Depaiwa, Nattawoot

Preferred name

Depaiwa, Nattawoot

Alternative Name

Depaiwa, N.

Main Affiliation

School of Engineering

nattawoot.de@kmitl.ac.th

Now showing 1 - 10 of 10

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DETECTION OF DRIVER DROWSINESS FROM EEG SIGNALS USING WEARABLE BRAIN SENSING HEADBAND
(2021-05-31)
Chan, Khune Satt Nyein
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Srisurangkul, C.
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Depaiwa, N.
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Pangkreung, S.
Driver drowsiness detection plays an important role in the field of road safety and advanced driver assistance system. Electroencephalogram (EEG) signals are one of the most accurate and reliable indicators of fatigue and drowsiness but in the case of detecting drowsiness, its medical graded measuring system can be intrusive to the driver. The purpose of this research is to test the feasibility and usability of the consumer graded EEG sensor to use in a driver drowsiness detection system. The experiment was carried out by using MUSE S brain sensing headband. Fast Fourier Transform (FFT) method was used to extract features from EEG signals. The extracted feature data are then used to build two classification model, the Support Vector Machine (SVM) and Artificial Neural Network (ANN). The detection of drowsiness is the binary classification task which is to classify between drowsy epochs and alert epochs. In the case of detecting only drowsy epochs, the SVM model detected 82.7% of the drowsy epochs which was better than the ANN model which can only detect 81.25% of the drowsy epochs. But in the detection of both drowsy and alert epochs, the ANN model performed better than that of SVM. The SVM model was tested with different kernel function and Fine Gaussian SVM model showed the highest accuracy of 87.8%. The ANN model performed slightly higher than the SVM model with an accuracy of 87.9%. The ability of consumer graded EEG sensor to use in drowsiness detection system was validated in this research.
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Impact of Driving Behavior on Power Consumption of Electric Bus: A Case Study on Rama IX Bridge
(2022-01-01)
Phyo, Lwin Yamon
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Depaiwa, Nattawoot
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Yamakita, Masaki
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Kerdsup, Burin
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Masomtob, Manop
Recently, the influence of the bus transportation system in Thailand has become the most critical impact on our surroundings. Government of Thailand has initiated the projects to replace internal combustion engine buses with net zero-emission. However, there are the problems of power consumption in battery electric buses, especially on climbing resistance which is a major impact on the power demand and recuperation. This paper aims to investigate the impact of driving behavior on power consumption of electric buses. Many scenarios have been created to study such behavior. Also, driving across Rama IX bridge which is the critical scenario on the performance of electric buses in Thailand has been evaluated.
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Active Vibration Absorber with Curved Beam Design
(2023-01-01)
Rodyoo, Itsawat
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Depaiwa, Nattawoot
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Pinsopon, Unnat
The project aims to design and create an active vibration absorber with a curved beam to reduce vibration. The selected frequency of the vibration generator for this research was limited to 10 to 30 revolutions per minute and is forced to move in one dimension. The vibration generator was controlled by variable resistance with an unbalanced mass that produces centrifugal forces between 14.799 and 133.189 newtons at frequencies of 10 and 30 revolutions per minute, respectively. To control the natural frequency of the active vibration absorber, the microcontroller STM32F103C8T6-Black Pill and absorption frequency was used with a set of controlling criteria that help to adjust a spring's stiffness. The spring was designed as a curve beam so that the absorber would be small and easy to use while having a wider working range and reacting quicker to a change in load. To reduce system vibration, the spring stiffness was properly adjusted by changing the curve beam's length by changing the locker arm's position using a rotating motor. The feedback control system, meanwhile, was used to adjust the motor's position through variable resistance and then calculate a feedback error to the corrected position, resulting in a natural frequency of the absorber that was similar to the system's vibration frequency. Moreover, the relationship between spring stiffness and curve beam length was also investigated to obtain the function of locker arm position and specify the angle of the motor's shaft. Experiments to test the correctness of theory and method were also conducted. Prior to the experiment, the vibration absorber's efficiency was assessed using ADAMS motion simulation software. The efficiency as a percentage drop in the main system vibration amplitude was calculated while the vibration absorber was mounted. At an operating frequency of 15 Hz, which is close to the natural frequency of the main system, the test results show that the vibration can be reduced by up to 65.49 percent. However, based on the experiment's results, the efficiency was defined as a percentage of a reduction in vibration amplitude in the primary system, both with and without an active absorber. The most efficiency as a percentage drop in the main system vibration amplitude was 34.917%, while the least efficient was 7.711%. It was concluded that the active vibration absorber design with the curved beam can reduce vibration, and while the results were not the best, they were enough to warrant the commencement of future studies.
