NODE kb_interface

services for read/write on the rosplan kb

This node exposes, as ROS service, some important functionalities for performing the replanning.

Its role is mostly to hide the specificiy of some corrections on the knowledge base, due to the structure of the PDDL model in use for this project.

Authors: Francesco Ganci
Version: v1.0

Note

It supports the develop mode: waitkey, develop print

Defines

NODE_NAME

LOGSQUARE(str)

OUTLABEL

TLOG(msg)

TWARN(msg)

TERR(msg)

DEVELOP_MODE

DEVELOP_PRINT

WTLOG(msg)

WTWARN(msg)

WTERR(msg)

DEVELOP_WAIKEY

WAITKEY

SERVICE_REPLAN

SERVICE_UPDATE_GOAL

LANDMARK_REPLAN

LANDMARK_COLLECT

LANDMARK_SOLVE

Functions

void shut_msg(int sig)

int main(int argc, char *argv[])

Variables

ros::ServiceServer *srv_replan

ros::ServiceServer *srv_update_goal

class predicate_instance

representation of a predicate

This simple data structure is used for handling the predicates in a more convenient way.

Todo:: this class should be better designed, or, even better, included into the currently available framework for the knowledge base.

Public Functions

inline void set_param(std::string p1, std::string val1): insert one param

inline void set_param_2(std::string p1, std::string val1, std::string p2, std::string val2): insert two params

Public Members

std::string name = "": name

std::map<std::string, std::string> params: parameters

bool default_value = false: default value

class kb_interface : private kb_tools 

Implementation of the node kb_interface as class.

The node provides a general service for replanning, as well as some utilities taking into account the particularities of the landmarks with respect to the structure of the PDDL model.

Todo:: the node should read the waypoints from the PDDL model; currently, the waypoints are hardcoded in the constructor.

Todo:: the topology of the problem can be better handled by this node.

Public Functions

inline kb_interface()

kb_interface node constructor

The constructor allocates the most relevant predicates of the PDDL model and their default values. These values are used when a landmark, or a replanning, is required by another node.

Todo:: the node should read the waypoints from the PDDL model; currently, the waypoints are hardcoded in the constructor.

inline bool cbk_replan(std_srvs::Empty::Request &req, std_srvs::Empty::Response &res)

implementation of the replan service

the service first of all restores the most relelvand values of the PDDL model inside the ontology, then adjusts the informations regarding the topological localisation in a way such that the only place explored is the one where the robot is currently.

Parameters

request – (empty)
response – (empty)

inline bool cbk_update_goal(robocluedo_rosplan_msgs::UpdateGoal::Request &req, robocluedo_rosplan_msgs::UpdateGoal::Response &res)

implementation of service for updating goals

Purpose of this service is to create the proper conditions in order to apply one of the three available landmarks: REPLAN, COLLECT and SOLVE.

“REPLAN” simply sets the “dirty” flags in a way such that the plan, when found, is going to start with the (replan ) PDDL action. The localisation is not affected, or at least not by this node.

“COLLECT” causes the node to look for a still unexplored waypoint. if all the waypoints have been explored, the node refuses the request, otherwise it sets the first available waypoint. The command doesn’t allow to decide which waypoint the robot can explore: the waypoint is choosen automatically by this node.

“SOLVE” only sets the “dirty” flags as the “REPLAN” landmark does, but in a way such that the system has to necessairly call the PDDL action (solve ?wp) after moved to the center of the arena.

Attention: the request is rejected with no effect on the knowledge base if the requested landark is not applicable. It could happen for instance when the robot has explored every single waypoint.

Note

in any case, the goal is cancelled, hence a failure in applying one unapplicable landmark requires to set again one more landmark.

Parameters

request – it communicates the landmark to set
response –

Private Members

ros::NodeHandle nh

std::vector<predicate_instance> init_pred: a list of init predicates

std::vector<predicate_instance> goal_pred: a list of goal predicates

std::vector<std::string> wps: list of waypoints