Design and implementation of control for unmanned air vehicle

Abstract

Extensive researches have been conducted in advanced guidance, navigation, and control to exploit the full potential of autonomous Unmanned Aerial Vehicles (UAV). The uses of autonomous vehicles, for a wide variety of applications, have been increasing during the latest decades due to their great potential in numerous military and civil implementations. This motivated ever-increasing attraction of designing UAV flight control systems to achieve robust stability and acceptable performance across specified flight envelopes. The research in this thesis concerns the UAV, via three major constituents; the first includes development of a physical, inertial, and aerodynamic model representing the Ultrastick-25e UAV. The second is the development and implementation of a non-linear, six degree of freedom simulation, employing the developed model integrated with sensors and actuators constructed in Matlab/SIMULINK. The simulation enables control system design and pre-flight analysis throughout the entire flight envelope. Detailed post-flight analysis is also performed in Matlab/SIMULINK. The third constituent of the research includes the flight control system design. Developing an autonomous UAV control system is a challenge for several reasons; first, UAVs are highly sensitive to control inputs and require high frequency feedback with minimum delay for stability. Second, UAV dynamics are unstable, multivariable, highly coupled, and vary across the flight envelope. Third, UAVs have limited on-board power and payload capacity, due to which flight control systems must be compact, efficient, and light weight for effective on-board integration. The goal of this dissertation is to build an UAV mathematical simulation model and to design a control system that should be able to stabilize and control the underlying UAV. Simulation results are given to demonstrate that this nonlinear model behaves like the real UAV dynamic system. Trimming the nonlinear model for steady-state flight and extracting the linearized model for the UAV are performed using Matlab functions. The flight control system is designed using two different III techniques; the classical PID and the fuzzy logic control, and a comparison is performed between their performances. Simulation results showed that the PID controller handled the disturbances in a satisfactory manner but with some shortcomings. Therefore, it was desired to design a more advanced control strategy able to neutralize the shortcomings of the PID controller and to enhance its performance. Hardware implementation environment with experimental test results, when the aircraft disturbed by external force the autopilot reject it by position control on the elevator control surface, and from the analysis we have two result that determine the comparison between the attitudes with and without filtering pitch estimation comparison and roll estimation comparison. Keywords: unmanned air vehicle, ID control ,FUZZY control, equation of motion