1. How does a box work?

2. Starting state:
Objects OO and box B are at L.
Goal: Objects OO are at M.
Plan: for (O in OO) putin(O,B);
move(B,L,M);
repeat{choose(OX|removable(OX,B)),
takeout(OX,B)}
until(empty(B)).

3. STRIPS representation
Action: putin(O,B,L)
Preconditions: at(O,L), at(B,L), box(B)
Effects: in(O,B), ~at(O,L)
Action: move(B,L,M)
Preconditions: at(B,L)
Effects: at(B,M), ~at(B,L)
Action: takeout(O,B,L)
Preconditions: in(O,B), at(B,L)
Effects: at(O,L), ~in(O,B)

4. Limitations of STRIPS representation
No geometry.
Discrete atomic actions.
Does not generalize or share knowledge with similar situations.

5. Scientific Computing Equations: Newton’s laws, impact model.
Boundary conditions:
Shapes of objects
External forces on manipulators.
Solve (numerically) for trajectories.

6. Scientific Computing: Limitations
Requires exact specifications for shape and action. Cannot handle incomplete knowledge or generalization.
Unstable. Answer is not reliable.
Generates lots of useless intermediate states
Only supports prediction, not other types of reasoning: postdiction, diagnosis, design.

7. Knowledge-based qualitative physical reasoning
Representation for partial specifications of shape and action: 3D shape, continuous time
Rules to characterize dynamics of domain sufficient to support commonsense inferences
Effective reasoning strategies for different tasks.

8. Variants Objects can be carried on a tray but greater care is needed.
Large objects can be carried in a milkcrate, but small objects will fall through.
A box with a lid is safe against objects fallling out in transit.
etc.
Share knowledge.

9. Sample rule [holds(S,openBox(B,INTERIOR,TOP)) ^
forall(O in OO) [holds(S,in(place(O),INTERIOR)) ^
value(S,zeroVelocity(O))] ^
long([S,S1]) ^
throughout([S,S1], isolated(OO,B)) ^
throughout([S,S1], motionless(B))] =>
holds(S1,stable(OO U {B})) ^
forall(O in OO) holds(S1,in(place(O),INTERIOR))

10. And when we’ve finished boxes
How do pails and dippers work?