EZGripper

A ROS package that serves as a driver to the EZGripper module designed by SAKE Robotics. If you are not using ROS, use https://github.com/SAKErobotics/SAKErobotics

Tutorial

Hardware

Install the python EZGripper library. For kinetic and melodic use this link and for noetic use the ubuntu 20.04 branch.

Install the upatras_gazebo_plugins to enable Gazebo to mimic the EZGripper joints:

git clone https://github.com/roboticsgroup/roboticsgroup_upatras_gazebo_plugins.git

Install all the remaining dependencies using rosdep, at the root of your ROS workspace:
```
rosdep install --from-paths src --ignore-src -r -y
```

Clone the ROS Driver at you src folder:

For ROS kinetic and melodic

git clone --branch=master https://github.com/SAKErobotics/EZGripper.git

For ROS noetic

git clone --branch=noetic-devel https://github.com/SAKErobotics/EZGripper.git

Build your workspace and source it:
```
catkin_make && source devel/setup.bash
```
Connect your USB joystick to the system, and execute:
```
roslaunch ezgripper_driver joy.launch
```

Software

Set the bash variable according to your gripper module - (dual_gen1, dual_gen2, dual_gen2_single_mount, dual_gen2_triple_mount, quad):
```
export ezgripper_module=<your_gripper_module>
```

Launch the gripper module in RViz :

roslaunch ezgripper_description display.launch ezgripper_module:=${ezgripper_module}

Similarly to launch in Gazebo:

roslaunch ezgripper_gazebo gazebo.launch ezgripper_module:=${ezgripper_module}

To actuate the gripper into its respective open/close configurations in Gazebo:

# Open Gripper
rosrun ezgripper_control open_gripper

# Close Gripper
rosrun ezgripper_control close_gripper

Result of actuation:

MoveIt!

To launch the ezgripper in RViz only:

roslaunch ezgripper_${ezgripper_module}_moveit_config demo.launch

To launch the ezgripper in Gazebo and RViz for control:

roslaunch ezgripper_${ezgripper_module}_moveit_config demo_gazebo.launch

To control the ezgripper hardware through MoveIt!:

roslaunch ezgripper_${ezgripper_module}_moveit_config ezgripper_${ezgripper_module}_moveit_planning_execution.launch

Additional Configurations

Setup parameters in joy.yaml file
- port -
  serial device (like /dev/ttyUSB0) or tcp endpoint (like 192.168.0.200:5000) to use.
- baudrate -
  baud rate of the serial device, not used for tcp.
- no_of_grippers -
  number of grippers to control.
- Depending upon the number of grippers, gripper profiles can be created as shown:
```
gripper_1:
	action_name: gripper_cmd
	servo_ids: [1]
	module_type: dual_gen2_single_mount
	robot_ns: main
```
  action_name -
          name of the action to be used.
  servo_ids -
          list of servo ids to control. (several ids if several grippers are to be used as one group). For example [9] and [10,11] for two grippers.
  By default, SAKE Robotics delivers its grippers with address 1 for Duals and 1 and 2 for Quads and 57kbps.
  module_type -
          type of the gripper module. (dual_gen1, dual_gen2, dual_gen2_single_mount, dual_gen2_triple_mount, quad).
  robot_ns -
          namespace of the robot.

Example launch files to support various EZGripper configurations.

roslaunch ezgripper_driver joy.launch
# joy.launch is configured for a single servo gripper (dual) and the USB interface

roslaunch ezgripper_driver joy2.launch
# joy2.launch is configured for two independent servos (quad independent) and the USB interface

roslaunch ezgripper_driver joy2sync.launch
# joy2sync.launch controls two servos as if it were a single servo (quad dependent) and the USB interface

roslaunch ezgripper_driver joy_tcp.launch
# joy_tcp.launch controls a single servo via TCP instead of USB

Action API

The driver provides an implementation of the SimpleActionServer, that takes in control_msgs/GripperCommand actions.
A sample client (scripts/ezgripper_joy_action_client.py) is included that provides joystick control using the action API.

URDF Models

Access the URDF models for additional information.

TroubleShooting

Serial connection issues:

The following message indicates you have a new version of serial library that causes issues.
```
Error message: 'Serial' object has no attribute 'setParity'  ---
```
Do the following command to load an older serial library.
```
sudo apt-get install python-serial==2.0.0
```
This indicates the user does not have privileges to use the /dev/ttyUSBx:
```
Error message: permission denied (get accurate error message).
```
The solution is to add the <user> to the dialout group. After executing the following command, reboot.
```
sudo adduser <user> dialout
reboot
```

ROS Controller Issues:

Check whether the joint_state_controller and the ezgripper_controller modules are loaded:
```
rosservice call /ezgripper_${ezgripper_module}/controller_manager/list_controllers
```

ROS Diagnostics

View the diagnostics of the ezgripper_module:

rosrun rqt_runtime_monitor rqt_runtime_monitor

leander-dsouza/EZGripper