• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.357-363
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• 2005

The non-minimum phase characteristic of a flexible manipulator makes tracking control of its tip difficult. The level of the tip tracking performance of a flexible manipulator is significantly affected by the characteristics of the tip reference trajectory as well as the characteristics of the flexible manipulator system. This paper addresses the question of how to best specify a reference trajectory for the tip of a flexible manipulator to follow in order to achieve the objectives of reducing : tip tracking error, residual tip vibration, and the required actuation effort at the manipulator joint. A novel method of tip-based learning controller for the flexible manipulator system is proposed in the paper, where a model of the flexible manipulator system with a command shaping filter is used to generate a smooth and realizable tip reference trajectory for a tip-based learning controller.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.125-130
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• 1999

In this paper, it is presented a new technique to the design and real-time implementation of fuzzy control system based-on digital signal processors in order to improve the precision and robustness for system of industrial robot. Fuzzy control has emerged as one of the most active and fruitful areas for research in the applications of fuzzy set theory, especially in the real of industrial processes. In this thesis, a self-organizing fuzzy controller for the industrial robot manipulator with a actuator located at the base is studied. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variable of the controller, In the synthesis of a FLC, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult, SOFC is proposed for a hierarchical control structure consisting of basic level and high level that modify control rules.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.2
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• pp.131-140
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• 1992

The purpose of this study is to improve the performance of robot by providing visual function with robot and developing high-functioned controller and control program. The developed high-functioned controller and software have the better accuracy and flexibility in the movement of robot by complementing the existing robot controller and software problems. To provide visual function to robot, camera calibration, thresholding and contouring tools are also developed and applied in this study. These tools help robot recognize the central points and orientations of objects on work-bench.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.4
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• pp.593-608
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• 1995

In this study two issues are considered, one is to develop a pneumatic servomechanism using a direct-connected circuit between inlet and outlet, the other is to design two kinds of advanced controllers such as fuzzy and PID controllers for a fingering system. Besides, the application of the advanced controllers to the newly proposed servomechanism is presented. The procedure of this study is composed of following 6 steps : [Step 1] Structuring of a control system; [Step 2] Development of a pneumatic circuit for the servomechanism ; [Step 3] Characteristic analysis of the valve and cylinder systems ; [Step 4] Determination of optimal parameters of the PID controller ; [Step 5] Design of a fuzzy controller and parameter tuning; and, [Step 6] Experimental analysis of fuzzy and PID controllers. Experimental results show that the newly proposed pneumatic servomechanism has good performance and, not only the performance of the fuzzy controller is better than that of the PID controller but also the fuzzy controller fits well to the control of the pneumatic servomechanism.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.2
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• pp.1-7
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• 2008

This paper presents a method to design a repetitive controller that is robust to variations in the system parameters. The uncertain parameters are specified probabilistically by their probability distribution functions. Instead of working with the distribution functions directly, the repetitive controller is designed from a set of models that are generated from the specified probability functions. With this multiple-model design approach, any number of uncertain parameters that follow any type of distribution functions can be treated. furthermore, the controller is derived by minimizing a frequency-domain based cost function that produces monotonic convergence of the tracking error as a function of repetition number. Numerical illustrations show how the proposed multiple-model design method produces a repetitive controller that is significantly more robust than an optimal repetitive controller designed from a single nominal model of the system.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.371-379
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• 2006

Increasing requirements for the high quality of industrial robot performance made the vibration control issue very important because the vibration makes it difficult to achieve quick response of robot motion and may bring mechanical damage to the robot. This paper presents a vibration control solution for industrial robots which have flexible joints. The joint flexibility is modeled as a two-mass system. And we analyze the vibration problem of a classical P-PI controller when it used for the flexible joints of industrial robots. Then a state feedback controller is designed for vibration suppression of the two-mass system. Finally, a gain-scheduling method is designed for maintaining control performance in spite of the time-varying nature of each joint's load side inertia. Simulation and experimental results show effective vibration suppression and uniform properties in overshoot in spite of the variation of load. The result of this study can be applied to the appropriate gain manipulation of many other mechatronic devices which have the two-mass system with varying load side inertia.

• Management Science and Financial Engineering
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• v.3 no.2
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• pp.71-92
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• 1997

Developing FMS controllers has been a difficult problem largely because of the variety of the system configuration. The purpose of this paper is to develop a method of building an FMS controller. The controller consists of control module and execution module. A hierarchically layered structure of these modules is proposed. The control module generates abstract-level execution requested by identifying a set of activities that can be executed without creating any irregular state. The execution module transmits the requests to physical device controllers and reports back the completion of the requests to the control module. Both of these two modules use Petri Net-based models. In this paper, a controllable Petri Net model is automatically synthesized from declarative specifications provided by a user. An execution Petri Net model for the execution module is designed to ensure the consistency between the control module and the real target system. The controller operates in MMS on TCP/IP and UNIX environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.1-5
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• 2009

In this research, structural analysis was conducted by applying ANSYS commercial code in order to evaluate deflection quantitatively when each weight of tension controllers was centered and weights and moments on a controller controlling tension amounts was varied in a machinery manufacturing flexible flat cable. Based on the numerical structure analysis, stress, strain and amounts of maximum deformation were obtained and investigated structural validity and was reflected on design of the controller.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.257-262
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• 2002

A design method of a power controller for controlling the temperature adopted in RTP (rapid thermal processing) which uses the phase control method is presented. The power controller is fabricated by using the design method presented in this paper and is tested. As the results, the range of average voltage from the variable output is 0∼198.06 V and the control resolution is 48.356 mV (12 bit) at the range of the input signal (0∼10 V).

• Journal of Industrial Technology
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• v.31 no.B
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• pp.75-79
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• 2011

In this paper a new PFC Controller for 3-Phase Modular UPS(Uninterruptible Power Supplies) is proposed. The PFC circuit for 3-Phase Modular UPS is implemented using three 1-phase 3-level boost PFC circuits. To control DC output voltage, single voltage controller considering imbalance of two capacitor voltages and to regulate AC input current three independent current controllers are used in proposed PFC controller. By the proposed method, without additional hardware, THD(Total Harmonic Distortion) of input currents can be readily limited below 5% which is the harmonic current requirements by IEEE std. 519. Its validity is verified by simulations and experiments.