The Setup

A test apparatus and protocol have been developed and human subject experiemnts are underway. In a first set of experiments, two kinds of vibrational haptic displays will be evaluated: The first is a small voice-coil motor attached to a compliant mechanism. It is adapted from the commercial Logitech “Feel-It” mouse, designed by Immersion Corp., San Jose CA. The device produces vibrations over a range between 10-200 Hz and stimulates a large receptive field of approximately 100 cm2. The second device is a small “C2 tactor” from EAI Inc., Winter Park, FL, consisting of a probe attached to a short-stroke linear motor. In comparison to the first display, it produces a more localized stimulus and has a working frequency range of 20-300 Hz. Both stimulators are attached using an adjustable Velcro strap.

A computer running a realtime operating system (Matlab xPC) has been set up to control the stimulators with various waveforms, using a digital/analog output card and linear current amplifiers. Accelerations near the sites of stimulation will be monitored using commercial accelerometers and an analog/digital input card for the computer. In future experiments, the motions of markers on the subjects may be tracked with a high speed vision system.