5 research outputs found
Recommended from our members
Geometric modeling and electromagnetic analysis of electrical windings for pulsed alternators
Pulsed alternators are state-of-the-art machines that require analytical design tools with a high level of fidelity. To meet the design needs, accurate modeling and analysis methods of the electrical windings of the machines have had to be developed. This paper will present a technique for creating accurate geometric models of racetrack style electrical windings, as well as a means of using these models to perform electromagnetic load analysis of the windings. This will begin with discussion of how one would convert a two-dimensional developed layout of a racetrack style winding into a full three-dimensional model. Using a similar technique, a model can be created for use in an electromagnetic (EM) analysis package. The results from this analysis can then be used to apply the resulting loads back onto the geometric model for mechanical analysis.Center for Electromechanic
Recommended from our members
Kinematic optimization of upgrade to the Hobby Eberly Telescope through novel use of commercially available three dimensional CAD package
The University of Texas, Center for Electromechanics (UT-CEM) is making a major upgrade to the robotic tracking system on the Hobby Eberly Telescope (HET) as part of the Wide Field Upgrade (WFU). The upgrade focuses on a seven-fold increase in payload and necessitated a complete redesign of all tracker supporting structure and motion control systems, including the tracker bridge, ten drive systems, carriage frames, a hexapod, and many other subsystems. The cost and sensitivity of the scientific payload, coupled with the tracker system mass increase, necessitated major upgrades to personnel and hardware safety systems. To optimize kinematic design of the entire tracker, UT-CEM developed novel uses of constraints and drivers to interface with a commercially available CAD package (SolidWorks). For example, to optimize volume usage and minimize obscuration, the CAD software was exercised to accurately determine tracker/hexapod operational space needed to meet science requirements. To verify hexapod controller models, actuator travel requirements were graphically measured and compared to well defined equations of motion for Stewart platforms. To ensure critical hardware safety during various failure modes, UT-CEM engineers developed Visual Basic drivers to interface with the CAD software and quickly tabulate distance measurements between critical pieces of optical hardware and adjacent components for thousands of possible hexapod configurations. These advances and techniques, applicable to any challenging robotic system design, are documented and describe new ways to use commercially available software tools to more clearly define hardware requirements and help insure safe operation.Center for Electromechanic
Recommended from our members
Magnetic gears – an essential enabler for the next generation’s electromechanical drives
New magnetic gears show promise as replacements for mechanical gears, not only because of high reliability and low maintenance, but also because of superior torque-to-weight ratios. A superior torqueto- weight ratio is most unexpected but is surfacing as a real possibility when the full perimeter of the gear is used to generate torque. Mechanical gears are to be distinguished in this one aspect since only two to three teeth are engaged in a single stage. For this same reason, high gear ratio magnetic gears can be constructed without the use of multiple stages.Center for Electromechanic
Recommended from our members
Test Methods for Composite Structures for Pulsed Power, Rotating Machines
Composites are an enabling technology for achieving high power and energy densities in pulsed power rotating machinery. Due to extreme thermomechanical loads, an optimized combination of structural, thermal, and electrical properties is required to achieve the desired durability and service life performance. Coupon level tests are performed to generate the results necessary to quantify these properties and guide the development of a correctly balanced composite. This paper presents a top-level discussion of test methodologies and their use that are important for evaluation of composite laminate properties for pulsed power applications. Test methodologies include: (1) hydroburst for hoop (circumferential) properties; (2) transverse tensile and shear tests for resin dominated loading; (3) radial precompression testing for viscoelastic effects; (4) fiber digestion for fiber volume and void content determination, digital photomicrographs for visual evaluation; and (5) transverse electrical conductivity tests. Both the hydroburst and transverse tensile test fixtures feature elevated temperature test capabilities. These test techniques, which are currently in use at The University of Texas at Austin Center for Electromechanics (UT-CEM), are described and typical test-generated data is discussed.Center for Electromechanic
Recommended from our members
Testing, characterization, and control of a multi-axis high precision drive system for the Hobby-Eberle Telescope Wide Field Upgrade
A multi-axis, high precision drive system has been designed and developed for the Wide Field Upgrade to the Hobby-Eberly Telescope at McDonald Observatory. Design, performance and controls details will be of interest to designers of large scale, high precision robotic motion devices. The drive system positions the 20-ton star tracker to a precision of less than 5 microns along each axis and is capable of 4 meters of X/Y travel, 0.3 meters of hexapod actuator travel, and 46 degrees of rho rotation. The positioning accuracy of the new drive system is achieved through the use of high-precision drive hardware in addition to a meticulously tuned high-precision controller. A comprehensive understanding of the drive structure, disturbances, and drive behavior was necessary to develop the high-precision controller. Thorough testing has characterized manufacture defects, structural deflections, sensor error, and other parametric uncertainty. Positioning control through predictive algorithms that analytically compensate for measured disturbances has been developed as a result of drive testing and characterization. The drive structure and drive dynamics are described as well as key results discovered from testing and modeling. Controller techniques and development of the predictive algorithms are discussed. Performance results are included, illustrating recent performance of several axes of the drive system. This paper describes testing that occurred at the Center for Electromechanics in Austin Texas.Center for Electromechanic