Flight Control System Design And Implementation For Small Unmanned Helicopters Based On FPGA

The application of small unmanned helicopter is widespread. In military, it can be used to make a virtual target, surveying the enemy, attack the enemy and so on. In civilian, the using of it is mainly for high- voltage line maintenance, mapping and spraying pesticides. Therefore, the small unmanned helicopter attracts more and more attention in recent years. This paper adopts FPGA as the core control devices to research the small flight control system design and implementation issues. The followings are the manly works of the article:First, according the research status o f small unmanned helicopter flight control system design, the thesis analyzes the takeoff, hover and other status of the helicopter, and gives design program of small unmanned helicopter flight control system based on core control devices of FPGA.Second, the paper uses least squares method to fit flight data for control amount curve of draw height, pitch angle and roll angle, and adopts the critical point method of ZN curve to obtain PID parameter values for each channel. For the problem of small unmanned helicopter’s takeoff depended on ground control, it proposes a autonomy takeoff strategy of height and stance simultaneous control, reduced takeoff difficulty.Third, developing the overall hardware design adopt FPGA as core control device, including the smallest unit control panel, system power, program memory, data collection and so on. For the issue of servo vulnerable to external analog signal interference, it designs a separate power supply module, signal isolation module, independent manual switching module, and use data acquisition to achieve a real-time acquisition of flight data.Four, according to the development of the hardware program designs software correspondingly, including SPI, UART, I2 C communication interface with FPGA controller, FIFO data buffer, PWM signal encoder, PWM signal memory, and the steering control using PID algorithm. The article achieves the autonomy takeoff control of small unmanned helicopter, and uses Lab VIEW software for 3D dynamic real-time detection and display of small unmanned helicopter, and verifies the correctness and effectiveness of the control system design.