Tactile feedback is essential for dexterous use of the hand. Physical therapists working to rehabilitate hands with neurological damage understand that tactile sensation is a key indicator of ultimate hand function. Neurophysiologists have identified that rapid reflexive adjustment of grip is essential for handling objects and depends on tactile feedback via the spinal cord. Autonomous robots can deal only with rigid objects in known orientations specifically because they lack tactile feedback. Engineers developing telerobotic manipulators have demonstrated improved performance when vibrotactile feedback is provided via """"""""haptic displays"""""""" to the operator's hand. The limiting factor in all of these applications has been the absence of sensitive yet robust sensors that can be incorporated into anthropomorphic mechatronic fingers and used in the diverse and often hostile environments in which hands need to function. We have developed and demonstrated the basic feasibility of novel biomimetic tactile sensors that provide wide dynamic range sensing of normal and shear forces, microvibrations associated with slip and texture, and temperature and heat fluxes associated with the material properties of contacted objects All of these sensing elements and connections are located in and protected by the rigid core of a finger that is covered with skin, pulp and nail elements that are mechanically and cosmetically similar to biological fingers. In this project, the signal processing electronics and molded core and skin components that were developed in Phase I will be assembled into complete modules. These DigiTAC"""""""" modules will be integrated mechanically, electronically and functionally into a variety of prosthetic and robotic hands intended to provide function for patients with loss of normal hand function as a result of trauma and disease. Tactile feedback from these multimodal sensor arrays will be used to adjust grip forces automatically to prevent slip and to stimulate innervated skin to provide conscious perception of interactions with objects.
Between 1988 and 1996 alone over 700,000 people underwent upper limb amputation (Dillingham et al. 1998). The development of electromechanical replacement limbs has been hampered by the lack of robust sensors for touch and grip adjustment. We are developing prosthetic fingers that imitate the appearance, mechanical properties and sensory capabilities of human fingers, and integrating them with prosthetic and robotic hands.
