• Journal of Korean Society of Transportation
• /
• v.6 no.2
• /
• pp.49-56
• /
• 1988

Alternate use of lane at a signalized intersection is a quite different control of the operation of an intersection. This control introduces a new stop line and signal before the original stop line. All of the lanes between the two stop lines are used for left turn traffic or through traffic at a time. The purpose of the control is increasing the capacity of a n intersection without widening the approach width. this paper contains a study on the condition of a application, the proper distances between the two stop lines, the reasonable offsets(rear) to guarantee clearing the vehicles of previous phase, the comparison of approach capacity between the existing control and this control. The study results reveals that the offsets(rear) are rather stable showing the range(maximum value minus minimum value) of it's value does not exceed 3.6 seconds according to the field data. The approach capacity will be increased by 27%, 43%, 59%, 84% when the distances between the stop lines are 30.0m respectively. The control might have theoretical limitation to operate in practice. So an experimental application of the control at some suitable intersections prior to expanding it.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1991.10a
• /
• pp.77-89
• /
• 1991

One of the important problems concerning the efficient operation of an automated manufacturing system is the flow control problem. Most research papers about scheduling and control of a FMS consider fabrication, machining and assembly independently. In this paper an effective flow control strategy for a FMS with an assembly subsystem which may be called FMAS (Flexible Machining and Assembly System) is designed using the operation-oriented and, combined Push and Pull control method. The flow control system to be described here could meet production demands with a minimum makespan while satisfying assigned due-dates and keeping a low volume of work-in-process at the same time. The control mechanism also considers machine failures and rush jobs.

• Proceedings of the SAREK Conference
• /
• 2007.11a
• /
• pp.167-175
• /
• 2007

A predictive pulse control strategy as a means of improving the energy efficiency of radiant floor heating systems is explored. Experiments at the apartment with floor heating system are conducted to assess and compare the energy performance of the predictive pulse control strategy with an existing conventional control strategy. The Results showed that new suggested PPCM( Predictive Pulse Control Method) was available to decrease the gap of $1{\sim}1.5^{\circ}C$ between maximum and minimum indoor temperature of each rooms. Therefore PPCM method was favor to radiant floor heating system which have a delay time of 10-20 minutes for heat transfer by floor layers.

• Journal of the Korea Society for Simulation
• /
• v.14 no.3
• /
• pp.79-90
• /
• 2005

There are plenty of optimization models for the signal-system of a single intersection and area traffic. Some of those models are adopted for the real traffic signal control system. The simulators for a single crossroad have been developed, so that we could evaluate optimization models and traffic control systems. However, the simulators for the area traffic are still being developed. Therefore, there are many limitations in the analysis and evaluation for area traffic control system. The area traffic is consisted of several intersections which are very complicated and many traffic strategies are adopted for the control system. This paper features an effective area traffic control system based on the High Lever Architecture(HLA). In this paper, we discuss the design of HLA-based area traffic control simulation. We describe technical motivations for the HLA, the key elements of the architecture and how they are minimum and essential to the goal of reuse and interoperability. A distributed simulation with HLA/RTI provides stable and satisfactory experimental results. Moreover, the prototype traffic control system provides reliable accomplishment compared to the NETSIM and TRANSYT-7F models.

• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.1
• /
• pp.105-110
• /
• 2017

This paper introduces a heave compensation system for offshore crane when it subjected to unexpected disturbances such as ocean waves, tidal currents or winds and their external force. The dynamic model consists of a crane which is considered to behave in the same manner as a rigid body, a hydraulic driven winch, an elastic rope and a payload. To keep the payload from moving upwards and downwards, PD(Proportional-Derivative) control was applied by using linearization. In order to achieve a better performance, the sliding mode control and the nonlinear generalized predictive control algorithm was applied according to the time-delay. As a result, the oscillating amplitude of the payload was reduced by the control algorithm. Considering the time-delay involved in the system to be one second, nonlinear generalized predictive controller with a robust controller was a suitable control algorithm for this heave compensation system because it made the position of te payload reach the desired position with the minimum error. This paper presented a control algorithm using the robust control and its simulation results.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.1
• /
• pp.1-5
• /
• 2014

