Grip Force Control by Detecting the Internal Strain Distribution Inside the Elastic Finger Having Curved Surface

In this study we propose a method for controlling contact force when object is lifted by fingers having curved surface without producing whole slip or applying excessive force even when the weight and the friction coefficient of the object are unknown. The deformation of the elastic finger when the finger is in contact with the object with/without tangential load is calculated by using a FE (finite eloment) analysis. It is found that the partial incipient slip region at the contact surface changes due to the change of the tangential force. It is also found that the internal shear strain distribution is in relation with the partial incipient slip at the contact surface during the precision grip. From this, we can conclude that we can obtain the tangential force change from the shear strain distribution inside the elastic body.