The goal of this thesis is to design the steering vehicle system by joystick. The main function of the steering vehicle system is drivers can operate the joystick with electrical control to accomplish steering motion. In this paper , the main design framework of the steering vehicle system is divided into three stages of the experiment, vehicle architecture, vehicle dynamic simulation and vehicle test results . The overall system is modified Go-kart as a platform, develop a suitable joystick framework in the vehicle, and apply the encoder on the joystick, which transfer the control information into the position signal, to be the input command of steering motor control program. According to the steering by wire for brushless DC servo motor control strategy, the system control architecture achieve the goal by embedded-DSP. And to test double-lane change by Go-kart. Experimental results recorded by gyroscope can compare the steering situation of joystick with steering wheel.

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In this research, an autonomous vehicle function management methodology is studied. In accordance with the traffic situation, the decision making level chooses the optimal function that guarantees safety and minimizes fuel consumption while the control level is implemented via neuromorphic strategy based on the brain limbic system. To realize the decision making strategy, the Analytic Hierarchy Process (AHP) is used by considering driving safety, driving speed, and fuel efficiency as the objectives. According to the traffic situation and predefined driving mode, Lane Change Maneuver (LCM) and Adaptive Cruise Control (ACC) are chosen as the alternative functions in the AHP framework. The adaptive AHP is utilized to cope with dynamically changing traffic environment. The proposed adaptive AHP algorithm provides an optimal relative importance matrix that is essential to make decisions under a varying traffic situation and driving modes. The simulation results show that proposed autonomous vehicle function management structure produces optimal decisions that satisfy the driving preference. The stability of BLS based control is also investigated via Cell-to-Cell Mapping. In this research, autonomous vehicle functions such as Lane change maneuver and Adaptive cruise control are developed by means of BLS based control. The simulation results considered various traffic situations that an autonomous vehicle can encounter. To demonstrate the suggested control method Cell-to-Cell Mapping is utilized. Subsequently, the autonomous vehicle function management strategy is developed by Applying AHP and an adaptive AHP strategy is developed to cope with various traffic situations and driving modes. The suggested method is verified numerical simulations.

The research in this thesis was conducted to investigate the initial stage of passing maneuvers on a rural, two-lane, two-way (RTLTW) highway with centerline rumble strips (CRSs). Four measures of effectiveness were used: (1) number and type of erratic movements by a passing vehicle, (2) number of and time between centerline encroachments of a passing vehicle, (3) gap distance of a passing vehicle, and (4) centerline crossing time. Data were collected for a before-and-after analysis at one site, in Comanche County, Texas. The test section was on US 67 from Comanche, Texas to the county line south of Dublin, Texas. The posted speed limit for this RTLTW highway was 70 mph during the day. CRSs were installed along approximately 15 miles of US 67. Only one test design for CRSs was installed. The design specification was for a CRS to be milled to a 0.5-inch depth, 7-inch length, and 16-inch width. This specification was developed from current state practices throughout the United States. CRSs were installed continuously through passing and no-passing zones, and they were spaced at 24 inches on-centers. Pavement markings were striped over the CRSs. Data were collected using an innovative data collection system developed by the author through the Texas Transportation Institute (TTI). This system was mounted to a four-door sedan, and it consisted of four concealed cameras that recorded the entire passing maneuver around the data collection vehicle. Data were collected at three different speeds during the daytime. The speeds were 55, 60, and 65 mph (15, 10, and 5 mph, respectively, under the posted speed limit). Based on the assessment of the four MOEs, the overall finding of this thesis was that driver performance during the initial phase of passing maneuvers was not negatively impacted after the installation of CRSs on US 67. The caveat is that differences in the weather conditions may have influenced the results. The weather was dry with clear skies at the study site during data collection prior to the installation of CRSs; however, the weather consisted of intermittent rain during the data collection after the installation of CRSs.

