Ronald C. Arkin

Behavior-based formation control for multirobot teams

New reactive behaviors that implement formations in multirobot teams are presented and evaluated. The formation behaviors are integrated with other navigational behaviors to enable a robotic team to reach navigational goals, avoid hazards and simultaneously remain in formation. The behaviors are implemented in simulation, on robots in the laboratory and aboard DARPAs HMMWV-based unmanned ground vehicles. The technique has been integrated with the autonomous robot architecture (AuRA) and the UGV Demo II architecture. The results demonstrate the value of various types of formations in autonomous, human-led and communications-restricted applications, and their appropriateness in different types of task environments.

Motor Schema — Based Mobile Robot Navigation:

Motor schemas serve as the basic unit of behavior specifica tion for the navigation of a mobile robot. They are multiple concurrent processes that operate in conjunction with asso ciated perceptual schemas and contribute independently to the overall concerted action of the vehicle. The motivation be hind the use of schemas for this domain is drawn from neuro- scientific, psychological, and robotic sources. A variant of the potential field method is used to produce the appropriate velocity and steering commands for the robot. Simulation re sults and actual mobile robot experiments demonstrate the feasibility of this approach.

Communication in reactive multiagent robotic systems

Multiple cooperating robots are able to complete many tasks more quickly and reliably than one robot alone. Communication between the robots can multiply their capabilities and effectiveness, but to what extent? In this research, the importance of communication in robotic societies is investigated through experiments on both simulated and real robots. Performance was measured for three different types of communication for three different tasks. The levels of communication are progressively more complex and potentially more expensive to implement. For some tasks, communication can significantly improve performance, but for others inter-agent communication is apparently unnecessary. In cases where communication helps, the lowest level of communication is almost as effective as the more complex type. The bulk of these results are derived from thousands of simulations run with randomly generated initial conditions. The simulation results help determine appropriate parameters for the reactive control system which was ported for tests on Denning mobile robots.

Integrating behavioral, perceptual, and world knowledge in reactive navigation

Reactive navigation based on task decomposition is an effective means for producing robust navigation in complex domains. By incorporating various forms of knowledge, this technique can be made considerably more flexible. Behavioral and perceptual strategies which are represented in a modular form and configured to meet the robots mission and environment add considerable versatility. A priori world knowledge, when available, can be used to configure these strategies in an efficient form. Dynamically acquired world models can be used to circumvent certain pitfalls that representationless methods are subject to. The Autonomous Robot Architecture (AuRA) is the framework within which experiments in the application of knowledge to reactive control are conducted. Actual robot experiments and simulation studies demonstrate the flexibility and feasibility of this approach over a wide range of navigational domains.

Motor schema based navigation for a mobile robot: An approach to programming by behavior

Motor schemas are proposed as a basic unit of behavior specification for the navigation of a mobile robot. These are multiple concurrent processes which operate in conjunction with associated perceptual schemas and contribute independently to the overall concerted action of the vehicle. The motivation behind the use of schemas for this domain is drawn from neuroscientific, psychological and robotic sources. A variant of the potential field method is used to produce the appropriate velocity and steering commands for the robot. An implementation strategy based on available tools at UMASS is described. Simulation results show the feasibility of this approach.

AuRA: principles and practice in review

This paper reviews key concepts of the Autonomous Robot Architecture (AuRA). Its structure, strengths, and roots in biology are presented. AuRA is a hybrid deliberative/ reactive robotic architecture that has been developed and refined over the past decade. In this article, particular focus is placed on the reactive behavioural component of this hybrid architecture. Various real world robots that have been implemented using this architectural paradigm are discussed, including a case study of a multiagent robotic team that competed and won the 1994 AAAI Mobile Robot Competition.

Multiagent Mission Specification and Execution

Specifying a reactive behavioral configuration for use by a multiagent team requires both a careful choice of the behavior set and the creation of a temporal chain of behaviors which executes the mission. This difficult task is simplified by applying an object-oriented approach to the design of the mission using a construction called an assemblage and a methodology called temporal sequencing. The assemblage construct allows building high level primitives which provide abstractions for the designer. Assemblages consist of groups of basic behaviors and coordination mechanisms that allow the group to be treated as a new coherent behavior. Upon instantiation, the assemblage is parameterized based on the specific mission requirements. Assemblages can be re-parameterized and used in other states within a mission or archived as high level primitives for use in subsequent projects. Temporal sequencing partitions the mission into discrete operating states with perceptual triggers causing transitions between those states. Several smaller independent configurations (assemblages) can then be created which each implement one state. The Societal Agent theory is presented as a basis for constructions of this form. The Configuration Description Language (CDL) is developed to capture the recursive composition of configurations in an architecture- and robot-independent fashion. The MissionLab system, an implementation based on CDL, supports the graphical construction of configurations using a visual editor. Various multiagent missions are demonstrated in simulation and on our Denning robots using these tools.

Cooperation without communication: Multiagent schema‐based robot navigation

Multiagent robotics affords the opportunity to solve problems more efficiently and effectively than any single agent could achieve. Nonetheless, communication bottlenecks between agents pose potentially serious drawbacks in coordinated behavior. In this research, we demonstrate the efficiency of multiagent schema-based navigation for object retrieval. Primitive motor behaviors are specified for each of the individual robotic agents, which produce safe task-achieving action in an unstructured environment. When implemented over several identical units, retrieval is facilitated in the absence of interagent communication as evidenced by spontaneous recruitment of several agents to accomplish a task. Simulation results are provided to demonstrate these effects. Extensions to other task-achieving behaviors are also feasible.

An Ethological and Emotional Basis for Human-Robot Interaction

Abstract This paper presents the role of ethological and emotional models as the basis for an architecture in support of entertainment robotic systems. Specific examples for Sony’s AIBO are presented as well as extensions related to a new humanoid robot, SDR.

Autonomous navigation in a manufacturing environment

Current approaches towards achieving mobility in the workplace are reviewed. The role of automatic guided vehicles (AGVs) and some of the preliminary work of other groups in autonomous vehicles are described. An overview is presented of the autonomous robot architecture (AuRA), a general-purpose system designed for experimentation in the domain of intelligent mobility. The means by which navigation is accomplished within this framework is specifically addressed. A description is given of the changes made to AuRA to adapt it to a flexible manufacturing environment, the types of knowledge that need to be incorporated, and the new motor behaviors required for this domain. Simulations of both navigational planning and reactive/reflexive motor schema-based navigation in a flexible manufacturing systems environment, followed by actual navigational experiments using the mobile vehicle, are presented. >