Research On Control Algorithm Of Small Unnmanned Aircraft In Automatic Flying

Unmanned aerial vehicles(UAVs), large and small, have demonstrated their usefulness in military applications. Furthermore, there are numerous potential uses for UAVs in civil and commercial applications and the prospects for broad impact are strong. To extend the usefulness of UAVs beyond their current applications, the capability to plan paths and to follow them precisely is of great importance. This article research on the unmanned aircraft vehicles’ path following problems, especially deal with the control and guidance problem. The research about this article include the following aspects:Firstly, in order to simplify the research, an integral mathematical model of small fixed-wing UAVs has been gave. Including the definition of the coordinate system, establish the dynamics and kinematics equations, especially taking into account the small UAV air disturbance, because of wind disturbances limit the achievable tracking precision, wind interference model is introduced.Secondly, based on the nonlinear mathematical model of fixed-wing UAV, inner-loop attitude controller has been designed. Taking into account the vulnerability of small fixed-wing UAV disturbance characteristics, control method uses gain scheduling control strategy. In order to design the gain scheduling control, the equations of motion to produce reduced-order transfer function has been linearized and decoupled, low-level autopilot control loops for unmanned aircraft has be designed.Thirdly, the outer-loops into the longitudinal channel, lateral channel and airspeed channel has been separated from the integral. The longitudinal autopilot is more complicated than the lateral autopilot because airspeed plays a significant role in the longitudinal dynamics. Our objective in designing the longitudinal autopilot will be to regulate airspeed and altitude using the throttle and the elevator as actuators. Heading channel as a significant part in the UAV’s mission, we designed gain scheduling control strategy. Taking into account the i mpact of air disturbance on the MAV path following problem, we present the vector field guidance as a method which is different from the traditional method. Because of the Dubins path is made of straight line and orbit path, we designed straight path follo wing and orbit path following strategy using vector field guidance.Finally, we designed hardware-in-loop real-time simulation platform. The platform composed of the PC / 104 and industrial control computer. Real-time and hardware-in-loop simulation platform, data communication technology and multi-thread technology have been researched. All the algorithms which designed above has been tested. The simulation results show that the design of the controller in the disturbances have good control effect, designed vector field guidance in wind situation tracking the Dubins path precisely.