Kentaro Yasu's MagneLayer Offers "Force Field Fabrication" for Haptics with No External Power

Kentaro Yasu, a researcher at NTT Communication Science Laboratories, has published a paper detailing a means of creating magnetic patterns for haptic interaction — dubbed "force-field fabrication" — using low-cost layered magnetic sheets: MagneLayer.

"Magnets are very useful for the rapid prototyping of haptic interactions. However, it is difficult to arrange fine and complex magnetic fields rapidly," Yasu explains of the problem."Therefore, we invented a method for fabricating complex geometric magnetic patterns by overlaying multiple magnetic rubber sheets. This method resolves the trade-off between magnetized pattern complexity and the time required for magnetization.

"By layering multiple magnetic sheets that have simple magnetic patterns, various types of geometric magnetic patterns, such as checkered and diamond ones, can be generated on the top surface. By applying superposed magnetic fields, various types of tactile stimuli and haptic interaction can be created rapidly. Furthermore, the superposed magnetic fields can be changed dynamically by rotating the layered magnetic sheets."

The MagneLayer material itself is made from magnetic rubber sheets magnetized in a stripe pattern, a process which takes about 30 seconds per A4-size sheet by hand, which are then overlaid on top of one another. Once overlaid, the stripe pattern becomes a chequerboard — something which would take a magnetizing plotter around seven times longer to achieve on the same material.

"However," Yasu notes, "the magnetic plotter method and our method can complement each other. The plotter machine is slow but can provide precise magnetic patterns. Therefore, a precise magnetic lattice pattern will be provided by stacking the sheets magnetized by the plotter machine. We think that the combination of our method and the magnetic plotter method can provide a synergistic effect by taking advantage of each method's characteristics."

To demonstrate the capabilities of the MagneLayer material, Yasu and his team put together a series of demonstration applications — beginning with channel control of a simple HEXBUG Nano bristle-bot robot. Another larger-scale example was the creation of a smart-snap whiteboard, allowing a magnetic ruler to snap to an otherwise-invisible grid. A final, and more complex, variant resulted in a device that could rotate the layers of the grid to create a "haptic shifter" — changing the resulting haptic feedback without the need for a power supply, and with potential as an interface for virtual reality systems.

Yasu's paper, published as part of the Proceedings of the 2020 CHI Conference on Human Factors in Computing Systems (CHI'20), is available under open access terms on the ACM Digital Library.