Multi-Point Suspension Design and Stability Analysis of a Scaled Hoop Truss Antenna Structure

2021 ◽  
pp. 2150077
Author(s):  
Guoliang Ma ◽  
Minglong Xu ◽  
Longlei Dong ◽  
Zhuo Zhang
Keyword(s):  
Experimental Data ◽  
Stability Analysis ◽  
Transfer Function ◽  
Open Loop ◽  
Scaled Model ◽  
Antenna Structure ◽  
Loop Transfer Function ◽  
Before And After ◽  
Vibration Experiment ◽  
The Stability

This paper proposes a scaled model to investigate the dynamic characteristics and stability of a hoop truss antenna on the ground. First, the statically indeterminate equation for the multi-point suspension is established, along with the voltage of the suspension motor calculated. Then the transfer function of the system is theoretically established. The scaled model is established before and after suspension, and the static deformation and natural frequency of the system are obtained by calculation and measurement. There exist the shaking mode and nodding mode. Also, a vibration experiment is conducted for the system to obtain the vibration response. With this, the transfer function is identified by the system identification method, which appears to be of the second order, and the stability is analyzed through the zero pole diagram. The experiment results show that the first two frequencies are close before and after suspension. Moreover, the stability of the system can be judged by the open-loop transfer function. It is concluded that the vibration experimental data of the scaled model can be used as a reference for the large hoop truss antenna structure.

scholarly journals Modeling and Stability Analysis of Parallel Inverters in Island Microgrid

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 463 ◽  
Author(s):  
Xiaohuan Wang ◽  
Hongyang Qing ◽  
Peng Huang ◽  
Chunjiang Zhang
Keyword(s):  
Parallel System ◽  
Open Loop ◽  
Power Equipment ◽  
Control Methods ◽  
Impedance Model ◽  
Loop Transfer Function ◽  
Impedance Modeling ◽  
The Difference ◽  
Output Characteristics ◽  
The Stability

The island microgrid is composed of a large number of inverters and various types of power equipment, and the interaction between inverters with different control methods may cause system instability, which will cause the power equipment to malfunction. Therefore, effective methods for analyzing the stability of the microgrid system have become particularly important. Generally, impedance modeling methods are used to analyze the stability of power electronic converter systems. In this paper, the impedance models of a PQ-controlled inverter and droop-controlled inverter are established in d-q frame. In view of the difference of output characteristics between the two control methods, the island microgrid is equivalent to a double closed-loop system. The impedance model of the parallel system is derived and the open loop transfer function of the system is extracted. Based on the generalized Nyquist criterion (GNC), the stability of parallel system working in island microgrid mode is analyzed using this proposed impedance model. The simulation and experiment results are presented to verify the analysis.

Robust Feedback Control of a Baffled Plate via Open-Loop Optimization

2001 ◽  
Vol 124 (1) ◽  
pp. 154-157 ◽  
Author(s):  
P. De Man ◽  
A. Franc¸ois ◽  
A. Preumont
Keyword(s):  
Genetic Algorithm ◽  
Control System ◽  
Transfer Function ◽  
Open Loop ◽  
Displacement Sensor ◽  
Search Procedure ◽  
Loop Optimization ◽  
Loop Transfer Function ◽  
Poles And Zeros ◽  
Siso System

A SISO control system is built by using a volume displacement sensor and a set of actuators driven in parallel with a single amplifier. The actuators location is optimized to achieve an open-loop transfer function which exhibits alternating poles and zeros, as for systems with collocated actuators and sensors; the search procedure uses a genetic algorithm. The ability of a simple lead compensator to control this SISO system is numerically demonstrated.

Model-Based Control of Combustion Instabilities

2005 ◽  
Author(s):  
Aimee S. Morgans ◽  
Ann P. Dowling
Keyword(s):  
Transfer Function ◽  
Controller Design ◽  
Open Loop ◽  
Operating Conditions ◽  
Combustion Instabilities ◽  
Lean Premixed Combustion ◽  
Model Based Control ◽  
Model Based ◽  
Loop Transfer Function ◽  
Mathematical Approximation

Model-based control has been successfully implemented on an atmospheric pressure lean premixed combustion rig. The rig incorporated a pressure transducer in the combustor to provide a sensor measurement, with actuation provided by a fuel valve. Controller design was based on experimental measurement of the open loop transfer function. This was achieved using a valve input signal which was the sum of an identification signal and a control signal from an empirical controller to eliminate the non-linear limit cycle. The transfer function was measured for the main instability occurring at a variety of operating conditions, and was found to be fairly similar in all cases. Using Nyquist and H∞-loop shaping techniques, several robust controllers were designed, based on a mathematical approximation to the measured transfer function. These were implemented experimentally on the rig, and were found to stabilise it under a variety of operating conditions, with a greater reduction in the pressure spectrum than had been achieved by the empirical controller.

