DOCS – HOW TO use RoboCLuedo aRMOR interface

the interface provides 4 main directives:

• ADD – put a hint into the aRMOR ontology

• FIND – find the hypotheses which are CONSISTENT (i.e. COMPLETE but not INCONSISTENT)

• DEL – mark a hypothesis as wrong, i.e. discard it

• BACKUP – save the ontology on file.

services schematics

ADD – register a new hint into the Ontology

To add a new hint (from the Oracle?) the node provides the service /cluedo_armor/add_hint of type robocluedo_armor_msgs/AddHint.

Note that adding the same hint twice doesn’t affect the content of the ontology. The request will retur true even in this case.

here’s the format of the service:

## file 'AddHint.srv'
# it represents a hint of the type -> (Aelem, Belem):property

# the numeric ID of the hint
int32 hypID

# fields of the property
string property
string Belem

---

bool success

fields:

• hypID is the integer identifier of the hypothesis ID

• property indicates the role to define: it corresponds to the ‘key’ element of the hint message

• Belem is the content of the property: it corresponds to the field value from the Oracle

the ontology allows to define three roles: (Aelem is always the label of the hypothesis, whereas Belem is the value of the property)

• (who "HP<hypID>" ?Belem)

• (where "HP<hypID>" ?Belem)

• (what "HP<hypID>" ?Belem)

very important: the node allows only these properties! it will raise an error if the property hasn’t one of the abovementioned keys; remember to check the success flag of the message.

property names must be written in lowercase!

FIND – ask for a consistent hint

the service /cluedo_armor/find_consistent_h of type robocluedo_armor_msgs/FindConsistentHypotheses is what you need to ask the Ontology for a admissible solution.

here’s the service file employed by the service:

## file 'FindConsistentHypotheses.srv'

# empty request

---

# list of consistent hypotheses from the ontology
Hypothesis[] hyp

when called, the service returns the entire list of the hypotheses belonging to the COMPLETED set and not belonging to the INCONSISTENT one. Remember that the ontology has the following structure:

• THINGs – owl:thing

  • HYPOTHESIS – (what only WEAPON) and (where only PLACE) and (who only PERSON)

    • COMPLETED – (what min 1 WEAPON) and (where min 1 PLACE) and (who min 1 PERSON)

      • INCONSISTENT – (what min 2 WEAPON) or (where min 2 PLACE) or (who min 2 PERSON)

  • WHO

  • WHERE

  • WHAT

Hence the COMPLETED set will contain not only the complete hypotheses, but also the INCONSISTENT ones. The service performs a set difference COMPLETED - INCONSISTENT which is the set of the admissible solutions, if any.

don’t forget to check the length of the list! The method could return a empty list of complete hypotheses.

here’s the type robocluedo_armor_msgs/Hypothesis:

## file 'Hypothesis.msg'

# DEPRECATED
string tag

# the integer identifier of the hypothesis (-1 if the identifier is not standard)
int32 ID

# who killed Dr. Black
string who
# where the murder happened
string where
# what is the murder weapon
string what

DEL – discard a hypothesis

use the service /cluedo_armor/wrong_hypothesis of type robocluedo_armor_msgs/DiscardHypothesis, whose structure is reported here below:

## file 'DiscardHypothesis.srv'

int32 ID

---

bool success

the request could fail due to, for instance, the unexistence of the indicated hypothesis.