Speaker: Francisco Valero-Cuevas (Cornell University)

Title: Identifying the functional mechanism by which biological hands meet the necessary and sufficient physical requirements for dexterous manipulation.


Abstract:
The mechanical versatility and functionality of organisms continually challenge and inspire engineers to create machines with such capabilities. In spite of these efforts, what we loosely call "dexterous manipulation" remains a premier example of how the functional capabilities of complex machines lag far behind those of their biological counterparts. In our work to approach this challenge, we consider machines and organisms as part of a same continuum of solutions to the problem of interacting with the physical world. The differences between machines and organisms are, then, only incidental to the availability of materials, sensors, actuators, and information processing capabilities.

Based on this perspective, our work towards understanding, restoring and improving dexterous manipulation in humans and robots can be described as an inversion of biomimetism. Instead of creating machines to emulate salient features of organismal function, we use the theoretical and analytical framework developed by mathematicians and engineers to identify the functional mechanism by which biological hands meet the necessary and sufficient physical requirements for dexterous manipulation. In this way we can begin to tease apart the contributions of passive structures (skin, bones, tendons), actuators (muscles), sensors (proproiceptors) and controllers (spinal and cortical neural systems), to uncover the mechanistic basis for the emergent behavior we call dexterous manipulation. Our integrative research activities emphasize an unambiguous mechanical definition of hand function, insistence on anatomical detail, and meticulous characterization of brain and muscle activity. Some of our findings include that (i) the coordination of redundant muscles is at times driven by optimization of mechanical requirements; (ii) driving the fingers to some limit of sensorimotor performance is instrumental to elucidating and evaluating motor control strategies; and (iii) the complex anatomy of finger tendons can be explained by the need to produce force in every direction.

Identifying the contribution of passive and active components of the brain-hand system has tremendous potential to illuminate, for example, (i) how disease and treatment affect manipulation, (ii) how to reanimate paralyzed limbs and control robotic prosthesis, and (iii) how to develop dexterous robotic hands.