Weight and friction display device by controlling the slip condition of a fingertip

In this paper, we propose a novel haptic device that gives weight and friction illusions. Sensing a slip condition at a fingertip plays an important role to estimate the weight and friction properties of an object. This fact suggests that controlling the contact condition could yield weight and friction illusions. Based on this idea, a prototype device was developed that controls the contact surface between a fingertip and a rigid plate based on a camera-based eccentricity control. The desired eccentricity profile was given from the mathematical relationship between the eccentricity and the surface deformation, which is obtained by known material parameters, vertical/lateral forces applied on the contact area, and static friction coefficient. The performance of the developed device was evaluated through human experiments. The experimental results show the statistically significant difference between presented weight and friction conditions.