Kinematic Trajectory and Force Capture System

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Revision as of 21:22, 13 July 2010 by Advaitjain (Talk | contribs) (Hardware)

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Advait Jain (

What this does

This page describes the capture system that we designed to log the kinematic trajectory through which mechanisms (doors and drawers) move and the forces used to operate them.

We first used this setup in this paper: The Complex Structure of Simple Devices: A Survey of Trajectories and Forces that Open Doors and Drawers. Advait Jain, Hai Nguyen, Mrinal Rath, Jason Okerman, and Charles C. Kemp. IEEE RAS/EMBS International Conference on Biomedical Robotics and Biomechatronics (BIOROB), 2010. This paper and others can be downloaded from the Heathcare Robotics Lab website (

Picture of the Setup

Capture setup.jpg Handheld hook.jpg


This is the hardware setup that we use:

  • Camera: Point Grey DragonFly2 with remote head
  • Lens: Varifocal Video Lens 4mm - 12mm (Stock Number: NT58-365) ($150.00) link
  • Tripod for the camera.
  • Studio Lights
  • Laptop: Anything that runs Ubuntu and has a firewire port. Four pin firewire port will require a hub and external power to provide power to the DragonFly.
  • Mount for the DragonFly: See Image and the CAD Models.
  • Handheld Hook: See images and the CAD Models. I cut all the parts (except the hook) from 4.5mm thick acrylic sheets on a laser cutter. I 3D printed hook_handheld.sldprt.
    • The rubber ball for the operator to grab onto (mounts to hook_checkerboard_1.sldprt) was something that I scavenged from the lab. I don't have an easy way to show its design.
    • The difference between hook_adaptor_nano.sldprt and hook_extender_nano.sldprt is the radius of the holes. The adaptor allows you to tap the holes for an M3 screw and the extender holes let M3 screws pass through.
  • Checkerboard patterns: Checked into the subversion repository with all the code.
  • Force Torque Sensor: ATI Nano 25 with a calibration of SI-125-3 and the Controller F/T System (link)