• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.1
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• pp.78-84
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• 2019

Design of an electric power system on the solar-electric vehicle is very important because sunlight intensity is changed by weather conditions and road environments. Power output of solar module on the vehicle being changed by unsteady sunlight intensity. In this paper, design method of an electric power system are proposed to generate steady electric power output. The test results shows the electric power system are effective because the solar-electric vehicle have steady driving speed under unsteady sunlight conditions.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.57.3-57.3
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• 2019

Space applications of the motion have been served with DC motors for decades. But their functionality with a gearbox and lubricants and their weights are always an issue for its application. A piezo-motor has an advantage on the direct driving with higher accuracy, smaller size, and no-EMI. We use the piezo-motor to rotate a filter wheel directly in a balloon-borne coronagraph launched on September 2019. The piezo-motor works well in a temperature range from -10 to 40 Celsius with high reliability and high positioning / tilt accuracy (~0.1degree) with a photo-encoder. We verify its functionality for 7 days. In this talk, we report the design, test processes of the filter wheel including its balloon flight result.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.403-408
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• 2023

In this paper, we introduce the results of the development of a care robot for the safe lifting and transportation of bedridden patients with difficulty moving by themselves, especially, in medical facilities. The purpose of the developed patient transfer robot is to improve the convenience of care givers and enhance the safety and comfort of care recipients by facilitating patient lifting and patient transfer tasks by applying robot technology. In order to implement the lifting function, a hoist was designed and developed, and a sway control and rollover warning system were included in the hoist module as product differentiators. In addition, in terms of implementing the transfer function, an omnidirectional movement mechanism to improve operability in confined spaces and an active safety system to prevent collisions were developed. The function of the developed patient transfer robot was verified through performance evaluation by an authorized testing agency.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.174-192
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• 2021

The LIDAR sensor, which provides higher cognitive performance than cameras and radar, is difficult to apply to ADAS or autonomous driving because of its high price. On the other hand, as the price is decreasing rapidly, expectations are rising to improve existing autonomous driving functions by taking advantage of the LIDAR sensor. In level 3 autonomous vehicles, when a dangerous situation in the cognitive module occurs due to a sensor defect or sensor limit, the driver must take control of the vehicle for manual driving. If the driver does not respond to the request, the system must automatically kick in and implement a minimum risk maneuver to maintain the risk within a tolerable level. In this study, based on this background, a LIDAR-based LKS MRM algorithm was developed for the case when the normal operation of LKS was not possible due to troubles in the cognitive system. From point cloud data collected by LIDAR, the algorithm generates the trajectory of the vehicle in front through object clustering and converts it to the target waypoints of its own. Hence, if the camera-based LKS is not operating normally, LIDAR-based path tracking control is performed as MRM. The HAZOP method was used to identify the risk sources in the LKS cognitive systems. B, and based on this, test scenarios were derived and used in the validation process by simulation. The simulation results indicated that the LIDAR-based LKS MRM algorithm of this study prevents lane departure in dangerous situations caused by various problems or difficulties in the LKS cognitive systems and could prevent possible traffic accidents.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.2
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• pp.15-29
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• 2021

The signal intersection is the most challenging space for autonomous vehicles. To promote the safe driving of autonomous vehicles on urban roads with traffic signals, autonomous vehicles need to receive traffic signal information from infrastructure through V2I communication. Thus, a protocol for providing traffic signal information was added to the standard traffic signal controller specification of the National Police Agency. On the other hand, there are technical limitations when applying this to digital traffic signal controllers because the protocols are defined mainly for analog traffic signal controllers. Therefore, this study proposes developing a signal information linkage module to provide traffic signal information from a digital traffic signal controller to an autonomous vehicle and an algorithm improvement method that can provide accurate traffic signal information at the time of traffic signal transition.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.420-429
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• 2008

