Minimum-Time Turns of Aircraft by Feedback Guidance and Control Law

Abstract

This paper proposes two design methodologies for feedback controllers which generate the optimal pathes for the given criterion, for example minimum time, maximum range, minimum fuel and so on. The controllers discussed in this paper include not only guidance laws, but also control laws. Since a large amount of calculation is necessary to solve optimal path problems, it has been difficult to calculate them by onboard computers. The proposed path controllers give inputs using state feedback laws with time-invariant feedback gains. The proposed guidance and control laws does not need much calculation load, therefore they can be used for online controllers. Two types of feedback controllers are proposed in this paper. One uses feedforward inputs given as a function of a state variable, and the other consists of only state feedback inputs. Both controller are designed to minimize the given criterion for uncertain initial conditions. Although the first one has better performance, the second one needs fewer calculation load. Minimum-time turn of aircraft problems are solved as the application. The results show that the pathes which are generated by the proposed controllers are similar to the optimal pathes. The increment in the criterion is less than 1% of the optimal one. The proposed guidance and control laws are effective for online optimal path controller of aircrafts.