A promising way to achieve increased remote worksystem efficiency is to layer telerobotic technologies onto teleoperated remote systems. The research being reported here will enable the teleoperation baseline to be supplemented with operator-selective telerobotic modes of operation that allow automatic performance of subtasks that are either repetitive, require high precision, or involve extreme patience. Before subtask automation can be exploited, however, it is necessary to explicitly represent the 3D geometry of the task space scene surrounding the remote worksystem. The Robot Task Space Analyzer (RSTA) is a tool for remote equipment operators that combines infrared laser and visible stereo imaging, human-interactive modeling and computer-based object recognition to build 3D models of the immediate work zone in which a robot system is operating. This paper presents the hardware and software design of the RTSA system. Human factors aspects the system operation and design are discussed.

Waste tank cleanup is a current application area for robotics in the United States. As a result of tank access restrictions, designs for several current waste cleanup manipulator systems have long links with small cross-sections and variable lengths. In addition, as a result of anticipated payload capacity, these manipulator designs are hydraulically actuated. This paper takes two approaches to investigating the problem of the control of manipulators having variable-length flexible links and hydraulic actuators. First, a simulation of a hydraulically actuated, 2-DOF, polar (r-/spl Theta/), manipulator with one flexible link is used to illustrate the problem of applying controllers successfully developed for hydraulically actuated, fixed-length flexible manipulators to hydraulically-actuated, variable-length systems. Next, based upon the simulation results, simple controller modifications are proposed and are shown to work on a full-scale experimental test bed. Motion control of hydraulically actuated, variable-length flexible-link manipulators is the focus of this paper.

The primary mission of Oak Ridge National Laboratory (ORNL) during World War II was the processing of pure plutonium metal in support of the Manhattan Project. Between 1943 and 1951, the Gunite and Associated Tanks (GAAT) at ORNL were built to collect, neutralize, and store the radioactive by-products. Currently, twelve gunite tanks and four stainless steel tanks are located on the ORNL complex. These tanks hold approximately 75,000 gal of radioactive sludge and solids and over 350,000 gal of liquid. Characterization studies of these tanks in 1994 indicated that the structural integrity of some of the tanks is questionable. Subsequently, there is presently an aggressive program directed towards the remediation and relocation of waste stored in the ORNL tanks. A number of factors complicate the remediation process. The material stored in these tanks ranges from liquid to sludge and solid and is composed of organic materials heavy metals, and radionuclides. The tanks, which range from 12 to 50 ft in diameter, are located below ground and in the middle of the ORNL complex. The only access to these ranks is through one of three access ports that are either 12 or 24 in. in diameter. These characteristics provide a daunting challenge: How can material be safely removed from such a confined structure? This paper describes the existing strategy and hardware presently used in the remediation process. This is followed by a description of an integrated hardware system model. This investigation has isolated a few key areas where further work is needed.

Most of the research related to flexible link manipulators to date has focused on single link, fixed length, single plane of vibration test beds. In addition, actuation has been predominantly based upon electromagnetic motors. Ironically, these elements are rarely found in the existing industrial long reach systems. This paper describes a new hydraulically actuated, long reach manipulator with a flexible prismatic link at Oak Ridge National Laboratory (ORNL). Focus is directed towards both modeling and control of hydraulic actuators as well as flexible links that have variable natural frequencies.

Addresses two issues associated with the implementation of a hydraulically powered dissimilar master-slave teleoperated system. These issues are the overall system control architecture and the design of robust hydraulic servo controllers for the position control problem. Finally, a discussion of overall system performance on an actual teleoperated system is presented. (Schilling's Titan II hydraulic manipulators are the slave manipulators and the master manipulators are from the Oak Ridge National Laboratory-developed Advanced Servo Manipulator).

The remediation of single-shell radioactive waste storage tanks is one of the urgent tasks of the Department of Energy that challenge state-of-the-art equipment and methods. The use of long-reach manipulators is being seriously considered for this remediation task. Because of high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to use hydraulic actuators and to exhibit significant structural flexibility. The controller has been designed to compensate for the hydraulic actuator dynamics by using a load-compensated velocity feedforward loop and to increase the bandwidth by using a pressure feedback loop. Shaping filter techniques have been applied as a feedforward controller to avoid structural vibrations during operation. Among various types of shaping filter methods investigated an approach, referred to as a "feedforward simulation filter" that uses embedded simulation, has been presented.

This paper highlights a ranging sensor that can be calibrated at standoffs of 1 to 3 feet with a depth of field of /spl ap/1 ft. Tests at a 16" standoff have produced a 0.004 inch standard deviation in height measurement errors. The data density and field of view are programmable. The sensor is positioned robotically, allowing it to provide accurate, shed-range measurements prior to manipulation tasks. The sensor head is relatively inexpensive (/spl ap/$10 k) and is designed for in situ calibration. This approach is intended to allow replacement components to be installed, calibrated, and validated without decontamination. Calibration, validation and data acquisition are all designed to be performed remotely and in a highly automated fashion. These in situ features of the design are targeted for the interest of industry with the aim of producing a sensor having a longer lifetime and a lower maintenance cost.

A method to simultaneously optimize multiple performance criteria for a redundant manipulator is presented. Preferred formulation requirements for the criteria are discussed, and previously proposed normalization methods are examined. A statistically based variable weighting technique is developed and evaluated. A seven-degree-of freedom Robotics Research Corporation manipulator is used as a test bed for the multiple criteria optimization scheme.>

Ways a stiffness controller can be used to control a teleoperator system with a redundant degree-of-freedom (DOF) slave manipulator and a dissimilar master are examined. No path planning is allowed because of the uncertainty of the environment and computational limitations. The proposed controller was implemented on the 7-DOF Center for Engineering Systems Advanced Research Manipulator slave manipulator with a 6-DOF Kraft master manipulator. The overall performance of this scheme and future directions are discussed.>