Three-dimensional contact imaging with an actuated whisker

Contact sensors cab provide high-information-density object surface sensing in harsh and/or opaque environments. This paper describes the design, modeling, control, and data processing of a contact imager consisting of a flexible whisker mounted on a two-axis robot through a load cell. The whisker sweeps around and into contact with unknown objects, determining the three-dimensional location of contact points to within a specified position resolution. During contact, the whisker bends along the surface normal, producing large deflections. The joint angles and load cell signals are numerically-processed to determine the whisker shapes. Comparison of whisker shapes during bending determines contact point location. Experimental results for several objects with wide ranging surface curvature and roughness demonstrate 1.51-cm resolution for a 45.5-cm whisker.