Metamorphic Robots
Related: Multi-Robot  

Project Alumni: Jennifer Walter, Mary Brooks, David Little

Supported By: NSF, Texas Higher Education Coordinating Board

A metamorphic robotic system is a collection of identical, independently controlled modules. The modules can connect, disconnect, and move around adjacent modules. Metamorphic robots attract interest because they are robust, cost-efficient, and useful in dangerous environments. Because the modules are all identical, if one breaks down, any other module can take its place. Metamorphic robots are cost-efficient because they can be mass-produced. The modules are independently controlled, so they can be used in environments where humans cannot directly observe or control them, such as interplanetary space.


Currently, we are researching decentralized algorithms to control the movement of the modules when irregular obstacles are in the way. We study two-dimensional, hexagonal metamorphic robots.







Related Publications

Enveloping multi-pocket obstacles with hexagonal metamorphic robots, Jennifer E. Walter, Mary E. Brooks, David F. Little, Nancy M. Amato, In Proc. IEEE Int. Conf. Robot. Autom. (ICRA), Vol: 3, pp. 2204-2209, New Orleans, Louisiana, USA, Apr 2004. DOI: 10.1109/ROBOT.2004.1307389
Keywords: Mobile Robots, Motion Planning, Multi-Agent
Links : [Published]

BibTex

@INPROCEEDINGS{1307389,
author={J. E. {Walter} and M. E. {Brooks} and D. F. {Little} and N. M. {Amato}},
booktitle={IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004}, title={Enveloping multi-pocket obstacles with hexagonal metamorphic robots},
year={2004},
volume={3},
number={},
pages={2204-2209 Vol.3},
doi={10.1109/ROBOT.2004.1307389}}


Abstract

The problem addressed is reconfiguration planning for a metamorphic robotic system composed of any number of hexagonal robots when a single obstacle with multiple indentations or "pockets" is embedded in the goal environment. We extend our earlier work on filling a single pocket in an obstacle to the case where the obstacle surface may contain multiple pockets. The planning phase of our algorithm first determines whether the obstacle pockets provide sufficient clearance for module movement, i.e., whether the obstacle is "admissible". In this paper, we present algorithms that sequentially order individual pockets and order module placement inside each pocket. These algorithms ensure that every cell in each pocket is filled and that module deadlock and collision do not occur during reconfiguration. This paper also provides a complete overview of the planning stage that is executed prior to reconfiguration and presents a distributed reconfiguration schema for filling more than one obstacle pocket concurrently, followed by the envelopment of the entire obstacle. Lastly, we present examples of obstacles with multiple pockets that were successfully filled using our distributed reconfiguration simulator.


Enveloping Obstacles with Hexagonal Metamorphic Robots, Jennifer E. Walter, Mary E. Brooks, David F. Little, Nancy M. Amato, Proc. IEEE Int. Conf. Robot. Autom. (ICRA), Vol: 1, pp. 741-748, Taipei, Taiwan, Jan 2003. DOI: 10.1109/ROBOT.2003.1241682
Keywords: Mobile Robots, Motion Planning, Multi-Agent
Links : [Published]

BibTex

@INPROCEEDINGS{1241682,
author={J. E. {Walter} and E. M. {Tsai} and N. M. {Amato}},
booktitle={2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422)}, title={Enveloping obstacles with hexagonal metamorphic robots},
year={2003},
volume={1},
number={},
pages={741-748 vol.1},
doi={10.1109/ROBOT.2003.1241682}}


Abstract

The problem addressed is the distributed reconfiguration of the metamorphic robot system composed of any number of two dimensional robots (modules). The initial configuration we consider is a straight chain of modules, while the goal configuration satisfies a simple admissibility condition. Our reconfiguration strategy depends on finding a contiguous path of cells, called a substrate path that spans the goal configuration. Modules fill in this substrate path and then move along the path to fill in the remainder of the goal without collision or deadlock. In this paper, we address the problem of reconfiguration when a single obstacle is embedded in the goal environment. We introduce a classification for traversable surfaces, which allows for coherence in defining admissibility characteristics for various objects in the hexagonal grid. We present algorithms to 1) determine if an obstacle embedded in the goal fulfills a simple admissibility requirement, 2) include an admissible obstacle in a substrate path, and 3) accomplish distributed reconfiguration.