Wilhelm, J., Close, J., and Huebsch, W., "Guidance and Range Extension Control System for a Hybrid Projectile," SAE Technical Paper 2014-01-2175, 2014, doi:10.4271/2014-01-2175.
A Hybrid Projectile (HP) is a ballistically launched round that transforms into an Unmanned Aerial Vehicle (UAV) at a designated point during flight. Aerodynamic control surfaces and associated control laws were sought that would extend the projectile's range using body lift and include guidance for a selected point of impact. Several challenges were encountered during the modification of an existing projectile, in this case a 40mm round, to achieve range extension and controllability. The control surfaces must be designed to allow for de-spin, controllability, and natural static stability. Also, a control system with laws and guidance relationships between heading, pitch or glide rate, and the associated aerodynamic surface movements needed to be developed. The designed aerodynamic surfaces, external ballistics, and control methods developed were modeled in a projectile flight simulator built in MATLAB. The base model was an M781 practice round and the aerodynamic coefficients and mass data were found in literature. Projected performance results show that developed tail design and control laws were able to maneuver the designed HP up to 2,500 diameters off the original line of fire and extend range up to 25%, effectively balancing range extension and guidance.