YASMIN (Yet Another State MachINe)

YASMIN is a project focused on implementing robot behaviors using Finite State Machines (FSM). It is available for ROS 2, Python and C++.

Table of Contents

1. Features
2. Installation
3. Demos
   • Python
   • Cpp
4. YASMIN Viewer

Features

• Fully integrated into ROS 2.
• Available for Python and C++.
• Fast prototyping.
• Default states for ROS 2 action and service clients.
• Blackboards are used to share data between states and state machines.
• State machines can be canceled and stopped, which means stopping the current executing state.
• A web viewer is included, which allows monitoring of the execution of the state machines.

Installation

$ cd ~/ros2_ws/src
$ git clone git@github.com:uleroboticsgroup/simple_node.git
$ git clone git@github.com:uleroboticsgroup/yasmin.git
$ cd yasmin
$ pip3 install -r requirements.txt
$ cd ~/ros2_ws
$ colcon build

Demos

A Python and a C++ demo are included.

Python

#!/usr/bin/env python3

import time
import rclpy

from simple_node import Node

from yasmin import State
from yasmin import StateMachine
from yasmin_viewer import YasminViewerPub


# define state Foo
class FooState(State):
    def __init__(self):
        super().__init__(["outcome1", "outcome2"])
        self.counter = 0

    def execute(self, blackboard):
        print("Executing state FOO")
        time.sleep(3)

        if self.counter < 3:
            self.counter += 1
            blackboard.foo_str = "Counter: " + str(self.counter)
            return "outcome1"
        else:
            return "outcome2"


# define state Bar
class BarState(State):
    def __init__(self):
        super().__init__(outcomes=["outcome3"])

    def execute(self, blackboard):
        print("Executing state BAR")
        time.sleep(3)

        print(blackboard.foo_str)
        return "outcome3"


class DemoNode(Node):

    def __init__(self):
        super().__init__("yasmin_node")

        # create a state machine
        sm = StateMachine(outcomes=["outcome4"])

        # add states
        sm.add_state("FOO", FooState(),
                     transitions={"outcome1": "BAR",
                                  "outcome2": "outcome4"})
        sm.add_state("BAR", BarState(),
                     transitions={"outcome3": "FOO"})

        # pub
        YasminViewerPub(self, "YASMIN_DEMO", sm)

        # execute
        outcome = sm()
        print(outcome)


# main
def main(args=None):

    print("yasmin_demo")
    rclpy.init(args=args)
    node = DemoNode()
    node.join_spin()
    rclpy.shutdown()


if __name__ == "__main__":
    main()

Cpp

#include <