Ooh yes, dear. Let me explain.
Haptics or haptic technology is the technology of applying touch sensation while interacting with a virtual environment. Incorporating haptic feedback into Virtual/Augmented reality (VR/AR) systems plays a crucial role in enhancing realism, interaction, immersion, and imagination.
Over recent years, the development of haptic devices has exponentially grown, owing to their potential in several applications such as medical simulation training, robotics, teleoperation, education, the video gaming industry, rehabilitation, interactive design, and human-computer interaction.
Our human nervous system is responsible for the two primary types of sensation: kinesthetic and cutaneous. The kinesthetic system employs receptors located in our muscles, tendons, and joints for the sensing of forces and displacements. When holding an object in your hand, kinesthetic feedback tells your brain the approximate size, weight, and orientation of the object relative to your body (i.e., It gives the physical world around us the right dimension). Cutaneous or tactile feedback is responsible for stimulating the receptors located on the skin to feel vibrations, pressure, temperature, and the texture of any object.
The most widely used kinesthetic haptic devices are the n-degrees of freedom electro-mechanical systems, Touch™ and Phantom®Premium from 3D Systems Inc., and Falcon from Novint Technologies. These devices provide a wide range of force (order of Newtons) with high spatial and temporal resolutions. However, electro-mechanical kinesthetic devices suffer from drawbacks such as mechanical friction, backlash, inertia as well as the limited workspace the device stylus provides. In addition, this type doesn’t provide the user with sufficient realism due to the transmission of forces using tethered links.
The cutaneous/tactile approach is currently one of the most used haptic feedback devices. The vibration on our smartphones or game controllers enables the cutaneous perception of the user’s hand when we type or crash a car in a video game. The miniaturization and simple design of vibration motors make them a cost-effective and feasible implementation haptic technique. However, these systems lack realism and expressivity compared to traditional physical means which involve the human sense of touch. Vibration patterns are difficult to distinguish in many situations such as walking and offer limited information (i.e., duration, strength, and vibration pattern).
Mid-air haptics is an emerging technology that can enhance interaction in virtual environments by providing haptic perception in mid-air. This type of device conveys haptic stimuli at a distance without direct contact. Therefore, mid-air devices are more suitable for AR/VR ecosystems. Several research groups have developed mid-air haptic devices based on forces generated at a distance using acoustic radiation pressure (Ultrasound transducers), air pressure, and magnetic field gradient. Up-to-date the most notable effort to commercialize mid-air haptics is Ultraleap (formerly, Ultrahaptics). Stratos system from Ultraleap creates a tactile sensation by using ultrasound transducers that provide acoustic radiation pressure at the user's hand skin. However, ultrasound-based haptic devices generate limited forces range (order of few milli Newtons) compared to kinesthetic haptic devices.
Using magnetic field to provide haptic feedback has obtained considerable research attention in recent years, this technique has proven its ability to provide mid-air haptic feedback with a range of forces/torques similar to that of the kinesthetic devices as well as its ability to provide tactile feedback. To the date of writing this report, there is no mid-air - electromagnetic-based - haptic device available in the market capable of generating forces/torques in a range suitable for both kinesthetic and cutaneous sensation.
The absence of such a device decelerates the development of haptic applications and limits the accessibility of kinesthetic mid-air haptics technology. The availability of an electromagnetic-based haptic device will benefit researchers and developers in the following areas and applications:
• Augmented/Virtual reality.
• Interactive gaming.
• Medical training simulators.
• Human-Robot Interaction.
• Human-computer interaction.
• Internet touch.
• Haptic psychophysics and perception.
• Kinesthetic learning, 3D computing interface for disabled people.
• Haptic rendering techniques and algorithms.
• Haptic Interfaces design & control.
• Other innovative uses of haptic rendering using magnetic fields