Foot-operated tele-impedance control interface for robot manipulation tasks involving interaction with unstructured and unpredictable environments

Abstract

Tele-impedance can increase interaction perfor- mance between a robotic tool and unstructured/unpredictable environment during teleoperation. However, the existing tele- impedance interfaces have several ongoing issues, such as long calibration times and various obstructions for the human oper- ator. In addition, they are all designed to be controlled by the operator’s arms, which can cause difficulties when both arms are used, as in bi-manual teleoperation. To resolve these issues, we designed novel foot-based tele-impedance control method inspired by the human limb stiffness ellipse modulation. The proposed mechanical interface is based around a circular disc and a foot pressure sensor that controls orientation and size/shape of the stiffness ellipsoid, respectively, by the operator’s foot. We evalu- ated the circular disc interface control method in an experimental study with 12 participants, who performed a two-dimensional drilling task in a virtual environment. The results show the ability of the operator in controlling the proposed interface to dynamically adapt to task instruction and environment. In addition, a comparison with low and high constant impedance control demonstrate a superior interaction performance of the proposed interface.