Automated Guided Vehicle Control

Small Unmanned Aircraft Vehicles(SUAVs)are widely employed for a board range of civil and military applications.To extend further applications,it is required to design a robust flight guidance and control system capable of autonomously guiding the vehicle to follow a predetermined path.However,SUAVs models are characterized by highly nonlinear behavior,strong coupling between longitudinal and lateral motions,and highly sensitive to the external disturbances and the model parametric uncertainties which dramatically increase the autonomous guidance challenges.The objectives of this research are to design and analyze a robust flight guidance and control system for fixed-wing UAV against uncertainties and disturbances.Three different flight control techniques are designed and analyzed with verification through simulations.Moreover,the outer guidance loop designed to generate the desired guidance command in responding to the desired path.Toward this objective,an integrated waypoints guidance scheme based on three distinct path following algorithms are designed and augmented with the designed inner loop flight controller to follow the desired path with accepted performance.The designed flight guidance and control system is validated using HIL simulations.The main work and contributions in this dissertation are outlined as follows:1.The main shortage of the NDI controller is the dependency of the accuracy of the simulation model,however,the precise models may not be available.To increase the system robustness,the incremental control action is applied using the body angular acceleration feedback which reduces the model dependency.Moreover,the asymptotic stability of the designed flight control system is improved to obtain a stable first-order differential equation of the tracking error.Furthermore,the selection of the decaying gain is optimized by using a numerical optimization algorithm to ensure and satisfy the smallest error.The simulation results demonstrate the robustness of the modified incremental NDI against model uncertainties.Moreover,the HIL simulations pointing out to the capability of adopting it as a promising practical flight controller.2.Backstepping(BKS)is partly a model-dependent controller and sensitive to high model uncertainties next to losing the generality of the designed flight control law.To improve the system response and robustness without losing generality,a robust adaptive flight controller is designed with completely model-independent control law which guarantees system robustness against high uncertainties and ensures the best tracking performance depending on the adaptive control action.The designed robust adaptive controller based on BKS is a sensor-based controller which depending on the accuracy of the navigation states.Therefore,a Kalman filter is designed to predict the unobserved states with high accuracy and negligible time-delay.The proposed generic robust adaptive flight controller proved to the best sensor-based controller through numerical simulation analysis.The most prominent advantage of adopting the designed controller appears with the HIL simulations obtained results without any further tuning.3.The proposed modification of the PID controller based on adopting the angular rates measured by the angular gyroscopes as negative feedback instead of differentiating the desired step reference.The practical enhancement ensured from this modification due to the validity of the IMU sensor to provide the required feedback.Moreover,the anti-windup mitigation introduced by preventing background integration while saturation.The numerical simulation results confirm the reduction of the control effort using the proposed modifications.Moreover,the HIL simulation results pointing out to the performance enhancement on the modified PI-D controller.4.Three path following algorithms are carried out for evaluation of the designed flight controller.1)The Carrot Chasing(CC)path following guidance law is a geometrically based guidance law,a Virtual Track Point(VTP)sliding on the path introduced to let the UAV chase the path.The advantage of the CC path following guidance law is the simplicity of implementation.In contrast,the poor robustness of the guidance law forced to augment it with a robust flight controller.2)The Pure Pursuit and Line of Sight-based path following(PLOS)guidance law is a geometric based path following with the combination of both guidance laws.The pure pursuit guidance law guides the UAV to the next waypoint,while the LOS guidance law steers the vehicle toward the LOS.The advantage of PLOS is the associated small crosstrack error.In contrast,it is not robust against high wind.3)The Nonlinear Guidance law(NLGL)is designed based on the Lyapunov stability theorem to ensure system robustness.NLGL depends on the concept of VTP tracking through assuming a circle intersected with the LOS connecting the two desired waypoints.NLGL proved through the simulation analysis to be the optimal guidance law in the existence of wind.5.HIL simulation is the bridge between pure simulation analysis and real-time practical application.HIL simulation is constructed using the XPC target computer as real-time processing connected to the host computer and the embedded microcontroller through TCP/IP connection and RS232 serial communication respectively.The host computer used to build and upload the designed flight simulation model to the XPC target,meanwhile the designed flight control system is implemented within the microcontroller.The HIL simulations figuring out the possibility to design a stand-alone flight guidance and control system and strengthen the simulation analysis.