Chapter 1 Introduction.docx

CHAPTER 1 INTRODUCTION 1.1 What is ‘Haptic’ ? Haptic refers to technology that uses touch to control and interact with computers. A user may apply a sense of touch through vibrations, motion or force. Haptic technology is used mainly in creating virtual objects, controlling virtual objects or in the improvement of the remote control of machines and devices. The word haptic is derived from the Greek "haptikos," which means a sense of touch. Haptic technology refers to technology that interfaces the user with a virtual environment via the sense of touch by applying forces, vibrations, and/or motions to the user. This mechanical stimulation may be used to assist in the creation of virtual objects (objects existing only in a computer simulation), for control of such virtual objects, and to enhance the remote control of machines and devices (teleoperators). This emerging technology promises to have wide reaching applications as it already has in some fields. For example, haptic technology has made it possible to investigate in detail how the human sense of touch works by allowing the creation of carefully controlled haptic virtual objects. These objects are used to systematically probe human haptic capabilities, which would otherwise be difficult to achieve. These new research tools contribute to our understanding of how touch and its underlying brain functions work. Although haptic devices are capable of measuring bulk or reactive forces that are applied by the user, it should not to be confused with touch or tactile sensors that measure the pressure or force exerted by the user to the interface. Haptics is the technology of adding the sensation of touch and feeling to computers. When virtual objects are touched, they seem real and tangible. Haptics senses links to brain sensing position and moment of the body by means of sensory nerves within the muscles and joints. Haptics devices may join tactile sensor that measure forces exerted by the user on the interface. Haptic technology has made it possible to investigate how the human sense of touch works by allowing the creation of carefully controlled haptic virtual objects.

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Haptics = touch = connection. Touch is the code of personal experience. Of the live sense, touch is the most proficient, the only one capable of simultaneous input and output. 1

1.2 History One of the earliest applications of haptic technology was in large aircraft that use servomechanism systems to operate control surfaces. Such systems tend to be "one-way", meaning external forces applied aerodynamically to the control surfaces are not perceived at the controls. Here, the missing normal forces are simulated with springs and weights. In lighter aircraft without servo systems, as the aircraft approached a stall the aerodynamic buffeting (vibrations) was felt in the pilot's controls. This was a useful warning of a dangerous flight condition. This control shake is not felt when servo control systems are used. To replace this missing sensory cue, the angle of attack is measured and when it approaches the critical stall point, a stick shaker is engaged which simulates the response of a simpler control system. Alternatively, the servo force may be measured and the signal directed to a servo system on the control, known as force feedback. Force feedback has been implemented experimentally in some excavators and is useful when excavating mixed material such as large rocks embedded in silt or clay. It allows the operator to "feel" and work around unseen obstacles, enabling significant increases in productivity and less risk of damage to the machine. The first US patent for a tactile telephone was granted to Thomas D. Shannon in 1973. An early tactile man-machine communication system was constructed by A. Michael Noll at Bell Telephone Laboratories, Inc. in the early 1970s and a patent was issued for his invention in 1975. In 1994, Aura Systems launched the Interactor Vest, a wearable force-feedback device that monitors an audio signal and uses Aura's patented electromagnetic actuator technology to convert bass sound waves into vibrations that can represent such actions as a punch or kick. The Interactor vest plugs into the audio output of a stereo, TV, or VCR and the user is provided with controls that allow for adjusting of the intensity of vibration and filtering out of high frequency sounds. The Interactor Vest is worn over the upper torso and the audio signal is reproduced through a speaker embedded in the vest. After selling 400,000 of its Interactor Vest, Aura began shipping the Interactor Cushion, a device which operates like the Vest but instead of being worn, it's placed against a seat back and the user must lean against it. Both the Vest and the Cushion were launched with a price tag of $99. In 1995 Norwegian Geir Jensen described a wrist watch haptic device with a skin tap mechanism, termed Tap-in. It would connect to a mobile phone via Bluetooth. Tappingfrequency patterns would identify callers to a mobile and enable the wearer to respond by selected short messages. It was submitted for a governmental innovation contest and received no award. It was not pursued or published until recovered in 2015. The Tap-in device by Jensen was devised facing the user to avoid twisting of the wrist, see image. It would adapt across all mobile phone and watch brands. In 2015 Apple started to sell a wrist watch which included skin tap sensing of notifications and alerts to mobile phone of the watch wearer.

