Finding trim points of the ICE model using interval analysis

Abstract

In this work interval analysis is applied to the thirteen control effector Innovative Control Effectors model to find its trim set. The method to find trim states is based on interval box consistency. At low speed the method is capable of finding interval enclosures of single trim points with a high accuracy if the minimum number of required control effectors is used. At higher speeds the found accelerations are larger. When looking for a full trim set the method finds continuous bounds on the control effectors for the entire input range in one run. This is a good demonstration of the advantages that interval analysis has over conventional methods that generally can only find one trim point at a time. The found bounds are a maximum of 1 deg wide for each control effector, but despite this the remaining accelerations can be up to 0.5 m/s^2 for linear accelerations and up to 10 deg/s^2 for rotational accelerations. Because of these large accelerations the found solutions are not acceptable as trim conditions. On the other hand the potential that interval analysis has as a trimming method is demonstrated, since continuous bounds on trim sets have been found in a single run. This is a feat that no other trimming method has yet accomplished. Further research is needed to exploit the full potential of interval trim methods so that the results can be used for other purposes such as flight envelope prediction.