Comprehending finger flexor tendon pulley system using a computational analysis
This work addresses the need for improved prosthetic/orthotic and surgical designs by providing insights into biological finger mechanics, though it is incremental as it builds on existing computational models.
The study tackled the problem of designing prosthetic/orthotic devices by analyzing the tendon-pulley system (TPS) in biological fingers to identify configurations that minimize tendon tension, bowstringing, and pulley stresses, resulting in recommendations for optimal TPS setups based on computational simulations.
Existing prosthetic/orthotic designs are rarely based on kinetostatics of a biological finger, especially its tendon-pulley system (TPS) which helps render a set of extraordinary functionalities. Studies on computational models or cadaver experiments do exist. However, they provide little information on TPS configurations that lead to lower tendon tension, bowstringing, and pulley stresses, all of which a biological finger may be employing after all. A priori knowledge of such configurations and associated trade-offs is helpful not only from the design viewpoint of, say, an exoskeleton but also for surgical reconstruction procedures. We present a parametric study to determine optimal TPS configurations for the flexor mechanism. A compliant, flexure-based computational model is developed and simulated using the pseudo rigid body method, with various combinations of pulley/tendon attachment point locations, pulley heights, and widths. Deductions are drawn from the data collected to recommend the most suitable configuration. Many aspects of the biological TPS configuration are explained through the presented analysis. We reckon that the analytical approach herein will be useful in arriving at customized (optimized) hand exoskeletal designs.