• Proceedings of the KIEE Conference
• /
• 2008.04c
• /
• pp.128-130
• /
• 2008

This paper presents an algorithm to design a self-tuning proportional-integral(PI) speed controller for servo systems. The control gains are calculated with estimated system parameters, i.e. inertia and viscous damping which are estimated by initial operation. The simulation and experimental results show the feasibility and performance of the proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.680-683
• /
• 1996

The dynamics of the vehicle system has highly nonlinear components such as an engine, a torque converter and variable road condition. This thesis proposes a Fuzzy Logic Algorithm that shows better control performance than Antiwindup PI in the highly nonlinear vehicle system. Traction Control System(TCS), which adjusts throttle valve opening by Fuzzy Logic Algorithm improves vehicle drivability, steerability and stability when vehicle is starting and cornering. When a throttle valve is opened at large degree, Fuzzy Logic Algorithm shows better performances like a small settling time and a small oscillation than Antiwindup PI in simulation. The decreased desired slip ratio improves steerability in the simulation when a vehicle is cornering. The Fuzzy Logic Algorithm has been tested by a 1/5-scale vehicle for tracking the constant desired velocity.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.1
• /
• pp.13-20
• /
• 2005

This paper has proposed an algorithm for the initial pole position estimation of a permanent magnet linear synchronous motor(PMLSM). The algorithm finds the initial pole position observing the maximum values of a position generated by the new proposed two reference frames for the same force input. So, the proposed algorithm does not utilize the motor parameters and is insensitive to them. Moreover, the proposed algorithm is easily realized because the proposed method is just using PI controller

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.2
• /
• pp.209-216
• /
• 1996

This paper deals with the speed control of the switched reluctnace motor using fuzzy PI controller. A fuzzy logic control provides a good approach to nonlinear system because it does not require a detailed mathematical model to formulate the algorithm. The fuzzy PI controller is implemented by MCS80C196KB, a 16 bit one-chip microcontroller, and an EPROM is used for the commutation logic of the SRM. The simulation and experimental results show that the performance of the fuzzy PI controller is superior to that of the conventional PI controller in terms of response time, settling time and overshoot. In particular, the robustness of the system is largely improved.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.2
• /
• pp.483-494
• /
• 1996

In this paper, we proposed the receive decoder and Virterbi algorithm with sliding multiple symbol detection using MLSE. the informationis transmitted by the phase difference of the adjacent channel signal at the .pi./4 shift QPSK. In order to apply the .pi./4 shift QPSK to TCM, we use the signal set expansion and the signal set partition by the phase differences. And the Viterbi decoder containing branch mertrice of the squared Euclidean distance of the first, second and Lth order phase difference is introduced in order to extract the information in the differential detection of the Trellis-Coded .pi./4 shift QPSK. The proposed Viterbi decoder and receiver are conceptually same to the sliding multiple symbol detection method using the MLSE. By uisng this method, the study shows that the Trellis-Coded .pi./4 shift QPSK is an attractive scheme for the power and the bandimited systems while also improving the BER performance when the Viterbi decoder is employed to the Lth order phase difference metrics.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.2
• /
• pp.233-243
• /
• 1994

Generally, fuzzy PI controller that regulates the gains using fuzzy algorithm shows high performance in speed response. However, it has some problems to the load inertia variation, because the change of speed error(CE) is in a fixed range. As load inertia increases, CE is decreased and the usuage of fuzzy table is limited. Therefore, the output of the fuzzy controller has a limited range. This paper proposes an improved fuzzy PI controller. To reduce the speed overshoot, we adapt a control method that selects a proper CE range with respect to the load inertia variation. The proposed controller is applied to the vector controlled system with 2.2kW induction motor. Some simulation and experimental results are exhibited. With these results, we can easily find that proposed PI controller is more robust than the conventional fuzzy PI controller against the load inertia variation.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.77.1-77
• /
• 2001

In this paper, we propose a control scheme for improving the performance of a conventional Proportional-Integral (PI) controller for Active Queue Management (AQM) supporting TCP flows. When the PI controller is used for AQM, the windup phenomenon of the integral action causes the performance degradation. Therefore we model AQM as a system with a saturator and apply anti-windup methods to the PI controller for AQM. We compare the performances of anti-windup algorithm with the conventional PI controller through ns simulations. The simulation results show that the PI controller with anti-windup method performs better than the conventional PI controller.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.1
• /
• pp.99-108
• /
• 1999

In this paper, we propose $\pi$/4 QPSK scheme with block modulation algorithm, which can reduce preamble in order to transmit ATM cell efficiently in the uplink channel of LMDS, and also designed a new carrier recovery circuit which can improve carrier synchronization performance of block demodulation algorithm. The $\pi$/4 QPSK scheme employing the proposed block modulation algorithm achieved efficient frame transmission by making use of a few preamble when carrier synchronization, symbol timing synchronization and slot timing synchronization were performed by burst data of ATM cell in LMDS environment. For performance evaluation of the proposed method, a simulation analyzing the variation of carrier synchronization, symbol timing synchronization and slot timing synchronization using LMDS environment and burst mode condition was executed. In the simulation, the proposed method showed a good performance even though the reduced preamble as a few aspossible when carrier synchronization, symbol timing synchronization and slot timing synchronization is performed.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.2
• /
• pp.9-14
• /
• 2022

In this study, we propose a method for moving a device such as a flexible air sculpture while stably maintaining the user's desired posture. To accomplish this, a robot system with a structure of a mobile robot capable of running according to a given trajectory was studied by applying the PI algorithm and horizontal maintenance posture control using IMU. The air sculptures used in this study often use thin strings in a fixed posture. Another method is to put a load on the center of gravity to maintain the posture, and it is a system with flexibility because it uses air pressure. It is expected that these structures can achieve various results by combining flexible structures and mobile robots through the convergence process of digital sensor technology. In this study, posture control was performed by fusion of the driving technology of AGV(Automatic Guided Vehicle),, a field of robot, and technologies applying various sensors. For verification, the given performance evaluation was performed through an accredited certification test, and its validity was verified through an experiment.

• Korean Journal of Optics and Photonics
• /
• v.16 no.6
• /
• pp.516-520
• /
• 2005

We proposed an efficient phase stepping method for the use in fiber-optic ESPI. To improve phase-stepping accuracy and efficiency, a fiber-optic Michelson interferometer was phase-modulated by a ramp-driven fiber stretcher, resulting in 4$\pi$ phase excursion in the PD interference signal. The zero-crossing points of the signal, which have consecutive $\pi$ phase difference, were carefully detected and used to generate trigger signals for the CCD camera. From the experimental results by using this algorithm, $\pi$/2 phase-stepping errors between the speckle patterns were measured to be less than 0.6 mrad with 100 Hz image capture speed. Also it has been shown that the error from the nonlinear phase modulation and environmental perturbations could be minimized without any feedback algorithm.