scholarly journals Acceleration Harmonics Identification for an Electro-Hydraulic Servo Shaking Table based on a Nonlinear Adaptive Algorithm

2018 ◽  
Author(s):  
Jianjun Yao ◽  
Chenguang Xiao ◽  
Zhenshuai Wan ◽  
Shiqi Zhang ◽  
Xiaodong Zhang
Keyword(s):  
Dead Zone ◽  
Harmonic Distortion ◽  
Harmonic Component ◽  
Weight Vector ◽  
Shaking Table ◽  
Acceleration Response ◽  
Good Convergence ◽  
Acceleration Signal ◽  
True Value ◽  
Hydraulic Servo

Since the electro-hydraulic servo shaking table exists many nonlinear elements, such as, dead zone, friction and blacklash, its acceleration response has higher harmonics which result in acceleration harmonic distortion, when the electro-hydraulic system is excited by sinusoidal signal. For suppressing the harmonic distortion and precisely identify harmonics, a combination of the adaptive linear neural network and least mean M-estimate (ADALINE-LMM), is proposed to identify the amplitude and phase of each harmonic component. Namely, the Hampel’s three-part M-estimator is applied to provide thresholds for detecting and suppressing the error signal. Harmonic generators are used by this harmonic identification scheme to create input vectors and the value of the identified acceleration signal is subtracted from the true value of the system acceleration response to construct the criterion function. The weight vector of the ADALINE is updated iteratively by the LMM algorithm, and the amplitude and phase of each harmonic, even the results of harmonic components, can be computed directly online. The simulation and experiment are performed to validate the performance of the proposed algorithm. According to the experiment result, the above method of harmonic identification possesses great real-time performance and it has not only good convergence performance but also high identification precision.

scholarly journals Acceleration Harmonics Identification for an Electro-Hydraulic Servo Shaking Table Based on a Nonlinear Adaptive Algorithm

2018 ◽  
Vol 8 (8) ◽  
pp. 1332 ◽  
Author(s):  
Jianjun Yao ◽  
Chenguang Xiao ◽  
Zhenshuai Wan ◽  
Shiqi Zhang ◽  
Xiaodong Zhang
Keyword(s):  
Dead Zone ◽  
Harmonic Distortion ◽  
Harmonic Component ◽  
Weight Vector ◽  
Shaking Table ◽  
Acceleration Response ◽  
Good Convergence ◽  
Acceleration Signal ◽  
True Value ◽  
Hydraulic Servo

Since the electro-hydraulic servo shaking table came into existence, many nonlinear elements, such as, dead zone, friction and backlash, as well as its acceleration response has higher harmonics which result in acceleration harmonic distortion, when the electro-hydraulic system is excited by sinusoidal signal. For suppressing the harmonic distortion and precisely identify harmonics, a combination of the adaptive linear neural network and least mean M-estimate (ADALINE-LMM), is proposed to identify the amplitude and phase of each harmonic component. Specifically, the Hampel’s three-part M-estimator is applied to provide thresholds for detecting and suppressing the impulse noise. Harmonic generators are used by this harmonic identification scheme to create input vectors and the value of the identified acceleration signal is subtracted from the true value of the system acceleration response to construct the criterion function. The weight vector of the ADALINE is updated iteratively by the LMM algorithm, and the amplitude and phase of each harmonic, even the results of harmonic components, can be computed directly online. The simulation and experiment are performed to validate the performance of the proposed algorithm. According to the experiment result, the above method of harmonic identification possesses great real-time performance and it has not only good convergence performance but also high identification precision.

scholarly journals Acceleration Harmonic Estimation for Hydraulic Servo Shaking Table Based on Multi-Innovation Stochastic Gradient Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Xiancheng Wang ◽  
Wei Li ◽  
Jianjun Yao ◽  
Zhenshuai Wan
Keyword(s):  
Harmonic Distortion ◽  
Stochastic Gradient ◽  
Shaking Table ◽  
Gradient Algorithm ◽  
Phase Lag ◽  
Good Convergence ◽  
Acceleration Signal ◽  
Stochastic Gradient Algorithm ◽  
Hydraulic Servo ◽  
Convergence Performance

As one of the critical test equipment, hydraulic servo shaking table is widely used in shaking environment simulation of structural components and systems. However, inherent nonlinear factors of a hydraulic servo shaking table can cause amplitude attenuation and phase lag when corresponding to a sinusoidal acceleration signal, which leads to serious harmonic distortion. In order to improve waveform reproduction performance of sinusoidal signals, the amplitude and phase of harmonic should be estimated accurately. In this paper, the multi-innovation stochastic gradient (MISG) algorithm is presented for dynamically estimating the harmonic information. Simulation and experiment results demonstrate that the proposed algorithm has high estimation precision and good convergence performance.

