1. Temporal Planning: Part 2
Brian C. Williams
16.412J/6.834J
Oct 3rdst, 2001 1

2. Flexible Sequence (Plans)
Histories(?)
Goals
Projective
Task Expansion
Temporal
Planner
Scheduler
Flexible Sequence (Plans)
Task
Dispatch
Plan Runner
Goals
Modes
Model-based
Execution
(w planner)
Task-Decomposition
Execution
Reactive
Task Expansion
Observations
Commands

3. Outline Representing Plans Representing Time
Plan Consistency and Scheduling

4. Cassini Saturn Orbital Insertion
courtesy JPL

5. Planning in a continuous world
Attitude Control System

6. Planning in a continuous world Attitude Control System
Turn (a, b)
Attitude Control System

7. Planning in a continuous world Attitude Control System
Turn (a, b)
Attitude Control System

8. Planning in a continuous world Attitude Control System
Turn (a, b)
Attitude Control System

9. Planning in a continuous world Attitude Control System
Turn (a, b)
Attitude Control System

10. Planning in a continuous world Attitude Control System
Turn (a, b)
Attitude Control System

11. Planning in a continuous world Attitude Control System
Turn (a, b)
Attitude Control System

12. Planning in a continuous world: Attitude Control System
Point (b)
Attitude Control System

13. Planning in a continuous world: Attitude Control System
Point (b)
Attitude Control System

14. Action/State dichotomy in a continuous world Attitude Control System
Turn is an action, Point is a state
Both Turn and Point are actions
Both Turn and Point are state
Point (b)
Turn (a, b)
Attitude Control System

15. Both Actions and States are Tokens
Tokens represent procedure invocations
Thrust Goals
Delta_V(direction=b, magnitude=200)
Power
Attitude
Point(a)
Turn(a,b)
Point(b)
Turn(b,a)
Engine
Off
Warm Up
Thrust (b, 200)
Off

16. Planning Constraints are Specified by Compatibilities
Thrust Goals
Delta_V(?x, ?y)
Power
contained_by
equals
Attitude
Point(?x)
contained_by
meets
met_by
Engine
Warm Up
Thrust (?x, ?y)
Off f

17. Example of Compatibility Instantiation
Thrust Goals
Delta_V(direction=b, magnitude=200)
Power
contains
Attitude
Engine
Thrust (b, 200)

18. Example of Compatibility Instantiation
Thrust Goals
Delta_V(direction=b, magnitude=200)
Power
contained_by
equals
Attitude
Point(b)
contained_by
meets
met_by
Engine
Warm Up
Thrust (b, 200)
Off

19. Planner/Scheduler Architecture
Engine
Domain Knowledge
Search Control
Planning Experts
Search engine
Model
(DDL)
Goals
Plan
Plan Database
Initial state
to EXEC
from EXEC

20. Planner Resolves Flaws
Plan has flaws NO
Uninstantiated compatibility .
Instantiate compatibility .
Backtrack
Schedule token
Plan is consistent NO
YES

21. Types of Flaws No Disjunct of Compatibility Selected.
Unsatisfied Subgoal
There is a hole in the timeline immediately before Thrust (b, 200)
Floating Token, Needs to be Placed on Timeline.
Uninstantiated Variable in a Token
Thrust (?x = {a, b, c}, ?y = [190, 300]
The Plan Database can be modified only by primitives that resolve each of these flaws.

22. Planner/Scheduler Architecture
Engine
Domain Knowledge
Search Control
Planning Experts
Search engine
Model
(DDL)
Goals
Plan
Plan Database
Initial state
to EXEC
from EXEC

23. Search Control Determines Order and Type of Flaw Resolution
PLAN
f2I(P):
Plan has no subgoal
flaws T
Unsatisfied subgoal .
Search
Control
Instantiate subgoal . .
Backtrack
Schedule token
f1I(P):
Plan is consistent F
{T, ?}

24. Search Control Language
met_by
Turning_on( )
Ready( )
Camera:
(:subgoal
(:master-match (Camera = Ready))
(:slave-match (Camera = Turning_on)) 
(:priority 50)
(:method-priority ((:method :add) (:sort :asap))
((:method :connect))
((:method :defer))))

25. DS1 Planner/Scheduler
DS1 PS is a constraint-based, backtrack search, generative planner operating on a fully temporal domain model
Model size (Remote Agent Experiment)
state variables 18
procedure types 42
Plan size
tokens 154
variables (81 time points)
constraints (114 distance bounds)
Performance
search nodes 649
search efficiency %

26. Flexible Sequence (Plans)
Histories(?)
Goals
Projective
Task Expansion
Temporal
Planner
Scheduler
Flexible Sequence (Plans)
Task
Dispatch
Plan
Runner
Goals
Modes
Model-based
Execution
(w planner)
Task-Decomposition
Execution
Reactive
Task Expansion
Observations
Commands