Actuator controller based on fuzzy sliding mode control of tilt rotor unmanned aerial vehicle

The Smart Unmanned Aerial Vehicle (SUAV) is the tilt rotor type aircraft, which has been developed by the Korea Aerospace Research Institute (KARI). The actuation system of the SUAV is composed of actuators, controllers, and mechanical linkages for the control elements, i.e. nacelle tilt, flaperon, elevator, and rotor. It should be able to control the vehicle under a variety of aerodynamic loads while the control performance is fulfilled in terms of accuracy, response time, and stability. In order to satisfy the target performance, the system employs the sliding mode control that guarantees stability under varying loads. In addition, the system is enhanced with the fuzzy control logic that enables intelligent selection of the control switch. Based on this fuzzy sliding mode control (FSMC) scheme, the actuator controller of the SUAV receives the control commands from the Digital Flight Control Computer (DFCC) and transmits them to actuators under the feedback control logic. This paper presents the application of the FSMC to the SUAV and provides the description of the actuation system architectures, modeling and analysis for the actuation system, implementation of the control logic into the actuator controller, and verification of the actuator control system through ground and flight tests of the SUAV.