• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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• pp.700-702
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• 2000

The new design methodology of a hybrid fuzzy controller by means of the genetic algorithms is presented. In fuzzy controller which has been widely applied and used. in order to construct the best fuzzy rules that include adjustment of fuzzy sets, a highly skilled techniques using trial and error are required. To deal with such a problem, first, a hybrid fuzzy controller(HFC) related to the optimal estimation of control parameters is proposed. The HFC combined a PID controller with a fuzzy controller concurrently produces the better output performance than any other controller from each control output in steady state and transient state. Second, a auto-tuning algorithms is presented to automatically improve the performance of hybrid fuzzy controller, utilizing the simplified reasoning method and genetic algorithms. In addition, to obtain scaling factors and PID Parameters of HFC using GA, three kinds of estimation modes such as basic, contraction, and expansion mode are effectively utilized. The HFCs are applied to the first-order second-order process with time-delay and DC motor Computer simulations are conducted at step input and the performances of systems are evaluated and also discussed from performance indices.

• 한국정밀공학회지
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• 제19권12호
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• pp.163-170
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• 2002

The quality of a precision product, in general, relies on the accuracy and precision of its manufacturing and inspection process. In many cases, the level of precision in the manufacturing and inspection system is also dependent on the positioning capability of tool with respect to the work piece in the process. Recently the positioning accuracy level has reached to the level of submicron and long range of motion is required. For example, for 1 GDARM lithography, 20nm accuracy and 300mm stroke needs. This paper refers to the lithography stage especially to fine stage. In this study, for long stroke and high accuracy, the dual servo system is proposed. For the coarse actuator, LDM (Linear DC Motor) is used and for fine one VCM is used. In this study, we propose the new structure of VCM for the fine actuator. It is 3 axis precision positioning stage for an aligner system. After we perform the optimal design of the stage to obtain the maximum force, which is related to the acceleration of the stage to accomplish throughput of product. And we controlled this fine stage with TDC. So we obtained 50nm resolution. So later more works will be done to obtain better accuracy.

• 한국기계가공학회지
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• 제4권2호
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• pp.37-42
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• 2005

Recently $6{\sigma}$ quality control is an most important strategy to many enterprises in order to be a top company in the world, because it is an excellent scientific method to achieve the best quality control for their management and products. SY company is a small and medium one that has the quality problem for a long time such as occurring cracks on the surface of commutator at his assembly line while being assembled a rotor shaft and commutator of DC motor. This research was started to improve this problem by $6{\sigma}$ process, and as the results of this study, first, to find three vital fews, second, to get an achievement of about 21% improvement for the fracture strength of commutator, and third, to be recognized to change into $6{\sigma}$ quality control in SY company.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.501-503
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• 1999

In this paper, the design method of a hybrid fuzzy controller with an optimal auto-tuning method is proposed. The conventional PID controller becomes so sensitive to the control environments and the change of parameters that the efficiency of its utility for the complex and nonlinear plant has been questioned in transient state. In this paper, first, a hybrid fuzzy logic controller(HFLC) is proposed. The control input of the system in the HFLC is a convex combination by a fuzzy variable of the FLC's output in transient state and the PID's output in steady state. Second, a powerful auto-tuning algorithm is presented to automatically improve the Performance of controller, utilizing the improved complex method and the genetic algorithm. The algorithm estimates automatically the optimal values of scaling factors and PID coefficients. Controllers are applied to the plants with time-delay and the DC servo motor Computer simulations are conducted at the step input and the system performances are evaluated in the ITAE.

• 대한기계학회논문집A
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• 제26권12호
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• pp.2598-2604
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• 2002

Robots that can move along the narrow and rough tube are very important as the request for the inspection increases. It is necessary for the inspection robots to have a capability to move successfully at even overturned situation and have a simple mechanism to reduce the unexpected failure possibility fer the successful completion of the given mission. Through this paper, the authors propose a novel and simple mechanism using a combination cam device to generate the locomotive motion of multi-legs. This robot uses one DC motor and one combination cam shaft to generate the locomotive motion and can move rough tubes without failure even at the overturned situation. The robot also shows enough fragging force fer the connected line that is very important for a wired inspection robot. Kinematics analysis to design the specification of the robot will be followed and several applications show this robot's potential capabilities.

