Robust nonlinear LASSO control: A new approach for autonomous trajectory tracking

Unmanned Aerial Vehicle (UAV) technology has recently evolved to the point where autonomous execution of entire missions is possible. Advanced autonomous vehicles require new robust flight control systems that can achieve high accuracy while tracking aggressive trajectories. This demands full utilisation of a vehicle's performance and control capabilities over its entire operational envelope. This paper presents a new approach for trajectory tracking that takes full advantage of the vehicle's maximum capability. The approach, called "Robust Nonlinear Leap- Ahead Single-Step Optimal (LASSO) Control" is based on the stepwise solution of a constrained optimisation problem. The controller comprises a combined feedforward/feedback loop structure, which calculates the optimal vehicle states and controls to minimise the error between actual and desired vehicle accelerations as commanded by a stabilising guidance law. The solution extracts the maximum vehicle performance capability while accounting for dynamic and performance constraints, and the presence of bounded parametric uncertainty and external disturbances. Successful high-performance manoeuvre tracking is demonstrated using a detailed nonlinear simulation of a representative UAV. The control system exhibits excellent performance during the tracking of a challenging trajectory in the presence of significant parametric uncertainty and external disturbances in the form of wind gusts. 2003 by D.P.Boyle and G.E.Chamitoff.

Robust nonlinear LASSO control: A new approach for autonomous trajectory tracking Conference Paper