ePlanSys

ePlanSys is an epistemic planning system for ROS 2. It extends PlanSys2 with planning and execution for agents that do not know everything about their environment: domains where an action’s precondition may be a statement about what an agent knows, and where what to do next depends on what a sensing action turned out to observe.

A classical PlanSys2 plan is a sequence. Every action’s preconditions are known to hold when its turn comes, so there is nothing to decide at run time. Under partial observability that no longer holds, and the solution to a planning problem is a policy: a tree whose branches are the possible observations. The packages documented here add the pieces that produce such a policy, execute it, and keep a model of what the agents know while it runs.

The classical PlanSys2 packages are included here with their upstream commit history, and their documentation is the PlanSys2 web page. All of them have been modified: the extension points the epistemic packages attach to were widened, compatibility shims were added for Humble and Rolling, and defects found while running the system were corrected. NOTICE records the package origins and the categories of modification.

Packages

Package

Contents

plansys2_epistemic_planner

The plansys2/EpistemicPlanSolver plan solver plugin: the Kripke state representation, DEL product update, bisimulation contraction, heuristics, search strategies, and the selection policy that picks between them.

plansys2_epddl_grounder

The EPDDL front end: it runs the plank toolkit as a subprocess to turn a domain and problem pair into the grounded task the planner and the epistemic state search over, and caches the result.

plansys2_epistemic_msgs

The six service definitions of the epistemic state: LoadTask, CheckFormula, ApplyAction, GetGoal, SetGoal and Announce.

plansys2_epistemic_executor

The policy representation, its rendering as a behavior tree, the four epistemic behavior tree nodes, and the epistemic_state node that holds the model those nodes consult.

plansys2_epistemic_bt_builder

The plansys2::EpistemicBTBuilder plugin for plansys2_executor, kept in its own package because it is the only piece that depends on the executor.

plansys2_epistemic_perception

The epistemic_perception node: named regions of an occupancy grid, classified as clear, blocked or undecided, and reported to the epistemic state as the outcome of a sensing action or as a public announcement.

plansys2_aletheia_plan_solver

An alternative plan solver plugin that runs the same planner as an external process instead of in process, for deployments where the planner binary is built and versioned separately.

plansys2_tui_cli

The command line front end: the ros2 plansys2 verbs, among them epistemic, which is the terminal for what the agents know, and a four-quadrant Textual dashboard over the running system.

eplansys_demo

Runnable missions. The corridor demo needs no simulator and no hardware, so a clone of this repository can execute an epistemic policy with one command. See Demos.

eplansys

A metapackage that installs PlanSys2 and all of the above as one unit. It builds nothing itself.

Contents

Getting started

Concepts

Demos

Tutorials

Open-RMF execution

Reports

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