sensors

Line-tension sensing: HX711 load cell on hardware, MuJoCo FTS in simulation.

• Build type: ament_python

• Version: 0.0.0

• License: MIT

• Maintainer(s): nzge

• Source: src/sensors/

Executables

Command (ros2 run)	Target
ros2 run sensors load_cell_publisher	sensors.load_cell_publisher:main

Launch files

sensor.launch.py

ros2 launch sensors sensor.launch.py

Launch argument	Default	Description
source	hardware

_{Source: sensors/launch/sensor.launch.py}

Parameters & configuration

sensor_params.yaml

Node load_cell_node

Parameter	Default	Type
arduino_port	'/dev/ttyACM0'	str
arduino_baud	9600	int
arduino_timeout_s	0.05	float
tare_on_start	True	bool
tare_samples	20	int
sensor_sign	1.0	float
sensor_line_filter_window	2	int
calibration_offset	0.0	float
calibration_scale	4.8e-05	float
use_moving_average	True	bool
window_size	10	int
publish_frequency	80.0	float
tension_max_threshold	20.0	float
noise_floor	0.1	float
frame_id	'rod_tip_link'	str
target_tension	3.5	float
sim_line_stiffness	220.0	float
sim_line_springlength	0.2	float
sim_line_damping	1.5	float
sim_rod_frame	'rod_tip_link'	str
sim_fish_frame	'fish_link'	str

Full file

# Configuration for the Fishing Arm Load Cell (HX711 via Arduino serial).
load_cell_node:
  ros__parameters:
    # --- Arduino serial (matches project_w_t_controller.ipynb) ---
    arduino_port: "/dev/ttyACM0"
    arduino_baud: 9600
    arduino_timeout_s: 0.05
    tare_on_start: true
    tare_samples: 20
    sensor_sign: 1.0
    sensor_line_filter_window: 2

    # --- Physical calibration ---
    # Used when tare_on_start=false; overwritten by live tare otherwise.
    calibration_offset: 0.0
    # N per raw ADC count. Notebook used 4.8e-5; tune on your rig.
    calibration_scale: 0.000048

    # --- Signal processing ---
    use_moving_average: true
    window_size: 10
    publish_frequency: 80.0

    # --- Safety / operational limits ---
    tension_max_threshold: 20.0
    noise_floor: 0.1

    frame_id: "rod_tip_link"
    target_tension: 3.5

    # --- Simulation stretch model (must match fishing-robot_sim.xml tendon) ---
    sim_line_stiffness: 220.0
    sim_line_springlength: 0.20
    sim_line_damping: 1.5
    sim_rod_frame: "rod_tip_link"
    sim_fish_frame: "fish_link"

_{Source: sensors/config/sensor_params.yaml}

Dependencies

• Runtime: geometry_msgs interfaces python3-serial rclpy std_msgs tf2_ros

• Test: ament_copyright ament_flake8 ament_pep257 python3-pytest

Python API

Full module/class/function reference for sensors is generated automatically:

• sensors