The Autopilot Of Small UAV Designed Based On ARM

With the wide application of unmanned aerial vehicle(UAV) in the civil military and civilian areas, higher requirement of UAV overall performance is also put forward. The autopilot system is an important part of UAV and is the precondition of ensuring stability of UAV to complete the task. Therefore, the UAV autopilot system has a very important research value.In this paper, the composition and working principle of the UAV autopilot are summarized based on the full analysis of military and civilian UAV autopilot in domestic and foreign. Taking small UAV as the research object, the overall design scheme of the autopilot system is given. According to this scheme, the design of autopilot system hardware, the underlying driver software, and the control law software will be given out.The hardware-in-the-loop simulation environment is built based on the completed autopilot hardware platform. The performance of the autopilot is verified by the simulation analysis.Firstly, taking the STM32F103, which is the kernel of ARM Cortex-M3, as the core microcontroller, the hardware platform of autopilot is developed and designed. The hardware platform integrates minimum system circuit, serial communication circuit, CAN bus circuit, SD memory card circuit, network cable interface circuit, sensor circuit and power circuit. Among them, the sensor circuit includes the gyroscope, accelerometer sensor circuit, magnetic heading sensor circuit, pressure sensor circuit and GPS circuit. Such as design, welding and debugging of the hardware platform are completed.Secondly, we'll accomplish the underlying drivers' software design for the hardware programming based on the scheme for the hardware platform.The longitudinal control law and the lateral control law of small UAV are designed based on the PID control principle and the feedback control principle for micro-UAV on the basis of MATLAB/SIMULINK models. The application from genetic algorithm to the control law is proposed innovatively and the optimization of three PID parameters is completed. Through the closed-loop simulation in MATLAB, the correctness of the designed control law is analyzed and C codes are compiled to complete the design of control law software.Finally, the software of FlightGear is used as the visual scene, the network communication protocol software is written to set up the communication with the hardware platform of autopilot. The hardware-in-the-loop simulation environment is built and the design precision and reliability of the autopilot system are verified.“The higher efficiency and the lower cost” is the development principle all the time in this paper. A set of autopilot system with independent intellectual property rights is designed in order to lay a good foundation for future research.