• Title/Summary/Keyword: delay compensation

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Time Delay Compensation for Output Voltage Vector Selection in Direct Torque Control of Induction Machine (유도전동기의 직접토크제어 시스템에서 출력전압벡터선정을 위한 시간지연의 보상)

  • 최병태;박철우;권우현
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.8
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    • pp.632-639
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    • 2003
  • This paper proposes a simple compensation scheme for the time delay caused by measurement, calculation and selection of voltage vector in Direct Torque Control (DTC) of an induction motor. In general scheme, it is difficult to know the exact delay time, furthermore the delay time can be varied by program routines for calculation and processing of measured data. In this proposed scheme, by applying voltage vector at the beginning of next sampling period, a fixed delay time is achieved and its compensation becomes much simpler. Furthermore, with the simple compensation algorithm, an improved performance can be achieved by shortening sampling period. Experimental results prove the feasibility of the proposed scheme in induction motor control.

Adaptive Time Delay Compensation Process in Networked Control System

  • Kim, Yong-Gil;Moon, Kyung-Il
    • International journal of advanced smart convergence
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    • v.5 no.1
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    • pp.34-46
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    • 2016
  • Networked Control System (NCS) has evolved in the past decade through the advances in communication technology. The problems involved in NCS are broadly classified into two categories namely network issues due to network and control performance due to system network. The network problems are related to bandwidth allocation, scheduling and network security, and the control problems deal with stability analysis and delay compensation. Various delays with variable length occur due to sharing a common network medium. Though most delays are very less and mostly neglected, the network induced delay is significant. It occurs when sensors, actuators, and controllers exchange data packet across the communication network. Networked induced delay arises from sensor to controller and controller to actuator. This paper presents an adaptive delay compensation process for efficient control. Though Smith predictor has been commonly used as dead time compensators, it is not adaptive to match with the stochastic behavior of network characteristics. Time delay adaptive compensation gives an effective control to solve dead time, and creates a virtual environment using the plant model and computed delay which is used to compensate the effect of delay. This approach is simulated using TrueTime simulator that is a Matlab Simulink based simulator facilitates co-simulation of controller task execution in real-time kernels, network transmissions and continuous plant dynamics for NCS. The simulation result is analyzed, and it is confirmed that this control provides good performance.

Development of a New Moving Obstacle Avoidance Algorithm using a Delay-Time Compensation for a Network-based Autonomous Mobile Robot (네트워크 기반 자율 이동 로봇을 위한 시간지연 보상을 통한 새로운 동적 장애물 회피 알고리즘 개발)

  • Kim, Dong-Sun;Oh, Se-Kwon;Kim, Dae-Won
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1916-1917
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    • 2011
  • A development of a new moving obstacle avoidance algorithm using a delay-time Compensation for a network-based autonomous mobile robot is proposed in this paper. The moving obstacle avoidance algorithm is based on a Kalman filter through moving obstacle estimation and a Bezier curve for path generation. And, the network-based mobile robot, that is a unified system composed of distributed environmental sensors, mobile actuators, and controller, is compensated by a network delay compensation algorithm for degradation performance by network delay. The network delay compensation method by a sensor fusion using the Kalman filter is proposed for the localization of the robot to compensate both the delay of readings of an odometry and the delay of reading of environmental sensors. Through some simulation tests, the performance enhancement of the proposed algorithm in the viewpoint of efficient path generation and accurate goal point is shown here.

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An adaptive delay compensation method based on a discrete system model for real-time hybrid simulation

  • Wang, Zhen;Xu, Guoshan;Li, Qiang;Wu, Bin
    • Smart Structures and Systems
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    • v.25 no.5
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    • pp.569-580
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    • 2020
  • The identification of delays and delay compensation are critical problems in real-time hybrid simulations (RTHS). Conventional delay compensation methods are mostly based on the assumption of a constant delay. However, the system delay may vary during tests owing to the nonlinearity of the loading system and/or the behavioral variations of the specimen. To address this issue, this study presents an adaptive delay compensation method based on a discrete model of the loading system. In particular, the parameters of this discrete model are identified and updated online with the least-squares method to represent a servo hydraulic loading system. Furthermore, based on this model, the system delays are compensated for by generating system commands using the desired displacements, achieved displacements, and previous displacement commands. This method is more general than the existing compensation methods because it can predict commands based on multiple displacement categories. Moreover, this method is straightforward and suitable for implementation on digital signal processing boards because it relies solely on the displacements rather than on velocity and/or acceleration data. The virtual and real RTHS results show that the studied method exhibits satisfactory estimation smoothness and compensation accuracy. Furthermore, considering the measurement noise, the low-order parameter models of this method are more favorable than that the high-order parameter models.

