Flight Control System Design For Small Fixed-wing UAV Based On μC/OS-Ⅱ

Compared with conventional UAV, small fixed-wing UAV has some advantages, including low cost, light weight, small size, easy operation, etc. Flight control system is the core part of the small UAVs, exactly as UAV’s "brain." UAV flight control system operated according to a predetermined route flight, complete the objectives and tasks. Flight control system research is the key-point of Small UAV technology.According to the features of the small fixed-wing UAV, this thesis focus on research and design a low-cost, light-weight, highly integration flight system for small fixed-wing UAV. The target of the thesis is to supply a stable flight platform to research advanced flight control algorithm. The research focus of this thesis is as follows:1. Design attitude estimation based-on Complementary filter. The output of attitude estimation is the Euler angles, it provides the required information for flight control law. According to the characteristics of embedded microprocessors with limited computing power, this thesis uses a complementary filter on fusion of gyroscope, accelerometer, magnetometer signal, to achieve stable output UAV attitude information.2. Design the hardware platform of flight system. The hardware platform based on ARM microcontroller, MEMS inertial sensors to reduce power consumption and cost. At power section, digital devices and analog devices are powered separately to reduce signals interference.3. Design the software platform of flight system based on real-time operating system μC/OS-Ⅱ. Real-time is an important indicator of flight control system. This thesis design the software platform of flight system based on real-time operating system μC/OS-Ⅱ, simplifies the design of flight control applications, while real-time systems is guaranteed, the system is more robust, reliable and efficient.4. Design flight control tasks based on Control Mode. In this paper, divided flight control into several Control Modes, simplified the system control logic, reducing the difficulty of the task to achieve.In this paper, design of flight control system, in terms of hardware, meet the requirements of low cost, small size, high integration; in terms of software, to verify the correctness of the system design, this paper has conducted the integrated test, the results show that the system real-time performance is good, the flight mode, the control mode design is correct.