This repository contains the ROS 2 driver, controller, and description packages for working with a Robotiq EPick Gripper.
The epick_driver package serves as a ROS 2 Hardware Interface for the Robotiq EPick Gripper, enabling direct interaction with the gripper hardware.
Below is a sample configuration that outlines various parameters for this interface.
<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
<xacro:macro name="epick_driver_ros2_control" params="name">
<ros2_control name="${name}" type="system">
<hardware>
<plugin>epick_driver/EpickGripperHardwareInterface</plugin>
<!-- Serial connection parameters -->
<param name="usb_port">/dev/ttyUSB0</param>
<param name="baud_rate">115200</param>
<param name="timeout">0.2</param>
<!-- Gripper parameters -->
<!-- Set use_dummy to true to connect to a dummy driver for testing purposes. -->
<param name="use_dummy">false</param>
<!-- The address of the gripper. -->
<param name="slave_address">0x9</param>
<!-- The gripper operation mode: AutomaticMode or AdvancedMode. -->
<param name="mode">AdvancedMode</param>
<!-- The following parameters are only required for the AdvancedMode. -->
<param name="grip_max_vacuum_pressure">-60</param>
<param name="grip_min_vacuum_pressure">-10</param>
<param name="grip_timeout">25.0</param>
<param name="release_timeout">2.0</param>
</hardware>
<gpio name="gripper">
<!--
Command interface to control the gripper:
1.0 = grip
0.0 = release
-->
<command_interface name="grip_cmd"/>
<!--
State interface that follow the value of the command interface:
1.0 = successful grip
0.0 = successful release
-->
<state_interface name="grip_cmd"/>
<!--
Return the object detection status:
0.0 = unknown
1.0 = object detected at minimum pressure
2.0 = object detected at maximum pressure
3.0 = no object detected
-->
<state_interface name="object_detection_status"/>
</gpio>
<!--
This is optional configuration if you want to publish the state of the
gripper as a joint state interface.
-->
<joint name="gripper">
<!--
State interface that follows the value of the gripper/grip_cmd
command interface:
1.0 = successful grip
0.0 = successful release
-->
<state_interface name="position"/>
</joint>
</ros2_control>
</xacro:macro>
</robot>
The hardware interface exposes a command interface labeled grip_cmd for gripping and releasing operations. Assigning the value of 1.0 to this command interface initiates the gripping action, while a value of 0.0 triggers the release mechanism.
A parallel state interface named grip_cmd reflects the status of the performed command.
The interface also offers an object_detection_status state interface to provide real-time object detection feedback during the grip operation.
The epick_controllers package establishes a ROS 2 Controller that communicates with the hardware interface through ROS 2 messages.
The controller exposes a ROS 2 service /grip_cmd that accepts a boolean request to control the gripper. A true request initiates gripping, whereas a false request triggers release.
For monitoring purposes, the controller also provides a /object_detection_status topic that returns one of the following object detection states:
- UNKNOWN;
- OBJECT_DETECTED_AT_MIN_PRESSURE;
- OBJECT_DETECTED_AT_MAX_PRESSURE;
- NO_OBJECT_DETECTED.
No specialized configuration is needed for the controller. Here is a sample controllers.yaml file for reference:
controller_manager:
ros__parameters:
update_rate: 30 # Hz
epick_controller:
type: epick_controllers/EpickController
The epick_hardware_tests package includes a set of terminal-based commands designed for hardware validation. The available commands are as follows:
activate: Establishes a connection to the gripper and activates it.deactivate: Connects to the gripper and deactivates it.get_status: Obtains the current status of the gripper after activation.grip: Initiates the gripping action.release: Executes the release operation.