Wire arc additive manufacturing is a metal additive manufacturing process in which the material is deposited using arc welding technology. It is gaining popularity due to high material deposition rates and faster build time. It is en-abled using robotic manipulators and can build relatively large-scale parts faster when compared with other metal additive manufacturing processes. However, the size of the large-scale parts is limited by the size of the industrial manipulator being used for the process. This limitation is overcome by using a fixed configuration multi-robot cell in which manipulators work cooperatively to build large-scale parts quickly. A fixed multi-robot cell with closely spaced industrial manipulators has high flexibility, but it restricts the part size that can be built. If the manipulators are spread out, the cell loses its flexibility but can build relatively larger parts. This issue can be avoided by using larger size manipulators, which are expensive, or by moving the modest size manipulators based on the part geometries. This paper presents a novel algorithm to generate multi-robot placements for different part geometries to be built using wire arc additive manufacturing. Furthermore, the algorithm hierarchically optimizes the build time and the inverse kinematics consistency in robot paths to improve the process efficiency and part quality. We compare the results with fixed multi-robot cells and provide insights to users to make an informed decision on whether to use a fixed or a flexible multi-robot cell for wire arc additive manufacturing.

A new class of fluoroscopy, using a robotic mobile platform, is being developed. The Tracking Fluoroscope System (TFS) is intended to be an orthopedic diagnostic tool that provides more accurate and detailed in vivo pre-operative and post-operative information for surgeons. This is accomplished through the ability to fluoroscope natural and uninterrupted human joint motion during level walking, step climbing, and ramp walking. This overall functionality requires independent tracking of the position and orientation of the body with respect to the robotic platform, as well as the position of the joints with respect to the body. The overall robotic system, embodied in the TFS, necessary to accurately perform real-time imaging of joints in motion is discussed. Recent subject and joint tracking experimental results are presented.

Large multi-fingered end-effectors have promise to provide the added dexterity needed for manipulation while decreasing the amount of special fixturing required for tooling and object manipulation common to remote handling operations in hazardous and unstructured environments such as those in the nuclear domain. This paper presents the integration of a heavy-duty three-fingered articulated hand with a Schilling Titan hydraulic manipulator that is part of a comprehensive telerobotics test bed. Experiments demonstrated that a multi-fingered end effector approach has distinct benefits and advantages.

This paper discusses the tracking algorithms and approach used to control the tracking fluoroscope system. It is a mobile platform equipped with an on-board fluoroscope system to perform real-time imaging of human joints in motion: ankles, knees and hips. In order to record the natural and uninterrupted joint motion, the person has to be able to walk freely while being followed by the robot. It requires independent tracking of the position and orientation of the body with respect to the platform as well as joint positions with respect to the trunk of the body. This paper investigates the problem of tracking position and orientation of a walking person with respect to the following robotic platform.

Sensors such as cameras and range finders provide flexibility and safety to telerobotic manipulations. However, in order to use their supportive features, sensor-based telerobotic control requires that both the sensors and the robot arm be calibrated so that the manipulator can target and articulate objects in the environment easily and effectively. The scope of this paper is to define the sensor-manipulator calibration issue, outline the system errors, describe the calibration methods, and explain the algorithms necessary to provide compensation. The problem was divided into three steps: acquisition of calibration data of the sensor and the arm, numerical analysis and determination of needed parameters, and validation of obtained results. Since the task is to find parameters that represent the object position accurately, the problem is treated as multidimensional least squares optimization problem with simple bounds. The function to minimize is the distance between the target and its calculated position. Two approaches are applied to represent kinematics parameters: Euler angles and quaternions. Solutions are analyzed to determine the best method for future planned online calibration checks as well as to perform teleoperation tasks on the calibrated system