• Title/Summary/Keyword: Improved PID Controller

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Hybrid Sliding-Mode Controller for the Speed Control of a Hydraulic Inverter-Fed Elevator (유압식 인버터 엘리베이터의 속도제어를 위한 하이브리드 슬라이딩모드제어기)

  • Han, Gueon-Sang;Park, Jae-Sam;Ahn, Hyun-Sik;Kim, Do-Hyun
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.38 no.6
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    • pp.37-47
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    • 2001
  • Due to the friction characteristics of pump, cylinder packing and passenger car, in the elevator actuated with hydraulic inverter-fed systems, there exist dead zones, which cannot be controlled by a PID controller. To overcome the drawbacks, in this paper, we propose a new hybrid control scheme, which switches the modes between a sliding mode controller and a PID controller. The proposed hybrid control scheme achieves an improved control performance by using both controllers. We first propose a design method of sliding mode controller for a hydraulic elevator system controlled by inverters, then fellowed by a design method of a hybrid sliding mode control scheme is proposed. The effectiveness of the proposed control scheme are shown by simulation results, which the proposed hybrid control method yields better control performance then the PID controlled scheme, not only in the zero-crossing speed region but also in the overall control region including steady-state region.

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MPC based path-following control of a quadcopter drone considering flight path and external disturbances in MATLAB/Simulink (MATLAB/Simulink 기반 주행 경로와 외란을 고려한 쿼드콥터 드론의 모델 예측 제어 기반 경로 주행 제어)

  • Soon-Jae Gwon;Gu-Min Jeong
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.16 no.6
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    • pp.472-477
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    • 2023
  • In this paper, we proposes the use of Model Predictive Control (MPC) techniques to enable quadcopter drones to effectively follow paths and maintain flight safety even under dynamic external environments and disturbances. Through simulations conducted in MATLAB/Simulink, the performance of two controllers, PID and MPC, is compared in flight scenarios with disturbances. The proposed design method shows that the MPC controller, when compared to the PID controller, exhibits a difference in the Mean Squared Error between the intended flight path and the actual path of the quadcopter drone. This difference is 0.2 in performance under no disturbance, and it increases to 0.8 under disturbance, demonstrating the improved path following accuracy of the MPC controller.

Longitudinal Tension Control at Start and Stop in a Multi-span Continuous Process System (변속시의 멀티 스팬 연속 공정 시스템의 장력제어)

  • 신기현;권순오
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.584-589
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    • 1994
  • A time-varying nonlinear mathematical model was derived to consider the effect of change in roll radius on tension varation during winding and unwinding. A variable-gain PID controller was designed for tension control at start and stop in a multi-span continuous process system. The controller gains are updated at every control loop as roll radii continuously change. Computer simulation was carried out by using the mathematical model and the controller developed for a typical operating condition including acceleration and deceleration. When the variable-gain PID controller was used, the tension control performance was improved compared with that of existing control method during start-up and stop.

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Smith-Predictor Controller Design Using New Reduction Model (새로운 축소 모델을 이용한 Smith-Predictor 제어기 설계)

  • Choi Jeoung-Nae;Cho Joon-Ho;Hwang Hyung-Soo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.1
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    • pp.9-15
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    • 2003
  • To improve the performance of PID controller of high order systems by model reduction, we proposed two model reduction methods. One, Original model with two point $({\angle}G(jw)=\;-{\pi}/2,\;-{\pi})$ in Nyquist curve used gradient base method and genetic algorithm. The other, Original model without two point$({\angle}G(jw)=\;-{\pi}/2,\;-{\pi})$in Nyquist curve used to add very small dead time. This method has annexed very small dead time on the base model for reduction, and we remove it after getting the reduced model, and , we improved Smith-predictor for a dead-time compensator using genetic algorithms. This method considered four points$({\angle}G(jw)=0,\;-\pi/2,\;-\pi,\;-3\pi/2)$ in the Nyquist curve to reduce steady state error between original and reduced model. It is shown that the proposed methods have more performance than the conventional method.

Fuzzy Controller Design for Water level Control of Power Plant Drum (화력발전소 드럼의 수위제어를 위한 퍼지 제어기의 설계)

  • 이상혁
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.1
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    • pp.25-30
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    • 2003
  • In this paper, we propose a fuzzy controller design method for the water level control of the power plant drum in the form of nominimum phase system The proposed method is based on T. Takagi and H. Sugeno's fuzzy model. And we illustrate the improved characteristics as the simulation results, comparing with the conventional the PID and LQ controller design methods.

