Diagnostic procedures for antenna hydraulic drive systems
Diagnostic, testing, and maintenance procedures for hydraulic drive systems for large steerable antennas
Lombardo, J. J.↗
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Results for “Drive systems”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Traction drive system design considerations for a lunar roving vehicle
Optimal traction drive system design for lunar roving vehicle, considering weight, energy consumption, operational flexibility, power supply, motor and power train
Doran, B. J.↗
Drive System Enhancement in the NASA Lewis Research Center Supersonic Wind Tunnels
An overview of NASA Lewis' Aeropropulsion Wind Tunnel Productivity Improvements was presented at the 19th AIAA Advanced Measurement & Ground Testing Technology Conference. Since that time Lewis has implemented subsonic operation in their 10- by 10-Foot Supersonic Wind Tunnel as had been proven viable in the 8- by 6 and 9- by 15-Foot Wind Tunnel Complex and discussed at the aforementioned conference. In addition, two more years of data have been gathered to help quantify the true productivity increases in these facilities attributable to the drive system and operational improvements. This paper was invited for presentation at the 20th Advanced Measurement and Ground Testing Conference to discuss and quantify the productivity improvements in the 10- by 10 SWT since the implementation of less than full complement motor operation. An update on the increased productivity at the 8- by 6 and 9- by 15-Foot facility due to drive system enhancements will also be presented.
Becks, Edward A.↗
Advanced propfan drive system characteristics and technology needs
Characteristics of a single-rotation drive system for an advanced turboprop engine are described. The gearbox is designed for a 10,000 shp three-spool, free-turbine engine and is installed in a wing-mounted nacelle. An offset gearbox from an earlier APET study provided the background for the preliminary design and benefit analysis for a 1990s advanced technology versus 1980s state-of-the-art gearbox. High efficiencies were achieved for both designs with inherently high life goals. Increases in design allowables for gears, bearings, and lubricants resulted in improvements for the 1990s design.
Anderson, R. D.↗
Promising Electric Aircraft Drive Systems
An overview of electric aircraft propulsion technology performance thresholds for key power system components is presented. A weight comparison of electric drive systems with equivalent total delivered energy is made to help identify component performance requirements, and promising research and development opportunities.
Dudley, Michael R.↗
Designing an Intrusion Proof Adjustable Speed Drive System Controlling a Critical Process
In this paper, an intrusion proof adjustable speed drive system controlling a critical process in an industrial control system is detailed. In such a system, should the motor speed sensor signal data be compromised and/or altered via a cyber-attack, the system can potentially be unregulated, over speed and/or malfunction thereby disrupting the critical process. The proposed active detection scheme detailed in this paper introduces a private (secret) random signal termed as "watermark" into the inverter control signal that determines the PWM gating signals of the DC-AC inverter powering the motor. The watermarking signal introduced into the PWM modulation for the DC-AC inverter is shown to propagates its unique signature, which appears in all sensors signals at the inverter output such as voltage/current/speed used to control the motor. Now employing the measured data (from sensors), two statistical variance tests are conducted to identify anomalies if any in the presence of the watermarking signal. It is shown when an intrusion occurs to manipulate the sensor data to disturb and/or destabilize the process, the proposed tests immediately display a high value indicating a compromise in sensor data. It is shown that the proposed system is capable of immediate detection of a sophisticated attacks such as record/reply attack in which the actual speed sensor is disconnected and a prerecorded speed signal from the past of the same magnitude is played back to the controller. Several types of cyber-attacks such as speed reduction/increase including vibration have been tested. Extensive simulation results verify the proposed concepts. Experimental results will be discussed in the conference presentation.
Alotaibi, Faris↗
Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components
Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests
high speed imaging↗
Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components
Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests.
composite materials↗
Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components
Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests.
Kohlman, Lee↗
Concepts for Multi-Speed Rotorcraft Drive System - Status of Design and Testing at NASA GRC
In several studies and on-going developments for advanced rotorcraft, the need for variable multi-speed capable rotors has been raised. Speed changes of up to 50 have been proposed for future rotorcraft to improve vehicle performance. A rotor speed change during operation not only requires a rotor that can perform effectively over the operating speedload range, but also requires a propulsion system possessing these same capabilities. A study was completed investigating possible drive system arrangements that can accommodate up to a 50 speed change. Key drivers were identified from which simplicity and weight were judged as central. This paper presents the current status of two gear train concepts coupled with the first of two clutch types developed and tested thus far with focus on design lessons learned and areas requiring development. Also, a third concept is presented, a dual input planetary differential as leveraged from a simple planetary with fixed carrier.
transmission↗
Concepts for Multi-Speed Rotorcraft Drive System - Status of Design and Testing at NASA GRC
In several studies and on-going developments for advanced rotorcraft, the need for variable/multi-speed capable rotors has been raised. Speed changes of up to 50 percent have been proposed for future rotorcraft to improve vehicle performance. A rotor speed change during operation not only requires a rotor that can perform effectively over the operating speed/load range, but also requires a propulsion system possessing these same capabilities. A study was completed investigating possible drive system arrangements that can accommodate up to a 50 percent speed change. Key drivers were identified from which simplicity and weight were judged as central. This paper presents the current status of two gear train concepts coupled with the first of two clutch types developed and tested thus far with focus on design lessons learned and areas requiring development. Also, a third concept is presented, a dual input planetary differential as leveraged from a simple planetary with fixed carrier.
