Inner loop integrator feasibility study Final report
Feasibility study of hydromechanical actuator using analog computer simulation
Goldstein, S. M.↗
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Results for “ANALOG SIMULATION”
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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Dynamic behavior of thrust-balance systems.
Dynamic behavior of series and parallel flow thrust-balance systems for compressible and incompressible flow, using analog computer simulation
Bickford, L. L.↗
On-line simulation of block-diagram systems.
Time and space on-line simulation of analog, digital and hybrid block diagram systems
Dertouzos, M. L.↗
Analog computer studies of a 2 to 10 kilowatts electric Brayton cycle space power system including startup and shutdown.
Analog computer simulation of single shaft Brayton cycle system dynamics, including startup and shutdown transients
Cantoni, D. A.↗
Analog computer study of design parameter effects on the stability of a direct acting gas pressure regulator
Analog computer simulation of design parameter effects on stability of direct acting gas pressure regulator based on Brayton cycle space power generator
Dustin, M. O.↗
Thermionic Diode Kinetics Experiment - Design and startup
Thermionic Diode Kinetics Experiment with on-line analog computer simulation, investigating thermionic reactor powerplant dynamics and control by nonnuclear means
Ernst, D.↗
Flight instrument and telemetry response and its inversion
Mathematical models of rate gyros, servo accelerometers, pressure transducers, and telemetry systems were derived and their parameters were obtained from laboratory tests. Analog computer simulations were used extensively for verification of the validity for fast and large input signals. An optimal inversion method was derived to reconstruct input signals from noisy output signals and a computer program was prepared.
Weinberger, M. R.↗
Hypersonic and transonic buzz measurements on the lower pitch flap of the M2-F2 lifting entry configuration
Free-oscillation damping measurements at hypersonic and transonic Mach numbers are presented for the lower pitch flap of the M2-F2 reentry vehicle. For the flow and model conditions tested, the damping measurements indicate the absence of hypersonic buzz instability for flap rotation frequencies of 47.3 Hz, 153 Hz, and 360 Hz, the presence of transonic buzz for 47.3 Hz flap, and the absence of transonic buzz for a 115 Hz flap. There are not enough flap damping data for an error estimate based on repeatability, but a partial damping calibration is presented in which an analog computer simulation of random flap response for a known flap damping is fed into the autocorrelation computer and filter combination used for most of the damping measurements.
Warner, R. W.↗
Gas-injection-start and shutdown characteristics of a 2-kilowatt to 15-kilowatt Brayton power system
Two methods of starting the Brayton power system have been considered: (1) using the alternator as a motor to spin the Brayton rotating unit (BRU), and (2) spinning the BRU by forced gas injection. The first method requires the use of an auxiliary electrical power source. An alternating voltage is applied to the terminals of the alternator to drive it as an induction motor. Only gas-injection starts are discussed in this report. The gas-injection starting method requires high-pressure gas storage and valves to route the gas flow to provide correct BRU rotation. An analog computer simulation was used to size hardware and to determine safe start and shutdown procedures. The simulation was also used to define the range of conditions for successful startups. Experimental data were also obtained under various test conditions. These data verify the validity of the start and shutdown procedures.
Cantoni, D. A.↗
Advanced study of video signal processing in low signal to noise environments
A nonlinear analysis of a multifilter phase-lockloop (MPLL) by using the method of harmonic balance is presented. The particular MPLL considered has a low-pass filter and a band-pass filter in parallel. An analytic expression for the relationship between the input signal phase deviation and the phase error is determined for sinusoidal FM in the absence of noise. The expression is used to determine bounds on the proper operating region for the MPLL and to investigate the jump phenomenon previously observed. From these results the proper modulation index, modulating frequency, etc. used for the design of a MPLL are determined. Data for the loop unlock boundary obtained from the theoretical expression are compared to data obtained from analog computer simulations of the MPLL.
Carden, F.↗
Brake control system modification, augmentor Wing Jet STOL Research Airplane (AWJSRA)
The braking system for a short takeoff aircraft is discussed and the deficiencies are described. The installation of a Boeing 727 aircraft brake system was made to correct the deficiencies. Tests of the modified system were conducted using an analog computer/hardware simulator. Actual performance tests were conducted and the characteristics of the system were satisfactory.
Amberg, R. L.↗
Analysis of self-oscillating dc-to-dc converters
The basic operational characteristics of dc-to-dc converters are analyzed along with the basic physical characteristics of power converters. A simple class of dc-to-dc power converters are chosen which could satisfy any set of operating requirements, and three different controlling methods in this class are described in detail. Necessary conditions for the stability of these converters are measured through analog computer simulation whose curves are related to other operational characteristics, such as ripple and regulation. Further research is suggested for the solution of absolute stability and efficient physical design of this class of power converters.
