The Research On Relaxed Directional Static Stability Of Unmanned Aerial Vehicle

Unmanned Aerial Vehicle (UAV) is one of the most important tactics powers.In this paper, relaxed directional static stability is studied based on a certain Chinese UAV in order to do some preparative work for high-powered UAV.Firstly,a mathematic model of relaxed static stability(RSS) UAV is built,taking the certain UAV as an object.The motion of the UAV is expressed in 12 first-order,coupled ordinary differential equations which is six-degrees-of-freedom(6-DOF) rigid model. Then follows the concept of directional static stability, the effects of relaxed directional static stability on UAV's directional parameters,and the argumentation of the dynamic characteristics of RSS UAV. Lastly, the paper gives several compensation ways of directional static stability.Linear quadratic (LQ) theory, one of the multivariable control technology of modern control theory, is also studied.At first, we introduce the LQ Regulator (LQR), LQ Tracker(LQT) and LQ Guassian/Loop-Transfer Recovery(LTR) in detail.Then the theories are used into the design of flight control system.It gets good results.In the following paper, Genetic Algorithms(GA) is described to optimize LQ technology.In the end of the paper, the LQT based on GA is applied to design the flight control system of RSS UAVs.The intensive simulation verified the validity of our research.All the research concludes that relaxed directional static stability UAVs is realizable.