Force Discrimination Ability of the Human Hand near Absolute Threshold for the Design of Force Feedback Systems in Teleoperations

Abstract

Force discrimination ability is an important surgical skill for micro or minimally invasive surgeries. This article analyzes the force perception of the human hand for lowintensity stimuli. Psychophysical experiments were conducted to measure just noticeable differences (JNDs) at four reference forces below 1 N. Reference forces are chosen to be in the range of forces in minimally invasive surgery that do not follow Weber's law. The force discrimination ability of two groups of subjects, surgeons and non-surgeons, is compared. Results demonstrate a superior ability of surgeons in discriminating small forces. The relationship between the JND and stimulus near absolute threshold is modeled. The application of the model in the design of force feedback systems for surgical teleoperation is discussed. In a force augmenting teleoperation system, the force feedback signal is amplified based on the characteristics of the human perception system. Therefore, the degraded human sense of touch at low-intensity forces would be compensated.