Performance evaluation of two linear controllers for heading control of a UAV

Abstract

In recent years, Unmanned Aerial Vehicles (UAVs) have become very popular in civil and defense sectors. Due to their numerous applications, the UAV industry is flourishing with great pace. An autopilot having the complete flight control system is the heart of a UAV. It is an onboard system which controls and navigates the in-flight UAV autonomously. These days, multiple commercial solutions for UAV autopilot are available in the market. In these commercially off the shelf (COTS) solutions, mostly ailerons are used as the input control surface. PID (Proportional-integral-derivative) based heading controllers are generally used for steering the UAV in the desired direction. In our work, performance evaluation of two different heading-controllers is carried out. In both the schemes, aileron deflection acts as the input variable for the feedback and control mechanism. One of the controllers uses PID based controller while the other one makes use of phaselag based heading controller. First step in the controller design process includes selection of a nonlinear UAV model, which is linearized at steady state trim conditions. The next step includes design of linear PID and phase-lag controllers and their subsequent application on nonlinear model. Finally, the effectiveness of deigned controllers is gauged by comparing the simulation results of compensated linear and nonlinear models. Our investigation clearly proves that PID-based heading controllers are a better choice, as these have better transient and steady-state response as compared to Phase-lag controllers.