Hook End Effector

Author

Advait Jain (http://www.cc.gatech.edu/~advait)

What this does

We first used this hook as an end effector in this paper: Pulling Open Novel Doors and Drawers with Equilibrium Point Control. Advait Jain and Charles C. Kemp. IEEE-RAS International Conference on Humanoid Robots (Humanoids), 2009. This paper and others can be downloaded from the Heathcare Robotics Lab website (http://www.healthcare-robotics.com)

The hook was inspired by how humans sometimes use a finger or fingers to hook around a handle and pull something open. We also took inspiration from prosthetic hooks, which have been successfully used with remarkable versatility and effectiveness.

• The Hook as an End Effector
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Pictures of the Setup

• Servo Tilting the UTM
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  Firefly Camera, UTM and Servo (left to right)

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• Alternate Configuration
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Hardware

Image of the solidworks part for the bracket to mount the UTM on to the servo.

This is the hardware setup that we use:

• Tilting servo: Robotis Servo (typically we use RX-28) http://www.crustcrawler.com/motors/RX28/index.php?prod=66
• This gives a serial interface to control the servo: http://www.crustcrawler.com/electronics/USB2Dynamixel/index.php?prod=65
• Hokuyo UTM. (http://www.acroname.com/robotics/parts/R314-HOKUYO-LASER4.html)
• Bracket to mount the Hokuyo on to the servo.
  • This is a custom part that we have designed.
  • The solidworks CAD file (utm-servo-bracket.sldprt). This requires Solidworks 2009.
  • We have taken two routes for making the bracket
    1. buy Aluminium channels from http://mcmastercarr.com and drill the appropriate holes.
    2. use http://www.mfg.com to get the part manufactured from the CAD file. Will take between a week to 10 days.

Code

• ROS (http://www.ros.org)
• You will need the following ROS packages from our public ROS repository (available at http://code.google.com/p/gt-ros-pkg/wiki/hrl_content_summary)
  1. robotis
  2. hrl_hokuyo (requires hokuyo_node - http://www.ros.org/wiki/hokuyo_node)
  3. hrl_tilting_hokuyo