An Application of "High Authority/Low Authority Control" & "Positivity"

Control Dynamics Company CDy, in conjunction with NASA Marshall Space Flight Center MSFC, has supported the U.S. Air Force Wright Aeronautical Laboratory AFWAL in conducting an investigation of the implementation of several Department of Defense controls techniques. These techniques are to provide vibration suppression and precise attitude control for flexible space structures. AFWAL issued a contract to Control Dynamics to perform this effort under the Active Control Technique Evaluation for Spacecraft ACES Program. Dr. Henry B. Waites MSFC was the Principal Investigator Dr. George B. Doane III CDy was the Program Manager, and Dr. R. Dennis Irwin formerly CDy, presently Ohio University was the Project Leader. The High Authority ControlLow Authority Control HACLAC and Positivity controls techniques, which were cultivated under the DARPA Active Control of Space Structures ACOSS Program, were applied to a structural model of the NASAMSFC Ground Test Facility ACES configuration. Mr. Danny K. Tollison performed the HACLAC evaluation, and Mr. Jeffrey Lucas performed the Positivity evaluation. The control system designs were accomplished and linear post-analyses of the closed-loop systems are provided. The control system designs take into account effects of sampling and delay in the control computer. Nonlinear simulation runs were used to verify the control system designs and implementations in the facility control computers. Finally, test results are given to verify operations of the control systems in the test facility.