• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.287-293
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• 2015

With the rise in oil prices and ongoing concerns about environment, there is an increased amount of interest in automated manual transmission (AMT) vehicles. Torque control in an AMT vehicle is attained by controlling the displacement of the dry-type clutch's actuator. To provide good ride comfort akin to that of an automatic transmission vehicle, the clutch control is vital to an AMT vehicle. In this study, a method of obtaining the clutch torque from a dynamometer test is devised. This method is able to identify the relationship between the displacement of the clutch actuator and the clutch torque. A simulator for estimating the performance of an AMT vehicle is developed using MATLAB Simulink. The results obtained from both the vehicle and simulation exhibit a similar trend.

• International Journal of Automotive Technology
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• v.7 no.2
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• pp.145-154
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• 2006

In the companion paper, the composition and structure of the MATDYMO (Multi-Agent for Traffic Simulation with Vehicle Dynamic Model) were proposed. MATDYMO consists of the road management system, the vehicle motion control system, the driver management system, and the integration control system. Among these systems, the road management system and the integration control system were discussed In the companion paper. In this paper, the vehicle motion control system and the driver management system are discussed. The driver management system constructs the driver agent capable of having different driving styles ranging from slow and careful driving to fast and aggressive driving through the yielding index and passing index. According to these indices, the agents pass or yield their lane for other vehicles; the driver management system constructs the vehicle agents capable of representing the physical vehicle itself. A vehicle agent shows its behavior according to its dynamic characteristics. The vehicle agent contains the nonlinear subcomponents of engine, torque converter, automatic transmission, and wheels. The simulation is conducted for an interrupted flow model and its results are verified by comparison with the results from a commercial software, TRANSYT-7F. The interrupted flow model simulation is implemented for three cases. The first case analyzes the agents' behaviors in the interrupted flow model and it confirms that the agent's behavior could characterize the diversity of human behavior and vehicle well through every rule and communication frameworks. The second case analyzes the traffic signals changed at different intervals and as the acceleration rate changed. The third case analyzes the effects of the traffic signals and traffic volume. The results of these analyses showed that the change of the traffic state was closely related with the vehicle acceleration rate, traffic volume, and the traffic signal interval between intersections. These simulations confirmed that MATDYMO can represent the real traffic condition of the interrupted flow model. At the current stage of development, MATDYMO shows great promise and has significant implications on future traffic state forecasting research.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.89-97
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• 2014

As the digital control technologies in automotive industry have advanced, electronic control units(ECUs) play a key-role to improve system performance. Transmission control unit(TCU) is a shifting controller for automatic transmission of which major functions are to determine the shift and manage the shifting process considering the various sensor signal on transmission and driver's commands. As with any ECU in vehicle, TCU performs complex algorithms such as shift control, diagnostic and failsafe functions. However, firmware design analysis is hardly possible by the reverse engineering due to code protection. Transmission simulator is a hardware-in-the-loop simulator which enables TCU to work in normal mode by simulating the electrical signal of TCU interface. In this research, diagnosis and failsafe algorithm implemented on commercialized TCU is analyzed by using the transmission simulator that is developed for wheel loader construction vehicle. This paper gives various experimental results on the proportional solenoid current trajectories for different operating modes, error detection criterion and limphome mode gears for all the possible cases of clutch malfunction. The derived results for conventional TCU can be applied to the development of inherent TCU algorithms and the transmission simulator can also be utilized for the test of TCU to be developed.

• Journal of Drive and Control
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• v.17 no.3
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• pp.47-56
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• 2020

As a shift control of automatic transmission was managed with the electronic control unit (ECU), shift quality which is a measure of shift shock during gear change has markedly improved. However, the initial clutch pressure control of the clutch filling phase should continue to rely on the predetermined control input since the input and output speeds are unchanged until the shifting process attains the inertia phase. It is critical to minimize the clutch response time and control the clutch pressure accurately at the end of clutch fill to achieve quick shift response and smoothness. Advanced transmission companies have adopted an auto calibration method which establishes the databases for the clutch piston fill-up attributes and the frictional characteristics of the disks. In this study, a distinctive auto calibration algorithm for forklift transmission under development is proposed and verified with the real-vehicle test. The experimental calibration results showed consistent turbine dynamics at the initial stage of shifts with the properly calibrated clutch-fill control parameters. By using this technique, it is necessary to finalize the shift control for the various operation conditions.

