• Advances in aircraft and spacecraft science
• /
• v.10 no.1
• /
• pp.1-18
• /
• 2023

This paper investigates the integrated control of an air-breathing hypersonic vehicle considering the safety of propulsion system under acceleration. First, the vehicle/engine coupling model that contains a control-oriented vehicle model and a quasi-one-dimensional dual-mode scramjet model is established. Next, the coupling process of the integrated control system is introduced in detail. Based on the coupling model, the integrated control framework is studied and an integrated control system including acceleration command generator, vehicle attitude control loop and engine multivariable control loop is discussed. Then, the effectiveness and superiority of the integrated control system are verified through the comparison of normal case and limiting case of an air-breathing hypersonic scramjet coupling model. Finally, the main results show that under normal acceleration case and limiting acceleration case, the integrated control system can track the altitude and speed of the vehicle extremely well and adjust the angle deflection of elevator to offset the thrust moment to maintain the attitude stability of the vehicle, while assigning the two-stage fuel equivalent ratio to meet the thrust performance and safety margin of the engine. Meanwhile, the high-acceleration requirement of the air-breathing hypersonic vehicle makes the propulsion system operating closer to the extreme dangerous conditions. The above contents demonstrate that considering the propulsion system safety will make integrated control system more real and meaningful.

• Journal of Sensor Science and Technology
• /
• v.12 no.6
• /
• pp.265-272
• /
• 2003

This paper describes anodic bonding characteristics of MLCA (Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100%, input power $1\;W/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA and Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-0.08 %FS. Moreover, any damages or separation of MLCA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MLCA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.4
• /
• pp.81-90
• /
• 2022

In this study, for one-way concrete slabs, the flexural strength, deflection, and crack width according to the amount of reinforcing bars were compared for the cases of using steel reinforcing bars and CFRP reinforcing bars. Critical performance dominating the flexural design was investigated and how to design the CFRP-reinforced concrete slab with efficiency was also discussed. It was found that CFRP-reinforced concrete slabs could achieve greater design flexural strength with the same amount of reinforcing bars compared to those using steel rebar, while deflection and crack width were relatively much larger. In concrete slabs using CFRP reinforcing bars, it was confirmed that the maximum crack width acts as a dominant factor in the design. For more efficient flexural design, it is necessary to mitigate the allowable crack width to 0.7 mm and to apply smaller diameter reinforcing bars to control the crack width.

• Structural Engineering and Mechanics
• /
• v.88 no.1
• /
• pp.53-65
• /
• 2023

With the gradual implementation of long-span suspension bridges into high-speed railway operations, the main beam's bending stiffness contribution to the live load response permanently grows. Since another critical control parameter of railway suspension bridges is the beam-end rotation angle, it should not be ignored by treating the main beam deflection as the only deformation response. To this end, the current study refines the existing method of the main cable shape and simply supported beam bending moment analogy. The bending stiffness of the main beam is considered, and the main beam's analytical expressions of deflection and rotation angle in the whole span are obtained using the cable-beam deformation coordination relationship. Taking a railway suspension bridge as an example, the effectiveness and accuracy of the proposed analytical method are verified by the finite element method (FEM). Comparison of the results by FEM and the analytical method ignoring the main beam stiffness revealed that the bending stiffness of the main beam strongly contributed to the live load response. Under the same live load, as the main beam stiffness increases, the overall deformation of the structure decreases, and the reduction is particularly noticeable at locations with original larger deformations. When the main beam stiffness is increased to a certain extent, the stiffening effect is no longer pronounced.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.593-596
• /
• 1999

Steel fibers are added to concrete to improve energy absorption, impact resistance and apparent ductility, and to provide crack resistance and crack control. This study is to investigate the toughness index and post-crack equivalent tensile strength of steel fiber reinforced concrete properties on the load-deflection behaviors of the steel fiber reinforced concrete beam model specimens.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.369-372
• /
• 2006

In this paper, analysis method of HPFRCC is proposed as predicting properties flexural behavior. For analyzing HPFRCC beam, properties of strain-hardening, multiple cracking, and crack spacing control are considered as non-homogeneous material properties of the beam. This paper focused on the deflection, maximum moment of the flexural beam, distribution of crack width with the monte carlo simulation.

• Proceedings of the Optical Society of Korea Conference
• /
• 1998.08a
• /
• pp.170-171
• /
• 1998

Here are proposed the tunable laser for optical memory which uses the acousto-optic deflector. This laser includes the acousto-optic deflector in the Littrow mount configuration so that we may control the beam deflection by means of the induced RF. Consequently, we can achieve the higher speed and accuracy to compare with the Littrow monut configuration only.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.351-354
• /
• 2002

The F!T tube is a new type of CRT without a shadow mask. Correct color reproduction is performed by an electronic system that measures the landing positions of the electron beams and corrects through a dedicated deflection system. This paper describes in detail the position sensor and some of the electronics needed to build a functional control system. The principle has been shown in single- and triple-beam 17" and 32" tubes, of which results are included.

• International Journal of Control, Automation, and Systems
• /
• v.5 no.4
• /
• pp.410-418
• /
• 2007

For the purpose of fault detection of the primary control surface, real-time estimation of the longitudinal stability and control derivatives of the DURUMI-II using the flight data is considered in this paper. The DURUM-II, a research UAV developed by KARI, is designed to have split control surfaces for the redundancy and to guarantee safety during the fault mode flight test. For fault mode analysis, the right elevator was deliberately fixed to the specified deflection condition. This study also mentions how to implement the multi-step control input efficiently, and how to switch between the normal mode and the fault mode during the flight test. As a realtime parameter estimation technique, Fourier transform regression method was used and the estimated data was compared with the results of the analytical method and the other available method. The aerodynamic derivatives estimated from the normal mode flight data and the fault mode data are compared and the possibility to detect the elevator fault by monitoring the control derivative estimated in real time by the computer onboard was discussed.

• Journal of Korean Institute of Industrial Engineers
• /
• v.42 no.5
• /
• pp.360-369
• /
• 2016

This study attempted to identify the effect of the panel stiffness on the customers' affect, which was not addressed in the research field of affective engineering. For this, this study derived four affects related to the panel stiffness from literature and pre-experiment : hardness, deform consistency, thickness and satisfaction and prepared a questionnaire to evaluate the affects of the panel. In the experiment, 54 adults in the age of 20~50 participated and evaluated the affects of hood, front and rear door for nine full size and luxury sedans by pressing the panels with their hands. As results, participants' affect for the panels were significantly different depending on the force-deflection curves of them, and the subjects' satisfaction of the panels increased as the slope of the curve (stiffness) increases. In addition, it was found that the subjects evaluated the panel with the pressing force up to 14kgf. The findings of the study can be used to increase and control the affective quality of exterior panels on passenger cars.