rp_example

rp_action examples

This folder contains a full example of PNP application using ROS actions. It is suggested to run these examples in the docker containers. Follow instructions in PetriNetPlans/docker to build a docker image and run a docker container containing this example.

Organization of the folders:

• rp_action and rp_action_msgs: implementation of basic actions (no PNP code)
• rp_pnp: plans and scripts to run plans (PNP ActionServer code)
• rp_demo: overall demo launch

Link and compile rp_action packages

- Note: not needed if you are using the docker image. -

Make sure PNP and PNPros have been installed and build ROS packages in this folder.

Example:

    cd ~/ros/catkin_ws/src
    ln -s $HOME/src/PetriNetPlans/PNPros/examples/rp_example/rp_action . 
    ln -s $HOME/src/PetriNetPlans/PNPros/examples/rp_example/rp_action_msgs . 
    ln -s $HOME/src/PetriNetPlans/PNPros/examples/rp_example/rp_pnp . 
    ln -s $HOME/src/PetriNetPlans/PNPros/examples/rp_example/rp_demo .
    cd ..
    catkin_make

Single robot execution

Start the demo

    roscd rp_demo/scripts
    ./start_demo.bash 

Run a plan

    roscd rp_pnp/scripts
    ./runplan.bash sequence_loop

Other plans to test available in rp_pnp/plans folder.

Stop the current plan

    roscd rp_pnp/scripts
    ./runplan.bash stop

Multi-robot execution

NOTE: Multi-robot configuration not working yet on ROS Melodic (Ubuntu 18.04)!

Start the demo

    roscd rp_demo/scripts
    ./start_demo.bash  multirobot

Run a plan for each robot

    roscd rp_pnp/scripts
    ./runplan.bash robot_0 sequence_loop
    ./runplan.bash robot_1 sequence_loop

Stop the current plan for each robot

    roscd rp_pnp/scripts
    ./runplan.bash robot_0 stop
    ./runplan.bash robot_1 stop

Plans available

Plans available in rp_pnp\plans folder: sequence_loop, sensing, interrupt, fork_join.

sequence_loop

sensing

interrupt

fork_join

multi_robot

Notes: 1) the obstacle condition can be activated by placing (drag with mouse) the red box in the simulated environment in front of the robot; 2) the wave action outputs some text on the screen.

Quit the simulation

    rosnode kill -a

Implementation details

The devlopment of a PNP-based application requires two components:

• domain-independent plan execution monitor pnp_node ROS node
• a plan to be executed <plan>.pnml
• a domain-specific PNP Action Server implementing actions and conditions that will be used by the PNP plan execution monitor

The PNP Action Server is a ROS node inheriting from the domain-independent class PNPActionServer defined in PNPros package (see PNPActionServer.h).

Example:

    // definition of action functions

    void action_fn(string params, bool *run) {
      ...
      while ( ... && (*run)) {
        ...
      }
    }

    // definition of condition functions

    int condition_fn(string params) {
      int r = ...; // 0: false, 1: true, -1: unknown
      return r;
    }
    

    // PNP Action server

    class MyPNPActionServer : public PNPActionServer {

      public:

        MyPNPActionServer() : PNPActionServer()  { 
        
          register_action("action",&action_fn);
          ...
          register_condition("condition",&condition_fn);
          ...
        }

    };