Discrete-Time, Closed-Loop Aeromechanical Stability Analysis of Helicopters with Higher Harmonic Control

2007 ◽  
Vol 30 (5) ◽  
pp. 1249-1260 ◽  
Author(s):  
Marco Lovera ◽  
Patrizio Colaneri ◽  
Carlos Malpica ◽  
Roberto Celi
Keyword(s):  
Stability Analysis ◽  
Discrete Time ◽  
Closed Loop ◽  
Harmonic Control ◽  
Higher Harmonic Control ◽  
Higher Harmonic ◽  
Aeromechanical Stability

Closed-Loop Aeromechanical Stability of Hingeless Rotor Helicopters with Higher Harmonic Control

2006 ◽  
Vol 29 (1) ◽  
pp. 179-189 ◽  
Author(s):  
Marco Lovera ◽  
Patrizio Colaneri ◽  
Carlos Malpica ◽  
Roberto Celi
Keyword(s):  
Closed Loop ◽  
Harmonic Control ◽  
Higher Harmonic Control ◽  
Higher Harmonic ◽  
Aeromechanical Stability

scholarly journals Investigation of Linear Higher Harmonic Control Algorithm for Rotorcraft Vibration Reduction

2020 ◽  
Author(s):  
Byeonguk Im ◽  
Changbae Lee ◽  
YoungJung Kee ◽  
Sangjoon Shin
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
Linear Time ◽  
Control Input ◽  
Phase Lag ◽  
Linear Quadratic ◽  
Invariant Representation ◽  
Harmonic Control ◽  
Higher Harmonic Control ◽  
Higher Harmonic

Abstract A linear quadratic Gaussian controller for active vibratory loads reduction in helicopters is proposed based on a revisited higher harmonic control input by active trailing-edge flaps. Conventional individual blade control input is redefined using N-1/rev inter-blade phase lead, N/rev collective, and N+1/rev inter-blade phase lag signals where 1/rev frequency modulation originate from the multi-blade coordinate transform. A Mach-scaled flap blade is designed and analyzed by the multi-body dynamics analysis DYMORE. A linear time-invariant representation is identified from N/rev envelopes of the input and output responses obtained by DYMORE analysis. A MATLAB/Simulink closed-loop control simulation is designed using the identified state-space realization. The N/rev vibratory loads are reduced up to 52% with flap deflections and the linear control results match well with the nonlinear responses obtained from DYMORE. Furthermore, the multi-variable closed-loop stability estimated by the loop transfer functions using disk margin analysis reveals sufficient gain and phase margins.

Effects of higher harmonic control on rotor performance and control loads

1992 ◽  
Vol 29 (3) ◽  
pp. 336-342 ◽  
Author(s):  
Khanh Nguyen ◽  
Inderjit Chopra
Keyword(s):  
Harmonic Control ◽  
Higher Harmonic Control ◽  
Higher Harmonic ◽  
And Control

A Higher Harmonic Control Test in the DNW to Reduce Impulsive BVI Noise

1994 ◽  
Vol 39 (4) ◽  
pp. 3-13
Author(s):  
Wolf R. Splettstoesser ◽  
Klaus‐J. Schultz ◽  
Roland Kube ◽  
Thomas F. Brooks ◽  
Earl R. Booth ◽  
...  
Keyword(s):  
Control Test ◽  
Harmonic Control ◽  
Higher Harmonic Control ◽  
Higher Harmonic

Effects of Two/rev Higher Harmonic Control on Rotor Performance

2003 ◽  
Vol 48 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Rendy P. Cheng ◽  
Colin R. Theodore ◽  
Roberto Celi
Keyword(s):  
Harmonic Control ◽  
Higher Harmonic Control ◽  
Higher Harmonic

Stability analysis of a discrete-time system with a variable-, fractional-order controller

2010 ◽  
Vol 58 (4) ◽  
pp. 613-619 ◽  
Author(s):  
P. Ostalczyk
Keyword(s):  
Stability Analysis ◽  
Fractional Order ◽  
Discrete Time ◽  
Closed Loop ◽  
Control Strategies ◽  
Discrete Time System ◽  
Time System ◽  
Matrix Condition Number ◽  
Fractional Order Controller ◽  
Matrix Condition

Stability analysis of a discrete-time system with a variable-, fractional-order controllerVariable, fractional-order backward difference is a generalisation of commonly known difference or sum. Equations with these differences can be used to describe a variable-, fractional order digital control strategies. One should mention, that classical tools such as a state-space description and discrete transfer function cannot be used in the analysis and synthesis of such a type of systems. Equations describing a closed-loop system are proposed. They contain square matrices imitating the action of matrices in the system polynomial matrix description. This paper focuses on the stability analysis of a closed-loop SISO linear system with a controller described by the equations mentioned. A stability condition based on a transient denominator matrix condition number is proposed. Investigations are supported by two numerical examples.

Switching Control Design for Switched Fuzzy Discrete-Time Systems

2014 ◽  
Vol 1006-1007 ◽  
pp. 711-714
Author(s):  
Hong Yang ◽  
Huan Huan Lü ◽  
Le Zhang
Keyword(s):  
Stability Analysis ◽  
Discrete Time ◽  
Fuzzy Systems ◽  
Closed Loop ◽  
Control Method ◽  
Control Design ◽  
Switching Control ◽  
Discrete Time Systems ◽  
The Stability ◽  
Time Systems

This paper investigates the problems of stability analysis and stabilization for a class of switched fuzzy discrete-time systems. Based on a common Lyapunov functional, a switching control method has been developed for the stability analysis of switched discrete-time fuzzy systems. A new stabilization approach based on a switching parallel distributed compensation scheme is given for the closed-loop switched fuzzy systems. Finally, the illustrative example is provided to demonstrate the effectiveness of the techniques proposed in this paper.

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