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Fin Coil Dent Detection Using Deep Learning
(2025-01-01)
Tantrapiwat, Akapot
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Pinsopon, Unnat
This work introduced the object detection using deep learning in order to detect and locate dents on fin coils. It was aimed at using the AI as a tool to detect fin coil dents and restore them in the fin coil manufacturing and assembly processes. Not only were the images of dents used to train object detection models, two different types of distinctive marks were added for the purpose of positioning calibration in the system. Three scalable models of the state-of-art EfficientDat D0, D1 and D2 were used and compared for their accuracies and performances. All models were trained successfully with the custom dataset. It took only 30 epochs to achieve a functionable performance. The dent detection accuracies which were considered from the True Positive, obtained from the D0, D1, and D2 models were 55%, 66% and 75 % respectively. The three models can identify additional marks with 100% accuracy. In all models, there was no False Negative detection in all object classes showing good potential of using the models in the real applications.
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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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Friction Compensated Force Control of Electro-Hydraulic System Using Fuzzy Controller
(2022-10-31)
Chanbua, Weerapong
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Pinsopon, Unnat
Steady state and dynamic LuGre friction models of an electro-hydraulic system were constructed. Indirect electro-hydraulic cylinder force control under friction compensated PID and fuzzy controllers were tested and compared. Feedback force signal was indirectly measured and calculated from pressures to emulate the applications that direct force measurement is impossible. Estimated friction was compensated to desired force command of the PID controller. The proposed fuzzy controller contained two modules. The first, as a friction compensator, calculated modified error according to estimated friction and feedback force error. The second module calculated control action based on PD control scheme. Friction compensated PID and fuzzy controllers could reduce tracking errors at the maximum force commands by 80% and 90%, respectively, compared to the PID controller without compensation. The steady state friction compensation yielded better tracking performances compared to the dynamic friction. Tracking performance of the fuzzy controller was always better than the PID controller
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Production Potential Assessment of Biogas from Napier Grass Using Geographic Information
(2022-01-01)
Khotmanee, Saran
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Pinsopon, Unnat
Thailand 2015 Alternative Energy Development Plan declared that 1,280 MW of electricity, 1,283 ktoe equivalent of heat production, and 4,800 ton/day transport biofuel would be sourced from biogas by the year 2036. To understand the current situation, Thailand biogas production potential from Napier grass by region was investigated. Napier grass was assumed to be cultivated only on the unused land. Geographic information of land use and soil type was overlayed on the country map to identify suitable Napier grass cultivation areas. Annual accumulated precipitation of each province was also taken into account to calculate the Napier grass crop yield. The study shows that Napier grass could be cultivated in all parts of Thailand. At present the Napier grass crop yield and biogas production potentials are found to be 189,237,760 ton/year and 11,354 million m3/year, respectively.
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A Study on Biogas Production Potential in Thailand 2019
(2021-04-01)
Khotmanee, Saran
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Pinsopon, Unnat
Thailand 2015 Alternative Energy Development Plan (AEDP2015) stated that renewable energy should take part in the gross energy consumption for 30% by the year 2036. The plan also targeted compressed biogas to replace refined petroleum for a daily use 4,800 tons, as well as the biogas produced from waste to be the source for a 600 MW electricity power generation. To understand how close the biogas production status is up to the plan, the biogas production potential in Thailand 2019 was investigated, and is presented in this paper. The biogas production potential was considered from 3 sectors: industrial plants, livestock, and agricultural plants. The industrial plants with high organic content of waste were considered in the study. They are ethanol, starch, palm oil, rubber, food and alcoholic beverage plants. Livestock investigated in this study are cattle, buffaloes, pigs and chickens. Top 6 most cultivated agricultural plants were considered: rice, corn, sugarcane, cassava, palm and pineapple. Only business units with significant production potential yields were included in the potential study. The biogas productivity status in the year 2019 was also surveyed. The biogas production potential in Thailand 2019 was estimated to be 22,827 million m3, higher than the planned demand of 8,124 million m3 in the year 2036 due to the AEDP2015 plan. However, the productivity status was found to be 816 million m3, only 10% of the planned value in the year 2036. Continual supports from the government are needed in order that the biogas productivity could meet the targeted demand in the year 2036.
