Measurement of Grasp Position by Humans for Soft-Fingered Robotic Hands

In this study, we investigate how humans decide the grasping position for contacting objects of various sizes and shapes using two fingers. We propose a grasp criterion that yields the best grasping position for a two soft-fingered robotic hands. The relationship between the grasp direction/angle and the grasping position in a situation where a vertex object is grasped is analyzed numerically by minimizing a proposed performance function. Results show that many observed grasping positions used by humans correspond to a set of weighting coefficients that equally weigh all the factors in the criterion. We set up the hypothesis “The human might like grasping position in which the finger was not greatly intuitively expanded”. This is verified by the numerical optimization and experiments by ten subjects.