Fundamental Paper on Formation Control For CS 7631: Multi Robot Systems Diogenes Molina

1. Fundamental Paper on Formation Control For CS 7631: Multi Robot Systems Diogenes Molina School of Interactive Computing Georgia Tech March 15, 2012

2. The Paper • Radhika, Nagpal, “Programmable Self-Assembly Using Biologically-Inspired Multiagent Control,” in Proceedings of the 1st International Joint Conference on Autonomous Agents and Multiagent Systems, pp. 418-425, New York, 2002.

3. Outline • Problem statement and motivation • Brief overview of previous work • Insights from developmental biology • Proposed multiagent control methodology for programmable self-assembly • Origami-inspired operations for global shape specification • Cell biology-inspired primitives • From global shapes to local primitives • Simulation results • Paper critique • Questions

4. Problem statement and motivation (1) • How to design/program self-assembling complex structures from locally interacting homogeneous agents? ?????

5. Problem statement and motivation (2) • Emerging technologies make approaches of this type attractive • But. mapping global objectives to decentralized local rules is hard • Limited agent resources • Reliability

6. Brief overview of previous work • Hierarchical and centralized approaches dominate • Can be unreliable and not fault-tolerant • Expensive and complex agents can be costly • Approaches based on cellular automata and artificial life are difficult to generalize • There is no framework for generating local rules automatically • Learning and evolutionary approaches

7. Insights from developmental biology • Biological systems are a clear proof that this can be done effectively! • The inner workings of these systems can provide inspiration • Morphogenesis and developmental biology as a source of mechanisms and general principles • Implement some of these mechanisms as a programming language • Epithelial cell behavior

8. Multiagent methodology for programmable self-assembly • Sheet and Agent Model

9. Multiagent programmable self-assembly (1) • OSL: origami-inspired language for global shape specification

10. Multiagent programmable self-assembly (2) • Biologically-inspired local primitives • Gradients • Neighborhood query • Polarity inversion • Cell-to-cell contact • Flexible folding

11. Multiagent programmable self-assembly (3) • Axiom implementation via local primitives

12. Multiagent programmable self-assembly (4) • From OSL to agent program

13. Simulation results

14. Criticism • Many shapes cannot be constructed using the axioms • The initialization of the sheet is providing a certain amount of “global” information • The simulation environment seems too artificial • Not clear about how the folding process is executed • Some global synchronization must be occurring, but not discussed • The symmetry of the sheet might not be satisfied in some cases, but could have a huge impact

16. A. Huzita’s Axioms

17. B. Epithelial cells reference http://en.wikipedia.org/wiki/Epithelium http://www.bio.davidson.edu/people/kabernd/BerndCV/Lab/EpithelialInfoWeb/index.html