• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.161-167
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• 2001

This paper presents an approach to nonlinear engine idle controller and intake manifold absolute pressure(MAP) observer based on mean torque production model. A stable engine idle speed is important in that the unstable engine Idle mode can make engine to drooping or stall state. A sliding fuzzy controller has been designed to control engine idle speed under load disturbance. A sliding observer is also developed to estimate the intake manifold absolute pressure and compared with the actual MAP sensor value. The sliding mode observer has shown good robustness and good tracking performance. The inputs of sliding fuzzy controller are the errors of rpm and MAP. The output is a duty cycle(DC) for driving a idle speed control valve(ISCV).

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3187-3188
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• 2000

Based on fuzzy control algorithm this paper constructed fuzzy controller for automated vehicles. For passenger's convenience especially comfortability controller need to reduce the frequency of input variable's changing. So we established membership functions for comfortability as well as speed following. It made possible to control comfortability directly. To demonstration the efficiency of fuzzy controller, we carried out simulation with a automobile's transfer function. Also we compared the difference of input variable. By comparing two controller's response, we can confirm the merit of fuzzy controller about comfortability. Fuzzy controller can reduce input changing frequency.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.33-38
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• 2003

This paper describes control principles of the piezoelectric ultrasonic motor which is operated by the ultrasonic vibration generated by the piezoelectric element. The piezoelectric ultrasonic motor has excellent characteristics such as compact size, noiseless motion, low speed, high torque and controllability, and has been recently applied for the practical utilization in industrial, consumer, medical and automotive fields. In this paper, the design of two-phase push-pull inverter for driving the piezoelectric ultrasonic motor is described, and a new control method of automatic resonant frequency tracking using PLL(Phase-Locked Loop) technique is mainly presented. the experimental results by this inverter system for driving the piezoelectric ultrasonic motor are illustrated herein. The inverter system with PLL technique improved the speed stability of the piezoelectric ultrasonic motor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.703-707
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• 2007

The line pressure control system for an automotive transmission in which a bleed type variable force solenoid(VFS) is applied, has been constructed and experimentally investigated. The hydraulic circuit of the system includes a line pressure control valve, a reducing valve, an accumulator, various orifices and a VFS. Static and dynamic responses of the throttle and line pressure have been monitored and discussed for various test conditions.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.2
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• pp.146-150
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• 2009

An Intelligent active roll angle controller design algorithm is discussed. The detailed mathematical formulation and analysis are discussed, and then modeling and design method for active roll angle controller are presented. This paper proposes a design method based upon intelligent robust controller design algorithm to control actively roll angle for improving cornering performance problems. The intelligent robust controller is designed for steady speed driving vehicle system model with representation of steering angle and yaw angular velocity parameters for cornering stability. And the detailed formulation and analysis for the objective vehicle system are investigated.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1132-1133
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• 2007

A circuit-domain model of PWM inverter provides accurate simulation results in consideration of detail switching characteristics. Although, a huge amount of computation time is demanded for the simulation results of several ten seconds, which is the required time to analyze system behaviors or control performances of Electric Power Steering(EPS) on real drive condition. This paper describes the nonlinear inverter model for fast dynamic simulation of EPS without the PWM concept through analyzing the effect of nonlinear switching characteristics like dead time, forward voltage drop and conduction resistance. Some inverter models including proposed model are compared from two standpoints which are computation time and accuracy. The comparison results show the usefulness of the developed model in order to develop the control algorithm through the fast prediction of system behaviors.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.405-410
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• 2006

This paper presents a control algorithm of supply and exhaust diffusers by recognizing a contaminant source location. CFD analysis has been conducted to calculate steady state airflow and concentration distributions in a model room, which has two supply and two exhaust openings on the ceiling. Calculations have been performed for five cases out of nine different ventilation modes by combining on/off control of the supply and exhaust openings. Local mean residual life times are obtained and compared at 9 internal points for each ventilation case. Depending on the contaminant source location, the ventilation system is operated at an optimum ventilation mode, which can results in maximum exhaust performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1305-1310
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• 2012

The performance of a system can be affected by the variance of noise factors, which arise owing to uncertainties of the material properties and environmental factors acting on the system. For robust design optimization of the system performance, it is necessary to minimize the effect of the variance of the noise factors that are impossible to control. However, present robust design techniques consider the variation of design factors, and not the noise factors, as being important. Furthermore, it is necessary to assume a normal distribution; however, a normal distribution is often not suitable to estimate the variations. In this study, a robust design technique is proposed to consider the variation of noise factors that are estimated as non-normal distributions in a real experiment. As an example of an engineering problem, a deep-sea manganese nodule miner tracked vehicle is used to demonstrate the feasibility of the proposed method.

• Journal of Technology Innovation
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• v.23 no.3
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• pp.287-316
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• 2015

The trend of R&D in automotive electronics industry is shifting towards ECU(Electronic Control Units) based on softwares which requires technology convergence to accommodate customers' requests on safety and convenience. The trend requires systemized R&D paradigm which reflects increased role of softwares. As the softwares became the core components in automotive innovation, there has been wide range of efforts to introduce software R&D processes and methodologies such as CMMI, A-SPICE and ISO-26262 etc. However, R&D departments in the industry fields are confronted with conflicts which arise from discrepancies among the individual process. In this study, we focus on suggesting our integrated and systematic R&D process with the aim of alleviating the conflicts and confusions. For this purpose, we analyze the cases of Korean automotive electronics companies to compare various R&D processes in the field and their relationships. Based on the analysis, we derive and suggest our model of R&D process which effectively integrate ISO/TS-16949 for manufacturing quality and CMMI, A-SPICE, ISO-26262 for system with softwares.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.91-99
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• 2014

The common-rail injectors are the most critical component of the CRDI diesel engines that dominantly affect engine performances through high pressure injection with exact control. Thus, from now on the advanced combustion technologies for common-rail diesel injection engine require high performance fuel injectors. Accordingly, the previous studies on the numerical and experimental analysis of the diesel injector have focused on a optimum geometry to induce proper injection rate. In this study, computational predictions of performance of the diesel injector have been performed to evaluate internal flow characteristics for various needle lift and the spray pattern at the nozzle exit. To our knowledge, three-dimensional computational fluid dynamics (CFD) model of the internal flow passage of an entire injector duct including injection and return routes has never been studied. In this study, major design parameters concerning internal routes in the injector are optimized by using a CFD analysis and Response Surface Method (RSM). The computational prediction of the internal flow characteristics of the common-rail diesel injector was carried out by using STAR-CCM+7.06 code. In this work, computations were carried out under the assumption that the internal flow passage is a steady-state condition at the maximum needle lift. The design parameters are optimized by using the L16 orthogonal array and polynomial regression, local-approximation characteristics of RSM. Meanwhile, the optimum values are confirmed to be valid in 95% confidence and 5% significance level through analysis of variance (ANOVA). In addition, optimal design and prototype design were confirmed by calculating the injection quantities, resulting in the improvement of the injection performance by more than 54%.