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Development and Design Structure and Mechanism of Sugarcane Harvester with Leaf Pruning Machine
(2023-01-01)
Jukgoljun, Wisawa
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Moonumca, Pisan
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Depaiwa, Nattawoot
The purpose of this research is to design, develop, and analyze the damaged structure and mechanism of sugarcane harvesters, then find suitable materials to use for sugarcane harvesters that respond to the needs of farmers. Nowadays, sugarcane harvesters are quite expensive. Consequently, most people prefer to harvest sugarcane by burning the leaves before cutting, which causes air pollution. The authors decided to start designing and developing the whole sugarcane cutting machine. The leaves and stems can be cut with a machine that only uses power from the power take-off shaft. The authors also analyzed the properties that affected the experiment's results. It can be concluded that in terms of the material, the properties should be considered as follows: The tensile value should be greater than 3700 psi and the shear strength should be at least 10000 psi to prevent material damage from turning and pruning leaves. Hardness, meanwhile, should be lower than Rockwell M110, so the material will not cause cane damage. The Flexural Modulus of Elasticity value is about 450,000 psi. The harvesters should be connected to a tractor that has 67 horsepower or more. The whole structure works as a whole system, with no parts broken during the 48-hour trial. The machine was optimally operated using 540 rpm. of power from the power shaft. The speed of the base-cutting, using the finish-made cutter, was 337.5 rpm. The nylon lawn trimmer is the best leaf pruning tool. It is because its softness did not cause the sugarcane any damage while having no tangle in its use, which led to an improvement of the machines. Results showed that harvesters can harvest up to 300 sugarcanes per hour using this machine.
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Influence of ethanol biodiesel blends on a diesel engine's efficiency and exhaust emission characteristics
(2022-01-01)
Kanokkhanarat, Phobkrit
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Karin, Preechar
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Depaiwa, Nattawoot
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Wongpattharaworakul, Veerayut
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Srisurangkul, Chadchai
The harm caused by polluted air occurs from dust, smoke, or soot. One of the main causes of pollutions is exhaust emission that comes from diesel engines of cars, trucks, buses, heavy machines, or generators for industrial because their thermal efficiency, torque, and performance are higher than the other engines. To reduce the emission from diesel engines, the fuel substitute for biodiesel which is made from based palm oil is one of the alternatives to use. So, the purpose of this paper is an experimental investigation of the engine performance, combustion characteristics, and smoke intensity of commercial biodiesel fuels (B10 and B20), pure biodiesel fuel (B100), and pure biodiesel blended with ethanol fuels (B100E5 and B100E10), which were performed at various loads (56, 84, 112, and 140Nm) and conducted at constant engine speeds (1000, 1500, and 2000 rpm). The experimental results show that pure biodiesel fuel (B100) and pure biodiesel blended with ethanol fuels (B100E5 and B100E10) have engine performance and combustion characteristics similar to commercial biodiesel fuels (B10 and B20). However, pure biodiesel fuels (B100) and pure biodiesel blended with ethanol fuels (B100E5 and B100E10) can reduce the emissions as the smoke intensity from commercial biodiesel (B10 and B20) is more than 50%.
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IMPROVEMENT OF ESTIMATION METHOD FOR BATTERY CELL HEAT GENERATION
(2021-05-31)
Kulranut, J.
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Depaiwa, N.
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Yenwichai, T.
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Intano, W.
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Masomtob, M.
This work represents a new experimental method to precisely estimate the heat generation of the battery cell by reducing heat losses to the ambient. The temperature ambient in the chamber is controlled to be close to the battery cell temperature as much as possible in order to reduce the heat loss from the battery to the ambient. The battery is covered by an insulator, and the heat loss due to the heat conduction at the electric connectors is also considered. Therefore, the heat generation term is absorbed by the heat capacity term; in other words, the heat generation of the battery cell can be calculated via the rising temperature of the heat capacity term and the heat loss of the connectors. Consequently, this new method can obtain the precision of the estimated heat generation that can be used to design an appropriate battery thermal management system for the battery pack.
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Investigation of the Impact Bioethanol Blends into Biodiesel on Combustion Characteristics, Engine Performance, and Emissions of Diesel Engine
(2022-01-01)
Kanokkhanarat, Phobkrit
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Depaiwa, Nattawoot
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Karin, Preechar
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Wongpattharaworakul, Veerayut
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Srisurangkul, Chadchai
