• International Journal of Ocean System Engineering
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• v.1 no.4
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• pp.192-197
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• 2011

This paper describes the mathematical modeling, control algorithm, system design, hardware implementation and experimental test of a Manta-type Unmanned Underwater Vehicle (MUUV). The vehicle has one thruster for longitudinal propulsion, one rudder for heading angle control and two elevators for depth control. It is equipped with a pressure sensor for measuring water depth and Doppler Velocity Log for measuring position and angle. The vehicle is controlled by an on-board PC, which runs with the Windows XP operating system. The dynamic model of 6DOF is derived including the hydrodynamic forces and moments acting on the vehicle, while the hydrodynamic coefficients related to the forces and moments are obtained from experiments or estimated numerically. We also utilized the values obtained from PMM (Planar Motion Mechanism) tests found in the previous publications for numerical simulations. Various controllers such as PID, Sliding mode, Fuzzy and $H{\infty}$ are designed for depth and heading angle control in order to compare the performance of each controller based on simulation. In addition, experimental tests are carried out in a towing tank for depth keeping and heading angle tracking.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.15-20
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• 2002

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the automatic assembly tasks using hydraulic manipulators. In this manuscript, we applied a compliance control, which is based on the position control by a disturbance observer for our manipulator system. A reference trajectory modification method is proposed in order to achieve accurate force control even though the stiffness and the position of the environment change. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved under various environment conditions. The proposed force control algorithm is applied to the approaching of bolt and the wrenching of nut tasks as one typical task in the maintenance work of live power electric line and is experimentally confirmed very effective for the task.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.1
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• pp.35-41
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• 2012

This paper proposes a moving object detection algorithm for active camera system that can be applied to mobile robot and intelligent surveillance system. Most of moving object detection algorithms based on a stationary camera system. These algorithms used fixed surveillance system that does not consider the motion of the background or robot tracking system that track pre-learned object. Unlike the stationary camera system, the active camera system has a problem that is difficult to extract the moving object due to the error occurred by the movement of camera. In order to overcome this problem, the motion of the camera was compensated by using SURF and Pseudo Perspective model, and then the moving object is extracted efficiently using stochastic Label Cluster transport model. This method is possible to detect moving object because that minimizes effect of the background movement. Our approach proves robust and effective in terms of moving object detection in active camera system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.984-985
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• 2008

In this paper, MPPT(maximum power point tracking) control method of the seaflow generation system using DC-DC converters is proposed. This system consists of a variable speed seaflow generation system with permanent magnet synchronous generator, diode rectifier and DC-DC converter. In this proposed seaflow generation system, diode rectifier and DC-DC converter use for converting AC to DC and maximum power generation control, respectively. Advantages of MPPT control method presented in this paper don’t need to use the characteristic of the seaflow turbine at various seaflow speed and measure the seaflow speed and the rotating speed of seaflow turbine. Therefore, the proposed system has the characteristics of lower cost, lower complexity and higher efficiency. The effectiveness of algorithm is simulated and confirmed through Matlab Simulink.

• Journal of Broadcast Engineering
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• v.25 no.4
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• pp.576-586
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• 2020

Analyzing baseball games using sensors such as radars or riders is expensive. In this paper, we propose an algorithm to detect pitch shots and hit shots using baseball video and to generate ball trajectories within hit shots using camera movement. After the pitch shot and the hit shot detection using object detection and optical flow, we generate the transformation relationship between frames and ball locations in the frame, and calculates the ball trajectory. The performance of the proposed method is evaluated for three KBO baseball video sequences, and the detection accuracy and detection rate of pitch shot and hit shot were within 89-95 [%], and the average error for shot range was 13.6[m], The direction error was 7.5° and foul classification accuracy was 98.6%.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.20-28
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• 2010

In this paper, we propose a hand gesture interface for the manipulation of augmented objects in 3D space using a camera. Generally a marker is used for the detection of 3D movement in 2D images. However marker based system has obvious defects since markers are always to be included in the image or we need additional equipments for controling objects, which results in reduced immersion. To overcome this problem, we replace marker by planar hand shape by estimating the hand pose. Kalman filter is for robust tracking of the hand shape. The experimental result indicates the feasibility of the proposed algorithm for hand based AR interfaces.

• Journal of Auto-vehicle Safety Association
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• v.9 no.3
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• pp.19-23
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• 2017

This paper presents a lateral driver model with neuromuscular system to evaluate the performance of electric power steering (EPS). Output of most previously developed driver models is steering angle. However, in order to evaluate EPS system, driver model which results in steering torque output is needed. The proposed lateral driver model mainly consists of 2 parts: desired steering angle calculation and conversion of steering angle into steering torque. Desired steering angle calculation part results in steering angle to track desired yaw rate for path tracking. Conversion of steering angle into torque is consideration with neuromuscular system. The proposed driver model is investigated via actual driving data. Compared to other algorithms, the proposed algorithm shows similar pattern of steering angle with human driver. The proposed driver can be utilized to efficiently evaluate EPS system in simulation level.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.803-806
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• 2003

This paper presents a detailed study of the extended Kalman filter for estimating the rotor speed of an IM drive. The general structure of the Kalman filter is reviewed and the various system vectors and matrices are defined. By including the rotor speed as a state variable, the EKF equations are established from a discrete two axis model of the three-phase induction motor using the software MATLAB/Simulink, simulation of the EKF speed estimation algorithm is carried out for an induction motor drive with direct self control. The investigations show that the EKF is capable of tracking the actual rotor speed provided that the elements of the covariance matrices are properly selected.

• Journal of Power Electronics
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• v.12 no.2
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• pp.344-356
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• 2012

In recent years, multilevel technology has become an effective and practical solution in the field of moderate and high voltage applications. This paper discusses an APF with a three-level NPC inverter. Obviously, the application of such converter to APFs is hindered by the problem of the voltage unbalance of DC capacitors, which leads to system instability. This paper comprehensively analyzes the theoretical limitations of the neutral-point voltage balancing problem for tracking different harmonic currents utilizing current switching functions from the space vector PWM (SVPWM) point of view. The fluctuation of the neutral point caused by the load currents of certain order harmonic frequency is reported and quantified. Furthermore, this paper presents a close-loop digital control algorithm of the DC voltage for this APF. A PI controller regulates the DC voltage in the outer-loop controller. In the current-loop controller, this paper proposes a simple neutral-point voltage control method. The neutral-point voltage imbalance is restrained by selecting small vectors that will move the neutral-point voltage in the direction opposite the direction of the unbalance. The experiment results illustrate that the performance of the proposed approach is satisfactory.

• Journal of Power Electronics
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• v.17 no.5
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• pp.1150-1159
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• 2017

Flexibility in the power control of ultrasonic transducers has remained a challenge for cleaning applications. This paper introduces a modification of the existing piezoelectric ceramic transducer (PCT) circuit to increase the range of operation through its impedance characteristics. The output power is controlled using the asymmetrical voltage-cancellation (AVC) method. Together with a phase-locked loop control, the switching frequency of the inverter is automatically adjusted to maintain a lagging phase angle under load-parameter variations during the cleaning process. With the proposed modification, the region of the zero-voltage switching (ZVS) operation is extended, which results in a wider range of output power control. A hardware prototype is constructed and the control algorithm is implemented using an STM32F4 microcontroller. Simulation and experimental results are provided to verify the proposed method for a 50-W PCT. The operating frequency and output power ranges under study are 37 - 41 kHz and 15.8 - 50 W, respectively.