Rokubi mini 2.0 - Force-Torque Sensor - README

Overview

This software package will provide a driver and a ROS interface for the ethercat and serial version of the rokubi mini force-torque sensor. This is at the moment just a skeleton to connect to rokubi mini devices and support the driver development of its firmware.

Authors(s): Ilias Patsiaouras, Mike Karamousadakis

Building

Installation

Building from Source

In order to use the bota_driver package, you need to download first the following dependencies:

Dependencies

• Robot Operating System (ROS) (middleware for robotics),
• soem
• ethercat_grant

Before building, you need to clone the repository and make sure that all the binary dependencies are installed. To do so, run in a terminal:

cd catkin_workspace/src
git clone https://gitlab.com/botasys/bota_driver.git
cd ../
rosdep update && rosdep install --from-path src --ignore-src -y -r
sudo apt install libxmlrpcpp-dev librosconsole-dev

Building

To build the bota_driver from source, clone the latest version from this repository into your catkin workspace and compile the package using:

1. The catkin_tools package:

	cd catkin_workspace
	catkin build bota_driver
	

1. If you don’t have the catkin_tools package, you can still build from source with catkin_make:

	cd catkin_workspace
	catkin_make --only-pkg-with-deps bota_driver
	# Don't forget to switch back to building all packages when you are done:
	# catkin_make -DCATKIN_WHITELIST_PACKAGES=""
	

1. Finally, you can build from source with catkin_make_isolated. The only difference is that each package will be processed sequentially:

	cd catkin_workspace
	catkin_make_isolated --pkg bota_driver
	

Unit Tests

No unit tests so far.

Packages

rokubimini

The core C++ library to interface one or multiple rokubimini devices. Contains abstract interfaces to start the communication.

rokubimini_ethercat

The ethercat implementation of rokubimini.

rokubimini_serial

The serial implementation of rokubimini.

rokubimini_bus_manager

An abstract class for managing a bus.

bota_node

ROS node wrapper with some convenience functions using bota_worker.

bota_worker

High resolution and threaded version of the ROS rate class.

bota_signal_handler

Contains a static signal handling helper class.

rokubimini_msgs

Contains the definitions of the ROS messages and services used for communication over ROS.

Usage

Launching

Note: The driver node sets the realtime priority to ensure the correct update rate with low jitter. Therefore your user needs rights to set this priority. If you are running the launch file as a normal user, you need to append to your /etc/security/limits.conf file the following lines (change username to your username):

username		 soft	 rtprio	  99
username		 hard	 rtprio	  99

Please log off and log in again for the changes to take effect!

Serial

If no EtherCAT device is present, the roslaunch commands with only serial devices works without root privileges provided that the user is in the dialout group. This can be done with:

sudo usermod -a -G dialout username

Please log off and log in again for the changes to take effect!

To run the sensor you can use the following command:

roslaunch rokubimini_serial rokubimini_serial.launch

EtherCAT

The EtherCAT device driver is using SOEM which requires access to certain network capabilities as it is using raw sockets, and as such any executable linking against SOEM needs to be run with certain privileges. Typically, you would run any SOEM executables with sudo or as root. This is impractical for any ROS system, and as such there exists a tool called ethercat_grant that helps with that.

If you followed the installation instruction above ethercat_grant is already installed. Alternatively, you can install it with

sudo apt install ros-<DISTRO>-ethercat-grant libxmlrpcpp-dev librosconsole-dev

and add the following launch prefix to the node tag of the rokubimini_ethercat_bus_manager_node in your launchfile

launch-prefix="ethercat_grant

Note: This launch prefix is already added to the default launch file and you can run the driver of an EtherCAT device with:

roslaunch rokubimini_ethercat rokubimini_ethercat.launch

(Alternative:) EtherCAT without launch prefix

Instead of using the ethercat_grant launch prefix, the above command to run the EtherCAT device driver can also be combined with escalated privileges (e.g. su root or sudo su, if you don’t have set a root password).

Extra launch Arguments

Niceness

If you want to change the niceness of the node, consider adding the following XML element as launch_prefix:

	<arg name="launch_prefix" default="nice -n -10" />
	...
	<node name="bus0" pkg="rokubimini_serial" type="rokubimini_serial_bus_manager_node"  output="screen" launch-prefix="$(arg launch_prefix)" required="true">

Note: If you are running the launch file as a normal user, you need to append to your /etc/security/limits.conf file the following line (change username to your username):

username - nice -20

Please log off and log in again for the changes to take effect!

GDB

For using a launch file with gdb, you need the following XML element:

  <arg name="launch_prefix_gdb" default="gdb -ex run --args" />

ROS Diagnostics

The bota_driver uses the ROS diagnostics (diagnostics) for providing feedback related to the current connection and data status of the connected devices. To monitor the diagnostics, the user should run in a separate terminal window the following command, after a ROS master has been started (otherwise roscore must run):

rosrun rqt_runtime_monitor rqt_runtime_monitor

Configuration

In order to run your existing setup, you should modify accordingly the launch file that matches your case (serial or ethercat - found in rokubimini_[serial|ethercat]/launch directory). In these launch files, there are two kinds of parameters; parameters for each rokubimini and parameters for the bus.

