Abstract

Haptic Technologies are becoming a larger part of the engineering design process today.  They are a part of everything from interfaces to operational necessities of microsurgeries.  Haptic technologies are everywhere in today’s market from cell phones and entertainment systems, to flight controls and medical devices.  There are many different types of haptic technologies.  This article mostly focuses on motor-based haptic actuators, but also touches on pneumatic and tactile systems as well.  This article goes over the basics of what haptic technology is, how it relates to the ECE field, and its application to modern technology.

Introduction

What is Haptic Technology?

Haptic technology is the science, technology, and applications associated with information acquisition and object manipulation through touch.  The word haptic originates from the Greek “Haptikos” which means tactual, or of or connected with the sense of touch (Kurita, 2014).  Haptic technology is everywhere.  The small vibration of a cell phone in response to a touch event is an example of haptic feedback at work. The resistance of a joystick that controls a fighter jet, as it provides a tactile feedback to the pilot, is another example of haptic feedback.  One of the most common forms of haptic feedback is vibration, such as the vibration of video game controllers that add an extra layer of immersion to the simulation being played.  However, pneumatic and tactile technologies have also entered the haptic technology space.  Pneumatic actuators use a system of pressurized tubes to send a response to the user.  Tactile technologies use texture to elicit specific responses from the user (Kurita, 2014).

Why Is Haptic Technology Relevant?

Haptic feedback provides information to one of the five basic senses of the human body: touch.  Most technology today is visual or auditory, but that only applies to two of the 5 senses.  Because of this, the presence and advancement of haptic technology is very important. Haptic technology can be helpful to a variety of situations.  The vibrations of touch screens help us know that we have pressed a button in an otherwise purely visual environment.  Haptic technology can be used to provide useful tactile feedback to people running simulations, or operating equipment from afar (Garre, 2010).  Haptic technologies can also help add context to a virtual environment.  Subtle tactile stimulus can be used to make a virtual environment feel more real, and therefore immerse the user in the technology they are using (Kurihara, 2014).

Relevance To ECE

Hardware and software professionals in Electrical and Computer Engineering build most haptic technology.  The drivers for the actuators of the feedback need to be built and programmed in a way that provides meaningful stimulus to the users.  This involves both hardware and software development.  The logic behind the stimulus trigger and the user interface of the device must also be programmed or built (Kurita, 2014).

Standard haptic actuators are built with embedded electrical motors.  An electrical signal is sent to the motor telling it to vibrate at a specific rate.  The rate is adjustable and can be configured for a variety of patterns.  In order to control the motor, a logical circuit component is needed.  This could be hard wired in terms of set voltages and transistors, but these days it is better to get a prefabricated chip.  Power is also needed in order to drive the motor.  For all this to happen, an Electrical or Computer Engineer is needed.  An Electrical or Computer Engineer can prototype and manufacture a chip to drive the motor, as well as the system to power the motor.  Hardware is only one part of ECE’s roll in haptic technologies.

People in the ECE field also are in charge of programming the devices they design.  Haptic technologies must be programmed to be intuitive and responsive so that they appeal to the user’s tactile senses.  To do this, the programmer must gather user data on how other people interact with current or prototype technologies.  Human Factors engineers are invaluable resources to use in this stage of development, as they can help gather, and assess user data.  Using that data, they redesign the User Interface and try to match the haptic input to the audiovisual display being presented to the user.  An example of tailored haptic interaction is smart phone vibration patterns.  Different applications have unique vibration patterns that are set off when the user receives a notification. The unique vibration pattern lets the user know tactilely what new information their device has received.  People in the ECE field are necessary to make haptic technologies function the way they are expected to.

ECE is influential in non-vibration based haptic technologies as well.  Some haptic technologies are driven by pneumatic tubes, rather than by electric motors (Li, 2014). While the mechanism is different, the principle remains the same.  The engineer has to design a circuit to control the pneumatic actuators, instead of the motor.  The engineer then must program the circuit to manipulate the air pressure to obtain the desired tactile output.

Enhancing User Experience

User Interface

Common haptic technology used today involves the vibration of a device in response to an input event (Kurita, 2014).  A common example of this is the cell phone.  A phone set to vibrate notifies the user that someone is calling them via the tactile stimulus of vibration.  Touch devices like tablets and smart phones vibrate in response to touch events.  Some are built with fewer vibration actuators and vibrate no matter where the user presses.  Other devices vibrate at the specific coordinate that the user presses by using a system of actuators.  This advanced level of feedback provides greater assurance to the user that they pressed in the correct place, and lets them use their device with more ease (Asque, 2014).

A developing haptic technology is the usage of pneumatic input.  This system uses a series of compressible pneumatic tubes that provide a base pressure.  The tubes are small enough that they can be arranged in any sort of configuration.  Like how pixels on a screen form an image, these pneumatic tubes can form a three dimensional shape for the user to place their fingertips on. This is currently being used to relay tactile data to the fingertips of doctors trying to detect tumors.  By using a combination of imaging techniques and haptic technologies, the technician is able to feel inside the patient’s brain and find tumor sites by locating the abnormality tactilely (Li, 2014). More responsive, configurable, and uniquely shaped interfaces can be created with this emerging technology.

The materials used to create a device, as well as its structure also fall under the realm of haptic technologies (Baumgartner, 2015). Different materials can elicit different responses from users, both physically and mentally.  Texture, temperature, friction, responsiveness are all factors to keep in mind when developing technology that will interface with a user.  The way the buttons feel on a keyboard was designed by an engineer to be pleasing to the user.  The responsiveness of a touchpad, or the way that it clicks is another example of tactile design in action.  The smoothness of the surface allows for the user to glide across their screen while the assured clicking of the touchpad lets them know decisively that they have clicked. The tactile nature of haptic technologies is very important to consider when creating user interfaces.

