Ernesto Nunes

AAMAS Conference 2016 Conference Paper

Iterated Multi-Robot Auctions for Precedence-Constrained Task Scheduling

• Mitchell McIntire
• Ernesto Nunes
• Maria Gini

AAAI Conference 2016 Conference Paper

Monte Carlo Tree Search for Multi-Robot Task Allocation

• Bilal Kartal
• Ernesto Nunes
• Julio Godoy
• Maria Gini

Multi-robot teams are useful in a variety of task allocation domains such as warehouse automation and surveillance. Robots in such domains perform tasks at given locations and specific times, and are allocated tasks to optimize given team objectives. We propose an efficient, satisficing and centralized Monte Carlo Tree Search based algorithm exploiting branch and bound paradigm to solve the multi-robot task allocation problem with spatial, temporal and other side constraints. Unlike previous heuristics proposed for this problem, our approach offers theoretical guarantees and finds optimal solutions for some non-trivial data sets.

AAAI Conference 2015 Conference Paper

Multi-Robot Auctions for Allocation of Tasks with Temporal Constraints

• Ernesto Nunes
• Maria Gini

We propose an auction algorithm to allocate tasks that have temporal constraints to cooperative robots. Temporal constraints are expressed as time windows, within which a task must be executed. There are no restrictions on the time windows, which are allowed to overlap. Robots model their temporal constraints using a simple temporal network, enabling them to maintain consistent schedules. When bidding on a task, a robot takes into account its own current commitments and an optimization objective, which is to minimize the time of completion of the last task alone or in combination with minimizing the distance traveled. The algorithm works both when all the tasks are known upfront and when tasks arrive dynamically. We show the performance of the algorithm in simulation with different numbers of tasks and robots, and compare it with a baseline greedy algorithm and a state-ofthe-art auction algorithm. Our algorithm is computationally frugal and consistently allocates more tasks than the competing algorithms.

AAMAS Conference 2012 Conference Paper

Auctioning Robotic Tasks with Overlapping Time Windows

• Ernesto Nunes
• Maitreyi Nanjanath
• Maria Gini

This work investigates allocation of tasks to multi-robots when tasks are spatially distributed and constrained to be executed within assigned time windows. Our work explores the interaction between scheduling and optimal routing. We propose the Time-Sensitive Sequential Single-Item Auction algorithm as a method to allocate tasks with time windows in multi-robot systems. We show, experimentally, that the proposed algorithm outperforms other auction algorithms that we modified to handle time windows.