Development and Experimental Testing of Flight Path Control using Total Energy Control and SISO Control Loops

Abstract

Proportional-integral, single-input single-output (PI SISO) control is a common approach and therefore appealing for altitude and speed control loops. The aircraft dynamics of altitude and speed are inherently coupled. Total Energy Control System (TECS) architectures can overcome coupling between speed and altitude control. The influence of the control architecture on control effort and motor activity which possibly influence flight time and range, as well as the architectural influence on control performance is critical when selecting the architecture for longitudinal control. This paper contributes to the design, the evaluation and choice of a proper control architecture, comparing advantages and disadvantages of the two approaches. For an uncertain model of a remote controlled UAV glider aircraft, altitude and speed control are developed and analysed. A robust control method, using non-smooth H∞ design, is described for tuning both a fixed-structure TECS and a PI SISO controller architecture for altitude and speed control. The resulting controllers are based on the same criteria of loop shape and disturbance rejection and compared regarding their linear controller design, implementation and flight test performance on a UAV platform. Flight test data demonstrate the viability of the controller design approach. Performance indicators show reduced control effort for the TECS design without significant trade-offs in tracking.