Interactive forces caused by scanning wavy surfaces

Well-designed force fields can cause the perception of surface shapes such as holes or bumps on a flat surface without involving actual geometric displacements during exploratory hand motions. To establish a better force field model, we observed the interactive forces caused by scanning a sinusoidal wavy surface under point and surface contact conditions. Under the point contact condition, the acquired forces fit well into the model of earlier studies with the exception of kinetic frictions. When the surface was scanned with a bare finger to obtain a surface contact area, the observed force profiles significantly deformed compared with those of the earlier static point-contact model. Such deformation of the force profile can be explained by combining Hertz contact theory and the static point-contact model. The results of this study will lead to the development of an interactive force model for surface exploration, that is expected to improve force rendering algorithms.