Improving two axes gimbal seeker performance using cascade control approach

Abstract

One of the most important components constituting a homing guided missile is the seeker which basically consists of a detector with a servo-tracking loop. The performance of gimbal seeker is evaluated according to the line of sight (LOS) stability. The purpose of this paper is to present, investigate, and analyze the performance of two axes gimbal seeker which must strictly isolate the LOS from the torque disturbances and missile vibrations. The equations of gimbals motion are derived using Lagrange equation considering the missile angular motion and gimbals mass unbalance. The stabilization loop is constructed by identifying its components, then the traditional and cascade loops are defined. The overall control system is built considering the cross coupling unit and simulated in MATLAB for the traditional and cascade control loops. A comparison study is carried out to investigate the gimbal seeker performance under different operational conditions such as missile rates and accelerations. The simulation results prove the efficiency of the proposed cascade control loop which offers better response more than traditional one, and improves further the transient and the steady-state response of two axes gimbal seeker system.