This repository contains Schunk WSG50-110 ROS-Driver.

This is a ros-driver for the Schunk WSG50-110 Gripper

Note that there is also an other ROS driver now: http://wiki.ros.org/wsg50

This project is a result of the LIAA project. http://www.project-leanautomation.eu/

LIAA received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 608604.

Project runtime: 02.09.2013 – 31.08.2017.

Special Thanks to Mainauthor Florian Röser Current maintainer Lorenz Halt

this section contains the API of the ROS-Node for the WSG50 Driver.

The ROS node for the WSG50 Gripper makes use of:

• ROS Messages (see http://wiki.ros.org/ROS/Tutorials/CreatingMsgAndSrv)
• ROS Services (see http://wiki.ros.org/ROS/Tutorials/CreatingMsgAndSrv)
• ROS actionlib (see http://wiki.ros.org/actionlib_tutorials/Tutorials)

Actions includes all actions provided by the ros-driver for the schunk wsg50 gripper.

• WSG50HomingAction: Provide an homing action.
• Homing Action: This action has to be run before any other motion command is send.

1. @goal: bool direction
   • positive direction
   • negative movement direction
2. @result: int status_code (see possible Status Codes for detailed description)
3. @feedback
   • float width (in mm)
   • float speed (in mm/s)
   • float force (in newton)

• WSG50PrePositionFingersAction: Pre-Position fingers with given widht and speed.

1. @goal params: bool stopOnBlock: defines if the pre-position movement should stop if something is in the way
   • float width (in mm)
   • float speed (in mm/s)
2. @result: int status_code (see possible Status Codes for detailed description)
3. @feedback
   • float width (in mm)
   • float speed (in mm/s)
   • float force (in newton)

• WSG50GraspPartAction
• WSG50ReleasePartAction

includes the messages and topics sent by the ROS-Driver

Advertized as ROS-topic: /system_state

this message will be published about every 20 milliseconds.

includes the services provided by the ROS-Driver

• setAcceleration.srv: This sets the acceleration for the gripper motions, which are the movements of the fingers.
• setSoftLimits.srv: This service will set the soft limits (minus and plus) for the gripper motions
• clearSoftLimits.srv: Note: Even if the soft limits are cleared, the ros-wrapper will return soft limits in the system-state message, but these soft limits will then be equal to the maximum and minimum width of the finger movements.
• setForceLimit.srv: The force-limit defines with which maximum force the fingers will try to move, or at which force-threshold the fingers will stop moving.
• stop.srv: this will stop any motion
• fastStop.srv: this will stop any motion and put the gripper in a state where it requires the message "Acknowledge Fast Stop" before it can accept any other command!
• ackFastStop.srv: This will release the fast-stop state so the gripper can accept new commands

Please consider the Schunk documentation for the grasping state graph!

When you are programming the Gripper, then you should be aware of these states, e.g. it is not possible to send the "Grasping" command when the gripper is in the state "No Part Found"!

Most Gripper Commands are already implemented into the WSG50Controller.cpp class, but still may need to be implemented as ROS-Services or ROS-Actions.

Getter methods to read the different system states like temperature, force and speed. Most of these values are already published in a single ROS-Message ''systState'' with a defined frequency (by default every 20ms).

These commands include the general system configuration commands.

(Source Weiss Robotics:) ''The WSG series of grippers provides a sensor port n each base jaw to which sensor fingers can be connected to. The following commands are used to access and control these fingers.''

the returned status-codes are int-values. Below is the short description:

• typedef enum TStat
• typedef struct SSTATE