Vision Based Tactile Sensor Using Transparent Elastic Fingertip for Dexterous Handling

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

“…Tangential force was measured in the previous method by the displacement of the central dot and the radius of the contact region, using the elastic touchpad [21]. Figure 5a shows the displacement of the central dot when an object is in contact with the touchpad.…”

“…The previous method in [21] regarded the elastic touchpad and a contacted flat object as an elastic spherical object and a rigid flat object, respectively. The contact region in this case is a circle.…”

“…The difficulty is that the mechanism of slippage in the case of a fluid-type touchpad differs significantly from that of an elastic touchpad. Moreover, the method for measuring contact force by using a fluid-type touchpad requires extensive calculation [25], while the elastic touchpad can measure the contact force rapidly with the use of look-up tables [21]. In consideration of applications requiring rapid sensor response, the methods using lookup tables are much more efficient.…”

“…Our proposed sensor satisfies the above requirements: simultaneous acquisition of various kinds of tactile information; simple structure; and a deformable surface for the sensor. This sensor measures normal force, tangential force and rotational moment based on preliminarily-constructed lookup tables, which relate the deformation of the elastic touchpad to force and moment [21]. This sensor can also estimate slippage between the touchpad and a contacted object [22].…”

“…We have proposed a vision-based tactile sensor that can sense multiple types of tactile information simultaneously [21,22].The sensor consists of a CCD camera, LED lights, a transparent acrylic plate and a transparent hemispherical elastic touchpad for contacting the object. Here, the touchpad is deformable and the structure of the sensor is simple.…”