Robust finger gaits from closed-loop controllers

Abstract

Object manipulation using multi-fingered dextrous robot hands poses formidable control challenges due to the complexity of the manipulator, its workspace limitations. To address large-scale manipulation tasks, finger gaits are often used to reposition fingers. In this paper, an approach to finger gaiting is presented which constructs behavior on-line by activating combinations of reusable feedback control laws with formal stability and convergence properties drawn from a control basis. Finger gaits are constructed as finite state control strategies in a DEDS framework, while actual contact locations and object motions are computed reactively based on local contact information. This leads to manipulation strategies that are robust with respect to a limited range of perturbations, object geometries, and manipulator kinematics. To demonstrate this, two finger gaits are constructed and applied to different object geometries and robot hands.