The parameters for each rokubimini are the following:

• name: The name of the rokubimini devices. Needed to handle multiple devices on the master side,
• configuration_file: The relative path to the configuration file of the sensor
• product_name: The product name of each device.
• ethercat_address (EtherCAT only): The address of the EtherCAT device. EtherCAT addresses are distributed to each slave incrementally. The slave closest to the master has address 1, the second one 2 etc.

The parameters for each bus are the following:

• For the ethercat bus:
  • ethercat_bus: The ethercat bus containing the sensor. Is the ethernet adapter name on which the sensor is connected to, as indicated in the ifconfig command output.
• For the serial bus:
  • port: The serial port to connect to communicate with the serial sensor.
  • baud_rate: The baud rate used for the serial communication.

For configuring the sensor parameters, the following parameters can be set in a rokubimini_sensor.yaml file (and set in the configuration_file parameter of the launch file):

• set_reading_to_nan_on_disconnect: Sets the reading to nan when the sensor disconnects
• imu_acceleration_range: 0 = ±2g, 1 = ±4g, 2 = ±8g, 3 = ±16g
• imu_angular_rate_range: 0 = ±250°/s, 1 = ±500°/s, 2 = ±1000°/s, 3 = ±2000°/s
• imu_acceleration_filter: (cut-off Freq) 1 = 460Hz, 2 = 184Hz, 3 = 92Hz, 4 = 41Hz, 5 = 21Hz, 6 = 10Hz, 7 = 5Hz
• imu_angular_rate_filter: (cut-off Freq) 3 = 184Hz, 4 = 92Hz, 5 = 41Hz, 6 = 21Hz, 7 = 10Hz, 8 = 5Hz
• sinc_filter_size: (cut-off Freq high/low@sampling Freq) 51 = 1674/252Hz@1000Hz, 64 = 1255/189Hz@800Hz, 128 = 628/94.5hz@400Hz, 205 = 393/59.5Hz@250Hz 256 = 314/47.5Hz@200Hz, 512 = 157/23.5@100Hz
• fir_disable: false = low cut-off frequency, true = high cut-off frequency from the above result e.g. for sinc filter_size: 48 and fir_disable: 1 you get cut-off freq 1674Hz@1000Hz sample rate
• chop_enable: should be always false
• fast_enable: (only applies if fir_disable is false) True = will result in low cut-off frequency but would be still able to catch step impulses of high cut-off frequency
• calibration_matrix_active: Use the calibration matrix to compute sensor output
• temperature_compensation_active: Compensate drift due to temperature !not supported yet!
• imu_active: Chooses which IMU type is active: 0 = no imu active, 1 = internal IMU active, 2 = external IMU active (if available), 3 = both IMUs active
• coordinate_system_active: Set a user defined coordinate system
• inertia_compensation_active: Enables compensation due to inertia effect
• orientation_estimation_active: Enables orientation estimation and outputs a quaternion

Subscribed Topics

None

Published Topics

• /<bus_name>/<rokubimini_name>/ft_sensor_readings/reading (rokubimini_msgs/Reading)
• /<bus_name>/<rokubimini_name>/ft_sensor_readings/imu (sensor_msgs/Imu)
• /<bus_name>/<rokubimini_name>/ft_sensor_readings/wrench (geometry_msgs/WrenchStamped)
• /<bus_name>/<rokubimini_name>/ft_sensor_readings/temperature (sensor_msgs/Temperature)
• /diagnostics (diagnostic_msgs/DiagnosticArray)

Services

• For Serial devices:
  • /<bus_name>/<rokubimini_name>/firmware_update (rokubimini_msgs/FirmwareUpdateSerial). Arguments:
    • file_path: The path of the firmware update file.
  • /<bus_name>/<rokubimini_name>/reset_wrench (rokubimini_msgs/ResetWrench). Arguments:
    • desired_wrench: The desired wrench to set.
• For EtherCAT devices:
  • /<bus_name>/<rokubimini_name>/firmware_update (rokubimini_msgs/FirmwareUpdateEthercat). Arguments:
    • file_name: The name of the firmware file.
    • file_path: The path of the firmware update file.
    • password: The password for authorization.
  • /<bus_name>/<rokubimini_name>/reset_wrench (rokubimini_msgs/ResetWrench). Arguments:
    • desired_wrench: The desired wrench to set.

Notes:

• The <bus_name> is the name attribute in the node element, that is set in the launch file.
• The <rokubimini_name> is the configuration parameter ft_sensor_x_name that is set in the launch file.

  Support

For any queries or problems found with the software provided, please contact us at sw-support@botasys.com