• Title/Summary/Keyword: Loading Device

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Least Squares Method-Based System Identification for a 2-Axes Gimbal Structure Loading Device (2축 짐벌 구조 적재 장치를 위한 최소제곱법 기반 시스템 식별)

  • Sim, Yeri;Jin, Sangrok
    • The Journal of Korea Robotics Society
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    • v.17 no.3
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    • pp.288-295
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    • 2022
  • This study shows a system identification method of a balancing loading device for a stair climbing delivery robot. The balancing loading device is designed as a 2-axes gimbal structure and is interpreted as two independent pendulum structures for simplifying. The loading device's properties such as mass, moment of inertia, and position of the center of gravity are changeable for luggage. The system identification process of the loading device is required, and the controller should be optimized for the system in real-time. In this study, the system identification method is based on least squares method to estimate the unknown parameters of the loading device's dynamic equation. It estimates the unknown parameters by calculating them that minimize the error function between the real system's motion and the estimated system's motion. This study improves the accuracy of parameter estimation using a null space solution. The null space solution can produce the correct parameters by adjusting the parameter's relative sizes. The proposed system identification method is verified by the simulation to determine how close the estimated unknown parameters are to the real parameters.

Development of implant loading device for animal study about various loading protocol: a pilot study

  • Yoon, Joon-Ho;Park, Young-Bum;Cho, Yuna;Kim, Chang-Sung;Choi, Seong-Ho;Moon, Hong-Seok;Lee, Keun-Woo;Shim, June-Sung
    • The Journal of Advanced Prosthodontics
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    • v.4 no.4
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    • pp.227-234
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    • 2012
  • PURPOSE. The aims of this pilot study were to introduce implant loading devices designed for animal study and to evaluate the validity of the load transmission ability of the loading devices. MATERIALS AND METHODS. Implant loading devices were specially designed and fabricated with two implant abutments and cast metal bars, and orthodontic expansion screw. In six Beagles, all premolars were extracted and two implants were placed in each side of the mandibles. The loading device was inserted two weeks after the implant placement. According to the loading protocol, the load was applied to the implants with different time and method, simulating early, progressive, and delayed loading. The implants were clinically evaluated and the loading devices were removed and replaced to the master cast, followed by stress-strain analysis. Descriptive statistics of remained strain (${\mu}{\varepsilon}$) was evaluated after repeating three cycles of the loading device activation. Statistic analysis was performed using nonparametric, independent t-test with 5% significance level and Friedman's test was also used for verification. RESULTS. The loading devices were in good action. However, four implants in three Beagles showed loss of osseointegration. In stress-strain analysis, loading devices showed similar amount of increase in the remained strain after applying 1-unit load for three times. CONCLUSION. Specialized design of the implant loading device was introduced. The loading device applied similar amount of loads near the implant after each 1-unit loading. However, the direction of the loads was not parallel to the long axis of the implants as predicted before the study.

Development of One Layer Loading Hanger Device for Flue-cured Tobacco (수확 담배잎을 엮는 단선형 행거 엽편장치 개발)

  • 김용암;류명현;백종운
    • Journal of the Korean Society of Tobacco Science
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    • v.22 no.1
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    • pp.58-60
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    • 2000
  • In order to improve the loading efficiency in bulk dryer for the flue-cured tobacco leaves, a new hanger device was developed. It consists of two layers frame, in which large volume of the harvested leaves could be simply loaded. As the results of experiments with new hanger device, labor hours for loading could be saved by 34 % as compared with those in conventional 3 layers hanger, and loading capacity increased by 36%. The weight of hanger could be also reduced by 0.6kg compared to conventional 3.4kg, showing possibility of cost reduction for the developed hanger device with saved number of punching the rolled steel panels.

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Study on the Fatigue Test and the Accelerated Life Test for Dental Implant using Universal-Joint Test Type (유니버설조인트 시험방식을 이용한 치과용 임플란트의 피로시험 및 가속수명시험에 관한 연구)

  • Do, Gyeong Hun;Lee, Seok Jin;Kim, Jong Mi;Kim, Sung Min
    • Journal of Applied Reliability
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    • v.17 no.1
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    • pp.50-57
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    • 2017
  • Purpose : This paper is a comparative analysis results of the fatigue test for dental implants and accelerated life test by using a static type loading device commonly used in Korea and a dynamic type loading device (universal-joint) recommended by FDA. Methods : Fatigue tests of dental implant is based on ISO 14801 and classified into static load test and dynamic load test. The tests were carried out on three test specimens by four load stress steps under each loading device. For analysis on failure mode such as crack, fracture and permanent deformation of test specimens, we used X-ray three-dimensional computed tomography on test specimens before and after the fatigue tests. The design of the accelerated life test was based on the analysis results of the fatigue life data obtained from the dynamic load test and the statistical analysis software (Minitab ver.15) was used to analyze the appropriate life distribution. Results : As a result of the fatigue tests and the accelerated life tests at same acceleration condition under each test method, the fatigue life under the dynamic type loading device (universal-joint) was shorter than when static type loading device was applied. Conclusion : This paper can be used as a reference when the universal-joint type loading device for implants fatigue test is applied as ISO 14801.

