Problem Expert

The Problem Expert module is responsible for maintaining the instances, predicates and goals of the PDDL problem.

The main class is plansys2::ProblemExpertNode, which is instantiated from ProblemExpertNode.cpp. plansys2::ProblemExpertNode is a rclcpp_lifecycle::LifecycleNode, but currently the functionality is in the active phase.

The class responsible for maintaining this problem instance is plansys2::ProblemExpert, which is independent of ROS2.

The Problem Expert is dynamic and volatile, accessing its functionality through ROS2 services. To facilitate the task of the application developer, an plansys2::ProblemExpertClient class has been implemented that hides the complexity of handling ROS2 messages and services. Its API is similar to that of plansys2::ProblemExpert, since both have to implement the plansys2::ProblemExpertInterface interface.

The Problem Expert instantiates a plansys2::DomainExpertClient, and every update query is verified against domain to check if it is valid.

Every update in the Problem, is notified publishing a std_msgs::msg::Empty in /problem_expert/update_notify. It helps other modules and applications to be aware of updates, being not necessary to do polling to check it.

Services

• /problem_expert/add_problem_function [plansys2_msgs::srv::AffectNode]
• /problem_expert/add_problem_goal [plansys2_msgs::srv::AddProblemGoal]
• /problem_expert/add_problem_instance [plansys2_msgs::srv::AffectParam]
• /problem_expert/add_problem_predicate [plansys2_msgs::srv::AffectNode]
• /problem_expert/clear_problem_knowledge [plansys2_msgs::srv::ClearProblemKnowledge]
• /problem_expert/exist_problem_function [plansys2_msgs::srv::ExistNode]
• /problem_expert/exist_problem_predicate [plansys2_msgs::srv::ExistNode]
• /problem_expert/get_problem [plansys2_msgs::srv::GetProblem]
• /problem_expert/get_problem_function [plansys2_msgs::srv::GetNodeDetails]
• /problem_expert/get_problem_functions [plansys2_msgs::srv::GetStates]
• /problem_expert/get_problem_goal [plansys2_msgs::srv::GetProblemGoal]
• /problem_expert/get_problem_instance [plansys2_msgs::srv::GetProblemInstanceDetails]
• /problem_expert/get_problem_instances [plansys2_msgs::srv::GetProblemInstances]
• /problem_expert/get_problem_predicate [plansys2_msgs::srv::GetNodeDetails]
• /problem_expert/get_problem_predicates [plansys2_msgs::srv::GetStates]
• /problem_expert/is_problem_goal_satisfied [plansys2_msgs::srv::IsProblemGoalSatisfied]
• /problem_expert/remove_problem_function [plansys2_msgs::srv::AffectNode]
• /problem_expert/remove_problem_goal [plansys2_msgs::srv::RemoveProblemGoal]
• /problem_expert/remove_problem_instance [plansys2_msgs::srv::AffectParam]
• /problem_expert/remove_problem_predicate [plansys2_msgs::srv::AffectNode]
• /problem_expert/update_problem_function [plansys2_msgs::srv::AffectNode]

Published topics

• /problem_expert/update_notify [std_msgs::msg::Empty]

Changelog for package plansys2_problem_expert

1.0.10 (2021-07-03)

• Remove node parameter in client constructors
• Adding comments specifying how the syntax is wrong in unexpected_syntax problem file.
• Adding unit tests for new functions in plansys2_problem_expert.
• Add ability to read in pddl problem files to plansys2 and a new AddProblem service to the plansys2_problem_expert. Adding problem_file node parameter to plansys2_problem_expert to load a single problem file at launch.
• ros2-plan-msg: Adding functions to plansys2_msgs/Knowledge message.
• pddl-tree-messages: Deleting unused function declarations. Adding explicit specifier to single param constructors in plansys2_core/Types.hpp.
• Suggestion for #118
• pddl-tree-messages: Extending action string parsing utilities in plansys2_problem_expert/Utils.cpp.
• pddl-tree-messages: Performing some minor cleanup.
• pddl-tree-messages: Using explicit specifier for single parameter constructors in plansys2_core/Types.hpp.
• pddl-tree-messages: Replacing user access function calls with shorter versions where possible.
• pddl-tree-messages: Adding user access functions to domain expert client.
• pddl-tree-messages: Adding goal user access functions to problem expert client.
• pddl-tree-messages: Adding predicate user access functions to problem expert client.
• pddl-tree-messages: Adding predicate user access functions to problem expert client.
• pddl-tree-messages: Using helper functions in problem expert client to handle user interactions.
• pddl-tree-messages: Updating getInstance and getInstances calls to use helper classes.
• pddl-tree-messages: Updating addInstance and removeInstance calls to use helper classes.
• pddl-tree-messages: Replacing hard coded node equality check with function call.
• pddl-tree-messages: Using ROS messages to define the PDDL construct trees.
• Adding support for PDDL addition and subtraction expressions. Courtesy of \@jjzapf
• Update version
• Contributors: Alexander Xydes, Francisco Mart