Automatic flight control of unmanned conventional tailrotored helicopter

In recent years, simple fixed-wing unmanned aerial vehicle systems have attracted all the attention with their game-changing role on the battlefields. This has led to discussions of taking into service of cheapest, simplest, and lightest helicopter platforms, which are designed in the rotary wings' world for some substantial missions such as reconnaissance, surveillance, and military special courier transport. In this context, this study aims to develop a helicopter flight control system in MATLAB & SIMULINK environment for a conventional tail-rotored rotary wing unmanned aerial vehicle (RUAV) concept to enable automatic flight, landing and take-off. The model was built to simulate a general-purpose helicopter without stabilizer bar and was preferred as the helicopter mathematical model for simulators for years in historical helicopter development literature. This mathematical model, which is inherently nonlinear, is linearized according to the input and output channels by using the linear analysis tool. Thus, controllers are developed to fit this linear model. At the end of the study, it is aimed that, the hover flight, forward flight, landing and take-off according to trim points can be achieved automatically for different altitudes. In the flight control system, firstly, a controller for stability augmentation is designed by establishing internal stability. Then, it is aimed to keep the helicopter to desired speed, altitude, orientation, and position by establishing an attitude-hold external stability loop. It is observed that the model is inherently flying by sliding to far left-hand side (west). After that, the performance of the controllers is examined according to keep the model into the ideal route by adjusting control command inputs for each trim points. Finally, optimum controller gains are found to improve controller performances. P, PI and PID as classical control methods are used within these loops.