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An electromechanical actuation system for an expendable launch vehicleA major effort at the NASA Lewis Research Center in recent years has been to develop electro-mechanical actuators (EMA's) to replace the hydraulic systems used for thrust vector control (TVC) on launch vehicles. This is an attempt ot overcome the inherent inefficiencies and costs associated with the existing hydraulic structures. General Dynamics Space Systems Division, under contract to NASA Lewis, is developing 18.6 kW (25 hp), 29.8 kW (40 hp), and 52.2 kW (70 hp) peak EMA systems to meet the power demands for TVC on a family of vehicles developed for the National Launch System. These systems utilize a pulse population modulated converter and field-oriented control scheme to obtain independent control of both the voltage and frequency. These techniques allow an induction motor to be operated at its maximum torque at all times. At NASA Lewis, we are building on this technology to develop our own in-house system capable of meeting the peak power requirements for an expendable launch vehicle (ELV) such as the Atlas. Our EMA will be capable of delivering 22.4 kW (30 hp) peak power with a nominal of 6.0 kW (8 hp). This system differs from the previous ones in two areas: (1) the use of advanced control methods, and (2) the incorporation of built-in-test. The advanced controls are essential for minimizing the controller size, while the built-in-test is necessary to enhance the system reliability and vehicle health monitoring. The ultimate goal of this program is to demonstrate an EMA which will be capable of self-test and easy integration into other projects. This paper will describe the effort underway at NASA Lewis to develop an EMA for an Atlas class ELV. An explanation will be given for each major technology block, and the status of each major technology block and the status of the overall program will be reported.
Document ID
19920021067
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Burrows, Linda M.
(NASA Lewis Research Center Cleveland, OH, United States)
Roth, Mary Ellen
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1992
Subject Category
Launch Vehicles And Space Vehicles
Report/Patent Number
E-7202
NASA-TM-105774
NAS 1.15:105774
Meeting Information
Meeting: Intersociety Energy Conversion Engineering Conference
Location: San Diego, CA
Country: United States
Start Date: August 3, 1992
End Date: August 7, 1992
Sponsors: SAE, ACS, ASME, IEEE, AIAA, AIChE, ANS
Accession Number
92N30310
Funding Number(s)
PROJECT: RTOP 506-41-41
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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