• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.654-662
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• 1998

Shift quality of an automatic transmission in a vehicle is mainly affected by transient pressures in the hydraulic system during shifting. In this study, dynamic modelings of the hydraulic system and the power train of an automatic transmission are made systematically by a bond-graph method. The dynamic characteristics of the line pressures and clutch/brake pressures during shiftings are investigated by simulations and verified by experiments. The effects of clutch/brake pressures on the shift torque are also investigated through driving simulation.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.133-136
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• 2001

This paper partially presents a Hierachical neural network architecture for providing the intelligent control of complex Automatic Transmission(AJT) system which is usually nonlinear and hard to model mathematically. It consists of the module to apply or release an engine brake at the slope and that to judge the intention of the driver. The HNN architecture simplifies the structure of the overall system and is efficient for the learning time. This paper describes how the sub-neural networks of each module have been constructed and will compare the result of the intelligent hJT control to that of the conventional shift pattern.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.91-105
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• 1999

Dynamic simulation techniques are developed to analyze the shift characteristics of vehicle powertraisn with automatic transmission. In this study, the mathematical modeling of powertrain components such as engine , clutch system, planetary gear system and road load , is presented for the simulation. The clutch engagement condition, which determines the degree of freedom for the system, is also proposed .By using a detailed nonlinear model of torque converter, it is possibile to accurately analyze the extremely transient state such as the shift. Dynamo-based experiments are carried out to prove the validity of the proposed simulation techniques. Using the developed simulation program, the effects of the dynamic design variables and the control conditions , focused on the shift, are evaluated to improve the driving comforability.

• Journal of Drive and Control
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• v.10 no.4
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• pp.7-13
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• 2013

A tractor is a farm vehicle that is designed to provide a high tractive effort at low speed. It is used for versatile agricultural tasks such as hauling a trailer, tillage, mowing and construction work. As the intensity of work increases, tractors equipped with automatic transmission become popular due to the work convenience. Though manual and power shuttle transmissions are produced by domestic corporations, development for full-automatic power shift transmissions has never been challenged, and so related technology level is quite low. This paper gives a survey of the automatic transmissions from advanced foreign company, which includes layout of gear train, the way hydraulics controls clutches and brakes, electronic control system. The results are expected to be utilized as a basis in the development of original power train design for tractor.

• Fire Science and Engineering
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• v.20 no.1 s.61
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• pp.23-27
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• 2006

With the development of the today's advanced industry civilization, We are always inhering a safety frigidity about disasters of various kinds when and where we may happen. The fires and disasters to be enlarged day by day are reported everyday through the mass communication. Therefore, a prevention countermeasure about the every kind fire and disaster is above all important along the social and the days requirement. As a kind of such countermeasure, this paper is proposed about automatic transmission system of disasters alarm by using wire and wireless communication network. The automatic transmission system prevents the unexpected fire or disaster from a sudden occurrence at the house, industrial field or at the place without the human. The proposed system has the characteristic of high precision and high response speed comparing with conventional system. Also, as the proposed system is small size and lightweight, the users have economic advantage and simply install the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.623-629
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• 2003

This study is about the development of a system related to the CATV network. It intends to develop an automatically centralized Headend system and a distributive system to remove the ineffectiveness of the established manual system. To achieve this goal, we took a pan of bandwidth, which is not used for the transmission of video signals in the established frequency bandwidth, and used it for the transmission and receiver of controlling signals. By this way we could design a system of transmission and receiver and a automatic distributive system. We developed an information management system for the 9600bps CATV using RS-232 of forward/backward communication and backward communication.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.484-487
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• 1997

In this paper a simulation program for the powertrain control of a gasoline engine with automatic transmission is presented, The object-oriented programming approach has been pursued, and MATLAB/ SIMULINK was adopted for its environment. The purpose of the paper is to demonstrate the programmability of a control system in the object-oriented fashion so that the transferability of the objects is guaranteed. The program developed in the paper was applied to a gasoline engine and the mathematical models used in the paper were just adopted from the literature. It is shown that the simulation results and real experimental results coincide well. Therefore, it is expected that the program or objects made in the paper are useful for the automotive engineers when they design a new engine/transmission system or modify a part of existing system.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.723-729
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• 2001

Electro-hydraulic shift control of a vehicle automatic transmission has been predominantly carried out via an open-loop control based on numerous time-consuming calibrations. Despite remarkable success in practice, the variations of system characteristics inevitably deteriorate the performance of the tuned open-loop controller. As a result, the controller parameters need to be continuously updated in order to maintain satisfactory shift quality. This paper presents a self-learning algorithm for automatic transmission shift control in a construction vehicle during inertia phase. First, an observer reconstructs the turbine acceleration signal (impossible to measure in a construction vehicle) from the readily accessible turbine speed measurement. Then, a control algorithm based on a quadratic function of the turbine acceleration is shown to guarantee the asymptotic convergence (within a specified target bound) of the error between the actual and the desired turbine accelerations. A Lyapunov argument plays a crucial role in deriving adaptive laws for control parameters. The simulation and hardware-in-the-loop simulation (HILS) studies show that the proposed algorithm actually delivers the promise of satisfactory performance despite the system characteristics variations and uncertainties.

• Journal of Biosystems Engineering
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• v.18 no.4
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• pp.305-316
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• 1993

Fuel efficiency in tractor operations dep6nds on the selection of transmission gears and upon the engine being operated at or near maximum torque much of time. The objective of this study was to develop automatic control systems for tractor transmission ratio and governor setting so that the engine is operated at or near maximum torque as much of time as possible. An indoor test unit, which can be used to simulate tractor operation, was built in order to investigate the system design parameters and test the performance of the control system designed. The test-unit consists of engine, gear-type transmission, dynamometer, and control systems for transmission ratio and engine speed. Governor setting lever was controlled by a step motor, and the clutch and transmission levers were controlled by hydraulic cylinders and solenoid valves. The control systems showed good time responses which are assumed to be suitable for optimal tractor operation. The time required for shifting gears from clutch disengagement to engagement was about 1 second, which is almost the same as that for manual shift. And the settling time for engine speed control system was about 5 to 6 seconds.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.3
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• pp.23-31
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• 2009

Counter shaft transmission is a popular automatic transmission power train in construction vehicles such as wheel loader and forklift. The gear train layout of counter shaft transmission is a very basic and important development stage because it affects the most of components design including hydraulic system and shift control algorithm, etc. This paper presents a design methodology for the gear train layout from the analysis of power flow path and clutch hook-up of the existing counter shaft transmission that is adopted in commercialized construction vehicles. Also, independent constraints for the meshed gear ratios are derived in order to realize forward 4-speed and reverse 3-speed gear ratio. The layout design principle proposed here was applied to the new original counter shaft transmission that is underdevelopment.