scholarly journals Analytical Multiloop Control for Multivariable Systems with Time Delays

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhiguo Wang ◽  
Peng Wei
Keyword(s):  
Transfer Function ◽  
Process Model ◽  
Controller Design ◽  
Design Method ◽  
Open Loop ◽  
Multivariable Systems ◽  
Performance Improvements ◽  
Loop Transfer Function ◽  
Multiloop Control ◽  
Multiloop Control System

In this paper, a new design method with performance improvements of multiloop controllers for multivariable systems is proposed. Precise expression is developed to show the relationship between the dynamic- and steady-state characteristics of the multiloop control system and its parameters. First, an equivalent transfer function (ETF) is introduced to decompose the multivariable system, based on which the multiloop controller parameters are calculated. According to the ETF matrix property, an analytical expression for the PI controller for multivariable systems is derived in terms of substituting the ETF matrix for the inverse open-loop transfer function. In the proposed controller design method, no approximation of the inverse of the process model is needed, implying that this method can be applied to some multivariable systems with high dimensions. The simulation results obtained from several examples demonstrate the effectiveness of the proposed method.

Theoretical Prediction of Onset of Horizontal Slug Flow

1980 ◽  
Vol 102 (4) ◽  
pp. 441-445 ◽  
Author(s):  
Kaichiro Mishima ◽  
Mamoru Ishii
Keyword(s):  
Experimental Data ◽  
Stability Analysis ◽  
Slug Flow ◽  
Flow Analysis ◽  
Finite Amplitude ◽  
Empirical Correlations ◽  
Deformation Limit ◽  
Theoretical Criterion ◽  
The Stability ◽  
Good Agreement

A criterion for the onset of a slug flow in a horizontal duct is derived theoretically. A potential flow analysis is carried out by considering waves of finite amplitude. The stability criterion is obtained by introducing the wave deformation limit and the “most dangerous wave” concept in the stability analysis. The present theoretical criterion for slug formation shows very good agreement with a large number of experimental data and with some empirical correlations.

Stability Determination for Linear Control Systems with Distributed Lags

1972 ◽  
Vol 5 (6) ◽  
pp. 238-241 ◽  
Author(s):  
F L N-Nagy ◽  
M N Al-Tikriti
Keyword(s):  
Control Systems ◽  
Open Loop ◽  
Linear Control ◽  
Linear Control Systems ◽  
Loop Gain ◽  
Variable Parameters ◽  
Distributed Lag ◽  
Distributed Lags ◽  
Loop Transfer Function ◽  
The Stability

The paper outlines a specially adapted stability criterion for linear control systems with distributed lags. The stability is studied with respect to two variable parameters, ie the loop-gain and the distributed lag. The criterion employs an easily constructed chart prepared beforehand and only requires the plotting of two curves derived from the open-loop transfer function. The stability of a simple control system is investigated to illustrate the scheme.

Stability of Ring-Stiffened Tubular Members Under External Pressure

1995 ◽  
Vol 117 (2) ◽  
pp. 150-155 ◽  
Author(s):  
S. A. Karamanos ◽  
J. L. Tassoulas
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Stability Analysis ◽  
External Pressure ◽  
Nonlinear Finite Element ◽  
Steel Tubes ◽  
Deformation Plasticity ◽  
The Stability ◽  
Element Technique ◽  
Stiffened Steel

This paper presents results of a rigorous nonlinear finite element technique for the stability analysis of ring-stiffened steel tubes under external pressure. Large deformation, plasticity, as well as residual stresses and imperfections, are taken into account. Both internal and external stiffeners are simulated. A study of various parameters which affect pressure capacity is summarized, along with a comparison with available experimental data.

Design of Passive Vibration Control Device Based on GKYP Lemma

2007 ◽  
Author(s):  
Song Zhang ◽  
Daisuke Iba ◽  
Akira Sone ◽  
Arata Masuda
Keyword(s):  
Transfer Function ◽  
Optimization Design ◽  
Difficult Problem ◽  
Control Device ◽  
Open Loop ◽  
Design Parameters ◽  
Pd Controller ◽  
Vibration System ◽  
Linear Control Theory ◽  
Loop Transfer Function

This paper proposes a new method that is an optimization design of a passive vibration system based on linear control theory. A Force generated by spring and damper that are the design parameters of the passive vibration system have the same properties with a PD controller. So it is possible to apply a method that shapes an open-loop transfer function of the PD controller based on the GKYP lemma. By using the method, the gain and the phase of the transfer function can be designed with respect to each frequency band. As a result, it is not necessary to solve a difficult problem that is a bilinear matrix inequality problem obtained by an ordinary formulation.

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