scholarly journals Multiple-TMD-Based Structural Vibration Control for Pumped Storage Power Plants

2020 ◽  
Vol 10 (16) ◽  
pp. 5577
Author(s):  
Tengfei Zhong ◽  
Xin Feng ◽  
Yu Zhang ◽  
Jing Zhou
Keyword(s):  
Vibration Control ◽  
High Frequency ◽  
Power Plants ◽  
Control Method ◽  
Control Strategies ◽  
High Order Mode ◽  
Structural Vibration ◽  
Power Station ◽  
High Frequency Vibration ◽  
Pumped Storage

The high-frequency resonance in the superstructure of a pumped storage power station (PSPP) due to the generation unit can shorten the service life of the power station structure and even endanger its safety. Although tuned mass dampers (TMDs) have been proved to be effective in controlling structural vibration, their application in PSPPs is rare, as high-frequency vibration control of PSPPs has not been studied. In this paper, a TMD control method is proposed based on PSPP high-frequency vibration and various TMD control strategies, and a set of high-frequency TMD equipment is designed. Results of a series of vibration reduction tests and numerical analyses show that the new TMD device can effectively control the high-order mode of the structure, and the bandwidth of the suppression frequency is extended, which shows the robustness and control efficiency of the device.

Diagonal Recurrent Neural Networks for MDOF Structural Vibration Control

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Z. Q. Gu ◽  
S. O. Oyadiji
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Control Strategies ◽  
Linear Quadratic Regulator ◽  
Pole Placement ◽  
Structural Vibration ◽  
Stability And Convergence ◽  
Northridge Earthquake ◽  
Linear Quadratic ◽  
Structural Vibration Control

In recent years, considerable attention has been paid to the development of theories and applications associated with structural vibration control. Integrating the nonlinear mapping ability with the dynamic evolution capability, diagonal recurrent neural network (DRNN) meets the needs of the demanding control requirements in increasingly complex dynamic systems because of its simple and recurrent architecture. This paper presents numerical studies of multiple degree-of-freedom (MDOF) structural vibration control based on the approach of the backpropagation algorithm to the DRNN control method. The controller’s stability and convergence and comparisons of the DRNN method with conventional control strategies are also examined. The numerical simulations show that the structural vibration responses of linear and nonlinear MDOF structures are reduced by between 78% and 86%, and between 52% and 80%, respectively, when they are subjected to El Centro, Kobe, Hachinohe, and Northridge earthquake processes. The numerical simulation shows that the DRNN method outperforms conventional control strategies, which include linear quadratic regulator (LQR), linear quadratic Gaussian (LQG) (based on the acceleration feedback), and pole placement by between 20% and 30% in the case of linear MDOF structures. For nonlinear MDOF structures, in which the conventional controllers are ineffective, the DRNN controller is still effective. However, the level of reduction of the structural vibration response of nonlinear MDOF structures achievable is reduced by about 20% in comparison to the reductions achievable with linear MDOF structures.

scholarly journals A Variable Parameter Ambient Vibration Control Method Based on Quasi-Zero Stiffness in Robotic Drilling Systems

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 67
Author(s):  
Laixi Zhang ◽  
Chenming Zhao ◽  
Feng Qian ◽  
Jaspreet Singh Dhupia ◽  
Mingliang Wu
Keyword(s):  
Vibration Control ◽  
Vibration Isolation ◽  
Control Method ◽  
Control Strategies ◽  
Equations Of Motion ◽  
Variable Parameter ◽  
Harmonic Balance Method ◽  
Variable Stiffness ◽  
Ambient Vibration ◽  
Robotic Drilling

Vibrations in the aircraft assembly building will affect the precision of the robotic drilling system. A variable stiffness and damping semiactive vibration control mechanism with quasi-zero stiffness characteristics is developed. The quasi-zero stiffness of the mechanism is realized by the parallel connection of four vertically arranged bearing springs and two symmetrical horizontally arranged negative stiffness elements. Firstly, the quasi-zero stiffness parameters of the mechanism at the static equilibrium position are obtained through analysis. Secondly, the harmonic balance method is used to deal with the differential equations of motion. The effects of every parameter on the displacement transmissibility are analyzed, and the variable parameter control strategies are proposed. Finally, the system responses of the passive and semiactive vibration isolation mechanisms to the segmental variable frequency excitations are compared through virtual prototype experiments. The results show that the frequency range of vibration isolation is widened, and the stability of the vibration control system is effectively improved without resonance through the semiactive vibration control method. It is of innovative significance for ambient vibration control in robotic drilling systems.

