Heung-Ho Lee

Trotting gait analysis of a lizard using motion capture

Research into the gait planning of a walking robot is the underlying development of quadruped robots. Despite the efforts in stable gait planning, many walking robots that have been developed thus far do not have enough ability to adapt to uneven territory. In this paper, we acquired the motion data of the trotting lizards using the motion capture equipment and analyzed the gait systematically. In addition, we applied it to the kinematic model of the lizard and acquired the trajectory of each joint through an inverse kinematic solution. Moreover, we proposed the joint space-based gait of the lizard model by approximating the acquired joint trajectory to a sinusoidal function. We verified through the simulation that the proposed gait faithfully follows actual gait of lizards.

A study on reliability based assessment algorithm for high voltage induction stator windmgs

Currently high voltage induction motors are widely used and play a significant role in many fields including water power plants. Though reliable, the power equipment has been known to have several maintenance problems. These equipment problems often result in an excessive maintenance cost per fiscal year, which has been derived either from a traditional time-based maintenance schedule or a non-scientific asset management of equipment repair/replacement. In order to reduce the financial burden of equipment replacement, it is imperative to develop a sound evaluation method of the reliability of the power motors either by accurately predicting the rate of fault occurrence or by standardizing the diagnosis of the high voltage induction motors. The purpose of this paper was to develop a standard evaluation algorithm for the condition of the stator windings of high voltage induction motors. Several technical tests were utilized in this study including the measurements of AC current (ΔI), dissipation factor (tanô), partial discharge (PD) magnitude, and polarization index (P.I.). The AC current test produced additional information on the insulation strength of the stator winding of water supply pump motor in operation. The suggested algorithm based on the Risk-Based Maintenance method could make a significant contribution to the reliability assessment.

A study for parallel operation of a synchronous generator

This studys purpose is the development of diesel generator and controller for stable power operation with design in integrated shift type hybrid generator system excitation diesel and wind power generator in single AC system.

The Development of Boiler Furnace Pressure Control Algorithm and Distributed Control System for Coal-Fired Power Plant

This paper is written for the development and application of boiler furnace pressure control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. The control algorithms were designed in the shape of cascade control for two parts of furnace pressure control and induced draft fan pitch blade by standard function blocks. This control algorithms were coded to the control programs of distributed control systems. The simulator for coal-fired power plant was used in the test step and automatic control, sequence control and emergency stop tests were performed successfully like the tests of the actual power plant. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.

The Development of Boiler Combustion Air Control Algorithm for Coal-Fired Power Plant

This paper is written for the development of boiler combustion air control algorithm of coal-fired power plant by the steps of design, coding and test. The control algorithms were designed in the shape of cascade control for two parts of air master, forced draft fan pitch blade by standard function blocks. This control algorithms were coded to the control programs of distributed control systems under development. The simulator for coal-fired power plant was used in the test step and automatic control, sequence control and emergency stop tests were performed successfully like the tests of the actual power plant. The reliability will be obtained enough to apply to actual site if the total test has been completed in the state that all algorithms were linked mutually. It is expected that the project result will contribute to the safe operation of domestic power plant and the self-reliance of coal-fired power plant control technique.

A Study on Parameter Estimation of the Synchronous Generator System based on the Modified PSO

This paper includes a method for estimating the parameter of a synchronous generator and exciter using the modified particle swarm optimization. A solid round rotor synchronous generator and exciter have been modeled with the saturation function. They are regarded as state of being cooperative to a infinite bus. The behavior characteristic of all particles assigned to a parameter needs to be reflected in the PSO algorithm to fine out more close result to the optimal solution. The results of the simulation to estimate the parameters of the synchronous generator and exciter in the modified PSO algorithm are described

Parameter estimation of the synchronous generator exciter based on PSO

This paper includes method of parameter estimation on a synchronous generator exciter using the particle swarm optimization. A solid round rotor synchronous generator and exciter have been modeled as the linear state variable with additional saturation function. The results of the simulation which the parameters of the exciter could be obtained by an objective function with integral squared error are described.

The study of output increasing of the straight type turbine generator

The optical control method to obtain the maximum output with two hydraulic turbine generators directly connected of a pipe at the same flow rate is required. The output changes depend on how many open positions of upstream and downstream turbine runner is at the same flow rate. As a result, we can obtain the maximum power at the different open positions of upstream and downstream turbine with less than constant flow, and we can also get the maximum output at the same open positions of them with more than constant flow.

A Study on Deterioration Evaluation Method by Condition Monitoring and Diagnosis for Aging Oil-immersed Power Transformers

Nowadays new water supply projects have been on the decline as the water-power constructions have saturated, which means that the existing power equipment have slowly aged and they require more efforts to maintain the system performance. An effective asset management method of power equipment has become a great necessity from both economical and technical aspects. To be balanced, the asset management should look into all three parts: management, engineering, and information. The purpose of this paper is to study a Risk-Based Maintenance (RBM) matrix method through the deterioration evaluation algorithm for an efficient reliability assessment of oil-immersed power transformers by considering both asset management and technical evaluation. Make use of this result, the equipment will be decided to be replace or repair otherwise on service.

Obtaining contact parameters for MBDS of a wheelless snake robot

This paper shows a way to obtain contact parameters for multi-body dynamics simulation (MBDS) of a wheelless snake robot, KAEROT-snake V. We developed a simulation model of the snake robot in a commercial MBDS software RecurDyn(V8). RecurDyn provides a convenient way to model contact geometries directly from CAD models, which are very close to the actual shape. Contact parameters such as spring, damping and friction coefficient are very important in MBDS so that we obtained the contact parameters through experiments of falling and sliding test. The contact parameters were obtained by analyzing the images of the test and the MBDS simulation of the test. Some locomotion simulation results for the snake robot were experimentally verified.