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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Application of Intelligent Tires and Model Base Estimation Algorithms in Tire-road Contact Characterization

Khaleghian, Seyedmeysam 13 February 2017 (has links)
Lack of drivers knowledge about the abrupt changes in pavement friction and poor performance of the vehicle stability, traction and ABS controllers on the low friction surfaces are the most important factors affecting car crashes. Due to its direct relation to vehicle stability, accurate estimation of tire-road characteristics is of interest to all vehicle and tire companies. Many studies have been conducted in this field and researchers have used different tools and have proposed different algorithms. One such concept is the Intelligent Tire. The application of intelligent tire in tire-road characterization is investigated in this study. Three different test setups were used in this research to study the application of the intelligent tires to improve mobility; first, a wheeled ground robot was designed and built. A Fuzzy Logic algorithm was developed and validated using the robot for classifying different road surfaces such as asphalt, concrete, grass, and soil. The second test setup is a portable tire testing trailer, which is a quarter car test rig installed in a trailer and towed by a truck. The trailer was equipped with different sensors including an accelerometer attached to the center of the tire inner-liner. Using the trailer, acceleration data was collected under varying conditions and a Neural Network (NN) algorithm was developed and trained to estimate the contact patch length, effective tire rolling radius and tire normal load. The third test setup developed for this study was an instrumented Volkswagen Jetta. Different sensors were installed to measure vehicle dynamic response. Additionally, one front and one rear tire was instrumented with an accelerometer attached to their inner-liner. Two intelligent tire based algorithms, a tire pressure estimation algorithm and a road condition monitoring algorithm, were developed and trained using the experimental data from the instrumented VW Jetta. The two-step pressure monitoring algorithm uses the acceleration signal from the intelligent tire and the wheel angular velocity to monitor the tire pressure. Also, wet and dry surfaces are distinguished using the acceleration signal from the intelligent tire and the wheel angular velocity through the surface monitoring algorithm. Some of the model based tire-road friction estimation algorithms, which are widely used for tire-road friction estimation, were also introduced in this study and the performance of each algorithm was evaluated in high slip and low slip maneuvers. Finally a new friction estimation algorithm was developed, which is a combination of experiment based and vehicle dynamic based approaches and its performance was also investigated. / PHD / Lack of driver’s knowledge about the abrupt changes in pavement friction and poor performance of the vehicle stability, traction and ABS controllers on the low friction surfaces are the most important factors affecting car crashes. Due to its direct relation to vehicle stability, accurate estimation of tire-road characteristics is of interest to all vehicle and tire companies. Many studies have been conducted in this field and researchers have used different tools and have proposed different algorithms. One such concept is the Intelligent Tire. The application of intelligent tire in tire-road characterization is investigated in this study. Five main algorithms are developed in this study. First a fuzzy-logic terrain classification algorithm is developed for the small wheeled ground robot that classifies all different surfaces into four known categories; asphalt, concrete, sand and grass. A six-wheel grand robot was designed and built for this study and instrumented with intelligent tire, a tri-axial accelerometer embedded to the tire inner-liner, and other appropriate sensors. The input of the terrain classification algorithm are the intelligent tire signal, the slip ratio at the beginning of the motion and the wheel speed. The second algorithm is an intelligent tire based algorithm to estimate the tire normal load. A portable tire testing trailer, which is a quarter car test rig attached to the back of the trailer and towed by a truck was used for this part of the project. The trailer test setup was instrumented with different sensors and the tire normal load was controlled through a pneumatic force transducer and an air-spring system. A Neural Network algorithm was then trained that estimates the tire normal load using intelligent tire signal, the tire pressure and the wheel speed. The third and fourth algorithm are intelligent tire based algorithms to monitor the tire pressure and the road surface condition respectively. An instrumented vehicle, which was a Volkswagen Jetta 2003, was prepared and used for this part of the project. The inputs of these algorithms were the intelligent tire signal and the wheel speed and the outputs were the tire pressure condition and road surface condition (dry/ wet) respectively. The last algorithm is a new friction estimation algorithm, which is a combination of experiment based (intelligent tire) and vehicle dynamic based approaches. The algorithm is validated with the experimental data collected using the trailer test setup.
2

動態模型演算法在100K SNP資料之模擬研究 / Dynamic Model Based Algorithm on 100K SNP Data:A Simulation Study

黃慧珍, Hui-Chen Huang Unknown Date (has links)
研究指出,在不同人類個體的DNA序列中,只有0.1%的基因組排列是相異的,而其餘的序列則是相同的。這些相異的基因組排列則被稱為單一核苷酸(SNP)。Affymetrix公司發展出一種DNA晶片技術稱之為Affymetrix GeneChip Mapping 100K SNP set,此晶片可用來決定單一核苷酸資料的基因類型(genotype)。Affymetrix公司採用預設「動態模型演算法」(DM)來決定基因型態。本論文的研究目的是探討與示範對於DM方法中預設的S值的四種修正方式。而這四種修正的方法分別是: (1) Standardized L value,(2) Median-polished L value,(3) Median-center L value,和(4) Median-standardized L value。為了比較S值與四種改進方法,本研究藉由SNP的模擬資料來進行比較。資料的模擬是基於利用改寫過的階層式之Bolstad模型(2004),而模擬模型的參數估計是利用華人細胞株及基因資料庫中95位台灣人的100K SNP資料。根據AA模型與AB模型模擬資料的基因型態正確率,Standardized L value是最好的判斷基因型態之方法。在另一方面,因為DM方法並不是設計來決定Null模型的基因型態,因此對於Null模型模擬資料的基因型態判斷會有問題。關於Null模型的基因型態判斷,本論文提供了一些簡短的討論與建議。然而,依然需要進一步的研究探討。 / It is known there is only 0.1% in the DNA sequences that is different among human beings, and the rest of them are the same. These differences in DNA sequences are defined as SNPs (Single Nucleotide Polymorphism). The Affymetrix, Inc. had developed a DNA chip technology called Affymetrix GeneChip Mapping 100K SNP set for SNP data used to determine the genotype call. The default algorithm applied by Affymetrix, Inc. to decide genotype calls is the Dynamic Model-based (DM) algorithm. This study aimed to investigate and demonstrate four different ways to modify the basic component used in DM algorithm, namely, the S value. These four modified methods include: (1) Standardized L value, (2) Median-polished L value, (3) Median-centered L value, and (4) Median-standardized L value. In order to compare the S value with the four modified L values, a simulation study was conducted. A hierarchical version of Bolstad’s model (2004) was adopted to simulate the SNP Data. The parameters for the simulation model were estimated based on 95 Taiwanese 100K SNPs data from Taiwan Han Chinese Cell and Genome bank. The Standardized L value was proven to be the best method based on the accuracy of the genotype calls determined according to the simulated data of AA model and AB model. On the other hand, the genotype call for simulated data under Null model is problematic since the DM approach is not designed to determine the Null model. We have given some brief discussion and remarks of the genotype call for Null model. However, further research is still needed. /

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