Perception and Control of Finger Forces

Abstract

Abstract The focus of this research is on the perception and control of forces produced by the hand. It is known that the change in force that subjects can reliably discriminate is approximately 6%, and that subjects are able to match forces generated by two corresponding muscle groups with an accuracy of approximately 15%. The present study was concerned with measuring the ability to control finger force using only haptic feedback and both haptic and visual feedback. It was found that subjects were surprising good at controlling forces for up to 120 s using only haptic feedback with mean absolute errors of less than 0.3 N over a force range of 2–6 N. The variation in force averaged 10.5% when haptic feedback was available and decreased to 6% when visual feedback was also provided. These results provide a framework for specifying the characteristics of force-reflecting haptic interfaces that should optimize human perception.