Impact point model predictive control of a spin-stabilized projectile with instability protection

Abstract

Most smart projectile control systems generate lateral control forces to guide the round to a target. Experience has shown that under the right combination of body orientation, translational velocity, and angular velocity, relatively low lateral control force inputs can induce instability of the round. To solve this problem, an additional control logic layer is appended to a nominal impact point flight control law to protect it from instability in these infrequent, but consequential situations. To highlight the newly developed control logic, a smart 155 mm spin-stabilized projectile equipped with a rotating paddle control mechanism is considered. For this example configuration, cross range maneuvering occasionally induces instability. Simulation results, using both rigid and multi-body nonlinear flight dynamics models, indicate that the addition of the instability protection layer in the control logic prevents projectile instability while not substantially altering target impact statistics. The nature of this protector design lends itself well to the use of a GPU to perform the calculations, greatly decreasing the computation time needed.