scholarly journals Experimental evaluation of the parameter-based closed-loop transfer function identification for electro-hydraulic servo systems

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668442 ◽  
Author(s):  
Guang-Da Liu ◽  
Ge Li ◽  
Gang Shen
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
Servo System ◽  
Proportional Integral Derivative ◽  
Servo Systems ◽  
Closed Loop Systems ◽  
Loop Transfer Function ◽  
Tracking Controllers ◽  
Hydraulic Servo ◽  
Hydraulic Servo System

Closed-loop systems of an electro-hydraulic servo system including position, acceleration, and force closed-loop systems and their closed-loop transfer functions based on parameter model are adaptive identified using a recursive extended least-squares algorithm. The position and force closed-loop tracking controllers are designed by a proportional–integral–derivative controller and are tuned by the position and force step signals. The acceleration closed-loop tracking controller is designed by a three-variable controller and the three states include position, velocity, and acceleration. Experimental results of the estimated position, acceleration, and force closed-loop transfer functions are performed on an actual electro-hydraulic servo system using xPC rapid prototyping technology, which clearly demonstrate the benefit of the adaptive identification method.

Slide - Mode Variable Structure Adaptive Control of Electro-Hydraulic Servo Systems Based on LuGre Friction Model

2014 ◽  
Vol 687-691 ◽  
pp. 371-374 ◽  
Author(s):  
Rui Juan Guo ◽  
Shuang Du ◽  
Hui Min Yin
Keyword(s):  
Sliding Mode ◽  
Servo System ◽  
Variable Structure ◽  
Friction Model ◽  
Interference Factor ◽  
Servo Systems ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
Sliding Mode Variable Structure ◽  
Noise Factors

Electro-hydraulic servo system has more disturbance and noise factors at low speed than in other situations of the whole operating process, so the stability and performances of the system would be greatly affected by these factors. It is generally accepted that nonlinear torque disturbance is the main interference factor. In order to compensate above disadvantages, a sliding mode variable structure control was proposed to adjust the electro-hydraulic servo system. The results indicate that the provided approach possesses satisfactory performances in stability, robustness, steady state error and so on.

scholarly journals Dual-valve parallel prediction control for an electro-hydraulic servo system

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987566
Author(s):  
Shi-jie Su ◽  
Yuan-yuan Zhu ◽  
Cun-jun Li ◽  
Wen-xian Tang ◽  
Hai-rong Wang
Keyword(s):  
Dynamic Response ◽  
Predictive Control ◽  
Servo System ◽  
High Flow ◽  
Control Performance ◽  
Proportional Integral Derivative ◽  
Hydraulic Servo ◽  
Response Performance ◽  
Hydraulic Servo System ◽  
Control Accuracy

To improve the dynamic response performance of a high-flow electro-hydraulic servo system, scholars have conducted considerable research on the synchronous and time-sharing controls of multiple valves. However, most scholars have used offline optimization to improve control performance. Thus, control performance cannot be dynamically adjusted or optimized. To repeatedly optimize the performance of multiple valves online, this study proposes a method for connecting a high-flow proportional valve in parallel with a low-flow servo valve. Moreover, this study proposes an algorithm in which a proportional–integral–derivative system and multivariable predictive control system are used as an inner loop and outer loop, respectively. The simulation and experimental results revealed that dual-valve parallel control could effectively improve the control accuracy and dynamic response performance of an electro-hydraulic servo system and that the proportional-integral-derivative–multivariable predictive control controller could further dynamically improve the control accuracy.

Design of an Experimental Platform for Hydraulic Servo System

2011 ◽  
Vol 69 ◽  
pp. 51-54
Author(s):  
Jin Fang Zhu
Keyword(s):  
Hydraulic System ◽  
Servo System ◽  
Hydraulic Cylinder ◽  
Hydraulic Motor ◽  
Electronic Components ◽  
Servo Systems ◽  
Experimental Platform ◽  
Overall Design ◽  
Hydraulic Servo ◽  
Hydraulic Servo System

VRLA (valve-regulated lead-acid) and Pump-control are the two kinds of power components for hydraulic servo system. With different command device, feedback measurement device and different corresponding electronic components, the hydraulic servo systems are different. To ensure maximum performance of the whole device, the overall design (including mechanical, electrical design) should be considered for hydraulic servo system. Machinery-electric-hydraulic should be in coordination with each other. The hydraulic system components are used to change the speed of hydraulic cylinder and alter direction of hydraulic cylinder and hydraulic motor. The solenoid valve for motor and hydraulic servo system and the control of pressure relay can implement by the electric section.

