Low-Pass-Force-Torque-Sensor-Controller

The Low-Pass-Force-Torque-Sensor-Controller is a ROS package designed to facilitate the control of force-torque sensors using the ros_control framework. It includes an integrated low-pass filter to enhance the accuracy of the sensor readings. This controller is an extension of the original ros_controllers repository, featuring specific modifications to expand its capabilities.

Changes and Features

• Added a first-order Butterworth low-pass filter to the controller. This filter is applied to the sensor's raw force-torque data. In addition to the unfiltered wrench data, the filtered wrench data is published on the <ft-sensor-name>_filtered topic.
• The strength of the low-pass filter can be adjusted dynamically using the dynamic reconfigure feature. Increasing the filter coefficient value results in more noise being filtered out from the sensor readings.
• The original force_torque_sensor_controller published all wrenches available in the ROS hardware interface. The low_pass_force_torque_sensor_controller has been modified to publish a single wrench, which is specified using the name parameter.

Integration

To integrate the low-pass force-torque sensor controller into your ros_control configuration, follow these steps:

1. Examine the example configuration and launch files provided in the following locations:

   • Configuration YAML: config/low_pass_force_torque_sensor_controller.yaml
   • Launch File: launch/low_pass_force_torque_sensor_controller.launch

2. Configuration YAML (config/low_pass_force_torque_sensor_controller.yaml):

low_pass_force_torque_sensor_controller:
  type: force_torque_sensor_controller/LowPassForceTorqueSensorController  # Specify the controller type as LowPassForceTorqueSensorController
  name: wrench  # Specify the name of the force torque sensor interface to be published
  low_pass_filter_coeff: 500 # coefficient for filter strength, higher value -> more filtering 
  publish_rate: 50  # Specify the rate (in Hz) at which the controller publishes data

3. Launch File (launch/low_pass_force_torque_sensor_controller.launch):

<?xml version="1.0"?>
<launch>
  <!-- Load configuration -->
  <rosparam command="load" file="$(find low_pass_force_torque_sensor_controller)/low_pass_force_torque_sensor_controller.yaml" />
  <!-- Spawn controller -->
  <node name="low_pass_force_torque_sensor_controller_spawner" pkg="controller_manager" type="spawner" output="screen" args="low_pass_force_torque_sensor_controller" />
</launch>

Dynamic Reconfigure

To modify the behavior of the controller using dynamic reconfigure:

1. Launch the ROS rqt_gui tool by executing rosrun rqt_gui rqt_gui.

2. Within rqt_gui, navigate to Plugins -> Configuration -> Dynamic Reconfigure.

3. Experiment with different values of the low-pass coefficient to observe the impact on the filtered sensor readings.

For further details and usage examples, please refer to the original ros_controllers repository.