Control system design and evaluation for robust autonomous rotorcraft guidance
Abstract This paper describes the design and performance analysis of a control system for rotorcraft with an emphasis on the requirements called for by autonomous guidance. To be able to track trajectories, such as those generated by a guidance system, a path following controller is used in combination with a velocity control augmentation. The path following system is motivated by nonlinear stability analysis. The velocity control augmentation follows a loop shaping design for the inner loop attitude control and a dynamic inversion velocity control design for the outer loop. The identified model of the dynamics along with the uncertainties is used to determine the robustness and performance of the velocity control system. Finally, the paper presents a novel method to evaluate the overall performance of the control system in terms of the tracking error statistics. These results are then used to determine a tracking error model, which can be used to predict the tracking error for a given reference.