• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.83-90
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• 2014

In this paper, we address the problem of designing and implementing an oil pump control system driven by a brushless DC (BLDC) motor. The proposed oil pump plays the role of providing fuel to the engine clutch and transmission of hybrid vehicles. Main consideration is given to enhancing response feature and accuracy of the oil pump by simplifying the controller that is driven by a BLDC motor under PWM voltage control, which is a standard control method for BLDC motors. The proposed control scheme also helps to increase efficiency and reliability of the oil pump system. To validate the performance of the proposed system, we conduct experiments on BLDC motor speed control and oil pump operations.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.92-99
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• 2013

Many automotive components for power generation such as motors and alternators have been widely using ferrite magnets. To ensure a high level of efficiency could be achieved in an alternator, the assembled magnets must be in good enough durability. Recently, some hairline cracks have been found on the magnet produced by manufacturers in Korea. Thus, there is an increasing concern that some of the magnets produced could cause further problems after being assembled in the alternator. Based on the standard alternator test (RS0008 : 2006), this paper has developed an accelerated failure-free test for magnets in alternator to demonstrate that assembled magnets will meet durability objective specified by the manufacturer. This guarantees the target life of the magnet with 90 percent reliability and 90 percent confidence level (R90C90). Temperature and rotation speed were selected as accelerated stress factors.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.188-200
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• 2005

Control of a multi-fingered robotic hand is usually based on the theoretical analysis for kinematics and dynamics of fingers and of object. However, the implementation of such analyses to robotic hands is difficult because of errors and uncertainties in the real situations. This article presents the control method for estimating the kinematic constraint of an unknown object by active sensing. The experimental system has a two-fingered robotic hand suspended vertically for manipulation in the vertical plane. The fingers with three degrees-of-freedom are driven by wires directly connected to voice-coil motors without reduction gears. The fingers are equipped with three-axis force sensors and with dynamic tactile sensors that detect slippage between the fingertip surfaces and the object. In order to make an accurate estimation for the kinematic constraint of the unknown object, i.e. the constraint direction and the constraint center, four kinds of the active sensing and feedback control algorithm were developed: two position-based algorithms and two force-based algorithms. Furthermore, the compound and effective algorithm was also developed by combining two algorithms. Force sensors are mainly used to adapt errors and uncertainties encountered during the constraint estimation. Several experimental results involving the motion of lifting a finger off an unknown object are presented.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.1
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• pp.1178-1186
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• 2001

This paper presents design and analysis of a 6 degree-of-freedom new haptic device using a par-allel mechanism for interfacing with virtual reality. The mechanism is composed of three pantograph mecha-misms that, driven by ground-fixed servomotors. stand perpendicularly to the base plate. Three spherical joints connect the top of the pantograph with connecting bars, and three revolute joint connect connecting bars with a mobile joystick handle. Forward and inverse kinematic analyses have been performed and the Jacobian matrix is derived by using the screw theroy. Performance indices such as GPI(Global Payload Index), GCI(Global Conditioning index), Traslation and Orientation workspaces, and Sensitivity are evaluated to find optimal pa-rameters in the design stage. The proposed haptic mechanism has better load capability than those of the ex-isting haptic mechanisms due to the fact that motors are fixed at the base. It has also wider orientation work-space mainly due to RRR type spherical joints.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1060-1065
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• 2003

This paper contributes to development of a new chip mounting head system for flip chip. Recently, the LDM(Linear DC Motor) has been widely used, because it has particular merits than the rotary type motors. In this paper, we proposed a macro/micro positioning system for force control of a chip mounting system. In the proposed macro/micro system, the macro actuator provide the system with a gross motion while the micro device yields fine tuned motion to reduce the harmful impact force that occurs between very small sized electronic parts and PCB surface. In order to prove the effectiveness of the proposed macro/micro chip mounting system, we compared the proposed chip mounting head with the conventional chip mounting head equipped with a macro actuator only. A series of experiments were executed under the mounting conditions of various access velocities and PCB stiffness. As a result of this study, a satisfactory voice coil actuator as the micro actuator has been developed, and its performance meet well the specifications desired for the design of the chip mounting head system and show good correspondence between theoretical analysis and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.552-557
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• 2004

