Using Pot-Magnets to Enable Stable and Scalable Electromagnetic Tactile Displays

Area of Science:

• Engineering
• Human-Computer Interaction
• Materials Science

Background:

• Developing high-density haptic displays requires overcoming challenges in actuator force and inter-actuator interference.
• Electromagnetic (EM) actuators offer potential for precise tactile feedback but often suffer from magnetic crosstalk in dense arrays.

Purpose of the Study:

• To design, fabricate, and test a scalable haptic display utilizing EM actuators with minimized inter-taxel interaction.
• To evaluate the psychophysical perception of tactile stimuli generated by the novel haptic display.

Main Methods:

• A 4x4 array of taxels was developed, each featuring a pot-magnet actuator system with planar microcoils.
• A magnetic shielding architecture was implemented to reduce magnetic coupling between adjacent taxels.
• Psychophysical experiments were conducted to assess human perception accuracy under different actuation modes.

Main Results:

• The magnetic shielding reduced neighboring magnet interaction by over an order of magnitude, with only a 10% reduction in coil/magnet interaction.
• The display achieved displacements of 0.55 mm and forces of 40 mN per taxel at 1.7 W power consumption.
• Human perception accuracy reached 91% in the pulling configuration and 100% in the pushing configuration.

Conclusions:

• The developed magnetic shielding architecture effectively mitigates crosstalk in dense EM haptic arrays.
• The haptic display demonstrates high force output and precise control, enabling accurate tactile perception.
• This scalable design offers a promising platform for advanced tactile feedback systems.