variable-speed↗
Free-piston Stirling hydraulic engine and drive system for automobiles
The calculated fuel economy for an automotive free piston Stirling hydraulic engine and drive system using a pneumatic accumulator with the fuel economy of both a conventional 1980 spark ignition engine in an X body class vehicle and the estimated fuel economy of a 1984 spark ignition vehicle system are compared. The results show that the free piston Stirling hydraulic system with a two speed transmission has a combined fuel economy nearly twice that of the 1980 spark ignition engine - 21.5 versus 10.9 km/liter (50.7 versus 25.6 mpg) under comparable conditions. The fuel economy improvement over the 1984 spark ignition engine was 81 percent. The fuel economy sensitivity of the Stirling hydraulic system to system weight, number of transmission shifts, accumulator pressure ratio and maximum pressure, auxiliary power requirements, braking energy recovery, and varying vehicle performance requirements are considered. An important finding is that a multispeed transmission is not required. The penalty for a single speed versus a two speed transmission is about a 12 percent drop in combined fuel economy to 19.0 km/liter (44.7 mpg). This is still a 60 percent improvement in combined fuel economy over the projected 1984 spark ignition vehicle.
Beremand, D. G.↗
Concepts for Variable/Multi-Speed Rotorcraft Drive System
In several recent studies and on-going developments for advanced rotorcraft, the need for variable or multi-speed capable rotors has been raised. A speed change of up to 50 percent has been proposed for future rotorcraft to improve overall vehicle performance. Accomplishing rotor speed changes during operation requires both a rotor that can perform effectively over the operation speed/load range, and a propulsion system that can enable these speed changes. A study has been completed to investigate possible drive system arrangements that can accommodate up to the 50 percent speed change. Several concepts will be presented and evaluated. The most promising configurations will be identified and developed for future testing in a sub-scaled test facility to validate operational capability.
Stevens, Mark A.↗
Variable/Multispeed Rotorcraft Drive System Concepts
Several recent studies for advanced rotorcraft have identified the need for variable, or multispeed-capable rotors. A speed change of up to 50 percent has been proposed for future rotorcraft to improve vehicle performance. Varying rotor speed during flight not only requires a rotor capable of performing effectively over the extended operation speed and load range, but also requires an advanced propulsion system to provide the required speed changes. A study has been completed, which investigated possible drive system arrangements to accommodate up to the 50 percent speed change. These concepts are presented. The most promising configurations are identified and will be developed for future validation testing.
Stevens, Mark A.↗
Development of a drive system for a sequential space camera contract modification 4(S)
The brush type dc motor and clutch were eliminated from the design of the 16 mm space sequential camera design and replaced by an electronically commutated motor. The new drive system reduces the current consumption at 24 fps to 220 mA. The drive can be programmed and controlled externally from the multipurpose programmable timer/intervalometer, as well as being controlled locally from the camera.
Sharpsteen, J. T.↗
Thermal/structural analysis of the shaft-disk region of a fan drive system
In January 1989, a mishap occurred in the National Transonic Facility wind tunnel at NASA-Langley. It is believed that the failure of an insulation retainer holding foam insulation around the exterior of the fan drive shaft resulted in the subsequent damage to other components in the tunnel. The effect was determined of removing the external thermal insulation on the shaft would have on the stresses on the shaft, disk and bolts holding the two together. To accomplish this, a detailed thermal/structural finite element analysis of the shaft-disk interface was performed. The maximum stresses on the three components were determined for several configurations and conditions with and without the external thermal insulation, and then these results were compared to the original analyses to access the effect of removing the external thermal insulation on the proposed future operation of the shaft/disk structures of the fan drive system. Although the stresses were higher without the external insulation, the stresses did meet all stress criteria. In addition, all stresses were within the infinite life regime of the Modified Goodman diagram. Therefore, it was determined that the structural integrity of the shaft-disk region is not compromised if the external insulation is removed.
Gregory, Peyton B.↗
Development of cable drive systems for an automated assembly project
In a robotic assembly project, a method was needed to accurately position a robot and a structure which the robot was to assemble. The requirements for high precision and relatively long travel distances dictated the use of cable drive systems. The design of the mechanisms used in translating the robot and in rotating the assembly under construction is discussed. The design criteria are discussed, and the effect of particular requirements on the design is noted. Finally, the measured performance of the completed mechanism is compared with design requirements.
Monroe, Charles A., Jr.↗
Computational fluid dynamics (CFD) in the design of a water-jet-drive system
NASA/Marshall Space Flight Center (MSFC) has an ongoing effort to transfer to industry the technologies developed at MSFC for rocket propulsion systems. The Technology Utilization (TU) Office at MSFC promotes these efforts and accepts requests for assistance from industry. One such solicitation involves a request from North American Marine Jet, Inc. (NAMJ) for assistance in the design of a water-jet-drive system to fill a gap in NAMJ's product line. NAMJ provided MSFC with a baseline axial flow impeller design as well as the relevant working parameters (rpm, flow rate, etc.). This baseline design was analyzed using CFD, and significant deficiencies identified. Four additional analyses were performed involving MSFC changes to the geometric and operational parameters of the baseline case. Subsequently, the impeller was redesigned by NAMJ and analyzed by MSFC. This new configuration performs significantly better than the baseline design. Similar cooperative activities are planned for the design of the jet-drive inlet.
Garcia, Roberto↗