Coordinate Frames in Robotic Teleoperation

Abstract

Abstract-An important mode of human-robot interaction is teleoperation, in which a human operator directly controls a robot via hardware such as a joystick or mouse. Such control is not always easy, however, as the viewpoint of the human, the alignment of the input device, and the local coordinate frame of the robot are rarely all aligned. These discrepancies force the user to reconcile the involved coordinate frames during teleoperation. Therefore, the choice of coordinate frames is critical since an unintuitive coordinate frame mapping will likely lead to higher mental workload and reduced efficiency. We discuss this concern, describe the various difficulties involved with natural remote teleoperation of a robot, and report experiments that demonstrate the effects of using different frames of reference on task performance and user mental workload.

A Design Space of Control Coordinate Systems in Telemanipulation

“…We used Tukey's HSD test to make pairwise comparisons. We found high inter-subject variability in our results, which matches prior studies that compare control coordinate systems [4], [5].…”

“…To control a robot manipulator's end-effector with a spatial input device, telemanipulation systems need to map user inputs to some control coordinate system in the remote environment. The control coordinate systems in prior works fall into a few patterns, including a coordinate frame attached to the base of the robot [4]- [7], the camera [4], [5], [8], or the end-effector [4], [5], [9]- [11]. While specific choices made by individual systems have been described in prior works, this paper provides a design space for designers to understand the range of possible control coordinate systems and reason about their suitability.…”

“…Camera frame [4], [18], [42] Camera right Camera forward Camera up End-effector frame [4], [41], [42] End-effector x-axis End-effector y-axis End-effector z-axis Orbit control -Fig. 2A [34] End-effector right (in a spherical coordinate system)…”

Manually Acquiring Targets From Multiple Viewpoints Using Video Feedback

“…While extensive work has gone into minimizing such perceptual-motor misalignments in teleoperation and robotic surgery, similar questions remain regarding camera pose selection when performing manual tasks with visual assistance in other settings. Teleoperation affords the ability to realign control frame of reference with the visual display, but it is not possible to computationally realign hand and arm movements with visual viewpoints because the monitor and the controller are decoupled (Hiatt & Simmons, 2006). Thus, the operator must perform perceptual-motor adaptations to reconcile movements displayed in conjunction with their body orientation (Cunningham, 1989).…”