Guidance and Control of Spin-Stabilized Projectiles Based on Super Twisting Algorithm
Akhil B. Krishna, Mangal Kothari, Amit Abhishek
Abstract
In this paper, a hybrid integrated guidance and control design exploiting the time-scale separation principle for a canard-guided dual-spin projectile (DSP) is proposed. The DSP consists of two parts: i) the aft part, which has a high spin rate for providing gyroscopic and aerodynamic stability, and ii) the forward part, which contains a course correction fuze that houses two pairs of movable canards to ensure precise interception. The guidance and control algorithms operate in a two-loop structure where the outer guidance loop generates required pitch and yaw rate commands, whereas the inner loop tracks these commands by generating canard deflections. The rolling motion of the forward part is controlled using a coaxial motor. The multibody dynamic model of DSP has seven degrees of freedom and is highly coupled and nonlinear. For the guidance, a finite horizon optimal control problem is formulated as an output regulation problem with output vector taken as pitch and yaw components of zero effort miss vector. A coupled pitch–yaw autopilot for pitch and yaw rate command tracking and a roll autopilot for roll stabilization of the forward part are designed based on super twisting algorithm. The efficacy of the control design is shown through numerical simulations.