through an example of the attitude dynamics of the experiment carrying suborbital vehicle during boom deployment.