Active control of a nonlinear and hysteretic building structure with time delay

Liu, Kun,Chen, Long-Xiang,Cai, Guo-Ping Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.3

Time delay inevitably exists in active control systems, and it may cause the degradation of control efficiency or instability of the systems. So time delay needs to be compensated in control design in order to eliminate its negative effect on control efficiency. Today time delay in linear systems has been more studied and some treating methods had been worked out. However, there are few treating methods for time delay in nonlinear systems. In this paper, an active controller for a nonlinear and hysteretic building structure with time delay is studied. The nonlinear and hysteretic behavior of the system is illustrated by the Bouc-Wen model. By specific transformation and augmentation of state parameters, the motion equation of the system with explicit time delay is transformed into the standard state space representation without any explicit time delay. Then the fourth-order Runge-Kutta method and instantaneous optimal control method are applied to the controller design with time delay. Finally, numerical simulations and comparisons of an eight-story building using the proposed time-delay controller are carried out. Simulation results indicate that the control performance will deteriorate if time delay is not taken into account in the control design. The simulations also prove the proposed time delay controller in this paper can not only effectively compensate time delay to get better control effectiveness, but also work well with both small and large time delay problems.

Active control of a nonlinear and hysteretic building structure with time delay

Kun Liu,Long-Xiang Chen,Guo-Ping Cai 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.3

Time delay inevitably exists in active control systems, and it may cause the degradation of control efficiency or instability of the systems. So time delay needs to be compensated in control design in order to eliminate its negative effect on control efficiency. Today time delay in linear systems has been more studied and some treating methods had been worked out. However, there are few treating methods for time delay in nonlinear systems. In this paper, an active controller for a nonlinear and hysteretic building structure with time delay is studied. The nonlinear and hysteretic behavior of the system is illustrated by the Bouc-Wen model. By specific transformation and augmentation of state parameters, the motion equation of the system with explicit time delay is transformed into the standard state space representation without any explicit time delay. Then the fourth-order Runge-Kutta method and instantaneous optimal control method are applied to the controller design with time delay. Finally, numerical simulations and comparisons of an eight-story building using the proposed time-delay controller are carried out. Simulation results indicate that the control performance will deteriorate if time delay is not taken into account in the control design. The simulations also prove the proposed time delay controller in this paper can not only effectively compensate time delay to get better control effectiveness, but also work well with both small and large time delay problems.

Duty Ratio Predictive Control Scheme for Digital Control of DC-DC Switching Converters

Pengju Sun,Luowei Zhou 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.2

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.

Duty Ratio Predictive Control Scheme for Digital Control of DC-DC Switching Converters

Sun, Pengju,Zhou, Luowei The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.2

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.

Compensating time delay in semi-active control of a SDOF structure with MR damper using predictive control

Akbar Bathaei,Seyed Mehdi Zahrai 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.82 No.4

Some of the control systems used in engineering structures that use sensors and decision systems have some time delay reducing efficiency of the control system or even might make it unstable. In this research, in addition to considering the effect of the time delay in vibration control process, predictive control is used to compensate the time delay. A semi-active vibration control approach with the help of magneto-rheological dampers is implemented. In addition to using fuzzy inference system to determine the appropriate control voltage for MR damper, structural behavior prediction system and specifying future responses are also used such that the time delays occurring within control process are overcome. For this purpose, determination of prediction horizon is conducted for one, five, and ten steps ahead for single degree of freedom structures with periods ranging from 0.1 to 4 seconds, subjected to twenty earthquake excitations. The amount of time delay applied to the control system is 0.1 seconds. The obtained results indicate that for 0.1 second time delay, average prediction error values compared to the case without time delay is 3.47 percent. Having 0.1 second time delay in a semi-active control system reduces its efficiency by 11.46 percent; while after providing the control system with structure behavior prediction, the difference in the results for the control system without time delay is just 1.35 percent on average; indicating a 10.11 percent performance improvement for the control system.

The Design of PI with Delayed-Time Integral Mode Controller for Wireless Networked Control System

Warakon Jantapoon,Vittaya Tipsuwanporn,Arjin Numsomran 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

The problem of delay time and data packet loss in a wireless network control system causes a negative effect on the controller"s performance in reference tracking of the process variable. Therefore, this research presents the design of PI with a delayed-time integral mode controller for the wireless networked control system which adds a term of delay time to an integral control in the forward path to compensate the unnecessary integration of the controller, while supporting the control system to track the reference values continuously and efficiently. The performance tests are implemented in the first order plus dead time process, a vertical take-off landing (VTOL), which are controlled using IEEE 802.15.4 (Zigbee) wireless networks, and MATLAB, TrueTime 2.0 simulator by comparing the control system response with Predictive Proportional Integral (P-PI) and Smith Predictor controls. The results showed that with the disturbance conditions and packet loss at 60% the proposed technique, PI with delayed-time integral mode overcome the performance of other methods at a percentage overshoot of 2.3% and the integral absolute error (IAE) 0.8964 degrees.

