Fuzzy Sets and Systems 146 (2004) 313–347 www.elsevier.com/locate/fss A fuzzy ight controller combining linguistic and model-based fuzzy control B. Kadmiry a ; ∗ , D. Driankov b a Department of Computer and Information Science (AIICS), Link oping University, F490, 581 83 Link oping, Sweden b Department of Technology (AASS),  Orebro University, Sweden Received 24 January 2001; received in revised form 21 October 2002; accepted 18 July 2003 Abstract In this paper, we address the design of a fuzzy ight controller that achieves stable and robust “aggressive” maneuverability for an unmanned helicopter. The fuzzy ight controller proposed consists of a combination of a fuzzy gain scheduler and linguistic (Mamdani-type) controller. The fuzzy gain scheduler is used for stable and robust altitude, roll, pitch, and yaw control. The linguistic controller is used to compute the inputs to the fuzzy gain scheduler, i.e., desired values for roll, pitch, and yaw at given desired altitude and horizontal velocities. The ight controller is obtained and tested in simulation using a realistic nonlinear MIMO model of a real unmanned helicopter platform, the APID-MK3. c  2003 Elsevier B.V. All rights reserved. Keywords: Unmanned helicopter; Takagi–Sugeno fuzzy control; Fuzzy gain scheduling; Linguistic modeling and control 1. Introduction The central problem addressed in this paper is the design of a ight controller that achieves sta- ble and robust “aggressive” maneuverability for an unmanned helicopter. Thus, the ight controller described here executes, in a stable and robust manner: (i) tracking of trajectories describing curvi- linear translational (or horizontal) motion at relatively high speed, and (ii) set-point regulation for fast acceleration= deceleration, hovering and climb. The robustness of the ight controller is dened as its ability to compensate for: (i) external disturbances in terms of wind gusts, (ii) model parameter uncertainties in terms of changing payload, and (iii) sensor noise for attitude control signals. * Corresponding author. Tel.: +46-13-284-493; fax: +46-13-285-868. E-mail addresses: bouka@ida.liu.se (B. Kadmiry), dimiter.driankov@tech.oru.se (D. Driankov). 0165-0114/$ - see front matter c  2003 Elsevier B.V. All rights reserved. doi:10.1016/j.fss.2003.07.002