Path Elongation for UAV Task Assignment

Abstract : This paper presents a path planning and path-elongation method for wide area search munitions, a type of small Unmanned Air Vehicle. Variable-length paths are necessary to allow sufficient flexibility for efficient task assignment meeting timing constraints for UAVs. Five specific cases are developed that identify the best method of elongation based only on the initial position and heading of the vehicle with respect to the target. The cases include one linear direct method of path elongation and four cases which use an iterative approach for the nonlinear path elongation. The iterative methods are similar to a Newton-Raphson search over a function for a specific value (a path of the desired length). The function searched are the path length vs. the delay used, are monotonically increasing, and are very well behaved. The result is fast convergence to a small window around the desired value (path length). Multiple aspects of the path elongation program are presented. First, the problem setup is reviewed which includes the correction to the heading algorithm and the definition of the different cases and their associated elongation methods. The process of the iterative method is described and the results of the individual methods are presented. Results are shown for elongated paths for each of the five cases, and simulation results are shown using the path elongation algorithms in a task assignment problem.