John V. Draper

Workload, flow, and telepresence during teleoperation

There is much speculation about the relationships among workload, flow, telepresence, and performance during teleoperation, but few data that provide evidence concerning them. This paper presents results of an investigation conducted during completion of a pipe cutting task using a teleoperator at the Oak Ridge National Laboratory. The results show support for the hypothesis that telepresence is related to expenditure of attentional resources, and some support for the hypothesis that telepresence is related to flow. The discussion examines the results from an attentional resources perspective on teleoperation.

Speculations on the value of telepresence.

Synthetic environments (SE) feature computer-mediated interaction with an environment physically separate from the user. An SE allows human perceptual, cognitive, and psychomotor capabilities to be projected into distant, dangerous, or simulated environments. This article examines some aspects of application of immersive/telepresence interfaces and discusses how the new technology fits into a user-centered design approach to teleoperators and virtual environments. The central theme of an immersive/telepresence design approach is that the world may be displayed to a user as if that person were physically present in a computermediated world. However, the ability of SEs to re-create a computer-mediated world by using immersive displays does not annul the responsibility of designers to tailor interfaces to meet the task-dependant needs of users. Whether functioning in reality or a virtual reality, interfaces must satisfy user information requirements to optimize performance. It does not necessarily follow that the combination of immersive interfaces, strict reproduction of the remote world, and telepresence gives users the most efficient human-machine interface. Other aspects of human behavior, such as concentration and attentional resource allocation or situation awareness, which are not necessarily encompassed by the concept of telepresence, need to be considered in the interface design.

Effects of Visual Interface Design, and Control Mode and Latency on Performance, Telepresence and Workload in a Teleoperation Task

Human-machine interfaces that facilitate telepresence are speculated to improve performance with teleoperators. Unfortunately, there is little experimental evidence to substantiate a direct link between the two. Further, there are limited data available on technological and psychological factors that affect telepresence. The objective of the present study was to evaluate the influence of interface design configuration, and control mode and latency on teleoperation performance, telepresence, and workload in a pick-and-place task. It was conducted to enhance understanding of the concept of telepresence and promote future development of telepresence-based guidelines for teleoperator systems. An experiment was conducted in which subjects were required to control a telerobot in a simple pick-and-place task through a virtual reality (VR) interface with or without live-video feedback on the motion of the robot. Rotational or translational motion control of the robot was studied under four control latencies ranging from 0 to 4 seconds. Results demonstrated significant benefits of using VR in conjunction with video feedback to control the telerobot. Rotational control appeared to better meet user expectations of robot motion control than modes involving translations of joint positions. Performance with the VR interface without live video feedback appeared to be sensitive to control latency. Correlation analysis provided further evidence of a positive link between telepresence and performance.

Human factors in telemanipulation: perspectives from the Oak Ridge National Laboratory experience

Personnel at the Robotics and Process Systems Division (RPSD) of the Oak Ridge National Laboratory have extensive experience designing, building, and operating teleoperators for a variety of settings, including space, battlefields, nuclear fuel reprocessing plants, and hazardous waste retrieval. In the course of the last decade and a half, the RPSD designed, built, and operated 4 telemanipulators (M-2, ASM, LTM, CESAR arm) and operated another half dozen (M-8, Model 50, TOS SM-229, RM-10, PaR 5000, BilArm 83A). During this period, human factors professionals have been closely integrated with RPSD design teams, investigating telemanipulator feedback and feed forward, designing cockpits and control rooms, training users and designers, and helping to develop performance specifications for telemanipulators. This paper presents a brief review of this and other work, with an aim towards providing perspectives on some of the human factors aspects of telemanipulation.

End-Effector Velocity and Input Frequency Effects on Teleoperator Performance

End-effector velocity defines two types of servomanipulators: operator-paced systems and machine-paced systems. Input frequency limits below human bandwidth may also cause machine-pacing. Two experiments varied end-effector velocity limits (1.01 meters per second, 86.4 centimeters per second, and 76.2 centimeters per second) and input frequency limits (0.16 Hz, 0.32 Hz, 0.64 Hz, and 1.27 Hz). Multivariate analyses of variance found statistically significant input frequency limit effects in one experiment, and significant input frequency and velocity limit effects in the second experiment. Machine-pacing caused by input frequency occurred in the range hypothesized (between 0.32 Hz and 0.64 Hz). The critical velocity limit appeared to be lower than expected (between 76.2 cm and 86.4 cm per second). These results are valuable for future teleoperator designs.

Activity and Cooperation in a Multi-Person Teleoperator Cockpit

This experiment attempted to determine how members of a teleoperator crew use equipment and interact when performing remote maintenance tasks. The experiment used a modified process analysis technique to record how users performed two typical remote maintenance tasks. Five people participated in the experiment. They were paired into teams representing several experience levels. Participants completed the tasks while two television cameras recorded their actions on videotape. Observers later scored the videotapes using the process analysis chart. The percent of time each participant spent engaged in each activity was calculated, as was the percent of time the participants cooperated and co-acted in the cockpit. This information will be helpful in designing future teleoperator cockpits and other related control rooms.

Achievability for telerobotic systems

Methods are needed to improve the capabilities of autonomous robots to perform tasks that are difficult for contemporary robots, and to identify those tasks that robots cannot perform. Additionally, in the realm of remote handling, methods are needed to assess which tasks and/or subtasks are candidates for automation. We are developing a new approach to understanding the capability of autonomous robotic systems. This approach uses formalized methods for determining the achievability of tasks for robots, that is, the likelihood that an autonomous robot or telerobot can successfully complete a particular task. Any autonomous system may be represented in achievability space by the volume describing that system’s capabilities within the 3-axis space delineated by perception, cognition, and action. This volume may be thought of as a probability density with achievability decreasing as the distance from the centroid of the volume increases. Similarly, any task may be represented within achievability space. Howe...

Periodic components of hand acceleration/deceleration impulses during telemanipulation

Responsiveness is the ability of a telemanipulator to recreate user trajectories and impedance in time and space. For trajectory production, a key determinant of responsiveness is the ability of the system to accept user inputs, which are forces on the master handle generated by user hand acceleration/deceleration (a/d) impulses, and translate them into slave arm acceleration/deceleration. This paper presents observations of master controller a/d impulses during completion of a simple target acquisition task. Power spectral density functions calculated from hand controller a/d impulses were used to assess impulse waveform. The relative contributions of frequency intervals ranging up to 25 Hz for three spatially different versions of the task were used to determine which frequencies were most important. The highest relative power was observed in frequencies between 1 Hz and 6 Hz. The key frequencies related to task difficult were in the range from 2 Hz to 8 Hz. Differences were also observed from 9 Hz to 12 Hz. The results provide clues to the source of the performance inhibition.