Distributed evaluation functions for fault tolerant multi-rover systems

The ability to evolve fault tolerant control strategies for large collections of agents is critical to the successful application of evolutionary strategies to domains where failures are common. Furthermore, while evolutionary algorithms have been highly successful in discovering single-agent control strategies, extending such algorithms to multi-agent domains has proven to be difficult. In this paper we present a method for shaping evaluation functions for agents that provide control strategies that are both tolerant to different types of failures and lead to coordinated behavior in a multi-agent setting. This method neither relies on a centralized strategy (susceptible to single points of failures) nor a distributed strategy where each agent uses a system wide evaluation function (severe credit assignment problem). In a multi-rover problem, we show that agents using our agent-specific evaluation perform up to 500% better than agents using the system evaluation. In addition we show that agents are still able to maintain a high level of performance when up to 60% of the agents fail due to actuator, communication or controller faults.