“Haptic interfaces, such as force feedback and tactile devices, offer the opportunity to present dynamic visualizations in a non-visual manner to the sense of touch: whether the data being visualized is real-time stock exchange data in the form of a graph, maps from route-finding applications, or the progress of a multiplayer on-line game.” (Wall and Brewster, 2005)
Haptic feedback has been used in broad area of research spanning various disciplines like tele-operation, 3D surface generation, Braille systems, virtual reality laboratory environments, gaming and much more. The sense of touch is used to provide feedback to the user about various object position and shape. This maybe making contact with a virtual object Morris and Joshi (2004), or providing visually impaired people with information about object shape and size by feeling the object’s edges.
Massie and Salisbury describes the PHANToM haptic interface (Figure 15) - a device that measures a user’s fingertip position and exerts a precisely controlled force vector on the fingertip (Massie and Salisbury, 1994). The device enables users to interact with and feel a wide variety of virtual objects and will be used for control of remote manipulators. Morris and Joshi used force-feedback haptic display to haptically render a three-dimensional surface that represents key aspects of a visual scene (Morris and Joshi, 2003). They also rendered depth and contour information with the Phantom, and also captured optic flow and present this to the user using sound cues. This helped visually impaired users explore the ‘visual’ world.
The use of touch-based interfaces to provide new computer interaction techniques for visually impaired people and those with physical disabilities have been an important area of research. The work by Sj¨ostr¨om deals with haptic interfaces that can be used with many different kinds of computer programs for blind people (Sj¨ostr¨om, 2001). This helps them perform various challenging tasks like understanding objects (by feeling the outline of an object and thus its shape and size), finding objects and searching for navigation assistance using easy reference points. Since visual impairment makes data visualisation techniques inappropriate for blind people, Yu et al. developed a system that makes graphs accessible through haptic and audio media (Yu et al., 2001).
McGee et al. demonstrates that through force feedback, texture information in virtual environments can be provided as the user can feel the roughness/smoothness (McGee et al., 2001).
Figure 15: PHANToM haptic interface invented by Thomas Massie
Nikolakis et al. used the PHANToM to create a user-friendly haptic environment that allowed blind or visually impaired people to access interactive presentations based on HTML web pages (Nikolakis et al., 2004). Here audio and haptics were combined to provide users with an interactive interface for reading HTML pages via sound and touch.
Kaklanis et al. extended this work to develop the 3D HapticWebBrowser which is a framework that allows haptic navigation through the Internet in addition to the haptic exploration of conventional 2D maps found on the web (Kaklanis et al., 2010). Kuber et al. provides a design guidance that could be used as a standard reference tool for Web designers wanting to develop an accessible browsing application, using the benefits offered by a force-feedback mouse (Kuber et al., 2011).
The performance of surgical knot tying is enhanced while using haptic feedback as compared to knots tied without feedback (Bethea et al., 2004). Agus et al. discusses a haptic and visual simulation of a bone-cutting burr that is being developed as a component of a training system for temporal bone surgery (Agus et al., 2003). For performing complex activities like a robotic surgery, the ability to feel the parts (via forced feedback) as the robotic arm is used by a surgeon operating from a different location is very useful. This ensures that although the surgeon can see on the screen what he/she is touching, the forced feedback lets the surgeon actually feel what is being touched.
Figure 16: Haptic Pen: a tactile feedback stylus
Realistic kinesthetic and tactile cues in a computer generated environment can be re-ceived by integration of haptic technology into such systems. Integration of haptic feedback has been popular in gaming. People can get a higher sense of immersion and interesting ways to interact with the game environment by integration of haptics into such video games. HaptiCast is using haptic interaction and effects in 3D games (Andrews et al., 2006). Here players assume the role of a wizard with an arsenal of haptically-enabled wands which they may use to interact with the game world. Morelli describes how haptic/audio based exergames (video games that are also a form of exer-cise) can be used by visually impaired individuals (Morelli, 2010).
Haptic Battle Pong is a competitive networked game that makes extensive use of three-degree-of-freedom force-feedback and six-three-degree-of-freedom input (Morris and Joshi, 2004). Force-feedback is used here to haptically display contact between a ball and a paddle. Houten et al. in their study evaluated a device to encourage seat belt use by applying haptic feedback (Houten et al., 2011). Whenever unbuckled drivers exceeded preset speed limit criteria without buckling their seat belts, there was an increase in the accelerator pedal back force. When the drivers fastened their seat belt, this counterforce was removed.
The Haptic Pen is a simple device that provides tactile feedback for multiple simul-taneous users that can work on large touch screens (Figure 16) (Lee et al., 2004). A pressure-sensitive stylus is combined with a small solenoid to generate a wide range of
tactile sensations. Brewster and Brown introduce a new form of icon which integrates tactile feedback called a Tacton. Tactons, or tactile icons, are structured tactile mes-sages that can be used to communicate message to users non-visually (Brewster and Brown, 2004). The parameters that can be included to create a Tacton are: frequency, amplitude, waveform and duration of a tactile pulse. The body location is also a key feature as different parts of the body have different response to the sense of touch.
We have seen that haptic feedback is used in a wide variety of applications and is inte-grated into various fields of research where the user can feel the provided information.
We now highlight the key benefits of haptic feedback.