Polymorphic Robots Logan Hauenstein

Reading From Robot Teams, chapter 5: A Polymorphic Robot Team By Andres Castano and Peter Will

Homogeneous and Heterogeneous Teams Homogeneous Not as flexible – potential for weakness. Not as flexible – potential for weakness. Easier to maintain Easier to maintain Heterogeneous Takes advantage of different members Maintaining different robots is expensive Can we have the best of both worlds?

Polymorphic Robot Team Build a modular robot out of many homogeneous “building block” robots Build a modular robot out of many homogeneous “building block” robots Flexible like heterogeneous teams Flexible like heterogeneous teams Maintainable like homogeneous teams Maintainable like homogeneous teams Ultimate goal: reconfigurable robots, inter-robot reconfiguration Ultimate goal: reconfigurable robots, inter-robot reconfiguration

Homogeneous and Heterogeneous Reconfigurable Robots Homogeneous All modules are all the same All modules are all the same Module position determines role Module position determines role Less-costly hardware/software design process Less-costly hardware/software design process Simple to reconfigure Simple to reconfigureHeterogeneous Can have different modules Can have different modules Function of module determines role Function of module determines role Many different hardware/designs – costly Many different hardware/designs – costly Complex reconfiguration Complex reconfiguration

Level of Homogeneity Module Hardware Module Hardware Different modules mean higher development cost Different modules mean higher development cost Module Software Module Software Large, all-encompassing program? Or smaller, separate (overlapping) programs? Large, all-encompassing program? Or smaller, separate (overlapping) programs? Robot Hardware Robot Hardware Homogenous modules could get heavy Homogenous modules could get heavy Robot Software Robot Software Heterogeneous modules make reconfiguration hard Heterogeneous modules make reconfiguration hard

Latticed and Non-Latticed Reconfigurable Robots Latticed robots reconfigure in order to move Non-latticed robots usually have separate reconfiguration and locomotion stages.

Consequences Communication now required at both micro and macro level Communication now required at both micro and macro level Acts like a distributed system Acts like a distributed system How do you design a good reconfigurable robot unit? How do you design a good reconfigurable robot unit? Primary goals: Primary goals: Fixed-position functionality Fixed-position functionality Intra-robot reconfiguration Intra-robot reconfiguration Inter-robot reconfiguration Inter-robot reconfiguration

Challenges Need to find the right balance between weight, power, and capabilities Need to find the right balance between weight, power, and capabilities Communication: between modules and other robots Communication: between modules and other robots Remote Sensing to support reconfiguration Remote Sensing to support reconfiguration Self-reconfiguration presents a peg-in-a-hole problem Self-reconfiguration presents a peg-in-a-hole problem Autonomy: no human intervention Autonomy: no human intervention Self-Sufficiency: each has own CPU, power, etc. Self-Sufficiency: each has own CPU, power, etc.

The CONRO Module Two axes of rotation (yaw and pitch) Connection ports on each end: Other CONRO modules Special attachments like sensors, solar power units, etc. Self-sufficient Autonomous Images/movies courtesy of USC Information Sciences Institute

CONRO Implementation CONRO configured as a hexapod, loop, and snake. All are capable of locomotion.

CONRO Implementation Reconfiguration requires human help Software seems to handle reconfiguration well, though

Crystalline Modules: A Lattice Configuration The Crystalline Atom robots expand and contract to move the center of mass of the robot around.

More Examples: Above: The Polypod robot from PARC Modular Robotics is made up of compressible units. Left: IRobot’s 2PLHM – a polymorphic robot made up of many spherical “holons.”

More Examples: ( “Foglet” nanobots: extremely small polymorphic robots. On Certain Aspects of Utility Fog © 1996 J. Storrs Hall

Conclusions Neat idea, potentially terrifying Neat idea, potentially terrifying Still need to consider all various reconfiguration possibilities Still need to consider all various reconfiguration possibilities Real strength is in reconfiguration Real strength is in reconfiguration Maintaining all of those modules might be hard Maintaining all of those modules might be hard