The Investigation of the Optimization Scheme of the Low-cycle Fatigue Cropping Based on the Acoustic Emission Technique

2021 ◽  
Author(s):  
Yujian Ren ◽  
Jingxiang Li ◽  
Yuanzhe Dong ◽  
Dong Jin ◽  
Shengdun Zhao
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
Control Method ◽  
Low Cycle Fatigue ◽  
Control Strategies ◽  
Low Frequency ◽  
Loading Frequency ◽  
Cycle Fatigue ◽  
Al 6061 ◽  
Whole Process

Abstract High efficiency and good section quality are two main objectives of metal bar cropping. A suitable control method can help to achieve both goals. An investigation of the control method of low-cycle fatigue cropping (LCFC) based on the acoustic emission (AE) technique has been proposed in this study. Ring-down counts and kurtosis are used to monitor the whole process of LCFC. The results showed that kurtosis is more suitable for monitoring the LCFC process and as a critical parameter to optimize the control method than ring-down counts in the noisy factory environment.Moreover, three types of materials are studied in this experiment; by combine with the AE results, macroscopic images and microscopic images of sections, characteristics of various LCFC stages are obtained. The results also indicated reduce the area of the transient fracture zone is the key to improve the section quality. Reducing the load frequency before the unstable crack propagation stage will beneficial to realize the goals. Based on the evaluation of kurtosis, an optimized control method is presented, and two control parameters: transient time T and the critical value of the slope of kurtosis C are determined. For 16Mn, 1045 and Al 6061, the T is 5s, 10s, and 1s, respectively. For 16Mn, 1045, and Al 6061, the C is 100, 300, and 0, respectively. Two parameters, h and S, are used to evaluate the section quality and four control strategies are compared. The results indicate the optimal control methods can improve the section quality effectively. The influence trend of reducing loading frequency is investigated by further comparison. It can be seen as the frequency decreases, the efficiency of the section quality improving decreases. In order to realize the optimal results, different control strategies are adopted for different materials. Strategy 1 (high frequency is 20Hz，high frequency thought the whole process), strategy 2 (high frequency is 20Hz，low frequency is 8.33Hz), and strategy 3 (high frequency is 20Hz，low frequency is 6.67Hz) is suitable for Al 6061, 1045, and 16Mn, respectively.

scholarly journals Present Status and Prospect of High-Frequency Electro-hydraulic Vibration Control Technology

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Yi Liu ◽  
Tao Wang ◽  
Guofang Gong ◽  
Rujun Gao
Keyword(s):  
Vibration Control ◽  
High Frequency ◽  
Seismic Waves ◽  
Stability Control ◽  
Control Technology ◽  
Rotary Valve ◽  
High Frequency Vibration ◽  
Vibration Method ◽  
Waveform Distortion ◽  
Control Stability

AbstractElectro-hydraulic vibration equipment (EHVE) is widely used in vibration environment simulation tests, such as vehicles, weapons, ships, aerospace, nuclear industries and seismic waves replication, etc., due to its large output power, displacement and thrust, as well as good workload adaptation and multi-controllable parameters. Based on the domestic and overseas development of high-frequency EHVE, dividing them into servo-valve controlled vibration equipment and rotary-valve controlled vibration equipment. The research status and progress of high-frequency electro-hydraulic vibration control technology (EHVCT) are discussed, from the perspective of vibration waveform control and vibration controller. The problems of current electro-hydraulic vibration system bandwidth and waveform distortion control, stability control, offset control and complex vibration waveform generation in high-frequency vibration conditions are pointed out. Combining the existing rotary-valve controlled high-frequency electro-hydraulic vibration method, a new twin-valve independently controlled high-frequency electro-hydraulic vibration method is proposed to break through the limitations of current electro-hydraulic vibration technology in terms of system frequency bandwidth and waveform distortion. The new method can realize independent adjustment and control of vibration waveform frequency, amplitude and offset under high-frequency vibration conditions, and provide a new idea for accurate simulation of high-frequency vibration waveform.

scholarly journals Analyses of the Control System Strategies and Methodology for Part Power Control of the Simple and Intercooled Recuperated Brayton Helium Gas Turbine Cycles for Generation IV Nuclear Power Plants

2017 ◽  
Vol 3 (4) ◽  
Author(s):  
A. Gad-Briggs ◽  
P. Pilidis ◽  
T. Nikolaidis
Keyword(s):  
Control System ◽  
Inventory Control ◽  
Nuclear Power ◽  
Power Plants ◽  
Control Method ◽  
Control Strategies ◽  
Limiting Factors ◽  
Cycle Performance ◽  
Study Results ◽  
And Performance

An important requirement for Generation IV Nuclear Power Plant (NPP) design is the control system, which enables part power operability. The choices of control system methods must ensure variation of load without severe drawbacks on cycle performance. The objective of this study is to assess the control of the NPP under part power operations. The cycles of interest are the simple cycle recuperated (SCR) and the intercooled cycle recuperated (ICR). Control strategies are proposed for NPPs but the focus is on the strategies that result in part power operation using the inventory control method. First, results explaining the performance and load limiting factors of the inventory control method are documented; subsequently, the transient part power performances are also documented. The load versus efficiency curves were also derived from varying the load to understand the efficiency penalties. This is carried out using a modeling and performance simulation tool designed for this study. Results show that the ICR takes ∼102% longer than the SCR to reduce the load to 50% in design point (DP) performance conditions for similar valve flows, which correlates with the volumetric increase for the ICR inventory tank. The efficiency penalties are comparable for both cycles at 50% part power, whereby a 22% drop in cycle efficiency was observed and indicates limiting time at very low part power. The analyses intend to aid the development of cycles for Generation IV NPPs specifically gas cooled fast reactors (GFRs) and very high-temperature reactors (VHTRs), where helium is the coolant.

scholarly journals Overlapping Decentralized Control Strategies of Building Structures’ Vibration with Time Delay Based on H∞ Control Algorithms under Seismic Excitation

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaofang Kang ◽  
Jian Wu ◽  
Yewei Zhang ◽  
Guoliang Liu ◽  
Suhui Zhang ◽  
...  
Keyword(s):  
Control System ◽  
Time Delay ◽  
Vibration Control ◽  
Decentralized Control ◽  
Control Strategy ◽  
Control Algorithm ◽  
Control Method ◽  
Control Strategies ◽  
Linear Matrix ◽  
Feedback Gain

A decentralized control strategy can effectively solve the control problem of the large-scale time delayed structures. In this paper, combining the overlapping decentralized control method, linear matrix inequality (LMI) method, and H∞ control algorithm, overlapping decentralized H∞ control approach of the time delayed structures has been established. The feedback gain matrixes of all subsystems are obtained by this method based on genetic algorithm optimization tools and the specific goal of optimization control. The whole vibration control system of the time delayed structures is divided into a series of overlapping subsystems by overlapping decentralized control strategy. The feedback gain matrixes of each subsystem can be obtained by using H∞ control algorithm to calculate each subsystem. The vibration control of a twenty layers’ antiseismic steel structure Benchmark model was analyzed with the numerical method. The results show that the proposed method can be applied to control system with time delay. The overlapping decentralized control strategies acquire the similar control effects with that of the centralized control strategy. Moreover, the flexibility of the controller design has been enhanced by using overlapping decentralized control strategies.