This paper presents a disturbance observer based on an $H_{\infty}$ controller synthesis for the trajectory control of a hydraulic excavator. Compared to conventional robot manipulators driven by electrical motors, the hydraulic excavator has more nonlinear and coupled dynamics. In particular, the interactions between an excavation tool and the materials being excavated are unstructured and complex. In addition, its operating modes depend on working conditions, which make it difficult to not only derive the exact mathematical model but also design a controller systematically. In this study, the approximated linear model obtained through off-line system identification is used as nominal plant model for a disturbance observer. A disturbance observer based tracking controller which considers the effect of disturbance and model uncertainty is synthesized in $H_{\infty}$ frameworks. Simulation results are used to demonstrate the applicability of the proposed control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.622-627
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• 2003

The existing remote control system have some inherent disadvantage of direct control in the limit range. In some special cases, for example, a power apparatus, an unmanned factory, a nuclear factory, a security management system, the tele-operation is needed to control remote robot without limit space. This field is based on the Internet communication. Because the Internet is constructed all over the world. And it is possible that we control remote mobile robot in the long distance. In this paper, we developed a remote control system. This system is divided into two primary parts. These are local site and remote site. There are the moving robot and web server in the remote site and there is the robot control device in local site. The moving robot is moved by two stepper motors and the robot control device consists of SA-1100 micro controller and embedded Linux. And this controller is an embedded system. Public personal computer which is connected the Internet is used for the web server. The web server provides the mobile robot control interface program to the remote controller and captures the image for feedback information. In the whole system, a robot control device is connected with moving robot and web server through the Internet. So the operator can control the moving robot in the distance through the Internet.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.852-856
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• 2004

An induction motor is one of the most popular electrical apparatuses owing to its simple structure and robust construction. Parameter identification of the induction motor has long been researched either for a vector control technique or fault detection. Since vector control is a well-established technique for induction motor control, this paper concentrates on successive identification of physical parameters with on-load data for the purpose of condition monitoring and/or fault detection. For extracting six physical parameters from the on-load data in the framework of the induction motor state equation, unmeasured initial state values and profiles of load torque have to be estimated as well. However, the analytic optimization methods in general fail to estimate these auxiliary but significant parameters owing to the difficulty of obtaining their gradient information. In this paper, the univariate dynamic encoding algorithm for searches (uDEAS) newly developed is applied to the identification of whole unknown parameters in the mathematical equations of an induction motor with normal operating data. Profiles of identified parameters appear to be reasonable and therefore the proposed approach is available for fault diagnosis of induction motors by monitoring physical parameters.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.5
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• pp.825-833
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• 2020

Currently, the K-Water uses various valves that can be remotely controlled for optimal water management. Valve system fault can be classified into rotor defects, stator defects, bearing defects, and gear defects of induction motors. If the valve cannot be operated due to a gear fault, the water management operation can be greatly affected. For effective water management, there is an urgent need for preemptive repairs to determine whether gear is damaged through failure prediction diagnosis.. Recently, deep learning algorithms are being applied for valve failure diagnosis. However, the method currently applied has a disadvantage of attaching a vibration sensor to the valve. In this paper, propose a new algorithm to determine whether a fault exists using a convolutional neural network (CNN) based on the voltage and current information of the valve without additional sensor mounting. In particular, a normalized Lisasjous diagram was used to maximize the fault classification performance in the CNN-based diagnostic system.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.1
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• pp.41-50
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• 1999

The brushless DC motor is widely being used in unmanned factories for its easy maintenance and characteristics of controllability. In this paper, we designed a speed control servo system of a sinusoidal type bmshless DC motor which has high efficiency and usefulness in the industrial fields. This servo system is realized by a controller which is required for driving motors and a new auto-tuning PI control algorithm. The DSP(Digita1 Signal Processor) is adopted as a main controller and a sensor signal processor owing to its fast computational capability and suitable architecture. Also, the hardware PWnl(Pulse Width Modulation) current controller is implemented to pursue a speed command exactly. By experimental results, it is verified that the speed response is pursued fast after command value and the steady-state response is well converged for command value variation without overshoots.