Pathumwan Institute of Technology

About: Pathumwan Institute of Technology is a based out in . It is known for research contribution in the topics: Control theory & Control system. The organization has 153 authors who have published 228 publications receiving 980 citations.

Discontinuous SVPWM Techniques of Three-Leg VSI-Fed Balanced Two-Phase Loads for Reduced Switching Losses and Current Ripple

Abstract: In this paper, various types of discontinuous space vector pulse-width modulation techniques for a three-leg voltage source inverter supplying balanced two-phase loads are proposed. The main objectives of the paper are to analyze switching loss characteristics associated with semiconductor devices and to reduce output current ripple by dealing with various types of zero space vector time in each switching sequence. Capabilities of reductions in switching losses and current ripple for both balanced and unbalanced output phase voltages at high modulation index and load power factor angle of 30° lagging are focused. The validity of the proposed techniques is verified by simulation and experimental results in terms of voltage spectrum, current waveforms, reductions in switching losses, and output current ripple at high modulation index when compared to a continuous space vector pulse-width modulation technique.

Identification and hybrid impedance control of human skin muscle by multi-fingered robot hand

Abstract: This paper proposes an intelligent massage control system by using multi-fingered robot hand with hybrid impedance control, which is able to create the movement and the force of robot such as the human's massage. Therefore, the various massage points, such as the change of the stiffness of human skin muscle, can be controlled by using impedance control method. The hybrid impedance control is comprised of the two methods of the position-based and the force-based impedance control were applied. The position-based impedance control is used to control the lateral position of massage on the human skin muscle. On the other hand, the force-based impedance control is used to control the force of the vertical direction on human skin muscle. This paper also gives the identification of human skin muscle through robot perception of impedance to decide the parameter of impedance controller. The control strategy using impedance control to implement an adaptive control system is presented, when human condition is changed with soft and hard skin muscle. Effectiveness of massage control system by using multi- fingered robot hand with hybrid impedance control is demonstrator through actual massage experiments of pushing and rubbing motion.

A fuzzy logic modelling of dynamic scheduling in FMS

Abstract: This paper is concerned with scheduling in flexible manufacturing systems (FMSs) using a fuzzy logic (FL) approach. Four fuzzy input variables: machine allocated processing time, machine priority, due date priority and setup time priority are defined. The job priority is the output fuzzy variable, showing the priority status of a job to be selected for next operation on a machine. The model will first select the machines and then assign operations based on a multi-criteria scheduling scheme. The performance of the approach is compared against established methods reported in the literature. The performance measures considered average machine utilisation, meeting due dates, setup times, work in process and mean flow times. The test results demonstrate the superiority of the fuzzy logic approach in most performance measures.