• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.43-48
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• 2011

The air blowers for fuel cell electric vehicle usually have big difference between inlet and outlet pressure. When the casing of the air blowers is designed, the stress analysis is required. (Approximately Inlet pressure is 0.5bar and outlet pressure is 2bar.) Gap distance between the casing and the impeller is 0.3mm. Therefore, if the amount of maximum deformation of casing is larger than 0.3mm, impeller crashed the casing. In order to avoid crashing, both the thickness and number of rims are changed and carried out simulations on each cases.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.3
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• pp.28-34
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• 2004

This paper presents the results of the structural analysis and optimal design of the ROV to be operated at 6000m depth in the ocean. This will be the first domestic deep-sea ROV operating with an AUV and a launcher equipped with robot arms and the current weight is about 3 ton. initial optimal dimension of the frame is determined based on the stress analysis using FEA code ANSYS and design sensitivity and optimization results. The current design is the initial design and there is a possibility to change the design according to the modification of material, equipments and array of structure.

• Journal of ILASS-Korea
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• v.24 no.1
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• pp.1-7
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• 2019

This study was carried out to analyze the spray characteristics as a function of the operating parameters of urea injector used in Urea-SCR system of passenger diesel vehicle. Spray visualization and PDPA experiment were performed to analyze the macroscopic spray development and atomization performance of urea-water-solution. For the urea injector, the deformation of the spray head does not appear to be significant because it operates at a low pressure conditions, and the liquid core and primary droplet are observed throughout the operating conditions. No increase in atomization is seen when the operating pressure is increased, and the spray develops linearly due to poor atomization characteristics. The macroscopic spray behavior of the low-pressure urea injector is predictable through the modification of the Hiroyasu equation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.5
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• pp.919-929
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• 2013

Recently, a variety of IT technologies are applied to the vehicle. However, some vehicle-IT technologies without security considerations may cause security problems. Specially, some researches about a smart key system applied to automobiles for authentication show that the system is insecure from replay attacks and modification attacks using a wireless signal of the smart key. Thus, in this paper, we propose an authentication method for the driver by using driving patterns. Nowadays, we can obtain driving patterns using the In-vehicle network data. In our authentication model, we make driving ppatterns of car owner using standard normal distribution and apply these patterns to driver authentication. To validate our model, we perform an k-fold cross validation test using In-vehicle network data and obtain the result(true positive rate 0.7/false positive rate is 0.35). Considering to our result, it turns out that our model is more secure than existing 'what you have' authentication models such as the smart key if the authentication result is sent to the car owner through mobile networks.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.1
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• pp.29-37
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• 2013

The purpose of this study is to suggest the potential domestic and international market conditions vehicles for people with disabilities through a review of the literature and internet resources, and to propose a road map developing South Korean vehicles for people with disabilities taking into consideration the current state of domestic and international technology and the usage of the vehicles for people with disabilities depending on the type of disability. The results of the study are as follows: First, vehicles for people with disabilities safety standards of South Korea do not meet the safety standards of developed countries and the technology of development related vehicles for people with disabilities is not as advanced as that of developed countries. Vehicles for people with disabilities installation methods, specifications, features and safety standards should be designed to be more similar to those of Japan and the United States. Second, vehicle modifications for people with disabilities will become more common as measures directed at promoting the welfare of people with disabilities, such as travel and transportation measures, employment opportunities, education, and funding for vehicle modifications, are implemented along with laws, such as The Americans with Disabilities Act, The British Disability Discrimination Act, and Japan's barrier-free transport law, that protect people with disabilities generally. Third, through a comparative analysis of domestic and international market conditions and demands of people with disabilities in vehicle modifications, important things to pay attention by purchasing a modified vehicle for people with disabilities are the employment rate for people with disabilities and monthly income. To enable this, government agencies and industry bodies should work together through the revision of the current Disability Welfare Act or the enactment of the special law for guiding principles of Disability Welfare Act. Through the future changes in vehicles for people with disabilities-related system or society of South Korean, the annual demand of the vehicles is expected to be more than 10,000.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.1
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• pp.13-21
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• 2018

AGVS (Automated Guided Vehicle System) is a core technology of logistics automation which automatically moves specific objects or goods within a certain work space. Conventional AGVS generally requires the in-door localization system and each AGV equips expensive sensors such as laser, magnetic, inertial sensors for the route recognition and automatic navigation. thus the high installation cost is inevitable and there are many restrictions on route(path) modification or expansion. To address this issue, in this paper, we propose a cost-effective and scalable AGV based on a light-weight pattern recognition technique. The proposed pattern recognition technology not only enables autonomous driving by recognizing the route(path), but also provides a technique for figuring out the loc ation of AGV itself by recognizing the simple patterns(bar-code like) installed on the route. This significantly reduces the cost of implementing AGVS as well as benefiting from route modification and expansion. In order to verify the effectiveness of the proposed technique, we first implement a pattern recognition algorithm on a light-weight MCU(Micro Control Unit), and then verify the results by implementing an MCU_controlled AGV prototype.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.2
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• pp.14-18
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• 2015

