sas_force_sensor

Tip

Repository for this module: https://github.com/MarinhoLab/sas_force_sensor.
More information about SmartArmStack is available at https://smartarmstack.github.io/.

Contents

• include/ — public C++ headers.
• src/ — library and pybind11 bindings.
• sas_force_sensor/ — Python package (thin wrapper around the pybind11 module).
• scripts/ — Python example script.
• launch/ — example launch file for the sinusoidal force sensor node.
• config/ — example parameter configuration file.

ROS 2 Nodes & Parameters

The package is primarily a library. It also provides one example node.

Node: sinusoidal_force_sensor

Property	Value
Executable	sinusoidal_force_sensor
ROS node name	sinusoidal_force_sensor (set by the name launch argument of sinusoidal_force_sensor_launch.py)
Description	Example node that publishes a sinusoidal force/torque wrench on <node_name>/get/wrench via ForceSensorServer.

Parameters

The node currently declares no ROS parameters — the amplitude, frequency, and tick rate are hardcoded constants in src/examples/sinusoidal_force_sensor.cpp.

Sample launch

ros2 launch sas_force_sensor sinusoidal_force_sensor_launch.py

The launch file loads the (currently empty) parameter block from config/config.yaml (override with config_file:=/path/to/config.yaml) so the node follows the standard SmartArmStack config-file pattern.

Client–Server pair

The package implements a ForceSensorServer / ForceSensorClient pair that manages a single geometry_msgs/msg/WrenchStamped topic, <topic_prefix>/get/wrench.

• sas::ForceSensorServer is used by the process that has access to the physical (or simulated) force/torque sensor. It publishes the readings.
• sas::ForceSensorClient is used by any other process that needs to consume the force/torque readings. It subscribes to the topic.

Both classes take a shared rclcpp::Node and a topic_prefix string that forms the namespace for the topic. When topic_prefix is "GET_FROM_NODE" (the default) the node name is used automatically.

Force and torque readings are exposed as dqrobotics::DQ pure quaternions, which is a suitable and consistent representation across the SmartArmStack ecosystem.

Header files

Class	Header
sas::ForceSensorServer	sas_force_sensor/sas_force_sensor_server.hpp
sas::ForceSensorClient	sas_force_sensor/sas_force_sensor_client.hpp

Importing in Python

from sas_force_sensor import (
    ForceSensorServer,
    ForceSensorClient
)

Script

Demonstrates ForceSensorServer and ForceSensorClient in Python.

ros2 run sas_force_sensor sas_force_sensor_interface_example.py

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