Design and control of nose actuation kit for position correction of spin stabilized munitions under wind effect

Eroğlu, Mesut
Unguided munitions have been replaced with guided munitions over the century. There are two main reasons for this change; to increase damage to target with fewer munitions and reduce collateral damage due to deflection of munitions. Moreover, there are two options, building new guided munitions and modification of unguided munitions to convert dummy munitions to smart ones. Modifying unguided munitions to have guided munitions instead of building a completely new one is preferable due to economic reasons. This thesis aims at ensuring position correction for spin stabilized munitions under wind effect by using a one degree of freedom nose actuation mechanism. A model of the standard 155 mm spin stabilized munitions is created by PRODAS software to obtain aerodynamic coefficients. Aerodynamic coefficients are calculated between 0.6 and 3 Mach number for the model by the software. A computer code is developed that calculates the forces and moments acting on the munition by using the aerodynamic coefficients given by PRODAS. The code also calculates the trajectory by solving for the equations of motion. Results of the code developed are compared with results of PRODAS for verification. A mechanism that attaches to the nose of the munition with roll degree of freedom is designed. Two wings with a fixed incidence angle are mounted on the mechanism that creates a force normal to the axis of the mechanism. The orientation of the mechanism with respect to the munition can be controlled by an electric motor, which gives the ability to steer the munition as desired. Solid and dynamic models of the mechanism are derived and a controller is designed for its roll position. First the baseline munition without the mechanism is simulated with varying disturbance wind direction and magnitude to obtain munition dispersion zones due to wind effect. The same analysis is repeated with the mechanism with varying wing platform areas and roll angles. The roll angle of the mechanism is kept constant at the chosen value for each flight. These analyses yielded the optimum wing size that ensured stability with maximum effectiveness.
Citation Formats
M. Eroğlu, “Design and control of nose actuation kit for position correction of spin stabilized munitions under wind effect,” M.S. - Master of Science, Middle East Technical University, 2016.