• Journal of Drive and Control
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• v.19 no.2
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• pp.17-26
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• 2022

Recently, automatic transmissions caused a good improvement in the shift quality of a forklift. An advanced shift control algorithm, which was based on TCU firmware, was applied with embedded control technology and microcontrollers. In the clutch-to-clutch shifting, one friction element is released and the other friction element is activated. During this process, if the release and application timings are not synchronized, an overrun or tie-up occurs and ultimately leads to a shift shock. The TCU, which measures only the speed of the forklift, inevitably applies the open-loop shift control. In this situation, the speed ratio does not change during the clutch fill. The torque phase occurs until the clutch is disengaged. In this study, an offline shift logic of the learning control was proposed. It induced a synchronous shift when the learning control progressed. During this process, the reference current trajectory of the release clutch was corrected and applied to the next upshift. We considered the results of the overrun/tie-up characteristics of the upshift performed immediately before. The vehicle test proved that the deviation in shift quality, which was caused by the difference in the mechanical characteristics of the clutch, could be improved by the learning control.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.391-393
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• 2005

Automatic guided vehicle(AGV) in the factory has an important role to advance the flexible manufacturing system. In this paper, we propose a novel object-transportation control algorithm of cooperative AGV systems to apply decentralized control scheme based on virtual-passivity. It is shown that the cooperative AGV systems ensure stability and the convergence to scaled multiple of each desired velocity field for multiple AGV systems. Finally, the application of proposed virtual passivity-based decentralized control algorithm via system augmentation is applied to be the tracking a circle. Also. the simulation results for the object-transportation by two AGV systems illustrate the validity of the proposed control scheme.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.6
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• pp.261-263
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• 2006

Automatic guided vehicle(AGV) in the factory has an important role to advance the flexible manufacturing system. In this paper, we propose a novel object-transportation control algorithm of cooperative AGV systems to apply decentralized control scheme based on virtual-passivity. It is shown that the cooperative AGV systems ensure stability and the convergence to scaled multiple of each desired velocity field for multiple AGV systems. Finally, the application of p reposed virtual passivity-based decentralized control algorithm via system augmentation is applied to be the tracking a circle. Also, the simulation results for the object-transportation by two AGV systems illustrate the validity of the proposed control scheme.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.831-835
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• 2016

In this paper, a dual-channel feed-forward transimpedance(TIA) array is realized in a standard $0.18-{\mu}m$ CMOS technology which exploits automatic gain control function to provide 40-dB input dynamic range for either detecting targets nearby or sensing imminent danger situations. Compared to the previously reported conventional feed-forward TIA, the proposed automatic-gain-control feed-forward TIA(AFF-TIA) extends the input dynamic range 25 dB wider by employing a 4-level automatic gain control circuit. Measured results demonstrate the linearly varying transimpedance gain of 47 to $72dB{\Omega}$, input dynamic range of 1:100, the bandwidth of $${\geq_-}670MHz$$, the equivalent input referred noise current spectral density of 6.9 pA/${\surd}$HZ, the maximum sensitivity of -26.8 dBm for $10^{-12}BER$, and the power consumption of 27.6 mW from a single 1.8-V supply. The dual-channel chip occupies the area of $1.0{\times}0.73mm^2$ including I/O pads.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.148.5-148
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• 2001

In this report, an adaptive flight control law based on a linear-parameter-varying (LPV) model is presented for a flight control system. The control system is designed to track an output of a vehicle to a reference signal from the guidance system, which generates a reference flight path. The proposed adaptive control law adjusts the controller gains continuously on line as flight conditions change. The obtained adaptive controller guarantees global stability over a wide flight envelope. Computer simulation involving six-degree-of-freedom nonlinear flight dynamics is applied to Japan´s automatic landing flight experimental vehicle (ALFLEX) to examine the effectiveness of the proposed adaptive flight control law.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.6
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• pp.502-509
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• 2005

In this paper, a 4-wheel vehicle model including the effects of tire slip was considered, along with variable parameter sliding control, in order to improve the performance of the vehicle longitudinal response. The variable sliding parameter is made to be proportional to the square root of the pressure derivative at the wheel, in order to compensate for large pressure changes in the brake cylinder. A typical tire force-relative slip curve for dry road conditions was used to generate an analytical tire force-relative slip function, and an antilock sliding control process based on the analytical tire force-relative slip function was used. A retrofitted brake system, with the pushrod force as the end control parameter, was employed, and an average decay function was used to suppress the simulation oscillations. The simulation results indicate that the velocity and spacing errors were slightly larger than those obtained when the wheel slip effect was not considered, that the spacing errors of the lead and follower were insensitive to the adhesion coefficient up to the critical wheel slip value, and that the limit for the antilock control under non-constant adhesion road conditions was determined by the minimum value of the equivalent adhesion coefficient.