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Friction Compensated Fuzzy Force Tracking Control of Electro-Hydraulic System
(2020-04-01)
Chanbua, Weerapong
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Pinsopon, Unnat
Friction is one of the main cause that affects the tracking accuracy of the control system. This study presents the steady state friction estimation in a hydraulic cylinder. Cylinder force tracking of PID and fuzzy PD control systems under friction compensated reference were tested and compared. Fuzzy control system, which has a more design flexibility compared with PID, yielded a better tracking performance, with 10% and 14% better in average tracking error at maximum compression and RMS error, respectively.
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Experimental study on sound characteristics of Ja-Khay strings
(2019-07-01)
Wangwiwattana, Teerawat
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Saguanrum, Sayam
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Kittimathaveenan, Kajornsak
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Pinsopon, Unnat
This research explored sound characteristics of eight different strings on Ja-Khay, a Thai classical floor zither. The strings were investigated the suitability of being the first brightest string. Physical properties of each string such as linear density, elastic modulus and tension required to make a 262 Hz C<inf>4</inf>-note sound were tested and measured. The sound produced by each string was recorded in the recording studio of Music Engineering and Multimedia Department, King Mongkut's Institute of Technology Ladkrabang. Temporal and spectral responses of the sound produced by eight test strings were analyzed. The relationship between physical properties and sound characteristics such as maximum loudness, sustain, richness and brightness of the sound was investigated. The good sound characteristics of three most well-liked strings according to the survey: Construction string number 120, tennis string and Saw-U silk string, were confirmed by the analytical data.
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Velocity control of electro-hydraulic pump control system using gear pump
(2018-12-01)
Jangnoi, Tossapol
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Pinsopon, Unnat
Two types of velocity control electro-hydraulic systems, valve and pump flow control systems, were extensively investigated in this study. Valve flow control system tested in the study was one of the conventional types with the use of proportional valve and conventional gear pump. The proposed pump flow control system was of the simplest one. An inverter type variable speed drive was used to drive the same gear pump in order to adjust the pump speed and hence the discharge flow rate according to the desired cylinder velocity. Mathematical model of the pump flow control system is presented in the article, and its numerical simulation results were obtained by solving the state space equations. Open loop and proportional-integral (PI) closed loop performances of both valve and proposed pump flow control systems were tested and compared. Velocity tracking performance of valve flow control system either under open loop or PI closed loop control was always better than the proposed pump flow control system. However, the power consumption of the proposed system was much better than the valve flow control system. Response speed in terms of bandwidth frequency of the proposed system under open loop control was less than the valve flow control system by half due to the large inertia of motor-pump rotor. Under PI closed loop control, bandwidth frequency of the proposed system was improved to be 15% less than the valve flow control system.
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PID electro-hydraulic cylinder force tracking system with friction compensation
(2018-08-14)
Chanbua, Weerapong
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Pinsopon, Unnat
Friction can be found in all mechanical systems, and is the cause of control tracking error. In this article, LuGre friction model for symmetric hydraulic cylinder was studied and obtained experimentally. The estimated friction force was applied for reference force compensation. Force tracking performances of PID force control systems with and without friction compensation were tested and compared. Control system with friction compensation outperformed one without in all cases of tracking tests. The best result was found in the square force tracking tests, with an average error at maximum compression force of 86.105 N in the case of with friction compensation compared with error of 511.996 N in the case without. However, the estimated friction achieved in the study was noisy. This is due to the use of noisy numerically differentiated velocity signal in the friction estimation procedure.
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Influence of RBD palm olein on hydraulic pump performance
(2014-01-01)
Chanbua, Weerapong
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Pinsopon, Unnat
At the present time, researchers try to find alternative fluids for being used as lubricants or hydraulic fluids that are biodegradable and environmental friendly. In this study, Refined- Bleached-Deodorized (RBD) palm olein was investigated whether it is such a potential candidate. RBD palm olein could be easily acquired since it is of the type used as cooking oil. The physical properties of both conventional hydraulic oil and RBD palm olein were tested and compared by an accredited laboratory. The performance of the hydraulic systems when using both fluids as working mediums were also tested and compared. The experimental results show that temperature significantly affected the performance of the hydraulic system when using conventional hydraulic oil, whereas the performance of the hydraulic system when using RBD palm olein barely changed with temperatures. At the temperatures below 60°C, the RBD palm olein yielded less flow rate and less energy efficiency. However, for the temperatures above 60°C, the RBD palm olein yielded slightly more flow rate and slightly more energy efficiency. It can be confirmed from this study that RBD palm olein can be used as an alternative hydraulic fluid. © (2014) Trans Tech Publications, Switzerland.

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