RMPL Model-based program Titan Model-based Executive Control Program Control Sequencer Executes concurrently Generates goal states ts conditioned on state estimates Asserts and queries states Chooses based on reward State estimates System Model State goals -ExO Mode Estimation: Reconfiguration Tracks likely Tracks least-cost States state goals Commands ons Valve fails Plan stuck closed Fire backup engine Q least cost reachable Current Belief State First Action goal state
Control Sequencer Deductive Controller System Model Commands Observations Control Program Plant RMPL Model-based Program Titan Model-based Executive State estimates State goals Control Sequencer: Generates goal states conditioned on state estimates Mode Estimation: Tracks likely States Mode Reconfiguration: Tracks least-cost state goals z Executes concurrently z Preempts z Asserts and queries states z Chooses based on reward Closed Valve Open Stuck open Stuck closed Open Close 0. 01 0. 01 0.01 0.01 inflow = outflow = 0 Fire backup engine Valve fails stuck closed S T X0 X1 XN-1 XN S T X0 X1 XN-1 XN least cost reachable Current Belief State First Action goal state
arg max Pt(m arg min rT*(m S t. M(m)o(m)is satisfiable S.t. M(m)entails g(m) S.t. M(m)is satisfiable State estimates State goals Optimal cSP arg min f(x) Mode Mode Estimation: Reconfiguration S.t. C(x)is satisfiable Tracks likely Tracks least-cost D(x)is unsatisfiable States state goals Commands ons Valve fails stuck closed Fire backup engine Q least cost reachable Current Belief State First Action goal state
Deductive Controller Commands Observations Plant State estimates State goals Mode Estimation: Tracks likely States Mode Reconfiguration: Tracks least-cost state goals Fire backup engine Valve fails stuck closed S T X0 X1 XN-1 XN S T X0 X1 XN-1 XN least cost reachable Current Belief State First Action goal state Optimal CSP: arg min f(x) s.t. C(x) is satisfiable D(x) is unsatisfiable arg max P T(m’) s.t. M(m’) ^ O(m’) is satisfiable arg min RT*(m’) s.t. M(m’) entails G(m’) s.t. M(m’) is satisfiable
A simple model-based executive(Livingstone) commanded NASA's Deep Space One probe Deep Space One Started: January 1996 taunch: October 15th. 1998 Remote Agent Experiment: May, 1999 courtesy NASA JPL Massachusetts Institute of Technology
Artificial Intelligence & Space Systems Laboratories Massachusetts Institute of Technology A simple model-based executive (Livingstone) commanded NASA’s Deep Space One probe courtesy NASA JPL Started: January 1996 Launch: October 15th, 1998 Remote Agent Experiment: May, 1999
Remote Agent Experiment See rax arc. nasa. gov May 17-18th experiment Generate plan for course correction and thrust Diagnose camera as stuck on Power constraints violated, abort current plan and replan Perform optical navigation Perform ion propulsion thrust May 21th experiment Diagnose faulty device and Repair by issuing reset Diagnose switch sensor failure Determine harmless, and continue plan Diagnose thruster stuck closed and Repair by switching to alternate method of thrusting Back to back planning Massachusetts Institute of Technology
Artificial Intelligence & Space Systems Laboratories Massachusetts Institute of Technology Remote Agent Experiment May 17-18th experiment • Generate plan for course correction and thrust • Diagnose camera as stuck on – Power constraints violated, abort current plan and replan • Perform optical navigation • Perform ion propulsion thrust May 21th experiment. • Diagnose faulty device and – Repair by issuing reset. • Diagnose switch sensor failure. – Determine harmless, and continue plan. • Diagnose thruster stuck closed and – Repair by switching to alternate method of thrusting. • Back to back planning See rax.arc.nasa.gov
Outline Model-based programming The need for model-based reactive planning The burton model-based reactive planner Massachusetts Institute of Technology
Artificial Intelligence & Space Systems Laboratories Massachusetts Institute of Technology Outline • Model-based programming • The need for model-based reactive planning • The Burton model-based reactive planner