Determining the threshold of time-delay for teleoperation accuracy and efficiency in relation to telesurgery.

BACKGROUND: Advances in robotics have made teleoperated surgical procedures a feasible means of treating patients in remote locations. In this study a suite of experiments was performed to investigate the influence of time-delay on teleoperation accuracy and efficiency during a path-following task. MATERIALS AND METHODS: Subjects used a Phantom Omni 6-degrees of freedom (dof) input device (Sensable, Triangle Park, NC) to move the end-effector of a Mitsubishi (Tokyo, Japan) PA-10 7-dof robotic manipulator along a prescribed path. End-effector motion was recorded using a video motion capture system. Time-delays ranging from 0 to 2.5 s were artificially imposed. Performance was quantified by time to complete the task, path length, and square root-mean-square (RMS) error. Randomization of time-delay order and allowance for practice runs reduced the learning effect. An imposed time limit and pacing were used to negate the move-and-pause strategy that emerged in early trials. RESULTS: Time to complete the task and RMS error generally increased with increasing time-delay. Path length also generally increased, but not as consistently. With imposed pacing, RMS error continued to increase beyond 1.5 s, and some subjects were not able to complete the task in the allotted 90 s. CONCLUSIONS: The results suggest a threshold of time-delay in the range of 1.5-2.0 s. Beyond 1.5 s, subjects adopted a move-and-pause strategy that increased completion time to preserve path-tracking accuracy. If paced, tracking accuracy tended to degrade substantially beyond 1.5 s. A strong learning effect was evident, and experienced teleoperators performed substantially better than novices.

Evaluation of teleoperated surgical robots in an enclosed undersea environment.

The ability to support surgical care in an extreme environment is a significant issue for both military medicine and space medicine. Telemanipulation systems, those that can be remotely operated from a distant site, have been used extensively by the National Aeronautics and Space Administration (NASA) for a number of years. These systems, often called telerobots, have successfully been applied to surgical interventions. A further extension is to operate these robotic systems over data communication networks where robotic slave and master are separated by a great distance. NASA utilizes the National Oceanographic and Atmospheric Administration (NOAA) Aquarius underwater habitat as an analog environment for research and technology evaluation missions, known as NASA Extreme Environment Mission Operations (NEEMO). Three NEEMO missions have provided an opportunity to evaluate teleoperated surgical robotics by astronauts and surgeons. Three robotic systems were deployed to the habitat for evaluation during NEEMO 7, 9, and 12. These systems were linked via a telecommunications link to various sites for remote manipulation. Researchers in the habitat conducted a variety of tests to evaluate performance and applicability in extreme environments. Over three different NEEMO missions, components of the Automated Endoscopic System for Optimal Positioning (AESOP), the M7 Surgical System, and the RAVEN were deployed and evaluated. A number of factors were evaluated, including communication latency and semiautonomous functions. The M7 was modified to permit a remote surgeon the ability to insert a needle into simulated tissue with ultrasound guidance, resulting in the world's first semi-autonomous supervisory-controlled medical task. The deployment and operation of teleoperated surgical systems and semi-autonomous, supervisory-controlled tasks were successfully conducted.

Plugfest 2009: Global Interoperability in Telerobotics and Telemedicine.

Despite the great diversity of teleoperator designs and applications, their underlying control systems have many similarities. These similarities can be exploited to enable inter-operability between heterogeneous systems. We have developed a network data specification, the Interoperable Telerobotics Protocol, that can be used for Internet based control of a wide range of teleoperators. In this work we test interoperable telerobotics on the global Internet, focusing on the telesurgery application domain. Fourteen globally dispersed telerobotic master and slave systems were connected in thirty trials in one twenty four hour period. Users performed common manipulation tasks to demonstrate effective master-slave operation. With twenty eight (93%) successful, unique connections the results show a high potential for standardizing telerobotic operation. Furthermore, new paradigms for telesurgical operation and training are presented, including a networked surgery trainer and upper-limb exoskeleton control of micro-manipulators.