ANALYSIS AND DESIGN OF SPACE VEHICLE FLIGHT CONTROL SYSTEMS VOLUME I - SHORT PERIOD DYNAMICS

摘要

The performance quality of a space launch vehicle during the launch phase of flight is generally studied in two distinct, though related, phases. The first deals with the trajectory of the vehicle with reference to some specified inertial frame and is concerned with such factors as payload capacity, dispersions from nominal, and orbit capability. Dispersion of the actual from nominal trajectory due to such factors as parameter uncertainty and random loads is generally referred to as 'long period dynamics. " In this context, the vehicle is usually assumed to be a point mass and the oscillations about the nominal trajectory have a 'long" period. However, the action of the control system in orienting the vehicle is not instantaneous. Oscillations about the vehicle center of mass are induced and these must be damped out if the mission is to be successful. These oscillations have a comparatively short period and the study of these motions constitutes the subject matter of the vehicle "short period dynamics."