An Actuator with a Nice Touch

If you are thinking about getting into the design of virtual reality (VR) systems, you would do well to stick with the graphics, software, or audio subsystems. While these areas are fraught with technical challenges, it is nothing compared to the difficulties faced by engineers that are attempting to simulate the sense of touch. In order to create a convincing experience, these devices must take into account the complexity of the varied receptors found in the skin, and stimulate each in a way that reproduces a real-world sensation.

That is much easier said than done, which is why haptic feedback so often takes the form of a simple vibration motor. This technique is very limited in the sensations it can produce, so unfortunately, the tactile feedback is not very immersive. This shatters the illusion of reality in today’s VR experiences. To convincingly reproduce real-world tactile experiences, significant technological advancements will be needed.

A team of engineers at Northwestern University has just put forth a solution that has the potential to move the field forward. They have developed a compact, lightweight, and wireless actuator that is capable of moving in any direction. This enables it to produce a wide range of sensations, including vibrations, stretching, pressure, sliding, and twisting. With such a varied repertoire, this system could make future VR experiences far more immersive.

The actuator consists of a tiny magnet nested within three copper coils. By running electrical current through the coils, a magnetic field is generated, which then moves the magnet in different directions. This movement translates into a range of tactile sensations on the skin. Unlike conventional actuators that only push or poke, this new design allows for complex feedback such as twisting, pinching, and stretching — greatly expanding the realism of haptic interactions.

While the most obvious use of this haptic technology is in VR, its potential applications extend far beyond gaming and entertainment. The researchers believe their device could be important in areas such as online shopping, remote healthcare, and accessibility for individuals with disabilities.

For instance, the ability to feel fabric textures through a touchscreen could enhance online shopping experiences. Or a doctor conducting a telehealth appointment could gain a better sense of a patient’s condition through touch-based feedback. Furthermore, individuals with visual or hearing impairments could benefit from an added sensory layer in digital interactions.

In the medical field, the technology is also being explored to help patients with neuropathy regain a sense of touch. The team is currently testing a system that places pressure sensors in shoes, translating footstep data into haptic feedback on the thighs (where they still have sensation). This could help individuals with nerve damage walk with greater confidence and stability.

Although there are still challenges to address — such as miniaturizing the actuators further and improving power efficiency — the potential impact is vast. As the team continues refining this technology, the dream of fully immersive digital experiences, complete with a rich sense of touch, appears to be closer to reality than ever before.