l13a_reacti_plan

l13a_reacti_plan - RMPL Model-based Program Reactive...

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Reactive Planning of Hidden States in Large State Spaces Through Decomposition and Serialization Brian C. Williams Joint with Seung H. Chung 16.412J/6.834J March 16 th , 2005 Environment Model Commands Observations Control Program Kirk Model-based Executive RMPL Model-based Program location goals location estimates Selects consistent threads of activity from redundant methods Tracks location Finds least cost paths Executes concurrently Preempts non -deterministic choice A[l,u ] timing A at l location HOME T W O Enroute COL ECTION POINT RENDEZVOUS Diverge SCIENCE AREA 1’ SCIENCE AREA 3 Landing Site: ABC Landing Site: XYZ O N E SCIENCE AREA 1 Executive pre-plans activities pre-plans paths dynamically schedules [Tsmardinos et al.] Plant Schedules and Dispatches Activities Dynamically CSAIL Massachusetts Institute of Technology Outline • The need for model-based reactive planning • The Burton model-based reactive planner CSAIL Massachusetts Institute of Technology DS 1 Attitude Control System z facing thrusters x facing thrusters 1553 bus Commands Data N 2 H 4 He SRU PDU GDE PASM DSEU PEPE Flight Computer BC PDE Livingstone reconfigured modes using one step commands. But how does the flight computer really open a valve? • Requires turning on device drivers • Requires repairing bus controllers • Sending commands • Powering down devices . . . CSAIL Massachusetts Institute of Technology Remote Terminal Remote Terminal Driver Bus Control Computer Valve Driver Valve • Device modes are changed through indirect commanding . • Communication paths are established by reconfiguring other devices. • The task of reconfiguring devices in the proper order generalizes state- space planning to handle indirect effects. • To achieve reactivity all possible plans for all possible goal states should be pre -compiled (a generalization of universal plans). ± To achieve compactness we decompose these universal plans according to a goal/sub-goal hierarchy. How do we reconfigure a valve? Massachuset s Institute of Technology MERS Model- based Embed ed & Robotic Systems Group Mode Reconfiguration Model -based Programming of Intelligent Embedded Systems and Robotic Explorers [Williams et al., IEEE’03] Reactive Planner for a Model -based Executive [Wil iams & Nayak, IJCAI 97] Goal Interpreter Configuration Goal Command Goal State State Estimate (Current) Reactive Planner Command Goal State State Estimate (Current) 1
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CSAIL Massachusetts Institute of Technology Example: Driver Valve Command Sequence Valve Driver dr Valve vlv vcmdin dcmdin Commands Driver State Valve State ME: dr = off, vlv = open GI: dr = off, vlv = closed MRP dcmdin = on ME: dr = on, vlv = open MRP dcmdin = close ME: dr = reset failure, vlv = open MRP dcmdin = reset ME: dr = on, vlv = open MRP dcmdin = off ME: dr = off, vlv = open Goal: No thrust CSAIL Massachusetts Institute of Technology To achieve reactivity we eliminate all forms of search.
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This note was uploaded on 11/07/2011 for the course AERO 16.410 taught by Professor Brianwilliams during the Fall '05 term at MIT.

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l13a_reacti_plan - RMPL Model-based Program Reactive...

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