Burger, P.↗
Redundant actuator development program
Two concepts of redundant secondary actuator mechanization, applicable to future advanced flight control systems, were studied to quantitatively assess their design applicability to an AST. The two actuator concepts, a four-channel, force summed system and a three-channel, active/standby system have been developed and evaluated through analysis, analog computer simulation, and piloted motion simulation. The quantitative comparison of the two concepts indicates that the force summed concept better meet performance requirements, although the active/standby is superior in other respects. Both concepts are viable candidates for advanced control application dependent on the specific performance requirements.
Chenoweth, C. C.↗
Analysis of a class of pulse modulated dc-to-dc power converters
The basic operational characteristics of dc-to-dc converters are analyzed. The basic physical characteristics of power converters are identified. A simple class of dc-to-dc power converters is chosen which could satisfy any set of operating requirements. Three different controlling methods in this class are described in detail. Necessary conditions for the stability of these converters are measured through analog computer simulation. These curves are related to other operational characteristics, such as ripple and regulation. Finally, further research is suggested for the solution of the physical design of absolutely stable, reliable, and efficient power converters of this class.
Burger, P.↗
Economic trade-offs between the performance of collector thermal performance tests on a Solar Simulator as opposed to outdoor testing
In 1976 a large Solar Simulator was designed and installed at Marshall Space Flight Center. This Solar Simulator is the largest of its type in the country and has a 'working' area of 4 ft x 8 ft. Recently completed comparison tests show excellent correlation with data collected in the natural sun. The Solar Simulator has been in operation since September 1976 and the costs of operation are now determinable together with the cost of design and construction. The authors compare the total operational costs of obtaining test data using the simulator with analogous costs of testing in the natural sun. In addition, productivity is compared.
Reily, J. C.↗
Superrotation planetary atmospheres: Mechanical analogy, angular momentum budget and simulation of the spin up process
Superrotation rates observed in planetary atmospheres are analyzed based on the concept of a thermally driven zonally symmetric circulation. Specifically, how this superrotation is produced and maintained against the tendency for friction to oppose differential motions between the atmosphere and the underlying planet is addressed. The time evolution of a fluid leading from corotation under uniform heating to superrotation under globally nonuniform heating is simulated using a three dimensional zonally symmetric spectral model and Laplace transformation. The increased tendency toward geostrophy combined with the increase of surface pressure toward the poles (due to meridional mass transport), induces the atmosphere to subrotate temporarily at lower altitudes. The resulting viscous shear near the surface thus permits angular momentum to flow from the planet into the atmosphere where it propagates upwards and, combined with the change in moment of inertia, produces large superrotation rates at higher viscosities.
Mayr, H. G.↗
Advanced dc motor controller for battery-powered electric vehicles
A motor generation set is connected to run from the dc source and generate a voltage in the traction motor armature circuit that normally opposes the source voltage. The functional feasibility of the concept is demonstrated with tests on a Proof of Principle System. An analog computer simulation is developed, validated with the results of the tests, applied to predict the performance of a full scale Functional Model dc Controller. The results indicate high efficiencies over wide operating ranges and exceptional recovery of regenerated energy. The new machine integrates both motor and generator on a single two bearing shaft. The control strategy produces a controlled bidirectional plus or minus 48 volts dc output from the generator permitting full control of a 96 volt dc traction motor from a 48 volt battery, was designed to control a 20 hp traction motor. The controller weighs 63.5 kg (140 lb.) and has a peak efficiency of 90% in random driving modes and 96% during the SAE J 227a/D driving cycle.
Belsterling, C. A.↗
Periodic control of the individual-blade-control helicopter rotor
Results of an investigation into methods of controller design for an individual helicopter rotor blade in the high forward-flight speed regime are described. This operating condition poses a unique control problem in that the perturbation equations of motion are linear with coefficients that vary periodically with time. The design of a control law was based on extensions to modern multivariate synthesis techniques and incorporated a novel approach to the reconstruction of the missing system state variables. The controller was tested on both an electronic analog computer simulation of the out-of-plane flapping dynamics, and on a four foot diameter single-bladed model helicopter rotor in the M.I.T. 5x7 subsonic wind tunnel at high levels of advance ratio. It is shown that modal control using the IBC concept is possible over a large range of advance ratios with only a modest amount of computational power required.
Mckillip, R. M., Jr.↗