• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.7
• /
• pp.1234-1243
• /
• 1992

A systematic procedure to design fuzzy PID controllers is developed in this paper. The concept of local fuzzy control cell is proposed by introducing both an adequate global control rule and membership functions to simplify a fuzzy logic controller. Fuzzy decision is made by using algebraic product and parallel firing arithematic mean, and a defuzzification strategy is adopted for improving the computational efficiency based on nonfuzzy micro-processor. A direct method, transforming the typical output of quasi-linear fuzzy operator to the digital compensator of PID form, is also proposed. Finally, the proposed algorithm is applied to an DC-servo motor. It is found that this algorithm is systematic and robust through computer simulations and implementation of controller using Intel 8097 micro-processor.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.5
• /
• pp.199-208
• /
• 2017

Lithium polymer batteries are used in energy storage systems (ESS), electric vehicles (EVs), etc. due to their high safety, fast charging and long lifecycle, and now they are used in agricultural drones. However, when overcharging and overdischarging, the lithium-polymer battery is destroyed in the gap structure in the lithium-ion battery and the battery life is reduced. In order to prevent overcharge and overdischarge, uneven cell voltage Cell balancing system is needed. In this paper, a fuzzy controller suitable for nonlinear systems is proposed by detecting the unbalanced cells by detecting the voltage difference between charging and discharging of each cell, and suggesting the applied cell balancing algorithm. In this paper, we have designed the cell balancing of the battery pack of agricultural drones by fuzzy control and it is designed for equal control between cells. As a final result, we checked whether cell balancing is good, and when there are two cells, Cell balancing was confirmed. We tested whether it could be used for other products. As a result, we confirmed that cell balancing is good regardless of the number of cells used.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.5
• /
• pp.931-940
• /
• 2001

In this paper, I propose Fuzzy Policing Mechanism(FPM) over ATM networks for the control of traffic which is unpredictable and bursty source. The FPM is consist of counter, subtracter and Fuzzy Logic Controller(FLC). The FLC is divided to fuzzifier, inference engine and defuzzifer The output of FLC inputs to the subtractor and it controls the counter. The counter works as a switch in transmission of cells. In simulation, I compared the FPM with the Leaky Bucket algorithm(LBM) in cell loss probability and performance characteristics. As a result, FPM gives lower cell loss probability than that of LBM and has good response behavior The FPM efficiently controls the transmission of packets which are variable traffic source and, it also has good selectivity.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.7C
• /
• pp.664-669
• /
• 2002

In this paper, we propose the fuzzy control algorithm for effective buffer control to connected traffic in ATM networks. The proposed Fuzzy control algorithm has two priorities and uses Fuzzy sets to search for dynamic thresholds. In this words, the difuzzification value controls the threshold in the buffer to according to traffic priority (low or high) using fuzzy set theory for traffic connected after reasoning. Performance analysis result: it was confirmed that with the proposed scheme, performance improves at cell loss rate, when compared with the existing PBS scheme.

• Journal of the Korea Computer Industry Society
• /
• v.3 no.1
• /
• pp.95-104
• /
• 2002

This paper presents some studies on the Internet TCP/IP(Transmission Control Protocol-Internet Protocol) traffic over ATM(Asynchronous Transfer Mode) UBR(Unspecified Bit Rate) and ABR(Available Bit Rate) classes of service. Fuzzy logic prediction has been used to improve the efficiency and fairness of traffic throughput. For TCP/IP over UBR, a novel fuzzy logic based cell dropping scheme is presented. This is referred to as fuzzy logic selective cell drop (FSCD). A key feature of the scheme is its ability to accept or drop a new incoming packet dynamically based on the predicted future buffer condition in the switch. This is achieved by using fuzzy logic prediction for the production of a drop factor. Packet dropping decision is then based on this drop factor and a predefined threshold value. Simulation results show that the proposed scheme significantly improves TCP/IP efficiency and fairness. To study TCP/IP over ABR, we applied the fuzzy logic ABR service buffer management scheme from our previous work to both approximate and exact fair rate computation ER(Explicit cell Rate) switch algorithms. We then compared the performance of the fuzzy logic control with conventional schemes. Simulation results show that on zero TCP packet loss, the fuzzy logic control scheme achieves maximum efficiency and perfect fairness with a smaller buffer size. When mixed with VBR traffic, the fuzzy logic control scheme achieves higher efficiency with lower cell loss.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.39 no.8
• /
• pp.7-13
• /
• 2002

In this paper, we propose an traffic control algorithm for efficient link utilization of ATM-ABR service based on fuzzy logic. The proposed algorithm, controls transmission rates of source according to switch buffer size and input cell tate by using the fuzzy rate . For this method we developed a model and algorithm of fuzzy traffic control method and fuzzy traffic controller which based on ER of VS/VD. For the fuzzy traffic controller, we also designed a membership function, fuzzy control rules, and a max-min inferencing method.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.10B
• /
• pp.854-861
• /
• 2003

In this paper, we proposed the fuzzy control algorithm for efficient buffer control about traffic that is connected in ATM networks. The proposed Fuzzy control algorithm has total traffic arrival ratio, buffer occupancy ratio and Fuzzy set to search for dynamic service rates in server. That is, is based on Fuzzy logic according to the arrival ratio of total traffic and buffer occupancy ratio that is happened and reasoning. Then, made reasoning result control service rates in server about traffic that is connected with defuzzification value. Performance analysis result: it was confirmed that with the proposed scheme, performance improves at cell loss rate, when compared with the existing PBS scheme.

• The KIPS Transactions:PartC
• /
• v.8C no.3
• /
• pp.311-318
• /
• 2001

본 논문에서는 연결수락 제어시 사용자가 전송하는 트래픽 파라메타(샐 개수의 분산값과 평균값)를 압축하여 망에 신고하는 방법을 제안하고, 압축방법에 의한 연결수락제어의 성능을 분석 비교한다. 트래픽 파라메타 압축방법은 K-means, CL(Competitive Learning), Fuzzy ISODATA,FNC(Fuzzy Neural Clustering)를 사용한다. 제안한 트래픽 파라메타의 압축에 의한 연결수락제어는 퍼지 매핑함수(Fuzzy Mapping Funciton)fp 의해 신고한 트래픽 패턴을 추정하고, 전방향 구조의 신경망을 사용하여 연결의 수락/거절을 결정한다. ON-OFF 트래픽 모델 환경에서 컴퓨터 실험을 통하여 여러 가지 압축방법들을 사용한 연결수락제어의 성능을 Fuzziness 값에 따라 비교하였고, 그 결과 FNC 방법이 우수함을 알 수 있었다. EH한 연결수락제어의 성능을 높히기 위해서 관측 프레임의 셀 분산값이 크면 Fuzziness 값을 작게 선정하고, 작으면 상대적으로 크게 선정해야 함을 알 수 있었다.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.9 no.6
• /
• pp.634-643
• /
• 1999

This paper concerns an implementation of f~rry logic controller (FLC') on a reconfigurahle FP

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.3
• /
• pp.305-310
• /
• 1997

In this paper, a fuzzy set based machine-cell formation algorithm for cellular manufacturing is presented. The fuzzy logic is emoloyed to express the degree of appropriateness when alternative machines are specified to process a part shape. For machine grouping, the similarity coefficient based approach is used. The algorithm produces efficient machine cells and part families which maximize the similarity values.