Difference between revisions of "250a Haptics Lab"

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(Part 1: Test setup and run spring)
m (Part 1: Test setup and run spring)
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~>pd 3D-spring.pd&</tt>
 
~>pd 3D-spring.pd&</tt>
  
* Increase the stiffness in the Z axis from zero.
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* Test the spring governed by F<sub>z</sub> = $f2(z<sub>0</sub> - $f1).  F<sub>z</sub> is the force exerted by the motors in the z-axis, $f1 is the position of the Falcon grip in the z-axis, $f2 is the spring stiffness, and z<sub>0</sub> is the rest position of the spring.  In this example, we have z<sub>0</sub> = 0.
Test the spring governed by F<sub>z</sub> = $f2(z<sub>0</sub> - $f1).  F<sub>z</sub> is the force exerted by the motors in the z-axis, $f1 is the position of the Falcon grip in the z-axis, $f2 is the spring stiffness, and z<sub>0</sub> is the rest position of the spring.  In this example, we have z<sub>0</sub> = 0.
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<ol><li>Check the messages in the Pd window to ensure that the Falcon has been initialized properly.</li>
 
<ol><li>Check the messages in the Pd window to ensure that the Falcon has been initialized properly.</li>

Revision as of 09:38, 21 October 2009

The goal of this lab is to introduce three-dimensional active force feedback. Each haptic effect can easily be coupled to a sound because the feedback loop is controlled directly Pd. Different haptic effects suggest different sounds; different sounds suggest different effects. What are the most interesting mappings? Which are appropriate, controllable, even "expressive". Try each sound control with and without haptic feedback enabled. Are there some that simply cannot be played without haptics?

Falcon.jpg


Part 0: Setup

  • Install the new and improved .pdsettings file on your CCRMA linux account according to the directions on this page.


  • Add the following line to your ~/.bashrc file. (If you want to use emacs to do this, type emacs ~/.bashrc)

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/ccrma/courses/250a/pd/externs


  • You may wish to verify that no one has changed the wiring on your machine in the MAXLAB.
    • The Falcon should be connected over USB to the machine by way of a USB hub.
    • A -30V DC power supply should be plugged into the Falcon. The power supply has a yellow band on the end of the plug.


  • If you need to make a 250a directory, type

~> mkdir ~/250a

~> mv ~/Desktop/Falcon-pd-linux.zip ~/250a

  • Unzip the files by typing

~> cd ~/250a unzip Falcon-pd-linux.zip

Part 1: Test setup and run spring

  • Run 3D-spring.pd

~>cd ~/250a/Falcon-pd-linux/spring ~>pd 3D-spring.pd&

  • Test the spring governed by Fz = $f2(z0 - $f1). Fz is the force exerted by the motors in the z-axis, $f1 is the position of the Falcon grip in the z-axis, $f2 is the spring stiffness, and z0 is the rest position of the spring. In this example, we have z0 = 0.
  1. Check the messages in the Pd window to ensure that the Falcon has been initialized properly.
  2. Hold down the center button of the Falcon grip to enable haptics.
  3. Increase the stiffness of the spring from zero by dragging the number box.
  4. Make sure that you understand how the "expr" object works.