Haptics: What Are They?
Virtual reality systems and real-worth technologies use haptics to enhance interactions with humans using vibration, touch, and force feedback.
The goal of haptics is to make people feel like the experiences depicted in a virtual reality system are ‘real’. One example of haptic technology used during gaming is mobile phone vibrations.
To interact with computers, haptics use force and tactile feedback. The first simulates certain physical features of the virtualized object, such as pressure and weight. The latter represents the texture of the object (such as its smoothness or roughness).
We need to understand the role of the human skin before we can understand what haptics really do. This complex organ is full of touch receptors and nerve endings called the somatosensory system. A person’s brain is informed of heat, cold, pain, and other sensations by this system.
In less than a second, touch receptors transmit signals to the closest neuron, which then signals the next closest neuron until the brain receives the signal. The brain then determines the response to the sensation.
Similarly, haptics stimulates our somatosensory system to pass on information and provide context to the senses of sound and sight. For instance, a user experiences a ‘pull’ sensation when their finger presses down an application icon in the app tray on an Apple iPhone. The haptic motors of the iPhone generate this sensation to communicate that the app is ready to move, delete, or categorize.
Different methods are used to create vibrations, forces, and other movements in haptic systems. The most common method is the eccentric rotating mass (ERM) actuator. An ERM spinning rapidly causes an instability in the weight force, resulting in motor movement and, subsequently, haptic feedback.
Another method of creating haptic feedback is with linear resonant actuators (LRA). A magnet and spring are bound by a coil and secured with an outer layer in this method. The magnetic mass is vibrated by electromagnetic energizing the coil, resulting in a feedback sensation.
As well as LRA and ERM, other emerging technologies are also being used to provide haptic feedback in a more accessible and realistic manner. Experts use haptics for teaching, training, entertainment, and remote hands-on operations.
Haptic technologies types
Several types of haptic technology exist based on their usage, feedback, and modality. Let’s examine the types of haptic technologies.
The ability to grasp
In haptic technology, gripable devices (like joysticks) provide kinesthetic feedback as a standard. In addition to increasing immersion in games, these devices can also be used to control robots more effectively in remote or virtual environments because of their tactical vibrations, movements, and resistance.
Among the examples of this technology in action is bomb disposal and space exploration. In the latter case, astronauts or on-ground personnel can use haptics-controlled robots to repair equipment (such as spacecraft parts or satellites) without leaving the vessel or even Earth.
The ability to touch
There are a number of consumer applications that use touchable haptic technology; for example, smartphones that respond to taps, rotations, and other movements. Touchable haptics technology will soon be able to replicate object movements and textures (known as haptography) with advancements.
Using programmable textures, companies could allow customers to feel clothing materials like cotton and silk before buying, all from the comfort of their own homes.
A wearable haptic device simulates contact by leveraging tactile stimuli, such as pressure, vibration, and temperature.
The use of virtual reality (VR) gloves to mimic real-world sensations and transmit and receive input from users controlling their virtual avatars or remote robots is a fast-emerging application of wearable haptics.
Feedback as a force
Human skin, muscles, and ligaments are stimulated with this type of haptics, unlike other haptics that generally affect only the top layers of skin receptors.
Human body parts are emulated by two types of haptics: biomimetic and non-biomimetic. A biomimetic device mimics the human limbs in form and moves with them. An example is an exoskeleton.
The difficulty of developing biomimetic devices is a constraint in the case of biomimetic devices. In contrast to non-biomimetic devices, which are distinct from the human body, this issue does not exist for devices which replicate human movement and function for different body sizes without limiting freedom of movement.
Apart from form, force feedback equipment can be classified based on the direction of the applied power. Active and resistive devices are included in this classification. Active devices limit user movement and are driven by motors. They can simulate a wide range of interaction types and are generally robust but difficult to control. By using a brake, the latter limits user movement.
Feedback through vibrotactile sensations
Vibrotactile feedback targets the skin’s definite receptors that resemble onion layers, which can sense vibrations up to 1000 hertz and can apply pressure to the skin.
