SM Simple Action Client

A SMACC2 tutorial demonstrating topic subscription and action client patterns.

Overview

This state machine demonstrates:

• Topic Subscriber Pattern: ClModeSelect subscribes to /mode_command
• Action Client Pattern: ClFibonacci sends goals to Fibonacci action server
• Three-State Flow: Demonstrates waiting → executing → completion states

State Machine Architecture

States

StState1 - Waiting for Mode Command

• Purpose: Initial state, waits for autonomous mode trigger
• Orthogonals:
  • OrModeSelect: Runs CbModeSelect behavior (subscribes to /mode_command)
  • OrFibonacci: Empty (no behavior)
• Transitions:
  • EvAutonomousMode (when data=1) → StState2

StState2 - Executing Fibonacci Action

• Purpose: Sends Fibonacci calculation request to action server
• Orthogonals:
  • OrModeSelect: Runs CbModeSelect behavior (still monitoring topic)
  • OrFibonacci: Runs CbFibonacci behavior (sends goal with order=10)
• Transitions:
  • EvCbSuccess → StState3 (action succeeded)
  • EvCbFailure → StState2 (stay in state to retry)
  • EvManualMode (when data=0) → StState1

StState3 - Action Completed Successfully

• Purpose: Terminal success state, demonstrates completion
• Orthogonals:
  • OrModeSelect: Runs CbModeSelect behavior (still monitoring topic)
  • OrFibonacci: Empty (no behavior)
• Transitions:
  • EvManualMode (when data=0) → StState1 (restart cycle)

Interaction Pattern

Start
  ↓
┌─────────────────┐
│   StState1      │ ← Manual: publish {data: 0}
│   (Waiting)     │ ←──────────────────────┐
└────────┬────────┘                        │
         │ Auto/Manual: {data: 1}          │
         ▼                                 │
┌─────────────────┐                        │
│   StState2      │                        │
│   (Executing)   │                        │
└─────┬───┬───────┘                        │
      │   │                                │
      │   └─ Failure (retry in StState2)  │
      │                                    │
      ▼ Success                            │
┌─────────────────┐                        │
│   StState3      │                        │
│   (Complete)    │                        │
└─────────────────┘                        │
      │                                    │
      └────────────────────────────────────┘

Build Instructions

First, source your ROS2 installation:

source /opt/ros/jazzy/setup.bash

Before you build, install dependencies:

rosdep install --ignore-src --from-paths src -y -r

Build with colcon:

colcon build --packages-select sm_simple_action_client

Operating Instructions - Automated Demo

The launch file starts everything automatically for a hands-off demonstration:

source install/setup.bash
ros2 launch sm_simple_action_client sm_simple_action_client.py

What happens automatically:

1. Fibonacci action server starts in separate konsole window
2. State machine starts in StState1 in separate konsole window
3. Auto-trigger waits 3 seconds, then publishes autonomous mode command
4. State machine transitions: StState1 → StState2
5. Fibonacci action executes (order=10)

File truncated at 100 lines see the full file

Changelog for package sm_simple_action_client

3.0.2 (2025-11-19)

• Complete self-contained demo implementation with 3-state workflow
  • Added StState3 success completion state with informative onEntry message
  • Created auto_mode_trigger.py script for automatic demo initialization
  • Implemented comprehensive Python launch file with logging infrastructure
  • Added Fibonacci action server to launch configuration
  • Updated state transitions: StState2 now transitions to StState3 on action success
  • Fixed auto-trigger shutdown sequence to prevent TypeError on exit
  • Optimized Fibonacci action order from 100 to 10 for faster demo completion
  • Added timestamped log directory creation with fallback error handling
  • Integrated konsole terminal support for multi-window process visualization
  • Removed outdated XML launch file (sm_simple_action_client.launch)
  • Comprehensive README documentation covering:
    • State machine architecture with 3-state flow diagram
    • Automated demo and manual control instructions
    • Monitoring commands and troubleshooting guide
    • Component reference for clients, behaviors, and orthogonals
    • Learning objectives for SMACC2 patterns
• Bug fixes:
  • Fixed config file path to use correct simple_action_client_example_config.yaml
  • Resolved rclpy shutdown race condition in auto_mode_trigger
  • Updated all documentation references from order=100 to order=10
• Contributors: Claude Code, brettpac

2.3.19 (2025-06-17)

• simple state machine with an action client and a topic subscriber (#543)

  • create a simple state machine with two states, one action server client and one subscriber client
  • added the template copyright and license info to all code files
  • renamed package and files to fit the established naming convention
  • added missing license for mode_selection_client and orhtogonals files
  • moved license to the top of the cl_mode_select.hpp file

  * fixed formatting errors ---------Co-authored-by: Sukhraj Klair <<sukhraj.k@radskunkworks.com>>

• Contributors: sukhrajklair

2.4.1 (2023-07-06)

2.3.16 (2023-07-16)

2.3.18 (2023-04-24)

2.3.8 (2023-03-12 21:50)

2.3.7 (2023-03-12 21:45)

2.3.6 (2023-03-12 20:30)

2.3.5 (2023-03-07 00:14)

2.3.4 (2023-03-07 00:02)

2.3.3 (2023-03-02 22:58)

2.3.2 (2023-03-02 22:22)

2.3.1 (2022-11-28)

1.22.1 (2022-11-09 20:22)

1.22.0 (2022-11-09 19:53)