Flight Control of a Small-Diameter Spin-Stabilized Projectile Using Imager Feedback

Small-diameter gun-launched projectiles pose a challenging platform on which to implement closed-loop guidance and control. This paper presents a novel imager-based guidance and control algorithm for small-diameter spin-stabilized projectiles. The control law is specifically formulated to rely on feedback only from a strapdown detector and roll angle sensors. Following introduction of the projectile nonlinear dynamic model, an integrated guidance and control algorithm is presented in which control commands are computed directly from detector feedback using a gain-scheduled proportional control. Time-varying controller gains are derived through a surrogate modeling approach, and controller performance is further enhanced through use of an observer that filters unwanted angular motion components from detector feedback. Example closed-loop flight simulations demonstrate performance of the proposed control system, and MonteCarlo analysis shows a factor of 2 accuracy improvement for the closed-loop system over ballistic flight. Results indicate that delivery system improvements are achievable in small, gyroscopically stabilized projectiles containing low-cost guidance elements using the proposed integrated guidance and control approach.