client: DEKA Integrated Solutions Corp. (DARPA's Revolutionizing Prosthetics Program)
the prosthetic haptic interface system was developed as part of DARPA's Revolutionizing Prosthetics program to return the sense of touch to amputees, and refine the control mechanism used for high-level upper limb prosthetic devices by enabling the amputee to have sensory input and thereby accomplish two things:
no longer only rely on visual input alone for sensory feedback in grasping and manipulation;
provide heretofore absent exteroception - i.e., sensing of environmental - variables such as, vibration, surface texture and friction.
by providing the user with sensory input via haptic tactors that convey pressure, vibration, and shear, the prosthetic user will be informed of his/her tactile environment in addition to vision and therefore respond with motor output that is superior to what is allowed with current technology. Furthermore, the effect of applying haptic cues to an amputee’s reinnervated skin in response to functional exploratory tasks will improve his sense that the artificial limb is part of his body. (Increase the perceived correlation between his phantom limb and his prosthetic limb.)
in the intact arm, haptic sensing and motor control work in close coordination. For example, haptic feedback allows the motor system to control grip strength, ensuring that fragile objects are not crushed, and that objects of all different weights, sizes and shapes can be held and not dropped. The cutaneous sensors in the skin of the fingertips are especially important in this regard.
our objective on this project was to provide amputees with a haptic prosthesis; a set of artificial senses that enable intuitive and effective control of grip strength. kuiken’s reinnervation technique provides such an opportunity. In the process of reinnervating muscles, Kuiken demonstrated reinnervation of cutaneous afferents.
the prosthetic haptic interface system is composed of three major subcomponents. These being:
fingertip sensor - this sensor is mounted on the 'fingertip' of a prosthetic hand and senses forces and accelerations imparted at the fingertip while the user interacts and/or grasps different object. with this information the sensation of graded pressure, and differing textures and/or surface frictions can be artificially recreated.
haptic tactor - displays the artifically recreated forces, textures, and friction 'felt' (sensed) by the fingertip sensor. (For more information see publication titled On the Design of Miniature Haptic Devices for Upper Extremity Prosthetics; IEEE-ASME Transactions on Mechatronics; Feb. 2010)
embedded controller system - the controller is the brains of the system, here the signals from the fingertip sensor are translated into command signals that recreate the haptic sensations at the haptic tactor.
see gallery for pictures of these subcomponents.
the pictures and videos below show the evolution of the fingertip sensor and the haptic tactor that were developed for use by target reinnervated patients (TRI) under the DARPA's Revolutionizing Prosthetics program. Although, TRI patients were the motivation for this haptic system, it can also be used and provide functional feedback to all amputees.
- for a video demo of the 1-dof tactor prototype, click here.
- for a short video of the 2-dof tactor going through it's motions, click here.
kinea Design is proud to participate with other technology leaders, including the Rehabilitation Institute of Chicago Neural Engineering Center for Artificial Limbs laboratory, and Liberating Technologies, Inc., on the ground-breaking Revolutionizing Prosthetics Program 2007 under the direction of Deka Research & Development Integrated Solutions Division.
The Revolutionizing Prosthetics 2007 is funded by the Defense Advanced Research Projects Agency (DARPA).