• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.865-874
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• 2019

A controller for an underwater glider is presented. Considered underwater glider is a torpedo-shaped autonomous underwater vehicle installing adjustable buoyancy bag and movable battery in it. The controller is composed of an LQR controller to maintain zigzag vertical movement for gliding and two PD controllers to control elevator/rudder angles. The LQR controller controls the pumping speed into the buoyancy bag and the moving speed to locate the battery. One of the PD controller controls the elevator angle to assist the LQR controller, and the other controls the rudder angle to adjust the direction of the underwater glider. A reduced order Luenberger observer is adopted to estimates the center of gravity of the glider and the buoyancy mass that are essential but cannot be measured. Mathematical simulation using Matlab proved the validity of the proposed controller to obtain better performance than conventional LQR only controller under the influence of sea current.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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• pp.189-195
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• 2005

This paper presents a new velocity estimation strategy for a non-salient permanent magnet synchronous motor drive without high frequency signal injection or special PWM pattern. This approach is based on the d-axis current regulator output voltage of the drive system, which contains the rotor position error information. The rotor velocity can be estimated through a rotor position tracking PI controller that controls the position error at zero. For zero and low speed operation, the PI gain of the rotor position tracking controller has a variable structure according to the estimated rotor velocity. Then, at zero speed, the rotor position and velocity have sluggish dynamics because the varying gains are very low in this region. In order to boost the bandwidth of the PI controller during zero speed, the loop recovery technique is applied to the control system. The PI tuning formulas are also derived by analyzing this control system by frequency domain specifications such as phase margin and bandwidth assignment.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2196-2199
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• 1997

In the industrial motor drive system, a shaft torsional vibration is often generated when a motor and a load are connected with a flexible shaft. This paper treats the vibration suppression control of such a system. In this paper, a control system design method using Linear Matrix Inequality (LMI), which is a tool for control design that replaces or complements Lyapunov-Riccati equations, is provided and a $H_{\infty}$ speed controller for a induction motor by LMI is proposed. In the $H_{\infty}$ speed controller, weights are used to satisfy tracking and disturbance rejection. Experimental results show the validity of the proposed $H_{\infty}$ speed controller by LMI, and this controller is compared with the state feedback controller.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.88-90
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• 2007

This paper is proposed high performance speed control using AFNN controller. The design of the speed controller based on adaptive fuzzy-neural networks(AFNN) controller that is implemented using fuzzy control and neural networks. The control performance of the AFNN controller is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1380-1384
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• 2015

The DC motor has the strong characteristics in the speed response, the system parameter variations and the external influence and is used as the speed controller with its good starting torque in the distributing industry. However development of the Microprocessor which is for high speed switching program can make better control system. This paper introduce to design of the high-effective DC motor controller that is using Software Bang-Bang Program of Fuzzy algorithm and to verify a PI controller and a Fuzzy controller.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.166-169
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• 2002

The purpose of this paper is to develop systematic analysis and automatic tuning rule of PID controller for industry servo applications. Considering the coupling of inner current control loop and speed loop delay, the target plant fit into second-order plus time delay model. Based on PID controller design for high-order plus known/unknown time delay plant model, some formulars are provided for the control gain calculation and system-based theoretical analysis is developed, and it also allows an automatic controller setup to benefit the inexperienced user. In addition, the proposed design rule gives uniformly satisfactory performance and the motor speed stays on a desired response curve with minimal oscillation and settling time. This approach can be applicable in conjunction with the cascaded control loop which is widely used in practice.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.9-15
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• 2008

In this paper, we suggest PI control with a predictive controller to progress both energy saving and coefficient of performance(COP) in a variable speed refrigeration system. The capacity and superheat are controlled simultaneously and independently by an inverter and an electronic expansion valve respectively for saving energy and improving COP in the system. The refrigeration system has long dead time in superheat inherently. The dead time makes the system difficult to achieve the satisfactory quick control response, especially superheat control response. In order to solve this problem, we designed a predictive controller based on PI control to progress superheat control performance. The control performance was investigated through some experiments to verify the effectiveness of the predictive controller.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.6-12
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• 2007

In this paper, an robust adaptive backstepping controller is proposed for the speed control of separately excited DC motor in pure electric vehicles. A general electric drive train of PEV is conceptually rearrange to major subsystems as electric propulsion, energy source, and auxiliary subsystem and the load torque is modeled by considering the aerodynamic, rolling resistance and grading resistance. Armature and field resistance, damping coefficient and load torque are considered as uncertainties and noise generated at applying load torque to motor is also considered. It shows that the backstepping algorithm can be used to solve the problems of nonlinear system very well and robust controller can be designed without the variation of adaptive law. Simulation results are provided to demonstrate the effectiveness of the proposed controller.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.115-121
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• 1996

Multi-axes driving system is more suitable for FMS(Flexible Manufacturing System) compared with a conventional single-azis driving system. It has some merits such as flexibility in operation, improvement of net working rate, maintenance free because of no gear train, etc. However, studies on position synchronous control for high precision in the multi-axes driving system are not enough. In this paper, a new method of position synchronous control is suggested in order to apply to the multi- axes driving system. The proposed method is structured very simply using speed and position controller based on PID control law. Especially, the position controller is designed to keep position error to minimize by controlling either speed of two motors. The effectiveness of the proposed method is successfully confirmed through several experiments.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.355-358
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• 2009

This paper proposes efficiency optimization control of IPMSM drive using multi hybrid fuzzy controller(HFC). The design of the speed controller based on fuzzy-neural network that is implemented using fuzzy control and neural network. The design of the current based on HFC using model reference and the estimation of the speed based on neural network using ANN controller. In order to maximize the efficiency in such applications, this paper proposes the optimal control method of the armature current. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal control of the armature current. The minimization of loss is possible to realize efficiency optimization control for the proposed IPMSM The optimal current can be decided according to the operating speed and the load conditions. This paper considers the design and implementation of novel technique of high performance speed control for IPMSM using multi HFC. Also, this paper proposes speed control of IPMSM using HFC1, current control of HFC2-HFC3 and estimation of speed using ANN controller. The proposed control algorithm is applied to IPMSM drive system controlled HFC, the operating characteristics controlled by efficiency optimization control are examined in detail.