Flight Control Law Design Of Coaxial Unmanned Helicopter

In recent years, with the development of agricultural technology innovation, green agriculture and precision agriculture technology has developed rapidly. Application of agricultural aviation technology has been more and more taken seriously by people. However, in term of agricultural spraying operations, fixed wing aircraft is usually droved. Fixed wing aircraft has m any limitations in the spraying operations. For instance, fixed wing aircraft speed in spraying operations should exceed stall speed. Also, flight safety of the spraying height should not be too low and fixed wing aircraft requires special runway. Considering above factors, helicopters are more suitable for the spraying operation. Compared with the traditional helicopter, coaxial helicopter has the characteristics with large load, small power consumption in hover and high stability. It is suitable for agricultural spraying task with large load and low speed flight. With rapid development of computer technology, aviation aircraft operations is developing toward the direction of unmanned. Therefore, coaxial unmanned helicopter was used as the experimental plat form. flight control theory was used as the foundation. The coaxial unmanned helicopter mathematical model was established and flight control law was designed.Firstly, coaxial helicopter modeling was handled with theoretical derivation. When rotor wing was modeled, twin rotor aerodynamic interference factor was joined and coaxial unmanned helicopter full nonlinear model was deduced by rigid body kinematics equation. At the same time,The linear mathematical model of coaxial unmanned helicopter was establ ished with small perturbation theory. Then, Newton iterative method was used to balance the linear mathematical model, for flight control law is designed to prepare.Subsequently, coaxial unmanned helicopter equilibrium point was used as a reference. Coaxial unmanned helicopter flight control law design were described in detail in the aspect of longitudinal control, lateral control, height control and position control. Simulink was used to establish the control law simulation model. The design of a flight c ontrol law simulation was verified and adjusted.From all aspects of order jump response curve, control law parameters are selected appropriately and stable to control the coaxial unmanned helicopter. The designed control law has strong stability.At the end of the article,the simulation flight test by analyzing test data to further validate the flight control law design with good quality, it meet the basic requirements of flight and speed up the pace of unmanned coaxial helicopter in agricultural aviation applications.