Although companies have previously built tools to bring the sensation of touch to VR, the devices have struggled to realistically reproduce the feel of objects and have used too much energy, said researchers at Carnegie Mellon University (CMU) in Pennsylvania.
Now, thanks to some engineering innovation, the team has built a device capable of simulating the feel of obstacles and heavy objects. The 'Wireality' system uses multiple strings attached to the hand and fingers – by locking the strings when the user's hand is near a virtual wall, for instance, the device simulates the sense of touching the wall.
Similarly, the string mechanism lets people feel the contours of a virtual sculpture, sense resistance when they push on a piece of furniture or even give a high five to a virtual character.
The shoulder-mounted device uses spring-loaded strings to reportedly reduce weight, consume less battery power and keep costs low.
“Elements such as walls, furniture and virtual characters are key to building immersive virtual worlds, and yet contemporary VR systems do little more than vibrate hand controllers,” said research co-author Chris Harrison, assistant professor at the CMU Human-Computer Interaction Institute. User evaluation of the multistring device reportedly found it was more realistic than other haptic techniques.
“I think the experience creates surprises, such as when you interact with a railing and can wrap your fingers around it,” said co-author Cathy Fang, who studied mechanical engineering and human-computer interaction. “It's also fun to explore the feel of irregular objects, such as a statue.”
Other researchers have used strings to create haptic feedback in virtual worlds, but they typically use motors to control the strings. The CMU team wanted to build a device without motors to keep costs down, reduce energy use and ensure it can be easily worn by users.
Instead of motors, the team used spring-loaded retractors, similar to those used with key chains or ID badges. They added a ratchet mechanism that can be rapidly locked with an electrically controlled latch. The springs keep the strings taut and only a small amount of electrical power is needed to engage the latch, so the system is energy efficient and can be operated on battery power.
The researchers attached a string to each fingertip, one to the palm and one to the wrist for the best experience. A Leap Motion sensor, which tracks hand and finger motions, is attached to the VR headset. When it senses that a user's hand is in proximity to a virtual wall or other obstacle, the ratchets are engaged in a sequence to mimic the virtual object. The latches disengage when the person withdraws their hand.
The entire device weighs less than 0.3kg and the researchers estimate that a mass-produced version would cost less than £40.
Fang said the system would be suitable for VR games and experiences that involve interacting with physical obstacles and objects, such a maze. It might also be used for visits to virtual museums. And, in a time when physically visiting shops is not always possible, “you might also use it to shop in a furniture store,” she added.
The device could also likely be applied in engineering, such as in training programs or virtual design, giving an extra tangible dimension to the already-advanced 3D design capabilities in some programs.
The team's research paper was named a best paper by the Conference on Human Factors in Computing Systems, which was scheduled for this month but cancelled due to Covid-19. The paper has been published in the conference proceedings in the Association for Computing Machinery's Digital Library.
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