Matching Items (2)
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Description
This study exmaines the effect of in-vehicle infotainment display depth on driving performance. More features are being built into infotainment displays, allowing drivers to complete a greater number of secondary tasks while driving. However, the complexity of completing these tasks can take attention away from the primary task of driving,

This study exmaines the effect of in-vehicle infotainment display depth on driving performance. More features are being built into infotainment displays, allowing drivers to complete a greater number of secondary tasks while driving. However, the complexity of completing these tasks can take attention away from the primary task of driving, which may present safety risks. Tasks become more time consuming as the items drivers wish to select are buried deeper in a menu’s structure. Therefore, this study aims to examine how deeper display structures impact driving performance compared to more shallow structures.

Procedure. Participants complete a lead car following task, where they follow a lead car and attempt to maintain a time headway (TH) of 2 seconds behind the lead car at all times, while avoiding any collisions. Participants experience five conditions where they are given tasks to complete with an in-vehicle infotainment system. There are five conditions, each involving one of five displays with different structures: one-layer vertical, one-layer horizontal, two-layer vertical, two-layer horizontal, and three-layer. Brake Reaction Time (BRT), Mean Time Headway (MTH), Time Headway Variability (THV), and Time to Task Completion (TTC) are measured for each of the five conditions.

Results. There is a significant difference in MTH, THV, and TTC for the three-layer condition. There is a significant difference in BRT for the two-layer horizontal condition. There is a significant difference between one- and two-layer displays for all variables, BRT, MTH, THV, and TTC. There is also a significant difference between one- and three-layer displays for TTC.

Conclusions. Deeper displays negatively impact driving performance and make tasks more time consuming to complete while driving. One-layer displays appear to be optimal, although they may not be practical for in-vehicle displays.
ContributorsGran, Emily (Author) / Gray, Robert (Thesis advisor) / Branaghan, Russell (Committee member) / Carrasquilla, Christina (Committee member) / Arizona State University (Publisher)
Created2018
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Description
Presently, hard-switching buck/boost converters are dominantly used for automotive applications. Automotive applications have stringent system requirements for dc-dc converters, such as wide input voltage range and limited EMI noise emission. High switching frequency of the dc-dc converters is much desired in automotive applications for avoiding AM band interference and for

Presently, hard-switching buck/boost converters are dominantly used for automotive applications. Automotive applications have stringent system requirements for dc-dc converters, such as wide input voltage range and limited EMI noise emission. High switching frequency of the dc-dc converters is much desired in automotive applications for avoiding AM band interference and for compact size. However, hard switching buck converter is not suitable at high frequency operation because of its low efficiency. In addition, buck converter has high EMI noise due to its hard-switching. Therefore, soft-switching topologies are considered in this thesis work to improve the performance of the dc-dc converters.

Many soft-switching topologies are reviewed but none of them is well suited for the given automotive applications. Two soft-switching PWM converters are proposed in this work. For low power automotive POL applications, a new active-clamp buck converter is proposed. Comprehensive analysis of this converter is presented. A 2.2 MHz, 25 W active-clamp buck converter prototype with Si MOSFETs was designed and built. The experimental results verify the operation of the converter. For 12 V to 5 V conversion, the Si based prototype achieves a peak efficiency of 89.7%. To further improve the efficiency, GaN FETs are used and an optimized SR turn-off delay is employed. Then, a peak efficiency of 93.22% is achieved. The EMI test result shows significantly improved EMI performance of the proposed active-clamp buck converter. Last, large- and small-signal models of the proposed converter are derived and verified by simulation.

For automotive dual voltage system, a new bidirectional zero-voltage-transition (ZVT) converter with coupled-inductor is proposed in this work. With the coupled-inductor, the current to realize zero-voltage-switching (ZVS) of main switches is much reduced and the core loss is minimized. Detailed analysis and design considerations for the proposed converter are presented. A 1 MHz, 250 W prototype is designed and constructed. The experimental results verify the operation. Peak efficiencies of 93.98% and 92.99% are achieved in buck mode and boost mode, respectively. Significant efficiency improvement is achieved from the efficiency comparison between the hard-switching buck converter and the proposed ZVT converter with coupled-inductor.
ContributorsNan, Chenhao (Author) / Ayyanar, Raja (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Karady, George G. (Committee member) / Qin, Jiangchao (Committee member) / Arizona State University (Publisher)
Created2016