Research And Implementation Of Flight Control System For Small Scale Unmanned Helicopter

The research of small-scale unmanned aerial vehicle (UAV) helicopters gradually becomes more and more popular both in industrial and academic filed in recent years. The small-scale UAV helicopters are agile, controllable and can take-off and land vertically, hover, and cruise. Owing to these natural advantages, they are widely used in military and civil domains.The main purpose of this paper is to develop an autonomous flight control method for small-scale unmanned helicopter. In this paper, varieties of flight control algorithms are designed, and a large number of simulated and real flight experiments made to verify the proposed flight control methods. The main contributions of this paper are outlined as follows:(1) Mathematic modeling of small-scale unmanned helicopter: Based on the dynamic model proposed by researchers from Carnegie Mellon University, we designed our own 11th order mathematic model for TREX 450SE helicopter.(2) Based on the classic PID (Proportional-Integral-Derivative) method, autonomous flight control system was designed: A flight control system using the classic PID method is developed. The whole control system is separated into three loops, namely the inner loop attitude control, the middle loop velocity control and the outer loop position control. Simulation results show that with this control strategy, the UAV helicopter can autonomously take-off, landing, and hover.(3) Based on the dynamic inversion method, another autonomous flight control system was designed as well: According to the mathematic model, a flight control strategy is designed based on the dynamic inversion method. The simulation results indicate that compared to the PID method, this control strategy greatly improves the system's performance in terms of its response time, control precision and stability. Also, this control method has great adaption, which can be applicable to other UAV helicopters.(4) Designed and developed the flight control system in an onboard computer PC 104, with Linux operating system.(5) Perform real indoor flight experiments: The real indoor flight experiments show that the autonomous flight control system proposed in this paper is correct and effective.The achievement of this paper provides a vital foundation for the research and application of the small-scale unmanned helicopter. The flight control method proposed in this paper can successfully drive TREX 450SE helicopter to take-off, landing, and hover indoor, with excellent performance in control precision, stability, and response time.