Autopilot Design for a LOS Anti-tank Guided Missile

Abstract

The performance of antitank guided missile systems is measured through the minimum missdistance and the capability of the missile to overcome target maneuver and different sources of errors and disturbance noises. The variety of new missiles with higher performance requirements impulse new problems in structure, effectiveness of control, cost, reliability...etc. One of the most interesting and challenging problem areas for antitank missile is that of the guidance and control. Therefore this paper consider an antitank guided missile system which belongs to the second generation for the design and analysis. Transfer functions representing the missile dynamics in pitch and yaw planes are derived to be considered for investigation. This investigation includes autopilot design and evaluating the system response such that the performance requirements are achieved. The control loop for both pitch and yaw channels of the intended guided missile system with compensation network are designed and investigated for each channel such that the system is stabilized and the performance requirements are satisfied. In addition, an inner loop design is carried out using free gyroscope for the yaw channel to improve its performance against target maneuver. To stay on the robustness of these compensators and their ability to withstand against disturbances, the measurements are corrupted with noise and the system performance is investigated. This investigation leads to the necessary modification or retuning the designed compensators for achieving the required robustness margin.

Linearization of Anti-Tank Guided Missile

“…This mathematical model is a set of differential equations that describe the missile motion. The block diagram of both yaw and pitch planes represented as set of transfer functions are shown in figure 8 and figure 9 [14].…”

“…The sensor and error detectors measure the missile error angle in pitch from the electronic bore sight using the day sight and the night sight as shown in figure 8 and figure 9. In some cases this angular error sensed by the guidance algorithm is weighted average of the two trackers and for the analysis of the two channels [14].…”

“…In pitch channel, the output of the compensation network is summed a time varying gravity bias function to produce the missile control surface command. In yaw channel, the filter output is summed with the azimuth tachometer input and a time varying open loop steering function [14].…”

“…The purpose of this limit functions is twofold. First, the commanded missile angle of attack must not exceed the structural capabilities of the airframe, and second to ensure that the command signal must be below levels at which excessive coupling between the steering loops and the roll channel could occur [14].…”

“…The motivation of linearizing the missile model is that it is a must to design a mature controller capable of dealing with maneuvering targets. The controller should be mature enough to deal with all flight conditions [14]. In the first section the coordinate systems and the total forces and moment acting on the missile are presented as well.…”