• Structural Engineering and Mechanics
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• v.58 no.6
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• pp.1127-1143
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• 2016

The pounding phenomenon in adjacent structures happens in severing earthquakes that can cause great damages. Connecting neighboring structures with active and semi-active control devices is an effective method to avoid mutual colliding between neighboring buildings. One of the most important issues in control systems is applying online control force. There will be a time delay if the prose of producing control force does not perform on time. This paper proposed a time-delay compensation method in coupled structures control, with semi-active Magnetorheological (MR) damper. This method based on Newmark's integration is adopted to mitigate the time-delay effect. In this study, Lyapunov's direct approach is employed to compute demanded voltage for MR dampers. Using Lyapunov's direct algorithm guarantees the system stability to design a controller based on feedback. Because of the strong nonlinearity of MR dampers, the equation of motion of coupled structures becomes an involved equation, and it is impossible to solve it with the common time step methods. In present paper modified Newmark-Beta integration based on the instantaneous optimal control algorithm, used to solve the involved equation. In this method, the response of a coupled system estimated base on optimal control force. Two MDOF structures with different degrees of freedom are finally considered as a numeric example. The numerical results show, the Newmark compensation is an efficient method to decrease the negative effect of time delay in coupled systems; furthermore, instantaneous optimal control algorithm can estimate the response of structures suitable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.629-644
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• 2014

The goal of this paper is to consider a co-design approach between time delay compensation and the message scheduling for CAN-Based Networked Control Systems (NCS). First we propose a hybrid priority scheme for the message scheduling in order to improve the Quality of Service (QoS). Second we present the way to calculate the closed-loop communication time delay and then compensate this time delay using the pole placement design method in order to improve the Quality of Control (QoC). The final objective is the implementation of a co-design which is the combination of the compensation for communication time delays and the message scheduling in order to have a more efficient NCS design.

• Journal of Power Electronics
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• v.11 no.2
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• pp.156-162
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• 2011

The control loop time delay caused by sampling, the zero-order-holder effect and calculations is inevitable in the digital control of dc-dc switching converters. The time delay will limit the bandwidth of the control loop and therefore degrade the transient performance of digital systems. In this paper, the quantization time delay effects with different time delay values based on a generic second-order system are analyzed. The conclusion that the bandwidth of digital control is reduced by about 20% with a one cycle delay and by 50% with two cycles of delay in comparison with no time delay is obtained. To compensate the time delay and to increase the control loop bandwidth, a duty ratio predictive control scheme based on linear extrapolation is proposed. The compensation effect and a comparison of the load variation transient response characteristics with analogy control, conventional digital control and duty ratio predictive control with different time delay values are performed on a point-of-load Buck converter by simulations and experiments. It is shown that, using the proposed technique, the control loop bandwidth can be increased by 50% for a one cycle delay and 48.2% for two cycles of delay when compared to conventional digital control. Simulations and experimental results prove the validity of the conclusion of the quantization effects of the time delay and the proposed control scheme.

• 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.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.2
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• pp.149-154
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• 2000

The purpose of this study is to measure the compression temperature in cylinder by using the fine thermocouple. As for using the thermocouple, it's response time delay should be regarded, even if it is a fine one. So, the output of thermocouple needs some compensation. The compensation circuit, which consists of a differential and an adding circuit is used for the compensate the time lag. And the time constant of the compensation circuit is determined the time between the TDC and the maximum point of the thermocouple output. Using this compensation circuit, the compression temperature is investigated of the cylinder in the diesel engine.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.395-400
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• 2004

In most physical processes, the transfer function includes time-delay, and in the general distributed control system using computer network, there exists inherent time-delay caused by the spatial separation between controllers and actuators. This work deals with the synthesis of a discrete-time controller for a nonlinear system and proposes a new effective method to compensate the influence of input time-delay. The controller is synthesized by using input/output linearization. Under the circumstance that input time-delay exists, the system response has more overshoot and tends to diverge. For these reasons, the controller has to produce future input value that will be needed for the system. In order to calculate the future input value, some predictors are adopted. Using the discretization via Euler's method, numerical simulations about the Van der Pol system are performed to evaluate the performance of the proposed method.

• Journal of IKEEE
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• v.27 no.3
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• pp.234-238
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• 2023

In this paper, we propose a time-to-digital converter (TDC) with compensation capability for PVT (process, voltage, and temperature) variations. A typical delay line-based TDC measures time based on the inverter's propagation delay, making it fundamentally sensitive to PVT variations. This paper presents a method to minimize the resolution change of TDC by compensating for the propagation delay caused by the PVT variations. Additionally, it dopts Cyclic Vernier TDC (CVTDC) structure to provide a wide input detection range. The proposed CVTDC with PVT compensation function is designed using a 45nm CMOS process, consumes 8mW of power, offers a TDC resolution of 5 ps, and has an input detection range of about 5.1 ns.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.11
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• pp.953-957
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• 2001

This paper is concerned with a transfer alignment method for the SDINS under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonliner measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.486-486
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• 2000

This paper is concerned with a transfer alignment method for the SDINS(StrapDown Inertial Navigation System) under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.243-246
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• 1998

A predictive controller is designed based upon stochastic methods for compensation of network time delay which caused by the spatial separation between controllers and actuators. Current commands are generated by using time varying probability functions which can be defined according to the values of previous control inputs and actual outputs. To demonstrate the effect of this control methodology, simulation experiments are performed. The results show that even an unstabilized system by a long time delay can be stabilized with this predictive controller.