In recent years, world is faced with a transportation energy dilemma, and the transportation is almost dependent on a single fuel - petroleum. However, Hybrid Electric Vehicle (HEV) technology holds more advantages to reduce the demand for petroleum in the transportation by efficiency improvements of petroleum consumption. Therefore, there is a trend that lower gear noise levels are demanded in HEV for drivers to avoid annoyance and fatigue during operation. And meshing transmission error (T.E.) is the excitation that leads to the tonal noise known as gear whine, and radiated gear whine is also the dominant source of noise in the whole gearbox. In this paper, the analysis of gear tooth profile and lead modification is firstly presented, and then, the different transmission error of no mesh misalignment and mesh misalignment under one loaded torque for the 1st gear pair of HEV gearbox was investigated and compared. At last, the appropriate tooth modification was used to minimize and compare the transmission error of the gear pair with mesh misalignment under the loaded torque.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.1-8
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• 2019

In the rapidly aging society, the number of wheelchair users is increasing steadily. On the other hand, it is almost impossible for a disabled person using a wheelchair to use express buses. Therefore, it is necessary to develop an express bus that can secure the rights of wheelchair users. For these special types of express buses, it is required to develop a special entrance and lift system. The development of a wheelchair entrance system for the express buses requires design modification, retrofit, and reinforcement of the bus frame. This study evaluated the structural integrity of an entrance system for wheelchair users using a finite element method. Torsional stiffness and modal analysis were performed through structural analysis. Through sensitivity analysis, optimization was performed to reduce the weight of the frame. These results on the wheelchair entrance system are expected to be utilized in the vehicle modification and welfare industries.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.385-391
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• 2023

As the use of electric vehicles has increased to minimize carbon emissions, the analyzing the state and performance of lithium-ion batteries that is instrumental in electric vehicles have been important. Comprehensive analysis using not only the voltage, current and temperature of the battery pack, which can affect the condition and performance of the battery, but also the driving data and charging pattern data of the electric vehicle is required. Therefore, a thorough analysis is imperative, utilizing electric vehicle operation data, charging pattern data, as well as battery pack voltage, current, and temperature data, which collectively influence the condition and performance of the battery. Therefore, collection and preprocessing of battery data collected from electric vehicles, collection and preprocessing of data on driver driving habits in addition to simple battery data, detailed design and modification of artificial intelligence algorithm based on the analyzed influencing factors, and A battery analysis and evaluation model was designed. In this paper, we gathered operational data and battery data from real-time electric buses. These data sets were then utilized to train a Random Forest algorithm. Furthermore, a comprehensive assessment of battery status, operation, and charging patterns was conducted using the explainable Artificial Intelligence (XAI) algorithm. The study identified crucial influencing factors on battery status, including rapid acceleration, rapid deceleration, sudden stops in driving patterns, the number of drives per day in the charging and discharging pattern, daily accumulated Depth of Discharge (DOD), cell voltage differences during discharge, maximum cell temperature, and minimum cell temperature. These factors were confirmed to significantly impact the battery condition. Based on the identified influencing factors, a battery analysis and evaluation model was designed and assessed using the Random Forest algorithm. The results contribute to the understanding of battery health and lay the foundation for effective battery management in electric vehicles.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.1025-1031
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• 2007

GPS is widely used for positioning applications and attitude of a vehicle can be found also with multiple antennas. However, extremely weak signal level prevents GPS from indoor operation. DR with accelerometers and gyros and landmark based localization method used for indoor applications increase complexity and cost. In this paper, a simple but very efficient ultrasound based attitude determination system which determines both position and attitude in WSN is given. The range between transmitter and receivers are measured using the arrival time difference between ultrasound and RF signal. The 3 dimensional positions can be found using more than 3 range measurements. Furthermore, if more than 2 transmitters are used, the attitude can be determined using the baseline vectors obtained by differencing transmitter and receiver positions. The prototype system is implemented to evaluate the performance of the proposed method. In addition, an error analysis shows the relation between the attitude error and basel me length, quality of measurement and orientation of a vehicle. The static and dynamic experiments performed by micro mobile robot shows accurate position with less than 1.5cm error and attitude with less than 1 degree error can be obtained continuously with 20cm baseline. It is expected that these results can be adapted without modification to indoor applications such as home cleaning robot and autonomous wheelchair maneuvering.