• Title/Summary/Keyword: Real-Time Controller

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Predictive and Preventive Maintenance using Distributed Control on LonWorks/IP Network

  • Song, Ki-Won
    • International Journal of Safety
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    • v.5 no.2
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    • pp.6-11
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    • 2006
  • The time delay in servo control on LonWorks/IP Virtual Device Network (VDN) is highly stochastic in nature. LonWorks/IP VDN induced time delay deteriorates the performance and stability of the real-time distributed control system and hinders an effective preventive and predictive maintenance. Especially in real-time distributed servo applications on the factory floor, timely response is essential for predictive and preventive maintenance. In order to guarantee the stability and performance of the system for effective preventive and predictive maintenance, LonWorks/IP VDN induced time delay needs to be predicted and compensated for. In this paper position control simulation of DC servo motor using Zero Phase Error Tracking Controller (ZPETC) as a feedforward controller, and Internal Model Controllers (IMC) based on Smith predictor with disturbance observer as a feedback controller is performed. The validity of the proposed control scheme is demonstrated by comparing the IMC based on Smith predictor with disturbance observer.

Implementation of Wafer Handling Robot Controller Based on RTAI (RTAI 기반의 웨이퍼처리 로봇 제어기 구현)

  • Chang, Soon-Pill;Shin, Ik-Sang;Moon, Seung-Bin
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.9
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    • pp.45-52
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    • 2008
  • As multiple functions arc required in a robot controller, RTOS(Real Time Operating System) should be adopted to manage complex situations, such as choosing most urgent task among competing ones. In this paper, we implemented RTAI(Real Time Application Interface) based robot controller for wafer handling robots including graphic simulator. We showed how multiple tasks are organized and also explained in detail about task priorities and execution periods. Finally, we presented simulation results.

Design of an Image Processor for UXGA Class LCD

  • Cho, Hwa-Hyun;Choi, Myung-Ryul
    • Journal of Information Display
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    • v.2 no.2
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    • pp.13-21
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    • 2001
  • We propose a universal image processor for a-Si TFT LCD of UXGA class that can display the full screen on the LCD panel with low resolution of video sources such as NTSC, VGA, SVGA, XGA, and SXGA by using the proposed interpolation filter. In addition, we propose a real-time contrast controller for image improvement of multi-gray scale image. The operation of the proposed methods has been verified using Synopsys VHDL and computer simulation. Results show that the proposed methods might be suitable for a UXGA LCD controller for real-time image improvement.

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A Experimental Study of Stochastic Controller Realizing Technique (실험적 연구를 통한 확률제어기 구현)

  • Lee, Jong-Bok;Kim, Yong-Kwan;Yoon, Young-Soo;Choi, Won-Seok;Heo, Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.715-718
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    • 2002
  • A control strategy for a dynamic system under Irregular disturbance by using stochastic controller is developed. In order to design stochastic controller. system dynamic model in real domain is transformed dynamic moment equation in stochastic domain by F-P-K approach. A study of real time control technique for stochastic controller is presented. The performance of stochastic controller is verified through experiment used by real time control technique method.

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Development of Brake Controller for fixed-wing aircraft using hardware In-the-Loop Simulation

  • Lee, Ki-Chang;Jeon, Jeong-Woo;Hwang, Don-Ha;Kim, Yong-Joo
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.535-538
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    • 2005
  • Today, most fixed-wing aircrafts are equipped with the antiskid brake system. It can modulate braking moments in the wheels optimally, when an aircraft is landing. So it can reduce landing distance and increase safeties. The antiskid brake system for an aircraft are mainly composed of braking moment modulators (hydraulic control valves) and brake control unit. In this paper, a Mark IV type - fully digital - brake controller is studied. For the development of its control algorithms, a 5-DOF (Degree of Freedom) aircraft landing model is composed in the form of matlab/simulink model at first. Then, braking moment control algorithms using wheel decelerations and slips are made. The developed algorithms are tested in software simulations using state-flow toolboxes in matlab/simulink model. Also, a real-time simulation systems are made, which use hydraulic brake systems of a real aircraft, pressure control valves and its controller as hardware components of HIL(Hardware In-the-Loop) simulation. Algorithms tested in software simulations are coded into the controller and the real-time landing simulations are made in very severe road conditions. The real-time simulation results are presented.

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A Study on a Reactive Power Control using Digital Filtering (디지털 필터링을 이용한 무효전력 제어에 관한 연구)

  • 우천희;강신준;이덕규;우광방;이성환
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.4
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    • pp.517-524
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    • 1998
  • This paper discusses the development of a reactive power controller using digital signal processing. Digital Signal Processing is the technique of using digital devices to Process continuous signals or data, often in real-time. And DSP algorithms are associated with a discrete time interval between input samples. When one designs a digital filter, one can use a Laplace transform to determine the continuous time frequency response. The corresponding discrete time transform is called Z transform and depends upon discrete samples of the input spaced equally in time. The objectives of this paper are to minimize real power losses and improve the power factor of a given system. Also, the implementation of a direct-form non recursive filter on the TMS320C31 has been described. The application of this microprocessor-based controller using DSP on test system reveals its numerous advantages. Performance and features of the controller for the reactive power control are analyzed.

