Structured Robust Control for Small UAV

Abstract

The performance and dynamic stability issues of flight control systems are still considered one of the most challenging design problems even though all of significant advances that have been happened in UAVs in the two last decades. This paper is devoted to design a flight control system to stabilize the attitude of small UAV against additive uncertainties. Toward this objective, structured robust control framework is considered. The design procedure is performed using two control configurations: The single degree of freedom (SDOF) controller is considered and then followed by the two degree of freedom (TDOF) controller to achieve some advantages. In SDOF configuration the entire set of all stabilizing controllers are, graphically, computed and then the controller parameter are, arbitrary, selected. A trade-off between designs requirements in SDOF controller determines the use of the TDOF controller. Therefore, the obtained parameters from SDOF controller are taken as initial guess and tuned using TDOF decentralized control to achieve the pre-determined performance specifications, while guarantee pre-determined robust stability. The obtained results clarify the ability of the designed controller to achieve an adequate level of stability and performance properties.

Keywords

• robust PI control
• structured controller
• 𝛨∞ control synthesis