Anti-shock Controller Design for Optical Disk Drive Systems with a Nonlinear Controller (광디스크 드라이브 시스템을 위한 비선형 Anti-shock 제어기 설계)

  • Baek Jong-Shik;Chung Chung Choo
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.9
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    • pp.741-749
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    • 2005
  • This paper presents a nonlinear controller design for optical disk drive systems to improve anti-shock performance. The nonlinear anti-shock controller is added parallel to the original linear servo control loop. In the previous work, a dead-zone nonlinear element is used for the nonlinear controller and a PID control method is used for the linear controller. Although this parallel structure of the controller improves anti-shock performance, it has a narrow stability bound. In this paper, the dead-zone with saturation nonlinear element is proposed for the nonlinear controller. Since this nonlinear element improves stability margin, we can use higher slope gain of dead-zone than that of nonlinear controller using dead-zone only. In the linear controller design, it is shown that the lead-lag control has an improved stability margin over PID control. Numerical simulation results and experimental results show that the proposed method can get better performance to the external shock than previously proposed methods.

On-line Monitoring and Control of Substrate Concentrations in Biological Processes by Flow Injection Analysis Systems

  • Rhee, Jong-Il;Adnan Ritzka;Thomas Scheper
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.9 no.3
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    • pp.156-165
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    • 2004
  • Concentrations of substrates, glucose, and ammionia in biological processes have been on-line monitored by using glucose-flow injection (FIA) and ammonia-FIA systems. Based on the on-line monitored data the concentrations of substrates have been controlled by an on-off controller, a PID controller, and a neural network (NN) based controller. A simulation program has been developed to test the control quality of each controller and to estimate the control parameters. The on-off controller often produced high oscillations at the set point due to its low robustness. The control quality of a PID controller could have been improved by a high analysis frequency and by a short residence time of sample in a FIA system. A NN-based controller with 3 layers has been developed, and a 3(input)-2(hidden)-1(output) network structure has been found to be optimal for the NN-based controller. The performance of the three controllers has been tested in a simulated process as well as in a cultivation process of Saccharomyces cerevisiae, and the performance has also been compared to simulation results. The NN-based controller with the 3-2-1 network structure was robust and stable against some disturbances, such as a sudden injection of distilled water into a biological process.

A control algorithm for driving stability improvement of in-wheel motors vehicle (인휠모터 차량의 주행 안정화 제어 알고리즘 연구)

  • Choe, Seung-Hoe;Kim, Jin-Sung;Heo, Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.206-211
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    • 2011
  • In this paper, a control algorithm for the improvement of yaw and velocity stability of electrical vehicle with two or four in-wheel motors is proposed. The vehicle is modeled with independently operative in-wheel motor wheels. Different frictions on the wheels are regarded as disturbances, which causes driving instability. In this situation the proposed algorithm enables stabilizing the yaw motion and velocity of vehicle simultaneously. The proposed PID controller is composed with two techniques, which enhance the disturbance reject and point tracking performances. One is nonlinear gain function and the other one is improved integral controller operating as time based weight function. Simulation is conducted to reveal its efficient performance.

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Optimized Digital Proportional Integral Derivative Controller for Heating and Cooling Injection Molding System

  • Jeong, Byeong-Ho;Kim, Nam-Hoon;Lee, Kang-Yeon
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.1383-1388
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    • 2015
  • Proportional integral derivative (PID) control is one of the conventional control strategies. Industrial PID control has many options, tools, and parameters for dealing with the wide spectrum of difficulties and opportunities in manufacturing plants. It has a simple control structure that is easy to understand and relatively easy to tune. Injection mold is warming up to the idea of cycling the tool surface temperature during the molding cycle rather than keeping it constant. This “heating and cooling” process has rapidly gained popularity abroad. However, it has discovered that raising the mold wall temperature above the resin’s glass-transition or crystalline melting temperature during the filling stage is followed by rapid cooling and improved product performance in applications from automotive to packaging to optics. In previous studies, optimization methods were mainly selected on the basis of the subjective experience. Appropriate techniques are necessary to optimize the cooling channels for the injection mold. In this study, a digital signal processor (DSP)-based PID control system is applied to injection molding machines. The main aim of this study is to optimize the control of the proposed structure, including a digital PID control method with a DSP chip in the injection molding machine.

Controller Auto-tuning Scheme using System Monitoring inFrequency Domain (주파수역에서 시스템 감시를 이용한 제어기 Auto-tuning기법)

  • 정유철;이건복
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.136-139
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    • 2000
  • Controller refinement scheme to improve the performance of a conventional system automatically in frequency domain is proposed. The controller automatic tuning method features using experimental frequency responses of the conventional closed-loop system, the conventional controller, and the improved closed-Imp system; instead of poorly modeled plant due to non-linearities and disturbances. The improved closed-loop system characteristics is automatically acquired by the conventional closed-loop system characteristics and the proposed performance index in system bandwidth. And the proper controller is realized by least squares approximation in frequency domain. To testify the usefulness of the approach, experimental results of robot path-tracking control applied with various controllers is used, and then is analyzed with respect to a equivalent proportional controller. Experimental results and analytic results are well-matched.

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