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Articles 1 - 6 of 6
Full-Text Articles in Mechanical Engineering
Ortho-Planar Linear-Motion Springs, John J. Parise, Larry L. Howell, Spencer P. Magleby
Ortho-Planar Linear-Motion Springs, John J. Parise, Larry L. Howell, Spencer P. Magleby
Faculty Publications
This paper presents an ortho-planar spring design that operates by raising or lowering its platform relative to the base with no rotation. The compact nature of the design, and its non-rotating motion, eliminates the problem of rotation against adjoining surfaces and is less sensitive to variation in assemblies than many current compact springs. Nomenclature is presented to identify different configurations, mathematical equations are provided that accurately model the force-defection relationships, and a pneumatic valve positioner application is demonstrated.
Spline Based Path Planning For Unmanned Air Vehicles, Kevin B. Judd, Timothy W. Mclain
Spline Based Path Planning For Unmanned Air Vehicles, Kevin B. Judd, Timothy W. Mclain
Faculty Publications
A trajectory planning scheme that generates feasible flight routes for an unmanned air vehicle (UAV) is developed. A preliminary path is generated from a Voronoi diagram based on threat locations. This path consists of a series of straight-line segments that cannot be followed exactly by the UAV. Using a series of cubic splines to connect these straight-line segments, this path is refined into an optimum path that is flyable by the UAV. Utilizing a decomposition strategy, both the full path (coarse detail) to the target and the proximate optimum path (fine detail) near the UAV can be quickly computed. The …
Predicting The Effects Of Dimensional And Material Property Variations In Micro Compliant Mechanisms, Jonathan W. Wittwer
Predicting The Effects Of Dimensional And Material Property Variations In Micro Compliant Mechanisms, Jonathan W. Wittwer
Theses and Dissertations
Surface micromachining of micro-electro-mechanical systems (MEMS), like all other fabrication processes, has inherent variation that leads to uncertain material and dimensional parameters. To obtain accurate and reliable predictions of mechanism behavior, the effects of these variations need to be analyzed. This thesis expands already existing tolerance and uncertainty analysis methods to apply to micro compliant mechanisms. For simple compliant members, explicit equations can be used in uncertainty analysis. However, for a nonlinear implicit system of equations, the direct linearization method may be used to obtain sensitivities of output parameters to small changes in known variables. This is done by including …
Fuel-Saving Strategies For Dual Spacecraft Interferometry Missions, Christopher A. Bailey, Timothy W. Mclain, Randal W. Beard
Fuel-Saving Strategies For Dual Spacecraft Interferometry Missions, Christopher A. Bailey, Timothy W. Mclain, Randal W. Beard
Faculty Publications
Separated spacecraft interferometry missions will require that spacecraft move in a coordinated fashion to ensure minimal and balanced consumption of fuel. This paper develops strategies for determining interferometry mission plans that result in significant fuel savings over standard approaches. Simulation results demonstrate that valuable reductions in fuel consumption can be realized by combining the retargeting and imaging maneuvers required to image multiple stellar sources. Fuel-optimal imaging strategies have been developed for two-spacecraft interferometry missions similar to the proposed StarLight mission using chained local optimization methods. Based on these strategies, sampling-pattern guidelines for space-borne interferometry missions have been developed.
Cooperative Control Of Uav Rendezvous, Timothy W. Mclain, Phillip R. Chandler, Steven Rasmussen, Meir Pachter
Cooperative Control Of Uav Rendezvous, Timothy W. Mclain, Phillip R. Chandler, Steven Rasmussen, Meir Pachter
Faculty Publications
The cooperative control of timing and synchronization of tasks of multiple unmanned air vehicles (UAVs) represents a valuable capability for a wide range of potential multi-UAV missions. This research addresses the specific problem of cooperative rendezvous in which multiple UAVs are to arrive at their targets simultaneously. The development of a rendezvous manager state machine and a cooperative control decomposition approach are described. Simulation results demonstrating the feasibility of the approach are presented.
Microstructure-Sensitive Design Of A Compliant Beam, Brent L. Adams, Alisa J. Millar Henrie, B. Henrie, M. Lyon, H. Garmestani, Surya R. Kalidindi
Microstructure-Sensitive Design Of A Compliant Beam, Brent L. Adams, Alisa J. Millar Henrie, B. Henrie, M. Lyon, H. Garmestani, Surya R. Kalidindi
Faculty Publications
BA acknowledges financial support provided by the MRSEC Program of the National Science Foundation under Award Number DMR-9632556. SK acknowledges financial support from National Science Foundation under Award Number CMS-9732699. BA, SK and HG also acknowledge support from the NSF-CIRE program centered at Florida A&M University, facilitating collaborations. Support was also provided by the College of Engineering and Technology at BYU (AH, BH and ML). Computations were performed on the new SGI Origin 2000 supercomputer at Brigham Young University, donated by Ira Fulton. We show that mechanical design can be conducted where consideration of polycrystalline microstructure as a continuous design …