Accession Number : ADA112571

Title :   Rocket Launchers as Passive Controllers.

Descriptive Note : Final rept.,


Personal Author(s) : Cochran,John E , Jr ; Gunnels,Richard T ; McCutchen,Robert K , Jr

PDF Url : ADA112571

Report Date : 31 Dec 1981

Pagination or Media Count : 108

Abstract : A concept is advanced for using the motion of launchers of a free-flight launcher/rocket system which is caused by random imperfections of the rockets launched from it to reduce the total error caused by the imperfections. This concept is called 'passive launcher control' because no feedback is generated by an active energy source after an error is sensed; only the feedback inherent in the launcher/rocket interaction is used. Relatively simple launcher models with two degrees of freedom, pitch and yaw, were used in conjunction with a more detailed, variable-mass model in a digital simulation code to obtain rocket trajectories with and without thrust misalignment and dynamic imbalance. Angular deviations of rocket velocities and linear deviations of the positions of rocket centers of mass at burnout were computed for cases in which the launcher was allowed to move ('flexible' launcher) and was constrained so that it did not rotate ('rigid' launcher) and ratios of flexible to rigid deviations were determined. Curves of these error ratios versus launcher frequency are presented. These show that a launcher which has a transverse moment of inertia about its pivot point of the same magnitude as that of the centroidal transverse moments of inertia of the rockets launched from it can be tuned to passively reduce the errors caused by rocket imperfections.

Descriptors :   *Rocket launchers, *Artillery rockets, *Rocket trajectories, Launching, Free flight trajectories, Control systems, Passive systems, Interactions, Dynamic response, Digital simulation, Pitch(Motion), Yaw, Defects(Materials), Compensation, Burnout, Mass, Moment of inertia, Balance, Random variables, Thrust, Misalignment, Equations of motion, Errors, Ratios, Reduction, Pivots

Subject Categories : Armor

Distribution Statement : APPROVED FOR PUBLIC RELEASE