• Journal of Auto-vehicle Safety Association
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• v.12 no.2
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• pp.27-32
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• 2020

This paper presents steering system requirements to ensure the stabilized lateral control of autonomous driving vehicles. The two main objectives of a lateral controller in autonomous vehicles are maintenance of vehicle stability and tracking of the desired path. Even if the desired steering angle is immediately determined by the upper level controller, the overall controller performance is greatly influenced by the specification of steering system actuators. Since one of the major inescapable traits that affects controller performance is the time delay of the steering actuator, our work is mainly focused on finding adequate parameters of high level control algorithm to compensate these response characteristics and guarantee vehicle stability. Actual vehicle steering angle response was obtained with Electric Power Steering (EPS) actuator test subject to various longitudinal velocity. Steering input and output response analysis was performed via MATLAB system identification toolbox. The use of system identification is advantageous since the transfer function of the system is conveniently obtained compared with methods that require actual mathematical modeling of the system. Simulation results of full vehicle model suggest that the obtained tuning parameter yields reduced oscillation and lateral error compared with other cases, thus enhancing path tracking performance.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.59-70
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• 2001

Typical low-level image processing tasks require thousands of operations per pixel for each input image. Traditional general-purpose computers are not capable of performing such tasks in real time. Yet important features of traditional computers are not exploited by low-level image processing tasks. Since storage requirements are limited to a small number of low-precision integer values per pixel, large hierarchical memory systems are not necessary. The mismatch between the demands of low-level image processing tasks and the characteristics of conventional computers motivates investigation of alternative architectures. The structure of the tasks suggests employing an array of processing elements, one per pixel, sharing instructions issued by a single controller. In this paper we implemented various image processing filtering using the format converter. Also, we realized from conventional gray image process to color image process. This design method is based on realized the large processor-per-pixel array by integrated circuit technology This format converter design has control path implementation efficiently, and can be utilize the high technology without complicated controller hardware.

• Journal of Power Electronics
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• v.12 no.2
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• pp.344-356
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• 2012

In recent years, multilevel technology has become an effective and practical solution in the field of moderate and high voltage applications. This paper discusses an APF with a three-level NPC inverter. Obviously, the application of such converter to APFs is hindered by the problem of the voltage unbalance of DC capacitors, which leads to system instability. This paper comprehensively analyzes the theoretical limitations of the neutral-point voltage balancing problem for tracking different harmonic currents utilizing current switching functions from the space vector PWM (SVPWM) point of view. The fluctuation of the neutral point caused by the load currents of certain order harmonic frequency is reported and quantified. Furthermore, this paper presents a close-loop digital control algorithm of the DC voltage for this APF. A PI controller regulates the DC voltage in the outer-loop controller. In the current-loop controller, this paper proposes a simple neutral-point voltage control method. The neutral-point voltage imbalance is restrained by selecting small vectors that will move the neutral-point voltage in the direction opposite the direction of the unbalance. The experiment results illustrate that the performance of the proposed approach is satisfactory.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.180-182
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• 2005

The current control using a conventional hysteresis controller of a STATCOM based on two level VSI (Voltage Source Inverter) has high switching frequency and variable modulation frequency. This will increase the switching loss. In addition, the current error is not strictly limited So, in this paper to reduce the switching frequency and to maintain the constant modulation frequency, a novel double band hysteresis current controller based on 3-level VSI is proposed. A conventional hysteresis current control and a novel hysteresis current control was tested with digital simulation and verified the advantage of the novel hysteresis current controller.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.774-782
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• 2001

In this paper, we propose a new approach to the autonomous and high-speed indoor navigation of wheeled mobile robots using hybrid system controller. The hierarchical structure of hybrid system presented consists of high-level reasoning process and the low-level motion control process and the environmental interaction. In a discrete event system, the discrete states are defined by the user-defined constraints and the reference motion commands are specified in the abstracted motions. The hybrid control system applied for the nonholonomic mobile robots can combine the motion planning and autonomous navigation with obstacle avoidance in the indoor navigation problem. For the evaluation of the proposed algorithm, the algorithm is implemented to the two-wheel driven mobile robot system. The experimental results show that the hybrid system approach is an effective method for the autonomous navigation in indoor environments.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.10
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• pp.859-866
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• 2001

Recently, fault injection techniques are used for evaluation of the fault coverage properties of safety-critical systems. This paper describes the TCN Fault Injector(TFI) implemented for TCN safety analysis. The implemented TFI injects network level faults to Intelligent MVB Controller that is designed for the Korean High Speed Train. With TFI, it can be verified whether the MVB controller meets TCN specification and its safety requirements.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1012-1017
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• 1993

In this paper, the instruction set and the architecture of a RISC processor for programmable logic controller is suggested. From the measurement of existing programs, the characteristics of ladder instructions are analyzed. The instruction set is defined so that the existing ladder program can be reused with simple translation. Because bit instructions controls the behavior of word instructions, the processor suits for high level language like SFC. Simulations show that the PLC with the suggested processor is twenty times faster than the PLC with the multi-purpose microprocessor.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.146.2-146
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• 2001

Recently, a need of non-industrial robot, such as service, medical, entertainment and house-keeping robot, has been increased. Therefore, the capability of robot which can do intelligent behavior like interaction with men and its environment become more prominent than the capability of executing simple repetitive task. To implement an intelligent robot which provides intelligent behavior, an effective system architecture including perception, learning, reasoning and action part is necessary. Control architectures for intelligent robot can be divided into two different classes. One is deliberative type controller which is applicate to high level intelligence like environment ...

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.24-29
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• 1991

RCCL(Robot Control C Library) is general purpose robot control language. It is programmed with C language and composed of C library. So it is well portable and supports sensor integration control and high level force control algorithms. We implemented RCCL on PUMA. We developed servo controller of DDC(Direct Digital Control). We used intel 8097BH one chip micro controller as CPU. One digital servo board controls three motors. Host computer is IBM PC 386DX-33 with RCCL.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.93-96
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• 2008

A transmitter (TX) leakage cancellation scheme using a Micro Controller Unit (MCU) is introduced. This paper highlights an adaptive anti-leakage signal generation via an MCU, which plays the key role in reducing the TX leakage signal level. High transmitter-to-receiver (TX-to-RX) isolation is verified with measurement results.