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Design and implementation technique of real-time mechanism control language for programmable automation equipment (프로그래밍형 자동화기기를 위한 실시간 메카니즘 제어언어의 설계 및 구현기법)

  • 백정현;원용훈
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.11
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    • pp.29-38
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    • 1997
  • As the trend of the automation is increasing, the usage of the programmable automation equipments like programmable controller(PC), numerical controller(NC), distributed control systems(DCS) and robot controller is greatly expanding in the area of the industrial equipments. But the development of the programing language for the programmable automatic equipment is rarely accomplished. In this paper, we propose design and implementation technique of the real-time mechanism control language by adding time constraint constructs and timing analysis constructs ot conditional statement and iteration statement of a programming language. Moreover, we made it possible to predict plausibility of time constraint constructs of a real time application program at compilation time and developing execution time analysiss technique.

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Feedforward actuator controller development using the backward-difference method for real-time hybrid simulation

  • Phillips, Brian M.;Takada, Shuta;Spencer, B.F. Jr.;Fujino, Yozo
    • Smart Structures and Systems
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    • v.14 no.6
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    • pp.1081-1103
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    • 2014
  • Real-time hybrid simulation (RTHS) has emerged as an important tool for testing large and complex structures with a focus on rate-dependent specimen behavior. Due to the real-time constraints, accurate dynamic control of servo-hydraulic actuators is required. These actuators are necessary to realize the desired displacements of the specimen, however they introduce unwanted dynamics into the RTHS loop. Model-based actuator control strategies are based on linearized models of the servo-hydraulic system, where the controller is taken as the model inverse to effectively cancel out the servo-hydraulic dynamics (i.e., model-based feedforward control). An accurate model of a servo-hydraulic system generally contains more poles than zeros, leading to an improper inverse (i.e., more zeros than poles). Rather than introduce additional poles to create a proper inverse controller, the higher order derivatives necessary for implementing the improper inverse can be calculated from available information. The backward-difference method is proposed as an alternative to discretize an improper continuous time model for use as a feedforward controller in RTHS. This method is flexible in that derivatives of any order can be explicitly calculated such that controllers can be developed for models of any order. Using model-based feedforward control with the backward-difference method, accurate actuator control and stable RTHS are demonstrated using a nine-story steel building model implemented with an MR damper.

A Study on the Method of CAN Identifier assignment for Real-Time Network (실시간 네트워크를 위한 CAN 식별자 지정 방법에 관한 고찰)

  • 정의헌;이홍희
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.34-34
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    • 2000
  • One of the basic goals, when considering networks for communication in industrial control applications, is the reduction of complexity of related wiring harnesses. In addition, the networking offers the advantages for industrial control applications, such as ease of cabling, ease of changes in the cabling, ease of adding controller modules, etc. CAN (Controller Area Network) is generally applied in car networking in order to reduce the complexity of the related wiring harnesses. These traditional CAN application techniques are modified to achieve the real time communication for the industrial control applications. In this paper, we propose the method of CAN Identifier assignment for Real-Time network system. This method is can be used to scheduling messages on CAN for Real-Time network system. And also, the real-time network system is developed and the proposed moth(Ids are verified experimentally.

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Servo Motor Control by On-Off Controller with Hysterisis (히스테리시스를 갖는 온-오프 제어기에 의한 서보모터의 제어)

  • 김영복;김성환;양주호;정병건
    • Journal of Advanced Marine Engineering and Technology
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    • v.15 no.1
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    • pp.85-95
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    • 1991
  • All physical systems are nonlinear to some degree. The examples are relay, backlash, deadzone, saturation element and so on. In the linear control system design, it is useful method to restrict the nonlinearity to the linearity of system over the operation range. It is worth noting that nonlinearities may be intentionally introduced in to a system. A simple of an intentional non-linearity is the Bang-Bang controller which uses the On-Off relay. In this paper, an angular position servosystem made of a DC servomotor controlled by a microcomputer is discribed. Authors use two methods in the design of controller. The one is linear controller designed by the optimal feedback control theory only and the other is nonlinear controller designed by On-Off relay with optimal feedback control theory. To do the real time control, the controller is designed by using 16bit personal computer and A/D.D/A converter(12bit) is used in order to convert the signal. According to this way, the results from real time control are as follows. 2) Under the On-Off controller with hysterisis the influence of disturbance is considerably smaller than the linerar controller. 3) An increase in the sampling period has a destabilizing effect. 4)In the controller performance, the response time of the On-Off controller is longer than that of the linear controller. To close, we note that the On-Off controller with hysterisis is more attractive than the linear controller in the presence of the input limit.

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