International Journal of Applied Electromagnetics and Mechanics - Volume 24, issue 3-4

Authors: Oh, Tae-Seok | Lee, Wang-Heon | Kim, Il-Hwan

Article Type: Research Article

Abstract: This paper presents a gain tuning method to obtain optimal gains in designing a 2-DOF-PID controller. A 2 degree-of-freedom PID controller has been designed to compensate the effects of disturbance without degrading tracking performance. But it is not easy to get optimal gains and keep system stability during the tuning process with real-time tuning methods. Thus we suggest an offline tuning method by genetic algorithm. For the experimental system we consider a commercial sewing machine that …requires high speed, robustness and accuracy. Modeling techniques based on neural networks have proven to be quite useful for building good quality models from measured data. So it is modeled by a neural network that is configured as an output-error dynamical system. Then using the model, we search optimal gains for 2-DOF-PID controller with genetic algorithm in offline simulation. Experimental results confirm that the model is a good approximation of sewing machine dynamics and that the proposed control methodology is effective. Show more

DOI: 10.3233/JAE-2006-798

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 131-145, 2006

Authors: Karimian, M. | Towhidkhah, F. | Rostami, M.

Article Type: Research Article

Abstract: By using Model Predictive Impedance Control (MPIC), two essential questions about human walking control have been considered in this paper: Which parameters are controlled by the control system and what strategies are applied? As a general method, MPIC was proposed as a possible model for controlling human movements in the previous paper of one of the authors [1] and it was also applied to periodic movements such as walking [2]. According to the acceptable results of …primary experiences, a more realistic walking model is presented in this paper to be controlled by MPIC strategy. A 3-dimensional 5-link simulated walking robot with 8 degrees of freedom in sagittal and lateral planes is employed to be analyzed while being controlled on an irregular condition, like ascending and descending stairs. The objective of the controller is to optimize the energy consumption, vertical orientation of the body, and forward speed of its center of mass. Visual feedback effect is applied when the robot targets specific footprints over the walking terrain. Each optimization sequence has been applied during the prediction horizon with one human step duration. The results have been animated for comparison with natural walking of a human in similar conditions. Show more

Keywords: Model predictive impedance control, biped walking model, rough terrains

DOI: 10.3233/JAE-2006-799

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 147-162, 2006

Authors: Uchida, Masaki | Yabumi, Takao | Morita, Yoshifumi | Fuwa, Katsuhiko | Kando, Hisashi

Article Type: Research Article

Abstract: An EMV (ElectroMagnetic engine Valve) has received a great deal of attention due to the growing importance of issues such as fuel economy and environmental protection in the automotive. This paper describes the development of a moving-magnet-type linear motor for the EMV. The mechanical structure is designed through magnetic field analysis. Then, in order to verify the control performances of the trial system, some experiments are performed by using the PD feedback and feed forward control. …As a result, the developed linear motor enables high-speed positioning with an amount of lift of 7.6[mm] and a positioning accuracy of 50[μm] in a time of 0.004[s], which shows that the requirements are satisfied. Moreover, the developed linear motor enables the following control (sinusoidal wave reference: a driving frequency of 100[Hz] and an amount of lift of 7.6[mm]) which corresponds to a number of engine revolutions of 5000[rpm]. Show more

DOI: 10.3233/JAE-2006-800

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 163-176, 2006

Authors: Min, Sanghyun | Um, Taijoon | Joo, Youngcheol | Kong, Yonghae | Chun, Ingook | Kim, Seungwoo | Bang, Jaecheol

Article Type: Research Article

Abstract: Solid freeform fabrication system has recently been used in many practical areas for fast manufacturing of a concept model. Prototype model can easily be made using a solid freeform fabrication system at the product developing step for checking and correcting the probable design error. The system considered for this paper basically consists of laser cutting apparatus and material handling equipment. The basic principle of the process is such that 3D CAD data is sliced into thin …2D layers, each slice is cut by laser source along the profile of the 2D layer information and the slices are stacked for sintering in a furnace. Material for the process initially was raw ceramic green tape and becomes hard enough for practical use after sintering. Show more

Keywords: Solid freeform fabrication system, laser cutting, transferring, accumulating, optimization

DOI: 10.3233/JAE-2006-801

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 177-185, 2006

Authors: Jarng, Soon Suck

Article Type: Research Article

Abstract: This paper describes the application of the coupled FE-BEM (finite element-boundary element method) for the numerical harmonic analysis of the linear dynamic behavior of a magnetostrictive Terfenol-D rod in water. The magnetostrictive rod is three-dimensionally modeled to transduce applied electric current in a helical coil around the rod to mechanical displacement. The steady-state resonance response of the displacement is shown.

