Control of free-flying space robot manipulator systems

New control techniques for self contained, autonomous free flying space robots were developed and tested experimentally. Free flying robots are envisioned as a key element of any successful long term presence in space. These robots must be capable of performing the assembly, maintenance, and inspection, and repair tasks that currently require human extravehicular activity (EVA). A set of research projects were developed and carried out using lab models of satellite robots and a flexible manipulator. The second generation space robot models use air cushion vehicle (ACV) technology to simulate in 2-D the drag free, zero g conditions of space. The current work is divided into 5 major projects: Global Navigation and Control of a Free Floating Robot, Cooperative Manipulation from a Free Flying Robot, Multiple Robot Cooperation, Thrusterless Robotic Locomotion, and Dynamic Payload Manipulation. These projects are examined in detail

State Regulatory Approaches to VoIP: Policy, Implementation, and Outcome

This Article explores the many perspectives on Voice over Internet Protocol ( VoIP ). The notion of the Article is not to resolve the definitive approach to VolP. Rather, this Article suggests that the process of the approach has itself become muddled. Individuals quibble, contrasting the superiority of one perspective over another, negating the reason why they were looking in the first place. This Article is the second part of a project to survey and analyze state VoIP policy. The first part of the project surveyed state VolP regulatory activity. This part seeks to place that precedent in a centrifuge, segregating out different groupings of precedent to determine whether patterns or lessons might emerge

The Legacy of the Federal Communications Commission’s Computer Inquiries

The FCC and the computer industry have learned much in the 35 years since the agency first began to regulate computer networks. Safeguards were imposed on common carriers for the benefit of the networks. This Article examines the so-called Computer Inquiries and how they have repeatedly re-examined and redefined the nature of the regulatory treatment of computer networks over communications networks. The Author reviews Computer I, in which the FCC first attempted to divide the world technologically between computers that ran communications networks ( pure communications ) and computers at the end of telephone lines with which people interacted ( pure data processing ). In Computer II, the FCC reclassified the computer world on the basis of the services provided-basic or enhanced. The FCC\u27s third and final attack on the issue, Computer III, retained the conceptual framework, but redetermined how the policy objectives would be implemented. The Author concludes that the actions taken by the FCC may not have invented the Internet, but they certainly contributed to its success

The Legacy of the Federal Communications Commission’s Computer Inquiries

The FCC and the computer industry have learned much in the 35 years since the agency first began to regulate computer networks. Safeguards were imposed on common carriers for the benefit of the networks. This Article examines the so-called Computer Inquiries and how they have repeatedly re-examined and redefined the nature of the regulatory treatment of computer networks over communications networks. The Author reviews Computer I, in which the FCC first attempted to divide the world technologically between computers that ran communications networks ( pure communications ) and computers at the end of telephone lines with which people interacted ( pure data processing ). In Computer II, the FCC reclassified the computer world on the basis of the services provided-basic or enhanced. The FCC\u27s third and final attack on the issue, Computer III, retained the conceptual framework, but redetermined how the policy objectives would be implemented. The Author concludes that the actions taken by the FCC may not have invented the Internet, but they certainly contributed to its success

Experiments in cooperative manipulation: A system perspective

In addition to cooperative dynamic control, the system incorporates real time vision feedback, a novel programming technique, and a graphical high level user interface. By focusing on the vertical integration problem, not only these subsystems are examined, but also their interfaces and interactions. The control system implements a multi-level hierarchical structure; the techniques developed for operator input, strategic command, and cooperative dynamic control are presented. At the highest level, a mouse-based graphical user interface allows an operator to direct the activities of the system. Strategic command is provided by a table-driven finite state machine; this methodology provides a powerful yet flexible technique for managing the concurrent system interactions. The dynamic controller implements object impedance control; an extension of Nevill Hogan's impedance control concept to cooperative arm manipulation of a single object. Experimental results are presented, showing the system locating and identifying a moving object catching it, and performing a simple cooperative assembly. Results from dynamic control experiments are also presented, showing the controller's excellent dynamic trajectory tracking performance, while also permitting control of environmental contact force

What does it take to be an effective educational adviser in Indonesia and Thailand?

Structured group interviews with Thai and Indonesian educators indicate that expatriate advisers require a wide range of personal and professional qualities to be effective: they must have expertise, be able to establish and maintain good relationships with people, be well organised and effective teachers, and transfer information and skills that are applicable and of benefit to the nation. None of these qualities is simple or uni-dimensional. They [The?]study shows, for example, that 'expertise' has several elements including technical expertise, cultural knowledge, language ability and expertise in education. More recent research with Indonesian medical educators indicates that different professional groups may have quite different expectations of advisers from other groups in the same country. Practical implications of the findings are in overseas project design, management and placement of personnel, professional development of experts, and in the design, implementation and evaluation of teaching and training

Computed torque control of a free-flying cooperat ing-arm robot

The unified approach to solving free-floating space robot manipulator end-point control problems is presented using a control formulation based on an extension of computed torque. Once the desired end-point accelerations have been specified, the kinematic equations are used with momentum conservation equations to solve for the joint accelerations in any of the robot's possible configurations: fixed base or free-flying with open/closed chain grasp. The joint accelerations can then be used to calculate the arm control torques and internal forces using a recursive order N algorithm. Initial experimental verification of these techniques has been performed using a laboratory model of a two-armed space robot. This fully autonomous spacecraft system experiences the drag-free, zero G characteristics of space in two dimensions through the use of an air cushion support system. Results of these initial experiments are included which validate the correctness of the proposed methodology. The further problem of control in the large where not only the manipulator tip positions but the entire system consisting of base and arms must be controlled is also presented. The availability of a physical testbed has brought a keener insight into the subtleties of the problem at hand