dynamixel_gripper's Introduction

Dynamixel Servo Gripper

Purpose

An end effector is the device at the end of a robotic arm, designed to interact with the environment. To provide for a low cost gripper solution for the underlying project, 2 dynamixel motors with claws affixed are attached alongside each other. This library (built & tested with kinetic) provides an easy-to-use ROS package to control the grip.

Getting started

Ensure dynamixel motors have the proper power supply & both servos have a different ID (you can change them by using a GUI tool
Ensure you have download the packages for dynamixel_controllers; you can do it by running the command:

sudo apt-get install ros-kinetic-dynamixel-controllers

Download & place this package in your_catkin_workspace/src; remember to overlay your workspace directory in ROS_PACKAGE_PATH
Run the following commands:

catkin_make
roscd dynamixel_gripper/scripts
chmod +x getLoad.py
chmod +x GripperOpenClose.py

To start using the ROS API:

roslaunch dynamixel_gripper gripper_manager.roslaunch

ROS API

Published Topics

/gripper/load (dynamixel_gripper/load_state)
- Returns the current load in both servos
/gripper/state (dynamixel_gripper/grip_state)
- Returns 0 if gripper is open, and 1 if gripper is closed; contains other motor info as well

Subscribed Topics

/gripper/command (dynamixel_gripper, std_msgs/Int32)
- 0 - open, 1 - close

Important points

Gripper may get hot after prolonged use. Keep track and ensure its temperature does not exceed 65 degrees celsius. To track temperature, check published topic /gripper/state
Certain parameters can be adjusted in 'tilt.yaml' & 'gripper_manager.launch' files, such as port number, servo id search range, baudrate, joint velocity, open & close angles

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