• Journal of Advanced Marine Engineering and Technology
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• 제32권6호
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• pp.974-980
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• 2008

Generally. most of the physical systems affected by disturbance or incomplete knowledge are complex and highly nonlinear. To control under these circumstances. many researches are ongoing in modern control theory recently. But the researches need apparatuses. which can verify the controller for being not damaged the real plant. In this paper. therefore. a seesaw system is considered control system to analyze and apply the control theory. A seesaw system consists of a moving cart on the rail and seesaw frame made to demonstrate the effectiveness of the control theory. The system has balancing and positioning problems. and the driving force is applied on the DC motor of cart. but not on the pivot. The purpose of control is to maintain an equilibrium of seesaw frame in spite of an allowable disturbance. Computer simulations are given to illustrate the control performance of the proposed scheme.

• 제어로봇시스템학회논문지
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• 제2권3호
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• pp.181-187
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• 1996

A frictionless positioning device using cone-shaped active magnetic bearings(AMBs) is developed, which is driven by a brushless DC motor equipped with resolver. The cone-shaped AMB feature that the structure is simple and yet the five d.o.f. rotor motion is controlled by four magnet pairs. A linearized dynamic model, which accounts for the relationship between input voltage and output current in the cone-shaped magnet, is developed and the azimuth motion of the frictionless positioning device is modeled as the second order system. The feedback controller is designed by using linear quadratic regulator with integral action optimal control law so that the cone-shaped AMB system is stabilized and the frictionless positioning device gets the zero steady state. It is observed that the linearized dynamic model is adequate and the frictionless positioning device can achieve the tracking accuracy within the sensor resolution.

• 한국해양공학회지
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• 제16권1호
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• pp.64-70
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• 2002

This paper shows the results of the development of a small size of digital type continuous and intermittent welding auto-carriage based on microprocessor (Intel 80196KC) for welding process with long welding line. The developed welding auto-carriage loads welding torch and tracks welding line. It is an automaton largely used for welding process with a lot of long welding lines such as shipbuilding and structure. Most traditional auto-carriages have been developed based on analog circuit for open loop control. So this analog circuit welding auto-carriage cannon control welding speed. Specially welding auto-carriage for intermittent welding condition is so complicated and has the low precision of control performance in welding distance and non-welding distance. The auto-carriage developed in this paper has the following characteristics: It has not only functions of traditional carriage but also functions such as pseudo-welding process of big iron structures, intermittent welding in order to limit heat for welding thin plates, crater treatment of the final step of welding, acceleration at the initial step of welding and deceleration in the final step of welding. The main control board of auto-carriage, power supply system and DC motor drive wee developed and manufactured. The welding speed and the welding distance of the developed auto-carriage are controlled accurately by feedback control using photo-sensor. Hardware and software robust against the heat and noise produced on the welding process are developed.

• 전자공학회논문지
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• 제54권7호
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• pp.127-132
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• 2017

이 논문에서는 모델 기반 설계에 근거한 이륜 도립진자 로봇의 제어이득을 설계하고 NXT 마인드스톰과 RobotC 언어를 이용하여 수업에 활용 가능한 로봇을 제작 및 실험한다. 이륜 도립진자 로봇은 NXT 마인드스톰, 서보 직류전동기, 자이로 센서, 가속도 센서로 구성된다. 직류전동기에 내장된 엔코더를 이용하여 바퀴의 회전각을 검출하며 이동평균을 이용하여 바퀴의 회전각속도를 계산한다. 자이로 센서는 몸체의 피치 각속도를 측정하며 가속도 센서는 몸체의 피치 각도를 측정한다. 자이로와 가속도의 센서 융합을 통해 몸체 각도를 계산한다. 제어기 이득 요소는 휠 각도, 휠 각속도, 몸체 피치 각도, 몸체 피치 각속도에 대한 가중치이다. 이들 제어이득의 변화에 따른 도립진자 로봇의 변화를 실험하며 유용성을 확인한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.690-695
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• 2000

This article deals with the analytic results on the development and application of the Spherical CVT. The Spherical CVT is marked by its simple configuration, the infinite torque multiplication characteristic, and the smooth transitions between forward/neutral/reverse states of output speed. In this study, we describe the conceptual principles behind the Spherical CVT and some applications of it, which we developed recently. And, we propose the shifting algorithm based on the analytic consideration of CVT powertrain system. Contrary to conventional shifting algorithms using the OOL(optimal operating line) of the power source, the proposed shifting algorithm is represented as a $2^{nd}$ order equation in an explicit form, and it reveals the possibility of theoretic design of all optimal controller. As an example, we present numerical results that demonstrate the energy saving possible and the proposed shifting algorithm from the use of the Spherical CVT over standard reduction gear unit, using an ideal dc motor model.