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1.3 Need of Haptic Gesture control is an increasingly common form of interface across many sectors, including desktop computers, gaming, interactive displays and automotive. However, in current gesture control systems, users can gesture, but they cannot feel the controls they are interacting with. A team of human computer interaction (HCI) researchers from Glasgow University decided to find out whether this mattered. Using Ultrahaptics’ mid-air haptic technology, Dr DongBach Vo and Professor Stephen Brewster put together a user study to determine whether adding haptic feedback to gesture controls would improve performance.

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1.4 Aim of Haptic &Future Haptic refers to technology that uses touch to control and interact with computers. A user may apply a sense of touch through vibrations, motion or force.Haptic technology is used mainly in creating virtual objects, controlling virtual objects or in the improvement of the remote control of machines and devices. Love, compassion, joy, affection, warmth… All our emotions come alive through the sense of touch. Be it the physical world or artificial, the sense of ‘reality’ is massively governed by touch. So, it is obvious that a better future will need a heightened response to touch stimuli. When Haptic Technology together with other promising innovations such as Virtual Reality, Augmented Reality, 3D Virtual Worlds and 3D Visualization rise to prominence, our entire perception of the world will be elevated to a whole new level of grandeur. Look around you. There is a masterful design in almost everything that we see around us. We may not really give due credit every time but every little thing that we see around is the end result of a creative design. From the pen in your hand to the water bottle, notepad, computer table and even the building you work in! Engineering, design, and architecture have played a great role in making the world as beautiful as today. It is going to look even better with efficient utilization of Haptic Technology. Characters wore gloves with feedback that let them feel the imaginary objects in their hands. They could upgrade to full body suits that reproduced the force of a punch to the chest or the stroking of a caress. And yet these capabilities, too, might not be as far off as we imagine. We rely on touch — or “haptic” — information continuously, in ways we don’t even consciously recognize. Nerves in our skin, joints, muscles and organs tell us how our bodies are positioned, how tightly we’re holding something, what the weather is like, or that a loved one is showing affection through a hug. Around the world, engineers are now working to recreate realistic touch sensations, for video games and more. Engaging touch in humancomputer interactions would enhance robotic control, physical rehabilitation, education, navigation, communication and even online shopping. “In the past, haptics has been good at making things noticeable, with vibration in your phone or the rumble packs in gaming controllers,” says Heather Culbertson, a computer scientist at the University of Southern California. “But now there’s been a shift toward making things that feel more natural, that more mimic the feel of natural materials and natural interactions.” Take surgical robots, which allow doctors to operate from the other side of the world, or to manipulate tools too small or in spaces too tight for their hands. Numerous studies have shown that adding haptic feedback to the control of these robots increases accuracy and 4

reduces tissue damage and operation time. Ones with haptic feedback also allow doctors to train on patients that exist only in virtual reality while getting the feeling of actual cutting and suturing.Getting a feel for what the robot under your command is doing would also be helpful for defusing bombs or extracting people from collapsed buildings. Or for repairing a satellite without suiting up for a spacewalk. Even Disney has looked into haptic telepresence robots, for safe human-robot interactions. They developed a system that has pneumatic tubes connecting a humanoid’s robotic arms with a mirror set of arms for a human to grasp. The person can manipulate the mirror bot to cause the first bot to hold a balloon, pick up an egg or pat a child on the cheeks. 1.5 Problem With Haptic Haptics is a recent enhancement to virtual environments, allowing users to "touch" and feel the simulated objects they interact with. Current commercial products allow tactile feedback through desktop interfaces (such as the FEELIt/sup TM/ mouse or the PHANToM/sup TM/ arm) and dextrous tactile and force feedback at the fingertips through haptic gloves (such as the CyberTouch/sup TM/ and the CyberGrasp/sup TM/). Virtual reality haptic programming requires good physical modeling of user interactions, primarily through collision detection, and of object responses, such as surface deformation, hard-contact simulation, slippage, etc. It is at present difficult to simulate complex virtual environments that have a realistic behavior. This task is added to by the recent introduction of haptic toolkits (such as Ghost/sup TM/ or VPS). Current technology suffers from a number of limitations, which go beyond the higher production cost of haptic interfaces. These technical drawbacks include the limited workspace of desktop interfaces, the large weight of force-feedback gloves, the lack of force feedback to the body, safety concerns, etc. Not to be neglected is the high bandwidth requirement of haptics, which is not met by current Internet technology. As a result, it is not possible at present to have a large number of remote participants interacting haptically in a shared virtual space.

