Effect Of The Tangential Forces In Contact Interface Of Soft Finger For Grasping an‎d Manipulation

Different models have been investigated for the pressures distribution in the contact interface of a soft finger and an object through the previous studies. Such models have been suggested with no regarding for the influence of the tangential forces that being commonly affected in the contact interface of a soft finger and an object during the grasping and manipulation. Possessing a precise distribution model of pressures through the contact interface is important to develop the friction limit surface (FLS) modeling and design the tactile sensors. In the present research, a newly and highly precise model has been introduced for depicting the pressure distribution asymmetry in the contact interface of hemicylindrical soft fingertip beneath the tangential force and normal force. Such model has been derived depending on the observations in the preceding literature mentioning that the contact interface is moving and skewing to the tangential force direction. Depending on the suggested distribution model of pressure in the current investigation, an enhanced and a highly accurate FLS was introduced. The obtained profile of the FLS via such model was compared with matching outcomes depending upon preceding models. The fresh outcomes displayed that the asymmetry or skewness regard in pressure distribution (owing to the tangential force) leads the profile of the FLS to shrink in comparison with that built with the assumption of the symmetric distribution of pressure. That shrinkage, as a consequence of the asymmetry and skewness of the distribution of pressure, makes the contact interface highly susceptible. Also, the normalized characteristic pitch was not affected by the tangential force. Additionally, such fresh model can also supply more accuracy in different areas, like designing the tactile sensors, haptic perception and enhancing the FLS modeling for the robotic as well as prosthetic hands.