• Journal of Electrical Engineering and Technology
• /
• v.5 no.2
• /
• pp.307-318
• /
• 2010

In this work, an accurate analysis of low frequency current ripple in residential fuel cell power generation systems is performed based on the proposed residential load model and its unique operation algorithm. Rather than using a constant dc voltage source, a proton exchange membrane fuel cell (PEMFC) model is implemented in this research so that a system-level analysis considering the fuel cell stack, power conditioning system (PCS), and the actual load is possible. Using the attained results, a comparative study regarding the discrepancies of low frequency current ripple between a simple resistor load and a realistic residential load is performed. The data indicate that the low frequency current ripple of the proposed residential load model is increased by more than a factor of two when compared to the low frequency current ripple of a simple resistor load under identical conditions. Theoretical analysis, simulation data, and experimental results are provided, along with a model of the load usage pattern of low frequency current ripples.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2054-2057
• /
• 2005

In this paper, the application of finite element method to design the shape of load cell as an illustrative case study is described. The relationship between the various shapes of load cell and their stress characteristic were analyzed by COSMOS simulation program. The results obtained from the proposed analysis can be applied to determine the appropriate position of strain gauges for good quality load cell. The experimental results show the good efficiency of the proposed technique.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.2
• /
• pp.152-159
• /
• 2001

This paper presents a development of the recoil rod pull force measurement system suing the load cell with a sleeve normally available in the recoil system test. The commercial load cell cannot be used in the test of recoil system floating the breach contact point freely in the air. The load cell is designed and manufactured to meet the recoil system test condition. Theoretical analysis and experimental results show that the accuracy of the developed measurement system is within $\pm$0.5%. We notice that the measurement technique proposed in this paper is accurate and useful in the recoil rod pull force measurement of the recoil system.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.3 s.96
• /
• pp.222-232
• /
• 1999

This paper describes the development of a precision 3-component load cell with plate beams which may be used for measuring forces Fx, Fy and moment Mz simultaneously in industry. We have derived equations to predict the bending strains on the surface of the beams under forces or moment. We have also determined the attachment location of strain gages of each sensor and fabricated 3-component load cell. To evaluate the rated strain and interference error of each sensor, we have carried out characteristic test of precision 3-component load cell. It reveals that the rated strain calculated from the derived equations are good agreement with the results from Finite Element Method analysis.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.476-481
• /
• 2009

Bi-directional load test is one of O-cell tests. The O-cell test is a system which may be used for performing static load tests on cast in situ reinforced concrete bored piles. The technique was devised and developed by Osterberg of Northwestern University(USA) and has been in use around the world. The principle of the method is that an O-cell is installed in a cast in situ bored pile base. Once the pile concrete reaches its design strength the cell is connected to an hydraulic pump and pressured. Pressurization causes the cell to expand, developing an upward force on the section of pile above the cell loads, pile movements and strains within the pile then enable the capacity of the pile and its load settlement curves to be ascertained. The O-cell pile load test with variable end plate is operated on second steps - the first step is to confirming end bearing capacity with variable end plate and the second step is similar to the conventional O-cell test. In the study, To calculate ultimate capacity of bi-directional load test using model with the pile with variable end plate O-cell.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.229-234
• /
• 2005

Thin-walled multicell box girders subjected to an eccentric load can he produced the three global behaviors of flexure, torsion, and distortion. Specially in railway bridges subjected to much eccentric load, it is quite important to evaluate influences of torsion and distortion. But it is very difficult to evaluate each influences of major behaviors numerically. If we can decompose an eccentric load P into flexural, torsional, and distortional forces. we can execute quantitative analysis each influences of major behaviors. Decomposition of Applied Load for Thin-walled Rectangular multi-cell box girders is reserched by Park, Nam- Hoi(Development of a multicell Box Beam Element Including Distortional Degrees of Freedom, 2003). But researches about trapezoidal multi-cell section is insufficient. So, this paper deals with multi-cell trapezoidal box girders. An expanded method, which is based on the force decomposition method for a single cell box girder given by Nakai and Yoo, is developed herein to decompose eccentric load Pinto flexural, torsional, and distortional forces. Derive formulas by decomposition of eccentric load is verified by 3D shell-modelling numerical analysis.

• Proceedings of the KIEE Conference
• /
• 2005.07d
• /
• pp.2738-2740
• /
• 2005

From composition transmitter is detached in indicator to individual load direction of 4 channels and adding up display by load cell indicator indication method of Bluetooth way is identifying marks.

• Journal of Sensor Science and Technology
• /
• v.31 no.6
• /
• pp.411-417
• /
• 2022

In this paper, we propose a sensor with a C-shaped load cell to detect force change when a person sitting on the chair in an electrical transport-convenience vehicle is pushing ground by both heels. The load cell built in the vehicle is mechanically deformed by the vertical force owing to the human weight and the horizontal force by ground-pushing feet. The deformation rate of the load cell and its distribution are simulated using finite element analysis. In the simulation, the applied loads are preset in the range of 10 kg - 100 kg with a step size of 10 kg, and the ground-pushing force by feet is increased to 40 N with a step size of 5 N with respect to each applied load level. The resistance change of the load cell was observed to be linear in simulation as well as in measurement. the maximum difference between simulation and measurement was 0.89 % when the strain gauge constant was 2.243. The constant has a large influence on the difference. The proposed sensor was fabricated by connecting an instrument amplifier and a microcontroller to a load cell and used to detect the force by ground-pushing feet. To detect foot driving, the reference signal was set to 130% of the load, and the duration of the sensor output signal exceeding the reference signal was set to 0.6 s. In a test of a vehicle built with the proposed sensor, the footpushing force by the worker could be successfully detected even when the worker was working.

• Transactions of the Korean hydrogen and new energy society
• /
• v.35 no.2
• /
• pp.121-128
• /
• 2024

In this study, a dynamic simulation model of a heavy-duty truck, equipped with a fuel cell power-train, has been developed and the dynamic behavior of the fuel cell stack has bee investigated using. Output change simulations were performed according to several drive cycle load change of a fuel cell truck. Mathworks' Simulink and Simscape program were used to develop the model. The model is comprised of fuel cell power train, power converter system and truck vehicle part. The vehicle runs at targeted speed of the truck, which is set as the load of the system. The dynamic behavior of the fuel cell stack according to the weight difference were analyzed, and based on this, the dynamic characteristics of the fuel cell output power and battery state with simple load was analyzed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.11 no.1
• /
• pp.114-122
• /
• 1997

This paper describes the design and development of a smart digital load cell used forweighing installations. Sice the load cell sensor to be used is very sensitive for weight cariation, the load cell must have the temperature stability, low-drift and the high-resolution of the A/D conversion for accuracy. A new analog circuit which is controlled by one chip micro-processer has been developed to reduce the offset voltage and the drift characteristics of operational amplifiers, and has been adapted into the digital load cell. Also, a software algorithm has been developed to obtain the stable and accurate A/D conversion. This software includes a RS-485 communication program to control the digital load cell, which gives a capability of backing-up the calibration data and transferring control data. The simulation and evaluation of the designed digital load cell has been shown as having the good performance. which will give useful application to the weighing installations as a remote weighing sensor.