Nonlinearity-induced distortion of the transfer function shape in high-order OTA-C filters

1993 ◽  
Vol 3 (2) ◽  
pp. 143-151 ◽  
Author(s):  
Stanislaw Szczepanski ◽  
Rolf Schaumann
Keyword(s):  
Transfer Function ◽  
High Order ◽  
Function Shape

Lower-Order Active Disturbance Rejection Control and Frequency Analysis of High Order System

2017 ◽  
Author(s):  
Ruiqing Zhang ◽  
Shubo Zhang ◽  
Yali Xue ◽  
Yu Hu ◽  
Wendi Wang
Keyword(s):  
Transfer Function ◽  
Frequency Analysis ◽  
Lower Order ◽  
Disturbance Rejection ◽  
High Order ◽  
Order System ◽  
Active Disturbance Rejection Control ◽  
High Order System ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control

Linear active disturbance rejection control (LADRC) has been paid much attention in academic and industrial fields. However, the selection of the order for LADRC controller design and the choice of parameter b0 in system correcting are key facts which are still being faced by designer. In this paper, an effective method about how to select the order of LADRC and the parameter b0 is given first. Frequency analysis often used by engineers for designing controller, the normal transfer function form of LADRC is constructed, so the loop gain, close loop transfer function and disturbance transfer function to a general high-order system are presented and can be easily used. The example shows that the proposed method is easy to apply and verified the lower-order LADRC can obtain the better effective than PID and high-order LADRC, and the frequency response analysis of a thermal power plant is elaborated and the simulation result indicates that LADRC has a strong robustness against the large variation of parameters in the plant mode.

Pre-Estimating Dynamically the Optimum of Extremum Value Control System with Large Time Delay Element Based on Correlation Identification

2012 ◽  
Vol 591-593 ◽  
pp. 1558-1562
Author(s):  
Guo Qiang Li ◽  
Yong Qin Liu ◽  
Wen Jiang Liu
Keyword(s):  
Control System ◽  
Time Delay ◽  
Transfer Function ◽  
Large Time ◽  
Linear Part ◽  
High Order ◽  
Delay Element ◽  
System A ◽  
Extremum Value ◽  
Derivation Process

As to the optimum of extremum value controlled plant, if the transfer function of its linear part is only with the high order dynamic elements, the optimum of extremum value control system could be dynamically pre-estimated by using the method based on correlation identification we presented, the pre-estimating method has the estimate speed quickly, anti-jamming ability strong, accurate, highly effective and so on the merits. However, if the controlled plant is simultaneously with high order dynamic elements and a large time delay element, the method could not be used directly to pre-estimate dynamically the optimum of the extremum value control system. A new improved pre-estimating method is presented so as to resolve the problem above. After we have in detail analyzed the derivation process of the pre-estimating method we presented, Fully taking into account the effects of large time-delay element, a number of conditions have been improved, the algorithm based on correlation identification has been extended, the optimum of extremum value control system with a large time delay element is well resolved by the extended algorithm.

The Measurement of Resonances in High Order Transfer Functions

1969 ◽  
Vol 2 (3) ◽  
pp. 102-103
Author(s):  
R. W. Levinge
Keyword(s):  
Transfer Function ◽  
Transfer Functions ◽  
High Order ◽  
Damping Factor ◽  
Phase Slope

The frequency and damping factor of resonances in a high order transfer function may be obtained accurately by measuring Normalised Phase Slope.

scholarly journals A High-Order Load Model and the Control Algorithm for an Aerospace Electro-Hydraulic Actuator

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 53
Author(s):  
Shoujun Zhao ◽  
Keqin Chen ◽  
Xiaosha Zhang ◽  
Yingxin Zhao ◽  
Guanghui Jing ◽  
...  
Keyword(s):  
Transfer Function ◽  
Fourth Order ◽  
Dynamic Pressure ◽  
Resonance Effect ◽  
Notch Filter ◽  
High Order ◽  
Model Parameters ◽  
Hydraulic Actuator ◽  
Control Block ◽  
Load Model

It is difficult to describe precisely, and thus control satisfactorily, the dynamics of an electro-hydraulic actuator to drive a high thrust liquid launcher engine, whose structural resonant frequency is usually low due to its heavy inertia and complicated mass distribution, let alone one to drive a heavy kerolox engine with high-order dynamics. By transforming classic control block diagrams, a baseline two-mass-two-spring load model and a normalized actuator-engine system model were developed for understanding the basic physics and methodology, where a fourth-order transfer function is used to model the multi-resonance-frequency engine body outside of the rod position loop, another fourth-order transfer function with two pairs of conjugated zeros and poles to represent the composite hydro-mechanical resonance effect in the closed rod position loop. A sixth-order model was thereafter proposed for even higher dynamics. The model parameters were identified and optimized by a full factor search approach. To meet the stringent specification of static and dynamic performances, it was demonstrated that a notch filter network combined with other controllers is needed since the traditional dynamic pressure feedback (DPF) is difficult to handle the high-order dynamics. The approach has been validated by simulation, experiments and successful flights. The models, analysis, data and insights were elaborated.

Sign in / Sign up

Export Citation Format

Share Document