Visiflex: A Low-Cost Compliant Tactile Fingertip for Force, Torque, and Contact Sensing

We present the Visiflex, an inexpensive compliant tactile fingertip capable of contact localization and 6 degree-of-freedom (dof) contact force and torque measurement. Because manipulation of rigid or nearly-rigid objects requires compliance at the contact, we build compliance directly into the Visiflex in the form of a well-characterized 6-dof flexure between the fingertip and the base of the Visiflex. This compliance also allows the use of a 6-dof position sensor to measure forces and torques transmitted through the fingertip. The position sensor is a camera, and the same camera is used to detect contact locations on the fingertip via frustrated total internal reflection (FTIR). Our tests indicate that typical errors in contact location detection are less than 1 mm and typical errors in force sensing are less than 0.3 N. A video of the Visiflex can be found online.