Date: Tue, 26 Nov 1996 00:01:48 GMT Server: Apache/1.2-dev Connection: close Content-Type: text/html Last-Modified: Fri, 23 Aug 1996 03:00:48 GMT ETag: "5d870-cef-321d1ee0" Content-Length: 3311 Accept-Ranges: bytes Haptics

Haptics

-----

The haptics group at the MIT Artificial Intelligence Lab conducts research in a wide variety of topics related to touch perception and feedback including the development of devices to effect haptic stimulation and software to render the sensations of touch. The group is headed by Dr. Kenneth Salisbury. Another group headed up by Ken is the Vision and Touch Guided Manipulation group.

The people in the Haptics group are:


One of our first developments was the Phantom Haptic Interface (distributed by SensAble Devices, Inc.):

Touching is Believing


The PHANToM represents a new generation of computer input devices. More than just another passive, 3D mouse, the PHANTom allows users to actually feel virtual objects. Unlike buzzing tactile stimulators, the PHANToM actively exerts an external force on the user's finger tip - creating the illusion of interactions with solid virtual objects. Smoothe spheres, flat walls, sharp corners, and even texture can be convincingly conveyed to the human haptic sytem using the device. This is not a bulky exoskelatal device - one simply inserts his or her finger tip into the PHANToM and interacts with the virtual environment.


High Fidelity

The PHANToM contains 3 motors which control the x, y, and z forces exerted on the user's finger tip. Mounted on each motor is an optical encoder to determine the x, y, and z position of the user's finger tip. The torque from the motors is transmitted through a proprietary cable transmission to a stiff, light-weight linkage. At the end of this linkage is a passive, 3 degree of freedom gimbal attached to a thimble. The passive gimbal allows the thimble to rotate so that a user's finger tip may assume any comfortable orientation. The user's finger tip can then be modelled as a point or frictionless sphere within the virtual world. The device has low friction, low inertia, and no unbalanced weight so movements through free virtual space are unimpeded.


Versatility

The PHANToM is best described as a universal force-reflecting interface. In fact, a stylus can be substituted for the thimble. A user can then manipulate the stylus to control the tip of a virtual pencil or paint brush. Users can actually feel the tip of the stylus touch virtual surfaces. The PHANToM can be used as a high precision force-reflecting master for teleoperation or as a 3 DOF input device for CAD. Artists can mold clay within the computer and surgeons can practice procedures on virtual patients.


special-effects@ai.mit.edu