DOI: 10.3233/JAE-2006-802

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 187-193, 2006

Authors: Kim, Lee-Hun | Yu, Jae-Sung | Lee, Won-Cheol | Won, Chung-Yuen | Hahm, Nyon-Kun | Kim, Gyu-Sik

Article Type: Research Article

Abstract: Much attention has been given to EMI problems generated in variable speed AC drive systems. Zero switching states of PWM inverter generate large common mode voltage. This paper focuses on the voltage modulation in order to mitigate common mode voltage. It shows that the common mode voltage can be reduced much more by choosing the PWM switching method in which each carrier wave is 120 degrees out of phase. To demonstrate the practical significance of our …results, we presented some simulation and experimental results. Show more

Keywords: EMI, common mode voltage, voltage modulation method, carrier wave

DOI: 10.3233/JAE-2006-803

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 195-207, 2006

Authors: Lim, Ho Soon | Chong, Kil To | Su, Hua

Article Type: Research Article

Abstract: Induction motors play an important role in the safe and efficient operation of industrial plants because they are considered inherently reliable due to their robust and relatively simple design. Therefore, there is an indispensable need to monitor their health and performance. And the detection and diagnosis of motor faults is the base to improve the efficiency of industrial plants. In this paper, a residual model-based fault detection method is proposed for steady state vibration signals of …induction motors. The stationary signal had been extracted from the entire signal using data segmentation. The reference model in spectra is obtained statistically to represent the healthy condition. The ratio of RMS of residuals is used as a fault indicator for detecting motor faults. The effectiveness of the proposed approach in detecting a wide range of mechanical faults is demonstrated through the experiments applied on an 800 hp motor, and it is shown that a robust and reliable induction motor fault detection system has been produced. Show more

Keywords: Fault detection, induction motors, vibration signal

DOI: 10.3233/JAE-2006-804

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 209-223, 2006

Authors: Jiang, Zhongwei | Morita, Minoru | Watanabe, Tetsuyou | Kato, Shoichi | Suzuki, Michiyasu

Article Type: Research Article

Abstract: A cerebral thrombus or blood clot might cause cerebral stroke and even decease if the clot could not be dissolved within several hours after it was formed. In order to carry out an efficient clinical treatment, there exist several problems required to resolve. One of them is the measurement of solubility of blood clots in vivo, which is very important for the doctor to know the situation of the clot dissolution in an operation. In this paper, a …fundamental study, on how to assist the dissolution of the thrombus with a few amount of thrombolytic agent and to measure the solubility of the thrombus in-vivo during the operation, is presented. A mechanical micro stirrer for dissolution of the thrombus is developed as a slight beam embedded with a piezo-cell. Furthermore, an approach using the stirrer also as a sensor to evaluate the solubility of blood clots in the operation is proposed. This idea comes from that the solution state of the blood influences the mechanical impedance of the stirrer, which can be measured with a high accuracy by checking the electric impedance of the piezo-cell with the so-called piezoelectric impedance based measuring technique. Both the performance of the dissolution and the measurement of the solubility by the same stirrer are investigated in detail and their validations are verified experimentally. Show more

Keywords: Micro-stirrer, piezo-cell, cerebral thrombus, dissolution, solubility, measurement, in-vivo

DOI: 10.3233/JAE-2006-805

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 225-234, 2006

Authors: HO, Choi Kyoung | Sasaki, Minoru

Article Type: Research Article

Abstract: Every movement, perception and thought we perform is associated with distinct neural activation patterns. Neurons in the brain communicate with each other by sending electrical impulses that produce currents. These currents give rise to electrical fields that can be measured outside the head. It shows some variation on the electroencephalographic signals. In recent devices, the EEG signals measured from head surface are a sum of all the momentary brain activation. With these EEG signals, it is …difficult to distinguish the patterns correlated with a certain event from the signals. However, the system must discriminate some patterns with some events especially for any kind of device as a brain control interface system. In this experiment, the sensory-motor cortex of humans has been extensively studied. Activation related to several movements on both sides of the sensory-motor cortices in imaginary. The activation patterns during imagination of several movements resemble the activation patterns during preparation of movements. The result represents the system based on the optimal filters discriminated at least 60% of mental imageries. Show more

DOI: 10.3233/JAE-2006-806

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 235-246, 2006

Authors: Yamada, Hiroyuki | Sasaki, Minoru | Nam, Yoonsu

Article Type: Research Article

Abstract: This paper describes vibration control and position control of a micro-actuator for hard disk drives using self-sensing actuator. A stabilizing feedback control low is designed by using Lyapunov's direct method. The feedback control law depends only on the time derivative of tip slope in the micro-actuator. The self-sensing actuation using the electrical RC bridge circuit can measure strain rate in the micro-actuator. This sensing signals correspond to the time rate of tip slope in the micro-actuator. …The feedback controller derived from Lyapunov's direct method can realize by using the self-sensing signal. A two-degree-of-freedom control system consists of a feedforward and the feedback controller. The feedforward controller is designed by using inverse dynamic system, while the stabilized feedback controller is designed by Lyapunov's direct method. Numerical simulation and experimental results confirm the feasibility of the proposed control system. Show more

Keywords: Micro-actuator, self-sensing actuator, two-degree-of-freedom control, Lyapunov's direct method

DOI: 10.3233/JAE-2006-807

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 24, no. 3-4, pp. 247-259, 2006