I have been studying haptic interaction in both single user and collaborative virtual environments for over a decade now and the possibilities that the support for the touch modality can bring to computer interfaces never cease to amaze me. The number of application areas utilizing haptic feedback is currently increasing like never before and so is the basic research. In a series of blog posts, starting with this one, I will discuss some of the application areas where haptic feedback is currently showing great potential as well as a few areas where this potential has not yet been clearly shown. Where appropriate, I will of course provide examples from my own research within this field.
But, let’s start from the beginning before delving into specific application areas. The sense of touch is very complex and is based on thousands of receptors both in the skin (tactile perception) and in muscles and joints (kinesthetic perception). The skin receptors can detect e.g. pressure, pain and temperature and the others can detect e.g. stretching of muscles and movement of limbs and joints. Haptic perception is a combination of tactile and kinesthetic perception. I will not go into any more detail about the basics of the sense of touch in this blog post, but if you want to know more you can find an excellent review article here.
A haptic computer interface is an interface which we can interact with through the sense of touch. This is e.g. made possible by simulating contact forces as the user interacts with virtual objects through special hardware. In my own research I have often developed virtual environments by which one can interact by using the Phantom Omni haptic device shown in the picture above. The device functions as a kind of advanced 3D pointing device, where the pen-like handle, attached to robotic arms, is used to move a proxy in the virtual world. When the proxy gets in contact with an object in the virtual world, contact forces are generated simulating contact with the object. In these kinds of interfaces it is not only possible to simulate stiffness, textures, friction, etc. but also force fields, weight and inertia (there are interfaces, some of which I have developed myself, in which you can utilize a button on the device to “grab” a virtual object and move it around in an interface!). To top it all off you can also develop collaborative haptic interfaces, where contact between two or more proxies is simulated! I have developed several of these interfaces myself, including functions for joint handling of objects (making it possible for two users to feel each other’s forces on the jointly held object)!
Above, I have just touched upon the concept of haptic feedback and how it can be used in computer interfaces. In upcoming blog posts I will write about specific application areas where this kind of feedback can be utilized. More information about the basics of the sense of touch and computer haptics as well as pointers to important references within these areas can be found in my thesis.