Compensation Technique of Measurement Time Delay in Transfer Alignment Using the Double Moving Window Buffer (이중 Moving Window 버퍼 기반 전달정렬 측정치 시간지연 보상기법)

  • Kim, Cheon-Joong;Lyou, Joon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.4
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    • pp.684-693
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    • 2011
  • Measurement time delay in the transfer alignment is very important. It has been well known that the time delay degrades the alignment performance and makes some navigation errors on the transfer alignment of slave INS(SINS). Therefore there are many schemes to eliminate that time delay but the compensation technique through the estimation by Kalman filter through modeling the time delay as a random constant is generally used. In the case of change over measurement time delay or the large measurement time delay, estimation performance in the existing compensation technique is degraded because model of time delay is not correct any more. In this paper, we propose the method to keep the time delay almost constant even though in the abnormal communication state and very small through feedback compensation using double buffer. Double buffer consists of two moving window to temporarily store measurements from master INS and slave INS in real time.

Improvement of Residual Delay Compensation Algorithm of KJJVC (한일상관기의 잔차 지연 보정 알고리즘의 개선)

  • Oh, Se-Jin;Yeom, Jae-Hwan;Roh, Duk-Gyoo;Oh, Chung-Sik;Jung, Jin-Seung;Chung, Dong-Kyu;Oyama, Tomoaki;Kawaguchi, Noriyuki;Kobayashi, Hideyuki;Kawakami, Kazuyuki;Ozeki, Kensuke;Onuki, Hirohumi
    • Journal of the Institute of Convergence Signal Processing
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    • v.14 no.2
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    • pp.136-146
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    • 2013
  • In this paper, the residual delay compensation algorithm is proposed for FX-type KJJVC. In case of initial version as that design algorithm of KJJVC, the integer calculation and the cos/sin table for the phase compensation coefficient were introduced in order to speed up of calculation. The mismatch between data timing and residual delay phase and also between bit-jump and residual delay phase were found and fixed. In final design of KJJVC residual delay compensation algorithm, the initialization problem on the rotation memory of residual delay compensation was found when the residual delay compensated value was applied to FFT-segment, and this problem is also fixed by modifying the FPGA code. Using the proposed residual delay compensation algorithm, the band shape of cross power spectrum becomes flat, which means there is no significant loss over the whole bandwidth. To verify the effectiveness of proposed residual delay compensation algorithm, we conducted the correlation experiments for real observation data using the simulator and KJJVC. We confirmed that the designed residual delay compensation algorithm is well applied in KJJVC, and the signal to noise ratio increases by about 8%.

The Implementation of the Compensation Algorithm of Time Delay for Microwave Polar Transmitters (마이크로파 폴라 송신기의 시간지연 보상 알고리즘 구현)

  • Kim, Min-Soo;Lee, Kun-Joon;Rhee, Young-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.9
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    • pp.790-797
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    • 2015
  • In this paper, We made the microwave polar transmitter based on the software to analyze the synchronization status between the phase signal and the amplitude signal of polar transmitter, and analyzed the result. In order to solve the time delay mismatch problem, we applied simplified compensation algorithm and compared the synchronization status between the two paths before and after compensation. Before compensation, the value of time delay mismatch was the maximum of 97 nsec at 9.3 GHz with the occupied bandwidth of 12 MHz, but after applying the compensation algorithm, the signals between the two paths were synchronized, and we identified the occupied bandwidth could recover to the previous 3.7 MHz.

Compensation for temperature-level control of tanked water system with time delay

  • Nakamura, Masatoshi;Watanabe, Kiyoto
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10b
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    • pp.42-47
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    • 1993
  • Importance of separation of a nonlinear dynamical system into nonlinear static part and linear dynamical part was insisted in designing a controller for the nonlinear system. We further proposed compensation techniques for oscillation of controlled variables caused by system time delay and compensation of steady state errors caused by modelling errors of the systems. The proposed principle of designing procedure and the compensation methods were discussed by applying them for temperature and level control of an actual tanked water system.

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Real-time hybrid testing using model-based delay compensation

  • Carrion, Juan E.;Spencer, B.F. Jr.
    • Smart Structures and Systems
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    • v.4 no.6
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    • pp.809-828
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    • 2008
  • Real-time hybrid testing is an attractive method to evaluate the response of structures under earthquake loads. The method is a variation of the pseudodynamic testing technique in which the experiment is executed in real time, thus allowing investigation of structural systems with time-dependent components. Real-time hybrid testing is challenging because it requires performance of all calculations, application of displacements, and acquisition of measured forces, within a very small increment of time. Furthermore, unless appropriate compensation for time delays and actuator time lag is implemented, stability problems are likely to occur during the experiment. This paper presents an approach for real-time hybrid testing in which time delay/lag compensation is implemented using model-based response prediction. The efficacy of the proposed strategy is verified by conducting substructure real-time hybrid testing of a steel frame under earthquake loads. For the initial set of experiments, a specimen with linear-elastic behavior is used. Experimental results agree well with the analytical solution and show that the proposed approach and testing system are capable of achieving a time-scale expansion factor of one (i.e., real time). Additionally, the proposed method allows accurate testing of structures with larger frequencies than when using conventional time delay compensation methods, thus extending the capabilities of the real-time hybrid testing technique. The method is then used to test a structure with a rate-dependent energy dissipation device, a magnetorheological damper. Results show good agreement with the predicted responses, demonstrating the effectiveness of the method to test rate-dependent components.