Second-Order Information Recovery in Oriented-Plane Curvature Reproduction

Oriented-plane curvature reproduction, the control of fingertip deformation by orientating a flat plate on contact points to generate a sensation of curvature, is one of the curvature reproduction methods with favorable effects. However, among the three geometric cues of curvature, only the zeroth- and first-order information is recovered with this method, whereas the second-order information (i.e., local curvature) is neglected due to the oriented plate's inherent characteristic of having a planar surface. The second-order information will change the contact length between the finger and the surface and thus affects the feeling. As a solution for this problem, this paper proposes to control the indentation depth of the finger pulp on the oriented plate such that the correct contact length is reproduced during the rendering. A finger wearable device is developed to control that indentation depth. Three psychophysical experiments are carried out and the results indicate that the second-order information plays a positive role in curvature rendering.