TL-SHOP Derek MonnerNat Ayewah [email protected]@cs.umd.edu CMSC 722 Term Project, Spring...
-
Upload
katelyn-burke -
Category
Documents
-
view
212 -
download
0
Transcript of TL-SHOP Derek MonnerNat Ayewah [email protected]@cs.umd.edu CMSC 722 Term Project, Spring...
![Page 1: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/1.jpg)
TL-SHOP
Derek Monner Nat Ayewah
[email protected] [email protected]
CMSC 722 Term Project, Spring 2007University of Maryland, College Park
Temporal Logic Control Rules in a Hierarchal Task Network Planner
![Page 2: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/2.jpg)
Hierarchal Task Network (HTN) Planning
“What you can do”
Task:
Method: taxi-travel(x,y)
get-taxi ride(x,y) pay-driver
travel(x,y)
Method: air-travel(x,y)
travel(a(y),y)get-ticket(a(x),a(y))
travel(x,a(x))fly(a(x),a(y))
![Page 3: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/3.jpg)
Temporal Logic Control Rules
“What you cannot do”
![Page 4: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/4.jpg)
Methodology
Augment JSHOP2 with TLPlan strategy TL-SHOP is backwards compatible with JSHOP2
Prune plans when application of an operator creates a state that violates an LTL constraint
Provide additional syntax and parsing rules for specifying LTL control rules
![Page 5: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/5.jpg)
Domain Specification
Operator…(constraint)
Operator…(constraint)
Method…
(constraint)
Method…
(constraint)
Constraint
Constraint
Problem
Constraint
Problem
Constraint
1 2
3
Control Rule Specification
![Page 6: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/6.jpg)
(1) Domain Control Rules Like one would expect
(2) Problem Control Rules Allows easy creation of “customized subdomains”
(3) Method/Operator Postconditions When operator or method is applied, its
postcondition is added to the set of applicable control rules for all descendant states in the search tree
Control Rule Specification
![Page 7: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/7.jpg)
Extending the Parser
Use the same syntax in all three locations(:contraint LTLExpression)
Four other new keywords::next
:always
:eventually
:until
![Page 8: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/8.jpg)
Extending the Parser Recursive Definition
LTLExpression :=
AND (LP LTLExpression RP)+
| OR (LP LTLExpression RP)+
| NOT LTLExpression
| IMPLY LP LTLExpression RP LP LTLExpression RP
| :next LTLExpression
| :always LTLExpression
| :eventually LTLExpression
| :until LP LTLExpression RP LP LTLExpression RP
| LP forall (Variables) LTLAtom LTLExpression RP
| LP exists (Variables) LTLAtom LTLExpression RP
![Page 9: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/9.jpg)
Extending the Parser
Examples(:contraint (:always (on ?a ?b)))
(:contraint (:always
(forall (?x) (isPhDStudent ?x)
(:eventually (isRich ?x))
)
)
![Page 10: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/10.jpg)
LTL Inference Engine
![Page 11: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/11.jpg)
LTL Inference Engine
Progress function is called every time operator is applied Evaluates rules in current state Derives rules to be applied to next state
When a plan is found, check remaining control rules for eventually clauses If they exist, plan might be invalid!
![Page 12: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/12.jpg)
Limitations
Evolution of LTL Rules via Progress function seems to be inherently dynamic Requires memory allocation during planning!
As a result, performance on large problems is significantly worse than JSHOP2
![Page 13: TL-SHOP Derek MonnerNat Ayewah dmonner@cs.umd.eduayewah@cs.umd.edu CMSC 722 Term Project, Spring 2007 University of Maryland, College Park Temporal Logic.](https://reader036.fdocuments.us/reader036/viewer/2022082917/55140de0550346e7488b4edd/html5/thumbnails/13.jpg)
Conclusion
LTL Control Rules can be used in many ways to prune search space in HTN planning
Increases expressiveness of domain and problem descriptions
Source code available at:http://code.google.com/p/tl-shop