Indoor autonomous hovering control for a small unmanned coaxial helicopter

For the nonlinear and open-loop unstable characteristics of the small helicopter, autonomous flight control is a challenging problem. In order to reduce the complexity of the helicopter autonomous control, this paper constructs an indoor autonomous flight control platform for a small coaxial helicopter ESky LAMA4, which is convenient for data collection, data analysis and control law design. Firstly, the Vicon Mx Motion Capture System is installed to obtain the attitudes and positions of the coaxial helicopter. Secondly, a PCTx converter for the radio controller is used to convert the control commands into PPM signals which are sent into the radio controller. Hence the attitude and translational motion can be controlled. Then in the inner attitude loop and outer translational loop, several PID controllers are designed for the autonomous hovering control of the small coaxial helicopter. Finally the flight results demonstrate the feasibility of the proposed approach, which can be adopted into the study of small unmanned helicopters in the future.