The JumpMod haptic backpack makes virtual leaps more realistic

VR technology has come a long way from the early Virtuality systems that inhabited our local malls in the ‘80s and ‘90s, with modern headsets offering 4K resolution, Dolby Atmos surround sound, and motion-sensing controllers. But even the most convincing optical and auditory illusions can’t fully fool our inner ears.

“If you want to feel these big sensations, you’ve got to have the infrastructure first,” University of Chicago PhD student, Romain Nith, told Engadget. “You’ve got to go to theme parks, ride roller coasters, or you need bungie cords pulling you from the ceiling.” And while the sensations are really like what they’re simulating (because you're really being thrown around), “you can't have that in your living room.”

The JumpMod Haptic Backpack prototype, on the other hand, can effectively fool its user’s sense of proprioception to make jumping in VR feel much more lifelike with a device the size of, well, a backpack. It has been developed by Nith and his research team from the University of Chicago’s Human-Computer Integration Lab, which is headed by Pedro Lopes, Associate Professor, Department of Computer Science. The HCI Lab’s research focuses on using technology to “borrow parts of the body for input and output, rather than adding more technology to the body” and, as such, has generated a veritable menagerie of novel devices exploring that concept.

“I think the next generation of devices is not going to be defined by how small they are, or how implanted they are in the body… but more about how deeply they integrate with your body,” Lopes told Engadget. He points to the functional issues of dealing with Google Maps in 2007 — specifically the need to physically print them out for them to be useful. “Now when that runs on your smartphone, the device that can move with you, in your pocket, you can access information anywhere, anytime,” he said. “All of a sudden that makes a lot of sense. So every jump of these paradigms allows you to do something new.”

“We're looking at the body and trying to create technology that really hybridizes with you,” Lopes continued, using smartwatches as an example, which rely on small spinning motors to create the notification vibration. “That is one of the reasons smart watches are so big.”

Instead, a small electrical charge can elicit the same tingling sensation without the need for a “big rotating mass type of device,” Lopes explained. “The sensations, the functionality, ends up being the same and the device looks very different.”

JumpMod takes a similar approach, rapidly shifting the position of a weight worn by the user to fool their senses rather than hoist the user wholesale to practically recreate the sensation. The untethered device is designed to modify the user’s sense of jumping, when used with a VR program, by rapidly lifting and lowering a 2-kilogram weight (which doubles as the device’s power cell) in time with their physical movement. Adjusting the speed of weight’s motion impacted the user’s perceived jump momentum, enabling the team to create sensations of higher and broader jumps, softer and harder landings and being pulled up or down.

The device itself is completely untethered and can operate both indoors and out. In the demo above, the researcher team used the backpack to improve its user’s timing when jumping rope and even took JumpMod to a basketball court to show how it could be used to help (or hinder) players in a game of one-on-one. The current iteration is built to generate as much force as comfortably possible, in order to maximize the generated sensation, so it does tend to be rather loud and heavy.

“We probably don't have to drive it as fast, which generates less noise, and probably don't even need all the weight that we have, which would make for a slimmer backpack,” Lopes said. “Where does that sensation start to occur? Is that at 100 grams, is it at 300 grams? We optimized it for maximum power, rather than for a minimal device. That's the kind of stuff one would do if one were to commercialize [the technology].”

Technically, the device doesn’t even need to be worn, it could theoretically be implanted into the backs of theater seats. “I think that the tension here in VR is really interesting,” Lopes said. “ If you go to the Disney theme park, they play these super-immersive VR scenes, you're on a motion platform and when the scene jumps, the motion platform goes up.” Lope argues that a similar sensation could potentially be produced at a fraction of the infrastructure requirements using JumpMod.

“There's lots of proto-motion platforms for VR, some with special shoes, some move around, some rotate but none of them have really paid off,” Lopes said. “It's a really difficult challenge where, if you want to create an involuntary force and involuntary movement, you need a big infrastructure. We are interested in whether that's possible, but honestly, we don't even know if it is.“

The “involuntary” aspect of these devices and technologies is an ethical sticking point for the field, and one which Lopes’ lab has studied frequently. His students have developed passive systems that allow one user to dictate the hand motions of another, or use electrical muscle stimulation to improve the users’ dexterity — artificially boosting their reaction speeds and shaping their finger positions on a guitar fretboard. They can even be controlled through an exoskeleton to properly form the words of American Sign Language. However, all of those devices require the user to relinquish some degree of control over their bodies to let the machines do their things.

“We call it ‘optimizing agency,’” Lopes said. For most of the projects in his lab, “agency is not super critical.” Stakes are low when allowing a robot to guide your finger positionings when learning to play guitar or have one physically guide your head using electrical muscle stimulation during a workplace safety training experience. “We apply the [EMS pads] to the neck muscles,” Lopes reassured Engadget, which gently buzz the user to make them look around their office space, “so they know where the fire extinguisher is, where the fire exit is.”

Lopes does concede that physically instigating a user to turn their head by externally stimulating their nervous system could be construed as “making people completely lose their sense of agency,” however he notes that his lab consistently includes user overrides for all EMS-related devices. “In all these, we design some form [of override] to keep you in control. For example, in the case of [the head actuation study], if you push against the device, it senses that you're pushing against the direction that it’s starting to move your head and turns off.”

“I think there's more research to be done there, more complex ways to tackle this,” he continued. “Brain Computer Interfaces (BCIs) are really interesting because you can kind of detect what people are thinking, what their goal is, and then you don't even have to activate the system if it's not needed.”