Guidance and Control of a Man Portable Precision Munition Concept

Abstract

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 strap-down 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 Monte Carlo analysis shows a factor of two 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. mass [kg]This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. AIAA SciTech I moment of inertia matrix [kg-m 2 ] , ⁄ total velocity of projectile with respect to the wind, velocity of center of gravity with respect to inertial frame in body-fixed coordinates [m/s] atmospheric density [kg/m 3 ] dynamic pressure at projectile mass center [N/m 2 ] q M dynamic pressure at wing actuator center of pressure [N/m 2 ] Mach number √ pitch angle-of-attack [rad] √ yaw angle-of-attack [rad] √ √ total angle-of-attack [rad] aerodynamic roll angle [rad] , , aerodynamic forces acting on projectile [N] , , gravity forces acting on projectile [N] , , aerodynamic moments acting on projectile [Nm] , , total, zero-yaw, and yaw-dependent axial force coefficient , , , total, trim, linear and nonlinear normal force coefficient roll damping moment coefficient , , , total, trim, linear and nonlinear pitching moment coefficient pitch damping moment coefficient Magnus force coefficient Magnus moment coefficient , , , Wind actuator aerodynamic coefficients , axial center-of-pressure, radial CP [m] → vector from center-of-gravity to i th moveable Downloaded by NANYANG TECHNICAL UNIVERSITY on October 1, 2015 | http://arc.aiaa.org | aerodynamic surface center-of-pressure [m] , , , Φ, Earth-fixed commanded, Earth-fixed control, body-fixed control, relative, and stowed roll angles [rad] 1 0 0 0 Φ Φ 0 Φ Φ transformation matrix from body-fixed to moveable aerodynamic surface coordinates transformation matrix from body-fixed to Earthfixed coordinates transformation matrix from body-fixed to wing surface coordinates transformation matrix from velocity vector coordinates to Earth-fixed coordinates , , inertial position [m] , , inertial translational veloc...