published_or_final_version / Architecture / Master / Master of Architecture

Vehicle navigation systems incorporate on-board sensors/signal receivers and provide necessary positioning and guidance information for land, marine, airborne and space vehicles. Among different navigation solutions, the Global Positioning System (GPS) and an Inertial Navigation System (INS) are two basic navigation systems. Due to their complementary characters in many aspects, a GPS/INS integrated navigation system has been a hot research topic in recent decades. Both advantages and disadvantages of each individual system and their combination are analysed in this thesis. The Micro Electrical Mechanical Sensors (MEMS) successfully solved the problems of price, size and weight with traditional INS, and hence are widely applied in GPS/INS integrated systems. The main problem of MEMS is the large sensor errors, which rapidly degrade the navigation performance in an exponential speed. By means of different methods, such as autoregressive model, Gauss-Markov process, Power Spectral Density and Allan Variance, we analyse the stochastic errors within the MEMS sensors. The test results show that different methods give similar estimates of stochastic error sources. An equivalent model of coloured noise components (random walk, bias instability and ramp noise) is given. Three levels of GPS/IMU integration structures, i.e. loose, tight and ultra-tight GPS/IMU navigation, are introduced with a brief analysis of each character. The loose integration principles are presented with detailed equations as well as the INS navigation principles. The Extended Kalman Filter (EKF) is introduced as the data fusion algorithm, which is the core of the whole navigation system. Based on the system model, we show the propagation of position standard errors with the tight integration structure under different scenarios. Even less than 4 observable GNSS satellites can contribute to the integrated system, especially for the orientation errors. A real test with loose integration is carried out, and the EKF performance is analysed in detail. Since the GPS receivers are normally working with a digital map, the map matching principle and its link-choosing problem are briefly introduced. This problem is proposed to be solved by the lane detection from real-time images. The procedures for the lane detection based on image processing are presented. The test on high ways, city streets and pathways are successfully carried out, and analyses with possible solutions are given for some special failure situations. To solve the large error drift of the IMU, we propose to support the IMU orientation with camera motion estimation from image pairs. First the estimation theory and computer vision principles are briefly introduced. Then both point and line matches algorithms are given. Finally the L1-norm estimator with balanced adjustment is proposed to deal with possible mismatches (outliers). Tests and comparisons with the RANSAC algorithm are also presented. For the latest trend of MEMS chip sensors, their industry and market are introduced. To evaluate the MEMS navigation performance, we augment the EKF with an equivalent coloured noise model, and the basic observability analysis is given. A realistic simulated navigation test is carried out with single and multiple MEMS sensors, and a sensor array of 5-10 sensors are recommended according to the test results and analysis. Finally some suggestions for future research are proposed. / <p>QC 20131016</p>

One of the significant weaknesses of the design speed concept is that it uses the design speed of the most restrictive geometric element as the design speed of the entire road. This leads to potential inconsistencies among successive sections of a road. Previous studies documented that a uniform design speed does not guarantee consistency on rural two-lane facilities. It is therefore reasonable to assume that similar inconsistencies could be found on rural four-lane non-freeway highways. The operating speed-based method is popularly used in other countries for examining design consistency. Numerous studies have been completed on rural two-lane highways for predicting operating speeds. However, little is known for rural four-lane non-freeway highways. This study aims to develop operating speed prediction models for horizontal curves on rural four-lane non-freeway highways using 74 horizontal curves. The data analysis showed that the operating speeds in each direction of travel had no statistical differences. However, the operating speeds on inside and outside lanes were significantly different. On each of the two lanes, the operating speeds at the beginning, middle, and ending points of the curve were statistically the same. The relationships between operating speed and design speed for inside and outside lanes were different. For the inside lane, the operating speed was statistically equal to the design speed. By contrary, for the outside lane, the operating speed was significantly lower than the design speed. However, the relationships between operating speed and posted speed limit for both inside and outside lanes were similar. It was found that the operating speed was higher than the posted speed limit. Two models were developed for predicting operating speed, since the operating speeds on inside and outside lanes were different. For the inside lane, the significant factors are: shoulder type, median type, pavement type, approaching section grade, and curve length. For the outside lane, the factors included shoulder type, median type, approaching section grade, curve length, curve radius and presence of approaching curve. These factors indicate that the curve itself does mainly influence the drivers speed choice.

