• Multiscale and Multiphysics Mechanics
• /
• v.1 no.3
• /
• pp.261-270
• /
• 2016

The longitudinal velocity (forward speed) having significant importance in proper running of railway wheelset on track, depends greatly upon the adhesion ratio and creep analysis by implementation of suitable dynamic system on contamination. The wet track condition causes slip and slide of vehicle on railway tracking, whereas high speed may also increase slip and skidding to severe wear and deterioration of mechanical parts. The basic aim of this research is to design appropriate model aimed estimator that can be used to control railway vehicle forward velocity to avoid slip. For the filtration of disturbance procured during running of vehicle, the kalman filter is applied to estimate the actual signal on preferered samples of creep co-efficient for observing the applied attitude of noise. Thus error level is detected on higher and lower co-efficient of creep to analyze adhesion to avoid slip and sliding. The skidding is usually occurred due to higher forward speed owing to procured disturbance. This paper guides to minimize the noise and error based upon creep coefficient.

• Journal of Ocean Engineering and Technology
• /
• v.35 no.4
• /
• pp.266-272
• /
• 2021

Mooring systems are among the most important elements employed to control the motion of floating offshore structures on the sea. Considering the use of polymer material, a new method is proposed to address the creep characteristics rather than the method of using a tension load cell for measuring the tension of the mooring line. This study uses a synthetic mooring rope made from a polymer material, which usually consists of three parts: center, eye, and splice, and which makes a joint for two successive ropes. We integrate the optical sensor into the synthetic mooring ropes to measure the rope tension. The different structure of the mooring line in the longitudinal direction can be used to measure the loads with the entire mooring configuration in series, which can be defined as SMART (Smart Mooring and Riser Truncation) mooring. To determine the characteristics of the basic SMART mooring, a SMART mooring with a diameter of 3 mm made of three different polymer materials is observed to change the wavelength that responds as the length changes. By performing the longitudinal tension experiment using three different SMART moorings, it was confirmed that there were linear wavelength changes in the response characteristics of the 3-mm-diameter SMART moorings. A 54-mm-diameter SMART mooring is produced to measure the response of longitudinal tension on the center, eye, and splice of the mooring, and a longitudinal tension of 100 t in step-by-step applied for the Maintained Test and Fatigue Cycle Test is conducted. By performing a longitudinal tension experiment, wavelength changes were detected in the center, eye, and splice position of the SMART moorings. The results obtained from each part of the installed sensors indicated a different strain measurement depending on the position of the SMART moorings. The variation of the strain measurement with the position was more than twice the result of the difference measurement, while the applied external load increased step-by-step. It appears that there is a correlation with an externally generated longitudinal tensional force depending on the cross-sectional area of each part of the SMART mooring.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.361-364
• /
• 1997

The re-enty guidance design involves trajectory optimization, generation of a reference drag acceleration profile with the satisfaction of trajectory constraints. This reference drag acceleration profile can be considered as the reference trajectory. This paper proposes the atmospheric re-entry system which is composed of longitudinal, later and range control. This paper shows the a performance of a re-entry guidance and control system using feedback linearization control and predictive control.

• Journal of Korean Foot and Ankle Society
• /
• v.11 no.1
• /
• pp.8-12
• /
• 2007

Purpose: The purpose of this study was to investigate the differences in simple radiographic parameters and results of 3-D scan among normal and patient groups. Materials and Methods: Seventy subjects in each group were studied. Control group consisted of subjects without plantar foot pain (normal group), and two patient groups were one with plantar forefoot pain (metatarsalgia group), the other with plantar heel pain (heel pain group). Simple radiographic parameters were obtained and 3-D scan was done with foot scanner (Nexscan, K&I, Korea) and The height and volumn of the space under the medial longitudinal arch was analyzed (Enfoot, K&I, Korea). These parameters were compared and correlation between radiological parameters and results of the 3-D scan were studied. Results: The results of all parameters istributed normally. There was no signigicant differences among the groups in radiological parameters (talo-first metatarsal angle, calcaneal pitch angle and height of the talar head in standing lateral radiograph) and arch height and arch volumn on 3-D scan. There were statistically significant correlations between radiological and 3-D scan results. Conclusion: This study revealed that there is no significant differences in medial longitudinal arch height and volumn among normal and different patient groups and there are variety of arch height in patients with similar symptoms.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.177-180
• /
• 2009