Teleoperation

Teleoperation is the process of operating a device over a distance.  The key factor in teleoperation is knowing the status of the device that is being operated in order to know that it is being operated correctly and make adjustments accordingly (Park, 2004). Normally this can be done with a series of audiovisual cues and alarms that signal the status of the device and warn the user if something is wrong.  The problem with this however, is that this only addresses two of the user’s senses.  With the addition of haptic feedback, an operator can respond faster to changes in the remote device’s environment.  What’s more, the haptic feedback can be built directly into the control system (Figure 1 (b)).  Actions that are to be avoided can create feedback, or resistance in the controls.  This form of negative feedback naturally melds with the process of interacting with the controls, rather than being a notification or cue off to the side.  Normally, pilots can use the tactile resistance of a plane’s controls to help them make small adjustments to stay on course.  Now drone pilots can use the simulated haptic feedback coming from the remote controls to correct their steering when piloting drones remotely (Clarke, 2014).

medicalOperation

Figure 1 (a) Standard Operation of Medical Device

teleoperation

Figure 1 (b) Teleoperation of Medical Device

Augmented Reality

Augmented reality is becoming more and more popular these days (Kurihara, 2014). Augmented reality is technology that provides an interactable overlay on everyday life.  Google Glass, Oculus Rift, and Microsoft’s Hololens are prime examples of virtual and augmented reality platforms.  Visual augmented reality provides a new way of adding interactive environments to everyday life.  However, there is a particular disjoint interacting with these virtual objects, because there is no tactile response.  A user may be able to pick up a virtual ball and play with it, but without the sensation of actually feeling it they are very aware that it is just a simulation.  With haptic technology, and existing visual technology, augmented reality can be enhanced to provide physical reactions to a semi virtual environment.  Haptic technology can be worn in addition to the augmented reality devices (Kurihara, 2014).  With this wearable haptic technology, the user can experience touch sensations that correspond to objects they are interacting with in the virtual overlay on their world.

Warped Perception

Using haptic technologies can have an interesting effect on the human mind.  One study used haptic feedback and audiovisual stimulation to make it seem as though the operator’s arm was a robotic arm. Industrial and mechanical noises were played along with an overlaid animation of the user with a robotic arm instead of his actual arm.  At the same time haptic feedback was applied to his “robot” arm that corresponded with the audiovisual cues.  The haptic feedback provided to them was enough to alter their perception to make them feel that they actually did have a robotic limb (Kurihara, 2014).  Haptic technology can be used not only for augmented reality, but also to create an altered perception of reality.

Medical Applications

Haptic technology has many useful applications in the medical field.  Haptic feedback combined with a combination of teleoperation and miniaturization can help surgeons perform advanced surgery at a very small scale (Park, 2004).  Medical equipment in general can be built to be more intuitive with the addition of haptic feedback. The technology can be built to be more responsive, and also have greater precision and safety measures with the addition of haptic technologies (Díaz, 2014).  Haptic technologies have also shown to help people with disabilities recover faster during physical therapy (Placidi, 2013).

Market For Haptic Technology

At Home

Haptic technologies can be used for a variety of applications at home.  Today many people already use haptic technology in their entertainment systems.  All modern day controllers have a built in vibration unit that provides stimulus when an in game vibration occurs for an extra layer of immersion in the simulation.  Additionally, the gyroscopes built in to some modern day controllers are used in conjunction with the vibration modules to provide a tactile sense of manipulating a three dimensional object, such as rotating a key to the correct position in a lock.  There is a market for at-home haptic technology that uses augmented reality and teleoperation.

Professional

Haptic technologies in the work environment can lead to greater productivity.  Teleoperation can be made more user friendly and efficient with haptic technology. The additional touch sensations can trigger built in reflexes that can be acted on without thinking, increasing response time while operating.  Augmented reality interfaces enhanced with tactile feedback can be used to create systems we haven’t even dreamed of yet.  Entirely virtual environments can be placed on top of our world that we will be able to go up to and physically interact with.  Microsurgery is possible and more efficient because of the haptic feedback provided to surgeons by their devices.

Issues With Haptic Technology

Limitations

Haptic feedback does have its drawbacks.  The drivers of the devices are limited in their response in magnitude, timing and precision.  The size of the haptic technology affects the magnitude and precision of the feedback possible.  Precision is also affected by the placement of the actuators as well as the coordination of the actuators being the used to drive a single stimulus.  There is also going to almost always be delay in the feedback response.  A delayed response has a negative impact on the intuitiveness of the device.  If a user is notified tactilely that they pressed a button after they press it instead of while they pressed it, it will break the illusion that they are pressing a real button (Díaz, 2014).  If there are delays in the pneumatic system, key areas of interest might be overlooked when examining a patient’s brain (Li, 2014).  Delays can be minimized through efficient hardware and software design, but will always exist in some capacity.

Similar Technologies More Efficient

Some forms of physical therapy have proven more cost effective than the current methods of haptic technology based physical therapy (Placidi, 2013).  Methods using a combination of image processing and visualizations have shown to have comparable results to similar haptic rehabilitation technologies.  Future manufactured haptic technology may prove to be more cost effective.

Conclusion

Haptic technologies provide tactile stimulation to interfaces, allowing for an enhanced user experience.  This technology is present in many of the devices used today, from teleoperated surgery and augmented reality interfaces to the vibrations of a common cell phone.  ECE is at the forefront of haptic technology development, creating the software and hardware that makes up modern haptics.  With the new developments in haptic technology, technologies of science fiction could become science fact.

Bibliography

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