Incremental Contingency Planning Richard Dearden, Nicolas Meuleau, Sailesh Ramakrishnan, David E' Sm

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Incremental Contingency Planning Richard
Dearden, Nicolas Meuleau, Sailesh Ramakrishnan,
David E. Smith, Rich Washington
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2
Why Contingency Planning ??
Limited onboard processing CPU, memory,
time Safety sequence checking Anticipation setup
steps
3
The Planning Problem
Given start time pose energy available actions
with uncertain durations resource usage Possible
science objectives images samples
Compress

Visual servo (.2, -.15)
Dig(5)
Drive(-1)
NIR
Drive(2)
Warmup NIR
Maximize (Expected) Scientific Return
4
Technical Challenges
Continuous time ( resources) Continuous
outcomes Time ( resource) constraints Concurren
cy Goal selection optimization g1, g2, g3, g4

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Just in Case (JIC) Scheduling
1. Seed schedule 2. Identify most likely
failure 3. Generate a contingency
branch 4. Integrate the branch
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Advantages Tractability Simple plans Anytime
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Just in Case (JIC) Planning
1. Seed plan 2. Identify most likely
failure 3. Generate a contingency
branch 4. Integrate the branch
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.2
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Limits of JIC Scheduling Heuristics
t ? 900, 1430 ? 5s ? 1s
? most probable failures most
interesting branch point
Most probable failure points may not be the best
branch-points It is often too late to attempt
other goals when the plan is about to fail.
V 10
HiRes
t ? 1000, 1400 ? 600s ? 60s
? 300s ? 5s
? 120s ? 60s
? 1000s ? 500s

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V 100
Dig(60)
Visual servo (.2, -.15)
Drive (-2)
NIR
t ? 900, 1600 ? 5s ? 1s
t ? 1000, 1350 ? 600s ? 60s
? 120s ? 20s
V 50
Lo res
Rock finder
LIB
V 5
Warmup LIB
True for all initial states in the grey box.
? 1200s ? 20s
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Just in Case (JIC) Planning
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1. Seed plan 2. Identify best branch
point 3. Generate a contingency branch 5.
Evaluate Integrate the branch
Construct plangraph Back-propagate value
tables Compute gain Select branch condition
goals
Vm
Vb
r
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Construct Plangraph
g1
g2
g3
g4
10
Value Tables
V1
g1
r
V2
g2
r
V3
g3
r
V4
g4
r
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Example
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
12
Simple Propagation
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Simple Propagation
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Simple Propagation
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
15
Conjunctions
q
g
A
B
(10, 15)
(10, 15)
p
t
1
C
r
2
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Propagation
q
g
A
B
(10, 15)
(10, 15)
p
t
1
C
r
2
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Propagation
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Combining Tables
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Discharging Assumptions
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Propagation
q
g
A
B
(10, 15)
(10, 15)
p
C
r
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Combining Tables
q
g
A
B
(10, 15)
(10, 15)
p
1
C
r
5
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Combining Tables
q
g
A
B
5
(10, 15)
(10, 15)
p
25
8
1
C
r
5
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Ordering
q
g
A
B
AB
5
(10, 15)
CDE
(10, 15)
p
25
8
1
C
r
5
(3, 3)
E
g
(2, 2)
D
s
t
DCE
(1, 5)
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Achieving Multiple Goals
gg
g

5
g
25
15
30
q
g
A
B
5
(10, 15)
(10, 15)
p
25
8
1
C
r
5
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Achieving Multiple Goals
q
g
A
B
(10, 15)
(10, 15)
p
1
C
r
5
(3, 3)
E
g
(2, 2)
D
s
t
(1, 5)
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Goal Annotation
g
g
q
g
A
B
(10, 15)
(10, 15)
p
g
1
C
r
5
g
(3, 3)
E
g
(2, 2)
D
s
t
g
g
(1, 5)
g
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Just in Case (JIC) Planning
?
?
?
?
1. Seed plan 2. Identify best branch
point 3. Generate a contingency branch 5.
Evaluate Integrate the branch
Construct plangraph Back-propagate value
tables Compute gain Select branch condition
goals
Vm
Vb
r
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Estimating Branch Value
V1
V
r
Max
V2
V
r
V3
V
r
V4
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Plan Statistics
resource probability
plan value function
P
Vm
r
r
V1
V2
V3
V4
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Expected Branch Gain
P
r
V1
V2
V3
V4
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Selecting the Branch Condition
branch condition
branch condition
P
r
V1
V2
V3
V4
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Selecting Branch Goals
branch goals
g1
P
g3
r
r
V1
g1
V2
g3
V3
V4
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Evaluating the Branch
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1. Seed plan 2. Identify best branch
point 3. Generate a contingency
branch 4. Evaluate integrate the branch
Compute value function Compute actual gain
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Actual Branch Gain
P
actual branch condition
Vm
Vb
r
r
Branch value function
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Remarks Single Plangraph
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1. Seed plan 2. Identify best branch
point 3. Generate a contingency branch 5.
Evaluate Integrate the branch
Construct plangraph Back-propagate value
tables Compute gain Select branch condition
goals
Vm
Vb
r
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Plan Graph
V1
g1
r
V2
g2
r
V3
g3
r
V4
g4
r
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Branch Initial Conditions
p
v
r
q,r
v
r
v
r
p,r
v
v
r
r
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Single Plangraph
Construct single plangraph Back-propagate value
tables
1. Seed plan 2. Identify best branch
point 3. Generate a contingency
branch 4. Evaluate integrate the branch
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Discharge conditions Compute gain Select branch
condition goals
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Issues
Sensor costs Setup steps Utility updates Floating
contingencies
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The End.