| This research identifies a new 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.; Research in multiple vehicle systems has addressed follow-the-leader techniques, cooperative mapping, reconnaissance and communication, and learning and adaptation techniques. Each of these areas is interested in multiple vehicle coordination techniques. However, formation control may or may not be a concern, as the following contemplates. For example, follow-the-leader techniques, as the name implies, require formation control while cooperative mapping is mainly concerned with maximizing coverage area and development of a world model. Multiple vehicle reconnaissance heavily depends upon communication between team members and robotic relays have been developed to alleviate the communication limitations. Learning and adaptation applied to systems of robots draws upon biology to create behaviors that react to environmental stimulus. Behaviors such as foraging and flocking provide a form of loose formation control as dictated by nature. The techniques mentioned above have merit in the realm of multiple vehicle research but lack a clearly defined technique for strict formation control.; This research provides a strategy for formation control that is based on a desired formation shape. 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. One of the primary contributions of this work is the development of a methodology to determine the internal behaviors for the individual mobile robots in order to achieve a desired global formation for the entire system. One of the motivations here is to reduce the cost and increase the navigational effectiveness of a team of mobile robots, since only a select few team members (leaders) are required to be equipped with expensive GPS or INS equipment. |