퍼지논리를 이용한 제어 시스템 식별에 관한 연구

정형근,이상민 한국지식정보기술학회 2020 한국지식정보기술학회 논문지 Vol.15 No.5

This is a control system identification study using a fuzzy logic algorithm to handle the issue of the controller parameter tuning in a control system with time delay. Among the studies related to the controller parameter tuning for control system identification, Yunwana-Seborg's controller parameter tuning method showed a rapid response in plants with no time delay or with small-time delays due to the phase error caused by Pade's first-order approximation method. However, a large time delay causes a higher time delay estimate and it cannot be applied to the actual system. Zigler-Nichols' loop tuning method, which is widely applied in the industrial field, requires much time to tune controller parameters because it goes through many trials and errors. Although Cohen-Coon's controller parameter tuning method using the process response curve has an advantage of shortening the time required for controller parameter tuning than the Zigler-Nichols’s loop tuning method, it can only be applied to an open loop system. To overcome these shortcomings, Suh proposed to set a phase controller in Pade’s approximation method to reduce the phase error, between the estimated model transfer function while converting time delay into Pade’s first-order approximation and the time delay of an actual plant, as a controller parameter tuning. However, it has a disadvantage that it is not analytical because this method derives by substituting a phase regulator proportional to a constant value in time delay. This study discussed an analytical method that could solve the issue of the phase error between the actual plant and the estimated transfer function using a fuzzy logic algorithm. This study proved that the proposed method could overcome the shortcomings of causing the large time delay estimation and provide quick response and stability by suggesting a logical way to set up a phase regulator based on the comparisons of Zielger-Nichols' loop tuning method, Yunwana-Seborg's method, and the proposed controller parameter tuning method.

설계 사양을 고려한 제어시스템 식별

정형근,임동균 한국지식정보기술학회 2021 한국지식정보기술학회 논문지 Vol.16 No.6

The purpose of this study was to present a PID controller design that achieves high stability and robustness while satisfying a design specification(overshoot) required in the control system identification task under condition of time delay. In the control system identification task, Yunwana-Seborg's control system identification tuning method and Zigler-Nichols' method ensure high performance and stability when they are applied to a system with short time delay since they have less error between time delay of estimated transfer function and real one. However, they are not applicable to system with high time delay since, when they are applied to such system, they have bigger error between time delay of estimated transfer function derived by Pade’1’st approximation method and real one. Zigler-Nichols loop tuning method, which has been applied in many parts of the industry, undergoes control parameter tuning through many trial and error, therefore takes longer time compared to other controller design methods. The control parameter tuning method using the process response curve proposed by Cohen-Coon has the advantage of less tuning time compared to the loop tuning method, however is applicable only to open loop system but not to close loop system. The method proposed by Suh, which modified Yunwana-Seborg's control system identification tuning method, to overcome the shortcomings of the close loop system and method using the processor response curve, presented the control parameter tuning to reduce the error between time delay of estimated transfer function derived by Pade’1’st approximation method and real one. This method was derived by setting a phase regulator proportional to the delay constant value at the time delay and ensured satisfactory stability and performance, but was not analytic. The PID controller design proposed in this paper ensures a performance and stability by overcoming the error between time delay of estimated transfer function and real one occurring at actual plant and determining the phase regulator in the initial design stage through considering a design specification(overshoot) required by control system.

Measurement of Delay Time in Communication Channels by Anfis

Seyed Mohammad Amir Hosseinipa 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

The use of teleoperation in remote locations allows humans to extend their capabilities to distant and hazardous environments. Although safer for the operator, this extension of capabilities comes at a price. Due to communication across great distances, experiencing delay times of up to several milliseconds is common. In teleoperation systems, delay time in communication channel may distort the signals, and can lead to system instability. So that any delay time in the human/robot interaction can significantly degrade the effectiveness of operator control. By prediction of delay time in the Internet, we can use new structures for creating high performance systems in teleportation systems. This paper describes a new method for prediction of delay time in the Internet. An Anfis is proposed for the prediction of delay time. By using measured data (delay time between two universities) in Transmission Control protocol (TCP), the Anfis was trained. Then, using validation data, the performance of the Anfis was evaluated. It is shown that this Anfis can predict delay time based on their proper inputs.

Active control of a flexible structure with time delay

Cai, Guo-Ping,Yang, Simon X. Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.2

Time delay exists inevitably in active control, which may not only degrade the system performance but also render instability to the dynamic system. In this paper, a novel active controller is developed to solve the time delay problem in flexible structures. By using the independent modal space control method, the differential equation of the controlled mode with time delay is obtained from the time-delay system dynamics. Then it is discretized and changed into a first-order difference equation without any explicit time delay by augmenting the state variables. The modal controller is derived based on the augmented system using the discrete variable structure control method. The switching surface is determined by minimizing a discrete quadratic performance index. The modal coordinate is extracted from sensor measurements and the actuator control force is converted from the modal one. Since the time delay is explicitly included throughout the entire controller design without any approximation, the system performance and stability are guaranteed. Numerical simulations show that the proposed controller is feasible and effective in active vibration control of dynamic systems with time delay. If the time delay is not explicitly included in the controller design, instability may occur.