Recent advances in scientific research may make robotic prosthetics and virtual reality simulations more effective than ever before. Researchers in Hong Kong have developed a new glove-like technology that not only allows users to experience the sensations of their hands when interacting with virtual objects, but also tailors the intensity of the sensations to a person’s neural sensitivity.
Haptic technology is defined as technology that relies on computer-generated forces, vibrations, or motion to provide people with an artificial sense of touch. Along with virtual reality, this technology has become even more important in medicine over the past decade. Not only are surgeons relying on virtual reality to perform operations, but haptic technology could dramatically improve the lives of amputees with robotic prosthetics. In recent years, researchers have found that robotic prosthetics, which can provide patients with an artificial sense of touch, can significantly reduce the mental effort required to operate the prosthetic. The artificial sense of touch could also improve a patient’s overall ability to control a prosthetic.
While scientists have developed haptic technology for clinical applications in the past, previous attempts have tended to be bulky, inconvenient, and not customizable for each user.
Now, researchers have developed a new iteration of haptic technology that involves an ultra-thin, glove-like technology called WeTac. WeTac incorporates multiple electrodes throughout the glove structure and provides users with electrical feedback to create a tactile sensation in their hands. Not only does the technology have the potential to improve robotic surgery outcomes, but it is a major development in haptic technology that could also be applied to people with disabilities and those using robotic prosthetics.
The first challenge in creating WeTac was to come up with a design that simulates the dynamic and changeable sensations people experience when using their hands.
Consider the experience of shaking someone’s hand. You may only feel the handshake in certain areas of your palm or fingers. These contact areas may change when you shake hands. The pressure of your or their grip may also change. In addition to this, certain areas of our hands are inherently more sensitive to touch than others. The sensations we experience in our hands are very dynamic, even for something as basic as shaking hands.
The target of Yao et al. is to design a haptic glove that captures these dynamic sensations when users interact with virtual objects. To this end, WeTac designed 32 electrodes on the surface of the palm and fingers. This will allow the researchers to adjust the strength of the electrical signal at 32 different points in the hand and allow them to generate a more accurate sense of touch throughout the hand.
Using electrodes to create artificial sensations also enabled Yao et al. Create WeTac in an incredibly lightweight form. Electrodes have previously been used in thin wearable devices that can be placed directly on the skin without causing any irritation. This makes them an excellent choice for making devices that are lightweight and convenient.
By using electrodes, Yao et al. Current can be induced throughout the hand. The idea is that these electrical currents activate nerves in a person’s hand, effectively inducing the sense of touch that a person might feel when interacting with a physical object. Yao et al. The WeTac is designed so that it can generate electricity through a blue control unit attached to the user’s wrist. This control unit will be wireless capable and can be controlled from a phone or computer. This will allow WeTac users to move freely.
To test the device, Yao et al. took the first step. The electrical stimulation settings of the WeTac were optimized for each participant. The sensitivity of people’s hands can vary from population to population. For example, men are generally less sensitive to touch than women. Sensitivity also decreased in older adults compared to younger adults. To customize the device, Yao et al. The average electrical stimulation threshold was measured for each participant and each of the 32 electrodes in their hands.
As expected, women had lower electrical stimulation thresholds than men, on average. Younger individuals also showed lower thresholds. The exception to this pattern was that women who had more calluses on their hands due to work had a higher threshold. In other words, Yao et al. It was found that in addition to gender and age, hand sensitivity also varies depending on a person’s job or daily activities.
After calibrating WeTac according to each volunteer’s sensitivity level, Yao et al. Get ready to test WeTac in a virtual reality simulation. The first simulation involved participants slowly grasping a virtual tennis ball and a virtual cactus. This simulation will allow the researchers to determine that WeTac can produce different sensations based on the texture of a stationary virtual object. After running the simulations, the team found that tennis balls elicited a mild tactile sensation, while cacti caused mild pain or an uncomfortable tingling sensation.
The researchers also tested a simulation in which a virtual mouse and a piece of cheese appeared in the participant’s hand. Participants then reported how they felt when the virtual mouse was moved over their hand to eat each piece of cheese. This allowed the researchers to determine that WeTac was also effective in inducing the sense of touch in moving dynamic objects.
Overall, this research demonstrates a significant advance in haptic technology. As WeTac and other lightweight haptic feedback devices continue to be developed, we may start to see more sophisticated virtual reality and robotic prosthetics that utilize haptic feedback and could improve the outcomes of remote/robotic surgery and the lives of amputees.