A Study on the Development of Control Loading System for Helicopter Flight Training Device (헬리콥터 비행훈련장치용 조종력재현장치의 개발에 관한 연구)

  • Han, Dong-Ju;Lee, Sang-Haeng
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.10
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    • pp.1031-1038
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    • 2007
  • A study on the development of control loading system for a pilot command in the helicopter flight training device is performed. The key issue of the device is how to provide closely the real feeling of the stick forces to the trainer during the flight training. Focusing on this proviso and considering the suitable approach than the complexity of the hydraulic system, we adopt the AC servo motor system although its inherent disadvantages such as the torque ripple and the stick-slip friction effect at a low control force. However, we overcome these detrimental effects by introducing the appropriate control device and the robust structural design of the actuating system, thereby the feasibility and applicability to the system can be obtained by showing good performance, meeting the required specification.

A new approach for measurement of anisotropic tensile strength of concrete

  • Sarfarazi, Vahab;Faridi, Hamid R.;Haeri, Hadi;Schubert, Wulf
    • Advances in concrete construction
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    • v.3 no.4
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    • pp.269-282
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    • 2015
  • In this paper, a compression to tensile load converter device was developed to determine the anisotropic tensile strength of concrete. The samples were made from a mixture of water, fine sand and cement, respectively. Concrete samples with a hole at its center was prepared and subjected to tensile loading using the compression to tensile load converter device. A hydraulic load cell applied compressive loading to converter device with a constant pressure of 0.02 MPa per second. Compressive loading was converted to tensile stress on the sample because of the overall test design. The samples have three different configurations related to loading axis; 0, $45^{\circ}$, $-45^{\circ}$. A series of finite element analysis were done to analyze the effect of hole diameter on stress concentration of the hole side along its horizontal axis to provide a suitable criterion for determining the real tensile strength of concrete. Concurrent with indirect tensile test, Brazilian test and three point loading test were also performed to compare the results from the three methods. Results obtained by this device were quite encouraging and show that the tensile strengths of concrete were similar in different directions because of the homogeneity of bonding between the concrete materials. Also, the indirect tensile strength was clearly lower than the Brazilian test strength and three point loading test.

Development and Application of a Loading/Unloading Device for Effective Material Handling (효율적 인력물자 운반용 적.하화대의 개발 및 활용)

  • 황춘수;장통일;임현교
    • Journal of the Korean Society of Safety
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    • v.18 no.2
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    • pp.125-131
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    • 2003
  • In recent years, the Korean Army made use of fork-lifters or conveyors when loading and/or unloading military material in order to prevent accidents and to promote efficiency of military material handling activities. However, in troops smaller thin battalions, manual material handling activities are still committed for many reasons. In this thesis, a brand new loading/unloading device for efficient military material handling or manual workers was developed, and its validation study was conducted through objective assessment based on electromyography, subjective assessment based on Body-Map technique developed by Corlett and Bishop, and finally work performance comparison. The results of EMG analysis showed that muscular workload improved by 24% when using the device compared to manual work without the device, and complain of each body part was remarkably reduced. In addition, remarkable effectiveness enhancement was observed in the work performance. Consequently, it could be concluded that ergonomic devices like one developed in this research should be studied further in the ergonomic sense as well as in the economical sense.

Sensor Device Plug & Play for Ubiquitous Computing (유비쿼터스 컴퓨팅을 위한 센서 디바이스 Plug & Play)

  • Park, Jung-Sun;Eun, SeongBae;Yoon, Hyeon-Ju
    • IEMEK Journal of Embedded Systems and Applications
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    • v.7 no.3
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    • pp.151-156
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    • 2012
  • When mounting the sensor device in the way of Plug&Play, sensor device drivers need to be loaded and linked dynamically. Since a sensor node platform is based on small 8 bit MCU, dynamic loading and linking technique used in Windows and Linux can not be applied. In this paper, we present how to link and load dynamically sensor device drivers for sensor device Plug&Play. We implement a prototype and evaluate it to make sure that there is no performance degradation like sensor device driver connection speed and memory usage. Connection speed overhead increases to 0.2ms. Memory usage overhead increases to hundreds byte. It shows that there is no heavy influence in running the actual program.

Low-Soil Disturbance In-Situ Test Method Development and Its Application : Screw Plate Loading Test (지반의 교란을 최소화 한 원위치시험법 개발 및 적용 : 스크류재하시험)

  • Lee, Yong-Su;Hwang, Woong-Ki;Choi, Yong-Kyu;Kim, Tae-Hyung
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.977-986
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    • 2009
  • Sampling disturbance can introduce considerable errors in the laboratory estimation of geotechnical properties of soils, and the results obtained from sophisticated sampling and careful laboratory testing are not matching with field behavior. Therefore, it is advantage to adopt in-situ testing techniques for the estimation of geotechnical parameters. Therefore, Screw plate loading test, one of new field test technologies, has been investigated in this study. This test can be utilized to find out important properties of soils such as load-displacement, elastic modulus, and shear strength. The screw plate loading test modified from the plate loading test is an experiment underneath ground by inserting a spiral type of auger screw. The structure and characteristics of the screw plate loading test device was examined in detail. In addition, The new screw plate loading test device was manufactured to refer the previous studies. The reliability of developing screw plate loading test was examined through the analysis of the laboratory test.

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