A Possibility of combustion instability on longitudinal mode has a high level at large scale of L/D. Solid propellant has a metal particle and a grain of control to pressure oscillation. Solid rocket motor in slotted-tube grain controls pressure oscillation of longitudinal mode. If slot length is shot, pressure oscillation of longitudinal mode is amplified by cylinder part after middle phase of total burn time. A study has analyzed pressure oscillation of longitudinal mode at spectrum and acoustic modal analysis at pressure of result on static firing test.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.1 no.1 s.1
• /
• pp.81-90
• /
• 2001

This paper presents the results of the parametric study on the longitudinal behavior of 2-span continuous railway bridge. To perform the main objective of this paper, the effects of pier shaft stiffness, pier height, the size of pier foundation, and the bearing stiffness on the longitudinal behavior of the bridges are studied. Within the limits of this study, the research result has revealed that the variation of the fixed pier is more effective than that of the moved pier. In addition, the control of the hearing stiffness is much less expensive than that of any other parameters.

• Journal of Korean Society of Steel Construction
• /
• v.18 no.5
• /
• pp.633-642
• /
• 2006

Serviceability design is required to control the cracking at the joint of precast decks with longitudinal prestress in continuous composite bridges. Details of twin-girder bridges are especially complex not only due to their main reinforcements and transverse prestresses for the design of long-span concrete slabs, but also due to the shear pockets for obtaining the composite action. This paper suggests the design guidelines for the magnitude of the effective prestress and for the selection of filling materials and their requirements that would allow for the use of precast decks for twin-girder continuous composite bridges. The necessary initial prestress was also evaluated through long-term behavior analysis. From the analysis, existing design examples were revised and their effectiveness was estimated. When a filling material with a bonding strength higher than the requirement is used in the region of a high negative moment, a uniform configuration of the longitudinal prestressing steels along thewhole span length of continuous composite bridges can be achieved, which would result in the simplification of the details and the reduction of the construction costs.

• The Journal of Engineering Geology
• /
• v.26 no.2
• /
• pp.187-196
• /
• 2016

We conducted three-dimensional finite element analysis to predict the presence of upcoming fault zones during tunneling. The analysis considered longitudinal displacements measured at tunnel face, and used 28 numerical models with various fault attitudes. The x-MR (moving range) control chart was used to analyze quantitatively the effects of faults distributed ahead of the tunnel face, given the occurrence of a longitudinal displacement. The numerical models with fault were classified as fault gouge, fault breccia, and fault damage zones. The width of fault cores was set to 1 m (fault gouge 0.5 m and fault breccia 0.5 m) and the width of fault damage zones was set to 2 m. The results, suggest that fault centers could be predicted at 2~26 m ahead of the tunnel face and that faults could be predicted earliest in the 45° dip model. In addition, faults could be predicted earliest when the angle between the direction of tunnel advance and the strike of the fault was smallest.

• Journal of Aerospace System Engineering
• /
• v.8 no.4
• /
• pp.24-31
• /
• 2014

The modern version of aircrafts is allowed to guarantee the superior handing qualities within the entire flight envelope by imposing the adequate stability and flying qualities on a target aircraft through the various techniques of flight control law design. Generally, the flight control law of the aircraft in service applies the various techniques of the verified control algorithm, such as dynamic inversion and eigenstructure assignment. The supersonic trainer employs the RSS(Relaxed Static Stability) concept in order to improve the aerodynamic performance in longitudinal axis and the longitudinal control laws employ the dynamic inversion with proportional-plus-integral control method. And, lateral-directional control laws employ the blended roll system of both beta-betadot feedback and simple roll rate feedback with proportional control method in order to guarantee aircraft stability. In this paper, the lateral-directional flight control law is designed by applying dynamic inversion control technique as a different method from the current supersonic trainer control technique, where the roll rate command system is designed at the lateral axis for the rapid response characteristics, and the sideslip command system is adopted at the directional axis for stability augmentation. The dynamic inversion of a simple 1st order model is applied. And this designed flight control law is confirmed to satisfy the requirement presented from the military specification. This study is expected to contribute to design the flight control law of KF-X(Korean Fighter eXperimental) which will proceed into the full-scale development in the near future.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.34.6-34
• /
• 2002

1. Introduction 2. System Configuration 2.1 Control System 2.1.1 Longitudinal control 2.1.2 Lateral control 2.2 Sensor System 2.2.1 Photo interrupt 2.2.2 Ultrasonic sensor 2.3 Vision system 2.4 Communication system 2.4.1 Data communication 2.4.2 Image Communication 3. Test and Result 3.1 Vision test 3.2 Ultrasonic sensor test 4. Conculsion. Acknowledgment References.