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CHAPTER 2 LITERATURE REVIEW

2.1 BASIC CONCEPTS OF HAPTICS The haptic system can sense and act on the environment while vision and audition have purely sensory nature. Haptics means the combined sensation of mechanical, thermal and noci-perception (fig.1). As a result haptics consists of nocio-receptive, thermoceptive, kinaesthetic and tactile perceptions. The sense of balance takes an exceptional position as it is not counted among the five human senses having receptors of their own. Yet, it really exists making use of all other senses’ receptors, especially the haptic ones. Unlike the four other senses (sight, hearing, taste, and smell), the sense of touch is not localized to a specific region of the body; instead, it is distributed across the entire body through the touch sensory organ, our skin, and in our joints, muscles, and tendons. The sense of touch is typically described as being divided into two modalities: kinesthetic and tactile. Kinesthetic sensations, such as forces and torques, are sensed in the muscles, tendons, and joints. Tactile sensations, such as pressure, shear, and vibration, are sensed by specialized sensory end organs known as mechanoreceptors that are embedded in the skin. Each type of mechanoreceptor senses and responds to a specific type of haptic stimulus.

Fig.-Distribution of senses

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2.2 TERMINOLOGY USED IN HAPTIC SYSTEMS Some technical terminology used in haptic systems is listed below and illustrated via block diagrams. The arrows between the components of the block diagrams remain unlabeled as because they may represent different kinds of information depending on the devices they refer to. Haptic devices are capable of transmitting elongations, forces and temperature differences and in a few realizations they also stimulate pain receptors. The terms “system” and “device” and “component” are not defined on an interdisciplinary basis. Dependent on one’s point of view the same object can be e.g. “a device” for a hardware-designer, “a system” for the software-engineer, or “just a component” for another hardware-engineer. A. A haptic device is a system generating an output which can be perceived haptically. It has (figure. 2) at least one output, but not necessarily any input. The tactile markers on the keys F and J of a keyboard represent information for the positioning of the index finger. By these properties the keys are already tactile devices. At a closer look the key itself shows a haptically notable point of actuation, the haptic click. This information is transmitted in a kinaesthetic and tactile way by the interaction of the key’s mechanics with the muscles and joints and the force being transmitted through the skin. Such a key is a haptic device without a changing input and two outputs. B. A user (in the context of haptic systems) is a receiver of haptic information. C. A haptic controller describes a component of a haptic system for processing haptic information flows and improving transmission.

Fig – Haptic Device,user and controller

D. Haptic interaction describes the haptic transmission of information. This transmission can be bi- or unidirectional (fig. 3). Moreover, specifically tactile (unidirectional) or kinaesthetic (uni- or bidirectional) interaction may happen. A tactile marker like embossed printing on a bill can communicate tactile information (the bill’s value) as a result of haptic interaction.

E. The addressability of haptic systems refers to the subdivision of an output signal of a device (frequently a force) or of the user (frequently a position). F. The resolution of a haptic system refers to the capability to detect a subdivision (spatial or temporal) of an input signal. With reference to a device this is in accordance with the measuring accuracy.With respect to the user this corresponds to his perceptual resolution.

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G. A haptic marker refers to a mark communicating information about the object carrying the marker by way of a defined code of some kind. Examples are markers in Braille on bills or road maps. H. A haptic display is a haptic device permitting haptic interaction, whereby the transmitted information is subject to change (fig. 4). Purely tactile as well as kinaesthetic displays are available.

Fig – Haptic Display

I. A tactor is a purely tactile haptic display generating a dynamic and oscillating output. They usually provide a translatory output, but could also be rotatory. J. A haptic interface devices are those that measure the motion of, and stimulate the sensory capabilities within, our hands and thus permitting a haptic interaction (Figure: 5). A haptic interface always refers to data and device.

