Asynchronous Consensus Protocols: Preliminary Results, Simulations and Open Questions

Consensus is well accepted as being a fundamental paradigm for coordination of groups of autonomous agents. Recently, we casted previous work on multi-agent consensus protocols into an asynchronous framework, where each agent updates on its own pace, and uses the most recently received information from other agents. Asynchronous consensus protocols encompass those synchronous ones with various communication patterns. In this paper, we study via simulation a number of open new problems introduced by the asynchronous operation of multi-agent systems. More interestingly, the existing consensus results are classified by their communication assumptions and future research directions are proposed. To facilitate our study, we develop a multi-vehicle simulator in Java, built on top of JProwler; JProwler is a discrete event simulator for prototyping, verifying and analyzing communication protocols of ad-hoc wireless networks. Implementation issues with their implications are also discussed.

[1]  Randal W. Beard,et al.  Dynamic Consensus Seeking in Distributed Multi-agent Coordinated Control , 2004 .

[2]  J.N. Tsitsiklis,et al.  Convergence in Multiagent Coordination, Consensus, and Flocking , 2005, Proceedings of the 44th IEEE Conference on Decision and Control.

[3]  Andrey V. Savkin,et al.  Coordinated collective motion of Groups of autonomous mobile robots: analysis of Vicsek's model , 2004, IEEE Transactions on Automatic Control.

[4]  Richard M. Murray,et al.  Consensus problems in networks of agents with switching topology and time-delays , 2004, IEEE Transactions on Automatic Control.

[5]  Ping Liang,et al.  Pattern reconfiguration in swarms-convergence of a distributed asynchronous and bounded iterative algorithm , 1996, IEEE Trans. Robotics Autom..

[6]  Victor S. Kozyakin.  Asynchronous systems: a short survey and problems∗ , 2003 .

[7]  R.M. Murray,et al.  Distributed Averaging on Asynchronous Communication Networks , 2005, Proceedings of the 44th IEEE Conference on Decision and Control.

[8]  Marios M. Polycarpou,et al.  Stability analysis of M-dimensional asynchronous swarms with a fixed communication topology , 2002, Proceedings of the 2002 American Control Conference (IEEE Cat. No.CH37301).

[9]  Huaiqing Wang,et al.  Multi-agent coordination using nearest neighbor rules: revisiting the Vicsek model , 2004, ArXiv.

[10]  Marios M. Polycarpou,et al.  Stability analysis of one-dimensional asynchronous swarms , 2003, Proceedings of the 2001 American Control Conference. (Cat. No.01CH37148).

[11]  Mireille E. Broucke,et al.  Local control strategies for groups of mobile autonomous agents , 2004, IEEE Transactions on Automatic Control.

[12]  Timothy W. McLain,et al.  Coordination Variables and Consensus Building in Multiple Vehicle Systems , 2004 .

[13]  Stephen P. Boyd,et al.  Fast linear iterations for distributed averaging , 2003, 42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475).

[14]  R. Beard,et al.  Consensus of information under dynamically changing interaction topologies , 2004, Proceedings of the 2004 American Control Conference.

[15]  Luc Moreau,et al.  Stability of multiagent systems with time-dependent communication links , 2005, IEEE Transactions on Automatic Control.

[16]  Felisa J. Vázquez-Abad,et al.  Centralized and decentralized asynchronous optimization of stochastic discrete-event systems , 1998 .

[17]  Gilbert Crombez,et al.  Finding common fixed points of a class of paracontractions , 2004 .

[18]  Jie Lin,et al.  Coordination of groups of mobile autonomous agents using nearest neighbor rules , 2003, IEEE Trans. Autom. Control..

[19]  Markku Verkama.  Random Relaxation of Fixed-Point Iteration , 1996, SIAM J. Sci. Comput..

[20]  R. Pesenti,et al.  Attitude alignment of a team of UAVs under decentralized information structure , 2003, Proceedings of 2003 IEEE Conference on Control Applications, 2003. CCA 2003..

[21]  Panos J. Antsaklis,et al.  On communication requirements for multi-agent consensus seeking , 2006 .

[22]  Luc Moreau,et al.  Leaderless coordination via bidirectional and unidirectional time-dependent communication , 2003, 42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475).

[23]  Jean-Jacques E. Slotine,et al.  A Study of Synchronization and Group Cooperation Using Partial Contraction Theory , 2004 .

[24]  Randy Beard,et al.  Information consensus in distributed multiple vehicle coordinated control , 2003, 42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475).

[25]  D. Szyld,et al.  On asynchronous iterations , 2000 .

[26]  Marios M. Polycarpou,et al.  Stability analysis of one-dimensional asynchronous mobile swarms , 2001, Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228).

[27]  E. Kaszkurewicz,et al.  FURTHER RESULTS ON CONVERGENCE OF ASYNCHRONOUS LINEAR ITERATIONS , 1998 .

[28]  F. Paganini,et al.  Convex synthesis of controllers for consensus , 2004, Proceedings of the 2004 American Control Conference.

[29]  E.M. Atkins,et al.  A survey of consensus problems in multi-agent coordination , 2005, Proceedings of the 2005, American Control Conference, 2005..

[30]  John N. Tsitsiklis,et al.  Parallel and distributed computation , 1989 .

[31]  P.J. Antsaklis,et al.  Information consensus of asynchronous discrete-time multi-agent systems , 2005, Proceedings of the 2005, American Control Conference, 2005..

[32]  B.D.O. Anderson,et al.  The multi-agent rendezvous problem - the asynchronous case , 2004, 2004 43rd IEEE Conference on Decision and Control (CDC) (IEEE Cat. No.04CH37601).

[33]  Mehran Mesbahi,et al.  Agreement over random networks , 2004, 2004 43rd IEEE Conference on Decision and Control (CDC) (IEEE Cat. No.04CH37601).

[34]  Ming Cao,et al.  COORDINATION OF AN ASYNCHRONOUS MULTI-AGENT SYSTEM VIA AVERAGING , 2005 .