Dynamic Walk of a Quadruped Locomotion Robot Using Robust Optimal Tracking Control

1995 ◽  
Author(s):  
Hiroaki Uchida ◽  
Kenzo Nonami
Keyword(s):  
Optimal Control ◽  
High Frequency ◽  
Tracking Control ◽  
Control Method ◽  
Reaction Force ◽  
The Body ◽  
High Frequency Vibration ◽  
Quadruped Locomotion ◽  
Optimal Tracking ◽  
Optimal Tracking Control

Abstract We propose a new control system design strategy that is called “frequency-shaped optimal tracking control method” in this paper. We make sure that the proposed method is very useful by creating the quasi-dynamic walk of a quadruped locomotion robot. During control of the locomotion robot, high feedback (FB) gains should be selected to work against the force and the moment from the body and the reaction force from the ground. However, if high FB gains are used, high frequency vibration comes out because of the backlash of the gear. Frequency-shaped optimal control is the control method to improve the robustness against the disturbance like high frequency vibration. Frequency-shaped optimal tracking control extends the frequency-shaped optimal control to the servo system like the trajectory following control of the robot. First, we’ll show the design scheme of the frequency-shaped optimal tracking control. Next, we’ll show how decentralized control is realized in order to apply frequency-shaped optimal tracking control. Finally, we’ll compare the frequency-shaped optimal tracking control with the optimal tracking control from the points of view of the simulations and the experiments.

ACTIVE VIBRATION CONTROL OF SEISMICALLY EXCITED STRUCTURES BY ATMDS: STABILITY AND PERFORMANCE ROBUSTNESS PERSPECTIVE

2010 ◽  
Vol 10 (03) ◽  
pp. 501-527 ◽  
Author(s):  
ARASH MOHTAT ◽  
AGHIL YOUSEFI-KOMA ◽  
EHSAN DEHGHAN-NIRI
Keyword(s):  
Vibration Control ◽  
Structural Damage ◽  
Fuzzy Logic Controller ◽  
Control Strategies ◽  
Linear Quadratic Regulator ◽  
Pole Placement ◽  
Structural Vibration ◽  
Linear Quadratic ◽  
And Performance ◽  
Performance Robustness

This paper demonstrates the trade-off between nominal performance and robustness in intelligent and conventional structural vibration control schemes; and, proposes a systematic treatment of stability robustness and performance robustness against uncertainty due to structural damage. The adopted control strategies include an intelligent genetic fuzzy logic controller (GFLC) and reduced-order observer-based (ROOB) controllers based on pole-placement and linear quadratic regulator (LQR) conventional schemes. These control strategies are applied to a seismically excited truss bridge structure through an active tuned mass damper (ATMD). Response of the bridge-ATMD control system to earthquake excitation records under nominal and uncertain conditions is analyzed via simulation tests. Based on these results, advantages of exploiting heuristic intelligence in seismic vibration control, as well as some complexities arising in realistic conventional control are highlighted. It has been shown that the coupled effect of spill-over (due to reduction and observation) and mismatch between the mathematical model and the actual plant (due to uncertainty and modeling errors) can destabilize the conventional closed-loop system even if each is alone tolerated. Accordingly, the GFLC proves itself to be the dominant design in terms of the compromise between performance and robustness.

Study on the Management Model of Pumped Storage Power Station

2013 ◽  
Vol 860-863 ◽  
pp. 2622-2626
Author(s):  
Yan Qing Li ◽  
Chi Dong ◽  
Hao Shan Li ◽  
Zhi Fei Liang
Keyword(s):  
Power Generation ◽  
Nuclear Power ◽  
Power Plants ◽  
Business Models ◽  
Thermal Power ◽  
Management Model ◽  
Environmental Benefit ◽  
Power Station ◽  
The Government ◽  
Pumped Storage

Power generation business models relate to the sustainable development of generation companies. This paper proposes an improved united lease management model for pumped storage power stations. Grid company, power generation companies (thermal power plants and nuclear power plants), and the government department jointly bear the rental fee. The amount of lease fees is determined according to the benefit of each renter. This paper conducted a case study of Huizhou Pumped Storage Power Station. The united power system simulation and auxiliary services compensation were applied to calculate the generation benefit, environmental benefit and dynamic benefit. The results suggest that the total incomes of Huizhou Pumped Storage Power Station are increased and the rental fee is fair and reasonable, indicating the rationality and effectiveness of this new management model.

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