This paper describes design procedure and control strategy of HDC(High side DC/DC Converter) and MCU(Motor Control Unit) for diesel hybrid electric vehicle. In designing HDC and MCU for HEV high power density and reliability is strongly needed to meet the demand of automotive industry. In order to achieve the high performance of a controller, MPC5554 based control board is developed. An optimized film capacitor and inductor are also developed for high efficiency driving. Skim 63 IGBT module of SEMIKRON for automotive is used for power switching device. The most efficient cooling model for optimal size and reliability were verified by simulation. These procedures are verified by bench or driving test and the results are present in this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1005-1018
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• 2017

This paper proposes an App Visualization (AppV) based on IoT Self-diagnosis Micro Control Unit (ISMCU) for accident prevention. It collects a current status of a vehicle through a sensor, visualizes it on a smart phone and prevents vehicles from accident. The AppV consists of 5 components. First, a Sensor Layer (SL) judges noxious gas from a current vehicle and a driver's driving habit by collecting data from various sensors such as an Accelerator Position Sensor, an O2 sensor, an Oil Pressure Sensor, etc. and computing the concentration of the CO collected by a semiconductor gas sensor. Second, a Wireless Sensor Communication Layer (WSCL) supports Zigbee, Wi-Fi, and Bluetooth protocol so that it may transfer the sensor data collected in the SL to ISMCU and the data in the ISMCU to a Mobile. Third, an ISMCU integrates the transferred sensor information and transfers the integrated result to a Mobile. Fourth, a Mobile App Block Programming Tool (MABPT) is an independent App generation tool that changes to visual data just the vehicle information which drivers want from a smart phone. Fifth, an Embedded Module (EM) records the data collected through a Smart Phone real time in a Cloud Server. Therefore, because the AppV checks a vehicle' fault and bad driving habits that are not known from sensors and performs self-diagnosis through a mobile, it can reduce time and cost spending on accidents caused by a vehicle's fault and noxious gas emitted to the outside.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.2
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• pp.133-139
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• 2016

An electric wheelchair is a assistive device to maneuver on the ground. Tip-over of an electric wheelchair is increasing every year. Dynamic stability metric test item in KS P 7176 has not ensured safety of electric wheelchair on the slope. This study presents design the foldable electric wheelchair that can load in the car and analysis of tip-over measurement which is easily computed for electric wheelchair. Wheelchair frame is designed with a four-bar link mechanism for a foldable structure, and seat module, battery and power driving module can be separated. This analysis is performed during a maneuver on the ground by force-moment stability metric. Several elements, center of gravity position, rotational radius and acceleration, were evaluated how to affect stability metric. This stability metric can reduce tip-over of wheelchair and provide a clue to make of dynamic stability test item.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.3
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• pp.289-295
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• 2012

In recent years, an increased amount of research has been carried out on mobile robots to improve the performance of service robots. Mobile robots maximize the mobility of service robots, thus allowing them to work in different areas. However, conventional service robots have their center of mass placed high above the ground, which may cause them to fall when moving at high speed. Furthermore, hub-type actuators, which are often used for mobile robots, are large and expensive. In this study, we propose a mobile robot with a hub-type actuator unit and a variable footprint mechanism. The proposed variable footprint mechanism greatly improves the stability and mobility of the robot, allowing it to move freely in a narrow space and carry out various tasks. The performance of the proposed robot is verified experimentally.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4733-4739
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• 2012

While traditional two-axis tracking systems with double sensors had been using two sensors to control azimuth and elevation angle of the sun so that a solar cell module would make a normal line with the sun, this paper proposed a new two-axis system that can achieve the same performance with only one sensor in it. It is Two-axis tracking system that control azimuth and elevation to control to be reduced for solar cell module as proposed tracking system uses 1 sensors and the sun always forms normal. Two-axis tracking system of one sensor method that propose in paper that could reduce electric power consumption and sees than fixed type preventing action and the most efficient driving and needless drive could confirm that generation efficiency of about 23 [%] increases. To heighten efficiency of solar cell doing to receive more sunlights chasing the sun, done tracking device have proceeded a lot of studies in large size way. Therefore, is expected that will do big part in the sun tracking supply through utility study about persistent generation efficiency constructing monitoring system of the sun tracking of this paper.