Whisker-based Active Tactile Perception for Contour Reconstruction

TL;DR

This paper introduces an active tactile perception system using a magnetically transduced whisker sensor and control policy to accurately reconstruct object contours, demonstrating effectiveness in simulations and real-world tests.

Contribution

It presents a novel active control method for whisker-based tactile sensing, including a new sensor design, tip contact extraction, and surface contour reconstruction techniques.

Findings

Effective contour reconstruction with sub-millimeter accuracy.

Successful real-world and simulation validation.

Robust active control maintaining optimal contact pose.

Abstract

Perception using whisker-inspired tactile sensors currently faces a major challenge: the lack of active control in robots based on direct contact information from the whisker. To accurately reconstruct object contours, it is crucial for the whisker sensor to continuously follow and maintain an appropriate relative touch pose on the surface. This is especially important for localization based on tip contact, which has a low tolerance for sharp surfaces and must avoid slipping into tangential contact. In this paper, we first construct a magnetically transduced whisker sensor featuring a compact and robust suspension system composed of three flexible spiral arms. We develop a method that leverages a characterized whisker deflection profile to directly extract the tip contact position using gradient descent, with a Bayesian filter applied to reduce fluctuations. We then propose an active motion control policy to maintain the optimal relative pose of the whisker sensor against the object surface. A B-Spline curve is employed to predict the local surface curvature and determine the sensor orientation. Results demonstrate that our algorithm can effectively track objects and reconstruct contours with sub-millimeter accuracy. Finally, we validate the method in simulations and real-world experiments where a robot arm drives the whisker sensor to follow the surfaces of three different objects.