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Decentralized Task Allocation for Heterogeneous Teams

with Cooperation Constraints

Presented by: Sin Ting, Angela, LuiARC Centre of Excellence for Autonomous Systems

Han-Lim Choi, Andrew K. Whitten, and Jonathan P. How

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Outline

• Problem• Paper Contribution• Consensus Based Bundle Algorithm• Task Decomposition / Scoring• Task Elimination• Results

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Problem

Allocation task of agents to tasks.Given a list of J tasks of K types, and I

agents of M types. Find the mapping of tasks to a required set of agents that maximize some global reward.

a) Solo Task (Tracking)b) Preferred Duo Task (Tracking)c) Required Duo Task (Tracking and

striking)

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ProblemOptimization:

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Contribution

• Extending Consensus Bundle Based Algorithm to number of agents on task.

• Constraints due to requirements & preferences of cooperation.

• Embedding cooperation constraints in the scorings structure.

• Decentralized methods to eliminate invalid assignment.

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Consensus Based Bundle Algorithm (CBBA)Consensus-Based Decentralized Auctions for Robust Task

Allocation (2009, H.Choi, L.Brunet and J.P.How)Based off winning agents and winning

scores. 1) Bundle 2) Consensus (Conflict Resolution)Each agent carries five vectors

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CBBA

1) Bundle- are tasks added based on time.- list based on location in the assignment

which incurs the largest score improvement.

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CBBA

2) Conflict Resolution- the winning bid list.- the winning agent list.- d time stamps of the last information

update.If is different between two agents, the

agent that receives the message will update, leave, or reset the task assignment.

If there are any changes, the bundle is released and the agent has to replan.

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CBBA

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CBBA - Example

Example & figures from MIT CBBA code

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CBBA

Example & figures from MIT CBBA code

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Consensus Based Bundle Algorithm (CBBA)

Advantages:• Polynomial time algorithm. • Scales well with network and numbers

of tasks. • Accounts for inconsistent information

among networked agents. Disadvantages:• Allocation only allows one agent per

task

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Task Decomposition & Scoring

Task Decomposition for Preferred Duo Task

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Task Decomposition & Scoring

Task Decomposition for Required Duo Task

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Task Decomposition & Scoring

Constraint to not allow a single agent to bid for the same task twice.

Constraint for required duo

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Task Decomposition & ScoringOptimization:

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Task Decomposition & Scoring

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Decentralized Task Elimination

After CBBA converges, the subtask allocations for required duo tasks will either be:

1) Both subtasks are assigned.2) Both subtasks are not assigned.3) Only one subtask is assigned.

Since is the same for all agents when CBBA converges, each agent can reconstruct the bundle of other agents and eliminate invalid tasks in their bundle.

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Decentralized Task Elimination

Final Proposed Algorithm:

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Results

Track & Eliminate Task. Task allocation improvement over baseline CBBA.

Figure 1 from Paper

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Results

Figure 2&3 from Paper

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Questions?

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