# Engineering Challenges Ahead for Robot Teamwork in Dynamic Environments
## 2 Terminology  
Let us first briefly define the basic terminology used in this paper. A _robot_ is a programmable machine capable of carrying out a complex series of actions automatically (The Oxford English Dictionary, Oxford University Press). An autonomous robot is capable of perceiving its environment through sensors, reasoning about the gained information, making decisions accordingly, and acting upon its environment through actuators, all without human intervention. These capabilities are also commonly associated with the term _agent_, whereby agent is considered a more general term, i.e., a robot is a special kind of agent that (mostly) is realized as a mechatronic construct. A robot may adopt a certain _role_ based on its capabilities. It executes _tasks_ that are described in a _task plan_. For example, in an autonomous driving traffic scenario, an emergency vehicle has a role that is different from regular vehicles. It has specific capabilities and rights and executes different tasks than regular traffic participants. According to [PERSON] et al. [6], a _multi-robot system_ is a group of robots operating in the same environment. The authors point out that there are many different kinds of multi-robot systems. Their taxonomy is based on the two general dimensions _coordination_ and _system_. The coordination dimension is subdivided into _cooperation_ (do the robots cooperate to solve a problem? ), _knowledge_ (how much knowledge do the robots have about each other? ), _coordination_ (how much coordination is enforced? ), and _organization_ (what kind of decision structure does the multi-robot system employ?). The system dimension consists of _communication_ (what kind of communication mechanisms and protocols do the robots use? ), _team composition_ (are the robots homogeneous or heterogeneous? ), _system architecture_ (does the collective as a whole deliberately cope with an unanticipated problem or just the directly affected robots), and _team size_ (how scalable is the system in terms of number of robots?). For a more detailed discussion, we refer the reader to the original publication [6]. Specifically, our emphasis in this paper is on multi-robot systems consisting of autonomous robots that _collaborate_ in order to achieve a common _global goal_, perhaps in addition to their own local goals. We call such a collective of collaborating robots a _multi-robot team (MRT)_ or multi-robot coalition. In dynamic and unpredictable environments, roles and tasks are allocated dynamically to the members of an MRT according to their capabilities and current situation [10]. This allocation was formally modeled and analyzed as an optimization problem using various optimization techniques [11]. From a conceptual modeling perspective, an MRT is a multi-agent system that has a physical representation with specific properties determined by the mechatronic nature of the agents. The main focus of our own research is achieving adaptive goal-driven _teamwork_ in a group of autonomous robots. Thus, according to the taxonomies in [6; 12], we are concerned only with _cooperative_ MRTs, consisting of robots that are aware of their teammates. How cooperation and awareness are achieved may differ. Since teamwork is the main subject of this paper, we should briefly discuss the related terminology for characterizing the type of interaction that the robots employ to achieve teamwork. Here, we have to point out that, even with existing standards such as the Foundation for Intelligent Physical Agents (FIPA, [[http://www.fipa.org/](http://www.fipa.org/)]([http://www.fipa.org/](http://www.fipa.org/))), there is no common agreement on the definitions of these terms, i.e., different authors use different connotations. We refer to [PERSON] [13] who differentiates between four types of interaction styles as follows: