Performance enhancement of pneumatic vibration isolation tables in low frequency range by time delay control

2009 ◽  
Vol 321 (3-5) ◽  
pp. 537-553 ◽  
Author(s):  
Yun-Ho Shin ◽  
Kwang-Joon Kim
Keyword(s):  
Time Delay ◽  
Vibration Isolation ◽  
Performance Enhancement ◽  
Low Frequency ◽  
Frequency Range ◽  
Time Delay Control ◽  
Delay Control

Three Degrees of Freedom Active Control of Pneumatic Vibration Isolation Table by Pneumatic and Time Delay Control Technique

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Yun-Ho Shin ◽  
Kwang-Joon Kim ◽  
Pyung-Hoon Chang ◽  
Dong Ki Han
Keyword(s):  
Time Delay ◽  
Active Control ◽  
Vibration Isolation ◽  
Decomposition Analysis ◽  
Second Order ◽  
Pneumatic Actuator ◽  
Control Technique ◽  
Order System ◽  
Time Delay Control ◽  
Delay Control

Based on previous feasibility study on one degree of freedom (1DOF) pneumatic active control of pneumatic springs, this paper presents procedures and results of a more realistic 3DOF active control of a pneumatic vibration isolation table. The 3DOF motion of the pneumatic table, consisting of heaving, rolling, and pitching, is controlled directly by adjusting air pressure in four pneumatic cylinders in a dynamic manner with pneumatic valves, without any external actuator such as an electromagnet or voice coil. The time delay control, which is a software chosen in this study, together with the hardware, i.e., the pneumatic actuator, is shown to be very powerful in enhancing the performance of vibration isolation for ground excitation as well as in settling time reduction for payload excitation through simulations and measurements on the 3DOF motion control system. New key results found in the experimental approach are that the pneumatic actuator shows a dynamic behavior of a second-order system, instead of a first-order system, which has been used in existing literatures so far, and that just feed-forward control of the pneumatic actuator by the second-order model can compensate for the inherently slow response characteristics of the pneumatic actuator very successfully. Effectiveness of the proposed active pneumatic control technique in the multi-input and multi-output system is shown via singular value decomposition analysis on the transmissibility matrix. Promising future of the proposed control and performance analysis technique is further discussed based on the results in the case of payload excitations as well.

scholarly journals Line Spectrum Chaotification on QZS Systems with Time-Delay Control

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jing Zhang ◽  
Tao Tang ◽  
Wenhua Fang
Keyword(s):  
Comparative Analysis ◽  
Time Delay ◽  
Numerical Simulations ◽  
Vibration Isolation ◽  
Line Spectrum ◽  
New Approach ◽  
Time Delay Control ◽  
Control Gain ◽  
Delay Control ◽  
Isolation Systems

Chaotification can be employed to weaken or eliminate the feature of line spectra of waterborne noise. The efficiency of this method lies on the use of small control. The analysis reveals that the critical control gain depends on the stiffness of vibration isolation systems. Thus, an isolation raft system based on quasi-zero-stiffness (QZS) property is proposed for line spectrum chaotification. A nonlinear time-delay controller is derived accordingly. Comparative analysis shows that the new approach allows much smaller control, and the intensity of line spectra is further reduced. Numerical simulations also indicate other advantages with the introduction of QZS system into chaotification.

scholarly journals Study on the Performance of a Quasi-Zero-Stiffness Isolator with Time Delay Control

2018 ◽  
Vol 36 (6) ◽  
pp. 1168-1175
Author(s):  
Donghai Li ◽  
Shougen Zhao ◽  
Yujin He ◽  
Tao Li
Keyword(s):  
Time Delay ◽  
Vibration Isolation ◽  
Linear Displacement ◽  
Dynamical Response ◽  
High Frequency Region ◽  
Time Delay Control ◽  
Delay Control ◽  
Force Transmissibility ◽  
Feedback Control Strategy ◽  
Better Than

A quasi-zero-stiffness vibration isolation consists of a pair of oblique springs and a vertical spring, aiming at widening the vibration isolation region, is studied in this paper. The time delay linear displacement feedback control strategy is introduced to improve the performance of the isolator. The characteristics of dynamical response under harmonically forcing excitation is obtained by using averaging method. The force transmissibility of the control isolator is presented in this paper. The influence of the time delay linear displacement control on the force transmissibility is studied theoretically. The results show that the performance of the vibration isolation with time-delay control is better than the equivalent linear isolator in either low or high frequency region and the performance of controlled system is better than uncontrolled system.

scholarly journals Time-delay control for stabilization of the Shapovalov mid-size firm model

2020 ◽  
Vol 53 (2) ◽  
pp. 16971-16976
Author(s):  
T.A. Alexeeva ◽  
W.A. Barnett ◽  
N.V. Kuznetsov ◽  
T.N. Mokaev
Keyword(s):  
Time Delay ◽  
Time Delay Control ◽  
Delay Control ◽  
Size Firm ◽  
Firm Model

scholarly journals Robust-adaptive dynamic programming-based time-delay control of autonomous ships under stochastic disturbances using an actor-critic learning algorithm

2021 ◽  
Author(s):  
Hossein Nejatbakhsh Esfahani ◽  
Rafal Szlapczynski
Keyword(s):  
Dynamic Programming ◽  
Time Delay ◽  
Control Algorithm ◽  
Approximate Dynamic Programming ◽  
Robust Adaptive Control ◽  
Stochastic Disturbances ◽  
Time Delay Control ◽  
Model Free ◽  
Delay Control ◽  
Robust Adaptive

AbstractThis paper proposes a hybrid robust-adaptive learning-based control scheme based on Approximate Dynamic Programming (ADP) for the tracking control of autonomous ship maneuvering. We adopt a Time-Delay Control (TDC) approach, which is known as a simple, practical, model free and roughly robust strategy, combined with an Actor-Critic Approximate Dynamic Programming (ACADP) algorithm as an adaptive part in the proposed hybrid control algorithm. Based on this integration, Actor-Critic Time-Delay Control (AC-TDC) is proposed. It offers a high-performance robust-adaptive control approach for path following of autonomous ships under deterministic and stochastic disturbances induced by the winds, waves, and ocean currents. Computer simulations have been conducted under two different conditions in terms of the deterministic and stochastic disturbances and all simulation results indicate an acceptable performance in tracking of paths for the proposed control algorithm in comparison with the conventional TDC approach.

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