Research On Technology For Unmanned Helicopter Modeling And Control System Design

This dissertation studies key technology of modeling and autonomous flight control for unmanned helicopter based on U8 unmanned helicopter which is developed by Nanjing University of Aeronautics and Astronautics and China Helicopter Research and Development Institute.Because of high-rank, unstability, nonlinear, strong coupling and high uncertainty of helicopter, it is difficult to build dynamic model of helicopter. This dissertation proposes idea of integrated modeling of helicopter based on three models, simple helicopter model based on moment theory, complex helicopter model based on blade element theory, and helicopter model based on FLIGHTLAB software, and applys the integrated model to project of unmanned helicopters. High credible model for request of control system design and simulations of unmanned helicopter is achieved by comparison and test of models, comparison and validation model with flight data. This dissertation analyses U8 unmanned helicopter based on validated blade element theory linear model.This dissertation studies explicit model-following control with inverse model feedforward, and H_∞loop-shaping control method, and an enhanced explicit model-following loop-shaping control method is proposed, the method has advantages of both explicit model-following and H_∞loop-shaping control methods. Attitude control system of unmanned helicopter is designed based on enhanced explicit model-following loop-shaping control method, and is analysed in time domain, frequency domain and robustness, and is compared with attitude control system which is designed by classic PID method, explicit model-following method, and H_∞loop-shaping method.The dissertation designed track flight and mode flight control system for unmanned helicopter, realized autonomous take-off, landing, hover and coordinate turn flight control. For test the flight control system, control logic and flight manange system, example path is designed, which is composed of four flypoints, and autonomous path flight control system is designed and simulated. The robustness of control system is tested by flight of U8 unmanned helicopter in example path with uncertainty and wind disturbation.This dissertation designed modeling, control and simulation system for small-power piston engine of example unmanned helicopter based on power performance and dynamics, and designed control stratedy by"dogleg"method based on the property of the engine in overrunning stage.The dissertation applied modeling and control technologies to U8 unmanned helicopter, and tested the technology by modeling, real-time simulations and research flight tests.