These devices are economical, simple, and easy to control and power. They are commonly found in cell phones, game controllers, automobile steering wheels, and smartwatches. It is difficult to miniaturize vibrating motors efficiently and they aren’t ideal for simulating a wide variety of sensations.
When interacting with a touchscreen, the user experiences a vibration similar to pressing a physical button.
Feedback through electrotactile stimulation
It is possible to generate a variety of sensations with electrotactile stimulators, some of which cannot be produced by other forms of feedback. These devices use electrical impulses to affect receptors and nerve endings.
It is possible to create different kinds of sensations by using this feedback methodology based on the frequency and intensity of the stimuli applied to the human skin. Sensations can occur based on voltage, current, waveforms, materials, contact forces, electrode sizes, and even the type of skin.
Unlike vibrotactile or force feedback systems, electrotactile feedback systems are not dependent on moving mechanical parts. Electrotactile displays are also distinguished by the assembly of electrodes into compact arrays for implementing these types of haptic devices. It is highly possible to simulate real-world sensations using haptic feedback since electrical signals serve as the basis of the human nervous system.
Tactile feedback using ultrasonic waves
With these devices, ultrasound emitters (high-frequency sound waves) generate subtle feedback through a process known as acoustic time reversal, where the emitter’s location may differ from the target.
If ultrasound feedback must be transmitted to large surface areas of the body, haptic feedback fields are useful. Several emitters are combined to create midair ultrasound interfaces that create turbulence that can be felt by the human skin. These interfaces are invisible but tangible.
This haptic technology has the advantage of not requiring user-worn accessories, but is less economical than other types of haptic feedback.
Feedback from the thermal system
Thermoelectric diodes that rely on the Peltier effect are used in thermal feedback haptics, which use actuator grids in direct contact with the human body. The simulation effect is not achieved by placing multiple tiny units or very precise stimulus placements.
As a result of the law of energy conservation, heat and cold cannot simply disappear from any surface and must be transferred accordingly. As a result, these devices can be extremely energy-intensive and complex since the transfer must take place swiftly to ensure accurate simulation.
In haptics, vibration is a standard modality. The eccentric rotating mass and linear resonant actuators discussed above fall under this category.
However, not every vibrating device can be categorized under haptics. The distinction lies in the intention and complexity of the vibration patterns. Regular vibrating devices usually emit a single waveform in a continuous, monotonous intensity for the duration of the communication. On the other hand, haptics uses advanced waveforms to convey information.
When a smartphone vibrates during a call, it is merely vibrating; this is a sensation that conveys general information rather than a specific intent. During a gaming session, on the other hand, a vibration of a specific intensity in a specific part of the device can indicate specific information, such as a collision in a racing game.
The kinesthetic sense
It simulates movement, mass, and shape by mounting haptics on the user’s body.
Simulated buttons replicate the sensation of a mechanized pressure pad under the user’s finger with the help of audio and haptic feedback.
The importance of haptics
The following are everyday use cases for haptic technologies in several industries.
Metaverse, no. 1
Technology news frequently mentions the term metaverse. It is skyrocketing in popularity, and companies across a wide range of industries are bracing for a revolution. Combined with the rise of the metaverse, haptics will be one of the most adopted technologies in this space.
The ultimate goal of the metaverse is to replicate reality in a virtual environment that is close to indistinguishable from the real world. For this collective vision of the tech industry to succeed, highly effective haptics are critical. Immersion across all human senses is essential, not just sight and sound.
The Facebook company announced its rebranding in October 2021, but it had been dealing with immersive technologies for years before that.
In 2014, Meta acquired Oculus for $2 billion, marking its first significant step toward haptics superiority. Since then, the company has been acquiring new augmented reality (AR) and virtual reality (VR) IPs and investing in building its own solutions. Haptics were discussed as early as 2019.
Earlier this year, Facebook Reality Labs (formerly Oculus Labs) announced haptics-enabled devices that reduce input latency during gaming.
In addition, haptics is a natural choice when it comes to interacting with virtual worlds realistically and without restrictions. With haptic tech, clunky user behavior (such as tapping on a touchscreen or pressing a button on a handheld remote control) is replaced with seamless zooming, pinching, pushing, touching, dragging, and other object-oriented interactions.
