Jadhav, Saurabh Subhash. (2017). Virtual Reality based User Interface for Conceptual Design and Rapid Prototyping. UC San Diego: Engineering Sciences (Mechanical Engineering). Retrieved from: http://www.escholarship.org/uc/item/5pq3j64x
Mechanical engineering, 3D User Interface, Computer Aided Design, Finite Element Analysis, Product Developement, Virtual Reality, and Virtual Reality Aided Design
Computer Aided Design and Engineering (CAD/ CAE) tools currently available in the market have dramatically improved since their inception. In product development, CAD/ CAE has enabled the user to design, test, analyze and optimize the product virtually even before the first prototype is built. Use of direct modeling for product conceptualization allows the designer to create concept design iterations freely, quickly, flexibly and fast optimization. While modeling geometric databases have been 3D since long time, the interaction technology still uses 2D input devices like mouse, with Virtual Reality (VR) as a standalone visualization tool. Over the years, it has been recognized that the conventional 2D input devices for entering 3D shape information makes the interaction cumbersome and negatively affect creativity. This research focuses on design of virtual reality based user interface for automotive chassis designVirtual reality based user interface is developed to iteratively design and prototype various automotive chassis concepts. The tools for ergonomic analysis and center of mass visualization enable the user to rapidly optimize the design in VR. The VR environment is interfaced with commercial finite element software to test the design concepts for structural integrity. Virtual constrains aid modeling tasks and minimize the processing effort required on the conceptual model to a parametric model.The thesis is concluded with a preliminary cognitive walkthrough study. The VR based user interface can allow the user to rapidly test various design concepts quickly, and flexibly. The user interface can reduce the concept to market time, enhance creativity, and reduce the total cost of product development. This interface can be a stepping stone for the future VR based CAD interfaces.
Kopek, Derek; McLeod, Brian; McCracken, Kenneth; van Dam, Marcos; Bouchez, Antonin; Conder, Alan; et al.(2015). Prototyping the GMT phasing camera with the Magellan AO system. Adaptive Optics for Extremely Large Telescopes 4 – Conference Proceedings, 1(1). doi: 10.20353/K3T4CP1131566. Retrieved from: http://www.escholarship.org/uc/item/81f1f8pt
Active optics, adaptive optics, Giant Magellan Telescope, phasing, and dispersed fringe sensor
The future diffraction-limited performance of the 25.4 meter Giant Magellan Telescope (GMT) will rely on the activeand adaptive wavefront sensing measurements made by the Acquisition, Guiding, and Wavefront Sensor (AGWS)currently being designed by SAO. One subsystem of the AGWS, the phasing camera, will be responsible for measuringthe piston phase difference between the seven GMT primary/secondary segment pairs to 50 nm accuracy with full skycoverage using natural guide stars that are 6-10 arcmin off-axis while the on-axis light is used for science operations.The phasing camera will use a dispersed fringe sensor to measure the phase difference in rectangular subaperturesspanning the gaps between adjacent mirror segments. The large gap between segments (>295 mm, compared to 3 mmfor the Keck telescope) reduces the coherence of light across the subapertures, making this problem particularlychallenging. In support of the AGWS phasing camera technical goals, SAO has undertaken a series of prototypingefforts at the Magellan 6.5 meter Clay telescope to demonstrate the dispersed fringe sensor technology and validateatmospheric models. Our latest on-sky test, completed in December 2015, employs a dual-band (I and J) dispersedfringe sensor. This prototype uses an adaptive optics corrected beam from the Magellan AO adaptive secondary system.The system operates both on-axis and 6 arcmin off-axis from the natural guide star feeding the MagAO wavefrontsensor. This on-sky data will inform the development of the AGWS phasing camera design towards the GMT first light.
Chung, P, Heller, JA, Etemadi, M, Ottoson, PE, Liu, JA, Rand, L, and Roy, S
Chung, P; Heller, JA; Etemadi, M; Ottoson, PE; Liu, JA; Rand, L; et al.(2014). Rapid and low-cost prototyping of medical devices using 3D printed molds for liquid injection molding. Journal of Visualized Experiments, (88). doi: 10.3791/51745. UC San Francisco: Retrieved from: http://www.escholarship.org/uc/item/8p68462x
Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications.
Sherman, Christopher Timothy. (2014). Modeling, Design, and Prototyping of a MEMS Piezoelectric Permanent Magnet Current Sensor with Vibration-Canceling. UC Berkeley: Mechanical Engineering. Retrieved from: http://www.escholarship.org/uc/item/9kc762vq
Mechanical engineering, Design, MEMS, piezoelectricity, and smartgrid
As the electric power grid incorporates an increasing number of renewable energy sources and large, variable loads, better electricity monitoring at increased resolution becomes essential. Simultaneously, the rise of wireless sensor nodes, a.k.a. "motes," has made larges-cale, low-power data collection increasingly-feasible. The existing technologies for AC current sensing, however, are less than optimally-suited for this sort of application; current transformers are large and bulky, and most proximity-based magnetic field sensors consume too much power for extended operation on batteries. In the work that follows, we will explore the modeling, design, prototyping, and testing of a new, novel type of proximity-based current sensor that is both small and ultra-low-power.By using a pair of interconnected piezoelectric cantilevers with permanent magnets mounted on their free ends, it is possible to sense AC current by proximity while simultaneously rejecting ambient mechanical vibrations. Starting from an analytic system-as-a-circuit model, a design strategy is implemented using dynamic range as a primary figure of merit to develop an aluminum nitride, MEMS-based candidate sensor. Primary production of this candidate design is completed by MEMSCAP Inc, and final assembly and integration of the designs is completed at UC Berkeley.Using the 11 mm-long MEMSCAP-produced aluminum nitride dies and two 750-micron magnets, a dual-cantilever current sensor with a sensitivity of 6.41 mV per gauss has been produced. Due to non-idealities in fabrication, this output voltage is less than originally modeled but still close to the design target of 7 mV per gauss . The vibration-cancellation technique functions as-intended for frequencies below 150 Hz or above 185 Hz. Proof of concept testing of this technique is demonstrated for 1-35 A of 60 Hz AC current with the sensor in proximity to a vibrating motor generating 50 mG of 120 Hz sinusoidal acceleration.
Helu, Moneer, Noble, Joanna, McKinstry, Katherine, Hoople, Gordon, Rolfe, David, Berthold, Dennis, Ninomiya, Kevin, and Dornfeld, David
Helu, Moneer; Noble, Joanna; McKinstry, Katherine; Hoople, Gordon; Rolfe, David; Berthold, Dennis; et al.(2013). Quantifying the Improvements in Rapid Prototyping and Product Life Cycle Performance Created by Machining. Proceedings of the MTTRF 2013 Annual Meeting. UC Berkeley: Laboratory for Manufacturing and Sustainability. Retrieved from: http://www.escholarship.org/uc/item/5fj0343s