scholarly journals Acceleration Harmonic Estimation in a Hydraulic Shaking Table Using Water Cycle Algorithm

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jianjun Yao ◽  
Zhenshuai Wan ◽  
Yu Fu
Keyword(s):  
Water Cycle ◽  
Estimation Algorithm ◽  
Weight Vector ◽  
Shaking Table ◽  
Control Performance ◽  
Acceleration Response ◽  
Water Cycle Algorithm ◽  
Time Performance ◽  
Rivers And Streams ◽  
Shock Resistance

Hydraulic shaking table is mainly used to stimulate the desired vibration environment and evaluate the shock resistance of structure. However, due to the inherent nonlinearities of the hydraulic shaking table, the acceleration response displays amplitude attenuation and phase delay for sinusoidal excitation signal. The distorted response degrades the control performance and even leads to an increase in system instability. In this paper, the water cycle algorithm (WCA), a recently developed metaheuristic method, is developed to estimate the harmonic information such as amplitude and phase. The basic idea of the proposed algorithm is inspired from nature and based on the observation of water cycle process and how rivers and streams flow to the sea in the nature world. The estimation process based on WCA is sequentially updating the weight vector of the signal. The amplitude and phase of fundamental as well as each harmonic can be achieved when the objective function is minimized. Simulation and experimental results demonstrate that the proposed harmonic estimation algorithm has good real-time performance, fast convergence, and excellent accuracy.

An Artificial Bee Colony Algorithm for Solving Hydraulic Shaking Table Acceleration Harmonic Estimation Problem

2018 ◽  
Author(s):  
Jianjun Yao ◽  
Zhenshuai Wan ◽  
Yu Fu ◽  
Tang Sheng ◽  
Ming Yang
Keyword(s):  
Artificial Bee Colony Algorithm ◽  
Artificial Bee Colony ◽  
Harmonic Distortion ◽  
Harmonic Component ◽  
Shaking Table ◽  
Construction Engineering ◽  
Time Performance ◽  
Bee Colony ◽  
Seismic Simulation ◽  
Component Estimation

Hydraulic shaking table is an important device to stimulate vibration environment, which has been widely applied to seismic simulation, aerospace and construction engineering. However, the response from the hydraulic shaking table are not considered sinusoid waveform when corresponds to a sinusoidal acceleration excitation due to the presence of harmonic distortion. This work presents an approach based on the artificial bee colony (ABC) algorithm for the harmonic component estimation in a hydraulic shaking table. The results demonstrate that the proposed method can precisely identify the harmonic component and it has great advantage of convergence as well as real-time performance.

The Harmonic Suppression Strategies and Efficiency Analysis of Electric Vehicle Induction Motor Drive System

2015 ◽  
Vol 734 ◽  
pp. 336-339
Author(s):  
Gang Qin ◽  
Jian Xiao Zou ◽  
Xiao Shuai Xin ◽  
Hong Bing Xu
Keyword(s):  
Voltage Drop ◽  
Dead Zone ◽  
Asynchronous Motor ◽  
Harmonic Distortion ◽  
Harmonic Component ◽  
Drive System ◽  
Motor Drive ◽  
Harmonic Suppression ◽  
Power Switches ◽  
Motor Drive System

The dead zone and voltage drop of inverter power switches make the currents in asynchronous motor drive system contain a large amount of harmonic. This aberration of currents waveform influences the efficiency of motor drive system. Aim at this problem, this paper proposes a harmonic injection method to eliminate the currents harmonic component when the motor is running, which improves currents waveform of motor and boosts efficiency of motor drive system. The effectiveness and real-time performance of this algorithm is verified via the simulation and the contrast experiment. Through the result of simulation, five times harmonic content decreased from 9% to 2%, the total harmonic distortion of voltage (THD) decreased from 6% to 2%, and efficiencyis increased from 98.99% to 99.95%.

Seismic Response of Pile Groups Improved with Deep Cement mixing Columns in Liquefiable Sand: Shaking Table Tests

2021 ◽  
Author(s):  
Dingwen Zhang ◽  
Anhui Wang ◽  
Xuanming Ding
Keyword(s):  
Seismic Behavior ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Pile Group ◽  
Shaking Table ◽  
Excess Pore Pressure ◽  
Shaking Table Tests ◽  
Pile Groups ◽  
Acceleration Response ◽  
Table Model

A series of shaking table model tests were performed to examine the effects of deep cement mixing (DCM) columns with different reinforcement depths on the seismic behavior of a pile group in liquefiable sand. Due to the DCM column reinforcement, the fundamental natural frequency of the model ground increases noticeably. The excess pore pressure of soils reduces with the increase of reinforcement depths of the DCM columns. Before liquefaction, the acceleration response of soils in the improved cases is obviously lower than that in the unimproved case, but the acceleration attenuation is greater after liquefaction in the unimproved case. Moreover, the lateral displacement of the superstructure, the settlement of the raft, and the bending moment of the piles in the improved cases are significantly reduced compared to those in the unimproved case, and the reduction ratios rise with the increase of reinforcement depth of the DCM columns. However, reinforcement by the DCM columns may result in the variation of the location of the maximum moment that occurs in the pile.