In this paper, we propose an optimal fixed-lag FIR (Finite-Impulse-Response) smoother for a class of discrete time-varying state-space signal models. The proposed fixed-lag FIR smoother is linear with respect to inputs and outputs on the recent finite horizon and estimates the delayed state so that the variance of the estimation error is minimized with the unbiased constraint. Since the proposed smoother is derived with system inputs, it can be adapted to feedback control system. Additionally, the proposed smoother can give more general solution than the optimal FIR filter, because it reduced to the optimal FIR filter by setting the fixed-lag size as zero. A numerical example is presented to illustrate the performance of the proposed smoother by comparing with an optimal FIR filter and a conventional fixed-lag Kalman smoother.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.1
• /
• pp.56-63
• /
• 2003

This paper studies that torque model considered with decaying phase back-EMF is different In conduction and commutation period and analyzes the torque pulsation components mathematically. In this paper, it is proposed a novel method to suppress torque pulsation due to commutation time. First, it propose commutation delay time control method, which is to compensate current slope of rising phase and decaying phase to control commutation time. Current ripple is minimized at non-commutating current and torque ripple is reduced below critical speed range that dc link voltage is the same as four times of back-EMF voltage. However, torque ripple still exists due to the relation with back-EMF and commutating current and it is increased on a large scale above critical speed range, especially. Secondly, proposed method is commutation time control, which is considered with torque pulsation due to the relation of back-EMF and commutating current. Through the proposed method, the torque pulsation can be minimized in the whole speed range as well as range over critical speed.

• The Transactions of the Korea Information Processing Society
• /
• v.1 no.3
• /
• pp.357-366
• /
• 1994

The IEEE 802.4 token bus has been widely accepted as the standard for factory local area networks. The priority option of the 802.4 standard supports multiple classes of traffic by using a set of timers to control information exchange. The performance of the 802.4 priority mechanism in industrial real time control is examined. A timer assignment technique is presented for such applications. The timers are set to satisfy the worst case access delay requirements of real time control applications. Other applications that are not time constrainted can be supported simultaneously. In fact under certain conditions, such applications can also be guaranteed a minimum bandwidth allocation. Simulation results are used to evaluate the timer assignment and utililization.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.9
• /
• pp.34-40
• /
• 1999

In order to establish the design technique of the robust current controller in d.c series wound motor driver system, this paper proposes a method of the compensated Bang-Bang current control using d.c series wound motor driver system under the improperly variable load to get minimum time for the torque control. The compensated Bang-Bang current controller structure is simpler than that of PID plus Bang-Bang controller. This paper shows that a general 16 bits microprocessor is efficiently used to implement such an algorithm. The calculation time of software is extremely small when compared with that of conventional PID plus Bang-Bang controller. Both nonlinear operating characteristics of digital switching elements and describing function methods are used for the analysis and synthesis. Real-time implementation of the compensated Bang-Bang current controller is achieved. The concept of design strategy of the control and the PWM waveform generation algorithms are presented in this paper.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.787-792
• /
• 1991

This paper proposes a steering control algorithm for non-holonomic mobile robots. The steering control algorithm is essential to navigate autonomous vehicles which employ comination of the dead reckoning and absolute sensor system such as a machine vison for detecting landmarks in order to estimate the current location of the mobile robot. The proposed algorithm is based on the minimum time BANG-BANG controller and curvature-continuity curve design method. In the BANG-BANG control scheme we introduce velocity/acceleration limiter to avoid any slippage of driving wheels. The proposed scheme is robot-independent and hence can be applied to various kinds of mobile robot or vehicles. To show the effectness of the proposed control algorithm, a series of computer simulations were conducted for two-wheel driven mobile robot.