Scaling and Eliminating Non-Contact Forces and Torques to Improve Haptic Feedback Teleoperation

In haptic-feedback teleoperation, the operator experiences forces and torques applied to the slave manipulator. These forces, however, consist of two components: on the one hand, forces and torques due to environmental contact, and on the other hand, non-contact forces, i.e., inertial forces, centrifugal forces, Coriolis forces, and associated torques. For several reasons, eliminating these non-contact forces and torques from the force-torque measurements of the slave or scaling them may prove beneficial. For instance, in highly-dynamic teleoperation tasks, these forces and torques may contribute to operator fatigue or hamper the detection of environmental contacts. This paper briefly reviews how the inertial parameters of the slave load, e.g., an end-effector or a gripper, can be estimated. Subsequently, a method for eliminating the non-contact forces and torques from the measurements of a wrist-mounted forcetorque sensor or scaling them is presented. After a brief overview of our teleoperation system, experimental results are presented which demonstrate the effectiveness of our approach.