Automatic Control System Design For A Small Quadrotor Helicopter

The main purpose of this paper is to design a complete automatic control system for a quadrotor helicopter. The system includes not only the design of the control algorithm, but also realize the hardware platforms with sensors, control board and other related components. In order to have a full understanding of the quadrotors to provide the necessary theoretical basis for the design of the control system, this paper reviews the development of the quadrotors, and analyzes the research status and related outcomes of both at home and abroad.Then based on the coordinate systems defined, the attitude dynamics mathematical model and the position dynamics mathematical model are established using Newtonian mechanics. Due to the high coupling of the attitude, it’s not easy to design the attitude controller. Therefore, some basic assumptions are presented combined with the actual flight conditions, and the attitude dynamics mathematical model is simplified by using these assumptions. Then, a simple and reliable PD controller is designed for the simplified attitude dynamics mathematical model. Considering the error from the model simplifying and external disturbance on the system, a PD and CMAC(Cerebellar Model Articulation Controller) hybrid controller is designed to improve the robustness of the control system. The hybrid attitude controller is easy to calculate and to implement. In the premise of the stable attitude controller, the horizontal position controller and the altitude controller are designed respectively. In order to overcome the under-actuated problem of the horizontal position control, two virtual control quantities are created, which changes the under-actuated system to be controllable.In order to complete the design of the whole system, there have a detailed description of the experimental platform. Especially the very important two parts of sensor system and control board, whose performance, parameters and functional interfaces are descripted more deeply. On the basis of the experiment platform, this paper also has a detailed explanation on the key technologies about the data acquisition, position conversion, position data fusion, and the translation of the PWM signals. Finally, the result of the analysis and comparison of the experimental data verifies the stability and reliability of the quadrotor automatic control system.