Robust adaptive vibration control for a string with time-varying output constraint

2018 ◽  
Vol 28 (17) ◽  
pp. 5213-5231 ◽  
Author(s):  
Wei He ◽  
Zhe Jing ◽  
Xiuyu He ◽  
Jin-Kun Liu ◽  
Changyin Sun
Keyword(s):  
Vibration Control ◽  
Time Varying ◽  
Robust Adaptive ◽  
Adaptive Vibration Control ◽  
Output Constraint

Robust adaptive vibration control of an underactuated flexible spacecraft

2018 ◽  
Vol 25 (4) ◽  
pp. 834-850 ◽  
Author(s):  
H. MoradiMaryamnegari ◽  
A.M. Khoshnood
Keyword(s):  
Rigid Body ◽  
Vibration Control ◽  
Control Method ◽  
Frequency Estimation ◽  
Equations Of Motion ◽  
Rigid Bodies ◽  
Lagrange Equations ◽  
Flexible Bodies ◽  
Robust Adaptive ◽  
Adaptive Vibration Control

Designing a controller for multi-body systems including flexible and rigid bodies has always been one of the major engineering challenges. Equations of motion of these systems comprise extremely nonlinear and coupled terms. Vibrations of flexible bodies affect sensors of rigid bodies and might make the system unstable. Introducing a new control strategy for designing control systems which do not require the rigid–flexible coupling model and can dwindle vibrations without sensors or actuators on flexible bodies is the purpose of this paper. In this study, a spacecraft comprising a rigid body and a flexible panel is used as the case study, and its equations of motion are extracted using Lagrange equations in terms of quasi-coordinates. For oscillations on a rigid body to be eliminated, a frequency estimation algorithm and an adaptive filtering are used. A controller is designed based on the rigid model of the system, and then robust stability conditions for the rigid–flexible system are obtained. The conditions are also developed for the spacecraft with more than one active frequency. Finally, the robust adaptive vibration control system is simulated in the presence of resonance. Simulations’ results indicate the advantage of the control method even when several active frequencies simultaneously resonate the dynamics system.

Vibration control using a beam-like adaptive tuned vibration absorber with an actuator-incorporated mass element

2009 ◽  
Vol 223 (7) ◽  
pp. 1555-1567 ◽  
Author(s):  
P Bonello ◽  
K H Groves
Keyword(s):  
Vibration Control ◽  
Effective Mass ◽  
Tuning Range ◽  
Excitation Frequency ◽  
Vibration Absorber ◽  
Time Varying ◽  
Additional Advantage ◽  
Expected Performance ◽  
Vibration Attenuation ◽  
Tuned Vibration Absorber

An adaptive tuned vibration absorber (ATVA) can retune itself in response to a time-varying excitation frequency, enabling effective vibration attenuation over a range of frequencies. For a wide tuning range the ATVA is best realized through the use of a beam-like structure whose mechanical properties can be adapted through servo-actuation. This is readily achieved either by repositioning the beam supports (‘moveable-supports ATVA’) or by repositioning attached masses (‘moveable-masses ATVA’), with the former design being more commonly used, despite its relative constructional complexity. No research to date has addressed the fact that the effective mass of such devices varies as they are retuned, thereby causing a variation in their attenuation capacity. This article derives both the tuned frequency and effective mass characteristics of such ATVAs through a unified non-dimensional modal-based analysis that enables the designer to quantify the expected performance for any given application. The analysis reveals that the moveable-masses concept offers significantly superior vibration attenuation. Motivated by this analysis, a novel ATVA with actuator-incorporated moveable masses is proposed, which has the additional advantage of constructional simplicity. Experimental results from a demonstrator correlate reasonably well with the theory, and vibration control tests with logic-based feedback control demonstrate the efficacy of the device.

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