Central Place Foraging: Delivery Lanes, Recruitment and Site Fidelity

Abstract

Central Place Foraging is a behavior in which many agents search an unknown environment for resources and then collect the resources to return them to a central location. We seek to emulate this behavior using a multi-agent system of wheeled mobile robots. Many attributes of this system, such as inter-agent congestion, inter-agent communication, and the use of memory, can impact the efficiency of the system. This study seeks to evaluate the impact that each of these mechanisms play on the rate of resource collection in Central Place Foraging. Three mechanisms were evaluated including the use of delivery lanes around the central depot, site fidelity, and recruitment. Delivery lanes are claimable points around the central collection depot meant to alleviate inter-agent congestion. If an agent has claimed a delivery lane, then other agents avoid this area until the claiming agent has delivered the resource and left the area. Agents utilizing site fidelity use memory to return to the last known resource location before resuming its search after delivering a resource to the collection depot. Lastly, recruitment uses inter-agent communication to alert other agents to assist with resource collection when resources are found. The behaviors were implemented and evaluated using a high-fidelity simulation environment built with ROS and Gazebo. Each behavior included the same randomized search algorithm which is intended to provide uniform coverage of the environment. Simulations were conducted using three robots across twenty-six randomly generated environments while collecting data on the rate of resource collection. The results show that site fidelity has the largest effect on overall performance of the system. Recruitment has a positive but marginal effect while delivery lanes did not show an increase in overall performance.