Parametric modelling and dynamic characterization of a two-degree-of-freedom twin-rotor multi-input multi-output system

A mathematical model for the dynamic characterization of a two-degree-of-freedom (2 DOF) twin-rotor multi-input multi-output (MIMO) system (TRMS) in hover is extracted using a black box system identification technique. The behaviour of the TRMS, in certain aspects, resembles that of a helicopter, with a significant cross-coupling between longitudinal and lateral directional motions. Hence, it is an interesting identification and control problem. Identification for a 2 DOF, rigid-body, discrete-time linear model is presented in detail. The extracted model has a good degree of prediction capability. The modelling approach presented is suitable for complex new-generation air vehicles.

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Dynamic Characterization of Two‐Degree‐of‐Freedom Equipment‐Structure Systems

Journal of Engineering Mechanics ◽

10.1061/(asce)0733-9399(1985)111:1(1) ◽

1985 ◽

Vol 111 (1) ◽

pp. 1-19 ◽

Cited By ~ 76

Author(s):

Takeru Igusa ◽

Armen Der Kiureghian

Keyword(s):

Degree Of Freedom ◽

Dynamic Characterization ◽

Two Degree Of Freedom

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Dynamic modelling and linear quadratic Gaussian control of a twin-rotor multi-input multi-output system

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1177/095965180321700304 ◽

2003 ◽

Vol 217 (3) ◽

pp. 203-227 ◽

Cited By ~ 7

Author(s):

S M Ahmad ◽

A J Chipperfield ◽

M O Tokhi

Keyword(s):

Mimo System ◽

Dynamic Modelling ◽

Linear Quadratic ◽

Linear Quadratic Gaussian ◽

Control Effort ◽

Stability Augmentation ◽

Identification Technique ◽

High Control ◽

And Control ◽

Twin Rotor

This paper presents an investigation into the modelling and control of a one-degree-of-freedom (1 DOF) twin-rotor multi-input multi-output (MIMO) system (TRMS). The behaviour of the TRMS in certain aspects resembles that of a helicopter. Hence, it is an interesting identification and control problem. A dynamic model characterizing the TRMS in hover is extracted using a black-box system identification technique. The extracted model is employed in the design of a feedback linear quadratic Gaussian compensator, namely the stability augmentation system (SAS). This has a good tracking capability but requires high control effort and has inadequate authority over residual vibration of the system. These problems are resolved by further augmenting the system with a command path prefilter, resulting in the command and stability augmentation system (CSAS). The combined feedforward and feedback compensator satisfies the performance objectives and obeys the actuator constraint. The control law is implemented in realtime on the TRMS platform.

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Dynamic Characterization of a Two Degree of Freedom Planetary Gearbox During Varying Load Conditions

Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy ◽

10.1115/gt2019-91862 ◽

2019 ◽

Author(s):

Claudia González-Cruz ◽

Juan Jauregui ◽

Marco Ceccarelli

Keyword(s):

Load Condition ◽

Nonlinear Behavior ◽

Degree Of Freedom ◽

Operating Speed ◽

Dynamic Characterization ◽

Radial Vibrations ◽

Planetary Gearbox ◽

Input Shaft ◽

Two Degree Of Freedom

Abstract This paper presents the dynamic characterization of a two degree of freedom planetary gearbox prototype during the variation of the load condition. Tests with varying load are developed at three different operating speeds of the input shaft: 190, 380 and 590 rpm. The dynamic torques and vibrations on the input and output shafts are acquired during the experiments, such as the angular velocity of the output shaft. The experimental data are analyzed to evaluate the dynamics of the system during the exchange of operation between the first and second DOF operation. Then, the radial vibrations are analyzed during the operation of the second DOF by means of a methodology using different signal processing tools: first, the continuous wavelet transform is used to identify the nonlinear behavior and the main frequency content of the system; then, the vibrations are filtered by means of passband filters in order to keep the main frequencies of the system and delete any other; finally, the filtered signals are analyzed with both, the Kuramoto’s order parameter to quantify the dynamic synchronization of the gearbox and the phase diagram to characterize its stability. The results demonstrates the utility of the second DOF in the design of the planetary gearbox in order to avoid excessive torques in the components of the system. Furthermore, it is found that the synchronization of the system increases at higher operating speed, however, the system becomes unstable as the operating speed is increased.

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Two-Degree-of-Freedom Helicopter Closed-Loop Identification through a Cascade Controller

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.403-408.4649 ◽

2011 ◽

Vol 403-408 ◽

pp. 4649-4658 ◽

Cited By ~ 1

Author(s):

Pouya Ghalei ◽

Alireza Fatehi ◽

Mohamadreza Arvan

Keyword(s):

Closed Loop ◽

Flight Simulation ◽

Degree Of Freedom ◽

Input Output ◽

Closed Loop Identification ◽

Practical Algorithm ◽

Nonlinear Autoregressive Model ◽

And Control ◽

Nonlinear Autoregressive ◽

Two Degree Of Freedom

Input-Output data modeling using multi layer perceptron networks (MLP) for a laboratory helicopter is presented in this paper. The behavior of the two degree-of-freedom platform exemplifies a high order unstable, nonlinear system with significant cross-coupling between pitch and yaw directional motions. This paper develops a practical algorithm for identifying nonlinear autoregressive model with exogenous inputs (NARX) and nonlinear output error model (NOE) through closed loop identification. In order to collect input-output identifier pairs, a cascade state feedback (CSF) controller is introduced to stabilize the helicopter and after that the procedure of system identification is proposed. The estimated models can be utilized for nonlinear flight simulation and control and fault detection studies.

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