Abstract for the September 19, 1997 Robotics Institute Seminar

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NIST Construction Automation Program

Bill Stone
National Institute for Standards and Technology (NIST)

4:15pm, Adamson Wing, Baker Hall

The speaker will describe the sensing, calibration, and actuator system used to convert an existing 30-ton high bay bridge crane at NIST to computer control for automated placement of construction components. The system is being designed to permit either telepresent or fully autonomous assembly of a subset of a full-scale process plant. In order to achieve six degree-of-freedom manipulation of the individual components the traditional bridge crane cable and hook has been replaced by TETRA, an inverted cable operated Stewart platform equipped with various manipulators attached to a suspended triangular platform. The sensing systems are largely concentrated into three categories: displacement, force, and state sensors. What makes this application unique is the scale of the robot: the crane spans 23 m, has a run length of 32 m and a working volume height of 24 m. This scale, and a need for clean operation without power and communications wires, has led to a control system based on discrete sensing packets. The packets consist of one or several force, displacement, or state sensors (limit switches, hall effect chips) which receive their power locally and are connected to local microcontrollers. Each microcontroller, in turn, broadcasts its data via wireless ethernet to a master controller which then communicates with the world via a high speed ATM link. Issues relating to selection, implementation, and calibration of the sensor array needed to operate this large construction robot will be discussed.

Biographical Sketch:
Dr. Stone is the Principal Investigator on several projects including the development of Non-Line-of-Sight (NLS) real time construction metrology systems as part of the NIST construction automation initiative; the development of Virtual Construction Site simulators; experimental research and the development of design guidelines for novel precast prestressed moment resisting frames; and the development of automated procedures for the design of ductile bridge columns constructed in zones of seismic risk. Previous assignments have included engineering related to the conversion of Space Shuttle external fuel tanks into safe, low cost laboratory facilities in low earth orbit and the development of a microprocessor controlled "intelligent" shock loading system for identification and active control of orbiting structures when subjected to dynamic loads. Dr. Stone has also served as principal investigator in the NIST program to study performance of full-scale bridge components subjected to simulated earthquakes. In this capacity he was responsible for the design and development of the NIST Large Scale Structural Testing Facility.

For appointments, please contact the host, Jim Osborn: oz@frc.ri.cmu.edu, 412.268.6553

You can also visit the Construction Automation home page.

Last Modified on: Thu Sep 18, 1997

This appears on the World Wide Web at http://www.frc.ri.cmu.edu/~mcm/seminar.html

Martin C. Martin, <mm+@cmu.edu>