Acquisition of Contact Force and Slippage Using a Vision-Based Tactile Sensor with a Fluid-Type Touchpad for the Dexterous Handling of Robots

This paper presents a new approach for estimating contact force and slippage by using a vision-based tactile sensor with a fluid-type touchpad for the dexterous handling of robots. The sensor consists of a CCD camera, LED lights, a transparent acrylic plate and a deformable touchpad. The sensor can obtain a variety of tactile information, such as the contact force, shape, contact region, position and orientation of an object in contact with the fluid-type touchpad. The previous method for measuring contact force requires extensive calculation; this paper proposes a new method based on lookup tables for measuring normal force, tangential force and moment, using a fluid-type touchpad. Additionally, we clarify the mechanism of slippage between a fluid-type touchpad and a contacted object. This mechanism is efficient for applying the proposed slippage estimation method to a fluid-type touchpad. The validation of the proposed methods is confirmed in the experimental results.