Emissions from a diesel engine are dangerous to the environment and human health. Substitutable fuels from a renewable source are one of the alternatives to reduce emissions. Neat biodiesel from based palm oil (B100) can reduce emissions from higher oxygen content to be more complete combustion. The disadvantage of neat biodiesel is lower thermal efficiency from an advancement ignition. To improve this problem, adding bioethanol produced from agriculture products into neat biodiesel by weight ratio as B100E5 (95% B100 with 5% bioethanol) and B100E10 (90% B100 with 10% bioethanol). Hence, the focus of this research is to examine the combustion and emission characteristics, including engine performance, of bioethanol blends into neat biodiesel fuels (B100E5 and B100E10) compared with neat biodiesel (B100). All samples were tested at an engine load of 140 NM with constant engine speeds of 1000, 1500, and 2000 RPM on a diesel engine. The results of bioethanol blends into biodiesel fuels indicate that the pressure in the combustion cylinder and rate of heat release increase with increasing percentages of bioethanol. B100E10 shows the highest brake thermal efficiency. The smoke intensity of bioethanol blends into biodiesel fuels is reduced by more than 50% when compared to neat biodiesel fuel, and higher NOx emission from higher oxygen content in the fuels.
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A Directional Control Auxiliary Thrust System to Increase the Forward Speed of a Quadcopter UAV
(2024-01-01)
Srijun, Chanapan
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Depaiwa, Nattawoot
This research introduces a method to increase the horizontal speed of a quadcopter UAV using an auxiliary thrust system that can be adjusted in direction. The researcher used thrust vectoring control to align the thrust direction with the unmanned aircraft's longitudinal axis. A method for controlling a device mechanism using a proportional-integral-derivative (PID) control system. Based on the test results, it has been concluded that the Ziegler–Nichols Method in P controller, the Ziegler–Nichols Method in PD controller, and the Trial-and-Error method in PID controller are the most effective methods for maintaining system stability and achieving the setpoint. It took 0.693, 1.441, and 0.563 seconds respectively to reach the desired value. The researcher used computational fluid dynamics and equations of motion to simulate a UAV's speed. The simulation results of using 25% additional thrust while moving at a 2-degree angle showed that the unmanned aerial vehicle's speed increased by 35.3% compared to the unmanned aerial vehicle without the auxiliary thrust system. When the pitch angle was increased to 5 degrees, the speed of the UAV increased by 15.9%. At higher pitch angles of 10 degrees, the UAV's speed increased by 6.86%. Finally, at pitch angles of 15 degrees, the speed of the UAV increased by 4.97%.
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Experimental investigation of the influence of ethanol and biodiesel on common rail direct injection diesel Engine's combustion and emission characteristics
(2022-11-01)
Wai, Phyo
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Kanokkhanarat, Phobkrit
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Oh, Ban Seok
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Wongpattharaworakul, Veerayut
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Depaiwa, Nattawoot
This study aims to characterize the effect of oxygenated biofuels in diesel engine combustion, thermal efficiency, and emission by blending different percentages of ethanol and biodiesel with fossil fuel derived diesel. In this research, 5% and 10% by weight of bioethanol were added to commercial B10 (10% biodiesel and 90% diesel), B20 (20% biodiesel and 80% diesel) and B100 (100% biodiesel) and experimented on using a 3 L four-cylinder common rail diesel engine. The experiment was performed under three engine speeds of 1000 rpm, 1500 rpm, and 2000 rpm with three constant engine torques of 56 Nm, 84 Nm, and 140 Nm. The results show that ethanol-biodiesel-diesel ternary blended fuels are higher in premixed combustion pressure and net heat release rate (NHRR) peaks. The cumulative heat release of ethanol blended fuels is also higher for ethanol blended fuels. The fuel consumption increased with the ethanol and biodiesel percentage in the blended fuels due to the lower heating value while the brake thermal efficiency did not decrease. It was clearly observed that the particle emission could be reduced by more than 50% when ethanol and biodiesel percentage increased.
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Effects of Rotor Eccentricity on Interior Permanent Magnet Motor Performance in Electric Vehicles
(2025-01-01)
Ho, Truc Hoang
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Chayopitak, Nattapon
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Pupadubsin, Ruchao
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Depaiwa, Nattawoot
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Saito, Takushi
Interior Permanent Magnet (IPM) motors are a popular choice in electric vehicle (EV) powertrains because of their high efficiency, compact size, and controllability. Rotor eccentricity remains a significant challenge because it introduces unbalanced magnetic forces, which increase vibrations, noise, and the risk of premature motor failure. This study investigated the effects of static, dynamic, and mixed eccentricity on the performance of IPM motors and explored how numerical analysis can aid in fault detection during the design and diagnostic phases. This study aims to explore eccentricity fault conditions and their impacts on the motor torque, cogging torque, and magnetic flux density using Finite Element Analysis (FEA) with frequency spectrum analysis. The results show that three types of eccentricity being considered: static, dynamic, and mixed type, produce distinct harmonic signatures that significantly affect the motor's performance characteristics. Specific harmonic ranges are particularly sensitive to different fault types that provide key indicators for early fault detection.

Depaiwa, Nattawoot

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