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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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At least 199 records · Page 11

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NASA NTRS1973

Underwater space suit pressure control regulator

A device is reported for regulating the pneumatic pressure in a ventilated space suit relative to the pressure imposed on the suit when being worn by a person underwater to simulate space environment for testing and experimentation. A box unit located on the chest area of the suit comprises connections for suit air supply and return lines and carries a regulator valve that stabilizes the air pressure differential between the inside and outside of the suit. The valve and suit pressure is controlled by the suit occupant and the valve includes a mechanism for quickly dumping the suit pressure in case of emergency. Pressure monitoring and relief devices are also included in the box unit.

Aldrich, B. R.↗

NASA NTRS1972

The Right to Regulate

An introduction to the historical and constitutional framework of industry regulation by local and Federal Governments is presented. Problems of the confiscation of private property without due process, government control and the rights and duties of the regulated industry are discussed.

Vittek, J. F.↗

NASA NTRS1973

Linearized stability analysis and design of a flyback dc-dc boost regulator.

Analytic expressions for the small-signal power-stage describing functions of a switched dc-dc boost regulator are derived from an approximate continuous circuit model which is developed by a time-averaging technique. Closed-loop stability is attained through the design of frequency compensation of the loop gain. Open- and closed-loop regulator output impedances are derived from the linearized models for the given configuration. The analysis and design are compared with and confirmed by breadboard measurements.

Wester, G. W.↗

NASA NTRS1974

Automatic controls and regulators: A compilation

Devices, methods, and techniques for control and regulation of the mechanical/physical functions involved in implementing the space program are discussed. Section one deals with automatic controls considered to be, essentially, start-stop operations or those holding the activity in a desired constraint. Devices that may be used to regulate activities within desired ranges or subject them to predetermined changes are dealt with in section two.

Source record↗

NASA NTRS1975

Development of a breadboard design of a high-performance, high-reliability switching regulator

A comparison of two potential conversion methods, the series inverter and the inductive energy transfer (IET) conversion technique, is presented. The investigations showed that a characteristic of the series inverter circuit (high equalizing current values in each half cycle) could not be accomplished with available components, and the investigations continued with the IET circuit only. An IET circuit system was built with the use of computer-aided design in a 2, 4, and 8 stage configuration, and these stages were staggered 180, 90, and 45 degrees, respectively. All stages were pulsewidth modulated to regulate over an input voltage range from 200 to 400 volts dc at a regulated output voltage of 56 volts. The output power capability was 100 to 500 watts for the 2 and 8 stage configuration and 50 to 250 watts for the 4 stage configuration. Equal control of up to eight 45 degree staggered stages was accomplished through the use of a digital-to-analog control circuit. Equal power sharing of all stages was achieved through a new technique using an inductively coupled balancing circuit. Conclusions are listed.

Lindena, S. J.↗

NASA NTRS1975

Effects of automobile steering characteristics on driver vehicle system dynamics in regulation tasks

A regulation task which subjected the automobile to a random gust disturbance which is countered by driver control action is used to study the effects of various automobile steering characteristics on the driver/vehicle system. The experiments used a variable stability automobile specially configured to permit insertion of the simulated gust disturbance and the measurement of the driver/vehicle system characteristics. Driver/vehicle system dynamics were measured and interpreted as an effective open loop system describing function. Objective measures of system bandwidth, stability, and time delays were deduced and compared. These objective measures were supplemented by driver ratings. A tentative optimum range of vehicle dynamics for the directional regulation task was established.

Mcruer, D. T.↗

NASA NTRS1974

Stability analysis and compensation of a boost regulator with two-loop control

A useful stability measure has been demonstrated by Wester (1973) for switching regulators with a single feedback loop by applying the Nyquist criterion to the approximate loop gain determined by a time-averaging technique. This approach is extended and applied to the characterization, stability analysis, and compensation design of a switching regulator with two-loop control. The role and relative significance of each control loop is clarified on the basis of a description of circuit operation, and the major and minor loops are identified. In view of the inapplicability of linear feedback theory, describing functions of the feedback loops and power stage are derived, using small-signal analysis. Several phenomena revealed from an analysis of the major loop gain are discussed.

Wester, G. W.↗

NASA NTRS1975

Self-tuning regulators

The results of a research project are discussed for self-tuning regulators for active control. An algorithm for the self-tuning regulator is described as being stochastic, nonlinear, time variable, and not trivial.