These interactions will be enabled by gear (most likely gloves) that will be powered by more than just haptics. They will also include electromyography (EMG) to translate electrical signals from the brain into inputs for computers.
If you were to use haptics in the metaverse, you would receive feedback or a reaction every time you provided input. For instance, a user pushing an object could feel its resistance and weight. If a rock were tossed across a virtual pond, users would feel it leave their fingers. That’s the magic of haptics!
Exploration of space
In addition to the metaverse, haptics has also made waves in space, with ground crews and astronauts using it for various applications.
The European Space Agency’s METERON project, which focuses on developing robot interfaces, communication networks, hardware, and software to control robots remotely in space, uses haptics extensively.
Robots controlled from Earth can also be used by space agencies to construct infrastructure on other planets or satellites using haptic technology. This may sound ambitious today; however, space agencies have already adopted complex haptics for existing space-related applications. Further developments are inevitable.
The aviation industry
Haptics in aviation enable flight crews to gain a swifter understanding of operational issues. For instance, steering equipment is infused with haptic technology to alert pilots to dangerous flight conditions.
In aviation, haptic feedback is used to improve the overall situational awareness of pilots and to notify them of airplane conditions even when there is no immediate danger. Pilots can, for example, use haptics to manage their flight regime safely and economically by providing information about flight control.
Haptic technology is also one of the solutions that help ensure compliance with flight envelope protection measures. Haptic actuators are mounted on various components within the cockpit and among the controls. Pilots interact with them physically and transmit the necessary information quickly and efficiently via these devices.
The use of haptics during flight simulations allows flight trainees to experience events they would otherwise only experience if they occurred in real life. In addition to live flight simulations, haptics-enabled simulators can simulate weather conditions such as rain, thunderstorms, and damaged engines as well.
Various vehicle user interface (UI) parts, such as the steering wheel, pedals, seatbelts, dashboard, and seat, can be enhanced with haptic components.
A vibrating seat, for instance, can alert the driver if pedestrians are likely to cross the road in front of them using these tactile interfaces.
Teleoperations by robots
In some cases, operators are notified in real-time about the forces the robot is being exposed to. This enables them to carry out tasks with accuracy and precision. Teleoperators rely on haptics to receive critical feedback from remote robotic tools. As an example, robots regularly manage toxic substances and defuse explosives.
The healthcare sector
A number of aspects of modern healthcare rely heavily on haptics, such as minimally invasive surgery. Using force and tactile feedback, doctors can examine tissues and diagnose abnormalities remotely and accurately through the controls of specialized laparoscopic tools.
A surgeon’s control over robotic procedures is enhanced by haptics. Doctors can use surgical robots to perform operations in spaces that are too small for human hands, with small tools, or even while sitting somewhere else in the world. Robotic teleoperations enhanced accuracy and reduced operating time when haptic feedback was added. Additionally, tissue damage was significantly reduced.
Also, haptics can be used to train medical practitioners. For instance, medical students can practice on virtual patients, gaining experience of actual incisions and suturing without risking another person’s welfare. Students can drill teeth and cut gums in virtual reality using dental simulators, with haptics simulating real-world sensations and outcomes.
The entertainment industry
In shopping malls and theme parks, haptics are used to simulate explosions, weather, and other environmental and human conditions in movie theater seats and immersive gaming sets. As video games strive to recreate the reality of virtual scenarios, gamepads, joysticks, jet seats, and steering wheels transmit electrotactile and force feedback to gamers.
In addition to gaming controllers and VR headsets, haptic technology also reaches home users. For example, anyone can buy haptic-powered vests online that deliver low frequencies to their bodies when worn. When consuming media such as video games and movies, these vests are combined with compatible home entertainment devices to enhance the sensations.
There are many different haptic configurations available, each with a specific set of applications. With the rapid popularization of the metaverse, haptic technology is only expected to expand across all walks of life. Nevertheless, haptics isn’t the only application. This technology is being used in medicine, entertainment, automobiles, and many other sectors as well.