The SWD® StarterKit comes with a simple ROS configuration, which is launched automatically at startup. A brief technical description is available here, under "Main Specifications", and "Downalod".
All you need is to:
- Turn on SWD® StarterKit
- Use the joystick to control the robot.
- Connect to the WiFi hotspot (named
SWD®-Starter-Kit-XXXXXX) - Open URL http://10.10.0.1 to access the web interface.
The default ROS configuration uses the hector_mapping package to build a map of the environment. An alternative mapping process based on iris_lama is also available.
It also comes with a web interface, to visualize the map and pose of the kit, and the safety functions.
The SWD® StarterKit comes with a preinstalled Linux, and the Robot Operation System (ROS) Middleware. It is configured as a plug-and-play mobile platform. ROS nodes are started automatically at launch time, thanks to Linux services.
The SWD® StarterKit requires services to manage the D-Bus session and abstract the CANOpen communication. Services are managed using Systemd, and uses D-Bus to communicates with each other.
This service launches a D-Bus user session, and stores the information in /tmp/SYSTEMCTL_dbus.id file. Other services can load this file and get the session parameters. So that, they can communicate with each other over D-Bus.
This service runs with root permissions. So, it can mount and setup the CAN bus interface (can0). It is also used as a synchronization point for the services depending on it.
These services launches ez-Wheel SWD® Service for the left and right SWD® motors.
It is the entry point for the ROS world. This service starts starter_kit.launch from the package swd_starter_kit_bringup. Note that, starter_kit.launch also launches swd_ros_controllers that requires an access to the D-Bus session created by ezw-dbus-user-session service. If it is launched from Systemd, the service automatically sets-up the relevant D-Bus session
parameters from /tmp/SYSTEMCTL_dbus.id file.
The SWD StarterKit comes with a default ROS configuration, the ROS graph of nodes running by default is illustrated in the following figure.
The package swd_starter_kit_bringup is the entry point for the SWD® StarterKit. At startup, swd_starter_kit_bringup/starter_kit.launch is started, and provides an example of configuration for the SWD® StarterKit.
This launchfile starts the following ROS nodes:
swd_ros_controllers/swd_diff_drive_controller: The differential drive controller for the two SWD® wheels. It takes a target velocity as input and provides the odometry, the associated TFs, and the safety functions status as output.swd_robot_manager/robot_manager.py: The robot manager is used to centralize the management of the kit in a single node.joy/joy_node: The joystick driver.teleop_twist_joy/teleop_node: The joystick to twist conversion node. It reads the inputs from the joystick message and convert them as a Twist message (linear and angular velocities).urg_node/urg_node: The IDEC SE2L LiDAR driver.rosbridge_server/rosbridge_websocket: Patched version of the websocket bridge, used to redirect ROS messages to the web interface.tf2_web_republisher/tf2_web_republisher: Republish TFs to the web interface.tf/static_transform_publisher: Publishes the static transforms of the robot.hector_mapping/hector_mapping: The HectorSLAM mapping. It uses odometry and LiDAR information to map the environment.
The SWD® StarterKit requires swd_ros_controllers package to control both SWD motors. This package includes an implementation of a differential drive for two SWD® motors. Further informations are available on github.com/ezWheelSAS/swd_ros_controllers.
The SWD® StarterKit cames with preconfigured pair of SWD® motors. However, you can change the configuration using commissioning scripts available on swd-starter-kit-config repository.
The LiDAR cames preconfigured with two security zones, one for the Safety Limited Speed (SLS), and the other for the forward Safe Direction Indication (SDI+). The configuration file is included also on the swd-starter-kit-config repository. If you need to change zones, make sure the LiDAR OSSDs are correctly configured (see swd-starter-kit-config for more information).