Robust Path-following Control with Anti-Windup for HALE Aircraft

Abstract

In this paper, a robust path-tracking controller for a High Altitude Long Endurance (HALE) aircraft is presented. The main control paradigm for operating a HALE aircraft consists of a basic path following control, i.e. tracking a reference flight path and airspeed while dealing with very limited thrust. The priority lies in keeping airspeed inside the small flight envelope of HALE aircraft even during saturated thrust. For the basic path following objective, a mixed sensitivity approach is proposed which can easily deal with decoupled tracking and robustness requirements. To deal with saturated control inputs, an anti-windup scheme is incorporated in the control design. A novel observer-based mixed sensitivity design is used which allows directly using classical anti-windup methods based on back-calculation. The control design is verified in nonlinear simulation and compared to a classical total energy control based controller.

Attitude Control for High Altitude Long Endurance Aircraft Considering Structural Load Limits

“…This paper uses the DLR's HAP platform [3] as an example with its initial control designs [4][5][6]. An artistic representation of the DLR HALE platform is shown in Fig.…”

Robust Path-Following Control for High-Altitude Long-Endurance Aircraft

“…The observer-based design has the advantage that including anti-windup becomes a fairly straightforward task. The design follows an approach presented in [1,2]. The resulting flight path-tracker is connected to an inner cascade consisting of an attitude controller introduced in [3].…”