Finger Coordination Under Artificial Changes in Finger Strength Feedback: A Study Using Analytical Inverse Optimization

ABSTRACT

A recently developed method of analytical inverse optimization (ANIO) was used to compute cost functions based on sets of experimental observations in 4-finger pressing tasks with accurate total force and moment production. In different series, feedback on total force and moment was provided using the index finger force at its value, doubled, or halved. Finger force data across different force–moment combinations formed a plane. This allowed reconstructing cost functions as 2nd-order polynomials with linear terms. Changes in the coefficients of the cost function across the 3 series allowed the authors to offer a biomechanical interpretation related to constraints on finger forces with different lever arms. ANIO allows the authors to describe preferred regions within the space of solutions for redundant tasks in terms of cost functions.

Keywords:

• ANIO approach
• finger
• force
• redundancy
• inverse optimization

ACKNOWLEDGMENTS

This research was supported in part by NIH grants AG-018751, NS-035032, and AR-048563. The authors are grateful to Dr. Alexander Terekhov for his help at different phases of this project. They are also grateful to the anonymous reviewer for suggesting us the example considered in the Discussion section.