Astrom, K. J.↗

NASA NTRS1977

Design of turbofan engine controls using output feedback regulator theory

A multivariable control design procedure based on output feedback regulator (OFR) theory is applied to the F100 turbofan engine. Results for the OFR design are compared to a design based on linear quadratic regulator (LQR) theory. The OFR feedback control is designed in the full order state space and thus eliminates any need for model reduction techniques. Using the performance measure and control structure of the LQR design, an equivalent OFR feedback control is obtained. The flexibility of the OFR as a control design procedure is demonstrated, and differing feedback control structures are evaluated.

Merrill, W. C.↗

NASA NTRS1979

Voltage regulator for solar panels

Shunt voltage regulators for solar panels uses internal resistance of panel to control its output voltage. Regulator can be scaled up for high-current solar panels by adding more transistors.

Casad, T. A.↗

NASA NTRS1969

Transformer regulated self-stabilizing chopper

A self-stabilizing voltage regulator is described. Direct current voltage regulation employing a series transistor rendered conductive during various portions of a cycle is controlled by saturation of an autotransformer. The constant volt-second capacity of the transformer provides conduction time inverse to the input voltage whereby average output voltage is maintained constant. Conduction commenced in response to short gate signals, and resistor feedback for degenerative turn-off of the transistor was after transformer saturation. Standard output filters are also included.

Raposa, F. L.↗

NASA NTRS1977

Design of turbofan engine controls using output feedback regulator theory

A multivariable control design procedure based on output feedback regulator (OFR) theory is applied to the F100 turbofan engine. Results for the OFR design are compared to a design based on linear quadratic regulator (LQR) theory. This LQR design was obtained as part of the F100 Multivariable Control Synthesis (MVCS) program. In the MVCS program the LQR feedback control was designed in a reduced dimension state space and then applied to the original system. However, the OFR feedback control is designed in the full order state space and thus eliminates any need for model reduction techniques. Using the performance measure and control structure of the MVCS program LQR design, an equivalent OFR feedback control is obtained. The flexibility of the OFR as a control design procedure is demonstrated and differing feedback control structures are evaluated.

Merrill, W. C.↗

NASA NTRS1978

Physiologic regulation of body energy storage

Both new and published data (rats, mice, and human beings) on three parameters - fat mass, fat-free body mass (FFBM), and total body mass in some cases - are evaluated. Steady state values of the parameters are analyzed for changes in response to specific perturbing agents and for their frequency distributions. Temporal sequences of values on individuals are examined for evidence of regulatory responses. The results lead to the hypothesis that the FFBM is regulated, but probably not as a unit, and that mass of fat is regulated with a high priority near the range extremes but with a much lower priority in the mid-range. Properties and advantages of such a mechanism are discussed.

Pitts, G. C.↗

NASA NTRS1979

Low-noise current regulator

Modification of conventional regulator minimizes current drift. Current to be regulated flows through sensing resistor in series with load, producing voltage that is fed into operational amplifier. Other input into amplifier is reference voltage from Zener diode network.

Bunn, J.↗

NASA NTRS1979

Bifunctional gas-flow regulator

Simple modification converts conventional high-pressure regulator to combination pressure-regulator/shutoff valve. Modification entails adding second diaphragm and pressure compartment. Modified valve is switched between its two functions by external two-position low-pressure valve.

Koch, E. F.↗

NASA NTRS1979

Development of high reliability, high frequency power conditioning models of converter regulators

High efficiency conversion, regulation, and filtering techniques are discussed for power using high conversion frequencies; i.e., in the order of 1 to 5 MHz for converters having total output power capability in the order of 20 watts and 200 to 500 KHz for converters having total output powers in excess of 200 watts. Work centered on areas of component selection, material selection, optimization of the various types of circuits required, and the selection of materials for and design of magnetic components. These techniques were then applied to the design of two sample converters, one a medium power instrument type converter and the second a high power converter representative of a primary spacecraft converter regulator. The configuration and performance of the two converters is reported and discussed.

Rochussen, A. W.↗

NASA NTRS1979

Voltage regulator for battery power source

A bipolar transistor in series with the battery as the control element also in series with a zener diode and a resistor is used to maintain a predetermined voltage until the battery voltage decays to very nearly the predetermined voltage. A field effect transistor between the base of the bipolar transistor and a junction between the zener diode and resistor regulates base current of the bipolar transistor, thereby regulating the conductivity of the bipolar transistor for control of the output voltage.

Black, J. M.↗

NASA NTRS1978

Global analysis of a buck regulator

Sufficient conditions for global stability of a buck regulator using a discrete control law are found. The method of paired systems and Liapunov functions are used to establish global stability and to study the convergence of the regulator. A heuristic argument is given that the optimal switching curves associated with the paired continuous systems approximate the optimal switching curves of the discrete systems.

Edwards, D. B.↗