• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.3
• /
• pp.201-208
• /
• 2002

In this paper, the control strategy of ratio changing system for a metal belt CVT adopting primary pressure regulation is developed, and the shirting performance of pressure regulating type CVT with the suggested control strategy is investigated. The control strategy suggested in this study is composed of 2 feedback loop, one is speed ratio feedback and the other is primary pressure feedback. The pressure feedback is adopted to ensure prohibiting a belt slip during transient period in a fast downshift mode. Simulation results show that the system with suggested control strategy gives appropriate response time and tracking Performance for upshift and also gives a proper primary pressure which can prohibit the belt slip. In addition, it is fecund that the given system has an acceptable servo property in tracking the target speed ratio and robustness for the disturbance of line pressure.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.4 s.97
• /
• pp.46-56
• /
• 1999

A semi-actively controlled impact system which adjusts an impulse exerted by the external impact is studies. The main control variables are internal pressure difference inside the cylinder and the shock absorber displacement while it travels. Compared to a conventional one so called a passive system with a variable orifice inside the cylinder, a semi-actively controlled system utilizes an external orifice controlled by a highly fast responding electrical proportional valve. This device overcomes the temperature and viscosity change due to continuous operating and keeps the desired pressure difference and displacement in every operation. In this article a new prototype impact system is designed and manufactured based on a semi-actively control system. Through computer simulations and experiments, we verify the possibility of controlling the shock absorber pressure and displacement. After investigating the control performance a modified semi-actively controlled system with better control performance is also proposed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.2
• /
• pp.150-158
• /
• 2002

Through experimental works, the damping force vibration problem was investigated, which results from valve and surge pressure in the oil return line of the hydraulic circuit of an active suspension system in a passenger cu. Experiments were carried out under passive system, where an orifice valve was closed and non-active system, where an orifice valve was opened, using a pressure control valve controlled by solenoid. The effects of parameters of the valve overlap and accumulator on smoothing surge pressure was elucidated. It was proved that the apparent variation of damping force due to the overlap amount of pressure control valve is the most important factor to control the damping force variation. The procedure of the experimental works shows the development process of a proportional pressure control valve in the hydraulics system of an active suspension system of passenger car.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.727-730
• /
• 1989

Tokyo dome is Japan's first air dome. The roof of the dome is supported by air pressure. The centralized control system (YOKOGAWA's DCS : CENTUM and YEWPACK) is applied to automatically regurate the air pressure. The control system acquires signals from sensors positioned throughout the stadium and operate 36 fans to blow air into the dome. Great emphasis is placed on the reliability and safety of the system.

• International Journal of Advanced Culture Technology
• /
• v.8 no.3
• /
• pp.254-259
• /
• 2020

The medical bed developed in this study is an electrically driven segmental keyboard. First describe the instrument of the segmental bed specially designed for pressure ulcer prevention, then the motor control system and pressure ulcer prevention operation of the bed. The main factor of pressure ulcer generation is displayed as body pressure x time, and when the keyboard falls, the body pressure becomes zero, and the pressure becomes higher than the threshold even if the body pressure is above the threshold, the pressure control algorithm has been developed. Therefore, using the proposed pressure control method, it has no particular ulcer occurred theoretically.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1672-1675
• /
• 2003

In this study, we developed full automation test system for pressure vessel. This pressure vessel containing oxygen, nitrogen and carbon is widely used in industrial field. The test items of pressure vessel are divided into three branches which is weight measurement, water-hydraulic, and leakage test. After leakage test is completed, cleaning and dry progress is carried out. And control system is consist of three controller which is PLC, monitoring system and database system. PLC is control all of system. Monitoring system measures weight, pressure, flow etc and display to all conditions. Database system stores tested data. we design system to control all test modules in communication by a second period with three control modules. Finally, we verified this system by field test.

• Journal of Power System Engineering
• /
• v.13 no.3
• /
• pp.59-64
• /
• 2009

This study presents a new approach to pressure control of a impression cylinder for roll coater which is a kind of face pressure control between blanket roll and impression roll. Roll-to-Roll method for printing is a very useful tool for mass production such as RFID elements, smart sensors and solar cell devices. In this study, a decupling control strategy of the roll coater which is a combination of a cylinder system, a dry system and two pressure regulators with two pneumatic cylinders was discussed. Also, the characteristics of component such as a pressure regulator having a pressure reducing function and the movement of a blanket roll and a impression cylinder were analyzed using the Matlab software. From this results, the techniques of a shock and a vibration reduction were suggested.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.10
• /
• pp.976-982
• /
• 2010

This paper proposes a novel type of pressure control mechanism which can apply to vehicle ABS (anti-lock braking system) utilizing the piezoactuator based valve system associated with the pressure modulator. As a first step, a flapper-nozzle of a pneumatic valve system is devised by integrating the piezoacuator to the flexible beam structure. The dynamic modeling of the valve system is then undertaken and subsequently the governing equation of pressure control is derived considering the pressure modulator. A sliding mode controller is designed in order to achieve accurate pressure tracking control in the presence of actuator uncertainty as well as input pressure variation. It is shown through computer simulation that an accurate pressure tracking for sinusoidal motion whose magnitude is 40 bar is achieved by utilizing the proposed pressure control mechanism.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.208-210
• /
• 2007

This paper proposes a novel direct instantaneous pressure control(DIPC) of hydraulic pump system with SR drive. And it has very simple control structure, because it doesn’t use any speed and torque control for adjusting pump pressure. The hysteresis band of pressure and proper switching rules can make the actual pump pressure to be constant with fast dynamic response. Therefore, the proposed DIPC method can control of hydraulic pump pressure steadily with fast dynamic response.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.6
• /
• pp.220-229
• /
• 2000

In the brake systems a proportioning valve which reduces the brake pressure at each wheel cylinder for anti-locking of rear wheels is closely related with the safety of vehicles. But, it is impossible for a present proportioning valve to exactly control brake pressure because mechanically it is an open loop control system. So, in this paper we describe a electronic brake pressure distribution system using a fuzzy controller in order to exactly control brake pressure using a close loop control system. The object of electronic brake pressure distribution system is to change an cut-in pressure and an valve slop of proportioning valve in order to obtain better good performance of brake system than with mechanical system.