Robot Teams and Robot Team Players

Abstract

Multi-robot systems are generally organized around the concept of a team, from teams of mobile robots for outdoor tasks such as surveillance to teams of smaller robot systems for competitions such as RoboCup (Balch & Parker, 2002; Schultz & Parker, 2002). Variants of this theme include small numbers of cooperating robots for transport tasks, such as two robots carrying an extended payload, which is the robot equivalent of a two-man team. In the majority of research the team structure is limited to a single team. In this chapter, we propose to explore a multi-team model for multi-robot systems, whereby multiple subsets of robots are drawn from a larger pool to form multiple teams. Each team has an assigned task that is to be distributed among the members of the team. In the conventional model for robot teams, a task is broken into sub-tasks and each sub-task is allocated to members of the team through a negotiation process; individual robots can signup for one or more sub-tasks based on their ability to perform the sub-tasks. The set of robots which sign-up are essentially the team associated with the task. A limitation of this model is that it doesn’t support the concept of multiple teams of robots, in which each team has a collective identity associated with a task it is to perform that is separate from the identity of other teams. However, multiple teams are a successful approach used in business and industry to organize work (Jelphs & Dickinson, 2008). The benefit of multiple teams is that work can be carried out in parallel, improving efficiency. Further, it is possible to reallocate robots between teams, a practice often used in business and industry to ensure that tasks are completed on time. Introducing a multi-team framework in multi-robot systems can offer the same benefits. Moreover, in the conventional multi-robot team, robots can locally cooperate, effectively forming a sub-team. This is generally perceived as cooperation but not necessarily team based cooperation. However, the concept of forming and re-forming sub-teams may be useful in this context as well. Therefore, a model emerges in which a pool of robots provides a resource for creating multiple teams, each of which essentially can be seen as a pool of resources in its own right for creating further sub-teams when needed. The chapter is organised as follows. The following section outlines the requirements for multiple robots working in multiple teams. The third section of the chapter proposes a model for multiple robots working in multiple teams, which we abbreviate as the MRMT model.The fourth section discusses the architecture in more detail, specifically the concepts of roles and targets and the communication requirements. The fifth section provides two case studies, motivated by space applications, to describe how the model can work in practice. The final section provides a summary and conclusions.