A Haptic Shared Autonomy With Partial Orientation Regulation for DoF Deficiency in Remote Side.

Orientation regulation permits an autonomous controller to regulate the operators' orientation commands automatically. Although kinds of orientation regulation strategies have been proposed for various purposes, few works have focused on the partial orientation regulation (POR), which requires an autonomous controller to prevent the unreachable rotational motion for safety, while preserving the remaining motions for intuitiveness. However, the POR is deeply demanded for systems with Degree-of-Freedom (DoF) deficiency in remote side. The POR is a more challenging task owing to: First, it is difficult to decompose an orientation into reachable and unreachable components due to the non-linear structure of the rotation group SO(3). Second, it is non-trivial to design a haptic rendering algorithm which can indicate the missing DoF information to human operators. To address the rotational DoF deficiency, we propose a haptic shared autonomy with POR ability, based on the perpendicular curve theory in SO(3). The proposed method can partially regulate the operator's orientation command to discard the unreachable motions and preserve the remaining motions for follower robots. Here the conventional "master" and "slave" are all replaced by "leader" and "follower" to avoid the concern of association to racism and human subjugation. In addition, a haptic rendering algorithm is designed to display correct haptic cues about the missing DoF to operators. The simulation and experimental results validate the effectiveness of the proposed method.