Health Assessment of Hydraulic Servo System Based on Fractal Analysis and Gaussian Mixture Model

2015 ◽  
Vol 764-765 ◽  
pp. 703-707
Author(s):  
Xuan Wang ◽  
Hong Mei Liu ◽  
Chen Lu
Keyword(s):  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Fractal Analysis ◽  
Health Assessment ◽  
Servo System ◽  
Gaussian Mixture ◽  
Servo Systems ◽  
Feature Vectors ◽  
Hydraulic Servo ◽  
Hydraulic Servo System

A hydraulic servo system is a typical feedback control system. Health assessment of a hydraulic servo system is usually difficult to realize when traditional methods based on sensor signals are utilized. An approach for health assessment of hydraulic servo systems based on multi-fractal analysis and Gaussian mixture model (GMM) is proposed in this study. A GRNN neural network is employed to establish a fault observer for the hydraulic servo system. The observer is utilized to simulate the system output under normal state. The residue is then generated by subtracting the estimated output from the actual output. The residue’s feature is extracted by fractal analysis. After the feature extraction, the overlap between the current feature vectors and the normal feature vectors is obtained by applying GMM. The confidence value (CV) can be obtained in advance; this value is employed to characterize the health degree of the current state and consequently implement the health assessment of the hydraulic servo system. Lastly, two common types of fault, namely, burst and gradual, are applied to validate the effectiveness of the proposed method.

Model Reference Adaptive Control on a Hydraulic Servo System

2011 ◽  
Vol 268-270 ◽  
pp. 505-508
Author(s):  
Zhi Yong Qu ◽  
Zheng Mao Ye
Keyword(s):  
Servo System ◽  
Adaptive Controller ◽  
Fast Response ◽  
System Stability ◽  
Servo Systems ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
Simulation Results ◽  
The Stability ◽  
Model Reference Adaptive

Hydraulic servo systems are usually used in industry. This kind of system is nonlinear in nature and generally difficult to control. The ordinary linear constant gain controller can cause overshoot or even loss of system stability. Application of adaptive controller to a nonlinear hydraulic servo system is investigated in this paper. The dynamic model of the system is given and the stability is also analyzed using Popov's criterion. The steady state error can be eliminated using adaptive controller combined with an integration term. Simulation results show the performance of adaptive controller with fast response and less overshoot

A bifurcation-based procedure for designing and analysing robustly stable non-linear hydraulic servo systems

1998 ◽  
Vol 212 (5) ◽  
pp. 383-394 ◽  
Author(s):  
G G Kremer ◽  
D F Thompson
Keyword(s):  
Hopf Bifurcation ◽  
Parameter Space ◽  
Robust Stability ◽  
Servo System ◽  
High Dimensional ◽  
Dimensional Parameter ◽  
Servo Systems ◽  
Stability Robustness ◽  
Hydraulic Servo ◽  
Hydraulic Servo System

A critical evaluation of current hydraulic servo system analysis methods indicates a need for alternative methods better able to quantify robust stability. One promising method recently developed for analysing large-scale power systems determines stability robustness in a high-dimensional parameter space by computing the distance to the ‘closest’ Hopf bifurcation (which corresponds to the birth of a limit cycle oscillation). In this paper a procedure is developed for applying closest Hopf bifurcation theory in the design and analysis of robustly stable hydraulic servo systems. The procedure addresses practical implementation issues such as the impact of an inhomogeneous parameter space and the choice of a metric that yields a meaningful quantitative measure of stability robustness. Results from the new procedure applied to a common position control system compare favourably with published describing function results and new simulation results. Additionally, the new procedure is easier to apply and produces results which are easier to interpret and use. As a demonstration of the design procedure's ability to handle non-linear systems with high-dimensional parameter spaces, a hydraulic servo system with an inhomogeneous seven-dimensional parameter space is designed to meet a robust stability requirement.

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