Bruce Wilson - US grants

9410144 Wilson In this project, an analytical modeling methodology and automated modeling tool is developed for electromechanical systems. The methodology acknowledges and incorporates the inherent uncertainty involved in models. The tool accepts a component- based description of an electromechanical systems as input. These component descriptions, including tolerances, are mapped in to models whose perameters have tolerances, uncertainty bounds are determined for both component and system models, and optimal order of system models in determined. In conventional models, component dimensions and material constants are approximate, whereas model coefficients are assumed constant. ***

9512472 Parker This Academic Research Infrastructure grant provides $250,000 as one-half support of the development of an experimental facility for the study of large scale river morphology, stratigraphy and landscape evolution. The facility will be constructed at the St. Anthony Falls Hydraulic Laboratory, University of Minnesota in an existing indoor basin that is 14.3 m long and 7.3 m wide. The main elements of the basin will include, a rainmaker for simulating various hydrologic regimes, a hinged floor to simulate tectonic uplift and subsidence, a zone of ponded water and feed points for water and sediment along the basin. All elements of the basin are to be computer controlled and monitored by a data acquisition system. The main subsystems of the data acquisition system will be two computer controlled laser profilers for precision measurements of microrelief, a particle imaging velocimetry system for instantaneous measurement of surface flow velocities, an optical imaging system for instantaneous determination of channel depth and a stereoimaging system for determination of overall topography. This project is to be constructed and utilized by an interdisciplinary team consisting of a civil engineer, a sedimentologist, an environmental engineer, an agricultural engineer and an engineer with considerable knowledge of electronics. The basin is to be operable in both subaerial and subaqueous mode allowing for studies of both riverine processes and terrestrial landscape evolution and studies of continental shelf, slope and rise evolution. An automated mesocosm of this kind allows for the control of governing variables and monitoring on time and spatial scales that are not easily observed in field situations. This facility should provide a bridge between simulation and field research that hastens the development of new predictive tools and it is intended that the facility be made available to a broad spectrum of outside researchers. ***

This GOALI award is to support a two-month collaborative research effort of UPI at Barry Controls of Brighton, MA. During the first four weeks of research, the PI will review vibration isolation system control strategies; formulate realistic controller and actuator models; and carry out robust stability analysis. The analysis will demonstrate the utility of a new analysis technique developed by the PI to solve a real world problem. During the next five weeks, the research will focus on power and energy consumption of an active vibration isolation system. Power requirements with a variety of controllers for both conventional and regenerative control strategy, it will be possible to quantify required power versus the performance of the closed- loop system, which is critical for system design. For the regenerative control strategy, the product of actuator force and actuator velocity, when positive--denotes the power required by the vibration isolation system; and when negative-denotes the power to be applied to the system, i.e., power that could actually be regenerated. A major goal of this research is to enhance an understanding of regenerative control as applied to vibration isolation systems.

Cate Brinson, Michael Peshkin, Bruce Wilson
Northwestern University

Shape memory alloys (SMAs) have been used in a variety of actuation, energy-absorbing, and sensing applications. The key feature of this material is its ability to undergo large seemingly-plastic strains and subsequently recover these strains when a load is removed or the material is heated. This unique ability occurs due to a reversible thermoelastic phase transformation between austenite and martensite. The key feature allows SMAs to serve as very compact actuators. As SMAs can be used for both material-stiffening and energy-absorption, they have generated much interest in the smart structures field. Further, no other material or device can generate significant tensile forces over a large displacement while occupying such a small volume. A second useful feature of many SMAs is a change in resistivity with a change in strain. The change in resistivity as an SMA undergoes strain has enabled investigators to use them as coarse position sensors. The coarseness is due to a complex relationship between resistivity and the material state and its coupling with mechanical load and temperature.

Given the material characteristics above, economical, power-dense self-sensing-actuation (SSA) can be achieved with shape memory alloys. However, the nonlinear nature of SMA actuation and sensing, incomplete understanding of SMA thermomechanical response and the lack of suitable models for control result in an under-utilization of this useful material as an actuator, sensor, and SSA. In this research, a focused effort will be targeted at (1) improving the characterization of SMAs for a sensing and control context, (2) refining material modeling, (3) developing model-based control algorithms, and (4) demonstrating these in hardware to advance the understanding and range of applications of SMAs as actuators, sensors, and SSAs.

This project provides scholarships to able and financially needy students majoring in Biology, Chemistry, Earth Science, Mathematics, and Physics. The project emphasizes enrichment opportunities that concentrate on engaged learning activities that are best suited to the students' studies and aspirations. These include faculty mentoring, monthly project participant meetings, and optional engaged learning experiences that include faculty guided or independent research, internships, and field trips to local industries. Other engagement activities involve participation in professional organizations, including attending and presenting at conferences.

Intellectual Merit: The academic programs into which the students go are strong, and there are academic support activities. The project focuses on student engagement and faculty mentorship in the context of an interdisciplinary community of scholars. This approach is designed to strengthen undergraduate science and mathematics education, increase retention and persistence to graduation, and better prepare students for professional careers where the boundaries between academic disciplines are not clearly drawn.

Broader Impact: The project is increasing the number and diversity of students who complete a STEM major and go on to work in the field or to further education. Many of the interdisciplinary activities are made available to all UVU STEM students, during and after the funding period. Moreover, the goal of graduating more and better-prepared students in mathematics and the sciences is not only an institutional goal, but a community and state goal as well. As such, the college is building partnerships with business organizations to offer internships and on-site learning experiences that take the classroom and laboratory education out to the real world. This facilitates job placement for students as well as enhances the university's relationship with local industry.