The Design & Realization Of UAV Autopilot System Based On LPC1758 Processor

Compared with traditional aircrafts, unmanned aerial vehicles(UAV)have advantages of small sizes, high flexibility, low cost, etc., which have been widely used in many fields. The autopilot as a core part of the UAV, whether the performance is excellent, directly determines whether the UAV can fly more stable and more reliable. Therefore, the study of UAV autopilot has important application value.In this thesis, based on LPC1758 processor, I design and implement a set of UAV autopilot system. The main work includes:the overall program planning and design, hardware circuit design and implementation, software program planning, the underlying driver design and system testing and analysis. The details are as follows:(1) By studying the principle of UAV flight and analyzing the functional requirements of autopilot, the design of UAV autopilot is completed based on LPC1758 processor, which includes global positioning system (GPS), sensor module with various types and functions, aircraft control module, multi-type serial communication module and the design of part hybrid power module. Compared with the existing autopilot hardware platform, the program has the advantages of smaller size and lower power consumption.(2) According to the hardware requirements of the above plan, the minimum circuit system for LPC1758 processor is designed and developed, including:external clock circuit with a high-precision active crystal oscillator, the professional reset chip reset circuit to improve system reliability, the simulation circuit with drive devices to ensure a reliable processor. On this basis, further design and development of the following circuits:including switching power supply, linear power supply and other types of composite power supply circuit, a variety of analog-digital sensor module circuit, high-precision low-power analog-digital conversion (AD) acquisition circuit, pulse width modulation (PWM) output circuit for controlling aircraft servos and motors, and serial communication circuits with various interface types.(3) According to the principle of UAV, the software architecture of the autopilot is designed and the hardware driver software is developed, including system initialization module drivers with functions of the system clock configuration, the processor pin function configuration and event interrupt configuration, time module driver with precise time stamp function, data acquisition module driver for collecting various analog and digital sensor data functions, PWM control module driver for controlling the movement function of various servo mechanism of airplane, and other underlying driver of devices to send and receive data with communication module driver functions.(4) The feasibility of the autopilot system is verified by testing the hardware module and driver module of the autopilot. Compared with the existing autopilot, the autopilot designed in this thesis is smaller in size, lower in power consumption and higher in accuracy, which can meet the design requirement of the system. It lays a foundation for the following design of the navigation and control algorithm.