scholarly journals Seismic Response and Vibration Reduction Analysis of Suspended Structure under Wave Passage Excitation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Wenhua Cai ◽  
Bujun Yu ◽  
Fajong Wu ◽  
Jianhua Shao
Keyword(s):  
Seismic Response ◽  
Wave Velocity ◽  
Vibration Reduction ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Uniform Motion ◽  
Acceleration Response ◽  
Maximum Acceleration ◽  
Damping Effect ◽  
Suspended Structure

In order to study the influence of traveling wave effect on the seismic response and damping effect of suspended structure, a series of shaking table tests of the 1 : 20 suspended structure have been carried out to compare and analyze the dynamic responses of suspended structures under two points and a consistent input. The vibration damping effect and vibration reduction law of suspended structure are discussed at different apparent wave velocity and in the different connection. The research shows that the damping suspended structure has a good damping effect, and the amplitude reduction of the top displacement peak response is up to 15%, which corresponds to smaller apparent velocities. Moreover, the upper bound of the maximum acceleration response at the structures’ top under nonuniform input motions equals that of the uniform motion. However, there is a hysteresis in the acceleration response under wave travelling excitations, and the smaller the apparent wave velocity, the more obvious the hysteresis.

Effect of Nonlinear Characteristic of the Gas Turbine Engine Fuel System With Hardware-in-the-Loop

2018 ◽  
Author(s):  
Jinwei Chen ◽  
Jingxuan Li ◽  
Shengnan Sun ◽  
Huisheng Zhang
Keyword(s):  
Gas Turbine ◽  
Dead Zone ◽  
Gas Turbine Engine ◽  
Supply System ◽  
Hardware In The Loop ◽  
Nonlinear Characteristics ◽  
Turbine Engine ◽  
Zone Width ◽  
Servo Actuator ◽  
Hydraulic Servo

Fuel supply system, the regulation system for fuel delivery to the combustor, is one of the most important auxiliary systems in a gas turbine engine. Commonly, the fuel supply system was always simplified as a linear system. In fact, gas turbine engines almost use a hydromechanical main fuel control system which consists of electro-hydraulic servo actuator and fuel metering unit. These components have several nonlinear characteristics such as hysteresis, dead zone, relay, and saturator. These nonlinear characteristics can directly affect the performance a gas turbine engine. In this paper, a three-shaft gas turbine engine was taken as a research object. Firstly, a mechanism model of the fuel control system considering the nonlinear links was developed based on the hydro-mechanical theory. Then, the effect of dead zone-relay characteristic of the servo amplifier in electro-hydraulic servo actuator was analyzed. The results show that the dead zone width has great effect on the dynamic performance of the gas turbine engine. The fuel flow rate will be oscillating with small dead zone width. The parameters of the gas turbine engine will be stable with the increase of dead zone width. However, the larger dead zone width causes the hysteresis and the increase of the dynamic response time. At the same time, an improvement method with a two-dimensional fuzzy compensation was proposed. The results show that the fuzzy compensation can effectively solve the oscillation problem caused by the dead zone-delay. Finally, a Hardware-In-the-Loop (HIL) system is developed which is based on an electro-hydraulic servo actuator facility and a real-time software component of the gas turbine engine. An experiment is conducted on the HIL test rig to validate simulation result. The results show that the experiment matches well with the simulation results.

Delay compensation position tracking control of electro-hydraulic servo systems based on a delay observer

2019 ◽  
Vol 234 (5) ◽  
pp. 622-633
Author(s):  
Xingya Ding ◽  
Gang Shen ◽  
Xiang Li ◽  
Yu Tang
Keyword(s):  
Position Control ◽  
Signal Transmission ◽  
Experimental Results ◽  
Shaking Table ◽  
Feedback Signal ◽  
Delay Compensation ◽  
Servo Systems ◽  
Hybrid Controller ◽  
Hydraulic Servo ◽  
Backstepping Controller

In this article, the position control problem of electro-hydraulic servo systems with feedback signal transmission delay is studied. In order to improve the control accuracy of the system, a hybrid controller which combines a delay observer, a nonlinear disturbance observer and a backstepping controller is proposed. The controller has the characteristics of compensating the delay of signal transmission, restraining the uncertain disturbance of control systems and high control precision. In order to verify the stability and validity of the proposed hybrid controller, a single-degree-of-freedom electro-hydraulic shaking table is used to verify the experimental results. The experimental results show that the proposed controller has better control effects than proportional integral derivative and backstepping controller.

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