Driving simulators and microscopic traffic simulation are important tools for making evaluations of driving and traffic. A driving simulator is de-signed to imitate real driving and is used to conduct experiments on driver behavior. Traffic simulation is commonly used to evaluate the quality of service of different infrastructure designs. This thesis considers a different application of traffic simulation, namely the simulation of surrounding vehicles in driving simulators. The surrounding traffic is one of several factors that influence a driver's mental load and ability to drive a vehicle. The representation of the surrounding vehicles in a driving simulator plays an important role in the striving to create an illusion of real driving. If the illusion of real driving is not good enough, there is an risk that drivers will behave differently than in real world driving, implying that the results and conclusions reached from simulations may not be transferable to real driving. This thesis has two main objectives. The first objective is to develop a model for generating and simulating autonomous surrounding vehicles in a driving simulator. The approach used by the model developed is to only simulate the closest area of the driving simulator vehicle. This area is divided into one inner region and two outer regions. Vehicles in the inner region are simulated according to a microscopic model which includes sub-models for driving behavior, while vehicles in the outer regions are updated according to a less time-consuming mesoscopic model. The second objective is to develop an algorithm for combining autonomous vehicles and controlled events. Driving simulators are often used to study situations that rarely occur in the real traffic system. In order to create the same situations for each subject, the behavior of the surrounding vehicles has traditionally been strictly controlled. This often leads to less realistic surrounding traffic. The algorithm developed makes it possible to use autonomous traffic between the predefined controlled situations, and thereby get both realistic traffc and controlled events. The model and the algorithm developed have been implemented and tested in the VTI driving simulator with promising results.

The purpose of this study was to gain a clearer picture of how after-school-care teachers’ work with fundamental values in after-school care, both practically and theoretically based on the curriculum Lgr 11. I wanted to acquire a broader understanding of the school's core values and what kinds of tools teachers used to cope with their task. I proceeded with two questions: How does after-school care proactively work with core values based on gender, ethnicity and class? How does the work on value issues at after-school care centers compare with Lgr 11? In my study, I used literature studies and a qualitative analysis of five interviews with afterschool care teachers. I came to the conclusion that the fundamental values were difficult to interpret and that the majority of the interviewed after-school care teachers adapted the core values after the schools "needs". Keywords: values, after-school care, standards, development and learning / Syftet med den här undersökningen var att få en tydligare bild över hur fritidspedagoger arbetar med värdegrundsarbetet, både praktiskt och teoretiskt utifrån läroplanen Lgr 11. Jag ville införskaffa en bredare förståelse om skolans värdegrund och vilka verktyg som används av pedagogerna för att klara av uppgiften. Jag utgick från två frågeställningar i arbetet: Hur arbetar fritidshemen i förebyggande syfte med värdegrundsfrågor utifrån genus, etnicitet och klass? Hur förhåller sig arbetet med värdegrundsfrågor på fritidshemmen i förhållande med Lgr 11. För att få fram mitt resultat använde jag mig av litteratur och att intervjua fem fritidspedagoger. Jag kom fram till att värdegrundsarbetet är svårtolkat och att många av de intervjuade fritidspedagogerna anpassade värdegrunden ut efter skolans ”behov”. Bakgrunden till min studie uppkom under min sista VFU period då jag såg ett behov av värdegrundsarbete i en elevgrupp där jag fann vissa motsättningar. Efter eget initiativ till övningar med dessa elever insåg jag hur eleverna var mottagliga och hur de inblandade utvecklats med hjälp av värdegrundsövningarna. Det var så jag såg hur viktigt värdegrundsarbete i skolan är. Nyckelord: värdegrund, fritidshem, normer, utveckling och lärande

No abstract available