Haptic Technology

Haptic Technology

In

Surgical Simulation and Medical Training.

A touch revolution.........

ABSTRACT

Engineering as it finds its wide range of application in every field not an exception even the medical field. One of the technologies which aid the surgeons to perform even the most complicated surgeries successfully is Virtual Reality.

Even though virtual reality is employed to carry out operations the surgeon's attention is one of the most important parameter. If he commits any mistakes it may lead to a dangerous end. So, one may think of a technology that reduces the burdens of a surgeon by providing an efficient interaction to the surgeon than VR. Now our dream came to reality by means of a technology called "HAPTIC TECHNOLOGY".

Haptic is the "science of applying tactile sensation to human interaction with computers". In our paper we have discussed the basic concepts behind haptic along with the haptic devices and how these devices are interacted to produce sense of touch and force feedback mechanisms. Also the implementation of this mechanism by means of haptic rendering and contact detection were discussed.

We mainly focus on 'Application of Haptic Technology in Surgical Simulation and Medical Training'. Further we explained the storage and retrieval of haptic data while working with haptic devices. Also the necessity of haptic data compression is illustrated.

Haptic Technology

Introduction:

Haptic, is the term derived from the Greek word, haptesthai, which means 'to touch'. Haptic is defined as the "science of applying tactile sensation to human interaction with computers". It enables a manual interaction with real, virtual and remote environment. Haptic permits users to sense ("feel") and manipulate three-dimensional virtual objects with respect to such features as shape, weight, surface textures, and temperature.

A Haptic Device is one that involves physical contact between the computer and the user. By using Haptic devices, the user can not only feed information to the computer but can receive information from the computer in the form of a felt sensation on some part of the body. This is referred to as a Haptic interface.

In our paper we explain the basic concepts of 'Haptic Technology and its Application in Surgical Simulation and Medical Training'.

Haptic Devices:

Force feedback is the area of haptics that deals with devices that interact with the muscles and tendons that give the human a sensation of a force being applied--hardware and software that stimulates humans' sense of touch and feel through tactile vibrations or force feedback.

These devices mainly consist of robotic manipulators that push back against a user with the forces that correspond to the environment that the virtual effector's is in. Tactile feedback makes use of devices that interact with the nerve endings in the skin to indicate heat, pressure, and texture. These devices typically have been used to indicate whether or not the user is in contact with a virtual object. Other tactile feedback devices have been used to stimulate the texture of a virtual object.

PHANToM and CyberGrasp are some of the examples of Haptic Devices.

PHANToM:

A small robot arm with three revolute joints each connected to a computer-controlled electric DC motor. The tip of the device is attached to a stylus that is held by the user. By sending appropriate voltages to the motors, it is possible to exert up to 1.5 pounds of force at the tip of the stylus, in any direction.

CYBER GRASP:

The CyberGlove is a lightweight glove with flexible sensors that

accurately measure the position and movement of the fingers and wrist. The CyberGrasp, from Immersion Corporation, is an exoskeleton device that fits over a 22 DOF CyberGlove, providing force feedback. The CyberGrasp is used in conjunction with a position tracker to measure the position and orientation of the fore arm in three-dimensional space.

Haptic Rendering:

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 two-port 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.

Another technique for contact detection is to generate the surface contact point (SCP), which is the closest point on the surface to the actual tip of the probe. The force generation can then happen as though the probe were physically at this location rather than within the object. Existing methods in the literature generate the SCP by using the notion of a god-object, which forces the SCP to lie on the surface of the virtual object.

APPLICATIONS