Fig – Haptic Interface

K. Force-Feedback (FFB) refers to the information transmitted by kinaesthetic interaction (fig. 5). This term is widely used in advertising and numerous commercial products like FFB-joysticks, FFB-steering wheels and FFB-mice. L. A haptic manipulator is a system interacting mechanically with objects whereby continuously information about positions in space and forces and torques of the interaction is acquired. 2.3 HAPTIC TECHNOLOGIES Tactile cues include textures, vibrations, and bumps, while kinesthetic cues include weight, impact, etc. In the following section, we present some crucial concepts and terminology related to haptics. Haptic: the science of applying tactile, kinesthetic, or both sensations to human computer interactions. It refers to the ability of sensing and/or manipulating objects in a natural or synthetic environment using a haptic interface. Cutaneous: relating to or involving the skin. It includes sensations of pressure, temperature, and pain. Tactile: pertaining to the cutaneous sense, but more specifically the sensation of pressure rather than temperature or pain. Kinesthetic: relating to the feeling ofmotion. It is related to sensations originating in muscles, tendons, and joints. Force Feedback: relating to the mechanical production of information that can be sensed by the human kinesthetic system. 8

Haptic communication: the means by which humans and machines communicate via touch. It mostly concerns networking issues. Haptic device: is a manipulator with sensors, actuators, or both. A variety of haptic devices have been developed for their own purposes. The most popular are tactilebased, pen-based, and 3 degree-of-freedom (DOF) force feedback devices. Haptic interface: consists of a haptic device and software-based computer control mechanisms. It enables human–machine communication through the sense of touch. By using a haptic interface, someone can not only feed the information to the computer but can also receive information or feedback from the computer in the form of a physical sensation on some parts of the body. Haptic perception: the process of perceiving the characteristics of objects through touch. Haptic rendering: the process of calculating the sense of touch, especially force. It involves sampling the position sensors at the haptic device to obtain the user’s position within the virtual environment. Haptic rendering is, therefore, a system that consists of three parts, a collision detection algorithm, a collision response algorithm, and a control algorithm. Sensors and Actuators: a sensor is responsible for sensing the haptic information exerted by the user on a certain object and sending these force readings to the haptic rendering module. The actuator will read the haptic data sent by the haptic rendering module and transform this information into a form perceivable by human beings . Tele-haptics: the science of transmitting haptic sensations from a remote explored object/environment, using a network such as the Internet, to a human operator. In other words, it is an extension of human touching sensation/capability beyond physical distance limits. Tele-presence: the situation of sensing sufficient information about the remote task environment and communicating this to the human operator in a way that is sufficient for the operator to feel physically present at the remote site. The user’s voice, movements, actions, etc. may be sensed, transmitted, and duplicated in the remote location. Information may be traveling in both directions between the user and the remote location. Virtual Reality (VR): can be described as the computer simulation of a real or virtual (imaginary) world where users can interact with it in real time and change its state to increase realism. Such interactions are sometimes carried out with the help of haptic interfaces, allowing participants to exchange tactile and kinesthetic information with the virtual environment. Virtual environment (VE): is an immersive virtual reality that is simulated by a computer and primarily involves audiovisual experiences. Despite the fact that the terminology is evolving, a virtual environment is mainly concerned with defining interactive and virtual image displays. Collaborative virtual environments (CVE): is one of the most challenging fields in VR because the simulation is distributed among geographically dispersed computers. Potential CVE applications vary widely from medical applications to gaming. Collaborative haptic audio visual environment (C-HAVE): in addition to traditional media, such as image, audio, and video, haptics – as a new media – plays a prominent role in making virtual or realworld objects physically palpable in a CVE. A C-HAVE allows multiple users, each with his/her own haptic interface, to collaboratively and/or remotely manipulate shared objects in a virtual or real environment and is shown in fig.

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Fig: Haptic Visual Environment

It is a process of applying forces to the user through a force-feedback device. Using haptic rendering, we can enable a user to touch, feel and manipulate virtual objects. Enhance a user’s experience in virtual environment. Haptic rendering is process of displaying synthetically generated 2D/3D haptic stimuli to the user. The haptic interface acts as a twoport system terminated on one side by the human operator and on the other side by the virtual environment. Contact Detection: A fundamental problem in haptics is to detect contact between the virtual objects and the haptic device (a PHANTOM, a glove, etc.). Once this contact is reliably detected, a force corresponding to the interaction physics is generated and rendered using the probe. This process usually runs in a tight servo loop within a haptic rendering system.

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