The Design Of Autopilot For Bank-to-Turn Missile Based On Adaptive Neural Networks

Bank-to-Turn (BTT) missiles have arosen increasing attention since its coming into being. This is due to the fact that the normal over-loading vector of this missile can always be located at the missile's maximum lifting surface. Hence BTT missiles feature superior maneurability to Skid-to-Turn (STT). However, BTT surfers strong coupling in the pitch and yaw motions, which exhibits highly nonlinearity in the control system. Thus the traditional design methodology of STT missiles'autopilots, which treats the three loops independently, proves to be non-sufficient to BTT ones. This brings great challenge to the designing of BTT missile's autopilot.To solve this problem, this thesis integrates adaptive neural network and H-infinity control theory to design BTT missile's autopilot. This method has overcome the shortcomings of the traditional design methods. It needs no piecewise switching to control the BTT missile to realize the performance specification. The main contents of this thesis are as following:Firstly, the mathematical model of BTT missiles is established. Since this model is a highly-coupled, non-linear, time-varying and non-minimum phase system, input-output linearization is used to do some preprocessing work. Meanwhile, since that methodology can not be applied to non-minimum phase system, BTT missiles'outputs are re-formulated.Then a neural network is employed to approximate the non-linear component of the input-output linearized system. This network is a ridge Gaussian one, which is preferred because of its good approximating capability and less online tuning weights. As for its architecture, it is simply an extention of Gaussian radian basis function. Thus theoretically this network can approximate any nonlinear system with any precision.However, since the approximating error is almost always present, H-infinity theory is refered here to design a controller to guarantee the performance of the whole control system.Furthermore, some simulations are conducted with the mathematical models aforementioned. These simulations aim to reveal the BTT control system's...