Compliant Formation Control of a Multi-Vehicle System

Abstract

This research identifies a strategy called compliant formation control, which may be used to coordinate the navigational structure of a team of autonomous vehicles. This technique controls the team's motion based on a given, desired formation shape and a given, desired set of neighboring separation distances, wherein the formation shape is considered general two-dimensional. The strategy establishes how to select, place, and use virtual springs and dampers that conceptually "force" proper interspacing between neighboring team members. The objective is to continuously maintain, in the most optimal way, the desired formation as team motion proceeds. In practice, actual robot separation distances will be measured relative to smarter, leader robots that have known position and orientation information at all times (e.g., GPS or INS). The control strategy subsequently commands, in an optimal way, each vehicle by providing a heading and velocity necessary to maintain the desired formation. Such requisite commands result from modeling the compliant displacements of team members as they travel in a network of virtual springs and dampers. The equations used to achieve coordinated motion of the robot team will be discussed and specific case studies will be presented to demonstrate the effectiveness of the compliant formation control strategy.