Formulation and Implementation of Relational Behaviours for MultiRobot

Formulation and Implementation of Relational Behaviours for Multi-Robot Cooperative Systems INSTITUTO DE SISTEMAS E ROBÓTICA Bob van der Vecht Institute for Systems and Robotics Instituto Superior Técnico Lisbon, PORTUGAL

Overview Framework for Relational Behaviours – Decision Making – Synchronization The Pass Behaviour INSTITUTO DE SISTEMAS E ROBÓTICA – Logical Conditions – Individual Behaviours Results

Example INSTITUTO DE SISTEMAS E ROBÓTICA

Framework for Relational Behaviours Decision Making – Architecture: Logic Machine – 3 Behaviour Levels: 1. INSTITUTO DE SISTEMAS E ROBÓTICA 2. 3. Organizational, (defender, attacker) Relational, (pass commitment) Individual, (go. To, intercept) Synchronization – Explicit communication

Relational Behaviour Selection Joint Commitment Theory INSTITUTO DE SISTEMAS E ROBÓTICA – Logical conditions can establish a commitment between agents – Commitment holds until conditions are FALSE, or goal is achieved Commitment Phases – Setup, Loop, End – Logic Machine Relational Behaviours selection: Setup Loop End none commitment none

Primitive Behaviour Selection Synchronization – Commitment states: Setup INSTITUTO DE SISTEMAS E ROBÓTICA request accept Loop End state 1. . . state n done Default failed none

Primitive Behaviour Selection Synchronization – Commitment states – Logic Machine Primitive Behaviour selection: Setup INSTITUTO DE SISTEMAS E ROBÓTICA Loop End Default state 1. . . state n done failed none request accept Agent 1 ---- A C ---- Agent 2 ---- B D ---- – – A, B, C and D : Primitive behaviours. Every state in the Loop is linked to a set of primitive behaviours

Synchronization Variables: INSTITUTO DE SISTEMAS E ROBÓTICA - commitment. agent 1. state - commitment. agent 2. state l Agents can only change commitment. <own>. state l Changed variable is sent to the partner Setup: - agent 1 sets request - agent 2 accepts Loop: - Update own state variable - Switch to new state - Select behaviour End: Clear all variables

The Pass Behaviour INSTITUTO DE SISTEMAS E ROBÓTICA

The Pass Behaviour Logic Machine – Relational Behaviours selection: Setup Loop End none pass none INSTITUTO DE SISTEMAS E ROBÓTICA – Primitive Behaviour selection: Setup Loop End request accept preparing intercept done Kicker ---- aim. Andpass stand. By Receiver ---- stand. By intercept Default failed none ---- ----

The Pass Behaviour Logical Conditions Switch to state Conditions INSTITUTO DE SISTEMAS E ROBÓTICA request Player Role Player has ball Player on own half of field = defender = TRUE Accept Pass. kicker. state = request Player Role Player on other half of field = attacker = TRUE Pass. receiver. state = accept Commitment Role = kicker Intercept Commitment Role Ball shot = kicker = TRUE Done Commitment Role Intereption Result = receiver = success Failed Any behaviour failure Preparing

The Pass Behaviour Individual Behaviours: – aim. And. Pass: turn with ball in desired direction and shoot. uses: Dribble Controller INSTITUTO DE SISTEMAS E ROBÓTICA – Intercept: intercept moving ball Calculate interception point, using: – estimated ball path – estimated robot path – assumption: Ball and Robot move in straight line, with constant velocity to intercaption point.

Results Pass Behaviour – Runs in general as expected – Synchronization works well – Result depends on Individual Behaviours INSTITUTO DE SISTEMAS E ROBÓTICA

Results Aim. And. Pass INSTITUTO DE SISTEMAS E ROBÓTICA Angle (deg) Dist (m) Time (s) Error (cm) 1 132 4. 5 3. 26 -17 2 138 4. 5 2. 59 Failure 3 133 4. 5 3. 30 +22 4 133 4. 5 3. 30 -20 5 135 4. 5 3. 28 -9 6 137 4. 5 1. 98 Failure 7 134 4. 5 3. 48 +3 8 134 4. 5 3. 20 -23 9 134 4. 5 3. 16 -9 10 133 4. 5 3. 23 +4 134. 3 4. 5 3. 28 -6. 1

Results: Intercept INSTITUTO DE SISTEMAS E ROBÓTICA

Results: Intercept INSTITUTO DE SISTEMAS E ROBÓTICA 5 succes 2 bumps 7 failed 3 bumps 5 12 1 missed 2 perfect 4 missed 5 2

Results: Intercept Ball not moving INSTITUTO DE SISTEMAS E ROBÓTICA

Future Research Develop new relational behaviours – Setup Conditions – Other Switch conditions (more reactive) – Other individual behaviours INSTITUTO DE SISTEMAS E ROBÓTICA Improve Primitive Behaviours