Craig Sayers

An operator interface for teleprogramming employing synthetic fixtures

In the teleprogramming system an operator is presented with a virtual reality representation of a remote environment. The operators interaction within that virtual environment is observed and translated into a sequence of robot program instructions for transmission to, and execution by, a robot at the remote site. In this paper we focus on operator interaction with the master station of the teleprogramming system. The use of synthetic fixtures to provide force and visual clues to assist the operator in performing tasks with speed and precision is discussed. It is suggested that, at least in some situations, it is both necessary and desirable to trade off realism for improved task performance. The difficulty of coping with exceptional conditions and, in particular, uncertainty in the world model used to generate the virtual environment is described and the operator interface for diagnosing and resolving errors is presented. An overview is also given of both the hardware and software used to implement the master station for the teleprogramming system.

Visual imagery for subsea teleprogramming

The objective of this work is to allow subsea teleoperative tasks to be performed efficiently even when all communication between human operator and remote robot is via an acoustic link. This paper describes the integration of remote site cameras into the teleprogramming system. Images from these cameras may be used for calibrating and maintaining the world model as well as for aiding the operator in diagnosing and recovering from unexpected events. The constrained communications channel forces the adoption of an intelligent approach to image transmission. The system automatically selects windowing and subsampling parameters while varying frame rates and task execution speeds to match that which the system can support given available bandwidth and computational constraints. Examples are presented from tests in which an operator in Philadelphia controlled a robot manipulator mounted on an underwater vehicle submerged off the Massachusetts coast.

Time Delay Insensitive Teleoperation

The properties of the communications link between the operator and slave manipulator have always been a limiting factor in teleoperation systems. This paper describes the teleprogramming concept which overcomes the effects of both limited bandwidth channels and delayed coriiniunications by transmitting not Cartesian, or joint level information, but rather symbolic, error-tolerant, command program segments to the remote site. The operator interacts with a geometric graphical model of the remote site which provides inimediate visual and kinesthetic feedback. Command programs are automatically generated by the master system as it monitors the operator’s actions. The slave site executes the received program, stepby-step, delayed with respect to the master, until an error condition is detected whereupon it notifies the master and awaits new commands. In this system the operator/task interaction rate is dominated by the mean time between errors and riot the speed of the communications link. The teleprograinming system has been demonstrated using a simple exploratory task and is being extended to the more complex case where tools are used a t the remote site. The ability of teleprogramming to cope with delays on the order of seconds makes it well suited to both subsea and outer space applications. Some advantages may also be realized by applying a similar paradigm to cases where the delay is significantly shorter or longer.

Teleprogramming to perform sophisticated underwater manipulative tasks using acoustic communications

In this paper we describe preliminary in-air testing of the teleprogramming system. By way of example we describe the task of bolting/unbolting a hatch cover. The position of the cover was known only approximately and all communication between the operator and remote sites occurred via a simulated acoustic link. No visual feedback from the remote site was available. The operator interaction required to command the remote robot for this task is discussed and the mechanism for detecting, diagnosing and recovering from errors is presented. It is observed that, while operators may successfully complete this task, it takes too long to recover from errors. Current research is aimed at improving performance by providing additional visual information to the operator and migrating this test system to a real subsea implementation.<<ETX>>

Operator Control of Robotic Systems

A characteristic feature of teleoperation is that, given time, tasks are generally successfully completed. This is caused not so much by careful engineering as it is by the continuous presence of an intelligent human operator. We are interested in developing systems which are similarly as effective in performing tasks while operating under constrained communications channels or controlling multiple robotic agents. To handle the problem of constrained communications channels we have developed the teleprogramming paradigm which uses local high-bandwidth feedback at the operator and remote sites while employing relatively low-bandwidth communication between sites. To deal with multiple robotic agents a multi-level approach is required. To this end we are developing the MASC (Multiple Agent Supervisory Control) system which provides the human operator with tools to interact with all processing levels of a robotic system. In developing these implementations, the emphasis has moved from developing systems which are correct to systems which may be corrected. While the former has proven an elusive goal in robotics, the latter is well within the domain of software engineering. Our intention is not to develop hardware/software which is optimal for a particular task. Rather, the goal is to demonstrate that our approach permits successful task performance even while using imperfect equipment in a very imperfect world.

Integrating an Operator with a Robotic System

Abstract In autonomous robotic systems there is a temporal separation between the operator/programmers interaction with the system and subsequent task execution. While in conventional teleoperation systems the separation between the operator and the remote task is spacial with no significant time delay. This paper considers the case of the teleprogramming system where the operator is separated both spacially and temporally from the remote manipulator. The operator interaction with the teleprogramming system is drawn from teleoperation while the task execution is drawn from robotics. The failure of robotic systems to handle real-world interaction is overcome by the presence of an intelligent operator.

Interacting with Uncertainty

This paper considers issues related to the design of a system which can aid the operator in their interaction with the uncertain real world. This takes several complimentary approaches. The first is to reduce discrepancies between the master stations initial, imprecise, model of the slave site and the real remote world. This may be achieved by utilizing information received from the slave manipulators kinesthetic interaction with the environment. The second is to make the operator aware of uncertainty by using color clues in the graphical user interface to provide an indication of uncertainty--this should allow an operator to compromise between speed and accuracy. The final approach is to reduce uncertainty in the position of the master arm by actively guiding it along one, or more, degrees of freedom such that it conforms to pre-defined and task-dependent geometric primitives.