Smart motor technology

Current spacecraft design relies upon microprocessor control; however, motors usually require extensive additional electronic circuitry to interface with these microprocessor controls. An improved control technique that allows a smart brushless motor to connect directly to a microprocessor control system is described. An actuator with smart motors receives a spacecraft command directly and responds in a closed loop control mode. In fact, two or more smart motors can be controlled for synchronous operation

Dual drive actuators

A new class of electromechanical actuators is described. These dual drive actuators were developed for the NASA-JPL Galileo Spacecraft. The dual drive actuators are fully redundant and therefore have high inherent reliability. They can be used for a variety of tasks, and they can be fabricated quickly and economically

Brushless DC motor control system responsive to control signals generated by a computer or the like

A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The motor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor be regulated by applying a separate control signal and each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period

The Galeleo spacecraft magnetometer boom

The Galileo spacecraft utilizes a deployable lattice boom to position three science instruments at remote distances from the spacecraft body. An improved structure and mechanism to precisely control deployment of the boom, and the unique deployment of an outer protective cover are described

Semiconductor surface protection material

A method and a product for protecting semiconductor surfaces is disclosed. The protective coating material is prepared by heating a suitable protective resin with an organic solvent which is solid at room temperature and converting the resulting solution into sheets by a conventional casting operation. Pieces of such sheets of suitable shape and thickness are placed on the semiconductor areas to be coated and heat and vacuum are then applied to melt the sheet and to drive off the solvent and cure the resin. A uniform adherent coating, free of bubbles and other defects, is thus obtained exactly where it is desired

INVESTIGATION OF LIGHT TRANSPORT AND SCATTERING IN TURBULENT CLOUDS: SIMULATIONS AND LABORATORY MEASUREMENTS

A better understanding of light transport and scattering in turbulent clouds is needed for more accurate remote sensing, improved imaging and signal transmission through atmospheric aerosol and fog, and deeper understanding of cloud optical properties relevant to weather and climate. In this study, we investigate the impact of light scattering in clouds on two problems of atmospheric relevance. In the first part, we examine deleterious effects of the atmosphere on remotely acquired images including signal attenuation and potential blurring due to forward-scattered light accepted by the imaging system. A prior proposed aerosol scattering model provides a method for calculating the contrast and spatial detail expected when imaging through atmospheres with significant aerosol optical depth. We compare modulation transfer functions obtained directly from images taken through a cloud chamber to those calculated from theory using measured cloud properties. We find that the significance of scattering-induced optical blurring depends sensitively on the properties of both the particles and the imaging system. The theoretical aerosol expression modulation transfer function capture the basic behavior of the system, with deviations likely a result of not accounting for broad particle size distributions. In the second part, we investigate how clusters and voids in the spatial distributions of particles within a cloud cause light transport to deviate from the exponential extinction law. We explore both perfectly random and correlated scattering media with a Monte Carlo ray tracing program, and find that the degree of non-exponential attenuation can be characterized by the radial distribution function. Our numerical observations regarding direct, diffuse and backward radiative transfer are shown to be consistent with a previous “cloudlet” approach, providing a bridge between the analytical cloudlet model and continuous correlation function approaches. Finally, we numerically explore light propagation through turbulent clouds with polydisperse size distributions calculated by a large eddy simulation of the MTU Pi Chamber. We find that both the mean and standard deviation of direct and diffuse forward flux change when clustering exists, and make suggestions for future laboratory cloud chamber experiments to detect the presence of spatial correlation

Robust Control Structure Selection

Screening tools for control structure selection in the presence of model/plant mismatch are developed in the context of the Structured Singular Value (μ) theory. The developed screening tools are designed to aid engineers in the elimination of undesirable control structure candidates for which a robustly performing controller does not exist. Through application on a multicomponent distillation column, it is demonstrated that the developed screening tools can be effective in choosing an appropriate control structure while previously existing methods such as the Condition Number Criterion can lead to erroneous results

Consumer sovereignty and entrepreneurship

Dissertation advisor: Dr. Karen A. Schnatterly.Includes vita.In this dissertation I explore the role of the consumer in the entrepreneurship process. Whereas so far entrepreneurship theory has paid cursory attention to consumers, recent research has begun to uncover an increasing role for the consumer in entrepreneurship processes, from idea generation to outcome determination. Theorists so far understand this consumer involvement as exceptional and strictly unnecessary. I challenge this view, offering a novel framework founded in the Austrian School of economics and the principle of "consumer sovereignty," which suggests that entrepreneurship is universally consumer-driven. That is, consumers are not in some cases involved in entrepreneurship. Instead, I suggest that if we trace back entrepreneurship to its very origin, we will find in each and every case an unsatisfied consumer. Here I outline a general theory of entrepreneurship built around the consumer sovereignty principle. I then explore the importance of a profound knowledge of consumer needs, in conjunction with technical knowledge, in generating valuable innovations, and test these factors in an experimental design. Finally, I revisit the new product diffusion and industry formation theories, and reconsider the role of the consumer in determining new product success. I propose that consumers' uncertainty may be the primary and driving mechanism that underpins new product diffusion, and demonstrate its theoretical viability in an agent-based model.Includes bibliographical references (pages 126-141)